HAMMOCK SYSTEMS AND METHODS
A bridge hammock system comprises a suspension system and a load bearing sling. The suspension system comprises a suspension line and defines first and second ends. The load bearing sling has a load support surface region for supporting the load and a side panel region. The first end of the suspension system defines a first slope, and the second end of the suspension system defines a second slope. The side panel region supports the load support surface region from the suspension system. The side panel region integrates a curve of the suspension system with the load bearing surface region such that a collective slope of the suspension system is greater than zero, tension forces on the first end of the suspension system are substantially upwardly directed, and tension forces on the second end of the suspension system are at least one of substantially laterally and substantially downwardly directed.
This application (Attorney's Ref. No. P220137) is a 371 of International PCT Application No. PCT/US21/43319 filed Jul. 27, 2021, currently pending.
International PCT Application No. PCT/US21/43319 claims benefit of U.S. Provisional Application Ser. No. 63/056,976 filed Jul. 27, 2020, the contents of which are incorporated herein by reference.
TECHNICAL FIELDThe present invention relates to hammocks and, more specifically, to Bridge Style hammocks having suspension with a substantial collective slope.
BACKGROUNDA hammock is a type of sling made of pliable materials such as fabric, rope, or netting for suspending a human body or other load between two or more elevated points, whereby it may be used for swinging, sleeping, resting, storage or other purposes.
Hammocks have been used for centuries, primarily as seating or bedding for humans, but also variously for such uses as supporting fruit in the open air or providing entertaining seating for animals in the zoo. While the exact historical origins of the hammock cannot be ascertained, it is believed that they were originally developed by native inhabitants of the Caribbean, then subsequently gained extensive usage in Central and South America for sleeping. Later, Europeans adopted the concept for use aboard navy ships to maximize available space while providing safer, more comfortable birthing for sailors. Hammocks also found utility with explorers and soldiers traveling in wooded areas. Today, hammocks are popular around the world for relaxation, and the hammock is often seen as symbol of summer, leisure, and simple, easy living.
Hammocks used for human recumbence have developed into various configurations. The most basic, referred to herein as the Mayan or Brazilian style hammock, is simply a rather large rectangular piece of fabric having the smaller ends gathered and bound so that they can be attached to suspension points. These are typically hung with a deep sag—the body being positioned perpendicular to the length of the hammock when used as a seat, or diagonally to the hammock's length when used as a bed. The diagonal orientation enables a body to lay flat even though the hammock material forms an apparent U or V shape when viewed from one side.
Several western navies used hammocks as birthing aboard ships (hereinafter “Navy Style hammocks”) because hammocks could be stored very compactly when not in use and allowed maximal air circulation within sleeping quarters. The Navy Style was typically made from heavy cotton canvas with an array of rope lashing at each end to distribute the tension across the fabric edge. Navy-style devices were typically narrow, with the occupant laying parallel to the length, thus contributing to a curved body poster. Some examples were constructed with a box-like shape to mitigate this body posture, such that they began to take on some of the characteristics of a bridge hammock as discussed below, although they were not properly such. Some examples may have used modest spreaders, but most of record did not.
Two notable styles have dominated the leisure market for several decades. The simplest, referred to herein as the “Net Leisure” hammock, is prized for its compactness and relatively low cost. Net Leisure hammocks resemble the simplest Navy Style in the form of a basic sling, but rather than solid panels of cloth or canvas, the Net Leisure hammock is composed of knotted twine forming a net-like webbing. Because Net Leisure hammocks are generally too small to be slung like a Mayan Style, the occupant lies parallel to its length and is fairly restricted in their movements.
The other popular style in the North American and European markets will be referred to herein the “Spreader Leisure” hammock. Spreader Leisure hammocks, most commonly found in residential yards, are typically composed of a rectangular piece of netting or canvas and include a sizable spreader at each end to give the support portion thereof a flat, wide aspect.
The spreaders generally require the occupant to recline parallel to the length of the Spreader Leisure hammock such that the user's body conforms to the catenary shape of the suspended fabric. To reduce this curvature, these hammocks are typically slung tighter than the Navy Style and Net Leisure hammocks described above, giving the Spreader Leisure type hammock a comparatively flat, shallow bed surface. Although this curved posture is considered comfortable for short-term relaxation, many feel it is not suitable for a full night's sleep.
A more recent development, referred to herein as the Bridge Style hammock, has become popular with those using hammocks for wilderness camping, and utilizes the concept found in the suspension bridge to provide a more level position for the occupant as they lay parallel to its length, thus overcoming the discomfort associated with the curved body position of the leisure hammocks described above. A more in-depth discussion is provided in the “Terminology” section attached hereto as Exhibit A.
The hammock concept has been adapted to produce a small number of true hammock devices serving as seats. Any hammock may be sat in by positioning the user's body crosswise to its length, but ergonomics, space requirements and style have compelled a few design improvements.
The Caribbean hammock chair is a ubiquitous design, the seat portion being formed of a downsized Mayan Style hammock, in which the user sits crosswise. The two attachment points of this deeply hanging sling are then connected to each end of one sizable overhead spreader, which is then suspended, via tethers, to one single overhead anchor point. The seating sling may be asymmetrically proportioned to provide a more chair-like shape for improved looks and ergonomics.
A variation of the Caribbean hammock chair employs the same general sling configuration and crosswise upper spreader with one overhead anchor point, but the hammock sling is somewhat smaller and is provided with additional front-to-back spreaders at either side of the user's seat, thus providing more structure to the seat bucket.
RELATED ARTA number of modern variations and developments have sprung forth in recent years as the popularity of hammocks has surged in the recreational field. A number of specific examples of modern hammock variations will be discussed below.
The basic Mayan Style has been produced in vast numbers using modern nylon or polyester taffeta fabrics and are commonly referred to as “bunched” or “gathered end” hammocks for the way the fabric is attached to the suspension points.
Both Mayan Style and Bridge Style hammocks have been augmented with features to improve their usefulness for outdoor camping, including integrated bug resistant net enclosures, water repellant rain flies, and built in utility pockets. At least one example has been adapted to provide a reclining surface with ergonomics similar to that of a chaise lounge.
Another variation is the combination of a sleeping bag with integrated hammock structure so that it can be suspended in the manner of the navy hammocks while the occupant enjoys the thermal protection of the sleeping bag.
Several examples have been developed to be multi-purpose, and these more closely resemble ground based tents that have been adapted for suspension than a traditional hammock. Of these, some are distinguished by the intended flatness of their floors and the high tension of the suspension system required to maintain that characteristic. An example of this is the Tentsile™, a convertible hammock device utilizing three high tension suspension lines radiating at equi-angles from the center. Its body is comprised of the suspension lines under tension at its periphery supporting an equilateral triangular trampoline-like floor, which is taught and ideally flat, but necessarily sags a little in use. A purpose-built dome style tent can be fitted over the trampoline portion.
The Treble™ can be seen as a hybrid between a trampoline and bridge hammock, with the shape of an elongated isosceles triangle. Utilizing three anchor points, two lines proceed laterally from the head end to provide lift and spread, while a third from the foot to complete the suspension system. Load bearing lines on the periphery have their curvature predominately in the horizontal plane and support a fabric bed portion, cut to be shallow with a gentle sag, and thus provide a measure of body conforming. It includes adaptations for placing one's feet on the ground in a more seated posture. A separate, but attachable tent fixture with lofting poles is also available.
The Sky Chair™, derived from the Caribbean chair, employs the same general sling configuration and crosswise upper spreader with one overhead anchor point, but the hammock sling is somewhat smaller and is provided with additional front-to-back spreaders at either side of the user's seat, thus providing more structure to the seat bucket. Some examples also include a footrest comprised of its own mini sling and spreader, suspended by its own tether connected to the central overhead anchor point.
The Clark Jungle Hammock™ and The Crua Hybrid™ take the form of a pup tent or bivvy bag with riser poles arcing from side to side at head and foot to loft the tent portion. This is then integrated with a bunched end hammock in the case of the former, and a spreader style leisure hammock in the latter. In the latter the user lies parallel to the suspension lines, and the overall proportions are tapered a little from head to toe.
The Exped Ergo™ and an improved version, the Amok Draumr™, fall within the category of 90° hammocks. These examples bear similarity to the Caribbean chair in that they are hung with a deep sag and the user's body is positioned fully perpendicular to a line between the anchor points, but they differ in that the ends of the sling are attached directly to two separate anchor points, rather than an overhead spreader. The seat or bed portion is traditionally connected to these suspension points by lashings distributed along the length of each side, but the Draumr™ replaces these lashings with triangular fabric panels, and partially relies on the bulk of an air mattress to assist with lengthwise spread and flatness of the bed surface. In addition, the Draumr™ can be adjusted from a fully flatbed form to a lounging chair form. These examples are adapted for wilderness camping with integrated bug net and rain flies.
The NEMO Cloudview™ is a light-weight Bridge Style hammock suitable mostly for daytime leisure reclining and socializing. It is cut to maintain the user in a more upright reclining position for better visibility and exposure to their surroundings, with their head and shoulders above the top edge of the low point in the fabric bed portion. A portion of the side panels are composed of screen mesh to expand the user's field of view.
The Hydro Hammock™ is a device made of heavy-duty waterproof fabric designed to be filled with water and enjoyed as a hanging bathtub. It has the form of a modern bunched end hammock, but the structure of a bridge hammock, in that two heavy duty suspension lines support the lateral edges of the tub, while smaller lines bunch the ends. There are no spreaders, as the water and user's body accomplish this. A portable heating station with pumps and hoses circulates and heats the water for comfort.
The Hangover chair is hybrid between a suspended cot chair and true hammock, with the seat portion being formed of a thick cushion over a fabric panel whose front edge is supported by a horizontal rod and back edge is suspended by the fabric seat back, which resembles half of a bunched end hammock. Both ends are suspended by tethers to a fore and aft spreader overhead, which is in turn suspended from an overhead anchor point.
The design and construction techniques of bridge hammocks are well known in the art. An example of a conventional bridge hammock is pictured in
An occupant (not shown) will be supported and contained within the fabric body of this hammock device, typically in a supine position. The hammock body 20 is constructed of one or more pieces of Ripstop™ nylon, or some other flexible membrane forming the body trough or cradle, the central component of the device. This may be fitted with optional end panels 22 to provide a more complete enclosure.
The upper edges of the body trough are attached to the suspension lines 24 found at either side of the hammock—these being composed of polyester webbing, rope, or other suitable line material. In use, the weight of the user is supported by tension in the fabric body as it passes from side to side under the user, thus transferring forces laterally and upward to the suspension lines.
As the suspension lines traverse from end to end of the bed trough, they assume a characteristic curve in response to the load placed upon them. The upper edge of the side walls of the body trough are cut to accommodate this characteristic curve. The suspension lines are typically held apart by spreaders 26 positioned at either end of the hammock. which are retained on the suspension lines by a suitable fastening means. A suitable distance beyond the spreaders, the suspension lines are joined together at the ends of the hammock itself, forming the apex 30 of a triangle, where an integrated attachment loop 32 is frequently provided.
The hammock as a whole is suspended above the ground via attachment to two elevated anchors 40. In many deployment settings, anchor extension lines 42 are used to convey the tension from the anchors to the hammock itself. In traditional usage, the anchor points employed are of similar elevation, resulting in a generally level bridge hammock bed, thus having a suspension system with negligible collective slope.
SUMMARYThe present invention may be embodied as a bridge hammock system for suspending at least one load between first and second anchor points, the bridge hammock system comprising a suspension system and a load bearing sling. The suspension system comprises at least one suspension line and defining a first end adapted to be connected to the first anchor point and a second end adapted to be connected to the second anchor point. The load bearing sling has at least one load support surface region and at least one side panel region. The suspension system defines a curve such that the first end of the suspension system defines a first slope and the second end of the suspension system defines a second slope. The at least one side panel region supports the at least one load support surface region from the suspension system. The at least one side panel region is sized and shaped to integrate the curve of the suspension system with the load bearing surface region such that a collective slope of the suspension system is greater than zero, tension forces on the first end of the suspension system are substantially upwardly directed, and tension forces on the second end of the suspension system are at least one of substantially laterally and substantially downwardly directed. The at least one load is arranged on the at least one load support surface region.
In a bridge hammock system of the invention, the desired shape and orientation of the at least one load support surface region may be adapted to support a human occupant in a generally horizontal orientation. A desired shape and orientation of the at least one load support surface portion may be adapted to support a human occupant in a sitting or reclining posture. A bridge hammock system of the invention may further comprise at least one spreader configured to engage the suspension system or, alternatively, a plurality of spreaders configured to engage the suspension system. At least one rigid member may be used to define the at least one load support surface portion. The suspension system may comprise a single suspension line configured and arranged to support the at least one side panel region to suspend the at least one load bearing surface portion from the single suspension line. A soft spreader may be employed to engage at least a portion of the load bearing sling. The collective slope of the suspension system of a bridge hammock system of the present invention may be greater than approximately 10 degrees.
A bridge hammock system of the present invention may be configured to operate in a hammock mode and in a tent mode. In the hammock mode, at least a portion of the load bearing sling is suspended above the ground such that the load is supported above the ground. In the tent mode, at least a portion of the load bearing sling is arranged to define a shelter for a person sitting on the ground. When the hammock system operates in the tent mode, a first portion of the load bearing sling adjacent to the first end of the suspension system is higher and wider than a second portion of the load bearing sling adjacent to the second end of the suspension system.
A bridge hammock system of the present inventio may further comprises at least a first elongate member and a second elongate member, where the first and second elongate members are configured in a first mode in which the first and second elongate members are separately arranged to engage the suspension system and a second mode in which the first elongate member is connected to the second elongate member to form a riser pole having an effective length that is greater than lengths of either of the first and second elongate members.
The present invention may also be embodied as a method for suspending at least one load between at least first and second anchor points, the method comprising the following steps. A suspension system comprising at least one suspension line and defining a first end and a second end is provided. The first end is connected to the first anchor point, and the second end is connected to the second anchor point. A load bearing sling having at least one load support surface region and at least one side panel region is provided. The load bearing sling is operatively connected to the suspension system such that the suspension system defines a curve and the at least one side panel region supports the at least one load support surface region from the suspension system. The first end of the suspension system defines a first slope and the second end of the suspension system defines a second slope. The at least one side panel region is sized and shaped to integrate the curve of the suspension system with the load bearing surface region such that the load bearing surface region defines a desired position and orientation of the load, a collective slope of the suspension system is greater than zero, tension forces on the upper attachment portion are substantially upwardly directed, and tension forces on the lower attachment portion are at least one of substantially laterally and substantially downwardly directed. The at least one load is arranged on the at least one load support surface region at a position below the first anchor point and above the second anchor point.
The present invention may also be embodied as a bridge hammock system for suspending at least one load from two or more anchor points, the hammock system comprising a suspension system and a load bearing sling. The suspension system comprises at least one suspension line and defining a first end adapted to be connected to the first anchor point and a second end adapted to be connected to the second anchor point. The load bearing sling has a plurality of load support surface regions and at least one side panel region. The suspension system defines a curve such that the first end of the suspension system defines a first slope and the second end of the suspension system defines a second slope. The at least one side panel region supports the at least one load support surface region from the suspension system. The at least one side panel region is sized and shaped to integrate the curve of the suspension system with the load bearing surface region such that a collective slope of the suspension system is greater than zero, tension forces on the first end of the suspension system are substantially upwardly directed, and tension forces on the second end of the suspension system are at least one of substantially laterally and substantially downwardly directed. The at least one load is arranged on the at least one of the plurality of load support surface regions. In this configuration, the bridge hammock system can be configured such that at least one of the plurality of load supporting surface regions is configured to support an animal and/or a plant.
The invention disclosed comprises a variety of sloping bridge hammocks, where the designs benefit from an engineering method put forth primarily to establish the shapes of the suspension systems, but also to aid in planning other features of the device.
Generally speaking, a bridge style hammock of the present invention is configured to be suspended between two anchors, where the suspension system is designed to have a substantial collective slope. The device is proportioned such that the curve of the suspension lines slopes significantly upward at one end and slopes very little or downward at the other, allowing the use of anchor points with significantly different elevations. The load supporting surfaces are positioned and suspended by the side panels of the sling in that the side panels integrate the shape, elevation and posture of the load support surface with the curve and slope of the suspension lines.
The present invention may be embodied in a number of different forms, a number of which will be generally described in this Introduction section.
In one form, the present invention may be configured as a bed. In this embodiment, the bridge hammock of the present invention is embodied as a sloping bridge hammock that includes a sling portion adapted as a bed to support a human occupant in a generally horizontal, supine position for sleeping. In another form, the sloping bridge hammock of the present invention may be embodied as chair comprising a sling is adapted as a seat to provide ergonomic support to an occupant in a sitting or lounging position, with the user's body oriented in line with the length of the hammock.
In another form, the present invention may be embodied as a bridge style hammock having a single, central suspension line and no rigid spreaders. As in other example bridge hammocks of the present invention, the fabric body is comprised of a load supporting surface and shaped side walls that integrate the boundaries of the supporting surface with the curve and slope of the suspension line. Unlike previous bridge hammocks, the side walls join together centrally overhead on that suspension line such that the sling wraps all the way around the load to fully enclose it above and below. The design is enhanced by the asymmetry produced by a steeply sloping suspension system and by the inclusion of a soft spreader on the load support surface.
Other forms of the bridge style hammock of the present invention may be adapted for non-traditional loads. As one example, the bridge style hammock of the present invention may be configured to function as a suspended pet bed that is comfortable, light weight, economical and collapsible. The load support surface of the sling is sized and shaped to best suit the intended occupant. The device may be a single load pocket, or it may be an array of such pockets arranged to form a multi-level pet bunk bed. As another example, the bridge hammock of the present invention may be configured to function as a planter that is light weight, economical and collapsible. The planter device may be a single load bearing pouch to contain potting soil and plants, or it may be an array of such pouches variously proportioned to form a tiered planter. The planter device may be constructed in a wide variety of ways—it may use two, three, or more anchors, such that the ends of the suspension lines may be individually affixed to solid surfaces, or alternatively, they may be held apart by spreaders, and then join to common apex and vertex points, which may then be suspended by individual anchors.
Yet other forms of bridge style hammocks of the present invention may be adapted as asymmetric two-anchor examples. Of the two-anchor examples, and especially those used as camping hammock tents, utility is found in an example exhibiting marked asymmetry and adaptions for alternate uses. A bridge hammock is asymmetrically proportioned such that it is significantly larger and taller at the head end than the foot end, such that a person may sit upright inside. This may also enable entry and exit through the end of the hammock body.
The equipment is adapted to allow the lateral spreaders, used between the suspension lines when the hammock is suspended, to be repositioned to serve as a lofting pole when the device is deployed on the ground as a ridge tent.
Additionally, the proportions of the device facilitate adaptations for climbing up and entering through the end of the hammock when it is suspended high above the ground.
II. ExamplesThe following sections disclose specific embodiments of the Invention implementing the general principles discussed herein.
A. Bridge Hammock Bed with Substantial SlopeThe common lay-down hammock bed is the most easily recognized and understood configuration of the bridge hammock family and typifies the use of this invention. This example bridge hammock system is a bridge style hammock bed with a substantially non-zero collective slope, the example bridge hammock being designed and proportioned such that the curve of the suspension lines slopes significantly upward at one end and generally horizontal or downward at the other, allowing the use of anchor points having significantly different elevations.
The term “collective slope” as used herein refers to an average of the slopes, defined in a vertical plane, of one or more suspension lines included in a hammock system. In a given system, each suspension line will have a characteristic curve defined by the deflection needed to resist the load forces placed on it, such that the line will have a first end with a first slope, a second end with a second slope, and a intermediate length adjoining the two ends and exhibiting a transition from the first slope to the second slope.
The slope values can be determined geometrically, where slope in the line is measured as the rise over run in a specific portion of the line, or as the tangent of the angle measured from the horizontal to a specific portion of the line. The values used to calculate collective slope are taken by proceeding from one end of the line to the other. The value can also be derived mathematically, or prescribed by the designer, as the linear coefficient from the first constant of integration when a function describing the mass distribution of the load in the hammock is integrated twice to obtain the shape of the suspension lines. Each anchoring extension line attached to a suspension line will exhibit the same slope found at the end of the suspension lines to which it is attached.
In a hammock system with multiple suspension lines, the collective slope of the system is the average of the collective slopes of the individual lines. Every hammock has a collective slope, even if the value is zero. Traditional hammocks are hung to be level, with opposing anchors at the same elevation, such that the slopes of either end of the device are generally equal and opposite and thus cancel each other out. As such, the concept of collective slope is typically not relevant with conventional hammock systems.
To many, hammocking is about freedom, simplicity, and convenience—the freedom to rest or sleep in whatever location they deem pleasant, regardless of ground surface conditions; the simplicity of a small amount of gear meeting their bedding needs; and the convenience of minimal effort required for setup.
The inherent design of hammocks current in the art presents certain frustrating challenges that detract from that freedom and simplicity.
For a standard hammock, two anchor points are spaced appropriately for the type of hammock and lines in use, and these must allow tie-in at the right height on both ends for a level hang. Additionally, the anchor points must be strong enough to resist the potentially high-tension forces involved. Lastly, we would like the space around and below the hammock to have a desirable landscape.
In practice, there may be plenty of trees or other features in the area, but the spacing may be unusable, or there may be obstructions like brush, branches or rock ledges in the way of setting the hammock between the ones that are appropriately spaced. The ground below may be unfit to conveniently approach the hammock for entry and exit. This limits the choice of locations where a hammock may be successfully deployed.
In addition, adjustment of the suspension system can be a challenge due to the relationship between the intended elevation of the hammock body, the relative distance and elevation of anchor points and the required length and angle of extension lines to connect them. Coordinating these factors increases the time it takes to set up a hammock and contributes to user frustration.
One objective for this example bridge hammock system is a hammock that is easier to set up, usable in more locations, and provides many other benefits as well.
The invention disclosed is a bridge style hammock device with a suspension system having a substantially non-zero collective slope. In this embodiment, a sling portion is shaped and proportioned such that bottom surfaces support a human occupant in a generally horizontal, supine position, with those bottom surfaces being positioned and suspended by the side panels or portions of the sling, whereby the side panels integrate the shape, elevation and posture of the bed portion with the curve and slope of the suspension lines.
A bridge hammock with a significantly sloping suspension system needs only one elevated anchor point, rendering the device useful in many more locations. Once an elevated anchor is established for the upper end of the device, the opposite end may be anchored to a point that is low, or even at ground level. Anchors of this type are much more readily available, making the device useful in many more environmental settings, a valuable characteristic when used for adventure camping. If a second anchor is not present, a low or ground-based anchor may be improvised or constructed with much greater ease than a high anchor. For example, a dead-man anchor installed in snow or sand, or a strategically positioned motorcycle kickstand may serve the purpose. In addition, the greater ease of providing a low anchor frequently makes it possible to place the device in other positions radiating from the one high point, rather than the restricted line between two such high points.
A sloping bridge hammock facilitates set-up and adjustment of the suspension system. An example may be designed with an upper extension line which is intended to be short and set at a familiar angle that is easy to visualize, while the lower line is set at the horizontal, where it may be extended any distance without effect on the set of the hammock.
The concept of sloping bridge hammock design provides other benefits as well. As elucidated in previous sections, the extension lines may be any combination of angles that suitably suspend the load, giving the designer a great deal of flexibility to create a product best suited for its intended purpose. The insight that the load-bearing surfaces of the body pocket are functionally separate from the shape of the suspension curve allows the production of a device which offers the user a completely flat lay, or any other desired posture. The asymmetrical hammock design inherent in the sloping suspension allows a more useful distribution of internal space, while the lower cut at the “foot” end allows easier ingress and egress of a lofted hammock and provides better visibility for enjoying the view or socializing. Lastly, the asymmetry may be employed to produce more interesting, aesthetically pleasing shapes.
The example shown in
The example in
The design objectives for this hammock example are that it has an aesthetically pleasing shape and provide a lay-flat posture for comfortable overnight occupancy, including side sleeping. The size and proportions will allow the user to store some gear inside and sit up to perform limited activities, as well as render the hammock tent suitable for ground pitching. In keeping, this example may be adapted to include an integrated bug net and rain fly, with sizing and material selection yielding medium-light construction for backpackers, and package features to support quick, convenient set-up and take down.
Design of the Suspension System includes that the device be suspended between two anchors that are horizontally opposed and offset in elevation. Two suspension lines are joined at the extremities of the device, held apart at the head end by one, large rigid spreader. Discrete attachment loops are provided at the apex and vertex of the device to facilitate connection and prevent any shifting of the same along the suspension lines.
The terminal angles of the suspension system are chosen as a suitable compromise between several factors, including how they cooperate with the desired proportions and shape of the load sling. The head end of the suspension lines angles upwards at 45 degrees, intended to be easy for users to recognize during set-up, while allowing the anchor to be within reach from the ground if anchor extension lines are limited in length.
This angle generates only modest horizontal tension, approximately equivalent to the weight of the load, permitting the use of anchors for the lower end that may be tender, but are most readily available, such as shrubs, rocks or a stake in the ground. The lower end of the suspension lines angles downwards from the device at 5 degrees as a compromise between horizontal and slightly declined, as a horizontal line is easiest for setup and would add no additional tension, but a declining line allows for ground-based anchors, with a modest contribution to horizontal tension. These values give us a deflection of 40° and a collective slope of −0.544 when accounted as the direction from the upper anchor to the lower.
The inclusion of a full-length structural ridgeline (not shown) would allow the lower anchor extension line to be drawn more steeply downwards, and result in the upper extension line being drawn to a shallower angle, but also generate greater tension. It is expected that in variable outdoor settings the user will employ a relatively short upper anchor extension line and a longer lower extension line.
The shape of the suspension line curve has a vertical component which is generated by taking the second integral of the mass distribution equation shown in the Figures. Vertical tension force from the weight of the load is the only factor contributing to this component of the shape. The lateral component of the curve is derived as an approximation. Lateral deflection is ignored between the apex and spreader, where there is relatively higher tension in the suspension line, a reduced load, and the side walls of the sling are closer to vertical. Between the spreader and the vertex, deflection is approximated using the same second integral of the mass distribution, but with different angles and offset, which are selected by visually matching the required shape, or aspect ratio, between the width of the spreader and length to the vertex. A starting angle of 34° at the spreader and ending angle of −8° at the vertex yields a tension coefficient of 1.9 and a slope for the curve of −0.41, which can be used in the equation for the shape coordinates.
One collapsible light weight spreader holds the suspension lines apart and is positioned approximately over the shoulders of the user to maximize usable volume around the arms and minimize shoulder squeeze. A length for the spreader of approximately 1.2 m is a compromise between maximizing the above factors, and weight of the package.
The device may be fitted with an optional ridgeline (not shown) from the apex to the vertex, setting the length of the curve, thus allowing greater variability in the angles of anchor extension lines, and also serving to hold up a rain fly.
The hammock sling includes a load pocket designed for a human body laying flat and completely at rest, with a shape and dimensions derived according to the following considerations:
The body of the hammock is asymmetrically proportioned in width and depth from end to end. There is a height difference of about 1.3 m between the apex of the suspension and the level of user's body, giving the bed trough a depth and volume sufficient for the user to store some gear, sit up, and perform limited activities inside, even with a bug net enclosing the top.
Side walls at the foot box are tall enough to contain the user's feet and compact bedding. The supporting surface is sized to comfortably accommodate an average physically fit North American male of about 1.8 m height and has a tapered width profile approximating the shape of the user lying on their back.
The elevation contour of the surface is generally flat, with a modest central droop of a few centimeters along its length to enhance comfort. The side-to-side depth contour is given an elliptical cross section, with eccentricity varying along the length to best reflect body geometry in each section. The length of the support surface is extended beyond the body of the user at each end.
At the head, space is provided to include a pillow and reduce direct bodily contact with the end panel. This also gives more volume above the bed level, which can be used for gear storage in optional add-on pockets—not shown, but common in the art. At the foot, rather than including a discreet end panel, the sling geometry is merely extended to the vertex, providing more gear storage and accommodating an integrated stuff sack and privacy enclosure (not shown in 3.) The length of the extension is prescribed, at the time of suspension system design, to provide the desired width of the suspension and sling at the foot box, which in this example places the vertex 3 m horizontally from the apex.
The shaped side panels serve a structural role along the majority their length, joining the generally flat body support surface with the curving and sloped suspension lines to suspend the load. The side panels also provide privacy and act as a barrier against nature's elements.
Auxiliary features include a panel at the head end of the device, containing the user's gear and providing privacy and protection against nature's elements. While not shown, the design is suitable for the inclusion of an integrated stuff sack at the foot end of the device. Also not shown, a double bottom sleeve may be included on the outside of the load bearing sling for the optional insertion of light duty insulation.
The configuration of tension forces within this hammock bed is relatively simple, such that the shape design easily accommodates the requirements for structural performance. During primary use of the device, with the user stretched out flat in position, tension forces in the sling are oriented almost entirely crosswise of the device, originating with the load and being directed laterally, then vertically upward in a parallel array within the shaped side panels, from the bed panel to the suspension lines. This configuration indicates that the grain of the fabric sling simply be oriented crosswise of the length of the device. In this use, the head end panel and smaller part of vertex bear insignificant loads. During secondary use, when the user may sit up in the middle or sit at the head end and lean against the head panel, distribution of the load will be altered. The suspension line curvature will deform from its normal shape, allowing the sling to sag more beneath them. Diagonal tension may be generated within the sling from the area where the user's back rests on the end panel to regions on the suspension lines farther along the device, but neither effect will be detrimental to overall performance.
The fabric pattern for this example is depicted in
The spreader is constructed of tubular aircraft aluminum and is adapted to be disassembled into three pieces. The ends of the spreader are maintained inboard of the webbing for aesthetics and to prevent potential damage to a rain fly. In a novel design, a receiver for the tubular spreader is provided in an engineered plastic part having a circular slot as a socket in a load-bearing base which is fastened with screws to the webbing, which itself is locally reinforced with ballistic nylon fabric.
The main body of the sling, comprised of the load support surface, or bed panel, and both side panels, is a simple trough shape that can be formed from a single flat piece of material. However, stock materials of the types used are typically not available in the dimensions required for the whole piece, so multiple pieces must be joined.
One paneling scheme may orient the stock material along the length of the sling, utilizing separate pieces for the bed panel and each side panel, and then joining them with seams along their mutual boundaries, running lengthwise of the device.
The preferred scheme orients the stock material crosswise from side to side, resulting in fewer pieces and less seaming. More significantly, the midfield seam is then oriented parallel to the greatest tension forces and bears little load, making it is less likely to suffer structural failure. Although the seam crosses the bed panel, where it's lesser stretch interrupts to soft surface, it may be conveniently positioned midway along the length from head to foot, under the thighs of user where its presence isn't noticed. In either case, the orientation of tension forces in the sling calls for the fabric grain to be parallel or perpendicular to the centerline of the device, as the warp and weft of this fabric are nearly symmetrical. A diagonal orientation on load bearing portions would allow excessive deformation. In addition, the head panel and the optional top panel of an integrated stuff sack (not shown) are added as separate pieces.
Dimensions for the sling pattern are generated by taking a series of vertical cross sections at intervals along its length. The path lengths of these sections are used to generate a parallel array of dimensions for the width of the pattern piece, arranged with their midpoints on the centerline. While the 3D cross sections of the sling are parallel, the inward cant of the suspension lines above the spreader generates polygons that are wider at the top than the bottom, resulting in a non-parallel arrangement of the flattened array for that portion of the sling. The length of the suspension lines above the spreader is found using standard trigonometry with the prescribed angles and offset between the apex and the spreader. The length of the line below the spreader is found as a sum of the distances between data points on the suspension line curve as it was calculated to support the load.
In the following discussion of the illustrated examples, certain reference characters will be used in connection with components of the examples of a common type. For example, each of the examples of a bridge hammock system of the present invention comprises a body and one or more suspension lines. The reference character “200” will be used to refer to the body and reference characters “121” and “122” will be used to refer to first and second suspension lines, respectively. As will be described below, the body 200 and suspension lines 121 and/or 122 may be configured differently depending on the particular example bridge hammock system being described.
Referring back to
The suspension lines 121,122 span from the central portion of the hammock end wards, to where they join together at the upper extent, or apex 131, and lower extent, or vertex 132 of the hammock, where they may be fashioned to include upper and lower attachment loops 133 and 134.
A horizontal rigid spreader 151 (seen in end view), is positioned between the suspension lines near the head end to provide lateral spread. A smaller rigid spreader 152 may, likewise, be included and positioned near the foot end for the same purpose.
Anchor extension lines 111,112 extend from the upper connection to an upper anchor 101, and from the lower connection to a lower anchor 102 respectively. In use, tension generated by the weight of the user resting on the bottom panel is transmitted vertically by the side panels to the suspension lines above, where static equilibrium causes horizontal tension forces to be generated within the suspension lines extending between anchor points, thus suspending the load.
The diagram portrays that the anchors may be at considerably different elevations in relation to the hammock body, and that the starting and ending slopes of suspension the lines are a product of the positions of the anchors and allowed slack in the suspension lines. It portrays that the weight of load is distributed along a span of the hammock, and that the suspension lines curve as they provide distributed support along the length of load. It indicates how this curve is characteristic of the design of the hammock, incorporating the slope of the suspension system as a whole, and that this collective slope is greater than 0 and typically much greater than 0. In particular, the collective slope of the suspension system is typically, but not necessarily, within a first range of greater than approximately 10 degrees.
The diagram also elucidates that new concept allows considerable variation in positions of various anchors and their uses. It portrays how the upper edges of side panels are shaped to accommodate the curve in the suspension lines, and that the orientation of the load is independent of the shape or slope of those suspension lines, and that the orientation of the load is dependent on shape and design of load bearing portion of body pocket.
The hammock body 200 is constructed of one or more pieces of fabric, and is generally comprised of a bottom panel 213, suspended between left and right-side panels 201,202, and may incorporate an end panel 215 affixed across the head end of the bed trough. The upper edges of the side panels are attached to left and right suspension lines 121,122 on either side of the hammock.
The suspension lines span from the upper extent of the hammock device, where they join to form the apex 131, along the length of the hammock to the lower extent, where they join to form the vertex 132. The webbing beyond these joints may be formed into integrated attachment loops 133,134, representing the extremities of the device. Spread is provided by a three-piece collapsible spreader 150 positioned between the suspension lines at the larger end of the hammock and is retained there by spreader fastening means at each end 155 (not illustrated).
The hammock example depicted demonstrates that the suspension lines at the upper end the device are oriented at a substantially upward angle to cooperate with an elevated anchor, and the suspension lines are oriented at the lower end the device at a nearly horizontal angle to cooperate with a much lower anchor, and the span between the two ends is joined by a curve with a substantially non-zero collective slope. We see that the upper edges of the side panels are cut to accommodate the characteristic curve produced by the deflection of suspension lines under load, and that the shape of the side panels is integral to the structure and performance of the device. We also note that the asymmetrical proportions of hammock body conveniently incorporate the slope of suspension system, and that there is much greater depth and volume available at head end than is seen in comparable prior art bridge hammocks. Also, while the length of the largest spreader determines the overall width of device, it can be inferred that the optional inclusion of additional spreaders (not shown), would not alter the general slope or function of the device.
The pattern is an arrangement of a left side panel 201, a right side panel 202 and a central bed panel 213, whose approximate boundaries are indicated by dashed lines. An optional head end panel 215 is shown as a separate piece. The main pattern is symmetrical about a centerline (not shown) and extends from the narrowest section at the hammock body vertex 232 to the edge 515 that will form the head end of the body trough. The symmetrical profile includes a bed trough extension 229 with straight edges from the vertex to the stuff sack boundary 570. From that point it is cut with a specific curve 501 to accommodate the characteristic curve and slope of the suspension system as it supports the load in the bed trough. The curve is markedly interrupted, changing direction at a corner in the profile 551, accommodating the lateral deflection of the suspension line by the main spreader. The pattern terminates with the head-end boundary 515 of the bed trough, where the optional head end panel may be attached.
The body trough extension will become the Integrated Stuff Sack, having dimensions that are tapered towards the vertex, which will form a closing geometry of the hammock sling.
The bed panel is sized and shaped to accommodate the body profile of a typical male outdoor enthusiast laying supine, such that the lateral dimensions of the flat pattern account for a semi-elliptical cross-section of the body trough, approximating the bottom surface of the user.
The side panels are shaped to join the bottom panel to the suspension lines. Each portion is dimensioned to span the distance in three-dimensional space between the respective positions of the lateral boundaries of the bottom panel and the compound curves of the suspension lines.
Included in
In practice, the pattern will have suitable margins added to accommodate seams—along the left and right lateral profiles to where the fabric may be wrapped around and stitched to the suspension line webbing, and at the head end to attach to the head panel, and at the foot end to finish the product. The top panel of the optional integrated stuff sack is not shown.
The pattern shown represents merely one end product of the implementation of the invention and is not definitive of the invention itself. This pattern serves the particular example shown in
The bridge-style hammock device of this disclosure, having a steep collective slope, is adapted to provide ergonomic support to an occupant in a sitting or lounging position, with their body oriented in line with the length of the hammock.
It is natural that the hammock concept, so widely adopted for lounging and sleeping, would also be employed for sitting upright. While it's possible to sit in any general-purpose hammock, the ergonomics of sitting are more complex and demanding than for lying down, so specialized adaptations are needed. The prior art provides a very limited number of unique configurations for sitting, and in spite of the strong demand for the commodity, little innovation has occurred. This invention provides a new class of hammock device, utilizing the flexibility of the bridge hammock concept and the advantages of the steeply sloping suspension system to provide a completely new example of hanging seat.
More specifically, the most primitive example of a purpose-built hammock seat is merely a bunched end hammock of a reduced size, whereby the user sits in a small sling, and if in-line with the axis, may lean back in it also. As described in the Background section, the most ubiquitous and distinct configurations for sitting are the Caribbean chair, a sling with a single overhead spreader, and a modern derivative, the Sky Chair™. Also, there are a very limited number of 90-degree hammock beds that can be adapted for sitting, as exampled by the Amok Draumr. Additionally, there are a few isolated experimental examples in published material resembling small bridge hammocks with a modified body pocket, where the user's body is in-line with the suspension.
These examples all suffer from shortcomings in their desirability and usefulness. Finding suitable anchor points is a fundamental challenge for all examples. Most types of hammock device used for sitting require two elevated anchor points—this includes any Mayan style or standard bridge hammock beds, the reduced size bunched end hammock seat, the 90-degree hammocks like the Draumr in lounge configurations, and most of the experimental hammock chairs seen. These anchors must be robust, of approximately equal elevation and appropriately spaced to work for the example in question. The other configurations, including the Caribbean chair and Sky Chair™, require one anchor point directly overhead. These must be strong enough and high enough, yet accessible, and also have a large enough radius of free space directly beneath them to accommodate the width of the chair and any swinging action to take place. In all cases, it is preferred that there also be desirable landscape in the space below the hammock or chair. Anchor points meeting all the requirements for any given configuration are frequently not available.
Poor ergonomics plague the majority of previous hammock chair examples. Beginning with simply sitting in any traditional hammock bed (as a reference), we note that if the user is in-line with the device, they are unable to lower their feet below their seat level, which can be awkward and requires certain internal strain to maintain balance and an erect posture. If they turn to sit cross-wise to the axis of the device, they may drop their feet over the side, but then the edge of the hammock sling, being under significant tension, presents a hard, uncomfortable edge to the underside of their thighs. This same effect occurs in some chair examples, including the mini bunched-end hammocks and certain boson's chair or bucket seat designs.
Most existing hammock chairs are unable to provide a properly supported, upright, forward facing posture—a little recognized, but significant shortcoming. This is a posture one would adopt for eating or other activities, with articles held in front of, rather than above the user, and typically with feet resting on the ground for added stability. In this posture, the seat and thighs are nearly level, such that supporting forces from the sling are predominantly vertical, and the back is generally upright with a modest lean, with supporting forces being more horizontal. A fore and aft pendulum configuration is created in examples using a single overhead anchor, like the Caribbean chair or the Sky Chair, or two laterally disposed anchors like those used by any 90° hammock beds converted for sitting.
Equilibrium requires forward and rearward force components to balance, and for the center of mass of the user to swing to a point directly below the axis of rotation. All tension forces within the sling will ultimately be directed upwards towards the axis in an inward radial pattern. The torso of the user leaning back generates significant horizontal force on the pendulum that can't be counterbalanced by the lesser mass and vertical force of their legs pressing downwards, especially if their feet are supported by the ground. Equilibrium is regained by the entire device rotating about the axis to a point where the mass of the user's torso and the direction of its lever arm are matched by the opposing mass, direction and lever arm of their lower extremities, resulting in a posture that is no longer upright. If the designer shifts the placement of the axis to be over the center of mass in the desired posture, the forward parts of the resulting sling geometry cannot be supported by the available tension, with its radial pattern directed upwards and backwards, so the sling will collapse.
Good seating posture for long term comfort will exhibit a relatively flat back surface, rather than slumped into a curve, with the upper and lower back being generally aligned. Unfortunately, most existing hammock chair examples lack the ability to provide the low back support needed for this. This is first encountered by sitting in any regular hammock bed (as a reference), either in-line or crosswise, since the sling has no definition or contouring to provide that support, and a seated person must slump forward into a curve in order to remain upright. In examples intended for sitting, like the mini-bunched end hammock or larger examples tilted upwards, and even slings of some lawn chairs—the simple nature of the sling passing lengthwise under the torso of the user cannot provide the localized pressure needed in the low back area. In hammock seats with a crosswise axis like the Caribbean chair, the structure is different, providing crosswise tension and appearing to allow localized support at the low back area. However, the tension forces needed to generate adequate pressure must come from forward of the user, but this is not available, as described above.
Some hammock seats like the Sky Chair™ do provide more shaped ergonomic support. However, this is accomplished by the additional structure, including spreaders and tension members, rendering them more complex, costly, bigger, bulkier and heavier, making the product less suitable for those needing a light, compact and economical furnishing.
Accordingly, one objective for this hammock device is to provide a suspended seat that is ergonomically correct, has the least demanding anchoring requirements for suspension, and can be light weight and compact when stowed.
The following embodiment and invention is a bridge style hammock device with a suspension system having a substantially non-zero collective slope, and a sling portion shaped and proportioned such that supporting surfaces contain and uphold a human occupant in a generally upright, seated posture, with those supporting surfaces being positioned and suspended by the side panels or portions of the sling, such that those panels integrate the shape and posture of the seat portion with the curve and slope of the suspension lines.
The characteristics of the device meet the above objectives and provide other benefits. The device is suspended between two horizontally separated anchors, and with the sloping suspension previously disclosed, requires only one elevated anchor, with the second anchor being served by a point that is low, or even at ground level, and of a kind that may be improvised if needed. The seat pocket overshadows a space between the anchors, being laterally offset from the higher anchor, rather than directly below it. Together, these features render the device useful in more common environmental settings than the prior art.
The bridge hammock structure takes advantage of the principle that the suspension system is separate from the operation of the support surfaces in the seat pocket. A spectrum of user experiences may be created, as the flexibility of design inherent in the shaped side panels allows broad variability of the seat pockets, which may take many forms and be of any posture, from completely laid back to bolt upright, and anything in between.
The fore and aft configuration of the suspension system provides for customizable support distributed along the length of the device. With variable spread, this allows the designer freedom to create suspended seats that are uniquely contoured in 3D space, well supported, comfortable and ergonomically correct with any desired degree of back support or body shape. Some examples can be structurally very simple, comprised of only suspension lines and a sling, or having only one rigid spreader. These may be formed of modern materials that are light and compact when called for, making them highly suitable for packing and transport.
As earlier stated, a broad spectrum of design variation is available. The hammock device of this invention is unconstrained in its form, having a supporting surface whose form is independent of the suspending means, allowing a great deal of variation in configuration—in size, depth, posture, number and placement of anchors, slope of suspension, number and types of spreaders—for example, opening the door to designs that are suitable and convenient for a wide variety of recreational and utilitarian needs. For the same reason, the device is amenable to considerable variation in material selection and construction methods, as any of the options described above in the Implementation section may apply to different embodiments, serving varying needs in price, durability, use or manufacturing resources.
And lastly, the hammock chair concept allows considerable variation of stylistic rendering. The sloping suspension system conveniently accommodates the necessary shape of the seat pocket, facilitating functional designs that incorporate pleasing shapes, diversified proportions and artful appointments to create examples that provide intrigue and appeal to different market segments, thus providing substantial market potential.
The example shown in
The intended use of the device is for a person to be seated comfortably in a reclined posture for complete relaxation, but still upright enough to interact with circumstances before them or carry out activities like read or eat.
The example can be constructed of materials that render it light weight and compact when stowed, thus making it suitable and convenient to pack up and carry, appealing to a broad market of outdoor enthusiasts, day trip picnickers and backyard loungers. A trekking pole could substitute as a spreader, an option appealing to backpackers and hikers who wish to further minimize weight carried.
The design objectives are prioritized to render a lightweight seat that is modestly compact, even if a little snug at the shoulders, of simple construction, easy to pack and set up, and aesthetically pleasing. The basic design is intended to be easily variable for different uses—from ultra-light travel to more durable and permanent.
The design of the suspension system is integral with that of the load sling, or seat pocket, thus they are developed concurrently. The device is suspended between two anchors that are horizontally opposed and significantly offset in elevation.
Two suspension lines are joined at the extremities of the device, held apart at the head end by one rigid spreader. Discrete attachment loops are provided at the apex and vertex of the device to prevent any shifting of the connection with respect to those points.
The terminal angles of the suspension system are chosen to cooperate with the shape and proportions of the load sling. The top end of the suspension lines angles upward 60° from horizontal, being a common angle that is easy to recognize.
The lower end of the suspension lines angles downward at 10°, which takes the anchor line to the ground a short distance in front of the seat and also provides a good match for the shape of the seat. These values give a deflection of 50° and relatively modest horizontal tension factor of less than 1, such that the lower anchor need not be very robust.
In practice, these values will vary by how the user chooses to hang the device, reclining more for greater relaxation or less for carrying on activities. It is expected that in variable outdoor settings users would employ a relatively short upper anchor extension line or none at all, and a modest or short lower extension line.
The shape of the suspension line curve is derived using a Finite Element Method, FEM. Diagonal tension forces interact with the deeply sloping suspension line, altering its trajectory in a manner which, together with the relatively complex load distribution, render the use of a closed form solution impractical.
A map of the forces producing the suspension line shape begins with the distribution of the mass of the load. This is similarly shaped to the curve shown in the
Force vectors are directed approximately normal to seat pocket support surfaces, as seen in an elevation view of the height and length. In addition, these tension forces pull laterally inwards from the suspension lines to the margins of the seat pocket, as seen in a front view. Beginning with the initial conditions indicated above, these forces are summed at discreet points along the suspension lines in a sequence of calculations, determining the new slope for each successive interval. Alternatively, with the aid of suitably adjustable, or iterative, prototypes, the shape of the suspension line curve and seat sling may be determined empirically through a process of trial and error.
One spreader holds the suspension lines apart at the head of the seat pocket. The length of 0.9 m serves the triangular proportions of the device to provide adequate space at the shoulders and knees while keeping the overall size and packaged weight of the device within parameters. The example could be fitted with a second spreader (not shown) positioned on the suspension lines just beyond the foot area, which would allow shortening the length of the vertex somewhat but add complexity and weight.
The Apex angle of 70° forms a triangle with the spreader of a size chosen to balance between minimizing the height of the device and minimizing strain on the spreader connection. A broad, shallow apex angle is shorter, but results in both greater tension in the lines above the spreader and also gross asymmetry of the angles of the line approaching and leaving the spreader. This results in shear forces that compel the spreader to slide down the line, and while the normal compressive force on the spreader end is easily born, the shear strain may require additional structural provision. An internal connection loop is provided by the inclusion of a retainer strap positioned across the apex of the suspension, accomplishing the same purpose as an external loop without adding length to the device. The Vertex is positioned 2.7 m horizontally from the Apex, giving the triangular planform of the suspension and seat pocket an adequate width at the knees.
The load sling of this hammock chair, according to the following parameters, is designed for a human body completely at rest, inclined in a sitting position of approximately 60% upright. The vertical offset between the load and suspension is sized to minimize overall height of the device. The body of the hammock has a depth chosen to position the user's head just below the spreader, free of interference, producing a height difference of about 1.4 m from the center of the user's hips to the apex of the suspension, and the apex approximately 1.7 m above the ground in normal usage.
The significant slope of the suspension lines has the effect that the vertical and horizontal offsets combine to become a diagonal offset between the load pocket and suspension system. The load pocket is given a minimum depth at the top, producing a sling with shallow side-wall angles, which minimizes shoulder squeeze and maximizes clearance for elbows.
The general profile of the seating surfaces, as seen in elevation view, are similar to those shown in
The width and depth contours of the support surfaces are generated using a 3D geometric example approximating a human body. The example is comprised of cylindrical sections on each side bridged together by a flat section, with the diameter of the cylindrical sections and the spacing between them sized according to the physiology represented, such as legs at hip width and shoulders with a flat back section between them. The shape of the support surface and depth contour represent the portion of the user's body that will be in contact with the sling. The lateral boundaries are a governed by the depth of the sling and resulting angle at which the side walls of the sling intersect the body contour.
The geometry of the sling enables the design, with the shaped side panels integrating the contour of the seat support surfaces with the curve of the sloping suspension lines, conveying tension between the two.
While design parameters are prescribed for explicit parts of the seat pocket, once assembled and in use, transitions between the side panels, bottom panel and back panels are indistinct, and in general, all portions of the sling serve overlapping structural functions.
An optional footrest may be provided, as shown, having a rectangular pattern shape and including sleeves at each end through which the suspension lines pass. It may be positioned at varying distances from the seat to match the user's preference, or it may be removed from use altogether if they wish to place their feet on the ground.
The structural performance of the hammock chair is more complex than that of bed examples. Certain proportions of the shape design and configuration of tension forces within this chair example play a significant role in its behavior. The forces producing its behavior include the horizontally distributed weight of the load and conformational forces required to maintain the posture of the load.
A mapping of tension forces in the sidewalls of the sling will indicate a generally radial configuration. Although the design specifies a distinct transition from the angle of the seat bottom to the back support, and pressure forces will generally be normal to those surfaces, the flexible nature of both load and sling allow an averaging effect to take place, such that the direction of tension vectors shows a smooth transition from seat to back. Tension forces from the seat surface are inwardly directed to converge on the suspension lines, where they are generally oriented normal to those lines. Since the center of mass of the user is in the hips and the greatest conformation forces occur at the bend of the hips, a significant concentration of strain occurs near the focal point of the radial pattern.
Conformational forces act to maintain the upright seated posture of the user, pulling the seat back surface forward and seat bottom surface rearward. These forces are directed diagonally inwards from each surface and depending on both the distribution of these forces in the side panels and the position of the suspension line, a portion will intersect and be received by the suspension lines, while the remaining portion will be carried within the side panels of the sling.
The shape of the seat in this example will contain a passive occupant. Unlike in laydown hammock beds, where load forces are mostly vertical, in hammocks examples providing upright postures, there is a risk that the user may slide out. In slings made of slippery fabric, the weight of the user leaning against an inclined seat back tends to slide down. The pliable nature of the sling and suspension allow them to deform to the point where the supportive shape of the seat is abolished, and the occupant is dumped out.
The back support surface is inclined upwards toward the rear at approximately 50°, while the seat bottom is inclined toward the front at 15°. While the angle of the seat area is lesser than the back, the force on the seat is much greater, such that the horizontal force components of each counteract to form a condition of general static equilibrium. This allows the sling to contain a user completely at rest, without any deformation of the sling or tendency for them to slide down and out, a risk found to be significant in slings with slippery material and unbalanced horizontal force components.
The back panel may suffer deformation if the seat pocket is not properly proportioned. While it is the expectation of the design that tension forces in the back panel will be conveyed laterally to the suspension lines, if the dimensions of the shaped side panels above the hip area are too lax, the seat portion will droop below the intended elevation, causing tension to be redirected rearwards and up the back panel, which then deforms. Careful dimensioning of this area is required to effect lateral orientation of tension. Alternatively, tension may be allowed to pass rearwards and up the back panel, with structural support being provided at the top to receive it. This will result in greater pressure on the tailbone area of the user. The use or disuse of the footrest will cause a small change in attitude of the overall device, as the distribution of weight on the suspension lines is altered.
The materials and attachment methods used to construct this example are mostly common in the art. The suspension system is constructed of polyester webbing, its flat profile allowing the fabric of the sling to be neatly wrapped around the webbing and stitched, and the low stretch of the material minimizing deformation under load. The sling may be constructed of a variety of materials, the type selected being suited for the intended use and market. These include ripstop nylon fabric, which is light weight, has a soft hand, mild shear deformation and modest stretch, providing good dimensional stability with the grain and adequate stretch and deformation on the bias to comfortably conform to the user's body.
A spreader is provided for the example shown, being intended for domestic use, and is constructed of solid wood that is attractive as furniture and strong enough to endure significant loads if used as a handle. A second example, suitable for backpackers and travelers, can be fitted with a light-weight collapsible aluminum spreader common in the art (not shown), engineered for reduced weight. A third example, suitable for highly weight conscious backpackers and climbers, can be provided with adaptations of the spreader connections to use a separately provided trekking pole as a spreader (not shown), further minimizing the package weight and size. The ends of the spreader are maintained inboard of the webbing for aesthetic reasons.
A novel design provides a connection for the solid spreader where a modest hole in the end of the solid wood spreader receives a short stud fastened with a screw to the webbing, which is locally reinforced with ballistic nylon fabric. The shoulder of the spreader bears against the reinforced webbing. A similar design provides connection for a tubular spreader where an engineered plastic receiver includes a protrusion or stud whose diameter matches that of the inside of the tube, and a base forming a flange, which is similarly attached to the webbing. The tube end bears on the plastic flange. Alternately, instead of a stud, the receiver may comprise a circular slot of the same dimensions as the tubing walls, with similar base flange as above.
The patterning scheme for the construction of the sling of the embodiment shown in
The body of the sling, comprised of contoured load supporting surfaces integrated with strategically shaped side panels, is a complex geometry that cannot be formed from a single flat piece of material, so it is assembled from multiple panels as is seen in the Figure. Even so, the three flat pieces in the pattern, when assembled, produce an approximation of the continuously curving shape of the desired body pocket, but the flex in the fabric allows the assembly to conform to the user.
The grain of the fabric must be oriented in alignment with the tension forces for structural integrity of the sling. All three panels are cut with the fabric grain orthogonal to the centerline of the pattern, and when laid flat, will retain a uniformly rectangular grain alignment. However, once assembled into its 3-dimensional form, the grain in the side portions will fold inwards to be oriented similarly to the radial pattern of the forces described above.
The exact shapes required for satisfactory performance of the sling are not intuitively discerned, so dimensions will be specifically derived. Principle dimensions will be aligned with the grain of the fabric and the predominant tension forces in the sling. These may be found by taking cross sections of the sling at intervals along its length, where the planes of the sections are approximately aligned with the radial pattern of the tension forces, which will render them roughly normal to the suspension lines.
Each pattern piece has a unique shape that can be constructed with an array of mosaicked polygons. Dimensions for these polygons are provided by taking the path length of the cross sections of the sling and the spacing between those cross sections at suitable points along their length. The dimensions describe sets of elongated polygons, oriented from side to side across the sling, that are broader in the mid-section and narrower at the edges. In assembling the sling, midfield seams running crosswise in the hip area need to be structurally sound to sustain the diagonal forces of conformation. Also, the lower edge under knees should be durable and robust, as it frequently endures focal strain from the weight of the user's legs.
The length of the suspension lines above the spreader is found using standard trigonometry with the prescribed angles and offset between the apex and the spreader.
The length of the line below the spreader is found as a sum of the distances between data points on the suspension line curve as it was calculated to support the load, or it may simply be produced empirically by stitching the suspension line webbing into the contoured sling edge, then measuring off a suitable length to complete the desired overall size of the device.
Referring now more specifically to
In
These suspension lines span from the upper extent of the hammock device, where they join to form the apex 131, to the lower extent, where they join to form the vertex 132. Upper and lower connection loops, 133 & 134 respectively, are integrated into the terminal ends of the suspension lines, representing the extremities of the device. A rigid spreader 150 is positioned between the suspension lines near the top edge of the seat pocket and is retained at each end by spreader fastening means 155 (not illustrated).
An optional footrest 243 is comprised of a suitably sized panel of fabric having channels formed along the left and right ends, through which the suspension lines pass to support it, thus allowing it to be positioned or moved to a convenient distance from the seat pocket.
Upper and lower anchor lines 111,112 may be utilized to connect the device to upper and lower anchors (not shown), or the connection loops may be attached directly to anchor points without the use of extension lines.
The construction pieces include, centrally, a main seat area 241, a transitional hip area 243 and a seat back area 242, whose lateral boundaries are indicated by dashed lines. In addition, positioned laterally outward from the seating surfaces, they include the lower, middle and upper portions of side panel 201 and lower, middle and upper portions of side panel 202, which are suitably divided between the three construction pieces.
The profile of the lower seat piece is here shown with one straight edge that becomes the lower end of the seat pocket by the user's knees, and symmetrical about the centerline, left and right edges curved to accommodate the suspension lines, and an inward edge curved to accommodate the shaped junction with the tail piece.
The profile of the middle transition piece includes a first edge curved to accommodate the junction with the lower seat panel, and symmetrical about the centerline, shorter left and right edges curved to accommodate the suspension lines, and a fourth edge curved to accommodate the shaped junction with the seat back piece.
The profile of the back piece includes an inward edge curved to accommodate the shaped junction with the tail piece, and symmetrical about the centerline, left and right edges curved to accommodate the suspension lines, and a straight outward edge that becomes the top edge of seat pocket.
The seat panel areas are sized and shaped to accommodate the body profile of a typical male outdoor enthusiast sitting in a reclined posture, such that the lateral dimensions of the flat pattern areas account for the semi-elliptical cross-sections of the seat pocket approximating the shape of the user's back surfaces.
The side panel areas are sized and shaped to accommodate the span in three-dimensional space between the boundaries of the seating surfaces and the compound curve and slope of the suspension lines. Although the lateral curve is segmented between the three pattern pieces, when assembled, this will conform to the crucial shape of the suspension lines as they support the distributed load and maintain conformational forces in the chair.
In practice, the pattern will have suitable margins added to accommodate seams—along the left and right lateral profiles to where the fabric may be wrapped around and stitched to the suspension line webbing, at each inward profile to provide for panel junctions, and at outer edges, to provide for finishing hems, or as provision for additional features not shown.
The pattern shown is an approximate representation, rather than an exact scaled profile, and serves the particular example shown in
With the implication that the devices have near and far sides that are symmetrical about a centerline, each example is comprised of suspension lines 120 under tension between high and low anchors (not shown), suspending a fabric body pocket 200 comprised of side panels 201, whose upper edges are attached along their length to the suspension lines, and lower boundaries are attach to a bottom panel 213, which joins the two, to support a user 300.
A user 300 is seated in a lightweight hammock chair 710 having a chair seat portion 241 and a chair back portion 242 suspended between left and right suspension lines 121 & 122. High tension forces T, indicated by bold arrows overlaid on the suspension lines, are carried from an upper anchor (not shown), through the left and right suspension lines to a lower anchor (not shown).
A soft spreader and air cushion flattening device 770 is positioned between the user and the chair back panel. Air pressure forces P within the soft spreader are indicated by arrows pointing outwards, normal to the surfaces of the device. Dashed lines represent internal ribs, baffles or some mechanism within the device to help retain its shape.
The figure elucidates that air pressure will be equal throughout the soft spreader, and therefor pressure forces on the outer walls will be uniformly distributed—forward against the user, and laterally and rearwards against the hammock fabric. We see that the shape of the device provides a generally flat forward surface to support the user's body, and the convex rearward surface of the device accommodates the curvature of the hammock sling and the deflected tension required to provide forward support of the user. We also see that pressure within the device pushes out laterally, acting to spread the suspension lines, and thus maintain a wider seat back supporting area. Recognizing that the high-tension forces within the suspension lines render them hard and uncomfortable to lean against, we see that the soft spreader and air cushion flattening device acts as spacer, transmitting force between the fabric chair back and user's body, setting the seating surface forward to support the user's back away from the high tension of the suspension lines. Further, we can easily visualize how adaptations to the forward surface of device and the use of varying air pressure could be used to provide varying degrees of lumbar support to the user.
A hammock chair is constructed with suspension lines 120 to span between high and low anchor points (not shown), being held apart at the head end by spreader 150, to suspend a seating surface comprised of a chair seat portion 241 and chair back portion 242, via a multiplicity of tension-bearing cords 205 and 206.
In
The example of
This example demonstrates that a device qualifying as a hammock may be comprised of rigid members when the assemblage of those members is pliable in at least one dimension and suggests that the load supporting surface may be an assemblage of parts of any material of suitable shape, including dowels or tubes. It further indicates that elements of the load supporting surface may function as spreaders.
A new type of hammock device is seen in a bridge style hammock having one, common, suspension line and no rigid spreaders. The design is enhanced by a steeply sloping suspension system and the inclusion of a lower soft spreader.
There are occasions where hammock users prefer a light weight, simple device that can be easily stuffed into packs or bags with little regard to how it is done. For this, it is desirable to have a compact device with no hard parts. On other occasions, the greatest need may be for an example that is better resistant to wind and rain, or there may be a need for a device that has a low profile when deployed, for example, on big wall climbs. At the same time, these users may also still want a reliable, flat lay. Many examples of modern Mayan hammocks are light weight, simple and compact, but they give variable, unreliable results for a flat lay, and the diagonal posture needed isn't suitable in some situations. Bridge hammocks are renowned for their ability to provide a flat lay, but they are more complex, both to manufacture and assemble; existing examples include rigid spreaders and attachment parts that must be packed with care to not be lost or damage other pack contents. In addition, when deployed, their overall shape and breadth is significant, with hard corners that can be obtrusive or get damaged.
Objectives of this example are to provide a bridge hammock with a simplified design that eliminates hard components, is of reduced material weight, and is usable in diverse locations and in multiple modes.
This invention is a new type of bridge hammock having a single, central suspension line, and no rigid spreaders, and having a load sling whose side walls join together centrally overhead on that suspension line. The device is suspended between two horizontally spaced anchors. As in other bridge hammocks of this disclosure, the fabric body is comprised of a load supporting surface and shaped side walls that integrate the boundaries of the supporting surface with the curve and slope of the suspension line. Unlike previous bridge hammocks, the sling wraps all the way around the load to fully enclose it above and below. The ends of the body sling may be open or enclosed. However, as elucidated below, the shape of the sling is conducive to a closed foot end, and a closeable head end may be desirable.
The Single Line suspension system of this invention may be sloped to any degree, including level. However, a notable aspect of the design and function of this example is the inclusion of a significant collective slope in the suspension, producing geometry for the device that is complimentary to the single line concept. This slope of the suspension system and the enclosing sling produces an asymmetrical hammock tent that is narrow and short at the foot end and wider and taller at head end.
This distribution of volume accommodates the natural proportions of the body of the occupant as well as the need for space to carry out activities inside the hammock tent. The larger head end also allows end entry and facilitates adaptations for various modes of use.
The basic device is complete with only the suspension line and fabric sling below it. However, forces of lateral squeeze on the user, including shoulder squeeze, may be reduced or eliminated, and the user's comfort enhanced, by the inclusion of a soft spreader or air cushion flattening device, an inflated object which provides lateral spread to the side walls adjacent to the user. Alternatively, the user may opt to position extra gear beneath their body to fill volume in the bottom of the sling and thus provide a degree of leveling and spread.
Additionally, it may be advantageous to provide openings at the top of the sling for increased view, ventilation or access, especially if the head end is enclosed. This can be accomplished by the inclusion of a section of duplexed suspension with funicular, as disclosed in another section of this document. The central suspension line curve is interrupted, and the tension divided between the main upper suspension line, which becomes a funicular section, and two inferior lines which are added, one per side. These inferior lines carry a portion of the tension and adopt the curve needed to support the sling, but with much deeper decent, as allowed by the reduced horizontal tension. The interstice between the upper funicular and lower curved lines allows access.
The benefits of this new configuration are multiple. It provides reliable performance and a flat lay, being constructed as a bridge hammock with a strategically shaped suspension line curve to support the distributed weight of the user. The use of a single suspension line and the absence of any rigid spreaders, along with the structural enforcements and hardware needed for their attachments, yields a product comprised of fewer parts and less material than other bridge hammock designs, The result is simpler to manufacture and lighter in weight. Additionally, since there are no hard parts, the product is more compact and simpler to stow—it may merely be stuffed into a bag without risk of its components causing damage. Once deployed, the simple design and absence of rigid spreaders provides a compact, narrower plan from end to end, with a cornerless shape that may be useful in restrictive environments, such as on the side of a rock face during big wall climbs. This same compact design, with its fully enclosing sling and its asymmetry from end to end, results in a product that is more resistant to wind, rain or other elements of the weather. Its sloping ridge profile and narrow, tapered plan facilitate effective partial protection by a sloping over-set rain fly, or full protection by an enclosing one.
The novel features of this design result in a product that will be useful in more places and in diverse modes. First, it is more likely to be available when needed, as its compact and light weight construction render it more likely to be included in a user's kit. As a sloping hammock of this invention with a suitably proportioned suspension system, it may require only one elevated anchor point, with the second being near or at ground level, a scenario which is much more common than two suitable elevated anchors.
The asymmetry of the design renders the device well suited for use as a bivvy bag or ground pitched ridge tent if needed, with its proportional tallness at one end allowing the user to sit up erect within the protection of the device. If available, a trekking pole or two may be used as riser poles to hold the apex aloft. If a soft spreader is included, this may conveniently serve as an air mattress for protection against the ground. Lastly, the device may be hung high off the ground and successfully entered through the end, a mode that may be useful to rock climbers or adventurers who wish to be out of reach of ground-based hazards, or simply enjoy the novelty and poetry of it.
A single suspension line 120 with a significant collective slope and characteristic curve spans a distance between upper and lower anchors (not shown) to suspend the hammock system.
A user 300 lies supine in a generally flat horizontal posture upon a soft spreader and flattening device 770, which is contained within, and supported by, the fabric body of the device 200.
The fabric body is comprised of left and right-side panels 201 & 202, extending in length from the upper apex 231 of the hammock to the lower vertex 232, and are joined along their top edges to the central suspension line and along their bottom boundaries to a bottom floor panel 213, to form a tubular sling the length of the hammock.
The diagrams elucidate the simplicity of the structure provided by the single suspension line bridge hammock, most notably the absence of any rigid spreaders. We see the virtues of the asymmetric proportions, and that the sling encloses the user above and below and may also be enclosed on either end. It may be noted in its construction, that the upper edges of the side panels become the outer edges of the material pattern of the sling and are cut to accommodate the characteristic curve of the suspension line. In addition, we see one application of a soft spreader and flattening device employed to spread the side walls of the device and recognize that the top surface of the flattening device could be contoured to provide customized support for the user if desired.
A full-length soft spreader 770 provides a bed surface for the user (not shown) inside the open ended fabric body 200 of the device, which extends from apex 231 at the upper end to the vertex 232 at the lower end, to form an enclosure which wraps around, contains and supports the load. The upper edges of the fabric body are attached to, and suspended by, the single overhead suspension line 120, whose extremities extend to upper and lower anchors, and whose characteristic curve defines the upper profile of the device. Optional grab loops 735 and supporting structural webbing facilitate entry and exit through the end of the device.
The diagram illustrates the relative simplicity of the structure and absence of hard components. In addition, we see that the shape provided by the sloping suspension system suggests and accommodates entry and exit through the end of the device.
D. Animal SupportPet owners like to provide comfortable, elevated places for their pets to sleep, but most of the solutions to this need are rigid objects, making them expensive and bulky for retailing, transport and storage when not in use.
The present invention may be embodied as a sloped hammock device serving as a suspended pet bed that is comfortable, light weight, economical and collapsible. The device may be a single level load pocket, or it may be an array of such pockets arranged to form a multi-level pet bunk bed.
The device may be constructed in a wide variety of ways—it may use two, three, or more anchors, such that the suspension lines may be individually affixed to solid surfaces, or alternatively, they may be held apart by spreaders, and then join to common apex and vertex points, which may then be suspended by individual anchors.
The illustration shows that a hammock may have multiple body pockets in one device, and that a sloped suspension system facilitates diagonal tiering of such pockets, and that functional body pockets for separate load portions may overlap. The design provides utility for multiple users, with the tiered structure providing variety and ranking for the animals' social needs.
E. Tiered PlanterMany people enjoy planting vegetables or decorative plants around their house and yard in containers, either just for a season, or indefinitely. One popular variation is to arrange the containers in a stepped or tiered fashion for aesthetic or functional reasons. Containers for this purpose are commonly provided in wood, plastic or metal, but these may be expensive, and are necessarily bulky for retailing, transport and storage when not in use.
The present invention may be embodied as a sloped hammock device serving as a novel planter that is light weight, economical and collapsible. The device may be a single load bearing pouch to contain potting soil and plants, or it may be an array of such pouches variously proportioned to form an aesthetically pleasing tiered planter. The device may be constructed in a wide variety of ways—it may use two, three, or more anchors, such that the suspension lines may be individually affixed to solid surfaces, or alternatively, they may be held apart by spreaders, and then join to common apex and vertex points, which may then be suspended by individual anchors.
The illustration shows that a hammock may have multiple body pockets of varying sizes in one device, and that a sloped suspension system facilitates diagonal tiering of such pockets and may provide an aesthetically pleasing arrangement of the loads. The design provides utility for inanimate loads.
F. Duplex Suspension System and FunicularIn a bridge style hammock, a duplex suspension system includes auxiliary suspension lines added along sections of the device to carry portions of the tension born by the primary lines, such that the load-bearing tension is divided between upper and lower elements of the suspension system, altering the direction and position of that tension and altering the resultant curvature of main suspension lines, and altering the shape of the hammock sling where it interfaces with them.
The curvature of the suspension lines is a product of the distribution of the load and the terminal angles of the suspension system. On the high end of the hammock, the body may be very deep. Also, the curve of the suspension lines required to support the load across the length of the device may not correspond to the shape we desire for the intended use. A hammock design may call for the isolation of sections of the hammock to allow the local function to differ in character than that of the rest of the system, where sections of the suspension lines may need to be at different angles, tension, elevation or shape than overall suspension system. We may wish to alter the shape of the sling or in some examples, provide improved openings for ventilation or ingress and egress, reduce or lower the fabric side walls to improve aesthetics, open the field of view, add features or reduce weight. We may wish to provide structural elements at other locations on the device not in the path of the main suspension lines.
The invention includes the connection of additional suspension lines along portions of the main suspension lines such that the longitudinal tension is split between the two.
The addition of auxiliary tension members allows a section of the suspension curve to have an altered shape, tension or orientation than the overall suspension system. Secondary suspension lines allow us to reshape the side walls of the sling. On the high end of the hammock, the body may be very deep. We can reduce the amount of side wall coverage by providing a second suspension system that is duplexed below the first and nested within it.
The interruption of the main suspension lines allows the cutting away of portions of the hammock body side panels where an opening or secondary feature is desirable. In the “Single Line” bridge hammock, secondary suspension lines above a portion of the sling allows openings for access and view. The duplex load bearing line also allows us to place non-load bearing fabric, like mosquito netting, between the bed portion and the top suspension line. In the chair example, the alteration could be used to adjust low back support without altering entire sling, allowing the redistribution of load forces and versatility in position and shape of support panels.
A secondary suspension line spanning from one end of the hammock to the other is referred to as a ridgeline, which may serve multiple purposes. A ridgeline can be used to create a funicular suspension system that allows a shallower hammock pocket while still maintaining a steep overall slope. A ridgeline provides versatility in direction of anchor line angles. The ends of the suspension line curve must conform the angles of the anchor extension lines to satisfy static equilibrium, and tension is necessarily parallel to those angles. The addition of a secondary line carrying a variable portion of the tension in a different direction across the hammock allows variation in the direction that anchor extension lines may project while still maintaining static equilibrium.
The diagram elucidates that the funicular line will bear some of the longitudinal tension of the suspension system, and that the direction of that tension is different from the tension born by the main lines, and that the curvature of the main suspension lines is altered and lowered as a result of the reduced tension.
A bridge hammock is asymmetrically proportioned such that it is significantly larger and taller at the head end than the foot end, such that a person may sit upright inside, and enabling entry and exit through the end of the hammock body. The device is adapted to allow the repositioning of lateral spreaders to serve as a lofting pole, and includes other features and adaptations rendering it well suited for ground pitching and other alternate uses.
Recreational hammocks, and especially camping hammocks, are expected to perform a variety of roles in considerably varied circumstances. The most basic needs experienced by all users are for comfort and convenience while sleeping or lounging in their hammock. However, one consideration that cannot be overlooked in a commercial sporting goods product is the aesthetic appeal. Many users prefer gear that is attractive, has a certain “cool” factor to it, and reflects positively on their capabilities and style. Unfortunately, many bridge hammocks are bulky, boxy, and unattractively utilitarian looking in shape.
Functionally, the shape and allocation of volume of typical hammocks does not match the actual need. Not only is the size of the torso and arms wider than the seat and legs, but there is a greater need for lateral space to move things around when performing various activities or simply to stow gear within reach. Traditional bridge style hammocks are generally rectangular in plan view, both ends being essentially the same overall size. Similarly, a Mayan style hammock will almost always be uniformly narrow at the ends and wider in the middle. Yet the simplest observation reveals that the human body is more sizable around the torso, arm and shoulder area than the legs. Therefor the most basic design refinement would be to proportion the hammock accordingly.
The next consideration to note is that, although hammocks tents are generally intended to carry the occupant in a recumbent position, users frequently sit up in them. This may be simply to adopt an upright and outward looking position while they rest, enjoy the view or converse with others, or it may be to facilitate certain tasks, like organizing gear or eating. In this case, it is highly desirable to have overhead clearance so that they may sit upright and not be impeded by the bug net or rain fly, if deployed. In addition, we note that the human body seated upright is more top-heavy than when recumbent, creating an unstable condition, placing them at risk of tipping over.
One circumstance in which a hammock must change its nature is where there are no trees or other suitable anchor points from which to suspend it. In this case, called “going to ground,” the hammock system is used as a ridge tent, pitched on the ground surface, where the bug net can still protect the user from pestilence and the rain fly can protect against elements of the weather. One look at a popular style of Mayan hammock deployed in this manner reveals just how unsuitable they are for this purpose, both lacking in vertical clearance or usable volume. A similarly deployed standard bridge hammock suffers in the same manner, but less severely because of the end dimensions of the side walls and its generally flat bottom. In both cases there is a loss of vertical dimension due to the sag of the hammock bed portion being replaced by the flat ground. Also in both cases, each style is typically the same size at both ends—which is too small! Several existing examples have been presented for the purpose of converting between hanging deployment and ground use, but these examples are merely tents stacked on top of either a leisure or trampoline style hammock, adding complexity and weight to the package.
Another alternate use for hammocks requiring novel adaptations is the deployment of the hammock high above the ground or at elevations where it cannot be reached from flat surfaces beneath it. The needs presented are described in another section below.
The present invention may thus be embodied as a camping hammock that is both convenient and comfortable for standard usage, while also being well suited for alternate uses. More specific objectives of this novel configuration are to provide a multi-purpose tent-hammock with a more refined, aesthetically pleasing shape, and a structure that is optimized for use as either a normally suspended hammock with access from the ground, or as a hammock suspended high above the ground, beyond reach, or as a ridge tent pitched on the ground surface.
The above objectives are met by the invention of a hammock having asymmetry with adaptations for alternate uses. The invention is a bridge hammock that is proportioned to provide significantly increased height and internal volume at one end, and includes adaptations for alternate uses, whereby the body of the hammock itself may serve as the body of a tent, and where the structure of the existing hammock suspension system may be utilized to hold the tent erect and maintain its shape, and where one or more lateral spreaders are easily converted into a vertical riser pole for ground pitching.
While the notion of asymmetrical hammocks is not new, nor the idea of hammocks converting for ground use, the combination of both the geometric proportioning and suitable adaptations, rather than structural additions, allowing the fundamental components of the bridge hammock to meet all needs serving in multiple roles, is novel.
The asymmetric design reapportions the volume of the hammock from the foot end, where little is needed, to the head end where the body is largest, allowing the user to sit up and engage in activities, and be unimpeded by a bug net or rain fly overhead. This asymmetry is facilitated by a significantly sloping suspension system, and therefor can be accomplished with minimal increase in material cost or weight.
In addition, the greater height and overall area at the head end of the hammock facilitates entry through the end of the device, below the suspension lines. This allows the suspension system to remain undisturbed and hold the tent erect while the user enters through the end, at the high side of the tent and rain fly, if deployed, which is highly advantageous when ground pitched. This same end entrance is available if the device is deployed high off the ground, allowing access without tipping the device over, as described in another section.
The greater depth at the end of the hammock sling where the greater proportion of the user's weight is positioned, and where activities take place, provides increased stability against tipping and rotating around the axis between anchor points.
The asymmetric design and inclusion of minor fitments provide a hammock tent well suited for ground pitching. The body of the hammock serves as the body of the tent. Unlike those examples that include additional tent structure stacked on top of a hammock, this is a hammock that may be set on the ground, retaining its same general size and shape to serve the role. The height of fabric side panels of the hammock body renders them well suited to serve as side walls of the tent, being tall enough to provide overhead clearance for the user to sit up inside. Likewise, the bug net and rain fly serve without modification, in either type of deployment.
The structure of the hammock suspension system serves as the structure to support the tent on the ground. While in suspended mode, longitudinal tension develops in the suspension lines between elevated anchors, and width is maintained from within by the stiffness of the spreader. In ground pitched mode, longitudinal tension is provided by two guy lines—one at the head end, attached to the suspension line apex, which it held aloft by a riser pole, and one from the vertex at the foot end. The width of the tent is maintained by guy lines pulling laterally outward from small attachment loops near the connection points of the head end spreader.
Hammock spreaders serve as a tent riser pole. One or more spreaders are easily repositioned from their roles within the hammock providing lateral spread to providing vertical loft of the suspension line apex. The greater width of the asymmetric design includes a longer spreader than is found in symmetrical examples, optimally providing greater height when used as riser pole. In addition, a second smaller spreader from the foot end of hammock, if included, may be coupled with the larger spreader to provide increased height of the riser pole.
The asymmetric design provides improved weather resistance. The sloping geometry allows for the rain fly to easily extend to the ground when deployed at that level, and whether on the ground or suspended aloft, if the small end of the device is positioned towards the prevailing winds, the prow-like shape effectively deflects elements of the weather over and around the device. Further, in suspended mode, the rain fly may easily be sized and adapted to fully encompass and enclose the body of the hammock bed for greater protection, while still allowing a useful opening at the head end. Finally, an asymmetric shape is considered more aesthetically pleasing than the boxy, rectangular shape of traditional leisure and bridge hammocks. When deployed as a ground-pitched tent, the utility of its shape suggests that it belongs there.
The bridge hammock structure is comprised of matching far and near suspension lines 120 spanning from an upper connection loop 133, attached at the suspension line apex 131 to the lower connection loop 134, attached at the vertex 132, being held in tension by anchor extension lines 111 & 112, which are remotely attached to suitable anchors. Side tethers 724 extend from attachment points on the suspension lines to suitable ground anchors positioned to the sides of the device, having been attached at or near where the main spreader is typically positioned for suspended use of the device. The upper apex 131 of the suspension system is held aloft by the 3-part collapsible main hammock spreader 151, and optionally extended by a secondary spreader 152 or any suitable rod, with its lower end resting on the ground.
The main fabric body of the hammock 200 is comprised of a near side panel 201, a matching far side panel (not shown), a body bed floor portion 213 and an end panel 215. The upper edges of the side panels are attached along the length of the suspension lines and held aloft by the same. The lower edges of the side panels extend to the ground, and along with the bed floor portion, rest upon it.
The hammock body 200 is enclosed for camping by a bug-proof net 810 attached at the upper edges of the main body and extending from the top of the end panel 215 down to the drawstring sleeve 746 of a stuff sack 740 integrated into the tail end of the hammock and is fitted with a zipping closure means 811. A ridgeline 140 spans from its upper connection point at the apex 131 to its lower connection point at the vertex 132, and may support an optional rain fly, (not shown). The body end panel 215 may be fitted with an opening door panel (not shown) for an optional end entrance.
The figure elucidates that a bridge hammock with a significantly sloped suspension system facilitates an asymmetric design that is well suited for ground pitching, such that its normal proportions as a light-weight portable hammock render it tall enough for a user to sit up inside, in spite of the loss of some vertical height due to the flattening of the floor as it sits on the ground. Further, the inherent height renders it suitable to be adapted for entry through the end, below the normal position of a suspension line spreader.
It is also apparent that the ridgeline shown will both maintain the shape of hammock tent against the tension, at a variety of angles, from the end anchors and support a rain fly in the optimum position. It can also be inferred that, while pitched on the ground, the tension of the side tethers performs the same function as the compression of the rigid spreader performs when the device is suspended, maintaining the distance between suspension lines and breadth of the hammock-tent.
H. End EntryAdaptations to a bridge hammock are made whereby entry may be gained through the end of the hammock body and below the main suspension system, to the benefit of non-standard uses.
Hammocks are occasionally used in circumstances quite different from their traditional mode of deployment. In such cases, the normal method of entrance and exit from the side may be inconvenient or unavailable. The advent of the asymmetrical bridge hammock presents us with opportunity to provide another method. For the sake of comparison, we first consider a hammock in normal usage, and note two behaviors. In a typical scenario, a camping hammock is suspended a short distance above the ground between two trees, and a rain fly is stretched out above it such that the ridge is in-line with the hammock body, and lateral portions are tied out to the sides. Firstly, we note that to enter the hammock, the user can simply duck down or stoop below the side portion of the rain fly to approach the side of the hammock and climb in. Secondly, we note that actually climbing into the hammock requires the coordination of several elements. The fabric of the hammock body is light and may easily fold up or swing out of position if mishandled. Also, the entire structure is typically anchored at only two points, and thus may easily rotate about the axis created between those points, and affectively dump out any contents or make it impossible to enter. Therefore, for best results, the user would establish a stable relationship between their body mass, the ground, and the hammock structure by adopting three points of contact. This is accomplished by standing at a point on the ground near the mid-portion of the hammock and using both hands to grasp both sides of the hammock. They then must simultaneously hold it open while applying equal pressure to both sides as they transfer their body weight from their stance on the ground, over one side of the hammock and into the pocket. This may involve either pulling themselves up a little, or lowering themselves down, depending on the height of the hammock above the ground.
We again consider the occasion where a hammock is pitched on the ground as a ridge tent. In contrast to normal usage, a hammock “pitched” on the ground would also have a rain fly stretched over it and staked out to either side, but in this case the rain fly may extend all the way to the ground. In order to enter the hammock, the user would need to unfasten, or otherwise disturb the side of the rain fly, lift it up, hold it out of the way and climb in, and then reposition the rain fly. Alternately, they could approach from the end and attempt to slide along the side, in between the body of the hammock and the rain fly, which would probably require crawling. In almost all cases, hammocks are entered from the side for reasons of their geometry, being too small and structurally unfit to enter from the end. In most uses, this is completely adequate, but in the event of ground use, it would be advantageous to gain access from the end where the rain fly is higher, and in the case of the asymmetrical bridge hammock, the vertical clearance is greatest.
Another circumstance where a hammock must perform in an atypical manner is when it is suspended high above the ground. This may be done for reasons of poetry, aesthetics, security, or to accommodate the terrain. In this situation the user will most likely be required to climb up a rope ladder or tree, or other support structure, to approach the hammock. There will most likely be no surface on which to stand, so their weight must somehow be suspended while they enter and exit. Since a hammock is typically only anchored at two points, as a whole it behaves like a cable, and can provide no torque or lateral support, so their mass can only hang directly below the suspension axis. As previously pointed out, normal entry requires the transfer of body weight up and over the side of the bed pocket. Grasping the side of the hammock in an attempt to hoist their body weight over the side will cause it to rotate, and probably dump any contents, comparable to attempting to enter a kayak while swimming in deep water next to it. Also, the fabric under tension may be drawn taught into a narrow strand, thus deforming or closing off any pocket the user intended to enter. Beyond that, it may not even be possible to reach the midsection of the hammock without additional lines being set. It is more likely that the user must gain access from the end, and for most traditional tent hammocks, this provides yet other challenges. While the end of the hammock is more likely to have structure that's suitable for supporting a climber's body weight, the shape of the end provides no openings. The climber would need to get around it, to the side, for the same outcome.
Therefore, the present invention may be provided in to create an alternate form of entrance into the hammock to facilitate alternate uses. More specifically, in the case of a tent hammock pitched on the ground, the objectives are to provide a route of entrance near the tallest end with the most overhead clearance, and where a user may enter with minimal disruption of the rain fly, if deployed. Also, in the case of a hammock suspended high above the ground, the objectives are to provide a route of entrance that it is easier to reach from a nearby structure, like a tree, or when free hanging in a span, far from any structure, and provide more suitably placed elements to enable the user to safely and securely enter the hammock, and to accomplish this without causing the sling to fold or flattening as a result of tension, and without disrupting the equilibrium of the hammock or the arrangement of its contents. An additional objective is to facilitate the provision of an openable closure, in the manner of a tent door.
The invention includes a bridge hammock configured with a sling that is large enough on at least one end for a user to easily pass through below the structure of the suspension lines and spreader and includes adaptations to the suspension system structure to suspend and support the weight of user near the opening as they climb up to gain access and as they enter and exit, and optionally is provided with an openable end panel enclosure of the sling.
In implementing the invention, the sloping bridge hammock of this disclosure may be asymmetrically proportioned to have a large head end without undue increase in the overall size and weight of the device. Connection points, such as webbing loops, may be fitted on the suspension lines to receive removable suspending devices, such as a rope ladder or etriers. These connection points may be positioned on or near a spreader, which holds the suspension lines apart, maintaining the width of device and preventing folding or flattening due to tension. Grab loops or other fitments may be provided at the sling opening to support the user as they transition their weight from the external supporting means into the support of the hammock sling. The edge of the sling encompassing the opening may be structurally reinforced to bear temporary point loads introduced by the passage of the user, or to support grab loops or ladder connection points at an elevation below the main suspension system. The end of the sling may be fitted with a fabric panel, removably attached along all or part of its periphery, in the manner of a tent door with a zipper closure.
The benefits seen are that the invention provides utility for ground pitching, where the user may conveniently enter at the high side of the rain fly without disturbing it, and below the suspension lines, when their structure is used to hold the tent erect. In addition, we see that end entrance enables the hammock to be practically deployed in high places, where access is gained by climbing up an adjacent structure or auxiliary device, such as a rope ladder, and that the configuration positions the weight of the user beneath the spreader and suspension lines, and directly below the axis of rotation, precluding accidental rotation or major tipping of the hammock. Additionally, there is no need to disturb any bedding or contents positioned inside the sling in order to enter or exit.
I. Integrated Stuff SackA bridge hammock is provided with a multipurpose enclosure integrated into the fabric body of the hammock, whereby the fabric body is extended to the joining point of the two suspension lines, and a top panel is added to form a utility space for the user when the hammock is deployed, and a stuff sack for packing the hammock when not in use.
Several needs arise at different points of the cycle in the use of a tent-hammock, challenging the simplicity and convenience people enjoy. The most basic need is for some form of containment to stow the device in a tidy, compact form when not in use, so the mass of fabric and lengths of line don't get tangled in the user's rucksack, or spill all over a closet shelf. Following that is the need to manage the lines in preparation for the next setup. Then, at the time of on-site deployment, the need is to withdraw the hammock and attach it to anchor points with minimal sorting, untangling or repositioning, particularly if being done in adverse conditions, such as foul weather, intrusive vegetation, or dirty ground. Once in use, there is need for a place to stow personal items within the hammock, but where they don't interfere with the user's bed space. Also, it is frequently desirable that personal items be shielded from view for reasons of privacy and security. Additionally, there is a need to stow the bug net or rain fly when not in use, such that they are not in the way, but remain within reach and easily available to the user while they're in the hammock, should the need for them arise.
The current technology presents a number of shortcomings. Most commercial hammocks come with some form of fabric stuff sack, but many of them are separate, making them another piece of gear to handle that could get lost when not in use. While some examples are attached so they can't be lost, none of them provide any means of organizing the contents, which lose their orientation and get tangled. Once deployed, most hammocks have very limited space for storing items beyond the body pocket occupied by the user, and these items tend to slide towards the user, infringing on their comfort and space. Lastly, an open hammock provides no privacy for the goods within it, which may be unaesthetic or present a security risk.
The Integrated Stuff Sack utilizes the existing geometry and fabric at the vertex of the hammock to form a single feature that serves as a stuff sack, organizer, extra storage space and a privacy shield. This is accomplished with a minimal addition of material, complexity or construction steps, and gives the hammock-tent a more finished look.
The concept employs the space at the vertex of the hammock to form an enclosable volume that serves multiple purposes. The fabric body sling of the bed trough is extended endwards towards the point where the left and right suspension lines join at the vertex, or foot end of the hammock, thus forming two sides and a bottom. A top panel is added between the suspension lines to define a volume. The volume is enclosed by constricting the waist of hammock body as a whole at a suitable distance from the vertex. This constriction can be accomplished by a drawstring, which can be carried in a sleeve attached around the circumference of the hammock body at the prescribed distance from the vertex.
The Integrated Stuff Sack serves as a package in which the hammock can be compactly stowed for transport or storage. It is light weight, convenient, and can't be misplaced because it is integral with the device. In practice, the user will stuff most of the fabric body of hammock, along with suspension lines and any extension lines, into the tail end of hammock, then tighten the drawstring to constrict hammock body, and thus contain the bulk of its contents.
The device serves to organize the hammock materials and assists with deployment. It is constructed with the lower connection point of the suspension system exposed such that it can never get tangled up with the rest of the material. This maintains the head to foot orientation of the device, especially if the user stuffs the body of the hammock into the sack progressively from tail to foot.
To deploy the hammock in a quick, orderly manner, the user may connect the exposed tail end of device to a lower anchor, then stretch out the remainder of the device under slight tension until they can connect the upper anchor, without letting the device touch the ground.
Once the hammock is deployed, the volume at the tail end of the hammock body provides an ideal space to store personal items, where they are unlikely to slide into the user's space due to the geometry of the bridge hammock. Additionally, the top panel of the stuff sack serves as a privacy shield, blocking the view of the contents stored within. As an added benefit, the space serves as an ideal place to stow a bug net ready for deployment.
The Integrated Stuff Sack can be adapted with many variations, for example, the same feature could be formed at the apex, or head end of the hammock, but the position and geometric proportions of the foot end make it favorable. The stuff sack construction could be supplied with additional divider panels (not pictured), either internally or externally, forming pockets to facilitate organizing any additional materials stowed in the stuff sack, such as the bug net or carabiners and straps. Another variation may include a second drawstring and sleeve positioned farther up the hammock body, which could be used optionally to enclose a larger volume, which may be necessary for added ingredients like bedding or four season rain flies.
The same concept can be used on a rain fly itself, where the rain fly is supplied with a tail section that fully encloses both the vertex of hammock body and also any ridge line present.
As described above, the present invention represents a new class of hammock device, and the foregoing discussion provided a number of examples in various use categories. Objectives of the present invention are to provide hammocks that are easier to set up, usable in more locations, and have more interesting, aesthetically pleasing shapes. Further objectives are to provide camping hammock beds that are both convenient and comfortable for standard usage, while also being well suited for alternate uses, and to provide hammock chairs that offer greater utility, aesthetic appeal and excellent ergonomic support. A final objective is to advance the art of hammockry by the exposition of design methods developed for the invention.
A glossary of these terms can be found in the Terminology section of Exhibit A forming a part of this application. A mathematical framework for developing bridge hammock systems and methods of the present invention is depicted and described in Exhibit B forming a part of this application.
IV. Conceptual Framework for Invention ProcessAlthough the tangible subjects of this disclosure are specific configurations of bridge hammock, it proves expedient to introduce a Conceptual Framework as a platform on which the inventions have been developed. This Framework requires descriptive terminology to convey specific ideas of hammock design, use and classification.
The following Findings will have value to the designer and are suggestive of considerations required for engineering treatment or conceptual mapping. While similar considerations could be applied to any hammock type, the following sections focus on bridge hammocks. And while it is not within the scope or purpose of this document to provide in-depth analysis of each aspect, the slope and curve of the suspension system is given careful exposition for the development of the invention.
Finding 1—Classify by TypeThe field of hammock furniture is growing at an accelerating rate to produce an increasing variety of designs. Hammock systems can be divided into classifications by type. Meaningful exposition of hammock features and function requires that these devices be classified according to some scheme.
As a first step, a classification scheme must determine whether the device qualifies as a hammock, or might instead be a simple sling, a cot, trampoline or other device. For those devices found to be hammocks, probably the most useful scheme will be based on their form or structure.
Other potential axes exist for placement, for example: what is the primary intended use—an active function like climbing, sliding, sorting/diverting, or simple containment like storage, sitting, sleeping or both; for short term in a back yard or overnight in the wilderness? What is the nature of the load—transient or static, inanimate or animate, non-human or human, single or double occupant? What materials are employed—netting, waterproof fabric, lightweight nylon, rigid lumber slats or bamboo rods?
Finding 2—Comprised of these Components
A Hammock system will be comprised of one or more of these physical components, depending on the type: a sling or load carrying pocket, a suspension system supporting a distributed load, terminal attachment points, two or more anchor lines, suspension lines, secondary or duplex suspension lines, spreaders and attachment means, and lacing between the sling and spreaders or terminal attachment points.
A hammock system may also include auxiliary features which aren't technically part of the hammock proper but are integral to the design purpose. For example, it may include attached storage pockets and pouches, integrated stuff sacks, bug nets, rain flies, lofting poles and attachment means for the same.
Finding 3—Perform these Functions
Components of a hammock system will perform one or more of these functions, depending on the type: attach to anchor points, span a distance, suspend load above the ground, support a load from below, conform to the shape of the load or occupant, contain a passive load within the apparatus, orient load or occupant in a certain posture, enclose a volume of space, protect against the environment, swing, be collapsible and be portable.
Finding 4—Functions are SeparableFunctions performed by components of the hammock system are conceptually separable, even when performed by the same feature. Holding this perspective enhances the designer's ability to engineer the performance of each feature and aids with innovative concept development.
Many functions are clearly seen to be carried out by separate features, but the main sling performs roles that largely overlap, especially in a Mayan hammock. In a bridge hammock, however, it is easier to recognize these roles. We note that suspending the load above the ground is a separate function from orienting that load in any particular posture—a concept central to this invention.
Another example is provided by a soft spreader, which may be designed with the three-part purpose of providing spread to the hammock body, uniform support to the occupant, and a contoured surface to shape their posture.
A third example is found in the side panels of the body pocket, which serve to convey vertical strain and may in some cases convey longitudinal strain, serve as side walls to contain contents inside the hammock, while either blocking the view to provide privacy or permitting the view to allow social interaction. Nemo Cloudview Social is based on providing support while allowing a view.
Finding 5—Tension Forces are Central to PerformanceStatic Tension Forces are central to hammock performance. A structured approach to hammock design will map their role within the device, providing a deliberate configuration of their geometry and effect. An effective mapping will first note the shape and general arrangement of physical components of the device, then quantify and plot the path of tension forces through those components. At a fundamental level, the mapping will outline the hammock's structure, indicating to which family it belongs, whether the device be a Mayan, bridge or trampoline type hammock, for example. In the realm of intellectual property, this mapping will serve as a tool for accurately describing features and classifying patented improvements.
As an analytical tool, it is helpful to the competent designer advancing the art, where fluency with forces and geometry are required to create products with engineered performance. The analytical map serves to predict hammock behavior, and the efficacy of many novel designs is laid bare by tracing the expected path of forces. For example, in a chair example, the need for diagonal tension to provide low back support is indicated and can be provided with a suitable design. On the other hand, the notion to combine part Mayan style and part bridge style will be seen to have distinct limitations.
We see the value of tension force mapping in the study of specific examples, such as the Comfort X hammock, which has a unique combination of lengthwise and crosswise tension intended to level the bed support surface. A force map indicates it be a hybrid, with the major effects being those of a leisure spreader and minor effects similar to a bridge hammock. For the Amok Draumr, the force mapping immediately explains their patented improvement as “a more even distribution of the tension that is experienced in the mid-section . . . ”, but also why a certain type of air mattress must be used with it to prevent collapse of the sling under the legs. In some chair designs, knowledge of conformational forces must be incorporated so that the user gets the intended back support and doesn't slide out of the sling.
Finding 6—Suspension has Characteristic Curve and SlopeAs the hammock suspends its distributed load, it takes on a characteristic curve, and that curve has a slope. This curve is most easily observed in a standard bridge hammock, where specialized suspension lines appear above the load and function separately from the load supporting surfaces.
For the hammock designer, a working knowledge of the geometric principles governing the suspension of the load will enable them to intelligently create any preferred embodiment without reliance on experimentation or guesswork for the shape.
Calculus provides tools that enable us to better conceptualize the mechanics at work in the structure of a hammock. The shape of the suspension line can be derived as the second integral of an equation describing the mass distribution of the load being supported. An overview of these geometric principles is presented in the Appendix.
Other geometric or mathematical methods may be used to achieve the desired result. For example, a piecewise summation of the changes in slope suitable to support the distributed mass also works. The principle remains the same, while the method used should be chosen to best suit the particular embodiment being addressed. For example, a sophisticated designer may use Finite Element Analysis software to example the hammock product, calculating resultant angles and forces in each portion of the hammock components, and thus determining the requisite shape to satisfy the static geometry.
Implementation of Invention ConceptsThe invention concept can be incorporated into a wide variety of products in a new class of hammock, therefor the best mode of use is not a singular shape or embodiment, but the outcome of a successful process to obtain the best design for an intended purpose.
This section outlines a process designers may use to evaluate features of their product as they apply the above concepts in the production of a hammock example of their choosing. Because of the breadth of possible uses for the invention, the process described is not exhaustive, but can only be suggestive of the methods needed. It assumes a person skilled in the art, and must leave specific parameters like actual dimensions, material selection and assembly methods to the informed designer.
Although listed sequentially, key considerations will typically be made simultaneously.
1 Product UseConceptual development of a new product encompasses a number of considerations, beginning with defining the intended purpose and use. We first characterize the load—is it human, animate, stationary, divided or segmented, singular or multiple? For example, the load may be a collection of fruit or vegetables, one or more animals, a person climbing, sliding or sitting, soil with plants, or water.
Next we describe the treatment of the load—what functions the hammock device will perform for the load, and how. Examples include: providing the load with storage with air circulation, complete particle containment, but with water drainage, cozy lounging, or efficient conveying or directing of rolling fruit. Examples for humans include providing a body pocket where a user may lie totally flat or with contours lifting knees and head, recline in a lounge posture or sitting upright climb stepwise up or down with side lines to hold on to, or slide down.
Then we may describe the physical setting where the example will be used, such as in the woods, a residential back yard, a living room or the deck of a sailboat. Further, we may describe the context of its use or frequency of set-up and takedown.
Lastly, the designer skilled in the art will consider the target market or product space for which the hammock is intended. For example, will it be for the economy, luxury, utility or industrial markets, and what is the expected production volume? These factors will further influence material selection, complexity of fitments and manufacturing methods.
2 Design ObjectivesNext we must prioritize design objectives. A targeted product will have multiple objects and associated parameters, where optimization in one area may conflict with another. These needs must be balanced, with the exercise following naturally as an extension of defining the use, and the outcome serving to guide design decisions. For example, in a typical product, it is desirable to minimize costs of materials and assembly, while maximizing durability, comfort, convenience, elegance, style and compactness. In a bridge hammock bed, we may wish to minimize shoulder squeeze while maximizing stability and internal space, or we may wish to minimize packed volume and weight while maximizing the ease of set up.
3 Suspension System DesignThe suspension system is the defining feature of the bridge hammock, and the concepts of the invention are embodied in its configuration. Comprised of the anchors, suspension lines, spreaders, and cooperating features, its form can vary considerably depending on the intended use of the device.
Cross ConsiderationsAspects of the suspension system will be designed in light of their interaction with the following:
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- a. The Intended Use—the suspension system may have markedly different structure for different uses, for example—double occupancy, single line bridge, animal support structure, end entry, and adaptations for ground pitching.
- a. The environment—the design may be modified to reflect the needs of the context in which it will be used, for example, the availability, type or position of intended anchors, or the amount of floor space available.
- b. The Load—how the load will be oriented or postured with respect to the axis, and how the load will be supported against gravity and other forces.
- c. The Body Pocket—how the angle of lines, curve and slope will prescribe the general size of envelope, contribute to its shape and provide structure to suspend the sling.
- b. Its own Structure—how all the components will work together as an ensemble, having the desired angles, slope and forces, and including spreaders, funiculars or attachments.
- a. Alternate Uses—how the suspension system may be adapted to translate into structure for a ground-pitched tent or include auxiliary feature for hanging high and end entry.
- b. Production—material selection and type of attachment for transmission of tension from sling membranes to suspension lines, assembly methods, appearance and weight.
The Suspension System design will prescribe parameters for the Anchors, Suspension Lines and Spreaders.
Prescribe the anchoring scheme—the number, horizontal placement or footprint over ground and their vertical elevation. Together, these determine the 3D shape of the suspension envelope. The footprint may be merely the width of the load sling suspended between two horizontally separated anchor points, or it may include three, four or more anchors for a larger, more diverse shape.
The vertical arrangement of the anchors can be considered in terms of its aspect ratio, which is the tallness of hammock system in proportion to its horizontal length. This aspect ratio and the footprint over the ground define an envelope of space required for the device, which will be characteristic of its type and context in which it is used.
The device may utilize a non-standard anchoring configuration where, perhaps, all anchor points for the functional hammock portion could be provided by a host structure, such as the frame of a lawn chair or folding jump seat.
Determine the number and configuration of the suspension lines to span between those anchors, such that they suspend the sling and provide horizontal tension needed to posture the load.
Determine the type and placement of spreading devices to be used in conjunction with the scheme for the anchors and suspension lines, further described below.
Elucidating the above, we note, for example, that a sling may be suspended between two separate suspension lines, with each end having its own anchors, forming a rectangular array of four anchors, or those same suspension lines may instead be held apart by spreaders and then joined together so they may attach to a single anchor at each end, forming a linear array.
This is the configuration of a typical bridge hammock bed. Other examples for comparison are the Single Line Bridge Hammock, which has only one line hung between two anchors, and the Animal support structure, which may have two lines hung between four anchors (as first described), or certain hammock beds which have two or three structural lines hung between three anchors.
In the cases of the Animal support structure or the Tiered Planter, it may be advantageous for user convenience to provide top and bottom spreaders which then mount directly to an anchor surface or wall, and thus overshadow a smaller footprint. And while cats might not care for tippy hammocks, and thus require more than two anchor points, a wilderness camper will value needing the least amount of anchors for deployment.
Consider the probable need for anchor extension lines and the impact that will have on the anchoring scheme. While not considered part of the hammock proper, they enable the use of anchors that are not immediately adjacent to the hammock and may be well beyond its immediate location. They are frequently essential for certain examples, extending the range of settings where the hammock can be used. An animal support structure would not use any, but for a wilderness hammock tent, they are very helpful.
Angles & SlopePrescribe the terminal angles of the suspension lines. The starting and ending angles with respect to horizontal, or slopes, for each line establish the general vertical profile of the suspension. Include a suitable change in slope in each line to provide the deflection needed to support the load as described in Finding 6.
While it is typical for hammocks to be symmetrical from side to side, and it is traditional for them to be symmetrical from end to end, in fact each end of each line may have a unique angle with respect to the vertical or horizontal.
Suspension lines of bridge hammock devices may leave the device in two, three, four or more directions, with each line having its own slope. The Collective Slope is defined as the average of the slopes of each line. As is disclosed in this Invention, the device may have a collective slope that best serves its intended purpose, where conceptually, this may be any value, being limited in practice only by the application and materials.
Accommodate the shape of the load sling. The angles chosen impact the depth of the curve of the suspension lines where they form the top edge of the sling, forming its shape and providing for its functionality. As with the anchoring scheme, this shape will have an aspect ratio characteristic of its use. For example, products like the Tiered Planter or Animal support structure would typically have a tall aspect ratio to provide elevated separation between load pockets while requiring a smaller footprint over the ground. This is provided by steep angles at the top and bottom. A hammock bed will have a shallow aspect ratio to match the shape of the load and facilitate anchoring. One end may angle up modestly and the other be closer to horizontal, affording the user a view and facilitating anchoring requirements. A hammock chair may have a somewhat square aspect ratio and diagonally oriented suspension angles to coincide with the reclining posture of the user; with the angles being chosen to accommodate the shape and posture of a particular example.
The shape of the load sling must accommodate the unique curve in the suspension lines required to support the load, but this curve can be adapted to integrate with the angles chosen. Also note that the center of mass will fall in alignment with the intersection of the angles projected by the ends of the curve, which can be thought of as analogous to the asymptotes of a hyperbolic curve.
Account for the effect that suspension line angles will have on anchor positions, the use of extension lines and horizontal tension in the system. The steepness of the upper angle determines the potential height of the required anchor, and in a sloped system will have the greatest impact on horizontal tension, which may in turn require a stronger structure or make it harder to reach.
The lower angle chosen may have a variety of effects, including ease of set-up and types of locations the device may be used. An extension line with a shallow angle up or down can be extended farther in deployment, allowing some variance while still providing adequate service. A flat horizontal line can be extended indefinitely with little impact, and a negative angle can be taken to a ground based anchor. It is understood that ground based or low elevation anchors will be more readily available and need not be as unique or structurally robust as higher anchors.
The horizontal tension component in the suspension lines is directly proportional to the weight of suspended load and inversely proportional to change in slope as measured from one end of the system to the other. Suspension lines extending away from the device at two shallow angles will generate greater horizontal tension for a more stressed, “hard” system than two deeper angles, which produce a softer, more relaxed system. Similarly, two positive angles share the load while a negative lower angle adds to both the vertical and horizontal components of the upper line and anchor. The degree of tension or “stiffness” in the system can affect the manner in which the hammock body flexes or deforms as loads shift, which may affect performance in products like the Animal support structure or Step Ladder.
Anchor extension lines extend the tension of the suspension system. Unless a structural ridgeline is used that bridges the suspension curve, they must be deployed with the same angles as the ends of that curve. Then their use will amplify the effects that the angles chosen have on anchor placement. Unless that slope is horizontal, the height of the respective anchor must be altered to accommodate the additional range of that slope, potentially making it more difficult to reach.
Shape of CurveDerive the shape of the suspension line curve. The curve will have a beginning and an ending slope, in accordance with the angles prescribed above. Transitioning between the ends, the slope will increase at a rate proportional to the tension force required to support the load in the hammock sling, this aspect can be important to the function of the bridge hammock, giving rise to the shape of the suspension line curve characteristic of each example.
There are multiple methods by which the curve may be derived.
Closed Form Solutions—If the horizontal distribution of the mass of the load can be exampled by an integrable equation in two variables, where all forces on the suspension line are vertical, then a closed form solution for the curve may be obtained by taking the second integral of that equation. The solution will describe the vertical component of the shape of the curve, as taught in Finding 6. The first constant of integration serves as a coefficient of slope in the final equation, which is the collective slope of the curve and of the hammock system. This may be scaled for accuracy by the inclusion of the horizontal tension component of the suspension system as a reciprocal factor for a math example where the load is normalized.
This solution is sufficient for examples such as the Single Line bridge hammock where there is no lateral component in the shape of the suspension line curve, or for examples where approximations of the lateral component are adequate. For examples with two or more suspension lines, the lateral component may be approximated if the angles of the side walls of the sling are fairly consistent and don't deviate grossly from vertical. An approximation may be constructed using the same second integral of the mass distribution but applying different terminal angles to produce a suitable curve. This generates a pseudo tension coefficient T to scale the solution. The curve is visually fitted to the plan view of the hammock by adjusting the terminal angles and applying a suitable offset, matching the curve ends to the width of the spreader and length of the vertex.
Piecewise FEM—The curve may be derived using a Finite Element Method, FEM, which develops a piecewise sum of the forces acting on the suspension lines. This method may be used in cases where a closed form solution is either unavailable, such as when the mass distribution can't be exampled with an integrable equation, or impractical. Where load forces are not normal to the length of the hammock, but have diagonal or longitudinal components in them, as is found in chair configurations, closed form solutions require differential equations, which may be very challenging or impossible to solve.
The FEM method utilizes standard engineering practice found in the analysis of free body diagrams, where an account is made of all static forces acting on the system in 3D, and a sum of directional vectors is made to solve for static equilibrium.
The geometry of the suspension line may be derived by performing a sequence of calculations at discreet points separated by short intervals along its length. At each point, a sum is taken of the tension of the incoming suspension line and all forces acting on it, including the proportion of the mass of the load acting at that point. Solving for static equilibrium, the resultant provides the strength and direction vector for the outgoing side of the suspension line, which can be projected a distance to the next position. This becomes the next point of calculation. This direction, which embodies the slope for that segment, will trend upwards and outwards as it balances hammock sling tension pulling downwards and inwards. The first calculation uses values for initial conditions at the first end of the suspension line—its position, starting angle, and tension from the anchor, or some other starting point.
The method may be used for just the portion of suspension lines adjacent to the sling, or a complete solution may include the entire length of the suspension lines, factoring in forces from any self-junctions, spreaders or funicular lines acting on them.
Empirical Methods—Another method for deriving a suitable shape of the curve is merely through trial and error. This is more challenging for hammocks with steep slopes or complex configurations, or where not all forces are vertical or parallel. For these and other complex examples, the curve of the suspension lines and associated panel shapes required to yield the desired performance are not intuitive or common geometric shapes that can be easily re-dimensioned.
There are a variety of forces acting in all dimensions to shape the suspension lines. The weight of the load, distributed over a horizontal span, is pulled vertically downward by gravity. In simple lay-down hammock beds, this may be the only significant contributor. More complex devices may have horizontal or longitudinal components from conformation of the load or maintenance of posture. In chair examples, for example, the suspension lines experience significant diagonal strain due to the lean angles of the seat. Lateral forces develop due to differences between the width of the suspension system and that of the load. Also, spreaders press outwards while sling tension typically pulls inwards towards the load, or it may not contribute where the side panels are vertical.
Therefore, while the shape of the curve is most significant in its vertical profile, it is necessarily a compound shape in three-dimensional space due to these forces interacting in all directions. Also, the smooth curves that support distributed loadings may be interrupted by hard corners where rigid spreaders or funicular suspension lines intersect them. In some examples, tension may be shared between the suspension lines and the load sling itself, such that accurately mapping the tension forces presents a notable challenge.
Special consideration must be given to examples that provide complex functionality, such as the Animal support structure, Step Ladder or Shaped Cute, where the load may randomly occupy different positions or move through the device. In such cases, the geometry of the static forces may be complex or modular, and the design would include accommodations for different configurations, noting, for example, that while one portion of the sling bears a load, empty portions will lose shape and be drawn straight under the tension.
SpreadPrescribe how the hammock will be spread. In many examples, spreaders are a key element of the structural frame formed by the suspension system to support the load sling, impacting the number and placement of anchors, the breadth, shape and volume of the device, and ultimately, the user experience.
Bridge Hammocks of the Invention may be designed to utilize a variety of mechanisms to spread the device, producing a range of effects on the suspension lines and, subsequently, the performance of the sling. The means chosen may include one, two or more independent rigid rods, an array of slats operating collectively, one or more soft cushions, a combination of these, or nothing at all, where only the load itself spreads the sling.
Considerable variation is also afforded for the positioning of the spreaders, so the load sling may be produced with a variety of shapes in plan view, including diamond, where a single rod is positioned centrally over the sling in a two line system with joined ends, or triangular, where a single rod is positioned at one end of the sling in a similar system, or rectangular, where two rods of equal length are positioned at opposite ends of the sling, or a tapered quadrilateral, where two rods of unequal length are positioned at the ends of the sling. Alternatively, a soft spreader may be positioned in the lower portion of the load sling and be whatever shape is suitable for the purpose. An array of rigid slats may be arranged to a similar effect.
Rigid spreaders act directly on the suspension lines, generating points of high stress that typically require some means of connection. These junctions produce corners in their shape, representing the extremity of the lateral component of the suspension line curve in 3D space, and producing corners in the sling geometry, if it extends there.
The spreaders shape the load sling, holding material away from the user or load and counteracting side squeeze. Along with the depth of sling, width of load or lower soft spreader, their dimensions determine the angles that the side panels will make. Their position along length of the suspension system may affect the usefulness of internal space. For example, in a lounge chair, an overhead spreader might be positioned beyond where it interferes with the head of the user, but its placement and length will impact the degree to which the suspension lines interfere with the user's elbows.
Soft spreaders may act directly on the suspension lines or be positioned separately to act only on the sling. They may be multifunctional, acting to spread the device while also lifting the load, flattening or contouring the support surface, or providing insulation, for example.
Soft spreaders may be used in place of hard spreaders to shape the suspension with distributed forces, rather than point loads, inducing gentle curves rather than hard corners. They may be employed to simultaneously offset the load from the hardness of high tension in the suspension line or provide padding against it. Soft spreaders may work in conjunction with hard spreaders for a duplex spread of the load pocket, widening the bottom of the load sling while rigid spreaders hold out the suspension lines on the upper portions of the sling. They may simultaneously serve to fill volume in the medial part of the sling to provide a flat support surface to reduce pooling, to provide for double occupancy or other purposes. Lastly, they may act solely on the sling in a system with no hard features.
The use of soft spreaders generally consumes more volume in the sling than hard spreaders, affecting the overall size of the device, which may impact the height of anchors needed or locations the device may be used. The forces provided by soft spreaders rely on the pressure of air or other moldable internal fill material, giving them a lower strength-to-size ratio than hard spreaders, so the effect they have on the tension within the suspension system will be more modest, distributed.
Prescribe the use of any funicular suspension lines. Funicular lines may be included as secondary sections of a suspension line, spanning a part or full length of the curved portion of the main line, and being duplexed vertically with it.
A funicular line carries some of the tension from one point in the suspension system to another, inserting this tension at a different angle from, and reducing the tension in, the main line. This interrupts the smooth curve of the primary suspension line, typically allowing the duplexed section to have a deeper, lower curve without altering the ending angles, collective slope or tension of the device as a whole.
These features may be added for a variety of reasons. For example, they can be used to reposition the strain within the system or customize support for the load. They may be used to partition the suspension line curve and the attached sling into sections, modifying its shape, perhaps to lower the side of the sling for increased visibility. A pair of funiculars may be included in a single-line hammock to create openings for access or ventilation. The secondary lines allow the top edges of the sling to drop below the main line in a secondary curve for a section.
A funicular may serve as a structural ridgeline, spanning the full length of the device to effectively set the shape of the curve of the primary lines against variations in the angles of anchor extension lines. This line is also useful for supporting a rainfly or bug net.
In the structural design of the suspension system, point loads introduced by tension forces carried in funicular lines must be included in calculations for the shape of the curve, and the corners they produce integrated into the shape of the device.
Provide for the inclusion of any auxiliary features that interact with the suspension system. For example, load-bearing grab loops, which would be highly useful for hammocks hung high off the ground, would be attached to structural elements of the suspension system. For those examples designed to enjoy dual use as a hanging bed or a ground pitched tent, features may be included to facilitate the conversion, such as tie-out points for external tethers and attachment points for spreaders repurposed as lofting poles.
4 Body Pocket DesignDesign the load sling. The sling is seen to perform two main roles—serving the load, or providing the user experience for sentient loads, and conveying tension from the load to the suspension system.
The invention is implemented through the principle that the geometry of the load sling cooperates with the suspension system to enable a hammock with any slope. The actual shape of the load sling is incidental to the particular use. The structure of a bridge hammock allows us to separate the posture of the load from the general shape of the suspension system, with this insight and concepts of the invention, we have a great deal of freedom to design a hammock sling that is optimum for the intended purpose.
Design of the hammock sling begins with accounting for the characteristics of the load. First note the nature of the load. It may be animate or inanimate—for example: a person, a small animal, dirt or pool of water. It may be static or active and transient—rolling, climbing or sliding—and it may be rigid or pliable or flowing or shifting. Note the geometry—the size, shape, center of mass and desired orientation or posture of the load. For example, a human may be lying totally flat, lying with raised knees and head, reclining in a lounge posture or sitting upright, standing on one foot climbing up, seated with legs outstretched while sliding down. A basin of planting soil may be shallow and wide or narrow and deep.
Sling GeometryEstablish the overall geometry of the sling. Determine the desired position of the load relative to the suspension system. This will determine not only the shape, but the placement of the forces being transferred from the sling to the suspension, and how the load may interact with features of the suspension.
The vertical offset is the elevation of the load relative to that of the suspension lines and their respective anchors. There is no limit to how deep a sling may be; the shallowness is limited only by the ability of the sling to contain the load.
The horizontal position orients the load end-to-end with respect to rigid spreaders, junctions in the suspension lines, and the lines themselves in examples with significant slope. The center of mass of the load will normally fall directly below the point where the angles taken by each end of the suspension lines intersect. The intended geometry may require adjustment to accommodate this relationship.
Lateral spacing is a product of the width of the load relative to the width of the suspension system, described earlier, and is impacted by the vertical and horizontal positioning just mentioned. Therefore, adjustments to the spacing to accommodate the load begin with changes to the design of the suspension system.
For most examples of bridge hammock, the load hangs between a set of suspension lines, and equilibrium forces naturally cause its center of mass to shift to the center of the sling.
The hammock bed serves as the most straight-forward example because its load is generally elongated and straight, and load forces are generally only vertical. The vertical offset determines the depth of the sling, which in turn determines the size and angle of the side panels. The depth may also affect the ease with which the user climbs in or out and their view from within the device.
In the hammock chair, all three parameters—depth of seat, forward position with respect to the suspension line curve, and width—are critical for performance. For example, all have varying effects on side squeeze and clearance for thighs, shoulders and elbows. A user sitting in the seat generates downward gravitational forces and angled conformation forces as they lean into the seat back. The shape of the seat and relative position of load sets the geometry, determining how and where forces fall on the suspension lines, and where they potentially intersect within the sling side walls.
In the Step Ladder, the depth of the sling affects the pendulum arm from the anchor axis to the user's center of mass and the ergonomics of grasping the suspension lines with their hands while they climb—both factors for stability.
Design the Load Pocket, the lower portion of the sling whose shape and surfaces act directly on the load to support, posture and contain it. Establish a shape that best serves the intended purpose.
Account for the behavior of the selected materials, like stiffness or stretch. For example, in some examples it is desirable that a soft, pliable fabric with some four-way stretch wrap closely around the body of a user, but it may deform easily and not transmit tension in a predictable way. Hard slats of a wooden chair will be uncomfortable pressed against a user's tailbone, requiring relief of the contour at that area, but their dimensional stability will reliably maintain the width of the seat pocket.
Outline the profile of the supporting surface. For a sleeping cat, the profile may merely be a circle. For a human example, the length will be prescribed for their probable height, and the width greatest at shoulders and hips, while narrowing towards knees and feet. For a soft sling looping under the load and transitioning into vertical side walls, the dimensions must match the width of the load. Any excess will fold upwards to become part of the side wall, thus altering the depth of the sling and elevation contour of the load support surface. This will not apply in examples with stiff support surfaces like chairs with rigid slats, where the profile may be shaped more for aesthetic design than body shape.
Design the elevation contour, which is the end-to-end path of the supporting surface through space. This will generally match the posture of the user or load determined above,
Factor in the desired ergonomics to create the intended “user experience” or treatment of the load. For example, in a chair, this includes the lean angle and degree of low back support; in a bed, the variation between a totally flat lay verses a certain amount of mid-body sag for comfort. For a step ladder, this will present the step surfaces incrementing in elevation.
Factor in the requisite structural performance, taking into account the distribution of pressure forces and ability of surfaces to maintain shape and contain the load. For example, in chair examples angled forces on the seat back must be opposed by oppositely angled forces on the seat bottom, and side panels must be able to convey diagonal tension without undue deformation.
Factor in the depth contour of the support surface, which is the degree to which the sling wraps around the load from side to side. For pliable membranes, the surface deforms to accommodate the shape of the load it supports, thus making a three-dimensional contour.
The margins of this contour will depend on the angle of the side walls of the sling and the nature of the supporting surface or the load, which may be flat and stiff for wooden slats, or flowing and moldable for nylon taffeta.
If soft spreader or air cushion flattening devices are included, the design of the load pocket will be customized to accommodate their shape rather than the actual load, to the extent that they are positioned between the two.
Special consideration will be given to loads that are flowable, transitory, modular, or have some other unusual characteristics. For flowable loads like water or soil, load pocket shape will be engineered primarily to contain and support of the contents. Modular and transitory loads will require special consideration to provide the intended support as the load shifts position.
SpreadAccount for how any spreading mechanisms will affect the shape of the sling or interact with the load. Spreaders establish the width of the device and configuration of the suspension lines.
Rigid spreaders operating on the suspension lines alter the path of those lines, which carry out the edges of the sling, producing laterally prominent corners in them that must be accommodated by the profile of the sling side wall. The focal point of tension may alter how the sling flexes and conveys the tension distributed along it. The width of the spreader, in conjunction with the width and depth of the pocket, will establish the angle of the sling side walls in their vicinity.
Soft spreaders and air cushion flattening devices will have a direct effect on sling geometry. Their force will typically act on the fabric side walls of the sling, providing spread that is distributed over an area and along a length, rather than as a point load. Their use will require greater volume within the sling, including depth of the pocket, which may require an increase in the overall height of the hammock system.
Naturally, the soft spreader may increase the width of the load pocket to where it is more prominent than the load.
The shape of sling will conform to the contour of soft spreader, rather than the load, Therefore, the design must be fashioned for the size, shape and relative position of the soft spreader with respect to the suspension system.
These devices may be any size within the parameters of the device, and present partial or complete coverage of load pocket, impacting the shape of load pocket to the same proportion.
A soft spreader or air cushion flattening device is typically positioned between the load and sling material and may include features of ergonomics or function, therefore altering the surface, shape or character of the load pocket experienced by the load. Both the shape and position of the device with respect to the suspension system will impact the distribution of forces from load.
Shaped Side PanelsDesign the side panels of the sling to support the load pocket and integrate with the suspension system. The shape of the side panels enables the invention by providing that the load pocket may take whatever form is desirable, and by accommodating the shape of the suspension line curve and slope as prescribed for the configuration of the device, while conveying tension forces from the load pocket to the suspension system.
Side panels perform multiple roles. In addition to connecting the load pocket to the suspension, they may provide containment of the load, privacy for the load, or protection from the weather. They are engineered to convey forces of gravity, and in some examples, conformation forces maintaining load posture.
The bottom boundary will be designed to cooperate with load supporting surfaces of the load pocket. In construction, the side panels may be a singular piece of material contiguous with the bottom panel, or cut separately, and then joined. In an alternate configuration, the side panels could be attached to lateral edges of a soft spreader device of a different material—the soft spreader serving as the supporting surface.
The top edge and upper profile of the side panels is shaped to accommodate the load bearing curve of the suspension lines to which it will be attached, that curve having whatever slope the designer chooses.
In addition to the lateral deflections produced by rigid spreaders, junctions between funicular suspension lines and main lines will produce abrupt changes in the top edge profile that may require reinforcement or other special treatment.
Auxiliary FeaturesIntegrate any auxiliary features or adjustments to the fabric sling shape in adaptation for its intended purpose. For example, the example may include an integrated stuff sack, end panels on a bed trough, doors for end entry, holes for drainage, internal sleeves or double bottoms for containment of liners, insulation or soft spreaders.
5 Structural Performance Integration of Shape and StructureIntegrate the structural performance of the design. The successful design will account for the configuration of the forces within the hammock system and the behavior of material components employed to ensure their load-bearing capability.
Although tension forces are not seen, they are central to performance, and the design process will verify that the configuration of the device will respond favorably when under load.
The visible shape of the sling may initially be developed to serve aspects of the intended use, including general shape, containment and posture of the load, and at times privacy, protection from the elements and aesthetics. But the configuration must also have the structural integrity to successfully convey the invisible tension forces from the load to the suspension system.
Shape and performance can be adversely affected if the geometry and material properties satisfying the first aspect do not coincide with those needed for the second. In this case, tension may be carried where it is not intended, or shift to a new position, resulting in deformation or other unexpected behavior, such as the occupant of a poorly designed hammock chair sliding out of the seat pocket.
Sequence of DependenciesWhile aspects of the example may be planned concurrently, certain facets of the design relate to each other in a logical sequence of dependencies, so that parameters from one aspect precipitate parameters for the next, governing how each component contributes to the function of the assembly as a whole, a principle true of all bridge hammocks, but of greater consequence for the more complex examples of this invention.
The designer may note the inherent relationship between elements in the following sequence:
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- i. Designation of Use
- ii. 3D distribution of load forces
- iii. overall suspension system design, including slope
- iv. specific suspension line curve
- v. position, width and elevation contours of load support surfaces,
- vi. shaped side panel regions bounded by suspension lines and load support surfaces
- vii. direction of tension forces within the side panel regions
- viii. required performance of material construction chosen for side panels
- ix. pattern “paneling” scheme,
- x. explicit pattern shapes and dimensions,
- xi. cutting and assembly
When the intended use 0 of a new hammock example is described, the load will be defined, with its position and posture presenting a characteristic distribution of load forces 1. Together these dictate the overall design of the suspension system 2 and the specific curve of the suspension lines 3, which may have any slope, according to this invention.
The sling will include a load pocket with load-supporting surfaces 4 defined by a width profile and elevation contour, according to the intended use. The lateral margins of these load-supporting surfaces present a profile shape that serves as a lower boundary to a region of the sling designated as the shaped side panel 5. With the shape of the suspension line curve serving as the upper boundary of this region, the dimensions of the shaped side panel are the difference between these two boundaries, according to the practice of this invention.
The load resting on the support surfaces within the sling generates tension forces 6 that must be conveyed by the shaped side panels of the sling to the suspension lines. The specific materials chosen and their arrangement in the side panels determines how these tension forces are conveyed and the resulting performance 7 of the sling. The scheme 8 for how pieces of material are arranged and joined together to form the geometry of the sling prescribes the exact shapes and dimensions of the pattern 9 needed so that parts can be cut and assembled 10 into a finished product.
Tension Force MappingA successful design process will evaluate static forces in the hammock system. In complex examples, the configuration of forces is not intuitive or self-evident, and reliance on assumptions yields poor results. In order to create hammocks with reliable performance, an engineering method is needed to recognize, visualize and quantify the position, strength and effect of forces within the hammock system.
A Mapping of hammock structure is an engineering tool that will indicate the shape and general arrangement of the physical components of the hammock, and the path of tension through features of the device as they serve to support, contain and shape the load in three-dimensional space. This Map allows the designer to graph the mass distribution, construct free body diagrams and perform statics analysis.
Tension in the hammock system originates with gravity acting on the load as it is pulled vertically downwards. Conformational forces arise in some designs when tension is needed to maintain the shape or posture of the load. These may include longitudinal or horizontal components generated by the lean angle in the seat of a chair or circumferential tension in a load pocket containing dirt or water, for example. Lateral forces are generated as spreaders press outwards against suspension lines, which pull inwards towards the center, and where there are differences between the width of the suspension system and that of the load in the sling.
Tension forces in the hammock system can be characterized by their orientation, order and role. Forces will be oriented with respect to the position of the anchors and the overall shape of the device. A line between anchors serves as a reference for most hammock examples, as well as an axis of rotation in a two anchor system. For most examples, features and forces in alignment with this reference will be longitudinal, while those perpendicular to it will be considered lateral, crosswise or transverse. In chair examples, forward and rearwards or aft relate to the posture of the user, and diagonal forces will typically have a vertical component and be found in the side walls in a forward or rearward direction.
Primary tension is that which is established directly between anchors and will be oriented longitudinally in most hammocks and crosswise in 90 degree hammocks. Secondary tension develops between elements of the hammock carrying primary tension and is typically crosswise or transverse in orientation. Tertiary tension may refer to any other force that isn't involved in suspending the load, and therefor doesn't intersect the suspension system or extend to the anchors. Their roles can be distinguished between directly supporting the load, supporting other hammock elements that support the load, or maintaining the functional shape of the device.
In a Mayan style hammock, primary tension directly supports the load, having a longitudinal orientation, and being conveyed below the load along the bottom surface of a simple sling. Naturally, in smaller bunched end hammocks there is some portion of total tension deviating from this path to uphold the side walls of the sling and contain the occupant, with some tension becoming secondary in nature.
In a simple, classic bridge hammock bed, primary tension is carried by the suspension lines above the load and secondary tension is developed crosswise in the sling between the suspension lines to pass below the load.
The bridge hammock lounge chair includes longitudinal primary and crosswise secondary forces as just described, with the addition of forward and aft diagonal forces generated by the lean of the back support. The back support cooperates with the seat support to generate tertiary conformation forces in the side walls, some of which are captured by the suspension lines, but much of which remains entirely within the side walls of the seat pocket.
In a planter hammock with generally round soil pockets, simple circumferential forces serve to retain the shape of load in the region containing the soil but affect little else.
The hammock force map begins by indicating the posture, shape, mass distribution and center of gravity of the load.
A mapping of the sling will show how tension forces follow a path from the load to the suspension system, and then to the anchors. As indicated above, tension within the sling can potentially be oriented in any direction. It is noteworthy that in many examples, this orientation is not evident from its appearance, but directly impacts its shape under load.
The map will indicate the distribution of tension as it is directed longitudinally, laterally, diagonally, and radially within the sling.
In the bridge hammock lounge chair, the seat pocket spans from side to side between suspension lines, and the back panel of the seat is inclined at an angle. Depending on the cut of the seat pocket, tension will be conveyed laterally between those lines, but may also pull from the bottom panel diagonally upwards to the suspension lines or longitudinally up the middle, causing the top edge of the back panel to droop if not constrained.
While the physical shape of the hammock body shows the presence of material panels or components, the force map will indicate which portions are involved in carrying the strain and which are not. For example, in a hammock bed, the side panels directly adjacent to the suspension lines usually carry significant strain, whereas end panels may not. In a chair, the back panel will carry significant strain, which must be well managed for good performance. These insights allow a more deliberate selection of material types and orientation to best perform the function of each part. Some panels may need to be of a stronger material, while others may allow use of a lighter material to save weight or may need the weave oriented a certain way.
Performing a static force analysis may be straight forward for simple examples, but impractical for complex designs. The flexible nature of hammocks, along with the variability of load shape or position may limit developing an accurate mathematical example. In these cases, it may suffice to recognize the principles inherent in this process, make a working approximation, then gather empirical results, allowing experimentation to guide the analysis.
Some products require more complex analysis than a single static example. A force map might be compound or modular if the load acts in different positions, like walking up the Step Ladder or sliding down the Chute. The sling's shape must account for an instantaneous load profile, but also accommodate alternate shapes as the load moves through the device. The entire weight of the load may rest on one small portion at a time while the rest of the sling is drawn straight under tension.
A Map of the Suspension System will indicate how it receives tension forces from the sling and conveys them to the anchors, thereby suspending the load. The map displays lateral geometries produced by the width of the load and spreaders counteracting longitudinal tension between anchors. The map will indicate the variety, placement and character of any spreading means, including external tension from laterally disposed anchors supporting the device, point load forces from rigid spreaders within the device, above or below the load, or distributed pressure from soft spreaders.
The map elucidates the relationship between tension in the suspension system and the axis of rotation between anchors in two-anchor systems, as well as the relative position of the center of mass, indicating the radius of containment of the load, “metacentric height” and inherent stability.
The map will indicate how funicular lines, ridgelines or other features redirect tension to alter the geometry of the suspension system and contribute to the shape of the sling.
The map will indicate the number and spatial relationship of anchors used for the configuration. It will show the angles at which tension is placed on each anchor and indicate the horizontal force experienced, thus advising how suitable they are for the probable types of anchor available in the intended setting of use.
The map may be used to elucidate the changing strength of tension in lines as they accumulate the weight of the load, values that factor into shape calculations such as the Finite Element Method.
Material PropertiesA successful design process will evaluate the role that material properties play in the structural performance of the device and prescribe arrangements needed for component parts to reliably meet requirements.
The design calls for the suspension system to suspend the load at a prescribed elevation, maintain boundaries of the sling in a certain shape, and convey tension from the sling to the anchors. Performance in these roles will be affected by stretch in the lines when loaded, and therefor mitigating this factor must be balanced against the weight, cost and shape of the materials chosen. For example, flat polypropylene webbing is inexpensive and easy to assemble, but succumbs to considerable stretch when spanning long distances, allowing the load to sag, while Spectra has high strength and very little stretch, but is more costly, and the reduced sizes utilized may present challenges to the assembly process.
Similarly, the sling is intended to maintain a certain geometry and provide a quality of interaction with the load, referred to as load service or user experience. The successful pattern prescribes how the properties inherent in each material piece of the hammock body will be arranged to fulfill these roles. Certain fabrics may stretch in one dimension only (two-way), while others stretch in both dimensions (four-way), while yet others allow very little stretch at all. Some types, while not stretching, may easily allow deformation of panel shapes under shape-wise shear forces, while others do not. An ensemble of individual cords arranged in a parallel array provides high strength and dimensional stability parallel to their length, but no ability whatsoever to maintain position or shape perpendicular to it, and, of course, rigid slats offer a beam-like structure, but don't comfortably conform to the contours of their contents. The relative slipperiness or friction presented by surface finishes of various materials will affect the degree to which the mass of the load remains as placed in the sling or slides or shifts to pool in the lowest point of the sling.
6 Material Patterns & AssemblyFinally, implementation of a new hammock design culminates with the selection of specific materials, generation of patterns with dimensions, and physical assembly. The Invention concept may be embodied in a diversity of configurations, using a variety of materials and manufacturing modes, therefor this section seeks to elucidate the principles governing the physical elements employed rather than prescribe specific methods of manufacture.
Materials & Attachment/Assembly MethodsA general plan for the configuration of the device and type of material used will be inherent in the conception of the product, being integral to the performance of the device. Once exact parameters are established for the design, a person skilled in the art or similar industrial trades will easily determine the necessary steps and techniques for a particular construction. The materials chosen and their arrangement will indicate the assembly methods to be used.
For example, methods of fastening suspension lines for connections or forming of features may include tying, splicing, weaving, stitching, bar-tacking, shackling, or other means, and will depend on the material used.
Funicular lines, when included, will most naturally be composed of the same, or similar material as the main suspension lines, and fastened by similar methods, but any variation could be utilized.
Components of the sling will be assembled by a means suitable for the particular material, the required performance, and the manufacturing methods. The chosen method may be to weave, knit, stitch, ultrasonically weld, glue, lash, or some other means of attachment.
Pattern Making SchemePattern Development is the last facet of the design process. Implementation requires a scheme for how pieces of stock materials will be assembled to form the three dimensional geometry of the sling. The scheme provides a plan for how component parts may be dimensioned, and an assembly sequence prescribed. Different schemes may be used to produce a given hammock example, with each embodying the functional structure of the invention in its own way. While the scheme fundamentally provides for the shape of the device, it must also account for how the material properties will perform structurally and provide the required load service, or user experience.
In some examples, the scheme for assembly may be clearly dictated by the intended use and material composition described in initial product concept. In other hammock examples, especially those with fabric hammock bodies, a number of possibilities may be present, which must be evaluated.
Hammock slings are generally constructed of flat material, and while the simplest bridge hammock bed can be formed from a single continuous piece of fabric, the compound curves and potentially complex 3-dimensional geometries cannot be formed from a single piece. Also, some examples call for materials of different types, or have specialized functional requirements of the load pocket. In these cases, a scheme for combining variously shaped component pieces must be contrived.
Pattern development follows techniques similar to those used for pattern flattening in the garment industry, where the desired 3D form is unfolded to develop the 2D shapes. With the objective of minimizing part counts and seams, single cuts of material are assigned to cover as much area or as many sides as practical, beginning with planar surfaces, even if mildly deformed, and wrapping around simple curves or corners to box in the volume. Significantly cupped surfaces with compound curves, or where planes join irregular contours—must be developed from multiple pieces tiled together, or possibly sculpted by means of folds or laps in the fabric, to form strategically placed darts. The outcome is a set of explicit shapes and dimensions that produces the intended geometry when assembled.
Shapes may be approximated when tiling of sling contours results in an overly complicated pattern. By taking advantage of fabric properties like stretch and shear, along with judicious selection and arrangement of materials, a simplified pattern may be produced that allows the assembled sling to flex and conform to the user in a satisfactory way.
There may be multiple approaches available for patterning a given sling design. The most suitable scheme will best serve the desired styling, material selection, structural performance and assembly methods for each example.
The design process describes regions of the sling serving particular functions, such as the seat back support surface or integrated stuff sack, while the pattern scheme prescribes material pieces to build the shape of the sling. The pattern scheme may map a given functional region onto multiple material piece whose finished assembly performs the designated function, or it may map several functional regions onto one material piece. The shape of the pattern pieces may not coincide at all with the shape of the functional region.
The shaped side panel is a key feature of the embodiment of the invention and represents a function more than merely a geometric shape. The shaped side panels may be patterned using the shape described in the design process or may be provided as the sum of multiple pieces cooperating to produce the required geometry and functional structure or may be provided as one portion of a piece providing multiple functional regions.
In addition to shape, the pattern scheme must accommodate the structural requirements of the assembly, as described above. The properties of the materials used and their arrangement within the assembly serve to maintain the designed shape of the device while conveying tension forces from the load through the sling to the suspension system, and on to the anchors. For many examples, the pattern must prescribe the orientation of the material for specific portions of the sling. Tension forces within the sling will typically be oriented in multiple directions, as indicated by the force map. Many fabric materials deform under strain in some orientations, and while a degree of stretch and shear can be used to advantage for simplifying a pattern and aiding user comfort, it may compromise structural performance if not strategically arranged.
DimensionsAs part of the Pattern, the Dimension Scheme prescribes how measurements for individual components of the hammock are taken.
Dimensions fall within the sequence of dependencies governing steps of the design, as described above. The alignment of cross-sections or associated dimensions will be dictated by the structural and material needs of the paneling scheme, which prescribed division of areas into panel parts, and orientation of materials according to their properties. For example, cross sections in 3D space may all be aligned vertically in one example, such as the bed, producing a parallel array of dimensions for the flat pattern. Alternately, cross sections may be aligned normal to angles of the supporting surfaces, which may vary along the length of the device, such as in a chair. This may produce a flat pattern comprised of a mosaic of irregular polygons whose combined area results in the needed panel shape.
Overall dimensions of the device taken along a certain path may be divided between separate parts, depending on the scheme. For example, a pattern for the sling may be divided lengthwise of the device, where the load support surfaces, such as seat or bed panels, would be one long piece, and each side panel be a separate full piece, or the pattern may be divided crossways, with part of load support surface being contiguous with parts of each side panel.
Most examples are symmetrical about a centerline, therefore in practice, dimensioning of pieces for cutting propagates from a center datum, defining the profile by mirroring half width dimensions.
Dimensions may be derived using a variety of schemes, in like manner to the pattern, and in cooperation with it. In one method, dimensions for the fabric sling portion found in many examples may be obtained by finding the path length of cross sections taken at regular intervals along the length of the hammock.
Previous steps of the design process established the geometric proportions of the device. These parameters include the overall dimensions of the suspension system, with starting and ending angles of suspension lines and the size and position of any spreaders; the position of the load relative to the suspension system, yielding the depth of the sling below the suspension lines; the distribution of the load, resulting in the curvature and lateral deflection of suspension lines needed to support the load; and the size and posture of load, including lateral profile and depth contour of the bed, seat or load support surfaces. The shaped side panels are then found to be the area spanning from the lateral boundary of the load support surface to the curvature of the suspension lines. Suitable design methods may employ these parameters to produce a series of data points defining the contours of the device in three dimensional space.
A cross section of the load support surface at the bottom of the sling will produce a curve of a certain shape and length, and a cross section of each side panel is found as the length of the span between a point on its lower edge, where it meets the boundary of the load support surface, and a corresponding point on the suspension line, noting that this span will typically be straight, since there is no deflection from contact with the load. Then the path length of the cross section of the sling is the sum of the lengths of the load support surface and distance of the span of each side panel. We note that each cross section will produce a unique length, as the relationships between all above contours will vary along the length of the device.
Many hammock examples could require pattern pieces whose shapes are irregular and cannot be defined with standard geometric figures, therefor pattern dimensioning would require sets of data. These may be generated from multiple cross sections of the sling taken at intervals along its length.
A first example of a scheme is seen in the pattern for the sling of the hammock bed of this disclosure. Although the bed trough is narrow at one end and considerably wider and taller at other, its 3-dimensional shape is simple, and can ideally be made from one large, flat piece of fabric to form both shaped side panels and the load supporting bed surface between them. The fabric stretches from one suspension line, down under the load and back up to the other line. The addition of a second panel at the head end is optional.
The structural configuration is equally simple, with all the load forces in the side panels being oriented perpendicular to the length of the device in a generally up and down direction, so the pattern is arranged with the fabric grain also perpendicular to the length of the device. Dimensions for the pattern are simply taken as the path length of cross sections at intervals along the length of the sling—from one suspension line, down under the load and back up to the other line.
A second example is seen in the fabric lounge chair of this disclosure, seen in
Scheme 1—In one scheme, the pattern utilizes the same regions described by the design process; the seat pocket is formed of panels generally dividing the sling from side to side into three parts—a left side panel, the central seating surface, and a right side panel. The elevation contour of seat surface is established by the profile of the bottom boundary of the side panels, such that a single piece forms the seat bottom portion, then angles upwards to form the seat back portion. If the sling design were to be extended to support the feet of the user, each of the three panels would be extended in length with a suitably shaped addition.
Dimensions for the panels will generally follow the shapes defined in the design process. Two seams connecting the three panels run the length of the sling from end to end and will be at the side of the user. They must withstand all the strain of supporting the load transmitted from side to side of the sling. It is expected that fabric side panels with a simple rectangular weave will experience some deformation, since tension forces along the length of the side panels are not parallel but change orientation from end to end.
Scheme 2—In another scheme the sling body is divided into three regions from top to bottom, with panels extending side to side from one suspension line to the other. The top panel forms the seat back surface and upper portions of the shaped side panels, a bottom panel forms the seat bottom surface and lower portions of the shaped side panels, and a middle panel accommodates the transition between the two at the turn of the hip. If the sling design were extended down to support the user's lower legs and feet, a fourth crosswise section would be added in similar fashion.
The shape of the sling is approximated—although a strictly geometric construction using only three flat panels would have distinct corners or ridges, in practice, the fabrics that are commonly used will flex enough for the sling to conform to the smoothly curving body shape of the user.
The grain of fabric in each panel is oriented to align with the strain path between suspension lines. Tension developed in the side portions of each panel will be generally normal to the area of the seating surface it supports, such that when all three panels are assembled, the tension map will show a radial pattern in the side panels, with a predominance of forces converging on a portion of the suspension lines centered above the hips. The fabric panel pieces are cut so that the grain coincides with this radial pattern once assembled.
Dimensions for the pattern can be taken along the same side-to-side strain paths, which are the path lengths along cross sections taken with the same radial pattern described. This produces a flattened pattern with polygonal shapes that are widest across the central portions of the seat surfaces and narrowing toward the junction with the suspension lines.
Seams joining the back panel to the hip, and hip panel to the seat, being oriented across the device from side to side, must endure a certain amount of longitudinal strain and conformational forces in the side portions, but these are much less than the weight of the load.
A third example is provided by the wooden slat chair of this disclosure shown in
The shaped side panel portions of the sling may be configured in multiple ways. A first option, not shown, might be to employ suitably shaped panels of solid fabric, much like those slings that are entirely composed of fabric. A second option is for an arrangement of individual cords connecting each slat to the suspension line, such that each cord functions separately and as if in parallel, although the actual arrangement will have a radial pattern matching the strain paths, as described above. A third option utilizes an engineered network of cordage. This network would be comprised of individual strands, oriented diagonally forwards and rearwards, being connected where they intersect to form a diamond shaped grid pattern with a shape and structure suitable to position the seat surface and withstand the varying tension forces.
Claims
1. A bridge hammock system for suspending at least one load between first and second anchor points, the hammock system comprising:
- a suspension system comprising at least one suspension line and defining a first end adapted to be connected to the first anchor point and a second end adapted to be connected to the second anchor point; and
- a load bearing sling having at least one load support surface region and at least one side panel region; wherein
- the suspension system defines a curve such that the first end of the suspension system defines a first slope and the second end of the suspension system defines a second slope;
- the at least one side panel region supports the at least one load support surface region from the suspension system;
- the at least one side panel region is sized and shaped to integrate the curve of the suspension system with the load bearing surface region such that a collective slope of the suspension system is greater than zero, tension forces on the first end of the suspension system are substantially upwardly directed, and tension forces on the second end of the suspension system are at least one of substantially laterally and substantially downwardly directed; and
- the at least one load is arranged on the at least one load support surface region.
2. A bridge hammock system as recited in claim 1, in which the desired shape and orientation of the at least one load support surface region is adapted to support a human occupant in a generally horizontal orientation.
3. A bridge hammock system as recited in claim 1, in which the desired shape and orientation of the at least one load support surface portion is adapted to support a human occupant in a sitting or reclining posture.
4. A bridge hammock system as recited in claim 1, further comprising at least one spreader configured to engage the suspension system.
5. A bridge hammock system as recited in claim 1, further comprising a plurality of spreaders configured to engage the suspension system.
6. A bridge hammock system as recited in claim 3, further comprising at least one rigid member defining the at least one load support surface portion.
7. A bridge hammock system as recited in claim 1, in which the suspension system comprises a single suspension line configured and arranged to support the at least one side panel region to suspend the at least one load bearing surface portion from the single suspension line.
8. A bridge hammock system as recited in claim 1, further comprising a soft spreader engaging at least a portion of the load bearing sling.
9. A bridge hammock system as recited in claim 1, in which the collective slope of the suspension system is greater than approximately 10 degrees.
10. A bridge hammock system as recited in claim 1, in which the hammock system operates in a hammock mode and in a tent mode, wherein:
- in the hammock mode, at least a portion of the load bearing sling is suspended above the ground such that the load is supported above the ground;
- in the tent mode, at least a portion of the load bearing sling is arranged to define a shelter for a person sitting on the ground; and
- when the hammock system operates in the tent mode, a first portion of the load bearing sling adjacent to the first end of the suspension system is higher and wider than a second portion of the load bearing sling adjacent to the second end of the suspension system.
11. A bridge hammock system as recited in claim 10, further comprising at least a first elongate member and a second elongate member, where the first and second elongate members are configured in:
- a first mode in which the first and second elongate members are separately arranged to engage the suspension system; and
- a second mode in which the first elongate member is connected to the second elongate member to form a riser pole having an effective length that is greater than lengths of either of the first and second elongate members.
12. A method for suspending at least one load between at least first and second anchor points, the method comprising the steps of:
- providing a suspension system comprising at least one suspension line and defining a first end and a second end;
- connecting the first end to the first anchor point;
- connecting the second end to the second anchor point; and
- providing a load bearing sling having at least one load support surface region and at least one side panel region;
- operatively connecting the load bearing sling to the suspension system such that the suspension system defines a curve, where the first end of the suspension system defines a first slope and the second end of the suspension system defines a second slope, and the at least one side panel region supports the at least one load support surface region from the suspension system;
- sizing and shaping the at least one side panel region to integrate the curve of the suspension system with the load bearing surface region such that the load bearing surface region defines a desired position and orientation of the load, a collective slope of the suspension system is greater than zero, tension forces on the upper attachment portion are substantially upwardly directed, and tension forces on the lower attachment portion are at least one of substantially laterally and substantially downwardly directed; and
- arranging the at least one load on the at least one load support surface region at a position below the first anchor point and above the second anchor point.
13. A bridge hammock system for suspending at least one load from two or more anchor points, the hammock system comprising:
- a suspension system comprising at least one suspension line and defining a first end adapted to be connected to the first anchor point and a second end adapted to be connected to the second anchor point; and
- a load bearing sling having a plurality of load support surface regions and at least one side panel region; wherein
- the suspension system defines a curve such that the first end of the suspension system defines a first slope and the second end of the suspension system defines a second slope;
- the at least one side panel region supports the at least one load support surface region from the suspension system;
- the at least one side panel region is sized and shaped to integrate the curve of the suspension system with the load bearing surface region such that a collective slope of the suspension system is greater than zero, tension forces on the first end of the suspension system are substantially upwardly directed, and tension forces on the second end of the suspension system are at least one of substantially laterally and substantially downwardly directed; and
- the at least one load is arranged on the at least one of the plurality of load support surface regions.
14. A bridge hammock system as recited in claim 13, in which at least one of the plurality of load supporting surface regions is configured to support an animal.
15. A bridge hammock system as recited in claim 13, in which at least one of the plurality of load supporting surface regions is configured to support a plant.
Type: Application
Filed: Jul 27, 2021
Publication Date: Jan 18, 2024
Inventor: Paul Steven Mosman (Anacortes, WA)
Application Number: 18/007,030
