Portable Back Rest

Abstract

A portable back rest is provided having a U-shaped frame formed from two vertical segments joined with a horizontal segment. Points on the end of each vertical segment are adapted to pierce and become submerged in soil or sand and hold the frame upright where the horizontal segment will support fabric such as a towel as a back support. Fins may be positioned adjacent the points on the ends of the vertical segments to further stabilize their engagement with soil or sand and provide a contact point for a foot during insertion.

Description

FIELD OF THE INVENTION

This Application claims priority to U.S. Provisional Patent Application Ser. No. 62/165,722 filed on May 22, 2015 which is incorporated herein in its entirety by this reference thereto.

The present device relates to seats and back rests. More particularly, the disclosed device, creates a lightweight and portable back rest configured to support the upright positioning of a seated user, which is adapted for easy engagement with soil or sand.

BACKGROUND OF THE INVENTION

A large number of the outdoor activity and event venues, such as picnic sites, beaches and camping grounds, do not offer adequate seating or in many cases any seating for visitors. While there is frequently plenty of space in parks and other recreation areas for visitors to sit or lay directly upon the ground, there generally is a lack of upright seating for such visitors. Consequently, visitors to such venues, for example the beach, are left to their own devices should they desire to have a back support and upright seating to as to be able to sit and enjoy the view during a visit.

Employing a picnic blanket or towel upon the grass of a park or the sand at the beach helps keep the user clean and separated from the soil or sand on the ground. However, such planar covers only allow a user placing them on the ground to lay upon them face down or face up. As such, the ground-positioning of such towels and blankets offer no upright or vertical support and thus will not provided comfortable support for the user to lounge or rest in an upright or seated position while relaxing, sun bathing, talking or eating. While a prone position may be sufficient for a portion the time spent visiting an outdoor venue, visitors wishing to view other people, the water or surf, and the surrounding area or activity, are unable to easily and comfortably do so when laying flat on the ground or sand.

In attempting a solution to this problem, users may generally shop to pick from an array of portable chairs. Such chairs are generally composed of a jointed seat back and a bottom for sitting upon. In many instances such chairs may have longer or shorter legs to hold the user elevated a distance above the support surface or ground while seated. A multitude of such outdoor seating devices have been developed to allow the user to sit upright during outdoor visits to their favored recreational areas.

Such chairs are also generally formed of textile fabric or webbing which is operatively engaged to the framework which is formed of metal or plastic. In some modes of conventional portable chairs, mechanisms are included in the framework which allow the user to select the angle between the chair back and a generally horizontally deployed bottom or seat. This chair back is adapted to support their upper body in a variety of angled positions relative to the soil or sand support surface.

However, the bulk and size required for the framework and associated mechanisms of such portable chairs which enables them to support the weight of the user, often renders these portable chairs heavy or cumbersome to transport. Additionally, such chairs tend to corrode and invariably the fabric engaged therewith will wear from use. As a result, these fabric covered chairs and seats are usually rendered inoperable over time by the failure of the support fabric engaged to the framework.

As such, there is a specific and unmet need for a lightweight and simple portable back rest and support device, which is easily transported. Such a device should provide the user with supported positioning of their back, in an upright position, with their body concurrently separated from the underlying soil or sand during use. Such a device in addition to being light weight, should be easily broken down into smaller components which are easily assembled to allow for easy and compact transport. Finally such a device should enable the user or the provider to outfit the seating support with their own fabric or textile supporting surfaces, to allow for customization or employment of favored decorative towels and blankets if desired, as well as providing an easily changed fabric or textile support surface and avoid the obsolescence of conventional chairs which occurs when the permanently engaged fabric become inoperable.

The forgoing examples of related art and limitation related therewith are intended to be illustrative and not exclusive, and they do not imply any limitations on the invention described and claimed herein. Various limitations of the related art will become apparent to those skilled in the art upon a reading and understanding of the specification below and the accompanying drawings.

OBJECTS OF THE INVENTION

It is an object of the present invention to provide a seat back support, which requires minimal skeletal support through the employment of distal ends adapted for insertion into loose ground, and a frame adapted to engage with a towel or blanket of choice, to provide back support to the user.

It is an additional object for the device to allow the user to employ their own towel or textile fabric as the back support which is easily yet securely engaged to the supporting structure.

Another object of the invention is the provision of such a back support which is formed of easily disengaged components to allow for easy and compact transport, but which can be configured to remain connected in a disengaged state.

These and other objects, features, and advantages of the present invention, as well as the advantages thereof over existing prior art, which will become apparent from the description to follow, are accomplished by the improvements described in this specification and hereinafter described in the following detailed description which fully discloses the invention, but should not be considered as placing limitations thereon.

SUMMARY OF THE INVENTION

In accordance with the purposes of the present invention, as embodied and broadly described herein, the present invention provides a device configured as a portable back rest support.

The device includes a framework formed of a solid or preferably a hollow tubular frame having an axial passage running therethrough. The framework may be formed using tubular members with bends at only two points along the framework, to thereby form two opposing vertical segments connected by a horizontal cross member section.

The distal ends of both vertical segments are adapted for secure but easy engagement with underlying soil or sand, and so engaged will support the horizontal segment. In an assembled configuration, all the included segments may have axes which are coplanar with an axial passageway running the length of the assembled frame. So assembled, the vertical segments are congruent and symmetric about the middle segment bisecting plane.

In all preferred modes of the device, the assembled tubular frame employs a pair of vertical segments, each having a respective distal end which is configured with a point or spear engaged thereon. The point allows for easy device penetration into loose ground or sand. Formation of the pointed ends for the assembled frame can be accomplished by angle cutting, crimping, cold forming or through affixing a conical pointed-end component on each distal end.

The tubular structure may have a uniform outer diameter of between 0.125 and 1 inches, and can be formed from engageable sections of tubing having rectangular, circular or geometrical cross sections. Additionally, the tubular vertical segments, and horizontal segment can range between 10 to 48 inches, and 10 to 24 inches long respectively, depending upon the size of the intended occupant.

At an engagement point of each of two ends of the horizontal member to one end of the vertical members, the angle should be between 80 to 110 degrees with a current favored mode being substantially 90 degrees. As noted this angled engagement may be accomplished by forming the entire frame of a single member and bending the single member to form the corners, or more preferably, forming the frame from a plurality of elongated member portions which connect at engageable corner components adapted for a frictional or other removable engagement with the horizontal segment and two vertical segments. Forming the framework of the device from multiple engageable components allows it to be dissembled and formed to a smaller storage configuration.

In a particularly preferred mode of the device, the pointed ends positioned at the distal ends of each vertical segment will include adjacently positionable stabilizing projections extending radially therefrom. Currently, such projections are provided by employing between 1 to 5 stabilization fins which project radially from and around the axis of each vertical member and which taper toward the pointed end upon the vertical members. These fins are employable for both pushing the vertical member into the sand or soil by pushing upon them with a foot. Once engaged with the soil or sand, the fins also help secure the ends to a fixed position in the soil or sand.

So engaged with soil or sand, the preferred radially projecting fins provide for increased rigidity of the assembled frame by preventing traverse movement of the distal ends. Further they provide resistance to disengagement from the soil or sand during use when the user may be leaning upon the textile fabric the vertical members support. The stabilization fins in a current preferred mode or of a length of between 0.25 and 5 inches and project radially from the circumference of the vertical member between 0.25 and 5 inches.

To employ the device herein and position it to an as-used position engaged with underlying soil or sand, the user will assemble the components if formed of multiple components. With the frame assembled, the user will force downward on the tubular frame vertical sections using their hands and body weight, or if fins are engaged, by stepping on the rear of the fins to force the vertical member into the soil or sand. This force causes a piercing of the sand or soil by the pointed distal ends of each vertically disposed member. The force is continued until the vertical members and if employed, the radially projecting fins are buried below ground level of the soil or sand.

If fabric is not pre-engaged to the vertically disposed members, once the frame is in an engaged position, with soil or sand covering the pointed ends, the user may roll or tie a towel over the horizontal segment of the frame and drape the towel down between the vertical exposed sections of the tubular frame segments, and onto the loose ground. A frictional engagement surface or textile engagement surface may be optionally positioned upon the surface of the horizontal segment. Further, draping a towel or blanket so that the user is sitting upon both ends underneath the seat of the user, will create a taught backrest to allow the user to lounge in comfort.

In another preferred mode of the device the sections forming the tubular structure may be disengageable for easy packing, storage, and transportation. In this mode, the device should contain one or a combination of rigid, temporary segment coupling means such as mating threads, pins, spring pins, slots, interference fits, snaps, clasps, collars, bands or ties.

To prevent tubular structure segment loss, and to increase the rigidity of the assembled frame, this mode of the device may optionally employ a joining string or elastic band, or a combination thereof, which is engaged at both ends of the assembled frame and communicates through an axial passage running the length of the frame and any other permanent, nonrigid segment joints or flexible or slip fit tubes.

Additionally, in other modes of the device, one or more clips on the vertically disposed members of the tubular frame can be positioned to temporarily engage with a towel, or blanket, or other textile to the ground-engaged frame of the device. The clip in this mode of the device can, for example, include one or a combination of clips from a group including thumb clips, clasps, bungee straps, clinch straps, bands, hook and loop fasteners or ties.

The tubular structure in all modes should preferably be composed of a durable, lightweight material such as aluminum, or plastic if sufficiently strong. However, it might also be formed of one or a combination of other materials from a group of materials including wood, steel, carbon fiber, fiberglass, resin or polymeric materials. Additionally, a horizontal splat can be made of any durable, sun-resistant, flexible woven or non-woven material. Such may be formed of one or a combination of textile materials including nylon, cotton, polyester, denim, plastic, synthetic yarns, or wool.

With respect to the above description, before explaining at least one preferred embodiment of the herein disclosed invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangement of the components in the following description or illustrated in the drawings. The device herein described and disclosed in the various modes and combinations is also capable of other embodiments and of being practiced and carried out in various ways which will be obvious to those skilled in the art. Any such alternative configuration as would occur to those skilled in the art is considered within the scope of this patent. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for designing of other powder and pill storage and dispensing products for carrying out the several purposes of the present disclosed device. It is important, therefore, that the claims be regarded as including such equivalent construction and methodology insofar as they do not depart from the spirit and scope of the present invention.

BRIEF DESCRIPTION OF DRAWING FIGURES

The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate some, but not the only nor exclusive examples of embodiments and/or features of the disclosed device. It is intended that the embodiments and figures disclosed herein are to be considered illustrative of the invention herein, rather than limiting in any fashion. In the drawings:

FIG. 1 depicts a front view of a mode of the device in an as-used positioning with distal ends of both vertical members, engaged with soil or sand.

FIG. 2 shows a disassembled front view of the device showing a mode of the frame with separable components and an elastic member running through an axial passage extending the length of the frame.

FIG. 2A depicts a perspective view of the device in an as-used positioning, with fins radially projecting adjacent distal ends operatively engaged below ground level of the underlying soil or sand.

FIG. 3 displays a perspective view of a mode of the device which includes removably engaged fabric section for back support.

FIG. 4 depicts a perspective view of another mode of the device having clips projecting from the assembled frame for engagement of the textile or other flexible supporting fabric.

FIG. 5 shows a mode of the fins which may be slidably engaged upon the frame, and adjusted in positioning.

FIG. 6 depicts pointed ends which may be operatively engaged with the distal ends of both vertical members and showing a flexible elastic member connected thereto which may run through the axial passageway running through the assembled frame to bias the components to hold engagement.

DETAILED DESCRIPTION OF THE INVENTION

Now referring to the drawings in FIGS. 1-6, wherein similar components are identified by like reference numerals, there is seen in FIG. 1 the device 10 configured to an assembled configuration and ready for use as a portable back rest. In the depicted mode of FIG. 1, the device 10 includes a solid or hollow tubular frame 12, which may be formed from a single member which is bent at two corners, or otherwise formed of segments which are operatively engaged at corners. In this assembled configuration, the frame 12 is substantially a U-shape and has opposing and coplanar opposing vertical segments 22 which support a horizontal segment 22 a distance above the ground or soil. By substantially U-shaped is meant that the vertical segments 22 can be parallel and engaged at a substantially right angle with the horizontal segment 22, or may run at an angle toward or away from each other in the direction toward their respective intersection or engagement with the horizontal segment 22. As noted this angle of engagement can be between 80 to 110 degrees.

The horizontal segment 20 and the opposing vertical segments 22 with the frame 12 when formed to an assembled or as-used mode, such as in FIGS. 1, 2a, and 3-4 are all preferably all coplanar to allow for proper positioning and support of the towel or blanket or other flexible sheet over the horizontal segment 22 where it may be supported thereby or may be held in position by an engagement surface 21 positioned on the horizontal segment 22. Such an engagement surface for example can be hooked fabric or a gnarled surface on the horizontal segment to resist slippage of the fabric support 16.

In all preferred modes of the device 10, the vertical segments 22 have distal ends which are pointed or have a point 23 thereon, either formed or engaged, to allow for easy penetration thereof into loose soil or sand 18.

The frame 12 in current preferred modes has a substantially uniform outer diameter of between 0.125 and 1 inches. It may be formed with circular or rectangular or geometrical cross sections. Additionally, the vertical segments 22, may be between 10 to 48 inches in total length from points 23 to engagement with the horizontal segment 20, and the horizontal segments 20, 3 to 36 inches in length. A currently preferred angle between each of the vertical segments 22 at their respective intersection with the horizontal segment 20, thereby forming the U-shaped frame 14, is between 80 and 110 degrees. When using fittings for a removable engagement therebetween, a substantially 90 degree angle has been found to form a strong and stable structure when engaged to sand or soil. By substantially 90 degrees is meant exactly 90 degrees or plus or minus 5 degree from 90 degrees.

Each vertical segment 22 preferably includes between 1 and 5 stabilization fins 14 positioned at or adjacent the distal ends of the vertical segments 22 where the points 23 are positioned. The fins 14 provided for increased resistance to disengagement from the soil or sand while supporting a user and help prevent the vertical segments from tipping when the user leans upon the towel or fabric support 16.

The stabilization fins 14 in a current preferred mode are of a length of 0.25 and 5 inches, extend radially from the center axis and exterior surface of the vertical segments 22 of the formed tubular frame 12. The fins 14 may be positioned at or adjacent the distal ends of the vertical segments 22 as noted, or in an adjustable mode, using removably engageable fins 14 such as in FIG. 5, which allow for adjusting the fin 14 distance from the points 23, to adjust for harder or softer dirt or sand and adjust the depth of insertion of the ends of the vertical segments. Further, it is preferred that the fins 14 extend a distance from the vertical segment 22 with a fin edge 15 (FIG. 5) that runs perpendicular or at a slight incline to the axis of the vertical segment 22. The forms the fin edge 15 to define a foot-engagement surface, so the user may step upon the fin edge 15 during engagement of the points 23, fins 14 and vertical segment 22 in the soil or sand. As noted below, the fins 14 can also be engaged adjustably, to allow for more or less penetration into the soil or sand, which allows for a spacing of the fins 14 from the pint 23 and a more secure support resistant to tilting.

To employ the device 10 herein, a user will force the vertical segments 22 downward thereby piercing the loose ground 18 with the points 23 positioned at the distal ends of the vertical segments 22. The distal ends are forced below ground lever until the stabilization fins 14 are partially or preferably fully buried. As noted, the fin edge 15 of each fin 14 can also allow for a foot engagement to help force the vertical segments 22 into the sand or soil.

For a device 10 configured without a permanent or removably engaged flexible fabric support 16, the user will position a fabric support 16 such as a towel or blanket or similar planar flexible support surface held over or upon over the horizontal segment 20 of the frame 12. The towel or blanket ends may be draped down and over or in-between the vertical segments 22, and onto the loose ground 18. Thereafter a user sitting on the two ends of the towel 18 or blanket providing the fabric support 16, will secure them to the ground and leaning thereon creates a taught backrest to allow the user to lounge in comfort.

In addition to, or in place of the towel 18 or blanket, the user may choose to employ one or a combination of soft collapsible and portable items including but not limited to: cloths, clothing, bags, sheets or nets.

In another preferred mode of the device 10, per FIG. 2, the tubular frame 12 can be formed of the vertical segments 22 and a horizontal segment 20 which are disengageable for easy packing and transportation. In this mode, the device 10 should contain one or a combination of rigid, temporary segment coupling means such as mating threads, pins, spring pins, slots, interference fits, snaps, clasps, bands, ties or slidably engageable fittings at the corners 29. Or the corners 29 may be portions of either the ends of the horizontal segment 20 or the upper ends of the vertical segments 22 which are bent to a curve forming the engageable corner 29. In all modes the adjacent vertical segment 22 and horizontal segment 20 will be formed to connect in a removable engagement as noted. To prevent segment loss in a disassembled mode of the frame 12, optionally a flexible and preferably elastic joining member 24 may be employed which is axially threaded through the continuous axial passageway formed between all the connecting components.

This joining member 24 can be engaged for instance to a point 23 component such as in FIG. 6, which will connect to the ends of the joining member 24 by crimping thereto, or engaging it with knots to an aperture in the point 23 component. If the length of an elastic joining member 24 is less than that of the axial passageway through the formed and assembled frame 12, it will impart a biasing force to the assembled components of the formed frame 12 to help hold it assembled.

As shown in FIG. 3, a permanent or removable horizontal splat 26 may be engaged to the vertical segments 22. As depicted a collar is formed on both ends of the splat 26 through which vertical segments 22 are inserted.

In FIG. 4 is shown a mode of the device 10 employing clips 28 positioned on the formed frame 12 such may also be employed to temporarily affix a towel 18 or blanket or the like to the device 10.

As noted, FIG. 5 depicts an adjustably positionable fin component 31 which is slidably engageable in position upon the vertical segments 22. The fins 14 extend radially around a collar 33 sized to slidably engage upon the exterior of the vertical segments 22. The fin component 31 and fins 14 may be slid closer to or further from the points 23 to allow for a deeper or shallower positioning of the fins 14 in the soil or sand. A releasable connector 35, such as a set screw or an aperture which will engage depressible balls on each vertical segment 22, allows the collar 33 to be positioned, and then held in that position by setting the connector 35 such as a set screw.

FIG. 6 depicts points 23 which may be operatively engaged with the distal ends of both vertical members 22 and showing a flexible elastic member 24 connected thereto by a connector such as a crimp 37. A recess 39 in the exterior circumference would be sided for slidable engagement within the axial passage at the distal ends of the vertical members 22.

As noted, the frame 12 should preferably be composed of a durable, lightweight material such as aluminum, but can alternatively be made of one or a combination of materials in a list including but not limited to: wood, steel, carbon fiber, fiberglass, resin or plastic. In either a single pieced component or formed of multiple components, an axial passage running the length of the frame 12 will allow for communication of the flexible member 24 therethrough and if elastic, a biased compressive engagement of multiple components if so formed.

As noted, any of the different configurations and components can be employed with any other configuration or component shown and described herein. Additionally, while the present invention has been described herein with reference to particular embodiments thereof and steps in the method of production, a latitude of modifications, various changes and substitutions are intended in the foregoing disclosures, it will be appreciated that in some instance some features, or configurations, or steps in formation of the invention could be employed without a corresponding use of other features without departing from the scope of the invention as set forth in the following claims. All such changes, alternations and modifications as would occur to those skilled in the art are considered to be within the scope of this invention as broadly defined in the appended claims.

Further, the purpose of any abstract of this specification is to enable the U.S. Patent and Trademark Office, the public generally, and especially the scientists, engineers, and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. Any such abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting, as to the scope of the invention in any way.

Claims

1. A portable back rest apparatus, comprising:

a U-shaped frame having two vertical segments joined a respective first ends to opposing ends of a horizontal segment extending therebetween;

a pair of points, one each of said pair of points positioned at a respective distal end of one of said two vertical segments opposite a respective said first end;

said frame positionable to an engaged position extending generally upright from a support surface of soil or sand, with said pair of points in submerged positions therein; and

said horizontal segment adapted to support a middle portion of a fabric support elevated above said support surface, with at least one end portion of said fabric support positioned upon said support surface for a user to sit upon.

2. The portable back rest apparatus of claim 1, additionally comprising:

at least one fin positioned at or adjacent each said distal end of each of said two vertical segments, each said fin extending in a direction away from an engagement with an exterior surface of said vertical segment.

3. The portable back rest apparatus of claim 2, additionally comprising:

each said fin having a fin edge extending away from said vertical segment, said vertical edge defining a foot engagement position for a foot of said user, whereby a user may employ force from their foot to force said point on each respective vertical segment to said submerged positions.

4. The portable back rest apparatus of claim 1, additionally comprising:

said frame formed of said two vertical segments each in a removable engagement at said respective first ends, with said opposing ends of said horizontal segment.

5. The portable back rest apparatus of claim 2, additionally comprising:

said frame formed of said two vertical segments each in a removable engagement at said respective first ends, with said opposing ends of said horizontal segment.

6. The portable back rest apparatus of claim 3, additionally comprising:

said frame formed of said two vertical segments each in a removable engagement at said respective first ends, with said opposing ends of said horizontal segment.

7. The portable back rest apparatus of claim 4, additionally comprising:

a flexible elastic member extending through an axial passage of said frame running through each of said two vertical segments and said horizontal segment;

opposing ends of said elastic member connected at or adjacent respective said distal ends said pair of vertical segments; and

said flexible elastic member imparting a compressive bias to said two vertical segments in their removable engagement with said horizontal segment.

8. The portable back rest apparatus of claim 5, additionally comprising:

a flexible elastic member extending through an axial passage of said frame running through each of said two vertical segments and said horizontal segment;

opposing ends of said elastic member connected at or adjacent respective said distal ends said pair of vertical segments; and

said flexible elastic member imparting a compressive bias to said two vertical segments in their removable engagement with said horizontal segment.

9. The portable back rest apparatus of claim 6, additionally comprising:

a flexible elastic member extending through an axial passage of said frame running through each of said two vertical segments and said horizontal segment;

opposing ends of said elastic member connected at or adjacent respective said distal ends said pair of vertical segments; and

said flexible elastic member imparting a compressive bias to said two vertical segments in their removable engagement with said horizontal segment.

10. The portable back rest apparatus of claim 2, additionally comprising:

said engagement of each said fin with an exterior surface of a respective said vertical segment, being a collar surrounding said exterior surface, said collar engaged with a first end of said fin;

each said collar being slidably adjustable in position upon a respective said exterior surface of a said vertical segment to adjust a position of said in closer or further from a respective distal end; and

each said collar having a releasable connector to fix said collar in a chosen position upon the respective vertical segment to which it engages.

11. The portable back rest apparatus of claim 3, additionally comprising:

said engagement of each said fin with an exterior surface of a respective said vertical segment, being a collar surrounding said exterior surface, said collar engaged with a first end of said fin;

each said collar being slidably adjustable in position upon a respective said exterior surface of a said vertical segment to adjust a position of said in closer or further from a respective distal end; and

each said collar having a releasable connector to fix said collar in a chosen position upon the respective vertical segment to which it engages.

12. The portable back rest apparatus of claim 5, additionally comprising:

said engagement of each said fin with an exterior surface of a respective said vertical segment, being a collar surrounding said exterior surface, said collar engaged with a first end of said fin;

each said collar being slidably adjustable in position upon a respective said exterior surface of a said vertical segment to adjust a position of said in closer or further from a respective distal end; and

each said collar having a releasable connector to fix said collar in a chosen position upon the respective vertical segment to which it engages.

13. The portable back rest apparatus of claim 6, additionally comprising:

said engagement of each said fin with an exterior surface of a respective said vertical segment, being a collar surrounding said exterior surface, said collar engaged with a first end of said fin;

each said collar being slidably adjustable in position upon a respective said exterior surface of a said vertical segment to adjust a position of said in closer or further from a respective distal end; and

each said collar having a releasable connector to fix said collar in a chosen position upon the respective vertical segment to which it engages.

14. The portable back rest apparatus of claim 8, additionally comprising:

said engagement of each said fin with an exterior surface of a respective said vertical segment, being a collar surrounding said exterior surface, said collar engaged with a first end of said fin;

each said collar being slidably adjustable in position upon a respective said exterior surface of a said vertical segment to adjust a position of said in closer or further from a respective distal end; and

each said collar having a releasable connector to fix said collar in a chosen position upon the respective vertical segment to which it engages.

15. The portable back rest apparatus of claim 9, additionally comprising:

said engagement of each said fin with an exterior surface of a respective said vertical segment, being a collar surrounding said exterior surface, said collar engaged with a first end of said fin;

each said collar being slidably adjustable in position upon a respective said exterior surface of a said vertical segment to adjust a position of said in closer or further from a respective distal end; and

each said collar having a releasable connector to fix said collar in a chosen position upon the respective vertical segment to which it engages.