Iso-truss structure
An iso-truss structure (10) includes at least two helical components (30, 32) and at least one reverse helical component (34) attached thereto with opposing angular orientations. Each helical and reverse helical component preferably includes at least four elongate, straight segments (22) rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about a common axis (14) forming a first square cross section. The structure may further include at least two rotated helical components (80, 92) and at least one rotated reverse helical component (98) which are rotated with respect to the helical and reverse helical components forming a second square cross section, rotated with respect to the first. The structure may be straight, curved, flexible, or form angles.
1. The Field of the Invention
The present invention relates generally to a three-dimensional structural member which is strong and light-weight. More particularly, the present invention relates to a structural member having a plurality of helical components wrapped about an axis, each having straight segments connected end-to-end in a helical configuration.
2. The Background Art
The pursuit of structurally efficient structures in the civil, mechanical, aerospace and sports arenas is an ongoing quest. An efficient truss structure is one that has a high strength to weight ratio and/or a high stiffness to weight ratio. An efficient truss structure can also be described as one that is relatively inexpensive, easy to fabricate and assemble, and does not waste material.
Trusses are typically stationary, fully constrained structures designed to support loads. They consist of straight members connected at joints at the end of each member. The members are two-force members with forces directed along the member. Two-force members can only produce axial forces such as tension and compression forces in the member. Trusses are often used in the construction of bridges and buildings. Trusses are designed to carry loads which act in the plane of the truss. Therefore, trusses are often treated, and analyzed, as two-dimensional structures. The simplest two-dimensional truss consists of three members joined at their ends to form a triangle. By consecutively adding two members to the simple structure and a new joint, larger structures may be obtained.
The simplest three-dimensional truss consists of six members joined at their ends to form a tetrahedron. By consecutively adding three members to the tetrahedron and a new joint, larger structures may be obtained. This three dimensional structure is known as a space truss.
Frames, as opposed to trusses, are also typically stationary, fully constrained structures, but have at least one multi-force member with a force that is not directed along the member. Machines are structures containing moving parts and are designed to transmit and modify forces. Machines, like frames, contain at least one multi-force member. A multi-force member can produce not only tension and compression forces, but shear and bending as well.
Traditional structural designs have been limited to one or two-dimensional analyses resisting a single load type. For example, I-beams are optimized to resist bending and tubes are optimized to resist torsion. Limiting the design analysis to two dimensions simplifies the design process but neglects combined loading. Three-dimensional analysis is difficult because of the difficulty in conceptualizing and calculating three-dimensional loads and structures. In reality, many structures must be able to resist multiple loadings. Computers are now being utilized to model more complex structures.
SUMMARY OF THE INVENTIONIt has been recognized that it would be advantageous to develop a structural member with enhanced performance characteristics, such as strength reduced weight, etc.
The invention provides a three-dimensional structure or structural member, including: 1) at least two, spaced apart, helical components, and 2) at least one reverse helical component attached to the two helical components. The helical and reverse helical components have a common longitudinal axis, but opposing angular orientations about the axis.
In addition, each helical and reverse helical component advantageously includes at least four elongate, straight segments rigidly connected end-to-end in a helical configuration forming a single, substantially complete rotation about the axis. Thus, the helical and reverse helical components form a first square-shaped cross section. In one aspect, the structure includes four helical components and four reverse helical components.
In addition, the iso-truss structure can include 1) rotated helical components, and 2) rotated reverse helical components, similar to, but rotated with respect to, the helical and reverse helical components above. Thus, the rotated helical and rotated reverse helical components form a second square-shaped cross section, rotated with respect to the first. In one aspect, the structure includes four rotated helical components and four rotated reverse helical components, for a total of sixteen helical components.
The various helical components intersect at external nodes and internal nodes. In one aspect, the components form eight internal and eight external nodes. Longitudinal or axial components may extend parallel to the axis and intersect the internal and/or external nodes. In one aspect, the structure includes eight external nodes. It has been found that such an eight node structure has unexpected structural or performance characteristics.
In accordance with one aspect of the present invention, the structure can further include an end plate attached at an end of the helical components to attach the helical components to another object. In one aspect, the helical components may be formed of continuous strands of fiber, which may be wound around the end plate. The end plate can include a perimeter with a plurality of indentations to receive the strands of fiber.
In accordance with another aspect of the present invention, the structure can further include a connector member attached to the helical components and segments to attach other objects to the helical components and segments. The connector member can include a triangular cross-sectional shape extending through triangular openings formed by the components.
In accordance with another aspect of the present invention, the helical and reverse helical components may form an angle therebetween greater than approximately 60 degrees. It has been found that such angles have unexpected structural or performance characteristics.
In accordance with another aspect of the present invention, the helical and reverse helical members can be axially and/or laterally flexible, but torsionally stiff. The structure may bend between a first, straight position in which the axes are substantially straight; and a second, arcuate position in which the axes are substantially arcuate. In addition, the structure may compress and/or expand longitudinally. In either case, the structure may store energy, and thus be utilized as a spring member.
In accordance with another aspect of the present invention, the structure may be arcuate, and the components may be formed about an arcuate axis. Thus, the arcuate structure may form more complex shapes than a singular, linear structure, and may be better suited for certain applications.
In accordance with another aspect of the present invention, the structure may taper. The segments of each helical component may sequentially reduce in length along the axes such that the structural member tapers. Thus, the tapering structure may form more complex shapes than a singular, linear structure, and may be better suited for certain applications.
In accordance with another aspect of the present invention, the iso-truss structure may be utilized to hold signs, utility lines, or lights. The iso-truss structure further may be utilized for bicycle frames, aircraft and marine structures, etc.
A method for forming an iso-truss structure in accordance with the present invention can include wrapping a fiber around a mandrel in order to create the two helical components and the reverse helical component. A matrix or resin can be added to the fiber and cured. The mandrel may be removed from the structure.
The mandrel may include a plurality of heads disposed thereon to receive and hold fiber. The mandrel may be a collapsible or dissolvable mandrel.
Additional features and advantages of the invention will be set forth in the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate by way of example, the features of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the exemplary embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications of the inventive features illustrated herein, and any additional applications of the principles of the invention as illustrated herein, which would occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the invention.
Improved Iso-Truss Structure
Some basic features of an iso-truss structure are described in U.S. Pat. No. 5,921,048, issued Jul. 13, 1999, which is herein incorporated by reference. As illustrated in
In one aspect, each helical component 20 advantageously includes at least four straight segments 22 which form a single, substantially complete rotation about the axis 14. Thus, when viewed along the axis 14, the four straight segments 22 form a square, or have a square cross-sectional shape, best seen in
In one aspect, the basic structure of the iso-truss structure 10 includes 1) at least two helical components 30 and 32, and 2) at least one reverse helical component 34, all wrapping around the axis 14. In another aspect, the basic structure 10 includes 1) four helical components 30, 32, 36 and 38, and 2) four reverse helical components 34, 40, 42 and 44. The helical components 30 and 32 wrap around the axis 14 in one direction, for example clockwise, while the reverse helical component 34 wraps around the axis 14 in the opposite direction, for example counterclockwise. The helical components 30 and 32, and segments 22 thereof, have a common angular orientation and a common axis 14. The reverse helical component 34, and segments thereof, have a similar helical configuration to the helical components 30 and 32, but an opposing angular orientation. This basic structure 10, when viewed from the end or axis 14 (
Referring to
Referring to
Referring to
Referring again to
Referring to
Referring to
Referring again to
As described above, the straight segments 22 of the helical components 30, 32, 36 and 38 have a common angular orientation, a common axis 14, and are spaced apart from each other at equal distances. Similarly, the segments of the reverse helical components 34, 40, 42 and 44 have a common angular orientation, a common axis 14, and are spaced apart from each other at equal distances. But the straight segments of the reverse helical components 34, 40, 42 and 44 have an opposing angular orientation to the angular orientation of the segments of the helical components 30, 32, 36 an 38. Again, this structure, when viewed from the end or axis 14, appears as an imaginary tubular member of square cross section, as shown in
The straight segments of the rotated helical components 80, 92, 94 and 96 have a common angular orientation, a common axis 14, and are spaced apart from each other at equal distances, like the helical components 30, 32, 36 and 38. The segments of the rotated reverse helical components 98, 110, 112 and 114 have a common angular orientation, a common axis 14, and are spaced apart from each other at equal distances, like the reverse helical components 34, 40, 42 and 44. But the straight segments of the rotated reverse helical components 98, 110, 112 and 114 have an opposing angular orientation to the angular orientation of the segments of the rotated helical components 80, 92, 94 and 96.
The rotated helical components 80, 92, 94 and 96 and the rotated reverse helical components 98, 110, 112 and 114 are rotated with respect to the helical components 30, 32, 36 and 38 and reverse helical components 34, 40, 42 and 44. In other words, this structure, when viewed from the end or axis 14, appears as an imaginary tubular member of square cross section, but is rotated with respect to the imaginary tubular member created by the helical and reverse helical components, as shown in
Two or more single elements 12 connect or intersect at joints 120 (
A bay 128 (
An internal angle 130 (
The repeating pattern may be described as a number of triangles or tetrahedrons. The triangles and tetrahedrons are of various sizes with smaller triangles and tetrahedrons being interspersed among larger triangles and tetrahedrons.
The structure 10 may be conceptualized as two, imaginary tubular members of square cross section overlaid to form a single imaginary tube with a cross section like an eight-pointed star, as shown in
In addition, when viewed from the end or the axis 14, it is possible to define eight planes parallel with the axis 14. The planes extend between specific external nodes 122 in an eight-pointed star configuration. The planes are oriented about the axis 14 at 45 degree intervals.
Furthermore, within a bay 128, a ring of triangular grids is formed which are believed to have strong structural properties. This ring of triangular grids circle the interior of the structure 10 in the center of the bay, as shown in
The helical components 30, 32, 36 and 38 intersect with reverse helical components 34, 40, 42 and 44 at external nodes 122. Similarly, rotated helical components 80, 92, 94 and 96 intersect with rotated reverse helical components 98, 110, 112 and 114 at external nodes 122.
The helical components 30, 32, 46 and 38 intersect with rotated reverse helical components 98, 110, 112 and 114 at internal nodes 124. Similarly, the rotated helical components 34, 40, 42 and 44 intersect with reverse helical components 80, 92, 94 and 96 at internal nodes 124.
The helical components 30, 32, 36 and 38 and rotated helical components 80, 92, 94 and 96 do not intersect. Likewise, the reverse helical components 36, 40, 42 and 44 and rotated reverse helical components 98, 110, 112 and 114 do not intersect.
In addition to the plurality of helical members, the structure 10 also may have eight internal axial members 132 (
The external and internal nodes 122 and 124 may form rigid connections, or the components may be rigidly connected together. In addition, the axial members 132 may be rigidly coupled to the components at the internal nodes 124. The components can be made from a composite material. The helical configuration of the structure 10 makes it particularly well suited for composite construction. The components are coupled together as the fibers of the various components overlap each other. The fibers may be wound in a helical pattern about a mandrel following the helical configuration of the member, as described in greater detail below. This provides great strength because the segments of a component are formed by continuous strands of fiber. The elements or components may be a fiber, such as fiber glass, carbon, boron, basalt or Kevlar (aramid), in a matrix, such as a thermoset (epoxy, vinyl ester, etc.), or even a thermoplastic (polyester, polypropylene, PVC, etc.). In addition, an additive may be included in the resin or matrix, such as UV protectors, or chemical repellents.
Alternatively, the structure 10 may be constructed of any suitable material, such as wood, metal, plastic, or ceramic and the like. The elements of the member may consist of prefabricated pieces that are joined together with connecters at the nodes 122. The connector has recesses formed to receive the elements. The recesses are oriented to obtain the desired geometry of member 10.
It is believed that the multiple symmetric and highly redundant nature of the structure 10 provides an attractive, efficient, and damage tolerant structure, with the three-dimensional configuration of the structure 10 providing substantial resistance to local buckling. The structure 10 incorporates stable geometric forms with members that spiral in a piecewise linear fashion in opposing directions around a central cavity. The helical and longitudinal members are repeatedly interwoven, yielding a highly redundant and stable configuration.
In addition, the structure 10 takes advantage of the mechanical properties of continuous fiber in the primary load paths. The load is transferred through beam segments to the intersections, where it disperses through other beam segments. Each member carries primarily axial loads, taking full advantage of the inherent strength and stiffness of continuous fiber-reinforced composites. The helical members primarily carry the torsion and transverse shear loads and stabilize the longitudinal members against buckling when loaded in flexure or axial compression, while the longitudinal members primarily carry the axial and flexural loads and stabilize the helical members against buckling when loaded in torsion or transverse shear. Multiple interweaving of the longitudinal and helical members at the joints or nodes provides a strong interlocking mechanism to enable this type of interdependent three-dimensional stabilization.
Furthermore, the highly redundant nature of the structure 10 makes it very damage tolerant. Removal of a single member results in only fractional degradation of the overall structure. In fact, removal of a complete node reduces the effective properties by approximately 1/N, where N represents the number of nodes in a single cross-section. This damage tolerance capability provides a significant performance advantage over traditional shell structures.
Failure of composite iso-grid structures typically displays a more ductile overall behavior than is generally observed in advanced composite structures. Although the initial response is still linear elastic to the ultimate load, the subsequent behavior after damage initiation is generally nonlinear. In compression, this nonlinearity generally includes a roughly 1/N drop in load each time the members through one of the nodes fail. In flexure, the failure is less ductile, since the load is concentrated in fewer members.
Failure initiation under one load type causes only minimal reduction in strength when loaded in another direction, although the stiffness may be more adversely affected. Furthermore, failure of the principal load carrying members has little or no effect on the ability of the secondary load carrying members to resist simple loading. Failure of one bay in compression has little effect on the torsion capacity of the structure, although the corresponding toughness is reduced. In other words, local failure of the primary members has little effect on the capacity of the secondary members.
From the basic configuration of the structure 10 described above, several alternative configurations are possible with the addition of additional members. Referring to
The perimeter members 144 may be located around the perimeter of the structure 10 between nodes 122 on a diagonal with respect to the longitudinal axis 14. These diagonal perimeter members may be formed by segments of additional helical components wrapped around the perimeter of the plurality of helical components 20. The diagonal perimeter members may extend between adjacent nodes 122, or extend to alternating nodes 122. Such perimeter members may form another iso-truss structure about the first, or a double iso-truss structure. Such a configuration creates a relatively smooth outer surface or supporting structure that simplifies application of an outer skin for cosmetic of structural purposes. The double iso-truss structure also provides enhanced stiffness per unit weight.
As stated above, the improved iso-truss structure of the present invention preferably includes sixteen helical components which each include four segments forming a full rotation about the axis 14 to form square cross sections, and may be referred to as an eight node structure. A side-by-side comparison of the eight and six node configurations is shown in
External axial members 140 and perimeter members 144 have been added to the structures shown in
The eight node configuration results in the structure 10 having parallel sides, which makes the structure more square and better suited for applications which prefer square geometries. For example, the eight node configuration fits better in a box, due to its parallel and perpendicular sides, permitting greater suitability for numerous internal stiffening applications where the dimensions of the structure are constrained.
In addition, the increased number of nodes increases the angle between adjacent segments or members of each helical component. It will be appreciated that with a six node configuration, each helical component would have three segments or members forming a complete rotation, or a triangle, with a relatively sharp angle between adjacent segments or members. Such sharp angles act as points of stress concentration, and may be subject to failure. With an eight node configuration, however, each helical component has four segments or members forming a substantially complete rotation, or a square, with relatively wider angles, which may have reduced stress and failure. Furthermore, the nodes may be more rounded to further reduce stress concentration. The eight node configuration, with wider angles, facilitates rounded nodes, and thus reduces stress concentrations.
In addition, the eight node configuration has more unobstructed internal space (free volume) as a percentage of the total cross-sectional area, permitting easier fabrication and yielding more internal volume for non-structural purposes than the six node configuration.
Performance Characteristics
Referring to
Referring to
Angular Configuration
Referring again to
From the figures, it can be seen that the bending and axial (tension) properties of the structure improve as the angle 130 increases. Other properties, however, such as buckling and torsion appear to be reduced as the angle increases. One problem with tubular composite structures is their poor bending properties, or they bend too easily. The structure of the present invention, however, and the increased angle, demonstrates improved, or stiffer, bending properties.
End Connections
Referring to
Referring to
Referring to
Other grooves or indentations 131 may be formed in the plate 126 or fingers 130 and located and oriented to receive the various segments of the structure therein, such that the fingers 130 “snap” around the various segments to hold the structure to the plate 126. Holes 132 can be formed through the fingers 130, the groove 127, and into the plate 126 to receive bolts or screws to further secure the structure in the groove 127. The holes 132 are located such that the bolts or screws pass through the structure around various segments thereof. Such a configuration has the advantage that the structure can be snapped into the plate.
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
The ends 172 and 173 are configured to engage and attach to the structures 10 and 171, respectively. Each end 172 and 173 preferably is formed into a hook-like configuration for securing to the segments of the structures. The ends 172 and 173 can include an angled, U-shaped member 176 for engaging the segments of the structures. Thus, members 176 extend from the ends inwardly towards the structures, and then angle longitudinally or axially, to form a hook. In addition, the U-shaped members 176 may extend along either side of an axial member. Thus, the U-shaped members 176 can be hooked to the structures, and the first and second portions of the axial member 174 drawn together by rotating the attachment member 175, in order to draw the first and second structures 10 and 171 together in a secure or attached relationship.
Referring to
Intermediate Connections
In addition to connecting the iso-truss structure 10 at its ends, it may be necessary or desirable to attach other objects at an intermediate point of the iso-truss structure. Referring to
Referring to
As stated above, various other objects may be attached to the structure 10, or the attachment members 180. Referring to
Referring to
Brackets 193 can be configured to surround the ends of the pair of attachment members 180. Various objects may be attached to the brackets 193, such as eyes for suspending other objects, as shown.
Referring to
Referring to
The attachment members described above preferably are triangular to match the openings extending through the structure 10. Referring to
Referring to
Referring to
Referring to
Many of the attachment members described above have been described as extending through the structure 10. Referring to
In addition, the attachment member may have other cross sectional shapes and be configured to extend through other cross sectional openings in the structure. For example, the attachment member may have a quadrilateral cross sectional shape and extend through a quadrilateral opening in the structure.
One or more nodes may be removed or left out to facilitate attachment of an object to the structure. For example, leaving out one node presents a flatter side. In addition, opposite nodes can be left out for flatter, opposite sides, for an attachment through the structure.
Tapering Iso-Truss Structure
Referring to
Referring to
Flexible or Bendable Iso-Truss Structure
Referring to
The lack of the longitudinal components allows the structure 240 to bend or flex in a lateral direction. It has been discovered, however, that although the structure 240 is capable of bending in a lateral direction, the structure 240 continues to maintain its torsional stiffness, or resist rotation about the longitudinal axis 14.
In addition, a similar structure also can compress and/or expand axially or longitudinally. Thus, the structure may expand and/or compress, preferably storing energy, so that the structure can function as a spring member.
Angled Iso-Truss Structures
Referring to
The structure 250 may have exterior axial members 256 attached to the external nodes 122. Alternatively, a structure 258 may be angled, but without exterior axial members, as shown in
Curved Iso-Truss Structures
Referring to
Referring to
The curved or circular configurations of the iso-truss structure are believed to impart the same structural advantages of the straight iso-truss structures to the curved and circular structures.
Referring to
The structure may have a broad curved section as shown in
Referring to
Braided Pre-Form
As stated above, many of the above-described structures may be formed by resin impregnated fibers, to form rigid structures. Many of the above-described structures may also be provided in a braided pre-form configuration. The structures may be formed by winding strands of fiber together. In addition, additional strands of fiber may be wrapped around segments to hold the fibers together. The strands of fiber, however, without their resin, remain flexible, and may be collapsed and expanded as desired. Thus, such a braided pre-form may be collapsed or substantially compacted into a small area for transportation, etc. The braided pre-form may then be expanded and impregnated with resin to form the desired structure.
Referring to
In addition, the fibers or segments can be twisted to compact the fibers. Furthermore, the segments, or fibers thereof, can be wrapped, such as in a spiral, with other fibers for compaction.
Integral Connectors
Referring to
The connectors 350 can have a circular cross-sectional shape, similar to cylindrical composite tubes, and be received within a circular opening in a receiving connector, as described below. The connector 350 may be threaded 353, or have external threads, as shown in
Various shaped members may be provided for connecting structures. For example, union 360 or 361 can have opposing openings for receiving connectors 352 or 356 from two structures, to couple the structures together in an end-to-end configuration, as shown in
Other Attachments
Other attachments also are possible. Referring to
Signs
Referring to
Referring to
Referring to
Utility Poles
Referring to
Referring to
Referring to
Bicycle Frames
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Method of Manufacturing
As discussed above, the iso-truss structures preferably are formed by fibers impregnated with resin. In addition, the iso-truss structures or helical components preferably are formed by continuous strands of fiber wrapping around the longitudinal axis and along the length of the iso-truss structure. Such a composite iso-truss structure may be formed using a mandrel. It will be appreciated that the complicated geometry of the iso-truss structure presents a manufacturing challenge.
Referring to
The mandrel 700 may include an elongated core or body 704, and a plurality of heads 706 disposed thereon. The core or body 704 preferably has a reduced or smaller diameter with respect to the iso-truss structure, such that the core or body 704 may reside within the iso-truss structure without interfering with any of the segments or helical components. The heads 706 preferably are spaced apart from the core or body 704. The heads 706 extend radially from the core or body 704 and towards the exterior nodes 122 of the iso-truss structure. The heads 706 are configured to receive the strands of fiber 702 as they are wrapped about the mandrel 700. Therefore, for an eight node iso-truss structure, eight heads 706 extend radially around the circumference of the core or body 704. In addition, a number of heads 706 extend along the length of the core or body 704 in accordance with the length of the desired iso-truss structure.
Referring to
In addition, the indentations 710 preferably include one or more sets of shallow indentations 718 and 720. One set of shallow indentations 718 may be utilized to form longitudinal components of the iso-truss structure, while the other shallow indentations 720 may be utilized to form radial or lateral components of the iso-truss structure.
In order to form an iso-truss structure as described above, strands of fiber can be wrapped around the mandrel in order to create the helical components and segments thereof. The strands of fiber 702 may be wrapped about the mandrel as described above with respect to the helical components, placing the strands of fiber in the indentations of the head. In addition, the strands of fiber may be impregnated with resin as they are wrapped around the mandrel 700. Alternatively, the strands of fiber may be wrapped around the mandrel without impregnating them with resin as discussed above to form a braided pre-form. The resin is then cured and the mandrel may then be removed from the iso-truss structure. Alternatively, the iso-truss structure may be integrally formed with a mandrel and the mandrel may remain therein.
It will be appreciated that the complex geometry of the iso-truss structure, and the extension of the heads from the mandrel, create a challenge in removing the mandrel from the iso-truss structure. Various types of mandrels may be utilized in order to form the iso-truss structure. For example, a dissolvable mandrel may be formed by salt, or sand with a binder, which is dissolved to remove the mandrel from the iso-truss structure. As another example, eutectic metals may be used which can be melted away from the iso-truss structure. As another example, a balloon mandrel may be utilized which includes a sand-filled bladder which is packed with sand and vacuum sealed to form the mandrel, and then the vacuum is released and the bladder emptied of sand to remove the mandrel from the iso-truss structure.
In addition, the iso-truss structure may be formed by wet or dry wrapping fibers around an internal mold, and then enclosed by an external mold, similar to injection molding. Such a molding process can provide good consolidation, good shape definition, and good surface finish.
Referring to
After the iso-truss structure has been formed on the mandrel 720, the core 730 may be removed from the tubular body 722 by sliding the core 730 outwardly from the tubular body 722. Removal of the core 730 allows the insert 732 to be removed from the tubular body 722, and the pins 728 to move inwardly into the tubular body 722. Thus, the pins may be removed and the tubular body 722 removed from the iso-truss structure. In addition, the heads 724 may be removed.
Referring again to
The mandrel 740 may be assembled by inserting the pins 728 into apertures in the core or tube 722. Collars also may be disposed at the ends of the tube 722 to form the integral connectors, as described above. The heads 724 are disposed on the pins 728. The fibers are wrapped about the heads 724 to form the helical members and axial members. In addition, the fibers are wrapped around the collars to form the integral connectors. The mandrel is removed to leave the structure.
Additional Applications
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
The iso-truss structures can be used in buildings and construction. Referring to
The iso-truss structures can be used in vessels, boats and ships. Referring to
Referring to
Referring to
The iso-truss structures also can be used to transmit torque or rotational movement. Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
The configurations shown in
Referring to
Referring to
Referring to
The iso-truss structures described above can be utilized in other applications as well. For example, the iso-truss structure can be included in the mast of a boat with a sail coupled thereto. The iso-truss structure can be included in a flag post with a flag coupled thereto. The iso-truss structure can be included in a fence post with fence members attached thereto.
In addition, a skin, covering or wrap may be disposed around the structure. Such a skin may strengthen the structure, prevent climbing, and/or be aesthetic.
The iso-truss structures described above also may be utilized to reinforce concrete. For example, concrete may be poured or otherwise formed about the structures, and may fill the interior of the structures.
The iso-truss structures have been described above with particular reference to an eight node structure in which the helical components have four straight segments forming a single, complete rotation about the axis. It is of course understood that other configuration can be useful, including for example, structure with five, six, seven, nine, twelve, etc. nodes.
It is to be understood that the above-described arrangements are only illustrative of the application of the principles of the present invention. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the present invention and the appended claims are intended to cover such modifications and arrangements. Thus, while the present invention has been shown in the drawings and fully described above with particularity and detail in connection with what is presently deemed to be the most practical and preferred embodiment(s) of the invention, it will be apparent to those of ordinary skill in the art that numerous modifications, including, but not limited to, variations in size, materials, shape, form, function and manner of operation, assembly and use may be made, without departing from the principles and concepts of the invention as set forth in the claims.
Claims
1. A structural member, comprising:
- a) at least two, spaced apart, helical components each having: 1) a common longitudinal axis, 2) a common angular orientation about the axis, and 3) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis; and
- b) at least one reverse helical component, attached to the at least two helical components, having: 1) a common longitudinal axis with the at least two helical components, 2) an opposing angular orientation with respect to the two helical components, and 3) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis.
2. A structural member in accordance with claim 1, wherein all of the helical components have continuous strands of fiber; and wherein the helical components are attached to one another at intersecting locations by over-lapping the fibers of the helical components.
3. A structural member in accordance with claim 1, wherein the helical components define a hollow interior substantially void of material.
4. A structural member in accordance with claim 1, wherein the helical components define openings there between.
5. A structural member in accordance with claim 1, wherein helical components define an imaginary tubular member of square cross section.
6. A structural member in accordance with claim 1, further comprising:
- a) at least two, spaced apart, rotated helical components, attached to and rotated with respect to the at least two helical components and at least one reverse helical component, each having: 1) a common rotated longitudinal axis, 2) a common angular orientation about the rotated longitudinal axis, and 3) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the rotated axis; and
- b) at least one rotated reverse helical component, attached to and rotated with respect to the at least two helical components and at least one reverse helical component, having: 1) a common rotated longitudinal axis with the at least two rotated helical components, 2) an opposing angular orientation with respect to the two rotated helical components, and 3) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis.
7. A structural member in accordance with claim 6, wherein the longitudinal axis and the rotated longitudinal axis are concentric, and the segments of the helical components form an imaginary tubular member having a cross section of an eight-pointed star.
8. A structural member in accordance with claim 6, wherein the longitudinal axis and the rotated longitudinal axis are concentric, and the segments form an imaginary tubular member having a cross section of two squares having a common longitudinal axis, but with one square rotated with respect to the other.
9. A structural member in accordance with claim 1, further comprising:
- an end plate, attached at an end of the helical components, to attach the helical components to another object.
10. A structural member in accordance with claim 9, wherein the helical components have continuous strands of fiber; and wherein the end plate is attached by winding the continuous strands of fiber around the end plate.
11. A structural member in accordance with claim 9, wherein the end plate includes a perimeter, a plurality of indentations formed about the perimeter to receive strands of fiber, and a plurality of holes to attach the end plate to another object.
12. A structural member in accordance with claim 1,
- wherein the helical components and segments form a repeating pattern of triangles and tetrahedrons; and further comprising:
- a connector, attached to the helical components and segments, to attach other objects to the helical components and segments, the connector being elongated and having a substantially triangular, cross sectional shape, the connector extending through at least two of the triangles formed by the helical components and segments.
13. A structural member in accordance with claim 1, wherein the axes are vertically oriented, a lower end is attached to a support surface, and an upper end is located above the lower end; and further including another object attached to the upper end selected from the group consisting of: a sign placard with indicia; a horizontal utility member configured to hold utility lines; a light source.
14. A structural member, comprising:
- a) at least two, spaced apart, helical components each having: 1) a common longitudinal axis, 2) a common angular orientation about the axis, and 3) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis;
- b) at least one reverse helical component, attached to the at least two helical components, having: 1) a common longitudinal axis with the at least two helical components, 2) an opposing angular orientation with respect to the two helical components, and 3) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis;
- c) at least two, spaced apart, rotated helical components, attached to and rotated with respect to the at least two helical components and at least one reverse helical component, each having: 1) a common rotated longitudinal axis, 2) a common angular orientation about the rotated longitudinal axis, and 3) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the rotated axis; and
- d) at least one rotated reverse helical component, attached to and rotated with respect to the at least two helical components and at least one reverse helical component, having: 1) a common rotated longitudinal axis with the at least two rotated helical components, 2) an opposing angular orientation with respect to the two rotated helical components, and 3) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis.
15. A structural member in accordance with claim 14, wherein the longitudinal axis and the rotated longitudinal axis are concentric, and the segments of the helical components form an imaginary tubular member having a cross section of an eight-pointed star.
16. A structural member in accordance with claim 14, wherein the longitudinal axis and the rotated longitudinal axis are concentric, and the segments form an imaginary tubular member having a cross section of two squares having a common longitudinal axis, but with one square rotated with respect to the other.
17. A structural member, comprising:
- a) at least two, spaced apart, helical components each having: 1) a common longitudinal axis, 2) a common angular orientation about the axis, and 3) at least three elongate, straight segments rigidly connected end to end in a helical configuration;
- b) at least one reverse helical component, attached to the at least two helical components, having: 1) a common longitudinal axis with the at least two helical components, 2) an opposing angular orientation with respect to the two helical components, and 3) at least three elongate, straight segments rigidly connected end to end in a helical configuration; and
- c) the at least one reverse helical component forming an angle with respect to the at least two helical components greater than 60 degrees.
18. A structural member in accordance with claim 17, wherein the at least one reverse helical component forms an angle with respect to the at least two helical components greater than approximately 75 degrees.
19. A structural member in accordance with claim 17, wherein each helical component includes at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis.
20. A flexible structural member, comprising:
- a) at least two, spaced apart, helical components each having: 1) a common longitudinal axis, 2) a common angular orientation about the axis, and 3) at least three elongate, straight segments rigidly connected end to end in a helical configuration;
- b) at least one reverse helical component, attached to the at least two helical components, having: 1) a common longitudinal axis with the at least two helical components, 2) an opposing angular orientation with respect to the two helical components, and 3) at least three elongate, straight segments connected end to end in a helical configuration; and
- c) the helical members being laterally flexible, and are bendable between: 1) a first, straight position in which the axes are substantially straight; and 2) a second, arcuate position in which the axes are substantially arcuate.
21. A structural member in accordance with claim 20, wherein the helical members store energy in the second, arcuate position.
22. A structural member in accordance with claim 20, wherein the helical members are rotationally rigid about the longitudinal axes.
23. An arcuate structural member, comprising:
- a) at least two, spaced apart, helical components each having: 1) a common arcuate axis, 2) a common angular orientation about the axis, and 3) at least three elongate, straight segments rigidly connected end to end in a helical configuration; and
- b) at least one reverse helical component, attached to the at least two helical components, having: 1) a common arcuate axis with the at least two helical components, 2) an opposing angular orientation with respect to the two helical components, and 3) at least three elongate, straight segments rigidly connected end to end in a helical configuration.
24. A structural member in accordance with claim 23, wherein the arcuate axes are circular.
25. A structural member in accordance with claim 23, wherein each helical component includes at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis.
26. A structural member in accordance with claim 23, wherein the arcuate axes include a first curvature, and a different second curvature.
27. A tapering structural member, comprising:
- a) at least two, spaced apart, helical components each having: 1) a common longitudinal axis, 2) a common angular orientation about the axis, and 3) at least three elongate, straight segments rigidly connected end to end in a helical configuration; and
- b) at least one reverse helical component, attached to the at least two helical components, having: 1) a common longitudinal axis with the at least two helical components, 2) an opposing angular orientation with respect to the two helical components, and 3) at least three elongate, straight segments rigidly connected end to end in a helical configuration; and
- c) the segments of each helical component sequentially reducing in length along the axes such that the structural member tapers.
28. A structural member in accordance with claim 27, wherein each helical component includes at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis.
29. A preform member, comprising:
- a) at least two, spaced apart, helical components each having: at least three segments connected end to end in a helical configuration; and
- b) at least one reverse helical component, attached to the at least two helical components, having: at least three segments connected end to end in a helical configuration; and
- c) the helical components including fiber and being flexible and collapsible until impregnated with a resin matrix.
30. A preform member in accordance with claim 29, wherein the helical components include a plurality of strands of fiber bound together.
31. A bicycle frame, comprising:
- a) a handlebar location configured to attach to a handlebar and front fork;
- b) a seat location configured to attach to a seat;
- c) a peddle location configured to be attached to a peddle assembly;
- d) a rear wheel location configured to be attached to a rear wheel;
- e) a plurality of members, each extending to and between at least one of the handlebar, seat, peddle, and rear wheel locations; and
- f) at least one of the members including: 1) at least two, spaced apart, helical components each having: i) a common longitudinal axis, and ii) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis; and 2) at least one reverse helical component, attached to the at least two helical components, having: i) a common longitudinal axis with the at least two helical components, and ii) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis in an opposing angular orientation.
32. A bicycle frame in accordance with claim 31, wherein each helical component includes at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis.
33. A method for forming a structural member, comprising the steps of:
- a) providing a mandrel;
- b) wrapping a fiber around the mandrel in order to create at least two helical components, each component having at least four elongated, straight segments, the at least two helical components having a common longitudinal axis, a common angular orientation about the axis, and forming a single, substantially complete rotation about the axis;
- c) wrapping a fiber around the mandrel in order to create at least one reverse helical component having at least four elongate, straight segments having a common longitudinal axis with the at least two helical components, but in an opposing angular orientation, and forming a single, substantially complete rotation about the axis;
- d) adding a matrix to the fiber; and
- e) curing the matrix.
34. A method in accordance with claim 33, wherein the step of providing a mandrel further includes:
- providing a mandrel having an elongated core, and a plurality of heads disposed longitudinally and radially about the core, each head configured to receive and hold fiber for at least two, opposing helical components, and including four angled indentations, two angled indentations for each helical component.
35. A method in accordance with claim 33, further comprising the step of:
- wrapping a fiber along a length of the mandrel in order to create at least one longitudinal component parallel with the longitudinal axes; and wherein the step of providing a mandrel further includes:
- providing a mandrel having an elongated core, and a plurality of heads disposed longitudinally and radially about the core, each head configured to receive and hold fiber for at least two, opposing helical components and at least one longitudinal component, and including at least six indentations, including two angled indentations for each helical component and two indentations for the longitudinal component.
36. A method in accordance with claim 33, wherein the step of providing a mandrel further includes providing a collapsible mandrel having:
- a) an elongated, hollow tube including a plurality of holes,
- b) an elongated core, removably disposed within the tube,
- c) a plurality of inserts, removably disposed between the core and the tube, having a plurality of holes,
- d) a plurality of pins, removably disposed in the holes of the tube and inserts, and
- e) a plurality of heads disposed on the pins; and further including the steps of:
- a) removing the core from the tube after curing;
- b) removing the inserts from the core;
- c) displacing the pins through the holes into the tube;
- d) removing the tube; and
- e) removing the heads.
37. A utility pole, comprising:
- a) an elongated member, vertically oriented, having a longitudinal axis and upper and lower ends, and being formed of: 1) at least two, spaced apart, helical components each having: i) a common angular orientation about the longitudinal axis, and ii) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis; and 2) at least one reverse helical component, attached to the at least two helical components, having: i) an opposing angular orientation with respect to the two helical components, and ii) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis;
- b) an end plate, attached to the lower end of the elongated member, configured to attach the lower end of the elongated member to a support surface; and
- c) an arm, attached to the elongated member near the upper end and extending generally horizontally, configured to hold a utility line.
38. A utility pole in accordance with claim 37, wherein the elongated member further includes:
- a) at least two, spaced apart, rotated helical components, attached to and rotated with respect to the at least two helical components and at least one reverse helical component, each having: 1) a common rotated longitudinal axis, 2) a common angular orientation about the rotated longitudinal axis, and 3) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the rotated axis; and
- b) at least one rotated reverse helical component, attached to and rotated with respect to the at least two helical components and at least one reverse helical component, having: 1) a common rotated longitudinal axis with the at least two rotated helical components, 2) an opposing angular orientation with respect to the two rotated helical components, and 3) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis.
39. A utility pole in accordance with claim 37, wherein the segments of each helical component sequentially reduce in length along the axes such that the structural member tapers.
40. A sign post, comprising:
- a) an elongated member, vertically oriented, having a longitudinal axis and upper and lower ends, and being formed of: 1) at least two, spaced apart, helical components each having: i) a common angular orientation about the longitudinal axis, and ii) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis; and 2) at least one reverse helical component, attached to the at least two helical components, having: i) an opposing angular orientation with respect to the two helical components, and ii) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis;
- b) an end plate, attached to the lower end of the elongated member, configured to attach the lower end of the elongated member to a support surface; and
- c) a sign, coupled to the elongated member, including indicia.
41. A sign post in accordance with claim 40, wherein the elongated member further includes:
- a) at least two, spaced apart, rotated helical components, attached to and rotated with respect to the at least two helical components and at least one reverse helical component, each having: 1) a common rotated longitudinal axis, 2) a common angular orientation about the rotated longitudinal axis, and 3) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the rotated axis; and
- b) at least one rotated reverse helical component, attached to and rotated with respect to the at least two helical components and at least one reverse helical component, having: 1) a common rotated longitudinal axis with the at least two rotated helical components, 2) an opposing angular orientation with respect to the two rotated helical components, and 3) at least four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis.
42. A sign post in accordance with claim 40, further comprising:
- a) an arcuate member having a first end attached to the upper end of the elongated member, and also including: 1) at least two, spaced apart, helical components each having: i) a common arcuate axis, ii) a common angular orientation about the axis, and iii) at least three elongate, straight segments rigidly connected end to end in a helical configuration; and 2) at least one reverse helical component, attached to the at least two helical components, having: i) a common arcuate axis with the at least two helical components, ii) an opposing angular orientation with respect to the two helical components, and iii) at least three elongate, straight segments rigidly connected end to end in a helical configuration; and
- b) the sign is coupled to the arcuate member.
43. A structural member, comprising:
- a) at least two, spaced apart, helical components each having: 1) a common longitudinal axis, 2) a common angular orientation about the axis, and 3) four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis; and
- b) at least one reverse helical component, attached to the at least two helical components, having: 1) a common longitudinal axis with the at least two helical components, 2) an opposing angular orientation with respect to the two helical components, and 3) four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis.
44. A structural member in accordance with claim 43, further comprising:
- a) at least two, spaced apart, rotated helical components, attached to and rotated with respect to the at least two helical components and at least one reverse helical component, each having: 1) a common rotated longitudinal axis, 2) a common angular orientation about the rotated longitudinal axis, and 3) four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the rotated axis; and
- b) at least one rotated reverse helical component, attached to and rotated with respect to the at least two helical components and at least one reverse helical component, having: 1) a common rotated longitudinal axis with the at least two rotated helical components, 2) an opposing angular orientation with respect to the two rotated helical components, and 3) four elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis.
45. A structural member, comprising:
- a) at least two, spaced apart, helical components each having: 1) a common longitudinal axis, 2) a common angular orientation about the axis, and 3) five elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis; and
- b) at least one reverse helical component, attached to the at least two helical components, having: 1) a common longitudinal axis with the at least two helical components, 2) an opposing angular orientation with respect to the two helical components, and 3) five elongate, straight segments rigidly connected end to end in a helical configuration forming a single, substantially complete rotation about the axis.
Type: Application
Filed: Jul 27, 2001
Publication Date: Jun 2, 2005
Inventors: David Jensen (Mapleton, UT), Larry Francom (Helper, UT)
Application Number: 10/343,133
