Flexible space frame, components thereof and method of construction

Abstract

A system of cross-shaped units and nodes used to construct strong, lightweight, inexpensive space frames with alternately rigid and flexible components, in which each cross-shaped unit which fits together with five like units to form a spherical node which can be connected to other nodes to form frames for the production of structures including toys, playground structures, lattices, pergolas, statues, roofs, furniture, fixtures, mattresses, kites, lamps, artistic structures and fixtures, floating platforms, flexible joints for machines or robots, buildings, bridges and space stations.

Claims

1. (canceled)

2. (canceled)

3. (canceled)

4. (canceled)

5. (canceled)

6. (canceled)

7. A space frame comprising a plurality of frame units wherein each such unit is connected by a snap fit connection between respective connector piece assemblies of each of the units, such frame comprising opposite unit designs, wherein each such unit consists of a spherical unit comprised of six cross-shaped members, each such cross-shaped member comprising a cross-piece with four equidistant arms, each extending outward towards a distal end, each end comprising an integrated connector piece designed to interlock with other connector pieces, each such connector piece comprising a distal connecting pin with a ledge and an angled edge for locking, a distal connecting hole, a short side alignment pin, a short side alignment hole, a tall side alignment pin, a tall side alignment hole a channel and a semicircular protrusion, wherein each pair of connector pieces interlock using the side alignment pins and side alignment holes to form a connector piece assembly with two distal connecting pins and two distal connecting hole, wherein each connector piece is interlocked with another connector piece to form twelve total connector piece assemblies and six convex surfaces, wherein each pair of connector pieces interlocks using the distal connecting pins and distal connecting holes to form a connector piece assembly with two tall side pins, two short side pins, two tall side holes and two short side holes; wherein each connection of multiple spherical units results in forming a reverse unit wherein each cross-shaped member is inverted, yielding six concave surfaces, wherein each pair of connector pieces interlocks by inserting the side alignment pins into the corresponding side alignment holes to form twelve connector piece assemblies, each connector piece assembly locked with two overlocking blocks and comprising two distal connecting pins and two distal connecting holes.

8. (canceled)

9. The space frame of claim 7, comprising a plurality of octahedral units, with a spherical unit of claim 7 arranged inside of each octahedral unit.

10. (canceled)

11. (canceled)

12. (canceled)

13. (canceled)

14. (canceled)

15. The space frame of claim 7, wherein all frame units are armillary spheres interlocked in a face-centered cubic arrangement.

16. The space frame of claim 7, wherein a flexible first frame area consisting of a plurality of armillary spheres interlocked in a face-centered cubic arrangement, further comprising a rigid second frame area comprising both tetrahedral and octahedral units, with a spherical unit of claim 7 arranged inside or attached to at least one octahedral unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is a line drawing evidencing a cross-shaped member with connector pieces at each end. The flattened portions make up the struts of the final structure. The ends of the member are used to connect to another cross-shaped members or other fittings designed for a variety of uses. This cross-shaped member can be manufactured by a plastic injection mold or by 3D printing.

[0027] FIG. 2 is a line drawing evidencing an alternate formation the cross-shaped member of FIG. 1 in which the member is flipped over and bent.

[0028] FIG. 3 is a line drawing evidencing the interlocking design of the connector pieces of two cross-shaped members.

[0029] FIG. 4 is a line drawing evidencing two aligned connector pieces further comprising two optional single barrel crimping sleeves 61 clamping on a connector rod.

[0030] FIG. 5A is a line drawing evidencing six cross-shaped members locked together to form a spherical unit.

[0031] FIG. 5B is a line drawing evidencing multiple cross-shaped members locked together to form an alternate reverse unit, also comprised of six cross-shaped members.

[0032] FIG. 6 is a line drawing evidencing the interlocking connector pieces of two spherical units.

[0033] FIG. 7 is a line drawing evidencing two spherical units jointed at one connector piece assembly.

[0034] FIG. 8 is a line drawing evidencing a frame comprised of multiple interlocked spherical units, such units in an alternate embodiment whereby one cross-shaped member of several units are is missing to form an open top, with the open top of each such unit facing the same direction.

[0035] FIG. 9 is a line drawing evidencing a single cross-shaped member with a helical curvature and a c-channel cut axially along each of the four arms.

[0036] FIG. 10 is a line drawing evidencing an exploded view of a helically curved c-channel node. Each of the three parts are identical triplets and each have the necessary integral parts to align and snap into two additional like units.

[0037] FIG. 11 is a line drawing evidencing the fully-assembled helical curved c-channel node, comprising six c-channels that surround and circumvent a central point.

[0038] FIG. 12 is a line drawing evidencing six fully-assembled helical curved c-channel nodes with rods emanating from each node to tie into other like nodes.

[0039] FIG. 13 is a line drawing evidencing one potential frame assembly embodiment utilizing each of the spherical, reverse and helical curved c-channel types of units in concert.

[0040] FIG. 14 is a line drawing evidencing the frame of FIG. 13, wherein the frame has one piezo-electric crystal inserted into the frame and another being introduced into the matrix.

[0041] FIG. 15 is a line drawing evidencing an alternate embodiment of frame assembly, utilizing spherical units in combination with the tetrahedral-octahedral honeycomb structure.

DETAILED DESCRIPTION OF THE INVENTION

[0042] The invention comprises a modular space frame with multiple rigid components tied together using a flexible frame, wherein the flexible structure maintains its strength along the same lines of strength as the rigid structures. A force applied along a vector through the rigid frame will be transferred into the flexible frame and distributed evenly across the flexible frame.

[0043] Levels of flexibility and rigidity within the frame can be varied, either by choice of materials or the thickness thereof. Not only can the flexible frame provided act as a hinge or joint, but it can also act as a cushion or shock absorber between two or more rigid components.

[0044] This method of flexible space-frame construction allows for the use of a single modular part to construct an entire frame, one embodiment of which is pictured in FIG. 1. This method employs the use of one part repeated many times to produce a structure which is strong, lightweight and flexible. The method of construction for this frame is by means of snap fit parts. For example, six identical cross-shaped members can form one sphere-shaped grouping. The frame can be constructed without the use of glue, weld joints, non-integrated pins, screws or other permanent or non permanent fasteners. That said, the use of any such fastening mechanisms is available to achieve an increased level of adhesive strength, as required.

[0045] Each cross-shaped member snaps in place to other like members by fitting the two connector piece assembly components together. As used in describing the invention, pins shall be understood to be protrusions, usually cylindrical, integrated into the larger structure of a cross-shaped member for the purpose of attaching to other such members. The connecting pins of one member align to the holes of the other. The two are then squeezed together and either (1) align the larger components for attachment by a secondary mechanism, such as part 70 pictured in FIG. 6, or (2) snap into place once fully inserted.

[0046] Six such cross-shaped members can be aligned, bent and connected into a plurality of designs, each comprising a unit. Examples of such unit designs are a rough spherical unit 50 with six convex surfaces, a reverse unit 51 with six concave surfaces, an open-topped spherical unit 52.

[0047] In the spherical unit example, two spheres can be aligned at any of twelve connector piece assemblies 39, located at intervals around the sphere. These alignment points allow the two spheres to be attached together. By again aligning the pins and the holes, the two units can be brought together. The two spheres can be secured in place by attaching overlocking construction blocks 70 at the point of intersection (see, FIG. 7). The same means of attachment are available to the other unit designs, and more units can then be added to build large strong structures of any desired configuration. A fully-constructed frame may utilize only a single unit design, or may incorporate two or more such designs. The resulting frame structure can remain flexible while simultaneously allowing for connector rods to be added and secured in various methods to add high rigidity to specific areas within flexible structure.

[0048] This method of space frame construction employs a rigid method of space frame construction in conjunction with and attaches to the flexible frame as described herein above. The disclosed method employs the use of one part repeated many times to produce a structure which is strong, lightweight and rigid. Another cross-shaped member that is different from that used above is used for the manufacture of a 12-pointed (6 channel) star shaped node. In this case, three cross-shaped members, all of the same shape and size, are joined to form one 12-pointed star shaped node. This star shaped node is then used in conjunction with wooden, plastic, metal and/or carbon fiber rods to form up a rigid space frame by the use of snap-fit mechanisms which are integrated into the design. This rigid frame can optionally be constructed without the use of glue, weld joints, non-integrated pins, screws or other permanent fasteners. Each cross-shaped member is made up of two c-channels. The c-channels are designed to allow flexible or semi-flexible rods to be snapped into or inserted from the end into the channel. Typical materials of the flexible or semi-flexible rods would be made up of wood, plastic, metal, fiberglass or carbon fiber, or other, similar materials exhibiting a varied degree of rigidity and durability while also allowing for flexibility. Materials for the flexible or semi-flexible rods will be chosen and/or mixed to account for the degree of flexibility desired and the level of stress expected on a given construction. The purpose of the node, for example as pictured in FIG. 10, is to allow a user to weave semi-flexible rods into a space frame. Friction holds the rods in place and keeps them from slipping axially, while forming a rigid space frame that is then used either by itself or in conjunction with the other frames as described herein.

[0049] Applicant's disclosed manufacturing method prevents the need for a complicated mold and manufacturing processes which can add costs to the end product. Since the final product results in a 12-sided shape, an injection-molding or similar process would require a 12-sided mold and a specialized and complex manufacturing process. Thus, a cost-effective manufacturing process as described herein will have great market utility.

[0050] The disclosed method offers simplicity such that unskilled workers will be able to install and assemble the frame quickly and easily. There are few if any tools required for assembly when the units are relatively small in size. As such, units up to a certain size can be assembled without tools, welding or adhesives, and disassembly is similarly simple with few or no tools needed.

[0051] Shape memory metal alloys (SMAs) and shape memory polymers (SMPs) are known that would provide the desired flexibility to components of the space frame invention, preferably the cross pieces and/or arms of the cross-shaped members. SMAs such as nickel-titanium, nickel-aluminum, copper-aluminum-nickel, beta titanium alloys such as TiNb, TiMo or TiV, beta brass alloys such as CuZnAl, are currently in use in the industries of medical devices, robotics, industrial design and, increasingly, construction. Flexible space frame components made of SMAs could exhibit either one-way or two-way memory effects. In the latter case, the components could be stored and transported at one temperature with a shape providing for ease of storage and movement, with such components then displaying a different, second shape when deployed at a second temperature, such as the extreme cold of outer space.

[0052] Several known polymer and copolymer types exhibit shape memory properties and may be useful for producing cross-shaped members. Probably the best known and best researched SMP is polyurethane polymer, but also known are crosslinked polyethylene homopolymer, styrene-butadiene thermoplastic copolymer, polyisoprene, the class of copolymers including stearyl acrylate and acrylic acid or methyl acrylate, as well as norbornene or dimethaneoctahydronapthalene homopolymers or copolymers, and styrene copolymer.

[0053] SMPs and SMAs have been the subject of commercial development in the last 20 years. SMPs derive their name from their inherent ability to return to their original memorized shape after undergoing a shape deformation. In the present invention, the use of an SMA or SMP to manufacture the belt-like configurations of cross-shaped members will allow those members to bend, twist or otherwise deform within their unit structures to absorb an application of force that might otherwise damage or destroy the larger frame, but then return to their original configurations to maintain the frame integrity after any such shock occurs.

[0054] Construction of Applicant's frame components may occur by use of injection molding, three-dimensional printing, or similar techniques used commercially for metals and plastics.

[0055] The final structure can have an infinite arrangement and therefore allow for the final structure to have a plurality of shapes.

[0056] One embodiment is a structure is based on a face centered cubic lattice of spheres and a tetrahedral-octahedral honeycomb of straight lattices and an arrangement with the diameter of each node being equal, it forms a space filling arrangement of spheres interconnected with a lattice of tetrahedral-octahedral honeycombs, which can be manufactured with the use of three-dimensional printing techniques. (See, e.g., FIGS. 12 and 14). The final structure can fill free space without running into itself. It is possible to join two adjacent rigid space frames of the similar tetrahedral-octahedral honeycomb design together with a flexible frame. These two rigid frames would then have the advantage of being joined while at the same time move or sway independently. For example, this could be used when joining two floating rigid structures. Finally, two rigid structures could be joined and allowed to shift independently while remaining joined.

[0057] The ease of tool-free assembly means that frame structures may be constructed on-site without the need for large-scale prefabrication, even in difficult environments. This will allow the frames to remain in modular form during transportation, where they can be usefully stacked and stowed. Similarly, the units of the frame may be disassembled by unsnapping, requiring few or no tools. Thus, the ease of maintenance of a frame-on site will be enhanced, as single units may be removed and replaced and entire frames reconfigured with minimal difficulty.

[0058] The ease of construction and reconfiguration of a frame structure provides capability to change the frame shape or to change units of one material or type with units of another as needed.

[0059] In order to prevent the units of the larger frame from pulling apart, shape memory materials will sometimes be inappropriate for manufacture of the connector pieces. In another embodiment, the connector pieces will be made of a known hard alloy, ceramic, polymer or copolymer, and connected to each arm end via a known process of integration such as via adhesive, welding or similar stress-resistant method of attachment.

[0060] If either nitinol or piezoelectric crystals are introduced along one direction of the final structure then the structure can bend with a change in temperature or electrical current. This feature can provide a multitude of applications ranging from lifts, and joints to large mechanical muscles. It is preferred to use piezoelectric crystals within the matrix as a means to introduce mechanical control of the matrix. Piezoelectric crystals are known and used in industry because of their unique capability to change shape, deform, warp, shrink or expand when an electric current is applied. This property of the crystals is not only useful for the purpose of changing shape, in addition the crystals apparently exhibit intense force comparable for their size and weight. So a small crystal can lift several times its own weight without permanent degradation of its structure. On the downside, these crystals have limited movement and shape deformation characteristics which limit their usefulness as mechanical muscles in. However, they have found their way into many other technologies. Presently, they are used in printers, copiers, telecommunications, pneumatics and a variety of other technologies. The present invention introduces a new application for these crystals which will allow their use in mechanical muscles.

[0061] The invention can produce a large flexible frame with the use of sites throughout its structure. A site is created at any point where flexibility can be observed and where a piezoelectric crystal can be attached between two points. Piezoelectric crystals can optionally be introduced per the designer's requirements. When introduced into the structure, the piezoelectric crystals are attached and secured to the structure. Wires connect the crystals to a power source and a control center wherein electricity can be introduced to the crystals at those locations to where movement is needed. The powered piezoelectric crystal will then pull or push on the frame to initiate a bending, twisting, shrinking or expansion of the entire frame. The resulting structure will have the ability to lift or move a significant amount of mass without the need for complicated and heavy hydraulics, pneumatics, gears, shifters, relays, motors and shafts. Furthermore, the sensitive crystal is protected by the flexible cushioning nature of the frame, so a crystal will not be at significant risk of damage from over applied force.

[0062] The resulting frame will now have the properties of being lightweight, flexible, maneuverable, easily constructed, and finally the ability to act as a mechanical muscle. Additionally, because we can introduce rigidity into any part of the frame as we desire the frame can also have the property of being a simulated bone. So, the resultant structure will have system of mechanical muscles along with rigid skeletal system and the ability to attach the two systems together, allowing the complete structure to perform similarly to that of an integrated musculoskeletal system with all the properties thereof.

[0063] Electrical power sources for piezoelectric crystals may be taken from known commercial technology, notably alkaline batteries, lithium ion or other known chemical batteries, solar panels or any other known power source that can be sized and mounted appropriately on the frame.

[0064] A space frame for use in a space-station could be used as means of storage while at the same time providing protection from the elements of space. For instance, a flexible frame which has the natural shape of a sphere could provide a means of holding an array of spherical tanks, providing compartmentalization similar to that used in large oceangoing vessels. If this array is used to hold water, fuel, and food then the extra mass added to the frame would help protect the space station from the impact of a small meteor or perhaps radiation. If damage did occur it would be localized to a small region which could easily be repaired. Losses would be minor as the lost cargo would be limited to the vessels which were hit while the remaining vessels remain intact. A similar incident to a larger tank would result in a complete loss of the contents of the entire vessel.

[0065] The invention as described herein contrasts from known frame technology in that is exhibits a high degree of flexibility along axial lines. For example, the disclosed units will deform to absorb the stress of a force applied axially along one of the connector rods or radially across the frame, before reverting to its original configuration due to its shape memory components. Further, the method of construction differs from known technology in that the cross-shaped members bend like a spring and are attached together at the tips, whereas known designs require slots cut into the base, fasteners like pins, bolts or screws, or similar means of attachment. As such, this frame allows the units of any configuration to be joined directly to each other without the need for connection rods, pins or other separate connecting components. The inherent flexibility of the larger frame will also compensate for any minor misalignments or defects in the components themselves.

[0066] Applicant's frame flexibility also allows for the frame to bend while being assembled, further adding to ease of construction. Because this frame utilizes one repeat unit that can be made rapidly, with known techniques, and units can be stowed efficiently and assembled on site, the frame is less costly to manufacture, distribute, assemble and maintain. Additional pieces would require more molds, additional packaging and increase end costs.

DETAILED DESCRIPTION OF THE FIGURES

[0067] FIG. 1 is a drawing of the ventral side of a cross-shaped member 20 with a cross piece 21 in the center with four equidistant arms 23, each extending outward towards a connector piece 30, located at each of four arm ends 21. Each connector piece is roughly rectangular, with a proximal surface 30a and distal surface 30b, two side surfaces 30c, as well as dorsal face 30d (obscured) and a ventral face 30e. Each arm ends 21 is used to connect to another cross-shaped member 20 or other fittings designed for a variety of uses. Each connector piece 30 is raised above its corresponding arm 23 in the ventral direction, and each comprises a distal connecting pin 31 extending from the distal surface 30b of the connector piece and a distal connecting hole 32 for receiving the distal connecting pin of another connector piece, with such distal connecting pin 31 comprising a ledge 31a and an angled edge 31b for connecting to another connector piece by snap-fit. Each connector piece also comprises a pair of complementary pins and holes consisting of tall and short side alignment pins, 33 and 35, respectively, and tall and short side alignment holes, 36 and 34, respectively, arranged on the ventral face 30e also for alignment of the connector pieces, as well as a channel 37, semicircular protrusion on each side surface side. The cross-shaped member 20 can be manufactured by a plastic injection mold or by 3D printing.

[0068] FIG. 2 shows a cross-shaped member of the dorsal side of the cross-shaped member 20 pictured in FIG. 1. In particular, the dorsal face 30d of each connector piece 30 is pictured, evidencing the opening in such dorsal face of each of the short and tall side alignment holes, 34 and 36, respectively.

[0069] FIG. 3 shows two connector pieces 30 initiating a snap-fit connection whereby each connector piece's distal connecting pin 31 is being inserted into the opposite connector piece's distal connecting hole.

[0070] FIG. 4 shows two connector pieces 30 with a two single barrel crimping sleeves 61 emanating from each side, and a connector rod 60 inserted through crimping sleeve holes not pictured). The collet mechanism is fully pictured in FIG. 10. In an alternate embodiment, adhesives, heat shrinking or welding could be used instead of crimping sleeves. Crimping sleeves are not absolutely necessary unless positive control between flexible and rigid frame connection is required. For instance, if the connection point is between two floating platforms, then the designer may use crimping sleeves to allow for freedom of movement at the joints.

[0071] FIG. 5A shows a fully-formed spherical unit 50, comprising six cross-shaped members 20 wherein each such member connects to four other cross-shaped members using the distal connecting pins 31 and distal connecting holes 32 on its four connector pieces 30, thereby creating six convex cross-shaped surfaces, which together roughly approximate a sphere. In this configuration, the ventral faces 30e of each connector piece are facing outward while the dorsal faces 30d are facing inward. In this configuration, twelve connector piece assemblies 39 are formed, each comprising two connector pieces 30, with the short and tall connecting pins 33, 35 and short and tall connecting holes 34,36 located on each connector piece's ventral face 30e are left facing outward. This design allows the further connection of the spherical unit 50 with other units.

[0072] FIG. 5B shows an alternate configuration to the spherical unit of FIG. 4A, in which the six cross-shaped members' 20 connector pieces 30 are interlocked using the short and tall connecting pins 33,35 and short and tall connecting holes 34,36 located on each connector piece's ventral face 30e (all such connecting parts obscured). The resulting reverse unit 51 comprises six cross-shaped concave surfaces, together forming a starburst-shaped formation with twelve connector piece assemblies 39 forming points, each comprising two interlocking connector pieces 30 and featuring two outward-facing distal connecting pins 31 and distal connecting holes 32, enabling the further connection of the reverse unit 51 with other units.

[0073] FIG. 6 provides a close-up view of the connector piece assemblies 39 of two separate spherical units 50 as they approach to interlock, with arrows indicating the interlocking snap fit of each connector piece assembly's short and tall connecting holes 34,36 with the corresponding short and tall connecting pins 33,35 of the opposite connector piece assembly. The listed pins and holes provide alignment of the connector piece assemblies, which are then locked together using overlocking blocks 70, as pictured in FIG. 7, for example.

[0074] FIG. 7 shows two spherical units 50 connected by the process pictured in FIG. 5.

[0075] FIG. 8 shows an alternate frame embodiment wherein a plurality of spherical units 50 are connected to other partially formed, open-toped spherical units 52. Open-topped spherical units 52 are formed from five cross-piece members 20 instead of six, with one cross-piece member 20 being left out of an open-topped spherical unit, each such cross-piece member remains unsecured within the unit itself, thus leaving an open top 52a. As pictured, multiple open-topped spherical units are interconnected using the snap fit design of their respective connector piece assemblies 39, which connector piece assemblies are fixed in place using overlocking blocks 70.

[0076] FIG. 9 shows a single helical cross-shaped member 41 with a c-channel 44 cut along the axis into the each of the helical cross-member arms 42. The figure also shows an interface joint 45 and grooves 43 which allow for the insertion of other like cross-shaped members. The interface joint 45 is the part which receives other like cross-shaped members. All three like members are aligned and set along this axis. The grooves 43 that are notched perpendicularly to the arms 42 of the member so that each groove aligns with a groove of another like member. These grooves are specifically shaped to removably snap into and hold other like members' arms.

[0077] FIG. 10 shows and exploded view of the node 40. Such node is comprised of helical three cross-shaped members 41, all of which join at each of the other two joints. These three cross-shaped members are then locked into place utilizing a snap-fit mechanism, whereby light tension is applied to the arms of one member each such snap-fit mechanism embodied in an interlocking groove 43. A helical cross-member ledge 46 located at the edge of each groove to prevent unintentional disengagement of the interlocked members.

[0078] FIG. 11 shows a fully formed node 40. Each 12-pointed node has six channels, including three inner channels 47 and three outer channels 48, all of which are directionally diverted around one the central point of intersection 49. This node is held together by snap-fit mechanisms, which allow each node to be subsequently taken apart and broken down into its component pieces. However, if necessary, the node can be permanently secured by the use of glues, adhesives or welding.

[0079] FIG. 12 shows a set of six nodes 40 along with connecting rods 60 joined together to form a tetrahedral-octahedral honeycomb structure. Each node has a total of six connecting rods running through each of the six channels 47,48. Rods can run the length of the structure and penetrate through several nodes. The gap in the c-channels 44 is significantly smaller than the diameter of the rods. Rods can therefore be pressed and snapped into the channel. Friction prevents the nodes from slipping axially through the nodes. The twisting curvature of the channels provides significant friction when the rods try to move axially along the channels. This friction thus prevents the movement of the rods axially, however some freedom of axial movement can occur. To fix the rod and prevent any axial movement, two crimping sleeves 61 can be crimped onto the connecting rod 60, one such sleeve at the end of each arm. The use of the crimping sleeves is at the discretion of the designer or engineer, but are not absolutely necessary.

[0080] FIG. 13 shows a frame consisting of a plurality of interlocking units as described herein, including spherical units 50, reverse units 51 and connector rod-holding nodes 40.

[0081] FIG. 14 shows the same frame in FIG. 13 along with two piezo-electric crystals. One crystal is installed into the frame, the other is being installed into the frame at a site. In this case, the site is between two adjacent connector piece assemblies 39 and is denoted by a hollow rectangular cuboid. shows an alternate configuration consisting of six interlocking cross-shaped members 20 which, when interconnected, will form a spherical unit 50.

[0082] FIG. 15 shows an alternate embodiment of a plurality of spherical units 50 arranged within octahedral units 54, forming a honeycombed frame acting as a single structure with properties of both flexibility and rigidity.

LIST OF REFERENCE NUMBERS

[0083] 10 Frame System [0084] 20 Cross-shaped member [0085] 21 Arm end [0086] 22 Cross piece [0087] 23 Arm [0088] 30 Connector piece [0089] 30a proximal surface [0090] 30b distal surface [0091] 30c side surfaces [0092] 30d dorsal face [0093] 30e ventral face [0094] 31 Distal connecting pin [0095] 31a Ledge [0096] 31b Angled edge [0097] 32 Distal connecting hole [0098] 33 Side alignment pin (tall) [0099] 34 Side alignment hole (short) [0100] 35 Side alignment pin (short) [0101] 36 Side alignment hole (tall) [0102] 37 Channel [0103] 37a Rod hole [0104] 38 Semicircular protrusion [0105] 39 Connector piece assembly [0106] 40 Node [0107] 41 Helical cross-member [0108] 42 Helical cross-member arm [0109] 43 Groove [0110] 44 C-channel [0111] 45 Interface joint [0112] 46 Helical cross-member ledge [0113] 47 Inner channel [0114] 48 Outer channel [0115] 49 Point of intersection [0116] 50 Spherical unit [0117] 51 Reverse unit [0118] 52 Open-topped spherical unit [0119] 52a Open top [0120] 53 Starburst unit [0121] 54 Octahedral unit [0122] 60 Connector rod [0123] 61 Crimping sleeve [0124] 70 overlocking block

[0125] The references recited herein are incorporated herein in their entirety, particularly as they relate to teaching the level of ordinary skill in this art and for any disclosure necessary for the commoner understanding of the subject matter of the claimed invention. It will be clear to a person of ordinary skill in the art that the above embodiments may be altered or that insubstantial changes may be made without departing from the scope of the invention. Accordingly, the scope of the invention is determined by the scope of the following claims and their equitable equivalents.