Compliant biomimetic endcap system for tensegrity structure assembly

Abstract

A tensegrity structure assembly includes a plurality of compression members, a plurality of tension members, and a plurality of endcaps. At least one endcap is coupled to at least one of the compression members. At least one tension member is mechanically attached to at least one endcap.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of and priority to U.S. Provisional Application No. 63 / 771,483, filed Mar. 13, 2025, the entire contents of which are hereby incorporated by reference herein.BACKGROUND

[0002] The present disclosure relates generally to tensegrity structures and assembly methods. More specifically, the present disclosure relates to a compliant, biomimetic endcap system. Traditional assembly methods for tensegrity structures involve complex assembly procedures, difficulty in achieving consistent tension, and limited adaptability once assembled.SUMMARY

[0003] One embodiment of the present disclosure relates to an assembled tensegrity structure including a plurality of tensile members, a plurality of compression members, and an endcap. The endcap is a connection point between each tensile member and each compression member. The endcap is secured to one end of a compression member and receives a portion of a compression member. This method of assembly is repeated until a tensegrity structure is assembled in its entirety. The tensegrity structure does not require any tools for assembly and is assembled by hand.

[0004] Another embodiment of the present disclosure relates to a novel compliant endcap system for tensegrity structures. The system features elastomeric endcaps with a biomimetic hand-like gripping mechanism that self-secures to tensile members through a combination of material elasticity and geometric engineering.

[0005] In some embodiments, the tensegrity structure comprises a compliant endcap fabricated from elastomeric materials designed to resemble a human hand with upper “fingers” and a lower “thumb knuckle” creating a channel dimensioned to accommodate a tensile member.

[0006] In some embodiments, the tensegrity structure comprises a compliant endcap fabricated from elastomeric materials, designed with a fixed channel dimensioned to accommodate a tensile member and an attached flap. The attached flap is configured to open to receive the tensile member and close to secure the tensile member in place.

[0007] In some embodiments, the tensegrity structure comprises a compliant endcap fabricated from elastomeric materials, designed with a fixed channel dimensioned to accommodate a tensile member and an attached upper element that is fixed in place. The tensile member is inserted into the fixed channel and secured by the upper element.

[0008] In some embodiments, the tensegrity structure comprises a compliant endcap fabricated from elastomeric materials, designed with a fixed channel to accommodate a slack tensile member. The slack tensile member is wrapped around a groove barrel, with the tensile member placed between each groove. A strut located below the groove barrel is rotated clockwise while an upper element located above the groove barrel is rotated counterclockwise to create tension within the slack tensile member. A detent for the groove barrel resists backwards motion of the barrel to keep the tensile member secure.

[0009] In some embodiments, the compliant endcap consists of a plurality of detent cavities configured to secure an end of the tensile member.

[0010] Another embodiment of the present disclosure relates to a tension member configured to be coupled to an endcap within a tensegrity structure assembly.

[0011] In some embodiments, the tensile member includes strategically positioned expanded diameters (“humps”) that function as a safety mechanism, causing automatic release when excessive tension is encountered.

[0012] In some embodiments, the tensile member incorporates an internal constraint mechanism consisting of a flexible, inelastic filament traversing through an elastic outer material, creating a composite structure with controlled flexibility and definitive maximum extension limits.BRIEF DESCRIPTION OF THE FIGURES

[0013] FIG. 1 is a perspective view of a portion of an assembled tensegrity structure, according to an embodiment.

[0014] FIG. 2 is a perspective view of a portion of an assembled tensegrity structure, according to another embodiment.

[0015] FIG. 3 is a side cross-sectional view of an endcap shown in the tensegrity structure of FIG. 1.

[0016] FIG. 4 is a side cross-sectional view of the endcap shown in the tensegrity structure of FIG. 1, shown receiving a tension member, according to an embodiment.

[0017] FIG. 5 is a side view of a portion of an assembled tensegrity structure, according to another embodiment.

[0018] FIG. 6 is a side cross-sectional view of a tensile member, according to an embodiment.

[0019] FIG. 7 is a perspective view of an endcap, shown releasing the tension member shown in FIG. 5 and FIG. 6, according to an embodiment.

[0020] FIG. 8 is a perspective view of an endcap, according to another embodiment.

[0021] FIG. 9 is a perspective view of an endcap, according to another embodiment.

[0022] FIG. 10A is a side cross-sectional view of an endcap, according to another embodiment.

[0023] FIG. 10B is a side cross-sectional view of an endcap, according to another embodiment.

[0024] FIG. 11A is a side cross-sectional view of an endcap, according to another embodiment.

[0025] FIG. 11B is a side view of an endcap, according to another embodiment.

[0026] FIG. 12 is a perspective view of an assembled tensegrity structure, according to an embodiment.DETAILED DESCRIPTION

[0027] Tensegrity structure assemblies combine compression elements (i.e. struts, etc.) and tension members (i.e. cables, etc.) in a self-balancing system where elements are held in position by the tension network. In some embodiments, the tensegrity structure assembly includes a plurality of endcaps. The endcap functions as a self-securing connector that attaches to compression elements within the tensegrity structure. The endcaps elastic properties and method of securement allow for temporary deformation during installation while providing sufficient retention force during normal operation. In some embodiments, the endcap may include additional components to secure the tensile member in place.

[0028] Some implementations comprise a compliant endcap mechanism fabricated from elastomeric materials such as thermoplastic polyurethane (TPU) or similar flexible polymers. The endcap components may be fabricated from a range of elastomeric materials including at least one of the following: thermoplastic polyurethane (TPU) of varying durometer ratings, thermoplastic elastomers (TPE), silicone-based polymers, flexible polyamides, and styrenic block copolymers. The durometer (hardness) of the material typically ranges from 70 A to 95 A on the Shore hardness scale.

[0029] Referring generally to the Figures, various embodiments of a tensegrity structure are shown, in addition to a tension member and an endcap. A plurality of compression elements and a plurality of tension members are supported by a plurality of endcaps within the tensegrity structure. An endcap is secured to an end of a compression element. A tension member is placed into an interface of an endcap to create a continuous network around a plurality of compression elements. A tension member defines the spatial position of each compression element and is configured to maintain consistent tension within the tensegrity structure. Unlike rigid connection systems that require precise alignment, this assembly system accommodates a range of insertion angles, making assembly significantly more intuitive and user-friendly, particularly for novice users.

[0030] Referring to FIGS. 1-2, a portion of an assembled tensegrity structure 100 including a plurality of endcaps 101, a plurality of compression elements 102, and a plurality of tension members 103 is shown, according to an embodiment. The endcap 101 includes a fixed channel 104 configured to accommodate a tension member 103.

[0031] In some embodiments, the tension member 103 includes two components: a membrane span 105 and a terminal span 106. The membrane span 105 is a long structural element configured to create continuous tension throughout the tensegrity structure 100. The terminal span 106 is a short structural element configured to connect to the compression element 102 via an endcap 101. The terminal span 106 creates a segment of local tension and connects the compression element 102 to the remaining tensegrity structure 100.

[0032] Referring to FIG. 3, in some embodiments, the endcap 101 is designed to resemble a carabiner like gripping mechanism with a human hand like functionality. The endcap 101 comprises an upper gripping element 107 analogous to fingers and a lower securing element 108 resembling a thumb knuckle. The channel 104 is located between the upper gripping element 107 and the lower securing element 108. The channel 104 width corresponds precisely to the diameter of the intended tensile member, creating optimal retention force through surface tension and material elasticity.

[0033] Referring to FIG. 4, in some embodiments, installation of the endcap 101 onto a tension member 103 is achieved through a perpendicular application of force similar to a carabiner mechanism, wherein the tension member 103 temporarily deforms, from a baseline state to a deformed state, the upper gripping element 107, and or the lower securing element 108, as it enters the channel 104. Once the tension member 103 is fully inserted into the channel 104, the tension member 103 is secured by the lower securing element 108 and the upper gripping element returning to a baseline state. The upper gripping element 107 returns to its original position, completing the carabiner-like closure action.

[0034] This connection relies on biotensegrity principles, utilizing surface tension forces rather than mechanical fasteners. The contact point at the “thumb pit” area serves to distribute forces appropriately throughout the connection, eliminating stress concentrations that could lead to component failure.

[0035] Referring to FIGS. 5-6, in some embodiments, the tension member 103 includes a plurality of expanded sections 109, or “humps” that may vary in diameter and are strategically positioned along the length of the tension member 103. The spacing between the expanded sections 109 is calculated based on the optimal distribution of connection points, or endcaps 101, in a tensegrity structure 100. This ensures balanced tension throughout the assembled tensegrity structure 100.

[0036] In some embodiments, an expanded section 109 is created through localized material variations, geometric modifications to the cross-section, additive components affixed to the span, or molded protrusions integral to the span design.

[0037] The expanded section 109 includes an inelastic filament 110 that traverses through the center of both the expanded section 109 and the tension member 103. The expanded section 109 also includes an elastic outer portion 111 that encompasses the inelastic filament 110. The inelastic filament 110 is positioned centrally within the elastic outer portion 111 to create an expanded section 109 with composite tensile elements and dual mechanical characteristics. The elastic outer portion 111 provides initial compliance and energy absorption when tension is applied to the tension member 103, and the inelastic filament 110 establishes a definitive maximum extension limit to prevent overloading the endcaps 101 that act as connection points to the assembled tensegrity structure 100. This dual-material construction provides a construct with varying degrees of elasticity that work in concert to provide flexibility and structural limitation. The result is a tension member 103 that exhibits progressive resistance to elongation. The tension member 103 is initially compliant but becomes increasingly resistant as it approaches its maximum engineered extension limit.

[0038] The inelastic filament 110 prevents elongation beyond a predetermined maximum length. This dual-material approach controls flexibility within the tensegrity structure assembly 100 and maintains structural integrity under variable loading conditions.

[0039] In some embodiments, the inelastic filament 110 may be composed of high-tensile materials such as aramid fibers, carbon fibers, or specialized polymer strands with minimal elongation material properties.

[0040] Referring to FIG. 7, in some embodiments, an endcap 101 can encounter an expanded section 109 during movement along the tension member 103. This will cause the upper gripping element 107 and the lower securing element 108 to deform beyond their functional range and result in automatic disengagement. This is an added safety feature to prevent excessive tensile loading through means of an automatic release mechanism. This feature prevents plastic deformation of components by ensuring no single connection point experiences forces exceeding design parameters.

[0041] The force threshold that triggers automatic release is engineered through the specific dimensions of the expanded sections 109 of the tension member 103, the upper gripping element 107, and the lower securing element 108 of the endcap 101. This threshold can be customized through variations in material durometer, channel 104 dimensions, and the diameter differential between the standard tension member 103 and its expanded sections 109.

[0042] Manual disengagement is achieved through either a twisting motion that leverages the compliant nature of the material or by manually lifting the upper gripping element 107 to creates an egress path for the tension member 103 along its original entry route.

[0043] Referring to FIG. 8, in some embodiments, the endcap 101 includes an attached flap 112 that extends in a first, open position extending perpendicular to the endcap 101. The channel 104 receives a tension member 103 while the attached flap 112 is in first position. Once the tension member 103 is in place, the attached flap 112 extends in a second, closed position extending parallel to the endcap 101, and is inserted into an opening 113. The second position secures the tension member 103 within the endcap 101.

[0044] In some embodiments, a second opening 114 is defined for a press-fit connection with a compression element 102.

[0045] Referring to FIG. 9, in some embodiments, the endcap 101 includes an upper gripping element 107 and a lower securing element 108 of various geometries that are fixed in place.

[0046] Referring to FIGS. 10A and 10B, in some embodiments, the slack tension member 103 is inserted into the channel 104 of the endcap 101, as shown in FIG. 10A. The tension member 103 is then wrapped around a groove barrel 117 and the tension member 103 is placed between each individual groove. A strut 116 located below the groove barrel 117 is rotated clockwise while an upper element 118 located above the groove barrel 117 is rotated counterclockwise to create tension within the slack tension member 103. A detent 115 carved within the groove barrel 117 resists backwards motion of the barrel. This keeps the tension member 103 secure within the groove barrel 117.

[0047] In some embodiments, a second channel 119 is defined to receive a tension member 103. This tension member 103 is secured in place by the geometry of the second channel 119.

[0048] Referring to FIGS. 11A and 11B, in some embodiments, the endcap 101 includes a plurality of cavities 120 to secure an anchor 121 attached to an end of a tension member 103. The tension member 103 can either be positioned through the channel 104 or wrapped around the endcap 101. Additionally, the anchor 121 can utilize a single cavity 120 or a plurality of cavities 120 for proper securement.

[0049] Referring to FIG. 12, the tensegrity structure assembly 100 may incorporate a secondary retention cap 131 in the form of a supplemental cap or collar that enhances the retention capability of the primary gripping mechanism. This removable or sliding retention cap 131 may be positioned over the endcap's 101 gripping mechanism after the tension member 103 is secured. The retention cap 131 is designed to prevent the inadvertent opening of the upper gripping element 107 and the lower securing element 108 during dynamic loading conditions, distribute force mor evenly, provide additional protection against lateral displacement of the tension member 103, and increase the overall retention force of the connection without compromising the safety release function.

[0050] The retention cap 131 may be fabricated from the same elastomeric materials as the endcap 101 or from alternative materials selected for complementary mechanical properties. It may attach to the endcap 101 through various mechanisms including friction fit, snap-fit engagement, sliding collar, threaded engagement, or bayonet-style twist-lock mechanism.

[0051] This design facilitates rapid assembly of tensegrity structures through a simplified installation motion similar to that of a carabiner, wherein the user applies perpendicular pressure to position the endcap 101 onto the tension member 103. This action causes temporary deformation of the compliant mechanism, followed by a spring-back action that secures the connection. Multiple connections can be sequentially established to create a complete tensegrity structure assembly 100, as depicted in FIG. 12.

[0052] The system achieves stability through self-regulation of tension, as the compression elements 102 apply pressure at connection points where the tension members 103 are held. The geometric arrangement of these connection points maintains equilibrium throughout the structure according to tensegrity principles.

[0053] Assembly can be completed without specialized tools, making the system accessible to users with varying levels of expertise. The compliant nature of the connection mechanism compensates for minor misalignments during assembly, further enhancing user-friendliness. The assembly system encompasses multiple methodologies for connecting the tension member 103 to the endcap 101, providing flexibility in manufacturing and assembly.

[0054] In some embodiments, the tension member 103 may be integrally formed with the endcap 101 as a single, continuous component through multi-material molding, co-extrusion, or similar manufacturing processes. This approach eliminates potential failure points at the junction between the tension member 103 and endcap 101.

[0055] In some embodiments, the tension member 103 may be mechanically coupled to the endcap 101 through various means, including press-fit connections into a receiving channel in the endcap 101, mechanical interlocking features such as barbs or expanded sections 109, and tension-distributing geometries that prevent stress concentration at the junction point.

[0056] In some embodiments, the tension member 103 may be chemically bonded to the endcap 101 using compatible adhesives selected to maintain flexibility at the junction while providing sufficient tensile strength to prevent separation under load.

[0057] In some embodiments, the tension member 103 may be connected to the endcap 101 through a combination of the above methods, such as a mechanical interlock supplemented by adhesive bonding, to provide redundant securing mechanisms.

[0058] This design offers significant advantages by eliminating the need for specialized tools, reducing assembly time, and providing a self-regulating tension system. The compliant mechanism accommodates minor variations in tensile member dimensions while maintaining secure connections within design parameters. Additionally, the automatic release feature serves as an inherent safety mechanism that prevents component failure due to excessive loading.

[0059] The tensegrity structure assembly, of which various embodiments are disclosed herein, provide several advantages over existing devices. Some implementations enable both rapid assembly and rapid disassembly of tensegrity structures. This bidirectional efficiency allows users to easily correct assembly mistakes without compromising structural integrity. Furthermore, the system facilitates reconfiguration of existing tensegrity structures when additional members need to be integrated, a process that traditionally requires complete disassembly and reassembly with conventional connection methods. This adaptability significantly enhances the practical utility of tensegrity structures in applications requiring iterative design adjustments or modular expansion.

[0060] As utilized herein with respect to numerical ranges, the terms “approximately,”“about,”“substantially,” and similar terms generally mean + / −10% of the disclosed values. When the terms “approximately,”“about,”“substantially,” and similar terms are applied to a structural feature (e.g., to describe its shape, size, orientation, direction, etc.), these terms are meant to cover minor variations in structure that may result from, for example, the manufacturing or assembly process and are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the disclosure as recited in the appended claims.

[0061] The terms “coupled,”“connected,” and the like, as used herein, mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members, or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another.

[0062] References herein to the positions of elements (e.g., “top,”“bottom,”“above,”“below,” etc.) are merely used to describe the orientation of various elements in the Figures. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure.

[0063] It is important to note that the construction and arrangement of the tensegrity structure assembly as shown in the various exemplary embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments.

[0064] Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present application. For example, any element disclosed in one embodiment may be incorporated or utilized with any other embodiment disclosed herein. Also, for example, the order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating configuration, and arrangement of the preferred and other exemplary embodiments without departing from the scope of the appended claims.

Claims

1. A tensegrity structure assembly comprising:a plurality of compression members;a plurality of tension members; andan endcap coupled to at least one end of the plurality of compression members, the endcap comprising:a body;a portion attached to an end of the body, the portion comprising a gripping element, wherein a space located between the gripping element and the body defines an open channel configured to receive a tension member of the plurality of tension members.

2. The tensegrity structure assembly of claim 1, wherein the gripping element of the portion comprises an upper gripping element and further wherein the portion comprises a lower securing element.

3. The portion of claim 2, wherein the upper gripping element has a deformed state during installation of the tension member and a baseline position that secures the tension member.

4. The portion of claim 2, wherein the lower securing element is configured to position around the tension member and secure the tension member.

5. The portion of claim 2, further comprising an element coupled to the endcap configured to transition from a first open position extending perpendicular to the endcap to a second, closed position extending parallel to the endcap.

6. The portion of claim 2, further comprising a stationary element configured to secure the tension member.

7. The portion of claim 2, further comprising a plurality of cavities configured to secure the tension member.

8. The portion of claim 2, further comprising a groove barrel configured to receive the tension member and a strut element engaged with the tension member by rotational tension to secure the tension member.

9. The portion of claim 2, further comprising a detent element configured to releasably engage a groove located on a groove barrel, wherein a rotated position of a groove barrel is maintained after rotational tension is applied to the endcap when the detent element is engaged with the groove.

10. The tensegrity structure assembly of claim 1, wherein the endcap comprises a secondary removable cap configured to position over the gripping element after the tension member is secure.

11. The tensegrity structure assembly of claim 1, wherein the endcap comprises an elastomeric material selected from a group consisting of thermoplastic polyurethan (TPU), thermoplastic elastomers (TPE), silicone-based polymers, flexible polyamides, and styrene block copolymers.

12. A tensegrity structure assembly comprising:a plurality of compression members, at least one of the plurality of compression members having an endcap engaged at a first end;a plurality of tension members, wherein at least one tension member of the plurality of tension members comprises:an outer portion having a first diameter and at least one portion with a second diameter that is larger than the first diameter;an internal filament traversing through the outer portion; andan endcap, or plurality thereof, coupled to at least one compression member and one tension member.

13. The tensegrity structure assembly of claim 12, wherein the endcap is disengaged from the at least one tension member by the at least one portion with a second diameter when tension in the tensegrity structure assembly exceeds a threshold.

14. The tensegrity structure assembly of claim 12, wherein at least one tension member is integrally formed with at least one endcap.

15. The tensegrity structure assembly of claim 12, wherein at least one tension member is coupled to at least one endcap by at least one of a press-fit connection, a mechanical interlocking mechanism, or a tension-retaining feature.

16. The tensegrity structure assembly of claim 12, wherein at least one tensile member is chemically bonded to at least one endcap.

17. A method of assembling a tensegrity structure assembly, the method comprising:positioning a tension member into an open channel of an endcap, the open channel defined by a space located between a gripping element and a body of an endcap;deforming the gripping element of the endcap during installation of the endcap for a temporary amount of time;allowing the gripping element to return to a baseline position; andsecuring the tension member in place.

18. The method of claim 17, further comprising disassembling a portion of the tensegrity structure assembly by:manually lifting the gripping element of an endcap;removing a tensile member from the open channel;reconfiguring the tensegrity structure assembly.

19. The method of claim 17, further comprising:inserting a slack portion of a tension member into the open channel;intertwining the tension member with the body of an endcap;rotating two elements in opposing directions to create tension within the tension member;securing the tension member in place.

20. The method of claim 17, further comprising anchoring a portion of the tension member to a portion of the endcap.

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