Hollow segmented linear actuator

Abstract

Disclosed are segmented linear actuator systems including four or more segmented members coupled via interlocking protrusions and arranged circumferentially forming a rigid member defining a hollow longitudinal enclosure.

Description

HOLLOW SEGMENTED LINE AR ACTUATORFIELD OF THE INVENTION

[0001] The present disclosure relates to systems for linear actuation and particularly to segmented linear actuator systems.BRIEF SUMMARY

[0002] According to a first aspect, there is provided a segmented linear actuator comprising: a plurality of segmented members, in an even number of four or more, arranged circumferentially about a central longitudinal axis of the segmented linear actuator forming a longitudinal enclosure, each segmented member comprising: a plurality of segments linked together and arranged to extend longitudinally, each segment comprising: protrusions extending from the segment for engaging with protrusions of segments of adjacent other segmented members.

[0003] In some embodiments, the segmented members adjacent one another are offset longitudinally by a distance being half a periodicity of the segments within each segmented member.

[0004] In some embodiments, the segments of the segmented member are linked such that they form a rigid elongate member when extended and are free to rotate relative to one another about axes perpendicular to the central longitudinal axis.

[0005] In some embodiments, each protrusion of each segmented member engages with two protrusions of adjacent other segmented members such that they interlock.

[0006] In some embodiments, the protrusions of the segments extend laterally from each segment of the segmented member.

[0007] In some embodiments, wherein the protrusions of the segments extend inwardly from each segment of the segmented member.

[0008] In some embodiments, each protrusion comprises a flared tab protrusion including: a flat mounting portion for mounting the flared tab protrusion to the segment; and a flat extending portion extending from the mounting portion at an angle perpendicular to the mounting portion, the mounting portion and the extending portion forming an L-shape, the extending portion flared so as to provide a wider longitudinal dimension for the extending portion distal of the segment, and to provide a narrower longitudinal dimension for the extending portion proximate the segment.

[0009] In some embodiments, the flared tab protrusions are flared at an angle such that once adjacent flared tab protrusions are interlocked, they restrain and guide the segmented members towards and against each other in response to external stress.

[0010] In some embodiments, the flared tab protrusions are flared at an angle substantially 15° from the perpendicular to the mounting portion.

[0011] According to another aspect, there is provided a segmented member for a segmented linear actuator comprising a plurality of segmented members, in an even number of four or more, arranged circumferentially about a longitudinal axis of the segmented linear actuator forming a longitudinal enclosure, for which the segmented members adjacent one another are offset longitudinally, the segmented member comprising: a plurality of segments linked together and arranged to extend longitudinally, each segment comprising: protrusions extending from the segment for engaging with protrusions of segments of adjacent other segmented members.

[0012] According to another aspect, there is provided a flared tab protrusion for a segmented linear actuator including a plurality of segmented members, in an even number of four or more, arranged circumferentially about a longitudinal axis of the segmented linear actuator forming a longitudinal enclosure, the segmented members adjacent one another offset longitudinally and including a plurality of segments linked together and arranged to extend longitudinally, each segment including said flared tab protrusions for engaging with flared tab protrusions of segments of adjacent other segmented members, the flared tab protrusion comprising: a flat mounting portion for mounting the flared tab protrusion to its segment; and a flat extending portion extending from the mounting portion at an angle perpendicular to the mounting portion, the mounting portion and the extending portion forming an L-shape; the extending portion flared so as to provide a wider longitudinal dimension for the extending portiondistal of the segment, and to provide a narrower longitudinal dimension for the extending portion proximate the segment.

[0013] The foregoing and additional aspects and embodiments of the present disclosure will be apparent to those of ordinary skill in the art in view of the detailed description of various embodiments and / or aspects, which is made with reference to the drawings, a brief description of which is provided next.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The foregoing and other advantages of the disclosure will become apparent upon reading the following detailed description and upon reference to the drawings.

[0015] FIG. 1 is a longitudinal view of an assembled segmented linear actuator with segmented members having interlocked protrusions extending laterally or circumferentially according to an embodiment.

[0016] FIG. 2 is lateral view of an assembled segmented linear actuator with segmented members having interlocked protrusions according to an embodiment.

[0017] FIG. 3 is detailed lateral view of an assembled segmented linear actuator with segmented members having interlocked protrusions according to an embodiment.

[0018] FIG. 4A is a side lateral view of a segmented member of the linear actuator according to an embodiment.

[0019] FIG. 4B is a front view of the segmented member of FIG. 4A.

[0020] FIG. 5 is a front lateral view of a linear actuator during assembly according to an embodiment.

[0021] FIG. 6 is a longitudinal view of an assembled segmented linear actuator with segmented members having interlocked protrusions extending inwardly according to an embodiment.

[0022] FIG. 7 is a longitudinal view of an assembled segmented linear actuator with segmented members having interlocked tab protrusions extending laterally according to an embodiment.

[0023] FIG. 8 is an oblique projected view of adjacent segmented members of an assembled segmented linear actuator with segmented members having interlocked tab protrusions according to an embodiment.

[0024] FIG. 9 is a detailed front view of interlocked tab protrusions of adjacent segmented members of an assembled segmented linear actuator according to an embodiment.

[0025] FIG. 10 is a detailed front view of interlocked tab protrusions of adjacent segmented members in the form of adjacent chains of an assembled segmented linear actuator according to an embodiment.

[0026] While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments or implementations have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of an invention as defined by the appended claims.DETAILED DESCRIPTION

[0027] Linear actuators have typically possessed limitations in that their extended lengths are constrained to a certain ratio of the collapsed length. For instance, a hydraulic cylinder's collapsed length can be no less than the length of one stage of one stroke. This is true of single stage as well as telescoping actuators. Scissor mechanisms have a different problem in that the extended mechanism is much less stable. The extended mechanism has as much material as the retracted mechanism, so the structural members must be designed with heavier material. Additionally, considering the envelope shape, the structure is made of open triangles which is very susceptible to deformation under axial loading in all three axes. When packaging constraints as well as mechanical stability are main drivers of design requirements, these limitations require other solutions.

[0028] Linear actuators comprised of interlocked segmented members are known, however, they typically comprise two interlocking segmented members which does not afford formation of any enclosure. Furthermore, known systems typically utilize custom formed linkedsegments with non-standard plates and or other interlocking forms, and in some cases non-standard means by which the members are driven for assembly.

[0029] Embodiments described hereinbelow provide for a segmented linear actuator which forms a rigid hollow columnar enclosure. The segmented linear actuator comprises an even number of four or more segmented members which are interlocked with circumferentially adjacent segmented members via lateral or inward protrusions. The enclosure so formed provides a conduit for any number of applications including mechanical, electrical, optical, fluid, etc. where a variable length longitudinal rigid and hollow structure is to be implemented. In some embodiments, interlocking tabs are provided as the protrusions, and in some embodiments, standard chains with affixed tabs are utilized as the segmented members, allowing for more standardized implementation with fewer custom requirements both for manufacture and assembly. Assembly of the segmented linear actuator is achieved via driving the four or more segmented members by appropriately configured motorized sprockets, belts, rollers, etc. causing them to mesh together, the protrusions interlocking, resulting in the segmented members forming the segmented linear actuator in the form of a rigid hollow column.

[0030] As the adjacent segments link, the tube extends, replicating the extension and stability of a similar tube constructed of similar material, but with the added benefit of extending from and retracting into a compact casing. The segmented member is capable of folding into a compact casing having dimensions smaller than the length of the segmented member when fully extended. The segmented linear actuator can be manufactured from different materials and at different sizes depending on the use case. Each segmented member is configured for rigidity in at least a longitudinal direction along its length. Due to the rigidity of the segmented members, the segmented linear actuator can lift, push, and pull objects vertically, horizontally, or diagonally. The segmented linear actuator can hold, push, and pull more weight for its size and composition than other linear actuators (e.g. linked actuators) and its strength and stability enables it to reach beyond what other technology reaches or where space is limited. As a smaller device, it could be used as hardware for opening and closing windows or doors, or for enabling a tool to be extended on a production line or into an enclosed space. As a larger tool, the segmented linear actuator can be used to lift, push, or pull heavy objects like tables or platforms. The interlocking protrusions of the segments improves resistance to buckling and reduces the need for a stabilizing framework.The segmented linear actuator can be used for collapsible robotic armatures such as lifts, jacks, or push-pull setups horizontally or vertically.

[0031] With reference to FIG. 1 a top view of an assembled segmented linear actuator 1000 will now be discussed.

[0032] The segmented linear actuator 1000 includes multiple segmented members 1100 arranged about a longitudinal axis 1001 of the segmented linear actuator 1000, forming a rigid self-supporting hollow member or rigid tube generally defining a circumference 1005 with an enclosure or elongated hollow 1010 therein. Generally, the terms “longitudinally”, “circumferentially”, “laterally”, and “radially” (“outwardly” and “inwardly”) herein are to be understood in view of the assembled segmented linear actuator 1000 and its longitudinal axis 1001 and circumference 1005. In the context specifically of each segmented member, references to “forward” and “rearward” are indicative of directions respectively away from and toward the longitudinal axis, and “laterally” generally designates directions at right angles to “forward” and “rearward”, and accordingly any reference to a “front”, “rear”, or “side” associated with the segmented members or their segments are defined accordingly.

[0033] Each segmented member 1100 includes a multiplicity of segments 1110 stacked and linked in a longitudinal direction parallel to the longitudinal axis 1001. On each side portion of each segment 1110, disposed generally laterally or circumferentially, are protrusions 1115L 1115R extending generally laterally or circumferentially away from segment 1110. The protrusions 1115 of a segment 1110 overlap and engage with adjacent protrusions 1115AR 1115BL of adjacent segments 1110A 1110B, situated above and below in the longitudinal direction such that the segments 1110 are interlocked with adjacent segments 1110A 1110B of adjacent segmented members 1100A 1100B, thereby interlocking adjacent segmented members 1100 to each other. The protrusions 1115 may be separate members or elements affixed and attached to the segments 1110 or portions integral with and formed from the segment 1110 itself.

[0034] The protrusions 1115L 1115R of the segmented member 1100 engage the adjacent segments 1110A 1110B and / or their protrusions 1115AR 1115BL, while the protrusions 1115AR 1115BL of the adjacent segmented members 1100A 1100B engage the segment 1110 and / or its protrusions 1115L 1115R, so as to prevent relative movement between the segmented member 1100 and the adjacent segmented members 1100 A HOB laterally, circumferentially, outwardly, and inwardly, as well as preventing relative rotational movement in a plane perpendicular to thelongitudinal axis 1001. Likewise, for every other segmented member of the segmented linear actuator 1000, relative movement between segments adjacent to one another is prevented by engagement between their protrusions and the segments themselves. In some embodiments, as described below, the protrusions comprise flared tabs which extend laterally and interlock with adjacent segment’s tabs, while in other embodiments, the protrusions include ball and cup / socket arrangements, interlocking ball-ball arrangements, or interlocking prism-prism arrangements (similar to the tab embodiment described below but with wider extruded forms rather than relatively thin metal) or other interlocking mechanism. Each protrusion is arranged to slide into place at an angle and lock in place once aligned and fit together as will be more apparent in the discussion below.

[0035] Referring also now to FIG. 2, each segmented member 1100 includes linking mechanisms which couple the segments 1110 of the segmented member 1100 to each other. Although represented as separate linking elements 1150 between the segments 1110 of each segmented member 1100, the linking mechanism may be comprised in the segments 1110 themselves providing direct linking of segments to their longitudinally adjacent segments 1110. In either case, as is described below in connection with FIG. 4, the segments 1110 and linking elements 1150 are coupled such that the segments may be rotated about axes which are perpendicular to the longitudinal axis and substantially tangential to the circumference 1005.

[0036] Each segmented member 1100 is offset along the longitudinal axis (the y-direction in FIG. 2) relative the adjacent segmented members 1100 A 1100B such that protrusions of the segmented member 1100 and those of its adjacent segmented members 1100 A 1100B alternatingly overlap and engage with one another. In some embodiments, adjacent segmented members 1100 are offset longitudinally by a distance of half the periodic length of the arrangement of segments 1110 within the segmented member 1100. Each protrusion 1115AR of the adjacent segmented member 1100A to one side is engaged above and below by protrusions 1115L of the segmented member 1100 and vice versa, while each protrusion 1115BL of the adjacent segmented member 1100B to the other side is engaged above and below by protrusions 1115R of the segmented member 1100 and vice versa. Likewise, for each other segmented member of the segmented linear actuator 1000, a segmented member’s protrusions are engaged above and below by the adjacent segmented member’s protrusions. With reference also to FIG. 3, a detailed view WOOD of the segmented linear actuator 1000 shows areas of engagement 200 between longitudinally disposedportions of the protrusions, for example portions of protrusions 1115AR of adjacent segmented member 1100A engaging with portions of protrusions 1115L of the segmented member 1100.

[0037] Due to this overlapping and alternating arrangement of the protrusions of adjacent segmented members, the portions of the protrusions disposed longitudinally which engage one another prevent the adjacent segmented members from relative movement in the longitudinal direction. To prevent relative rotation of the segmented members about axes parallel to the longitudinal axis, and to prevent lateral sliding of adjacent members away from the segmented member 1100, the shape and surfaces of the protrusions which engage protrusions of adjacent segmented members are formed such that they tend to retain and restrict said outward lateral movement and preferably are shaped so as to guide adjacent segmented members 1100 A 1100B towards the segmented member 1100 under various applied stresses.

[0038] With reference to FIG. 4, each segmented member 1100 is rigid longitudinally along its length when straightened which is the case when assembled along a longitudinal axis of the assembled segmented linear actuator 1000, for example, in the straightened region 1104 of the segmented member 1100 depicted in FIG. 4. This rigidity in combination with the prevention of relative movement of the segmented members 1100 once interlocked, prevents buckling of the segmented linear actuator 1000 once assembled.

[0039] Absent engagement, the segments 1110 via the link elements 1150 or direct linking mechanism, are free to rotate about axes perpendicular to the longitudinal axis of the segmented linear actuator 1000. In this way multiple segmented members 1100 may be drawn up from a horizontal or coiled-up or otherwise disassembled storage configuration 1102 into the assembled segmented linear actuator 1000 by way of a motorized assembly apparatus (not shown), which as indicated generally in FIG. 5, conveys the segmented members together such that they interlock to form the segmented linear actuator 1000. As was briefly noted above, assembly of the segmented members 1100 is such that the segments 1110 are simultaneously rotated while brought closer together and into engagement, via protrusions 1115, with adjacent segmented members 1100. The protrusions are formed so as to facilitate assembly while providing the interlocking once assembled.

[0040] With reference also to FIG. 6, although the protrusions of FIGs. 1-5 have been shown as extending laterally relative to each segment, they may be attached or formed on the inwardly disposed portions of the segment 1110 and extend inwardly, such as protrusions 3115L3115R of the segmented member 1100 of FIG. 6. Adjacent segments 1110A 1110B of adjacent segmented members 1100 A 1100B possess coordinate interlocking protrusions 3115AR 3115BL which also are inwardly extending and located. In general, the embodiments such as that depicted in FIG. 6 are assembled and function similarly to the other embodiments described herein, albeit with reduced space in the interior elongated hollow 1010.

[0041] Referring also to FIGs. 7 and 8, in some embodiments, the protrusions comprise L- shaped tabs 4115, affixed to and with portions extending from the segments 1110 of the segmented member 1100 at 90° to a direction the segmented member 1100 is offset from the longitudinal axis 1001, i.e. affixed to the sides of extending laterally with respect to the segment 1110. Extending portions 420 of the tabs 4115 extend from the segments 1110 and overlap and engage one another. For example, extended portions 420L 420R of tabs 4115L 4115R of a segmented member 1100 engage extending portions 420AR of tabs 4115 AR of adjacent segmented member 1100A and engage extending portions 420BL of tabs 4115BL of adjacent segmented member 1100B. The rigid L-shapes of the tabs 4115 of adjacent segmented members 1100 assists in torsional rigidity when fully engaged and interlocked with each other. As illustrated in FIG. 7 and in the oblique view 1000E of the segmented linear actuator of FIG. 8, each tab 4115 comprises a mounting portion 460 attached to the segment 1110 supporting the extending portion 420, and in some embodiments also includes an arcuate connecting portion 440 which connects the two. In some embodiments, mounting portions 460 are extended longitudinally in the form of wings 462 which further provide guiding surfaces to help guide the extending portions 42 to engage and interlock during assembly. The extending portions 420 of the tabs of the segments 1110, in addition to engaging each other, also engage mounting portions 460 of the tabs of adjacent segments 1110A, primarily the wings 462 of the mounting portions 460, and in some embodiments also engage some portion of the arcuate connecting portion 440 at regions 200. For example, rearward surfaces of the extending portions 420L of the tabs 4115L of the segments 1110 engage lateral outer surfaces of the wings 462AR of the mounting portions 460AR of the adjacent segments 1110A, and rearward surfaces of the extending portions 420AR of the tabs 4115 AR of the adjacent segments 1110A engage lateral outer surfaces of the wings 462L of the mounting portions 460L of the segments 1110. In some embodiments the tabs 4115 of the protrusions do not include mounting portions 460 or connecting arcuate portions 440 but are formed to extend directly from thesegments 1110. In some embodiments, the tabs 4115 are integral with and formed from the segments 1110 rather than being affixed to them.

[0042] With reference also to FIG. 9, the tabs 4115 are formed such that the extending portion 420 of each tab 4115 is flared, i.e. has a wider longitudinal dimension for portions farther away from the segment 1110, and is longitudinally narrower closer to the segment 1110. As shown in the detailed front lateral view lOOOF of the segmented linear actuator 1000 of FIG. 9, in some embodiments the extending portion 420 of the tab 4115 is flared outward at about a 15° angle relative to a plane perpendicular to the longitudinal axis 1001. The flared tabs 4115 allow for ease of assembly while tending to retain and restrict outward lateral movement and guide adjacent segments 1110 1110A towards each other under various applied stresses once the segmented linear actuator 1000 is assembled. For example, as shown in FIG. 9, segments 1110 are prevented from moving in a positive z-direction (out of the page in FIG. 9) and the positive x-direction relative to the adjacent segment 1110A due to the flared tabs 4115L of the segments 1110 being engaged with flared tabs of the adjacent segment 1110A at regions 200 which is where the flared tab extending portions 420L and the adjacent flared tab extending portions 420AR are narrowest in the longitudinal direction. Likewise, adjacent segments 1110A are prevented from moving in a negative z-direction (into the page in FIG. 9) and the negative x-direction relative to the segment 1110 due to the flared tabs 4115L of the segments 1110 being engaged with flared tabs of the adjacent segment 1110A at regions 200 which is where the flared tab extending portions 420L and the adjacent flared tab extending portions 420AR are narrowest in the longitudinal direction.

[0043] In some embodiments each tab 4115 is not flared but instead includes notches in the engagement regions 200, the notches defining a narrower longitudinal width near to the segment 1110 of which it is a part, than a longitudinal width of the remaining extending portion 420. Each notch formed in the edge of the extending portions 420 of the tabs 4115 is wide enough to accept a thickness of the extending portions 420AR of tabs 4115 AR with which it engages. In some embodiments, the notch is narrow enough to provide a tight fitting of tabs when the segmented members are interlocked.

[0044] As shown in the detailed front lateral view 1000G of the segmented linear actuator 1000 of FIG. 10, in some embodiments, the segmented members 1100 are each comprised of a chain, and the protrusions 1115 comprise tabs 4115 attached to the outer link plates of the chain on either side. The mounting portions 460 of the tabs 4115 are formed to fit around the pins of thechain and provide a surface including wings 462 for engagement against coordinate extending portions 420 of tabs of segments of adjacent segmented members. As indicated in FIG. 10, the natural rotation of the chain links relative to one another about the pins is transformed into a squeezing or compressive force on each tab 4115 by the tabs of the adjacent segments from both directions along the longitudinal axis. This clamping force on each tab 4115 helps to prevent buckling of the segmented linear actuator 1000.

[0045] In some specific embodiments, analogous with the broader embodiments described above, the segmented linear actuator 1000 is comprised of four lengths of chain positioned such that they are 90° from the adjacent length of chain and are connected by flared tabs which capture and contain adjacent tabs at 90°. When the chains are driven by motorized sprockets, they mesh together at right angles to form a rigid hollow column. As the chains link, the tube extends, replicating the extension and stability of a similar tube constructed of similar material, but with the added benefit of extending from and retracting into a compact casing. The chain actuator can be manufactured from different materials and at different sizes depending on the use case. Because of the rigidity of the linked chains, the actuator can lift, push and pull objects vertically, horizontally or diagonally. The actuator can hold, push and pull more weight for its size and composition than other linear chain actuators and its strength and stability enables it to reach beyond what other technology reaches or where space is limited. As a smaller device, it could be used as hardware for opening and closing windows or doors, or for enabling a tool to be extended on a production line or into an enclosed space. As a larger tool, the actuator can be used to lift, push or pull heavy objects like tables or platforms. The interlocking chain improves resistance to buckling and reduces the need for a stabilizing framework. The actuator can be used for collapsible robotic armatures like lifts, jacks, or push-pull setups horizontally or vertically. Use of any one of the standard or common chain types reduces manufacturing costs and assembly time for each segmented member, as well as reducing the same in association with creation of the driving apparatuses which can be supplied with standardized driving sprockets and the like. In some embodiments the tabs are created for convenient fitment to standardized types and sizes of chains and in others, sold in a kit for the creation of segmented members and segmented linear actuators as described herein.

[0046] Although the segmented linear actuator 1000 has been described and illustrated as having four segmented members 1100 it should be understood that the segmented linear actuator 1000 may include any even number of segmented members greater than four.

[0047] Although the segmented linear actuator 1000 has been described and illustrated as having identical segmented members 1100 it should be understood that the segmented linear actuator 1000 may include segmented members 1100 of different lateral widths leading to an oblong arrangement in the plane perpendicular to the longitudinal axis, or in the case of four segmented members 1100, a rectangular rather than a square arrangement as depicted in FIGs. 1, 6, and 7.

[0048] Although the segmented members 1100 described and illustrated above include linked segments 1110, in some embodiments the segmented members 1100 are segmented only in that they possess protrusions at regular intervals defining the segments of the members 1100. In such embodiments, the members 1100 themselves comprise a continuous flexible member such as a ribbon, tape, or other relatively thin rollable member such as rollable spring metal having a laterally concave metal blade (e.g. similar to that used for a tape measure), rather than segments coupled to one another. In some embodiments rather than protrusions or tabs being affixed to the metal tape, the metal tape edge profile itself is cut, or stamped to provide interlocking protrusions, which are capable of being much more compact and have a more favorable ratio between collapsed and retracted lengths.

[0049] While particular implementations and applications of the present disclosure have been illustrated and described, it is to be understood that the present disclosure is not limited to the precise construction and compositions disclosed herein and that various modifications, changes, and variations can be apparent from the foregoing descriptions without departing from the spirit and scope of an invention as defined in the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A segmented linear actuator comprising: a plurality of segmented members, in an even number of four or more, arranged circumferentially about a central longitudinal axis of the segmented linear actuator forming a longitudinal enclosure, each segmented member comprising: a plurality of segments linked together and arranged to extend longitudinally, each segment comprising: protrusions extending from the segment for engaging with protrusions of segments of adjacent other segmented members.

2. The segmented linear actuator of claim 1, wherein the segmented members adjacent one another are offset longitudinally by a distance being half a periodicity of the segments within each segmented member.

3. The segmented linear actuator of claim 1, wherein the segments of the segmented member are linked such that they form a rigid elongate member when extended and are free to rotate relative to one another about axes perpendicular to the central longitudinal axis.

4. The segmented linear actuator of claim 1, wherein each protrusion of each segmented member engages with two protrusions of adjacent other segmented members such that they interlock.

5. The segmented linear actuator of claim 4, wherein the protrusions of the segments extend laterally from each segment of the segmented member.

6. The segmented linear actuator of claim 4, wherein the protrusions of the segments extend inwardly from each segment of the segmented member.

7. The segmented linear actuator of claim 4, wherein each protrusion comprises a flared tab protrusion including: a flat mounting portion for mounting the flared tab protrusion to the segment; and a flat extending portion extending from the mounting portion at an angle perpendicular to the mounting portion, the mounting portion and the extending portion forming an L-shape, the extending portion flared so as to provide a wider longitudinal dimension for the extending portion distal of the segment, and to provide a narrower longitudinal dimension for the extending portion proximate the segment.

8. The segmented linear actuator of claim 7, wherein the flared tab protrusions are flared at an angle such that once adjacent flared tab protrusions are interlocked, they restrain and guide the segmented members towards and against each other in response to external stress.

9. The segmented linear actuator of claim 8, wherein the flared tab protrusions are flared at an angle substantially 15° from the perpendicular to the mounting portion.

10. A segmented member for a segmented linear actuator comprising a plurality of segmented members, in an even number of four or more, arranged circumferentially about a longitudinal axis of the segmented linear actuator forming a longitudinal enclosure, for which the segmented members adjacent one another are offset longitudinally, the segmented member comprising: a plurality of segments linked together and arranged to extend longitudinally, each segment comprising: protrusions extending from the segment for engaging with protrusions of segments of adjacent other segmented members.

11. The segmented member of claim 10, wherein the segments of the segmented member are linked such that they form a rigid elongate member when extended and are free to rotate relative to one another about axes perpendicular to the central longitudinal axis.

12. The segmented member of claim 10, wherein each protrusion of each segmented member engages with two protrusions of adjacent other segmented members such that they interlock.

13. The segmented member of claim 12, wherein the protrusions of the segments extend laterally from each segment of the segmented member.

14. The segmented member of claim 12, wherein the protrusions of the segments extend inwardly from each segment of the segmented member.

15. The segmented member of claim 12, wherein each protrusion comprises a flared tab protrusion including: a flat mounting portion for mounting the flared tab protrusion to the segment; and a flat extending portion extending from the mounting portion at an angle which is perpendicular to the mounting portion, the mounting portion and the extending portion forming an L-shape, the extending portion flared so as to provide a wider longitudinal dimension for the extending portion distal of the segment, and to provide a narrower longitudinal dimension for the extending portion proximate the segment.

16. The segmented member of claim 15, wherein the flared tab protrusions are flared at an angle such that once adjacent flared tab protrusions are interlocked, they restrain and guide the segmented members towards and against each other in response to external stress.

17. The segmented member of claim 16, wherein the flared tab protrusions are flared at an angle substantially 15° from the perpendicular to the mounting portion.

18. A flared tab protrusion for a segmented linear actuator including a plurality of segmented members, in an even number of four or more, arranged circumferentially about a longitudinal axis of the segmented linear actuator forming a longitudinal enclosure, the segmented members adjacent one another offset longitudinally and including a plurality of segments linked together and arranged to extend longitudinally, each segment including said flared tab protrusions for engaging with flared tab protrusions of segments of adjacent other segmented members, the flared tab protrusion comprising: a flat mounting portion for mounting the flared tab protrusion to its segment; and a flat extending portion extending from the mounting portion at an angle perpendicular to the mounting portion, the mounting portion and the extending portion forming an L-shape; the extending portion flared so as to provide a wider longitudinal dimension for the extending portion distal of the segment, and to provide a narrower longitudinal dimension for the extending portion proximate the segment.

19. The flared tab protrusion of claim 18, wherein the flared tab protrusion is flared at an angle such that once adjacent flared tab protrusions of said segmented linear actuator are interlocked, they restrain and guide the segmented members towards and against each other in response to external stress.

20. The flared tab protrusion of claim 19, wherein the flared tab protrusion is flared at an angle substantially 15° from the perpendicular to the mounting portion.

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