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Title:
IMPROVED EXOSKELETON SYSTEM FOR LOAD CARRYING
Document Type and Number:
WIPO Patent Application WO/2018/191777
Kind Code:
A1
Abstract:
The present invention relates to exoskeleton systems and more particularly to lower extremity exoskeleton systems and components thereof. Such components include an input assembly and an output assembly. The input assembly includes an input housing, an upper load carriage, and a lower load carriage. The upper load carriage and the lower load carriage are located within the input housing. The upper load carriage is arranged in use to receive an applied load and to transfer at least a first part of that applied load as a transfer load to the lower load carriage. The lower load carriage is arranged to apply the transfer load to an inner cable of at least one Bowden cable. The output assembly is arranged to transfer a load from a Bowden cable to the ground. The output assembly includes a leg brace arranged for connection to the leg of a user, a cable transfer assembly arranged for connection to the leg brace and to the Bowden cable, a boot brace, and a pivot joint pivotally connecting the boot brace to the cable transfer assembly.

Inventors:
CHAPMAN THOMAS (AU)
TAYLOR KYNAN (AU)
HUNT NATHANAEL (AU)
GOODWIN BENJAMIN (AU)
CHRISTMAS ELIZABETH (AU)
KRIGSMAN MARCUS (AU)
MORRISH CHRISTOPHER (AU)
Application Number:
PCT/AU2018/050345
Publication Date:
October 25, 2018
Filing Date:
April 18, 2018
Export Citation:
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Assignee:
COMMONWEALTH AUSTRALIA (AU)
International Classes:
A61H3/00; A45F3/00; A61F2/00; A63B25/00
Domestic Patent References:
WO2015157803A12015-10-22
WO2016109695A12016-07-07
WO2013086035A12013-06-13
Foreign References:
US20150173993A12015-06-25
CN106491318A2017-03-15
Attorney, Agent or Firm:
PHILLIPS ORMONDE FITZPATRICK (AU)
Download PDF:
Claims:
Claims

1 . An input assembly for an exoskeleton system, said input assembly including an input housing, an upper load carriage and a lower load carriage located within the input housing, said upper load carriage arranged in use to receive an applied load and to transfer at least a first part of that applied load as a transfer load to the lower load carriage, and said lower load carriage arranged to apply said transfer load to an inner cable of at least one Bowden cable.

2. An input assembly according to claim 1 arranged to be mounted to or formed with a frame arranged for attachment to a user.

3. An input assembly according to claim 1 or claim 2 wherein the inner cable of the at least one Bowden cable is arranged to transfer the load to an output assembly which in turn is configured to transfer the transfer load to the ground.

4. An input assembly according to claim 3 wherein the output assembly includes a leg brace and a boot brace, the boot brace arranged for connection to a part of a user's boot.

5. An input assembly according to claim 4 wherein the boot brace is arranged to connect to a sole of the user's boot.

6. An input assembly according to any one of the preceding claims wherein the input assembly includes means for securing an outer sheath of the at least one Bowden cable within the input housing to prevent movement of the outer sheath at that securing point when the transfer load is applied to the inner cable thereof.

7. An input assembly according to claim 6 wherein the securing means includes a clamp or saddle arranged to engage with the input housing and to locate the outer sheath of the Bowden cable securely therebetween to prevent movement of the outer sheath.

8. An input assembly according to any one of the preceding claims arranged to transfer the transfer load to two Bowden cables or to four Bowden cables.

9. An input assembly according to any one of the preceding claims further including means for adjusting the amount of the applied load which is transferred as the transfer load to the lower load carriage.

10. An input assembly according to claim 9 wherein the adjusting means includes means for limiting the travel of the upper load carriage against the bias of at least one biasing means located between the upper load carriage and the lower load carriage.

1 1 . An input assembly according to claim 10 wherein the travel of the upper load carriage is limited by an end of a rod or other member contacting with a bearing surface associated with the input housing.

12. An input assembly according to claim 1 1 wherein the rod or other member is connected to the upper load carriage so that a length of the rod or other member extending below the upper load carriage is adjustable.

13. An input assembly according to any one of the preceding claims further

includes a first member and a second member that extend substantially parallel to one another within the input housing, the upper and lower load carriages being arranged for movement along said members and are separated by at least one biasing means.

14. An output assembly for an exoskeleton system arranged to transfer a load from a Bowden cable to the ground, the output assembly including a leg brace arranged for connection to the leg of a user, a cable transfer assembly arranged for connection to the leg brace and to the Bowden cable, a boot brace, and a pivot joint pivotally connecting the boot brace to the cable transfer assembly.

15. An output assembly according to claim 14 wherein the cable transfer assembly includes means for securing an outer sheath of the Bowden cable at a lower end thereof relative to leg brace and means for aligning the inner cable of the Bowden cable so that the load applied to the inner cable is transferred to the boot brace.

16. An output assembly according to claim 14 or claim 15 further including means for opposing the load transferred to the boot brace.

17. An output assembly according to claim 16 wherein the opposing means

includes an ankle or foot brace worn or the like worn by the user.

18. An output assembly according to claim 15 wherein the boot brace is arranged to transfer the applied load to the user's boot.

19. An output assembly according to claim 18 wherein the boot brace is arranged to transfer the applied load to the user's boot via the sole of the user's boot.

20. An exoskeleton system including an input assembly according to any one of claims 1 to 13 and an output assembly according to any one of claims 14 to 19.

21 . An exoskeleton system according to claim 20 wherein the input assembly is mounted on a torso frame.

22. An exoskeleton system according to claim 21 further including a belt and thigh brace assembly arranged for connection to the user.

23. An exoskeleton system according to claim 22 arranged to enable variation of the length of Bowden cable extending between the user's hip and knee.

24. An exoskeleton system according to claim 22 arranged to enable variation of the length of Bowden cable extending between the user's knee and the

Bowden cable's connection to the output assembly.

Description:
Improved Exoskeleton System for Load Carrying

Technical Field

[0001 ] The present invention relates to exoskeletons and more particularly to lower extremity exoskeleton systems designed to facilitate the user carrying heavy loads for extended periods while mitigating fatigue and the risk of injury.

Related Application

[0002] This application is related to Australian provisional patent application 2017901400 filed on 18 April 2017. The contents of which provisional patent application are incorporated fully herein by way of this reference.

Background of Invention

[0001 ] Many different forms of exoskeletons have been developed to date to augment the strength of the user, augment the endurance of the user, facilitate locomotion of the user over differing terrains or to support a payload being carried by the user.

[0002] The problems with and limitations of such previously developed

exoskeletons were well discussed in the present applicant's earlier international patent application PCT/AU2015/000225. That international patent application was published as WO2015/157803 and disclosed an exoskeleton system for load carrying. The contents of WO2015/157803 are incorporated herein by reference.

[0003] The exoskeleton system described in WO2015/157803 includes a load carriage arrangement for carrying an applied load and at least one non-rigid member arranged to transfer at least a first part of the applied load carried by the load carriage arrangement to the ground bypassing the user's musculoskeletal system. The at least one non-rigid member adopted in a described embodiment of the invention took the form of a Bowden cable. Such an exoskeleton system provided considerable advantages over the prior art. However, the present invention seeks to provide an exoskeleton system for load carrying which is further improved and/or related componentry.

[0004] The discussion of the background to the invention herein is included to explain the context of the invention. This is not to be taken as an admission that any of the material referred to was published, known or part of the common general knowledge as at the priority date of this application.

Summary of Invention

[0005] According to the present invention, there is provided an input assembly for an exoskeleton system, said input assembly including an input housing, an upper load carriage and a lower load carriage located within the input housing, said upper load carriage arranged in use to receive an applied load and to transfer at least a first part of that applied load as a transfer load to the lower load carriage, and said lower load carriage arranged to apply said transfer load to an inner cable of at least one Bowden cable.

[0006] In accordance with an embodiment of the invention, the input assembly is arranged to be mounted to or formed with a frame. The frame is arranged to be attached to a user, preferably using a harness arrangement. The frame will be hereafter identified as a torso frame.

[0007] In accordance with one embodiment of the invention, the inner cable of the at least one Bowden cable is arranged to transfer the load to an output assembly which in turn is configured to transfer the transfer load to the ground. The output assembly is preferably arranged to be attached to the leg of the user. The output assembly preferably adopts the form of a leg brace which preferably includes a boot brace which is arranged to be connected to a part of the user's boot. Preferably, the boot brace connects to the sole of the user's boot. The transfer load is preferably transferred to the ground bypassing the user's musculoskeletal system. By transferring the transfer load to the ground whilst bypassing the user's

musculoskeletal system, the system is expected to provide advantages to the user which may include less strain on their musculoskeletal system, lower levels of injury as a result of carrying high loads, and improved endurance throughout load carrying tasks. Different users are expected to experience different results dependent on their own body type, strength and level of fitness.

[0008] Preferably, the input assembly includes means for securing an outer sheath of the at least one Bowden cable within or adjacent to the input housing to prevent movement of the outer sheath at that securing point when the transfer load is applied to the inner cable thereof. The securing means may include a clamp or saddle arranged to engage with the input housing and to locate the outer sheath(s) of the Bowden cable(s) securely therebetween to prevent movement of the outer sheath(s).

[0009] Preferably, the input assembly includes means for securing the outer sheaths of two Bowden cables or alternatively the outer sheaths of four Bowden cables or to other multiple cable arrangements.

[0010] Preferably, the input assembly includes means for adjusting the amount of the applied load which is transferred as the transfer load to the lower load carriage. This thus enables the user to adjust and accordingly limit the amount of load applied to the user's body (i.e. applied to the user's musculoskeletal system) via the torso frame and harness arrangement that is attached to the user.

[001 1 ] In accordance with an embodiment of the invention, the input assembly further includes a first rod and a second rod that extend substantially parallel to one another within the input housing. The upper and lower load carriages are arranged for movement along said rods and are separated by at least one biasing means. The upper and lower load carriages, rods and biasing means are arranged so that when the applied load acts on the upper load carriage, the upper load carriage travels along the rods against the bias of the spring so as to apply the transfer load to the lower load carriage. The lower load carriage is arranged to apply the transfer load to the inner cable of the at least one Bowden cable.

[0012] In accordance with an embodiment of the invention, the adjusting means includes means for limiting the travel of the upper load carriage against the bias of the spring. Preferably, the travel of the upper load carriage is limited by an end of a rod or other member contacting with a bearing surface associated with the input housing. The rod or other member is preferably connected to the upper load carriage so that a length of the rod or other member extending below the upper load carriage (i.e. in the direction of the lower load carriage) can be adjusted. When the end of the rod contacts the bearing surface, further movement of the upper load carriage against the bias of the spring is prevented and thus any load beyond that already transferred via the spring to the second load carriage will be transferred to the bearing surface.

When the input assembly is mounted on the torso frame and is secured to a user, the load applied to the bearing surface will be transferred to the user, typically to the user's shoulders, via the user's contact with the torso frame. When the harness arrangement connecting the torso frame to the user includes a hip or waist belt arrangement, load will also be transferred to the user's torso. In this manner it is possible to adjust the amount of the applied load that is transferred to the ground as opposed to being transferred to and through the musculoskeletal system of the user.

[0013] The invention further provides an output assembly for an exoskeleton system arranged to transfer a load from a Bowden cable to the ground, the output assembly including a leg brace arranged in use for connection to the leg of a user, a cable load transfer assembly arranged for connection to the leg brace and to the Bowden cable, a boot brace, and a pivot joint pivotally connecting the boot brace to the cable load transfer assembly. The output assembly is configured to transfer the load applied to the Bowden cable to the ground, via the user's boot.

[0014] The cable load transfer assembly includes means for securing, for example by means of a sliding connection, an outer sheath of the Bowden cable at a lower end thereof relative to leg brace and means for securing the inner cable of the Bowden cable so that the load applied to the inner cable can be transferred to the boot brace. Means for opposing the load transferred to the boot brace is preferably also provided in the form of an ankle or foot brace worn by the user. The ankle or foot brace being arranged for connection to the leg brace preferably by at least one strap or other attachment. It is envisaged that the ankle or foot brace may include a bespoke sock or an innersole arrangement.

[0015] In accordance with an embodiment of the invention, the leg brace and ankle/foot brace are connected together in a manner which allows the leg brace to move, for example slide, independently of the ankle/foot brace to facilitate the transfer of the load applied to the inner cable of the Bowden cable to the ground. [0016] The boot brace is arranged to transfer the transfer load to the user's boot, preferably via the sole of the user's boot. The boot brace is preferably configured to limit any impact of movement of the user's foot and to provide smooth rotational motion of the user's ankle.

[0017] In accordance with one embodiment, the boot brace is configured to follow the external contour of the rear of the user's boot and is arranged to attach to the sole of the user's boot via screws connected to threaded inserts located within the sole.

[0018] Preferably, the components of the output assembly are designed to maximise strength and stiffness whilst minimising weight.

Brief Description of Drawings

[0019] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0020] Figure 1 is a view from the rear side of a user wearing an exoskeleton system, excluding a pack, according to an embodiment of the invention;

[0021 ] Figure 2 is a rear isometric view of a torso frame fitted with an input assembly according to an embodiment of the invention. Only an upper part of each Bowden cable is depicted;

[0022] Figure 3 is a rear isometric view of the input assembly shown in Figure 2 with cover removed and provisioned with four Bowden cables (only partly shown);

[0023] Figure 4 is a rear isometric view an input assembly according to an embodiment of the invention with cover removed and provisioned with two Bowden cables (only partly shown);

[0024] Figure 5 illustrates the load adjustment feature of the input assembly shown in Figure 2;

[0025] Figure 6 is another rear isometric view of the input assembly shown in Figure 3 and additionally showing the four Bowden cables connected to

compensators. The lower carriage of the input assembly has been removed for clarity; [0026] Figure 7 is an underside view of the lower carriage of the input assembly as shown in Figure 3 and showing the positioning of the four load cables;

[0027] Figure 8 is an underside view of the lower carriage of the input assembly as shown in Figure 4 and showing the positioning of the two load cables;

[0028] Figure 9 illustrates an input assembly according to an embodiment of the invention;

[0029] Figure 10 is a front isometric view showing an upper part of a pack frame fitted with a pack load input mount. The load input mount is shown ready for engagement to the upper carriage of the input assembly (not shown);

[0030] Figure 1 1 is a front side isometric view of the output assembly shown in Figure 1 ;

[0031 ] Figure 12 better illustrates the attachment of the Bowden cable to the output assembly;

[0032] Figure 13 is side view of an output assembly according to an embodiment of the invention connected to a boot of a user;

[0033] Figure 14 is a rear view of an alternative torso frame;

[0034] Figure 15 is a rear view showing the torso frame of Figure 14 connected to a harness arrangement and a belt and thigh brace assembly;

[0035] Figure 16 is a view from the rear side of a user wearing an exoskeleton system, excluding a pack, including the componentry shown in Figure 15;

[0036] Figure 17 illustrates an alternative form of lower leg brace;

[0037] Figures 18A and 18A illustrates a torso frame with connected belt and thigh brace assembly according to an embodiment of the invention (cable restraints not shown);

[0038] Figures 19A and 19B illustrate thigh braces with adjustable cable connectors; [0039] Figure 20 illustrates an adjustable cable connector for use on a belt assembly; and

[0040] Figure 21 illustrates a mechanism for user adjustment of the load transferred to their musculoskeletal system.

Detailed Description

[0041 ] Figure 1 illustrates a user wearing an exoskeleton system 10 according to an embodiment of the invention. The exoskeleton system 10 includes an input assembly 100, an output assembly 200 and at least one non-rigid member 300 arranged to transfer at least a first part of the load applied to the input assembly 100 to the output assembly 200 and then to the ground, bypassing the user's

musculoskeletal system. As illustrated and described hereinafter, the non-rigid members 300 adopt the form of push/pull control cables which are commonly referred to as Bowden cables. Such cables 300 include an outer sheath 302 and an inner cable 304. In accordance with some embodiments, transfer of load is achieved using two such Bowden cables 300 (one per leg of the user), whilst in other embodiments, four such Bowden cables 300 (two per leg of the user) are used. It is envisaged that other multiples of Bowden cables 300 could be adopted.

[0042] Throughout this document, terms such as "vertical", "upwardly" and "downwardly" and the like will be used. It should be understood that such terms are used with reference to the system of an embodiment of the invention as orientated when worn by a user who is standing generally upright. Reference is also made herein to the user's "boot" and to the "boot" brace. It should be understood that it is intended that the term "boot" encompass any suitable item of footwear worn by a user.

[0043] In Figure 1 , the exoskeleton system 10 incorporates four Bowden cables 300 and the system 10 is shown without any load carrying arrangement (i.e. pack or other load) attached thereto. As will be appreciated, many different load carrying arrangements may be configured to be secured to a system according to an embodiment of the present invention. However, in the following description, the load carrying arrangement will be described as a pack of the type typically worn by military personnel. More particularly, and as best illustrated by way of Figure 10, the load carrying arrangement is in the form of a pack (not shown) that includes a pack frame 20. The illustrated pack frame 20 is known in the industry as an ONE299 adjustable pack frame. However, the invention is not limited to use with such pack frames, and indeed a formal pack frame may not be required. The pack frame 20 as shown in Figure 10 has an input mount 22 mounted thereon.

[0044] As shown in Figure 1 , the input assembly 100 is mounted on a torso frame 350 which is secured to the user by a harness arrangement 400. Such harness arrangements 400 are well known in the art and any suitable arrangement may be adopted for use with an embodiment of the invention.

[0045] It will be appreciated that in use, the frame 350 connected to the user by the harness arrangement 400 (i.e. the torso frame 350) and the frame 20 of the pack (or other load to be carried) are preferably configured to interface so as to establish an arrangement that can be readily carried by the user. Preferably, in doing so, the torso frame 350 and pack frame 20 provide to the user the impression that they are carrying a one piece unit such as a conventional back pack. However, the interface between the torso frame 350 and the pack frame 20 or pack must be such to allow the pack to slide freely in the vertical position and not "hook up" on the torso frame 350 or harness arrangement 400 when load is applied. If the pack frame 20 was to hook or catch on the torso frame 350 or harness arrangement 400, load intended to be transferred to the ground may be inadvertently returned to the user.

[0046] As better shown in Figure 2, the torso frame 350 is of the type known in the defence industry as a DEI 1606 airborne assault frame. The torso frame 350 includes various harness attachment points for enabling attachment of the harness

arrangement 400 thereto. The harness arrangement 400 typically includes shoulder straps and a waist or hip belt/strap.

[0047] The input assembly 100 includes an input housing 102 which is arranged to be secured to the torso frame 350 using appropriate fasteners or to be integrally formed therewith. In Figure 2, the input housing 102 includes a cover 104 and is provisioned for four Bowden cables 300. Only the upper part of the four Bowden cables 300 are illustrated in Figure 2. [0048] Figure 3 shows the input housing 102 of the assembly 100 with the cover 104 removed. As will become apparent from later description, in Figure 3 the upper most end of each inner cable 304 is not as yet configured for load transfer. However, the outer sheath 302 of each Bowden cable 300 is shown restrained from movement by fixedly securing the outer sheath 302 of the each cable 300 to the input housing 102. This is achieved by securing a clamp 105 about the Bowden cables 300 and to the input housing 102. The configuration of the clamp 105 will vary depending on the number of Bowden cables 300 in use.

[0049] Figure 4 shows the same input housing 102 with cover 104 removed.

However, only two Bowden cables 300 are provided and the upper most ends of the inner cables 304 of the Bowden cables 300 are not as yet configured for load transfer.

[0050] The input housing 102 provides a rigid mounting for the clamp 105 so as to restrain movement of the outer sheaths 302 of the Bowden cables 300 and to also ensure that all other components located therewithin which are arranged for linear movement remain appropriately aligned. To this end, the input housing 102 may include at least one stiffening ridge 102b extending vertically there along configured to prevent twisting or bending of the input housing 102 when loaded with pack weight.

[0051 ] As shown in Figures 3 and 4, located within the input housing 102 are four mounts (two upper mounts 106a and two lower mounts 106b), two members 108, an upper load carriage 1 10, a lower load carriage 1 12 and a two load springs 1 14.

[0052] The mounts 106a, 106b are configured within the housing 102 so that the two members 108 can be mounted substantially vertically therewithin with their respective longitudinal axes parallel to one another. The members 108 are preferably precision ground rods 108 and are made from hardened stainless steel.

[0053] The upper load carriage 1 10 and lower load carriage 1 12 are each connected between the rods 108 via respective bearings 1 16. The bearings 1 16 are preferably mounted with a loose press fit with an O-ring interface for self-alignment.

[0054] The upper and lower load carriages 1 10, 1 12 are arranged for movement upwardly and downwardly along the length direction of the rods 108 and generally between the upper and lower mounts 1 06a, 106b. Each load spring 1 14 is located about its respective rod 108 and is positioned between the upper and lower load carriages 1 10, 1 12. Maximum downward movement of the lower load carriage 1 12 occurs when the lower load carriage 1 12 (or associated bearing 1 16) engages against the lower mounts 106b. However, if the system 10 is correctly calibrated and set up for the user, maximum downward movement of the lower load carriage 1 12 should never occur (i.e. the lower load carriage 1 12 should never strike the lower mounts 106b during use).

[0055] As best shown in Figure 5, a threaded rod 120 with adjustment knob 120a has a shank arranged for threaded engagement with the upper load carriage 1 10. The lowermost end 120b of the threaded rod 120 sets the length of permissible downward travel of the upper carriage 1 10 along the length of the rods 108 when the upper carriage 1 10 is subject to a downward load. This is because downward movement of the upper load carriage 1 10 is prevented once the lowermost end 120b of the rod 120 engages against a bearing surface 102c formed on the input housing 102. Accordingly, the greater the amount of the threaded rod 1 20 exposed above the upper load carriage 1 10, the greater the amount of travel of the upper load carriage 1 10 in the downward direction along the rods 108 when a downward load is applied. As the amount of travel of the upper load carriage 1 10 increases, so too does the compression of the load springs 1 14. The more the load springs 1 14 are able to compress, the greater load they can transfer to the lower load carriage 1 12, and as will be explained later, the greater the load that can also be transferred via the

Bowden cables 300 to the ground whilst bypassing the user's musculoskeletal system.

[0056] In accordance with the illustrated embodiment, the load springs 1 14 each have a spring rate of / =9.63 N/mm. They compress at a combined rate of 19.3N/mm. Any load not transferred to the load springs 1 14 and thus to the lower carriage 1 12 is transferred through the torso frame 350 and directly to the user. Typically, the load transferred to the torso frame 350 will be borne by the user's shoulders and hips, and thereby through to their musculoskeletal system. It will thus be appreciated that the threaded rod 120 acts as a load adjustment device that a user may control to adjust the amount of load actually transferred via the torso frame 350 and harness

arrangement 400 and thus to their musculoskeletal system. This adjustment can be made during use of the system 10. [0057] Any load transferred to the lower carriage 1 12 via the springs 1 14 is in turn transferred to the ground bypassing the user's musculoskeletal system via the Bowden cables 300. This transfer of load will be explained further below.

[0058] Figures 6 and 7 illustrate the use of four Bowden cables 300 within the input assembly 100. As shown in Figure 6 and with the lower carriage 1 12 not shown, when a four Bowden cable 300 arrangement is in use, a spring compensator arrangement 122 is provided to each pair of cables 300 to ensure more even distribution of the applied load between the cables 300 of each pair. Such a spring compensator arrangement may also be used to bridge the cables 300 in a two Bowden cable 300 set up.

[0059] Each spring compensator arrangement 1 22 includes an upper load bar 124, a pair of springs 126, and a pair of threaded adjustors 128. The threaded adjustors 128 are each arranged to be connected the uppermost end of the associated threaded inner cable 304 so that the tip of the inner cable 304 is located within the associated spring 126. The upper face of the load bar 124 includes a protrusion 124a that in use establishes contact with the underside of the lower load carriage 1 12. When the underside of the lower load carriage 1 12 moves downwardly it presses downwardly on the protrusion 124a. If the load bar 124 is not extending substantially horizontally when load is applied, the springs 126 will be caused to compress or expand causing the load bar 124 to see-saw so as to balance the load applied to each of the associated inner cables 304 of the two Bowden cables 300.

[0060] Small differences in the height of the uppermost ends of the inner cables 304 can be accommodated for by the springs 126 of the spring compensator arrangements 122. Further, during installation of the Bowden cables 300 within the input housing 102, the threaded adjustors 128 can be used to correct for any height differences visually apparent. The spring compensator arrangement 122 has considerably lower stiffness than the inner cable 304 alone. This results in a lower force differential between the inner cables 304 once they are all even in length and start transferring load, as compared to relying on the cable spring stiffness only.

[0061 ] Figure 7 best illustrates the underside of the lower load carriage 1 12 and the two load cavities 1 12a formed therein. Each load cavity may receive a load cells (not illustrated) for measuring the load being transferred to the Bowden cables 300. When load cells are mounted with the cavities 1 12a, the channels 1 12b provide relief for the cables (not shown) of the load cells (not shown).

[0062] Figure 7 also depicts the positioning of each of the inner cables 304 of the Bowden cables 300 with respect to the load cavities 1 12a. As shown, the inner cables 304 are mounted slightly angled so as to be positioned such that the resultant output force of each pair of inner cables 304 is located centrally of the load cavity 1 12a. It is advantageous if the output force of each pair of inner cables 304 acts as close to the centreline of the linear bearings 1 16 as possible. The further away the force acts form the centreline in any direction, the more torque is produced, resulting in increased losses due to friction in the bearings 1 16.

[0063] Figure 8 illustrates the positioning of the inner cables 300 in a two Bowden cable 300 setup. As clearly shown, the inner cables 304 of the Bowden cables 300 are centred in the load cavities 1 12a and centred with respect to the centreline of the linear bearings 1 16 of the lower load carriage 1 12.

[0064] Figure 9 illustrates the engagement between the underside of the lower load carriage 1 12, and the inner cables 304 of a two Bowden cable 300 arrangement. As shown, the inner cable 304 of each Bowden cable 300 is fitted with a spring compensator arrangement in the form of a spring 126' and a threaded adjustor 128'.

[0065] As mentioned previously, Figure 10 illustrates the pack frame 20 fitted with the input mount 22. The input mount 22 provides the means by which the pack frame 20, with attached pack (not shown), is mounted on the input assembly 100 which is being worn by the user. The input mount 22 is preferably located centrally of the width of the pack frame 20. Figure 10 depicts the upper load carriage 1 10 of the input assembly 100 to better illustrate the intended connection between the input mount 22 and the input assembly 1 00.

[0066] The input mount 22 includes a male part, shown as a ball 24, arranged to be located within a female part, shown as a circular shaped socket 1 10a, formed in an upper face of the upper carriage 1 10. The socket 1 10a has a generous depth to ensure that the ball 24 will be retained therein despite any backwards pull resulting from the pack load. A lead-in 1 10b is provided about the upper circumference of the socket 1 10a to assist location of the ball 24 within the socket 1 10 when donning the pack. It is envisaged that a deep V-shaped lead-in (not illustrated) may be provided to assist with the location of the ball 24 within the socket 1 10 of the input assembly 100.

[0067] The ball and socket type connection between the pack frame 20 and the input assembly 100 allows for easy donning and doffing of a pack even when heavily load. The ability for a user to quickly doff a pack is vital as it enables the user in an emergency situation to quickly discard their pack. Figure 10 also better illustrates the threaded aperture 1 10c through which the threaded rod 120 is received.

[0068] Figures 1 1 to 13 illustrate the output assembly 200 of the system 10. In Figures 1 1 and 12, only the lower part of the Bowden cables 300 are depicted and in Figure 13 for clarity reasons, the Bowden cables 300 are not shown.

[0069] The output assembly 200 is in the form of a leg brace 210 designed to be worn about the leg of the user and which further includes a boot brace 220 and a load transfer assembly 240 for each cable 300. In Figures 1 , 1 1 and 12, the output assembly 200 is configured to receive two Bowden cables 300 and as such each leg brace 210 includes two load transfer assemblies 240. The load transfer assemblies 240 are located on the leg brace 210 so as to be positioned either side of the user's leg (i.e. on the outer side and on the inner side of the leg).

[0070] The boot brace 220 is arranged for connection to the user's boot 500 whilst still allowing up and down movement of the user's foot about the ankle joint. The boot brace 220 is configured to apply the transfer load (i.e. the load transferred by the lower carriage 1 12 to the inner cables 304 of the Bowden cables 300) to the sole of the user's boot 500 and thus directly to the ground. The boot brace 220 is preferably connected to the sole of the user's boot 500 via screws arranged to be received in threaded inserts embedded in the sole.

[0071 ] As best shown in Figure 1 , the Bowden cables 300 extend between the input assembly 100 and the output assembly 200. In order to prevent the Bowden cables 300 from protruding away from the user's body, which might represent a catch hazard for the user, a brace or other strapping 600 is provided along an upper part of each of the user's leg. The Bowden cable(s) 300 associated with each leg can then be secured thereto. For example, a VELCRO® type connection might be established to hold the cable 300 against the brace or strapping 600.

[0072] As shown in Figure 13, the leg brace 210 of the output assembly 200 is arranged to be secured about the user's leg and below their knee by means of a first adjustable strap 212. A second adjustable strap 214 extends generally vertically and connects between an upper support 210a of the leg brace 210 and an ankle/foot brace (not visible) worn by the user. The ankle brace may adopt the form of a conventional ankle support or brace which is firmly connected to the user's ankle and is thus located within the boot 500. It is envisaged that for ease of use and to avoid the necessity for the user to wear a sock and an ankle brace, the ankle brace may be modified to further include or be formed as part of a sock.

[0073] During use of the system 10, the ankle/foot brace is firmly secured to the user's ankle/foot and is connected to the leg brace 210 under tension by the second strap 214 to establish a counter load path. More particularly, downward load transferred from the input assembly 100 by each inner cable 304 to the output assembly 200 is transferred to the sole of the user's boot 500. That downward load is opposed by tension in the second strap 214 generating an upward force which holds the outer sheath 302 of each Bowden cable 300 in place linearly. It will be

appreciated by those skilled in the art that if the load system of the boot 500 was fully enclosed, that is if the outer sheaths 302 of the Bowden cables 300 receiving the opposing force and the inner cable 304 applying the transfer load were both connected to the boot 500, the applied load would tear the boot 500 apart. To avoid this from happening, and in accordance with an embodiment of the invention, the arrangement is configured so that the boot 500 is effectively being pushed away from the user's leg. More particularly, the arrangement is such that if there was no ground under the sole of the user's boot 500, the boot 500 would effectively be pushed off the user's foot. It will be noted that when the user is in a single stance position (i.e. one foot on the ground and one leg in the swing phase), the boot on the leg in swing phase is not pushed off the foot as there is limited travel of the inner cable because the system is in equilibrium when at least one foot is in contact with the ground.

[0074] It will thus be appreciated that transfer load at the output point of the inner cable 304 to the boot 500 must be pushing away from the user for the system 10 to work (i.e. to transfer load off the user and to the ground). This is facilitated by the sliding attachment of the load transfer assembly 240 relative to the boot brace 220. This sliding attachment maintains linear alignment, but allows lineal movement.

[0075] The loading forces within the output assembly 200 during use of the system 10 can be summarised as:

Downward force is applied to the top of the inner cable 304 of the Bowden cable 300;

Downward force is applied to the load transfer assembly 240 and the boot brace 220;

Downward force is applied to the boot 500 and sole thereof;

Downward force is applied to the ground via contact with the sole od the user's boot 500

Upward force is applied on the bottom of outer sheath 302 of the Bowden cable 300;

• Upward force is applied on the connection housing 246 and the leg brace 210;

• Upward force is applied on the top of strap 214 attached to ankle/foot brace worn by the user;

• Upward force applied on the sole of the user's foot and ankle of their foot;

• The resultant force is downwards to ground.

[0076] The tension in the first strap 212 is preferably adjusted to maintain each load transfer assembly 240 vertically in-line with the user's lower leg. The leg brace 210 may include one or more stiffening members, for example stiffening ribs, along the vertical parts of the leg brace 210 to minimise torques movement about the lower leg of the user. [0077] One of the cable load transfer assemblies 240 of the leg brace 210 is best illustrated in Figure 12. As shown, the load transfer assembly 240 is configured to hold the Bowden cable 300 in linear alignment with the user's leg during use of the device and is also configured via a clamp 250 to allow relatively fast Bowden cable changes. Load cells may be mounted to the load transfer assembly 240 to allow measurement of achieved output loads.

[0078] The transfer assembly 240 is mounted on a mounting plate 241 which is arranged for connection with a lower support 210b of the leg brace 210. The mounting assembly 240 includes a bracket 242, shaft 244, and a connection housing 246. The connection housing 246 houses a bearing 248 and is configured to move upwardly and downwardly along the shaft 244.

[0079] The connection housing 246 also receives a part of the lower end of the Bowden cable 300 with the inner cable 304 of the Bowden cable 300 extending there through so as to be connected to the lower end of the bracket 242. The outer sheath 302 of the Bowden cable 300 is secured to the lower support 210b of the leg brace 210 via a clamp 250. The lower end of the bracket 242 connects via a pivot joint 252 to the boot brace 220. The pivot joint 252 enables the boot brace 220 to pivot about an axis extending generally perpendicular to the longitudinal axis of the shaft 248.

[0080] The pivot joint 252 is closely aligned in use with the user's ankle so that the load transfer is also so aligned minimising torque transfer to the user.

[0081 ] The use of a four Bowden cables 300, two per leg of the user, is another option, particularly for input loads greater than about 20kg. With such an

arrangement, a Bowden cable 300 is preferably configured to run down each side of the leg.

[0082] Figure 14 illustrates a modified torso frame 800 for use in an exoskeleton system 900 according to another embodiment of the invention including two Bowden cables 300. The torso frame 800 includes a hinge point or zone 802 to facilitate flexure of the torso frame 800 in the region of the waist area of the user. This allows twisting and bending movements by the user without undue impediment by the torso frame 800. The torso frame 800 further includes a pair of elongate generally vertically extending slots 804. These slots 804 in conjunction with a slide connector 806 provide means for adjusting the length of the Bowden cables 300 for different height users (i.e. means for adjusting the length of cable 300 running down the length of the user's leg with any cable slack retained between the slide connector 806 and connector 807). Slide connector 806 also serves to restrain the outer sheath of each cable 300 preventing movement thereof when upward or downward force is applied to the Bowden cable 300. Each Bowden cable 300 is further secured to a belt and thigh brace assembly 900 which connects to a lower part of the torso frame 800. As best shown in Figures 14 and 15, each Bowden cable 300 is secured at the side waist region of the user via respective connectors 807. These connectors 807, which adopt the form of clamps, hold the outer sheath of the Bowden cable 300 substantially vertically and prevent upward or downward movement thereof when load forces are applied. Other forms of connectors 807 are envisaged.

[0083] An upper part of the torso frame 800 provides a mounting aperture 808 for receiving an input assembly 100 and the lower part of the torso frame 800 is arranged for connection to the belt and thigh brace assembly 900. The upper part of the torso frame 800 is also arranged for connection to an harness arrangement 400.

[0084] It will be noted that the belt and thigh brace assembly 900 includes two thigh restraints 902. The thigh restraints 902 include straps 904 for securing the thigh restraints 902 to the thigh portion of the user, but other means for securing the thigh restraints 902 are envisaged. The thigh restraints 902 are configured to hold the outer sheath of each Bowden cable 300 firmly against the user's leg (i.e. one against the thigh of the right leg and the other against the thigh of the left leg) and to minimise undesired rotation of the Bowden cables 300 during movement of the user. It is preferable in so far as reasonably possible to maintain the outer sheaths of the Bowden cables 300 in parallel alignment with the user's thigh during gate of the user.

[0085] It has been found that buckling of the cable 300 below the user's waist reduces the efficiency of the load transfer system. This is understood to occur because such buckling causes a reactive force to be established in the outer sheath 302 of the cable 300 and that reactive force is exerted on the user. Given this, it is desirable to prevent the thigh brace assembly 900 from rotating. [0086] Figure 17 illustrates a variation to the leg brace 210 of the output assembly shown in Figure 13. The leg brace 910 shown in Figure 17 is configured to be located against the user's lower leg in the region of the shin rather than being located against the user's calf. Such a variation is anticipated to suit more users because the user's calf size does not have a significant impact on wearability. Leg brace 210 may include an adjustable connector for the cable 300 so as to allow the connection point of the cable 300 to the leg brace 210 to be adjusted to better suit the particular user.

[0087] Figures 18A and 18B illustrate schematically a torso frame 920 connected to a belt assembly 930 and thigh brace assembly 940. In these Figures, only the right belt assembly and the right leg brace assembly 940 are depicted. As indicated by the arrows in Figures 18A and 18B, the connection between the illustrated belt assembly 930 and leg brace assembly is independently adjustable in both the lateral and linear directions. This adjustably enables the exoskeleton system to be better tailored to the body size of the particular user. For example, it is understood that user experience of the system is enhanced by correctly establishing the overall free length of the cable 300 across the joint centres of the user's hip and knee, by centring this free length to the user's joints, and by optimisation of the cable 300 length between the knee and boot connection of the particular user.

[0088] Figures 19A and 19B illustrate thigh plates 950 for mounting on the thigh brace assembly 940. Each thigh plate 950 is fitted with connectors 960 for securing the cable 300 at the required position on the thigh plate 950. The longitudinal positioning of each connector 960 on the thigh plate 950 is adjustable via the slots 962 and fasteners 964.

[0089] Figure 20 illustrates an adjustable connector 970 for mounting on a plate 972 which is in turn arranged for connection to the belt assembly 930. As shown, the connector 970 includes a curved channel 974 for receiving the cable 300 and for gently bending the same whilst it is clamped by the connectors 976 to the plate 972. Slot 978 enables the positioning of the connector 970 on the plate 972 to be adjusted.

[0090] It is expected that there will be a learning curve for optimising the compound setup for maximum load transfer to the ground and minimizing impact to gait for individual users. This optimal set up may vary with physiology. For example, the cable length below torso frame 350 should be adjusted to the optimised length to match the limb with no excess, and free cable length across the knee should be centred to the knee.

[0091 ] Figure 21 illustrates a mechanism 1000 for user adjustment of the load that is transferred to their musculoskeletal system. Previously, it was explained in relation to the embodiment shown in Figure 5 that adjustment of the load transferred to the user's musculoskeletal system could be made by rotating the threaded rod 120.

However, such adjustment needed to be made by a third party whilst the exoskeleton system 10 was being worn by the user. To overcome the requirement for third party involvement, the mechanism 1000 as shown in Figure 21 has been developed. This mechanism 1000 includes a flexible drive shaft 1002 that can be operated by the user to rotate the threaded rod 120. A reduction in load force will allow the cable 300 to move more freely at the leg joints but more load will be shifted to the torso frame 250 and harness arrangement 400 and thereby to the user's torso. Accordingly, the user has the capability to adjust the amount of load transferred to the torso frame during use of the exoskeleton system (i.e. whilst being worn).

[0092] Embodiments of the present invention may have differing further

advantages depending on set up and/or the particular user and/or other factors. It is envisaged that such advantages over the prior art may include, by way of example only,:

• the system having significantly less mass, especially distal mass, than typical prior art exoskeleton systems and have less impact on the human/load carriage system's centre-of-mass;

• that the system does not attempt to mimic human kinematics. The Bowden cables do not have to align exactly with the wearer's skeleton;

• that the system is light in weight compared to typical rigid-linked prior art

exoskeletons;

• that the system has low distal weight (e.g. weight on the feet) and distal weight contributes to high metabolic cost during locomotion; • that when not required the cables of the system can be packed away with little encumbrance to the user;

• that the system is low cost compared to conventional exoskeleton systems;

• that the system has a relatively simple design and no requirement for

electronic systems or power supply and are thus less likely to fail during use;

• that the system does not include any sort of knee, hip or spine joint;

• that the system does not create noise during use and thus is advantageous where stealth is required.

[0093] Throughout the previous description and the following claims, reference is made to transferring a load from one part or component of the system to another or from the system or a part or component of that system to the ground. It will be appreciated by those skilled in the art that the effectiveness of each such transfer will vary and that load transfer at each transfer point will be impacted by many different factors. It should thus be understood that reference to a load transferring from one part or component to another is not intended to indicate that a 100% effective load transfer is necessarily achieved.

[0094] The embodiments have been described by way of example only and modifications within the spirit and scope of the invention are envisaged.