Technical Field

The invention is part of the mechatronics and robotics field and covers a type of robot. The invention refers to an exoskeleton device, which interacts with a human operator improving the user’s physical capabilities regarding the manual carrying of additional equipment and cargo and is applicable in an industrial environment as well as in military and rescue activities and others.

Background Art

In the PCT publication WO2011127471 Al, which is considered by this application part of the state of the art, is disclosed a device of the type electrically powered exoskeleton intended to improve the human user' s cargo carrying capacity, in this application the equipment and or cargo carried on the user' s back is utilized to counter balance any load that is attached at the front of the user and in this application the legs are powered via electrical and hydraulic systems, the control system utilized is one based on sensors using electricity. The exoskeleton disclosed in WO2011127471 Al consists of a torso section connected to the leg section via a hip joint section, where the leg section consists of two symmetrical legs, where each leg consists of sequentially connected to each other a foot section, ankle section, calf section, knee joint and tight element. The drawbacks of the described device are its need for batteries and/or electrical components which certain groups such as for example military personnel find undesirable due to their vulnerability in field conditions and are a logistics complication. Another drawback of the described device is the elongated sole one the foot segment underneath the user' s toes and the absence of a mechanism separating the sole into a toe and rest of the foot sections. This is a substantial drawback due to the natural walking cycle of a human where the human uses their front part of the foot to push themselves forward at the end of the gait cycle thus transmitting a significant amount of force through the front part of the foot, since there is an absence of a mechanism in the exoskeleton' s shoe to compliment the natural exertion being carried out the entire weight of the exoskeleton and carried load ends up being transferred through the joints and soft tissues of the user. This load transfer causes noticeable discomfort even over a short period of time and it will cause traumas in the long term due to premature joint wear, a type of injury already prevalent with heavy physical activity such as military service.

In the PCT publication WO2015192240A1, which is considered by this application as part of the state of the art, is disclosed an exoskeleton device, which utilizes passive geometry to transfer the load from carried cargo and or equipment to the ground. In this device there is no force amplification being delivered to the user. In the described device there is also no component which goes underneath the user' s front foot portion and toes. Therefore at the push off phase of the walking gait the entirety of the exoskeleton weight and carried cargo and or equipment is being taken up the user' s joints and soft tissues located at the front end of the user's foot. This load transfer causes noticeable discomfort even over a short period of time and it will cause traumas in the long term due to premature joint wear, a type of injury already prevalent with heavy physical activity such as military service.

This application also considers as prior art a device developed by Carnegie Mellon University USA (http://biomechatronics.cit.cmu.edu/publications/Collins 2015 Nature— Photos. html) as well as their publication from 2015 Collins, S.H.,Wiggin, M.B., Sawicki, G.S. (2015 ) Reducing the energy cost of human walking using an unpowered exoskeleton. Nature, 522 (http://biomechatronics.cit.cmu.edu/publications/Collins 2015 Nature.pdf)

, in which device by utilizing a spring and a ratchet type clutch is achieved a reduction in the metabolic energy consumption during walking. In the described machine the structure only encompasses the foot, ankle and calf and does not directly participate in any load reduction if the user is carrying additional weight. The drawbacks of this device is that any reactive forces from the mechanism working are directly transmitted into the tissue of the user and that the user needs to lift up the weight of the device every time they move their leg forward.

The main drawback of the device described in WO2011127471 Al, which is considered as the closes one functionally and conceptually to the present invention disclosed in this application, is the need for the use of an active energy consumption element (s), such as batteries for the generation of its additional motive force, electric motors, other electronics, and another drawback is the construction of its foot segments which do not adequately deal with the load transfer to the ground thus causing discomfort and trauma over prolonged used. Therefore, the technical problem of providing an exoskeleton to be powered by energy supplied entirely by the wearer's weight, the exoskeleton itself and the possible load, and being comfortable and safe for the end user, cannot be solved by the exoskeleton such as that of WO2011127471 Al.

Disclosure of Invention

It is therefore the object of the invention to provide an exoskeleton of the type as described in WO20111274A1 and according to the preamble of claim 1, which exoskeleton is powered by using the energy generated entirely from the weight of the user, the exoskeleton device itself as well as any cargo being carried, without the use of component/components with an active energy use requirement , such as batteries, electrical motors and other electronics, and which further helps to reduce the load carried by the user by encompassing more of the user' s body without creating a use situation predisposing the user to long term trauma. This object is achieved by an exoskeleton in accordance with the combination of features as described in the independent patent claim 1.

According to the independent claim 1 the foot section of the exoskeleton includes separate foot elements, of which one of them serves to cover area underneath the front portion of the foot and the toes, this element has a moving connection to the other foot element which covers the bridge of the foot and the heel of the user. With this construction the weight of the device and carried cargo is carried through the exoskeleton during the push off phase of the gait rather than solely through the joints and soft tissues of the user's foot, this in turn prevents discomfort and joint wear and or other potential traumas. Additionally, the calf mechanism box comprises comprises pivotally connected to it at least one lever controlling movement of ankle joint and at least one large gear wheel, connected to each other via at least one spring like element, configured such that it behaves as a solid element when the user desires to stand up and as a soft element exerting resisting force when the user wishes to crouch. The thigh element which at one of its two ends has a gear wheel like profile and at its other end is free to be connected to other elements, such as for example a regulating element. The exoskeleton’s hip joint box comprises a fixed to it plate and at least one spring like element for generation of motive force required to lift the leg, one end of which spring like element terminates by attaching to the plate. Wherein the tight element is axially connected to the calf mechanism box in such a way that the large gear wheel can interact with the gear like profile of the tight element, in which interaction the connection between the tight element and the calf mechanism box forms the knee joint and at the opposite end of the tight element is attached an element for lifting the leg by being attached to the spring element. Additionally, the artificial ligament is attached at one of its two ends to the front facing portion of the foot element then wound underneath the flexible connection, which connects the foot elements, continuing along the full length of the foot section where at the end point of the foot element the artificial ligament is guided upwards along the leg and is attached at its other end to the lever controlling the movement of the ankle joint.

When the term“spring like element“or the like is used the intended meaning is to describe a component which behaves like a spring without defining limitations as to what specific type and or design of spring or springs is being used.

By combining the above described features the control of the exoskeleton by the user is facilitated by the interface between the entire body of the operator and the device itself, following the natural movements of the operator where the generation of the additional assistive force is accomplished entirely by the use of mechanical components and not by the use of components with an active consumption of energy.

The exoskeleton becomes operational and follows its user s movement the moment the soles of the exoskeleton make contact with a surface. This activation occurs when the load of the operator, exoskeleton and carried weight begins the press down on the foot elements of the exoskeleton in conjunction with the operator straightening his/ hers leg/s to stand up. When these conditions are met the foot elements of the exoskeleton will begin rotation around the ankle joint thus applying tension to the artificial ligament which connects the foot element underneath the toes and the foot element underneath the bridge and heel of the foot with the calf mechanism box. When the artificial ligament is tensioned the calf mechanism box is placed in a position parallel with the calf of the operator and the same time the mechanism located inside the calf mechanism box is activated, and in turn starts to move the tight element to a position approximately in line with the position of the calf mechanism box. The described motion results in the exoskeleton coming in line with the upright leg of the user and locking itself. This locked state persists until the user decides to step forward.

When the user initiates a forward step the weight transfer from the lifted to the pushing leg occurs naturally and relieves the load applied to the leg that is above to be lifted forward. This relieve in load allows for the spring element located in the hip joint box to lift up the leg being moved forward as well as to apply a small amount of motive force assisting in lifting the actual leg of the user. In this way the user does not have to lift the weight of the exoskeleton leg.

When the leg is raised up and the knee is bend, the mechanism located in the calf mechanism box will cause the front point of the foot of the exoskeleton to point downwards resulting in placing the leg of the user in a knee up toes down position. The angle achieved is with reduced acuteness compared to the angle of the knee joint due to the gearing in the calf mechanism box. The motion occurs since the spring like element in the calf mechanism box acts as a rigid component and is necessary in order to unlock the exoskeleton leg and make it flexible, while not causing discomfort in the user due to being barely perceptible.

When the user decides to assume a crouching position the ankle motion described in the above paragraph cannot take place due to the exoskeleton foot elements making contact with the surface on which the operator stands. In that situation the mechanism in the calf mechanism box begins to compress the spring like elements storing the energy of the downwards motion to be used in aiding the standing up process. When crouching there is provision for the user to raise their heels assuming a position which allows him/her to quickly raise the exoskeleton up by pressing down with their heels thus initiating the standup cycle. This pressing down motion in conjunction with the energy stored in the springs will bring the device and user to an upright position.

In a climbing situation when one leg is raised up to be placed on a higher up surface the user can begin transferring their weight onto the exoskeleton sole which is in the toes down heel up position making contact with the higher up surface and thus can use the same standing up cycle to generate an assistive force for raising up the device and user to the higher elevation.

When the user is standing still and upright the weight of the carried cargo and the user' s upright stance serve to negate the motive force generated by the spring like element/s located in the hip box thus achieving a natural resting position. All of the above is carried out without the use of electrical or other components requiring charging/ fueling.

The preferred embodiments of the exoskeleton are further described in the dependent patent claims 2 through to 15.

According to the first preferred embodiment of the invention the spring elements of the hip joint box and calf mechanism box are springs which create a motive force to power the calf mechanism.

According to another preferred embodiment, the springs are gas springs and/ or coil springs. In terms of how the mechanism performs their core function there is no difference between the use of gas or coil springs. The choice of the type of spring used is determined by secondary factors such as cost and noise with the gas springs being quieter but more expensive. On the other hand utilizing coil springs will result in the machine having a lower production cost, due to the lower pricing of coil springs. Using a combination of the two types of springs is also possible and can be utilized depending on additional requirements and financial resources.

In another embodiment of the invention, the lever controlling the movement of the ankle comprises at its one end a shaped as a spool element around which the artificial ligament is wounded and at its other end a lever, wherein the lever controlling the movement the ankle is axially connected to the calf mechanism box, preferably via a bearing

In another embodiment of the invention, the lever controlling the movement of the ankle and the large gear wheel are connected to the spring like element via axles, and the large gear wheel is axially connected to the calf mechanism box, preferably via a bearing.

In another embodiment the artificial ligament connecting the foot components with the calf mechanism box is made of a stretch resistant material for example but not limited to a steel cable. The material being soft and pliable when there is no force going through it serves to provide agility and control of the ankle joint.

In another embodiment, the tight element is attached to the calf mechanism box via movement limiter for limiting the movement of the created by the tight element and calf mechanism box knee joint.

In another embodiment, the artificial ligament consists of a soft, flexible element produced out of a stretching resistant material, for example a steel cable or other similar materials. The soft and stretch resistant material provides mobility and control over the spherical bearing serving as an ankle joint.

In another embodiment, the tight element is connected to the calf mechanism box via an angular contact bearing. It is strongly recommended that the bearings used are angular contact bearings, due to the high concentration of stresses which accumulate at the knee joint and bearings of a different construction are prone to breakages, i.e. the angular contact bearings reinforce the construction.

In another embodiment, the leg lifting element is shaped as a hook. The hook for lifting the leg allows for the transmission of the motive force to the leg during its lifting.

In another embodiment, the length of the plate in the hip box is selected such that it serves to regulate the pre-tension exerted on the spring like element.

In another embodiment, the artificial ligament is attached to the ratchet mechanism after it comes out of the foot element thus having the ability to have its tension adjusted.

In another embodiment, the foot elements are axially connected to each other, preferably via a hinge. The hinge allows the device to imitate the natural movement of the user' s toes.

In another embodiment, the foot element which is located underneath the bridge of the foot and heel is connected via a spherical type bearing to the calf mechanism box. This spherical type bearing serves as the exo skeleton s ankle joint.

In another embodiment, each of the legs is connected to the hip joint box via a six degrees of freedom joint which bearing serves as the exo skeleton s hip joint permitting a free range of motion without the need of additional force being applied by the user.

Brief Description of Drawings

Figure 1 shows an isometric view of the exoskeleton Figure 2 shows a left side view of the exoskeleton Figure 3 shows a rear view of the exoskeleton Figure 4 shows a close up view of the calf mechanism box Figure 5 shows a section view of the calf mechanism box

Figure 6 shows a close up of the ankle and a section view of the calf mechanism box Figure 7 shows an isometric view of the exoskeleton foot.

Figure 8 shows a section view of the exoskeleton hip mechanism Figure 9 shows a close up of the rear of the exoskeleton Figure 10 shows a close up of the front upper part of the exoskeleton List of components:

1- Exoskeleton torso. The upper part of the exoskeleton

2- Legs. The lower part of the exoskeleton torso 2(L) ; 2(R) - Exoskeleton legs

3- Foot element which is located underneath the bridge of the foot and heel of the operator

4- Foot element which is located underneath the toes of the user

5- Spherical bearing

6- Adjustment block - Profile serving a structural purpose. The profiles annotated with the number 7 are of various lengths depending where they are located on the exoskeleton

- Calf mechanism box

- Tight element

0- Belts with buckles

1- Leg lifting hook

2- Hip joint box

3- Carry handle

4- Back brace plate

5- Back rest

6- Cargo mount supports

7- Artificial ligament

8- Adjustment ratchet

9- Hinge connecting elements 3 and 4

0- Buckles

1- Lever controlling the ankle motion

2- Bearing for the lever controlling the ankle motion

3- Spring element

4- Large gear wheel

5- Bearing for the large gear wheel

6- Angular contact bearing for the knee joint

7- Motion limiter for the knee joint

8- Rubber components attached to the components 3 and 4 serving as soles

9- Spherical bearing serving as a hip joint 30- Spring like element providing the motive force for lifting the leg

31- Plate serving to adjust the pre-load of the spring like element 30

32- Quick attachment points for cargo

33- An adjustment block different from the adjustment block 6 allowing for the raising and lowering of the forward cargo carrying mounts depending on user' s height.

Best Mode for Carrying Out the Invention

An example embodiment of the invention is described. The drawings supplied are not scale drawings and only serve an illustrative purpose. The disclosed embodiment does not limit the invention to the displayed combination of elements which can be assembled in a different way and achieve partial usefulness.

Figure 1 showcases an isometric view of the invention where the main visible elements are showcased and labeled. The device can be divided into two primary sub sections. Section 1 the torso, consisting of all elements which are located at waist level and up using the human operator as reference. Sector 2 encompasses all of the elements which constitute the legs, of which there are two of and they are symmetrical, and are located below the waist line of the human operator.

Figure 1 shows that the device is constructed as follows, starting from the bottom moving upwards. At the lowest point of section 2, respectively at the lowest point of the legs 2(L)(R) are located the foot elements 4 and 3. Element 4 is a foot element which supports the toes of the user's foot. The foot element 4 is axially connected to foot element 3 via the hinge 19. The hinge 19 allows the mechanism to mimic the natural movement of the user's toes. Element 3 is the foot element which covers the area underneath the bridge of the user' s foot and the user' s heel.

Continuing through Figure 1, the component 5 a spherical bearing is connected to the foot element 3. The spherical bearing 5 serves to act as an ankle joint. To the spherical bearing 5 is attached the adjustment block 6. The adjustment block 6 consists of a hollow profile to which there are threaded element/elements attached, for example welded nuts and this thread/threads are used to hold a bolt/bolts. The profile 7 fits inside the adjustment block 6. The profiles labeled as 7 are present at several locations in the device. The elements labeled as profile 7 are of the same or similar cross section but of varying lengths. The adjustment block 6 by the use of the bolt/ bolts threaded into it clamps onto one end of the profile 7 and in this way builds the structural portion of the machine. Each profile 7 terminates on each of its two ends in an adjustment block 6.

The combining of the adjustment blocks 6 and profiles 7 permits alterations of the exoskeleton' s dimensions. A significant size change is accomplished by swapping out the profiles 7 with others which have a greater or lesser length. The fine adjustment in size is done by loosening and tightening the bolt/bolts in the adjustment block 6 and the incremental sliding of the profile 7.

In figure 1 after the first set of two adjustment blocks 6 and one profile 7 is attached the calf mechanism box 8. The calf mechanism box 8 is attached to the adjustment block 6. The calf mechanism box 8 contains essential for the operation of the machine components, which components are further described in detail further below. The calf mechanism box 8 is connected via a bearing joint to the tight element 9. The tight element 9 consists of, for example plates which at one of their two ends are shaped as gear wheels and contain angular contact bearings and at its other end is fixed to an adjustment block 6. The connection between the tight element 9 and the calf mechanism box 8 serves the purpose of a knee joint for the machine allowing the machine to follow the natural movement of the operator.

In figure 1 the thigh element 9 terminates at its upper end into an adjustment block 6. This adjustment block 6 contains a profile 7 followed by another adjustment block 6. Around this profile 7 a fastening strap 10 is wrapped. The strap 10 consists of a strap and a buckle/buckles. The strap 10 is called out at several locations in the figures and the strap 10 as the profile 7 varies in terms of length according to the location at which it is installed. In this particular instance the strap 10 which is localized close to the tight element 9 serves to facilitate the connection between the tight of the user and the leg 2.

In figure 1 and referring to figure 8, the leg lifting hook 11 attached to the adjustment block 6, the leg lifting hook 11 serves as an attachment point for the spring like element 30 which lifts the leg 2. The spring like element 30 in this particular embodiment of the invention is a coil spring, however it can also be a gas spring. The leg lifting hook 11 serves to transmit the motive force requited for lifting the leg 2. The leg 2 is attached to the hip box 12 by the use of a spherical bearing 29 which is visible in figure 8.

The hip joint box 12 contains the hip mechanism, which provides the motive force for lifting the leg/ legs 2. This mechanism will be described in more detail further below. The hip joint box 12 has a carry handle 13 attached to it. The carry handle 13 serves to help with the manipulation of the exoskeleton during transport, donning and doffing.

To the carry handle 13 there is attached an adjustment block 6 followed by a profile 7 followed by another adjustment block 6. To this adjustment block 6 there is permanently affixed another adjustment block 6 at a 90 degrees position followed by a profile 7. This 90 degrees attachment arrangement of the two adjustment blocks 6 serves to form a belt like structure around the user' s waist - figure 3.

To the profile 7 which connects the left and right side of the torso 1 is attached an adjustment block 6 which clamps onto a profile 7 followed by a regulating block 6. To this structure is attached the back brace plate 14 -figures 3,9 and 10. The back brace plate 14 serves as a back rest against which the user can rest their back. The back plate 14 contains attachment points for straps as well as attachment points for securing cargo. The backrest 15 is attached to the back brace plate 14. The back rest 15 is a soft upholstered component contributing to the user's comfort.

To the back rest 15 are attached the cargo mount supports 16. These cargo mount supports 16 serve as attachment points for any cargo that the user will carry upfront.

Figure 5 shows a close up side view of the leg 2. Figure 5 shows a section view of the calf mechanism box 8, as well as a section view of the foot elements 3 and 4 in order to showcase the functioning elements located within them. As previously stated the components will be described in sequence starting from the bottom end of the machine and moving upwards.

Figure 5 shows attached to the elements 3 and 4, the components 28. The components 28 are rubber like components functioning as soles for the entire machine.

Figure 5 shows the artificial ligament 17. The artificial ligament 17 consists of a soft flexible component made out of a stretch resistant material, such as for example but not limited to, a steel cable. The artificial ligament 17 is affixed to the front part of the foot element 4. The artificial ligament 17 is then wound underneath the axle of the hinge 19, which connects the elements 3 and 4. The artificial ligament 17 is then wound through the foot component 3 routing underneath the spherical bearing joint 5 which serves as an ankle joint. At the end of the element 3 the artificial ligament 17 routes around a portion of the element 3 and heads upwards along the leg 2.

The artificial ligament 17 once out of the element 3 is attached to an adjustment ratchet 18 which regulates the tension of the artificial ligament 17. Coming out of the adjustment ratchet

18 another part of the artificial ligament 17 continues upwards along the leg 2 and is attached to the lever 21 which controls the ankle joint movement. The lever 21 controlling the movement of the ankle is at one of its two ends shaped as a spool around which the artificial ligament 17 is wound and at its other end is shaped as a lever. The lever 21 which controls the ankle movement is axially connected to the calf mechanism box 8, which connection can for example be done with a bearing 22.

The lever 21 which controls the ankle movement is connected to the spring like element 23 which provides the motive force for the calf mechanism by an axle. In this embodiment of the invention the spring like component 23 is preferably a gas spring, which could also be a coil spring. The spring like element 23 is connected to the large gear wheel 24 by an axle, and the large gear wheel 24 is axially connected for example with a bearing 25 to the calf mechanism box 8. The large gear wheel 24 interacts with the gear like shaped end of the tight element 9. The tight element 9 is axially connected to the calf mechanism box by for example an angular contact bearing 26. Forward of the tight element 9 attached to the calf mechanism box is a motion range limiter 27. The limiter 27 limits the range of motion of the knee joint created by the connection between the tight element 9 and the calf mechanism box 8.

In figure 5 is shown the strap 34 attached to the element 3. The function of the strap 34 is to secure in place the heel of the user so that it can't come out of the foot mechanism. Buckles 20 are attached to the foot elements 3 and 4 and to them are attached a variation of the straps 10, which serve to secure the foot of the user to leg 2.

Figure 8 shows a close up section view of the hip box 12. The hip box 12 is sectioned in order to showcase the components within it which form the hip mechanism. Figure 8 shows the leg lift hook 11. Attached to the leg lift hook 11 is the spring like component 30. The spring like element 30 provides the motive force for lifting the leg 2. The spring like component 30 is attached at the other end to the plate 31. The plate 31 through its length serves to regulate the spring like element 30 's pre-tension. The plate 31 is fixed to the hip box 12.

Figure 9 shows a close up view of the rear of the device. Figure 9 showcases the cargo attachment points 32. The attachment points 32 are part of the back brace plate 14. The attachment points 32 serve for attaching useful cargo to the back of the user. In figure 9 is shown the adjustment block 33, which block is different from the adjustment blocks 6. The adjustment block 33 regulates the height at which the structure permitting front cargo carry is located. The adjustment block 33 consists of a C channel profile and two fasteners which allow it to attach to the profile 7.

Application of the invention

The exoskeleton is used when the operator“puts it on“by placing his/hers feet into the foot element 3 and 4 and aligns his/hers body with the calf mechanism box 8, tight element 9 and the backrest 15. When these conditions are met the operator fastens themselves to the exoskeleton by tightening the straps 10. It should be noted that for various user body sizes the length of the profiles 7 would have to be adjusted. When the operator has donned the device he/she should begin movement in accordance with their natural running, walking gait and standing up, crouching movement and obstacle overcoming movement. The machine is designed in such a way that when the weight of the operator, the machine and any eventual cargo being carried by the attachments points 32 and/or cargo mount supports 16 is going to be transferred downwards along the torso 1 and legs 2 due to the force of gravity and when the foot elements 3 and 4 are in contact with a surface capable of exerting an opposing force impulse to the combined weight, the machine will begin to rise up. This rising up motion will be due to the interaction of the artificial ligament 17 with the foot element 4 and 3, the adjustment ratchet 18, the lever 21 controlling the ankle motion, which interaction will begin rotating the calf mechanism box 8 around about the foot element 3 and 4. The artificial ligament 17 is designed in a way that it is flexible so that it can provide mobility and control of the ankle joint 5. As the calf mechanism box 8 begins its motion relative to the foot elements 3 and 4, the spring like element 23 begins to transmit movement to the large gear wheel 24, which large gear wheel 24 transmits the motion to the tight element 9. The spring like element 23 is selected with such parameters that it behaves as a solid when the operator wishes to stand up and as a soft resistive element when the operator desires to crouch.

Crouching is initiated when the operator transfers their body weight on their toes using the natural leverage created and subsequently transfers the majority of their own body weight, exoskeleton weight and any cargo weight to the foot element 4. When the transfer is complete the user can relax their body downwards. In this state the spring like component 23 will begin to compress in order to provide the force required to for crouching and will also become ready to return the energy stored back at the moment of rising up. The standing up sequence is the reverse of the crouching sequence. When wishing to stand up the operator must guide their weight to their heels pressing on the element 3. With a minimum amount of movement in the element 3 the exoskeleton will begin to rise up. When the user is upright and wishes to step forward, he / she must start by leaning their body towards the leg which will act as a support in a similar fashion to the natural gait cycle and begins to remove the weight being carried by the leg that will be moving forward. When this reduction in weight starts the spring like element 30 will being to act upon the leg lift hook 11 and the hip box 12, the result of which interaction will be the lifting of the leg 2 of the exoskeleton as well as the leg of the user in a way that will compensate for the added weight as well as reduce the effort of the operator need for lifting their own limb.

When the leg 2 is raised up, the spring like element 23 located in the calf mechanism box 8 will behave as a solid element, due to the foot elements 3 and 4 not experiencing any resistance. When the spring like element 23 behaves as a solid element the mechanism will make the elements 3 and 4 rotate slightly about the spherical bearing 5 serving as an ankle joint. This motion and the unlocking of the knee joint is beneficial in the moment in which the supporting leg has be brought forward in order for the natural gait cycle to continue. This minimal foot motion also serves the purpose to“charge“the mechanism when the user desires to climb over stairs or obstacles. When the mechanism is charged and the foot element 4 comes into contact with a solid surface the user needs to start transferring their weight to the foot elements 4 and 3 and in this way initiates a smaller standing up cycle, which cycle aids in reducing the amount of effort required by the user to climb on top of obstacles.

In order to prevent the exoskeleton from hunching over and therefore hunching over the user, when in the upright and resting position the user must exert a minimal effort to rest against the back rest 15 or the exoskeleton must have attached cargo to the quick attachment points 32 which will serve as a counter weight.