WO2021045696A1

WO2021045696A1 - Wearable lower-body support with gravity compensation mechanism

Info

Publication number: WO2021045696A1
Application number: PCT/TH2019/000038
Authority: WO
Inventors: Krittanai SAJJAPONGSE; Kawin LARPPICHET; Adithep XU
Original assignee: Astride Bionics Company Limited
Priority date: 2019-09-02
Filing date: 2019-09-02
Publication date: 2021-03-11

Abstract

A wearable lower-body support with gravity compensation mechanism comprises an upper leg (1) and a lower leg (2) which are connected to each other by a cam (3) to be a rotational joint in providing an adjustment of knee bending level as specified, wherein the cam (3) is hooked to a spring (5) and a chain (19) by a gravity compensation mechanism which works by using calculation based on the law of conservation of energy and geometric calculation in order to allow the gravity compensation mechanism that works with the apparatus, especially the spring (5) and the cam (3) for forcing and controlling user's load bearing via the gravity compensation mechanism and a one-way damping mechanism (25), to compensate for the force from knee bending or squatting by a resistance of active force from the motion and to reduce fatigue when staying in knee bending or squatting position for a long period.

Description

WEARABLE LOWER-BODY SUPPORT WITH GRAVITY COMPENSATION MECHANISM

Field of the invention

The invention relates to the field of engineering in relation to a wearable lower-body support with gravity compensation mechanism.

Background of the invention

Nowadays there is a development of strength enhancement or compensation device to help facilitate and reduce effort from changes of wearer’s movement, e.g. knee bending, sitting, squatting, bending, and turning up, wherein the strength enhancement device often uses actuator such as pneumatic or hydraulic device or electrical system control which comprises of a motor, a sensor, and a battery or any other relevant device, wherein the use of the aforementioned actuator might result in high cost and heavy weight of device or invention comprising the device that leads to high cost of production and maintenance as well as causing trouble in transportation or relocation of the device due to the heavy weight of enhancement device with said actuator.

The spring driven mechanism often causes reflection problem by sending a spring cumulative force back to user immediately when there are changes of movement from knee bending or squatting to standing position that might cause imbalance of user body which is severely harmful for user. In addition, the spring driven mechanism is passive which generates a resistant force when user moves while using the device and might cause trouble when walking or walking up the stairs.

In patent database, there are several kinds of invention in relation to a strength enhancement or compensation device based on inventors’ purposes which are detailed as follows:

According to US patent publication no. US20130245512A1 of the invention titled “Locomotion Assisting Device and Method”, it mentions a device and method for controlling an exoskeleton bracing system to help the disabled with walking and walking up the stairs in order to actuate leg joints to stretch and move the leg, wherein said device comprises of a trunk support, a leg, and joints of the disabled, wherein the joints are assembled with the device to define a relative angular movement along with sensors to detect a force between the ground and the leg and provide algorithm processing to define a posture based on detected signals and defined posture to actuate motorized joints.

According to US patent publication no. US20150321340A1 of the invention titled “Legged Robotic Device Utilizing Modifiable Linkage Mechanism”, it mentions a dynamic legged robotic device for assembling with the lower part of the body which comprises of a primary actuator for actuating driven mechanism, wherein said actuator can be controlled by a force or a torque to ensure leg control.

A comparison of the present invention and a mechanism of other lower-limb exoskeleton suits found that the mechanism of other existing inventions utilizes a gravity compensation mechanism with an actuator to carry a load or continually generate a resistance force for user, and a comparison of the present invention and the spring driven mechanism founds that the spring consistently generates a resistance force when user moves as well as sending a spring cumulative force back to user immediately when there are changes of movement from squatting to stand-up position which might cause an imbalance of user body. As for a lander of other lower-limb exoskeleton suits which comprise of a foot frame to hold lower leg components with user, in comparison with a lander separating freely from user’s foot frame, it is found that said lander often causes imbalance of user body and might not be able to provide movement control conveniently and efficiently while using.

Due to the aforementioned problems, the inventor develops a gravity compensation mechanism to consistently and continually support changes of user movement without using an actuator which results in a lightweight wearable lower-body support with gravity compensation mechanism, causing more convenient movement. In addition, the present invention comprises of a mode changer mechanism between free mode and gravity compensation mode for user to be able to make an adjustment in accordance with preferable movement and to allow user to move steadily and smoothly, moving continually without discontinuation.

Summary of the invention

A wearable lower-body support with gravity compensation mechanism comprises of an upper leg and a lower leg which are connected to each other by a cam to be a pivot joint in an adjustment of specified knee bending degree, wherein the cam is hooked to a spring and a chain with gravity compensation mechanism which utilizes the law of conservation of energy and geometric calculation in order for the gravity compensation mechanism that works with the device, especially with the spring and the cam, to force and control user’s load bearing via the gravity compensation mechanism and damping mechanism to compensate a force from knee bending or squatting by a resistance of active force caused by said movement and to reduce fatigue when staying in knee bending or squatting position for a long time.

The objective of the present invention is to develop a gravity compensation mechanism for consistently and continually supporting changes of user movement without using an actuator which results in a lightweight wearable lower-body support with gravity compensation mechanism, causing more convenient movement. In addition, the present invention comprises of a mode changer mechanism between free mode and gravity compensation mode for user to be able to make an adjustment in accordance with preferable movement and to allow user to move steadily and smoothly, moving continually without discontinuation as well as providing the invention for freely separating lander from user’s foot frame.

Brief description of the drawings

Figure 1 illustrates one embodiment of a wearable lower-body support with gravity compensation mechanism.

Figure 2 illustrates one embodiment of a wearable lower-body support with gravity compensation mechanism.

Figure 3 illustrates one embodiment of a gravity compensation mechanism when user bends the knees.

Figure 4 illustrates one embodiment of a gravity compensation mechanism when user stands in a free mode.

Figure 5 illustrates one embodiment of a gravity compensation mechanism in a gravity compensation mode.

Figure 6 illustrates one embodiment of a lock.

Figure 7 illustrates one embodiment of a one-way damping mechanism in a regular condition.

Figure 8 illustrates one embodiment of a one-way damping mechanism when receiving an active force.

Figure 9 illustrates one embodiment of lower leg components. Detailed description of the invention

Figure 1 and 2 illustrate one embodiment of a wearable lower-body support with gravity compensation mechanism, wherein the wearable lower-body support with gravity compensation mechanism comprises of an upper leg 1 and a lower leg 2 which are connected to each other by a cam 3 to be a pivot joint in adjusting knee bending degree, wherein said cam 3 is hooked to a chain 19.

In one embodiment of the driving of a chain 19 to a cam 3, the cam 3 comprises of teeth which mesh the holes in the chain 19 to pull a shaft 4 and a spring 5 to be compressed or released in accordance with the user’s weight and the angle of the knee working jointly with a one-way damping mechanism (25) in order to compensate a force from knee bending, kneeling or squatting by a resistance of active force from said movement and to reduce fatigue when staying in knee bending, kneeling or squatting position for a long time.

The gravity compensation mechanism of the present invention works by utilizing the law of conservation of energy and geometric calculation to allow the mechanism to work with the device, especially the spring 5 and the cam 3 wherein the upper leg 1 and the lower leg 2 are assembled with an attachment which attaches user’s hips and legs to the wearable lower-body support with gravity compensation mechanism according to the present invention. Preferably, the top part of the upper leg 1 is assembled with a hip or upper-thigh attachment, and the lower leg 2 is assembled with a leg, calf or below-the-knee attachment wherein the upper leg 1 is assembled with a chain tensioner 15 which is installed at the top part of gravity compensation mechanism to receive and drive the chain 19 of the present invention, and the gravity compensation mechanism is assembled with one-way damping mechanism (25) which is preferably installed at the top part and lower part of the gravity compensation mechanism for receiving force and controlling the gravity compensation mechanism which comprises of any one or more of a chain 19, a shaft 4, and a spring 5 assembled together for driving and supporting force from user when bending the knees, squatting or standing, and the lower leg 2 comprises of an adjustable length toggle which allows for length adjustment using the rail of the lower leg (2).

Figure 3 illustrates one embodiment of a gravity compensation mechanism when user bends the knees and figure 4 illustrates one embodiment of a gravity compensation mechanism when user stands in a free mode, wherein one embodiment of the mechanism of the gravity compensation mechanism, when user tries to bend the knees or squat, causes the upper leg 1 and lower leg 2 to change the angle following user’s knee bending degree, wherein the cam 3 is provided to pull the chain 19 down along the knee bending degree, wherein said chain 19 is connected to a shaft 4 which comprises of a spring 5 for controlling a degree of the release of the spring 5 which results in, when the shaft 4 is pulled down by the chain 19 along the knee bending degree, the spring 5 is pushed by a spring support 16 until it is compressed and it will be released when user stands up or turning to the previous position, wherein when user stands up, the one-way damping mechanism 25 will help disperse the force from a reflection of the spring 5 and that helps provide more smooth movement.

Figure 5 illustrates one embodiment of a gravity compensation mechanism in a gravity compensation mode and figure 6 illustrates one embodiment of a locker, wherein the lower leg 2 comprises of a free mode changer mechanism in order for user to walk or move without gravity compensation, and the gravity compensation mode in case user would like to stay in knee bending, squatting or kneeling position wherein both mechanisms are controlled by the lock 6 which engages or disengages the gravity compensation mechanism which helps user select the mode of the present invention in accordance with preferred movement or position For example, if user would like to walk up the stairs, turning on the free mode makes the gravity compensation mechanism stop working in order that user walks or move conveniently without gravity compensation, without damping or friction of the mechanism which is not suitable for some positions that require continual movement.

The lock 6 works with the chain 19 for locking or unlocking rotation of the cam 3 when there is knee bending while walking or walking up the stairs, wherein said lock 6 comprises of any one or more of a body 26, a latch 27, a locking slot 28, a screw hole 29 assembled together, wherein the body 26 comprises of a latch 27 which slides along the rail of the body 26, wherein the latch 27 comprises of the locking slot for assembling with teeth for sliding along the rail to lock by pushing the latch 27 to make it attach with the holes in the chain 19, locking the chain 19 from moving. As for the use of gravity compensation mode or unlocking, slide the teeth to make the latch 27 move back to the body 26 as it was and then the chain 19 can move for free mode using. The use of spring 5 driven mechanism often causes reflection problem by sending back a spring cumulative force to user immediately when there are changes of movement from squatting to standing position that might cause imbalance of user body which is severely harmful for user. Hence, it is needed to invent a one-way damping mechanism 25 to compensate user’s weight in knee bending or squatting position which will disperse the force back when user changes from knee bending or squatting to standing up or standing position, wherein said mechanism will help provide damping of restoring degree of the spring 5, making the spring 5 gradually stretch out smoothly, especially when user changes movement from knee bending or squatting to standing up or standing or from knee bending back to a normal stand.

According to figure 7, it illustrates one embodiment of one-way damping mechanism in a regular condition, and figure 8 illustrates one embodiment of one-way damping mechanism when receiving active force, wherein a gravity compensation mechanism is connected to a braking rail 13 of one-way damping mechanism 25, wherein the one-way damping mechanism 25 comprises of any one or more of a base 11, a wedge 14, a spring 12, and a braking rail 13 assembled together to retard a reversion degree of the spring 5, causing the spring 5 stretch out smoothly or not causing an abrupt spring flip wherein the braking rail 13 is a connection to the gravity compensation mechanism and the base 11 absorbs the force released by a spring. When user changes movement, a force from the spring 5 is sent to the base 11 and sent to the spring 12. Then, the spring 12 pushes the wedge 14 which contains certain frictional degree to resist sent force. Then, the wedge 14 slides along the rail and slides back to the previous condition when turning back to an initial position

One embodiment of one-way damping mechanism 25, according to figure 7, illustrates one embodiment of friction damping mechanism in a regular condition. When the one-way damping mechanism 25 receives an active force in a similar direction, the wedge 14 generates no resistance force.

However, in figure 8, it illustrates one embodiment of friction damping mechanism when receiving an active force. When the one-way damping mechanism 25 receives an active force in the opposite direction, the wedge 14 slides down the rail, generating a resistance force between the wedge 14 and the braking rail 13, causing a replacement of force from the spring

5. According to figure 9, it illustrates one embodiment of lower leg components, wherein the lower leg 2 comprises of any one or more of a lander 9, a spring 8, and a stopper 10 assembled together, wherein the lander 9 is installed at the latter part of the lower leg 2 to be a pivot point and a setup of the wearable lower-body support with gravity compensation mechanism according to the present invention to make it stable in knee bending or squatting position, wherein the lander 9 is assembled with the spring 8 preferably at the opposite of the pivot point between the latter part of the lower leg 2 and the lander 9 for supporting force of user’s weight and leading the force to the lander 9 gradually, allowing user to stably define knee bending or squatting degree and also increasing the stability by using with the stopper 10 which helps limit lander 9 movement, wherein the stopper is preferably installed between the lander 9 and the spring 8 to prevent improper dislocation.

In one embodiment of the use of wearable lower-body support with gravity compensation mechanism according to the present invention, when user wears the device and bends the knees or squats, the lower leg 2 and the upper leg 1 changes the angle in accordance with user’s knee bending degree by adjusting a cam 3 to make some angles between the lower leg 2 and the upper leg 1, wherein the gravity compensation mechanism which pulls down the chain 19 through the cam 3 causes a pulling down of the shaft 4 which is attached to the chain 19, resulting in a compression of the spring 5 due to a compression force between the shaft 4 and a spring support 16, affecting a generation of torque in the same shaft as the cam 3, causing a compensation torque from user’s gravity or providing a compensation of knee bending or squatting by resisting the active force of said stance and reducing force on user’s muscle and reducing fatigue when staying in knee bending or squatting position for a long time, and if user wants to stands up or stand, user can stand up without an abrupt spring 5 release.

Besides, user can adjust leg length degree by an adjustable length toggle 23 which allows for length adjustment using the rail to increase or decrease user’s leg length degree. In case user wants to walk or walk up the stairs, user can change it to a free mode, causing the gravity compensation mechanism to stop working, then user can move conveniently without the gravity compensation. If user wants to stay in knee bending or squatting position, user can change it back to a gravity compensation mode to make it change to a regular gravity compensation mechanism. Any modification can be clearly understood and can be made by those skilled in the art in this field wherein it might be under the scope and purpose of the present invention as detailed in the following claims.

Best mode of the invention The best method of invention is as described in detailed description of the invention.

Claims

1. A wearable lower-body support with gravity compensation mechanism comprises of an upper leg (1) and a lower leg (2) connected to each other by a cam (3), wherein the characteristic is that the cam (3) is hooked to a chain (19) which pulls a shaft (4) and a spring (5) to be compressed or released in accordance with the user’s weight and the angle of the knee working jointly with a one-way damping mechanism (25).

The one-way damping mechanism (25) comprises of a braking rail (13) which is connected to the gravity compensation mechanism, and a base (11) which absorbs the force released by a spring (5). The spring (12) which then pushes a wedge (14) along the rail and moves back to a regular condition when it is back to its initial position wherein the present invention also comprises of a mode changer mechanism between free mode and gravity compensation mode by a lock (6) which comprises of a body (26) and a latch (27) which slides along the rail within the body (26), wherein said latch (27) comprises of a locking slot (28) which works by pushing the latch (27) to make it attach to a groove of the chain (19), and a latter part of the lower leg (2) comprises of a lander (9) which is connected to a spring (8) and a stopper (10).

2. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the cam (3) comprises of the teeth which mesh with the holes in the chain

(19);

3. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the upper leg (1) and the lower leg (2) are assembled with an attachment which attaches to hips and legs;

4. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the gravity compensation mechanism is assembled with a one-way damping mechanism (25) which is preferably installed at the top and bottom part of the gravity compensation mechanism;

5. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the lower leg (2) comprises of an adjustable length toggle (23) which allows for length adjustment using the rail of the lower leg (2);

6. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the stopper (10) is preferably installed at the opposite of a pivot point between the latter part of the lower leg (2) and the lander (9);

7. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the upper leg (1) is assembled with a chain tensioner (15) which is installed at the upper part of the gravity compensation mechanism;

8. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the lock (6) comprises of any one or more of the following parts; a body (26), a latch (27), a locking slot (28), and a screw hole (29) assembled together;

9. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the gravity compensation mechanism comprises of any one or more of the following parts; a chain (19), a shaft (4), a chain tensioner (15) and a spring (5) assembled together;

10. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the one-way damping mechanism (25) comprises any one or more of following parts; abase (11), a wedge (14), a spring (12), and a braking rail (13);

11. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the upper leg (1) is preferably assembled with a hip or upper-thigh attachment;

12. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the lower leg (2) is preferably assembled with a leg, calf or below-the- knee attachment;

13. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the lower leg (2) is rotatable in accordance with a range specification of the cam (3);

14. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the lower leg (2) is foldable and the lower leg (2) is attachable to the upper leg (i);

15. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the spring (5) is clamped by a spring support (16);

16. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the lock (6) engage or disengage the gravity compensation mechanism;

17. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the latch (27) comprises a locking slot (28) which is assembled with the protrusion to make it slide along the rail;

18. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the base (11) absorbs force caused by the release of the spring (5) when user changes posture;

19. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the one-way damping mechanism (25) receives an active force in the same direction, causing the wedge (14) to generate no friction;

20. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the one-way damping mechanism (25) receives an active force in the opposite direction, causing the wedge (14) to slide down the rail, creating friction between the wedge (14) and the beam (13) which results in that the force received from the spring

(5) is replaced and compensate for the spring (5) release;

21. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the lander (9) is installed at the bottom part of the lower leg (2);

22. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the lander (9) is joined with the spring (8);

23. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the stopper (10) limits the movement of the lander (9);

24. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the stopper (10) is installed between the lander (9) and the spring (8);

25. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the free mode is the mode by which the gravity compensation mechanism stops working; and,

26. The wearable lower-body support with gravity compensation mechanism according to claim 1 wherein the gravity compensation mechanism uses calculation based on the law of conservation of energy and geometric calculation.