Apparatus and clutch for using controlled storage and release of mechanical energy to aid locomotion
The subject matter described herein includes an apparatus and a clutch for using controlled storage and release of mechanical energy to aid in locomotion. One exemplary apparatus includes a frame including an upper portion configured to mechanically couple to a leg of the subject on a calf side of an ankle joint of the subject and a lower portion pivotally attached to the upper portion configured to mechanically couple to a foot of the subject on a foot side of the ankle joint of the subject. The apparatus include a rotary clutch and an elastic element coupled between the upper and lower portions of the frame to control periods of energy storage and release by the elastic element.
1. An apparatus for using controlled storage and release of mechanical energy to aid in locomotion, the apparatus comprising:
a frame including an upper portion configured to mechanically couple to a leg of a subject on a calf side of an ankle joint of the subject and a lower portion pivotally attached to the upper portion configured to mechanically couple to a foot of the subject on a foot side of the ankle joint of the subject; and
a rotary clutch and an elastic element coupled between the upper and lower portions of the frame to control periods of energy storage and release by the elastic element, wherein the rotary clutch includes a rotatable drum, a ratchet coupled to the rotatable drum, a pawl, and first and second structures located on the rotatable drum to selectively engage and disengage the pawl from the ratchet.
2. The apparatus of claim 1 , wherein the upper portion of the frame is configured to fit around at least a portion of the calf of the subject and wherein the lower portion is configured to surround at least a portion of the foot of the subject.
3. The apparatus of claim 2 , wherein the upper and lower portions are coupled to each other via hinges that allow dorsiflexion and plantar flexion of the ankle joint of the subject.
4. The apparatus of claim 2 , wherein the lower portion of the frame comprises a shoe.
5. The apparatus of claim 2 , wherein the lower portion of the frame is configured to attach to a shoe.
6. The apparatus of claim 1 , wherein the clutch is coupled to the upper portion of the frame and the elastic element is coupled to the lower portion and to the clutch.
7. The apparatus of claim 1 , wherein the elastic element is coupled to the clutch via a linkage that is less resilient than the elastic element in a direction of intended application of force to the elastic element.
8. The apparatus of claim 7 , wherein the linkage comprises a cord that is coupled to the drum such that rotation of the drum extends and retracts the cord.
9. The apparatus of claim 1 , wherein the elastic element comprises a coil spring or an elongate elastomeric member that stretches in a direction of applied force.
10. The apparatus of claim 1 , wherein the elastic element comprises a resilient material that bends in a direction of applied force.
11. The apparatus of claim 1 , wherein the clutch is configured to engage before heel strike of the individual's foot, to lock during a foot flat position of the individual's foot such that the elastic element stores mechanical energy during dorsiflexion of the ankle joint and releases the stored energy during push off of the individual's foot, and wherein the clutch is configured to release during or after the push off to allow free rotation of the ankle joint during foot swing of the individual's foot.
12. The apparatus of claim 1 , wherein the pawl includes a structure having a first side facing a first direction and a second side facing a second direction different from the first direction and the clutch includes a detent mechanism for engaging the pawl on the first side or the second side for holding the pawl in engagement with or away from the ratchet.
13. The apparatus of claim 1 , wherein the clutch is configured to engage, lock, and disengage in response to a biological signal from the subject.
14. The apparatus of claim 13 , wherein the biological signal comprises an electromyography signal.
15. The apparatus of claim 1 , wherein the periods of energy storage and release controlled by the clutch are adjustable according to a gait of the individual.
16. The apparatus of claim 1 , wherein the first and second structures include a first timing pin for engaging the ratchet with the pawl and a second timing pin for releasing the ratchet from the pawl.
17. The apparatus of claim 16 , wherein positions of the timing pins are adjustable to change the periods of energy storage and release.
18. The apparatus of claim 1 , wherein the frame comprises an exoskeleton.
19. The apparatus of claim 1 , wherein the frame, clutch, and elastic member form an ankle foot orthotic (AFO) device.