Prosthetic foot with enhanced stability and elastic energy return

1. A prosthetic foot comprising:

an attachment member comprising a connector configured to connect the attachment member to a user or another prosthetic device; and

two or more flexible members directly attached to each other along a foot portion of the prosthetic foot and separately connected to the attachment member by independent rotatable connections such that both rotation of the flexible members relative to the attachment member and flexion of the flexible members' shape can be caused by contact between the prosthetic foot and the ground, independent of other forces, wherein at least one of the flexible members continuously extends rearwardly from a proximal end of the at least one of the flexible members to a rearward position away from a toe region, where the at least one of the flexible members curves back and then continues continuously, extending forwardly from that rearward position to a distal end,

wherein the proximal end of the at least one of the flexible members is directly connected to the attachment member.

2. The prosthetic foot of claim 1 , wherein at least one of the flexible members connects to the attachment member via an actuator.

3. The prosthetic foot of claim 2 , wherein the actuator is a powered actuator.

4. The prosthetic foot of claim 3 , wherein the powered actuator is configured to power motion of at least one of the two or more flexible members.

5. The prosthetic foot of claim 2 , wherein the actuator is a passive actuator.

6. The prosthetic foot of claim 1 , further comprising a third flexible member, the third flexible member disposed beneath the two or more flexible members, and generally extending from a heel end to a toe end of the prosthetic foot, wherein the third flexible member has a plate-like shape.

7. The prosthetic foot of claim 1 , wherein the proximal end of the at least one of the flexible members is connected to the attachment member below the connector.

8. A prosthetic foot comprising:

an attachment member disposed at an ankle position of the prosthetic foot, the attachment member comprising a connector configured to connect the attachment member to a user or another prosthetic device;

an actuator coupled to an anterior portion of the attachment member by a first rotatable connection at a first end of the actuator;

a first flexible member coupled to the attachment member by a second rotatable connection and extending forward toward a toe portion of the prosthetic foot, the second rotatable connection positioned posterior of the first rotatable connection and connects to a proximal end of the first flexible member;

a second flexible member coupled to a second end of the actuator by a third rotatable connection that is positioned anterior of and above the second rotatable connection and connects to a proximal end of the second flexible member; and

a third flexible member disposed below the second flexible member to contact a ground surface while the prosthetic foot is in use, wherein posterior portions of the second and third flexible members define a gap that expands toward a rearward portion away from a toe region when in a standing position, and wherein the third flexible member has a plate-like shape.

9. The prosthetic foot of claim 8 , wherein the actuator comprises a powered actuator.

10. The prosthetic foot of claim 8 , wherein the third flexible member generally extends from a heel end and terminates posterior to a toe portion of the prosthetic foot.

11. The prosthetic foot of claim 8 , wherein the first flexible member extends rearwardly from a proximal end and then forwardly to the distal end of the first flexible member.

12. The prosthetic foot of claim 8 , wherein the third flexible member is disposed below the second flexible member along the entire length of the third flexible member.

13. The prosthetic foot of claim 8 , wherein the second rotatable connection is positioned below the connector.

14. A prosthetic foot comprising:

an attachment member disposed at an ankle position of the prosthetic foot, the attachment member comprising a connector configured to connect the attachment member to a user or another prosthetic device and first and second connection portions, the first connection portion positioned at an anterior portion of the attachment member and the second connection portion positioned at a posterior portion of the attachment member;

an actuator coupled to the first connection portion by a first rotatable connection at a first end of the actuator;

a first flexible member coupled to a second end of the actuator by a second rotatable connection and extending forward toward a toe portion of the prosthetic foot, the second end of the actuator positioned above the first end of the actuator; and

a second flexible member coupled to the second connection portion by a rotatable connection.

15. The prosthetic foot of claim 14 , wherein the actuator comprises a powered actuator.

16. The prosthetic foot of claim 14 , further comprising a third flexible member disposed below the second flexible member to contact a ground surface while the prosthetic foot is in use, wherein posterior portions of the second and third flexible members define a gap that expands toward a rearward portion away from a toe region when in a standing position.

17. The prosthetic foot of claim 16 , wherein the third flexible member generally extends from a heel end and terminates posterior to a toe portion of the prosthetic foot.

18. The prosthetic foot of claim 16 , wherein the third flexible member is disposed below the second flexible member along the entire length of the third flexible member.

19. The prosthetic foot of claim 14 , wherein the first flexible member extends rearwardly from a proximal end and then forwardly to the distal end of the prosthetic foot.

20. The prosthetic foot of claim 14 , wherein the second connection portion is positioned below the connector.