Ankle block with spring inserts

• US 6,206,934 B1
• Filed: 08/21/1998
• Issued: 03/27/2001
• Est. Priority Date: 04/10/1998
• Status: Expired due to Term

• Current Assignee: Flex Foot Inc. (Ossur hf)
• Original Assignee: Flex Foot Inc. (Ossur hf)
• Inventors: Phillips, Van L.
• Primary Examiner(s): Willse, David H.
• Assistant Examiner(s): Jackson, Suzette J.
• Application Number:
  US09/138,357
• Time in Patent Office: 949 Days
• Field of Search: 623/47-55
• US Class Current: 623/53
• CPC Class Codes: A61F 2/602 with air cushions A61F2/7843 takes precedence
• CPC Class Codes: A61F 2/66 Feet; Ankle joints
• CPC Class Codes: A61F 2/6607 Ankle joints
• CPC Class Codes: A61F 2/68 Operating or control means
• CPC Class Codes: A61F 2/74 fluid , i.e. hydraulic or pneumatic
• CPC Class Codes: A61F 2/741 using powered actuators, e.g. stepper motors or solenoids
• CPC Class Codes: A61F 2/748 Valve systems
• CPC Class Codes: A61F 2002/5001 Cosmetic coverings
• CPC Class Codes: A61F 2002/5007 having elastic means different from springs, e.g. including an elastomeric insert elastic coating A61F2002/3007; springs A61F2002/5072; plate-like springs for feet A61F2002/6657
• CPC Class Codes: A61F 2002/501 having an inflatable pocket filled with fluid, i.e. liquid or gas
• CPC Class Codes: A61F 2002/5012 having two or more inflatable pockets
• CPC Class Codes: A61F 2002/503 for adjusting elasticity, flexibility, spring rate or mechanical tension
• CPC Class Codes: A61F 2002/5033 for adjusting damping damping means A61F2002/5003
• CPC Class Codes: A61F 2002/5055 Reinforcing prostheses by embedding particles or fibres during moulding or dipping, e.g. carbon fibre composites
• CPC Class Codes: A61F 2002/6614 Feet
• CPC Class Codes: A61F 2002/6657 having a plate-like or strip-like spring element, e.g. an energy-storing cantilever spring keel
• CPC Class Codes: A61F 2002/6678 L-shaped
• CPC Class Codes: A61F 2002/701 operated by electrically controlled means, e.g. solenoids or torque motors

Abstract

Provided herein is a simple, inexpensive prosthetic foot incorporating an ankle block with spring inserts. The ankle block is formed of compressible material having desired compliance and energy return characteristics. The ankle block is sandwiched between a foot element and an ankle element. One or more spring inserts are embedded inside the ankle block to increase the rigidity of the prosthetic foot and to improve the degree of energy storage and return. The shape of the spring inserts is preferably one that supports compression during relative angular rotation of the ankle plate and foot plate elements, such as during toe and heel roll, and also vertical compression, such as in response to vertical shock loads.

Claims

1. A prosthetic foot for attaching to a socket or pylon of a lower-limb amputee, comprising:

a foot plate element having a length approximately equal to the length of a human foot, the foot plate element comprising a resilient material capable of flexing along its length;

an ankle plate element having a length substantially shorter than the foot plate element;

an ankle block comprising a relatively soft, compressible material sandwiched between the ankle plate element and the foot plate element, the ankle block providing energy storage and support and connection between the foot plate element and the ankle plate element; and

a spring element embedded within the ankle block for providing additional energy storage and support, said spring element having a posterior portion configured to compress during heel-strike, and an anterior portion configured to compress during toe-off;

whereby the foot plate element, the ankle block, and the spring element flex in a cooperative manner to provide substantially smooth and continuous rollover transition from heel-strike to toe-off.

2. The prosthetic foot of claim 1, wherein the foot plate element has a tapered thickness along its length, such that the thickness increases from a heel section to an arch section and decreases from the arch section to a toe section.

3. The prosthetic foot of claim 2, wherein the heel and toe sections are formed substantially concave-up and the arch section is formed substantially concave-down.

4. The prosthetic foot of claim 1, wherein the ankle block has a substantially planar upper surface and a curvilinear lower surface, the upper surface mating with a bottom surface of the ankle plate element, the lower surface mating with a top surface of the foot plate element.

5. The prosthetic foot of claim 1, wherein the ankle plate element, the ankle block and the spring element are centered transversely with respect to and are generally positioned over a back half of the foot plate element.

6. The prosthetic foot of claim 1, wherein the ankle block is made of a foam block having a density between about 150 and 1500 kg/m³.

7. The prosthetic foot of claim 1, wherein the spring element is formed from a carbon fiber composite material.

8. The prosthetic foot of claim 1, wherein the spring element comprises upper and lower relatively flat members secured at their center by a fastener and separated at their ends.

9. The prosthetic foot of claim 8, wherein the upper member is substantially curvilinear concave upward and the lower member is substantially curvilinear concave downward.

10. The prosthetic foot of claim 1, further comprising at least one opening extending through the ankle block adapted to receive a stiffener for adjusting the spring characteristics of the prosthetic foot.

11. The prosthetic foot of claim 10, wherein a first and second cylindrical opening extend through the ankle block, the first opening being positioned in a fore portion of the block and the second opening being positioned in a rear portion of the block.

12. The prosthetic foot of claim 11, wherein tubular stiffeners are placed in the openings.

13. A prosthetic foot, comprising:

an upper plate;

a lower plate;

a compressible layer formed of a compressible material, said compressible material connected to the upper plate and the lower plate and separating the upper plate from the lower plate; and

a spring element made of resilient material embedded within the compressible layer and spaced apart from the upper and lower plates, said spring element configured to store and release walking energy during ambulation of said prosthetic foot.

14. The prosthetic foot of claim 13, wherein the lower plate has a length and a width roughly equal to the approximate length and width of an amputated foot.

15. The prosthetic foot of claim 13, wherein the upper plate and the compressible layer have approximately the same cross-sectional size.

16. The prosthetic foot of claim 13, wherein the compressible layer is made of a foam material having a density between about 150 and 1500 kg/m³.

17. The prosthetic foot of claim 13, wherein the spring element is made of a carbon fiber material.

18. The prosthetic foot of claim 13, wherein the spring element has a substantially double wishbone shape.

19. The prosthetic foot of claim 13, wherein the spring element is a plate-like member with a curvilinear concave downward shape.

20. The prosthetic foot of claim 13, wherein the spring element is a foam material having a density between about 150 and 1500 kg/m³.

21. The prosthetic foot of claim 13, wherein the spring element is a tubular member inserted into the compressible layer.

22. A prosthetic foot including a resilient ankle block for separably mounting between a foot plate and an ankle plate of a prosthetic foot for providing resilient kinematic support to an amputee relative to a ground surface, the ankle block comprising a block of resilient material and at least one spring insert embedded within the block of resilient material, said spring insert configured to store and release walking energy during ambulation of said prosthetic foot, said ankle block being substantially the sole means of connection and support between said foot plate and said ankle plate.

23. The prosthetic foot of claim 22, wherein the block of resilient material is an expanded polyurethane having a density between about 150 and 1500 kg/M³.

24. The prosthetic foot of claim 23, wherein the expanded polyurethane has a density of about 500 kg/m³.

25. The prosthetic foot of claim 22, wherein a first spring insert comprises upper and lower substantially plate-like members joined at their center and separated at their ends, the upper member being substantially curvilinear concave upward and the lower member being substantially curvilinear concave downward.

26. The prosthetic foot of claim 25, wherein the first spring insert is made of a carbon fiber composite material.

27. The prosthetic foot of claim 25, wherein a second spring insert comprises at least one tubular stiffener.

28. The prosthetic foot of claim 27, wherein a first tubular stiffener is positioned in a fore region of the ankle block between the upper and lower substantially plate-like members, and a second tubular stiffener is positioned in an aft region of the ankle block between the upper and lower substantially plate-like members.

29. The prosthetic foot of claim 28, wherein the first and second tubular stiffeners are made of an expanded polyurethane having a density between about 150 and 1500 kg/m³.

30. The prosthetic foot of claim 29, wherein the first and second tubular stiffeners are made of an expanded polyurethane having a density of between about 250 and 750 kg/m³.

31. The prosthetic foot of claim 22, wherein the at least one spring element is a plate-like member having a substantially curvilinear downward shape.

32. A prosthetic foot, comprising:

a support plate made of a resilient material and having a length approximately equal to the length of a human foot;

a layer of compressible material mounted to the support plate; and

a spring element comprising at least one substantially plate-like member embedded within the layer of compressible material, said plate-like member configured to store and release walking energy.

33. The prosthetic foot of claim 32, wherein the layer of compressible material is foam.

34. The prosthetic foot of claim 32, wherein the spring element is made of a carbon fiber material.

35. The prosthetic foot of claim 32, wherein the spring element comprises a pair of substantially plate-like members, the plate-like members being secured at their center and separated at their ends.

36. The prosthetic foot of claim 32, wherein the at least one substantially plate-like member has a curvilinear concave downward shape.

37. A prosthetic foot for attaching to a socket or pylon of a lower-limb amputee, comprising:

a foot plate element having a length approximately equal to the length of a human foot, the foot plate element comprising a resilient material capable of flexing along its length;

an ankle plate element having a length substantially shorter than the foot plate element;

an ankle block comprising a relatively soft, compressible material sandwiched between the ankle plate element and the foot plate element, the ankle block providing energy storage and support and connection between the foot plate element and the ankle plate element; and

a spring element embedded within the ankle block for providing additional energy storage and support, said spring element being formed from a carbon fiber composite material;

whereby the foot plate element, the ankle block, and the spring element flex in a cooperative manner to provide substantially smooth and continuous rollover transition from heel-strike to toe-off.

38. A prosthetic foot for attaching to a socket or pylon of a lower-limb amputee, comprising:

a foot plate element having a length approximately equal to the length of a human foot, the foot plate element comprising a resilient material capable of flexing along its length;

an ankle plate element having a length substantially shorter than the foot plate element;

an ankle block comprising a relatively soft, compressible material sandwiched between the ankle plate element and the foot plate element, the ankle block providing energy storage and support and connection between the foot plate element and the ankle plate element; and

a spring element embedded within the ankle block for providing additional energy storage and support, said spring element comprising upper and lower relatively flat members secured at their center by a fastener and separated at their ends;

whereby the foot plate element, the ankle block, and the spring element flex in a cooperative manner to provide substantially smooth and continuous rollover transition from heel-strike to toe-off.

39. The prosthetic foot of claim 38, wherein the upper member is substantially curvilinear concave upward and the lower member is substantially curvilinear concave downward.

40. A prosthetic foot, comprising:

an upper plate;

a lower plate;

a compressible layer connected to the upper plate and the lower plate and separating the upper plate from the lower plate; and

a spring element made of resilient material embedded within the compressible layer and spaced apart from the upper and lower plates, said spring element being made of a carbon fiber material.

41. A prosthetic foot, comprising:

an upper plate;

a lower plate;

a compressible layer connected to the upper plate and the lower plate and separating the upper plate from the lower plate; and

a spring element made of resilient material embedded within the compressible layer and spaced apart from the upper and lower plates, said spring element having a substantially double wishbone shape.

42. A prosthetic foot, comprising:

an upper plate;

a lower plate;

a compressible layer connected to the upper plate and the lower plate and separating the upper plate from the lower plate; and

an energy storing spring element made of resilient material embedded within the compressible layer and spaced apart from the upper and lower plates, said spring element comprising a plate-like member with a curvilinear concave downward shape.

43. A prosthetic foot including a resilient ankle block for separably mounting between a foot plate and an ankle plate of a prosthetic foot for providing resilient kinematic support to an amputee relative to a ground surface, the ankle block comprising a block of resilient material and at least one spring insert embedded within the block of resilient material, wherein a first spring insert comprises upper and lower substantially plate-like members joined at their center and separated at their ends, the upper member being substantially curvilinear concave upward and the lower member being substantially curvilinear concave downward.

44. The prosthetic foot of claim 43, wherein the first spring insert is made of a carbon fiber composite material.

45. The prosthetic foot of claim 43, wherein a second spring insert comprises at least one tubular stiffener.

46. The prosthetic foot of claim 45, wherein a first tubular stiffener is positioned in a fore region of the ankle block between the upper and lower substantially plate-like members, and a second tubular stiffener is positioned in an aft region of the ankle block between the upper and lower substantially plate-like members.

47. The prosthetic foot of claim 46, wherein the first and second tubular stiffeners are made of an expanded polyurethane having a density between about 150 and 1500 kg/m³.

48. The prosthetic foot of claim 47, wherein the first and second tubular stiffeners are made of an expanded polyurethane having a density of between about 250 and 750 kg/m³.

49. A prosthetic foot including a resilient ankle block for separably mounting between a foot plate and an ankle plate of a prosthetic foot for providing resilient kinematic support to an amputee relative to a ground surface, the ankle block comprising a block of resilient material and at least one energy storing spring insert embedded within the block of resilient material, wherein the at least one spring insert is a plate-like member having a substantially curvilinear downward shape.

50. A prosthetic foot, comprising:

a support plate made of a resilient material and having a length approximately equal to the length of a human foot;

a layer of compressible material mounted to the support plate; and

a spring element comprising at least one substantially plate-like member embedded within the layer of compressible material, said spring element being made of a carbon fiber material.

51. A prosthetic foot, comprising:

a support plate made of a resilient material and having a length approximately equal to the length of a human foot;

a layer of compressible material mounted to the support plate; and

a spring element comprising a pair of substantially plate-like members being secured at their center and separated at their ends, at least one of said plate-like members being embedded within the layer of compressible material.

52. A prosthetic foot, comprising:

a support plate made of a resilient material and having a length approximately equal to the length of a human foot;

a layer of compressible material mounted to the support plate; and

a spring element comprising at least one substantially plate-like member embedded within the layer of compressible material and having a curvilinear concave downward shape.