Swing phase control for an artificial lower limb

• US 6,613,097 B1
• Filed: 05/26/2000
• Issued: 09/02/2003
• Est. Priority Date: 06/28/1999
• Status: Expired due to Fees

• Current Assignee: Ohio Willow Wood Company
• Original Assignee: Ohio Willow Wood Company
• Inventors: Cooper, John Edwin
• Primary Examiner(s): McDermott, Corrine
• Assistant Examiner(s): STEWART, ALVIN J
• Application Number:
  US09/579,437
• Time in Patent Office: 1,194 Days
• Field of Search: 623/44, 623/45, 623/43, 623/46, 623/39, 623/26, 188/285, 188/322.19, 188/282.3, 188/282.2, 188/314
• US Class Current: 623/44
• 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 2/80 Sockets, e.g. of suction type
• CPC Class Codes: A61F 2002/5032 for adjusting fluid pressure

Abstract

A hydraulic swing phase control unit for an artificial lower limb including a thigh part and a shin part connected at a knee joint, includes a hydraulic cylinder connected to one of the thigh part and the shin part, a piston movable in the hydraulic cylinder and connected to the other of the thigh part and the shin part, a fluid passage positioned to pass hydraulic fluid pressurized by movement of the piston in the hydraulic cylinder; and a variable sharp edged orifice at the fluid passage. The variable orifice is formed from a sharp edged orifice and a manually rotatable sleeve positioned to at least partly overlap the orifice. At least one low restriction fluid passage in the cylinder is fluidically connected in parallel with the variable sharp edged orifice to permit minimal resistance to movement of the piston during a portion of the movement thereof.

Claims

1. A hydraulic swing phase control unit for an artificial lower limb, comprising:

means for providing minimal resistance to shin flexion until a predetermined angle of flexion which corresponds to the toe off position is reached;

means for providing adjustable resistance to flexion after the toe off position is reached;

means for providing minimal resistance to shin extension until predetermined angle which is near to the fully extended position is reached; and

means for providing adjustable resistance to extension after the predetermined angle is reached during shin extension.

2. The hydraulic swing phase control unit of claim 1, further comprising means for providing a spring returning force at the end of shin flexion.

3. A hydraulic swing phase control unit for an artificial lower limb, comprising:

means for providing minimal resistance to shin flexion until a predetermined angle of flexion which corresponds to the toe off position is reached;

means for providing adjustable resistance to flexion after the toe off position is reached; and

means for subsequently providing minimal resistance to shin flexion when a predetermined angle which corresponds to sitting or kneeling is reached.

4. The hydraulic swing phase control unit of claim 3, further comprising:

means for providing minimal resistance to shin extension until predetermined angle which is near to the fully extended position is reached; and

means for providing adjustable resistance to extension after the predetermined angle is reached during shin extension.

5. The hydraulic swing phase control unit of claim 3, further comprising means for providing a spring returning force at the end of shin flexion.

6. A hydraulic swing phase control unit for an artificial lower limb including a thigh part and a shin part connected at a knee joint, comprising:

a hydraulic cylinder connected to one of the thigh part and the shin part;

a piston movable in said hydraulic cylinder and connected to the other of the thigh part and the shin part;

a fluid passage positioned to pass hydraulic fluid pressurized by movement of said piston in said hydraulic cylinder; and

a variable sharp edged orifice at said fluid passage, said variable sharp edged orifice providing a change in a pressure from therethrough which varies in proportion to a square of a rate of flow of fluid therethrough.

7. The hydraulic swing phase control unit of claim 6, wherein said variable orifice comprises:

a sharp edged orifice at said fluid passage; and

a manually rotatable sleeve positioned to at least partly overlap said orifice.

8. The hydraulic swing phase control unit of claim 6, further comprising at least one low restriction fluid passage in said cylinder, said low restriction fluid passage being fluidically connected in parallel with said variable sharp edged orifice, to permit minimal resistance to movement of said piston during a portion of the movement thereof.

9. The hydraulic swing phase control unit of claim 8, further comprising a fluid passage in said piston and in fluid communication with said low restriction fluid passage during a portion of the movement of said piston.

10. The hydraulic swing phase control unit of claim 6, wherein the unit is connected to the thigh part and the shin part such that an effective line of action of the unit is anterior to the knee axis.

11. The hydraulic swing phase control unit of claim 6, wherein the unit is connected to the thigh part and the shin part such that an effective line of action of the unit is posterior to the knee axis.

12. The hydraulic swing phase control unit of claim 6, wherein there are two of said fluid passages positioned to pass hydraulic fluid pressurized by movement of said piston in said hydraulic cylinder, and one of said variable sharp edged orifices at each said fluid passage, wherein said two fluid passages are positioned to be on mutually opposite sides of said piston.

13. The hydraulic swing phase control unit of claim 6, wherein said unit'"'"'s performance is minimally sensitive to temperature changes.

14. The hydraulic swing phase control unit of claim 6, wherein said unit'"'"'s resistance is proportional to the angular velocity of the leg.

15. A hydraulic swing phase control unit for an artificial lower limb, comprising:

means for providing minimal resistance to shin flexion until a predetermined angle of flexion which corresponds to the toe off position is reached;

means for providing increased resistance to flexion after the toe off position is reached; and

means for subsequently providing minimal resistance to shin flexion.

16. The hydraulic swing phase control unit of claim 15, wherein said means for providing increased resistance to flexion after the toe off position is reached, comprises means for providing variable resistance to flexion after the toe off position is reached.

17. A hydraulic swing phase control unit for an artificial lower limb, comprising:

means for providing minimal resistance to shin flexion until a predetermined angle of flexion which corresponds to the toe off position is reached;

means for providing increased resistance to flexion after the toe off position is reached;

means for providing minimal resistance to shin extension until a predetermined angle which is near to the fully extended position is reached; and

means for providing increased resistance to extension after the predetermined angle is reached during shin extension.

18. The hydraulic swing phase control unit of claim 17, wherein said means for providing increased resistance to flexion after the toe off position is reached, comprises means for providing variable resistance to flexion after the toe off position is reached.

19. The hydraulic swing phase control unit of claim 17, wherein said means for providing increased resistance to extension after the predetermined angle is reached, comprises means for providing variable resistance to extension after the predetermined angle is reached.