Magnetorheological fluid compositions and prosthetic knees utilizing same

• US 7,335,233 B2
• Filed: 03/15/2006
• Issued: 02/26/2008
• Est. Priority Date: 05/02/2003
• Status: Active Grant

• Current Assignee: Ossur hf
• Original Assignee: Ossur hf
• Inventors: Hsu, Henry, Prince, Stephen W., Lindsay, Michael W., Lukasiewicz, Ronald J., Palmer, Michael Lars, Bisbee, Charles R. III
• Primary Examiner(s): Gartenberg; Ehud
• Assistant Examiner(s): WOLF, MEGAN YARNALL
• Application Number:
  US11/376,651
• Publication Number:
  US 20060178753A1
• Time in Patent Office: 713 Days
• Field of Search: 623/26
• US Class Current: 623/39
• CPC Class Codes: A61F 2/68 Operating or control means
• CPC Class Codes: A61F 2002/5004 operated by electro- or magnetorheological fluids
• 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 2002/6818 for braking
• CPC Class Codes: C10M 171/001 Electrorheological fluids; smart fluids
• CPC Class Codes: C10M 2201/05 Metals; Alloys
• CPC Class Codes: C10M 2213/06 Perfluoro polymers
• CPC Class Codes: C10M 2213/0606 used as base material
• CPC Class Codes: C10N 2010/14 Group 7
• CPC Class Codes: C10N 2010/16 Groups 8, 9, or 10
• CPC Class Codes: C10N 2020/011 Cloud point
• CPC Class Codes: C10N 2020/02 Viscosity; Viscosity index
• CPC Class Codes: C10N 2020/06 Particles of special shape or size
• CPC Class Codes: C10N 2030/02 Pour-point; Viscosity index
• CPC Class Codes: C10N 2060/00 Chemical after-treatment of the constituents of the lubricating composition
• CPC Class Codes: C10N 2060/06 by epoxydes or oxyalkylation reactions
• CPC Class Codes: C10N 2060/09 Treatment with nitrogen containing compounds
• CPC Class Codes: C10N 2060/12 by phosphorus or a compound containing phosphorus, e.g. PxSy
• CPC Class Codes: H01F 1/447 characterised by magnetoviscosity, e.g. magnetorheological, magnetothixotropic, magnetodilatant liquids electrorheological fluids C10M171/001

Abstract

The present invention relates in one embodiment to magnetorheological fluids utilized in prosthetic joints in general and, in particular, to magnetorheological fluids utilized in controllable braking systems for prosthetic knee joints. Preferred magnetorheological fluids of the present invention comprises polarizable iron particles, a carrier fluid, and optionally an additive. Preferred additives include, but are not limited to functionalized carrier fluids as well as derivatized fluoropolymers. Preferred carrier fluids include, but are not limited, to perfluorinated polyethers.

Claims

1. A prosthetic knee system comprising a magnetorheological fluid and a prosthetic knee, the fluid being provided within the prosthetic knee;

wherein the magnetorheological fluid comprises polarizable particles and a fluid component;

wherein the fluid component comprises a carrier fluid and an additive; and

wherein the additive comprises at least one of a perfluoropropene and oxygen polymerized amide derivative, and a functionalized perfluorinated polyether fluid;

wherein the functionalized perfluorinated polyether fluid comprises a poly(hexafluoropropylene epoxide) with a carboxylic acid located on the terminal fluoromethylene group.

2. The prosthetic knee system of claim 1, wherein the prosthetic knee operates in shear mode.

3. The prosthetic knee system of claim 1, wherein the polarizable particles comprise iron particles.

4. The prosthetic knee system of claim 1, wherein the polarizable particles range in size from about 0.2 to about 50 microns.

5. The prosthetic knee system of claim 1, wherein the polarizable particles comprise about 1 to about 60% (v/v) of the total magnetorheological fluid volume.

6. The prosthetic knee system of claim 1, wherein the carrier fluid is selected from the group consisting of silicone, hydrocarbon, esters, ethers, fluorinated esters, fluorinated ethers, mineral oil, unsaturated hydrocarbons, and combinations thereof.

7. The prosthetic knee system of claim 1, wherein the functionalized perfluorinated polyether fluid additive comprises one or more functional groups selected from the group consisting of silane, phosphate, hydroxyl, carboxylic acid, amine dihydroxyl, ethoxy ether, isocyanate, aromatic, ester and alcohol functions.

8. The prosthetic knee system of claim 1, wherein the additive comprises from about 0.1 to about 20% (v/v) of the fluid component.

9. The prosthetic knee system of claim 1, comprising:

about 32% (v/v) polarizable particles; and

about 68% (v/v) fluid component;

wherein said fluid component comprises about 5% (v/v) poly(hexafluoropropylene epoxide) with a carboxylic acid located on the terminal fluoromethylene group additive and about 95% (v/v) perfluorinated polyether carrier fluid.

10. An anatomical joint system comprising a magnetorheological fluid and an anatomical joint, the fluid being provided within the anatomical joint;

wherein the magnetorheological fluid comprises polarizable particles and a fluid component;

wherein the fluid component comprises a carrier fluid and an additive; and

wherein the additive comprises at least one of a perfluoropropene and oxygen polymerized amide derivative, and a functionalized perfluorinated polyether fluid;

wherein the functionalized perfluorinated polyether fluid comprises a poly(hexafluoropropylene epoxide) with a carboxylic acid located on the terminal fluoromethylene group.

11. The anatomical joint system of claim 10, wherein the anatomical joint is a prosthetic knee.

12. The anatomical joint system of claim 10, wherein the anatomical joint is a prosthetic joint.

13. The anatomical joint system of claim 10, wherein the anatomical joint operates in shear mode.

14. The anatomical joint system of claim 10, wherein the carrier fluid is selected from the group consisting of silicone, hydrocarbon, esters, ethers, fluorinated esters, fluorinated ethers, mineral oil, unsaturated hydrocarbons, and combinations thereof.

15. The anatomical joint system of claim 10, wherein the polarizable particles comprise iron particles.

16. The anatomical joint system of claim 10, wherein the polarizable particles range in size from about 0.2 to about 50 microns.

17. The anatomical joint system of claim 10, wherein the polarizable particles comprise about 1 to about 60% (v/v) of the total magnetorheological fluid volume.

18. The anatomical joint system of claim 10, wherein the functionalized perfluorinated polyether fluid additive comprises one or more functional groups selected from the group consisting of silane, phosphate, hydroxyl, carboxylic acid, amine dihydroxyl, ethoxy ether, isocyanate, aromatic, ester and alcohol functions.

19. The anatomical joint system of claim 10, comprising:

about 32% (v/v) polarizable particles; and

about 68% (v/v) fluid component;

wherein said fluid component comprises about 5% (v/v) poly(hexafluoropropylene epoxide) with a carboxylic acid located on the terminal fluoromethylene group additive and about 95% (v/v) perfluorinated polyether carrier fluid.

20. An anatomical shear mode device comprising a magnetorheological fluid and a damper, the fluid being provided within the damper;

wherein the magnetorheological fluid comprises polarizable particles and a fluid component;

wherein the fluid component comprises a carrier fluid and an additive; and

the additive comprises at least one of a perfluoropropene and oxygen polymerized amide derivative, and a functionalized perfluorinated polyether fluid;

wherein the functionalized perfluorinated polyether fluid comprises a poly(hexafluoropropylene epoxide) with a carboxylic acid located on the terminal fluoromethylene group.

21. The anatomical shear mode device of claim 20, wherein the polarizable particles comprises iron particles.

22. The anatomical shear mode device of claim 20, wherein the damper operates in shear mode.

23. The anatomical shear mode device claim 20, wherein the anatomical shear mode device is a prosthetic device.

24. The anatomical shear mode device claim 23, wherein the prosthetic device is a prosthetic knee.

25. The anatomical shear mode device of claim 20, comprising:

about 32% (v/v) polarizable particles; and

about 68% (v/v) fluid component;

wherein said fluid component comprises about 5% (v/v) poly(hexafluoropropylene epoxide) with a carboxylic acid located on the terminal fluoromethylene group additive and about 95% (v/v) perfluorinated polyether carrier fluid.

26. The anatomical shear mode device of claim 20, wherein the polarizable particles range in size from about 0.2 to about 50 microns.

27. The anatomical shear mode device of claim 20 wherein the polarizable particles comprise about 1 to about 60% (v/v) of the total magnetorheological fluid volume.

28. The anatomical shear mode device of claim 20 wherein the additive comprises from about 0.1 to about 20% (v/v) of the fluid component.

29. The anatomical shear mode device of claim 20 wherein the functionalized perfluorinated polyether fluid additive comprises one or more functional groups selected from the group consisting of silane, phosphate, hydroxyl, carboxylic acid, amine dihydroxyl, ethoxy ether, isocyanate, aromatic, ester and alcohol functions.