Variable resistance cell

• US 20030120353A1
• Filed: 02/05/2003
• Published: 06/26/2003
• Est. Priority Date: 06/30/2000
• Status: Active Grant

• Current Assignee: Freedom Innovations LLC (Ottobock SE & Co. KGaA)
• Original Assignee: Roland J. Christensen
• Inventors: Christensen, Roland J.
• Granted Patent: US 6,875,241 B2
• Time in Patent Office: Days
• US Class Current: 623/26
• CPC Class Codes: A43B 13/188 Differential cushioning regions
• CPC Class Codes: A43B 13/189 filled with a non-compressible fluid, e.g. gel, water
• CPC Class Codes: A43B 3/0031 provided with a pocket, e.g. for keys or a card
• CPC Class Codes: A43B 3/34 with electrical or electronic arrangements
• CPC Class Codes: A61F 2/66 Feet; Ankle joints
• CPC Class Codes: A61F 2/76 Means for assembling, fitting or testing prostheses, e.g. for measuring or balancing, e.g. alignment means
• CPC Class Codes: A61F 2/7812 Interface cushioning members placed between the limb stump and the socket, e.g. bandages or stockings for the limb stump
• CPC Class Codes: A61F 2/80 Sockets, e.g. of suction type
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30462 retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2002/30469 using band clamps
• CPC Class Codes: A61F 2002/30471 connected by a hinged linkage mechanism, e.g. of the single-bar or multi-bar linkage type
• CPC Class Codes: A61F 2002/5003 having damping means, e.g. shock absorbers for implantable joints A61F2002/30563
• 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 2002/5009 having two or more elastomeric blocks
• 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 2002/6614 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 2002/6671 C-shaped
• CPC Class Codes: A61F 2002/6678 : L-shaped
• CPC Class Codes: A61F 2220/0041 : using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2220/0075 : sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2220/0091 : connected by a hinged linkage mechanism, e.g. of the single-bar or multi-bar linkage type

Abstract

A variable resistance cell and method provides a variable resistance response to a load factor, such as a load, a load rate, a strain, a strain rate, a pressure, or a deflection. A variable viscosity fluid is displacable between first and second chambers of an enclosure though an orifice in response to the load factor. The variable viscosity fluid has a viscosity that is variable corresponding to the load factor to vary an ability of the variable viscosity fluid to flow through the orifice. The variable viscosity fluid can be a shear stiffening material that increases in viscosity with an increase in a load factor applied to the shear stiffening material, a magneto rheologic fluid responsive to a magnetic field, or an electro rheologic fluid responsive to an electric field. The enclosure can be compressible between first and second positions. In the first position, the cell is responsive to a relatively larger load factor and has a first larger dimension in which a lesser amount of the variable viscosity fluid passes through the orifice into the second chamber. In the second position, the cell is responsive to a relatively smaller load factor and has a second smaller dimension in which a greater amount of the variable viscosity fluid passes through the orifice into the second chamber

Claims

1. A variable resistance cell device configured to provide a variable resistance response to a load factor, the device comprising:

a) an enclosure with first and second chambers;

b) an orifice, operatively disposed between the first and second chambers, and sized to provide resistance against fluid flow therethrough;

c) a variable viscosity fluid, disposed in the enclosure and displacable between the first and second chambers though the orifice in response to the load factor; and

d) the variable viscosity fluid having a viscosity that is variable corresponding to the load factor to vary an ability of the variable viscosity fluid to flow through the orifice; and

e) the enclosure being compressible between;

1) a first position in response to a relatively larger load factor having a first larger dimension and in which a lesser amount of the variable viscosity fluid passes through the orifice into the second chamber; and

2) a second position in response to a relatively smaller load factor having a second smaller dimension and in which a greater amount of the variable viscosity fluid passes through the orifice into the second chamber.

2. A device in accordance with claim 1, further comprising:

a) a spring, coupled to the enclosure, and biasing the enclosure to the first position.

3. A device in accordance with claim 1, wherein the enclosure is resilient and biased to the first position.

4. A device in accordance with claim 1, wherein the enclosure is flexible.

5. A device in accordance with claim 4, wherein the enclosure flexes outwardly in the second position to form the second chamber.

6. A device in accordance with claim 1, wherein the enclosure includes a tubular sleeve.

7. A device in accordance with claim 1, further comprising:

a) means for varying the viscosity of the variable viscosity fluid in response to the load factor.

8. A device in accordance with claim 1, wherein the load factor includes at least one load factor selected from the group consisting of:

a load, a load rate, a load acceleration, a strain, a strain rate, a strain acceleration, a pressure, a pressure rate, a pressure acceleration, a deflection, a deflection rate, and a deflection acceleration.

9. A device in accordance with claim 1, wherein the variable viscosity fluid includes a shear stiffening material that increases in viscosity with an increase in the load factor applied to the shear stiffening material.

10. A device in accordance with claim 1, wherein the variable viscosity fluid includes at least one fluid selected from the group consisting of:

a magneto rheologic fluid responsive to a magnetic field, and an electro rheologic fluid responsive to an electric field.

11. A device in accordance with claim 10, further comprising:

a) a transducer to sense a load factor;

b) a power source, coupled to the transducer;

c) control electronics, coupled to the transducer and the variable viscosity fluid, to apply an electric or magnetic field in response to the load factor sensed by the transducer.

12. A device in accordance with claim 11, wherein the control electronics are programmable.

13. A device in accordance with claim 11, wherein the power source includes a generator.

14. A device in accordance with claim 1, further comprising:

a block, disposed in the enclosure, dividing the enclosure into the first and second chambers and forming the orifice between the block and the enclosure.

15. A device in accordance with claim 14, further comprising:

a cup, formed around the first chamber, to receive the block therein in the second position.

16. A device in accordance with claim 15, wherein the block and the cup include a magnetic material.

17. A device in accordance with claim 1, wherein the orifice includes a variable orifice with a variable size.

18. A device in accordance with claim 1, wherein the enclosure is disposed between first and second members of a prosthetic foot.

19. A device in accordance with claim 1, wherein the enclosure is disposed in a shoe between upper and lower surfaces of an outsole.

20. A variable resistance cell device, comprising:

a) a flexible tubular sleeve forming an enclosure;

b) a block, disposed in the tubular sleeve, dividing the enclosure into first and second compartments with an orifice therebetween; and

c) a variable viscosity fluid, disposed in the enclosure of the tubular sleeve, the variable viscosity fluid having a viscosity that is variable corresponding to the load factor to vary an ability of the variable viscosity fluid to flow through the orifice.

21. A device in accordance with claim 20, further comprising:

spring, disposed in the tubular sleeve, to bias the tubular sleeve to an expanded configuration.

22. A device in accordance with claim 20, wherein the flexible tubular sleeve is resilient and biased to an expanded configuration.

23. A device in accordance with claim 20, wherein the tubular sleeve flexes outwardly to form the second chamber.

24. A device in accordance with claim 20, further comprising:

a) means for varying the viscosity of the variable viscosity fluid in response to a load factor.

25. A device in accordance with claim 24, wherein the load factor includes at least one load factor selected from the group consisting of:

a load, a load rate, a load acceleration, a strain, a strain rate, a strain acceleration, a pressure, a pressure rate, a pressure acceleration, a deflection, a deflection rate, and a deflection acceleration.

26. A device in accordance with claim 20, wherein the variable viscosity fluid includes a shear stiffening material that increases in viscosity with an increase in a load factor applied to the shear stiffening material.

27. A device in accordance with claim 20, wherein the variable viscosity fluid includes at least one fluid selected from the group consisting of:

a magneto rheologic fluid responsive to a magnetic field, and an electro rheologic fluid responsive to an electric field.

28. A device in accordance with claim 27, further comprising:

a) a transducer to sense a load factor;

b) a power source, coupled to the transducer;

c) control electronics, coupled to the transducer and the variable viscosity fluid, to apply an electric or magnetic field in response to the load factor sensed by the transducer.

29. A device in accordance with claim 20, further comprising:

a cup, disposed in the tubular sleeve, to receive the block therein as the tubular sleeve is compressed.

30. A device in accordance with claim 29, wherein the block and the cup include a magnetic material.

31. A device in accordance with claim 20, wherein the tubular sleeve is disposed between first and second members of a prosthetic foot.

32. A device in accordance with claim 20, wherein the tubular sleeve is disposed in a shoe between upper and lower surfaces of an outsole.

33. A method for variably resisting a load factor, comprising the steps of:

a) displacing a variable viscosity fluid through a variable resistance cell with an enclosure with two chambers and an orifice positioned between the two chambers so that the variable viscosity fluid can flow between the two chambers through the orifice;

b) compressing the variable resistance load cell by applying a load factor to the variable resistance cell; and

c) varying the viscosity of the fluid in response to the load factor by increasing the viscosity for a relatively larger load factor, and decreasing the viscosity for a relatively smaller load factor.

34. A method in accordance with claim 33, further comprising the step of:

positioning the cell between two members of a prosthetic foot.

35. A method in accordance with claim 33, further comprising the step of:

programming control electronics to vary the viscosity of the fluid in response to the load factor, and a predetermined program.