Dynamic seals for a prosthetic knee
First Claim
Patent Images
1. A prosthetic knee, comprising:
- a housing comprising a chamber containing a magnetorheological fluid, said fluid comprising a mixture of solid particles and a liquid;
at least one side plate within said housing and forming a barrier to contain said fluid in said chamber; and
at least one dynamic seal fitted between said housing and said side plate to contain said fluid in said chamber during relative rotation between said housing and said side plate, said dynamic seal having a tensioned spring with coils being spaced by a distance at least as large as the largest size of said particles of said fluid;
wherein said side plate has a hardened outer rim that engages said dynamic seal, and wherein said outer rim has a coating of titanium nitride.
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Accused Products
Abstract
The invention in some embodiments relates to a dynamic seal for a prosthetic knee. The dynamic seal in one embodiment is utilized to seal a magnetorheological fluid comprising a liquid and solid particles within a chamber of the knee. The dynamic seal embodiments are specially configured with a pre-loaded tensioned garter spring which has a coil spacing that is at least as large as the size of the particles or maximum size of the particles in the magnetorheological fluid. Desirably, this allows the magnetorheological fluid particles to flow in and out of the dynamic seal without clogging the seal and advantageously provides for a reliable dynamic seal.
255 Citations
17 Claims
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1. A prosthetic knee, comprising:
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a housing comprising a chamber containing a magnetorheological fluid, said fluid comprising a mixture of solid particles and a liquid; at least one side plate within said housing and forming a barrier to contain said fluid in said chamber; and at least one dynamic seal fitted between said housing and said side plate to contain said fluid in said chamber during relative rotation between said housing and said side plate, said dynamic seal having a tensioned spring with coils being spaced by a distance at least as large as the largest size of said particles of said fluid; wherein said side plate has a hardened outer rim that engages said dynamic seal, and wherein said outer rim has a coating of titanium nitride. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A prosthetic knee, comprising:
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a housing comprising a chamber containing a magnetorheological fluid, said fluid comprising a mixture of solid particles and a liquid, the particles having a maximum size in the range from about 2 μ
m to about 4 μ
m;at least two side plates forming a barrier to contain fluid in said chamber; and at least two dynamic seals, each fitted between said housing and one of said side plates to contain said fluid in said chamber during relative rotation between said housing and said side plates, said dynamic seals comprising a tensioned spring with coils being spaced by a distance at least as large as the largest size of said particles of said fluid, in the range from about 2.5 μ
m to about 40 μ
m. - View Dependent Claims (14, 15)
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16. A prosthetic knee, comprising:
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a housing comprising a chamber containing a magnetorheological fluid, said fluid comprising a mixture of solid particles and a liquid; at least one side plate within said housing and forming a barrier to contain said fluid in said chamber; and at least one dynamic seal fitted between said housing and said side plate to contain said fluid in said chamber during relative rotation between said housing and said side plate, said dynamic seal having a tensioned spring with coils being spaced by a distance at least as large as the largest size of said particles of said fluid; wherein said particles have a maximum size in the range from about 2 μ
m to about 4 μ
m, and wherein adjacent coils are spaced by a distance in the range from about 2.5 μ
m to about 40 μ
m.
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17. A prosthetic knee, comprising:
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a housing comprising a chamber containing a magnetorheological fluid, said fluid comprising a mixture of solid particles and a liquid; at least one side plate within said housing and forming a barrier to contain said fluid in said chamber; and at least one dynamic seal fitted between said housing and said side plate to contain said fluid in said chamber during relative rotation between said housing and said side plate, said dynamic seal having a tensioned spring with coils being spaced by a distance at least as large as the largest size of said particles of said fluid; wherein said dynamic seal has a sealing lip that is loaded by said spring to apply pressure on said side plate and said sealing lip has a tip that dynamically engages an outer rim of said side plate, and wherein said sealing lip forms a fluid side angle with said outer rim and said angle is in the range from about 60°
to about 75°
.
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Specification