Magnetorheologically actuated prosthetic knee
The invention in some embodiments relates to a magnetorheologically actuated prosthetic knee. The knee in one embodiment comprises an extension assist to facilitate knee extension. The knee in another embodiment comprises a dual-stage bumper system that limits the maximum knee rotation. The knee in yet another embodiment comprises a cover that includes a flexible skin and an exoskeleton.
1 - 75 . (canceled)
76 . A prosthetic knee, comprising:
a rotatable first portion, a rotatable second portion, an extension assist and a magnetorheological fluid to substantially control the rotation of said first and second portions, said first and second portions being operably connected to move relative to each other;
wherein rotation of said first portion generally corresponds to rotation of a lower part of a limb and rotation of said second portion generally corresponds to rotation of an upper part of said limb; and
wherein said extension assist comprises a torsion spring with an inner leg operatively coupled to said first portion and an outer leg operatively coupled to said second portion to store energy during rotation in a flexion direction and release energy during rotation in an extension direction to facilitate knee extension.
77 . The prosthetic knee of claim 76 , wherein rotation of said first and second portions is substantially controlled by shearing of said fluid.
78 . The prosthetic knee of claim 77 , wherein said prosthetic knee comprises a plurality of blades that shear said fluid.
79 . The prosthetic knee of claim 76 , wherein said prosthetic knee further comprises a multi-stage bumper system to control maximum rotation of said prosthetic knee, said bumper system including a first bumper assembly and a second bumper assembly with said bumper assemblies being substantially aligned with one another and spaced from one another by a predetermined distance.
80 . The prosthetic knee of claim 79 , wherein at least one of said bumper assemblies comprises a soft bumper and an adjacent hard bumper with said soft bumper extending beyond said hard bumper such that said soft bumper contacts said second portion before said rigid bumper contacts said second portion at maximum extension.
81 . The prosthetic knee of claim 80 , wherein said bumpers are arranged to permit a predetermined hyperextension of said prosthetic knee.
82 . The prosthetic knee of claim 76 , wherein said prosthetic knee further comprises an outer cover that includes a flexible skin and a substantially rigid exoskeleton.
83 . The prosthetic knee of claim 76 , wherein said first portion comprises a substantially central core having an end with a chamfer.
84 . The prosthetic knee of claim 83 , wherein said prosthetic knee further comprises a side plate with a cavity that is fitted over said end of said core so that said chamfer extends beyond said side plate.
85 . The prosthetic knee of claim 84 , wherein at least one of said core and said side plate are fabricated by first annealing in air and then machining.
86 . The prosthetic knee of claim 76 , wherein said prosthetic knee further comprises an electromagnet with a bobbin-less coil.
87 . The prosthetic knee of claim 76 , wherein said fluid resides in a chamber of said prosthetic knee and said chamber has a plurality of cross channels to increase the volume of said chamber.
88 . The prosthetic knee of claim 87 , wherein said channels are spaced from one another and arranged asymmetrically.
89 . The prosthetic knee of claim 76 , wherein said first portion comprises a core and a mandrel connected to said core.
90 . The prosthetic knee of claim 89 , wherein said core is positioned substantially within said second portion and said mandrel extends beyond said second portion.
91 . The prosthetic knee of claim 90 , wherein said core and said mandrel comprise an integral unit.
92 . The prosthetic knee of claim 90 , wherein said spring is fitted over said mandrel.
93 . The prosthetic knee of claim 92 , wherein said mandrel has a slot and said inner leg of said spring extends into said slot.
94 . The prosthetic knee of claim 93 , wherein said extension assist further comprises a bearing that is fitted within a cavity of said mandrel.
95 . The prosthetic knee of claim 76 , wherein said second portion comprises a housing.
96 . The prosthetic knee of claim 95 , wherein said extension assist further comprises a rotatable arm that is connected to said housing and operatively coupled to said outer leg of said spring.
97 . The prosthetic knee of claim 96 , wherein said extension assist further comprises an axle operatively coupled to said arm.
98 . The prosthetic knee of claim 97 , wherein said extension assist further comprises a bearing fitted within a mandrel of said first portion.
99 . The prosthetic knee of claim 98 , wherein said axle extends into said mandrel and has a shank fitted within a cavity of said bearing.
100 . The prosthetic knee of claim 76 , wherein said prosthetic knee comprises a knee actuator that includes said first portion and said second portion.
101 . The prosthetic knee of claim 100 , wherein said prosthetic knee further comprises a control system to control said actuator and said control system comprises a load cell pylon that includes a frame.
102 . The prosthetic knee of claim 101 , wherein said control system comprises a load cell with front and rear force sensors arranged so that there is substantially no cross-talk between said front and rear force sensors.
103 . The prosthetic knee of claim 102 , wherein said control system further comprises a rechargeable power system and an on-board charger for said power system.