Artificial leg having a lockable knee joint
First Claim
1. An artificial leg comprising an upper limb portion, a lower limb portion, connecting means pivotally connecting the upper limb portion to the lower limb portion, a foot mounted on the lower end of the lower limb portion, and locking means responsive to downward pressure of the upper limb portion with the foot resting on a support surface for locking the upper limb portion in position with respect to the lower limb portion, said connecting means comprising a hinge pin extending transversely of said upper and lower limb portions in front of the center line of gravity in the artificial leg and thereat establishing an axis for monocentric pivotal movements of the limb portions.
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Accused Products
Abstract
The knee pivot or hinge shaft of the artificial limb connecting the upper limb portion and the lower portion is located forward of the center line of gravity in the prosthesis whereby the arc of the foot of the limb is shortened as the foot moves rearwardly from a straightened position of the limb. The knee joint is provided with a locking mechanism which is actuated to lock the upper limb portion to the lower limb portion either by downward pressure applied to the upper limb portion as the artificial limb rests on a support surface or by pressure applied to the heel portion of the foot as it engages a support surface. The actuating lever of the locking mechanism pivots about a first fulcrum to actuate the locking mechanism as pressure is initially applied to the heel of the foot during the amputees stride and, as the weight of the amputee is transferred from the heel to the ball or toe portion of the foot, the actuating lever pivots about a second fulcrum. The locking mechanism remains in the actuated or locked condition as the lock actuating lever moves from one fulcrum to the other.
86 Citations
25 Claims
- 1. An artificial leg comprising an upper limb portion, a lower limb portion, connecting means pivotally connecting the upper limb portion to the lower limb portion, a foot mounted on the lower end of the lower limb portion, and locking means responsive to downward pressure of the upper limb portion with the foot resting on a support surface for locking the upper limb portion in position with respect to the lower limb portion, said connecting means comprising a hinge pin extending transversely of said upper and lower limb portions in front of the center line of gravity in the artificial leg and thereat establishing an axis for monocentric pivotal movements of the limb portions.
- 17. An artificial leg comprising an upper limb portion, a lower limb portion, connecting means pivotally connecting the upper limb portion to the lower limb portion, a foot mounted on the lower end of the lower limb portion, first means including a pivotable actuating lever for locking said upper limb portion to said lower limb portion in response to a first predetermined force applied downwardly on said upper limb portion as it rests on a support surface, second means including said pivotable actuating lever for actuating the locking means in response to a second predetermined force applied upwardly on force transmitting means contiguous with the heel portion of said foot as it engages a support surface, first fulcrum means in engagement with said actuating lever about which said lever pivots for actuating said locking means when said first predetermined force is applied downwardly on said upper limb portion, and second fulcrum means in engagement with said actuating lever about which said lever pivots for actuating said locking means when said second predetermined force is applied upwardly on said force transmitting means contiguous with the heel portion of said foot.
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23. An artificial leg comprising an upper limb portion, a lower limb portion, connecting means pivotally connecting the upper limb portion to the lower limb portion and permitting limited vertical movement of said limb portions relative to one another, a foot mounted on the lower end of said lower limb portion, resilient means normally maintaining said upper limb portion biased upwardly away from said lower limb portion, locking means for locking said upper limb portion to said lower limb portion, actuating means including pivotal lever means responsive to said limited vertical movement for actuating said locking means, and force transmitting means operably connecting the heel portion of said foot with said pivotal lever means, said pivotal lever means being responsive to upward pressure on the heel portion of said foot and transmitted thereto by said force transmitting means for actuating said locking means.
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24. An artificial leg comprising an upper limb portion, a lower limb portion, connecting means pivotally connecting said upper limb portion to said lower limb portion, a foot portion attached to the lower end of said lower limb portion, locking means for locking said upper limb portion so said lower limb portion comprising an elongated casing pivotally connected to said lower limb portion and having a downwardly converging, frusto-conical locking surface, a sleeve slidable in said casing, a one-way sprag-type lock device positioned on the upper end of said sleeve opposite said locking surface and movable with said sleeve, lockable rod means having one end thereof slidably mounted in said sleeve and operably engageable with said lock device, the other end of said rod means being pivotally connected to said upper leg portion, resilient means normally biasing said sleeve and the locking device resting thereon to a non-actuated position of said lock device, and means responsive to a predetermined downward force on said artificial leg as it rests on a supporting surface for sliding said sleeve in a direction for actuating said lock device and thereby locking said rod and upper limb portion to said locking surface and said lower limb portion.
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25. An artificial leg comprising an upper limb portion, a lower limb portion, connecting means pivotally connecting the upper limb portion to the lower limb portion, a foot mounted on the lower end of the lower limb portion, locking means responsive to downward pressure on the upper limb portion with the foot resting on a support surface for locking the upper limb portion in position with respect to the lower limb portion, said connecting means comprising pivoting means positioned forward on the center line of gravity in the artificial leg and thereat establishing an axis for monocentric pivotal movements of the limb portions.
Specification