Prosthetic knee

Abstract

A prosthetic knee includes a housing and a brake member pivotally connected to the housing at a first location point. The brake member defines a first pair of slots along a posterior surface of the brake member. A knee shaft extends through the brake member and is secured within a cavity defined by the housing. The knee shaft defines a second plurality of slots along a posterior surface of the knee shaft corresponding in location to the first slots. An extension assist system includes an extension assist link with a body portion and a plurality of arm portions situated in the first slots defined in the brake member and in the second slots defined in the knee shaft. The arm portions are pivotally connected to the knee shaft at a second location point located within the second slots and a distance from the first location point.

1 . A prosthetic knee comprising:
 a housing;   a brake member pivotally connected to the housing at a first location point, the brake member defining a first plurality of slots along a posterior surface of the brake member;   a knee shaft extending through the brake member and secured within a cavity defined by the housing, the knee shaft defining a second plurality of slots along a posterior surface of the knee shaft corresponding in location to the first slots in the brake member;   an extension assist system including an extension assist link having a body portion and a plurality of arm portions situated in the first slots defined in the brake member and in the second slots defined in the knee shaft, the arm portions pivotally connected to the knee shaft at a second location point located within the second slots and a distance from the first location point.   
     
     
         2 . The prosthetic device of  claim 1 , further comprising a piston secured between and engaging a biasing mechanism of the extension assist system and the extension assist link. 
     
     
         3 . The prosthetic device of  claim 2 , wherein a lower surface of the extension assist link defines a convex portion that is complementary shaped to a concave recess defined by the upper surface of the piston for engagement therewith. 
     
     
         4 . The prosthetic knee of  claim 2 , further comprising:
 an extension assist housing receiving the piston and the biasing mechanism, wherein the position of the extension assist housing is adjustable to adjust a biasing force exerted on the knee by the biasing mechanism.   
     
     
         5 . The prosthetic knee of  claim 1 , further comprising a chassis pivotally connected to the brake member. 
     
     
         6 . The prosthetic knee of  claim 5 , further comprising:
 a pylon attached to the chassis; and   an opening defined in a rear of the chassis, the opening arranged to provide access for adjusting compression of the biasing mechanism without removal of a pylon from the prosthetic knee.   
     
     
         7 . The prosthetic knee of  claim 6 , further comprising a brake sleeve interposed between the brake member and the knee shaft. 
     
     
         8 . The prosthetic knee of  claim 7 , wherein when the knee is loaded by the user a contact point is loaded between the housing and the chassis to compress the brake member and the brake sleeve about the knee shaft to create friction between the brake sleeve and the knee shaft to substantially prevent rotation of the housing about the first location point. 
     
     
         9 . The prosthetic knee of  claim 1 , further comprising a lock piece pivotally connected to the housing and movable between a locked position in which the lock piece is engaged with a stop surface protruding from the brake member, and an unlocked position in which the lock piece is disengaged from the stop surface. 
     
     
         10 . The prosthetic knee of  claim 9 , further comprising a torsion spring biasing the lock piece toward the locked position. 
     
     
         11 . The prosthetic knee of  claim 9 , further comprising a set screw extending at least in part through the housing, the set screw arranged to selectively prevent the lock piece from moving into the locking position. 
     
     
         12 . The prosthetic knee of  claim 11 , wherein the set screw selectively engages the lock piece by a recess defined in an outer surface of the lock piece. 
     
     
         13 . The prosthetic knee of  claim 9 , further comprising a cable threaded through the lock piece and arranged for manually moving the lock piece to the unlocked position. 
     
     
         14 . The prosthetic knee of  claim 1 , wherein an inner surface of the housing defines at least one keyway comprising a slot or groove having a rectangular cross-section arranged to receive at least one corresponding key defined on the knee shaft. 
     
     
         15 . The prosthetic knee of  claim 1 , further comprising a brake-play adjustment fastener engaging the brake member, the brake-play adjustment fastener arranged to selectively rotate the brake member about a second location point. 
     
     
         16 . A prosthetic knee comprising:
 a housing;   a chassis;   a brake member pivotally connected to the housing at a first location point and to the chassis at a second location point, the brake member defining a first pair of slots along a posterior surface of the brake member;   a knee shaft extending through the brake member and secured within a cavity defined by the housing, the knee shaft defining a second pair of slots along a posterior surface of the knee shaft corresponding in location to the first slots;   an extension assist system including an extension assist link having a body portion operatively connected to the biasing mechanism and a pair of arm portions situated in the first slots defined in the brake member and in the second slots defined in the knee shaft, the arm portions pivotally connected to the knee shaft at a third location point located within the second slots and a distance from the first location point.   
     
     
         17 . The prosthetic knee of  claim 16 , wherein the extension assist system comprises an extension assist spring arranged to compress and push the knee back toward extension when the knee is in flexion. 
     
     
         18 . The prosthetic knee of  claim 17 , further comprising a brake sleeve interposed between the brake member and the knee shaft. 
     
     
         19 . The prosthetic knee of  claim 17 , further comprising:
 a pylon attached to the chassis; and   an opening defined in a rear of the chassis, the opening arranged to provide access for adjusting compression of the biasing mechanism without removal of a pylon from the prosthetic knee.   
     
     
         20 . A prosthetic system comprising:
 a prosthetic socket arranged to receive a residual limb;   an adaptor connected to the prosthetic socket; and   a prosthetic knee connected to the adaptor, the prosthetic knee including:
 a housing; 
 a brake member pivotally connected to the housing at a first location point, the brake member defining a first plurality of slots along a posterior surface of the brake member; 
 a knee shaft extending through the brake member and secured within a cavity defined by the housing, the knee shaft defining a second plurality of slots along a posterior surface of the knee shaft corresponding in location to the first slots; 
 an extension assist system including a biasing mechanism and an extension assist link having a body portion operatively connected to the biasing mechanism and a plurality of arm portions situated in the first slots defined in the brake member and in the second slots defined in the knee shaft, the arm portions pivotally connected to the knee shaft at a second location point located within the second slots and a distance from the first location point.