Artificial ankle joint with cushion structures and prosthetic devices formed therewith

A prosthetic device adapted to be worn by a human amputee, comprising:

• (a) a proximal portion adapted to be secured to a residual leg extremity of the amputee;
• (b) a distal foot structure that extends along a longitudinal axis;
• (c) a mounting base assembly adapted to be secured to said foot structure, said mounting base assembly including a mounting plate secured to said foot structure;
• (d) a socket mounted to said mounting base assembly, said socket having a cavity formed therein;
• (e) a shank portion including a head disposed in the cavity of said socket and a shaft adapted to mount to said proximal portion, said shank portion pivotable between first and second pivot positions on either side of a neutral position respectively corresponding to a plantarflexion, dorsiflexion and neutral positions of a human foot and ankle;
• (f) a pair of bumper elements interposed between said mounting plate and said socket, there being one of said bumper elements on each lateral side of said foot structure;
• and
• (g) a load-sensitive locking mechanism associated with said socket and said head, said locking mechanism operative in response to a triggering compressive force between said socket and head in excess of a threshold magnitude to cause said head to lock with respect to said socket at a selected locking position between the first and second pivot positions thereby to prevent relative pivotal movement of said head and said socket and operative in an absence of the triggering compressive force to permit relative pivotal movement of said head and said socket between the first and second pivot positions.

In a prosthetic leg device adapted to be worn by a human amputee wherein said leg device has a proximal end portion adapted to be secured to the amputee and a distal foot structure, the improvement comprising an ankle joint disposed between said proximal end portion and said foot structure, said ankle joint including a mounting plate assembly having a mounting plate secured to said foot structure and a socket secured to said mounting plate, said socket having a socket cavity, and including a head assembly including a head nestably received in the socket cavity, a shaft extending outwardly therefrom and secured to said proximal end portion of said leg device, and a shoulder plate disposed on said shaft for relative movement therewith, said socket, said head and said shaft defining a socket and head assembly with said head being relatively pivotable with respect to said socket about a pivot axis between first and second pivot positions corresponding to plantarflexion and dorsiflexion of said foot structure, respectively, and including a spring element associated with said socket and head assembly and operative to bias said head into the second pivot position, said socket and head assembly including a first cushion element independent of said spring element and operative to attenuate relative pivotal movement of said head at the first pivot position, said first cushion element being disposed on said socket and oriented so that said shoulder plate attacks said first cushion element when said head and said socket move into the first pivot position, and including a pair of bumper elements interposed between said mounting plate and said socket, there being one of said bumper elements on each lateral side of said foot structure.