Further improvements to ankle-foot prosthesis and orthosis capable of automatic adaptation to sloped walking surfaces

A passive, self-adapting ankle-foot prosthetic system comprising a shank structure, a foot structure, an intermediate element interposed between the shank structure and the foot structure, and a clutch;

• the foot structure comprising a foot plate, a shaft for rotatably connecting the foot structure to the intermediate element, and a housing including a base configured to receive the shaft;
• the intermediate structure comprising a first arbor;
• the shank structure comprising second arbor and a shock-absorbing pylon for engaging the clutch upon loading the prosthetic system to resist externally-applied dorsiflexion moments and disengaging the clutch upon unloading the prosthetic system to return the foot structure to a neutral orientation relative to the shank structure;
• the clutch comprising a spring being operatively interposed between the first arbor and second arbor on the shaft and a collar for selectively engaging the spring;
• an engagement linkage operatively connecting the pylon to the collar;
• a first bumper received in the housing base and interposed between the intermediate element and the foot structure such that the first bumper is compressed during dorsiflexion;
• and
• one or more second bumpers interposed between the shank structure and the intermediate element for returning an unloaded foot structure to the neutral orientation;
• the first bumper and the one or more second bumpers being in series.