Carbon fiber prosthetic foot with hollow cross sections

Abstract

A hollow tubulous composite structure and method for prosthetic limbs is described.

What is claimed is: 
     
         1 . A prosthetic foot comprising:
 a mounting element securable to a lower limb prosthesis with structure for securing to a residual limb;   a tubulous fiber composite member attached to the mounting element, the tubulous fiber composite member in the form an elongated hollow shape configured to store and release energy, and that follows a not-straight path corresponding to a longitudinal centerline of the shape   
       the path sweeping an angular change between any two points located on the path, 
       the angular change measured by projecting the path onto and plane fixed in space with respect to the foot, 
       the composite member having fibers plies oriented at 0 degrees and +45 degrees and −45 degrees with respect to the path. 
     
     
         2 . The prosthetic foot of  claim 1  where the path sweeps a cumulative angular change of at least 160 degrees between two points located on the path, 
     
     
         3 . The prosthetic foot of  claim 1  where the path sweeps a cumulative angular change of at least 10 degrees and less then 100 degrees between two points located on the path, 
     
     
         4 . The prosthetic foot of  claim 1  wherein the primary axis is a vertical axis, or a lateral axis, or a longitudinal axis. 
     
     
         5 . The prosthetic foot of  claim 1  wherein in the tubulous fiber composite member comprises more than one elongated hollow shape. 
     
     
         6 . The prosthetic foot of  claim 1  wherein the elongated hollow shape follows a path where at least a portion thereof divides from a single path into two or more diverging paths. 
     
     
         7 . The prosthetic foot of  claim 1  wherein the elongated hollow shape follows a single undivided path. 
     
     
         8 . The prosthetic foot of  claim 1  wherein the longitudinal centerline of the shape is branched, or unbranched. 
     
     
         9 . The prosthetic foot of  claim 1  wherein the elongated hollow shape has a variable cross-section along the longitudinal centerline. 
     
     
         10 . The prosthetic foot of  claim 1  wherein the longitudinal center line is in the form of a helix with an axis substantially parallel to the vertical or lateral axis. 
     
     
         11 . The prosthetic foot of  claim 1  wherein the elongated hollow shape has more than one hollow cavity. 
     
     
         12 . A method for manufacture of a tubulous composite prosthetic foot member, the method comprising:
 compressing an uncured composite against interior cavity surfaces of a closed female mold to form an uncured elongated hollow shape with an exterior surface, with at least 90% of the external surface being formed directly against the cavity surfaces, the cavity surfaces being on hard metal tooling of essentially fixed geometry,   
       the mold interior surface configured to form the uncured shape as an elongated hollow shape that follows a not-straight path corresponding to a longitudinal centerline of the shape, 
       the not-straight path sweeping an angular change between any two points located on the path, the angular change measured by projecting the path onto any plane fixed in space with respect to the foot;
 curing the uncured shape by heating the female mold to form a cured shape; 
 removing the cured shape from the mold and removing portions of the cured shape that were not formed directly against the cavity surfaces to form the tubulous composite prosthetic foot member.