Robust adaptable foot prosthesis

A prosthetic foot device comprising:

• a linkage system comprising:
• an upper portion including a first contact surface;
• a lower portion having a second contact surface that contacts the first contact surface;
• a first pin having a first end and a second end, wherein the first pin is positioned through a first through-hole in the upper portion and further through a second through-hole in the lower portion;
• and
• a second pin having a first end and a second end, wherein the second pin is positioned through a third through-hole in the upper portion and further through a fourth through-hole in the lower portion, wherein the upper portion is rotatably coupled to the lower portion via the first pin and the second pin such that the upper portion rotates from a first position in which a top surface of the upper portion and a bottom surface of the lower portion are parallel to one another to a second position in which a non-zero angle exists between the top surface of the upper portion and the bottom surface of the lower portion, wherein the first through-hole in the upper portion comprises a first curved slot having a first width greater than a first diameter of the first pin such that the first pin moves laterally within the first curved slot as the upper portion rotates with respect to the lower portion from the first position to the second position, wherein the third through-hole in the upper portion comprises a second curved slot having a second width greater than a second diameter of the second pin such that the second pin moves laterally within the second curved slot as the upper portion rotates with respect to the lower portion from the first position to the second position, and wherein the second through-hole and the fourth through-hole in the lower portion each comprise a cylindrical through-hole.