Pump system

1. A prosthetic system comprising:

a prosthetic foot including an upper foot element having a concave-forward facing portion and a foot portion extending forwardly therefrom, an intermediate foot element disposed below the upper foot element and having a front portion coupled to the foot portion of the upper foot element, and a lower foot element disposed below the intermediate foot element, wherein the upper foot element and the intermediate foot element are movable relative to one another upon movement of the prosthetic foot; and

a pump system coupled to the prosthetic foot and comprising:

a pump mechanism including a housing defining a cavity and a membrane situated in the cavity, the pump mechanism being movable between an original configuration in which the volume of a fluid chamber defined between the membrane and a bottom of the cavity is zero or near-zero, and an expanded configuration in which the volume of the fluid chamber is increased; and

an arm member extending from the pump mechanism and operatively coupled to the intermediate foot element, the arm member arranged to move the pump mechanism toward at least the expanded configuration upon movement of the intermediate foot element relative to the upper foot element;

wherein a distance between a portion of the pump system and the upper foot element is adjustable to vary sensitivity of the pump mechanism;

wherein the arm member comprises an elongate member defined by the housing and extending downwardly through an opening defined in the upper foot element and toward the intermediate foot element.

2. The prosthetic system of claim 1 , wherein the arm member is selectively engageable with an upper surface of the intermediate foot element and has a rigid configuration.

3. The prosthetic system of claim 1 , wherein a distance between the pump mechanism and the intermediate foot element is adjustable to vary sensitivity of the pump mechanism.

4. The prosthetic system of claim 1 , wherein the elongate member defines a width increasing in a direction toward the intermediate foot element.

5. The prosthetic system of claim 1 wherein the elongate member defines a key arranged to fit in a corresponding keyway defined by the housing.

6. The prosthetic system of claim 1 , wherein the housing includes a main portion, a front portion, and a width that tapers from the main portion toward the front portion of the housing.

7. The prosthetic system of claim 6 , wherein flexion of the housing at the front portion allows the pump mechanism to move between the original configuration and the expanded configuration.

8. The prosthetic system of claim 1 , further comprising:

an ankle portion rotatably attached to the upper foot element; and

a connection unit connected to a rear portion of the ankle portion and a rear end portion of the intermediate foot element, the connection unit being arranged to move the upper and intermediate foot elements relative to one another.

9. The prosthetic system of claim 8 , wherein rotation of the ankle portion in a first direction causes the connection unit to pull the rear end portion of the intermediate foot element toward the upper foot element.

10. The prosthetic system of claim 9 , wherein rotation of the ankle portion in a second direction causes the connection unit to force the rear end portion of the intermediate foot element away from the upper foot element.