Multi-chamber vacuum pump

A weight activated vacuum pump for a prosthetic device, comprising:

• a hollow elongate structure;
• a piston positioned within the hollow elongate structure;
• a first fluid pumping chamber positioned within the hollow elongate structure and arranged on a first side of the piston, the first fluid pumping chamber having a variable volume as the piston moves axially relative to the shaft;
• a second fluid pumping chamber positioned within the hollow elongate structure and arranged on a second side of the piston opposite the first side, the second fluid pumping chamber having a variable volume as the piston moves axially relative to the shaft;
• wherein the first fluid pumping chamber is fluidly connectable to a socket of the prosthetic device through a first valve and fluidly connected to the second fluid pumping chamber through a second valve, and the second fluid pumping chamber is fluidly connected to atmosphere through a third valve;
• wherein moving the piston in a first axial direction draws air from the socket into the first fluid pumping chamber and expels air from the second fluid pumping chamber, and moving the piston in a second axial direction opposite the first axial direction forces air from the first fluid pumping chamber into the second fluid pumping chamber.

A weight activated prosthetic vacuum pump comprising:

• a plurality of fluid pumping chambers each comprising:
• an enclosed space having a variable volume, the enclosed space being sealed;
• at least one intake port;
• at least one intake one-way valve to permit air to enter the fluid pumping chamber and prevent air from exiting the fluid pumping chamber;
• at least one exhaust port;
• at least one exhaust one-way valve to permit air to exit the fluid pumping chamber;
• wherein the plurality of fluid pumping chambers are connected such that at least one fluid pumping chamber exhausts air from its at least one exhaust port into the at least one intake port of another fluid pumping chamber.