Pump mechanism for vacuum suspension system

1. A vacuum suspension system comprising:

a pump mechanism including:

a first member;

a second member;

a bladder disposed between the first and second members and defining a first fluid chamber located between the first and second members;

a second fluid chamber located between the first and second members, the second fluid chamber fluidly separate from the first fluid chamber, wherein an increase in volume of the first fluid chamber mechanically expands the second fluid chamber to create a vacuum pressure in the second fluid chamber; and

a pressure source fluidly connected to the bladder and separate from the pump mechanism, the pressure source arranged to selectively compress and force fluid into the first fluid chamber to increase the volume of the first fluid chamber.

2. The system of claim 1 , wherein the volume increase in the first fluid chamber mechanically separates the first and second members of the pump mechanism to create the vacuum pressure in the second fluid chamber.

3. The system of claim 1 , further comprising a membrane having an outer edge portion secured to the first member of the pump mechanism, the second fluid chamber having a volume defined between the first member of the pump mechanism and the membrane.

4. The system of claim 3 , wherein the membrane deforms to vary the volume of the second fluid chamber.

5. The system of claim 3 , wherein the increase of volume in the first fluid chamber pulls the first member of the pump mechanism and a portion of the membrane apart to increase the volume of the second fluid chamber.

6. The system of claim 3 , wherein the first member of the pump mechanism comprises a housing defining first and second ports, the second fluid chamber being in fluid communication with the first and second ports.

7. The system of claim 6 , further comprising a connector attached to a portion of the membrane opposite the first member of the pump mechanism.

8. The system of claim 7 , wherein the second member of the pump mechanism comprises a base member situated under the housing and connected to the connector.

9. The system of claim 8 , further comprising a bladder situated between the housing and the base member, the bladder having a torus configuration defining a center opening, the connector extending through the center opening of the bladder.

10. The system of claim 1 , further comprising a resilient member engaging at least one of the first and second members of the pump mechanism, and arranged to bias the second fluid chamber toward a zero or near zero volume.

11. The system of claim 10 , wherein the resilient member is arranged to bias the first fluid chamber toward a zero or near zero volume.

12. A prosthetic system comprising:

a pump mechanism operatively connectable to a prosthetic foot, the pump mechanism including:

a housing defining first and second ports;

a membrane having an outer edge portion secured to the housing;

a base member disposed below the membrane;

a bladder disposed between the housing and the base member;

a first fluid chamber with a volume defined by the bladder;

a second fluid chamber with a volume defined between the housing and a first side of the membrane, the second fluid chamber fluidly separate from the first fluid chamber and in fluid communication with the first and second ports,

wherein an increase in volume of the first fluid chamber mechanically expands the second fluid chamber to create a vacuum pressure in the second fluid chamber.

13. The system of claim 12 , further comprising a connector attached to a second side of the membrane opposite the first side of the membrane, the connector connecting the membrane to the base member.

14. A vacuum suspension system comprising:

a pump mechanism including:

a first member;

a second member;

a bladder disposed between the first and second members and defining a first fluid chamber located between the first and second members;

a second fluid chamber located between the first and second members, the second fluid chamber fluidly separate from the first fluid chamber, wherein an increase in volume of the first fluid chamber mechanically expands the second fluid chamber to create a vacuum pressure in the second fluid chamber; and

a pressure source fluidly connected to the bladder and separate from the pump mechanism, the pressure source arranged to selectively compress and force fluid into the first fluid chamber to increase the volume of the first fluid chamber, wherein the volume increase in the first fluid chamber mechanically separates the first and second members of the pump mechanism to create the vacuum pressure in the second fluid chamber.

15. A vacuum suspension system comprising:

a pump mechanism including:

a housing defining first and second ports;

a base member situated under the housing;

a membrane having an outer edge portion secured to the housing;

a connector attached to a portion of the membrane opposite the housing;

a bladder situated between the housing and the base member, the bladder having a torus configuration defining a center opening, the connector extending through the center opening of the bladder;

a first fluid chamber located between the housing and the base member;

a second fluid chamber having a volume defined between the housing and the membrane, the second fluid chamber fluidly separate from the first fluid chamber and in fluid communication with the first and second ports,

wherein an increase in volume of the first fluid chamber mechanically expands the second fluid chamber to create a vacuum pressure in the second fluid chamber.