Patent ID: 7168928

Claim:
An air driven hydraulic pump comprising two opposed pneumatic cylinders; two pneumatic pistons slideable in the opposed pneumatic cylinders, respectively, each pneumatic piston including an outward face and an attachment face; a shaft assembly extending between the two opposed pneumatic pistons and coupled with the attachment face of each piston; a valve assembly in selective fluid communication with both the attachment face and the outward face of each pneumatic piston in the opposed pneumatic cylinders and in communication with a source of pressurized air, the valve assembly being constructed and arranged to direct air pressure to the attachment face of one of the two pneumatic pistons and the outward face of the other of the two pneumatic pistons at the same time and alternately to the outward face of the one of the two pneumatic pistons and the attachment face of the other of the two pneumatic pistons at the same time; hydraulic cylinders extending from the opposed pneumatic cylinders, respectively; hydraulic plungers slideable in the hydraulic cylinders, respectively, the hydraulic plungers being fixed to the two pneumatic pistons, respectively.