Patent ID: 8449265

Claim:
A pump comprising: a housing having a hydraulic chamber; a first piston in the hydraulic chamber; a second piston separating the hydraulic chamber into at least a first subchamber and a second subchamber, and disposed for reciprocal motion within the housing; the first piston defining a third subchamber in the hydraulic chamber, wherein the first piston is movable relative to the second piston; a hydraulic system fluidicly coupled with the first subchamber, the second subchamber, and the third subchamber, the hydraulic system actuatable to: deliver hydraulic fluid to the second subchamber, whereby the second subchamber is pressurized and the second piston translates in a first direction from a stroked back position toward a stroked out position; deliver hydraulic fluid to the first subchamber, whereby the first subchamber is pressurized and the second piston translates in a second direction opposite the first direction from the stroked out position toward the stroked back position; and deliver hydraulic fluid to the third subchamber to move the first piston relative to the second piston; wherein the first piston, the second piston, the first subchamber, the second subchamber, and the third subchamber are aligned along a same central axis.