Patent ID: 7263829

Claim:
A hydraulic pump apparatus comprising: a housing forming an internal volume and comprising an opening at one end for accessing the internal volume; an end cap comprising: a first face secured to the one end of the housing, wherein the internal volume and the first face define a fluid sump; a second face formed opposite the first face; and a first, second, third and fourth sides, each side extending between the first and second faces, wherein the second and third sides of the end cap are perpendicular to the first and fourth sides of the end cap; a rotatable cylinder block disposed on the first face of the end cap and within the fluid sump; an input shaft extending into the fluid sump and engaging the cylinder block; hydraulic porting formed in the end cap and in fluid communication with the cylinder block, the hydraulic porting comprising: a pair of system ports extending into the first side of the end cap; a first check valve port extending into the second side of the end cap and a second check valve port extending into the third side of the end cap, each check valve port intersecting a different one of the pair of system ports, and wherein the first and second check valve ports are closer to the first side of the end cap than to the fourth side of the end cap; a cross port intersecting the pair of system ports; and a bypass valve port extending into the fourth side of the end cap; a pair of check valves, each check valve disposed in one of the check valve ports; and a bypass valve disposed in the bypass valve port and comprising a first end located inside the end cap and in proximity to one of the pair of system ports, a second end and a peripheral portion between the first and second ends and in proximity to the cross port, the bypass valve having a closed position where it prevents fluid from being communicated between the one of the pair of system ports and the cross port, and an open position where it permits fluid flow between the one of the pair of system ports and the cross port.