Abstract: The invention involves improvements to an axial piston fluid device of the type having a housing with a central cavity and a valve plate end, a shaft journaled adjacent its inner end in a bushing mounted in a bore in the valve plate end, and a cylinder barrel surrounding the shaft and rotatable therewith in the cavity and against the valve plate end. The invention utilizes a bushing which has a slot intermediate its ends and the valve plate bore has axial extending recesses leading to and away from the bushing slot. The cylinder barrel and valve end have a series of fluid passageways leading from the cavity to the bore and from the recesses to the space between the cylinder barrel and shaft and then back to the cavity.

Abstract: A constant speed hydraulic drive comprising a variable displacement hydraulic pump controlled to maintain a constant flow of hydraulic fluid even though a prime mover therefor is subject to speed variations. The constant flow rate delivered by the hydraulic pump is at a rate sufficient to drive a load hydraulic motor at a predetermined speed when the load hydraulic motor is subject to any given load. A pilot operated relief valve proportionally bleeds hydraulic fluid from ahead of the hydraulic motor in accordance with the speed and load of the hydraulic motor.

Abstract: A high pressure check valve for an intensifier cylinder and secured in the end of the cylinder so as to reduce the stress on the check valve due to cyclic loading.