Abstract: An axially oriented variable displacemnt pistoned device adaptable for use as motor and having a pivoted swash plate angularly positionable for establishing displacement of the device is fitted with externally mounted low pressure hydraulic actuators operably connected with the swash plate for operation thereof. Adjustable stops are provided in the device body to limit travel of the swash plate under urging of the low pressure hydraulic actuators.

Abstract: A combined summing and underspeed valve including a valve body having a bore, a spool within the bore, an outlet from the bore in the body intermediate the ends of the bore, a pair of spaced inlets in the bore for receiving fluid under pressure to apply force to opposite ends of the spool, at least two additional inlets in the body for receiving fluid under pressure to apply force to one of the ends of the spool, and pistons for isolating fluid from the inlet of the pair applying force to the spool one end from fluid from the additional inlets while applying force to the spool.

Abstract: A pump control assembly for a variable displacement pump has adjustable biasing means for providing improved control of the pump.

Abstract: A pump assembly having at least two variable displacement pumps each having a separate pump control assembly are interconnected for control in response one to the other. Each pump control assembly has first and second biasing means acting on a respective swash plate. The first and second biasing means have interconnecting fluid pathways formed through a pump control housing. Means are provided within the housings for modifying the discharge pressures of the separate pumps to provide a resultant pressure signal for controlling the second biasing means.

Abstract: In order to reduce noise and erosion within a hydrostatic translating unit having a reversible mode of operation, preferably a pump, of the type having a cylinder barrel defining a plurality of piston bores with the cylinder barrel being rotatable relative to a cylinder head for periodically communicating the piston bores with first and second pressure ports or passages, a restrictive orifice and shuttle valve are arranged in parallel communication between each pressure port and an intermediate port positioned for communication with each cylinder bore prior to communication of the cylinder bore with the respective pressure port.