Abstract: A pressure control valve is provided for controlling both the low and high pressure ranges of a variable displacement pump in addition to the pressure control valve used for adjusting the variable displacement member of the variable displacement pump.

Abstract: A power output control device for a pump having a delivery adjuster, is formed of a housing including a control piston attacked at one end with the output medium of the pump and having means for controlling the pump adjuster; a two-armed rocking lever is supported in the housing for movement parallel to the axis of the control piston, one arm of the lever being biased by a governor spring having a progressive biasing force while the other arm of the lever acts on the control piston against the force of pressure medium; an additional biasing spring thrusts against the other arm of the lever and a first setting screw adjusts the biasing force of the additional biasing means and a second setting screw adjusts the biasing force of the governor spring by adjusting the position of the pivot point of the two-armed rocking lever.

Abstract: A variable displacement rotary piston pump has a rotor splined to a driven shaft, a plurality of radially directed cylinders, each having a slidable piston fitted therein, a pumping ring surrounding the rotor and mounted eccentrically of the axis of the rotor with which the pistons maintain contact and are caused to move within the cylinders, a piston return ring engageable with notches formed on the pistons and an eccentric mounted for rotation to which the pumping ring is secured having an actuator pin whose movement determines the position of the pumping ring with respect to the rotor, thereby regulating the flow rate of the pump. The pump destrokes above the idle speed of the engine from which it is driven and limits the flow rate of the pump. A venturi orifice establishes a differential pressure which is applied across a flow control valve, which directs hydraulic fluid at discharge pressure to one or the other of two control pistons thereby adjusting the eccentric position.

Abstract: A vane-type variable displacement pump is controlled by a first stage servo-valve. The servo-valve is controlled by a second stage which may optionally include devices which provide any of several desired control effects.

Abstract: A hydraulic apparatus for changing flow rate by displacing the flow rate changing member of a variable displacement hydraulic pump accommodated in a casing for eliminating any surplus and leaked oil and diminished kinetic energy loss comprises an actuator, a flow rate control valve, a resilient member accommodated in the casing to urge the flow rate changing member toward the direction where the flow rate of the hydraulic pump is increased, first and second sliding members slidably received in first and second cylinder chambers, respectively, provided in the casing to urge the flow rate changing member toward the direction where the flow rate of the hydraulic pump is decreased, a first fluid conduit having one end connected with an outward port of the hydraulic pump and the other end connected with a rear port of the actuator, a second fluid conduit having one end connected with a fore port of the actuator and the other end connected with an inlet port of the hydraulic pump through the flow rate control valve

Abstract: An adjustable volume vane-type rotary pump is disclosed in which volume control is obtained by adjusting the eccentricity of a control ring against which the vanes run. The control ring is urged towards its position of maximum eccentricity by a spring and position control of the ring is obtained by a piston and cylinder system operating in opposition to the spring. Operation of the piston and cylinder assembly is dependent on the dynamic pressure of fluid delivered by the pump so that when a certain speed of rotation is achieved the pressure exerted by the piston and cylinder system will be sufficient to overcome the force of the spring and adjust the position of the control ring.

Abstract: In a sliding vane machine a work can be accomplished by a pressure fluid rotating a rotor provided with a plurality of sliding vanes, which function as turbine blades, whereby the work is taken out as a rotational motion at the rotor shaft. If the machine is designed as a pump the shaft is rotated and the vanes act as impeller blades.In both cases it is desirous if the machine can adapt its work in response to varying loads.In accordance with the invention this is achieved by providing the machine with pressure plates controlling the effective working area of said vanes, the pressure plates thereby being adjusted by a fluid pressure which by means of a pressure actuated valve can be varied the pressure-actuated valve itself being controlled by the fluid pressure in a conduit supplying the pressure fluid to the machine.

Abstract: A variable-output pump has an output-adjusting element which is acted upon by a differential piston arrangement having oppositely facing active surfaces of a smaller and of a larger active area. Control fluid is permanently admitted to the smaller active area of the differential piston arrangement to act on the same and urge the output-adjusting element of the pump toward a low-output position. A biasing spring acts against the force of the fluid acting on the smaller surface, and the control fluid is also selectively admitted to the larger surface to urge the adjusting element toward higher outputs. A control slide controls the admission of the control fluid to the larger surface of the differential piston arrangement and has a housing provided with a bore in which a slide is mounted for movement longitudinally of the bore. The slide has an end face acted upon by the control fluid and another end face acted upon by a spring.