A check valve is provided to each discharge port, which communicates between a corresponding working chamber and a high pressure chamber in an integrated compressor/expander apparatus. A valve mechanism, which is opened in a motor mode, is provided to communicate between the working chamber and the high pressure chamber.

Fluid machine operable in both pump mode and motor mode and waste heat recovering system having the same

A variable displacement pump having a tiltable swash plate including a pair of servo mechanisms for controlling discharge of pump fluid includes a zero displacement positioner for automatically returning the pump swash plate to a central, neutral position to discontinue pumping action if pump pressure is lost or if linkage controlling one of the servo mechanisms should break or otherwise fail.

Reversible, variable-displacement piston pump with positioner means for automatic return to zero displacement

A hydraulic system for a vehicle that includes an implement such as a bucket that is operated by a hydraulic actuator and a directional valve which controls flow from a load sensing variable displacement pump. A hydraulic bucket shake circuit is provided which is selectively operable to force the pump to a maximum displacement condition thereby providing standby pressure and flow to the directional valve so that the directional valve can be operated rapidly in order to shake the bucket and dislodge mud, clay and debris from the bucket or to allow penetration into frozen ground.

Hydraulic circuit for shaking a bucket on a vehicle

The invention is concerned with an improvement in a pump having a pump body, a swash plate the rotational position of which controls the displacement of the pump and means mounting the swash plate for rotation about an axis generally centrally thereadjacent. The improvement serves to control the pump output. In a broad sense, the improvement comprises means internal of said pump body and acting between said pump body and said swash plate for biasing the swash plate towards a zero displacement position corresponding to a minimum displacement of the pump, and means responsive to discharge pressure of the pump reaching a first magnitude for overriding the biasing means and rotating the swash plate towards a full displacement position corresponding to a maximum displacement of the pump said overriding means comprising servo valve means within said pump body and pilot pump means acting to initially shift said servo valve means to allow discharge pressure to be applied in opposition to said biasing means.

Pilot operated pressure compensated pump control

A variable capacity hydraulic machine has a rotating group located within a casing and a control housing secured to the casing to extend across and seal an opening in the casing. The control housing accommodates a control circuit and a pair of sensors to sense change in parameters associated with the rotating group. One of the sensors is positioned adjacent the barrel on the rotating group to sense rotational speed and the other senses displacement of the swashplate. The control housing accommodates a control valve and accumulator to supply fluid to the control valve.

Rotary hydraulic machine and controls

An override control, for a variable displacement pump having an actuator system which shifts the pump between a maximum displacement condition and a minimum displacement condition with the actuator system having a control device responsive to a primary source of pressurized fluid which is dependent upon operation of a prime mover drivingly connected to the pump, including a passage in communication with the actuator system and a secondary source of pressurized fluid selectively connectable to the passage and operable independently of the prime mover to override the control device causing the actuator system to shift the pump to one of the extreme displacement conditions.

V Hendrickson

Papers

Override control for a variable displacement pump