Husco International, Inc.

Michael J Paik

Dwight B Stephenson

Peter A Jahnke

Raud A Wilke

Xiaolong Yang

Joseph Lawrence Pfaff

Dennis R Barber

Michael C Layne

Leif Pedersen

A distributed hydraulic system locates a control assembly, that has electrohydraulic valves and a electronic controller, adjacent the respective hydraulically powered actuator controlled by that assembly. The control assembly includes a manifold block with ports to that the pump, tank return and actuator fluid conduits connect. One or more pressure ports are provided on the manifold block at which to sense pressure at different locations therein. A controller housing, in addition to containing an electronic function controller, also contains a separate pressure sensor for each pressure port, and is mounted against the manifold block so that each pressure sensor connects to a pressure port. The manifold block also has a pair of exterior walls that extend on opposites sides of the controller housing to protect the electronic controller. Other features that facilitate distributing the hydraulic control adjacent the actuators are provided.

Integrated valve assembly and computer controller for a distributed hydraulic control system

Hydraulic valve manifold block

Electronic controller and hydraulic valve block assembly

A pilot operated valve has a poppet that is held against a valve seat by pressure in a control chamber on an opposite side of the poppet and by force from a feedback spring. The force feedback spring also engages a pilot valve spool which controls the flow fluid from a control chamber. When a electrically driven actuator moves the pilot valve spool and fluid is released from the control chamber, inlet pressure acting on the poppet causes the valve to open. As the poppet moves away from the valve seat, the feedback spring exerts more force on the pilot valve spool so as to meter the fluid being released from the control chamber. When the force of the feedback spring counterbalances the actuator force, an equilibrium condition occurs and the poppet stops moving at the desired flow control position.

Hydraulic poppet valve with force feedback

A pilot operated valve has a main poppet that selectively controls bidirectional flow of fluid between two ports in response to pressure in a control chamber on one side of the main poppet. The main poppet has a pilot orifice that is opened and closed by a pilot poppet. A unique mechanism is provided to compensate for variation of a pressure differential on opposite sides of the pilot orifice. This mechanism has a pair of annular end members between which extends a spring formed by a plurality of helices. Multiple passages with check valves extend through the main poppet to communicate the greatest pressure among the two ports to the control chamber and the lowest pressure among the two ports to the side of the pilot orifice that is opposite the control chamber.

Pilot operated control valve having a poppet with integral pressure compensating mechanism

A pilot operated valve is provided to control a bidirectional flow of fluid between two ports. A main poppet selectively controls flow of fluid between the ports in response to pressure in a control chamber on one side of the main poppet. A pilot passage in the main poppet extends between the second port and the control chamber A first pair of check valves allow fluid to flow only into the pilot passage from the two ports. A second pair of check valves allow fluid to flow only into the control chamber from the two ports.

Bidirectional pilot operated control valve

An improved pressure-compensated hydraulic system for feeding hydraulic fluid to one or more hydraulic actuators. A remotely located, variable displacement pump provides an output pressure equal to a control input pressure plus a constant margin. A pressure compensation system requires that a load-dependent pressure be provided to the pump input through a load sense circuit. An isolator transmits the load-dependent pressure to the pump control input, while preventing fluid from leaving the load sense circuit and flowing to the remotely located pump. A valve section, which controls the fluid flow between the pump and actuator, has a pressure compensating valve with a piston and spool controlling a pressure differential across a main control valve orifice by moving within a bore in response to a pressure differential between a pump supply pressure and the load sense pressure. The piston and spool also separate to shut off fluid flow to the actuator when the back pressure from the load exceeds the pump supply pressure.

Hydraulic control valve system with split pressure compensator

A manual override handle assembly for the operation of a hydraulic control valve of the type having a movable spool includes a housing forming a hollow chamber in which a spool extension is slidably mounted. A handle assembly extends outwardly from the housing and is mounted for pivotal movement within the chamber. The handle is movable to an inoperable position wherein the handle is disassociated from the spool extension so that movement of the spool extension will not result in movement of the handle. The handle is further movable to an operable position wherein the handle engages the spool extension so that movement of the handle results in movement of the spool extension.

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Delafield, WI, United States of America

Michael J Paik