Caterpillar Inc.

Caterpillar Tractor Co.

Edward L Stapleton

Wesley Thomas Payne

John B Waggoner

Christopher Michael Morency

Glenn G Smith

A hydraulic valve stack for a work machine is disclosed. The hydraulic valve stack has a base with a first mounting surface and a second mounting surface. The base is connectable to the work machine and has at least one fluid passageway extending through the base from the first mounting surface to the second mounting surface. The hydraulic valve stack also has a permanent valve assembly configured to control a permanent function of the work machine and an optional valve assembly configured to control an optional function of the work machine. The permanent valve assembly is connectable to the first mounting surface of the base, while the optional valve assembly is connectable to the second mounting surface of the base. Each of the permanent and the optional valve assemblies have at least one fluid passageway in communication with the at least one fluid passageway of the base.

Expandable hydraulic valve stack

Load sensing hydraulic systems conserve energy by generating only the fluid flow demanded by the system and at a pressure only slightly greater than the highest load pressure of the system. Optimizing the operating characteristics of the system for certain applications also caused the variable displacement pump to go to its maximum displacement setting with the excess fluid generated thereby not doing any useful work. The load sensing hydraulic system includes a flow control valve connected to a directional control valve and has an operating position in which fluid exhausted from a hydraulic jack is transmitted therethrough to a tank. A signal valve is disposed in a control pressure signal line for controlling fluid flow therethrough from a supply conduit to one end of the flow control valve. When the signal valve is blocking fluid flow through the signal line, the flow control valve is in the above-noted operating position. When the signal valve permits fluid flow through the signal line, the flow control valve is moved to a position to block fluid flow therethrough to the tank. The signal valve is connected to the directional control valve for movement therewith to establish the blocking or fluid transmitting positions.

Load sensing hydraulic system

The invention is concerned with an improvement in a hydraulic reservoir which comprises a tank having internally thereof filter means attached longitudinally between a first and a second generally parallel side thereof, said filter means including generally tubular filter element means extending generally longitudinally between said first and second sides of said tank and means for introducing a hydraulic fluid from an exterior of said tank to an interior of said element means from adjacent said first side of said tank. The improvement of the present invention comprises a tube within said tank surrounding said element means and extending longitudinally generally the length thereof, said tube including exit means therethrough through which said hydraulic fluid passes after passage thereof from the interior to an exterior of said element means; and means for compressibly sealing a first end of said tube adjacent said second side of said tank.

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Joliet, IL, United States of America

Edward L Stapleton