Patent ID: 7614335
Filing Date: 2009-11-10
Classification: E02F,F15B,Y02P,Y10T

Abstract:
1. A method of operating a hydraulic system comprising: directing pressurized fluid from a source toward a plurality of first valves, each first valve having a housing and a spool reciprocating within the housing defining at least first and second valve positions; directing pressurized fluid from each of the plurality of first valves toward a plurality of second valves, each second valve being operatively associated with one of the plurality of first valves, when each of the plurality of first valves is in a first valve position, the plurality of second valves each having a variable flow area controllable from a substantially closed position to a fully opened position; directing pressurized fluid from the at least one second valve toward a source of low pressure as a function of the variable flow area; directing pressurized fluid from one of the plurality of first valves to an operatively associated actuator when one of the plurality of first valves is in a second valve position; and closing each of the plurality of second valves in response to one of the plurality of first valves moving to a second position.