Patent ID: 6192936
Filing Date: 2001-02-27
Classification: B62D,F15B,Y10T

Abstract:
A hydraulic control device comprising:a main hydraulic valve adapted to provide a hydraulic output pressure;a pilot pressure control valve in fluid communication with the main hydraulic valve and configured to control the output pressure of the main valve such that an increase in operating pressure of the pilot valve causes a decrease in the output pressure of the main valve, wherein the pilot valve includes a closure member;a biasing member engaging the closure member of the pilot valve;a manually operable member movable to at least three positions to vary the operating pressure to at least three levels and thereby inversely control the output pressure of the main valve between at least three corresponding levels, wherein said inverse control is provided by the manually operable member acting on the biasing member;wherein the operating pressure of the pilot valve is controlled by the manually operable member imparting movement to the pilot valve;wherein the pilot valve and manually operable member are configured such that, when the manually operable member is in a rest position in the absence of manual control, a net force urges the pilot valve to an open position so as to allow fluid to flow freely past the pilot valve to thereby create minimum operating pressure of the pilot valve and maximum output pressure of the main valve; andwherein manual movement of the manually operable member away from the rest position imparts movement to the pilot valve toward a closed position to thereby increase the operating pressure of the pilot valve and decrease the output pressure of the main valve.