Patent ID: 6662558
Filing Date: 2003-12-16
Classification: F04B,F16D

Abstract:
A variable delivery control arrangement operative to control the volume of fluid being delivered to a work system, comprising:a fluid pump having an outlet port; a fluid delivery changing mechanism operatively associated with the pump, the fluid delivery changing mechanism has first and second fluid ports; a pressure reducing valve connected to the outlet port of the pump in parallel with the work system; an infinitely variable control valve arrangement disposed in a control conduit between the pressure reducing valve and the second fluid port of the fluid delivery changing mechanism, the infinitely variable control valve arrangement has first and second end portions; a first pilot conduit connected to the control conduit at a point upstream of the infinitely variable control valve arrangement and to both the first port of the fluid delivery changing mechanism and the first end portion of the infinitely variable control valve arrangement; a low pressure conduit connected to the control conduit between the pressure reducing valve and the infinitely variable control valve; an electrically controlled proportional valve disposed in the low pressure conduit; a flow restrictor disposed in the low pressure conduit upstream of the electrically controlled proportional valve; and a second pilot conduit connected between the second end portion of the infinitely variable control valve arrangement and the low pressure conduit at a point between the flow restrictor and the electrically controlled proportional valve.