Patent ID: 8899034

Claim:
A control valve assembly for a hydraulic system in which a variable displacement pump sends fluid, drawn from a tank, into a supply conduit, and wherein the hydraulic system has a plurality of hydraulic actuators, the control valve assembly comprising: a flow summation node; a first supply node connected by a first passageway to the flow summation node; a second supply node; a first element defining a second passageway between the flow summation node and the second supply node and restricting fluid flow to a greater degree than restriction of fluid flow through the first passageway; a first control valve and a second control valve, each having a variable first path, a variable second path, and a variable third path; wherein the variable first paths of both the first and second control valves are connected in parallel to form a variable flow section through which fluid flows between the variable displacement pump and the flow summation node, fluid selectively flows through the variable second path of the first control valve between with the first supply node and a first hydraulic actuator, fluid selectively flows through the variable second path of the second control valve between with the second supply node and a second hydraulic actuator, and the variable third paths of both the first and second control valves are connected in series to form a bypass passage through which fluid flows between the flow summation node and the tank; and a first priority check valve through which fluid flows only in a direction into the second supply node from a point in the bypass passage that is between first and second control valves.