Electrically controlled valves

A valve, said valve having a body formed so as to include separate pressure and return chambers, separate first and second load passages, each of said passages extending between and terminating in an opening in each of said chambers, a pressure port leading into said pressure chamber, a return port leading from said return chamber, first and second load ports connected to said first and second load passages, respectively, actuator means extending into said chambers for controlling the flow of fluid from said pressure port through said openings in said pressure chamber into each of said load passages for controlling the flow of fluid from said openings in said return chamber from said load passages to said return port in which the improvement comprises:

• said actuator means comprising a member mounted on said body so as to extend into each of said chambers in such a manner that said chambers are isolated from one another,
• said member being capable of being electrically actuated so that the portion of it within said pressure chamber and the portion of it within said return chamber are concurrently moved relative to said openings in said chambers upon the application of an electric signal so as to permit increased flow to either one of said passages from said pressure chamber and concurrently to restrict the flow from such passage into said return chamber while concurrently restricting the flow into the other of said flow passages from said pressure chamber and increasing the flow from such other passages into said return chamber,
• said member is an elongated member held at its center by said body so that equal amounts of said member located at the ends of said member extend into each of said chambers,
• said actuator means is a piezoelectric bender strip mounted on said body so that one end of said strip extends into one of said chambers and the other end of said strip extends into the other of said chambers, said body engaging said strip so as to isolate said chambers from one another.