Split system control valve for fluid pressure servomotors

Claim 1

A VALVE MEANS OPERABLE BY SINGLE AND MULTIPLE INPUT FORCES COMPRISING: A HOUSING INCLUDING A VALVE CHAMBER AND A LONGITUDINAL BORE; A FIRST PISTON IN SAID LONGITUDINAL BORE HAVING SEAL MEANS AT BOTH ENDS THEREOF TO PREVENT COMMUNICATION OF FLUID FROM ONE SIDE OF SAID PISTON TO THE OTHER SIDE OF SAID PISTON; A SECOND PISTON IN SAID BORE AHEAD OF SAID FIRST PISTON AND OPERATIVELY CONNECTED TO SAID FIRST PISTON SO AS TO BE RELATIVELY MOVABLE WITH RESPECT TO SAID FIRST PISTON AND CONTROLLABLE BY SAID FIRST PISTON, SAID SECOND PISTON HAVING A SEAL MEANS FOR PREVENTING FLUID LEAKAGE BY SAID SECOND PISTON MEANS; A VALVE IN SAID HOUSING OPERATIVELY CONNECTED TO SAID FIRST AND SECOND PISTONS FOR CONTROLLING COMMUNICATION OF A REFERENCE FLUID PRESSURE AND A CONTROL FLUID PRESSURE TO A VALVE CONTROL PORT IN SAID HOUSING, SAID VALVE INCLUDING, A FIRST VALVE SEAT FORMED ON SAID HOUSING, A PLUNGER SLIDABLY GUIDED BY SAID HOUSING AND HAVING A SECOND VALVE SEAT ON THE FORWARD END THEREOF WHICH IS ARRANGED IN SAID HOUSING TO THE REAR OF SAID FIRST VALVE SEAT SO AS TO BE MOVABLE TOWARDS SAID FIRST VALVE SEAT, SAID PLUNGER INCLUDING A REARWARDLY PROJECTING STEM OPERATIVELY CONNECTED TO SAID SECOND PISTON MEANS IN SAID LONGITUDINAL BORE, SAID PLUNGER ALSO HAVING A LONGITUDINAL PASSAGE THERETHROUGH, A POPPET MEANS COMPRISING AN ANNULAR SURFACE FOR ABUTMENT WITH SAID FIRST VALVE SEAT AND A SECOND SURFACE OPERATIVELY CONNECTED TO SAID ANNULAR SURFACE ARRANGED TO BE ABUTTED BY SAID SECOND VALVE SEAT AS IT MOVES IN A DIRECTION OF SAID FIRST VALVE SEAT, SAID SECOND SURFACE BEING SPRING BIASED TO THE REAR OF SAID FIRST SURFACE AND BEING OPERATIVELY CONNECTED TO A SPOOL VALVE ADAPTED TO CONTROL AN OPENING THROUGH THE FIRST ANNULAR SURFACE, SAID SECOND SURFACE AND SAID SECOND VALVE SEAT BEING CONSTRUCTED SO AS TO ABUT ON AN ANGLE WITH RESPECT TO A PLANE PASSING THROUGH THE ABUTMENT OF SAID FIRST ANNULAR SURFACE ON SAID FIRST VALVE SEAT OF SAID HOUSING, AND A MEANS BIASING SAID PLUNGER SO THAT SAID SECOND VALVE SEAT IS NORMALLY NOT IN CONTACT WITH SAID SECOND SURFACE SO THAT REFERENCE PRESSURE IS COMMUNICATED TO SAID VALVE MEANS VIA SAID PASSAGE THROUGH SAID PLUNGER AND SAID CONTROL PRESSURE IS PREVENTED FROM COMMUNICATION TO SAID VALVE CONTROL PORT BY SAID VALVE MECHANISM.