Fluid pressure operated servo-devices

Claim 1

A SERVO-DEVICE STRUCTURE COMPRISING A CYLINDER, A HOLLOW PISTON SLIDABLY DISPOSED THEREIN, AN END WALL AND A PLUG CLOSING OFF THE OPPOSITE ENDS OF SAID PISTON AND FORMING A HOLLOW CHAMBER, IN SAID PISTON, AN ANNULAR MEMBER SLIDABLY DISPOSED IN SAID MEMBER ADJACENT SAID END WALL, A FIRST BIASING MEANS NORMALLY URGING SAID ANNULAR MEMBER AWAY FROM SAID END WALL AND AGAINST SAID PLUG, SAID END WALL BEING OF SUBSTANTIALLY LARGER DIAMETER THAN THE REMAINING PORTION OF SAID PISTON EXTENDING TOWARD SAID PLUG, SAID PISTON PORTION FORMING AN ANNULAR SPACE WITH THE INNER SURFACE OF SAID CYLINDER, PASSAGE MEANS IN SAID PISTON IN COMMUNICATION WITH SAID SPACE AND SAID CHAMBER ADJACENT SAID END WALL, SAID ANNULAR MEMBER AND PLUG EACH HAVING A CENTRAL HEMISPHERICAL RECESS IN ADJACENT SIDES THEREOF AND FACING EACH OTHER AND PROVIDING SOCKET JOINTS, SAID END WALL HAVING A PORT THEREIN IN COMMUNICATION WITH SAID CHAMBER AND PASSAGE MEANS, A VALVE HOUSING PROJECTING OUTWARDLY FROM SAID END WALL AND ADJACENT SAID PORT, A SLIDABLE VALVE DISPOSED IN SAID HOUSING TO CLOSE OFF SAID PORT, A VALVE SEAT ON SAID END WALL ADJACENT SAID PORT, A SECOND BIASING MEANS NORMALLY URGING SAID VALVE SEATED ON SAID VALVE SEAT TO CLOSE OFF SAID PORT, FLUID SUPPLY MEANS IN SAID HOUSING FOR SUPPLYING FLUID UNDER PRESSURE TO SAID PORT AND PASSAGE MEANS AND ANNULARR SPACE WHEN SAID VALVE IS OPENED TO MOVE SAID PISTON IN SAID CYLINDER, AN OPERATOR ACTUATING ROD EXTENDING THROUGH SAID HOUSING, PORT AND ANNULAR MEMBER AND HAVING A BALL JOINT END ON ITS END FITTING INTO SAID ANNULAR MEMBER RECESS TO PROVIDE A UNIVERSAL JOINT, A SHOULDER ON SAID ANNULAR MEMBER ADJACENT SAID PORT ADAPTED TO UNSEAT SAID VALVE WHEN SAID ROD IS PULLED TO SUPPLY FLUID PRESSURE TO SAID ANNULAR SPACE AND PISTON PORTION ADJACENT SAID PLUG, ANOTHER ROD EXTENDING THROUGH SAID PLUG AND CYLINDER AND HAVING A BALL JOINT END ON ITS END FITTING WITHIN SAID PLUG RECESS TO PROVIDE A UNIVERSAL JOINT, SAID ANOTHER ROD BEING ADAPTED TO BE CONNECTED TO A BRAKE ACTUATING MEANS.