Variable ratio power steering gear

Claim 1

IN A POWER STEERING GEAR, A SOURCE OF FLUID UNDER PRESSURE, A HYDRAULIC MOTOR HAVING A CYLINDER, A PISTON RECTILINEARLY RECIPROCABLE THEREIN, AND A MOVABLE OUTPUT MEMBER OPERATED BY SAID PISTON AND ADAPTED FOR OPERATIVE CONNECTION TO A STEERED ELEMENT OF A VEHICLE, A ROTATABLE CAM HAVING A PORTION RECEIVED IN AN AXIALLY EXTENDING BORE IN SAID PISTON, SAID CAM BEING PROVIDED WITHIN THE PISTON WITH A HELICAL GROOVE HAVING PORTIONS OF DIFFERENT PITCH-ANGLE, A CAM FOLLOWER MOUNTED IN SAID PISTON AND HAVING AN END PORTION EXTENDING INTO SAID GROOVE TO PRODUCE RELATIVE AXIAL MOVEMENT OF THE CAM AND PISTON WHEN THE CAM IS ROTATED IN THE PISTON, SAID END PORTION HAVING AN OUTER SURFACE WHICH IS A SURFACE OF REVOLUTION WHOSE AXIS IS PERPENDICULAR TO THE PATH OF PISTON RECIPROCATION, SAID CAM HAVING A LIMITED RANGE OF AXIAL MOVEMENT RELATIVE TO THE HOUSING AND BEING MOVABLE WITHIN SUCH RANGE AS A RESULT OF THE AXIAL COMPONENT OF REACTION IMPRESSED UPON IT BY SAID CAM FOLLOWER, AND VALVE MEANS CONTROLLING THE FLOW OF FLUID UNDER PRESSURE FROM SAID SOURCE TO SAID MOTOR, SAID VALVE MEANS BEING RESPONSIVE TO AXIAL MOVEMENTS OF THE CAM.