Leveling control for vehicle suspension

Claim 1

IN A VEHICLE, HAVING A FRAME, A PAIR OF WHEELS ON OPPOSITE SIDES OF SAID FRAME, THE IMPROVEMENT WHICH COMPRISES A VEHICLE SUSPENSION SYSTEM COMPRISING A BEARING MEMBER ON EACH SIDE OF THE VEHICLE, MEANS MOUNTING SAID PAIR OF WHEELS FOR VERTICAL MOVEMENT UNDER CONTROL OF A RESPECTIVE ONE OF THE BEARING MEMBERS, FOR EACH BEARING MEMBER MEANS COMPRISING A CYLINDER COMPRISING A FLUID-ACTUATED PISTON FOR VARYING THE VERTICAL HEIGHT BETWEEN THE AXIS OF ROTATION OF THE INDIVIDUAL WHEELS AND SAID FRAME, EACH PISTON HAVING A DOWNWARDLY EXTENDING CONNECTING ROD CONNECTING EACH PISTON TO A RESPECTIVE BEARING MEMBER, FIXED GUIDE MEANS ON SAID FRAME FOR GUIDING THE UP AND DOWN MOVEMENT OF SAID BEARING MEMBERS, UPRIGHT GUIDE MEMBERS RECEIVED IN SAID GUIDE MEANS ON SAID FRAME FOR AXIAL MOVEMENT THEREIN VERTICALLY FOR GUIDING THE VERTICAL TRAVEL OF SAID BEARING, MEMBERS, SENSING MEANS FOR SENSING OF DEVIATIONS OF SAID FRAME FROM A HORIZONTAL POSITION, AND MEANS COMPRISING A SINGLE DISTRIBUTOR VALVE ACTUATED BY SAID SENSING MEANS FOR DISTRIBUTING FLUID UNDER PRESSURE TO BOTTOM OF SAID CYLINDERS INDIVIDUALLY AND ONLY ALTERNATIVELY IN DEPENDENCE UPON WHICH BEARING MEMBER IS TO BE LOWERED RELATIVE TO SAID FRAME TO MAINTAIN SAID FRAME HORIZONTAL.