Vehicle steering system

Claim 1

IN COMBINATION WITH A GANTRY-TYPE VEHICLE HAVING SPACED SIDES AND A CONNECTING BRIDGE DEFINING A GENERALLY U-SHAPED FRAME AND A PAIR OF WHEEL SUPPORT BRACKETS MOUNTED ON SAID FRAME AT OPPOSITE SIDES OF THE VEHICLE FOR TURNING MOVEMENT ABOUT AN UPRIGHT AXIS, A PAIR OF HYDRAULIC STEERING BOOSTERS EACH INCLUDING A CYLINDER, A PISTON IN THE CYLINDER, AND A CONTROL VALVE CONNECTED TO THE CYLINDER FOR MOVEMENT THEREWITH AND FOR REVERSIBLY CONTROLLING THE FLOWS OF FLUID TO THE RESPECTIVE CYLINDER, MEANS PIVOTALLY CONNECTING THE CYLINDER AND VALVE OF EACH BOOSTER TO A RESPECTIVE ONE OF THE STEERING WHEEL BRACKETS AT A POINT SPACED HORIZONTALLY FROM THE PIVOT AXIS THEREOF, MEANS PIVOTALLY CONNECTING EACH PISTON ROD TO THE FRAME OF THE VEHICLE TO EFFECT TURNING OF THE WHEEL BRACKETS IN RESPONSE TO EXTENSION AND RETRACTION OF THE BOOSTERS, SAID CONTROL VALVES EACH INCLUDING A VALVE OPERATOR MOVABLE RELATIVE TO THE VALVE IN OPPOSITE DIRECTIONS FROM A NEUTRAL POSITION TO REVERSIBLY CONTROL THE FLOWS OF FLUID TO THE RESPECTIVE CYLINDER, LINKAGE MEANS CONNECTING SAID VALVE OPERATORS AT OPPOSITE SIDES OF THE VEHICLE TO EFFECT TURNING OF THE STEERING WHEEL BRACKETS IN CONTROLLED RELATION TO EACH OTHER, SAID LINKAGE MEANS INCLUDING AN UPRIGHT STEERING SHAFT MOUNTED AT EACH SIDE OF THE VEHICLE FOR ROTATION ABOUT AN AXIS PARALLEL TO THE PIVOT AXIS OF THE WHEEL BRACKET AT THAT SIDE OF THE VEHICLE, FIRST AND SECOND ARMS ON EACH SHAFT, A TIE BAR EXTENDING CROSSWISE OF THE VEHICLE AND PIVOTALLY CONNECTED TO SAID FIRST ARMS AT EACH SIDE OF THE VEHICLE, AND MEANS CONNECTING SAID SECOND ARMS AT EACH SIDE OF THE VEHICLE TO THE VALVE OPERATOR AT THAT SIDE OF THE VEHICLE.