Abstract: The steering system of a motor vehicle includes a steering motor having the application of pressurized fluid applied thereto by a main loop and in the event of a fault in the main loop by an auxiliary loop with the main loop isolated from the auxiliary loop. The motor includes a first and a second chamber. A first change over valve is fluidly connected to the first chamber of the motor while a second change over valve is fluidly connected to the second chamber. During normal operation the steering wheel is connected through a change over device to the main loop but in the event of a main loop fault, connected through said device to the auxiliary loop. Each loop includes a pump fluidly connected to a steering unit which is fluidly connected by one motor line connected to the first change over valve and a second motor line fluidly connected to the second change over valve.

Abstract: The steering system of a motor vehicle includes a two chamber steering motor having the application of pressurized fluid applied thereto through change over valves in one position by the way of a by pass valve and alternately in a second position by the way of a steering unit. The change over valves are operated from their first position to their second position upon activation of the steering unit which results in control valve moving from a position applying pressurized fluid from a pump to the by pass valve to a position applying pressurized fluid from the pump to the steering unit.

Abstract: A double acting hydraulic shock absorber is connected across first and second fluid conduits that are connected to opposite ends of hydraulic steering motors of an articulated vehicle and to a control unit that is controlled by a steering wheel to control the direction of movement of the vehicle. A pump provides pressurized fluid to the control unit. The shock absorber has a response pressure of a predetermined value and includes a piston in a tubular housing intermediate portion. A first shank is joined to the piston to abut against a first closure that closes one end of the housing to limit movement from the piston's datum position and a second shank joined to the piston to abut against a second closure that closes the opposite end of the housing to limit movement from the datum position toward the second closure.

Abstract: A pressure limiting valve including a body having an inlet and an outlet coaxially arranged at opposite ends of the body. A discharge passage is disposed in the body between the inlet and outlet. A cylindrical valve element is spring biased to a position to prevent communication between the inlet or outlet and the discharge passage. The valve element includes areas at opposite ends with one area being larger than the other so that pressure in the inlet and outlet act on the valve in a direction opposite the spring bias so as to open the inlet and outlet to the discharge passage upon a predetermined increase in pressure.

Abstract: The invention relates to hydrostatic steering control apparatus of the type having a hydrostatic steering motor which is connected to wheels to be steered and a steering wheel controlled metering or quantity setting device for controlling the hydraulic fluid supplied to the steering motor. A hydraulic amplifier connected to the steering motor has the characteristics of generating and transmitting undesired pressure pulses to the steering motor during steering switching operations. One way pre-stressed check valves are disposed respectively between the quantity setting apparatus motor ports and the steering motor ports. The check valves open in the direction of the steering motor ports and operate to allow bypassing the amplifier during the steering switching operations.

Abstract: The invention relates to a hydrostatic steering device having a servomotor connectable to wheels to be steered. The travel limits of the servomotor are sensed with position sensors which function to operate a locking apparatus which mechanically prevents further turning of the steering wheel upon a travel limit being reached in either direction.