Abstract: A control apparatus controls the hydraulic connection between self steering wheels on a trailing vehicle, for example a grain cart, and the hydraulic system of a utility vehicle, for example a tractor, towing the trailing vehicle. An auxiliary circuit on the trailing vehicle forms a continuous loop receiving in series one or more wheel actuators associated with the self steering wheels. A valve arrangement is operable in a locked state or unlocked state in which the continuous loop is isolated from the tractor to prevent or allow a flow of fluid in the continuous loop regardless of the state of the tractor hydraulics. In a manual state, the flow in the loop is dependent upon the tractor hydraulics. In an automatic mode, a controller automatically operates the valve arrangement between the locked and unlocked states dependent upon one or more sensed operating conditions of the trailing vehicle.

Abstract: A control apparatus controls the hydraulic connection between self steering wheels on a trailing vehicle, for example a grain cart, and the hydraulic system of a utility vehicle, for example a tractor, towing the trailing vehicle. An auxiliary circuit on the trailing vehicle forms a continuous loop receiving in series one or more wheel actuators associated with the self steering wheels. A valve arrangement is operable in a locked state or unlocked state in which the continuous loop is isolated from the tractor to prevent or allow a flow of fluid in the continuous loop regardless of the state of the tractor hydraulics. In a manual state, the flow in the loop is dependent upon the tractor hydraulics. In an automatic mode, a controller automatically operates the valve arrangement between the locked and unlocked states dependent upon one or more sensed operating conditions of the trailing vehicle.