Abstract: An AND-type control valve useful in a vehicle braking system to prevent application of the vehicle brakes when only the right-hand or left-hand vehicle brakes are applied for the purpose of steering the vehicle. The control valve has two input flowpaths corresponding to the hydraulic braking circuit on different sides of the vehicle and a control output port for connection to the vehicle brake valve. Each input flowpath contains a non-return valve having associated therewith a flow sensitive device to provide a restricted flowpath which gives rise to a pressure drop which will tend to close or assist in closure of the non-return valve. A device is provided to prevent simultaneous closure of both non-return valves.

Abstract: A control system for operating a double-acting hydraulic ram or motor, including a proportional meter-out type directional-control valve which meters the flow of fluid out of the load and, in association therewith, a combined flow and pressure-control valve in the return line from the load. The flow and pressure-control valve is responsive to the pressure drop across the meter-out orifice of the directional-control valve such that return-line flow is restricted at high pressure drops and the supply pressure to the load is increased at low pressure drops, whereby a substantially constant pressure drop across the meter-out orifice is maintained irrespective of the size or direction of the load.

Abstract: A hydraulic ram system for tilting a vehicle cab which is resiliently mounted on the vehicle frame includes a ram cylinder of which that end in which the ram piston is located when the cab is in the lowered position is of increased bore diameter to render the piston passive in this position, a restriction being provided in the lower ram line across which a pressure drop is created when fluid is pumped through the line, while in the upper ram line a valve is provided responsive to the pressure differential across the restriction and thereby operable to interconnect the upper and lower ram lines.