1355658 Power assisted steering CAM GEARS Ltd 7 Oct 1971 [16 Oct 1970] 49317/70 Heading B7H A power assisted vehicle steering system includes a unitary assembly 7, consisting of a torque responsive valve device and a double-acting rotary servomotor controlled by the valve device, interposed in the torsional transmission between the steering wheel 1 and the steering box 6. As described the steering wheel 1 is connected to a shaft 2 which is connected by bevel gears 3 to a shaft 4 which forms the input to the valve. The valve may be a rotary valve of the type described in Specification 1,022,029 which includes a torsion bar coupling which transmits the whole of the driver's torque in the absence of hydraulic pressure. The valve controls the flow of pressure fluid from a pump 10 to the servomotor, e.g. a gear type motor. The unit 7 is anchored at 7A to a frame or chassis part. The output of the servomotor is connected by a universal joint 5A to a shaft 5 which is connected to the steering box 6. A non-assisted steering system may be converted to a power assisted system by incorporating the unit 7 in the steering column, provided that there is a hydraulic pump to supply the unit 7.