Abstract: A power steering system for automotive vehicles includes devices for decreasing reaction force and for increasing assisting force applied to the steering wheel in cases where steering operation is performed while the vehicle is stopped. The device comprises a cut-off valve and a bias spring biasing the cut-off valve upwardly. The area of the upper surface of the cut-off valve is larger than that of the lower surface thereof. Therefore, the cut-off valve can move downwardly against the biasing force of the bias spring to block fluid communication between a fluid pressure source and chambers of a power cylinder when fluid pressure exceeding a predetermined value is applied to the upper and lower surfaces of the cut-off valve.

Abstract: A flow control passage fluidly interconnects an output flow passage and a return flow passage to bypass a control valve. A control valve operation modifying variable orifice is disposed in and partly defines the flow control passage. The control valve operation modifying variable orifice is variable in flow area in response to at least one of vehicle control factors other than steering torque. A fixed flow area orifice is disposed in and partly defines the flow control passasge at a location downstream of the control valve operation modifying variable orifice. The control valve has a plurality of steering torque responsive variable orifices and bypass passage means for bypassing at least one of the steering torque responsive variable orifices. A differential pressure passage provides communication between the upstream and downstream sides of the fixed flow area orifice. An actuator is disposed in and partly defines the differential pressure passage.

Abstract: A clamp includes an elastic member which comprises a generally U-shaped tube portion, two recessed portions which separately extend from the tube portion and are curved inwardly, and two gripping portions which extend from the respective recessed portions, two opposing clamp teeth each of which is mounted on the inner face of a respective gripping portion, and a fastener which urges the two gripping portions toward each other for tightening and contracting the tube portion and at the same time driving the two clamp teeth toward each other. An elongated pipe-like member runs through the tube portion of the elastic member. A portion of a damaged automobile is positioned between the two opposing clamp teeth, and then the gripping portions are tightened by the fastener so that as the elastic member of the clamp is secured on the elongated member a portion of a vehicle is gripped tightly between the clamp teeth.

Abstract: An actuator (7) for varying the degree of power assistance is connected with a main battery (8) through a first fuse (12) separate from a second fuse (13) which protects a controller (1) such as a microcomputer for controlling the steering effort in accordance with the vehicle speed and other variables. An emergency control means (14-18) is connected with the actuator for preventing the steering from becoming abnormally heavy or light when the controller is isolated from the main battery. The emergency control means keeps the steering moderate by using a backup battery or by limiting a current supplied to the actuator to a predetermined value.