GB1382059A - Supplementary steering system for vehicles - Google Patents

Abstract

1382059 Supplementary hydraulic steering system TYRONE HYDRAULICS Inc 29 Dec 1971 60515/71 Heading B7H A vehicle steering control system has a supplementary hydraulic supply apparatus which includes a reversible rotary pump 47 having chambers at opposite sides of the pump serving either as suction or pressure chambers according to the direction of rotation of the pump, with valve means 49 for delivering fluid from an input port to the operational suction chamber and for delivering fluid to the output port from the operational pressure chamber, and a movable valve member allowing communication between the operational pressure chamber and the output port while closing communication between the operational suction chamber and the output port. As shown in Fig. 1, the direction of rotation of the pump 47 which is supplementary to the primary pump 43 driven by the vehicle engine 14 is dependent upon the direction of movement of the vehicle. The pump 47 is preferably of the well known gear type, Fig. 2, including upper and lower gears 51, 53 which mesh and separate the interior of housing 55 into first and second chambers (55<SP>1</SP>), (55<SP>11</SP>), Fig. 5 (not shown). The valve assembly 49 includes passage 84 connecting inlet port 77 with outlet port 81 via passage 87 which communicates also with chamber (55<SP>1</SP>) via port 73. A similar arrangement occurs on the other side of shaft 57. With counterclockwise rotation of shaft 57 a suction is first felt in passage 87 through port 73 and then behind valve member 101 via port 115 to cause the valve member 101 to move to the left against spring 113; thus allowing fluid from the inlet port 73 supplied from tank 45 to flow into pump 47 via passage 87 and port 73 to be transferred to the pressure side of the pump and out through port 75 into the passage 89. From thence the fluid causes shuttle valve member 141 to move to the left against seat 131 and to block flow back to passage 87 and allow flow through passage 91 into the steering valve 35. Pressure in the meantime, is applied behind valve member 101<SP>1</SP> via port 115<SP>1</SP> to keep the valve in a closed position. It will be understood that fluid will be delivered in the same direction to outlet port 81 with clockwise rotation of the shaft 57.