GB497843A - Improvements in or relating to valves for hydraulic systems - Google Patents

Abstract

497,843. Hydraulic valves. INDIA RUBBER, GUTTA PERCHA, & TELEGRAPH. WORKS CO., Ltd., TARRIS, F. J., and WEBB, D. June 25, 1937, No. 17711. [Class 135] A control device for producing two differentially adjustable hydraulic pressures comprisies a pair of valves each comprising one or more movable elements controlling the communication between inlet and outlet ports 134, 152 and subject to the pressure regulated by the valve and to an independent fluid loading pressure acting in opposition to the said regulated pressure, means being provided to effect differential adjustment of the independent loading pressures. In Figs. 1, 2, two similar regulating valves are arranged in parallel relationship in a single casting 120. Each valve comprises a liner 131 with inlet ports 134, outlet ports 152 and exhaust ports 153, the inlet and exhaust ports being controlled respectively by piston portions 130, 137 on the movable element. The ports 152 are opposite a reduced portion 136 of the movable element and are connected by a passage 127 with a conduit 36 or 37 leading to the brake mechanism on opposite sides of the fore-and-aft line of an aircraft. The movable element has a central bore 160 and lateral ports 138 so that its upper face is always subject to the pressure obtaining in the outlet ports 152. The sets of ports 134 communicate by annular channels 151 with a passage 150 connected to a conduit 38 leading to a pump or other source of fluid pressure. The ports 153 communicate by passages 139 with a conduit 42 leading back to the pump or to a reservoir. The movable element is loaded by a light spring 133, but this may be omitted. The spring abuts a removable screw cap 132 which holds the liner 131 in place. The piston 137 is loaded on its lower side by fluid pressure admitted by a conduit 118 or 119 from a bore 114 containing a piston valve 122 with chamfered ends. The ends of the bore are connected by passages 116, 117 with a pressure supply conduit 32 having a control valve (not shown). The valve 122 is connected by a link 39 with the rudder bar of the aircraft so that the two regulating valves and the respective brakes are differentially controlled. A restricted port 141 is provided to connect the conduits 32 and 42 whereby the fluid is constantly circulated. The dimensions of the valve may be such that the exhaust ports are not opened until the originally applied loading pressure is removed. Specifications 488,489 and 493,440 are referred to.