Patent GB-808659-A (GB)
Title: Improvements in the control of inflation pressure in the tyres of a vehicle when thevehicle is at rest or in motion
Inventor: DIXON MARGARET GULLAND
IPC: B60C23/00
Filed: 1956-01-12
Abstract: 808,659. Controlling tyre inflation. SCOVILL MANUFACTURING CO. Jan. 12, 1956, No. 1139/56. Class 144 (2). [Also in Group XXIX] In a system for controlling the inflation pressures of any or all of the tyres of vehicle whilst the vehicle is stationary or in motion, a source 69 of fluid under pressure is connected (1) via a conduit 81 and a normally closed pilot-operated valve 82 to the tyres; (2) via a conduit 77 to the inlet of a pressure regulator valve 79; and (3) via conduits 105, 115, to the inlet port 60 of a shuttle valve C, Fig. 6, the outlet 61 of which is connected via a conduit 125 with the pilot of the valve 82, and the two ends 66 of which are connected respectively via a conduit 103 to the outlet of the regulator valve 79 and via a conduit 97 to a pressure-control tank 96 which is in communication with the tyres, there being means, such as normally closed pilot-operated valves 104, 100, in said conduits 103 and 97 to control the application of the pressures from the regulator valve 79 and the control tank 96 to the opposite sides of the shuttle of the valve C to operate said shuttle and thereby cause operation of the pilot of valve 82 and admit pressure fluid from the source 69 to the tyres. Fig. 1 shows a schematic layout for a military vehicle, each of the wheels of which is fitted with a rotary connection of the form described with reference to Fig. 5 of Specification 729,954. Each said rotary connection comprises a check valve-unseating member operable by pressure fluid conducted thereto via conduits 26, and a pressure chamber placed in communication with the tyre by unseating of the check valve and connected via conduits 29 to a manifold 85 fed from the valve 82. In operation, if it is desired to increase the inflation pressure of the tyres from say 10 p.s.i. to 40 p.s.i., an equalizer valve 78 in the conduit 77 is opened to allow line pressure from the source 69 to pass via conduits 105 and 107<SP>1</SP> to a manifold 108 supplying the conduits 26 to effect unseating of the check valves in the rotary connections. The tyres are thereby placed in communication, via conduits 29, manifold 85, conduit 87, a normally closed pilot-operated valve 88 (now open by operation of its pilot via conduit 107), a normally open pilot-operated valve 93, and a conduit 94, with the pressure-control tank 96 to equalize the pressures in the tyres and the tank 96 at the present state of 10 p.s.i. A spring- loaded operating valve 133 supplied with pressure fluid from the equalizer valve 78 is then manually operated and held open for about two seconds. Line pressure is thereby applied through conduits 134, two three-way pilotoperated valves 112, 113 connected in series by a conduit 114, and a conduit 115 to a branch 116 supplying, via conduits 117, 122 the inlet port 60 of the shuttle valve C, and via conduits 120, 121 the pilots of the valves 104, 100. Also from branch 116 line pressure passes via conduit 119 to operate the pilot of normally open valve 93 to close same. This confines flow from the tyres to the tank 96 through a flowcontrol valve 91 and a restricted orifice 92. Operation of the pilots of valves 104, 100 subjects opposite sides of the shuttle in valve C respectively to pressures of 40 p.s.i. via conduit 103 from the previously set regulator valve 79, and 10 p.s.i. via conduit 97 from the control tank 96. This causes movement of the shuttle to the right to allow line pressure from inlet 60 to pass via outlet 61 to operate the pilots of valves 113 and 82. Operation of valve 113 shuts off line pressure flow through conduit 114 but permits it instead through conduit 111 to render the subsequent inflation operation independent of operation of the valve 133. Operation of valve 82 applies line pressure from conduit 81 to the manifold 85 and thence to the tyres and also via conduit 87 and the restricted orifice 92, to the tank 96. The orifice 92 permits flow of fluid at the same rate as the tyre inflation valves so that the pressures in the tyres and the tank are at all times the same. When the tyre pressure, and therefore the pressure on the righthand side of the shuttle, has built up to the desired 40 p.s.i., the shuttle is moved back to shut off outlet 61 and permit exhaust of the pilots of valves 113 and 82 through their respective quick exhaust valves 127 and 131, and exhaust of the conduits 125, 126 to said pilots, through an exhaust port 64 of the valve C. This effects shut off of line pressure to the shuttle valve C and to the tyres. The respective pressures shown by the regulator valve gauge 80 and the control tank gauge 102 will now read the same. For deflation of the tyres the operation is the same, but since the regulator control valve pressure will now be less than the control tank pressure, the shuttle of valve C is moved to the left to connect line pressure to shuttle outlet 62. Outlet 62 feeds the pilots of valve 112, to effect by-pass of valve 133, and the pilot of an exhaust valve 84 connected to the manifold 85. This time pressure fluid flows from the tank 96 through the restricted orifice 92, and with further restriction through the valve 91 to exhaust with the tyres until the pressure in the tank 96, and therefore at the right-hand side of the shuttle, equals that selected by the regulator valve 79. Valves 86 in the conduits 29 permit selective control of the various tyres. In normal use the equalizer valve 78 is kept permanently open. In an alternative arrangement, for use with rotary wheel connections, either as described with reference to Fig. 4 of Specification 729,954 or as described in Specification 450,977, the manifold 108, the pilot-operated valves 88, 93 and the equalizer valve 78 are omitted. In all other respects the arrangement is the same. In both systems the shuttle valve C is the same (see Group XXIX).