| 摘要 |
<p>883,525. Valves. WEATHERHEAD CO. June 17, 1958 [July 26, 1957], No. 19413/58. Class 135. [Also in Group XXXII] In a pneumatic road wheel suspension, the valves 56, 156 controlling admission of pressure air to, and exhaust of air from, the pneumatic spring, are operated in dependence of change in vehicle height by the action of a lever 26 connected to the axle. Pipes 30 and 32 lead to a pressure reservoir and spring respectively. The lever 26 is coupled to rotate with a member 94 having a circularly-disposed, recessed cam track 125. Half of the periphery of the track 125 is of greater depth as shown at 124. The member 94 is axially movable relative to the main valve housing 34, and is outwardly urged by a spring 88 into a position in which the stems 66, 166, of the valves 56, 156, are out of engagement wih the track 125. Under pressure of air passing from the reservoir via the pipe 30 and conduits 72, 78, 84 and 82, to a chamber 106, the member 94 is urged against spring 88 into its normal position (Fig. 4). The track 125 is then in a position to lift one or other of the valves 56, 156 (according to the position of the lever 26). Thus, on failure of pressure in the reservoir, both valves 56, 156 are held in closed position by their springs 62, 162. Under this condition, back pressure acting from the spring via conduits 172 and 70 on the valve 56 also acts on a piston 54 rigid with the stem 66 of the valve 56 and having a larger area than the valve 56. The latter is thus held in closed position by the back pressure.</p> |
