| 摘要 |
1,152,266. Air brakes. WESTINGHOUSE BRAKE & SIGNAL CO. Ltd. 13 June, 1967 [20 June, 1966], No. 27449/66. Heading F2F. In a system where air supply lines 5, 7, Fig. 1, act respectively upon a " spring applied " brake actuator 2 and an " air-applied " brake actuator 3 both operating on a common brake (not shown) via rod 4, an interlock 9, 11, 12 is provided between the lines 5, 7 whereby, upon application of the brake by one actuator 3, operation of the other actuator 2 is at least partly inhibited. The interlock consists of a double check valve 9, a pressure regulating valve 11, and a one-way valve 12; the valves 11 and 12 being combined in one modification (Fig. 2, not shown) and all three valves being combined in a composite valve (9/11/12, Figs. 3, 4, not shown). Operation.-With line 5 under full pressure to release actuator 2, a rise in pressure in line 7 causes actuator 3 to apply the brake. The pressure in line 13 is less than the pressure in line 7 by an amount determined by the regulating valve 11, and is applied to check valve 9 which applies to the spring-applied actuator 2 the higher of the two pressure inputs 5, 13. Thus, if the pressure in line 5 falls, the actuator 2 cannot be operated by more than the amount determined by the pressure at 13. The valve 12 allows for release of pressure at 13 upon a pressure drop in line 7. Composite valve (Fig. 4, not shown).-One input (21) is connected to line 5, Fig. 1, and a second input (22) to line 14, the output (23) connected to the line 10 receiving one or other input pressure according to whether a valve closure member (27) rests on a first valve seat (25) or a second valve seat (24). The closure member (27) has two relatively slidable parts (28, 29) held together by a first spring (30), and the member is biased to normally close one input (22) by a second, stronger, spring (26) which provides the function of the pressure regulating valve. Increase of pressure at the second input (22) causes the slidable part (28) to close the first input (21) before the other slidable part (29) opens the second input (22). |
