| 摘要 |
1534253 Pneumatic brake systems for trailers WABCO WESTINGHOUSE GmbH 3 June 1977 [11 June 1976] 23583/77 Heading F2F The system has service and auxiliary brake circuits with respective reservoirs 46, 36 and respective relay valves 21, 8 between those reservoirs and the corresponding service and auxiliary (spring-applied) cylinders 20, 29, valve 8 having three control chambers 15, 16, 17 connected respectively to the service brake cylinders 20, the brake control line 24 and the outlet of a manually operable on/off valve 9 whose inlets 1, 2 are connected to the supply line 27 and the reservoir 36 respectively. Thus with valve 9 in the position shown, chamber 17 is pressurized and piston 12 contacts valve member 42 to close its vent passage while opening valve 38 to admit pressure from reser. voir 36 to the auxiliary cylinder 29. Pressure in control line operates relay valve 21 for service braking this pressure being transmitted to both chambers 15, 16 and thus having no effect on valve 8. Loss of pressure in line 27 depressurizes chamber 17 so that piston 12 rises and the auxiliary cylinder is vented; loss of pressure in reservoir 46 also results in auxiliary brake application when service braking is desired since line 24 pressure is transmitted to chamber 16 and is no longer balanced by that in chamber 15. The latter effect also applies if pressure is lost between valve 21 and the service brake cylinder. Manual valve 9 can be depressed to release the auxiliary brake by admitting pressure from reservoir 36 to chamber 17. |
