| 摘要 |
A park brake valve arrangement for a trailer of a commercial vehicle having a main air supply line 1 which supplies a manually operable shunt valve 12 connected to a first and second two-way valves 13, 14. The first two-way valve is connected to a park valve 15 and an exhaust 3. The second two-way valve also receives an input from a trailer based reservoir, which input is also connected with an output of the shunt valve 12 and the inlet of the first two-way valve 13. The outlet of the second two-way valve is connected to an electrically biased two way valve 16 adapted to control the park valve 15 which park valve 15 is connected to the spring brakes 2 of the trailer and the exhaust 3. When the arrangement is in the Drive position (fig 2), the main line is pressurized and there is an electrical connection from the tractor to the EBS, the shunt valve 12 is connected to both two-way valves 13, 14. The outlet of the first two way valve 13 is connected to the park valve 15, which supplies pressure to the spring brakes 2. The spring brakes are biased into the on position so that the spring brakes are held in the off position when pressurised. |
