| 摘要 |
<p>A pair of tandem master cylinders (1, 2) have primary pressure spaces (18) connected to the brakes on one pair of wheels on opposite sides of the vehicle, and an actuator (60) forthe brakes on a trailer is supplied with fluid under pressure from pipe-lines connected to each ofthe four pressure spaces (18, 20) and under the control of first and second disabler valves (61, 62). Each disabler valve (61, 62) has a pair of inlet ports (71, 72), each connected either to respective primary pressure spaces or respective secondary pressure spaces, and an outlet port (73) connected to the actuator (60). When one master cylinder is operated on its own both disabler valves are closed to prevent the actuator (60) from being operated. Failure of one pressure space, when both master cylinders are operated simultaneously, causes the corresponding disabler valve to close but the actuator (60) can still be operated from the operative pressure spaces, through the other disabler valve.</p> |
