| 摘要 |
<p>PRESSURE HOLDING VALVE A pneumatic vehicle spring parking brake pressure holding valve abruptly seals an atmospheric outlet and enables the valving of brake release air pressure to the spring parking brakes when the vehicle reservoir attains a first pressure. Parking brake release is thus enabled. In the case of loss of air pressure from the system, the pressure holding valve retains the brakes fully released until the vehicle reservoir air pressure drops to a second pressure which is lower than the first. The pressure holding valve thereupon abruptly opens its atmospheric outlet thereby rapidly exhausting the air pressure in the spring parking brakes and setting them.</p> |
