| 摘要 |
A two-way check valve is utilized with each brake assembly to apply pressure against a single actuating diaphragm. One inlet port is connected to the service air supply and one inlet port is connected to the emergency air supply. Satisfactory pressure of either supply operates the brake connected to the brake assembly in a service manner, the loss of air pressure in either supply causing that supply to be closed by the check valve. Emergency air venting from a spring-biased piston with a pawl end causes the pawl to engage a rack surface of the brake actuator rod. Hence, no spring is used to power the brake actuator rod and brake connected thereto closed when there is a loss service air pressure.
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