| 摘要 |
<p>A double check (70) valve is integrally located in a spring brake chamber to reduce plumbing associated with a pneumatic brake system. Anti-compounding is provided by virtue of a bias pressure of approximately twenty to thirty psi between a pressure chamber (52) of a service actuator (44) and an operating chamber (66) of a parking/emergency actuator (46). Likewise, vehicle roll-back is addressed since the transition from a service application to a park application assures that the service brakes are sufficiently applied until the spring brake becomes operative.</p> |
