| 摘要 |
<p>Spring-applied, pressure-released brakes are useful, for example, in construction vehicles or other vehicles that require an automatic braking in the event of an engine failure. In order to tow the vehicle for service, the brakes must be released. Most brake release systems require an alternate pump and associated valves on each vehicle with the fluid from the alternate pump being controlled by the brake valve on the vehicle. The alternate pump on each vehicle add cost to the vehicle and the spool of the brake valve is a known path for fluid leakage thus requiring an alternate pump of a larger capacity than is actually needed. The present brake release mechanism (10) provides an isolating mechanism (84) that is effective to isolate a work port (46/48) of a brake valve (20) from a valving element (50/52) in a housing (30). The isolating mechanism (84) is adapted to connect with an alternate source (76) of pressurized fluid and adapted to direct the pressurized fluid to a brake (14, 14') for release thereof. The isolating mechanism (84) and the alternate source (76) of pressurized fluid are adaptable to several vehicles thus eliminating the need of the alternate pump and associated valves on each vehicle. Furthermore, the alternate source (76) is smaller in capacity since the leakage in the brake valve (20) during towing is eliminated.</p> |
