| 摘要 |
In brakes in which a friction member is urged into engagement with a rotatable braking member by a fluid-pressure operated actuator, for example internal shoe-drum brakes, the actuator and an adjuster for adjusting brake clearances are located between different pairs of shoe-ends. If the adjuster is automatic, it is difficult to transfer signals at the actuator that adjustment is required to the adjuster with sufficient energy to operate it, without affecting the operation of the actuator. Thus the adjuster is operated by a supply of pressure fluid controlled by a valve assembly which is operative to supply fluid to the adjuster when relative movement between parts of the actuator exceeds a predetermined value. The adjuster is operated by a slave unit. The valve assembly may comprise a valve operated by rotation of a shaft for applying the brake, or two valves embodied in the actuator itself. |
