| 摘要 |
<p>SAFETY MECHANISM FOR HOISTING DRUMS The safety system in a hoist having a motor with a motor shaft, a power transmission main drive, a drum, a safety brake drivingly coupled on an operating element on or close to the drum in which a mechanical out-of-sync detector produces a bidirectional or, preferably, a unidirectional brake-setting output from inputs from the drum and the motor shaft,the unidirectional brake-setting rotational output for setting the brake. In a preferred embodiment, an error correction is made into the detector for obtaining a first unidirectional output during normal operation, and the brake-setting unidirectional rotation is in the opposite direction for setting the brake. One form of detector is a mechanical differential assembly and another form of detector is a set of coaxial shafts that measure differential rotation between the drum and motor input shafts. A unique brake actuator is provided which uses a large spring force which is controlled by a trigger mechanism and is easily reset remotely after the brake has been set.</p> |
