Importance

Loading Importance Indicators...

Abstract

The safety system in a hoist having a motor with a motor shaft, a gear reduction unit, 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 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 and is easily reset remotely after the brake has been set.

Loading the Abstract Image...

First Claim