Hoist and traction machine with free rotation control

摘要

A hoist and traction machine having a free rotation control device/apparatus for selectively controlling the mechanical brake to be inoperative and for maintaining the inoperative mode of the mechanical brake, so as to control the free rotation of the load sheave. The free rotation control device is designed such that improved free rotation control operation can be provided, and the range of the pulling force for the chain can be enlarged in the controlled free rotation of the load sheave; thus, allowing the chain to be pulled quicker, while requiring little operating skill. Further, free rotation operation is not provided when the load sheave (and thus the driving shaft) is subjected to a large load acting in the direction of hoisting down the load, thus achieving highly improved safety.