Traction elevators with adjustable traction sheave loading, with or without counterweights

摘要

Elevators operating in hoistways serving landings at different floor levels of multi-story buildings are each provided with a compensation or comp sheave engaged in the lower bight of the rope, at the lower end of the elevator hoistway, with all or most of the weight of the comp sheave and its bearings and support assembly being carried by the lower rope bight, providing traction and transmitting tension force to the rope. The comp sheave assembly may include a motor drive machine and brake, providing traction drive at the lower hoistway end, and the consequent tension control can replace the elevator's conventional counterweight. An adjustable comp sheave support assembly achieves tension adjustment in the rope, reducing rope tension when desired, and readily adjusting rope tension for quick releveling of the elevator to compensate for loading changes as they occur.