Electromechanical device to move scenery in a theater, uses sensing of movement of control rope to regulate electric motor that provides power assistance to take the place of the counterweight

摘要

The movement of the control rope (14) is decoupled from the pulley (6) carrying the cables supporting the scenery rail (1). When the control rope is in motion, a coding device (24) sends signals to a frequency converter (25) supplying an asynchronous motor (25) with variable frequency. The motor is coupled with a drum which displaces cables (37,38) to operate the cables supporting the scenery.