Safety braking system for electric lift cabin - includes centrifugal brake linked to cable drum and controlled by cabin position sensors to control rate of descent

摘要

The lift includes a carriage with a motor driven cable drum attached to its roof, and a further drum at the top of the lift shaft. An electromechanical control system links the operation of these two motors to the control panel within the lift cabhin, and detectors sensing the position of the cabin. A centrifugal brake is linked to the cable drum on the cabin roof by a gear train. When the power fails the cabin is initially locked in the partic. position, but subsequently is allowed to descend under the force of its own weight. The centrifugal brake mechanism controls the rate of descent. Although the power supply is represented as two input lines, it may in practice be a three-phase supply with earth connections.