MECHANISM FOR DETECTING OVERSPEED IN LIFTING APPARATUSES, OVERSPEED PREVENTION SAFETY ACTUATION DEVICE AND LIFTING APPARATUS

摘要

The invention relates to a detector mechanism which can be mounted to a pulley (50, 50') or to the car of a lift (3). The invention comprises a wheel (13) which rotates according to the speed of the car (3) and pivot arms (20, 21) which tilt under centrifugal force as the wheel (13) rotates. The invention also comprises magnetic means which are associated with the pivot arms (20, 21) and which generate an attractive force which maintains the position of the pivot arms (20, 21) until the centrifugal force exceeds the attraction of the magnetic means. The invention further comprises an end stop element (30) which forms part a piece (11-11') that is external to the wheel (13) and against which the pivot arm (20, 21) comes into contact when the centrifugal force generated on the arm (20, 21), as a result of the overspeed of the lift car (3), exceeds the attractive force of the magnetic means, thereby initiating the braking of the car (3).