| 摘要 |
<p>The automatic safety device works with a rope passing through it to arrest a load in the event of breakdown of a motor-driven or manual hoist or winch. An automatic rope grip mechanism has two jaws (13, 13') near the rope and thrust towards it by a pair of spring-loaded levers (14, 14') pivoting on flanges (12, 12') parallel to the rope, and joined to it via the housing of the mechanism. When the jaw assembly is not prevented from gripping the cable a switch connected to the mechanism cuts off the supply to the motors. As long as the relative speed of rope and grip mechanism is below a predetermined value, a locking device prevents the mechanism operating. An automatic release mechanism is actuated by the centrifugal force in a weight (32) rotated by a pulley (41) in turn driven by the rope when the speed of the latter exceeds the value referred to, rendering the locking device inoperative. This can also be done by a hand centre, independent of rope speed.</p> |
