Lift safety mechanism

摘要

A safety mechanism for a lift system, the safety mechanism including a first motion retarder which operates frictionally between a load-carrying platform and a hoistway and a second motion retarder which operates by breaking a frangible element. The two motion retarders may act together so that when the frictionally engaging element is depleted, the frangible elements are then broken. In an embodiment, the frictional element is disengaged to engage the breaking of the frangible elements when the car is a predetermined distance above a floor of the hoistway, thereby ensuring that the load-carrying platform can be stopped prior to a collision with the floor or ceiling of the hoistway.

主权项

1. A safety mechanism for a lift, the lift comprising a load carrying platform arranged for movement relative to a hoistway, the safety mechanism comprising first and second motion retarders acting between the load-carrying platform and the hoistway for reducing a speed of the load-carrying platform relative to the hoistway wherein the first motion retarder includes a friction brake and the second motion retarder includes a tearable element, wherein
the first motion retarder includes a brake pad which engages frictionally with the hoistway to retard the speed of the load-carrying platform, the frictional engagement of the brake pad with the hoistway causes wear of the brake pad, and the second motion retarder is mounted relative to the first motion retarder so that the second motion retarder engages in response to wear of the brake pad below a threshold brake pad level.