| 摘要 |
A chain hoist for supporting and selectively raising and lowering a load includes a powered gearwheel that is connected through a frictional lock with one or more friction disks fixed for rotation with the hoist drive shaft so as to provide a slip clutch arrangement. The hoist additionally includes, between one of the friction disks and a pressure spring, a safety brake disk for rapidly halting movement of the load in the event that the rotation of the brake disk attains or exceeds a predetermined speed or rate deemed to be excessive. For this purpose, the brake disk carries a detent pawl that is pivotally displaced by centrifugal force and into engagement with a detent nose or projection defined on the hoist housing when the brake disk rotation exceeds the predetermined speed.
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