| 摘要 |
A hand hoist comprises a brake support member (1) for supporting brake plates (24, 25) and firmly mounted on a driving shaft (20) detachably connected through gears to a load pulley (32). A brake biasing member (2) is threadedly engaged on the brake support member by means of a ball screw (43-45), and a retainer ring (3) is fixed to an outer surface of the brake biasing member. A friction transmission ring (5) having a frusto-conical friction outer surface (4) is non-rotatably fitted on the retainer ring, and a manually rotated member (6) for rotating the brake biasing member relative to the brake support member includes a frusto-conical inner surface (7) mating with the frictional outer surface of the transmission ring. Belleville springs (9) urge these frusto-conical surfaces against each other, and they are made of different metals, such as steel, bronze or brass. The retainer ring is provided at its end with a plurality of rotation preventing protrusions (47) circumferentially equally spaced apart, side edges of which abut against pins ( 12,13) planted in holes of the friction transmission ring.
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