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MATERIALS HANDLING AND STORAGE |
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Overhead and Gantry Cranes - Hoisting Equipment |
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Sheaves are grooved pulleys which carry the hoisting ropes on overhead
cranes. Sheave grooves must be smooth and free from surface defects. Sheaves in the bottom blocks shall be equipped with close-fitting guards to prevent ropes from becoming fouled when a block is lying on the ground with the rope loose or when there is a slack cable condition. Guards prevent the hoisting rope from coming off the sheave groove and becoming entangled on the shaft, creating binding or shaving of the hoisting rope. It is required that the hoisting ropes have no less than two wraps remaining on the hoist drum when the hook is in its extreme low position. |
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