摘要 |
The present invention utilizes a hoist drum with a number of different diameter sections upon which the different ends of a lifting cable simultaneously spool on and off of as a function of counterclockwise and clockwise cable spooling. This combination reduces the amount of shaft torque required to raise or lower a load while increasing the number of hoist drum rotations required to raise or lower that load. These two features are incorporated into the operation of a main crane cable length adjusting device since they offer precise and rapid adjustment capabilities to be made with smaller sized electric motors and clutches.
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