The hook rotation often occurs during the equipment hoisting operation without any warning. When the hoisting machinery lifts the heavy object, the hook rotates, and the wire rope passing through the hook and the pulley block on the top of the boom is twisted and twisted together. The hoisted heavy object also rotates with the hook, and at this time it is no longer possible to continue to hoist or put down the already hoisted heavy object. The rotation of the hook will affect the normal operation of the hoisting operation and seriously threaten the safety of the operators and equipment, so it must be avoided.
The crane hook rotation is related to the following factors:
(1) The larger the crane, the higher the lifting height, that is, the longer the wire rope between the top pulley block of the boom and the hook, the greater the possibility of the hook rotating;
(2) The singular matching of the hook wire rope is easier to make the hook rotate than the even number matching, and the number of matching wire ropes is less, the greater the possibility of the hook rotating;
(3) The greater the weight of a single wire rope, the greater the possibility of the hook rotating;
(4) The smaller the size of the hook assembly and the size of its pulley, the greater the possibility of the hook rotating;
(5) The speed of operating the crane hook is not stable, especially when the heavy object is off the ground, the possibility of the hook rotating increases.
