Reasons and Solutions for Hook Rotation
Hook rotation often occurs without any indication. When the crane is lifting a heavy object, if the hook rotates, the steel wire rope wound between the hook. The boom pulley group will twist together, and the lifted object will also rotate with the hook. At this point, the crane cannot continue operating.
The rotation of the hook can affect the construction progress. In severe cases, it can even threaten the safety of construction personnel and equipment, so it is necessary to avoid its occurrence. How should this situation be resolved?
Reasons for hook rotation
The larger the crane, the higher its lifting height. That is, the longer the steel wire rope between the boom top pulley block and the hook, the greater the possibility of the hook rotating;
It is easier for the hook to rotate when the wire rope of the hook is wound in an odd number than in an even number. And the fewer wire rope matches are wound, the greater the likelihood of the hook rotating;
The greater the weight borne by a single steel wire rope, the greater the likelihood of the hook rotating;
The smaller the shape and size of the hook component and its pulley, the greater the possibility of the hook rotating;
The speed of operating the lifting hook of the crane is unstable, especially when the heavy object is off the ground, the possibility of the hook rotating will increase.
Measures for handling hook rotation
When the heavy object is not high off the ground, it can be lowered by using the method of amplitude variation. And then the hook can be rotated to the right position.
If the heavy object has been lifted very high from the ground. Then we can only find a way to get close to nearby buildings to straighten the hook.
After the hook rotates, release the torque inside the wire rope.
The detailed method is to place the hook on the ground, loosen the fixed end of the steel wire rope. And multiply the number of turns m of the hook by the matching number n of the steel wire rope as the base k (which can be increased or decreased according to the actual situation). Roll the end of the steel wire rope in the opposite direction of the twisting direction, release the torque. And then install the fixed end. Raise the lifting arm to the maximum elevation angle and repeat lifting and lowering the hook several times to check the effect. The above steps can be repeated until the hook is not disordered.
