How to deal with the twist of the wire rope of the crane hook?

The Crane Hook is a spreader commonly used on overhead cranes and gantry cranes, also known as a hook group. Have you ever encountered such a problem when the crane hook is in use: when you use it, you will find that the wire rope will find the torque, which will cause the hook component to have a tendency to rotate. Yuantai introduces why this happens and how to deal with it?

No matter what type cranes, specification, or grade of wire rope used by cranes, torque will be generated when subjected to force. Torque is caused by the way the wire rope is made, first the wires are twisted together helically to form strands, and then several strands are twisted together again to form the rope. When the force is applied, the wire and the strand will be straightened, but the end of the wire rope is fixed during the hoisting operation, so that a torque is formed in the wire rope. Another source of torque is that the pitch of the wire rope becomes longer after a period of use, so that when the end is fixed, the wire rope generates torque without being stressed. The existence of torque makes the hook assembly tend to rotate. .

On the other hand, there are many external factors that directly cause the hook to rotate. For example, external forces such as manpower or wind force during the hoisting process push the hook to rotate. The crane driver’s operation is unstable, so that the hook and heavy objects swing, causing the hook to rotate. The method causes the hook to be unbalanced, causing the hook to rotate, etc.

The rotation of the crane hook often occurs without any warning in the equipment hoisting operation. When the crane lifts the heavy object, the hook rotates, and the wire ropes wrapped around the hook pulley block are twisted together, and the lifted heavy object is twisted together. It also rotates with the hook. At this time, it is no longer possible to continue to lift and lower the heavy objects that have been lifted. The rotation of the hook will affect the normal operation of the crane hoisting and seriously threaten the safety of operators and equipment, so it must be avoided.

The specific treatment method for the torsion of the crane hook:

(1) When the heavy objects are not high off the ground and the crane performance allows, the heavy objects can be lowered slowly, and then the hook can be screwed up.

(2) If the heavy object has been lifted high off the ground, you can only find a way to close the hook of the crane manually.

(3) After the hook rotation occurs, the torque in the wire rope should be released. The specific method is: put the hook on the ground, untie the fixed end of the wire rope, multiply the number of turns m of the hook rotation by the matching of the wire rope The number n is the base number k (it can be increased or decreased depending on the actual situation). According to the reverse direction of the wire rope twist, turn the end of the wire rope to release the torque, and then install the fixed end. Repeat the above steps by repeating the lifting and lowering hook a few times to check the effect.