Hook rotation phenomenon
The hook rotation is often without any warning in the equipment hoisting operation, when the lifting crane lifts the heavy weight, the hook rotates, and the wire rope twisted around the hook and the top pulley of the jib is wrapped together, and the lifted weight is rotated together with the hook, which can no longer lift or put down the lifted weight. Hook rotation will affect the normal operation of hoisting operations, serious threat to the safety of workers and equipment, it must be avoided.
The causes of the hook rotation are internal and external factors, and the internal cause of the hook rotation is also the root cause of its occurrence.
The wire rope used by the crane, regardless of the type, specification and brand, will produce torque in the force. The torque is caused by the way the wire rope is made, first the wire spirals together to form the strands, and then the strands spiral together to form a wire rope. When the force, the wire and the stock will be straightened, but the lifting of the wire rope end is fixed, so that the wire rope formed a torque. Another source of the torque is the length of the steel rope after a period of use, so that it is fixed at the end of the case, the wire rope is not force will produce torque, the existence of torque to the hook Assembly has a rotating trend.
On the other hand, there are many external factors directly lead to the hook rotation, such as the hoisting process of manpower or wind force to promote the hook rotation, the driver is unstable so that the hook and the weight swing led to the hook rotation, the hook through the way the hook is uneven lead to hook rotation and so on.