Rotate the hook phenomenon

   Rotate the hook often occur without any warning lifting operations in the device, when the crane lifting weights,rope hoist the hook spin up, worn around the hook and boom top pulley rope twisted tangled between being the heavy lifting is also rotated together with the hook up, then have been unable to continue lifting or lowering a weight lifted. Rotate the hook lifting operations will affect the normal conduct of a serious threat to the safety of operating personnel and equipment, it is necessary to avoid its occurrence.
       Rotate the hook with the following factors:
       (1) The more large cranes, lifting height of its higher, that boom among the top rope pulley block and hook longer the greater the possibility of rotating hook;
       (2) into a single hook wire rope reeved match the number of matches than double the number of rotating hook is easy to make and wear around the steel wire rope of a small number of matches,wire rope winch the greater the possibility of rotating the hook;
       (3) exposure to a single rope greater the weight, the greater the possibility of rotating the hook;
       (4) The dimensions of the hook component and smaller the size of the pulley, the greater the possibility of rotating the hook;
       (5) Operation crane hook landing speed is not stable, especially when heavy loads from the ground,manual hoist increasing the likelihood of the hook rotation.