In practice, the possible accidents of the coupling: 

　　1.The axis of the coupling is skewed and the coupling can’t advance: In order to prevent such accidents, in addition to the alignment of the axis, the position of the coupling hole and the shaft, and the position of the striker, it is also necessary to pay attention to the collision. The location of the point should be selected, the first and second hits should be light, and only after a certain interval (about 1/3) of the people enter, can the force be slammed. 

　　2.Other accidents may include: the impact block pulley retreats due to the improper position, the hoist chain slips down, the fuel is insufficient, the fire alarm, etc., all need to be paid attention to in advance and carefully checked during the tool preparation and manipulation practice phase. 

3.When precision parts such as bearings and mechanical seals have been installed on the spindle in advance, it is forbidden to hit and hit the coupling forcefully to prevent damage or damage to the precision parts