In mill plants, the gear and rack are usually adopted as the pushing system of the three magnetism blocks of the pushing bed in magnetic force, The three magnetism blocks are out of step to start in the first twinkling of an eye in operation,that means driving single magnetism block instantaneously, It makes this magnetism block instantly overloaded, which will cause the rack to slip the tooth.

Synchronous control effects of push and draw bench can be obtained in the front and back of the blooming mill if fine turning technology is applied to blooming mill push and draw bench of the metallurgical intrument based on differential gear principle.