Through the expansion and collapse cylinder make the wedge shaft for axial reciprocating motion, the piston on the wedge shaft for radial motion, so as to realize the expansion of the segment, and the T-shaped hook on the wedge shaft pulls the expansion and contraction plunger to move inward. The hook on the outside of the expansion and contraction plunger pulls the segment back, thereby realizing the shrinking of the reel. The inside of the reel is designed with a water cooling channel, and the cooling effect is better.