Method of expanding diameter of existing pipe by non-excavation method and expanding tool used for it

摘要

PROBLEM TO BE SOLVED: To provide a method for enlarging diameter of an existing pipe by non-opening/scraping method and a tool used for it.SOLUTION: Used is an enlarging/opening tool consisting of: a supporting axis part which is arranged at center and comprises screw at periphery; an elevating arm which extends in a crossing manner with the supporting axis part, and being screwed on the supporting axis part at center to elevate along with the supporting axis part; a work arm which is engaged on the elevating arm in a pivotable manner and comprises prongs hooked on opposing edge parts along with a crack on tip of the existing pipe Tip of the supporting axis part is brought into contact with outer wall corresponding to a crooked part resulting from enlarging diameter with a cutting/enlarging diameter tool. The prongs are hooked on a pair of edge parts of the existing pipe. tip of the supporting axis part of the existing pipe is relatively displaced to outside in tube diameter direction as by rotating the supporting axis part to enlarging the crack.