PLUG DIRECTION CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To provide a plug direction control method, wherein the direction of a plug will not be twisted or the inner peripheral surface of a coupon will not be deviated from the inner peripheral surface of a main pipe. SOLUTION: A pair of pin insertion holes 14 are formed in a flange-form part 11, in which a recess groove 12 is formed and a plug 20 is provided at an outer end part with a stopper 23. The stopper 23 is brought into contact with one of stop pins 15 inserted in one pin insertion hole 14 and rotation of the plug 20 is stopped. The other stopper pin 15 is inserted in the other pin insertion hole 14 to block turning the plug 20 in the opposite direction.