Enlarged diameter for a cutting tool of the existing pipeline

摘要

PROBLEM TO BE SOLVED: To provide a cutting tool for enlarging a diameter of an existing pipe line which does not require a working space and a worker at the back side of the existing pipe line while enabling to collect a cutting blade under any circumstances, shorten an extension rod in the long existing pipe, and bringing a support shaft back to the opposite side in the case of a trouble.;SOLUTION: A plurality of the cutting blades 5 are housed slidably in the radial direction in a storage part 4 of a seat member 2 which is prevented from rotating and slidably fitted around the support shaft 1. The cutting blades 5 are biased by an extension coil spring 8 toward the inside of the radial direction, so that an abutting member 6 provided at the base side of the cutting blade 5 abuts on a tapered part 9a formed on the outer diameter surface of a diameter enlarging member 1b of the support shaft 1. When the support shaft 1 is moved in one direction in the cutting operation, the seat member 2 is slid toward the large diameter side of the tapered part 9a making the abutting member 6 engaged with the large diameter side of the tapered part 9a, thereby pushing the cutting blade 5 toward the outside of the radial direction. When the support shaft 1 is moved in the opposite direction, the seat member 2 is slid toward the small diameter side of the tapered part 9a, thereby storing the cutting blade 5.;COPYRIGHT: (C)2011,JPO&INPIT