| 摘要 |
PROBLEM TO BE SOLVED: To bore a hole in the diametrical direction of a pipe, even if a space for boring work does not sufficiently exist on the pipe side, in a method for boring the hole in the gas pipe by a hole saw installed in a hole saw insertion port, after installing a thermoplastic resin branch pipe having a saddle part, a vertical body part projected from the saddle part, the hole saw insertion port and a branch pipe connecting port arranged in the vertical body part, in a polyethylene gas pipe by the saddle part. SOLUTION: The hole saw 16 is installed in an expansion body 17 expanding in a telescopic shape, and is inserted in parallel to the gas pipe 1 from the hole saw insertion port 14 attached with a tool 24 having a shutter device 23. A hydraulic fluid is supplied in the expansion body 17 after reaching the vertical body part 13. The hole saw 16 is projected in the diametrical direction of the gas pipe 1 by extending the expansion body 17, and the hole is bored by push-cutting. After boring the hole, the expansion body 17 is contracted by discharging the hydraulic fluid from the inside of the expansion body, and the hole saw 16 is returned, and then, is removed via the shutter device 23 by the hole saw insertion port 14. COPYRIGHT: (C)2009,JPO&INPIT
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