| 摘要 |
PROBLEM TO BE SOLVED: To provide a metal pipe for a hole saw which is lightweight and of sufficient strength and capable of easily securing a water channel. SOLUTION: The metal pipe 10 for the hole saw is structured of a cylindrical outer pipe 12, a cylindrical inner pipe 14 with a smaller outside diameter than the inside diameter of the outer pipe 12, a welded part 32 having an equal outside diameter to the outside diameter of the outer pipe 12 and an equal inside diameter 14 to the inside diameter of the inner pipe 14 and an inserting/fitting part 34 having an outside diameter almost equal to the inside diameter of the outer pipe 12 and an inside diameter almost equal to the outside diameter of the the inner pipe 14. In addition, a joining ring 18 with a through hole 36 running through the welded part 32 and the inserting/fitting part 34, is provided as a constituent component. The inner pipe 14 is interposed in the outer pipe 12 and the inserting/fitting part 34 of the joining ring 18 is fittingly interposed in the gap between the outer pipe 12 and the inner pipe 14. The aperture rims of the outer pipe 12 and the inner pipe 14 are fixedly welded with the welded part 32 in one piece. COPYRIGHT: (C)2004,JPO
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