| 摘要 |
PROBLEM TO BE SOLVED: To provide a pipe end corrosion-proof core for reliably covering an exposed portion of a metal even if the cut end of an inner/outer face coated steel pipe connected via a mechanical pipe joint is not at a right angle. SOLUTION: The pipe end corrosion-proof core 10 comprises an insertion cylinder 12 and a collar 11. An base end side outer diameter d2 of the insertion cylinder 12 is a pipe inner diameter D or larger. The insertion cylinder 12 has a plurality of annular folded portions 13 and annular protruded portions 14, and an annular boss structure 15 located nearest the collar 12. When the corrosion-proof core 10 is pushed into the pipe 1, the annular folded portions 13 are deflected and deformed to cover surfaces of the annular protruded portions 14 and the insertion cylinder 12 is diameter-shrunk at a position of the annular boss structure 15, whereby a region from a base end 12b to the annular boss structure 15 is deformed into a truncated cone shape and the collar 11 is deformed into an umbrella shape. When it is further pushed, the collar 11 has close contact with the end face 1a of the pipe 1. In the mounted state, a force of pressing the peripheral edge 11a of the collar 11 against a pipe end face 1 works at all times, and so the collar 11 has close contact therewith even if the pipe end face 1a is inclined. COPYRIGHT: (C)2009,JPO&INPIT
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