| 摘要 |
PROBLEM TO BE SOLVED: To restrain deterioration in close contactness of a corrosion preventing core. SOLUTION: A fixed ring 8 is provided over the whole circumference of the inner surface of cylindrical part inserted into an inner surface of a pipe end of a pipe end corrosion preventive core 7, and the core 7 is fixed to the pipe end with the cylindrical part which makes pressure welded with the inner surface of tube end by the ring 8. The ring 8 is cut at one portion in the circumferential direction, so as to be openable while both ends 8a, 8b thereof are fastened by blind rivets 20 by use of a connection piece 10. Holes 14, 11 of the piece 10 and the end 8a are provided at several pitches, respectively, while the former has a pitch shorter than that of the latter. This relates to between the main part and sub part of calipers, and when the ring 8 is widened in its diameter, the axes of the holes 11, 14 vary, and then with the holes 11, 14 whose axes are made identical both the ends 8a, 8b are widened with the rivets 20. Accordingly, tolerance for the inner diameter of pipe can be absorbed and effective pressure contact of the core 7 can be maintained for a long period of time by the ring 8.
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