| 摘要 |
PROBLEM TO BE SOLVED: To bulge a circumferential projection at an arbitrary requiring part on the outer circumferential face of a metal tube. SOLUTION: This method is composed of the process where 1st dies 11 (11a, 11b) and 2nd dies 13 (13a, 13b) corresponding to the shape of circumferential face of a metal tube 1 are closely attached or brought into close contact with the total circumferential face of the metal tube 1 so as to insert the requiring part, and the process where an end edge or both end edges of the metal tube 1 are pressed in the longitudinal direction, and in the the process of pressing the metal tube, the dies 13 positioned on the pressing side are moved to the pressing direction in the state of closely attaching on the circumferential face of the metal tube 1 or being brought into close contact with the above, and the circumferential face positioned between the 1st dies 11 and the 2nd dies 13 is bulged with projecting.
|
