WELDED STRUCTURE OF POCKET OF FILE AND METHOD FOR WELDING

摘要

PROBLEM TO BE SOLVED: To provide a file prepared by using a sheet made of foamed resin as a cover and by welding a pocket sheet with ultrasonic waves to the inner side thereof. SOLUTION: A bag-shaped pocket sheet 17 of which one end is opened is laid over the inner side of a file main body 11 and the intermediate part of this pocket sheet 17 and the inside of a backbone 14 are connected to each other through the intermediary of a welded part 20. The welded part 20 is provided intermittently and also provided in the shape of a sink so that a recessed part 21 having an annular outer edge be formed. The inner peripheral edge of the recessed part 20 and an edge part 17A of the pocket sheet 17 corresponding thereto are welded to each other, while a fusion lump of the file main body 11 and the pocket sheet 17 is formed in the bottom of the recessed part 20 continuing to the edge part 17A.