| 摘要 |
PROBLEM TO BE SOLVED: To downsize an insertion part and also to maintain strength of the insertion part.SOLUTION: An insertion part 11 comprises: a wound part 11a; and a core material part 11c having a thin-strip shape and connected to the wound part 11a through a connecting piece 11b. The core material part 11c is rolled inside the wound part 11a by folding the same, and includes a widened part 11k at the tip end part thereof and a projection piece 11l formed in a part of the widened part. In the insertion part 11, the connecting piece 11b is folded to arrange the core material part 11c above a lower surface part 11e of the wound part 11a, and the projection piece 11l is fitted to a hole part 11j of the lower surface part 11e to position the core material part 11c and also to avoid the core material part 11c from positional shifting with respect to the wound part 11a. Simultaneously, the connecting piece 11b is cut off from the core material part 11c at an A part, and is cut off from a projection part 11i at a B part. Then, side surface parts 11f and 11g are raised and further, an upper surface part 11d is folded to roll in the core material part 11c. |
