| 摘要 |
PROBLEM TO BE SOLVED: To sharply improve load bearing performance by refining the shape of a fastener by using an existing fastener as much as possible without changing the thickness of the fastener.SOLUTION: A first contact part 17 as a connection part between a first horizontal side part 14 and a second horizontal side part 15 can come into contact with the internal surface of a first vertical side part 12, and a second contact part 18 disposed between a connection part between the second horizontal side part 15 and a third horizontal side part 16 and the third horizontal side part 16 can come into contact with the internal surface of the second vertical side part 13. A slip surface having an arc-shaped cross section is arranged diagonally downwards from the internal surface of the second vertical side part 13 at a lower position than a position where the second contact part 18 comes into contact with the internal surface of the second vertical side part 13 such that the second contact part 18 slips in contact with the slip surface. |
