| 摘要 |
PROBLEM TO BE SOLVED: To provide a nut excellent in terms of structivity and fatigue resistance by dispersing stress concentration that occurs in a screw part during screw fastening, and to exhibit a looseness preventive effect by a fastening method similar to a hexagonal nut.SOLUTION: Owing to a structure of 9, 10, 12, 13 enlarged from a screw base line, a bolt can be set freely by hand easily when inserted. When fastened, loads are dispersed and received by each bolt front end part, and the bolt front end part is fastened in such a manner that a wedge is driven in with a nut root inclination angle of 24.5° to 27°, thereby exhibiting the looseness preventive effect. |
