| 摘要 |
<p>An anti cross-thread bolt which prevents the bolt from being cross-threaded without the need for correcting its posture by a pilot portion. The bolt is screwed into a female screw having a nominal diameter D and an inner diameter D1. At the tip of a regular thread part formed on the bolt shank, a small-diameter thread part is formed by one pitch or more, the small-diameter thread part having an outer diameter d which is larger than an inner diameter D of the female screw and smaller than (D+D1)/2. When the bolt is obliquely screwed into the female screw, the small-diameter thread part is brought into contact with the female screw at one point, but the bolt is allowed to rotate around the point. Thus, the occurrence of cross-threading is prevented.</p> |
