| 摘要 |
<p>Provided is a bolt capable of being tightened without using a special tool, incapable of being loosened after being tightened, but capable of being loosened in an emergency situation, and also provided is a tool. A bolt is configured, including: a fastening bolt having a through-hole formed at the shaft center, a serration surface formed at the upper surface of the head portion, and a tool engaging recess portion drilled at the center; a sliding shaft slidably inserted into the through-hole; a top rotational driving body fastened to the upper end portion of the sliding shaft and having a second serration surface that is formed on the lower surface and is to be engaged with the serration surface in a coaxial fashion; and a locking body attached to the lower end portion of the sliding shaft and restricting the movement of the shaft of a tightening bolt. The top rotational driving body has a step portion formed by reducing the diameter or a trench portion, which is formed on the side circumferential surface thereof, a tool engaging portion formed on the upper surface or on the side surface, and a recess portion formed on the upper surface and exposing the upper end surface of the sliding shaft.</p> |
