Patent ID: 7866930
Filing Date: 2011-01-11
Classification: F16B

Abstract:
1. A bolt having a head portion and a shaft portion extending therefrom on which a helical thread is formed, the bolt being adapted to be tightened into a single direction receiving female screw member such as a nut, wherein the shaft portion is comprised of a constant diameter thread portion having a constant diameter formed on the proximal end side that extends over a predetermined length and subsequently the diameter is decreased from the distal end of the constant diameter towards the front, so the external screw thread shape thus formed is tapered at an angle down to a reduced forward diameter, and a guide thread portion is formed on a front end side thereof and having a smaller diameter than the constant diameter thread portion, wherein a thread formed on the guide thread portion is formed in an inverted screw direction with respect to the helical thread formed on the constant diameter thread portion, and wherein the thread formed on the guide thread portion is formed into a double threaded screw configuration in the inverted screw direction.