Non-loosening bolt

A nonloosening bolt which is a locking bolt comprising, in such form as if a single bolt having a threaded portion at an outside circumference thereof had been cut into two perpendicularly with respect to an axis thereof at a location midway along the axis thereof, a first bolt having a bolt head and a second bolt having a threaded tip, the nonloosening bolt being characterized in that

• at the cutting plane of one of the first bolt or the second bolt, an eccentric columnar portion which is smaller in diameter than a diameter of the shaft of the bolt is provided so as to protrude outward in an axial direction in eccentric fashion with respect to a direction perpendicular to the central axis of the bolt, and a small-diameter threaded portion at which male threads are formed is provided at an outside circumference of the eccentric columnar portion;
• at the cutting plane of the other of the first bolt or the second bolt, a small-diameter threaded hole that threadedly engages with the small-diameter threaded portion is formed in eccentric fashion with respect to a direction perpendicular to the central axis of the bolt, female threads being formed at the interior thereof;
• and
• when the small-diameter threaded portion is threadedly engaged with the small-diameter threaded hole such that the cutting planes are made to come in contact in mutually opposed fashion, this results in a constitution in which the central axes and pitches of the threaded portions at the outside circumferences of the first bolt and the second bolt are aligned;
• wherein the eccentric columnar portion is frustoconical in shape and male threads are formed on a side face thereof;
• and
• wherein the small-diameter threaded hole has frustoconically shaped tapered threads at which female threads that threadedly engage with the frustoconical eccentric columnar portion are formed at the inside circumference thereof,
• provided between the cutting plane and the eccentric columnar portion in such fashion as to be eccentric in a perpendicular direction with respect to the central axis of the bolt is a frustoconical protrusion, and provided between the cutting plane and the small-diameter threaded hole in such fashion as to be eccentric in a perpendicular direction with respect to the central axis of the bolt is a frustoconical hole within which the frustoconical protrusion fits.