Double-end threaded body and internally-threaded body

摘要

A duplex threaded body having a right-handed and left-handed thread on the circumferential surface of a single solid member. A single-nut or double-nut type internally-threaded body demonstrates a locking effect at an intermediate position without substantially loosening by using a combination of a duplex externally-threaded body and one or more internally-threaded bodies. Moreover, a screw structure in which a pair of internally-threaded bodies can only be removed once they are mutually coupled when screwed onto a duplex externally-threaded body, making it possible to impart tamper-proof characteristics and a locking effect. The duplex externally-threaded body has, on the outer circumferential surface, an overlapping region with a clockwise spiral right-handed thread and a counter-clockwise spiral left-handed thread in an overlapping manner. A right-handed internally-threaded body in which a right-handed thread is formed, and a left-handed internally-threaded body in which a left-handed thread is formed, that are screwed onto a duplex externally-threaded body.