RIGHT/LEFT HANDED SCREW, MANUFACTURE THEREOF, AND NUT LOCKING DEVICE USING RIGHT/LEFT HANDED SCREW

摘要

PROBLEM TO BE SOLVED: To form both a right-hand thread and a left-hand thread in such a shape as to allow nut to be thread-fastened thereto by forming one of the right-hand thread and left-hand thread on the peripheral surface of a shank material so that the ridge part of the thread is smaller than normal thread shape, and forming the other of the right-hand thread and left-hand thread at the ridge part of the thread. ;SOLUTION: This right and left handed screw A is formed by providing a right-hand thread 2 and a left-hand thread 3 in an overlapped manner in the same position of a circular shank 1 of a bolt or the like. The right-hand thread 2 and left-hand thread 3 are separately formed by rolling using a pair of dies. The right-hand thread 2 formed in the first half by rolling is formed in normal thread shape from a root part 4 of a thread ridge to a pitch line P, and linear flanks 5 are provided on both sides to secure fastening strength to a thread-fastened nut. The portion of a ridge part 6 from the pitch line P is formed to be smaller than the normal thread shape. The left-hand thread 3 is formed by rolling a root part 9 at the portion of the ridge part 6.;COPYRIGHT: (C)2001,JPO