| 摘要 |
PROBLEM TO BE SOLVED: To provide a screw capable of preventing looseness by occurrence of returning rotation and easily manufacturable. SOLUTION: This screw 1 is screwed into a mating member 9 while forming a female screw in the mating member 9 for itself. A forward screw part 4 and a backward screw part 5 having an outside diameter almost equal to or larger than that of the screw part 4 are formed on its tip side and in the vicinity of its head part 3, respectively. The screw is suitably used when the mating member 9 is made of a soft material such as plastics or wood, or the mating member made of the soft material like that is overlapped on and jointed to a mating material made of a material not having flexibility such as metal. Since the screw part 4 and the screw part 5 are present on the same axis, it is difficult to rotate it in both forward and backward directions after completion of jointing, so that a detent effect is exerted. The forming positions of the forward and backward screw parts 4 and 5 are separated from each other, the screw is easy to manufacture.
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