| 摘要 |
PROBLEM TO BE SOLVED: To provide a bolt or nut (especially, a hexagon bolt or hexagon nut) for preventing malicious detachment. SOLUTION: In this hexagon bolt or hexagon nut fastened or loosened by a fastening tool such as a box wrench, a first notch and a second notch are arranged on each side of the head part of the hexagon bolt or nut, thereby allowing only compressive stress to act on a protruded part between the first notch and the second notch when the bolt or nut is fastened by the fastening tool such as the box wrench, and tensile stress by bending to act on the protruded part so as to act on the second notch when it is loosened by the fastening tool. Thus, the head part of the bolt or nut is broken from the second notch. COPYRIGHT: (C)2011,JPO&INPIT
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