| 摘要 |
PROBLEM TO BE SOLVED: To inexpensively obtain a screw component exerting a certain locking effect with a simple structure. SOLUTION: In the screw component 1 comprised of a head portion 2 and a leg portion 4 formed of a screw thread 3, a projection 11 projecting in a pyramid-shape is arranged on a seat surface in the circumferential direction at a plurality of equal intervals. Since a ridged line 12 of the projection 11 is a locking screw component turning to a screw-fastening rotative direction, when the locking screw component is fastened to a work applied with corrosion preventive treatment by means of a special organic film for making influence to an environment reduced in recent years, a frictional coefficient is increased right before seating of the screw component, and the projection is cut into the work by canceling slippage and by surely breaking the surface of the work. Further, the destruction of a female screw is hardly produced so that a axial force generated when completing fastening of the screw is not suddenly increased from a preset value. Furthermore, cutting-into the work by the projection is facilitated so that the ridged line of the projection existed in the screw- fastening rotative direction.
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