| 摘要 |
PROBLEM TO BE SOLVED: To provide a nut capable of ensuring a tightening with a torque of a predetermined value or more in addition to a loosening-stop function and carrying out a recognition of the state from a remote place. SOLUTION: A washer part 20 is continuously provided at one edge surface 12 side of a nut body 10 having the similar shape to a usual nut through a thin cylindrical connection portion 30 broken by a twisting torque of a predetermined value or more. A coloring agent 40 is filled in a space X between opposed edge surfaces 12, 22 of the nut body 10 and the washer part 20. When the connection portion 30 is broken and the nut body 10 and the washer part 20 are press- fitted, the coloring agent 40 is pushed out from the space X to color a periphery of the nut body 10.
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