To easily and surely fasten a nut with proper fastening torque, and to prevent the nut from being easily taken out by mischief or the like after fastening.
This nut comprises a nut body 7 having a screw hole 5 at a shaft center in a state of being axially penetrated, a rotating tool engagement portion 8 mounted at the axial upper portion of the nut body 7, and a connecting portion 9 for connecting the nut body 7 and the rotating tool engagement portion 8, and is integrally molded, a cavity 11 having a diameter larger than the diameter of the screw hole 5 is formed at the shaft center of the rotating tool engagement portion 8, and the connecting portion 9 is broken when the rotating tool engagement portion 8 is fastened by fastening torque exceeding prescribed torque by a rotating tool engaged with the rotating tool engagement portion 8, thus the rotating tool engagement portion 8 is separated from the nut body 7.
JPH07310725 | SCREW FALLING PREVENTION STRUCTURE |
JP6260843 | A lock nut not loosening |
JP2000035027 | BOLT, NUT, AND FASTENING JIG |
JP2003254312A | 2003-09-10 | |||
JPH11303839A | 1999-11-02 | |||
JP3000526B |
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