摘要 |
In order to provide a lock nut having a high reliability free from loosening, three nuts are used. The nut closest to the bolt head and the intermediate nut are engaged with each other in only the peripheral direction and do not come into surface-contact with each other in the axial direction, thereby aligning the outer peripheries thereof and forming internal threads on a variety of center bores. Then, the intermediate nut and the outermost nut are brought into press-contact with each other in the axial direction.
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