| 摘要 |
<p>Provided is a locking double nut comprising a lower nut (1), an upper nut (2) and a cover (3) for covering the outer circumference of the lower nut. The upper nut (2) includes a circular cylinder portion (7) having a smooth outer circumference, and a turning operation portion (8) molded integrally with the upper end of the cylinder portion (7) through a connecting portion (9). This connecting portion (9) is so formed as is broken, when the upper nut is fastened with a turning tool by a fastening torque exceeding a predetermined torque, so that the turning operation portion leaves the cylinder portion. The cover (3) has a cylindrical body portion (13) for covering the outer circumference of the lower nut. The cylindrical body portion (13) has a smooth outer circumference (16), and its upper end portion contacts the lower face of the upper nut 2, when the upper nut 2 is fastened, so that the cover (3) cannot be removed. As a result, both the upper and lower nuts cannot be turned after fastened.</p> |
