| 摘要 |
<p>A loosening preventive fastener for a screw tool formed in a relatively simple structure, easily manufacturable at low cost by mass production, and capable of easily and securely preventing a screw tool from being loosened as a fastener for a screw tool miniaturized or refined by precise processing for assembling various types of small-sized products; and a method and an apparatus for manufacturing the fastener. The fastener (10) such as a nut, an insert, etc. is to be fastened with a screw tool (30) such as a screw, a bolt, etc; and a concavity (18) is formed by press-forming from the outside in a part of the outer circumferential wall of the fastener to form a reduced-diameter deformation part (20) where the diameter of the crest or bottom of the female thread is partially reduced in the inner circumferential wall of the fastener.</p> |
