| 摘要 |
PROBLEM TO BE SOLVED: To provide a nut for tightening having excellent strength and capable of obtaining stable tightening force in a short time always. SOLUTION: This nut for tightening is composed of a cylindrical body 2 having a screw-fitting screw part 1 at the inner periphery, a reverse conical part 3 provided at a terminal on the opposite side for preceding screw-fitting so as to enlarge outside diameter sequentially from the halfway of an outer peripheral face of the cylindrical body, a collar part 4 provided by protruding in the peripheral direction from a peripheral fringe part having the maximum diameter of the reverse conical part, an engaging part in which a bit of an impact wrench provided on a terminal face of the reverse conical part is detachably fitted and engaged, a plurality of first cutting blades 6 provided toward a section having the maximum diameter from a section having the minimum diameter of a peripheral face of the reverse conical part and inclined forward from the direction of rotation, and a second cutting blade 7 continuous with the first cutting blade and provided by inclining backward in the direction of rotation toward a peripheral fringe of a rear face of the collar part. COPYRIGHT: (C)2006,JPO&NCIPI
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