| 摘要 |
PROBLEM TO BE SOLVED: To prevent a nail from slipping off by vibration and the like by constituting a shaft part with a screw part whose lead angle is not constant along a longitudinal direction, and recessed/projection parts which are not formed in a screw shape of a head part side. SOLUTION: A part 12a of a shaft part 11 of a nail 1 is formed as a screw part A formed with a plurality of grooves having a lead angleα, and a part 12b is formed as a screw part B formed with a plurality of grooves having a lead angleβ. A plurality of parts 12c are annular bodies along a circumferential direction as recessed/projection parts which are not formed in a screw shape. In the relation between respective lead anglesαandβ, the angleβis larger than the angleα. Namely, a strike resistance is reduced when the nail 1 is struck, in the screw part B (12b), and a pull-out resistance is increased in the screw part A (12a). The nail 1 is slipped out while turning by vibration and the like, the nail 1 is difficult to turn since the lead angleαof the screw part A (12a) is smaller than the lead angleβof the screw part B (12b). As a result, the nail 1 is difficult to slip off.
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