| 摘要 |
PROBLEM TO BE SOLVED: To provide a nail free of looseness with a secular change and easy to extract with continuous reverse turn as in a wood screw, having high joining force on a joined object such as a wood material. SOLUTION: The nail 1 comprises a positive or negative groove 6 provided in the head for a driver to be used, a spiral screw form 4 provided at the upper end of a nail body 2, and a protruded screw piece 3 arranged at one columnar lower end in one vertically long line. It has a conical front end 5 in a sharp-pointed condition. COPYRIGHT: (C)2005,JPO&NCIPI
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