| 摘要 |
PROBLEM TO BE SOLVED: To tighten a fastened material by surely preventing missing of a head, a fracture of a thread section, idling of a drill or the like without reducing operating efficiency. SOLUTION: In a drilling tapping screw 1 having a head 2, a thread section 3 interconnecting with the head 2, and a drill section 4 interconnecting with the thread section 3, a plurality of braking ribs 21, of which the heights and widths are reduced outward from their centers and braking faces at approximately 90 degrees are prepared to a screwed direction, are formed on a seating face of the head 2 peripherally at regular intervals. COPYRIGHT: (C)2005,JPO&NCIPI
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