| 摘要 |
A screw with a polygonal hole (30) formed with a polygonal hole (32) disposed in the center of a screw head (30a) and comprising a vertical wall (33) with a preset depth, and with a cone bast oriented from the lower edge of th e vertical wall toward the center of a screw neck, wherein a vertical step forming an inscribed circle of the polygon is provided at the lower edge (33a) of th e vertical wall (33) of the polygonal hole (32) formed in the screw head (30a) , the cone base (35) oriented from the lower edge (34a) of the vertical step (34) toward the center of the screw neck is formed, and a driver bit (40) or wren ch (41) to be fitted to this screw is provided at the tip of a peak edge (42) with a cylindrical projection (44) forming the inscribed circle of the polygon.</SD OAB> |
