| 摘要 |
<p>A combination of a screw with a screwdriver bit capable of effectively preventing the cam-out event of the screwdriver bit by improving the formation of a groove part in the cross groove of the screw so as to prevent the screw from being damaged and capable of remarkably increasing a working efficiency by always achieving an appropriate and rapid screw tightening operation even if the cross groove portion of the screw is damaged, and a header punch for manufacturing the screw, the header punch comprising the screw (30) having cutout step parts (36) of generally right triangle shape in cross section provided at the center parts of the tilted groove parts (32a) of a bit fitted groove (32) formed in a cross groove at a screw head part (30a) and a screwdriver bit (50) having projected parts (56) of generally triangle in cross section matching the cutout step parts formed at the center part of the tilted groove parts of the screw provided at the center part of the tilted end edge parts (52a) of a flat-shaped blade part (52) and having the tip faces of the blade part (52) formed as conical projected parts (54).</p> |
