| 摘要 |
<p>The present invention relates to a screw having a starshaped socket hole in a top surface of the screw head. The star-shaped socket hole has the form of the figure formed by concentric superposition, 45.degree. out of phase, of two equilateral octagons intermediate in configuration between a regular octagon and a square. The screw can sustain high tightening torque values, and reduces the risk of chipping and deformation in the screw head whilst facilitating the fitting of a screwdriver in the socket hole of the screw.</p> |
