| 摘要 |
<p>A screw includes a socket adapted to receive the tip of a screwdriver. The socket is tapered and formed by a plurality of sides interconnected by rounded corners. Each side is configured as a surface of a segment of a cone having a cone angle of at least three degrees. The screwdriver tip is configured correspondingly to the screw socket. The screwdriver may be mounted in a power driven rotary arm and spring-biased, whereby a tightened screw applies a rearward reaction force to the screwdriver, causing the tip to be displaced from the screw socket and thereby limit the torque applied to the screw.</p> |
