| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a quick cuttable screw which reduces twist force when screwing and suppresses cracks in an article during screwing. <P>SOLUTION: The quick cuttable screw comprises a screw head, a screw shaft extending outward from the screw head, and screw teeth formed by providing a plurality of screw threads around the screw shaft. Each screw tooth is composed of a non-circular shape, and is designed to have arcs of intercepts two of which are symmetrically arranged on the screw thread. When an article is cut by the screw teeth, frictional force between the screw and the article is reduced, twist force upon screwing is reduced, while a screwing speed is increased. The screw teeth in a non-circular shape generates a space for discharging chips on the article in a cutting process, which enhances an effect of discharging chips and prevents cracks in the article during the screwing process. When the arcs of the intercepts are designed to have non-equivalent length from each other, an effect of preventing the screw from returning after being screwed is obtained. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
