| 摘要 |
<p>The invention concerns an anchoring screw comprising a screw body (1), which is formed with threads over at least a portion of its extension, a screw head (2) securely fastened at one end of the screw body, and an expandable retention element (3), which retention element is mounted on the threaded portion of the screw body for rotation thereon by means of corresponding threads and which is arranged to expand when displaced in the direction towards the screw head relative to a surrounding material in which it is to be secured. It is characteristic of the screw that the screw head (2) is formed with faces (21) designed to be brought into engagement with a tool for rotation of the screw, at least one of said faces formed with an undercut relative to the screw axis, whereby it becomes possible to use the tool not only to transmit a rotary force but also to exert a pulling force on the screw body in the direction towards the screw head.</p> |
