| 摘要 |
PCT No. PCT/SE80/00334 Sec. 371 Date Jul. 20, 1981 Sec. 102(e) Date Jul. 20, 1981 PCT Filed Dec. 16, 1980 PCT Pub. No. WO81/01870 PCT Pub. Date Jul. 9, 1981.An expansion screw for being secured in a cavity is threaded at the outer end of its screw portion for co-action with a nut (2) and is provided with an expandable sleeve (10) about its opposite end. The sleeve has an inner profile coacting with an outer profile of the expansion screw for expanding the sleeve when the screw (1) is withdrawn from the sleeve. The outer profile of the screw portion (1) is formed by a plurality of coaxial cones (3-6) with intermediate cylindrical junction portions (7-10), all cones and junction portions being integral with the rest of the screw portion. The inner profile of the sleeve (10) is formed by thickened regions (12), projecting inwards from the inner surface of the sleeve and corresponding to the cylindrical junction portions, and by thinner regions (13) of the sleeve corresponding to the coaxial cones. The thickness of the sleeve is adapted to allow portions of it to be expanded by the cones into bulges (37) extending around the sleeve, the bulges being intended to penetrate into the wall of the cavity for securing the expansion screw therein. |
