Abstract: 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an inner profile coacting with an outer profile of the expansion screw for expanding the sleeve when the screw (1) is withdrawn from the sleeve.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.

Abstract: An expanding bolt for attachment to the walls of a cavity, which bolt is threaded at its outer end for cooperation with a nut, and at its inner end is formed to a cone. The cone is surrounded by an expanding sleeve, one edge of which is continuous and oval and the other edge of which is split into a number of pointed tips, some of which are longer than the others.