Abstract: In order to improve the holding force of a self-tapping concrete screw (1) in a hole (2) drilled in concrete (3), the invention proposes formation of the concrete screw (1) with two threads (8, 9) having different external diameters (d1, d2), the spacing (p1) of the thread (8) which has the smaller external diameter (d1) to the thread (9) which has the larger external diameter (d2) when seen from the front end (5) of the screw being smaller than the spacing (p2) of the thread (9) having the larger external diameter to the thread (8) having the smaller external diameter. The threads (8, 9) are preferably sawtooth threads.

Abstract: The invention relates to a method for anchoring an anchor (10) in an anchoring substrate (26), for example, of concrete, to an anchor (10) suitable for the method and to a drill suitable for the method. The invention proposes using the anchor (10) as tool for at least partial preparation of the anchoring hole (28) in the anchoring substrate (26) by high-frequency oscillatory working. The anchor (10) is, for example, an undercut expansion anchor, the expansible sleeve (14) of which forms the tool and is driven into an anchoring substrate (26) by being subjected to the action of high-frequency oscillations.

Abstract: The invention relates to an undercut anchor (10) comprising an anchor shaft (12) and a non-circular, for example triangular, anchor head (16). Said undercut anchor (10) is to be anchored in a borehole which is produced by ultrasound boring, has a cross-section matching that of the anchor head (16), and an undercut at the bottom thereof, that engages at the rear of the anchor head (16) following a rotation of 60°. A rotation-preventing element (18) is used to ensure that the anchor is rotationally fixed, said element having a cross-section matching the anchor head (16), and a recess (22) arranged on a front side thereof facing the anchor head (16) and corresponding thereto (16). When the anchor head (16) engages with the undercut of the borehole following the rotation, the rotation-preventing element (18) slides towards the anchor head (16) with the recess (22) thereof, holding the anchor head (16) in the borehole in a rotationally fixed manner, and thus securing the anchoring.

Abstract: The invention relates to an expansible anchor (1) made of metal for affixing a component to a substrate. Known expansible anchors (1) have an anchor element (3) with fixing means (4) and an expansion zone (5) of reduced diameter which widens in the direction of insertion of the expansible anchor. An expansion sleeve (6) having expansion tongues (8) and at least one cutter (9) for creating an undercut is mounted on the expansion zone (5) so as to be axially displaceable. In order to reduce the manufacturing costs for such an expansible anchor (1), the invention proposes that the expansion sleeve (6) consists of hardened steel and the predetermined bending lines (10) are straight. The invention also proposes a setting tool (2) for setting such an expansible anchor (1), which has key-surfaces (16), a driving surface (17) and an adapter device (18).