Patent ID: 6086302
Filing Date: 2000-07-11
Classification: F16B

Abstract:
A self-tapping concrete screw adapted for insertion in an associated drill hole in concrete, comprisinga substantially cylindrical core (1) having a central longitudinal axis (12) and an insertion end (2) adapted to be inserted into the associated drill hole with a nominal diameter, and a head end with a screw head (4), and a core diameter d;a thread (5) with flanks (6, 7) and a periphery and a lead angle a, which thread (5) is formed in a single piece with the core (1);a tapping thread section (10a) extending from the insertion end (2) including two to four flights of the thread (5) having a maximum outer diameter D and provided with cutting notches (10) disposed in the vicinity of the periphery of the thread (5) and designed in the shape of triangles open towards the periphery and having a root and a radial length h and wherein the flanks (6, 7) extend substantially in parallel to each other radially to the central longitudinal axis (12); anda non-tapping thread section (5a) extending from the tapping thread section (10a) and having an outer diameter D"" of the thread (5), which outer diameter is reduced by 0.1 to 0.2 mm with respect to the maximum outer diameter D of the tapping thread section.