Screwed connection for extruded sections - has self-tapping threaded inserts fitted into holes with longitudinal serrations

摘要

The extruded sections which are joined to an angle section are provided with longitudinal ribs with a central serrated hole which communicates with a longitudinal slot. The peaks which are symmetrical about the radial lines (M) alternate with the valleys which are symmetrical about the radial lines (n). A bush with both internal and external threads and which has the outside diameter equal to the diameter of the hole at the bottom of the velleys is forced with a rotary motion into the hole and in so doing a matching thread is cut in the extrusion. The internal thread can then be used with a conventional screw.