Abstract: A spreader dowel includes a sleeve having an area formed with an internal first thread for engagement by a screw. The sleeve has opposite ends and includes first longitude slots on one end for defining an expansion zone. A spreader piece formed with a conical portion is connected to the screw and spreads the expansion zone, when the screw is inserted. The sleeve has second longitude slots which extend inwardly from an end face on the other end. In the region of the second longitude slots toward the end face, the sleeve has a zone which is formed with an internal second thread defined by a thread diameter which is smaller than a thread diameter of the screw while having a same pitch as the thread diameter of the screw, or is threadless with a clear diameter which is smaller than an outer diameter of the screw.

Abstract: A spreader dowel includes a sleeve having an area formed with an internal first thread for engagement by a screw. The sleeve has opposite ends and includes first longitude slots on one end for defining an expansion zone. A spreader piece formed with a conical portion is connected to the screw and spreads the expansion zone, when the screw is inserted. The sleeve has second longitude slots which extend inwardly from an end face on the other end. In the region of the second longitude slots toward the end face, the sleeve has a zone which is formed with an internal second thread defined by a thread diameter which is smaller than a thread diameter of the screw while having a same pitch as the thread diameter of the screw, or is threadless with a clear diameter which is smaller than an outer diameter of the screw.