Expanding socket for bracing dowel is braced by screw with thread with rear flank in screw-in direction having surface angle of forty-five degrees or lens to axial direction of screw

摘要

The bracing dowel has an expanding socket braced by a screw (14) with a thread (30) with a rear flank (32) in the screw-in direction having a surface angle of forty-five degrees or less to the axial direction of the screw. The screw thread over its length from the front to the rear has an increasing core diameter. The screw thread has a saw-tooth profile, with a steeper and shorter flank (34) at the front in the screw-in direction and a flatter and longer flank (32) at the rear.