| 摘要 |
The dowel (1) is divided into a spreading segment (4) located at its lower end and the upper area (5) with a flat head (6) on top. A transitional segment (12) between both parts (4, 5) is designed as a cylindrical part made of a thin material (7) and surrounded by a helical elevation (8). When the screw, inserted into the dowel, (1) is tightened the central area (12) is compressed, resulting in only a slight radial extension. |
