Split plastics spreading dowel - has truncated trapezoidal ridged shaft with tongues and deformable fins

摘要

The plastics spreading dowel for plugging a hole in a wall has a stepped ridged shaft and is in two symmetrical halves with a central slot. Two projecting tongues (9) are fastened to the dowel shaft in a plane normal to the central slot. Each ridge has a gentle taper in the insertion direction, and may have rounded corners. The dowel has a conical bore (15) in its outer end, and there are fins (16) projecting from the dowel surface, in the same plane as the flexible tongues (9), but further up the shaft away from the tip. These fins (16) are curved away from the direction of rotation. When the dowel is inserted in a hole, the tongues are pushed back, and the fins squashed against the hole wall.