| 摘要 |
<p>In the zone of the surfaces which will be visible when a welded butt joint is made between hollow profiles of synthetic material, the edges to form the visible joint are set back relatively to the edges to be welded, by an amt. corresp. to the material required for the weld. The projecting edges of the profile are then raised to the welding temp and the profiles are pressed together so that the setting back of the visible edges is eliminated and the welded seam is formed underneath. Setting back of the edges is effected by a milling cutter, and the machining to size and the setting back are carried out in one operation. The walls of the core forming the welds are thicker than the circumferential walls of the profile, and the distance of these walls from the visible outer walls is such that the welded seam made lies against the butting edges of the outer walls which are filled by a glue. Frames for doors and windows can thus be assembled without it being necessary to have an additional operation for trimming off the visible welded seams.</p> |
