method for attaching loops and / or columns on a sheet, the sheet with loops and / or columns and rechteckrohr from sheet

摘要

The lugs (13,14) or protrusions are at right angles to the metal surface and extend for further than the thickness of the latter. The method involves using a punch and die to loading the metal beyond the yield point. Part of the metal can be pressed into recesses in the punch and/or die, which forms the negative mould for the lugs or protrusions. Formation can be by punch and die at intervals, while the sheet-metal strip is indexed forward.