| 摘要 |
<p>Method for the production of a double collar by deep drawing, spinning, bending or the like of a sheet made of metal or a ductile alloy, in which a piece of sheet is placed between a first punch and a die which has, in the region of the first punch, a cut-out with a circumferential shape corresponding approximately to the cut-out, the first punch is pressed on to the die, a bulge which protrudes relative to the sheet and the outer border of which is annular thereby being formed in the cut-out of the die, the central area bounded by the annular border of the bulge being perforated centrally by means of a second punch, which is arranged on the same side as the die, the sheet resting at the circumference of the perforated area, on a counterpart, a first bead being formed along the border of the bulge during this punching operation, and the second punch is displaced relative to the sheet in order to bring the metal in the central area towards the annular border of the bulge, a second bead on the opposite side of the sheet to the first bead becoming evident due to this displacement.</p> |
