| 摘要 |
The invention relates to a method whereby a preformed metal lid which is intended for a tin, e.g. a paint tin, and of which at least one peripheral portion is axially deepened, is formed with a radially outwardly inverted peripheral edge with respect to the lid axis. The object of this invention is to provide a method in which the outwardly inverted peripheral edge can be formed with very close dimensional tolerances. To this end the invention provides a method of the type referred to hereinbefore, which is characterized in that the lid is held in tightly fitting relationship in all directions in a multipart die at least by its deepened peripheral portion, except in the zone where the inverted peripheral edge is to be formed and at least at the inside of the base of said peripheral portion, and said base is pressed by art of the die acting as a punch against the part of the die situated opposite the inside of the base. |
