Method and device for the length rectification of a foil strip of a material which shrinks during cooling in machines for the production and separation of packages

US4894977A · kind A · utility

Assignee

• Josef Uhlmann Maschinenfabrik GbmH & Co. KG · DE

Inventors

• Herbert Rittinger · Laupheim, DE
• Dieter Janek · Laupheim, DE
• Peter Auer · Ottobrunn, DE
• Rudolf Scheffold · Laupheim, DE

Key dates

• Filing date: May 8, 1987
• Grant date: Jan 23, 1990
• Expiry date: May 8, 2007

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B65H20/18
• WIPO field: Handling
• WIPO sector: Mechanical engineering

Abstract

The invention is related to a machine for the production and separation of packages, which packages are formed through deep-drawing from a foil strip transported through a forming station and a separating station of the machine and are then punched out. The foil strip is heated prior to deep-drawing and undergoes a cooling in its travel between the forming station and the separating station. When a transport interruption occurs, the still warm foil strip is stretched between the forming station and the separating station so much, and optionally the size of the elongation is controlled timewise in such a manner that, when the machine is restarted, the foil strip, in spite of the increased cooling which has taken place in the meantime, does maintain the same length as the still warm foil strip at the beginning of the machine interruption. The stretching process prevents the otherwise increased shrinking of the foil strip occurring during the interruption thereby avoiding packaging failures when the machine is restarted after the interruption.