Thermo-forming packaging machine with adjustable chain guide

Abstract

The invention relates to a thermo-forming packaging machine and a method for automatic adjustment of chain guides in order to be able to change over in certain sections between chain guides being aligned parallel and converging to each other so that both shrinkable as well as non-shrinkable lower films can be processed on only one thermo-forming packaging machine.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This Application claims priority to European Patent Application Number 13193125.5 filed Nov. 15, 2013, to Christian Lau and Elmar Ehrmann entitled “Thermo-Forming Packaging Machine with Adjustable Chain Guide,” currently pending, the entire disclosure of which is incorporated herein by reference.FIELD OF THE INVENTION[0002]The invention relates to a thermo-forming packaging machine and to a method for operating a thermo-forming packaging machine.BACKGROUND OF THE INVENTION[0003]A thermo-forming packaging machine is known from DE 1 586 180 which discloses manual parallel adjustment of the chain guides relative to each other to adjust the distance of the chain guides to different film widths.[0004]DE 10 2008 016 243 A1 discloses a thermo-forming packaging machine with a chain guide in a loading stretch adjustable by using pneumatic cylinders. The adjustment is provided for relaxing the film transverse to the direction of transport in order ...

AI Technical Summary

Benefits of technology

The present invention is about improving a thermo-forming packaging machine so that it can process both shrinkable and non-shrinkable films. The machine has two forming stations, a loading stretch, and a sealing station for closing the trays filled with a product with a top film. The lower film can be transported by two clamping chains, which can be adjusted using a controller and power-operated actuators. This allows the processing of both shrinkable and non-shrinkable lower films without any retooling or manual activities by the operator on the chain guide sections. The flexibility of the machine is thereby increased. The machine can also have sensors to detect transverse tension and automatically adjust the actuators or chain guide sections to avoid wrinkling of the lower film. In an alternative embodiment, the controller is configured to perform the adjustment of the chain guide sections in dependence on the power input of the transport drive of the clamping chains. This is a simple structural design, because information about current or power input is readily available.

Problems solved by technology

Without a converging chain guide, the clamping chains disposed on both sides would as a film transport device not be able to hold the film shortened in the transverse direction.

Adjusting the transverse tension along the chain guide is difficult and requires much skill and experience, as inter alia transverse tension is not measurable.

These packaging machines have the further drawback that they can only be used for PP or PS films, since processing polyethylene terephthalate (PET), polyamide (PA), or polyethylene (PE) films require a continuous parallel chain guide as these films exhibit little or no shrinkage after the molding process.

Processing such non-shrinkable films is not possible in a known thermo-forming packaging machine with an at least partially convergingly aligned chain guide.

Images