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.

What is claimed is: 
     
         1 . Thermo-forming packaging machine comprising:
 a forming station for molding trays into a lower film;   a loading stretch;   a sealing station for closing said trays filled with product with a top film;   clamping chains disposed on both sides of said lower film for transporting said lower film;   chain guide sections for guiding said clamping chains; and   a controller and power-operated actuator for adjusting at least one said chain guide section transverse to a direction of production.   
     
     
         2 . Thermo-forming packaging machine according to  claim 1 , wherein two oppositely disposed said chain guide sections are adjustable to converge to each other. 
     
     
         3 . Thermo-forming packaging machine according to  claim 1 , wherein said chain guide sections are disposed downstream of said forming station. 
     
     
         4 . Thermo-forming packaging machine according to  claim 1 , wherein said actuator comprises at least one of a pneumatic cylinder, a lifting spindle drive, and a servo motor. 
     
     
         5 . Thermo-forming packaging machine according to  claim 1 , wherein said actuator comprises a pneumatic cylinder and at least one lifting stroke limiter is provided by one adjustable end position. 
     
     
         6 . Thermo-forming packaging machine according to  claim 5 , wherein said adjustable end position is provided in or at said pneumatic cylinder. 
     
     
         7 . Thermo-forming packaging machine according to  claim 1 , wherein an adjustment range for said actuator is provided of up to 12 mm. 
     
     
         8 . Thermo-forming packaging machine according to  claim 1 , wherein a plurality of said chain guide sections disposed consecutively in the direction of production are adjustable. 
     
     
         9 . Thermo-forming packaging machine according to  claim 1 , wherein said controller is configured to store a position of said actuator in recipes and to adjust said chain guide sections accordingly when recipes are changed. 
     
     
         10 . Thermo-forming packaging machine according to  claim 1  further comprising sensors to detect tension stress transverse to the direction of production. 
     
     
         11 . Thermo-forming packaging machine according to  claim 10 , wherein said sensors are each disposed between an actuator and a chain guide section. 
     
     
         12 . Thermo-forming packaging machine according to  claim 1 , wherein said controller is configured to perform the adjustment of said chain guide sections in dependence on a power input of a transport drive of said clamping chains. 
     
     
         13 . Method for operating a thermo-forming packaging machine, said method comprising the steps of:
 providing said thermo-forming packaging machine that comprises consecutively in the direction of production:
 a forming station for molding trays into a lower film; 
 a loading stretch; and 
 a sealing station for closing said trays filled with product with a top film; 
   transporting said lower film by two clamping chains disposed on both sides of said lower film;   guiding said clamping chains in a plurality of chain guide sections, wherein at least one said chain guide section is adjustable transverse to a direction of production; and   adjusting at least one of two oppositely disposed said chain guide sections by use of a controller and power-operated actuator so that said two oppositely disposed chain guide sections are brought from an orientation that is generally parallel to each other into an orientation that is converging to each other.   
     
     
         14 . Method according to  claim 13 , wherein said step of adjusting at least one said chain guide section is performed by said controller in dependence of a transverse tension of said lower film acting upon said chain guide sections. 
     
     
         15 . Method according to  claim 14 , wherein said transverse tension is detected using at least one sensor. 
     
     
         16 . Method according to  claim 14 , wherein said transverse tension is detected indirectly via a power input of a transport drive of said clamping chains 
     
     
         17 . Method according to one of the  claim 14 , wherein a range for said transverse tension to be set is entered and stored in said controller.