Film store and method for storing a strip-like continuous film

Abstract

The invention relates to a film store and method for dynamically storing a strip-like label film, wherein the film store comprises at least one storage region with an upper carriage and a lower carriage as well as deflection rollers fastened thereto for the label film. The label film is guided along a transport path extending in a meandering manner between the upper carriage and the lower carriage, and the size of the film store is adjusted by the upper and lower carriage moving in opposite directions while mutually compensating for weight. Because the upper carriage and the lower carriage are moved toward one another or away from one another by a torque-controlled or force-controlled servo motor and/or the servo motor tensions the label film between the deflection rollers, the storage dynamics and the storage capacity can be optimized while maintaining a maximum permissible strip tension in the label film.

1 . A film store for a strip-like continuous film, comprising:
 at least one storage region with an upper carriage and a lower carriage; and   deflection rollers fastened to the upper carriage and the lower carriage in such a way that the deflection rollers guide the continuous film along a transport path extending in a meandering manner between the upper carriage and the lower carriage,   wherein the upper carriage and the lower carriage are coupled to one another in a mutually weight-compensating manner so as to be movable in opposite directions in order to adjust a size of the at least one storage region,   wherein the at least one storage region comprises a torque-controlled or force-controlled servo motor for movement of the upper carriage and the lower carriage in opposite directions and/or for tensioning the continuous film between the deflection rollers.   
     
     
         2 . The film store of  claim 1 , wherein the servo motor is designed as a direct drive for a toothed belt which is fixedly connected to the upper carriage and the lower carriage, or as a direct drive for at least one of the upper carriage and the lower carriage, wherein the direct drive is in a form of a rotation servomotor for driving the toothed belt or is in a form of at least one linear servomotor rigidly coupled to one of the upper carriage or the lower carriage. 
     
     
         3 . The film store of  claim 1 , further comprising an electronic control device configured to:
 calculate frictional resistances and/or moments of inertia of the upper carriage and the lower carriage occurring during the movement of the upper carriage and the lower carriage in opposite directions;   calculate, based thereon, a portion of a target torque of the servo motor or of a target force of the servo motor associated with the size adjustment of the at least one storage region; and   control the servo motor based thereon.   
     
     
         4 . The film store of  claim 3 , wherein the electronic control device is further configured to specify the target torque or the target force of the servo motor, taking into account the portion associated with the size adjustment and a portion associated with a strip tension of the continuous film. 
     
     
         5 . The film store of  claim 4 , wherein the at least one storage region comprises an output-side storage region and an input-side storage region serially connected upstream thereof by means of at least one conveyor unit, wherein the conveyor unit for conveying the continuous film is designed with simultaneous decoupling of the strip tension prevailing in the output-side storage region and the input-side storage region. 
     
     
         6 . The film store of  claim 5 , wherein the output-side storage region is smaller than the input-side storage region. 
     
     
         7 . The film store of  claim 6 , wherein the input-side storage region comprises an input-side conveyor unit for the continuous film, and the electronic control device is configured to adjust a conveying speed of the input-side conveyor unit to an output-side conveying speed of the at least one storage region. 
     
     
         8 . The film store of  claim 7 , wherein the electronic control device is configured in such a way that the input-side conveying speed follows the associated output-side conveying speed with reduced acceleration or deceleration or a reduced jerk with respect thereto. 
     
     
         9 . The film store of  claim 7 , further comprising an output-side conveyor unit arranged downstream of the output-side storage region and the input-side storage region, wherein the electronic control device is designed to adjust the conveying speeds of the input-side conveyor units in a cascading manner starting from the conveying speed of the output-side conveyor unit counter to a strip running direction. 
     
     
         10 . A device for providing a continuous film, comprising a device for automatically alternately feeding film from supply rolls connected in parallel, and the film store of  claim 1 . 
     
     
         11 . A method for dynamically storing a strip-like continuous film in a film store comprising at least one storage region with an upper carriage and a lower carriage as well as deflection rollers for the continuous film fastened to the upper carriage and the lower carriage, the method comprising:
 guiding the continuous film along a transport path extending in a meandering manner between the upper carriage and the lower carriage; and   adjusting a size of the at least one storage region by operation by the upper carriage and the lower carriage moving in opposite directions while mutually compensating for weight, wherein the upper carriage and the lower carriage are moved toward one another or away from one another by a torque-controlled or force-controlled servo motor and/or the servo motor tensions the continuous film between the deflection rollers.   
     
     
         12 . The method of  claim 11 , wherein controlling the servo motor comprises:
 automatically calculating frictional resistances and/or moments of inertia of the upper carriage and the lower carriage occurring during the movement of the upper carriage and the lower carriage in opposite directions;   automatically calculating a portion of a target torque or of a target force of the servo motor associated with the size adjustment of the at least one storage region; and   controlling the servo motor based on the automatic calculations.   
     
     
         13 . The method of  claim 12 , wherein conveying speeds of conveyor units for the continuous film delimiting the at least one storage regions are controlled in a cascading manner starting from an output-side conveying speed of the film store counter to a strip running direction. 
     
     
         14 . The method of  claim 13 , wherein a maximum strip tension in the continuous film is limited by the torque control or force control of the servo motor via a specification of format-specific minimum and/or maximum values. 
     
     
         15 . The method of  claim 14 , wherein the output-side conveying speed of the film store follows a speed profile of the continuous film which is specified downstream thereof, and storage dynamics caused thereby in an output-side storage region of the at least one storage region is reduced by a control cascade in at least one upstream-arranged storage region of the at least one storage region of the film store in such a way that more continuous film can be stored while maintaining a maximum permissible strip tension than in the output-side storage region. 
     
     
         16 . The method of  claim 13 , wherein the output-side conveying speed of the film store follows a speed profile of the continuous film which is specified downstream thereof, and storage dynamics caused thereby in an output-side storage region of the at least one storage region is reduced by a control cascade in at least one upstream-arranged storage region of the at least one storage region of the film store in such a way that more continuous film can be stored while maintaining a maximum permissible strip tension than in the output-side storage region. 
     
     
         17 . The method of  claim 11 , wherein conveying speeds of conveyor units for the continuous film delimiting the at least one storage regions are controlled in a cascading manner starting from an output-side conveying speed of the film store counter to a strip running direction. 
     
     
         18 . The method of  claim 11 , wherein a maximum strip tension in the continuous film is limited by the torque control or force control of the servo motor via a specification of format-specific minimum and/or maximum values. 
     
     
         19 . The film store of  claim 1 , wherein the at least one storage region comprises an output-side storage region and an input-side storage region serially connected upstream thereof by means of at least one conveyor unit, wherein the conveyor unit for conveying the continuous film is designed with simultaneous decoupling of the strip tension prevailing in the output-side storage region and the input-side storage region. 
     
     
         20 . The film store of  claim 19 , wherein the input-side storage region comprises an input-side conveyor unit for the continuous film, and the film store comprises an electronic control device configured to adjust a conveying speed of the input-side conveyor unit to an output-side conveying speed of the at least one storage region.