Method for unrolling web material in a packaging machine and packaging machine

Abstract

A method for unrolling web material in a packaging machine operating intermittently in a cycle with web material is provided. The method includes the step: unrolling a predetermined length of web material to be processed ( 6 ) from a supply roll ( 1 ) and receiving it in a first storage ( 2 ) arranged upstream of a working station ( 3 ) in the processing direction, when the working station ( 3 ) is operative; and the step: supplying web material to be processed ( 6 ) from the first storage ( 2 ) to the working station ( 3 ) and simultaneously transporting processed web material ( 6 ′) away from the working station ( 3 ), when the working station ( 3 ) is inoperative.

1 . Method for unrolling web material in a packaging machine operating intermittently in a clocked way with web material, comprising the steps: 
 unrolling a predetermined length of web material to be processed ( 6 ) from a supply roll ( 1 ) and receiving it in a first storage ( 2 ) arranged upstream of a working station ( 3 ) in the processing direction as well as transporting processed web material ( 6 ′) away from a second storage ( 4 ) arranged downstream of the working station ( 3 ) in the processing direction, when the working station ( 3 ) is operative;    supplying web material to be processed ( 6 ) from the first storage ( 2 ) to the working station ( 3 ) and simultaneously transporting processed web material ( 6 ′) away from the working station ( 3 ) and receiving it in the second storage ( 4 ), when the working station ( 3 ) is inoperative.    
   
   
       2 . Method according to  claim 1 , wherein in the step of transporting away from the second storage ( 4 ) the processed web material ( 6 ′) is supplied to a removal device ( 5 ) and wound-up thereon.  
   
   
       3 . Method according to one of claims  1  or  2 , wherein cutting-out of portions of the web material ( 6 ) is performed in the working station when the working station ( 3 ) is operative.  
   
   
       4 . Method according to one of  claims 1  to  3 , wherein the processed web material ( 6 ′) which is transported away is a remaining frame of waste web material.  
   
   
       5 . Method according to one of  claims 1  to  4 , wherein the web tension is substantially maintained constant during the entire method.  
   
   
       6 . Method according to one of  claims 1  to  5 , wherein fixation of the web material ( 6 ) at the input side of the working station ( 3 ) is effected when the working station ( 3 ) is operative.  
   
   
       7 . Method according to one of  claims 1  to  6 , wherein steps requiring mass acceleration of the supply roll ( 1 ) and of the removal device ( 5 ) are only performed when the working station ( 3 ) is operative.  
   
   
       8 . Method according to one of  claims 1  to  7 , with further the step: 
 adjusting the length of web to be transported before processing web material ( 6 ).    
   
   
       9 . Packaging machine which is constructed for intermittent clocked transport of web material, with: 
 a supply roll ( 1 ) for supplying web material ( 6 ) to be unrolled,    a first storage device ( 2 ) for receiving a predetermined length of supplied web material ( 6 ),    a working station ( 3 ) which receives web material ( 6 ) supplied intermittently in a clocked way and outputs processed web material ( 6 ′),    a second storage device ( 4 ) for receiving a predetermined length of processed web material ( 6 ′) output from the working station ( 3 ),    a removal device ( 5 ) for removing processed web material ( 6 ′) from the second storage device ( 4 ), and    a control device controlling the packaging machine such that web material to be processed ( 6 ) is supplied from the supply roll ( 1 ) to the first storage device ( 2 ) and processed web material ( 6 ′) is transported from the second storage device ( 4 ) to the removal device ( 5 ) when the working station ( 3 ) is operative, and such that web material to be processed ( 6 ) is transported from the first storage device ( 2 ) into the working station ( 3 ) and processed web material ( 6 ′) is transported from the working station ( 3 ) into the second storage device ( 4 ) when the working station ( 3 ) is inoperative.    
   
   
       10 . Packaging machine according to  claim 9 , wherein the removal device ( 5 ) is a roll for winding-up processed web material ( 6 ′).  
   
   
       11 . Packaging machine according to one of claims  9  or  10 , wherein the working station ( 3 ) is a sealing and cutting station.  
   
   
       12 . Packaging machine according to one of  claims 9  to  11 , wherein the first storage device ( 2 ) and the second storage device ( 4 ) are mechanically coupled to each other.  
   
   
       13 . Packaging machine according to one of  claims 9  to  12 , wherein the first storage device ( 2 ) and the second storage device ( 4 ) are adjustable to receive a predetermined length of web material ( 6 ,  6 ′).  
   
   
       14 . Packaging machine according to one of  claims 9  to  13 , wherein the first and second storage devices ( 2 ,  4 ) each store the web material ( 6 ,  6 ′) in form of a loop.  
   
   
       15 . Packaging machine according to one of  claims 9  to  14 , wherein the coupling of the first and second storage devices is realized by a strand of chain ( 7 ) or a belt.  
   
   
       16 . Packaging machine according to  claim 15 , which is formed 
 such that the strand of chain ( 7 ) or belt is moved in one direction ( 73 ) for filling the first storage device ( 2 ) and for emptying the second storage device ( 4 ) when the working station ( 3 ) is operative and    such that the strand of chain ( 7 ) or belt is moved in the opposite direction ( 72 ) for supplying web material to be processed ( 6 ) to the working station ( 3 ) and for removing processed web material ( 6 ′) from the working station ( 3 ) when the working station ( 3 ) is inoperative.    
   
   
       17 . Packaging machine according to one of  claims 9  to  16 , wherein the first and second storage devices ( 2 ,  4 ) are each formed by two fixed rolls ( 20 ,  21 ;  40 ,  41 ) and a shiftable roll ( 22 ;  42 ) movable relative thereto.  
   
   
       18 . Packaging machine according to one of  claims 10  to  17 , wherein the supply roll ( 1 ) and the removal device ( 5 ) each comprise a drive mechanism ( 10 ,  50 ) rotationally driving them.