Systems and methods for supplying a web of packaging material to an indexing-motion packaging machine

Abstract

Methods and systems for supplying a web of packaging material to an indexing-motion packaging machine include rotating a roll of a web of packaging material, sensing changes in position of a dancer caused by rotation of the roll, rotating the roll at a starting speed of rotation that is based upon sensed changes in position of the dancer, and then maintain substantially constant tension in the web of flexible packaging material during indexing motion of the packaging machine.

1 . A system for supplying a web of packaging material to a packaging machine, the system comprising:
 a motor rotating a roll of a web of packaging material;   a conveyor conveying the web from upstream to downstream;   a dancer located downstream of the roll and upstream of the conveyor, the dancer being movable between first and second positions based upon a change in tension of the web; and   a control circuit controlling the motor and being in communication with at least one sensor sensing the position of the dancer;   wherein the control circuit controls the motor to rotate the roll to thereby cause the dancer to move from the first position to the second position;   wherein the control circuit calculates a starting speed of the motor based upon the movement of the dancer from the first position to the second position; and   further wherein the control circuit controls the motor at the calculated starting speed to begin supplying the web to the conveyor.   
     
     
         2 . A system according to  claim 1 , wherein the control circuit calculates the diameter of the roll based upon the movement of the dancer from the first position to the second position. 
     
     
         3 . A system according to  claim 2 , wherein the control circuit calculates the diameter of the roll based upon the degree of rotation of the motor required to move the dancer from the first position to the second position. 
     
     
         4 . A system according to  claim 2 , wherein the control circuit calculates the starting speed of the motor based upon the diameter of the roll. 
     
     
         5 . A system according to  claim 1 , wherein the control circuit controls the motor to rotate the roll in a first direction so that the dancer moves from the second position to the first position and then controls the motor to rotate the roll in a second, opposite direction so that the dancer moves from the first position to the second position. 
     
     
         6 . A system according to  claim 5 , wherein the first position is higher than the second position with respect to the conveyor. 
     
     
         7 . A system according to  claim 5 , wherein the sensor comprises a first sensor portion sensing when the dancer is in the first position and a second sensor portion sensing when the dancer is in the second position. 
     
     
         8 . A system according to  claim 1 , wherein the roll has a core and wherein the motor rotates the roll from the core. 
     
     
         9 . A system according to  claim 1 , wherein the conveyor conveys the web in an indexing motion. 
     
     
         10 . A system according to  claim 9 , wherein upon an indexing motion of the conveyor the control circuit controls the speed of the motor to maintain a substantially constant tension in the web during indexing motion of the conveyor. 
     
     
         11 . A system according to  claim 10 , wherein upon an indexing motion of the conveyor, the control circuit monitors a time of movement of the dancer from the first position to the second position and then controls the speed of the motor to maintain a substantially constant time of movement of the dancer. 
     
     
         12 . A method of supplying a web of packaging material to a packaging machine, the method comprising:
 supplying a web of packaging material from a roll to a conveyor for conveying the web from upstream to downstream;   rotating the roll to change tension of the web and cause a dancer to move from a first position to a second position;   sensing the movement of the dancer; and   calculating a starting rotational speed of the roll based upon the movement of the dancer from the first position to the second position; and   rotating the roll at the calculated starting rotational speed to supply the web to the conveyor.   
     
     
         13 . A method for supplying a web of packaging material to a packaging machine, the method comprising:
 supplying a web of packaging material from a roll to a conveyor that conveys the web from upstream to downstream;   providing a dancer located downstream of the roll and upstream of the conveyor, the dancer being movable between first and second positions based upon a change in tension of the web;   controlling the motor to rotate the roll and thereby cause the dancer to move from the first position to the second position;   sensing the movement of the dancer;   calculating a starting speed of the motor based upon the movement of the dancer from the first position to the second position; and   controlling the motor at the calculated starting speed to supply the web to the conveyor.   
     
     
         14 . A method according to  claim 13 , comprising calculating the diameter of the roll at start-up based upon the movement of the dancer from the first position to the second position. 
     
     
         15 . A method according to  claim 14 , comprising calculating the diameter of the roll based upon the degree of rotation of the motor required to move the dancer from the first position to the second position. 
     
     
         16 . A method according to  claim 15 , comprising calculating the starting speed of the motor based upon the diameter of the roll. 
     
     
         17 . A method according to  claim 13 , comprising controlling the motor to rotate the roll in a first direction so that the dancer moves from the second position to the first position and then controlling the motor to rotate the roll in a second, opposite direction so that the dancer moves from the first position to the second position. 
     
     
         18 . A method according to  claim 13 , wherein the roll has a core and comprising rotating the roll from the core. 
     
     
         19 . A method according to  claim 13 , comprising conveying the web in an indexing motion. 
     
     
         20 . A method according to  claim 19 , comprising controlling the speed of the motor to maintain a substantially constant tension in the web during indexing motion of the conveyor. 
     
     
         21 . A method according to  claim 20 , comprising, upon an indexing motion of the conveyor, monitoring a time of movement of the dancer from the first position to the second position and then controlling the speed of the motor to maintain a substantially constant time of movement of the dancer. 
     
     
         22 . A system for supplying a web of packaging material to a packaging machine, the system comprising:
 a motor rotating of a roll of a web of packaging material;   a control circuit controlling the motor; and   a sensor sensing changes in position of a dancer caused by rotation of the roll,   wherein the sensed changes are input to the control circuit;   wherein the control circuit controls the motor to rotate the roll at a starting speed of rotation that is based upon sensed changes in position of the dancer and then further controls the speed of the motor to maintain substantially constant tension in the web of flexible packaging material during indexing motion of the packaging machine.   
     
     
         23 . A system according to  claim 22 , wherein the control circuit calculates the starting speed of rotation for the motor based upon a degree of rotation of the motor required to move the dancer a certain amount. 
     
     
         24 . A system according to  claim 22 , wherein upon an indexing movement of the machine, the control circuit monitors a time of movement of the dancer and further controls the speed of the motor to maintain a substantially constant time of movement of the dancer based upon the time of movement. 
     
     
         25 . A method for supplying a web of packaging material to an indexing-motion packaging machine, the method comprising: rotating of a roll of a web of packaging material; sensing changes in position of a dancer caused by rotation of the roll; rotating the roll at a starting speed of rotation that is based upon sensed changes in position of the dancer and then maintaining substantially constant tension in the web of flexible packaging material during indexing motion of the packaging machine. 
     
     
         26 . A method according to  claim 25 , comprising rotating the roll so as to decrease tension in the web and thereby allow the dancer to move, and calculating the starting speed of rotation of the motor based upon the movement of the dancer.