Electronic Nip Adjustment and Pressure Measurement on Pull Station

Abstract

A pull station has top and bottom continuous loops with the top continuous loop disposed on a frame and movable relative to the bottom continuous loop with a frame actuator connected with the frame. The frame actuator has a sensor for sensing position. A stop, adjustable with a stop actuator and having a load sensor, is operatively engageable with the frame and prevents movement of the top continuous loop toward the bottom continuous loop. A control determines a distance between the top and bottom continuous loops based upon the actuator position sensor; determines a force imparted to webs based on the stop load sensor, the weight of the frame and the top continuous loop, and a force imparted to the top continuous loop by the frame actuator as the webs are conveyed in the pull station; and controls the pull station based upon the distance and/or force measurements.

What is claimed is: 
     
         1 . A control for controlling a pull station of a converting line wherein the pull station comprises a top continuous loop and a bottom continuous loop that are adapted to receive a plurality of webs in a vertically stacked arrangement at an entrance of the pull station and convey the vertically stacked arrangement of webs between the top and bottom continuous loops through a discharge of the pull station, the top continuous loop is disposed on a frame, the frame is adjustable such that the top continuous loop is movable toward and away from the bottom continuous loop, the control comprising:
 a frame actuator adapted and configured to be operatively connected with the frame in a manner to allow the top continuous loop to be moved toward and away from the bottom continuous loop, the frame actuator having a sensor adapted and configured to sense a position of the frame actuator;   a stop adapted and configured to operatively engage the frame and prevent movement of the top continuous loop toward the bottom continuous loop, the stop being adjustable with a stop actuator, the stop having a stop load sensor adapted and configured to sense a load applied against the load sensor when the frame engages the stop; and   a controller including a processor and memory, the controller being configured to (i) determine a distance measurement between the top continuous loop and the bottom continuous loop based upon the actuator position sensor; (ii) determine a force imparted to the plurality of webs based on the stop load sensor, the weight of the frame and the continuous loop, and a force imparted to the top continuous loop by the frame actuator as the plurality of webs are conveyed from the entrance of the pull station to the discharge of the pull station; and (iii) generate signals for controlling the pull station based upon at least one of the distance and force measurements.   
     
     
         2 . The control of  claim 1  wherein the control is configured to store a plurality of data structures in the memory of the controller, wherein the data structures comprise a plurality of data items associated together as the distance measurements between the top continuous loop and the bottom continuous loop as the plurality of webs are conveyed from the entrance of the pull station to the discharge of the pull station, and a characteristic representative of the plurality of webs being conveyed in the pull station. 
     
     
         3 . The control of  claim 1  wherein the control is configured to store a plurality of data structures in the memory of the controller, wherein the data structures comprise a plurality of data items associated together as the force measurements, the distance measurements between the top continuous loop and the bottom continuous loop and a characteristic representative of the plurality of webs being conveyed in the pull station. 
     
     
         4 . The control of  claim 1  further comprising a web speed sensor adapted and configured to sense a speed of the plurality of webs being conveyed in the pull station and generate a web speed signal. 
     
     
         5 . The control of  claim 4  further comprising a speed sensor associated with at least one of the top continuous loop and the bottom continuous loop, the speed sensor being adapted and configured to generate a conveyor speed signal. 
     
     
         6 . The control of  claim 5  wherein the controller is configured to compare the speed of the plurality of webs being conveyed in the pull station with the speed of the at least one of the top continuous loop and bottom continuous loop based upon the web speed signal and the conveyor speed signal; and generate signals for controlling the pull station based upon the comparison. 
     
     
         7 . The control of  claim 6  wherein the controller is configured to send a signal to the frame actuator based on the comparison. 
     
     
         8 . The control of  claim 6  wherein the controller is configured to send a signal to the stop actuator based on the comparison. 
     
     
         9 . The control of  claim 6  wherein the control is configured to store a plurality of data structures in the memory of the controller, wherein the data structures comprise a plurality of data items associated together as the force measurements as the plurality of webs are conveyed from the entrance of the pull station to the discharge of the pull station, the speed of the plurality of webs being conveyed in the pull station, the speed of the at least one of the top continuous loop and bottom continuous loop as the plurality of webs are conveyed from the entrance of the pull station to the discharge of the pull station, the distance measurements between the top continuous loop and the bottom continuous loop as the plurality of webs are conveyed from the entrance of the pull station to the discharge of the pull station, and a characteristic representative of the plurality of webs being conveyed in the pull station. motor. 
     
     
         10 . The control of  claim 1  wherein the frame actuator comprises a pneumatic cylinder. 
     
     
         11 . The control of  claim 1  wherein the stop actuator comprises a linear actuator driven by a motor. 
     
     
         12 . A method of controlling a converting line having a pull station, wherein the pull station comprises a top continuous loop and a bottom continuous loop, the top continuous loop and the bottom continuous loop are adapted to receive a plurality of webs in a vertically stacked arrangement at an entrance of the pull station and convey the stacked arrangement of webs between the top and bottom continuous loops through a discharge of the pull station, the top continuous loop being disposed on a frame, the method comprising:
 providing a frame actuator operatively connected to the frame that supports the top continuous loop of the pull station;   enabling a sensor of the frame actuator to sense a position of the frame actuator;   providing a stop that is configured to engage the frame and prevent movement of the top continuous loop toward the bottom continuous loop;   providing a stop actuator that is configured to adjust the position of the stop;   enabling a stop load sensor of the stop actuator to sense a load applied against the load sensor when the frame engages the stop;   configuring a processor associated with a controller of a control of the converting line to determine a distance measurement between the top continuous loop and the bottom continuous loop based upon the actuator position sensor;   configuring the processor to determine a force imparted to the plurality of webs based on the stop load sensor, the weight of the frame and the top continuous loop, and a force imparted to the top continuous loop by the frame actuator as the plurality of webs are conveyed from the entrance of the pull station to the discharge of the pull station; and   enabling the controller to generate signals for controlling the pull station based upon at least one of the distance and force measurements.   
     
     
         13 . The method of  claim 12  further comprising configuring the controller to store a plurality of data structures in a memory of the controller, wherein the data structures comprise a plurality of data items associated together as the distance measurements between the top continuous loop and the bottom continuous loop as the plurality of webs are conveyed from the entrance of the pull station to the discharge of the pull station, and a characteristic representative of the plurality of webs being conveyed in the pull station. 
     
     
         14 . The method of  claim 12  further comprising configuring the controller to store a plurality of data structures in a memory of the controller, wherein the data structures comprise a plurality of data items associated together as the force measurements as the plurality of webs are conveyed from the entrance of the pull station to the discharge of the pull station, the distance measurements between the top continuous loop and the bottom continuous loop as the plurality of webs are conveyed from the entrance of the pull station to the discharge of the pull station, and a characteristic representative of the plurality of webs being conveyed in the pull station. 
     
     
         15 . The method of  claim 12  further comprising configuring a web speed sensor to sense a speed of the plurality of webs being conveyed in the pull station and generate a web speed signal. 
     
     
         16 . The method of  claim 15  further comprising configuring a speed sensor associated with at least one of the top continuous loop and the bottom continuous loop to sense a speed of the respective continuous loop, and generate a conveyor speed signal. 
     
     
         17 . The method of  claim 16  further comprising configuring the controller to:
 compare the speed of the plurality of webs being conveyed in the pull station with the speed of the at least one of the top continuous loop and bottom continuous loop based upon the web speed signal and the conveyor speed signal; and 
 generate signals for controlling the pull station based upon the comparison. 
 
     
     
         18 . The method of  claim 17  further comprising configuring the controller to send a signal to the frame actuator based on the comparison. 
     
     
         19 . The method of  claim 17  further comprising configuring the controller to send a signal to the stop actuator based on the comparison. 
     
     
         20 . The method of  claim 17  further comprising configuring controller to store a plurality of data structures in a memory of the controller, wherein the data structures comprise a plurality of data items associated together as the force measurements as the plurality of webs are conveyed from the entrance of the pull station to the discharge of the pull station, the speed of the plurality of webs being conveyed in the pull station, the speed of the at least one of the top continuous loop and bottom continuous loop as the plurality of webs are conveyed from the entrance of the pull station to the discharge of the pull station, the distance measurements between the top continuous loop and the bottom continuous loop as the plurality of webs are conveyed from the entrance of the pull station to the discharge of the pull station, and a characteristic representative of the plurality of webs being conveyed in the pull station. 
     
     
         21 . A method of controlling a converting line having a pull station, wherein the pull station comprises a top continuous loop and a bottom continuous loop, the top continuous loop and the bottom continuous loop are adapted to receive a plurality of webs in a vertically stacked arrangement at an entrance of the pull station and convey the vertically stacked arrangement of webs between the top and bottom continuous loops through a discharge of the pull station, the top continuous loop being disposed on a frame, the method comprising:
 providing a frame actuator operatively connected to the frame that supports the top continuous loop of the pull station;   sensing a position of the frame actuator;   adjustably setting a minimum distance between the top continuous loop and the bottom continuous loop;   imparting a force to the top continuous loop with the frame actuator;   sensing a load applied by the frame to the pull station;   determining a distance measurement between the top continuous loop and the bottom continuous loop based upon the position of the frame actuator;   configuring the processor to determine a force imparted to the plurality of webs based on the load applied by the frame actuator to the pull station, the weight of the frame and the top continuous loop, and the force imparted to the top continuous loop by the frame actuator as the plurality of webs are conveyed from the entrance of the pull station to the discharge of the pull station; and   enabling the controller to generate signals for controlling the pull station based upon at least one of the measurement of the distance and the measurement of the force imparted to the plurality of webs.