Method and Apparatus for Tail Sealing of Roll Products

Abstract

A circumferential location of a tail end of a log of convolutely wound web material is determined by rotating the log in a stationary position and a diameter of the log is sensed with a sensor at a plurality of times while rotating the log in the stationary position. A plurality of signals corresponding to the diameter of the log at the plurality of times are generated. The signals corresponding to the diameter of the log at the plurality of times a compared. A change in the signals corresponding to the diameter of the log at the plurality of times is detected and associated with the circumferential location of the tail end of the log.

Claims

1. A method of determining a circumferential location of a tail end of a log of convolutely wound web material, the method comprising: a) rotating the log in a stationary position; b) with a sensor, sensing a diameter of the log at a plurality of times while rotating the log in the stationary position, and generating a plurality of signals corresponding to the diameter of the log at the plurality of times; c) comparing the signals corresponding to the diameter of the log at the plurality of times; d) detecting a change in the signals corresponding to the diameter of the log at the plurality of times, and e) associating the change in the signals with the circumferential location of the tail end of the log.

2. The method of claim 1 wherein the step of generating the plurality of signals corresponding to the diameter of the log at the plurality of times comprises generating a smoothed derivative representation of each of the signals.

3. The method of claim 1 further comprising directing an air blast toward the tail end of the log in one of a direction substantially the same as a winding direction of the log and a direction substantially opposite to a winding direction of the log.

4. The method of claim 1 wherein the step of rotating the log in a stationary position comprises rotating the log in a nip between a pair of spaced-apart, rotatable rollers.

5. The method of claim 1 further comprising further rotating the log to orient the tail end of the log to a selected position for further processing based upon the circumferential location of the tail end of the log.

6. A method of determining a circumferential location of a tail end of a log of convolutely wound web material, the method comprising: a) rotating the log in a stationary position; b) with a sensor, sensing a distance from the sensor to the log at a plurality of times while rotating the log in the stationary position, and generating a plurality of signals corresponding to the distance from the sensor to the log at the plurality of times; c) comparing the signals corresponding to the distance from the sensor to the log at the plurality of times; d) detecting a change in the signals corresponding to the distance from the sensor to the log at the plurality of times, and e) associating the change in the signals with the circumferential location of the tail end of the log.

7. The method of claim 6 wherein the step of generating the plurality of signals corresponding to the distance from the sensor to the log at the plurality of times comprises generating a smoothed derivative representation of each of the signals.

8. The method of claim 6 further comprising directing an air blast toward the tail end of the log in one of a direction substantially the same as a winding direction of the log and a direction substantially opposite to a winding direction of the log.

9. The method of claim 6 wherein the step of rotating the log in a stationary position comprises rotating the log in a nip between a pair of spaced-apart, rotatable rollers.

10. The method of claim 6 further comprising further rotating the log to orient the tail end of the log in a selected position for further processing based upon the circumferential location of the tail end of the log.

11. A machine having a pair of rotatable rollers, the rotatable rollers being spaced apart and forming a nip therebetween, the machine being configured to receive a log of convolutely wound web material into the nip between the rotatable rollers and to rotate the log between the rollers with the rollers, the machine further comprising a sensor adapted and configured to measure a distance from the sensor to an outer surface of the log when the log is located in the nip and rotated between the rollers, the machine further comprising a controller, the controller including a processor and memory, the controller being adapted and configured to: (i) process a plurality of signals from the distance sensor at a plurality of times during rotation of the log between the rollers, (ii) detect a change in the plurality of signals from the distance sensor at the plurality of times during rotation of the log between the rollers, (iii) associate the change in the signals with the circumferential location of the tail end of the log, and (iv) store a plurality of data structures in the memory of the controller, wherein the data structures comprise a plurality of data items associated together that are representative of the circumferential location of the tail end of the log.

12. The machine of claim 11 wherein the controller is configured to generate a smoothed derivative representation of each of the signals corresponding to the distance from the sensor to the log at the plurality of times when processing the plurality of signals.

13. The machine of claim 11 further comprising air pressure source, the air pressure source being arranged to direct pressurized air toward a tail end of the log in one of a direction substantially the same as a winding direction of the log and a direction substantially opposite to a winding direction of the log.

14. The machine of claim 11 wherein the controller is configured to rotate the log to orient a tail end of the log to a selected position for further processing based upon the circumferential location of the tail end of the log.

15. A machine having a pair of rotatable rollers, the rotatable rollers being spaced apart and forming a nip therebetween, the machine being configured to receive a log of convolutely wound web material into the nip between the rotatable rollers and to rotate the log between the rollers with the rollers, the machine further comprising a sensor adapted and configured to measure a diameter of the log when the log is located in the nip and rotated between the rollers, the machine further comprising a controller, the controller including a processor and memory, the controller being adapted and configured to: (i) process a plurality of diameter signals at a plurality of times during rotation of the log between the rollers, (ii) detect a change in the plurality of diameter signals at the plurality of times during rotation of the log between the rollers, (iii) associate the change in the signals with the circumferential location of the tail end of the log, and (iv) store a plurality of data structures in the memory of the controller, wherein the data structures comprise a plurality of data items associated together that are representative of the circumferential location of the tail end of the log.

16. The machine of claim 15 wherein the controller is configured to generate a smoothed derivative representation of each of the diameter signals at the plurality of times when processing the plurality of diameter signals.

17. The machine of claim 15 further comprising an air pressure source, the air pressure source being arranged to direct pressurized air toward a tail end of the log in one of a direction substantially the same as a winding direction of the log and a direction substantially opposite to a winding direction of the log.

18. The machine of claim 15 wherein the controller is configured to rotate the log to orient a tail end of the log to a selected position for further processing based upon the circumferential location of the tail end of the log.

Description

DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is a side elevation of an exemplary tail sealing machine.

[0016] FIG. 2 is a schematic diagram of a conventional means of locating a position of an end of a tail or a log of convolutely wound web material.

[0017] FIG. 3 is a schematic diagram of an exemplary system for locating a position of an end of a tail or a log of convolutely wound web material in accordance with the disclosure.

[0018] FIG. 4 is a detail view of an implementation in accordance with the disclosure in the tail sealing machine of FIG. 1.

[0019] FIG. 5 is a graph of detection data representative of the end position of the tail collected from an implementation in accordance with the disclosure.

DETAILED DESCRIPTION

[0020] A common embodiment of a tail sealing machine 10 is illustrated in FIG. 1. An incoming log 12 comes from the rewinder 14, either via a conveyor from the rewinder or down an infeed table 16, and is slowed by a log brush 18. A loader 20 indexes the log 12 into the tail seal machine 10. The preparation rollers 22 detect the tail and prepare it for unwinding and sealing. The unwinding rollers 24 spin the log 12 so the tail is unwound for adhesive application. The adhesive cable 26 applies a line of adhesive to seal the tail to the log 12. The tail pressing roll 28 presses the tail into the adhesive line on the log. The tail position roll 30 controls the position of the tail as it is ejected from the tail seal machine. The outfeed table 32 feeds the log 12 into the next module 34. The preparation rollers 22 as well as other components of the tail sealing machine 10 are supported by a framework which may form lateral sides of the machine.

[0021] The preparation rollers 22 generally position the log 12 so the tail 36 is in the correct place for the next step. Photo eyes detect when the log reaches the center line between the preparation rollers. At that point, the preparation rollers 22 match speed to hold the log stationary within the nip between the preparation rollers 22. As the log 12 is rotated in the nip between the preparation rollers 22, a sensor detects the tail 36.

[0022] FIG. 2 schematically illustrates the current state of the art in locating the end position of the tail 36 of the log 12. In this common embodiment, the log 12 is rotated in a stationary position in the nip between the preparation rollers 22 and an air blast 38 from a high pressure air source 40 opens the tail 36 (i.e. separates the tail from the body of the log) such that the tail covers a sensor 42. Then as the tail 36 is rewound onto the log 12 with the preparation rollers, the point at which the sensor 42 is no longer covered by the tail 36 indicates that the end of the tail has passed by the sensor. Given the diameter of the log 12 and the position of the sensor 42 relative to the location where the log is rotated in the nip between the preparation rollers, which may be determined by the photo eyes, the circumferential position of the end of the tail 36 on the log 12 can be determined. In subsequent processing, the tail 36 is opened a second time so that adhesive can be applied to the log 12 or to the tail 36.

[0023] FIG. 3 schematically illustrates locating the position of the end of the tail 36 of the log 12 in accordance with the disclosure. The circumferential position of the end of the tail 36 on the log 12 is determined utilizing a sensor 44 such as a distance sensor which may be a laser gauging sensor (for example, a high precision laser measuring sensor such as Banner Engineering model LM80KIQP) to look directly at the log body. The distance sensor may generate a signal representative of the distance from the sensor to the log 12 at a plurality of times as the log is rotated in the nip between the preparation rollers 22. The sensor 44 may also in effect sense the diameter of the log 12 at a plurality of times as the log is rotated in the nip between the preparation rollers based on the distance between the sensor 44 and the surface of the log 12. Other sensors for measuring diameter and web caliper may also be used to establish the distance between the sensor and the surface of the log or to capture log diameter.

[0024] The tail seal machine 10 may be provided with a controller 50 in communication with the sensor 44. The controller 50 may be adapted and configured for controlling the tail seal machine 10 or may integrated into a controller for controlling additional machines on the converting line. The controller 50 may include a processor 52 and memory 54. The controller may be adapted and configured to: (i) process a plurality of signals from the sensor 44 at a plurality of times during rotation of the log 12 between the preparation rollers 22, (ii) detect a change in the plurality of signals from the sensor at the plurality of times during rotation of the log between the preparation rollers 22, (iii) associate the change in the signals with the circumferential location of the end of the tail 36 of the log 12, and (iv) store a plurality of data structures 56 in the memory 54 of the controller 50. The data structures 56 may comprise a plurality of data items associated together that are representative of the circumferential location of the end of the tail 36 of the log 12. The sensor 44 may be in communication with the controller 50 and may be configured to sense a distance from the sensor to the log 12 or the diameter of the log 12 at a plurality of times while rotating the log in the stationary position between the preparation rollers 22, and generate a plurality of signals corresponding to the diameter of the log 12 at the plurality of times that are to be transmitted to the controller 50. The controller 50 may be configured to compare the signals corresponding to the distance of the sensor from the log or the diameter of the log 12 at the plurality of times and detect a change in the signals corresponding to the diameter of the log at the plurality of times. The controller 50 may be configured to associate the change in the signals with the circumferential location of the end of the tail 36 of the log 12.

[0025] A rapid change in the signals from the sensor 44 indicates the position of the end of the tail 36 on the outer surface or circumference of the log 12. The signal from the sensor 44 may be processed, for example, by using a Savitzky-Golay filter to generate a smoothed derivative representation of the signal. The controller 50 may associate a change in signal representative of the distance from the sensor to the log or the log diameter with the end position of the tail 36 on the outer surface or circumference of the log. Given that the log diameter is known, and assuming traction (no slip) between the log and machine members (e.g., the preparation rollers), the circumferential location of the tail end can be tracked during subsequent processing. The method may be augmented by using a low volume air 58 from a pressurized air source 60 to help to lift the tail 36 off of the log body. The pressurized air 58 from the air source 60 could be directed in either direction relative to the log's winding direction: directly toward the tail end (in a direction that would tend to open the tail), or indirectly over the tail end (opposite the direction that would tend to open the tail) to leverage the Coanda effect.

[0026] In tail sealing machines 10 such as shown in FIG. 1, the tail location function takes place on a first set of driven rollers (for example, preparation rollers 22) while the function of opening the tail so that adhesive can be applied takes place on a second set of rollers (for example, unwinding rollers 24). In such tail sealing machines 10, the sensor 44 may be mounted on the movable carriage for the upper preparation roller. The moveable carriage allows the upper preparation roller 22 to move relative to the lower preparation roller 22 which remains fixed in position relative to the frame 35, such that the space between the rollers may be changed based on log diameter.

[0027] The log may roll and be received into the preparation rollers 22. The preparation rollers 22 rotate at different speeds to draw the log 12 into the nip between the rollers 22. Photo eyes detect when the log reaches the centerline between the preparation rollers 22, and at that point the rollers 22 match speed to rotate the log 12 in a stationary position such that the end of the tail 36 passes the measuring point of the sensor 44 within one revolution of the log 12. The rapid change in the signal from the sensor 44 may be caused by one or any combination of: the thickness or caliper of the web at the end of the tail 36, the tail having moved away from the log body due to centrifugal reaction to log's rotation, the tail having moved away from the log body caused by a direct or indirect air stream 58.

[0028] FIG. 5 is a chart of data collected from the sensor 44 for several subsequent logs. After the circumferential location of the tail end of the log has been determined, the rolls 22 may continue to rotate (or alternatively, to reverse rotational direction) in order to position the tail end in a desirable orientation for subsequent processing. When the tail end is in a satisfactory orientation, the log may be fed to the next step in the tail sealing process, for example, unwinding rollers 24. In subsequent processing, the tail may be opened so that adhesive can be applied to the log or to the tail.

[0029] In an alternate embodiment in tail sealing machines where the tail end location function takes place on the same set of rolls as the tail opening function, the sensor 44 may be mounted on the movable carriage of the upper roll. In another alternate embodiment of log rotation for tail end detection, the log may be rotated by driven members that engage the inside diameter of each end of the core; these driven members may be similar to center drives in a rewinding machine, for instance, as described in U.S. Pat. No. 11,247,863. In another alternate embodiment of log rotation for tail end detection, the log may be rotated by two rollers located beneath the log, in an arrangement similar to a two-drum rewinder.

[0030] The arrangement described herein provides benefits to the process of determining the circumferential location of the tail end of a roll in terms of operating cost, setup and adjustment time, production speed, and reliability. The arrangement described herein eliminates the energy required to generate a vacuum or an air blast to open the tail of the log in order to locate the tail end, with potentially only low volume air or no compressed air required, providing for a reduced operating cost. The arrangement described herein reduces setup and adjustment time by eliminating the need to change the angle of an air blast for log diameter, or to change air pressure settings for different paper grades and/or roll product configurations. The arrangement described herein increases production speed by eliminating the time consumed in the opening the tail of the log in order to locate the tail end. The arrangement described herein increases reliability by eliminating the process upsets that inevitably occur with even robust tail opening systems.

[0031] Further embodiments can be envisioned by one of ordinary skill in the art after reading this disclosure. In other embodiments, combinations or sub-combinations of the above-disclosed invention can be advantageously made. The example arrangements of components are shown for purposes of illustration and it should be understood that combinations, additions, re-arrangements, and the like are contemplated in alternative embodiments of the present invention. Thus, various modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the claims and that the invention is intended to cover all modifications and equivalents within the scope of the following claims.