U.S. patent application number 10/291227 was filed with the patent office on 2004-05-27 for log positioning device and method.
Invention is credited to Gingras, Brian James, Hoo, Daniel, Krautkramer, Robert Eugene, Mertz, Mark Edward.
Application Number | 20040099706 10/291227 |
Document ID | / |
Family ID | 32324322 |
Filed Date | 2004-05-27 |
United States Patent
Application |
20040099706 |
Kind Code |
A1 |
Krautkramer, Robert Eugene ;
et al. |
May 27, 2004 |
Log positioning device and method
Abstract
A method of positioning a log of sheet material includes sensing
the presence of a log in a staging area having a length, a midpoint
at the center of the length, and a boundary point between the
midpoint and an end of the length; sensing the presence or absence
of a portion of the log at the boundary point; and moving the log
along the length of the staging area. When the log is present in
both the staging area and at the boundary point, the log is moved
toward the midpoint. When the log is present in the staging area
and absent from the boundary point, the log is moved toward the
boundary point.
Inventors: |
Krautkramer, Robert Eugene;
(Kaukauna, WI) ; Hoo, Daniel; (Appleton, WI)
; Mertz, Mark Edward; (Greenville, WI) ; Gingras,
Brian James; (Appleton, WI) |
Correspondence
Address: |
GENERAL NUMBER 00757
BRINKS HOFER GILSON & LIONE
P.O. BOX 10395
CHICAGO
IL
60611
US
|
Family ID: |
32324322 |
Appl. No.: |
10/291227 |
Filed: |
November 8, 2002 |
Current U.S.
Class: |
226/1 |
Current CPC
Class: |
B65H 2511/514 20130101;
B65H 19/2284 20130101; B65H 19/12 20130101; B65H 2301/41812
20130101; B65H 2301/36 20130101; B65H 16/02 20130101 |
Class at
Publication: |
226/001 |
International
Class: |
B65H 016/00 |
Claims
1. A method of positioning a log of sheet material, comprising:
sensing the presence of a log in a staging area, the staging area
comprising a length, a midpoint at the center of the length, and a
boundary point between the midpoint and an end of the length;
sensing the presence or absence of a portion of the log at the
boundary point; and positioning the log relative to the boundary
point.
2. The method of claim 1, wherein, when the log is present in both
the staging area and at the boundary point, the positioning
comprises moving the log along the length of the staging area
toward the midpoint until the log is absent from the boundary
point.
3. The method of claim 1, wherein, when the log is present in the
staging area and is absent from the boundary point, the positioning
comprises moving the log along the length of the staging area
toward the boundary point until the log is present at the boundary
point.
4. The method of claim 1, wherein the staging area comprises a
conveyor belt, and the positioning further comprises cycling the
conveyor belt.
5. The method of claim 1, further comprising providing the log in
the staging area prior to sensing the presence of the log in the
staging area.
6. The method of claim 1, further comprising releasing the log from
the staging area after positioning the log relative to the boundary
point.
7. The method of claim 1, wherein the sensing the presence of the
log in the staging area comprises measuring a status of a
switch.
8. The method of claim 1, wherein the sensing the presence of the
log in the staging area comprises measuring a mass of a substance
in the staging area.
9. The method of claim 1, wherein the sensing the presence of the
log in the staging area comprises measuring a signal from an
ultrasonic sensor.
10. The method of claim 1, wherein the sensing the presence of the
log in the staging area comprises measuring a signal from an
optical sensor.
11. The method of claim 1, wherein the sensing the presence or
absence of a portion of the log at the boundary point comprises
measuring a status of a switch.
12. The method of claim 1, wherein the sensing the presence or
absence of a portion of the log at the boundary point comprises
measuring a mass of a substance at the boundary point.
13. The method of claim 1, wherein the sensing the presence or
absence of a portion of the log at the boundary point comprises
measuring a signal from an ultrasonic sensor.
14. The method of claim 1, wherein the sensing the presence or
absence of a portion of the log at the boundary point comprises
measuring a signal from an optical sensor.
15. The method of claim 14, wherein the log comprises a center
portion and an end portion, the center portion comprising a width
edge, and the optical sensor having a focal point which is
positioned past the width edge.
16. The method of claim 15, wherein the focal point is positioned
from about 1 millimeter to about 20 millimeters past the width
edge.
17. The method of claim 15, wherein the focal point is positioned
from about 2 millimeters to about 10 millimeters past the width
edge.
18. The method of claim 15, wherein the optical sensor has a focal
window comprising the focal point.
19. The method of claim 15, wherein the end portion has a uniform
width equal to the width of the center portion.
20. The method of claim 15, wherein the end portion has a
non-uniform width.
21. The method of claim 1, wherein the log comprises a wetting
solution add-on of at least 25%.
22. A method of positioning a plurality of logs of sheet material,
comprising: providing a single log in a staging area, the staging
area comprising a length, a midpoint at the center of the length,
and a boundary point between the midpoint and an end of the length;
sensing the presence or absence of a portion of the log at the
boundary point; positioning the log relative to the boundary point;
releasing the log from the staging area; and repeating the
providing, sensing, positioning and releasing.
23. The method of claim 22, wherein the positioning comprises
moving the log along the length of the staging area toward the
midpoint when the log is present at the boundary point.
24. The method of claim 22, wherein the positioning comprises
moving the log along the length of the staging area toward the
boundary point when the log is absent from the boundary point.
25. The method of claim 22, wherein the providing comprises sensing
the presence of the log in the staging area.
26. The method of claim 22, wherein the length of the staging area
is at least as long as an average length of a plurality of
logs.
27. The method of claim 22, wherein the providing comprises
dispensing the single log from a storage area comprising a
plurality of logs.
28. The method of claim 22, wherein the providing comprises
dispensing the single log from a log forming apparatus.
29. The method of claim 28, wherein the log forming apparatus is an
apparatus for wetting and winding a sheet of material.
30. The method of claim 22, wherein the providing comprises
transporting the single log toward the staging area and depositing
the single log in the staging area.
31. The method of claim 30, wherein the transporting comprises
dispensing the single log onto a conveyor.
32. The method of claim 22, wherein at least 10 logs are positioned
each minute.
33. The method of claim 22, wherein at least 20 logs are positioned
each minute.
34. The method of claim 22, wherein at least 30 logs are positioned
each minute.
35. The method of claim 22, wherein the sensing the presence or
absence of a portion of the log at the boundary point comprises a
member selected from the group consisting of measuring a status of
a switch, measuring a mass of a substance at the boundary point,
measuring a signal from an ultrasonic sensor, and measuring a
signal from an optical sensor.
36. The method of claim 25, wherein the sensing the presence of the
log in the staging area comprises a member selected from the group
consisting of measuring a status of a switch, measuring a mass of a
substance in the staging area, measuring a signal from an
ultrasonic sensor, and measuring a signal from an optical
sensor.
37. A method of positioning a wet log of sheet material,
comprising: sensing the presence of a wet log in a staging area by
measuring a signal from a first optical sensor, the staging area
comprising a length, a midpoint at the center of the length, a
boundary point between the midpoint and an end of the length, and a
conveyor belt; sensing the presence or absence of a portion of the
wet log at the boundary point by measuring a signal from a second
optical sensor; and moving the wet log along the length of the
staging area by cycling the conveyor belt, the moving the wet log
comprising cycling the wet log toward the midpoint until the wet
log is absent from the boundary point, when the wet log is present
in both the staging area and at the boundary point; or cycling the
wet log toward the boundary point until the wet log is present at
the boundary point, when the wet log is present in the staging area
and is absent from the boundary point.
38. An apparatus for positioning a log of sheet material,
comprising: a staging area comprising a length, a midpoint at the
center of the length, and a boundary point between the midpoint and
an end of the length; a first sensor positioned to detect the
presence or absence of the log in the staging area; a second sensor
positioned to detect the presence or absence of a log at the
boundary point; and a conveyor belt positioned to cycle along the
length of the staging area.
39. The apparatus of claim 38, wherein the first sensor comprises
an optical sensor having a field of view along the length of the
staging area.
40. The apparatus of claim 38, wherein the second sensor comprises
an optical sensor having a focal point at the boundary point.
41. The apparatus of claim 40, wherein, when a log comprising a
width edge is in the staging area, the focal point is positioned
past the width edge.
42. The apparatus of claim 38, wherein, when the first sensor
detects the presence of a log in the staging area and the second
sensor detects the presence of a portion of the log at the boundary
point, the conveyor belt cycles to move the log toward the midpoint
until the log is absent from the boundary point.
43. The apparatus of claim 38, wherein, when the first sensor
detects the presence of a log in the staging area and the second
sensor detects the absence of a portion of the log at the boundary
point, the conveyor belt cycles to move the log toward the boundary
point until the log is present at the boundary point.
44. The apparatus of claim 38, wherein the staging area is
connected to a log processing machine.
45. The apparatus of claim 38, wherein the staging area is
connected to a log forming machine.
46. The apparatus of claim 38, further comprising a movable gate
which can release the log from the apparatus.
47. An apparatus for positioning a log of sheet material,
comprising: means for supporting a log; means for detecting the
presence or absence of a log on the supporting means; means for
detecting the presence or absence of a portion of the log at a
boundary point; and means for moving the log toward or away from
the boundary point; wherein, when the log is detected as present
both on the supporting means and at the boundary point, the moving
means moves the log away from the boundary point; and when the log
is detected as present on the supporting means but absent from the
boundary point, the moving means moves the log toward the boundary
point.
Description
BACKGROUND
[0001] Disposable sheet products such as paper towels, toilet
tissue, and wet wipes have many applications. They may be used with
small children and infants when changing diapers, they may be used
for house hold cleaning tasks, they may be used for cleaning hands,
they may be used as a bath tissue, they may be used by a caregiver
to clean a disabled or incontinent adult, or they may be used in
and for a whole host of other applications. Typically, these sheet
products have been provided as a stack of separate sheets or as a
roll of perforated sheets wound on a solid or hollow core.
[0002] Wet wipes have traditionally been made in processes in which
larger webs of wipes are initially made, and then these larger webs
are converted into smaller rolls or sheets that can be placed in a
dispenser. Embodiments of dispensers are described in copending
applications Ser. No. 09/545,995 filed Apr. 10, 2000; Ser. No.
09/565,227 filed May 4, 2000; Ser. Nos. 09/659,307; 09/659,295;
09/660,049; 09/659,311; 09/660,040; 09/659,283; 09/659,284 and
09/659,306, filed Sep. 12, 2000; Ser. No. 09/748,618, filed Dec.
22, 2000; Ser. No. 09/841,323, filed Apr. 24, 2001; Ser. No.
09/844,731, filed Apr. 27, 2001; and Ser. No. 09/849,935, filed May
4, 2001, all of which are commonly assigned to Kimberly-Clark, and
the disclosures of which are incorporated herein by reference.
[0003] Wet wipes can be any wipe, towel, tissue or sheet like
product including natural fibers, synthetic fibers, synthetic
material and combinations thereof, that is wet or moist. Examples
of wet wipes are disclosed in U.S. Pat. Nos. 6,423,804 B1;
6,429,261 B1; 6,444,214 B1; and in copending U.S. patent
applications Ser. Nos. 09/564,449; 09/565,125; 09/564,837;
09/564,531; 09/564,268; 09/564,424; 09/564,780; 09/564,212;
09/565,623 all filed May 4, 2000; and Ser. No. 09/900,698, filed
Jul. 6, 2001. All of these patents and patent applications are
commonly assigned to Kimberly-Clark, and the disclosures of all
these documents are incorporated herein by reference.
[0004] For sheet products that are provided in roll form, it may be
desirable to form the individual rolls by separating the rolls from
a log of rolled sheet material. Logs of rolled sheet materials may
be produced by winding a large amount of sheet material into
individual logs of roughly equal dimensions. The separation of
rolls from a given log of material may then be accomplished, for
example through the use of a saw that sequentially cuts rolls from
the log from one end to the other, or through the use of a
multi-blade saw that divides the log into multiple rolls
simultaneously. Any variability or inconsistency in the log-forming
process may impact the ability to produce consistent, high-quality
individual rolls from the log saw.
[0005] There is thus a need for improved methods of making
individual portions of wipes, particularly for making rolls of wet
wipes. It is desirable that portions of wipes are produced in an
automatic fashion to provide rolls having optimum quality,
consistent dimensions, and uniform ingredients.
BRIEF SUMMARY
[0006] In an embodiment of the invention, there is provided a
method of positioning a log of sheet material, comprising sensing
the presence of a log in a staging area, the staging area
comprising a length, a midpoint at the center of the length, and a
boundary point between the midpoint and an end of the length;
sensing the presence or absence of a portion of the log at the
boundary point; and positioning the log relative to the boundary
point.
[0007] These embodiments may further comprise a method wherein,
when the log is present in both the staging area and at the
boundary point, the positioning comprises moving the log along the
length of the staging area toward the midpoint until the log is
absent from the boundary point. These embodiments may yet further
comprise a method wherein, when the log is present in the staging
area and is absent from the boundary point, the positioning
comprises moving the log along the length of the staging area
toward the boundary point until the log is present at the boundary
point
[0008] In another embodiment of the invention, there is provided a
method of positioning a plurality of logs of sheet material,
comprising providing a single log in a staging area, the staging
area comprising a length, a midpoint at the center of the length,
and a boundary point between the midpoint and an end of the length;
sensing the presence or absence of a portion of the log at the
boundary point; positioning the log relative to the boundary point;
releasing the log from the staging area; and repeating the
providing, sensing, positioning and releasing.
[0009] These embodiments may further comprise a method wherein the
positioning comprises moving the log along the length of the
staging area toward the midpoint when the log is present at the
boundary point. These embodiments may yet further comprise a method
wherein the positioning comprises moving the log along the length
of the staging area toward the boundary point when the log is
absent from the boundary point.
[0010] In another embodiment of the invention, there is provided a
method of positioning a wet log of sheet material, comprising
sensing the presence of a wet log in a staging area by measuring a
signal from a first optical sensor, the staging area comprising a
length, a midpoint at the center of the length, a boundary point
between the midpoint and an end of the length, and a conveyor belt;
sensing the presence or absence of a portion of the wet log at the
boundary point by measuring a signal from a second optical sensor;
and moving the wet log along the length of the staging area by
cycling the conveyor belt, the moving of the wet log comprising
cycling the wet log toward the midpoint until the wet log is absent
from the boundary point, when the wet log is present in both the
staging area and at the boundary point; or cycling the wet log
toward the boundary point until the wet log is present at the
boundary point, when the wet log is present in the staging area and
is absent from the boundary point.
[0011] In another embodiment of the invention, there is provided an
apparatus for positioning a log of sheet material, comprising a
staging area comprising a length, a midpoint at the center of the
length, and a boundary point between the midpoint and an end of the
length; a first sensor positioned to detect the presence or absence
of a log in the staging area; a second sensor positioned to detect
the presence or absence of the log at the boundary point; and a
conveyor belt positioned to cycle along the length of the staging
area.
[0012] In another embodiment of the invention, there is provided an
apparatus for positioning a log of sheet material, comprising means
for supporting a log; means for detecting the presence or absence
of a log on the supporting means; means for detecting the presence
or absence of a portion of the log at a boundary point; and means
for moving the log toward or away from the boundary point; wherein,
when the log is detected as present both on the supporting means
and at the boundary point, the moving means moves the log away from
the boundary point; and when the log is detected as present on the
supporting means but absent from the boundary point, the moving
means moves the log toward the boundary point.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a diagram of a log forming apparatus.
[0014] FIG. 2 is a diagram of a log processing apparatus.
[0015] FIG. 3 is a diagram of a log saw apparatus.
[0016] FIG. 4 is a diagram of a log processing apparatus.
[0017] FIG. 5 is a perspective diagram of a multi-blade log
saw.
[0018] FIG. 6 is a front diagram of a multi-blade log saw.
[0019] FIG. 7 is a diagram of a staging area.
[0020] FIG. 8 is a diagram of a log of material.
[0021] FIG. 9 is a perspective view of an individual roll of wound
sheet material.
[0022] FIG. 10 is a diagram of a log of material and an optical
sensor.
[0023] FIG. 11 is an end view diagram of a log of material and an
optical sensor.
[0024] FIGS. 12A-D are diagrams of a log positioning apparatus.
[0025] FIG. 13 is a diagram of a log positioning apparatus
connected to a log processing apparatus.
DETAILED DESCRIPTION
[0026] A method and apparatus for positioning a log of sheet
material is provided which in general provides for adjusting the
location of the log in a staging area. The positioning may allow
the log to be located in an optimum position relative to an
apparatus for processing or handling the log. The positioning
involves detecting the presence of the log in the staging area,
detecting the presence or absence of a portion of the log in a
particular location of the staging area, and moving the log either
toward or away from that particular location.
[0027] Logs which may be positioned include logs composed of one or
more sheets of material such as paper, cloth, plastic, metal foil,
and mixtures of these materials. A log may contain a single sheet
that has been converted into log form, or it may contain more than
one sheet. For example, a log may contain a single sheet which has
been folded multiple times to provide a log in a form similar to a
rectangular prism. In another example, a log may contain a single
sheet which has been wound to provide a cylindrical log. In yet
another example, a log may contain a plurality of sheets which are
stacked to form a rectangular prism. In this example, the sheets
can be stacked as flat sheets, or they be folded either with or
without any overlap of the ends of the sheets.
[0028] A log of wound sheet material can be provided by a variety
of methods. For example, individual logs may be produced by winding
a sheet material as it is delivered from a sheet forming machine.
In this example, it may be advantageous to use more than one
winding machine, to allow the sheet to be formed continuously
without slowing or stopping the sheet formation as a log is
completed and removed from the winder. In another example,
individual logs may be produced by unwinding a large roll of sheet
material and rewinding the sheet into smaller logs.
[0029] For the production of rolls of wet wipes, the logs may be
maintained in a dry condition for the entire process, including
during the formation of individual rolls, and wet rolls may then be
formed by soaking the individual rolls in a wetting solution. It
may be desirable to provide the log in a moist condition before
dividing it into individual rolls. Logs may be formed in a dry
condition and then soaked in a wetting solution, or a wetting
solution may be applied to the sheet before or during the winding
of the log. It may be desirable to apply a wetting solution to the
sheet prior to winding the sheet into moist logs, so as to provide
uniform and consistent application of moisture and of the
ingredients of the wetting solution. Individual stacks of wet wipes
sheets may also be formed using similar strategies. Individual
stacks may be formed from logs of stacked sheet material, and the
moisture may be applied to the sheet material while it is in sheet
form, in log form, or in individual stacks.
[0030] An example of an apparatus for forming wet logs of sheet
material is illustrated in FIG. 1. A web of sheet material 2 may be
any type of basesheet known to those skilled in the art. Sheet
materials which are useful include fibrous webs, i.e. paper sheets.
For example, a sheet material may be a nonwoven basesheet, such as
a dry-formed basesheet or a wet-laid basesheet, including tissue
and towel basesheets. A sheet material may be an airlaid,
spun-laid, hydroentangled, spun-bond, or melt-blown (for example,
coform) basesheet. A sheet material may be a multi-layer basesheet,
such as a laminate of any combination of these basesheets. A sheet
material may contain a binder, for example a non-dispersible
binder, such as a latex binder or a cross-linkable binder; or a
water-dispersible binder, such as a temperature-sensitve water
dispersible binder or an ion-sensitive water dispersible binder.
Ion-sensitive water-dispersible binders, such as those disclosed in
the above-referenced co-pending patent applications, provide for
water dispersibility of 80% or greater. Water dispersibility is
defined as: 1 minus (the cross-direction wet tensile strength in
water, divided by the original cross-direction wet tensile strength
of the wet wipe), multiplied by 100%.
[0031] The term "nonwoven" means a web having a structure of
individual fibers or threads which are interlaid, but not in a
regular or identifiable manner as in a knitted fabric. Nonwoven
fabrics or webs may be formed from many processes including, for
example, meltblowing processes, spunbonding processes, air laying
processes, and bonded carded web processes.
[0032] The term "coform" refers a process in which at least one
meltblown diehead is arranged near a chute through which other
materials are added to the web while it is forming. Such other
materials may be pulp, superabsorbent particles, natural polymers
(for example, rayon or cotton fibers) and/or synthetic polymers
(for example, polypropylene or polyester) fibers, for example,
where the fibers may be of staple length. Coform processes are
described in U.S. Pat. Nos. 4,818,464 and 4,100,324, which are both
commonly assigned to Kimberly-Clark. Webs produced by the coform
process are generally referred to as coform materials.
[0033] An example of a useful sheet material is Kimberly-Clark
Supreme Care.TM. baby wipes (KIMBERLY-CLARK CORPORATION, Neenah,
Wis.), as described U.S. patent application Publication No. US
2002/0127937 A1, which is commonly assigned to Kimberly-Clark, and
which is incorporated herein by reference. This type of basesheet
contains coform blended with polypropylene fibers and fluff. Other
examples of individual webs include a melt-blown basesheet with a
latex binder; a spun-bond basesheet with a temperature-sensitve
water dispersible binder; and an airlaid basesheet with an
ion-sensitve water dispersible binder. The web may be delivered to
a wetting and winding apparatus 1 as a sheet of material. The web
may be unwound from a roll, or it may be fed to the apparatus
directly from a web making apparatus. The web may be a single
sheet, or the web may have multiple sheets that are combined to
form a multi-ply sheet. Multi-ply sheets may be bonded together,
for example with adhesives, thermal bonding, sonic bonding, or
hydroentanglement. The web may contain perforations, which may
desirably be lines of perforations at regular intervals, and these
perforations may be introduced during the web making process or
during subsequent processing of the sheet. For example, a
perforating apparatus as described in U.S. Pat. No. 5,125,302,
incorporated herein by reference, may be used to perforate the
web.
[0034] In one example, referring to FIG. 1, the web 2 may be
dispensed from a parent roll 4 which can be mounted on a rotating
shaft 6. The unwinding of the roll can be controlled such that the
web is dispensed at a consistent speed and tension even though the
size of the roll is decreasing. The web in sheet form may be
delivered in the direction of arrow 20 to the wetting apparatus 35.
The speed of the web may be at least 60 meters per minute (m/min).
It may be desirable for the speed of the web to be at least 80
m/min; more desirably at least 150 m/min; more desirably still at
least 300 m/min; more desirably still at least 500 m/min; more
desirably still at least 700 m/min; more desirably still at least
1000 m/min. A wetting solution may be applied to the web by wetting
apparatus 35, and the wet web is then delivered to a wet winding
apparatus 41 to provide log 100 of moist, wound sheet material.
Careful handling of the wet web may be desirable, since the
presence of moisture in the web can alter the physical properties
of the material. For example, incorporation of 225% by weight of a
wetting solution can increase the percent elongation at failure
(i.e. "stretch") of a web from 5-10% to 25-40%. In general, the
strength of the web is also decreased upon application of a given
wetting solution.
[0035] It is desirable that the wet winding apparatus can provide
for continuous winding of wet logs. It is also desirable that each
log produced by this apparatus under a given set of conditions has
substantially the same number of sheets (as defined by lines of
perforations) and substantially the same dimensions. Useful wet
winding apparatus may be any winding apparatus known to those
skilled in the art. The wet winding apparatus may, for example,
wind a web around a removable mandrel to produce a coreless
material (U.S. Pat. Nos. 5,387,284; 5,271,515; 5,271,137;
3,856,226). The winding apparatus may, for example, wind a web
around a tubular or cylindrical core (U.S. Pat. Nos. 6,129,304;
5,979,818; 5,368,252; 5,248,106; 5,137,225; 4,487,377). The winding
apparatus may, for example, be a coreless surface winder which can
produce coreless rolls without the use of a mandrel. (U.S. Pat.
Nos. 5,839,680; 5,690,296; 5,603,467; 5,542,622; 5,538,199;
5,402,960; 4,856,725). The above patents are incorporated herein by
reference. Further examples of wet winding apparatus for providing
wet coreless logs are provided in copending applications Ser. Nos.
09/900,516 and 09/900,746, filed Jul. 6, 2001; Ser. No. 09/989,829
filed Nov. 19, 2001; Ser. No. 10/024,999 filed Dec. 18, 2001; and
Ser. No. 10/036,863 filed Dec. 21, 2001; all of which are commonly
assigned to Kimberly-Clark. These copending applications are all
incorporated herein by reference.
[0036] Examples of wetting solutions are given in the above
mentioned U.S. Pat. Nos. 6,423,804 B1; 6,429,261 B1; 6,444,214 B1;
and in copending U.S. patent applications Ser. Nos. 09/564,449;
09/565,125; 09/564,837; 09/564,531; 09/564,268; 09/564,424;
09/564,780; 09/564,212; 09/565,623; and 09/900,698. The amount of
liquid or wetting solution contained within a given wet web can
vary depending on factors including the type of basesheet, the type
of liquid or solution being used, the wetting conditions employed,
the type of container used to store the wet wipes, and the intended
end use of the wet web. Typically, each wet web can contain from
about 25 to about 600 weight percent and desirably from about 200
to about 400 weight percent liquid based on the dry weight of the
web. To determine the liquid add-on, first the weight of a portion
of dry web having specific dimensions is determined. The dry web
corresponds to the basesheet which can be fed to the wetting and
winding apparatus. Then, the amount of liquid by weight equal to a
multiple (e.g. 1, 1.5, 2.5, 3.3, etc., times) where 1=100%,
2.5=250%, etc., of the portion of the dry web, or an increased
amount of liquid measured as a percent add-on based on the weight
of the dry web portion, is added to the web to make it moistened,
and then referred to as a "wet" web. A wet web is defined as a web
which contains a solution add-on between 25% and the maximum add-on
which can be accepted by the web (i.e. saturation). It may be
desirable for the wetting solution add-on to be between about 25%
and 700%; between 50% and 400%; between 100% and 350%; between 150%
and 300%; or between 200% and 250%.
[0037] Due to the nature of any log formation process, especially
winding processes involving moist sheet materials, the final logs
may have some inconsistencies. For example, the amount of basesheet
and/or wetting solution in the final log may vary between logs.
Some of this variation may be the result of inconsistency in the
formation of the initial basesheet, the composition, thickness, and
density of which may vary from the center of the sheet to the
edges. Some of the variation may also result from inconsistency in
the amount of wetting solution applied, inhomogeneity of the
wetting solution, or inconsistency in the absorbancy of the
basesheet. Furthermore, if the wet winding process is not
completely precise, the total sheet area of the log may vary
between logs. The term "total sheet area" refers to the total area
of the sheet or sheets when they are laid flat.
[0038] The shape of the ends of the log may vary between logs. This
type of inconsistency may be due to the sources of variation
mentioned above and/or to other sources of variation. For example,
the stresses imposed on the web during a winding process can
distort the web from its initial dimensions. Wet webs are
especially sensitive to this distortion, and can be stretched out,
or "extruded," during a winding process. Thus, in the case of wet
coreless logs the winding process may form tapered shapes on one or
both ends of the log due to the forces imposed on the sheet during
the winding process. Furthermore, the position of the logs as
collected or delivered from the log forming apparatus may be
inconsistent. For example, the logs may not be in exact alignment
with each other.
[0039] These inconsistencies can cause problems in the subsequent
processing of the logs. For example, if the logs are intended to be
cut into individual stacks or rolls, the inconsistencies can result
in the production of stacks or rolls which do not have the desired
dimensions, causing these non-uniform items to be disposed of as
scrap. In another example, it the logs are intended to be packed
together for storage or shipment, the inconsistencies can result in
packing which is not optimum, causing damage to some of the logs or
causing potential packing space to be wasted. In yet another
example, logs may be processed by marking, for example by printing
or embossing, or by application of additives in a pattern.
Inconsistencies in the shape or placement of the logs can result in
misalignment of the markings and/or additives from their intended
locations.
[0040] The precise and consistent positioning of logs of sheet
material can thus provide for increased consistency of the final
intended product. Once a staging area is properly aligned with the
processing or handling apparatus, each log can be positioned in the
desired location such that the log interacts as intended with the
processing or handling apparatus. A log which is provided in the
staging area, for example after being dispensed from a log forming
machine, can be misaligned and/or may have ends which are not
uniform. Such a log can still be processed into the desired final
product once it has been positioned to the proper location within
the staging area.
[0041] An example of a log processing apparatus which may benefit
from the consistent, automatic positioning of logs of sheet
material is a log saw apparatus. A log saw is an apparatus which
can divide a log of material into smaller units, desirably in a
single cutting step. A log of wound material can be cut into
individual rolls during a single interaction of the log with the
saw. Likewise, a log of stacked sheets can be cut into individual
stacks during a single cutting step. Examples of log saws are
provided in copending applications Ser. Nos. 09/747,594 and
09/748,616, filed Dec. 22, 2000; and Ser. No. 10/003,454, filed
Oct. 31, 2001; all of which are commonly assigned to
Kimberly-Clark. These copending applications are incorporated
herein by reference. It may be desirable for a log saw apparatus to
divide low rigidity substrate logs, such as moistened logs, into
rolls. The use of this type of apparatus may minimize distortion of
the finished product, especially in terms of shape and cut
squareness, and may thus be used to process moistened product.
[0042] In one example of the use of a log saw to process a log of
material, a wound log of wet wipes may be cut into individual rolls
of wet wipes. A log of wound moist sheet material from which rolls
may be cut may have a diameter between 50 mm and 160 mm, desirably
between 55 mm and 130 mm, desirably between 65 mm and 100 mm, and
desirably about 71 mm. When unwound into a sheet, the length of the
resulting sheet may be between 300 inches (8 m) and 1000 inches (25
m), desirably between 400 inches (10 m) and 800 inches (20 m),
desirably about 440 inches (11.2 m). The wound log has a length
along its longitudinal axis between about 2440 mm to 3050 mm,
desirably 2540 mm to 2900 mm, and desirably about 2616 mm. Such a
log of wound moist sheet material may be formed by the wet winding
methods and apparatus described above.
[0043] As shown in FIG. 2, an apparatus 1 may be used to cut an
entire log 100 of substrate into individual rolls 102. In this
example, logs are delivered into a distribution sprocket 11 and are
transported in a direction perpendicular to the longitudinal axis
of the log. The pockets 15 in the distribution sprocket are shaped
to hold logs during the cutting operation without the need to use a
secondary clamping device. A log which is nested into the sprocket
is supported along its entire length and rotated into a cutting
area 80 (FIG. 3) where it is divided into rolls by a cutting
device, such as a multi-blade rotary saw 81 having a common axis
54. The divided log is rotated past the cutting area, and the
individual rolls are secured in the pockets by a roll retention
device 25. The retention device prevents the rolls from leaving the
pockets until the desired roll exit point 56 is reached. Unwinding
and scuffing of the rolls is also prevented by the retention
device. The rolls may be deposited on a diverter 34 which then
delivers the rolls to an index conveyor 33 for further processing.
Since the substrate is secured during the cutting procedure, there
is no need for a spindle or mandrel to be used for roll products.
Thus, coreless rolls of wipes, including wet wipes, can be cut
precisely by this apparatus.
[0044] Referring again to FIG. 2, the logs may be delivered
initially to an infeed conveyor 13. The delivery may be metered if
necessary, such as by a controllably movable gate 26. The conveyor,
which is desirably made of 316L stainless steel, is mounted on a
frame 17. The conveyor may be movably mounted such that it can be
in a lowered position 72 during use or can be in a raised position
74 for maintenance or cleaning. The conveyor may be mounted to the
frame by support arms 73, which are connected to servo motors 71.
These support arms raise or lower the conveyor in response to a
signal from an actuator. The infeed conveyor is equipped with
concave holders 19 that cradle the logs and prevent them from
falling off the conveyor. The holders are preferably shaped as
shown in FIGS. 2 or 4 with planar walls and a curved bottom. This
configuration allows the roll to be dropped into the holder in a
vertical manner, rather than rolling in at an angle. The optional
metering gate 26 can also assist in assuring this vertical
delivery. Holders of different dimensions and configurations may be
employed for different substrates, and the conveyor may be equipped
to support a variety of interchangeable holders.
[0045] When a log reaches the end of conveyor 13, it is transferred
to an apparatus for cutting the log. Referring to FIGS. 2 and 3,
the cutting apparatus of this example includes a distribution
sprocket 11, which rotates the log in the direction of arrow 64
into the cutting area 80. The log is divided in the cutting area,
and the sprocket rotates the divided roll away from the cutting
area to allow for collection of the individual rolls. The sprocket
is mounted on a frame 41 and rotates on a rotating shaft 82. The
sprocket has multiple pockets 15, each of which can hold one log of
material at a time. Referring to FIG. 5, each pocket has a
multiplicity of channels 32 configured so as to allow the blades of
the saw to pass through them in the cutting area. It is desirable
that the channels are narrow enough to provide sufficient support
for the substrate, yet wide enough to allow the blade to pass
through and to allow for thorough cleaning of the sprocket.
[0046] In the example illustrated in FIG. 6, the saw 81 comprises a
plurality of circular blades 16. The number of blades depends on
the number of individual rolls desired and is greater than the
number of rolls. As illustrated, the saw in this example has 26
total blades, 13 each on shafts 42 and 44, form two cutting
assemblies. These two assemblies together can produce 25 rolls of
the desired dimensions from one log. Examples of circular saw
blades include those available from ORBITAL SAW CO, INC. The model
412034 is a nickel plated blade made of D-2 high-chrome tool steel,
with a 24 inch (610 mm) diameter, 3.25 inch (82.6 mm) inner
diameter (ID) bore, and a 0.150 inch (3.81 mm) thickness. The
spacing 46 between the blades is 4 inches (10.2 cm). The blade
diameter of 20-24 inches (508-610 mm) provides for complete cutting
of a log having a diameter of 71 mm while ensuring clearance of the
blade shaft. The blades may operate at a variable speed between
1500 rpm and 1700 rpm, which can be helpful in minimizing
vibrations in the apparatus. The log saw of this example, when
separating each log into 25 rolls, may be operated at a speed
sufficient to produce at least 200 rolls per minute, and may
further produce at least 400 rolls per minute, or 700 rolls per
minute. Higher or lower production speeds may be optimal for logs
of different dimensions and/or containing different types of sheet
material.
[0047] The spacing 46 of the blades relative to each other
determines the size of the individual rolls produced. It follows
that the consistency of this spacing affects the consistency of the
product. Also, the spacing and configuration of the blades relative
to the dimensions of the log affects the amount of waste produced
by cutting the log. If the log is longer than the end-to-end
distance of the array of blades, one or both ends may produce rolls
which are too small to be of commercial value. The ends, referred
to as "trim," are waste material and are typically disposed of. It
is desirable to reduce the size of the trim portions, or to
eliminate them if possible, so as to reduce the overall waste of
the production. To the extent that trim is not eliminated, it may
be necessary to remove the trim from the log saw, such as by way of
a chute. The chute may deliver the trim directly to a container for
discarding or recycling, or the chute may deliver the trim to a
conveyor that removes it from the apparatus.
[0048] The position of a log in a desired location, or within a
desired range of locations, can provide for improved consistency in
the subsequent processing of the log. In the example of the log saw
processing described above, the position of the log can affect the
size of the trim from the ends of the log. The precise positioning
of the log can ensure that the maximum number of individual stacks
or rolls are produced from a log, and it can also ensure that the
trim produced has a size that is within a particular range.
Consistency in the size range of the trim produced can be
beneficial in that it can allow for consistent behavior of the trim
during any trim removal processes. It is desirable that a
relatively small portion of the substrate log is cut from each end
of the log by the outermost saw blades, such that the trim accounts
for less than 10%, less than 5%, or between about 1% and 3% of the
total length of the log.
[0049] The positioning of a log into a desired location may occur
at various points in the production process. For example, the
positioning may occur immediately after the log is formed. In
another example, the positioning may occur immediately prior to the
processing of the log. In either of these cases, a positioning
apparatus may be in direct contact with the log forming machine
and/or the log processing machine, or it may be physically attached
to one or both of the machines. In yet another example, the
positioning may occur at some intermediate point between the
forming of the log and the processing of the log. In the above
example of the log saw processing machine, for example, a
positioning apparatus may be located at the bottom of the infeed
conveyor or at the top of the infeed conveyor. In many cases, it is
desirable to position the log immediately prior to the processing
of the log to minimize the opportunities for misalignment of the
log between the positioning and the processing.
[0050] The positioning method is carried out in a staging area.
Referring to the example of FIG. 7, a staging area 200 can have a
length 202 and a width 204. Comparing FIG. 7 to FIG. 8, it is
desirable that the dimensions of the length and width are at least
as large as the length 224 and width 222 of the log. The length of
the staging area has a midpoint 208 at the center of the length.
The length of the staging area also has two ends 206 at the termini
of the length, and a boundary point 210 between the midpoint and
one of the ends. The boundary point serves as the reference point
for positioning the end of the log, and the midpoint serves as the
reference point for the direction of motion of the log during the
positioning process.
[0051] The method includes detecting the presence of a log in the
staging area, detecting whether a portion of the log is at the
boundary point, and moving the log accordingly. If a log is in the
staging area and is also detected at the boundary point, the log is
automatically moved toward the midpoint of the staging area. The
movement of the log continues until the log is no longer detected
at the boundary point. In contrast, if a log is in the staging area
but is not detected at the boundary point, the log is automatically
moved toward the boundary point and away from the midpoint. In this
case, the movement of the log continues until the log is detected
in the boundary point. Thus, the final position of the log is
substantially the same, whether the log is initially present in or
absent from the boundary point. The precision of the final position
of the log is dependent on how quickly the movement of the log is
stopped when the necessary detection is complete.
[0052] The detection of the log in the staging area can be
accomplished by a variety of methods. For example, the staging area
may have a mechanical switch that is changed from one state to
another state when a log enters the staging area and depresses the
switch. In another example, the staging area may be connected to a
device for measuring the mass of a substance in the area. For
example, the staging area may be connected to an electronic balance
or to a piezoelectric device. In yet another example, the presence
of the log can be detected by an optical sensor or an ultrasonic
sensor. For example, an optical sensor or an ultrasonic sensor may
be configured to detect the presence or absence of a substance
within a given volume of space.
[0053] The detection of the presence or absence of the log in the
boundary point can also be accomplished by applying these same
methods to the boundary point in a localized manner. For example, a
mechanical switch may be positioned at the boundary point. In
another example, a balance or piezoelectric device may be
configured such that it only senses mass changes at the boundary
point and/or in an area past the boundary point and away from the
midpoint. In yet another example, an optical or ultrasonic sensor
may be configured to detect the presence or absence of a substance
at the boundary point.
[0054] It may be desirable for the log to be detected by optical
sensors, since the equipment for this type of sensing is relatively
easy to obtain, to use, and to replace. An optical sensor may
detect an object that passes between a light emitter and a light
receiver (opposed mode), it may detect an object that passes
between a combined emitter/receiver and a reflective target
(retroreflective mode), or it may detect an object that passes
through a beam of emitted light within a given distance of a
combined emitter/receiver (proximity mode). It may be desirable to
use an optical sensor in a proximity mode so as to minimize the
number of components used and to simplify the installation and
alignment of the sensor, especially if sensors may need to be
replaced in the course of long term operation. It may further be
desirable to operate an optical sensor in a convergent proximity
mode, which aligns the focal point of the emitter and receiver
elements of the sensor. An optical sensor operating in a convergent
proximity mode can be used to specifically detect the presence or
absence of objects within a small range of locations.
[0055] A wide variety of optical sensors can be used to detect the
presence of a log or of a portion of a log. Specific examples of
optical sensors include sensors available from BANNER ENGINEERING
CORP., Minneapolis, Min., such as models PD49VP6C200Q and
Q45BB6FQ5. Optical sensors may be configured and used as
recommended by the manufacturer, or they may be modified as needed.
For example, it may be desirable to cover at least a portion of the
optical sensor with a waterproof covering or a splash shield to
minimize the exposure of the sensor to moisture. It may also be
desirable to provide waterproof sealing around any openings,
connections, or fittings. One or more coatings may also be applied
to at least a portion of the sensor, such as moisture-resistant
coatings, thermal insulating coatings, electromagnetic shielding
coatings, and anti-fog coatings.
[0056] The movement of the log within the staging area is
accomplished in response to the initial location of the log as
measured by the two detectors. The log may be pushed along its
length, for example by the force of a shoe that is actuated by a
servo motor or actuated by a pneumatic or hydraulic system. The log
may also be gripped at one or more locations along its length, for
example by a set of clamps, such that the movement of the clamps
provides the movement of the log. These methods may not be
desirable for some log configurations and/or for logs made of
certain substrates. For example, a premoistened log could be
damaged by the frictional forces encountered in pushing the log
along its length, or by the pressure exerted by clamps. Logs having
low rigidity, including premoisted logs, and logs having
non-uniform ends may also be difficult to move precisely through
these methods.
[0057] In order to accommodate as wide a variety of logs as
possible, it may be desirable to move the log within the staging
area with a conveyor. For example, a conveyor may be configured to
cycle in either direction along the length of the staging area. It
is desirable that the length of the conveyor is greater than the
length of the log to be positioned, and further is greater than the
length of the log plus the possible variation in location along the
length of the staging area when the log initially arrives in the
staging area. The conveyor may be flat, or it may be concave to
provide some stabilization to the log during the positioning
process. It may be desirable for the belt on the conveyor to be
made of a corrosion resistant metal, plastic, or cloth. In one
example, the conveyor belt is made of polyurethane that is molded
to have a curved center.
[0058] Logs which can be positioned may have well-defined
dimensions. For example, referring to FIG. 8, the width 222 of the
log 220 may be constant along the entire length 224 of the log. For
circular logs, the width is the same as the diameter. In another
example, the ends of the log may be normal to the axis of the log,
such that the ends are flat and form a well-defined edge. Logs may,
however, be positioned even if they are irregularly shaped. For
example, the width of the log may vary from one end of the log to
the other. In another example, one or both ends of the log may be
irregularly shaped, as illustrated in FIG. 8. In this case, the log
is considered to have a center portion 234 having a uniform log
width, and an end portion 230, over which the width of the log is
reduced from the log width 222 to zero. The bulk of the log between
the end portions is referred to as the central portion in this
case. Irregular end portions may result from a variety of factors,
including irregularities in the shape or composition of the
original basesheet, the log manufacturing process, or the
processing, handling and/or storage of the log prior to its arrival
at the staging area. The dashed lines 235 illustrate where the log
may be divided, for example by a multi-blade log saw, to produce
individual rolls 102. An example of an individual roll is shown in
FIG. 9.
[0059] In a simplistic illustration, an end portion of a log can be
represented as a cone of material at the terminus of a cylinder of
the material. Referring to FIGS. 10 and 11, an optical sensor 240
intended to detect the presence or absence of a log in the boundary
point can be configured to have a focal point 242 that is past the
width edge 228 of the log 220 by a certain distance 250. Thus, the
sensor will detect the log if the optical path intersects the log
at point 242 and at points along the central portion of the log.
This same configuration will detect the absence of the log if the
optical path either fails to intersect the log entirely, or if the
path intersects the log at the end portion at points away from
point 242. Referring to FIG. 11, the focal point 242 may
practically be any point along the line of view of the sensor that
is within the distance of a focal window 243. The focal window is
determined by the actual field of view of the sensor. If an optical
sensor having a focal point is used to detect the presence or
absence of a log at the boundary point, the focal point is the same
as the boundary point.
[0060] Referring still to FIG. 10, an optical sensor 260 intended
to detect the presence or absence of a log in the staging area
generally can be configured with a view along the length of the
staging area. A log 220 in the staging area thus intersects the
line of view 262, allowing the sensor to detect the presence of the
log. The optical sensor 260 may have a narrow field of view along
line 262, or its field of view may be wider than, but centered
generally around, the line of view. The configuration of the sensor
may be modified and optimized to ensure that a non-uniform end of a
log will not produce an inaccurate optical measurement, i.e. a
measurement of an absence of a log when the log is actually present
in the staging area.
[0061] An apparatus for positioning a log of sheet material
according to this method includes a staging area, detectors for
measuring the presence or absence of a log within the staging area
and at the boundary point, and a device for moving the log in
response to the measurements. The apparatus may also contain any
microprocessors, relays, and software necessary to provide
communication between the detectors and the moving device; however,
these components may also be present in the log forming apparatus
and/or the log processing apparatus. It may be desirable for the
forming, positioning and processing of the log to be coordinated by
a single set of controls.
[0062] An example of an apparatus 300 for positioning a log of
sheet material is provided in FIGS. 12A through 12D. The apparatus
includes a conveyor belt 310 operating between a drive pulley 315,
which is operated by servo motor 317, and an idler pulley 320. The
conveyor belt supports the log of sheet material and helps to
define the staging area. The coordinated action of the pulleys
cycles the belt toward one pulley or the other. The pulley and belt
assembly are mounted on brackets 330 and 340. An optical sensor 350
for detecting the presence or absence of a log in the staging area
is shown as mounted on bracket 340, but could also be mounted on
either bracket. Likewise, an optical sensor 360 for detecting the
presence or absence of a log at the boundary point is shown as
mounted on bracket 330, but could be on either bracket. The staging
area is represented in dashed lines as 390. The brackets may be
connected to frame 370 to facilitate connecting the apparatus to
another machine, such as a log forming machine or a log processing
machine.
[0063] In a further example, FIG. 13 illustrates a positioning
apparatus 300 connected to the distribution sprocket 11 of a
multi-blade log saw, by way of frame 370. In this configuration,
the positioning apparatus can receive a log of sheet material from
the infeed conveyor 13. The log is held in place by movable gate
380, which keeps the log in the staging area during the positioning
process and then moves to release the log into the sprocket. The
movement of the gate is coordinated with the timing of both the
infeed conveyor and the sprocket to allow for continuous production
of individual stacks or rolls of wipes. As illustrated, this
example is especially useful for wound logs of sheet material, as
the angled orientation of the apparatus allows the wound log to
roll into and out of the staging area. The rotational motion of the
wound log desirably inhibits any unwinding of the log by providing
for the direction of motion of the tail of the wound sheet to be
opposite the direction of overall motion of the roll itself when
the tail is in contact with the surface.
[0064] A positioning apparatus can be configured to accept logs
formed from a wet winder, as described above, and to move the logs
as necessary into a position that is optimized for the processing
of the logs by a multi-blade log saw, as described above. The
boundary point in this example is a certain distance "L" beyond the
last blade of the saw, away from the midpoint of the staging area,
and can be calculated by the following equation:
L=(Total log length-sum of individual roll lengths)/2;
[0065] The total log length is the minimum length dimension for a
useable log, and corresponds to length 234 in FIG. 8. The sum of
individual roll lengths corresponds to length 244 in FIG. 8. For
logs having a minimum length of 2616 mm and intended to produce 25
rolls of 102 mm lengths, the boundary point of the staging area is
33 mm from the last blade of the log saw (distance "L"), which
corresponds to a distance of 1308 mm from the midpoint of the
staging area. The optical sensor used to detect the log at the
boundary point has a focal point 5 mm beyond the edge of the log
width. It is desirable that the positioning, including both
detections and the necessary movement of the log, occurs in 2
seconds or less, or in 1.5 seconds or less. This speed of operation
allows for a log processing rate of 30 logs per minute, which
translates into a roll production rate of 750 rolls per minute. It
is desirable that at least 10 logs may be processed per minute, and
is more desirable that at least 20 logs may be processed per
minute. The trim produced when using this configuration will have a
width between 32.5 mm and 65 mm.
[0066] It should be noted that the staging area can be mobile or
stationary. It is desirable for the sake of simplicity to use a
stationary staging area to help keep the components of the
apparatus in their proper orientation. In some cases, however, it
may be desirable to use a mobile staging area. For example, the
positioning apparatus may include a conveyor having multiple
staging areas, each associated with a separate group of detection
devices and positioning conveyor. In this way, logs can be
continuously positioned as they are transported to the processing
machine.
[0067] If the positioning apparatus is used with moist logs, it is
desirable that the materials used for the apparatus are resistant
to corrosion. The apparatus and their components may also be coated
with corrosion resistant materials. Examples of corrosion resistant
materials include 316L stainless steel, nickel and its alloys,
tungsten carbide, and poly(tetrafluoroethylene) (TEFLON, DUPONT,
Wilmington, Del.). The components of the apparatus may be
controlled by standard controlling equipment and software. For
example, the apparatus may be controlled and monitored with a
standard programmable logic controller (PLC), which in turn may
interface with a Human Machine Interface (HMI) such as a PANELMATE
HMI (EATON Corp., Columbus, Ohio).
[0068] The positioning of logs of sheet material can thus be
accomplished in a consistent and automatic manner. The consistency
of positioning can allow for consistent processing of the log, and
the automatic nature of the positioning can provide for rapid
throughput of logs, as well as a minimization of operator error.
The positioning of logs can be performed in a relatively small
space, thus providing for straightforward connection of a
positioning apparatus to a log forming machine and/or a log
processing machine. The logs which can be positioned may have a
variety of potentially problematic features, such as high moisture
content, non-uniformity of shape, and low rigidity.
* * * * *