U.S. patent application number 10/755335 was filed with the patent office on 2005-03-17 for method and apparatus for guiding side edges of continuously running web.
Invention is credited to Nomura, Hironori, Shimakawa, Taiji, Yamamoto, Hiroki.
Application Number | 20050056678 10/755335 |
Document ID | / |
Family ID | 32709037 |
Filed Date | 2005-03-17 |
United States Patent
Application |
20050056678 |
Kind Code |
A1 |
Nomura, Hironori ; et
al. |
March 17, 2005 |
Method and apparatus for guiding side edges of continuously running
web
Abstract
The present invention is to provide a method and an apparatus
facilitating side edges of a web continuously running in a machine
direction to be quickly corrected when these side edges are
detected to be out of coincidence with a positions in a cross
direction orthogonal to the machine direction. Roll means rotating
about a shaft extending in a direction defined between a machine
direction and a cross direction are put in contact with side edge
of a web continuously running in the machine direction. The shaft
is mounted on an arm adapted to rotate back-and-forth so that the
shaft can swing in- and outward in the cross direction. Downstream
of the roll means, the side edge is position-detected and the arm
is made swing by a desired angle determined on the basis of a
difference between the actual position and a desired position.
Inventors: |
Nomura, Hironori;
(Kagawa-ken, JP) ; Shimakawa, Taiji; (Kagawa-ken,
JP) ; Yamamoto, Hiroki; (Kagawa-ken, JP) |
Correspondence
Address: |
LOWE HAUPTMAN GILMAN AND BERNER, LLP
1700 DIAGONAL ROAD
SUITE 300 /310
ALEXANDRIA
VA
22314
US
|
Family ID: |
32709037 |
Appl. No.: |
10/755335 |
Filed: |
January 13, 2004 |
Current U.S.
Class: |
226/21 |
Current CPC
Class: |
A61F 13/15764 20130101;
B65H 23/038 20130101; A61F 13/15772 20130101; B65H 23/0251
20130101 |
Class at
Publication: |
226/021 |
International
Class: |
B65H 023/038 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 14, 2003 |
JP |
2003-005961 |
Claims
What is claimed is:
1. A method for guiding a web continuously running in a machine
direction and having a pair of side edges opposed to each other in
a cross direction orthogonal to said machine direction so that at
least one of said side edges is guided to a predetermined position
in said cross direction by putting roll means rotating about a
shaft extending in a direction defined between said machine
direction and said cross direction in contact with a vicinity of at
least one of said side edges, said method comprising the steps of:
mounting an arm having a proximal end and a distal end opposed to
said proximal end at said proximal end on a pivot pin adapted to
rotate back-and-forth so that said arm swings around said pivot pin
in- and outward as viewed in said cross direction; supporting said
shaft of said roll means by said distal end of said arm so that
said roll means also swing about said pivot pin in- and outward;
detecting, at downstream of said roll means, a position of said one
side edge after this side edge has been guided; and driving said
arm by driving means adapted to operate on the basis of a
difference between said position detected in this manner and said
desired position so that said arm swings in- or outward in said
cross direction by a predetermined angle.
2. The method according to claim 1, wherein said driving means
comprises an extensible/retractable arm operatively associated with
a servomotor adapted to rotate in a direction and at a rotational
frequency depending on the difference between said detected
position and said desired position and thereby to extend or retract
said extensible/retractable arm so that said side edge is guided to
said desired position.
3. The method according to claim 1, wherein said roll means is put
in contact with at least one side of said web.
4. The method according to claim 1, wherein said roll means
comprises a pair of rolls extending in parallel to each other and
adapted to nip at least said one side edge and the vicinity
thereof.
5. The method according to claim 1, wherein said roll means are
provided in vicinities of a pair of said side edges to guide these
side edges to respective said desired positions.
6. An apparatus for guiding a web continuously running in a machine
direction and having a pair of side edges opposed to each other in
a cross direction orthogonal to said machine direction so that at
least one of said side edges is guided to a predetermined position
in said cross direction by putting roll means rotating about a
shaft extending in a direction defined between said machine
direction and said cross direction in contact with a vicinity of at
least one of said side edges, said apparatus further comprising:
said shaft of said roll means being supported on a distal end of an
arm which has a proximal end and said distal end opposed to said
proximal end; said proximal end of said arm being mounted on a
pivot pin adapted to rotate back-and-forth so that said arm swings
about said pivot pin in- and outward as viewed in said cross
direction; detector means being provided downstream of said roll
means in said machine direction to detect a position of said one
side edge immediately after said one side edge has been guided; and
said arm being operatively associated with driving means adapted to
operate on the basis of a difference between said position detected
by said detector means and said desired position so that said arm
swing in- or outward in said cross direction by a desired
angle.
7. The apparatus according to claim 6, wherein said driving means
comprises an extensible/retractable arm operatively associated with
a servomotor.
8. The apparatus according to claim 6, wherein said roll means is
put in contact with at least one side of said web.
9. The apparatus according to claim 6, wherein said roll means
comprises a pair of rolls extending parallel to each other and
adapted to nip at least said one side edge and the vicinity
thereof.
10. The apparatus according to claim 6, wherein said roll means are
provided in vicinities of a pair of said side edges to guide these
side edges to respective said predetermined positions.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a method and an apparatus
allowing, in the course of continuously feeding a flexible web of
nonwoven fabric, plastic film, paper or the like in a machine
direction, side-edges of such a web to be guided to desired
positions in a cross direction orthogonal to the machine
direction.
[0002] It is well known in prior art references 1, 2, 3 listed
below, in the course of continuously feeding a flexible web of
nonwoven fabric, plastic film, paper or the like in a machine
direction, to put guide roll means rotating about respective shafts
each obliquely extending at a desired angle with respect to the
machine direction in contact with the vicinities of side edges of
such a web and thereby to move the side edges so that the web may
be broadened. It is also well known that the web can be unwrinkled
by guiding the side edges of the web. Prior art reference discloses
a method for guiding the side edges of the web continuously fed to
desired positions by operatively associating such guide roll means
with detector means adapted to detect actual positions of the
web.
[0003] Prior art reference 1: GB Patent Publication No.
1,373,682
[0004] Prior art reference 2: U.S. Pat. Publication No.
4,920,622
[0005] Prior art reference 3: U.S. Pat. Publication No.
2,718,046
[0006] Of the apparatuses disclosed in Prior art references 1
through 3, one apparatus has the guide roll means fixed at a
predetermined angle relative to the machine direction, another
apparatus is adapted to vary a contact pressure between the guide
roll means and the web, and further another apparatus has the guide
roll means in the form of paired nip rolls adapted to vary a nip
pressure against the web. When it is intended to guide the side
edges of the web detected to be out of. coincidence with desired
positions to these desired positions by appropriately varying the
contact pressure or the nip pressure, it is relatively easy to
shift the side edges outward in the axial direction of the guide
roll means, i.e., outward in the cross direction corresponding to
the transverse direction of the web. However, it is difficult to
shift the side edges in the directions other than the outward
direction, for example, inward in the cross direction. For these
apparatuses disclosed in Prior art references 1, 2, 3 respectively
provided with such guide roll means, it has been impossible to
guide the side edges of the web little by little with a high
accuracy or to position-shift the side edges of the web quickly. In
addition, the web of nonwoven fabric, plastic film or the like
which has been tightly wounded around a roll core generally
exhibits a subtle variation in a width of the web as the web is
released and fed in the machine direction directly from such
tightly wound state. Such subtle variation of the width of the web
may occur also due to a pulling force exerted on the web in the
machine direction. Synergistic effect of these variation
destabilizes the width of the web and therefore destabilizes
positions of the side edges of the web in the cross direction. In
consequence, it is difficult to continuously make articles each
having a high dimensional accuracy by utilizing the side edges of
the web.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to provide a method
and an apparatus facilitating the side edges of the web
continuously running in the machine direction to be quickly guided
to desired positions in the cross direction when these side edges
are detected to be out of coincidence with the desired positions in
the cross direction.
[0008] According to a first aspect of the present invention, there
is provided a method for guiding a web continuously running in a
machine direction and having a pair of side edges opposed to each
other in a cross direction orthogonal to the machine direction so
that at least one of the side edges is guided to a predetermined
position in the cross direction by putting roll means rotating
about a shaft extending in a direction defined between the machine
direction and the cross direction in contact with a vicinity of at
least one of the side edges.
[0009] The first aspect of the present invention comprises the
steps of: mounting an arm having a proximal end and a distal end
opposed to the proximal end at the proximal end on a pivot pin
adapted to rotate back-and-forth so that the arm swings about the
pivot pin in- and outward as viewed in the cross direction,
supporting the shaft of the roll means by the distal end of the arm
so that the roll means also swing about the pivot pin in- and
outward, detecting, at downstream of the roll means, a position of
the one side edge immediately after this side edge has been guided,
and driving the arm by driving means adapted to operate on the
basis of a difference between the position detected in this manner
and the predetermined position so that the arm swings in- or
outward in the cross direction by a predetermined angle.
[0010] The present invention on the first aspect may be implemented
also in manners as follow:
[0011] The driving means comprises an extensible/retractable arm
operatively associated with a servomotor adapted to rotate in a
direction and at a rotational frequency depending on the difference
between the detected position and the predetermined position and
thereby to extend or retract the extensible/retractable arm so that
the side edge is guided to the predetermined position.
[0012] The roll means is put in contact with at least one side of
the web.
[0013] The roll means comprises a pair of rolls extending in
parallel to each other and adapted to nip at least one side edge
and a vicinity thereof.
[0014] The roll means are provided in vicinities of a pair of the
side edges to guide these side edges to the respective
predetermined positions.
[0015] According to a second aspect of the present invention, there
is provided an apparatus for guiding a web continuously running in
a machine direction and having a pair of side edges opposed to each
other in a cross direction orthogonal to the machine direction so
that at least one of the side edges is guided to a predetermined
position in the cross direction by putting roll means rotating
about a shaft extending in a direction defined between the machine
direction and the cross direction in contact with a vicinity of at
least one of the side edges.
[0016] The second aspect of the present invention further
comprising the following features: The shaft of the roll means is
supported on a distal end of an arm having a proximal end and the
distal end opposed to the proximal end; the proximal end of the arm
is mounted on a pivot pin adapted to rotate back-and-forth so that
the arm swings about the pivot pin in- and outward as viewed in the
cross direction; detector means is provided downstream of the roll
means in the machine direction to detect a position of the one side
edge after this side edge has been guided; and the arm is
operatively associated with driving means adapted to operate on the
basis of a difference between the position detected by the detector
means and the predetermined position so that the arm swings in- or
outward in the cross direction by a predetermined angle.
[0017] The second aspect of the present invention may be
implemented also in manners as follow:
[0018] The driving means comprises an extensible/retractable arm
operatively associated with a servomotor.
[0019] The roll means is put in contact with at least one side of
the web.
[0020] The roll means comprises a pair of rolls extending in
parallel to each other and adapted to nip at least one side edge
and a vicinity thereof.
[0021] The roll means are provided in vicinities of a pair of the
side edges to guide these side edges to the respective desired
positions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a plan view showing a partially cutaway disposable
diaper;
[0023] FIG. 2 is a diagram illustrating a part of process for
making the disposable diaper;
[0024] FIG. 3 is a diagram illustrating a part of FIG. 2 in an
enlarged scale;
[0025] FIG. 4 is a sectional view taken along the line IV-IV in
FIG. 3;
[0026] FIG. 5 is a sectional view taken along the line V-V in FIG.
3;
[0027] FIG. 6 is a diagram illustrating a part of FIG. 5 in an
enlarged scale;
[0028] FIG. 7 is a sectional view taken along the line VII-VII in
FIG. 5;
[0029] FIG. 8 is a sectional view taken along the line VIII-VIII in
FIG. 5;
[0030] FIG. 9 is a view similar to FIG. 3, illustrating one
preferred embodiment of the present invention; and
[0031] FIG. 10 is a view similar to FIG. 4, illustrating this
embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] Details of a method and an apparatus according to the
present invention will be more fully understood from the
description given hereunder with reference to the accompanying
drawings.
[0033] A disposable diaper 1 shown by FIG. 1 in a plan view as
partially broken away is a product obtained by a method and an
apparatus according to the present invention. This diaper 1
comprises a liquid-pervious topsheet 2, a liquid-impervious
backsheet 3 and a liquid-absorbent core 4 interposed between these
sheets 2, 3. The diaper 1 has a in- and outward direction
(longitudinal direction as viewed in FIG. 1) and a
waist-surrounding direction (transverse direction as viewed in FIG.
1). The diaper 1 is peripherally contoured by a pair of side edges
11 extending parallel to each other in the in- and outward
direction and a pair of ends extending parallel to each other in
the waist-surrounding direction. As viewed in the in- and and
outward direction, the diaper 1 is composed of a front waist region
6, a rear waist region 7 and a crotch region 8 extending between
these waist regions 6, 7 wherein tape fasteners 13 laterally extend
from the side edges 11 in the rear waist region 7. The topsheet 2
may be formed from liquid-pervious materials such as nonwoven
fabrics or aperture plastic films, the backsheet 3 may be formed
from liquid-impervious materials selected from plastic films,
nonwoven fabrics and plastic film/nonwoven fabric laminates. The
diaper 1 further comprises elastic members attached in a stretched
state thereto so as to extend along the side edges 11 and the ends
12.
[0034] FIG. 2 is a plan view illustrating a part of process for
continuously making the diaper 1, FIG. 3 is a scale-enlarged plan
view illustrating a part of FIG. 2 and FIG. 4 is a partially
cutaway sectional view taken along the line IV-IV in FIG. 3. As
viewed in FIG. 2, a first continuous web 21 destined to form the
backsheet 3 of the diaper 1 is continuously fed in a machine
direction MD downward from above. The continuous web 21 is guided
through an edge controller 40 to control a width of the web 21 to a
desired dimension and then loaded thereon with the cores 4 which
are arranged intermittently in the machine direction MD. Then,
second continuous web 22 destined to form the topsheet 2 of the
diaper 1 is continuously fed so as to cover the cores 4 whereupon
the first continuous web 21 and the second continuous web 22 are
joined together around the respective cores 4 by means of adhesives
or a suitable welding technique to form a continuous assembly 26.
The continuous assembly 26 is cut along lines each extending in a
cross direction CD orthogonal to the machine direction MD between
each pair of the adjacent cores 4 followed by attaching a pair of
the tape fasteners 13 to the first web 21 of each unit assembly cut
from the continuous assembly 26. In this manner, the individual
diapers 1 as shown by FIG. 1 are obtained. In FIGS. 2, 3 and 4, the
first and second continuous webs 21, 22 as well as the cores 4 are
indicated by imaginary lines and, in FIG. 2, the diaper 1 is
illustrated as partially broken away.
[0035] The first continuous web 21 has first and second side edges
31, 32 opposed to each other in the cross direction CD and
extending parallel to each other in the machine direction MD. The
edge controller 40 functions as a controlling means for the first
continuous web 21. Specifically, the edge controller 40 guides at
least one of vicinities of the first side edge 31 and the second
side edge 32 to a position predetermined position in the cross
direction CD and thereby controls the width of the first continuous
web 21 to a desired dimension. The edge controller 40 exemplarily
illustrated comprises a first edge controller 41 operatively
associated with the first side edge 31 and a second edge controller
42 operatively associated with the second side edge 32. These two
edge controllers 41, 42 are substantially identical to each other,
so the first edge controller 41 will be primarily described with
reference to FIGS. 2 through 4. The term used herein "vicinities of
the respective side edges" should be understood to include the
respective side edges and the vicinities thereof.
[0036] The first edge controller 41 includes a movable plate 47
adapted to be movable in the cross direction CD relative to a base
plate 46 extending across the first continuous web 21. The movable
plate 47 is provided with an actuator 48 and a swing arm 49. A
support bar 51 mounted on the base plate 46 downstream in the
machine direction MD and extending in the cross direction CD is
provided with a photoelectric sensor unit 52. The photoelectric
sensor unit 52 electrically connected with the actuator 48
functions to detect an actual position of the first side edge of
the first continuous web 21 and to compare this actual position to
a predetermined position on which the first side edge 31 should
fall. Based on such comparison, the photoelectric sensor unit 52
calculates a direction and a distance in and by which the first
side edge 31 should be shifted to the predetermined position. The
actuator 48 comprising a servomotor 53, a extensible/retractable
arm 54 and a ball screw joint (not shown) interposed between these
motor 53 and the arm 54 rotates the motor 53 in accordance with the
direction and the distance calculated by the photoelectric sensor
unit 52 and thereby and thereby extends or retracts the arm 54
depending on a result of calculation. A distal end of the
extensible/retractable arm 54 is rotatably connected to a distal
end 59 of the swing arm 49 by means of a pivot pin 56. A proximal
end 57 of the swing arm 49 opposite to the distal end 59 is mounted
on the movable plate 47 by means of a pivot pin 58 around which the
swing arm 49 can swing in- and outward in the cross direction CD.
The distal end 59 of the swing arm 49 is provided with a roll unit
63 specifically comprising first and second nip rolls 61, 62
arranged vertically as viewed in FIG. 4. The roll unit 63 comprises
a bracket 64 fixed to the swing arm 49, a supporter 67 extending
from this bracket 64 and supports a first rotary shaft 66 at its
opposite ends and a second rotary shaft 68 extending from the
bracket 64 and supports the second nip roll 62 at its opposite
ends. The first nip roll 61 and the second nip roll 62 are free to
rotate about the first rotary shaft 66 and the second rotary shaft
68, respectively, both in the machine direction MD and in the
direction opposite to the machine direction MD.
[0037] The photoelectric sensor unit 52 shown in FIG. 4 has an
upper arm 82 provided with a light emitter 82a extending in the
cross section CD and a lower arm 83 provided with a light receiver
83a extending in the cross section CD. From the light receiver 83a,
an output cord 83b extends toward the actuator 48. The unit 52 is
adapted to detect the first side edge 31 of the first continuous
web 21 indicated by imaginary line. In FIGS. 2 and 3, a
photoelectric sensor unit 152 in the second edge controller 42 of
the edge controller 40 is shown as mounted on a support bar 151,
but this photoelectric sensor unit 152 is not shown in FIG. 4.
[0038] With the edge controller 40 constructed in this manner, an
actual position of the first side edge 31 detected by the
photoelectric sensor unit 52 located downstream of the first edge
controller 41 is compared with the predetermined position on which
the first side edge 31 should fall. Operation of the actuator 48
based on such comparison causes the swing arm 49 connected with the
extensible/retractable arm 54 to swing about the pivot pin 58 by a
desired angle inward or outward in the cross direction CD, i.e.,
inward or outward in the transverse direction of the first
continuous web 21. The roll unit 63 mounted on the distal end 59 of
the swing arm 49 also swings as the swing arm 49 swings in this
manner.
[0039] In the roll unit 63, the first rotary shaft 66 of the first
nip roll 61 and the second rotary shaft 68 of the second nip roll
62 extend between the machine direction MD and the cross direction
CD and normally extend so as to intersect the machine direction MD.
In FIGS. 2 and 3, the first nip roll 61 extending in the transverse
direction of the first continuous web 21 after having slightly
swung from the cross direction CD toward the machine direction MD
is indicated by solid line while the first nip roll 61 having
significantly swung outward in the transverse direction of the
first continuous web 21 is indicated by imaginary line. The second
nip roll 62 underlies the first nip roll 61 and therefore can not
be seen in FIGS. 2 and 3. The roll unit 63 functions to move the
first side edge 31 and its vicinity of the first continuous web 21
nipped between the first and second nip rolls 61, 62 outward in the
transverse direction as the swing arm 49 swings outward in the
transverse direction of the first continuous web 21. In this
course, the first and second nip rolls 61, 62 substantially falling
on the cross direction as viewed in FIGS. 2 and 3 swing so that
their respective inner ends 61a, 62a put aside inward in the
transverse direction of the first continuous web 21 move to
downstream of their respective outer ends 61b, 62b put aside
outward in the transverse direction of the first continuous web 21
as viewed in the machine direction MD. In other words, swing of the
arm 49 outward in the transverse direction of the first continuous
web 21 causes the rotary shafts 66, 68 of the first and second nip
rolls 61, 62 to swing so that a tilt angle a of these rotary shafts
66, 68 relative to the machine direction MD gradually decreases.
The movable plate 47 on which the first edge controller 41 is
mounted is fixed at a position in the cross direction CD adjusted
so that the first and second nip rolls 61, 62 can repetitively
swing at any given time in the vicinity of the first side edge 31
of the first continuous web 21.
[0040] Similar to the first edge controller 41, the second edge
controller 42 constituting the edge controller 40 comprises a
movable plate 147 mounted on the base plate 46 so that its position
in the cross direction CD may be adjusted, an actuator 148, a swing
arm 149, a pivot pin 148, a roll unit 163 and a photoelectric
sensor unit 152. Of these reference numerals, those added with 100
designate the components constituting the second edge controller
42. In the second edge controller 42, the roll unit 163 is placed
in a mirror symmetric relationship with the roll unit 63 in the
first edge controller 41 and the other components such as the
actuator 148 and the swing arm 149 are mounted on the movable plate
147 in an appropriate layout allowing such mirror symmetric
relationship between these roll units 63. 163. The arm 149 adapted
to in- and outward swing on the basis of data supplied from the
photoelectric sensor unit 152 adapted to detect an actual position
of the second side edge 32. In response to swing of this arm 149
outward in the transverse direction of the first continuous web 21,
the first and second nip rolls 161, 162 of the roll unit 163 swing
in the same manner as in the case of the first and second nip rolls
61, 62 of the roll unit 63 so that so that their respective inner
ends 161a, 162a put aside inward in the transverse direction of the
first continuous web 21 move to downstream of their respective
outer ends 161b, 162b put aside outward in the transverse direction
of the first continuous web 21 as viewed in the machine direction
MD with a tilt angle .beta. of these nip rolls 161b, 162b relative
to the machine direction MD gradually decreasing. The first and
second edge controllers 41, 42 operate independently of each
other.
[0041] FIG. 5 is a sectional view taken along the line V-V in FIG.
3, showing profiles of the second edge controller 42 and the
photoelectric sensor unit 152. In FIG. 5, the roll unit 163 is
oriented in coincidence with the cross direction CD. In the second
edge controller 42, the pivot pin 158 of the swing arm 149 lies
upstream in the machine direction MD and rotatably mounted on a
pedestal 171 which is, in turn, fixed to the movable plate 147. The
swing arm 149 extends from upstream toward downstream in the
machine direction MD and provided on its distal end 159 with the
roll unit 163 fixed thereto. In the vicinity of the distal end 159,
the extensible/retractable arm 154 is mounted on the swing arm 149
by means of the pivot pin 156 so that the arm 154 can rotate around
the pivot pin 156. The roll unit 163 comprises the first nip roll
161 and the second nip roll 162. After having been nipped by these
two rolls 161, 162, the first continuous web 21 horizontally runs
through the photoelectric sensor unit 152 and further runs toward
downstream in the machine direction MD as indicated by imaginary
line.
[0042] FIG. 6 is a scale-enlarged view showing the roll unit 163
FIG. 5, FIG. 7 is a sectional view taken along the line VII-VII,
and FIG. 8 is a sectional view taken along the line VIII-VIII in
FIG. 5, respectively. The roll unit 163 has a bracket 164 fixed to
the swing arm 149. The bracket 164 has inner and outer surfaces
173, 174 placed aside inward and outward, respectively as viewed in
the transverse direction of the first continuous web 21. From the
inner surface 173, a cylindrical arm 176 horizontally extends and
supports the first nip roll 161 and this arm 176 is provided on its
inner end 176a with an inverted. square U-shaped supporter 167
mounted thereon by means of coupling means 177 as will be seen in
FIG. 8. The supporter 167 rotatably supports opposite ends of a
first rotary shaft 166 of the first nip roll 161. Also from the
inner surface 173, a second rotary shaft 168 supporting the second
nip roll 162 horizontally extends and rotatably mounted on the
bracket 164. From the outer surface 174 of the bracket 164, an
outer end 176b of the cylindrical arm 176 extends and a plate
member 179 is fixed around this outer end 176b. One end of a coil
spring 181 operatively associated with the nip roll unit is
anchored on the plate member 179 and the opposite end of the coil
spring 181 is anchored on an angular plate 172a of the bracket
164.
[0043] In the roll unit 163 constructed in this manner, the bracket
164 swings in- and outward integrally with the swing arm 149 around
the pivot pin 158. The first nip roll 161 is rotatable about the
first rotary shaft 166 toward down- and upstream in the machine
direction MD. The cylindrical arm 176 is supported by the bracket
164 and rotatable in two directions indicated by a double-headed
arrow A (See FIG. 6). While the first nip roll 161 can be brought
in contact with or spaced from the second nip roll 162 as the
cylindrical arm 176 rotates, the first nip roll 161 is normally
biased by the spring 181 to come in contact with the second nip
roll 162. The first nip roll 161 is also rotatable around the
coupling means 177 in the direction indicated by the double-headed
arrow B (See FIG. 8). The second nip roll 162 is supported by the
bracket 164 by means of the second rotary shaft 168 and rotatable
toward downstream as well as toward upstream in the machine
direction MD. Swing of the first nip roll 161 in the directions
indicated by the double-headed arrows A and B causes the vicinity
of the second side edge 32 of the first continuous web 21 nipped
between the first nip roll 161 and the second nip roll 162 to be
held in close contact with these two rolls 161, 162 and thereby to
follow in- and outward swinging of these two rolls 161, 162.
[0044] The first and second nip rolls 61, 62 of the roll unit 63
and the first and second nip rolls 161, 162 of the roll unit 163
tilt at angles of .alpha. and .beta. relative to the machine
direction MD when the roll units 63, 163 respectively nip the
vicinity of the first side edge 31 and the vicinity of the second
side edge 32 of the first continuous web 21. Consequently, a force
tending to broaden a transverse dimension of the first continuous
web 21 is exerted on the extent of this web 21 between the first
and second side edges 31, 32 thereof. If the first continuous web
21 guided through the edge controller 40 has wrinkles, the force
tending to broaden the web 21 functions to unwrinkled the web 21.
When such effect is not required, the roll units 63, 163 may be
previously swung in the respective directions in which the tilt
angles .alpha. and .beta. are appropriately decreased. The
directions in which the pair of the first and second nip rolls 61,
62 and the pair of the first and second nip rolls 161, 162 are
swung about the pivot pins 58, 158, respectively may be
appropriately selected to move the vicinity of the first side edge
31 and the vicinity of the second side edge 32 nipped by these
pairs of the nip rolls, respectively, together with these rolls
outward as well as inward in the transverse direction of the first
continuous web 21.
[0045] As will be understood from the aforementioned description,
the method and the apparatus according to the present invention is
primarily in that a swinging direction and a swinging extent (i.e.,
swinging angle) of the first and second nip roll pairs 61, 62; 161,
162 are linked with the respective positions of the first and
second side edges 31, 32 of the first continuous web 21 detected by
the photoelectric sensor units 52, 152, respectively. More
specifically, the photoelectric sensor units 52, 152 are provided
immediately downstream of the respective roll units 63, 163 so that
a combined effect of the first and second nip roll pairs 61, 161;
161, 162 swinging in this direction and by this extent may be
rapidly fed back to the respective actuators 48, 148 and thereby
the first continuous web 21 may be rapidly and accurately
controlled. It is also possible to ensure a rapid position-change
of the first and second side edges 31, 32 by accelerating the
servomotors rotational velocities and thereby accelerating the
swinging velocities of the roll units 63, 163.
[0046] FIG. 9 is a view similar to FIG. 3, showing one preferred
embodiment of the present invention and FIG. 10 is a view similar
to FIG. 4, showing this embodiment. The edge controller 40
according to this embodiment is distinguished from that shown by
FIGS. 2 through 4 in that each of the first and second edge
controllers 41, 42 comprises a lower roll 262, 362 adapted to come
in contact with the lower surface of the first continuous web 21
and not an upper roll adapted to come in contact with the upper
surface of the first continuous web 21. While the positions at
which the lower rolls 262, 362 are provided are substantially the
same as those at which the second nip rolls 62, 162 of FIG. 4 are
provided, the first edge controller 41 according to the embodiment
shown by FIGS. 9 and 10 is distinguished from the previous
embodiment shown by FIG. 4 in that a bracket 264 is mounted on a
swing arm 249 so that the bracket 264 may swing about the arm 249.
The lower roll 262 mounted on the bracket 264 extends inward in the
transverse direction of the first continuous web 21 so as to
describe a rising slope (See FIG. 10) as the bracket 264
appropriately swings. This is true for the lower roll 362 of the
second edge controller 42. The first continuous web 21 is brought
into a state as shown by FIG. 10 as these lower rolls 262, 362 are
pressed against the vicinities of the first and second side edges
31, 32, respectively. Then, these rolls 262, 362 in- and outward
swing together with the respective swing arms 249, 349 in the
transverse direction of the first continuous web 21 and thereby
guide the first and second side edges 31, 32 to the desired
positions. According to this embodiment also, the positions
actually the first and second side edges 31, 32 passing after
having been guided by the rolls 262, 362 are detected by
photoelectric sensor units 252, 352 and actuators 248, 348 operate
in response to data supplied from these sensor units 252, 352 so
that the side edges 31, 32 may be guided to the predetermined
positions more accurately. Slopes at which the lower rolls 262, 362
should tilt may be appropriately adjusted taking account of
particular characteristics of the first continuous web 31 such as
flexibility, elasticity and slipperiness.
[0047] While the invention has been described hereinabove on the
basis of the embodiments in which the first and second side edges
31, 32 including the vicinities thereof of the first continuous web
21 are guided by the first and second end controllers 41, 42,
respectively, to the desired positions, the invention may be
implemented in a manner that only one of the side edges including
the vicinity of this side edge is guided to the desired position.
Without departing from the scope of the invention, an alternative
arrangement is also possible in which the first and second nip
rolls 61, 62 are shifted from each other in the machine direction
MD, i.e., one of the nip rolls is located upstream and the other is
located downstream in the machine direction MD. Factors such as
material, type of surface finish, length and diameter may be
appropriately selected depending on the manner in which the first
continuous web 21 has been processed and coated with adhesive, if
any. The roll may be formed from use of materials, for example,
sponge rubber obtained from various types of rubber such as
urethane rubber and silicone rubber or metallic material. The roll
may be subjected to a surface treatment such as a satin-like finish
to adjust a slipperiness relative to the first continuous web 21.
Means for position-detection of the first and second side edges 31,
32 is not limited to the photoelectric sensor unit as illustrated
and this photoelectric sensor unit may be replaced by the other
optical means or physical means. While the present invention has
been described with respect to the first continuous web 21 used for
the disposable diaper 1, the invention is applicable also to the
second continuous web 22 and the other types of continuous web used
for articles other than the diaper 1.
[0048] According to the present invention, the rotatable rolls used
to come in contact with the vicinities of the side edges of the web
continuously running in the machine direction and thereby to guide
these side edges in the cross direction are adapted to swing in-
and outward in the transverse direction of the web wherein the
direction and the extend (angle) of swing relative to the machine
direction are determined on the basis of the detected positions of
the respective side edges of the running web. According to the
present invention, the angle of the rolls relative to the machine
direction can be adjustably varied to vary a force tending to
broaden the web and at the same time the positions of the side
edges of the web can be forcibly and quickly varied by oscillating
the rolls. In this way, the side edges of the web can be easily and
accurately guided to the predetermined position.
* * * * *