U.S. patent application number 15/772448 was filed with the patent office on 2018-11-08 for method and device for removing defects on a stationary web of a packaging material.
The applicant listed for this patent is Tetra Laval Holdings & Finance S.A.. Invention is credited to Ingvar Andersson, Peter Ohman, Thomas Pettersson.
Application Number | 20180319612 15/772448 |
Document ID | / |
Family ID | 54476750 |
Filed Date | 2018-11-08 |
United States Patent
Application |
20180319612 |
Kind Code |
A1 |
Andersson; Ingvar ; et
al. |
November 8, 2018 |
METHOD AND DEVICE FOR REMOVING DEFECTS ON A STATIONARY WEB OF A
PACKAGING MATERIAL
Abstract
The invention relates to a method for removing defects on a
stationary web of a packaging material (106), comprising moving
said web of packaging material (106) through a repair line from a
first rotatable roller (121) to a second rotatable roller (122) in
a first direction, cutting off said web of packaging material (106)
at a first predetermined position, guiding said web of packaging
material (106) of said first roller (121) into a second direction,
wasting said web of packaging material (106) of said first roller
(121) by movement in said second direction to a waste station,
cutting off said web of packaging material (106) of said first
roller (121) at a second predetermined position, guiding said web
of packaging material (106) of said first roller (121) back into
said first direction, splicing said web of packaging material (106)
of said first roller (121) back together with said web of packaging
material (106) of said second roller (122) at said first
predetermined position, wherein said method is automated. The
invention further relates to a device for removing defects on a
stationary web of a packaging material.
Inventors: |
Andersson; Ingvar;
(LODDEKOPINGE, SE) ; Pettersson; Thomas;
(STOCKAMOLLAN, SE) ; Ohman; Peter; (LUND,
SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Tetra Laval Holdings & Finance S.A. |
Pully |
|
CH |
|
|
Family ID: |
54476750 |
Appl. No.: |
15/772448 |
Filed: |
October 24, 2016 |
PCT Filed: |
October 24, 2016 |
PCT NO: |
PCT/EP2016/075546 |
371 Date: |
April 30, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65H 2403/942 20130101;
B65H 2701/1944 20130101; B65H 26/02 20130101; B65H 21/00
20130101 |
International
Class: |
B65H 21/00 20060101
B65H021/00; B65H 26/02 20060101 B65H026/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 2, 2015 |
EP |
15192605.2 |
Claims
1. A method for removing defects on a stationary web of a packaging
material, comprising; moving said web of packaging material through
a repair line from a first rotatable roller to a second rotatable
roller in a first direction, cutting off said web of packaging
material at a first predetermined position, guiding said web of
packaging material of said first roller into a second direction,
wasting said web of packaging material of said first roller by
movement in said second direction to a waste station, cutting off
said web of packaging material of said first roller at a second
predetermined position, guiding said web of packaging material of
said first roller back into said first direction, splicing said web
of packaging material of said first roller back together with said
web of packaging material of said second roller at said first
predetermined position, wherein said method is performed under
control of a controller.
2. The method of claim 1, wherein guiding the web of packaging
material into a second position is performed by changing the
position of a guiding cylinder, and wherein guiding the web of
packaging material back into the first direction is performed by
returning the guiding cylinder to its initial position.
3. The method of claim 1, further comprising the step of stopping
said web of packaging material from moving in said first direction
before the step of cutting off said web of packaging material at
said first predetermined position.
4. The method of claim 1, further comprising the step of stopping
said web of packaging material from moving in said second direction
before the step of cutting off said web of packaging material at
said second predetermined position.
5. The method according to claim 1, further comprising the step of
rewinding said web of packaging material of said second roller from
said second roller onto a third rotatable roller.
6. The method according to claim 1, further comprising, as a first
step, the step of receiving information regarding said defects of
said web of packaging material from a control unit.
7. The method according to claim 1, further comprising the step of
controlling the tension of said web of packaging material in a
longitudinal direction of said web of packaging material by means
of a tension control device.
8. A device for removing defects on a stationary web of a packaging
material, comprising: a first rotatable roller and a second
rotatable roller configured to wind said web of packaging material
being wound from said first roller to said second roller in a first
direction, a guide adapted to guide said web of packaging material
of said first roller between said first direction and a second
direction, a cutter adapted to cut off said web of packaging
material at a first predetermined position and at a second
predetermined position, a wasting station arranged along said
second direction and adapted to collect said web of packaging
material being cut off between said first predetermined position
and said second predetermined position, and a splicer adapted to
splice said web of packaging material of said first roller back
together with said web of packaging material of said second
roller.
9. The device of claim 8, wherein said guide comprises at least one
guiding cylinder being configured to be moveable between at least
two positions, whereby guiding the web of packaging material into a
second position is performed by changing the position of the at
least one guiding cylinder, and whereby guiding the web of
packaging material back into the first direction is performed by
returning the at least one guiding cylinder to its initial
position.
10. The device according to claim 8, further comprising at least
one tension control device adapted to provide a pressure onto said
web of packaging material in a normal direction to the web of
packaging material surfaces so as to provide a tension of the web
of packaging material between said first rotatable roller and said
second rotatable roller.
11. The device according to claim 8, further comprising a third
roller, said web of packaging material being wound from said second
roller to said third roller so as to rewind said web of packaging
material.
12. The device according to claim 8, wherein said splicer comprises
an induction sealing device.
13. The device according to claim 8, further comprising a
controller arranged to control operation of the device.
Description
BACKGROUND ART
[0001] Within packaging engineering, consumer packages of a
disposable nature are commonly used for packaging and transporting
liquid foods, such as, for example, milk. So-called disposable
packages of this type are often made of a laminated packaging
material comprising a base layer of paper or cardboard and outer
liquid-tight layer of polyethylene. In special cases, such as with
particularly oxygen-sensitive foods, for example fruit juice, it is
necessary to supplement the packaging material with at least one
further layer of a material having oxygen-tight properties, and the
most common example of a supplementary material layer of this kind
is an aluminium foil between the paper or cardboard layer and one
of the two outer liquid-tight layers.
[0002] Consumer packages of this sort are nowadays very often
produced with the aid of modern rational packaging machines of the
sort which, from a web or from prefabricated blanks of the
packaging material, both form, fill and also seal finished
packages.
[0003] Formed, filled and sealed consumer packages are produced
from a web, for example, by the web firstly being transformed into
a tube by joining together of the two longitudinal edges of the web
into a longitudinal liquid-tight sealing joint (normally an overlap
sealing joint). The tube is continuously filled with the particular
food, for example milk, and is divided into connected pillow-shaped
pack units by repeated transversal heat sealings of the tube
transversely to the longitudinal axis of the tube below the fill
product level of the tube. The filled pillow-shaped pack units are
separated from one another by cuts in the transverse seals and may
subsequently be given the desired geometric shape by means of at
least one further forming and heat sealing operation. Well-known
examples of commercial consumer packages of this kind are Tetra
Brik and Tetra Classic packages, which are used to transport liquid
foods of the type milk, fruit juice, wine and cooking oil.
[0004] A laminated packaging material of the sort which is
described above is produced on an industrial scale from a roll of a
wide web of paper or cardboard. A web which is unwound from the
roll is led to a first work station where one side of the web, by
suitable printing technology, is provided with a recurring pattern
of an aesthetic and/or informative nature. In conjunction with or
directly after the printing, the web is also provided with a
likewise recurring pattern of weakening lines facilitating folding
(so called fold lines). In order to give the subsequently produced
disposable packages the desired shape and attractive appearance, it
is important that these two recurring patterns are applied to the
web in closest possible distance from each other.
[0005] The web provided with print and fold lines is led onward to
a subsequent work operation, in which the web is coated on both
sides with respective outer liquid-tight layers, usually
polyethylene. In certain cases, such as when the packaging material
is intended for packaging containers for particularly
oxygen-sensitive products, the packaging material is also provided
with at least one further layer of a material having such barrier
properties, for example an aluminium foil, on one side of the
packaging material between the paper or cardboard layer and one of
the two outer liquid-tight coatings.
[0006] Finally, the packaging material web is divided up into
individual partial webs, which are wound into finished packaging
rolls in order to produce the formed, filled and sealed packaging
containers.
[0007] In order to ensure that the packaging material in the
finished packaging rolls meets set quality requirements and is not
beset with serious faults and defects which could jeopardize the
chemical and/or mechanical protection of the finished packaging
containers, the packaging rolls are subjected to a quality control
in which the packaging material is repaired by removing parts with
defects, such as possible areas of missed polymer coating, pinholes
in material layers, defective aluminium foil, wrinkles, spots,
creasing defects or printing defects.
[0008] A repair line of the conventional sort has a rotatable
horizontal shaft at its one end and a corresponding rotatable
horizontal shaft at its other end. Between the rotatable shafts,
the repair line has a repair station, in which detected defects are
to be removed and treated on a stationary web of the packaging
material. Since a packaging material can quite often be beset with
a number of production faults and these production faults, in turn,
can be found at randomly spread points on one and the same
packaging material, this means that a web of the packaging material
which is led through the repair station can be subjected to several
repair operations, each at a different position along the web of
the packaging material roll, where defective packaging material is
removed in connection with the quality control. Between the repair
operations at stand-still of the web, the web needs to spooled at
high speed forward to the next position for a repair operation.
[0009] When a roll of packaging material is to be checked and
repaired, it is suspended from the horizontal rotatable shaft at
one end of the repair line. A web of the packaging material is
unwound from the suspended roll and is manually advanced for
winding onto the horizontal rotatable shaft at the other end of the
repair line. En route to the rotatable shaft at the other end, the
web is first led through a device for controlling the axial stress
of the web and onward from the device through the work station in
which detected production faults are to be treated on the web. Such
manual pulling of the web along a U-shaped loop through the known
roller arrangement is complicated, labour-intensive and
time-consuming whenever a new roll has to be checked and
repaired.
[0010] The actual repairing of the web is made by manually cutting
the web at two places before and after the portion of the in the
web of a packaging material having defaults, removing the part
between the cuts, and then manually splicing the ends together to
form a continuous web of a packaging material again. These
operations are time consuming and labour intensive.
[0011] An object of the invention is therefore to eliminate the
mentioned drawbacks and provide a device of the sort described in
the introduction, which device enables a significantly easier and
less time-consuming and labour-intensive method for repairing web
of a packaging material.
SUMMARY OF THE INVENTION
[0012] It is an object of the present invention to improve the
current state of the art, to solve the above problems, and to
provide an enhanced method for removing defects on a stationary web
of a packaging material thereby repairing the web. These and other
objects are achieved by a method for removing defects on a
stationary web of a packaging material, comprising: moving said web
of packaging material through a repair line from a first rotatable
roller to a second rotatable roller in a first direction, cutting
off said web of packaging material at a first predetermined
position, guiding said web of packaging material of said first
roller into a second direction, preferably by changing the position
of a guiding cylinder, wasting said web of packaging material of
said first roller by movement in said second direction to a waste
station, cutting off said web of packaging material of said first
roller at a second predetermined position, guiding said web of
packaging material of said first roller back into said first
direction, preferably by changing the position of the guiding
roller back to its initial position, and splicing said web of
packaging material of said first roller back together with said web
of packaging material of said second roller at said first
predetermined position, wherein said method is automated.
[0013] The automated method reduces labor needs and makes the
method faster. Costs are thereby saved in two ways, both by
reducing labor costs and by reducing the number of devices needed
for removing defects in webs of packaging material. Human errors
are also avoided, providing a higher degree of certainty that all
errors in a web of packaging material have been removed. Better
process control of the splices is also achieved such that the
register of packages is kept intact, i.e. the splice may be
positioned at a position of the web corresponding to exactly one
package such that only one package will end up having a splice.
[0014] The method may further comprise the step of stopping said
web of packaging material from moving in said first direction
before the step of cutting off said web of packaging material at
said first predetermined position. The method may further comprise
the step of stopping the web of packaging material from moving in
said second direction before the step of cutting off said web of
packaging material at said second predetermined position. Cutting
is easier to perform and the position of the cut will be more
precise if the web of packaging material is stopped before it is
cut at the first predetermined position.
[0015] The method according to the invention may further comprise
the step of rewinding said web of packaging material of said second
roller from said second roller onto a third rotatable roller. Since
the web of packaging material has to be used in the right direction
when used in a packaging machine as e.g. a filling machine for the
print of the web of packaging material to be in the correct
orientation on the package, the web of packaging material rolled
onto the second roll has to be re-winded onto the third roll before
it can be distributed further and finally used to make
packages.
[0016] The method according to the invention may further comprise,
as a first step, the step of receiving information regarding said
defects of said web of packaging material from a control unit. An
inline quality control device may e.g. be used at an earlier stage
in a factory for web of packaging material for scanning the web of
packaging material for errors. The lengthwise location of the
errors may thus be logged and stored together with the
identification of the reel with web of packaging material. If
errors are detected, the reel will be moved to a device for
removing defects and the method described herein will be applied to
the web of packaging material.
[0017] The method according to the invention may further comprise
the step of controlling the tension of said web of packaging
material in a longitudinal direction of said web of packaging
material by means of a tension control device. Tension control is
important so that the web of a packaging material is not damaged
during the repairing operation.
[0018] The invention further relates to a device for removing
defects on a stationary web of a packaging material, comprising a
first rotatable roller and a second rotatable roller, said web of
packaging material being wound from said first roller to said
second roller in a first direction, a guiding unit adapted to guide
said web of packaging material of said first roller between said
first direction and a second direction, preferably by means of a
moveable guiding cylinder forming part of the guiding unit, a
cutting device adapted to cut off said web of packaging material at
a first predetermined position and at a second predetermined
position, a wasting station arranged along second direction and
adapted to collect said web of packaging material being cut off
between said first predetermined position and said second
predetermined position, and a splicing unit adapted to splice said
web of packaging material of said first roller back together with
said web of packaging material of said second roller, wherein said
device is automated.
[0019] The device according to the invention may further comprise
at least one tension control device, or dancer roller as they are
called, adapted to provide a pressure onto said web of packaging
material in a normal direction to the web of packaging material
surfaces in order to provide a tension of the web of packaging
material between said first rotatable roller and said second
rotatable roller.
[0020] The device may further comprise a third roller, said web of
packaging material being wound from said second roller to said
third roller so as to rewind said web of packaging material, and a
control unit arranged to control the device.
[0021] The splicing unit of the device may comprise an induction
sealing device for sealing the open ends together in the splicing
unit.
[0022] A person skilled in the art understands that the same
advantages as discussed in relation to the features of the
inventive method are also true for the corresponding features of
the inventive device.
[0023] Generally, all terms used in the claims are to be
interpreted according to their ordinary meaning in the technical
field, unless explicitly defined otherwise herein. All references
to "a/an/the [element, device, component, means, step, etc.]" are
to be interpreted openly as referring to at least one instance of
said element, device, component, means, step, etc., unless
explicitly stated otherwise.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The above objects, as well as additional objects, features
and advantages of the present invention, will be more fully
appreciated by reference to the following illustrative and
non-limiting detailed description of preferred embodiments of the
present invention, when taken in conjunction with the accompanying
drawings, wherein:
[0025] FIG. 1 is a schematic view of a device for removing defects
on a stationary web of a packaging material.
[0026] FIG. 2 is a schematic view of a device for removing defects
on a stationary web of a packaging material where the web of a
packaging material is cut and fed to waste station.
[0027] FIG. 3 is a schematic view of a tension control device
adapted to be placed in the device of FIG. 1 and FIG. 2 in some
embodiments.
[0028] FIG. 4 is a block diagram showing a method for removing
defects on a stationary web of a packaging material.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
[0029] FIG. 1 shows a device for removing defects on a stationary
web of a packaging material. A reel 102 of stationary web of a
packaging material 106 is placed on a first rotatable roller 121.
At start-up, the leading edge of the stationary web 106 is pulled
by a robotic arm (not shown) to the second rotatable roller 122.
The reel 102 of stationary web of a packaging material 106 is
spooled from the first rotatable roller 121 into a second reel 104
on the second rotatable roller 122.
[0030] The stationary web 106 is bent around a present pull- and
break arrangement 110, which comprises a first guiding cylinder 112
and a second guiding cylinder 114, both being arranged to rotate
around a first rotational axis 116 and a second rotational axis 118
respectively. As will be explained below, at least one of the
guiding cylinders 112, 114 are moveble such that the web path can
be changed depending on the position of the at least one guiding
roller 112, 114.
[0031] During a doctoring process the operative position of the
pull- and break arrangement 110 is such that the web is guided
along an S-shaped path through the arrangement 110. In the present
setup the first guiding cylinder 112 is arranged above the second
guiding cylinder 114. The web is guided below and around about half
the second cylinder on the far side thereof, as seen from the first
reel 102 before following the second cylinder around about half its
circumference before continuing towards a doctoring station 108 and
the second reel 122. The first guiding cylinder 112 is illustrated
in full lines while various positions for the second guiding
cylinder 114 are shown in dotted lines. As seen in FIG. 2, there is
a position P1 corresponding to the position as shown in FIG. 1;
i.e. an "operative position" for guiding the web 106 towards the
second reel 122. There is a position P2 which corresponds to an
"engagement position" which is more of an intermediate position
passed when moving between the other positions. There is a "waste
position" P3 in which the arrangement 110 will guide a passing web
106 downwards. There is also a "thread position" P4 in which the
second guiding cylinder 114 is fully disengaged with the first
guiding cylinder 112 such that a web 106 may be conveniently
arranged (or threaded) through the arrangement 110 merely by
following a rectilinear path from the first reel 121 to the second
reel 122. The first guiding cylinder 112 is arranged to rotate
around a first axis 116. The second guiding cylinder 114 is
arranged to rotate around a second axis 118. The first and the
second guiding cylinders are arranged in parallel, i.e. having
parallel rotational axes. In one or more embodiments both guiding
cylinders 112, 114 are suspended from one side axial thereof only,
basically corresponding to the rotational axis of each cylinder
having one end attached to a constructional arrangement while the
second end is free.
[0032] In the view of FIG. 2 the second guiding cylinder 114 has
been arranged in the waste position P3. In this position the second
guiding cylinder 114 is in contact with the first guiding cylinder
112, with the intermediate of the web 106, and the tangent of the
contact, i.e. nip, is directed downwards, enabling guiding of the
web 106 in an alternative direction. In the present embodiment the
web 106 is directed towards a waste assembly schematically
indicated by the recycling bin. Wasting of packaging material may
be the first operation after threading of a web. This means that
the second guiding cylinder 114 is moved from the position P4, to
position P2, and then to the waste position P3. One other example
could be that the second guiding cylinder 114 is moved from the
first position P1 directly to the waste position P3. No matter the
scenario the present arrangement nevertheless enables the second
guiding cylinder 114 to assume the position P3.
[0033] When the automatic repairing process is finished, the
packaging material 106 spooled onto the reel 122 is spooled onto
the reel 123, see FIG. 2, so that the packaging material is wound
in the same order as when entering the device for removing defects.
The device of the invention further comprises a control unit 125,
controlling the automated process of the entire device for removing
defects on a stationary web of a packaging material.
[0034] FIG. 3 illustrates a tension control device 201. A stoppage
of the web can generally be performed without major problems, but,
on the other hand, problems and disruptions quite often arise in
connection with the restart of the web after each stoppage and
standstill. Problems and disruptions of this sort are at least
partially associated with the fact that a moving web 106 of a
packaging material cannot be stopped instantaneously, but rather
that a slowdown and stoppage of the web, due to inherent inertia
and other dynamic effects, takes place after a continuous
retardation process, during which a growing accumulation or loop of
the slowing web is formed in conjunction with or immediately before
the repair station 108. When the web 106, after its standstill, is
then started and reaccelerated, this accumulation or loop of the
web will gradually shrink and finally disappear altogether. At the
same moment, the web will thus be subjected to an axial pull, which
at the same time subjects the web to an instantaneous strong axial
force in the motional direction of the web.
[0035] In order to prevent this instantaneous axial force from
becoming so large that it even exceeds the ultimate tensile
strength of the particular web, the repair line of FIG. 1 and FIG.
2 may be equipped with a tension control device 201 according to
the invention for controlling axial forces upon a web and keeping
these at a level below this ultimate tensile strength. The tension
control device 201 may e.g. be placed before the pull-and-brake
device 110 shown in FIG. 1 and FIG. 2, i.e. at a position between
the first reel 121 and the pull- and break assembly 110.
[0036] The tension control device 201 has a first cylinder 204,
which is rotatable about a first horizontal shaft, a second
cylinder 205, which is rotatable about a second horizontal shaft,
and a third rotatable cylinder 203, which is rotatable about a
third horizontal shaft. The third rotatable cylinder 203 is
movable, in response to axial forces acting upon the web at any
moment, between a lower position and an upper position along an
arc-shaped motional path (shown in dashed representation) in the
vertical plane between the two first and second rotatable cylinders
204 and 205, the arc being defined by the end of the arm 202 that
the third cylinder 203 is attached to.
[0037] In order to counter strong axial forces upon the web in
connection with pulls when the speed of the web is accelerated, the
third rotatable cylinder 203 is biased with a freely adjustable
force which acts in the direction of the motion of the third
cylinder from the lower position. Such a counterforce can be
produced in a known manner with both pneumatic and hydraulic and
mechanical means which act directly upon the fourth rotatable
shaft. In order to avoid rupture of the web due to excessively
strong pulls and axial forces upon the web, as is described above,
this counterforce must be set at a value below the particular
ultimate tensile strength of the web. If the web, for example, has
an ultimate tensile strength in the order of magnitude of 20,000 N,
then the counterforce can be set at a value amounting to just one
tenth ( 1/10) of this, such as 1800-2000 N, in order thus to enable
the third cylinder to be displaced, if the web is acted upon by
axial forces, already far below the ultimate tensile strength of
the web.
[0038] FIG. 4 illustrates the automated method for removing defects
on a stationary web of a packaging material performed by the device
of FIGS. 1-3. The device receives information regarding defects of
the web of packaging material from a control unit indicating to the
device where defects are present on the packaging material. The
packaging material is moved from a first rotatable roller to a
second rotatable roller and stopped from moving in first direction
at a position corresponding to the information received regarding
locations of defects. The web of packaging material is then cut off
at that first predetermined position, as indicated by the position
of the cutting knife 124 in FIG. 1 or 2. The cutting knife 124 is
preferably a sharp tool being moveable across the width of the web
106 for separating the web into a leading end, and a trailing end.
The web of packaging material is thereafter guided into a second
direction to a waste by changing the position of the second guiding
roller 114. The web of packaging material of said first roller
containing defect is thereby moved in the second direction into a
waste station. When the defect section has been wasted, the web of
packaging material is stopped from moving into the waste station in
the second direction. The web of packaging material is cut off at
that second predetermined position where defects are no longer
present. This may e.g. be performed by moving the cutting knife 124
towards the right in FIG. 2, such that it engages at a position
upstream the pull- and break assembly 110, and activating the
cutting knife 124 thus providing a lateral cut across the width of
the web 106. The web of packaging material of said first roller is
again guided into the first direction by returning the second
guiding roller 114 to its position P1 and pulling of the packaging
material by the robotic arm, and is spliced back together,
preferably by means of induction heating or other heat-generating
device, with the web of packaging material of the second roller 122
at the first predetermined position by means of repair station 108.
The defective parts have thus been automatically cut off and been
removed and the web packaging material has been reattached.
[0039] The skilled person realizes that a number of modifications
of the embodiments described herein are possible without departing
from the scope of the invention, which is defined in the appended
claims.
* * * * *