U.S. patent application number 09/818023 was filed with the patent office on 2001-12-06 for paperboard cartons with laminated reinforcing ribbons and transitioned scores and method of making same.
Invention is credited to Zoeckler, Michael D..
Application Number | 20010048022 09/818023 |
Document ID | / |
Family ID | 25224443 |
Filed Date | 2001-12-06 |
United States Patent
Application |
20010048022 |
Kind Code |
A1 |
Zoeckler, Michael D. |
December 6, 2001 |
Paperboard cartons with laminated reinforcing ribbons and
transitioned scores and method of making same
Abstract
A method of making reinforced paperboard cartons comprises the
steps of advancing a web of paperboard along a path and
progressively laminating at least one ribbon of reinforcing
material to the advancing web of paperboard. The ribbon of
reinforcing material, which also may be paperboard, has a width
less than the width of the web of paperboard and is applied with
adhesive at a selected location across the width of the web. The
web and its laminated ribbon are cut into sheets of a predetermined
size and the sheets are die-cut and scored with fold lines to form
carton blanks. The fold lines may transition from non-reinforced to
reinforced portions of the blank and a special transition zone is
contemplated to accommodate the transition. The carton blanks are
subsequently formed into cartons for receiving articles, the
laminated reinforcing material providing reinforcement in selected
portions of the cartons. Multiple ribbons and multiple layers of
ribbons may be laminated to the web in respective selected
locations to provide reinforcement in more than one portion of the
cartons. Reinforcing ribbons may be deformed or altered to exhibit,
for instance, corrugations or perforations prior to being adhered
to the base sheet. Reinforced cartons and carton blanks made by the
method also are provided.
Inventors: |
Zoeckler, Michael D.;
(Roswell, GA) |
Correspondence
Address: |
Steve M. McLary
Riverwood International Corporation
3350 Riverwood Parkway, SE, Suite 1400
Atlanta
GA
30339
US
|
Family ID: |
25224443 |
Appl. No.: |
09/818023 |
Filed: |
March 27, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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09818023 |
Mar 27, 2001 |
|
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09559704 |
Apr 27, 2000 |
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Current U.S.
Class: |
229/199 |
Current CPC
Class: |
B31B 50/142 20170801;
Y10T 156/1016 20150115; Y10T 156/101 20150115; B31B 2105/001
20170801; B31B 50/256 20170801; Y10T 156/1056 20150115; B31F 1/26
20130101; B65D 5/48024 20130101; B31B 50/14 20170801; B31B 50/8129
20170801; B31B 50/8126 20170801; B31F 1/22 20130101; B65D 5/566
20130101; B65D 5/445 20130101 |
Class at
Publication: |
229/199 |
International
Class: |
B65D 005/42 |
Claims
What is claimed is:
1. A method of making reinforced paperboard cartons comprising the
steps of: (a) advancing a web of paperboard along a path, the web
of paperboard having a width; (b) progressively applying at least
one ribbon of reinforcing material to the advancing web of
paperboard to form a reinforced region, the ribbon having a width
less than the width of the web of paperboard and an edge; (c)
scoring fold lines in the web of paperboard, at least one of the
fold lines crossing the edge of the ribbon of reinforcing material
to define a fold line having a first section within the reinforced
region and a second section outside the reinforced region, the
first section of the fold line being wider than the second section
of the fold line; and (e) forming a transition zone between the
first and second sections of the fold line.
2. The method of claim 1 and where in step (e) the transition zone
comprises a widening of the fold line from the narrower second
section of the fold line to the wider first section of the fold
line.
3. The method of claim 2 and where in step (e) the fold line widens
smoothly from the second to the first sections of the fold
line.
4. The method of claim 2 and wherein the edge of the reinforcing
ribbon is located within the transition zone nearer the wider
portion of the fold line.
5. The method of claim 1 and wherein step (c) further comprises
impressing the paperboard with a multi-point scoring rule having a
narrower section outside the reinforced region and a wider section
inside the reinforced region.
6. The method of claim 5 and wherein the scoring rule is part of a
platen die cutter.
7. The method of claim 5 and wherein the scoring rule is part of an
in-line rotary die cutter.
8. The method of claim 5 and wherein step (c) further comprises
locating a counter plate beneath the scoring rule, the counter
plate being formed with a groove aligned with the scoring rule, the
groove having a narrower section aligned with the narrower section
of the scoring rule and a wider section aligned with the wider
section of the scoring rule.
9. The method of claim 8 and where in step (e) the transition zone
is formed by gradually widening the groove in the counter plate
from its narrower section to its wider section.
10. The method of claim 9 and wherein the junction between the
narrower and the wider sections of the scoring rule is aligned with
the wider end of the transition zone.
11. A method of scoring a fold line in a paperboard carton blank
having a base sheet of paperboard and a reinforced region formed by
a reinforcing ribbon laminated to the base sheet wherein the fold
line transitions from outside the reinforced region to inside the
reinforced region, the method comprising the steps of: (a)
providing a multi-point scoring rule having a narrower first
section for scoring the portion of the fold line outside the
reinforced region and a wider second section for scoring the
portion of the fold line within the reinforced region; and (b)
impressing the paperboard carton blank with the multi-point scoring
rule.
12. The method of claim 11 and where in step (b) the paperboard
carton blank is sandwiched between the multi-point scoring rule and
a counter plate, the counter plate formed with a groove aligned
with the scoring rule with the groove having a narrower section
aligned with the narrower section of the scoring rule and a wider
section aligned with the wider section of the scoring rule.
13. The method of claim 12 and wherein the groove in the counter
plate is further formed with a transition region between its
narrower section and its wider section to form a fold line with a
corresponding transition region at the edge of the reinforcing
ribbon.
14. The method of claim 13 and wherein the transition region of the
groove comprises a gradually widening section of the groove from
its narrower section to its wider section.
15. The method of claim 14 and wherein the transition region of the
groove is about 0.125 inches long.
16. A carton blank comprising: a base sheet of paperboard material
having a width; at least one ribbon of reinforcing material having
an edge a width less than the width of the base sheet, said ribbon
of reinforcing material being laminated to the base sheet at a
predetermined position thereon to form a reinforced region of the
carton blank; at least one fold line scored in the carton blank,
said fold line crossing from a location within said reinforced
region of said carton blank to a location outside said reinforced
region.
17. A carton blank as claimed in claim 16 and wherein the fold line
is relatively wider within said reinforced region of said carton
blank and relatively narrower outside of said reinforced
region.
18. A carton blank as claimed in claim 17 and wherein said fold
line is formed with a transition zone between its relatively wider
and its relatively narrower sections.
19. A carton blank as claimed in claim 18 and wherein said edge of
said reinforcing ribbon crosses said fold line within said
transition zone.
20. A carton blank as claimed in claim 19 and wherein said fold
line widens within said transition zone from its relatively
narrower section to its relatively wider section.
21. A carton blank as claimed in claim 20 and wherein said fold
line widens gradually within said transition zone.
22. A carton blank as claimed in claim 20 and wherein said edge of
said reinforcing ribbon is located nearer the wider portion of said
transition zone.
23. A carton blank as claimed in clam 18 and wherein said
transition zone is about 0.125 inches long.
24. A scoring rule assembly for use in a die cutter for scoring
multi-width fold lines in carton blanks, said scoring rule
comprising: a first section formed by a scoring blade having a
first thickness; and a second section formed by a scoring blade
having a second thickness greater than said first thickness.
25. A scoring rule assembly as claimed in claim 24 and wherein said
first section and said second section meet at a joint.
26. A scoring rule assembly as claimed in claim 25 and wherein the
joint is a butt joint.
27. A scoring rule assembly as claimed in claim 24 and further
comprising a platen die cutter having a head, said scoring rule
being disposed in said head of said platen die cutter.
28. A scoring rule assembly as claimed in claim 24 and further
comprising an in-line rotary die cutter having a drum, said scoring
rule being disposed in said drum of said in-line rotary die
cutter.
29. A scoring rule assembly as claimed in claim 24 and further
comprising a counter plate against which said scoring rule is
impressed to score fold lines in carton blanks, said counter plate
being formed with at least one groove aligned with said scoring
rule, said groove having a relatively narrower section aligned with
said first section of said scoring rule and a relatively wider
section aligned with said second section of said scoring rule.
30. A scoring rule assembly as claimed in claim 29 and wherein said
groove is formed with a transition region aligned with the junction
of said first and second sections of said scoring rule.
31. A scoring rule assembly as claimed in claim 30 wherein said
groove gradually widens from its relatively narrower section to its
relatively wider section to define said transition zone.
32. A scoring rule assembly as claimed in claim 31 and wherein said
junction of said first and second section of said scoring rule is
aligned substantially with the wider end of said transition
zone.
33. A method of making reinforced paperboard carton blanks
comprising the steps of: (a) advancing a web of paperboard along a
path, the web of paperboard having a width; (b) advancing at least
one ribbon of reinforcing material along a path, said reinforcing
material having a width less that the width of said web of
paperboard; (c) progressively deforming the ribbon of reinforcing
material; and (d) progressively laminating the deformed ribbon of
reinforcing material to the web of paperboard to form a reinforced
paperboard carton blank.
34. The method of claim 33 and wherein step (c) comprises passing
the ribbon of reinforcing material between a pair of impression
cylinders.
35. The method of claim 34 and wherein the surfaces of said
impression cylinders are configured to form an array of
perforations in said ribbon of reinforcing material.
36. The method of claim 34 and wherein the surfaces of said
impression cylinders are configured to form longitudinal flutes in
said ribbon of reinforcing material.
37. The method of claim 34 and wherein the surfaces of said
impression cylinders are configured to form transverse corrugations
in said ribbon of reinforcing material.
38. A ribbon reinforced carton blank comprising a base sheet of
paperboard having a width, at least one ribbon of reinforcing
material having a width less than the width of said base sheet and
being laminated to said base sheet at a selected location thereon,
said ribbon of reinforcing material being deformed.
39. A ribbon reinforced carton blank as claimed in claim 38 and
wherein said ribbon of reinforcing material is deformed so as to
exhibit an array of perforations.
40. A ribbon reinforced carton blank as claimed in claim 38 and
wherein said ribbon of reinforcing material is deformed so as to
exhibit longitudinal flutes.
41. A ribbon reinforced carton blank as claimed in claim 38 and
wherein said ribbon of reinforcing material is deformed so as to
exhibit transverse corrugations.
Description
REFERENCE TO RELATED APPLICATION
[0001] This is a continuation-in-part of co-pending U.S. patent
application Ser. No. 09/559,704, filed on Apr. 27, 2000.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to article packaging and
more specifically to the fabrication of paperboard cartons into
which a plurality of articles can be packaged for transport and
sale.
[0004] 2. Description of the Related Art
[0005] Paperboard cartons of various design and construction have
long been used by the packaging industry to package a wide variety
of articles such as canned and bottled drinks, food items,
detergents, and more. In general, paperboard cartons are erected or
converted from paperboard blanks that are die-cut or rotary-cut
from long webs of paperboard as the paperboard is drawn
progressively from large rolls. Fold lines are scored in the blanks
to define the various panels of the cartons and to aid in the
conversion of the blanks into their final carton shapes.
Traditionally, the fold lines are formed by an array of thin metal
blades known as a "rule" embedded within the head of a platen die
cutter or within the drum of a rotary die cutter. These blades of
the rule extend partially into aligned groves or slots formed in a
counter plate that underlies a paperboard blank to crease and form
scores in the blank.
[0006] In some cases, such as in beer and soft drink packaging,
carton blanks are pre-glued and provided to packagers in the form
of substantially flat knocked down sleeves that are erected in a
packaging machine into open ended cartons for receiving articles.
In other cases, the blanks are provided in a completely flat
configuration, in which case the blanks typically are folded around
groups of articles and glued by the packaging machine. In either
case, the conversion of blanks usually is performed at the time of
packaging by specialized conversion stations that are part of large
continuous packaging machines. In this way, the flat or pre-glued
and knocked down paperboard blanks can be shipped economically to
the packager in palletized stacks.
[0007] When making paperboard carton blanks from a web of
paperboard, the web usually is pre-cut to a specified predetermined
width from a wider web of paperboard stock. The pre-cutting of the
web to width generally takes place at the paper mill. The width of
the web in each case is dictated by the size and shape of the
cartons to be made from the web and is specified to the paper mill
by a carton fabricator. For example, a web of paperboard stock may
have a width of 64 inches whereas a particular carton blank may
require a web 48 inches wide. In such an example, a strip of
paperboard 16 inches wide (or two strips that total 16 inches in
width) typically will be cut from the web of paperboard stock by
the paper mill to form the required 48 inch-wide web. These strips,
known in the industry as "trim," traditionally have had reduced
value and in some cases are sold at low cost for secondary uses
such as the making of shirt collar stiffeners used in the garment
industry. In general, the creation of trim in the process of making
paperboard web has long been a problem for paperboard
manufacturers.
[0008] Occasionally, errors by paperboard manufacturers result in
rolls of paperboard web that may be substandard for a variety of
reasons and thus not usable in the fabrication of paperboard
cartons. In other cases, paperboard web manufactured for a
particular customer may not meet specifications and thus cannot
readily be used. Such substandard and off-spec paperboard is known
in the industry as "cull" and also has had reduced value, sometimes
being reconstituted into pulp for making new paper. In general,
there has been little use for trim and cull in the paperboard
carton making industry.
[0009] In many packaging applications, the cartons into which
articles are packaged must exhibit enhanced strength at least in
selected regions to contain the articles securely. This is
particularly true in cases where the articles are relatively heavy
and are stacked atop one another in their cartons for shipment and
sale. For example, canned and bottled beverages, which typically
may be packaged in groups of 6, 12, or 24, are inherently
relatively heavy and typically are stacked several cartons high on
pallets for shipment to retail stores. The cartons into which these
beverages are packed therefore must be strong enough to hold the
groups of cans or bottles securely together and to resist tearing
or "blowing out" even when under the substantial weight of several
layers of stacked cartons. In other applications, such as, for
example, cartons of boxed fruit drinks, the cartons themselves must
provide at least some of the strength and rigidity necessary to
resist crushing when layers of cartons are stacked atop one
another. This is because the individual drink containers lack the
rigidity of bottles or cans and cannot themselves bear the entire
weight of a stack of cartoned fruit drinks.
[0010] In applications such as these, traditional paperboard
cartons have sometimes proven inadequate to provide the required
strength and rigidity. As a result, many packagers have turned to
carton materials known in the industry as small flute corrugated
and/or micro-flute, and/or B-corrugated material, which are
corrugated paper products. In the balance of this specification,
all such corrugated material will be referred to as and included
within the definition of "micro-flute." In general, micro-flute is
fabricated from a core of paper material formed with a large number
of relatively small corrugations sandwiched between facing sheets
of flat paper. Micro-flute does tend to provide the strength and
rigidity required in many packaging applications; however, it also
has significant inherent problems and shortcomings including its
generally higher price compared to paperboard. In addition, carton
blanks made of micro-flute can be more expensive in some weights to
ship than paperboard blanks because their greater thickness limits
the number of blanks that can be stacked on standard sized pallet.
Further, in some cases, specialized conversion machinery is
required to convert the blanks to cartons, increasing the cost of
the packaging process. Finally, the printing of high quality
graphics on micro-flute has sometimes proven to be difficult. Thus,
micro-flute has not provided a completely satisfactory solution as
a carton making material in packaging applications where enhanced
carton strength, rigidity, and printability is required.
[0011] Attempts have been made to improve the strength and rigidity
of paperboard cartons to provide a viable alternative to
micro-flute where added strength and rigidity are required. These
attempts have included laminating two or more webs or sheets of
standard thickness paperboard together to create thicker multi-ply
paperboard from which carton blanks can be cut. However, while this
approach increases the strength and rigidity of resulting cartons,
it essentially results in a doubling of the paperboard required per
carton and a consequent increase in material and shipping costs.
Further, the formation of score or fold lines in and the folding of
multiple ply paperboard cartons can be problematic due to the added
thickness of paperboard that must be folded. For these and other
reasons, such multi-layer laminated paperboard has not proven to be
an acceptable alternative to micro-flute.
[0012] Other attempts to provide alternatives to micro-flute have
included the separate fabrication of custom stiffening inserts,
which are installed in individual cartons after the cartons are
converted from carton blanks. Such inserts have been used, for
example, in detergent cartons to provide added strength for
stacking and an internal moisture barrier and in beverage cartons
to provide separators. However, installing inserts requires
expensive specialized machinery, increases material and packaging
costs, and can slow the packaging process significantly.
[0013] A problem with cartons in general, including micro-flute and
paperboard cartons, is that they tend to tear and fail in areas of
particularly high stress such as in certain corners of the cartons
where folded panels meet. Such tears, once started, often can
spread, resulting in the separation of carton panels and ultimately
in carton blow-out. Attempts to address this problem have included
providing double folding flaps and/or tongues in carton blanks to
reinforce the corners and, in some cases, gluing special corner
reinforcements in cartons to inhibit tearing. Such attempts have
not been completely successful.
[0014] In some situations, a product manufacturer may specify that
cartons into which products are to packaged be printed on the
inside in addition to the printing of logos and graphics on the
outside of the carton. For example, a manufacturer may want to
print contest rules, product instructions, special incentive
coupons, or the like on the inside of product cartons. In the past,
such interior printing has required that relatively expensive and
time-consuming two-sided printing techniques be used to print both
sides of a web from which the carton blanks are cut. Further, since
interior surfaces of cartons generally are not coated for printing,
the quality and character of printing available for interior carton
surfaces has been limited.
[0015] A need therefore exists for an improved paperboard carton
that provides the strength and rigidity of cartons made from
micro-flute at a competitive cost. A related need exists for an
efficient and cost effective method of making such paperboard
cartons that uses traditional paperboard carton fabrication
machinery and that does not substantially increase material costs
associated with the fabrication process. Further needs exist for
more efficient methods of providing paperboard carton inserts such
as stiffeners and dividers and for providing higher quality
printing visible on the interior surfaces of cartons where such
printing is desired. It is to the provision of a method of making a
paperboard carton and a resulting carton that addresses these and
other needs and that overcomes the problems of the prior art that
the present invention is primarily directed.
SUMMARY OF THE INVENTION
[0016] Briefly described, the present invention, in a preferred
embodiment thereof, comprises a method of making reinforced
paperboard cartons having enhanced strength and rigidity similar to
that of micro-flute in selected regions where strength and rigidity
are required. The method comprises the steps of advancing a web of
paperboard along a path. The web of paperboard has a predetermined
width according to the size of cartons to be made and preferably is
drawn from a large roll of paperboard. The web of paperboard may or
may not be pre-printed on the side that will become the outside of
the finished carton with, for example, logos and graphics,
according to application specific requirements. The web also may be
printed on both sides if desired.
[0017] As the web of paperboard is advanced along the path, one or
more ribbons of reinforcing material, each having a width less than
the width of the paperboard web, is progressively applied to the
web. Each ribbon preferably is applied with adhesive to the side of
the web that will become the inside of the finished cartons and is
positioned at a predetermined location across the width of the web.
The location of each ribbon is selected to provide multiple layers
or laminations of material in specific regions of finished cartons
where enhanced strength and/or rigidity will be required such as,
for example, in the side walls of the carton. Preferably, the
ribbons of reinforcing material also are formed of paperboard and
most preferably are pre-cut or slit to desired widths from
paperboard trim or cull that otherwise may have reduced value. The
ribbons are drawn from rolls that are pre-positioned to locate the
ribbons properly on the web, advanced along and adjacent to the
path of the web, supplied with adhesive on one side, and
progressively brought into engagement with and compressed against
the advancing paperboard web to adhere the ribbons to the web. In
one embodiment, one or more of the ribbons may be pre-printed on
one or both sides with application specific indicia that ultimately
will be exposed on the inside of finished cartons.
[0018] After the reinforcing ribbons are laminated to the advancing
web, the web may be cut into sheets of a predetermined size. The
sheets subsequently may be die-cut and scored with fold lines as
required to form carton blanks defining the various panels and tabs
that ultimately will become the walls of finished cartons. In this
regard, unique multi-width fold lines may be formed where a fold
line transitions across the edge of a reinforcing ribbon. Such
multi-width fold lines may be scored according to the invention
with equally unique multi-point scoring rules in a platen or
in-line rotary die cutter. The cut and scored carton blanks may be
palletized and shipped to packagers, where the blanks are converted
into cartons and packed with articles such as, for example,
beverage containers or food items. When converted to cartons, the
previously positioned and applied paperboard reinforcing ribbons
form multiple layers or laminations of paperboard in selected
portions of the cartons such as, for example, in their sides, where
enhanced structural integrity is required. By appropriately
selecting, sizing, and positioning the reinforcing ribbons,
paperboard cartons having strength and rigidity comparable or
superior to that provided by cartons made of micro-flute are
obtained. Further, through judicious use of trim and cull in making
the reinforcing ribbons, paperboard cartons made by the method of
the present invention can be economically viable alternatives to
cartons made of micro-flute.
[0019] In addition to providing paperboard cartons comparable in
strength to micro-flute cartons, the present invention offers
possibilities that are not obtainable with micro-flute. For
example, the reinforcing ribbons of the present invention may be
pre-printed on one side with high-quality graphics and indicia that
is visible on the inside of finished cartons, all without requiring
a two-sided printing process. Further, only a portion of one or
more ribbons may be adhered to the paperboard web, with another
portion being inwardly foldable to define interior carton
structures such as stiffeners and dividers without the need for the
insertion of a separate liner. If desired, the ribbons may be
passed through special embossing or perforating rollers prior to
being adhered to the base sheet to provide, for example,
reinforcing ribbons that are corrugated, fluted, or perforated of
offer enhanced strength or adhesion properties. Additional
advantages are also provided, as will become more apparent
below.
[0020] Thus, a unique reinforced paperboard carton and method of
its manufacture is now provided that successfully addresses the
problems and shortcomings of the prior art. The carton has
structural integrity comparable to cartons previously made of
micro-flute but is made of traditional paperboard material, which
is easily converted to cartons in packaging machines with standard
conversion machinery. The carton is economically competitive with
cartons formed of micro-flute because of the unique use of trim and
cull in forming the reinforcing ribbons and because the method of
making the carton blanks can be practiced with existing paperboard
fabrication machinery. The forgoing and other features, objects,
and advantages of the invention will become more apparent upon
review of the detailed description of the preferred embodiments set
forth below when taken in conjunction with the accompanying drawing
figures, which are briefly described as follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a perspective illustration of a method of making
reinforced paperboard carton blanks that embodies principles of the
present invention in a preferred form.
[0022] FIG. 2 is a cross-sectional view showing the profile of a
carton blank made by the method illustrated in FIG. 1.
[0023] FIG. 3 is a perspective view of a possible configuration of
a paperboard carton blank that embodies principles of the
invention.
[0024] FIG. 4 is a sectional view illustrating a portion of a
reinforced paperboard carton blank according to the invention and
illustrating a preferred placement of a score line relative to the
edge of an adjacent reinforcing ribbon.
[0025] FIG. 5 is a sectional view of the portion of the reinforced
paperboard carton blank of FIG. 3 with the blank folded along its
fold line as it appears when the blank is converted to a
carton.
[0026] FIGS. 6a through 6h are cross-sectional views of carton
blanks made by the method of the invention illustrating some of the
possible configurations in which ribbons of reinforcing material
may be applied to a paperboard base sheet.
[0027] FIG. 7 is a perspective view of one configuration of a
carton that embodies principles of the invention illustrating the
results of pre-printing ribbons of reinforcing material with
indicia according to one embodiment of the invention.
[0028] FIG. 8 is a perspective partially sectioned view
illustrating another possible configuration of a carton formed by
the method of the invention and showing various aspects of the
invention.
[0029] FIG. 9 is a top plan view of a carton blank according to the
invention wherein fold lines are specially configured to transition
from the thinner base sheet to the thicker laminated reinforced
regions.
[0030] FIG. 10 is an enlarged view of a fold line transition
illustrated in FIG. 9
[0031] FIG. 11 is a partial perspective view of a scoring rule and
corresponding counter plate configuration usable to form the
transitioned fold lines of FIGS. 9 and 10.
[0032] FIG. 12 is a partial perspective view of a section of a
carton blank illustrating the folding of the blank along a
transitioned fold line.
[0033] FIG. 13 is a longitudinally sectioned view through a scoring
rule and counter plate configuration for creating transitioned fold
lines according to the invention.
[0034] FIG. 14 is a perspective illustration of a method of making
reinforcing ribbons that are deformed in a desired configuration
prior to being adhered to a paperboard base sheet.
[0035] FIG. 15 is a perspective illustration of one possible
configuration of impression cylinders for perforating paperboard
ribbons to provide enhanced adhesion prior to adhering the ribbons
to a base sheet.
[0036] FIG. 16 is a perspective illustration of another possible
configuration of impression cylinders for deforming paperboard
ribbons to form longitudinal flutes prior to adhering the ribbons
to a base sheet.
[0037] FIG. 17 is a perspective illustration of yet another
possible configuration of impression cylinders for deforming
paperboard ribbons to form lateral corrugations prior to adhering
the ribbons to a base sheet.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] As mentioned above, carton blanks may be provided in the
form of pre-glued knocked down sleeves or completely flat sheets
depending upon the type of packaging operation in which they are to
be used. The carton blank shown in FIG. 3 is of the former type and
typically is partially folded and glued at the carton manufacturing
location and shipped to a packager in the form of a knocked down
sleeve. This sleeve, then, is erected by the packaging machinery
into an open-ended carton into which product is inserted before the
carton is sealed shut. This type of carton typically is used in
most beer and soft drink bottling plants. The carton shown in FIG.
8, on the other hand, typically is formed from a carton blank that
is shipped completely flat, folded around product in the packaging
machine, and glued shut. This latter type of carton blank is
different than the former in that the gluing of the carton to form
a sleeve is done at the product production and/or packaging
facility rather than at the carton fabricating facility. The
present invention will be described for the most part in terms of
making a flat carton blank typified by the carton of FIG. 8.
However, it should be understood that the invention is not limited
to the fabrication of flat carton blanks, but also includes the
fabrication of pre-glued knocked down carton sleeve blanks as well
as other types of carton blanks.
[0039] Referring now in more detail to the drawings, wherein like
numerals refer, where appropriate, to like parts throughout the
several views, FIG. 1 illustrates a fabrication line 11 for making
reinforced paperboard carton blanks according to a preferred
embodiment of the invention. The various stations along the
fabrication line 11 are illustrated in simplified functional form
for clarity of description. It will be understood, however, that
the fabrication line and the machinery making up the various
stations therealong are standard machinery in the paperboard making
industry and are well known by those of skill in the art. Further,
a detailed description of the machinery that makes up the
fabrication line is not necessary to a complete disclosure and
understanding of the invention. Accordingly, this machinery is not
described in detail here.
[0040] The fabrication line 11 in FIG. 1 has an upstream end 12 and
a downstream end 13 and the various elements used in the making of
paperboard blanks according to the invention flow along paths in a
direction extending generally from the upstream end toward the
downstream end of the line. A large roll 14 of a paperboard web 17
is rotatably mounted on a pair of mandrels 16 located at the
upstream end of the fabrication line 11. In carrying out the method
of the invention, the paperboard web 17, which is pre-cut to a
required width as described above, is drawn from the roll 17 and
advanced along a path, generally indicated by arrows 15, that
extends past the various stations of the fabrication line. In one
embodiment, the paperboard web 17 may be preprinted on one side, as
indicated at 23, with indicia such as application specific
graphics, trademarks, and logos; however, such preprinting is not
desired is some applications and should not be considered a
requirement or limitation of the invention. Alternatively, the web
may be printed on both sides, which is desirable for some
applications.
[0041] Mandrels 18, three of which are illustrated in FIG. 1, are
disposed at spaced locations along the path 15 adjacent the
upstream end 12 of the fabrication line 11. Ribbons 21 of
reinforcing material, each having a width less than the width of
the paperboard web 17, are rolled onto relatively narrow rolls 19
and the rolls 19 are rotatably mounted on the mandrels 18. The
ribbons 21 of reinforcing material are progressively drawn from the
rolls 19 along with the web 17 and initially are disposed atop and
move along the path 15 with the web 17. Each of the mandrels 18 may
carry multiple rolls 19 of ribbons 21 and each of the rolls 19 may
be positioned at any desired location across the width of the
mandrel. Further, each of the ribbons 21 of reinforcing material
may be cut to any desired width less than the width of the
paperboard web 17.
[0042] As the web 17 and ribbons 21 are drawn from their respective
rolls and advance along the path 15, the ribbons are positioned,
according to the locations of their rolls 19 on mandrels 18, at
predetermined locations across the width of the web 17. In the
configuration illustrated in FIG. 1, for example, the rolls 19 are
positioned such that a double layer of ribbons 21 is located
adjacent each of the opposed edge portions of the web, a single
ribbon is located in the central portion of the web, and a pair of
relatively narrow ribbons are disposed on either side of the
centrally located ribbon. By appropriately positioning the rolls 19
on the mandrels 18, virtually any placement and configuration of
ribbons 21 of reinforcing material may be obtained, as described in
more detail below.
[0043] The reinforcing material from which the ribbons 21 are
formed may be any of a variety of appropriate materials such as,
for example, thin plastic, fiberglass, woven or non-woven webs, or
foam, and these and other materials are considered to be within the
scope of the invention. Preferably, however, the ribbons also are
made of paperboard and most preferably are cut or slit from
paperboard trim or cull that otherwise has little or no commercial
value. The invention will be described hereinafter in terms of
ribbons of paperboard reinforcing material for ease and clarity of
understanding. It should be understood, however, that the term
"paperboard" when used in this context is intended to encompass and
include any material with the physical and mechanical attributes
necessary to provide the requisite reinforcing properties.
[0044] As the paperboard web 17 and ribbons 21 advance along the
path 15, they move through a traditional de-curling station 22,
where the paperboard of the web and ribbons is flattened and any
curl that may have been induced by rolling the paperboard onto
rolls 14 and 19 is removed. From the decurling station 22, the web
and ribbons advance further along the path 15 to a scoring station
24, which includes a pair of rollers 25 along which one or more
scoring wheels 26 are disposed. The scoring wheels 26 are
selectively positioned across the width of the rollers 25 to score
the web 17 with longitudinally extending fold lines 27, along which
carton blanks made by the method of the invention ultimately will
be folded when converted into cartons.
[0045] As described in more detail below, some of the fold lines 27
may be located adjacent or along an edge of a reinforcing ribbon
21. In such cases, these fold lines preferably are carefully
located a predetermined short distance from the edge of the ribbon
so that the ribbon will not adversely affect or interfere with the
folding of the paperboard along the fold lines. Alternatively, it
may be desirable to locate some fold lines in regions of the carton
blank where reinforcing ribbons are positioned so that the ribbons
and base sheet are folded when the carton is erected. In these
cases, it is likely that fold lines will transition from the
thinner or lower caliper base sheet to the thicker or higher
caliper reinforced regions. A method and apparatus for forming such
transitioned fold lines in such a way that they do not cause
cracking or otherwise interfere with the folding of the carton is
described in more detail below. In FIG. 1, however, the scoring
wheels 26 are located to provide substantially equally spaced fold
lines across the width of the paperboard web 17. It will be
understood, however, that any number of fold lines at any number of
locations across the web, or no fold lines, as determined by the
desired final shape and size of cartons being made, are possible
and within the scope of the invention.
[0046] With the fold lines 27 scored in the paperboard web 17, the
web 17 advances along the path 15 to a pair of guide rollers 31 and
the paperboard reinforcing ribbons 21 diverge from the web 17 and
advance to a gluing station 28 for receiving adhesive. In the
illustrated embodiment, the gluing station 28 comprises an array of
traditional adhesive applicators 29, each having a pair of nip
rollers 32 between which one or more paperboard reinforcing ribbons
pass. The lower nip roller 32 of each of the applicators 29 is
partially immersed in an appropriate liquid adhesive contained
within a flooded nip bath 33. As the paperboard reinforcing ribbons
21 pass between the nip rollers, a layer of adhesive is transferred
from the lower nip roller of each pair to the bottom side (as seen
in FIG. 1) of each ribbon 21. An array of three adhesive
applicators 29 are illustrated in FIG. 1 for applying adhesive to
the seven paperboard reinforcing ribbons in the illustrated
embodiment. Fewer or more than three adhesive applicators 29 may be
used as necessary depending upon the number and configuration of
reinforcing ribbons required in a particular application.
[0047] Means other than nip rollers and nip baths for applying
adhesive to the ribbons may be used to apply adhesive to the
ribbons. Such alternative means include adhesive sprays, which
commonly are used in the paperboard industry. Adhesive spraying
mechanisms for use in the paperboard industry are commercially
available and may be obtained, for example, from the Nordson
Company. In any case, i.e. whether applied with nip rollers,
sprayers, or otherwise, adhesive may be applied to the reinforcing
ribbons 21 in a continuous coat, a discontinuous coat, a
stitch-glued pattern, a strand, or otherwise. Preferably, the
adhesive is applied in such a way as to minimize the amount of
adhesive required to provide adequate paperboard-to-paperboard
bonding. In one embodiment of the present invention, adhesive is
applied along only one side of one or more of the ribbons to
produce a finished carton having inwardly foldable internal
structures such as separators and stiffeners, as described in more
detail below.
[0048] The paperboard web 17 advances from the guide rollers to the
compression station 34, which includes a pair main compression
rollers 36, that also may function as pull rollers. Likewise, the
adhesive bearing paperboard ribbons 21 advance from the gluing
station 28 toward the compression station 34 and toward the
paperboard web 17. At the compression station 34, the paperboard
ribbons 21 and paperboard web 17 pass between the main compression
rollers 36. The compression rollers 36 are set to compress the
reinforcing ribbons 21 and the web 17 together with sufficient
pressure to bond the adhesive and thus the ribbons to the web, or
to other underlying ribbons in cases where multiple laminations of
ribbons are to be applied to the web 17. In this way, the ribbons
are progressively applied to the advancing web of paperboard at
selected locations across the width of the web, as determined by
the placement of rolls 19 on mandrels 18.
[0049] From the compression station 34, the paperboard web 17,
possibly with scored fold lines 27, and with the paperboard
reinforcing ribbons 21 laminated thereto proceeds toward the
downstream end 13 of the fabrication line 11 and toward a cutting
station 37. In the illustrated embodiment, the cutting station 37
includes a traditional rotary knife assembly 38, which rotates to
cut the web 17 across its width into rectangular sheets of a
predetermined size. Each sheet has a width equal to the width of
the paperboard web 17 and a length determined by the settings and
operation of the rotary knife assembly 38. Means other than a
rotary knife such as, for example, a traversing knife assembly or a
platen cutter may be substituted for the rotary knife of the
illustrated embodiment and these and other means for cutting the
web should be considered equivalent to the illustrated rotary knife
assembly.
[0050] Once the web 17 is cut into sheets 39, the sheets may be
stacked and delivered to a die cutter, where the sheets are cut and
scored in a standard platen die-cutting operation to form carton
blanks having the various foldable tabs and panels necessary to
form paperboard cartons embodying principles and features of the
invention.
[0051] As an alternative to cutting the web 17 into sheets 39 and
subsequently die-cutting the sheets 39 to form paperboard blanks,
the rotary knife assembly 33 in FIG. 1 may be replaced with a
platen die cutter or rotary inline die cutter, in which case the
web 17 is cut and scored immediately into carton blanks at the
downstream end of the fabrication line 11 and the step of first
cutting the web into sheets is eliminated. In either case, once the
carton blanks are cut and scored, they may be palletized and
shipped to product packagers, where the blanks are converted into
cartons and packed with articles in the usual way.
[0052] When the blanks are converted, the ribbons of reinforcing
paperboard laminated to the carton blanks form multiple layers of
paperboard in selected portions of the cartons and thus reinforce
the cartons in these portions. The locations of the ribbons are
carefully determined in advance such that, when the carton blank is
converted to a carton, the ribbons and thus reinforcement is
provided in selected portions of the cartons such as, for example,
in their side walls, where added strength and/or rigidity are
required. In one embodiment, discussed in more detail below, some
of the reinforcing ribbons may span the locations of folds, in
which case the ribbon and base sheet are scored along the fold
lines. When thus folded, the reinforcing ribbon is formed into an
L-shape, which provides a post-like corner that can enhance greatly
the structural integrity and load bearing capacity of the carton.
In fact, it has been discovered empirically that such posts, when
judicially positioned, can provide up to 75 percent or more of the
load bearing capacity of an erected carton. In any case, reinforced
paperboard cartons made by the method of this invention have been
found to exhibit strength and rigidity in the reinforced portions
that is comparable or superior to that of cartons made from
micro-flute.
[0053] With the forgoing specific example in mind, it will be
appreciated that, in one embodiment, the present invention is a
unique method of making reinforced paperboard cartons. The method
includes the steps of advancing a web of paperboard along a path,
the web of paperboard having a width. At least one ribbon of
reinforcing material having a width less than the width of the
paperboard web is progressively applied, preferably with adhesive,
to the advancing web at a predetermined position across its width.
The web with its applied reinforcing ribbon is cut to form carton
blanks and the carton blanks are formed into cartons for receiving
articles, the ribbon of reinforcing material providing
reinforcement in selected portions of the cartons where added
strength is required.
[0054] FIG. 2 is a cross-sectional view of the web 17 of FIG. 1 as
it appears after the reinforcing ribbons 21 have been bonded to the
web, such as just beyond the compression station 34. While this
particular configuration may or may not correspond to that of an
actual carton, it is presented along with FIG. 1 to illustrate
clearly some of the variety of possible sizes and placements of
reinforcing ribbons 21 and scored fold lines 27 that may be
obtained through the method of the invention. In FIG. 2, the
reinforcing ribbons 21 are applied at predetermined locations
across the width of the web 17 such that a double layer of ribbons
is disposed adjacent each edge portion of the web and a single
ribbon is located intermediate the edges of the web. A relatively
thin ribbon is located on either side of the centrally located
ribbon and the web is scored to form longitudinally extending fold
lines 27 spaced a short distance from the edges of some of the
reinforcing ribbons.
[0055] FIG. 3 illustrates one possible configuration of an actual
carton blank that may be formed by the method of the invention. The
carton blank 51 has a base sheet 55 of paperboard material, which
is a part of the continuous web of paperboard used to make the
blank 51 according to the invention. The base sheet 55 has
longitudinally extending fold lines 53, which, in this particular
example, may have been scored at a scoring station 24 of a
fabrication line 11 (FIG. 1) or during a die cutting operation, and
transversely extending fold lines 52, which may have been scored
during the die-cutting process. The fold lines 52 and 53 define a
top panel 54, a bottom panel 56, a first side panel 57, and side
panel tabs 58 and 59, which overlie one another when the carton
blank is converted to form a second side panel of the carton. End
tabs 61 are formed outboard of the longitudinally extending fold
lines 53 and the end tabs are configured to be folded inwardly
along the fold lines 53 when the blank is converted to form the
ends of the carton.
[0056] Paperboard reinforcing ribbons 62 are laminated to the base
sheet 55 according to the method of the invention. The reinforcing
ribbons 52 are positioned along and increase the effective
thickness of the end tabs 61 to reinforce the end tabs and provide
enhanced structural integrity in the end portions of a carton
converted from the blank. During conversion of the blank 51 into a
carton, the various panels and tabs of the blank are folded
generally inwardly along the scored fold lines 52 and 53 as
indicated by arrows 60, and selected ones of the tabs are secured
together with adhesive or otherwise to form a rectangular carton to
be packaged with articles. The carton, when formed, has ends
defined by the end tabs 61 that are reinforced by the paperboard
reinforcing ribbons 62 laminated thereto to provided enhanced
strength, rigidity, and tear or blow-out resistance in the ends of
the carton. Thus, when the blank 51 is converted, it forms a
reinforced paperboard carton having a plurality of panels defining
sides and ends of the carton and a layer of reinforcing paperboard
material applied to selected ones of the panels to reinforce the
carton in selected regions defined by the reinforced panels.
[0057] FIGS. 4 and 5 illustrate one possible placement of the
reinforcing paperboard ribbons 62 with respect to adjacent fold
lines 53 to insure in such an embodiment that the added thickness
of the ribbons does not interfere with the folding of the carton
blank along the fold lines during conversion. As mentioned above,
in other embodiments the fold lines may be located in regions where
laminated reinforcing ribbons are present and certain fold lines
may transition or cross the junction between a non-reinforced
region and a reinforced region. Such other embodiments are
discussed in more detail below. In the embodiment of FIGS. 4 and 5,
however, the paperboard base sheet 55 has a longitudinally
extending fold line 53 that defines an end tab 61 of the carton
blank. Reinforcing paperboard ribbon 62 is laminated to the base
sheet 55 in the region of the end tab 61 according to the present
invention to provide reinforcement as described above. The inboard
edge 65 of the ribbon 62 is spaced a predetermined short distance
from the fold line 53. Thus, when the sheet 55 is folded along fold
line 53 during conversion to a carton, as illustrated in FIG. 5,
the space between the edge 65 of the ribbon and the fold line
insures that the edge of the ribbon does not impact any of the
panels of the blank or otherwise interfere with the folding
process.
[0058] It has been found that a distance between a fold line and an
edge of a reinforcing ribbon of about the thickness of the
paperboard base sheet allows unimpeded folding of a carton blank
along the fold line. It also has been found that such a distance is
easily achieved and maintained when performing the method of this
invention with standard paperboard making machinery as illustrated
in FIG. 1. Of course, distances other that the preferred distance
may be chosen according to application specific requirements and
any appropriate distance is intended to be within the scope of the
invention. Further, in some applications, reinforcing ribbons may
be applied at locations on the paperboard web other than adjacent
to fold lines. In these cases, the distance between edges of the
ribbon and fold lines generally is not critical. Finally, as
mentioned briefly above, fold lines also may be formed in regions
where the base sheet is reinforced by reinforcing ribbons and
certain fold lines may transition between thinner base sheet only
regions and thicker reinforced regions.
[0059] FIGS. 6a through 6h are provided to illustrate some of the
many possible configurations in which reinforcing ribbons may be
applied to a paperboard web using the method of the present
invention. Each of these figures is a cross-sectional view of a web
with reinforcing ribbons applied thereto and longitudinally
extending fold lines are scored in some of the figures. It should
be understood that these figures do not necessarily represent
configurations corresponding to actual carton blanks, but instead
are generally simplified drawings selected for clarity in
describing some of the many possible configurations of reinforcing
ribbons. Also in this regard, the thickness of the paperboard web
and reinforcing ribbons generally is exaggerated in FIGS. 6a
through 6h for clarity of illustration.
[0060] In FIG. 6a, a the paperboard web forms a base sheet 66
having reinforcing paperboard ribbons 67 laminated thereto and
extending along the opposed edge portions of the base sheet. Fold
lines 68 are scored in the base sheet extending along and adjacent
to the inboard edges of the reinforcing ribbons 67 to facilitate
folding of the base sheet in the formation of a carton. A
configuration of reinforcing ribbons similar to that of FIG. 6a may
be selected, for example, when forming carton blanks such as the
blank 51 illustrated in FIG. 3.
[0061] FIG. 6b illustrates a possible configuration similar to that
of FIG. 6a but having a double thickness paperboard base sheet 69
formed from a first paperboard sheet 71 and a second paperboard
sheet 72 laminated together. Reinforcing ribbons 73 are applied
along the opposed edge portions of the base sheet 69 and fold lines
74 are scored in the base sheet to facilitate folding. Referring to
FIG. 1, a configuration similar to that of FIG. 6b may be made by
the method of the invention by, for example, mounting a second roll
of full width paperboard on the mandrel 18 immediately upstream of
the mandrel 16. Alternatively, a roll of double thickness laminated
web may be made in advance in a separate process and mounted on
mandrel 16.
[0062] FIG. 6c illustrates the possibility of applying multiple
laminations of reinforcing ribbons, one atop the other, to provide
even more reinforcement in areas where further enhanced structural
integrity may be required. In this figure, three stacked
reinforcing ribbons 78 are applied along the opposed edge portions
of a base sheet 76, to form multiply laminated reinforcing ribbons
77. Such a configuration may be formed by the method illustrated in
FIG. 1 by aligning rolls 19 of reinforcing ribbons with each other
on successive mandrels 18 so that the reinforcing ribbons overlie
one another as they are drawn from their respective rolls.
Alternatively, rolls of multi-ply pre-laminated reinforcing ribbons
may be made in advance and mounted on mandrels 18 if desired to
obtain similar results.
[0063] FIG. 6d illustrates the ability to apply multiple
reinforcing ribbons at selected locations across the width of a
paperboard web using the method of the invention. Here, three
reinforcing ribbons 81 are applied to a paperboard base sheet 82,
two along the opposed edge portions of the base sheet and one
intermediate the edge portions. While the reinforcing ribbons 81 in
FIG. 6d are illustrated with substantially the same width, it will
be understood that each ribbon may have a different width and may
be positioned at any desired location across the width of the base
sheet according to a desired configuration and reinforcement
requirements of a finished paperboard carton. Selective placement
of the reinforcing ribbons is achieved in the method illustrated in
FIG. 1 by selectively positioning the rolls 19 of reinforcing
ribbon across the width of mandrels 18.
[0064] FIG. 6e illustrates the possibility of applying selectively
positioned multi-layer reinforcing ribbons to a paperboard base
sheet. Multiple layers of reinforcing ribbons 84 are applied atop
each other on a base sheet 82 to form reinforcing ribbons 83, one
extending along each of the opposed edge portions of the base sheet
and one positioned intermediate the edge portions. Of course, any
number of ribbons 83 may be applied, each of the ribbons 84 and
resulting strips 83 may be any desired width, and the ribbons may
be applied at any desired location across the width of the base
sheet 82.
[0065] FIG. 6f shows the possibility of applying multiple
reinforcing ribbons formed of multi-layer reinforcing ribbons at
selected positions intermediate the edge portions of a base sheet.
Multiple reinforcing ribbons 87 each formed of multiple layers of
reinforcing ribbons 88 are applied to the base sheet at selected
locations on the base sheet 86 not extending along the edge
portions thereof.
[0066] FIG. 6g illustrates a configuration possible with the method
of the invention wherein one or more reinforcing ribbons 91 applied
to a base sheet 89 is formed of multiple layers of reinforcing
ribbons 92 and 93 the reinforcing ribbon 93 having a width less
than the width of reinforcing ribbon 92. Any number of layers of
ribbons may be applied in this manner to form multi-layer
reinforcing ribbons with each ribbon of the strips having a width
different from the widths of the other ribbons of the strips,
according to application specific requirements. A relatively
narrower reinforcing ribbon 94 is applied in FIG. 6g to the base
sheet 89 at a selected location intermediate its edges. Thus,
multiple reinforcing ribbons each having different widths may be
applied at any desired location across the width of the base sheet
through the method of the present invention.
[0067] FIG. 6h illustrates a unique application of the method of
this invention to form internal structures of a carton such as, for
example, L-brackets, stiffeners, and separators. A ribbon 97 is
applied to a base sheet 96 according to the method of the
invention. In this case, however, the method includes applying
adhesive along only one side of the ribbon before bonding the
ribbon to the paperboard web. The ribbon 97 has a fold line 101
scored therein and the fold line separates the ribbon into a first
section 98 and a second section 99. Adhesive is applied to the
first section 98, which is bonded to the base sheet 96, and the
second section 99 is free to be folded along fold line 101 as
indicated by arrow 102 to project in a direction away from the base
sheet 96.
[0068] The fold line 101 in the ribbon 97 may be scored at the
scoring station 24 (FIG. 1) or, alternatively, the ribbon may be
pre-scored prior to winding it onto a roll 19. Alternatively, the
fold line may be formed during a platen or rotary in-line die
cutting process. In any case, the second portion 99 of the ribbon
functions in the final carton as an internally extending structure.
Methods of providing adhesive to only a portion of the ribbon 97 as
illustrated in FIG. 6h are known in the paperboard industry and may
include, for example, masking techniques and/or spraying the
adhesive onto the selected portion ribbon as it advances along the
fabrication line 11 (FIG. 1).
[0069] FIG. 7 illustrates one of the many possible configurations
of cartons that may be made by the method of the present invention.
The carton 106, which may, for example, be a shipping and display
container for food items such as candy bars, is converted from a
carton blank made according to the invention and has front and back
walls 107, end walls 108, and a floor 110. The front and back walls
107 are structurally reinforced with paperboard reinforcing ribbons
109 applied to the insides of the panels that form the walls 107.
Thus, the front and back walls 107 of the carton 106 exhibit
enhanced strength and rigidity as a result of the reinforcing
ribbons. These properties may be desirable, for example, to enhance
the stackability of the cartons when packaged with product, to
resist blow-out during shipment, or to provide resistance to
tearing in the corners or other high stress locations of the
carton.
[0070] Further according to the invention, the reinforcing ribbon
109 on the back wall 107 of the carton 106 is seen to have been
pre-printed with indicia that is visible on the inside of the
carton. Thus, the method of this invention may eliminate the
requirement of double sided printing on a carton base sheet when it
is desired to display indicia on the inside of a carton. In FIG. 7,
the indicia 101 is illustrated as a savings coupon; however, any
form of indicia such as, for example, instructions, contests rules,
special graphics, or otherwise may be provided. Further, because
the reinforcing ribbon is pre-printed, it may be provided with a
coated or primed printing surface, which allows high-quality
graphics to be printed on the reinforcing ribbon. This is an
economical improvement over previous internal printing, which, as
mentioned above, has been somewhat limited in available printing
quality.
[0071] In addition or as an alternative to the printing of indicia,
reinforcing ribbons may be pre-coated if desired with a moisture
resistant or other type of coating. In such cases, the method of
this invention may be used to make efficiently produced lined
cartons for use as alternatives to cartons such a detergent boxes,
which traditionally have been supplied with separate individually
inserted moisture resistant liners.
[0072] FIG. 8 illustrates another configuration of a reinforced
paperboard carton made according to the method of the invention.
The end of the carton is shown in cross-section to illustrate
better the internal structural components of the carton. The carton
116, which is illustrated as a carton for packaging fruit drink, is
generally rectangular in shape and is folded along fold lines 125
to define side walls 117, a bottom wall 118 and a top wall 119. The
top wall 119 is formed by overlapping flaps 120 and 121, which may
be secured together by any appropriate means such as with adhesive,
and may be provided with a cut-out 122 if desired to form a
carrying handle. The side walls 117 have outside surfaces formed by
respective panels 124. Reinforcing ribbons 123, which preferably
also are made of paperboard, are applied to the side wall panels
124 on the inside of the carton according the invention and form
the inside surfaces of the side walls 117. As previously discussed,
the reinforcing ribbons 123 enhance the structural integrity of the
side walls 117 to provide increased strength and rigidity in the
sides of the carton for stackability and resistance to carton
blow-out. At least one of the reinforcing ribbons 123 is seen to be
printed with indicia 127 that is exposed on the inside of the
carton and that may become apparent to a consumer as product is
removed from the carton.
[0073] Paperboard dividers and stiffeners 126 are applied as
described above relative to FIG. 6h to the bottom wall 118 and the
top wall 119 on the inside of the carton 116. Each of the dividers
and stiffeners is formed from a ribbon of paperboard applied
according to the method of the invention and has a first portion
129 bonded to the respective wall and a second portion or flap 128
that is folded to extend internally into the carton. The flaps 128
may function to provide structural stiffness to the top and bottom
walls and/or to provide spacers or protective separators for
articles to be packaged in the carton. Indeed, a wide variety of
internal carton structures previously provided by separate and
expensive inserts may be made economically, efficiently, and
virtually automatically using the method of the present
invention.
[0074] FIGS. 9 through 13 illustrate a carton blank and scoring
methodology that embody principles of the invention in another
preferred form. More specifically, the embodiment of these figures
includes a carton blank with longitudinal fold lines that are
scored within regions reinforced by reinforcing ribbons rather than
being located closely adjacent the edges of the ribbons, such as in
FIGS. 4 and 5. Further, this embodiment includes transverse fold
lines that transition from the thinner or lower caliper base sheet
of the blank to the thicker laminated regions where reinforcing
ribbons are applied. In other words, some fold lines cross the
edges of laminated reinforcing ribbons. As is known by those of
skill in the art, fold lines in thinner material must be narrower
than fold lines in thicker material. For example, for a standard 26
point paperboard (0.026 inches thick), the appropriate fold line
for producing a sharp structurally sound fold without cracking the
outer coating of the paperboard typically is impressed with a 3 to
4 point scoring rule (i.e. a rule that is from 0.003 to 0.004
inches thick) in a platen or in-line rotary die cutter. However, to
produce an acceptable fold in thicker 44 point paperboard material,
a 6 point rule is advisable for scoring the fold line. To use a
thinner rule with this thicker material results in cracking and
damage to the paperboard when it is folded along the fold line.
Conversely, to use, for example, a 6 point rule to produce fold
lines in, for instance, a thinner 26 point paperboard results in
folds that are too rounded and lack the crisp appearance and
structural integrity required in the final carton.
[0075] The forgoing physical limitations and requirements give rise
to problems in laminated ribbon reinforced carton blanks made
according the present invention when fold lines are required to
transition from a region of the blank formed only of thinner base
sheet material and a region that is thicker because it is
reinforced with laminated ribbons. More particularly, heretofore
there have been no known methods of forming a continuous fold line
with platen or rotary die cutters that is thicker along one section
of its length (the section that is to score a fold line in the
thicker ribbon reinforced region of the blank) and thinner along an
adjacent section (the section that is to score a fold line in the
thinner base-sheet-only region of the blank). Furthermore, even if
such a multi-point fold line could have been formed, the margin of
error of up to one-eighth of an inch in positioning reinforcing
ribbons with some machinery would result in a portion of the
thinner fold line sometimes extending into the thicker laminated
region or vice versa. Such a condition is unacceptable because it
results in tearing, cracking, and other damage at the location of
the edge of the reinforcing ribbon when the carton blank is folded
to form a carton.
[0076] The carton blank and fabrication technology illustrated in
FIGS. 9 through 13 represent a unique method of making a
multi-point or varying width continuous rule in a die cutter head
for forming a continuous fold line that is thicker along one
section of its length where thicker paperboard is to be scored and
thinner along an adjacent section where thinner paperboard is to be
scored. An equally unique methodology for transitioning between the
two regions is disclosed that produces fold lines which allow for
typical margins of error in positioning reinforcing ribbons. These
discoveries and inventions are discussed in detail in the
immediately following portion of this disclosure.
[0077] Referring to FIG. 9, a laminated reinforced carton blank 151
has a paperboard base sheet 152, to the edges of which upper and
lower ribbons of reinforcing material 153 and 154 are laminated
according to the forgoing discussions. The blank 151 generally is
shown as it appears after having been cut and scored in a platen or
rotary die cutter. More specifically, the blank is cut along its
top edge to form end flaps 156 and 157, and end tabs 159 and 159.
Similarly, the blank 151 is cut along its bottom edge to form end
flaps 161 and 162, and end tabs 163 and 164. These flaps and tabs
form the closed ends of a finished carton formed from the blank
151, as is known in the art. It will be understood that in FIG. 9,
the complete outlines of the reinforcing ribbons 153 and 154 are
shown for clarity of discussion and understanding; however, in
reality the end flaps are cut completely through the reinforcing
ribbons and the underlying base sheet.
[0078] Transverse fold lines 168 are scored generally across the
blank and these fold lines define the various panels 172 of the
blank, which ultimately will become the sides of the finished
carton. Longitudinal fold lines 169 and 171 are scored along the
blank 151 adjacent the end flaps and end tabs to allow for the
folding up of the flaps and tabs in forming a carton. Regarding the
longitudinal fold lines, it will be seen that they are located
within the regions of the blank 151 that are reinforced by the
reinforcing ribbons 153 and 154 rather than along the edges of
reinforcing ribbons as in the embodiment of FIGS. 4 and 5. The
transverse fold lines 168 intersect at their ends with the
longitudinal fold lines 169 and 171. Accordingly, the transverse
fold lines transition across the edges of the reinforcing ribbons
153 and 154 at positions referred to herein as transition zones
173.
[0079] As discussed above, fold lines and portions of fold lines
located in non-reinforced regions of the blank 151 where the total
material thickness is equal to the thickness of the base sheet are
thinner than fold lines and portions of fold lines located in
thicker reinforced regions, where the total thickness is the sum of
the thickness of the base sheet and the thickness of the
reinforcing ribbons. For example, with a standard 26 point base
sheet with 18 point reinforcing ribbons (total thickness of 44
points in the reinforced regions), fold lines located only in the
base sheet typically are formed with a narrower 3 or 4 point rule
while fold lines in reinforced regions may be formed with a wider 6
point rule. Thus, a transition from a narrower fold line to a wider
fold line occurs at the transition zones 173. These transition
zones, the configuration and formation of which is discussed in
more detail below, must be formed so as to allow for the margin of
error in locating the reinforcing ribbons without causing cracking
and paperboard damage when the carton blank is folded along
transverse fold lines 168.
[0080] FIG. 10 is an enlarged illustration of a section of the
carton blank of FIG. 9 showing more clearly a transition zone 173
where a fold line 168 crosses the edge 160 of a reinforcing ribbon
153. Longitudinal fold line 169, which extends along the ribbon
153, is shown intersecting transverse fold line 168 at its end. As
is more clearly seen in this figure, the fold lines and portions of
fold lines in thicker regions of the blank where the laminated
reinforcing ribbon 153 is located are wider than fold lines and
portions of fold lines in thinner regions where there is only base
sheet material. Within the transition zone 173, the width of the
fold line 168 is seen to increase gradually and smoothly from its
narrower to its wider dimension. In practice, it has been found
that a preferred length of the transition zone, i.e. the distance
from the end of the narrower section of the fold line to the
beginning of the wider section, is about one-eighth of an inch
(0.125 inches). It has been discovered that so long as the edge of
the reinforcing ribbon falls within the gradually widening
transition zone of the fold line, cracking and damage at the
position of the edge of the reinforcing ribbon when the blank is
folded along the fold line is eliminated. Most preferably, the
reinforcing ribbon is positioned so that its edge falls nearer the
wider end of the of the transition zone. However, even when margins
of error in positioning reinforcing ribbons locates an edge of a
ribbon nearer the narrow end but still within the transition zone,
damage and cracking at this location when the blank is folded along
the fold line still is eliminated.
[0081] A one-eight inch long transition zone is selected in the
preferred embodiment because well maintained paperboard making
machinery should be able to position the reinforcing ribbons with a
margin error of less that one-sixteenth of an inch, insuring that
the edges of the ribbons always fall within a transition zone. Even
older or poorly maintained machinery should be able to maintain a
margin of error of less that one-eight of an inch, insuring in all
cases that the edge of the reinforcing ribbons cross fold lines
within transition zones. Nevertheless, transition zones may well be
configured to be less than or more than one-eighth of an inch long
according to application specific constraints. Thus, a one-eight
inch long transition zone should not be considered to be a
limitation of the invention disclosed and claimed herein.
[0082] FIG. 11 illustrates a rule and counter plate configuration
in a platen die cutter for forming the transitioned fold lines
shown in FIGS. 9 and 10. As is known by those of skill in the art,
a platen die cutter generally includes a rigid metal table or bed
and a head movable toward and away from the bed. Embedded within
and projecting a short distance downwardly from the head are thin
metal knives and thin metal blades forming a scoring rule. A
relatively thin counter plate is located on the bed and the counter
plate is formed with grooves aligned with the scoring rule. In use,
a paperboard blank is positioned on the bed and the head is pressed
with considerable force against the blank and the bed. As a result,
the knives of the head cut through the blank to form the outline of
the cut carton blank, i.e. to form the various flaps and tabs of
the blank. At the same time, the blades of the scoring rule and
aligned grooves in the counter plate compress the paperboard along
their lengths to form the various fold lines in the blank (See FIG.
9). The same general principal applies to in-line rotary dies. The
general construction and operation of platen and in-line rotary die
cutters is understood by those of skill in the art and thus need
not be discussed in more detail here, except with respect to the
configuration of a multi-point rule and corresponding counter plate
configurations for forming transitioned fold lines according to the
invention.
[0083] With the forgoing in mind, FIG. 11 illustrates a rule 177
projecting downwardly from the head (not shown) of a platen die
cutter toward the metal bed 183 of the cutter. An intersecting rule
180 is also illustrated. A portion of the counter plate 182 of the
platen die cutter is shown formed with grooves 184 that are aligned
with the rule sections 177 and 180. In use, a paperboard blank is
inserted atop the bed and the counter plate and the head is brought
down with pressure atop the blank. The rule 177 and 180 engages and
compresses the blank along their blades and deforms the blank
slightly into the grooves 184, thereby forming fold lines in the
blank, generally in the traditional way. However, the combination
of elements shown in FIG. 11 is unique in that these elements are
configured to form the transitioned fold lines of the present
invention. More specifically, the rule 177 is made up of a thinner
or lower point rule section 178 for scoring thinner material of the
blank and a wider or higher point rule section 179 for scoring
adjacent thicker material of the blank. The rule sections 178 and
179 abut one another at butt joint 181, thus forming a continuously
extending multi-point rule 177.
[0084] The portion of the groove 184 in the counter plate 182 that
is aligned with and underlies the lower point rule section 178 has
a width that is appropriate for complementing the thickness of the
rule section 178 when scoring fold lines. Similarly, the portion of
the groove 184 that is aligned with and underlies the higher point
rule section 179 has a width that complements the thickness of the
rule section 179 when scoring fold lines. A transition region 186
of the groove 184 generally underlies the butt joint 181 of the
rule 177. The transition region 186 is seen to be formed with a
gradually and smoothly increasing width that transitions from the
narrow portion of the groove 184 to the wider portion of the
groove. In practice, as discussed above, the length of the
gradually widening transition region 186 preferably is about
one-eighth of an inch. The butt joint 181 preferably is aligned
near or at the wider portion of the transition region 186. With
such a configuration, a fold line with a transition zone of about
one-eight of an inch in length is formed in a paperboard blank, as
discussed above relative to FIG. 10.
[0085] FIG. 12 illustrates a section of a reinforced carton blank
after having been cut and scored with fold lines according to
principles of the present invention. The sizes of the fold lines in
this figure are somewhat exaggerated for clarity of discussion. As
in FIG. 9, the blank 151 has a paperboard base sheet 152 and a
reinforcing ribbon 153 is laminated to the base sheet along its
outside edge. A longitudinal fold line 169 is formed along the
reinforcing ribbon and a transverse fold line 168 intersects at its
end with the longitudinal fold line 169. The fold lines define
panels 172, flaps 157, and tabs 159, as discussed above relative to
FIG. 9. The transverse fold line 168 crosses the edge of the
reinforcing ribbon 153 at transition zone 173 and, according to the
invention, transitions the fold line 168 from its narrower width in
the base-sheet-only region of the blank to its wider width within
the reinforced region of the blank. Arrows 191, 192, and 193
indicate the folding of the blank 151 along its fold lines in the
formation of a carton from the blank. As discussed above, the
location and configuration of the transition zone 173 insures
against damage and cracking at the location of the intersection of
the fold line 168 with the edge of the reinforcing ribbon when the
blank is folded along the fold line 168, as indicated by arrow
191.
[0086] FIG. 13 is a longitudinally sectioned view through the rule
177 of FIG. 11 looking downwardly toward the bed of platen die
cutter. As discussed above, the rule 177 is formed with a
relatively thinner rule section 178 and a relatively wider rule
section 179 butted at butt joint 181. Counter plate 182 underlies
the rule 177 and is formed with an aligned groove 184. The portion
of the groove 184 underlying the narrower rule section 178 is
narrower than the portion of the groove underlying the wider rule
section 179. A smoothly contoured transition zone 186 transitions
between the narrower and wider portions of the groove 184. The
transition zone 186 has a length X from the end of the narrower
portion of the groove to the beginning of the wider portion. As
discussed above, for forming the ribbon reinforced carton blanks of
the present invention, X preferably is about one-eighth of an inch;
however, other lengths may be used depending upon particular
application specific constraints. A preferred positioning of an
edge 195 of a reinforcing ribbon relative to the rule and groove is
illustrated in phantom lines. Specifically, the ribbon preferably
is positioned on a base sheet such that its edge 195 crosses the
groove 184 nearer the wider end of the transition zone. However, it
has been found that so long as the edge falls generally within the
transition zone, cracking and carton damage upon folding is
virtually eliminated. Therefore, the transition zone of the present
invention allows for typical margins of error in positioning
reinforcing ribbons, as discussed above.
[0087] FIGS. 14 through 17 illustrate yet another embodiment of the
invention wherein ribbons of reinforcing material may be deformed
or altered for a particular purpose prior to being adhered to a
paperboard base sheet. Referring to FIG. 14, a fabrication line 196
has an upstream end 197 and a downstream end 198. A roll 199 of
paperboard base sheet is rotatably disposed on a mandrel 200 at the
upstream end 197 of the fabrication line. A web 203 of paperboard
base sheet is drawn progressively from the roll 199 and moves
generally in a downstream direction along a path 201. A roll 206 of
paperboard reinforcing material is rotatably mounted on a mandrel
207, also located at the upstream end 197 of the fabrication line.
A web 208 of reinforcing material is drawn from the roll 206 and
moves in a downstream direction generally along the direction of
the path 201. A slitting station 209 is disposed downstream of the
global roll 206 of reinforcing material and includes a shaft 212 to
which a plurality of slitting wheels are mounted. As the web 208 of
reinforcing material moves past the slitting section, it is cut or
slit to form individual reinforcing ribbons 213, which are spread
out by a spreader (not shown) to move along separate selectively
positioned paths.
[0088] As the reinforcing ribbons 213 move further downstream, they
pass between a pair of mated impression cylinders 214. The
impression cylinders 214 have mating surfaces that are formed with
a predetermined pattern so that the reinforcing ribbons 213 are
deformed, altered, or embossed as the case may be into the pattern
formed in the impression cylinders 214. In the illustration of FIG.
14, the impression cylinders are formed with intermeshing
longitudinally extending teeth or ribs, which deform the
reinforcing ribbons to exhibit laterally extending corrugations.
However, as discussed below, the ribbons can be deformed to exhibit
a wide variety of shapes and profiles according to application
specific requirements.
[0089] From the impression cylinders, the altered reinforcing
ribbons move downstream to a gluing station 217, which, in the
illustrated embodiment, includes a pair of nip rollers 218. The
lower nip roller 218 is partially submerged in a flooded nip bath
219 that contains an appropriate liquid adhesive. As the altered
reinforcing ribbons pass between the nip rollers, a coating of
adhesive is applied to the underside of the ribbons. Of course,
other types of adhesive applicators such as, for example, spray
applicators may be substituted for the nip roller arrangement of
FIG. 14.
[0090] From the gluing station 217, the adhesive bearing altered
reinforcing ribbons continue to move in a downstream direction
toward a compression station 221. At the same time, the web 203 of
base sheet material passes under an idler roller 202 and is
redirected upwardly toward the compression station 221. Thus, both
the base sheet web and the reinforcing ribbons move together toward
the compression station. At the compression station, the base sheet
web and the reinforcing ribbons come together and pass between a
pair of compression rollers 221 and 222 where sufficient pressure
is applied to adhere the adhesive bearing altered reinforcing
ribbons to the base sheet. Thus, a ribbon reinforced paperboard
blank is formed as in other embodiments, but in this embodiment the
reinforcing ribbons are corrugated or otherwise deformed or altered
to serve a particular purpose. From the compression station, the
web may move to an in-line rotary die cutter, a sheet cutter, a
platen die cutter, or otherwise to cut and form the web into carton
blanks as described above.
[0091] FIGS. 15 through 17 illustrate three possible configurations
of impression cylinders usable in the fabrication line of FIG. 14
to deform or alter the reinforcing ribbons before they are applied
to the base sheet to form reinforcing ribbons. In some instances,
it may be desirable to perforate the reinforcing ribbons with an
array of perforations. For instance, where superior adhesive
bonding of the ribbons to a base sheet is required, perforations in
the ribbons allow the adhesive to flow through the perforations to
form an interlocking bond between the reinforcing ribbons and the
adhesive layer. To obtain such perforations, impression cylinders
214 may be provided with arrays of spikes or punches. As the
reinforcing ribbons 213 pass between the impression cylinders, the
spikes or punches penetrate the ribbons and form an array of
perforations 224 therein. The perforated ribbons then proceed to
the gluing station and the compression station, where they are
adhered to the base sheet to form laminated reinforced carton
blanks.
[0092] FIG. 16 illustrates another possible configuration of
impression cylinders for deforming the reinforcing ribbons prior to
their application to the base sheet. Here, the impression cylinders
214 have surfaces formed with a series of side-by-side
circumferentially extending fluting grooves with the grooves of the
top cylinder meshing with the grooves of the bottom cylinder. As
the reinforcing ribbons 213 pass between these impression
cylinders, they are deformed to exhibit an array of longitudinally
extending flutes. The fluted reinforcing ribbons them move
downstream where they are adhered to the base sheet to form ribbon
reinforced carton blanks.
[0093] Finally, FIG. 17 illustrates a pair of impression cylinders
214 for forming transverse corrugations in the reinforcing ribbons
as illustrated in the example of FIG. 14. Here, the surfaces of the
impression cylinders 214 are formed with an array of longitudinally
extending teeth 228 that mesh together when the cylinders rotate to
deform the reinforcing ribbons 213 to exhibit transverse
corrugations 229. As with the other embodiments, the corrugated
ribbons then pass downstream where they are adhered to the base
sheet to form ribbon reinforced carton blanks.
[0094] While three different examples of impression cylinders have
been illustrated above, it should be understood that a wide variety
of different impression cylinders may be fabricated to form an
equally wide variety of deformations or alterations to the
reinforcing ribbons before they are applied to the base sheet. For
example, patterns, designs, words, or other indicia may be embossed
into the ribbons as desired. Other patterns for enhancing the
strength and structural integrity of the ribbons such as, for
example, dimples or "egg crate" patterns may be formed to produce
exceedingly strong reinforcing ribbons. Accordingly, it will be
seen that the embodiments of FIGS. 14 through 16 are examples only.
The invention is intended and should be interpreted to encompass
any types of deformations or other alterations that might be made
to the reinforcing ribbons prior to adhering them to the base sheet
to produced enhanced ribbon reinforced carton blanks.
[0095] The invention has been described herein in terms of
preferred embodiments and methodologies, which represent the best
mode known to the inventors of carrying out the invention. It will
be understood by those of skill in the art, however, that many
additions, deletions, modifications, and substitutions of
equivalent elements not specifically included in the preferred
embodiments may be made without departing from the spirit and scope
of the invention as set forth in the claims.
* * * * *