U.S. patent number 3,754,456 [Application Number 05/147,469] was granted by the patent office on 1973-08-28 for blank constructions for hermetically sealed cartons and methods of forming same.
This patent grant is currently assigned to Reynolds Metals Company. Invention is credited to William P. Andrews, Vincent J. Serio, Jr..
United States Patent |
3,754,456 |
Andrews , et al. |
August 28, 1973 |
BLANK CONSTRUCTIONS FOR HERMETICALLY SEALED CARTONS AND METHODS OF
FORMING SAME
Abstract
Blank constructions for use in making hermetically sealed, lined
carton constructions formed continuously from strips of paperboard
stock and liner material. An improved side seam construction is
also disclosed wherein a paperboard-to-paperboard seal is obtained
when using a liner material at least the outer surface of which is
metal foil. The blank construction is formed by methods which
permit one end of the liner material to overhang the paperboard
stock material whereby covered side seams are provided which
prevent air or liquid leakage through the pores of the paperboard
stock. An R.F. induction heating method is disclosed for making
side seams on lined cartons.
Inventors: |
Andrews; William P. (Richmond,
VA), Serio, Jr.; Vincent J. (Henrico County, VA) |
Assignee: |
Reynolds Metals Company
(Richmond, VA)
|
Family
ID: |
22521687 |
Appl.
No.: |
05/147,469 |
Filed: |
May 27, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
876699 |
Nov 14, 1969 |
|
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Current U.S.
Class: |
493/274; 493/276;
219/769; 493/294 |
Current CPC
Class: |
B29C
65/1432 (20130101); B29C 66/4322 (20130101); B29C
66/72328 (20130101); B29C 65/3656 (20130101); B29C
65/3668 (20130101); B29C 66/1122 (20130101); B29C
66/72321 (20130101); B29C 65/4815 (20130101); B29C
65/368 (20130101); B31F 1/0029 (20130101); B29C
65/3644 (20130101); B31F 7/004 (20130101); B29C
66/83411 (20130101); B29C 65/54 (20130101); B29C
65/1464 (20130101); B29C 66/8181 (20130101); B29C
66/49 (20130101); B29C 66/4326 (20130101); B29C
53/36 (20130101); B29K 2711/123 (20130101); B29C
65/482 (20130101); B29L 2009/00 (20130101); B29L
2031/7162 (20130101); B29C 66/7234 (20130101); B29K
2705/02 (20130101) |
Current International
Class: |
B29C
65/00 (20060101); B29C 65/54 (20060101); B29C
65/14 (20060101); B31F 1/00 (20060101); B29C
65/02 (20060101); B29C 65/52 (20060101); B31F
7/00 (20060101); B29C 53/36 (20060101); B29C
53/00 (20060101); B31b 001/36 () |
Field of
Search: |
;93/49R,49M,36.01,36.6,41,46,52,DIG.1 ;219/10.53,10.49,10.61
;53/DIG.2,388,373,375,379 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Juhasz; Andrew R.
Assistant Examiner: Culver; Horace M.
Parent Case Text
This is a continuation-in-part of Ser. No. 876,699, filed Nov. 14,
1969, now abandoned.
Claims
What is claimed is:
1. A method of forming a side seam for a lined carton comprising
the steps of
1. forming a paperboard blank having a liner material adhesively
secured thereto, said liner material including a metallic foil
portion into which R.F. energy may be inductively coupled,
a. said paperboard blank having score lines thereon to define main
panels and a glue flap thereon hingedly secured to one of said main
panels with said glue flap having an unattached outer edge opposite
its hinged securement to one of said main panels.
b. said liner having an overhang portion which extends beyond the
unattached outer edge of said glue flap,
2.
2. feeding said paperboard blank continuously and while being fed
continuously, performing the following additional steps:
a. applying a first adhesive material to said glue flap,
b. folding said overhang portion of said liner through
approximately 180.degree. in order to secure said over-hang portion
to said first adhesive on said glue flap,
c. applying a second adhesive material to one of the following:
1. the exterior surface of the liner material in the region of said
glue flap,
2. the underside of the marginal edge of the main panel of said
carton blank most remote from said glue flap,
d. substantially completely folding said carton blank into
substantially tubular shape so as to bring said main panel of said
carton blank most remote from said glue falp to a position closely
adjacent said glue flap,
e. interposing an R.F. induction coil between said glue flap and
said closely positioned main panel and inductively heating said
metallic foil portion and, by contact with said metallic foil
portion, thereby activating said second adhesive material,
f. and, thereafter, pressing said glue flap and said main panel of
said carton blank most remote therefrom together to complete said
side seam.
A method of forming a side seam for a lined carton as claimed in
claim 1 including using an aqueous adhesive for said first adhesive
material and using a hot melt adhesive for said second adhesive
material.
3. A method of forming a side seam for a lined carton as claimed in
claim 1 including the step of feeding said carton blanks in
substantially a straight line throughout the formation of said side
seam.
4. A method of forming a side seam for a lined carton as claimed in
claim 1 including the step of feeding said blanks continuously at
linear speeds in excess of 400 feet per minute in the course of
forming said side seam.
5. A method of forming a side seam for a lined carton with the
liner thereof having an adhesive plastic coating on its exterior
surface, said method comprising the steps of:
1. forming a paperboard blank with said liner material adhesively
secured thereto, said liner material including a metallic foil
portion into which R.F. energy may be inductively coupled,
a. said paperboard blank having score lines thereon to define main
panels and a glue flap thereon hingedly secured to one of said main
panels with said glue flap having an unattached outer edge opposite
its hinged securement to one of said main panels,
b. said liner having an overhang portion which extends beyond the
unattached outer edge of said glue flap,
2. feeding said paperboard blank continuously and while being fed
continuously, forming the following additional steps:
a. applying a first adhesive material to said glue flap,
b. folding said overhang portion of said liner through
approximately 180.degree. in order to secure said overhang portion
to said first adhesive on said glue flap,
c. substantially completely folding said carton blank into
substantially tubular shape so as to bring said main panel of said
carton blank most remote from said glue flap to a position closely
adjacent said glue flap,
d. interposing an R.F. induction coil between said glue flap and
said closely positioned main panel and inductively heating said
metallic foil portion and, by contact with said metallic foil
portion, thereby activating said adhesive plastic coating on the
exterior surface of said liner,
e. and, thereafter, pressing said glue flap and said main panel of
said carton blank most remote therefrom together to complete said
side seam.
6. A method of forming a side seam for a lined carton as defined in
claim 5 including using an extruded coating on said liner material
for said adhesive plastic coating.
7. A method of forming a side seam for a lined carton as defined in
claim 5 including the step of feeding said carton blanks in
substantially a straight line throughout the formation of said side
seam.
8. A method of forming a side seam for a lined carton as defined in
claim 5 including the step of using an R.F. induction coil having a
length more than twice the length of said paperboard blank.
9. A method of forming a side seam for a lined carton as defined in
claim 5 including the step of feeding said blanks continuously at
linear speeds in excess of 400 feet per minute in the course of
forming said side seam.
10. A method of forming a side seam for a lined carton as defined
in claim 5 including the step of water cooling said R.F. induction
coil.
Description
This invention relates to hermetically-sealed, lined carton
constructions and, more particularly, to blank constructions for
use therein and methods of forming same.
The use of paperboard cartons in the packaging industry has been
limited by virtue of the inability to provide a hermetically sealed
paperboard carton. Consequently, the paperboard carton, despite
certain economic advantages, has not been able to compete with the
all metal container. One limiting factor has been the inability to
protect the longitudinal edge of the carton so as to make it
impervious to air and moistire leakage through the pores of the
paperboard stock. Attempts to wrap an impervious barrier around an
edge of the seam area such as by the use of a foil liner has
created sealing problems in that a foil-paperboard or foil-foil
seal does not possess as much strength as a paperboard-paperboard
seal area.
In accordance with the present invention, the foregoing problems
are effectively overcome by providing a carton construction in
which an edge adjacent the longitudinal seam is covered with an
impervious foil-containing material while still providing a
paperboard-paperboard seal area.
Additional factors have limited the use of paperboard cartons as a
substitute for all metal containers. For example, manufacturers are
reluctant to change from one type of container to another unless
the equipment for handling the new container is already in
existence. Accordingly, one feature of the present invention is to
permit the manufacture of a hermetically sealed, lined paperboard
carton on equipment which is already in existence and for which
reliability has already been established.
An additional difficulty which is inherent in many paperboard
cartons is the weakness of the longitudinal seam itself occasioned
by the proximity thereof to the corner of the carton. Therefore, it
is a further feature of the present invention to improve the
strength of the side seam by devising a seam which may be spaced a
substantial distance from the corner of the carton, if desired.
The inherent advantages and improvements of the present invention
will becom more readily apparent upon considering the following
detailed description of the invention and by reference to the
drawings in which:
FIG. 1 is a plan view of one carton blank construction made in
accordance with the present invention;
FIG. 2 is an end view of the carton blank construction of FIG.
1;
FIG. 3 is a fragmentary elevational view taken in horizontal cross
section along line 3--3 of FIG. 1;
FIG. 4 is a plan view of a modified carton blank construction made
in accordance with the present invention;
FIG. 5 is a fragmentary elevational view taken in horizontal cross
section along line 5--5 of FIG. 4;
FIG. 6 is a fragmentary elevational view taken in horizontal cross
section along line 6--6 of FIG. 4;
FIG. 7 is a plan view of another modified carton construction made
in accordance with the present invention;
FIG. 8 is an end of a carton blank construction of FIG. 7;
FIG. 9 is a fragmentary elevational view taken in horizontal cross
section along line 9--9 of FIG. 7;
FIG. 10 is a fragmentary elevational view taken in horizontal cross
section along line 9--9 of FIG. 7;
FIG. 11 is a fragmentary perspective view, drawn to a reduced
scale, showing a liner within a partially erected carton blank of
the type illustrated in FIG. 1;
FIG. 12 is a fragmentary perspective view, drawn to the scale of
FIG. 11, showing a liner within a partially erected carton blank of
the type illustrated in FIGS. 4 and 7;
FIG. 13 is a fragmentary perspective view showing a step subsequent
to FIg. 12 in the formation of a completed carton;
FIG. 14 is a top plan view of the paperboard strip material;
FIG. 15 is a bottom plan view of the paperboard strip material of
FIG. 14;
FIgs. 16-19 are cross sectional views of cartons illustrating
variuus side seam constructions;
FIG. 20 is a fragmentary cross sectional view, drawn to an enlarged
scale, of a modified side seam construction;
FIGS. 21-26 are schematic side elevational views illustrating the
steps of several methods of making cartons in accordance with the
present invention;
FIG. 27 is a schematic fragmentary perspective view illustrating
the application of an aqueous adhesive to a blank such as is used
to form the carton of FIG. 18;
FIG. 28 is a schematic fragmentary perspective view illustrating a
spiral folding operation subsequent to the application of adhesive
in FIG. 27;
FIGS. 29-31 are fragmentary elevational views taken in horizontal
cross section taken along lines 29--29, 30--30 and 31--31,
respectively, of FIG. 28;
FIG. 32 is a plan view of the spiral fold element of FIG. 28;
FIG. 33 is a right side elevational view of the spiral fold element
of FIG. 28;
FIG. 34 is a fragmentary perspective view illustrating a carton of
the type shown in FIG. 27 after a hot melt adhesive has been
applied;
FIG. 35 is a simplified and fragmentary schematic perspective view
illustrating R.F. induction heating of the side seam of a carton
such as is shown in FIG. 34;
FIG. 36 is a top plan view of an R.F coil heating element;
FIG. 37 is an elevational view taken in horizontal cross section
along line 37--37 of FIG. 36;
FIG. 38 is a perspective view, schematic in nature, illustrating
pressure roller means for sealing the side seam of the carton;
FIG. 39 is a perspective view of a partially folded blank
illustrating the overhang of the liner with respect to the body of
the carton blank;
FIGS. 40-42 are elevational views taken in horizontal cross section
illustrating the relative position of the liner with respect to the
glue flap and the application of two kinds of adhesive;
FIG. 40a is an enlarged fragmentary elevational view taken in
vertical cross-section illustrating the laminated composition of
the carton blank of FIG. 40;
FIG. 43 is a fragmentary perspective view illustrating another
embodiment of the present invention;
FIG. 44 is a fragmentary end elevational view taken in vertical
cross-section of the blank and adhesive applicator of FIG. 43;
FIG. 45 is a fragmentary end elevational view taken in vertical
cross-section illustrating the blank and one of the radiant heaters
of FIG. 44;
FIG. 46 is a fragmentary end elevational view taken in vertical
cross section illustrating the blank and another of the radiant
heaters of FIG. 44;
FIG. 47 is a fragmenary end elevational view taken in vertical
cross-section illustrating the side seaming of the blank of FIG.
44; and,
FIG. 48 is a side elevational view taken in vertical cross-section
of one of the radiant heaters of FIG. 44.
Referring now to FIGS. 1-3 of the drawings, there is illustrated a
paperboard carton indicated generally at 10. The carton is shown to
comprise a paperboard base member 12 to which a lining material
indicated generally at 14 is secured by suitable means such as an
adhesive or plastic film 16 which is shaded in FIG. 1 for purposes
of illustration. The liner material 14 comprises metal foil 18,
such as aluminum foil, which may be laminated to a plastic film 20.
Alternatively, the liner material 14 may be composed entirely of
foil or the foil may be laminated as a pre-prepared stock to a
paper material such as tissue paper or the like.
Referring to FIG. 1, the main panels of the paperboard carton 10
are shown to comprise a side panel 22, top panel 24, side panel 26,
bottom panel 28, and a glue flap panel 30. If desired, the glue
flap panel may be attached to one of the side panels, such as side
panel 22, in palce of either the top or bottom panel. Each of the
main panels 22 through 30 are hingedly connected in conventional
manner by score lines 31 and their lateral extent is defined by a
pair of paralled score lines 33. Attached to the main panels at the
score lines 33 are pairs of dust flap panels 32, end flap panels
34, dust flap panels 36, end flap panels 38, each of which are
separated by slits or cuts 40 which are substantially colinear with
score lines 31, all conventional in construction.
As best seen in FIGS. 1 and 3, the liner material 14 is provided
with an overhang area 42 at one end of the paperboard carton 10, in
this instance, overhanging the glue flap panel 30. The opposite end
of the liner material 14 is substantially coterminous with the free
edge of side panel 22. It will also be observed, as seen best in
FIG. 2 and as indicated by the shading in FIG. 1, that the lining
material 14 is not secured to any of the dust flap panels 32, and
end flap panels 34, dust flap panels 36, or end flap panels 38,
whereby the liner material may be fin sealed in these areas in a
manner disclosed hereinafter so as to provide a hermetically sealed
carton.
Reference is now made to FIGS. 4-6 wherein a modified form of
carton blank construction is illustrated. Specifically, the shaded
area indicates an adhesive securement by adhesive 16 of the liner
material 14 to the paperboard base 12. In this embodiment the area
of adhesive securement also includes pairs of triangular areas on
the pairs of dust flaps 32 and 36. These triangular areas are
indicated by numerals 52 and 54 and are beneficial in forming the
fin sealed areas in a manner to be described hereinafter. The base
of each triangular adhesive area 52 and 54 is substantially equal
to its adjacent and associated side panel. In all other respects,
the carton 50 is identical to the carton 10 illustrated in FIGS.
1-3.
Reference is now made to FIGS. 7-9 wherein a still further
embodiment of a carton blank construction is illustrated. In these
figures, and as best seen in FIG. 7, the adhesive securement by
adhesive 16 of the liner material 14 to the paperboard base 12 is
such that the entire blank is coated with adhesive. Thereafter, a
release coating 66 indicated in FIG. 7 by the additional shading
lines applied to each of the opposed pairs of dust flap panels 32
and 36 and pairs of end flap panels 34 and 38, whereby the liner
material 14 is free from the paperboard base 12 in all areas
corresponding to the free areas in the FIG. 4 embodiment. That is
to say, the liner material 14 is adhesively secured to the
paperboard base 12 in the triangular areas 62, 64 of the opposed
pairs of dust flap panels 32 and 34 but in all other areas of dust
flap panels 32 and 36 as well as from all areas of the end flap
panels 34 and 38 the liner material is free from the paperboard
base 12. Accordingly, the liner material may be fin sealed to
itself in these areas of the carton in order to provide a
hermetically sealed carton.
Referring to FIGS. 11 to 13, there is illustrated the manner of
assembly of the liner material 14 with respect to the erected
carton blank and of fin sealing the liner material 14 to itself.
Thus in FIG. 11, it will be observed that the liner material 14 is
completely free from the dust flap panels 32 and 36 as well as from
the end flap panels 34, 38. The liner material, therefore, may be
fine sealed to itself, with the plastic film 20 facilitating a heat
seal therebetween. FIGS. 12 and 13, further illustrate the
advantages which accrue to the use of triangularly-shaped adhesive
portions such as at 52, 54 in FIG. 4 and at 62, 64 in FIG. 7 in
effecting a fin seal. As the dust flap panels 32 and 36 are bent
progressively backward from an in-line position with side panels
22, 26 to the position of being at right angles thereto as shwon in
FIG. 15, the gap between opposed faces of the liner material
associated with end flap panels 34, 38 becomes less and less
whereby it becomes relatively easy to fin seal the opposed faces
together with the aid of plastic film 20 on each face. Since the
end seal is identical at each end of the carton, only one end is
shown.
One method of forming carton blanks is illustrated in FIGS. 14 and
15. FIG. 14 is a view of a web of blank forming material as seen
from the outside of the carton, and FIG. 15 is a view of the same
web as seen from the inside of the carton. As will become apparent
from the discussion, five successive forming stations are shown in
each figure proceeding from the top of the drawing to the bottom
thereof. FIGS. 14 and 15 are related on a linear basis in
indicating corresponding conditions for the outside and inside of
the web at these stations. A paperboard strip 70 is advanced
continuously and progressively (by conventional means, not shown)
from the top of the drawing toward the bottom. Numeral 72 indicates
a printed area on the outside of the paperboard strip 70 in the
first station. Since nothing occurs to the inside of the blank at
this station it remains unaltered. The area 72 generally conforms
to the outline of the blank to be cut. At the second station a
release coating 66 is printed on the underside or inside of the
paperboard strip 70 which is in registry with the printing 72 on
the outside of the strip.
At the third station, slits 40 are cut through the paperboard strip
72 as well as a cut pattern which defines the general contour of
the adhesive flap 30. This cut pattern comprises a pair of opposed
angled cuts 74, symmetrical about a central longitudinal axis, and
a cut 76 which joins or interconnects the outermost ends of the
opposed angle cuts 74.
At the fourth station, a strip of liner material 80 is laminated,
by any suitable means, such as by an adhesive to the underside of
the paperboard strip 70.
At the fifth station, die cuts 82, 84, 86 and 88 are made and four
crease lines 31 and a pair of parallel crease lines 33 at right
angles thereto are impressed into the blank construction whereby
the entire blank is formed. As can be observed in FIG. 14, by
virtue of the lowermost slits or cuts 40 along with angle cuts 74
and cut 76, a peice of paperboard 90 remains which is then stripped
out from the paperboard strip 70. This paperboard piece 90 is
identical to the amount of overhang 42 by which the strip of liner
material 80 overhangs the edge of the finished blank.
Referring now to FIGS. 16-19, a number of typical longitudinal side
seam constructions are shown. In FIG. 16, the paperboard body is
indicated by numeral 100 and the liner material by numeral 102. The
glue flap is shown at 30 and the overhang material 42 of the liner
102 is shown to be secured to the underside of the liner on the top
flap.
A modification is shown in FIG. 17 wherein the overhang 42 is
removed and a separate strip 104 is heat sealed to the liner
material 102 and the underside of the liner attached to the glue
flap 30.
In FIG. 18, the overhang 42 is brought upwardly and rearwardly over
the glue flap panel 30 and then heat sealed to the underside of the
liner 102 on the top flap of the paperboard body 100.
In FIG. 19, the overhang 42 is secured to a main panel of the
carton when the blank is erected. As in FIG. 18, overhang 42 is
folded upwardly over the edge of an underlying flap 112 of the
paperboard body 110 which underlies an overlying panel 114. The
amount of overhang 42 is heat sealed to the adjacent liner material
102. The side seam as shown in FIG. 19 which is removed from the
corner area for a more positive side seam is frequently employed in
very small cartons.
Referring now to FIG. 20, a modification of the longitudinal seam
shown in FIG. 19 is illustrated. In this embodiment, the underlying
panel is shown at 112 and the overlying panel at 114 as in FIG. 19.
The liner material, however, preferably has at least an outer layer
of foil 120, such as aluminum foil, and may have as shown in FIG.
20 an inner layer of tissue paper 122. Alternatively, the entire
liner may be of foil, such as aluminum foil. The liner is
illustrated to be folded upwardly over the edge 126 of the
paperboard underlying panel 112 and then rearwardly over the upper
surface 128 of the underlying panel 112. An adhesive 130 secures
this rearwardly bent portion of the liner material to the upper
surface 128 of the underlying panel 112. The adhesive 130 may be a
heat sealed adhesive or may be an aaqueous adhesive, as desired.
The edge 132 of the upper liner which is adherred to the overlying
panel 114 is shown to be spaced inwardly from the edge 134 of the
overlying panel 114. An adhesive 136, which may be of a hot melt
adhesive or a heat seal adhesive or the like is therefore
positioned directly between the underlying panel 112 and the
overlying panel 114 and extends between the liner material attached
to upper panel 114 and the liner material which is bent rearwardly
and attached to the upper surface 128 of the underlying panel 112.
The edge 138 of the lower liner is preferably substantially
coterminous with the edge 132 of the upper liner. Also, it is
preferable that the inward spacing of the edges 132 and 138 of the
upper and lower lining materials, respectively, are at least less
than half of the amount of overlap of panel 114 over panel 112.
Referring now to FIG. 21, there will be described one of a number
of methods by which the blanks of the present invention may be
formed. Illustrated in FIG. 21, is a roll 140 of paperboard stock
which is withdrawn by rolls 142 and reversely printed by the
lowermost roll 142 which communicates with a supply of release
coating in receptacle 144. The web 70 of paperboard material is
thereafter passed through an oven 146 wherein the release coating
is dried and the webs then fed through a first set of printing
rollers 148 one of which communicates with ink in receptacle 350
and then through a second set of printing rolls 352, one of which
communicates with ink in a similar receptacle 350. The web is
reintroduced into the oven 146 where the ink is dried and the web
70 then passes out of the oven and is subjected to the action of
cutters on a rotary die 354 and a back-up roll 356 therefor. This
operation corresponds to station 3 in FIGS. 14 and 15 wherein the
slits 40 and the pair of cuts 74 and 76 defining the contour of the
glue flap panel 30 are placed on the strip 70. Web 70 is then
preferably wound up on a take-up roll 360.
Referring now to FIGS. 22, 23 and 25, it will be observed that in
each of these figures the starting position is the paying off of
web material from the take-up roll 360. In FIG. 22, for example,
the strip 70 is payed off from take-up roll 360 and simultaneously
a pre-prepared liner stock is payed off from roll 370 and the two
webs laminated with the aid of laminating rolls indicated
schematically at 372 and the resulting web being under the
influence of feed rolls 374. This corresponds to the fourth station
in FIGS. 14 and 15. The laminated stock is then fed between a die
cutter 376 and an anvil 378 with relative motion between the die
cutter 376 and anvil 378 being indicated by the reciprocating arrow
thereby producing a finished blank 10.
In the alternate method shown in FIGS. 23 and 24, the stock
material is fed from take-up roll 360 and a roll of metal foil such
as aluminum foil is payed off from roll 380. Feed rolls are shown
at 328 and laminating rolls at 384 effect an initial lamination
between the web of material from take-up roll 360 and roll 380 of
metal foil. The composite is then fed to a plastic extrusion means
indicated generally at 390 which extrudes a plastic material 16
onto the upper surface of the metal foil. The web is then rewound
on take-up roll 400 and this roll is then used as the starting
material in FIG. 24 in which the material is fed from take-up roll
400 under the influence of feed rolls 402 to a die cutter means 376
and anvil 378 therefor comparable to those shown in FIG. 22 which
again produce a finished blank 10. The die 376 reciprocates
vertically as indicated by the arrow. As a modification, it is
possible to go directly from the laminating step from the plastic
extrusion means 392 to the die cutting step by passing the web
directly between die cutter 376 and anvil means 378.
In FIG. 25, the take-up roll 360 again is the starting material and
the web is fed by means of rollers 402 directly to a die cutter 376
and anvil means 378 where individual paperboard blanks are
formed.
These paperboard blanks 410 are then stacked as shown in FIG. 26,
and become the input material to a feed roll means indicated
schematically at 412 which feeds individual blanks sequentially to
an adhesive applying means 414 which applies adhesive to pattern
applicators 416 which in turn engage individual blanks in
synchronism so as to apply a register adhesive pattern thereon. The
adhesively coated blanks are fed forwardly between a vacuum drum
418 and a back-up roll 426. Meanwhile, a pre-prepared liner stock
is fed from roll 420 toward the vacuum drum 418. The liner stock is
cut to individual blank size by means of rotation of knives 422 on
the vacuum drum 418. Knives 422 mate with a slot in roller 424 so
as to sever an individual blank of liner stock from the web of the
material and the vacuum roll applies the precut liner material in
registry with the adhesively coated blank whereby a completed
container blank 10 is formed therefrom with the aid of back-up roll
426. The method shown in FIGS. 25 and 26 may be practiced in
conjunction with so-called "window" applying machines which are
standard in the packaging industry for applying a heat sealable
plastic material to a paperboard carton so as to make the contents
thereof visible. Thus no new equipment need be designed.
As will be apparent, the contemplated blanks may be formed such as
are shown in FIGS. 1, 4 and 7 with the liner material overhanging
one end of the blank at 42 to facilitate formation of the side
seams such as are shown in FIGS. 15-19. The liner material is free
in the areas of dust flap panels 32, 36 and end flap panels 34, 38
whereby the freely extending liner material as shown in FIGS. 11-13
may be fin sealed together with or without the aid of the
triangular attachment of the liner to the dust flaps 32, 36 in the
embodiments of FIGS. 4 and 7.
Referring now to FIGS. 27, 28 and 35, a disclosure is made
depicting the method steps employed in an R.F. induction heating
process for making side seams on lined cartons. Carton blanks,
indicated generally at 150 in FIG. 27 and similar to the blank
shown in FIG. 18, are fed in the direction of arrows 152 from a
suitable hopper supply of carton blanks. Propulsion is provided for
the carton blanks 150 by means of one of a number of conveyor belts
154 which are provided as standard equipment on a straight line
gluer such as is manufactured by the Post Machinery Company of
Beverly, Mass.
Roller followers 156 cooperate with conveyor belt 154 to convey
carton blanks 150 toward an adhesive roller applicator 158. The
carton blank 150 is fed in the longitudinal direction of the blank
itself with its liner side up. The adhesive roller applicator 158
is suitably mounted for rotation on a shaft in glue pot 160 so as
to place a stripe of adhesive on the glue flap of the carton blank
150 as it is fed in the direction of the arrows 152. A roller
follower 162 provides a suitable back-up for the application of the
adhesive. For the attachment of the overlap of the liner to the
glue flap, it is preferred to use an aqueous adhesive rather than a
hot melt adhesive since the aqueous adhesive is less expensive and
will suffice for this particular adhesive application.
In FIG. 28, the blank 150 is fed toward a spiral indicated
generally at 164 having substantially flat opposed surfaces 166 and
168. In a preferred embodiment, the spiral 164 is made from
aluminum.
Reference to FIGS. 39 through 42 will illustrate in greater detail
the features of carton blanks 150. Thus each carton is illustrated
to have main panels comprising a top panel 170, a bottom panel 172,
a front wall panel 174 and a rear wall panel 176. The carton blank
150 is also provided with suitable end panels and dust flap panels
but these are immaterial insofar as the present invention is
concerned. The main panels 170 through 176 are separated from
though hingedly secured to adjacent panels by score lines 178, 180,
182 and 184 in conventional manner.
The locus of deposition of an aqueous adhesive, identified at 186
in FIGS. 29-31, is shown schematically by the legend and arrow in
FIG. 40. The blank 150 is further provided with a glue flap 188 and
a liner indicated generally at 190 with the latter being provided
with an overhang portion 192 illustrated best in FIGS. 39 and 40.
The liner 190 has at least a portion thereof indicated at 191 made
from metallic foil, such as aluminum foil, and an external plastic
coating thereon at 193. Plastic coating 193 is preferably an
extrusion coating.
Referring again to FIG. 28, as the carton 150 approaches spiral 164
an entrance guide means is provided at 198 which, coupled with an
upturned end 200 of spiral 164, ensures that the blank 150 is fed
properly into engagement with spiral 164. Wire-like guiding members
194 and 196 suitably mounted to the frame of the in-line gluer
entrain the glue flap 188 and overhang 192 of liner 190 against the
flat opposed surfaces 166 and 168 of spiral 164.
As is illustrated sequentially in FIGS. 29-31, the net effect of
the spiral 164 with its cooperating guiding wires 194 and 196 is to
achieve a 180.degree. turning of the overhang portion 192 of liner
190. In this manner, the overhang portion 192 is brought into
engagement with the stripe of aqueous adhesive 186 previously
applied to glue flap 188 by the adhesive roller applicator 158 of
FIG. 27.
The details of the aluminum spiral 164 are further illustrated in
FIGS. 32 and 33 together with its associated mounting blocks or
brackets 202 and 204 which facilitate the attachment of the spiral
164 to the frame of the in-line gluer. After the overhang 192 of
liner 190 has been folded against the glue flap 188, the plastic
extrusion coating 193 on the aluminum foil 191 of liner 190 is in
position to be activated by an R.F. induction coil in a manner to
be described.
The carton 150 is then progressively folded in conventional manner
by folding plows which are standard equipment for the in-line gluer
so as to fold the carton into substantially tubular shape so as to
bring the top panel 170 into a position closely adjacent the glue
flap 188. An R.F. induction coil, indicated generally at 210 in
FIGS. 35-37, is mounted on the in-line gluer so that when a
continuously advancing blank 150 reaches its folded condition where
the top panel 170 is closely adjacent glue panel 188, the R.F.
induction coil 210 becomes interposed therebetween.
R.F. induction coil 210 is shown to be of the folded butterfly type
with the coils 212 thereof being hollow and being encased within an
epoxy plastic 214. The coils 212 are thereby adapted to receive
water therethrough in order to cool the R.F. induction coil 210. An
inlet tube 216 and an outlet tube 218 cooperate with a water
coolant source indicated schematically in FIG. 35. The R.F.
induction coil 210 is positioned downstream from a suitable forming
mandrel 220 about which the final folding of the carton 150 may
occur as it is being fed continuously in the direction of arrows
152. In order to ensure that the natural resiliency of the carton
does not remove the main top panel 170 from its folded position
closely adjacent the glue flap 188, a stationary guide means 222 in
FIG. 35 may be positioned so as to contact and hold top panel 170
in its desired position.
As is illustrated in FIGS. 35-37 of the drawings, the R.F.
induction coil 210 is essentially in the form of a blade and is
relatively long with respect to the length of a carton 150. Thus it
is preferred that the length of the R.F. induction blade coil 210
be at least twice as long as the length of the carton blank 150 and
may approach three or more times the length. The blanks 150 are fed
over the blade R.F. induction coil 210 at linear speeds in excess
of 400 feet per minute so as to process from 500 to 600 per minute.
The energy applied to the R.F. induction coil from a suitable
source, not shown, in one illustrative example is in the order of
3,500 watts of R.F. energy at a frequency of 450 kHz. As the
frequency increases there is a tendency to heat only the surface of
the blank in what amounts to a skin effect. It is preferred to have
the closely positioned panels, namely, panel 170 and glue flap 188,
as close as possible since the energy received varies inversely as
the square of the distance that the panels are from the induction
coil.
After being subjected to the inductive heating action of R.F. coil
210, the blank is fed into the compression section of the gluer
where the final side seam is made. This is illustrated
schematically in FIG. 38 wherein a pressure roller 224 having a
suitable anvil or back-up means completes the side seam. Finally,
in this section of the in-line gluer, the tubular blanks are
overlapped in a shingled arrangement.
While the operation of the in-line gluer on the blank 150 will
apparent from the previous discussion, a brief summary thereof is
believed to be in order. The blanks 150 are fed from a suitable
source such as a hopper in the direction of arrows 152 with the
liner side up and fed in the longitudinal direction of the blank.
Thus there is no registration problem with respect to the
application of an aqueous adhesive by adhesive roller applicator
158 to the glue flap 188 and marginal portions of the overhang
portion 192 whicis in line therewith.
The blank 150 is then continued on its continuous feed to a spiral
164 which facilitates the folding of the overhang portion 192 of
liner 190 through substantially 180.degree. as is depicted
sequentially in FIGS. 29--31. In this position, the plastic
extursion coating 193 on the aluminum foil 191 of liner 190 is in
position to be activated by the R.F. induction coil 210.
In order to effect this, the carton blank is folded into
substantially tubular shape to bring the top panel 170 closely
adjacent and preferably substantially parallel to the glue flap 188
having the plastic extrusion coating 193 uppermost. At this point
of travel of the carton blank, the R.F. induction coil 210 is
interposed therebetween and the plastic extrusion coating 193 is
heated and activated thereby. Thereafter, pressure roller 224
compresses the top panel 170 and glue flap 188 against a suitable
anvil or back-up means 226 to complete the side seam.
While the present embodiment has been illustrated and described
specifically with respect to the blank of FIG. 18, the method of
forming side seams for lined cartons may be practiced on other
blank constructions including those shown in FIGS. 17 and 19.
An alternative embodiment is illustrated in FIGS. 43-47 wherein a
hot melt adhesive 208 is applied to blank 150 by means of a roller
applicator 228. As in the embodiment of FIGS. 27, 28 and 35, the
blank 150 is fed continuously forward in a straight line path by
means of conveyor belt 154. Prior to the arrival of a particular
blank 150 at the station illustrated in FIG. 43, the overhang 192
has been folded by spiral 164 and adhesively secured to glue flap
188 in the manner previously described.
In this embodiment, it is essential to maintain the hot melt
adhesive 208 hot during the folding operations of the blank. This
is preferably accomplished by directing heat toward the hot melt
adhesive while simultaneously folding the blank into tubular
shape.
Accordingly, FIG. 43 illustrates a bank of radiant heaters 232,
234, 236, 238, 240, 242 and 244. The ends of each of the radiant
heaters 232 through 244 are so arranged so as to be directed at the
hot melt adhesive 208 while the blank 150 is being folded by a
suitable folding mechanism, indicated generally at 230 in FIG. 43.
FIGS. 44 and 45 disclose two illustrative examples of how two
different radiant heaters, namely 234 and 236 are positioned to be
pointed substantially at the hot melt adhesive 208 in different
folded positions and thereby maintain the adhesive hot until the
blank is folded into the position of FIG. 47 where a suitable
roller 224a presses the main top panel 170 against the glue flap
188 to effect a side seam with the aid of hot melt adhesive
208.
The radiant heaters 232 through 244 are held by support mechanism
246 so as to effect the desired positional relationship with
respect to the hot melt adhesive. An input pipe 248 delivers
compressed air into a manifold 250.
Reference to FIG. 48 shows the details of an individual radiant
heater, such as radiant heater 232. A heating element 252 is shown
encased within an open ended glass tube 254 each of which is held
by holder 256. Electrical connecting leads 258 and 260 are shown
for the heating element 252 and connected to a suitable source of
electrical power, not shown. Chamber 262 is provided for admittance
of the compressed air which then enters tube 254 and is heated as
it passes over the heating element 252 and directed toward the hot
melt adhesive through the open end of tube 254. Thermostat control
means may be used for each of the radiant heaters 232-244.
In the embodiments of FIGS. 43-47, it is possible to apply the hot
melt adhesive atop the glue flap 188, as indicated schematically in
FIG. 41, and to utilize radiant heaters to maintain the hot melt
adhesive sufficiently hot while the carton blank is being folded
into tubular shape. As in the previous embodiment, the blanks may
be fed continuously forward at linear speeds in excess of 400 feet
per minute.
While presently preferred embodiments of the invention have been
illustrated and described, it will be recognized that the invention
may be otherwise variously embodied and practiced.
* * * * *