Note: Descriptions are shown in the official language in which they were submitted.
~1~3~ 30
Rectangular filled cartons are normally shipped in
conventional closed flberboard cases made up of corrugated
material and having overlapping flaps at both end~. In the
case of food and other products, the cases must be strong
enough to withstand usual handling and stacking ~orces and
must be sealed to protect the contents from contamination,
injury, and tampering. Upon arrival at the retail outlet,
the cases are cut open and discarded, and the indlvidual
cartons are price tagged and displayed on shelv~s. The cost
of the case and the expense of its disposal add to the coAt
of the product in the carton. As the cases are cut open,
several of the inner containers are sometimes cut and must
be discardedO
me u~e of polymeric heat shrinkable films for the
packagine of materials i9 well known and is deæcribed in the
following ~nited States patents: 3,219,183; 3,058,273;
2,711,346; 3,416,288; 3,338,406; 3,050,4023 3,198,327;
3,447,675, and 3,694,995. The prior art generally deals
with heat shrinkable materials disposed around a plurality
of rigid or hard objects, such as steel cans, in order to
hold the ob~ects together as a unit package, either in a
spaced or contiguous relationship. One problem with such
packages resides in the difficulty of applying printed
information to the exterior polymeric surface. Also well
known are corrugated trays in combination with a shrinka~le
film to hold ob~ects thereon in a stacked relationship. A
problem with such arrangement is that the vertical strength
of the package is limited to the strength of the stacked
ob~ects.
3 In accordance with the present in~ention, I have
discovered an inexpensive method for packaging a plurality
of filled rectangular paperboard cartons, which totally
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eliminates the need for a conventional shipping c~se havlng
overlapping end flaps, thereby ~igni~icantly reducing the
material cost of the case.
The conventional case is replaced with a
rectangular sleeve or tube having open ends and no end
flaps. The sleeve is preferably composed of corrugated
material having the corrugations runnlng from one open end
to the otherc The sleeve is sized such that a plurality of
rectangular cartons, when compression packed in contiguous
fashion in the sleeve, completely ~ i 1 1 the volume of the
~leeve with outwardly faclng walls of the cartons present-
ing a substantially flat surface at the open ends of the
sleeYe. A band of transparent heat shrinkable polymeric
film is then disposed around the open ends o~ the sleeve and
over two opposite walls Or the sleeve and is shrunk by
application of heat to form Q unitary case, the end~ of which
are ~or~ed o~ the carton surfaces and thermoplastic filmo
When the case i8 constructed properly, the
vertical compressive or end strength is unexpectedly superior
to that of conventional filIed cases, thereby enabling, if
desired, the use of lower weight packing materials with
attendant cost savingsO The improved end strength is due to
the combined strength of the cartons and the corrugated
sleeve. Compression packing o~ the cartons in the corrugated
sleeve results in the best possible alignment of all l~ad
bearing members, particularly the individual cartons. The
cartons thus contribute to end strength to a greater degree
than do the c~rtons in a conventional case having flapsO
There is another reason for strength improvement
in the case of the present inventionO In the assembly of a
conventional corrugated case having end ~laps~ it is
virtually impossible to maintain the case in a square
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configuration as the flaps are being glued closedO Any
skewing of the rectangular base will also result in a con-
cave configuration in the planes of the flaps. The result
is that the highest portion of the concave conriguration
will pick up the stresses from an external load prematurely,
and cause premature ~atigue and failure, thereby detracting
from the optimum theoretical strength levels. The
improved case construction o~ the present invention does not
employ flaps and is more flexlble, thereby affording the
unique ability to simultaneously plck up an external force
across the maximum bearing ar~a and minimizlng fati~ue or
damage to isolated force level~O
Since the cartons are visible through the trans-
parent overwrap, there is less likelihood that the cartons
will be da~aged or cut when the case is opened, as compared
with conventional cases having overlapping flaps at the ends.
The fiberboard sleeve presents an excellent printing surface
and for this reason is s~perior to the packing of a plurality
of containers solely by means of a shrink or other flexible
or transparent wrapperO
: Other conveniences and advantages of the present
inventi~n will become apparent from the following detailed
description.
In the drawings:
Figure 1 is a perspective view of the composite
parts of the shipping case of the present i~vention; and
Figures 2, 3 and 4 are perspective views of the
completed shipping case of the present invention, illustrat-
ing the various possible arrangement of cartons in the
corrugated sleeve~
Figure 1 illustrates the three components which
; comprise the shipping caæe of the present invention, namely,
~6~3f~9~)
a rectangular corrugated sleeve 10 having opposite open ends
12, a plurality of rectangular fiberboard cartons 14 adapted
to be packed snugly in the sleev~, and a heat shrinkable
band or tube 16 of sufficient size to slip over and cover
the open ends and a pair of opposite sides of the sleeve.
The band or tube normally will be comprised of integrally
extruded tube stock or flat sheet stock formed into a tube,
or a flat sheet may ~imply be wrapped aroun~ the ends o~
the fiberboard sleeve.
The sleeve 10 may be constructed of suitable sheet
stock ha~ing compressive strength in the direction from open
end to open end thereof, such as vertically oriented conven-
tional corrugated fiberboard wherein a corrugated or fluted
sheet is bonded between a pair of spaced walls. Opposite
ends of the riberboard sheet are connected to form a tube,
and the tube is shaped with four corners running parallel to
the ~lutes. The æleeve 10 thus has four walls connected in
rectangular fashion, and one or more ~alls may carry
desired printed information, such as product identi~ication
or codingO Although singlewall corrugated will normally
provide sufficient strength, double and triplewall corrugated
boards may also be employedO
The sleeve 10 is of a size which is adapted to re-
ceive a plurality of filled rectangular cartons 14 in a
stacked or nested relationship within the sleeve. The
cartons, which would normally be made up from a flexible
fiberboard material, are preferably equi-sized and have sub-
stantially ~lat side and conventional flapped end surfa~es.
The cartons are arranged in a contiguous array and when
properly assembled, as shown in Figure 1, together define a
rectangular solid having a volume which is substantially
equal to the volume between the open ends of the slee7eO The
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solid thus defined by the carton arrangement has six outward-
ly fac~ng and substantially flat ~nd planar surfaces, which
are discontinuous only at the juncture between adJacent
cartons. Four of the exposed surfaces of the arrayed car-
tons are placed in full contact with the respective interior
walls of the sleeve; the other two exposed surfaces of the
array occupy the open ends of the sleeve and are substantial-
ly level with the edges at the open ends. The other
unexposed sur~aces of each carton are in full contact with a
corresponding suxface of an ad~acent carton.
As shown in the figures, the sleeve and cartons
therein define a structurally solid package, with two
opposed end surfaces being made up of the outwardly facing
carton surfaces. In order to hold the cartons in the sleeve
and to increase the integrity of the assembly, the shrink-
able band is wrapped or otherwise provided around the
sleeve so as to overlie the open ends, and is then shru~k
down onto the sleeve (in the direction of the corrugations)
to retain the cartons in a contiguous relationship. Due to
the compressive strength of the corrugations of the sleeve
10, the shrinking of the film down onto the cartons is con-
trolled to provide a firm but not excessive holding force.
The resultant combination of the corrugated sleeve 10, the
carton~ 14 and the band 16 are thus combined to provide a
uniquely strong case having undistorted walls and a high
degree of flexibility in co~parison with conventional cases.
The band 16 is preferably i~ the form of a tubular
section of transparent, heat shrinkable thermoplastic
material, which tube has a large enough diameter to fit over
the open ends of the sleeve and is sufficiently long to
completely cover the open ends with extra material at both
sides. As shown in Figures 2, 3 and 4, the material is heat
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shrunk over the four corners and end edges of the sleeve,
such that the material completely overlies the open ends
and a pair of opposed walls of the sleeve. The edges of
the material lap over onto the other opposed pair Or sur-
~aces of the sleeve and terminate in the form of an oval
window at 18. The band 16 may be conveniently made up from
flat sheet material by joining and heat sealing opposite
edges of an appropriate size flat sheet.
The heat shrinkable material described herei~ may
comprise any of the uniaxially or biaxially oriented
polymeric films which upon application of heat are shrunk to
a decreased surface areaO Suitable films include oriented
polyolefinic films such as polyethylene, polypropylene,
polyisopropylethylene and polyisobutylethylene. Other
exemplary films are polyvinyl chloride polyethylene
terephthalate, polyethylene-2,6-naphthalate, polyhexamethyl-
ene adipamide, and the like, as well as polymers of alpha
mono-olefinically unsaturated hydrocarbons having polymer
producing unsaturation such as is present in butene, vinyl
acetate, methyl acrylate, 2-ethyl hexyl acrylate, i~oprene,
butadiene acrylamide, ethyl acrylate N-methyl-n-vinyl
acetamide and the like. This list is illustrative of the
types of polymeric films known in the art and is not
intended to be exhaustive of all heat shrinkable films,
since many others are known which may be successfully
employed.
The film of the preferred embodiment is a poly-
olefin and preferably biaxially oriented polyethylene. The
thickness is not critical and may vary between at least 1.0
3 to 20 mils. The material is preferably transparent to
reveal the markings on the sleeve and the labels or printing
on the cartons facing the open ends. The film also reduces
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1~)3~
penetration of moisture vapors into the case and allows for
the insertion of information panels under the film.
~ arious possible arrangements of the cartons with-
in the sleeve are shown in Figures 2, 3 and 4. It will be
noted that the completed case is intended to be shipped and
stored with the corrugated flutes disposed vertically, in
order to withstand forces imposed on the case when a
plurality of cases are stacked. It is also important that
the largest and hence weakest panels of the cartons be
arranged or oriented to receive the maximum degree of pro-
tection from the sleeve and film, especiall~ since the case
may be subjected to lateral gripping forces as well as
compressive stacking ~orces during loading and storage. The
arrangements shown in Figures 2, 3 and 4 are designed to
provide such protection, as will now be described.
As shown in Figures 1 and 2, the cartons may be
arranged in the sleeve with their largest panels facing the
open ends of the sleeve or perpendicular to the sleeve
corners. In this manner, the larger panels are protected ~ -
against deflection by the relatlvely rigid ~lutes of the
corrugated sleeve. This arrangement is particularly
beneficial to allo~ display of the cartons in the retail
outlet after the transparent overwrap has been partially or
entirely removed.
In the arrangement shown in Figure 4, the side
surfaces of the cartons are arranged to face outward from the
open end of the sleeve and the larger carton panels and ends
are oriented parallel to respective pairs of opposed walls of
the sleeve. In order to protect the larger panels, the
3 pslymeric band is applied in such a manner that it completel~
overlies the sleeve walls in contact with the larger panels,
in order to impart additional support and protection thereto.
- 7
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Another suitable arrangement is shown in Figure 3,
in which four rows of cartons are provided wlth the ends
facing outward, and the larger ca~ton panels face and are
protected by the sleeve and film ].aminate, and the smaller
side surfaces face the other opposed walls of the sleeve,
which are not protected entirely by the transparent overwrapO
This arrangement is desirable to facilitate the application
of price markings to the top of the carton after the trans-
parent wrap has been removed from either one or both ends of
the caseO
It has been found that the case of the present
invention, when properly packed and compared with a conven-
tional case of the same size having the conventional flaps,
pro~ide~ a top to bottom compressive strength improvement in
the order of 25~ and the case has excellent handling charac-
teristicsO Moreover, elimination of the flaps and the
folding and pasting operation provides for about a 50% reduc-
tion in cost. Compression packing of a sleeve in accordance
with the present inve~tion improves the strength contribution
of the cartons and provides for better squareness that
improves stability for storage and handlingo
The following example is given in further illustra-
tion of the present inventionO
The strength of the shipping case of the present
invention was compared to the strength of a conventlonal
singlewall corrugated case having flapsO The respective
cases were of the same size3 and equal numbers of identical
cartons containing ready-to-eat cereal were packed in each
case in a~ array similar to that shown in Figure 30 The
case of the present invention was made up from a sleeve of
single ply corrugated board of the same specifications as
the board in the conventional case, and the wrap was made up
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1~3~g~
from a 3 mil. tube of biaxially oriented polyethylene. me
open ends of the cartsn-filled tube were covered with the
wrap as ~hown in Figure 1 and the wrap was shrunk to the
maximum extent poss-lble, within the control provided by the
sleeve, by application of heatO Ten cases of each type were
prepared and sub~ected to compression tests on all three
axes. The following table illustrates the te~t results.
Compression Strength
(lbs.)
TB SS ~E
SLEEVE WITH SHRINK WRAP1492 482 246
STA~DARD CORRUGATED CASE 1166 475 473
The terms TB, SS and EE designate top to bottom,
side to side (i.e., from upper right to lower left in
Fig. 3) and end to end (from upper left to lower right in
Fig~ 3) respectively. The end to end strength measurement
was taken in the direction nor~al to the larger carton
panels, and the side to side ætrength measurements correspond
to compression in the narrow di~ension of the carton, while
TB designates compression parallel to the ~lutes or corruga-
tions of the sleeveO
The top-to-bottom strength is the most critical,
since this value determines the extent of permissible
vertical stacking. It ~ay be seen that the top to bottom
strength of the shipping case of the present invention was
28% greater than that of the standard case. The side to side
strengths were essentially the same. The conventional case
-exhibited superior end to end strength, which was due,
primarily, to the presence of the fl~ps. The loss in end to
3 end compression strength, however is not critical.
In actual field tests, where the cases were sub~ec-
ted to conventional handling, including side clamping, the
case of the present invention was found to have more than
: _ 9-
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ade~uate strength both slde to side and end to endO The
significant increase in top to bottom strength was a sub-
stantial and unexpected plus, permitting a 25% increase in
stacking height without any offsetting disadvantages. And
at the same time, costs of the case were reduced by 505~.
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