CA1036990A - Shipping case for cartons or containers - Google Patents

Abstract

Abstract of the Disclosure A shipping case of fragile product-filled cartons is made up of a rectangular sleeve of corrugated fiber-board having open ends and having the corrugations thereof running between the open ends. A plurality of cartons are stacked in rectangular configuration in the sleeve and carton occupy the entire volume of the sleeve, with exposed carton faces forming a substantially planar surface at both ends of the sleeve. Heat shrinkable transparent film in the form of band is disposed around the open ends of the fiberboard sleeve and around at least two opposite walls of the sleeve, and is shrunk, in order to contain the sleeve and cartons together as an integral unit, thereby providing a shipping case without end flaps.

Description

~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 ~3tj~9~

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 3f~
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 ~3~g~) 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 t,g~O

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 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.

~L~t!3t~
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 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

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 : _ 9-1~3~
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~.

Claims (2)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A shipping case adapted to be stacked vertically upon and under other such cases and consisting essentially of a rectangular sleeve of a single or multiple wall corrugated fiberboard with two opposed open ends, a plurality of rectangular cartons packed in said sleeve in engagement with one another and the four walls of said sleeve, said cartons filling said sleeve, and an overwrap applied around said corrugated sleeve, said overwrap including walls tightly overlying and engaging the outwardly facing surfaces of said cartons at the open ends of said corrugated sleeve and a pair of opposed walls and all eight corners of said sleeve, said overwrap walls at least partially overlying the other pair of opposed walls of said corrugated sleeve; character-ized in that said corrugated sleeve is joined together so as to form a continuous corrugated sleeve stackable on its open ends with the corrugations thereof running vertically between the open top and bottom ends and parallel to the four corners of said corrugated sleeve, that said cartons are crushable cartons contained in said corrugated sleeve under pressure so that said cartons exert pressure out-wardly against said corrugated sleeve and said corrugated sleeve exerts pressure inwardly against said cartons, that said cartons fill the entire volume of said corrugated sleeve in firm contiguous engagement with one another and the four walls of said corrugated sleeve and have outwardly facing surfaces at the open top and bottom ends of said corrugated sleeve forming substantially planar surfaces flush with the top and bottom edges of said corrugated sleeve and retained therein by said overwrap, and that corresponding vertical walls of said cartons are aligned with one another and are parallel with the other vertical walls of the cartons and the walls of said corrugated sleeve so that the strengths of said cartons and said corrugated sleeve are combined to impart increased vertical stacking strength to the shipping case.

2. A shipping case as defined in claim 1 wherein said overwrap is made from a heat shrinkable polymeric material and is shrink fitted around said corrugated sleeve.