Shrink wrapped two component open end package and shipping carton
United States Patent 1 [111 3,878,943  
 Ryan et al. Apr. 22, 1975 1 SHRINK WRAPPED TWO COMPONENT Primary Examiner-William 1. Price OPEN END PACKAGE AND SHIPPING CARTON lnventors: Jack A. Ryan; Ross A. Easter: Jack J. Rejsa, all of Minneapolis. Minn.  
 Assignee: The Pillsbury Company,  
 Minneapolis, Minn.  
 Filed: May 24, 1973 Appl. No.: 363,441  
 U.S. Cl. 206/497; 206/4533; 53/30 Int. Cl. B65d 65/00 Field of Search 206/497, 45.33. 504;  
 References Cited UNITED STATES PATENTS Assistant E.\&#39;aminer-Ro E. Hart Attorney, Agent, or Firm-James V. Harmon; Michael D. Ellwein [57] ABSTRACT A generally rectangular shipping package is described comprising a carton having at least five sides. enclosed within a shrunken packaging lfilm which increases the strength of the package and allows the package to be opened at the top without cutting into the products packaged within the carton. The carton is separable into two parts along a horizontal line extending circumferencially near the bottom of the carton to define a display tray when the top portion of the carton i.e., the side wall is removed. The package can be prepared by placing product in a sleeve which forms the carton sidewall, next placing the bottom of the carton over the &#39;ends of the product projecting from the sleeve and overwrapping the assembled product and carton with heat shrinkable film to form a tube with portions of the film extending beyond the opposed ends of said carton. The package is then passed through a heating tunnel to shrink the film around the package.  
 10 Claims, 5 Drawing Figures SHRINK WRAPPED TWO COMPONENT OPEN END PACKAGE AND SHIPPING CARTON FIELD OF THE INVENTION This invention relates to packages and the method of preparing them. In particular, the invention relates to packages made of a combination of rigid and flexible packaging materials for packing receptacles such as boxes.  
 THE PRIOR ART Food products such as cake mixes and other grocery items are generally shipped in twelve or twenty-four unit cases. The most common case package is the ordinary cardboard box which is constructed of corru gated paperboard. These boxes have the disadvantage that the contents cannot be seen and it is difficult to quickly determine the size. shape and nature of the contents. Labels cannot convey the same accurate knowledge of the contents that visual inspection can. When opened by a grocery clerk, the knife used sometimes cuts into the inner boxes of cake mix or other food rendering them unfit for sale. Damage is caused largely because the clerks cut through the tops of the corrugated boxes using razor knives. Knives are the most effective and common means of opening these boxes. A very high level of skill and care is needed to open the boxes without cutting the inner contents.  
 OBJECTS OF THE PRESENT INVENTION It is an object of the present invention to provide a package for wrapping products in case lots so that the contents of the package can be readily observed and opened without damaging the contents.  
  The height to which packaged goods can be stacked for storage or for display is dependent upon the weight and strength of the package. Therefore, it is a further object of the present invention to produce a lighter and stronger package for case lot goods.  
  Another object is to provide an improved method of forming packages in accordance with the present invention in which no special equipment is necessary to press and hold the box together while the bottom portion of the carton is placed on the boxes within the carton.  
  It is another object to provide a readily opened carton which also provides a complete display tray for supporting and holding boxes within the carton after the package is opened.  
  Another object is to provide sufficient stacking strength to allow four pallets each containing six layers of boxes to be stacked one on top of another.  
 SUMMARY OF THE INVENTION These and other objects are accomplished by the novel package of the present invention. The package comprises a separable two-part carton which forms at least five sides of the package. The carton is separable along a line spaced somewhat above its base thereby defining a top portion comprising a tubular sleeve enclosing four sides and a bottom portion enclosing the bottom of the boxes. The bottom portion includes side walls which extend upward a short distance from the bottom panel and the separation line is defined as the upper edges of these side walls and the lower abutting edge of the sleeve. The product is in this way enclosed on five sides by the carton at the time it is shipped. The  
 product and carton are both in turn enclosed in a shrinkable packaging film. The film is then shrunk tightly about the product and receptacle and an easily opened package having increased strength results. The invention also relates in part to a process for forming and filling such cartons namely by assembling the articles to be packaged, moving the sleeve and articles relative to one another so as to slide the sleeve over the assembled articles. placing the bottom on the articles while being held together by the sleeve and then shrinking the film over the carton to press the sleeve against that carton bottom.  
 THE FIGURES FIG. 1 shows diagrammatically a method of forming containers according to the present invention.  
 FIG. 2 shows one embodiment of the present invention.  
  FIG. 3 shows the blank forming the top portion of the carton.  
 FIG. 4 shows the bottom blank of the carton.  
  FIG. 5 shows the bottom of the carton as it is applied to the partially completed package.  
 DESCRIPTION OF THE PREFERRED EMBODIMENT The geometric shape of the packages shown in the drawings is that of a rectangular parallelpiped. However, the invention includes packages having the geometric shape of a cube or a parallelpiped. When used herein, the term rectangular includes these geometric shapes.  
  The term flexible wrapping material&#34; as used herein generally denotes a shrinkable packaging film. Heat shrinkable films are the most common shrinkable films but the invention includes solvent shrinkable films. The invention is not limited to a particular film or method of shrinking film. Cross-linked and oriented polyethylene and polypropylene are among the better known heat shrinkable films. Also included would be heat shrinkable films of rubber hydrochloride, polyvinyl chloride and polyvinylidene chloride. Thus, as used herein, the term heat shrinkable includes films which will shrink upon the application of heat; and the term oriented&#34; includes both uniaxially and biaxially oriented film.  
  The rigid packaging materials from which the receptacles of the present invention are made include pressed paperboard, corrugated paperboard and generally any board-like material made from paper and its derivatives. Also included are rigid materials made from rubber bases and from organic synthetic plastics.  
  In FIG. 2, an embodiment of the invention is shown in which the package 10 is preferably made from corrugated paperboard. The package 10 is formed from a carton made of corrugated board which has been prescored and folded and includes a base portion 13 and sidewall or sleeve portion 14. The product which in this case comprises twelve boxes 15 is completely enclosed by the package 10 except for the open top. A heat shrinkable, thermoplastic film tubular in shape encloses the boxes 15 and the carton 10 except for the opening 12. At the opposed end of the carton is a similar opening 12 which is not shown.  
  The heat shrinkable film which encloses the product and carton can be a seamless tube into which the carton and product have been inserted so that a portion of the tubular film overhangs each end of the package. The tube can also be formed by wrapping the receptacle and product with a sheet of film and then beat sealing of the film ends together. Once the carton has been filled, the film is ready to be applied and shrinking process to be performed as shown diagramatically at 16 in FIG. 1. The film is heated so that it will shrink tightly against the exterior walls of the receptacle. One method of shrinking tubular film to so enclose a product is taught by R. L. Dreyrus in US. Pat. No. 3,215,266 issued Nov. 2, 1965. lfa film shrinkable by other means is employed, then the necessity of heating is eliminated. A solvent shrinkable film would eliminate the necessity of heating for instance.  
  The packages described above which have been prepared according to the present invention have compression strength equal to ordinary corrugated paperboard boxes having the same wall strength.  
  The carton described above is of two piece construction and this is desirable for forming and opening the package according to the preferred method. However, the package can be formed by other methods and the receptacle can be formed from several pieces.  
  The tubular side wall portion or sleeve 14 of the carton can be best seen by reference to FIG. 3, which illustrates a blank from which the sleeve is formed. As can be seen, the blank consists of four major panels 14a-l4d separated by scores, illustrated by dotted lines where folds are made to define the corners of the package and a seam is formed by a tab 14e which is sealed during fabrication to the free vertical edge of the panel 14a to form the sleeve or tube. The tab l4e can be eliminated if a tape (not shown) is employed to seal the adjacent abutting edges of the tube 14 to itself. In this case, the tab Me is glued to the adjacent underlying edge of the panel 14a.  
  Refer now to FIG. 4 which illustrates the bottom part 13 of the carton. The bottom consists of a central rectangular panel 13a defining the bottom of the finished package and four major peripheral flaps l3b-13e. The flaps 13c-l3e have tabs 13f-l3i, respectively, at their side margins so that when all of the peripheral flaps are turned upwardly, their ends can be sealed together by means of the tabs l3f-l3i. Because of the relatively small amount of overlap, it will be understood that the corrugated carton itself can be made of substantially less material than required in conventional cardboard boxes in which the entire top and bottom of the carton normally consists of two overlapped layers of material where the flaps are folded over one another. The top and bottom of the carton abutt on line B.  
  A preferred method of forming the package is to form the blank 14 into a tube. This is done conventionally. The completed tubes can be stacked in a flat condition. In a similar manner the bottom portion of the carton 13 is formed by folding tabs 13bl3e upwardly and sealing the tabs 13f-13i to the adjacent flaps. The remaining portion of the process can be seen best by reference to FIG. 1. As seen in the Figure, the packaged product for example boxes of cake mix 15, are placed on an endless conveyor 52 and carried from left to right as seen in the figure until they reach an assembly station defined by the fixed stop 54. The boxes are then moved laterally i.e., at right angles to the direction of travel of conveyor 52 by means of a reciprocating pusher 56 of the proper size to move six boxes at a time in the direction shown by arrow 57 onto a slide table 58 where the boxes accumulate in groups of 12 as shown at 60. This is accomplished by providing a bar conveyor including bars 62 which are timed with relationship to the operation of the pusher 56 so as to engage each second group of six boxes transferred onto the table 58 whereby they are transferred, twelve at a time, away from the viewer as seen in the figure.  
  When the group of twelve boxes 15 arrive at the position designated 70, relative motion is then established between the group and the sleeve to slide the group into the sleeve. This can be done by sliding the sleeve by hand downwardly over the group of boxes until it reaches the bottom edge of the group. The tops of the boxes extend above the top edge of the sleeve as seen at 72. When the partially formed package slides off the end of the table 58 it travels around a right angle turn roller assembly 74 until it reaches a second slide table 76. The packages are advanced across the top of the table by a second conveyor of any suitable construction such as a bar conveyor 78.  
  The bottom portion of the carton 13 is applied next as can be best seen in FIG. 5. For this purpose, a slide ramp is provided to carry a series of the preformed bottoms 13 to an applicator station 82. To assist in placing the bottoms on the boxes, a movable stop 84 is provided which illustrates one of the several different possible automatic devices for applying the bottoms of the cartons to the package. The stop is pivotally supported at 86 from any fixed object and includes a vertical arm 84a having a carton engaging wheel 84b positioned to initially limit the downward sliding movement of the carton bottom 13 and thereby hold it in the proper position to engage the exposed ends of the boxes 15 as the carton travels from right to left as seen in FIG. 5. When the boxes strike the inside of the carton bottom 13, the stop 84 will pivot to the dotted line position of FIG. 5. As the stop begins to move, a snubber 88 at the end of a piece of a steel leaf spring 89 secured to the top 84 above the pivot 86 will engage the upper surface of the carton bottom immediately beneath it and will prevent this carton bottom from sliding down the ramp 80 until tahe carton has passed the wheel 84b and the wheel itself is returned to its normal position as shown in solid lines.  
  The carton will at this point be in an inverted position. After it is turned over, it is passed through the shrink wrap machine 16 where the film 11 is applied, sealed and shrunk in place thereby preventing boxes 15 from being withdrawn from the top of the carton. The pressure of the film 11 as it is drawn into place holds the sleeve 14 tightly against the upper free edge of thebottom portion of the carton 13 along the separation line B and it is in large part the pressure of the two portions of the carton against one another which provides the requisite stacking strength.  
  It can thus be seen that the packages in accordance with the present invention can be easily formed by semiautomatic equipment, they allow the tops of the boxes inside to be readily seen but protect them from contamination from the outside. It will also be seen that since the sleeve 14 is applied first, the bottom portion 13 of the carton can be readily applied over the ends of the boxes 15 without a special apparatus required to hold the boxes together. Moreover, the invention allows the grocery store clerk to quickly open the packages by running his knife around the periphery of the package slightly below the top, usually an inch or two below the top of the box. He need not make a deep cut at this point, since merely by cutting the film 11 using a very shallow cut, the film can be readily removed. In an actual test, it was found that the damage done to the boxes by opening knives used by grocery store clerks was almost entirely eliminated. It was found that grocery store clerks cut 7 percent of the inside boxes before the invention was used, and only 1 /2 percent in cartons utilizing the present invention. Once the film is removed the upper portion 14 of the carton can be readily removed by sliding it upwardly. This leaves the boxes in the bottom portion of the carton 13 which functions as a tray for supporting and displaying the products in the store.  
  The invention also provides a package having compressive strength substantially equal to ordinary cardboard boxes. The increased degree of strength is due in large part to the compressive force of the film 11 on the two parts of the separable carton at the separation line 15.  
  The top of an ordinary cardboard box consists in most instances of a double layer of corrugated board formed by overlapped flaps. This is entirely eliminated by the present invention. One layer normally found is also eliminated less the small amount of overlap used in the tabs 13f-13i. Thus, the cost of the present package is no more than an ordinary cardboard box due to the elimination of the large areas of overlapping flap material.  
  In addition, the packages of the present invention are suitable for use with a clamp action pickup device which consists of mechanically actuated arms having pads adapted to engage the sides of the carton. This enables packages embodying the invention to be shipped without pallets.  
  In one specific example of the invention, the inner corrugated carton is corrugated fiberboard. The bottom portion 13 has sidewalls (flaps 13b-13e) two inches high. The sleeve 14 extends the remaining height of the boxes 15. The material used for the tray and sleeve has a Mullin burst strength in excess of 125 lbs. per square inch and complies with sections 2 and 3 of Rule 41 of the Uniform Freight Classification. The inner boxes 15 are held together within the carton by a unilaterally oriented polyethylene film 11 two mils thick tightly shrunk around the carton and boxes. The film completely encircles the package except for the holes 12 provided at the end. The film is shrunk not less than 60 percent in the lateral direction and has a minimum tinsel strength of 2600 p.s.i. or more and minimum elongation before break of not less than 650 per cent before being applied. The Elmandorf tear strength of the film is 350 grams or more per mil and the film is provided with an anti-slip surface of any well-known commercially available kind. The gross weight of the package is 14 pounds or less. The strength of the carton is sufficient to allow about 24 cartons to be stacked one on top of one another i.e., 322 lbs. allowing a safety factor of about 300 percent.  
  It will also be understood by those skilled in the art that since corrugated board is not scored and bent at the top to form top flaps, but is instead cut flush with the top of the boxes 15, the invention at least theoretically provides more stacking strength than ordinary boxes.  
 What is claimed is:  
  1. A package for case lot quantities of goods comprising in combination a plurality of packaged containers, a rectangular carton formed from at least two parts which form at least five sides of the package, said carton including a tubular sleeve portion comprising a sheet of paper based board having spaced parallel fold lines therein to define the edges of the carton walls, said sheet having its ends bonded together to define a tube, said carton also having a bottom portion including a flat, rectangular center section and upwardly extending side walls which are relatively short in height compared with the width and length of the package, the edges of the side walls being bonded to one another at their ends to define corners of the bottom portion of the carton and the lower edge of the tubular sleeve portion of the carton being cut to abutt against the upper edge of the side walls of the bottom to form a separation line extending around the entire circumference of the carton and being defined by the upper edge of the sleeve and a packaging film shrunk tightly about the product and the carton to press the sleeve down against the upper edge of the side walls to thereby hold the sleeve and carton bottom under compression along the separation line.  
  2. Package according to claim 1 wherein the film is a transparent film heat shrunk over the carton and the carton contents.  
  3. The package of claim 1 wherein the sleeve comprises a rectangular sleeve having four panels foldably related and a seam extending from the top to the bottom thereof securing the edges of the sleeve together.  
  4. The package of claim 1 wherein the carton bottom is generally tray-shaped and includes a rectangular bottom panel and four vertically extending side walls having a relatively short height compared with the overall length and width of the package and having a cut upper edge extending parallel to the bottom of the package, the edges of the bottom panel being sealed together along their adjacent vertical edges to form the corners of the carton bottom.  
  5. The package according to claim 4 wherein the side walls are sealed together at the side edges by means of tabs extending horizontally from the side walls and bonded to the adjacent portion of the adjacent side wall.  
  6. A method of forming a shipping carton comprising the steps of providing a tubular sleeve composed of stiff fibrous packaging material and having at least four fold lines running from one edge to the other in parallel relationship, providing a carton bottom having a rectangular bottom panel and four vertically extending side walls bonded together at their adjacent edges, assembling the containers to be placed in the package in a group having a predetermined height, width and length, establishing relative motion between the sleeve and the containers to slide the sleeve onto the group thus assembled until the group of containers is enclosed thereby and is retained in an assembled relationship with the ends of the containers projecting from one end of the sleeve, thereafter placing the carton bottom over the projecting ends of the cartons that project from the sleeve while they are retained in the assembled containers in their assembled condition and press the sleeve against the vertically extending; side walls of the bottom portions of the carton thereby strengthening the walls of the carton formed by the combination sleeve and panels to provide a compressive strength substantially in excess of the same two piece carton without the film shrunk thereover.  
  7. The method of claim 6 wherein the film is a thin plastic packaging film and is shrunk over the filled carton by heating the same.  
  8. The method of claim 7 wherein the sleeve is placed over the assembled containers with the assembled containers in an inverted position and the bottom is thereafter applied while the sleeve and containers remain in an inverted position.  
  9. The process of claim 8 wherein the film is a plastic packaging film adapted to shrink upon the application of heat, and heat is applied to the film after being wrapped over the package to thereby shrink the same onto the carton and the sleeve and the bottom portion of the carton are both applied while the contents of the carton are in an inverted position.  
  10. The method according to claim 9 wherein the carton bottom is applied by providing a slide for the carton bottom to slide under the influence of gravity to a predetermined position, the carton is advanced beneath this predetermined position with the contents thereof extending upwardly in a position adapted to engage one inside edge of the carton bottom while in said predetermined position and thereby withdraw the carton bottom from slide allowing the carton bottom to come to rest on top of that portion of the contents within the sleeve extending from the end thereof.  
 UNITED STATES PATENT @FFICE CERTIFICATE OF CORRECTION 1 5 3,878 ,943 Dated April 22 97 Jack A. Ryan et al Patent No.  
 Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:  
 Columns 6 and 7 claim 6 should appear as shown below:  
 6 A method of forming a shipping carton comprising the steps of providing a tubular sleeve composed of stiff fibrous packaging material and having at least four fold lines running from one edge to the other in paralled relationship, providing a carton bottom having a rectangular bottom panel and four vertically extending side walls bonded together at their adjacent edges assembling the containers to be placed in the package in a group having a predetermined height, width and length, establishing relative motion between the sleeve and the containers to slide the sleeve onto the group thus assembled until the group of containers is enclosed thereby and is retained in an assembled relationship with the ends of the containers projecting from one end of the sleeve thereafter placing the carton bottom over the projecting ends of the cartons that FORM PO-1050 (10-69) USCOMM-DC 60376-1 69 U.5i GOVERNMENT PRINTING OFFICE: 8 9 93 o UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 878 943 Dated April 22 1975 Jack A. Ryan et a1. Page 2 Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:  
 project from the sleeve while they are retained in the assembled containers in their assembled condition and shrinking a plastic film thereover to press the sleeve against the vertically eictending side walls of the bottom portions of the carton thereby strengtheiiing the walls of the carton formed by the combination sleeve and panels to provide a compressive strength substantially in excess of the same two piece carton without the film shrunk thereover.  
 Column 8, claim 10 should appear as shown below:  
 10. The method according to claim 9 wherein the. carton bottom is applied by providing a slide for the carton bottom to slide upon under the influence of gravity to a predetermined position, the assembled containers are advanced beneath said predetermined position with their FORM PO-IOSO (10-69) USCOMM-DC 60376-1 69 U.$ GOVERNMENT PRINTING OFFICE: 869- 93 0 Patent No. 3,878,943 Dated April 22, 1975 Jack A. Ryan et a1 Page 3 Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:  
 ends extending upwardly in a position adapted to engage one inside edge of the carton bottom while in said predetermined position and thereby withdraw the carton bottom from said slide allowing the carton bottom to come to rest on top of that portion of the containers within the sleeve eQ ctending from the end thereof.  
 Signed and Scaled this twenty-ninth Day Of July 1975 [SEAL] A ttesr:  
 RUTH c. MASON C. MARSHALL DANN Arresting Officer (&#39;mnmisxinner of Patents and Trazlwnurks FORM PO-1050 (10-69) USCOMM-DC sows-P69 U.S. GOVERNMENT FRINTING OFFICE: o