Abstract:
A shipping carton is converted to use as a display carton using perforated lines and precut openings that together define a line circumscribing the carton. At any location at which the perforated line crosses an edge of the carton of another perforated line, a precut opening provides a clean separation. Additionally, no section of the perforated lines parallels an adjacent fold line.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Technical Field  
         [0002]     The present invention relates generally to a shipping and display carton. More specifically, the invention relates to a slipping carton, and a method of making a shipping carton, that is easily transformed into a display carton having neatly severed walls.  
         [0003]     2. Description of Related Art  
         [0004]     Millions of dollars are spent each year in packaging products for transportation from the manufacturer to the store. Rather than require these products to be removed from the container and individually placed on shelves, it has long been desirable to ship products in cartons that can quickly be converted to provide a display format. Because of the variety of products and their differing needs, many different types of shipping and display cartons have been made. Examples of combination shipping and display cartons can be found in U.S. Pat. No. 2,152,079 to Mott, U.S. Pat. No. 3,315,875 to Praetorius, U.S. Pat. No. 4,000,811 to Hardison et al., and U.S. Pat. No. 5,826,728 to Sheffer, to name a few, all of which are incorporated by reference. Each of these patents attempts to provide a convertible carton that will provide adequate protection for its contents during shipping, then transform into an aesthetic display carton.  
         [0005]     By far the most common material used for shipping/display cartons is corrugated cardboard. This material is strong, lightweight, relatively inexpensive, and recyclable. When converting a corrugated shipping carton into a display carton, it would be desirable to have a carton that is easy to open, yet presents a pleasing appearance without inadvertent tears. Several means already exist that attempt to achieve this goal, although all have drawbacks. These drawbacks will be further explained using an exemplary carton, shown in  FIG. 1   a.    
         [0006]      FIG. 1A  shows a prior art design for a shipping and display carton  100  that has the shape of a rectangular prism measuring about 9¼×19½×9½ inches. The carton has four solid sides: top and bottom panels  110  and two end panels  120 . Two short flaps  130  extend from the end panels  120  and two long flaps  140  extend from top and bottom panels  110 . The two long flaps  140  are sized so that they do not meet to completely close the box; rather, all the flaps  130 ,  140  together frame an opening  150  in the carton, with overlapping flaps  130 ,  140  in each corner.  
         [0007]     Tape can be wrapped from the long flaps  140  to the ends  120  to seal and stabilize the carton, or the overlapping flaps  130 ,  140  can be glued or otherwise fastened together to seal the carton.  
         [0008]     This carton design is used for shipping lightweight containers of snack foods, such as chips. To convert the carton to display, the stocker removes the top half or two-thirds of the carton by cutting a line completely across each of the short flaps  130  and end panels  120 . This creates a tray  150  having short edges that hold the product in place yet provide high visibility to consumers.  FIG. 1B  presents an idealized conversion to a display carton  100 ′ with perfectly straight edges that neatly bisect panels  120  and  130  to create shortened sides  120 ′ and  130 ′. The ability to make this neat of a transformation is desirable, but rarely obtainable. Often, the person stocking the product is in a hurry, so the actual cuts are rarely this straight or this neat. Further, the stocker must carry a knife and must take care not to cut the product during the process of converting the carton to display. In other carton designs, extra layers of cardboard are sometime included beneath the cut lines; these layers are used to protect the product during cutting, but add to the expense.  
         [0009]     One alternative to cutting the carton is to use special tear strip tapes, such as those offered by 3M Corporation. These tapes can be used to make an easy-to-open carton that has a neat appearance, but they add significantly to the cost of the carton.  
         [0010]     A third alternative is to provide perforations in the cardboard itself so that sections of the carton can be quickly removed for display. This method is inexpensive, but has problems of its own.  FIGS. 2   a  and  2   b  are taken from U.S. Pat. No. 3,315,875 to Praetorius and demonstrate a prior art method of turning a shipping carton  200  into a display carton  200 ′. Perforated lines  202  make a U-shape, defining a removable strip  204  that includes the larger flap  206  of the lid.  
         [0011]     Additional perforated lines  208  allow the smaller flaps  210  to be removed, creating the open display carton  200 ′. However, it can be difficult to obtain a clean tear. This is especially true at the edges of the carton, where the tear has to turn a corner. The strength of the cardboard is enhanced by the adjacent wall, so additional force is needed to tear. At the same time, the direction of the force needs to change abruptly; it is difficult to provide the extra force in a controllable manner. Too often tearing across a corner results in ragged edges that are less appealing. Additionally, the perforations create weakened sections of the carton that can accidentally tear, often when the package is being assembled. The carton of  FIG. 2   a  is exemplary of this. When the blank is being folded to form the carton, care must be taken when making the vertical folds  212 ; otherwise the cardboard may accidentally fold along the weakened line of perforations  202 , further weakening the line of perforations  202  and causing premature tearing. Likewise, the folds at the base of flaps  210  are weakened by the perforated lines  208 . The pre-mature removal of the flaps  210  would leave a gap in the shipping carton  200 . Because of these problems, this method has thus far proved to be inexpensive but less than ideal.  
         [0012]     Consequently, it would be desirable to have a carton that is easily convertible from a shipping carton to a display carton, presents a neat, pleasing appearance for display, does not tear prematurely, requires no tools, and adds little or nothing to the cost of making the carton.  
       SUMMARY OF THE INVENTION  
       [0013]     Difficulties with using perforated lines to remove sections of a carton are related to two problem areas. 1) having a line of perforations that parallel a nearby folding line and 2) the difficulty in tearing a perforated line that crosses an edge of the carton. In recognizing these problem areas, the invention sets as design criteria that a) no perforated line should parallel an adjacent fold line in the design and b) if a line of perforations crosses an edge of the carton, a precut opening should be provided at the juncture.  
         [0014]     With these design criteria, it is possible to design a carton that meets all the desirable criteria discussed. The carton can be converted to display by removing one or more sections of cardboard bounded by perforated lines, using no tools. The difficulty in tearing around edges of the carton is removed by the pre-cut openings, permitting a neat, pleasing appearance. Because the perforated lines do not parallel adjacent fold lines, premature tearing is lessened or eliminated. Finally, this is a change in design that does not add to the cost of manufacturing the carton.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein:  
         [0016]      FIG. 1   a  depicts a prior art design for a shipping and display carton;  FIG. 1   b  shows an idealized version of that same carton after conversion to display;  
         [0017]      FIGS. 2   a  and  2   b  depict a prior art carton having perforations to aid in separating sections of the carton;  
         [0018]      FIGS. 3   a  and  3   b  depict two views of a shipping and display carton according to a preferred embodiment of the invention,  FIG. 3   c  shows the carton of  FIG. 3   a  and  3   b  after conversion to a display carton;  
         [0019]      FIG. 4  depicts the layout for the shipping and display carton of  FIGS. 3   a  and  b;  and  
         [0020]      FIG. 5  depicts a shipping and display carton according to an alternate embodiment of the invention.  
     
    
     DETAILED DESCRIPTION  
       [0021]      FIGS. 3   a  and  3   b  show a shipping and display carton according to a preferred embodiment of the invention. This carton  300  has the same basic shape as the prior art cartons  100  of  FIGS. 1   a  and  1   b,  but uses the guidelines set forth above, namely that a) no perforated line should parallel an adjacent a fold line in the design and b) if a line of perforations crosses an edge of the carton, a precut opening should be provided at the Juncture. Unless otherwise noted, identical element numbers used in common between drawings are to substantially similar elements in the drawings. As seen in  FIGS. 3   a  and  3   b,  which are views from opposite ends of the carton, perforated line  332  runs from one edge  335  of the flap  130  almost to the edge  337  of the carton, where it terminates in a precut hole  350 . The precut holes  350  wrap around the corner, so that there is no need to tear around a corner, the most common place for an accidental tear to happen. Perforated lines  322  run from each of four precut holes  350  to meet in another precut hole  355  in the center of the end panel  120 . In this embodiment, the precut holes  350 ,  355  each have a width that ranges from ¼ to ⅝ inches and a length of 2/4 inches. A stocker need only grab the edge  335  of flap  130  and pull to quickly and cleanly separate section A from the rest of the carton. Four such moves and each of the corresponding sections B, C, D is removed, leaving the lower portion of the carton as a display tray  300 ′, as seen in  FIG. 3   c.    
         [0022]     In order to keep the tears along the perforated lines clean, the perforations and lands (spaces between the perforations) should both be in the range of ⅛ to ½ inches each. In the specific embodiment shown, the perforations are 1 inch, while the lands are 3/16 inch. Additionally, at the beginning of each perforation line, the beginning perforation is longer, in the range of ½ to 1 inch in length, to be sure that the tear starts well. In the embodiment shown, the leading perforation is ¾ inch. These dimensions allow the cardboard to tear neatly, but provide enough strength to the carton that it will remain intact during shipping.  
         [0023]     A blank for a corrugated cardboard box refers to the flat sheet of cardboard that has been cut into a necessary design and scored so that it will fold most easily along the desired lines. A blank is formed by a rotating die that can cut, score for fold lines, and perforate a sheet of corrugated cardboard in a single pass.  FIG. 4  depicts a blank that can be assembled into the carton of  FIG. 3   a.  Since all cuts and folding lines are made at the same time, the addition of the perforated lines and precut holes does not affect the cost of production. A manufacturer switching from making the box of  FIG. 1   a  to the box of  FIG. 3   a  would have to have changes made in the die used to make the boxes, but no additional costs beyond the die. As can be seen from  FIG. 4 , this is a purposefully simple design. Long fold lines  302  run the length of the pattern, between the flaps  130 , 140 , and the body  110 ,  120 ′. From this perspective, it is clear that none of the perforated lines parallel “adjacent” fold lines. For the purposes of this disclosure, fold lines are considered “adjacent” to perforated lines if they are not separated from the perforations by a cut or other fold line. Thus, perforation lines  332  run parallel to the fold lines  304 , but these lines are not adjacent. Each fold line  304  terminates at a cut  306  and is separated from perforation lines  332  by a cut  306  and a fold line  302 . Fold lines  302  are perpendicular to the perforation lines  232 .  
         [0024]      FIG. 5  shows a shipping and display carton  500  according to an alternate embodiment of the invention. This design has perforation lines  332  and precut holes  350  on flap  130 ′, but the perforated lines  422  on end panel  120 ″ curve up and down, similar to a sine wave. In such a manner, the perforated lines  422  are not parallel to the edges of the carton, which are formed at fold lines  304 .  
         [0025]     Two specific embodiments of the invention have been disclosed. However, one of ordinary skill in the art will recognize that one can modify the dimensions and particulars of the carton, as well as the specific design of the perforated lines, without straying from the inventive concept.