Abstract:
A carton particularly well suited for storing packaged dry goods is designed such that the closure flaps that close a top opening of the carton do not obstruct the loading of goods into the carton through the top opening when the carton is placed on its side. The carton includes a front and rear panel that bow slightly outwardly so as to apply tension to the closure flaps connected to the front and rear panel. This tension prevents the flaps from falling into the opening during loading of the carton. This tension is created by vertical score lines in the front and rear panels as well as their associated closure flaps. In this regard, the mechanism to hold the closure flaps open is integrally formed with the carton.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Ser. No. 60/970,014, filed Sep. 5, 2007, the disclosure of which is incorporate herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to reusable storage containers and, more particularly, to a reusable corrugated or cardboard carton formed from a blank scored to have a series of folding lines along which the blank may be folded to erect the carton, and well-suited for storing dry goods such as packaged foodstuffs. 
     BACKGROUND OF THE INVENTION 
     Corrugated or cardboard cartons are commonly used for storing and transporting dry goods such as packaged foodstuffs. A typical carton has a set of top panels, a set of bottom panels, and a set of wall panels extending between the top panels and the bottom panels. When erecting the carton, the blank is folded along the score lines between the wall panels thereby resulting in an open-ended, generally rectangular container. The bottom panels are then folded inwardly, and in some cases frictionally held together, to close the bottom end of the container. In one representative type of packaging process, such a partially erected carton is laid on its side on a conveyor belt or track and then loaded from the side with packaged foodstuffs, such as snack chips, or other goods. Once loaded, the carton is rotated upright and the top panels are folded inwardly to close the top opening of the carton. 
     For an initial loading with such a packaging process, the top panels are not folded at their score lines until after the carton is loaded. Because of the rigidity of the blank, the top panels are generally in-line with the wall panels and thus do not block the top opening of the carton. However, after the top panels are folded after the initial loading, the aforementioned rigidity is lost and the top panels tend to sag into the interior of the carton. As a result, when the cardboard carton is reused, the top panels may block the opening into the carton and ultimately be pushed inwardly into carton as the carton is loaded. Since the carton is designed to be reused numerous times, the top panels become weakened with each use and therefore sag further with each use. One known solution is to use tape to maintain the top panels in an open position by temporarily adhering the top panel to the side panels. While effective in keeping the opening into the carton cleared, the use of tape or other mechanical means requires additional labor, cost and may even cause damage to and hasten the end of the life cycle of the carton. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a carton having a generally rectangular footprint that is defined in part by a pair of arcuate wall panels adjacent a pair of closure flaps. The wall panels are segmented from the closure flaps by horizontal score lines that also define the folding axes for the closure flaps. In addition to the horizontal score lines, a pair of vertical score lines extend from a base of the wall panels to a top edge of the closure flaps. The vertical score lines define flex points for the wall panels and the closure flaps to bow slightly outward and impart tension on the wall panels and the closure flaps. This tension effectively counters the fatigue of the closure flaps typically associated with repeated use of the carton, thereby allowing the carton to be repeatedly used with less risk of the closure flaps blocking the opening into the carton or being pushed inwardly into the carton as the carton is loaded. 
     Therefore, it is an object of the present invention to provide a carton having a usable life exceeding that of conventional cartons. 
     It is another object of the invention to provide a reusable carton that presents an opening for subsequent loading that is generally equal to the opening that was presented for loading when the carton was initially loaded. 
     In it another object of the invention to provide a paper-based carton formed from a blank and constructed to counter the effects of fatigued closure flaps so that there is less likelihood that the closure flaps will obstruct the opening to the carton during loading of the carton. 
     Various other features and advantages of the present invention will be made apparent from the following detailed description and the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings illustrate the best mode presently contemplated of carrying out the invention. 
       In the drawings: 
         FIG. 1  is an isometric of an opened carton according to an embodiment of the present invention; 
         FIG. 2  is a side elevation view of the carton shown in  FIG. 1 ; 
         FIG. 3  is a bottom plan view of the carton shown in  FIG. 1 ; 
         FIG. 4  is an isometric view of the carton shown in  FIG. 1  with the cardboard carton lying on its side; and 
         FIG. 5  is an isometric view of the carton of  FIG. 1  after being broken down to lie flat; and 
         FIG. 6  is a top plan view of a blank from which the carton of  FIG. 1  can be made according to one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A container or carton  10  constructed in accordance with the present invention is shown in  FIGS. 1-4 .  FIG. 1  shows the carton  10  partially assembled such that a top opening through which goods, such as packaged foodstuffs, may be loaded.  FIG. 2  is a side elevation view of the carton  10  and  FIG. 3  is a bottom view of the carton  10 . As will be described in greater detail below, when used with one type of packaging process, the carton is laid on its side for loading thereof, such as illustrated in  FIG. 4 . 
     The carton may be made from a one piece blank  12 , shown in  FIG. 6 , of corrugated board, cardboard, paperboard, or other suitable, foldable sheet material. The carton  10  has a front panel  14 , a back panel  16 , and a first side panel  18  located between front and back panels  14  and  16 , and defined by vertical fold lines  20  and  22 . An inner side tab  24  extends from the back panel  16  at a vertical fold line  26 , and a second side panel  28  extends from front panel  14  at a vertical fold line  30 . The upper and lower edges of the panels  14 ,  16 ,  18 ,  28  are defined by a continuous upper horizontal fold line  32  and a lower, substantially horizontal, fold line  34 . “Upper” and “lower” define the position of the fold lines when the carton is erected rather than when in the position shown in  FIG. 6 . 
     Second side panel  28 , front panel  14 , first side panel  18 , and back panel  16  each have upper and lower closure flaps extending from the upper  32  and lower  34  horizontal fold lines, respectively. Specifically, second side panel  28  includes a rectangular upper closure flap  36  and an irregular lower closure flap  38 . Front panel  14  includes rectangular upper and lower closure flaps  40 ,  42 , respectively. Lower closure flap  42  includes a cut-out tab-receiving portion  43 . First side panel  18  includes an upper closure flap  44  having beveled corners  45   a ,  45   b  and an irregular lower closure flap  46 . Back panel  16  includes a rectangular upper closure flap  48  and a lower closure flap  50  having angled edges  51   a ,  51   b  ending at a bottom closure tab  52 . Upper closure flaps  40 ,  48  also include first and second cut-out receiving portions, or slots,  49   a ,  49   b  configured to receive the beveled corners  45   a ,  45   b  of closure flap  44 . 
     The vertical dimension v U  of the upper rectangular closure flaps  36 ,  40 ,  44 ,  48  is approximately half of the horizontal dimension h S  of the side panels  18 ,  28  while the vertical dimension v L  of the lower closure flaps  38 ,  42 ,  46 ,  50  is approximately two thirds the horizontal dimension h S . As shown in  FIG. 4 , when erected into a carton  10 , lower closure flaps  38 ,  46  are folded over and overlapped by lower closure flaps  42 ,  50 . The bottom closure tab  52  is inserted into the tab-receiving portion  43  to securely close the bottom of the carton  10 . To close the top of the carton  10 , upper closure flap  36  is folded over and overlapped by upper closure flaps  40 ,  48 . Flap  44  is then folded over flaps  40 ,  48  with corners  45   a ,  45   b  inserted into cut-outs  49   a ,  49   b  to securely close the upper flaps. 
     The upper and lower fold lines  32 ,  34  are formed by creating a score in the blank  12  as is known in the art. The upper fold line  32  is a straight line extending throughout the length of the blank  12 . As shown in  FIG. 1 , the lower fold line  34  has two distinct arcuate, or curved, score sections  54  located between the front and back panels  14 ,  16  and their respective lower closure flaps  42 ,  50 . The front and back panels  14 ,  16  further contain vertical scores  56  extending through their respective upper closure flaps  40 ,  48 . 
     In erecting the carton  10  from the blank  12  as described, panels  14 ,  16 ,  18 ,  28  are folded about fold lines  20 ,  22 ,  26 ,  30  to form a rectangular tube in which second side panel  28  overlaps inner side tab  24 . Glue or another suitable adhering means, is applied to the overlap so as to fixedly secure the facing surfaces of inner side tab  24  and side panel  28  together. In order to close the bottom of the carton, lower panel closure flaps  38 ,  46  are first bent inwardly as described above. Lower flap  42  and tapered flap  50  are then bent inwardly such that retaining tab  50  is engaged within the tab-receiving portion  43  of lower closure flap  42  and held via a friction fit, as shown in  FIG. 3 . After the carton  10  has been loaded, upper closure flap  44  is bent inwardly over upper closure flaps  40 ,  48  which are folded over closure flap  36  as described above. The beveled corners  45   a ,  45   b  of upper closure panel  44  are inserted into slots  49   a ,  49   b  and held via a friction fit to securely hold the upper closures flaps  36 ,  40 ,  44 , and  48  closed. 
     Before the carton  10  is used for the first time, a user initially erects the carton  10  as described above, except for the top closure flaps  36 ,  40 ,  44 ,  48 . When lower closure panels  38 ,  42 ,  46  and  52  are folded, the two curved sections  54  in the bottom fold line  34  create tension that is transmitted to the front and back panels  14 ,  16  and respective upper closure flaps  40 ,  48 . The tension in the panels  14 ,  16  is experienced by the vertical scores  56 , which causes the front and back panels  14 ,  16  and upper closure flaps  40 ,  48  of the carton  10  to bow slightly outward, creating a shallow V-shaped configuration of the front and back panels  14 ,  16  and respective upper closure flaps  40 ,  48 . This bowing action causes the upper flaps  40 ,  48  to stiffen and remain erect when the carton  10  is placed on its side, as illustrated in  FIG. 4 , in a position in which either the front or back panel  14 ,  16  faces downwardly. The bottom curved score sections  54  are shaped in a generally arcuate manner such that sufficient tension is provided to keep the upper closure flaps  40 ,  48  erect while still maintaining an essentially rectangular footprint for the assembled carton  10 . A user may, either manually or via automated machinery, fill the partially assembled carton  10  with items without interference from the upper flaps  40 ,  48  and without the need for tape or any other mechanical means. The carton  10  may be repeatedly erected, filled, shipped, and unloaded, and then broken down, as shown in  FIG. 5 , to a flat configuration and returned for subsequent erection and filling, while still providing the ability to maintain the upper flaps  40 ,  48  in a self-supporting open condition during the filling operation. 
     While the invention has been shown and described with respect to a specific embodiment, it is contemplated that certain details may vary from the specific construction as disclosed, while still falling within the scope of the present invention. For example, the lower fold line  34  may have only one curved score section  54 , e.g., between front panel  14  and flap  42  and one vertical score  56  extending from the curved score  54  across the front panel  14  and upper closure panel  40 , while remaining within the scope of the present invention. 
     In addition, while the score sections  52  are illustrated as being arcuate, it is also understood that the score sections  52  may have a shallow V-type configuration formed by a pair of linear scores, or may have any other non-linear configuration. 
     The present invention has been described in terms of the preferred embodiment, and it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appending claims.