PATENT ABSTRACT
A carton assembled from a foldable blank including a base having a bottom panel and a plurality of walls and a lid having a top panel and a plurality of walls. The carton may include a tab extending from one of the plurality of walls of the base. The lid may have a slit defined proximate a fold line, the fold line being where at least one of the plurality of walls of the lid meet the top panel, and the slit may be adapted for receiving all or part of the tab therethrough. The lid may also have a slot disposed on the top panel and inward of the slit. After being received through the slit, the tab can be folded about the fold line to lie substantially parallel to the top panel of the lid and a distal end of the tab may be inserted into the slot.

PATENT DESCRIPTION
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/830,725, filed on Jun. 4, 2013, to Robert L. Fairchild, Jr., entitled “Clamshell Carton with Locking Tab,” the entire disclosure of which is hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is directed toward an improved clamshell carton which may preferably be made of paperboard or similar materials. Such clamshell cartons are often used in the fast food industry to contain and serve food items. However, such clamshell cartons may be made from other materials and may have many alternative uses. 
       BACKGROUND OF THE INVENTION 
       [0003]    Foldable clamshell cartons are used in the packaging industry with prolific use in the fast food industry. Foldable clamshell cartons constructed of paperboard are becoming more popular due to the fact that they can be shipped in an unfolded state and assembled on premises, are lighter weight, and/or consume less shipping volume. These characteristics may individually or collectively reduce manufacturing and/or shipping costs. Current foldable clamshell cartons usually have a catch arranged between the free edges of the front panels of the lid portion and the base portion. The catch may be positioned in the corners or the middle of the front panels and at a location where the lid portion otherwise overlaps or meets with the base portion. These catches are typically sufficient to keep the lid portion from becoming disengaged with the base portion when the carton is not being handled. However, the lid portion and the base portion often become spontaneously disengaged due to residual elastic forces present in the material if the folds are not fully completed or become deformed. Further, the lid portion often disengages the base portion causing spillage of the contents of the carton upon applying a lifting force to the lid or a constricting force upon the sidewalls to grip the carton, such as the forces required to remove the carton from a paper or plastic bag. 
         [0004]    Thus, there is a need in the art to provide a foldable clamshell carton having an improved locked position to prevent the disengagement of the lid portion from the base portion during handling and transport of the foldable clamshell carton and the contents thereof. 
       SUMMARY OF THE INVENTION 
       [0005]    The present application is directed toward a clamshell carton assembled from a foldable blank. The carton includes a base and a lid. The base generally includes a bottom panel and a plurality of walls extending upwardly therefrom when the carton is in an assembled and closed position. The lid generally includes a top panel and a plurality of walls extending downwardly therefrom when the carton is in an assembled and closed position. In one embodiment, the carton may include four walls. However, other embodiments may include other wall configurations, such as three walls or more than four walls. 
         [0006]    The base may include a tab extending from one of the plurality of base walls. The tab may generally have a width and a length and may have the shape of a trademark or logo of a retailer. The transition between the wall and the tab may be defined by a score line. The score line may make it easier to fold the tab relative to the wall. The length of the tab may be defined from the score line to the distal end of the tab, wherein the length may be greater than, less than or equal to a distance from a trailing edge of a front panel of the lid normal to the fold line between the front panel and top panel of the lid. The base may further include a height of its front panel being substantially similar of the sum of a height of a rear panel of the base and a height of a rear panel of the lid. 
         [0007]    The lid and the base of the carton may each include a fold line present at the intersection of each of the walls with the respective top and bottom panels. The fold lines may be disposed on the foldable blank during manufacturing and allow the carton to be easily folded at those locations. The lid may also have a slit defined therein proximate one of the fold lines. The lid may also have a slot cut into the top panel inward of the slit. The slot may be parallel to the slit. The slot may be configured for receiving a distal end of the tab. 
         [0008]    The tab and the slit may be arranged on the foldable blank so that they align when the carton is in a folded position. The slit may be sized and adapted for receiving the tab therethrough to facilitate the retention of the lid in a closed position. In one embodiment, the tab is arranged on the front panel of the base and the score line may be located near or at the upper edge of the front panel of the base. The slit may be arranged proximate the fold line between the front panel and the top panel of the lid. The slot may be arranged parallel to and/or inward of the slit. However, the tab may be disposed on any of the walls of the base and the slit may be disposed proximate any fold line of the lid opposite the tab. 
         [0009]    In one embodiment, the front panel of the lid may include a window area defined therein. In another embodiment, the window area may correspond in shape with the tab to reduce waste when cutting out the foldable blank from the stock material. 
         [0010]    When the present carton is assembled, the carton may include a locked position, wherein the locked position includes the tab being received into the slit, the tab being folded at the score line, the tab being orientated substantially parallel to the top panel of the lid, and the terminal end of the tab received into the slot in the top panel of the lid. 
         [0011]    Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments and the accompanying drawing figures. 
     
    
     
       DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0012]    In the accompanying drawing, which forms a part of the specification and is to be read in conjunction therewith in which like reference numerals are used to indicate like or similar parts in the various views: 
           [0013]      FIG. 1  is a top perspective view of a clamshell carton with locking tab illustrating the carton in a closed and locked orientation in accordance with a first embodiment of the present invention; 
           [0014]      FIG. 2  is a top perspective view of a clamshell carton of  FIG. 1  illustrating the carton in an open orientation in accordance with a first embodiment of the present invention; 
           [0015]      FIG. 3  is a top perspective view of a clamshell carton with locking tab illustrating the carton in a closed and partially locked orientation in accordance with a first embodiment of the present invention; 
           [0016]      FIG. 4  is an enlarged top perspective view illustrating the locking tab and slot of the clamshell carton in accordance with a first embodiment of the present invention; 
           [0017]      FIG. 5  is a top plan view of a blank used to form a clamshell carton with a locking tab in accordance with a first embodiment of the present invention; 
           [0018]      FIG. 6  is a top plan view of a diagram illustrating a plurality of blanks as they may be cut from a single sheet or roll of paperboard in accordance with a first embodiment of the present invention; 
           [0019]      FIG. 7  is a top perspective view of a clamshell carton with locking tab illustrating the carton in a closed and locked orientation in accordance with a second embodiment of the present invention; 
           [0020]      FIG. 8  is a top plan view of a blank used to form a clamshell carton with a locking tab in accordance with a second embodiment of the present invention; and 
           [0021]      FIG. 9  is a top plan view of a diagram illustrating a plurality of blanks as they may be cut from a single sheet or roll of paperboard in accordance with a second embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. For purposes of clarity in illustrating the characteristics of the present invention, proportional relationships of the elements have not necessarily been maintained in the drawing figures. 
         [0023]    The following detailed description of the invention references specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The present invention is defined by the appended claims and the description is, therefore, not to be taken in a limiting sense and shall not limit the scope of equivalents to which such claims are entitled. 
         [0024]    Referring to the figures, one embodiment of the present invention is directed to a clamshell carton  10  having a tray or base  12  hingedly attached to a cover or lid  14 . As discussed in greater detail below, the carton  10  includes a unique latch or lock construction for retaining the lid  14  in a closed orientation relative to the base  12 . 
         [0025]    As shown in  FIG. 2 , the base  12  includes a bottom panel  16  from which a front panel  18 , rear panel  20  and opposing side panels  22  extend upwardly therefrom. Glue tabs  24  may be provided for adhesively joining the side panels  22  with the front and rear panels  18  and  20 . The lid  14  includes a top panel  26  from which a front panel  28 , rear panel  30  (see  FIG. 5 ) and opposing side panels  32  extend downwardly therefrom when top panel  26  is disposed opposite and above bottom panel  16  as shown in  FIG. 1 . Lid  14  may also include a plurality of glue tabs  34  extending from side panels  32  and/or front and rear panels  28 ,  30  for adhesively joining the side panels  32  with the front and rear panels  28  and  30 . Rear panel  30  of the lid  14  is foldably secured to the rear panel  20  of the base  12  by a hinge line  36 . 
         [0026]    As illustrated best in  FIGS. 2 and 5 , the locking construction of the carton  10  includes a tab  38  extending from an upper edge  40  of base front panel  18 . While shown as having a generally triangular or “A” shape, it will be understood that the tab  38  may be of any suitable shape and may be shaped to accommodate a recognizable trade symbol or artwork design  64 . A first cut or slit  42  is provided in top panel  26  proximate the fold line  44  joining the front panel  28  and top panel  26  of the lid  14 . A shown in  FIG. 5 , the width w s  of the slit  42  corresponds to the width w t  of the tab  38 , as shown in  FIG. 5 , and is at least wide enough to allow the tab  38  to extend substantially through the slit  42 . 
         [0027]    As demonstrated in  FIG. 1 , when the carton  10  is in a closed orientation, the tab  38  may extend through the slit  42 . The tab  38  can then be folded along its base at score line  46  (see  FIG. 5 ) such that the tab  38  lies generally parallel to the top panel  26  of the lid  14 . A distal end  48  of the tab  38  can then be inserted or tucked into a second cut or slot  50  formed into the top panel  26  of the lid  14 . As shown in  FIGS. 3 and 4 , the length I t  of the tab  38  is slightly longer that the distance d s  between the slot  50  and fold line  44 . 
         [0028]    As shown in  FIG. 5 , additional cuts  52  and  54  intersecting slot  50  may be provided so that when the tab  38  lies flat on the top panel  26 , a user may push the end  48  of the tab generally downwardly to effectuate the engagement or tucking of the end  48  of the tab  38  into the slot  50 . When the tab  38  is inserted into the slot  50 , the tab  38  acts as a strap to hold the lid  14  closed with respect to the base  12 . 
         [0029]    In one embodiment best shown in  FIG. 5 , the front panel  18  of the base  12  has a height h fb , that is approximately equal to the combined heights k rb  and h rl  of the rear panels  20  and  30  of the base  12  and lid  14  such that when the carton  10  is in a closed orientation, the top edge  40  of the front panel  18  extends to and is positioned generally against the fold line  44 . This positions the score line  46  of the tab  38  is the same general axis as the fold line  44  of the lid  14  thereby enabling the tab  38  to be pivotally folded downwardly at fold line  46  when the lid  14  is in a closed position. 
         [0030]    As further shown in  FIG. 5 , the carton  10  can be constructed from a flat blank of material that may be formed of paperboard or other suitable material.  FIG. 6  illustrates a layout diagram comprising multiple blanks  10 A and  10 B as they may be cut from a single sheet or roll of material. It will be understood that, depending on the width of the roll, either more or less than two blanks  10 A and  10 B may be positioned across the width of the roll. As shown in  FIG. 6 , the tab  38  of a trailing blank  10 B may be cut, at least partially, from the front panel  28  of the lid  14  of a leading blank  10 A. In one embodiment, the tab  38  is of a length I t  such that the leading edge  40  of a trailing blank  10 B abuts the trailing edge  56  of a leading blank  10 A in order to even further reduce or eliminate paper waste between the blanks  10 A and  10 B. 
         [0031]    It will be appreciated that the tab  38  can be shaped to represent or accommodate the printing of a trade symbol or artwork design  64  (represented for illustrative purposes by an “A” in  FIGS. 1 ,  2  and  5 ) of a particular food vendor. Further, because the tab  38  of one blank  10 B may be cut from the front panel  28  of the lid  14  of another blank  10 A, the front panel  28  may include a window area  58  defined therein. The window area  58  may correspond in shape with a distal portion of the tab  38 . The inclusion of window area  58  provides the ability to print an additional trade symbol or artwork design  66  on the front panel  18  of the base  12  that will be visible through this window area  58  as demonstrated in  FIG. 1 . Conversely, if such a window area  58  is not desirable, the tab  38  of a trailing blank  10 B need not be cut from the front panel front  28  of the lid  14  of a leading blank  10 A, thereby resulting in an uninterrupted surface in the front panel  28 . 
         [0032]      FIGS. 7-12  illustrate a second embodiment of a carton  100 , which is similar in nature to the carton  10  shown in  FIGS. 1-6 . As shown in  FIG. 7 , the shape and placement of the locking construction of carton  100  differs from that of carton  10 . For example, as shown in  FIG. 8 , the tab  38 ′ may be of a shorter length h. As shown in  FIG. 9 , the shorter length I t  allows the leading edge  40  of a trailing blank  100 B to abut the trailing edge  56  of a leading blank  100 A in order to reduce or eliminate paper waste between the blanks  100 A and  100 B when tab  38 ′ corresponds in shape with window  58 ′ as shown in  FIG. 9 . Accordingly, the distance d s  between the slot  50  and fold line  44  is reduced so that such distance d s  remains slightly less than the length I t  of the tab  38 ′ thereby permitting the end  48  of the tab  38 ′ to be inserted into the slot  50 . In addition, tab  38 ′ may have a wider width w t  so as to provide a wider extent of the hold down action provided by the locking mechanism of the present carton  100 . Additionally, as set forth above, the tab  38 ′ can be of any desired shape, including arc-shaped, as depicted in  FIGS. 7-10 . 
         [0033]    As shown in  FIG. 8 , the carton  100  may further include an anti-binding feature  60  and vents  62  that may be selectively opened or removed. As shown in  FIG. 8 , anti-binding feature  60  may include crossing slits  63  and  64  wherein the crossing slits intersect proximate hinge line  36 . As shown in  FIG. 8 , vents  62  may be circular cut-outs or perforated portions of the rear panel  30  of lid  14 . However, vents  62  may be disposed on rear panel  20  of base  12 , side panels  22  or  32 , front panels  18  or  28 , bottom panel  16 , or top panel  26 . 
         [0034]    Other and further embodiments of the present invention will also be appreciated. For example, the carton  10  or  100  may include more than one tab  38  or  38 ′, slit  42  and slot  50 , such that two or more locking mechanisms may be provided. In another embodiment, tab  38  or  38 ′ may extend from a side panel  22  rather than a front panel  18 . In a further embodiment, the tab  38  or  38 ′ may extend from the front panel  28  or a side panel  32  of the lid  14  and a slit  42  and slot  50  may be defined in the bottom wall  16  of the base  12 . In another embodiment, the present carton may comprise any number of walls extending from the top and bottom panel, with three walls being a common variation of the embodiments described above. The use of three walls allows for a triangular or pie-shaped carton. 
         [0035]    From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure. It will be understood that certain features and sub combinations are of utility and may be employed without reference to other features and sub combinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments of the invention may be made without departing from the scope thereof, it is also to be understood that all matters herein set forth or shown in the accompanying drawings are to be interpreted as illustrative and not limiting. 
         [0036]    The constructions described above and illustrated in the drawings are presented by way of example only and are not intended to limit the concepts and principles of the present invention. Thus, there has been shown and described several embodiments of a novel invention. As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present construction will, however, become apparent to those skilled in the art after considering the specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.