Abstract:
A one piece tamper-evident paperboard carton having overlapped end flaps secured to each other in such a way that the ends of the carton cannot be opened without tearing the paperboard so that observation of the carton would indicate that it had been previously opened.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to folding cartons, and more particularly to a carton having closure means which prevents the carton from being opened without at least a partial destruction of the integrity of the carton to indicate that it has been opened. 
     2. Description of the Prior Art 
     A prior art search conducted in the United States Patent and Trademark Office and directed to the subject matter of this application disclosed the following United States Letters Patent: 
     
         ______________________________________RE. 23,670     3,893,614    3,724,741                           3,511,4313,095,135 2,485,235    2,041,932______________________________________ 
    
     None of the prior art patents uncovered in the search discloses an end loading top opening carton wherein the closure means at each end of the carton includes a novel intermediate flap arrangement like that of the present invention which permits the carton to be partially glued by the manufacturer, filled by the packer, and then sealed by the packer in such a manner that any subsequent attempt to open the carton would be apparent because of physical damage to the carton. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to provide, in an end loading, end opening, paperboard carton, a closure arrangement for each end of the carton which prevents the carton from being opened without at least a partial destruction of the integrity of the carton. 
     Another object of the invention is the provision, in a carton of the type described, of a closure arrangement which will permit the manufacturer to partially glue the carton before shipping to the packer, so that one end of the carton can be closed sufficiently to permit the packer to load the carton and then further close and seal both ends of the carton. 
     These and other objects of the invention will be apparent from an examination of the following description and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of the inner surface of a blank of foldable sheet material from which the carton illustrated in the other views may be formed; 
     FIGS. 2, 3, and 4 are views similar to FIG. 1, but illustrate various sequential steps in the folding operation by which the carton is formed; 
     FIG. 5 is a fragmentary perspective view of a carton embodying features of the invention, which has been erected but before the ends thereof have been closed; 
     FIG. 6 is a view illustrating a portion of the structure shown in FIG. 5, but with one end of the carton shown in a more advanced stage of closing; 
     FIG. 7 is a perspective view of a closed and sealed carton embodying features of the invention; and 
     FIG. 8 is a fragmentary view similar to FIG. 1, but illustrating the manner in which one end of the carton may be opened. 
    
    
     It will be understood that, for purposes of clarity, certain elements may have been intentionally omitted from certain views where they are believed to be illustrated to better advantage in other views. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings for a better understanding of the invention, it will be seen that the carton, indicated generally at C and illustrated at FIGS. 5-8, may be formed from the unitary blank B of foldable sheet material illustrated in FIG. 1 of the drawings. 
     The main portion or body of the carton includes a first side wall panel 10, a second or rear side wall or panel 12, a third side wall panel 14, a fourth or front side wall panel 16, and a glue panel 18, all of which are foldably joined to each other along parallel fold lines 13, 15, 17, and 19, respectively, to form a tubular structure open at the ends. 
     The closure means at one end of the carton, usually the lower end if the carton is filled from the top, is illustrated at the left sides of FIGS. 1-4. This closure arrangement includes an intermediate closure flap 30, foldably joined along a weakened tear line 31 to an adjacent edge of first side wall panel 10; an outer closure flap 32, foldably joined along a fold line 33 to an adjacent edge of second side wall panel 12; and an inner closure flap 34 comprising a pair of generally triangular first and second sections 34a and 34b, respectively, which is foldably joined along a fold line 35 to an adjacent edge of third side wall panel 14. 
     Inner closure flap first and second sections 34a and 34b are foldably joined to each other along a diagonal fold line 37. Second flap section 34b has foldably joined to a side edge thereof, along a fold line 39, a retaining flap or panel 38. 
     A tuck flap 40 is foldably joined to the outer edge of outer closure flap 32 along a weakened line of tear 41. 
     Now turning to the right hand sides of the views of FIGS. 1-4, it will be seen that the closure arrangement for the other end of the carton includes an intermediate closure flap 20, foldably joined along a weakened tear line 21 to an adjacent edge of first side wall panel 10; an outer closure flap 22, foldably joined along a fold line 23 to an adjacent edge of second side wall panel 12; and an inner closure flap 24, foldably joined along a fold line 25 to an adjacent edge of third side wall panel 14. 
     Inner closure flap 24, has foldably joined to a side edge thereof, along a fold line 27, a tuck tab 26. A tuck flap 28 is foldably joined along a weakened line of tear 29 to the outer free edge of outer closure flap 22. 
     As previously indicated, the carton, after being formed by the manufacturer, is shipped to the user or packer in a flat, partially glued condition, as illustrated in FIG. 4. 
     In the formation of the carton, referring now to FIG. 2, it will be seen that the second or outer section 34b of inner closure flap 34 is folded 180 degrees to overlie first section 34a with retaining flap 38 overlying an end area of third side wall panel 14. 
     An adhesive, indicated generally at MG, is applied to outer surface of retaining flap 38, so that when fourth side wall panel 16 is subsequently folded 180 degrees to overlie retaining flap 38 and third side wall panel 14, retaining flap 38 will be secured to fourth side wall panel 16. 
     Another strip of adhesive, also indicated generally at MG, is applied by the manufacturer to the outer surface of glue panel 18 and extensions 18a, so that when first side wall panel 10 is folded 180 degrees to overlie glue panel 18 and second side wall panel 12, glue panel 18 will be secured to first side wall panel 10 and extensions 18a to respective inner closure flaps 20 and 30, to form a tubular structure. 
     When the packer receives the carton from the manufacturer, it is in the collapsed condition illustrated in FIG. 4. As best seen in FIG. 5, the novel bellows arrangement created by the two sections 34a and 34b, which are foldably joined to each other along diagonal fold line 37, causes the inner flap to close the end of the carton as the carton is moved from collapsed to erected condition. The purpose of having this inner flap in such a position is to permit the packer to load a product from the other end of the carton. The inner flap will hold the product in the carton until the outer closure flaps have been secured in position. 
     Prior to closing the lower end of the carton as illustrated in FIG. 5, the tuck tab 26 is folded at right angles to the inner closure flap 24, so that when the inner closure flap 24 is folded at right angles to the center side wall panel 14, the tuck tab will be positioned against the inner surface of fourth side wall panel 16, as illustrated in FIG. 6. 
     For the final closing and sealing of the carton, adhesive indicated generally at PG is applied by the packer to the inner surfaces of both of the outer closure flaps 22 and 32 and related tuck flaps 28 and 40. 
     The closure flaps are folded over into overlapping relation with related inner and intermediate closure flaps and secured thereto. At the same time, tuck flaps 28 and 40 are folded over and tucked into the carton behind the carton side wall panel and respective tuck tab 26 and retaining flap 38 and secured to the outer surfaces thereof. 
     It will be noted that the areas at the corners of the carton where the outer closure flaps 22 and 32 are joined to their respective tuck flaps 28 and 40 are free from glue. It will also be noted that the outer closure flaps are joined to their respective tuck flaps by weakened lines of tear. The purpose of this is to make it extremely difficult to attempt to open either end of the carton without breaking one of the weakened lines of tear in such a way as to indicate that the carton has been opened. 
     When it is desired to open the carton, outer closure flap is 22 torn away, as illustrated in FIG. 8, and inner closure flap 24 pulled up to expose and make available the contents of the carton. 
     Thus, the carton provides a novel closure flap arrangement which makes it easy for the packer to fill the carton and then seal it in such a way as to prevent the opening of the carton without the partial destruction of the integrity of the carton. This is extremely important in cartons for pharmaceutical and other products designed for human consumption.