Patent Publication Number: US-4546912-A

Title: Carton lid with rounded corners

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to folding carton lids, and more particularly to a liquid-tight carton lid having rounded corners for use with a carton of a similar shape. 
     2. Description of the Prior Art 
     Applicant is unaware of any prior art patent that discloses a one-piece, liquid-tight, paperboard carton lid having an absolutely flat top wall with flat side and end walls and rounded corners formed in the manner of the present invention. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a one-piece paperboard carton lid having flat side and end walls joined to each other by rounded corners. 
     A more specific object of the invention is the provision, in a carton of the type described, of a liquid-tight corner construction. 
    
    
     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 perspective view of a carton lid embodying features of the invention, shown with a carton having a similar contour; 
     FIG. 2 is an exploded perspective view of the structure illustrated in FIG. 1; 
     FIG. 3 is an inverted perspective view of the carton lid illustrated in the previous views; 
     FIGS. 4 and 5 are views similar to FIG. 3 but illustrate different steps in the erection of the carton lid; and 
     FIG. 6 is a plan view of a blank of foldable sheet material from which the lid illustrated in the other views may be formed. 
    
    
     It will be understood that, for purposes of clarity, certain elements may have been intentionally omitted from certain views where there 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 novel lid, indicated generally at L in FIG. 3, may be formed from a unitary blank B of foldable sheet material, such as coated paperboard, illustrated in FIG. 6. 
     Lid L includes a main or top panel 10 having opposed straight side edges 11 and opposed straight end edges 13 which are connected to each other by rounded corner edges 15. 
     Connected to the sides of top wall panel 10 are a pair of side walls 20 each of which has a center portion 20a and a pair of end portions 20b. 
     The side walls each include an outer panel 22 which is foldably joined at its upper edge to top wall panel 10 along a related side edge 11 thereof. Each side wall outer panel 22 has foldably joined to its lower edge, along a fold line 25, an inner panel 24 which is folded 180 degrees about the fold line 25 so as to lie in face-to-face relation with the inner surface of the outer panel 22. 
     Each of the outer panels 22 has foldably joined to its upper edge, along a fold line 27, a retaining flange 26 which is disposed to be folded inwardly at right angles to the retaining flange so as to lie against the inner or lower surface of top wall panel 10 and be secured with respect thereto in any desired manner. 
     In order to permit the end portions 20b of the side walls to be folded around the corners of the top wall panel 10 so as to lie over the corner edges 15 there may be provided, in the area adjacent the corner edges of the top wall panel, a plurality of transversely extending scores 24a in side wall inner panels 24 and a plurality of transversely extending notches 26a in the retaining flanges 26. 
     At each end of the carton lid there is provided an end wall 30 which includes an outer panel 32 foldably joined at its upper edges to the related end edge 13 of the top wall panel 10. 
     Each end wall outer panel 32 has foldably joined to its lower edge, along a fold line 35, an inner panel 34. Each end wall inner panel 34 has in turn foldably joined to its upper edge, along fold line 37, a retaining flange 36 which is slightly longer than panels 32 and 34, because it has extensions 38 extending outwardly from the ends thereof beyond panels 32 and 34. 
     In erecting the carton lid L, the end portions of the side walls 20 are folded around the ends of the carton so as to overlie the top wall panel corner edges 15 and end edges 13 and be secured between the outer and inner panels 32 and 34 of the respective end walls 20. 
     The retaining flanges 36 of each of the end walls are disposed to be folded inwardly at right angles to the inner panels so as to lie against and be secured with respect to the inner or lower surface of top wall panel 10. 
     Thus, the end walls keep the end portions of the side walls in place and the scores and notches in the side walls permit them to be curved around to match the contour of the carton top wall and at the same time provide a liquid-tight corner construction for the carton lid.