Carton with improved opening structure

In a carton structure formed from paper board characterized by inclusion of a relatively narror wall portion to be opened in a controlled and predictable manner by tearing, the combination comprising:

• relatively narrow inner and outer flaps folded in overlying relation and adhered to one another along their lengths in formation of said wall portion;
• means defining a first cut score line along which said inner flap is folded to form an outside facing edge of the set up carton;
• means defining a second cut score line in said inner flap parallel to and intermediate said first cut score line and the free edge of said inner flap;
• said inner flap having a first upper surface portion bounded by said first and second cut score lines, a second upper surface portion bounded by said second cut score line and said free edge of said inner flap, said inner flap having a lower surface portion on the side opposite said first and second upper surface portions;
• the first upper surface portion of the inner flap being separable from the lower surface portion of the inner flap by delamination;
• and
• means defining a line of weakness in said outer flap coincident with and overlying said second cut score line, the recited adherence of said flaps to one another being in the region of the first upper surface portion between said cut score lines on said inner flap and between said line of weakness and the free edge of said outer flap;
• said outer flap being graspable at one end thereof in a region between said line of weakness and the corresponding free edge portion, and adapted to be pulled away from the lower surface portion and the second surface portion of the underlying inner flap to effect separation of the first upper surface of the inner flap from the second surface portion along the second cut score line and from the lower surface portion between the first and second cut score lines by delamination, the first surface portion of the inner flap remaining adhered to the outer flap during the delamination of the inner flap between said cut score lines, said first cut score line for facilitating said delamination of said inner flap, whereby said carton is opened;
• a notch disposed between said first and second cut score lines in one end of said inner flap, said notch being generally V-shaped and having one leg substantially aligned with said second score line and another leg intersecting the end of said inner flap at a point closely spaced from said first cut score line for ensuring initiation of delamination of said inner flap end in a region between said point and said first cut score line, said notch of the inner flap underlying said one end of said outer flap a sufficient distance from said one end of said outer flap to accommodate grasping said one end of said outer flap and pulling said outer flap away from said inner flap.