US3491937A - Easily openable carton - Google Patents

Description

7, 1970 w. A. BRASTAD 3,491,931

EASILY OPENABLE CARTON Filed May 17, 1968 INVENTOR. WILLIAM A. 525m) ATTORNEY United States Patent 3,491,937 EASILY OPENABLE CARTON William A. Brastad, Minneapolis, Minn., assignor to General Mills, Inc., a corporation of Delaware Filed May 17, 1968, Ser. No. 730,063 Int. 'Cl. B65d 17/00, /54, 5/70 US. Cl. 229-51 1 Claim ABSTRACT OF THE DISCLOSURE The present invention relates to improvements in carton closures. More particularly, it pertains to an improved closure formed of two flaps having an arrangement of adhered spots and partial cuts which permit easy separation of such flaps and control the delamination thereof when the outermost of such flaps is pulled outwardly and away from said carton closure.

Cartons formed of paperboard such as bleached kraft, white coated paper newsboard, chipboard and similar materials are well known to the art and are widely used. Cartons made of these materials which are securely closed to protect their contents and to avoid premature accidental opening are sometimes diflicult to open without the aid of a knife or other opening instrument. One common structure which is used to open such cartons is a closure formed of two overlapping flaps releasably adhesively held together, with the outermost of said flaps having an opening tab portion attached thereto and projecting therefrom which when pulled upwardly and away from the closure causes said flaps to separate. When said flaps separate they are folded back and access to the carton contents is gained. It has been found when using this common structore that at times the flaps are so securely held together by the adhesive that pulling the opening tab member upwardly and away from the closure causes one or the other of said overlapping flaps to delaminate over large areas rather than separate neatly from each other.

Accordingly, it is one object of the present invention to provide an opening structure which for a given amount of adhesion between two end closure flaps decreases the possibility of large area delamination of either of the flaps of the closure as they are pulled apart.

Another object is to provide a closure formed of two adhesively held together overlapping flaps with a pull tab portion projecting from a free edge of the outermost of said flaps with inexpensive means so when said tab is lifted upwardly and away from said closure the stresses created are more evenly distributed and there is less likelihood of said tab tearing off and/or said outermost flap tearing before said flaps are separated.

Other objects and advantages of the present invention will be apparent from the following description in which certain preferred embodiments of the invention are disclosed.

In the drawings which form a part of this application,

FIGURE 1 is a plane view of a carton blank for form ing one embodiment of the present invention;

FIG. 2 is a perspective view of a carton end closure formed from the carton blank of FIG. 1 with some of the closure flaps being folded to close the carton end;

FIG. 3 is a perspective view similar to FIG. 2 with another of the closure flaps being folded to close the carton end;

3,491,937 Patented Jan. 27, 1970 "ice FIG. 4 is a perspective view of the carton of FIGS. 2 and 3 with all of the closure flaps folded to close the carton end;

FIG. 5 is a perspective view of the carton of FIGS. 2-4 illustrating the manner in which the carton is opened by pulling the opening pull tab portion of the outermost closure flap upwardly and away from the end closure;

FIG. 6 is a perspective view of the carton of FIGS. .2-5 with the outermost flap having been pulled away from the end closure shown in FIG. 4; and

FIG. 7 is a perspective view of the carton embodying the present invention which has been reclosed by tucking the pull tab of the opening tab portion of the outermost .flap into a slit formed in the other flap of the end closure.

In FIGURE 1 a blank 10 is illustrated for forming the carton end closure of the present invention. The blank 10 for forming the carton 12 (illustrated in FIG. 2) is formed out of paperboard material such as bleached kraft, white coated paper newsboard, chipboard or other materials well known to the carton art.

The blank 10 is shown with the surface which later becomes the outside of the carton 12 being uppermost. The blank 10 comprises a glue panel 14, a front side panel 16, a first end side panel 1 8, a rear side panel 20, and a second end side panel 22. These side panels are hingedly connected at score lines 24, 26, 28, and 30, as shown in FIG. 1. Hingedly attached to the lower portions of the side panels 16, 18, 20, and 22, are bottom end flaps 32, 34, 36 and 38, respectively. Said bottom flap attachment is along a score line 40. Hingedly attached to the upper portions of the side panels 16, 1-8, 20, and 22, are top end closure flaps 42, 44, 46, and 48, respectively. The flaps 44 and 48 are sometimes hereinafter referred to as tabs. Said top flap attachment is along a score line 50.

The top end flap 46 has a tab 52 extending therefrom while the top end flap 42 has a free edge 53 and an inverted C-type slit 54 therein. The tab 52 and the slit 54 are designed and positioned so that when the carton 12 (see FIG. 2) has been opened once and it is desired to reclose said carton, the tab 52 can be inserted into the slit 54 as shown in FIG. 7.

The closure flap 46 has a closure flap portion 46a and an opening portion 46b which includes the pull tab 52. The portions 46a and 46b are contiguous along a predetermined line 56. The line 56 has means associated therewith to facilitate the upward bending of the opening portion 4612 including the tab 52 relative to the closure flap portion 46a. along said line when a force is exerted on said tap upwardly and away from the end closure of the carton as is illustrated by arrow A in FIG. 5. In the preferred embodiment this means is a score line coincident with the line 56. The score line extends completely across the base of the opening portion from one end of the closure flap 46 to the other end of the closure flap 46.

To secure the carton body in its tubular shape as is illustrated in FIG. 2, the glue panel 14 is adhesively bonded to the inner surface of the second side end panel 22, i.e., the surface of said panel 22 which cannot be seen in FIG. 1.

The closure flaps or tabs 44 and 48 which are hingedly attached to the end side panels 18 and 22, respectively, are provided with a glue resistant material such as varnish at selected areas 58 and 60, respectively, on the upper surfaces. In the area 58 a circular area or spot 62 is left free from adhesive resistant material and thus only the adhesive which penetrates spot 62 will tend to hold the flap 42 against the flap 44 when flap 42 is placed to overlie said flap 44. This spot 62 may be supplemented by auxiliary varnish free areas which also will be susceptible to glue and will strengthen the union between the flap 42 and the flap 44. Similarly, the area 60 has a circular area or spot 64 which is left free from adhesive resistant material and thus only the adhesive which penetrates the spot 64 will tend to hold the flap 42 against the flap 48 when flap 42 is placed to overlie said flap 48. The area 64 may also be supplemented by auxiliary varnish free areas which will be susceptible to glue and will strengthen the union between the flaps 42 and 48. Limiting the areas of adhesive attachment between flap 42 and flaps 44 and 48 as set forth provides a limited readily releasable adhesive bond between flap 42 and flaps 44 and 48 when an aqueous adhesive is applied to the spots 62 and 64. This limited readily releasable bond permits ready separation of said flaps when a force is exerted thereon, While at the same time bonding said flaps together against premature accidental separation.

As shown in FIG. 1, the top surface of flap 42 is provided with a glue resistant material such as varnish in the area 66. In this area 66, which lies beneath the closure flap portion 46a, the closure flap portion 46b, and the pull tab 52 of the flap 46, are located a number of distinct areas or spots 68 which are left free from adhesive resistant material and thus the adhesive which penetrates the distinct areas or spots 68 will tend to hold the closure flap 46 against the flap 42. These distinct areas 68 may be supplemented by auxiliary varnish free areas which will also be susceptible to glue and will strengthen the union between the closure flap 46 and the flap 42.

Extending from each side of each of the distinct areas or spots 68 to the free edge 53 of the flap 42 are partial cuts 70. These cuts 70 extend partially through the closure flap 42 from the upper surface thereof toward the bottom surface thereof, i.e., from the surface seen in FIG. 1 toward the surface of flap 42 which cannot be seen in FIG. 1. As shown in FIG. 1, the cuts 70 which extend from either side of one particular circular area 68 are angled to converge toward each other. In addition to the partial cuts 70, additional partial cuts 72 are also made in the upper surface of the closure flap 42. These cuts 72 extend across the distinct areas 68 and extend partially through flap 42 from the upper readily visible surface of the flap 42 toward the bottom surface of the flap 42. The cuts 70 and 72 can extend from to 75% through the closure flap 42, with the preferred range being from 40% to 60% through the closure flap 42. In any event, the cuts 70 and 72 should extend through the flap 42 at least as far as the adhesive used to bond the flaps 42 and 46 penetrates flap 42.

Limiting the areas of adhesive attachment between flaps 42 and 46 to the distinct areas 6 8 provides a limited adhesive bond between said flaps when an adhesive is applied to the areas 68. This type of bond together with the partial cuts 70 and 72 permits ready separation of the flaps 42 and 46 when a force is exerted on the pull tab 52 upwardly and away from the end closure as shown by arrow A in FIG. 5, while at the same time facilitating, controlling, and directing the delamination of the flap 42. This type of bond also holds said flaps together against premature accidental separation.

' To close the carton end, the end closure flaps 44 and 48 are folded across the end of the carton as illustrated in FIG. 2 and an adhesive is applied to the distinct areas or spots 62 and 64 of the uppermost surfaces of end flaps or tabs 44 and 48. The first closure flap 42 is then closed as in FIG. 3 and an adhesive is applied to the distinct areas 68. The adhesive applied can be either an aqueous adhesive or a hot melt adhesive just as long as the bond between the flaps 42 and 46 caused therebyis limited to the distinct areas 68 between the partial cuts 70. The distinct area can take shapes other than circles, for example, diamonds, rectangles and squares. In addition, the partial cuts 70 and 72 could be in the flap 46 to control delamination.

It will be noted that the width across the narrow dimension of the first closure flap 42 is less than the width of the carton end so that said flap does not cover the entire carton end when said flap is folded as shown in FIG. 3.

The second closure flap 46 is then folded down about hinge line 50 to partially overlie the first closurefiap 42 to complete the sealed carton which appears in its closed form in FIG. 4. As shown in FIG. 4, the second closure flap 46 extends less than the .width of the carton across the end closure and the pull tab 52-which is connected to closure flap 46 extends further across said end closure.

As shown in FIG. 5, the carton 12 is easily opened by grasping the tab 52 and bending said ta'b upwardly and away from the first flap 42. This causes the tab 52 to fold about hinge line 56, into the position shown in FIG. 5. Now, when additional force is applied to the tab 52 in the direction of the arrow A, the adhesive bond between closure flap 46 and flap 42 causes the flap 42 to delaminate. This delamination begins at the distinct areas 68 and is controlled to remain within the areas bounded by the partial cuts 70 and 72 and the free edge 53 of the flap 42. The partial cuts 70 and 72 facilitate and control this delamination of the flap 42 so that it extends from the distinct areas 68 to the free edge 53 of the flap 42. The delaminated parts of flap 42 are shown by the numerals 74 in FIG. 6. By grasping flap 42 and exerting an upward force thereon the adhesive bond between flap 42 and flaps 44 and 48 causes slight delamination in flaps 42, 44 and/or 48 if hot melt adhesive had been used in the distinct areas 62 and 64 and said flap 42 can be moved to the position shown in FIG. 2. However, the varnish free areas, 62 on flap 44, and 64 On flap 48 are sufficiently small so that the glue in said areas readily releases the flaps joined together thereby when a force is exerted to separate said flaps and extensive delamination does not occur. The bond created in these areas is thus a limited bond for ready separation of the flaps joined 1 thereby when a force is exerted on said flaps, while at the same time bonding said flaps together against premature accidental separation.

Reclosure of the open package shown in FIG. 2 without the use of adhesive bond is effected by moving the flap 42 back to the position shown in FIG. 3, then moving the flap 46 into the position shown in FIG. 6 and tucking the tab 52 into the slit 54.

In view of the principles set forth herein, I have shown some of the ways of carrying out the present invention and some of the equivalents which are suggested by these disclosures.

Now, therefore, I claim:

1. A carton end closure for a carton body comprising a first flap, a second flap at least partially overlying said first flap, said first flap having a free edge underlying said second flap,- means providing an adhesive bond between said first and second overlapping flaps in distinct areas of such flaps, and at least said first flap having partial cuts, each of said distinct areas having one of said partial cuts extending from one side toward the free edge of said first flap and having another one of said partial cuts extending from the opposite side toward the free edge of said first flap, said first flap having an additional partial cut extending between said partial cuts positioned on either side of each of said distinct areas, each such additional partial cut for each said distinct area being positioned further fromsaid first flap free edge than at least a portion of said distinct area.

7 References Cited UNITED STATES PATENTS Miller 22951

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