US3065897A - End closure for cartons - Google Patents

Description

Nov. 27, 1962 s. A. GRAPP END CLOSURE FOR CARTONS Filed April 4, 1955 INVENTOR.

ATTORNEY 3,065,897 END CLOSURE FOR CARTGNS Stanley A. Grapp, Minneapolis, Minn., assignor to General Mills, Inc., a corporation of Delaware Filed Apr. 4, 1955, Ser. No. 498,991 3 Claims. (Cl. 229--51) The present invention relates to improvements in closures for the ends of cartons and more specifically to an improved closure having a tear strip which may be torn from the carton end to gain access to the contents.

Cartons formed of paperboard such as white coated paper newsboard, chip board, and similar materials are well known to the art and are popularly used for merchandising many types of commodities. Cartons made of these materials are desirable in that they are inexpensive and yet have considerable strength to protect the contents and are well suited for handling with automatic machinery during the forming, filling, and closing processes. Cartons which are securely closed to protect the contents and to avoid accidental opening are, however, often diflicult to open.

There is, of course, a considerable merchandising advantage in providing a carton of the type used for household commodities which may be easily opened by the housewife without difficulty and without the aid of a knife or other opening instrument. Using an instrument to open a carton, in addition to causing inconvenience and being dangerous to handle, often damages the contents or the inner liners of the carton.

Attempts to provide cartons which are easily opened frequently counteract the effort to provide secure and complete protection for the contents since the opening feature frequently weakens the carton structure. Cartons weakened by opening devices can become damaged during the many times they must be handled from the time they are constructed, filled, and closed until the time they are received by the housewife in her kitchen. Efforts to provide easy-opening cartons have resulted in either a weakened carton and inadequate protection for the contents or in a more expensive carton which uses more material, is more costly, and is more difiicult to handle by the presently used automatic packaging machinery.

It is accordingly a primary object of the present invention to provide an improved carton structure which can be readily and easily opened but yet which provides the same protection to the contents as a carton which has no special opening feature.

Another object of the invention is to provide an improved carton with an easy opening feature that does not in any way restrict the handling of the carton by auto matic packaging machinery and in which the carton is not damaged by the machinery during handling.

Another object is toprovide a carton which has an easy opening feature that is not susceptible of being accidentally opened during handling and transporting.

A further object of the invention is to provide an improved tear strip type of opening for a carton which enables the carton to be easily and readily opened and yet which does not add to the cost of the carton material or to the cost of manufacturing the carton.

Other objects and advantages will become more apparent in the following specification and claims taken in ice 2 connection with the accompanying drawings which describe and illustrate certain preferred embodiments of the invention.

FIG. 1 is a plan view of the blank used for forming a carton;

FIGS. 2 and 3 are perspective views of the carton blank folded to complete the carton with the top end flaps in the process of being folded;

FIG. 4 is a perspective view similar to FIG. 2 but with the top end flaps being folded to close the carton;

PEG. 5 is a perspective view of the carton of FIGS. 2 to 4 illustrating the manner in which the carton is open by pulling the tear strip from the top;

FIG. 6 is a perspective view of the opened carton after the tear strip has been removed; and

FIG. 7 is an enlarged detailed view of a portion of one of the carton end flaps illustrating the detail of the preferred form of slits provided to form a tear path for the tear strip.

As recited in the above objects, the carton which illustrates the preferred embodiment of the invention is of the conventional type in many respects so that it may be used on a standard carton machine. This obtains an improved easy opening carton without necessitating the provision of special constructing, filling, and closing machinery.

The improvements exist largely in providing a top closure structure of a unique design which incorporates a tear strip having strategically positioned tear perforations and having critically arranged glue areas.

The blank for forming the carton is illustrated generally at 8 in FIG. 1 and is formed out of paper board material such as chip board or white patent coated newsboard or other materials well known to the packaging art.

It has been found that for purposes of the presentinvention a thickness of material from .016 to .022 of an inch is most desirable. This material is generally referred to in the packaging trade by point number such as 16 point or 22 point material. Material of this weight has suitable rigidity for protecting the contents and handling in high speed packaging machinery and yet is sufficiently thin and lightweight so as to provide a reasonably priced container.

1 The blank of FIG. 1 may be constructed by being cut from a roll of material or fiat stock by a die to the shape shown. The blank is shown with the surface which later becomes the outside of the carton facing upwardly. The indicia illustrated at 10 represents the identifying trademark of the product and appears on the front or longitudinal panel 12 of the carton.

Attached to the side of the front panel along a score line 14 is an intermediate or transverse side panel 16. Attached to this intermediate panel along score line 18 is a rear longitudinal panel 20. Attached to the opposite side of the rear panel along a score line 22 is another intermediate or transverse side panel 24, and the preceding panels will be folded along their interconnecting score lines to form a tubular shaped container as is illustrated in FIG. 2.

To secure the container in its tubular shape, a glued flap 26 is connected to the side of the front panel 12 along a score line 28 and this glued flap is suitably adhered to the inner surface of the intermediate side panel 24. The glued flap 26 will be inside the intermediate side panel 24 and on the inside of the carton as it appears in its position in the finished carton as shown in P16. 2.

As also illustrated in FIG. 2, the bottom end of the carton has been closed by folding the bottom end closure flaps across the tubular end of the carton. The position of these flaps on the blank is illustrated in FIG. 1 with flaps 30 and 32 being connected to the lower edges of the front and rear panels 12 and 20, respectively. Additional end closing tabs 34 and 36 are connected to the lower edge of the intermediate side panels 16 and '24, respectively, and these tabs are also folded across the lower end of the carton, usually beneath the end flaps 30 and 32. The flaps will be held in this folded position by a suitable adhesive placed between the surfaces of the tabs and end flaps.

With the carton thus formed, the top end, which is illustrated as having the improved opening feature, is then closed. The members which close the top end of the carton include first and second end tabs 38 and 40, with these end tabs being hingedly connected to the top edges of the intermediate side panels 24 and 16, respectively, along score lines 42 and 44. In addition to these end tabs, first and second end closing flaps 46 and 48 are provided. The first end flap 46 is hingedly connected to the rear carton panel along the score line 50. The second end closing flap 48 is hingedly connected to the front carton panel 12 along the score line 52.

In forming the carton blank, shown generally at 8 in FIG. 1, a die cuts the material to the shape shown and severs the lines to form the separate end tabs and flaps and is generally accompanied by a scoring machine of some type which forms the score lines interconnecting the panels, tabs, and flaps. These score lines are provided to define the lines of folding so that the carton may be more easily and more rapidly formed in the carton erecting machine. With the blank positioned face up as it is in FIG. 1, it is a simple operation during forming to add the additional step of applying a glue resistant material such as a varnish to select areas on the upper side of the blank. The present carton and glue resistant areas are arranged so that the resistant areas may all be applied from one side of the blank to serve the purposes which will later be described. Thus with very simple machinery used in the printing operation such as a rotating roll the glue resistant varnish is applied. The finish is illustrated in r the shaded areas 56, 58 and 60 which appear on the second tab 40, first end flap 46, and first end tab 38 with the areas being specifically located and having a specific configuration which will be later described in complete detail.

In addition to the operations of cutting, scoring, and varnish-applying, the blank is provided with slits which have a certain configuration and location to provide a tear path for the tear strip. These slits, which are arranged in rows to define the tear paths for the tear strip, are shown generally at 62 on the second top closure flap 48 and at 64 on the first top closure flap 46 in FIG. 1. These slits may be readily formed in manufacturing the blank by a rotating cutting wheel or a cutting knife which has cutting blades or a notched cutting surface positioned to form slits as shown in the drawings.

Turning now to the closing of the carton, which is constructed as previously described, in FIG. 2 the first and second end tabs 38 and 40 are shown folded across the end of the carton. This operation and the completion of the folding by folding the end flaps to overlie the end tabs, may be done manually or, as will be done in high speed production, by an automatic closing machine. Since the majority of the closing machines are designed for cartons of conventional shape and size, it is. an important feature that the present carton duplicates this conventional size and shape in most respects and that the easy opening tear strip is provided without a major change in the over-all configuration of the closure flaps so that the conventional closing machinery may be used.

It is also important, as will later become more clear, that the closing flaps retain their rugged structure since most of the closing machinery operates at very high speed and will tear or break a carton which has been weakened to provide an opening feature. With the present closure arrangement, the carton flaps are not weakened and will not be broken or damaged in being handled by high speed machinery.

After the end closing tabs 38 and are folded over the top of the carton, an adhesive is applied to the inner surfaces, or those which will face downwardly, of first end flap 46 and second end flap 48. The first end flap 45 is then closed as in 1 16.3. It will be noted that the width across the narrow dimension of the carton of the first folding flap is less than the width of the carton so that the flap does not cover the entire carton top and the free edge 66 will not extend to the other side of the carton when the ilap is in folded position as shown in HG. This edge 66 of the first flap will coincide with the slits 62 which define the tear path in the second fiap 43.

The second flap 48 is then folded down over the first 46 to complete the sealed carton which appears in its closed form in FIG. 4. As shown in FlG. 4 the second top closing flap 48 extends the full width of the carton so that it overlies the entire carton top with the exception of a portion 68 which is notched out to obtain access to the pull tab 70.

The pull tab 70 is located at one end of the tear strip 72 which is shown being removed in FIG. 5. The tear strip extends across the top of the carton and includes a part of the first closing flap and also a part of the second closing flap 48 with the edges of the strip being defined by the tear paths which follow the lines of slits 62 and 64.

The first line of slits 64 extends from the inner edge of the tear strip formed by the notch 74- in the first flap 46, across the first flap parallel to the carton edge which is the line of attachment 50 of the flap to the back panel 20 of the carton. The other tear path as defined by the line of slits 62 extends, as shown in FIG. 4, across the upper flap 43 from the outer edge 76 of the pull tab 70, parallel to the edge of the carton which is the line of attachment 52 of the second flap to the front carton panel 12.

Thus when the pull tab 70 is grasped and lifted from the carton, the tear strip will be torn from the carton top following the tear paths 62 and 64 in the manner shown in FIG. 5.

Since the second carton flap 48 extends completely across the narrow width of the carton, its outer edge 78, as shown in FIG. 5, will be lifted off the top surface 53 of the first flap. While it will be recognized that this upper flap could be shortened to coincide with the tear path 6 of the first flap, the additional width gained from the extension 78 creates a flat broad top for the carton which makes a better surface for purposes of stacking the carton and creates a better appearing carton. Further, this extension strengthens the first flap especially along the line of the slits 64.

t will be noted from FIG. 5 that in addition to the carton tearing along the tear paths as defined by the lines of slits 62 and 64, a number of fiat surfaces are separated from each other. First, the pull tab 70 must be separated from the first flap 38. Secondly, the edge extension '78 of the second flap separates from the upper surface 58 of the first flap, and the rear end of the tear strip d2 will have to separate from the second tab 4t). To facilitate this easy separation, the surfaces may not be adhered to each other but this requires the application of adhesive only over a certain pattern which is difficult and means that these areas are free to separate during handling and shipping. In the present embodiment of the invention, the surfaces are adhered to each other in a controlled manner. One method of obtaining this controlled adherence would be to arrange the glue pattern which is applied to the carton surfaces in such a manner that glue would be placed on these areas in a specified pattern which would permit easy separation of the areas yet prevent their accidental separation. Since the present package is expressly designed to be used with existing packaging machinery, it has been found that it is expedient to place a glue resistant varnish on the separable areas in a specific pattern. This prevents the glue from soaking into the material andforming a bond between the flaps. It has been discovered, however, that if the surfaces which are to be separated when the tear strip is removed are in no way adhered to each other, the strength of the carton is impaired and pressure applied to the sides and back of the carton, for example, may cause the closure flaps to bow upwardly and separate. This is especially true since some resilience remains in the flaps when they are folded. Also, shifting, jarring, or pressing of the carton may cause the surfaces to separate to a degree where the tear strip may be accidentally torn from the package, thus opening the carton before it is desirable to do so. Therefore select areas are not coated with the adhesive-resistant varnish so that the adhesive will penetrate the material at these critical areas.

The glue resistant varnish is shown generally at the areas 56, 58 and 60 in FIG. 1. In the area 60, as shown in FIGS. 1 and 2, which lies beneath the pulltab 70, a centrally located circular area 84 is left free from adhesive resistant material and thus the adhesive which penetrates that spot will tend to hold the pull tab against the fiap 38. This area may be supplemented by auxiliary varnish-free areas 86 which also will be susceptible to glue and will strengthen the union between the pull flap 70 and the tab 38.

The varnish-free areas, however, are sufiiciently small so that the pull tab can be readily grasped and the glue in said free areas broken to lift the'tab from the package. At the other end of the tear strip, the first flap 46 is adhered to the second tab 40. The center of the area of the tear strip is however coated with adhesive resistant material 56 which has a rectangular pattern. The rectangular pattern is shorter than the length of the second tab 40, however, so that short spaces 38 and 91} remain at its edges to hold the tear strip down against the tab. This small holding area is sufficient to prevent the surfaces from becoming accidentally separated but is not strong enough to prevent the tear strip from being torn from the carton. With the end and especially the center portion of the end of the tear strip being adhered to the tab beneath it, the

center of the carton top will not how up due to separation of the surfaces when pressure is applied to the front and back of the carton.

Another area which is covered with the adhesive resistant material and subject to the controlled adhesion is shown at 58 on the first flap. This area underlies the extension 78 of FIG. 5 of the second flap. To prevent this outer edge 78 of the second flap from becoming accidentally separated from the first flap, a series of small circular areas 92 are left uncoated by the strip 58 of adhesive resistant material. The adhesive then penetrates the material in the small areas and causes the edge of the second flap, as shown at 78 in FIG. 5, to be adhered to the first flap but the adherence is such that the two surfaces can be separated when the tear strip is lifted.

The area 58 of adhesive resistant material serves a second important purpose in that it coats the slits 64 and adjacent areas which form the tear path at one side of the tear strip. This coating prevents the adhesive from soaking into the slits which would tend to render the slits ineffective since the glue would adhere the slits and adjacent areas to the opposite flap 48 and also prevent the slits from separating. The row of slits.62 may also be coated with adhesive resistant material but is not shown as being so coated in the drawings since when the second flap 48 is placed over the first flap 46 in the step illustrated in FIG. 3, the edge 66 of the first flap lies short of the line of slits 62. The slits 62 or adjacent areas will not contact flap 46 and the adhesive will not be forced up into the slits. Further, to coat the row of slits 62 on the under surface of the second flap 48 would require an additional step in the preparation of the blank of FIG. 1 since this coating would have to be on the rear surface of the blank rather than on the top surface as is possible with the coated area 58.

The open package is shown in FIG. 6 with the tear strip removed. This obtains access to the interior of the carton. The narrow areas 96 and 98 which are the remaining parts of the first and second closure flaps may be folded back as may the end tabs 38 and 40 to completely open the top of the carton.

An important feature of the carton structure is the arrangement of the slits which define the tear path on each side of the tear strip. These slits are shown enlarged in FIG. 7 which illustrates a portion of the first flap 46. The row of slits 64 which defines the tear path is comprised of a series of angular slits which extend at an angle to the general direction of the tear path. Each succeeding slit slants in a direction opposite to the preceding one. For example, slit 100 slants in one direction with respect to the general tear path and slit slants in the opposite direction.

It has been found that there is an optimum angle for the slits to obtain the best performance with the weight of material previously referred to. That is, with a material having a weight between 16 point board and 22 point board (.016 to .022 of an inch thick) an angle of 45 obtains the best performance and an angle between 30 and 60 must be maintained or the advantages of the invention will reduce or disappear. Thi slit angle is illustrated at 104 and is the general angle between the slit and the tear path or the direction of tear.

The length of the slit has also been found to be critical for the weight of material with an optimum length being ,4; inch. The length of the slit should be within the range of -i to of an inch to obtain the benefits of the structure illustrated. The distance between the ends of the slits is also important and this distance as shown at 108 should be between and of an inch.

An important feature of the invention is the position of the slits with respect to the edge of the pull tab 70. It will be noted from FIG. 7 that the inner edge of the pull tab, which is the base of the notch 74, leads to the inner end of the first slit 110. That is, the inner end of the slit 110 is aligned with the edge of the pull tab 70 and the slit angles outwardly from the pull tab. The succeeding slits are each aligned with the first slit 110 and thus the inner ends of each of the slits form a straight line aligned with the edge of the pull tab.

This arrangement is followed at the other edge of the tear strip and as is illustrated in FIG. 4, the first slit 112 has its inner end aligned with the outer edge 76 of the pull tab 70 and leads away from the tear strip. Each of the succeeding slits of this line of slits 62 is also aligned with the first slit 112 so that the inner ends of each of the slits align themselves with the outer edge 76 of the pull tab 70 which corresponds to the outer edge 66 of the first flap 46 as shown in FIG. 2.

This arrangement of the slits insures that when the pull tab 70 is lifted, the first tearing action will be directed along slits 110 and 112 away from the center of the tear strip so that in the event that the tearing leaves the the tear paths 62 or 64, the tear will tend to go out toward the edge of the carton. If the tear strikes the edge of the carton, it will either follow down the fold line at the carton edge or wander back to the edge of the tear strip but will not move into the tear strip area where it might meet the other tear path and break ofi the tear strip short of its entire length, thus preventing the carton from being opened. Another feature of this placement of the slits with their inner ends aligned with the outer edges of the pull tab obtainsthe widest tear strip possible without the tear path being completely at the edge of the carton top.

U Perforations along the edge of a carton top cause extreme weakening in the over-all strength of the carton.

An important advantage of the angular slits which form the tear path is that they do not weaken the closing flaps of the carton as is the case if the ordinary straight line per forations are used. The straight line perforations can cause the carton flaps to break along the tear line, especially when being folded by high speed machinery. With the structure shown, the flaps are not weakened since the slitting is spread out over a broad area and the closure flaps retain their original shape and strength throughout their closing and handling life until the time the carton is opened by the housewife.

The slits, however, present a tear line which is sufficiently weakened and susceptible to stresses of the type caused by pulling on the pull tab so that the carton may be easily and readily opened by hand, as is shown in PEG. 5. Further, the zigzag slits cause a positive and certain separation of the material along the tear path and tend to prevent separation of the layers of the material with the unsatisfactory result of the separation of the tear strip and incomplete opening.

It will thus be seen that the present carton closure structure presents a carton end closure structure which enables a carton to be easily and readily opened for access to the contents. The easy opening feature, however, does not reduce the effectiveness or the strength of the carton, and it is important that this feature does not prevent the carton from being handled by existing automatic packaging machinery. The specific arrangement of the adhesive resistant areas both strengthens the carton and yet makes the tear strip easily removable. The arrangement and position of the slits which form the tear path does not retract from. the strength of the closing flaps and yet enhances the removability of the tear strip to obtain an improved carton.

I have, in the drawings and specification, presented a detailed disclosure of the preferred embodiment of my invention. It is to be understood that the invention is susceptible of modifications, structural changes and various applications of use within the spirit and scope of the invention and I do not intend to limit the invention to the specific form disclosed but intend to cover all modifications, changes and alternative constructions and methods falling within the scope of the principles taught by my invention.

I claim as my invention:

'1. A carton comprising a tubular body rectangular in cross section formed of longitudinal and transverse panels with end fiaps folded across an end of the carton body to form an end closure, the end flaps including at least one inner tab hinged to a transverse panel of the carton, a first outer flap hinged to one longitudinal panel and overlying at least part of said inner tab, a second outer flap hinged to the opposite longitudinal panel and at least partially overlying the first outer flap, said first outer flap extending from its hinge less than the full width across the body end and thereby having a free edge spaced inwardly from the hinge of the second fiap, said outer flaps providing a tear strip which includes overlying areas of the outer flaps, and extends fully across the fiaps and cart-on end with one end of said tear strip overlying said inner tab, said tear strip being defined at one side by a first weakened tear line in the first outer flap parallel to and spaced between the hinge connection and free edge of said first outer flap and extending substantially across the flap and carton end, and said tear strip being defined at its opposite side by a weakened tear line in the second outer flap in substantial alignment above the underlying free edge of the first flap, means providing adhesive engagement between said outer flaps and joining them to each other within the area of the tear strip, and means providing limited adhesive attachment between the said inner tab and at least one of the outer flaps, said last mentioned means providing a. limited 5:3 readily releasable adhesive bond between said inner tab and. the overlying tear strip end for ready outward removal of said tear strip end and separation of said tear strip atong said weakened lines and free edge, while bonding said tear strip end against premature accidental removal from said inner tab.

2. A carton comprising a tubular body rectangular in cross section formed of longitudinal and transverse panels with end flaps folded across an end of the carton body to form an end closure, the end flaps including a pair of opp-ing inner tabs hinged to opposite transverse panels of the carton, a first outer flap hinged to one longitudinal panel and overlying at least part of each inner tab, a second outer flap hinged to the opposite longitudinal panel and at least partially overlying the first outer fiap, said outer flaps providing a tear strip area which includes overlying portions of the outer flaps, said tear strip having at one side a first single weakened tear line in only the first outer fiap and having at its other side a second single weakened tear line in only the second outer flap, each of said tear lines being parallel to and paced between the hinge connection of its flap and the other of said tear lines and extending substantially across the flap and carton end with said tear strip having ends overlying each of said inner tabs, each of said weakened lines comprising spaced slits inclined at an angle to the weakened line itself, said first outer flap extending only partially across the carton end toward the hinge connection of the second outer flap, said first outer flap thereby having a free edge in alignment with the single weakened tear line of the second outer flap to define one edge of the tear strip, the second outer flap extending substantially fully across the carton with its outer edge close to the hinge connection of the first outer flap, means providing adhesive engagement between said outer flaps and joining them to each other within the area of the tear strip, saidmeans providing adhesive engagement between the outer flaps including means defining a substantial region between the tear strip area and the outer edge of said second outer flap in which the outer flaps are adhered with a limited readily releasable adhesive bond for ready removal of the outer edge of said second outer flap with said tear strip, and means providing limited adhesive attachement between said inner tabs and at least one of the outer flaps, said last mentioned means providing adhesive attachment between said inner tabs and outer flap in a substantial area outside the tear strip and also providing a limited readily releasable adhesive bond between said inner tabs and overlying tear strip ends for ready removal of said tear strip ends, while bonding said tear strip ends against premature removal from said inner tabs.

3. A carton comprising a tubular body formed of side panels with end flaps folded across an end of the body to form an end closure, the end flaps including a first closure flap hinged to one panel at a first hinge line, and a second closure fiap hinged to an opposite panel at a second hinge line and at least partially overlying the first flap, said first and second closure flaps being adhered to each other and having a tear strip area which includes overlying portions of both said fl ps, said tear strip having at one side a first weakened line extending substantially entirely across the width of said first flap and spaced between said first and second hinge line, said tear strip having at its opposite side a second weakened line extending substantially entirely across said second flap and spaced between said second hinge line and said first weakened line, each of said weakened lines comprising spaced slits inclined at an angle to the weakened line itself, and said first closure flap having a free edge spaced between said first and second hinge lines and located in substantial alignment under said second weakened line with said inclined slits of the second weakened line having one end in alignment above said free edge and the other end extending from said free edge said first weakened line and along said opposite side 5 of the tear strip by tearing said second weakened line, as said tear strip end and free edge of the first flap are pulled upwardly.

References Cited in the file of this patent UNITED STATES PATENTS 10 Trost Apr. 14, 1931 Lowey July 5, 1938 Lenz Sept. 24, 1940 Hothersall Aug. 18, 1942 Guyer June 20, 1944 Gilbert Oct. 17, 1944 Mullinix May 25, 1954 FOREIGN PATENTS Great Britain July 8, 1936 Great Britain June 17, 1948

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