US3003677A - Tightly sealed cartons - Google Patents

Description

Oct. 10, 1961 R. J. HENNESSEY 3,003,677

TIGHTLY SEALED CARTONS Filed July 11, 1958 &

INVENTOR Russell J fiennessey 3W (LEM I! I Z 1 76. 5 27 25' 2 ATTORNEY United States Patent 3,003,677 TIGHTLY SEALED CARTONS Russell J. Hennessey, St. Paul, Minn., assignor to Waldorf Paper Products Company, Ramsey County, Minm, a corporation of Minnesota Filed July 11, 1958, Ser. No. 748,048

- 1 Claim. (Cl. 229-37 This invention relates to an improvement in tightly sealed cartons and deals particularly'with a tubular carton having tightly sealed ends.

One of the major difiiculties in the production of a tubular carton lies in the difiiculty of producing a tightly sealed end closure on the carton. One end of such a carton may often be sealed over a mandrille and may be tightly sealed because of the external pressure which may be applied against the flaps, However, in sealing the last end of the carton, the closing flaps have a tendency to fold inwardly producing an imperfect seal.

' Tightly sealed cartons have recently become even more important since they have been used to package frozen food and the like. It is normally thought necessary to place the food product in a paper board carton and to overwrap the carton with a film of cellophane or the like to provide a more effective seal. The overwrapping of the cartons requires a separate step or operation which increases the cost of packaging. Furthermore, in spite of the fact that overwrapping machines have been greatly improved over the years, they are complicated machines and are somewhat more erratic in their operation than the various other machines in the packaging'line.

An object of the present invention resides in the provision of a tightly sealed carton which can be somewhat more effectively sealed than cartons of common construction. The leakage through the end of a sealed end carton usually takes place between the various laminations of paper board which form the end closure. As the closing flaps are sealed, channels may be formed between the various flaps due to the thickness of the paper board which often form a communication to the interior of the carton, thus destroying the effectiveness of the seal.

Tubular cartons are normally made with two of the side wall panels somewhat wider than the remaining two panels and with the closing flaps cut to a length approximately equal to the width of the narrower panels. As a result, when the closing flaps are closed, the flaps on the two narrower panels are normally first folded down into a common plane and the flaps on the wider panels are folded down into surface contact overlying the first folded panels. When glue is applied to the first folded flaps, an outward pressure is exerted against the closure, there is a tendency for the flaps on the narrower panels to fold down into the carton and to not seal effectively to the flaps of the wider panels. This tendency is increased by the tendency of the paper board to curl when moistened by the adhesive. Accordingly, it is a feature of the present invention to change the normal sequence of folding the flaps and to fold one of the closing flaps on a wider panel into right angular relation with its side wall, to then fold the two flaps on the narrower panels to overlie the first folded flap, and then to fold the opposite flap on the remaining wider panel to overlie the flaps on the narrower panel. In the past, this sequence of folds has not been used insofar as the applicant is aware because of the fact that the flaps on the narrower panels normally terminate in spaced relation providing a channel between the ends of these flaps through which the product may sift. Accordingly in the present invention, a part of the flaps on the narrower panels is cut away and a corresponding part of the outermost flap is embossed out of its normal plane so as to effectively seal 3,003,677 Patented Oct. 10, 1961 again the first folded flap. An effective seal has been produced in this manner.

A feature of the present invention resides in the provision of a tublar carton having closing flaps which are sealed in the sequence described and in which the last sealed flap is provided with a section which is embossed out of the plane of this flap an amount substantially equal to the thickness of the paper board. This embossed area is designed to seal against the first folded flap to compensate for the thickness of the intermediate flaps.

- In the past it has been proposed to provide a score line in the last folded flap defining a particular area to be sealed against the first folded flap, the thought being that this score line would permit a defined area of the last sealed flap to fold into surface contact with the first folded flap. In actual practice, this arrangement has not functioned effectively due to the fact that the makeready used in the formation of the score line produces a projecting rib on the last closed flap which tends to hold the adjoining portions of this flap out of surface contact with the first folded flap, thus destroying the effectiveness of the seal.

These and other objects and novel features of the present invention will be more clearly and fully set forth in the following specification and claim.

In the drawings forming a part of the specification,

FIGURE 1 is a perspective view of a frozen food carton showing the general arrangement thereof.

FIGURE 2 is a cross-sectional view through the manufacturers joint of the carton illustrated in FIGURE 1.

FIGURE 3 is a perspective view of an end of the carton after three of the closing flaps have been folded into closed position.

FIGURE 4 is a sectional view through the sealed end of the carton after the sealing has been completed, the position of the section being indicated by the line 44 of FIGURE 1.

FIGURE 5 is a diagrammatic view of the blank from which the carton is formed.

The particular carton which is illustrated in the drawings is of proper size and proportions to contain a frozen pie or the like. Obviously the proportions of the package may be changed depending upon the use to which the package is to be put.

As illustrated in FIGURE 5 of the drawings, the package includes a front wall 10 which is foldably connected along a fold line 11 to a bottom panel 12. The bottom panel 12 is connected along a fold line 13 to a rear wall 14. The rear wall 14 is connected along a fold line 15 to the top panel 16. The top panel 16 is foldably connected along the fold line 17 to the glue flap 19. The glue flap 19 is provided with a fold line 20 which extends parallel to the fold lines 17 and divides the glue flap into an upper portion 21 which is adhered in surface contact with a portion of the front wall 10 and a projecting flap 22 which is shown as being free of adhesive contact with the front wall 10 to provide a flange which may be grasped by the fingers and pulled upwardly to open the carton.

End closure flaps are connected to the various panels along parallel lines of fold 23 and 24. The closing flaps 25 which are connected to the bottom panel 12 are of proper dimensions to close the entire end area of the tubular carton. Corner flaps 26 are connected to opposite ends of the front wall 10 and similar corner flaps 27 are foldably connected to the rear wall panel 14. Closing flaps 29 which are hingedly connected to the top panel 16 are of substantially the same dimensions as the flaps 25.

As indicated in the drawings, the flaps 26 and 27 are provided with arcuate notches 30 and 31 respectively which extend from a point closely adjacent to the fold 3 lines 23 and 24 to the ends of these flaps. The notches 30 and 31 are positioned to expose portions of the closing flaps 25 in the area of their connection with top panel 16. It will be seen that when the end flaps 2,5 are folded upwardly from the bottom panel 12 and the 20 1? fl ps. 30 and 31 are folded into surface contact with the flap 25, an area of the closing flapsv 25 is exposed between the ends of the flaps 30 and 31 and also throughout the length of the portions of the fold lines 23 and 24 which hingedly-connect the closing flaps 29 to the top panel 16. This provides an open area on the flaps 29 to which the outer flaps 25 can be adhered, the area being closely adjacent the hinge connection between the flaps 29 and the top panel 16' where these flaps are most resistant to inward pressure.

As is indicated in FIGURE of the drawings, the

flaps 25 are provided with embossed edge areas 33 which are embossed into ofiset relation from the plane of the remainder of the flaps 25 along the lines 34. The lines 34 extend generally parallel to the edges of the flaps 25 throughout most of the length and the ends of the lines 34' are curved to fit the contour of the notches 30 and 31 of the corner flaps 26 and 27. The embossed areas 33 are offset from the plane of the remainder of the panels a distance substantially equal to the thickness of the paper board. Accordingly, when the flaps, 25 are folded upwardly into surface contact with the flaps 29, the embossed area will lie in surface contact with the exposed.

' portion of the flaps 29 and may be adhered securely thereto.

By providing the embossed areas 34, which are obviously embossed in a manner to offset the embossed areas toward the flaps 29 when the carton is closed, much tighter seal is effected than would otherwise be possible. Without such an embossed area, channels or passages are formed between the flaps 29 and 25 due to the thickness of the intermediate flaps 26 and 27. These passages are eliminated by the arrangement disclosed.

In accordance with the patent statutes I have described the principles of construction and operation of my tightly sealed carton, and while I have endeavored to set forth the best embodiments thereof, I desire to have it understood that obvious changes may be madewithin the scope of the following claim without departing from the spirit of my invention.

I claim:

A paper board carton including four side and end panels hingedly connected in tubular relation, a first end closure flap on one of said side panels having an area substantially equal to the area of the end of said carton and adapted to provide. an inner closing flap, a pair of end closure flaps hinged to said end walls and adapted to. fold outwardly of said' first end closure flap in face contact therewith, said pair of end closure flaps being notched by cutting away portions of the edges thereof overlying the fold line connecting the first end closure flap to said one side panel to expose .an area of this first end closure flap adjoining the last mentioned fold line, and an end closure flap on the remaining side wall having an area substantially equal to the end area of the carton, and an embossed area on the end edge thereof oflset toward the first end closure flap when the flaps are in closing position, said embossed area being shaped to conform with the cut edges of said notches and to extend between said notches, and to lie in face contact with said first end closure flap in said area.

References Cited in the file of this patent UNITED STATES PATENTS 1,869,751 Iacobitti Aug. 2, 1932 2,403,047 Buttery July 2, 1946 2,546,099 Dunning Aug. l4, 1951 2,661,141 Zinn Dec; 1, 1953

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