CARTON CLOSURE STRUCTURE

Abstract: An end closure structure for a tubular structure has lines of joinder with closure flaps that are disposed to minimize the deformable area of an end wall by creating a tight structure that is less prone to blousing or bulging. The length of top (22) and bottom (26) panels is less than the length of side panels (24). The side panels terminate in weakened lines of joinder (55) that are arced toward adjoining side flaps (25). Almond-shaped transition panels (60) further facilitate a snug, secure end closure that is not easily deformed by bulging or blousing.

Description: CARTON CLOSURE STRUCTURE The invention relates to cartons, and more particularly, to cartons having a closure structure that enhances carton integrity and appearance. It is important when forming enclosed packages of articles to have a package that is secure and not prone to unexpected opening and that does not present problems in handling. A problem with known end or side-loaded tubular type cartons is that the end structures become slack upon stacking and handling of the packages. This is particularly true when articles such as beverage cans are packaged in cartons. Modern beverage cans usually have top and bottom components that are smaller in diameter than the body of the can. This means that there is often substantial space between the corners of the end structure of a carton and the tops and bottoms of the cans, hi addition, the cans are typically designed to telescopically nest when they are stacked one upon another. Thus, when packages of cans are stacked upon one another the cans tend to nest as much as they are able. This action decreases the overall height of a carton thereby causing the end walls to bow outwardly. This outward bowing, or bulging, is also known as blousing. Blousing creates problems because it can place undue stress upon the flaps forming the end walls of cartons thereby causing glued panels to fail. A blousing type of carton deformation also creates a protrusion, which can cause snags or otherwise interfere with handling. The present invention and its preferred embodiments seek to overcome or at least mitigate the problems of the prior art. One aspect of the invention provides a carton comprising opposing top and bottom panels and opposing side panels adjoining one another forming a tubular structure, side flaps foldably adjoining said side panels along respective first weakened lines of joinder each arcing toward said side flaps, major flaps foldably adjoining said top panel along respective second weakened lines of joinder, and minor flaps adjoining said bottom panel along respective third weakened lines of joinder, and wherein a length of at least one of said top and bottom panels is less than a distance between apexes of arcs of said side panels. Preferably, the lengths of both said top panel and said bottom panel are lengthwise less than said distance between apexes of arcs of said side panels. According to an optional feature of this aspect of the invention the top panel and the bottom panel may be of substantially equal length. According to another optional feature of this aspect of the invention there may further comprise inwardly-inclined transition panels at respective ends of the side panels each formed by a pair of first weakened line of joinder and a fourth weakened line of joinder arcing toward a distal end of the side panel. A second aspect of the invention provides a carton for accommodating a plurality of articles comprising opposing top and bottom panels and opposing side panels adjoining one another forming a tubular structure, a pair of opposed side flaps hingedly connected to each of said side panels along opposed first fold lines, major flaps hingedly connected to said top panel along respective second fold lines, and minor flaps hingedly connected to said bottom panel along respective third fold lines of joinder, characterized in that the length of at least one of said top and bottom panels is less than a distance between first fold lines of each said side panel so that the second and third fold lines are closer to the outermost articles thereby to reduce outward bowing. Preferably, the opposing first fold lines may be arcuate. More preferably, the lengths of both the top panel and the bottom panel may be lengthwise less than the distance between apexes of opposing first fold lines. According to an optional feature of the second aspect of the invention the top panel and the bottom panel may be of substantially equal length. According to another optional feature of the second aspect of the invention there may further comprise inwardly-inclined transition panels at respective ends of the side panels each formed by the first fold line and a fourth fold line positioned inwardly of the notional corner of the carton thereby to tighten the carton around the articles. Preferably, the fourth fold line may be arcuate to define a transition panel of an ellipsoidal shape. According to another optional feature of the second aspect of the invention the carton may have a handle structure, wherein the fourth fold line is placed across a panel forming the handle structure. According to a further optional feature of the second aspect of the invention the or each side panel may be separated from its adjacent side flap by the transition panel(s). A third aspect of the invention provides a blank for foiming a carton, the blank comprising a first panel for forming one of a top or bottom panel in the erected carton foldably adjoining a second panel for forming one side panel in the erected carton foldably adjoining a third panel forming the other of said top or bottom panel in the erected carton foldably adjoining a fourth panel for forming another side panel in the erected carton, side flaps foldably adjoining said second and fourth panels along respective first weakened lines of joinder each arcing toward said side flaps, major flaps foldably adjoining said first or third panel that serves as the top panel in the erected carton along respective second weakened lines of joinder, minor flaps adjoining said first of third panel that serves as the bottom panel in the erected carton along respective third weakened lines of joinder, and wherein a length of at least one of said first and third panels is lengthwise less than a distance between apexes of arcs of said second and fourth panels. Preferably, the lengths of both the first panel and the third panel may be lengthwise less than the distance between apexes of arcs of the second and fourth panels. According to an optional feature of the third aspect of the invention the first panel and the third panel maybe of substantially equal length. According to another optional feature of the third aspect of the invention there may further comprise inwardly-inclined transition panels at respective ends of the second and fourth panels each formed by a pair of the first weakened line of joinder and a fourth weakened line of joinder arcing toward a distal end of the second and fourth panel. A fourth aspect of the invention provides a carton for forming a blank for accommodating a plurality of articles comprising opposing top and bottom panels and opposing side panels adjoining one another forming a tubular structure, a pair of opposed side flaps hingedly connected to each of said side panels along opposed first fold lines, major flaps hingedly connected to said top panel along respective second fold lines, and minor flaps hingedly connected to said bottom panel along respective third fold lines, characterized in that the length of at least one of said top and bottom panels is less than a distance between first fold lines of each said side panel so that the second and third fold lines are closer to the outermost articles thereby to reduce outward bowing. Preferably, the opposing first fold lines may be arcuate. More preferably, the lengths of both the top panel and the bottom panel may be lengthwise less than the distance between apexes of opposing first fold lines. According to an optional feature of the fourth aspect of the invention the top panel and the bottom panel maybe of substantially equal length. According to another optional feature of the fourth aspect of the invention there may further comprise inwardly-inclined transition panels at respective ends of the side panels each formed by the first fold line and a fourth fold line positioned inwardly of the notional corner of the carton thereby to tighten the carton around the articles. Preferably, the fourth fold line may be arcuate to define a transition panel of an ellipsoidal shape. According to yet another optional feature of the fourth aspect of the invention the carton may have a handle structure, wherein the fourth fold line is placed across a panel forming the handle structure. According to a still further optional feature of the fourth aspect of the invention the or each side panel may be separated from its adjacent side flap by the transition panel. Beneficially, almond-shaped transition panels further facilitate a snug, secure end closure that is not easily deformed by bulging or blousing. Exemplary embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: FIGURE 1 is an isometric illustration of a carton having closure structure in accordance with the teachings of a preferred embodiment of the invention; FIGURE 2 is a plan view of a blank for forming the carton of Figure 1 ; and FIGURE 3 is an elevational view of the carton of Figure 1 from an end thereof. Throughout the drawings, the same reference numerals are used to denote the same or like features of the invention. Reference may generally be made simultaneously to Figure 1 and Figure 2 throughout the explanation of the invention that follows. A carton 10 having closure structure in accordance with the teachings of the preferred embodiment of the invention is shown in Figure 1. A blank 12 suitable for forming the carton 10 is shown in Figure 2. A tubular structure, shown in Figure 1, is formed from panels, which for convenience of reference, are referred to as top 22, a first side wall 24, bottom 26, and second side wall 20/28 panels hingedly connected together in series. The designation of orientation of these panels relates to the orientation of articles such as cans C that are packaged in the articles which is non-limiting. As shown in Figure 1, the upright orientation of a can C corresponds to the designation of the panels 22 and 26 as top and bottom panels, respectively, and the designation of panels 24 and bifurcated panel 20/28 as side panels. For convenience of explaining the blank 12, the panels that assume top and bottom panel disposition in the erected carton 10 are designated 22 and 26 and may be considered first and third panels in the blank. The end-most side panel is shown in bifurcated form 20/28 but does not necessarily have to be formed in that fashion to practice the teaching of the invention. For convenience of reference, the first side panel 24 in the blank may be considered the second panel and the outermost side panel may be considered the fourth panel. The orientation of each one of the pair of side panels with respect to one another and each one of the pair of top and bottom panels with respect to one another is inconsequential in the operation and teachings of the invention. For example, the top panel 22 may be used as the bottom panel 26 without departing from the teachings of the invention. A plurality of flaps and gusset structures form end closure for the tubular structure. In this embodiment, side flaps 25, 21/29 are adjoined to respective ends of the side panels 24, 20/28 along scored, perforated or otherwise weakened lines of joinder 55. For convenience of reference, these are referred to as first weakened lines of joinder. All of the weakened lines of joinder described herein maybe scored, perforated or otherwise weakened. Major flaps 23 are adjoined to the top (or first) panel along second weakened lines of joinder 45. Minor flaps 27 are adjoined to the bottom (or third) panel along third weakened lines of joinder35. Preferably, the first weakened lines of joinder 55 are arcuate, toward the side flaps 25, 21/29. In the erected carton, the arcuate lines of joinder 55 have the effect of making the carton 10 widthwise more narrow at the ends (as shown in Figure 3). In the preferred embodiment, the length L2 or L3 (that is, the distance between the second weakened lines of joinder 35 or third weakened lines of joinder 45) of at least one of the top and bottom panels 26, 22 is less than the length LI (that is, the distance between the apexes of the arcuate first weakened lines of joinder 55 so as to provide a tighter carton closure structure that is less prone to deformation by so-called blousing. This is because the lengths L2, L3 of the top 22 and bottom 26 panels are less than the distance LI between the apexes of the side walls 24, 20/28, so that the fold lines 45, 35 of the major 23 and minor 27 flaps, respectively, lie closer to or are even coincident with the chimes of cans C or similar articles that are packaged. This enables the package to be more tightly formed initially with less free or unencumbered major and minor flap area subject to the blousing effect. Accordingly, the side flaps 25, 21/29 are able to rest against the cans (C) while the major and minor flaps 23, 27 fit snugly against the top and bottom portions of the cans. In one class of embodiments, the carton end closure is made even more snug fitting with respect to the articles held within the carton through placement of a transition panel 50, 60 intermediate the side panels 24, 20/28 and the end walls of the carton. Each transition panel 50, 60 is formed from a first weakened line of joinder 55 and a fourth weakened line of joinder 58. Preferably, the two lines are outwardly arcuate with respect to the transition panels 50, 60, whereby the fourth weakened line of joinder 58 is arced toward the opposite end of the respective side panel. This enables the end structures to adhere even more closely to the packaged articles (such as cans C). In the preferred embodiment, the arcuate weakened lines 55, 58 define an elipse, whereby transition panels/gussets have ends that intersect at the corners of the carton. Thus, transition panels provide a smooth transition from the side panels to a more narrow end wall and structure, shown in more detail in Figure 3. The curvature of the lines of joinder 55, 58 forming the transition panel (or gusset) also adds to the vertical rigidity of the erected carton. This rigidity is useful in providing support for adhering the various flaps to one another upon carton end closure. In the preferred embodiment, the apex of each first weakened line of joinder 55 is disposed to coincide with the body of a corner article, at the end of a carton. Further, the apex of the fourth weakened line of joinder 58 may be disposed to coincide with the body of the corner article at its tangent with the side panel, so that at least part of the transition panel will abut a portion of the side of the article C. hi those embodiments with handle structure H, including a handle strap shown in Figure 2, the fourth weakened line of joinder 58 is adapted to be positioned across, or through, the strap. It will be recognised that as used herein, directional references such as "top", "base", "end", "side", "major" and "minor" do not limit the respective panels to such orientation, but merely serve to distinguish these panels from one another . Any reference to hinged connection or lines of joinder should not be construed as necessarily referring to a single fold line only: indeed, it is envisaged that hinged connection can be formed from one or more of one of the following, a score line, a frangible line or a fold line, without departing from the scope of invention. It should be understood that various changes may be made within the scope of the present invention, for example, the size and shape of the transition panels and/or lines of joinder may be adjusted to accommodate articles of differing size or shape, or alternative top and base closure structures may be used. The carton may accommodate more than one article in different arrays.

Claims: CLAIMS 1. A carton comprising opposing top and bottom panels and opposing side panels adjoining one another forming a tubular structure, side flaps foldably adjoining said side panels along respective first weakened lines of joinder each arcing toward said side flaps, major flaps foldably adjoining said top panel along respective second weakened lines of joinder, and minor flaps adjoining said bottom panel along respective third weakened lines of joinder, and wherein a length of at least one of said top and bottom panels is less than a distance between apexes of arcs of said side panels. 2. The carton of claim 1, wherein the lengths of both said top panel and said bottom panel are lengthwise less than said distance between apexes of arcs of said side panels. 3. The carton of claim 1 or claim 2, wherein said top panel and said bottom panel are of substantially equal length. 4. The carton of any of claims 1 to 3, further comprising inwardly-inclined transition panels at respective ends of said side panels each formed by a pair of said first weakened line of joinder and a fourth weakened line of joinder arcing toward a distal end of said side panel. 5. A carton for accommodating a plurality of articles comprising opposing top and bottom panels and opposing side panels adjoining one another forming a tubular structure, a pair of opposed side flaps hingedly connected to each of said side panels along opposed first fold lines, major flaps hingedly connected to said top panel along respective second fold lines, and minor flaps hingedly connected to said bottom panel along respective third fold lines of joinder, characterized in that the length of at least one of said top and bottom panels is less than a distance between first fold lines of each said side panel so that the second and third fold lines are closer to the outermost articles thereby to reduce outward bowing. 6. A carton as claimed in claim 5 wherein the opposing first fold lines are arcuate. 7. The carton of claim 6, wherein the lengths of both said top panel and said bottom panel are lengthwise less than said distance between apexes of opposing first fold lines. 8. The carton as claimed in any of claims 5 to 7, wherein said top panel and said bottom panel are of substantially equal length. 9. The carton as claimed in any of claims 5 to 8, further comprising inwardly- inclined transition panels at respective ends of said side panels each formed by said first fold line and a fourth fold line positioned inwardly of the notional corner of the carton thereby to tighten the carton around the articles. 10. The carton as claimed in claim 9 wherein the fourth fold line is arcuate to define a transition panel of an ellipsoidal shape. 11. A carton as claimed in claim 9 or claim 10, having a handle structure, wherein the fourth fold line is placed across a panel forming the handle structure. 12. A carton as claimed in any of claims 9 to 11 wherein the or each side panel is separated from its adjacent side flap by said transition panel(s). 13. A blank for forming a carton, the blank comprising a first panel for forming one of a top or bottom panel in the erected carton foldably adjoining a second panel for forming one side panel in the erected carton foldably adjoining a third panel forming the other of said top or bottom panel in the erected carton foldably adjoining a fourth panel for forming another side panel in the erected carton, side flaps foldably adjoining said second and fourth panels along respective first weakened lines of joinder each arcing toward said side flaps, major flaps foldably adjoining said first or third panel that serves as the top panel in the erected carton along respective second weakened lines of joinder, minor flaps adjoining said first of third panel that serves as the bottom panel in the erected carton along respective third weakened lines of joinder, and wherein a length of at least one of said first and third panels is lengthwise less than a distance between apexes of arcs said second and fourth panels. 14. The blank of claim 13 wherein the lengths of both said top first panel and said third panel are lengthwise less than said distance between apexes of arcs of said second and fourth panels. 15. The blank of claim 13 or claim 14 wherein said first panel and said third panel are of substantially equal length. 16. The blank of any of claims 13 to 15 wherein transition panels are disposed at respective ends of said second and fourth panels each formed by a pair of said first weakened line of joinder and a fourth weakened line of joinder arcing toward a distal end of said second and fourth panel. 17. A blank for forming a carton for accommodating a plurality of articles comprising opposing top and bottom panels and opposing side panels adjoining one another forming a tubular structure in a set up carton, a pair of opposed side flaps hingedly connected to each of said side panels along opposed first fold lines, major flaps hingedly connected to said top panel along respective second fold lines, and minor flaps hingedly connected to said bottom panel along respective third fold lines, characterized in that the length of at least one of said top and bottom panels is less than a distance between first fold lines of each said side panel so that the second and third fold lines are closer to the outermost articles thereby to reduce outward bowing in a set up carton. 18. A blank as claimed in claim 17 wherein the opposing first fold lines are arcuate. 19. The blank of claim 18, wherein the lengths of both said top panel and said bottom panel are lengthwise less than said distance between apexes of opposing first fold lines. 20. The blank as claimed in any of claims 17 to 19, wherein said top panel and said bottom panel are of substantially equal length. 21. The blank as claimed in any of claims 17 to 20, further comprising inwardly- inclined transition panels at respective ends of said side panels each formed by said first fold line and a fourth fold line positioned inwardly of the notional corner of the carton thereby to tighten the carton around the articles. 22. The blank as claimed in claim 21 wherein the fourth fold line is arcuate to define a transition panel of an ellipsoidal shape. 23. A blank as claimed in claim 21 or claim 22, having a handle structure, wherein the fourth fold line is placed across a panel forming the handle structure. 24. A blank as claimed in any of claims 21 to 23 wherein the or each side panel is separated from its adjacent side flap by said transition panel.

Inventors: OLIFF JAMES R, OLIFF, JAMES, R
Applicants: MEAD CORP, OLIFF JAMES R, OLIFF, JAMES, R, THE MEAD CORPORATION
Application year: 2000
Main classification: B65D71
IPC codes: B65D5, B65D71