GB2088338A - Carton end closures - Google Patents

Abstract

A gable top carton with preferably six walls has a top end closure defined by two major end flaps 24, 26 brought together over bellows forming panels 34 which extend across the ends of two adjacent wall panels 16, 18. To accommodate the angle between panels 16, 18, the bellows forming panels are folded into two portions 34A, 34B and an upstanding rib or fillet 50. A flat bottom end closure likewise has major end flaps 28, 30, and bellows-forming panels folded into portions 32A, 32B and 46. <IMAGE>

Description

SPECIFICATION Carton end closures This invention relates to cartons, and more particularly to the end closures of cartons which are produced in a tubular form.

Cartons in the form of a square or rectangular tube comprising an array of four side walls hinged one to the next are well known. A particular form of end closure has a major end flap hinged to the end of each of two opposing side walls of the rectangular tube. Hinged to each of the other two opposing side walls, between the major end flaps, is a triangular or trapezoidal panel, with two triangular wings each hinged on one side to the triangular or trapezoidal panel, and on another side to a respective major end flap. In forming such an end closure, the two major end flaps are brought together, and at the same time the triangular or trapezoidal panels hinge inwardly under the major end flaps, forming a bellows with the triangular wings.Usually, the board material from which the carton is formed has coatings of a sealable plastics material such as polyethylene, and the end closure area is preheated prior to folding and compressing to fuse the plastics material and seal the end closure.

The end closure thus formed can either be flat or the opposing major end flaps may be made slightly longer so that when brought together they trap tabs on the third sides of the triangular wings and form a "gable top" end closure for the carton.

Such gable top end closures can be adapted to form a pouring spout when the end closure is opened for liquid such as milk or fruit juice within the carton.

The following patent specifications are representative of the large number which describe such cartons: GB 977700, GB 990835, GB 1003182, US 3024959, US 3120335 and US 4012997.

A problem with all such cartons to date has been that they have all had square or rectangular tubular cross-sections. An object of the present invention, therefore, is to increase the variety of such cartons available.

A further problem with the known cartons is that certain areas are not always as strong as desired. For example, the contents can cause the sidewalls to bow outwards and this leads to the cartons being wedged together when packed side by side in a box, so that they are difficult to unpack.

The present invention provides a carton comprising an array of wall panels hinged one to the next and with the end panels of the array hinged together to form a tube; two generally opposing wall panels having respective major end flaps hinged thereto at one end of the tube, the major end flaps being arranged to be brought together when closing the end of the tube; a bellows-forming panel hinged at said end of the tube to a wall panel intermediate those which have the major end flaps; the bellows-forming panel having generally triangular wings extending between and hinged to edges of the major end flaps and edges of the bellows-forming panel, whereby the major end flaps can be brought together over the bellows-forming panel with the bellows-forming panel forming a bellows together with the wings, to form an end closure for the tube; characterised in that there are five or more wall panels, and in that at least one said bellowsforming panel extends across the end of and is hinged to two adjacent wall panels intermediate the wall panels which have the major end flaps, and in that this bellows-forming panel is provided with fold means arranged to take up excess material thereof when said two adjacent walls panels are at an angle to each other.

It is thus possible to provide a carton with more than four side wall panels. Moreover, for a given capacity of carton, the wall panels will tend to be smaller, and will thus exhibit less of a tendency to bow.

A preferred number of walls panels is six, with two said bellow-forming panels, each having a said fold means and a pair of said triangular wings, and extending between the major end flaps across two adjacent walls panels one on each side of the carton.

As with the prior art, such an end closure can be arranged to be flat when made up, or can form a gable top. Thus cartons may be made with bottom end closures of the flat type and top end closures of the gable top type.

Preferred embodiments of cartons according to the invention will now be described by way of example, with reference to the accompanying drawings, wherein: Fig. 1 is a plan view of a blank for making a carton, Fig. 2 shows the bottom end closure of the carton partially erected, Fig. 3 is a view of the completed bottom end closure from beneath, Fig. 4 shows the top end closure partially erected, and Fig. 5 shows the top end closure completed.

The carton is formed from a blank of foldable board material having a polyethylene or other heat sealable coating on both surfaces. Depending on the intended contents, a barrier layer of aluminium may also be included in the material. Referring to Fig. 1, the blank comprises six side walls 10, 12, 14, 1 6, 1 8, 20, which are hinged side by side one to another in an array. In Fig. 1, the single dotdashed lines represent creases which fold in one direction, while the double dot-dashed lines represent creases which fold in the opposite direction. On the free side of the wall panel 1 0 there is hinged a glue flap 22, and the first step in erecting the carton is to glue the flap 22 to the panel 20 to make the blank into a flattened, tubular form in which it can be sent home to the user.

At each end of each panel 10 to 20, there is provided a flap for forming an end closure. The wall panels 14 and 20 have major end flaps 24.

26, 28, 30 hinged thereto. The end flaps at each end of the pairs of panels 10, 12 and 16, 18 when taken together form bellows-forming panels 32, 34 each of which is provided with a pair of triangular wing panels 36, 38. These are hinged on one side by an oblique hinge line 40, 42, to the bellows-forming panel 34, 36; and on another side (at least when the blank is in the tubed condition) to a respective one of the major end flaps 24 to 30. It is these triangular wings which cause the bellows action of the bellows-forming panels.

In a conventional carton of this type, the bellows-forming panels would be hinged to only one wall panel rather than to a pair of wall panels.

To aliow the pair of wall panels to hinge relative to each other, each bellows-forming panel 32 is provided with two creases 43, 44, giving a triangular fillet 46 in the bellows-forming panel 32 between the creases 43, 44. This fillet 46 divides the bellows-forming panel 32 into two parts, 32A and 32B, and in use it allows one part 32A to lie partially over the other part 32B and takes up some of the material between these two parts, allowing the pair of panels 10, 12 or 1 6, 1 8 to lie at an angle to each other.

Figs. 2 and 3 show how this happens. First of ail, the tubed, flattened blank is opened out into a hexagonal cross-section. Then tha major end flaps 28, 30 are pushed towards each other, while at the same time the panels 32B are pushed inwardly. The panels 32A also move in at the same time, but the panels 32A, 32B, with the triangular fillet 46, fold in concertina fashion. The panel 32B then lies partially underneath the panel 32A with the fillet 46 between them.Fig. 2 shows this action on the side of the walls 16, 18 but exactly the same happens on the side of the walls 10, 12. When ail the end closure panels approach a flat condition, an end portion 30A of the major end flap 30 passes underneath an end portion 28A of the major flap 28, and is sandwiched between the flap 28 and the adjacent triangular wings 36. Radiant heat is now applied to the entire region of the bottom end closure, causing the polyethylene on the surfaces of the various end flap panels to be brought to a fusible condition. The flaps are then folded and compressed to fuse the heated heat-sealable surfaces together, forming a leak proof closure.

Other sealing methods can be used, such as ultrasonic welding.

Referring now back to Fig. 1 , the formation of the gable top end closure will be described.

For the gable top, the bellows-forming portion 34 have triangular wings 38 as before. However, the panel 34 is interrupted by three creases 52, 54, 52 dividing it into two 34A, 34B which correspond with the panels 32A, 32B of the bottom end closure. Between these panels 34A, 34B are two fillets 50 which are hinged to each other by the crease line 54, and to respective ones of the panels 34A, 34B by the crease lines 52. As can be seen from Figs. 4 and 5, the top end closure is erected by pushing towards each other the major end flaps 24, 26. As this happens, the panels 34A, 34B hinge inwardly in bellows fashion with the triangular wings 38.Since the pairs of wall panels 1 6, 1 8 and 10, 12 are angled to each other, at the same time the fillets 50 are folded flat against each other about the hinge line 54 and form, as seen in Fig. 5, an upstanding rib between the bellows forming panels 34A, 34B. When the major end flaps 24, 26 have been brought into the gable top forming position as shown in Fig. 5, extension tabs 24', 26' thereof sandwich both the top ends of the rib-forming fillets 50 and extension tabs 38' of the triangular wings 38. Heat and pressure is then applied along the line of the extension tabs 24', 26' to seal this sandwich together, which makes the gable top end closure leak proof by fusing together the polyethylene on the surface of the board material.At the same time, the top is finished off neatly by sealing together tabs 24", 26" which are provided on the major end flaps 24, 26 beyond the extension tabs 24', 26'. Other sealing methods can be used for instance ultrasonic welding which has the advantages that it is possible to seal through a contaminated area, and that it can be used even if the contents of the carton become explosive when exposed to heat.

This gable top end closure is easily opened by a consumer by inserting the thumbs underneath the major end flaps 24, 26 to separate the sandwich between the tabs 24', 27' at one end of the gable top. The sonsumer then grips the rib-forming fillets 50 and pulls them outwards. When this has been done, the two fillets 50 form a pouring spout for liquid from within the carton. This is an improvement on the conventional rectangular gable top carton, where it is sometimes difficult to pull out the pouring spout after the sandwich has been forced apart.

The fillets 50 also rigidify the top end closure to make it stronger, and thus instead of using the fillets 50 as a pouring spout, it becomes possible to weld a separate pouring spout into position on one of the major end flaps 24, 26. Such a pouring spout could be provided with a screw thread and a complementary cap so as to be reclosable if desired. Alternatively, the stronger closure would ailow a pump to be passed through one of the major end flaps 24, 26 so that the contents could be dispensed in measured volumes. Or it becomes possible to open a filled carton by punching a stopper through one of the flaps 24, 26.

It will be apparent that the invention is also applicable to other polygonal cross-section cartons. For example, it would be possible to make a five sided carton by having one side which has conventional bellows-forming end flaps (i.e. as in a conventional rectangular carton) and, opposing that, two side wall panels which have a composite bellows-forming panels like 34 and 32. Moreover, it would be possible to have cartons with more than six sides, for example octagonal cartons, by providing the bellows-forming flaps 34, 32 with more creases to provide more intermediate fillets 46, 50 to take up the additional material required to allow the increased number of walls to assume angles relative to each other.For a given size of carton, the more wall panels there are the less the contents will cause the wall panels to bow, though obviously increasing the numbers of panels does increase the complexity of forming the carton, Of course, the carton need not have the two different types of end closure described.

Alternatively it is possible to make an open topped carton by using only the bottom half of the blank shown in Fig. 1 cut off at the line AA. This would give a tube or a relatively deep tray, though of course the side walls can be made any desired height. The top edge of the side walls can be provided with turn over flaps hinged along the line AA, and sealed to either the inner or outer surfaces of the side walls. These would provide reinforcing and give the top edges a continuous plastics coating with no raw board edge.

If such a tray were made with the blank exactly as shown below the line A-A in Fig. 1, this would give a straight-sided container, but it is possible to produce a tray or tub with slightly diverging sides by using a blank in which the wall panels 10 to 20 increase in width towards the top. This will enable a stack of the resulting open topped cartons to be nested one inside another. Such a tray or tub might, for example, be used for ice cream. A lid may be provided for such a tray or tub, for example of folded board or of thermoformed material.

It is also possible to make gable top type cartons with sloping sides in the same manner.

The free edge of the glue flap 22 of the carton blank may if desired be skived and hemmed to prevent the liquid contents of the carton wicking into the board material.

Claims (14)

1. A carton comprising an array of wall panels hinged one to the next and with the end panels of the array hinged together to form a tube; two generally opposing wall panels having respective major end flaps hinged thereto at one end of the tube, the major end flaps being arranged to be brought together when closing the end of the tube; a bellows-forming panel hinged at said end of the tube to a wall panel intermediate those which have the major end flaps; the bellowsforming panel having generally triangular wings extending between and hinged to edges of the major end flaps and edges of the bellows-forming panel, whereby the major end flaps can be brought together over the bellows-forming panel with the bellows-forming panel forming a bellows together with the wings, to form an end closure for the tube; characterised in that there are five or more wall panels, and in that at least one said bellowsforming panel extends across the end of and is hinged to two adjacent wall panels intermediate the wall panels which have the major end flaps, and in that this bellows-forming panel is provided with fold means arranged to take up excess material thereof when said two adjacent wall panels are at an angle to each other.

2. A carton according to claim 1 having two said bellows-forming panels extending across the ends of and hinged to respective pairs of said intermediate wall panels, said respective pairs opposing each other on opposite sides of the wall panels with the major end flaps.

3. A carton according to claim 2 having six wall panels.

4. A carton according to any one of the preceding claims in which the major end flaps and the bellows-forming panel or panels form a flat end closure at said end of the tube.

5. A carton according to any one of claims 1 to 3 in which the major end flaps and the bellowsforming panel or panels form a gable top end closure at said end of the tube.

6. A carton according to claim 5 wherein the fold means in the bellows-forming panel provides an upstanding rib or fillet therein.

7. A carton according to claim 6 wherein the rib or fillet is trapped between the major end flaps where they are brought together to close the end of the tube.

8. A carton according to claim 6 or claim 7 wherein the rib or fillet is adapted to form a pouring spout when the carton is opened at said end of the tube.

9. A carton according to any one of claims 5 to 8 wherein the other end of the tube has an end closure comprising an opposing pair of said major end flaps and at least one said bellows forming panel extending across an adjacent pair of said intermediate wall panels.

10. A carton according to claim 9 wherein the end closure at the other end of the tube is flat.

11. A carton according to claim 4 in the form of a tray or tub.

12. A carton substantially as decribed herein with reference to the accompanying drawings.

1 3. A carton according to any one of claims 1 to 10 or claim 12, made of liquid-tight board material and filled with a liquid.

14. A blank of foldable board material, creased for forming a carton according to any one of the preceding claims.

1 5. A blank according to claim 14, coated with a heat sealable coating.

1 6. A blank substantially as described herein and as shown in Fig. 1 of the accompanying drawings.