GB2257686A - Containers - Google Patents

Abstract

A flat-topped carton for storing liquids has a weakened area (25) defined in a top surface (15) thereof. A sealing fin (28) of the carton is folded over and secured to said area (25) so as to lie flat on the top surface (15). When it is desired to open the carton the fin (28) is lifted away from the surface (15), taking with it the weakened region (25), and so defining an opening (31, Fig. 5). <IMAGE>

Description

Containers The present invention relates to containers and in particular, but not exclusively, to cartons made from cardboard, paper board or similar lightweight foldable sheet material such as are used for storing liquids such as milk, fruit juices, detergents and the like.

In order to allow the contents of a carton to be emptied, an opening must first be made in the carton.

This has up to now been achieved in a number of ways.

In flattened gable-top cartons such as are commonly used for storing milk, one end of the gable-top is first pulled apart and inner panels of the top pulled out to define a pouring spout through which the contents may be emptied. In practice, however, such an opening may be difficult to form by a user.

In another type of carton, such as may be used to store fruit juices for example, the top closure of the carton comprises triangular flaps extending at each end of the top panel of the carton and which are normally folded down against the side of the carton. To open the carton, a flap is released from the side of the carton and cut or torn to define an opening through which the contents may be poured. Again, a user may find it difficult to produce a satisfactory opening in the carton in this way.

More recently it has been proposed to form a hole in a carton wall during manufacture, fit a plastics pouring spout in the hole and close it by a screw cap. The contents are then emptied in use simply by removing the cap. This form of opening, while being simpler to use, is more difficult and expensive to manufacture.

According to a first aspect of the present invention there is provided a container having a closure comprising a weakened portion for defining an aperture and an opening member, overlying and secured to said weakened portion, whereby when said opening member is lifted, said weakened portion fails and creates said aperture.

Thus by lifting an opening member, which is preferably an integral part of the container, a weakened portion in the container is ruptured to create an opening in the container through which the contents may be emptied.

Not only is such an aperture more easily made by a user, but by virtue of overlying the weakened area, the opening means protects the weakened area in use. It is also considerably simpler to manufacture than certain known closures.

Preferably the container is a carton formed from, or having at least a closure section formed from, a blank of cardboard, paperboard or similar flexible lightweight sheet material. The blank material may be coated on one or both sides with a film of a thermoplastics material such as polythene or polypropylene. The invention also extends to such a blank and provides, from a second aspect, a blank of cardboard, paperboard or similar lightweight flexible sheet material, said blank comprising a plurality of closure panels for forming a closure of a carton, said closure panels including a weakened portion for defining an aperture and a panel arranged such that upon erection it may be positioned so as to overlie said weakened portion to be secured thereto.

For ease of use, the closure is preferably provided in an upper surface of the container or carton, although it could be provided on other surfaces if appropriate.

Advantageously, the opening means is formed as a hinged flap or panel which may be gripped by a user at its free end and pivoted away from the surface of the container or carton to rupture the weakened portion, which remains attached to the flap, to define the aperture.

Preferably the carton closure is of the type comprising first and second top-forming panels interconnected by tuck forming panels, with sealing panels hingedly connected to the top of these panels. In such a carton, the weakened area is preferably defined in the first top forming panel and the opening flap defined by, or by an extension of, a sealing panel provided along the top of the first or second top-forming panel, this panel being folded over the weakened portion of the top forming panel and secured thereto by adhesive, for example.

Preferably the sealing panels provided on both top forming panels are extended and joined together, for example by heat sealing, to form the opening flap.

Advantageously, the extended sealing panels are substantially the same size as the first top-forming panel whereby, when folded into position, they cover substantially the whole of that panel.

It will be appreciated that depending on the geometry of the carton and the closure panels, the erected carton may be gabled topped, or flat topped. Preferably, however, the height of each of the top forming panels is substantially half the width of the carton such that when the flap is folded over into position, the top of the carton lies substantially flat.

If it is found desirable, means may be provided for securing the opening flap to the carton outside the weakened portion so as more positively to secure it in position and to relieve stresses on the weakened portion in use. Such additional securing means may be in the form of an adhesive, or straps extending between the flap and the carton walls for example.

The weakened region may be of any desired shape and size and may be positioned at any suitable location. It need not be detached completely from the container or carton by the opening member to define the aperture, and could remain attached to it by a hinged joint for example. In the preferred embodiment described above, the weakened area may extend from the hinge line between the first top forming panel and its respective flap forming sealing panel such that when the opening flap is operated, the weakened region remains attached to and pivots about the hinge line.

The weakened region of the carton is preferably formed by partially cutting through the thickness of the blank material. The blank material will normally be coated both sides with a film of thermoplastics material, for sealing purposes. In one embodiment, the blank is cut on both sides, so as to penetrate the film on both sides, to facilitate formation of the opening.

Preferably the cuts are offset laterally from one another, the cut formed on the inner surface being formed within the profile of the outer cut. This offset provides a labyrinthine path for liquid in the container, whereby leakage through the cuts in the carton wall at this location can be prevented. It also provides for the correct delamination of the blank material when the opening is created. Such cutting can advantageously be performed in a "flat bed" cutting and creasing machine using opposed "male" and "female" cutting rules. The male rule cuts through approximately half the thickness of the board from the outer surface and the female rule, which lies within the profile of the male rule, cuts through half the thickness of the board from the other side.

It may be possible however to dispense with cutting the inner surface of the blank if the cut from the outer surface can be made sufficiently accurate and deep, so as not to break the inner thermoplastics film, and so maintain a complete seal. One possible means by which this may be achieved may be by laser cutting the blank material.

The cut or cuts formed in the blank are preferably continuous, but may be intermittent, in the form of perforations, if this is found to be adequate or desirable.

From the above it will be clear that the invention also extends to a method of manufacturing a carton comprising the steps of providing a blank in accordance with the second aspect of the invention, erecting the blank such that a closure panel is in a position relative to the weakened region from which it may be moved to overlie said weakened region, and moving said panel over the weakened region and securing it thereto.

The weakened region may be formed in the blank by the methods as described above, for example.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a plan view of the upper part of a carton blank in accordance with the invention; Fig. 2 is a sectional view taken along the line A-A of Fig. 1; Fig. 3 is a view of a carton embodying the invention, in an intermediate stage of construction; Fig. 4 is a view of the same carton, completed; and Fig. 5 is a view of the carton when opened.

Referring to Fig. 1, there is shown the upper closure forming part of the outer surface of a carton blank 1 for forming a flat top carton as shown in Fig. 4. The blank 1 is a laminate of a paperboard core 2 coated on both surfaces with a thin polythene film 3 (see Fig. 2).

The blank 1 comprises four, hingedly interconnected wall-forming panels 4,5,6,7, an edge sealing panel 8, and an array of closure panels 9 hingedly attached to the tops of these panels along respective hinge lines 10-14. The closure panels 9 comprise first and second top forming panels 15,16, which are hingedly interconnected to each other via respective arrays of triangular tuck-forming panels 17,18. Sealing panels 19-23 are hingedly connected to the upper edges of these panels 15-18 along a hinge line 24. Such an arrangement of closure panels is well known in the art except for the extended sealing panels 19,21, the purpose of which will become apparent later.

The first top-forming panel 15 is provided with a weakened region 25 for creating an opening in the top of the carton as will be described later. The weakened region 25 extends in a tongue-like manner from the hinge line 24 and is defined by outer and inner continuous cut lines 26,27, which are offset from one another. The weakened region 25 is formed in the central part of the panel 15, but could equally be formed in another position, for example at an end of the panel 15. Indeed it may be preferable to provide it in such a position so that when pouring, the carton may be gripped by its diagonally opposed edges, which may give a more rigid arrangement for pouring.

As can be seen from Fig. 2, the cuts 26,27 extend through approximately half the thickness of the blank 1 and puncture the respective thermoplastic films 3. The cuts are formed in a flat bed machine by male and female cutting rules, cooperating on opposite sides of the blank material.

To form the closure, the blank 1 is first assembled into a tubular blank by folding about the vertical hinge lines between the wall forming panels 4-7 and securing the sealing strip 8 to the inner edge of panel 4. The top forming panels 15,16 are then pushed together, with the tuck forming panels 17,18 being folding inwardly between the panels 15,16, until the sealing panels 19-22 form an upstanding fin or flap 28, as shown in Fig. 3.

The various sealing panels of the flap 28 are then secured together, for example by ultrasonic welding.

The extensions of the sealing panels 19,21 are also secured together as shown. As can be seen, at this stage the carton has a shallow gable top.

An adhesive is then applied to the surface of the weakened region 25 and the flap 28 folded down about the hinge line 24 to cover and adhere to the weakened region 25. Any suitable adhesive, for example a hot melt adhesive, may be used, and it may even be possible to ultrasonically weld the flap 28 to the weakened region 25. Additional means may be provided to secure the flap to the carton, for example strips of board applied over the edge of the flap 28 and sides of the carton 5,7.

When the flap 28 is folded into position the top of the carton assumes a generally flat shape. As can be seen, the height of the sealing panels 19,21 forming the flap 28 is approximately equal to the width of the side wall forming panels 5,7, so that the flap 28 substantially covers the top-forming panel 15. In this position the weakened region 25 is protected by the flap 28, and cartons may be stacked one on the other.

When it is desired to open the carton, a user merely lifts the free edge 29 of the flap 28, which pivots about the hinge line 24. As it is moved to a vertical position, it pulls the weakened region 25 upwardly, this region rupturing along the cut lines 26,27, as can be seen in Fig. 5. A tongue 30 of material remains attached to the flap 28, and a hole 31 is formed in the surface 15, through which the carton contents may be poured. It will be seen that the weakened region 26 delaminates on opening to leave a land 32 of polythene film and board around the opening 31.

It will be clear that the weakened region 25 may be defined in other ways, for example by a cut formed on the outer surface of the blank only. Also the region 25 may be of a different shape and size to that shown. It will also be appreciated that the opening need not be formed in the top surface of the carton. It might be possible, for example, to provide the weakened region in an edge region of the side wall of the carton, and extend the adjacent front wall panel over the edge region and secure it to the weakened region. In a carton of the type having a top closure comprising triangular flaps folded down over the tops of opposed side walls, the weakened area could be formed in the side wall area arranged under a flap, so that when a flap is lifted, an opening is created in an upper side wall of the carton.

Claims (17)

Claims

1. A container having a top closure comprising two mutually opposed top-f.orr. panels which are interconnected by way of a sealing fin which is formed by the incerconnection of two sealing flaps hingedly connected to the respective top-forming panels, a weakened area being defined in one of said top-forming panels for forming an aperture therein, and said sealing fin being folded down over said one top forming panel and secured to said weakened area therein, whereby when said sealing fin is lifted said weakened area fails and is also lifted, to form said aperture.

2. A container as claimed in claim 1, wherein said sealing fin is dimensioned to substantially cover said one top-forming panel.

3. A container as claimed in claim 1 or 2, which is flat-topped.

4. A container as claimed in any preceding claim, wherein said sealing fin is also secured to said one top-forming panel outside of said weakened area.

5. A container as claimed in any preceding claim, wherein said weakened area extends from the hinge line between the said one top-forming panel and its associated sealing flap.

6. A container as claimed in any preceding claim, wherein said weakened area is formed by partially cutting through the thickness of the container material.

7. A container as claimed in claim 6, wherein the weakened area is defined by laterally offset cuts in the respective inner and outer surfaces of the container material.

8. A container blank of cardboard, paperboard or similar lightweight flexible sheet material, comprising first and second top-forming panels having sealing flaps hingedly connected thereto at their respective distal edges, a weakened area being defined in one of said topforming panels for forming an aperture therein, and said sealing flaps being interconnectible to form a sealing fin arranged so that, upon erection, it may be positioned to overlie said weakened area and be secured thereto.

9. A blank as claimed in claim 9, wherein the length of at least one of said sealing flaps is substantially the same as the height as said one top-forming panel.

10. A blank as claimed in claim 8 or 9, wherein the width of at least one of said sealing flaps is substantially the same as that of said one top-forming panel.

11. A blank as claimed in any of claims 8 to 10, wherein the height of each top-forming panel is substantially half the width of the erected container.

12. A blank as claimed in any of claims 8 to 11, wherein said weakened area extends from the hinge line between the said one top-forming panel and its associated sealing flap.

13. A blank as claimed in any of claims 8 to 12, wherein said weakened area is formed by partially cutting through the thickness of the container material.

14. A blank as claimed in any of claims 8 to 13, wherein the said weakened area is defined by laterally offset cuts in the respective inner and outer surfaces of the container material.

15. A blank as claimed in any of claims 8 to 14, which blank is thermoplastics coated.

16. A container substantially as hereinbefore described with reference to the accompanying drawings.

17. A container blank substantially as hereinbefore described with reference to the accompanying drawings.