GB2325919A

GB2325919A - Crash lock base carton

Info

Publication number: GB2325919A
Application number: GB9711638A
Authority: GB
Inventors: Stephen John Coates; Roy James Deadman
Original assignee: Smurfit Ltd
Current assignee: Smurfit Kappa UK Ltd
Priority date: 1997-06-05
Filing date: 1997-06-05
Publication date: 1998-12-09
Also published as: GB9711638D0

Abstract

A crash lock base carton 1 is formed which has a hole in its base. The carton is formed from a blank with a tubular body, tabs 11, 13, 15, 17 connected to each side panel 1, 3, 5, 7 forming the base. Two of the tabs 13, 15 are provided with an interlocking mechanism 21, 23 to help maintain the carton in its erect state. The interlocking mechanism may comprise a nose 21 engaging within a hole 23. Side wall tab 19 is glued to wall 7 and comer portions 25, 27 of opposing tabs 11, 15 are glued to adjacent tabs 13, 17 to form a flat partly formed carton. The carton is then finished by opening out the partly formed carton, the base forming and locking automatically. The carton may have a lid (not shown) and a cut away portion 31.

Description

IMPROVEMENTS IN OR RELATING TO CARTONS AND CARTON BLANKS The invention relates to cartons and carton blanks therefor, particularly so-called crash lock cartons.

Crash lock cartons are well known. The term refers to a carton that is erected by "crashing" two corners together, by hand or machine. They may be formed from a carton blank having a row of four side pieces, and four tabs, each side piece adjoining a corresponding tab. The side faces and tabs are formed out of a single sheet of cardboard, and divided one from the other by score lines. To form a carton from the carton blank, the first step is to glue the first and fourth pieces side pieces together, using an additional tab, to form a rectangular tube. Some of the tabs may be also be glued to adjoining tabs. At this stage, the half-formed carton can still be packed flat for easy storage.

When the carton is finally required, the corners at the ends of the flat tube are brought together and the carton then automatically forms and locks ("crash lock"). In detail , the four side pieces of the part formed carton are re-erected to form the rectangular tube, and the four tabs are interlocked together at the centre of the base so that the carton is held in a cuboidal form by this interlocking of the tabs.

According to a first aspect of the present invention there is provided a carton blank comprising four side pieces in a line, the side pieces each having a length measured along the line, wherein each side piece has a tab arranged laterally of it, the sum of the widths, measured perpendicularly to said line, of alternate tabs being less than the length of the side piece located between the side pieces associated with said alternate tabs, the carton blank is foldable to form a carton with the said side pieces forming the sides of the carton and the said plurality of tabs forming the bottom of the carton, and two of the tabs have an interlocking mechanism adapted to hold the two tabs together in the carton folded from the blank.

This improved carton blank is advantageous because it uses less material by virtue of the narrower tabs.

Such a saving of material can give rise to very significant economic benefits when large numbers of cartons are produced. However, simply narrowing the tabs alone would not be sufficient, because such narrower tabs would not lock to each other sufficiently well for the carton manufactured from such a blank to be sufficiently stable and strong in use. The invention overcomes this difficulty by means of the interlocking mechanism.

The carton blank is preferably formed from a single piece of board and many such carton blanks can be cut from a single sheet of board.

Preferably, the interlocking mechanism comprises a nose on one of the tabs and a hole in an adjacent tab, adapted to engage one in the other when the finished carton is formed.

A locking tab is preferably provided extending into or towards the hole to lock the nose in place.

Preferably, the nose is arranged to pass under a portion of the tab having the hole and the locking tab is arranged to pass under a portion of the tab having the nose, whereby the nose and tab are forced to be at slightly different angles to the bottom of the erected carton ensuring that the nose and tab engage one against the other to lock the carton.

In embodiments, the nose may have an engagement edge extending substantially parallel to the line of the side pieces and the locking tab may have an engagement edge substantially perpendicular to said line, arranged such that the two engagement edges engage one against the other in a substantially, but not exactly parallel arrangement in the locked position of the carton formed from the blank.

In order to enhance the rigidity of the carton formed from the blank, it is preferred to form two interlocking mechanisms of the type described above by forming noses and holes on alternate tabs.

For an improved display of products within the finished carton, portions of the rectangular side pieces may be cut away.

In order that the carton blank may be easily folded, it is preferably scored along the lines dividing the side pieces from each other and from the tabs. An additional tab is preferably provided in the line of the side pieces to permit the carton blank to be glued together to form an open rectangular tube in the first stage of producing the carton from the carton blank. The open rectangular tube can then be folded flat for storage and transport until such time as the carton is to be erected.

When required, in addition to having the plurality of tabs which form the carton bottom, a top piece or pieces may be provided which form a lid or top in the finished carton.

Preferably, one or more of the tabs includes a portion defining a gluing surface for gluing the tab to an adjacent tab. In order that the carton may still be folded flat after gluing to form the open rectangular tube, a score line is preferably provided between the portion defining the gluing surface and the rest of the tab. In some embodiments, the score line is perforated for greater flexibility. In embodiments, such gluing surface-defining portions are provided on the second and fourth tabs, to glue the first and second tabs and the third and fourth tabs together respectively. In such an arrangement, the interlocking mechanism is preferably provided on the second and third tabs to lock those tabs together. In embodiments having two interlocking mechanisms, the second interlocking mechanism would then be formed on the first and fourth tabs. Such a glued blank easily folds about the fold lines between the first and second side pieces on the one hand and the third and fourth side pieces on the other to form a flattened rectangular tube which can be easily erected to form a strong carton.

The flat part-formed carton formed by gluing the blank together preferably automatically forms the finished carton when the flat tube is opened out. As the tube is opened out, the orientation of the second and third tabs changes and the second and third tabs approach each other. For any given angle between the second and third side pieces, the second and third tabs are held at a given orientation. By this means, the tabs involved in the locking mechanism are correctly orientated, as the tube is opened out, in order that the interlocking mechanism operates. In particular, for example, the nose of one of the tabs is guided into the hole of the other tab. If a second locking mechanism is present, this also operates in the same way.

The invention also encompasses half-formed (folded) cartons formed from such carton blanks, as well as the finished cartons.

Accordingly a second aspect of the invention provides a part-formed carton having a substantially flat tube formed from a first side piece, a second side piece, a third side piece and a fourth side piece, the second and third side pieces lying substantially flat and forming one side of the flat tube and the first and fourth side pieces lying substantially flat and forming the other side of the flat tube, and first, second, third and fourth tabs hinged to the first, second, third and fourth side pieces respectively and folded back within the tube, wherein the second and third tabs have an interlocking mechanism adapted to lock the second and third tabs together when the flat tube is opened out to form the finished carton.

In embodiments, the first and fourth tabs have an additional locking mechanism adapted to lock the first and fourth tabs together when the flat tube is opened out to form a carton.

To save material, the sum of the widths of alternate tabs in a direction perpendicular to the hinge line between the tabs and the side pieces associated therewith is advantageously less than the length of the side piece located between the associated side pieces.

Preferably, in order to stabilise the finished carton and ensure the operation of the interlocking mechanism, the second tab includes a portion having a surface glued to the first tab and the fourth tab includes a portion having a surface glued to the third tab. Advantageously, each of the second and fourth tabs includes a score line separating the gluing surface-defining portion from the rest of the tab and the gluing surface-defining portions are folded and glued to the first and third tabs, respectively.

In order to keep the folded carton stable in the folded form the first and third tabs preferably have a corner adapted to engage the second and fourth side pieces, respectively, when the flat tube is opened out.

The tab has to bend slightly in the vicinity of said corners as the carton is erected and this is resisted by the stiffness of the board.

The erection of the carton would still be achieved if the gluing surface-defining portions were not folded but merely scored before gluing the tabs as described above. However, it is preferable to fold the gluing surface-defining portions down, towards the interior of the flat tube. This has two benefits. Firstly, the gluing surface defining portions are unfolded in the erect carton, so that the bottom of the carton when erected has a reasonably even thickness. Secondly, this arrangement correctly locates the engaging corners to retain the partially formed carton in its flat configuration.

According to a third aspect of the invention, there is provided an erect carton comprising a first side piece, a second side piece, a third side piece and a fourth side piece, first, second, third and fourth tabs, one attached to each of the side pieces, forming a bottom for the carton having a hole in its centre, in which the first and second tabs are glued together and the third and fourth tabs are glued together, wherein the second and third tabs are interlocked to hold the carton in its erect form.

In embodiments, the first and fourth tabs are also interlocked to hold the carton in its erect form. Such cartons are stronger than those with only one interlock.

The invention also encompasses cartons and carton blanks forming non-rectangular boxes in the same way, for example hexagonal or octagonal boxes. According to this fourth aspect of the invention, there is provided a carton blank formed from side pieces in a line, each side piece having a tab arranged laterally of it, the carton blank being foldable to form a carton with the said side pieces forming the sides of the carton and the tabs forming the base of the carton, the base having a hole in its centre, wherein at least two of the tabs have a locking mechanism adapted to hold the two tabs together in the carton formed from the blank For a better understanding of the invention specific embodiments will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 shows a plan view of a carton blank according to a first embodiment of the invention.

Figure 2 shows a bottom view of a part-formed, carton formed from the carton blank of Figure 1, Figure 3 shows a perspective view from above of a crash lock carton formed from the carton blank of Figure 1, and Figure 4 shows a carton blank according to a second embodiment of the invention.

The carton blank of Figure 1 comprises a first side piece 1, a second side piece 3, a third side piece 5 and a fourth side piece 7 extending in a line and having score lines 9 between them. Each of the side pieces is rectangular. The first side piece 3 has a cut-away 31. First, second, third and fourth lateral tabs 11,13,15,17 are hinged to the rectangular first, second, third and fourth side pieces, respectively by score lines 9. The tabs are not directly connected to each other, but only to their associated side piece.

An additional tab 19 is provided on the first side piece in line with the side pieces. An interlocking mechanism comprising a nose 21 with an engagement edge 35 is integrally formed with the second tab 13 and a hole 23 adjacent to a locking tab 37 having an engagement edge 38 is formed in the third tab 15.

Portions 25 and 27 having gluing surfaces are provided on the first and third tabs 11,15, respectively. The gluing surface portions 25,27 are approximately triangular, and are separated from the rest of the respective tab by a score line 9. The second and fourth tabs 13, 17 have corners 33 adapted to engage the first and third side pieces 1,5 to hold the partformed carton flat for storage.

In the present embodiment the lengths b of the side pieces are not identical, but are all approximately lOOmm. The width a of each tab is 40mm.

Thus the sum of the widths of alternate tabs is less than the length of the side piece located between the side pieces associated with the alternative tabs.

To form the part-formed carton from the carton blank, the first, second, third and fourth tabs 11, 13, 15, 17 are folded up against the first, second, third and fourth side pieces 1, 3, 5 and 7 respectively. The portions 25 and 27 are then folded down. Glue is applied to the additional tab 19 and to the portions 25,27. The tab 19 is affixed to the fourth side piece 7, to form an open rectangular tube, with the portion 25 on the first tab 11 fixed to the second tab 13 and the portion 27 on the third tab 15 likewise attached to the fourth tab 17. In this arrangement, the partfinished carton blank can easily be folded flat for storage along the score line between the first 1 and second 3 side pieces and the score line between the third and fourth 7 side pieces.

To form the carton from the part-formed carton all that is required is to open out the tube to form a cuboid as shown in Figure 2. The second and fourth tabs 13, 17 have to bend slightly in the region of the corners 33, which engage the first and third side pieces 1, 3 respectively. This creates a slight resistance to opening the tube.

The partially opened tube is shown in Figure 2.

In this bottom view, the first, second, third and fourth tabs 11, 13, 15, 17 can be seen, together with the gluing surface portions 25, 27 glued onto the second and fourth tabs. As the carton is erected, the fourth tab 17 should pass underneath the tab 11; i.e.

in terms of the view from below of Figure 2 the fourth tab 17 should pass in front of the first tab 11. This is achieved by the shapes of the tabs; the first tab 11 is squarer than the fourth tab 17 so that as the carton is erected the first tab 11 passes the imaginary plane 39 bisecting the angle between the first and fourth side pieces 1, 7 before the fourth tab 17 passes said imaginary plane 39. Similarly, the squarer shape of the third tab 15 compared to the nose 21 of the second tab 13 causes it to pass the imaginary plane 41 bisecting the angle between the second and third side pieces 13, 15 before the nose 21. This ensures that the nose passes below the tab 15 (i.e. in front of it in Figure 2) and hence is correctly guided into the hole 23 so that the engagement edge 35 of the nose 21 engages the locking tab 37 as shown in Figure 3. In this position, the finished carton is stable and will retain its form without being held.

The nose 21 on the second tab 13 is arranged to pass through the hole 23 and under a portion of the third tab, as seen by a viewer looking at the bottom of the carton from below. The locking tab 37 is likewise arranged to pass under a portion of the second tab 13.

This forces the nose and tab to be at slightly different angles to the bottom of the erect carton, whereby the engagement edges 35,38 are arranged to be in a flat "X" shape ensuring their engagement one against the other and hence ensuring that the carton is securely locked upright.

In the carton blank, the engagement edge 35 of the nose is substantially parallel to the line of the side pieces, whereas the engagement edge 38 of the locking tab 37 is substantially perpendicular to this line. On folding however, the engagement edges are substantially parallel to each other, apart from their slightly different angles to the base as described in the previous paragraph.

Because the length b of the side pieces is greater than twice the width a of the tabs, the carton when formed has a hole in the centre of its base, which saves material. The interlocking mechanism 21,23 of the invention ensures that the carton remains stable in spite of the narrowing of the tabs.

Figure 4 shows the second embodiment using the same reference numerals for like components. It operates in substantially the same way as the first embodiment.

The second embodiment of Figure 4 has two interlocking mechanisms. Holes 23 are provided in the first and third tabs 1,5 for engagement with noses 21 formed on the fourth and second tabs 7,3 respectively.

The provision of two interlocking mechanisms enhances the stability of the erect carton.

There are also some other minor differences. The locking tab 37 is formed in a triangular shape, which ensures a stronger and less flexible tab than the thin tab of the first embodiment whilst still ensuring that the hole 21 passes through the hole 23 and under the locking tab 37 as the carton is being erected.

The gluing surface portions 25,27 of the second embodiment are attached to the second and fourth tabs 3,7 by a perforated fold line 51. The perforated fold line comprises short slits 53 alternating with cardboard, and is formed during the cutting of the carton blank. For strength the outer portion 55 of the perforated fold line 51 is formed as a score line without perforations.

The carton blank of the second embodiment is erected in the same way as that of the first embodiment. Both noses 21 are automatically guided into the holes 23 to engage with the locking tabs 37 to lock the carton in the erect position.

Claims

1. A carton blank comprising four side pieces in a line, the side pieces each having a length measured along the line, wherein each side piece has a tab arranged laterally of it, the sum of the widths, measured perpendicularly to said line, of alternate tabs being less than the length of the side piece located between the side pieces associated with said alternate tabs, the carton blank is foldable to form a finished carton with the said side pieces forming the sides-of the carton and the said plurality of tabs forming the bottom of the carton, and two of the tabs have an interlocking mechanism adapted to hold the two tabs together in the carton folded from the blank.

2. A carton blank according to claim 1 wherein the interlocking mechanism comprises a nose on one of the tabs and a hole in an adjacent tab, adapted to engage one in the other when the finished carton is formed.

3. A carton blank according to claim 2 in which an end of the tab having the hole is closer than the end of the nose to an imaginary straight line extending between the side pieces to which the tabs having the nose and the hole are attached.

4. A carton blank according to claim 2 or 3 wherein the interlocking mechanism further comprises a locking tab on the tab with the hole extending into or towards the hole for locking the nose in place.

5. A carton blank according to any preceding claim in which portions of the rectangular side pieces are cut away.

6. A carton blank according to any preceding claim further comprising a top piece or pieces for forming a lid or top in the finished carton.

7. A carton blank according to any preceding claim wherein one or more of the tabs includes a portion defining a gluing surface for gluing the tab to an adjacent tab.

8. A carton blank according to claim 7 in which a score line is provided between the portion defining the gluing surface and the rest of the tab.

9. A carton blank according to claim 7 or 8 wherein gluing surface-defining portions are provided on the second and fourth tabs, to glue the first and second tabs and the third and fourth tabs together respectively.

10. A carton blank according to claim 9 in which the interlocking mechanism is provided on the second and third tabs to lock those tabs together.

11. A carton blank according to any preceding claim, comprising noses and holes on alternate tabs to form two interlocking mechanisms.

12. A carton blank substantially as herein described with reference to and as shown in Figures 1 to 3 or 4 of the accompanying drawings.

13. A part-formed carton formed from a carton blank according to any preceding claim.

14. A part-formed carton having a substantially flat tube formed from a first side piece, a second side piece, a third side piece and a fourth side piece, the second and third side pieces lying substantially flat and forming one side of the flat tube and the first and fourth side pieces lying substantially flat and forming the other side of the flat tube, and first, second, third and fourth tabs hinged to the first, second, third and fourth side pieces respectively, wherein the second and third tabs have an interlocking mechanism adapted to lock the second and third tabs together when the flat tube is opened out to form the finished carton.

15. A part-formed carton according to claim 14 further comprising an additional interlocking mechanism on the first and fourth tabs adapted to lock the first and fourth tabs together when the flat tube is opened out to form a carton.

16. A part-formed carton according to claim 14 or 15 in which the sum of the widths of alternate tabs in a direction perpendicular to the hinge line between the tabs and the side pieces associated therewith is less than the length of the side piece located between the associated side pieces.

17 A part-formed carton according to any of claims 14 to 16 in which the first and third tabs have a corner adapted to engage the second and fourth side pieces, respectively, to hold the flat tube substantially flat.

18. A part formed carton according to any of claims 14 to 17, in which the second tab includes a portion having a surface glued to the first tab and the fourth tab includes a portion having a surface glued to the third tab.

19 A part-formed carton according to claim 18 in which the interlocking mechanism comprises a nose in one of the second and third tabs adapted to engage with a hole in the other of the second and third tabs.

20. A part-formed carton according to claim 19 in which the nose is arranged to pass under a portion of the tab having the hole and the locking tab is arranged to pass under a portion of the tab having the nose during erection of the carton, whereby the nose and tab are forced to be at slightly different angles to the bottom of the erected carton ensuring that the nose and tab engage one against the other to lock the carton.

21. A part-formed carton substantially as herein described with reference to and as shown in Figures 1 to 3 or 4 of the accompanying drawings.

22. An erect carton formed from a part-formed carton according to any of claims 13 to 21.

23. An erect carton comprising a first side piece, a second side piece, a third side piece and a fourth side piece, first, second, third and fourth tabs, one attached to each of the side pieces, forming a bottom for the carton having a hole in its centre, in which the first and second tabs are glued together and the third and fourth tabs are glued together, wherein the second and third tabs are interlocked by an interlocking mechanism to hold the carton in its erect form.

24. An erect carton according to claim 23 in which the first and fourth tabs are also interlocked by an interlocking mechanism to hold the carton in its erect form.

25. An erect carton according to claim 23 or 24 in which the or each interlocking mechanism comprises a nose with an engagement edge on one of the interlocked tabs and a locking tab extending towards an engagement hole on the other of the interlocked tabs, the locking tab having a further engagement edge arranged such that the two engagement edges engage one against the other in a substantially, but not exactly parallel arrangement.

26. A carton blank formed from side pieces in a line, each side piece having a tab arranged laterally of it, the carton blank being foldable to form a carton with the said side pieces forming the sides of the carton and the tabs forming the base of the carton, the base having a hole in its centre, wherein at least two of the tabs have an interlocking mechanism adapted to hold the two tabs together in the carton formed from the blank, the interlocking mechanism including a nose on one of the tabs and a hole in an adjacent tab, the nose and hole being adapted to engage one in the other when the finished carton is formed, the interlocking mechanism further including a locking tab on the tab with the hole extending into or towards the hole for locking the nose in place.

26. An erect carton as hereinbefore described with reference to Figs. 1 to 3 or 4 or as shown in Fig. 3 of the accompanying drawings.

27. A carton blank formed from side pieces in a line, each side piece having a tab arranged laterally of it, the carton blank being foldable to form a carton with the said side pieces forming the sides of the carton and the tabs forming the base of the carton, the base having a hole in its centre, wherein at least two of the tabs have a locking mechanism adapted to hold the two tabs together in the carton formed from the blank. Amendments to the claims have been fled as follows Claims 1. A carton blank comprising four side pieces in a line, the side pieces each having a length measured along the line, wherein each side piece has a tab arranged laterally of it, the sum of the widths, measured perpendicularly to said line, of alternate tabs being less than the length of the side piece located between the side pieces associated with said alternate tabs, the carton blank is foldable to form a finished carton with the said side pieces forming the sides of the carton and the said plurality of tabs forming the bottom of the carton, and the carton blank further comprises an interlocking mechanism including a nose on one of the tabs and a hole in an adjacent tab, the nose and hole being adapted to engage one in the other when the finished carton is formed, the interlocking mechanism further including a locking tab on the tab with the hole extending into or towards the hole for locking the nose in place.

2. A carton blank according to claim 1 wherein the nose has an engagement edge substantially parallel to the line of the side pieces and the locking tab has an engagement edge substantially perpendicular to this line arranged so that the engagement edges engage one against the. other in the finished carton.

4. A carton blank according to any preceding claim in which portions of the rectangular side pieces are cut away.

5. A carton blank according to any preceding claim further comprising a top piece or pieces for forming a lid or top in the finished carton.

6. A carton blank according to any preceding claim wherein one or more of the tabs includes a portion defining a gluing surface for gluing the tab to an adjacent tab.

7. A carton blank according to claim 7 in which a score line is provided between the portion defining the gluing surface and the rest of the tab.

8. A carton blank according to claim 7 or 8 wherein gluing surface-defining portions are provided on the second and fourth tabs, to glue the first and second tabs and the third and fourth tabs together respectively.

9. A carton blank according to claim 9 in which the interlocking mechanism is provided on the second and third tabs to lock those tabs together.

10. A carton blank according to any preceding claim, comprising noses and holes on alternate tabs to form two interlocking mechanisms.

11. A carton blank substantially as herein described with reference to and as shown in Figures 1 to 3 or 4 of the accompanying drawings.

12. A part-formed carton formed from a carton blank according to any preceding claim.

13. A part-formed carton having a substantially flat tube formed from a first side piece, a second side piece, a third side piece and a fourth side piece, the second and third side pieces lying substantially flat and forming one side of the flat tube and the first and fourth side pieces lying substantially flat and forming the other side of the flat tube, and first, second, third and fourth tabs hinged to the first, second, third and fourth side pieces respectively, wherein the second and third tabs have an interlocking mechanism adapted to lock the second and third tabs together when the flat tube is opened out to form the finished carton, the interlocking mechanism including a nose on one of the tabs and a hole in an adjacent tab, the nose and hole being adapted to engage one in the other when the finished carton is formed, the interlocking mechanism further including a locking tab on the tab with the hole extending into or towards the hole for locking the nose in place.

14. A part-formed carton according to claim 14 further comprising an additional interlocking mechanism on the first and fourth tabs adapted to lock the first and fourth tabs together when the flat tube is opened out to form a carton.

15. A part-formed carton according to claim 14 or 15 in which the sum of the widths of alternate tabs in a direction perpendicular to the hinge line between the tabs and the side pieces associated therewith is less than the length of the side piece located between the associated side pieces.

16. A part-formed carton according to any of claims 14 to 16 in which the first and third tabs have a corner adapted to engage the second and fourth side pieces1 respectively, to hold the flat tube substantially flat.

17. A part formed carton according to any of claims 14 to 17, in which the second tab includes a portion having a surface glued to the first tab and the fourth tab includes a portion having a surface glued to the third tab.

18. A part-formed carton according to claim 18 in which the interlocking mechanism comprises a nose in one of the second and third tabs adapted to engage with a hole in the other of the second and third tabs.

19. A part-formed carton according to claim 19 in which the nose is arranged to pass under a portion of the tab having the hole and the locking tab is arranged to pass under a portion of the tab having the nose during erection of the carton, whereby the nose and tab are forced to be at slightly different angles to the bottom of the erected carton ensuring that the nose and tab engage one against the other to lock the carton.

20. A part-formed carton substantially as herein described with reference to and as shown in Figures 1 to 3 or 4 of the accompanying drawings.

21. An erect carton formed from a part-formed carton according to any of claims 14 to 21.

22. An erect carton comprising a first side piece, a second side piece, a third side piece and a fourth side piece, first, second, third and fourth tabs, one attached to each of the side pieces, forming a bottom for the carton having a hole in its centre, in which the first and second tabs are glued together and the third and fourth tabs are glued together, wherein the second and third tabs are interlocked by an interlocking mechanism to hold the carton in its erect form, the interlocking mechanism including a nose on one of the tabs and a hole in an adjacent tab, the nose and hole engaging one in the other, the interlocking mechanism further including a locking tab on the tab with the hole extending into or towards the hole, locking the nose in place.

23. An erect carton according to claim 23 in which the first and fourth tabs are also interlocked by an interlocking mechanism to hold the carton in its erect form.

24. An erect carton according to claim 23 or 24 in which the or each interlocking mechanism comprises a nose with an engagement edge on one of the interlocked tabs and a locking tab extending towards an engagement hole in the other of the interlocked tabs, the locking tab having a further engagement edge arranged such that the two engagement edges engage one against the other in a substantially, but not exactly parallel arrangement.

25. An erect carton as hereinbefore described with reference to Figs. 1 to 3 or 4 or as shown in Fig. 3 of the accompanying drawings.