CONTAINER WITH LOCKING TAB CLOSURE

Abstract

Herein is provided a container including a plurality of sidewalls (3, 7, 9) connected to one another along foldlines, and a base. The base includes first, second, third and fourth base flaps (11, 13, 15, 17) connected along respective foldlines to respective sidewalls. The second and third base flaps (13, 15) are folded over the first base flap (11) and the fourth base flap (17) is folded over the second and third base flaps (13, 15). The fourth base flap (17) includes a base panel portion which forms part of the exterior of the base and a locking tab portion connected to a distal end of the base panel portion. The locking tab portion is inserted into the interior of the container through a slot defined by the first, second and third base flaps (11, 13, 15) to retain the base in a closed configuration. A cutline is provided extending inwardly from the side edge of the fourth base flap (17) on each side of the fourth base flap (17) at a transition between the base panel portion and the locking tab portion.

Claims

1. A container comprising; a plurality of sidewalls connected to one another along foldlines; and a base, wherein the base comprises; a first base flap connected along a foldline to a first one of the sidewalls; second and third opposed base flaps connected along respective foldlines to respective ones of the sidewalls adjacent the first sidewall on either side thereof, wherein the second and third base flaps are folded over the first base flap; and a fourth base flap connected along a foldline to a sidewall opposite the first sidewall, wherein the fourth base flap is folded over the second and third base flaps; wherein the fourth base flap comprises a base panel portion which forms part of the exterior of the base and a locking tab portion connected to a distal end of the base panel portion, wherein the locking tab portion of the fourth base flap is inserted into the interior of the container through a slot defined by the first, second and third base flaps to retain the base in a closed configuration; and wherein a cutline is provided extending inwardly from the side edge of the fourth base flap on each side of the fourth base flap at a transition between the base panel portion and the locking tab portion of the fourth base flap.

2. The container of claim 1 wherein each cutline receives an edge of a respective one of the second and third base flaps to inhibit movement of the locking tab portion out of the slot.

3. The container of any preceding claim wherein each cutline extends less than 30%, or less than 25%, or less than 20% of a distance toward an opposite side edge of the fourth base flap.

4. The container of any preceding claim each cutline extends at least 5%, or at least 10% or at least 15% of a distance toward an opposite side edge of the fourth base flap.

5. The container of any preceding claim wherein the cutlines do not converge with one another.

6. The container of any one of claims 1 to 5 wherein the cutlines converge with one another.

7. The container of claim 6 wherein the cutlines are inclined toward the foldline connecting the fourth base flap to the sidewall of the container to which the fourth base flap is connected.

8. The container of any preceding claim wherein the second and third base flaps each comprise proximal and distal portions, and the slot is defined by an edge region of the distal portion of each one of the second and third base flaps and an edge defined by the first base flap.

9. The container of claim 8 wherein the first base flap comprises a recess formed in a distal end thereof, wherein a portion of a distal edge of the first base flap defining a proximal end of the recess provides the edge defined by the first base flap which cooperates with edge regions of the distal portions of the second and third base flaps to define the slot through which the locking tab of the fourth base flap is inserted.

10. The container of claim 9 wherein the first base flap comprises distal end portions on either side of the recess, wherein an inner edge region of each distal end portion of the first base flap defines a hook.

11. The container of any preceding claim wherein each cutline extends inwardly from a side edge of the fourth base flap in proximity to a point at which a direction of the side edge of the fourth base flap changes direction as the base panel portion of the fourth base flap transitions into the locking tab portion.

12. The container of claim 11 wherein each cutline extends inwardly from the side edge of the fourth base flap distal to a point at which a direction of the side edge of the fourth base flap changes direction as the base panel portion of the fourth base flap transitions into the locking tab portion.

13. The container of any preceding claim wherein the base panel portion of the fourth base flap is generally trapezoidal in shape.

14. The container of any preceding claim wherein the second and third base flaps each comprise proximal and distal portions, and the slot is defined by an edge of the distal portion of each one of the second and third base flaps and an edge defined by the first base flap and/or by a surface of the distal portion of each one of the second and third base flaps and an edge defined by the first base flap.

15. The container of any preceding claim wherein the second and third base flaps each comprise proximal and distal portions, and the distal portions of each of the second and third base flaps define hooks, wherein the hooks are tucked behind a slot defining edge defined by the first base flap.

16. The container of claim 15 wherein the slot is defined by the edge defined by the first base flap and a surface of the distal portion of each of the second and third base flaps in the region of the hook.

17. The container of any preceding claim wherein the second and third base flaps each comprise a proximal and a distal portion, wherein a side edge of the flap changes direction at a transition between the proximal and distal portions thereof, and wherein each cutline receives an edge of a respective one of the second and third base flaps at the transition between the proximal and distal portions of the second or third base flap to inhibit movement of the locking tab portion out of the slot.

18. The container of any preceding claim wherein a respective reinforcement flap is provided underlying at least one of the first and fourth base flaps.

19. The container of claim 18 wherein the or each reinforcement flap is connected to a respective sidewall of an inner shell of the container along a respective foldline.

20. The container of claim 18 or claim 19 wherein each reinforcement base flap is in face to face contact with, and unsecured to, the inner surface of its respective base flap.

21. The container of any preceding claim wherein the container comprises inner and outer shells, wherein the outer shell comprises the sidewalls to which the first, second, third and fourth base flaps are connected.

22. The container of any preceding claim, wherein the container is a single piece container.

23. A blank erectable to provide a container in accordance with any one of the preceding claims.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0088] Some preferred embodiments of the invention will now be described by way of example only and with reference to the followings drawings, of which;

[0089] FIG. 1 shows a blank in the flat for forming a container in accordance with a first embodiment of the present invention;

[0090] FIG. 2 illustrates the configuration of the base flaps used in the blank of FIG. 1 in more detail;

[0091] FIG. 3 illustrates an alternative configuration of base flaps which may be used in embodiments of the invention;

[0092] FIGS. 4A-G illustrate one method of erecting the blank of FIG. 1;

[0093] and FIG. 5 illustrates the interior of the base of the container of FIG. 4G through the open lid;

[0094] FIG. 6 illustrates an alternative embodiment including reinforcement flaps;

[0095] and FIG. 7 illustrates yet another possible flap configuration.

DETAILED DESCRIPTION

[0096] With reference to FIG. 1, a blank for providing a container in accordance with a first embodiment of the invention will now be described.

[0097] FIG. 1 shows the blank in the flat from above, from the side which will provide the exterior of the erected container.

[0098] The blank 1 includes a first sidewall 3, a second sidewall 5, a third sidewall 7, and a fourth sidewall 9. The first and second sidewalls are connected to one another along a foldline 23, and the first and third sidewalls are connected to one another along a foldline 25. The second and fourth sidewalls are connected to one another along a foldline 27. A glue flap 10 is connected to the fourth sidewall 9 along a foldline 29.

[0099] The components of the base construction of the container will now be described.

[0100] A first base flap 11 is connected to the end of the first sidewall along a foldline 12. A second base flap 13 is connected to the end of the second sidewall 5 along a foldline 14. A third base flap 15 is connected to the end of the third sidewall 7 along a foldline 16. A fourth base flap is connected to the end of the fourth sidewall 9 along a foldline 18.

[0101] The first base flap has a recess 22 at its distal end.

[0102] The fourth base flap 17 has a base panel portion 19 which lies to the exterior of the container when erected and a locking tab portion 21 at the distal end of the base panel portion 19. The locking tab portion 21 lies within the container when erected.

[0103] The approximate extent of the base panel portion 19 is shown in hatched lines for ease of illustration in FIG. 1. The exact extent of the portion of the fourth base flap which will form part of the exterior of the base in the erected container, and thus the extent of the base panel portion 19, will depend upon the nature of the materials used e.g. the basis weight thereof, and the manner of erection of the blank. In the embodiment illustrated, the locking tab portion extends distally from approximately the level of the cutlines 26, 28, which will be located on the exterior of the container. It will be appreciated that there is no foldline or other feature extending between the edges of the fourth base flap to delineate the locking tab portion and base panel portions thereof. It has been found that it is advantageous not to include a foldline or similar to separate the locking tab portion from the base panel portion as such a foldline may undesirably interfere with the ability of the locking tab portion to be fully inserted through a slot defined by the first, second and third base flaps as described herein when erecting the container. Consequently, the provision of such a foldline or similar may disadvantageously increase the tendency of the locking tab portion to move out of the slot.

[0104] A pair of cutlines 26, 28 are provided, one on either side of the fourth base flap 17, extending inward from the side edge of the base flap. In the illustrated embodiment the cutlines are straight lines extending parallel to the foldline 18 connecting the fourth base flap to the fourth sidewall, and are located at the same distance as each other from the foldline i.e. so as to be at the same height within the fourth base panel 17.

[0105] A set of flaps 300 are provided at the opposite end of the sidewalls to the base, which may be used to provide a lid for the container. These flaps are of conventional construction and will not be described further.

[0106] The construction of the base flaps will now be described in more detail by reference to FIG. 2.

[0107] The first base flap 11 has a proximal portion 35 and a pair of distal end portions 37, 39 on either side of the recess 22. The recess 22 has a proximal end edge 41 and side edges 43, 45, which also provide inner edges of the distal end portions 37, 39. The distal end portions 37, 39 have outer side edges 47, 49 and end edges 55, 57. The proximal portion has side edges 51, 53. Again, the distal end portions are shown as hatched regions merely for the purposes of illustration, and do not imply that any detectable discontinuity or other feature separates these regions from the proximal portion of the flap.

[0108] In the exemplary first base flap shape shown, the side edges 51, 53 of the proximal portion 35 are parallel to one another, and the outer side edges 47, 49 of the distal end portions 37, 39 converge with one another toward the distal end of the flap, such that the distal portions of the first base flap define hooks 46, 48. The inner edges 41, 43 of the distal end portions 37, 39 and hence the side edges of the recess 22 converge with one another toward the distal end of the flap 11. Of course, other shapes may be used. For example, the inner and/or outer side edges of the distal end portions may extend parallel to one another. The configuration and extent of the recess may be different from that shown.

[0109] The second and third base flaps 13, 15 are mirror images of one another in the embodiment illustrated. The features of the flaps will be described by reference to the second base flap 13. The corresponding parts of the third base flap 15 will be marked annotated by a “′” sign.

[0110] The second base flap 13 has a proximal portion 61 and a distal portion 63.

[0111] The distal portion is shown as a hatched region merely for the purposes of illustration, and this does not imply that any detectable discontinuity or other feature separates these regions from the proximal portion of the flap. The second base flap has a distal end edge 65 and a side edge 67 which provides a side edge of both the proximal and distal portions on the side closest to the fourth base flap 17. The distal portion 65 of the second base flap has a side edge 69 on the side closer to the first base panel 11. On the same side of the second base flap, the proximal portion 61 of the second base flap has a first portion 70 joined to the side edge 69 of the distal portion 65, and a second portion 71 joining the first portion 70 to the foldline 14 connecting the second base flap to the second sidewall.

[0112] An angle α is defined between the end edge 65 and the side edge 69 of the distal portion 63. The angle is an acute angle. In this way, hooks 50, 50′ are defined by the second and third base flaps. An angle β is defined between the side edge 69 of the distal portion 63 of the flap and the first portion 70 of the side edge of the proximal portion 61. The side edge 69 of the distal portion 63 is a straight edge. The side edge of the proximal portion 61 extends straight through the first portion 70 thereof until closer to the foldline 14, before changing to approach the foldline 14 more steeply in the second portion 71. The second portion 71 of the side edge meets the foldline 14 so as to be spaced from the edge of the first end flap.

[0113] Of course, different shapes may be used, and the second base flap may extend to the edge of the adjacent first base flap i.e. at the corner between the first and second sidewalls 3, 5 in the erected container. The angles α, β may be varied. The angle β at which these side edge portions meet may be controlled to aid in maintaining the locking tab portion 19 in its tucked in position, and to enhance strength of the base. The angle α may be 90 degrees. However, an acute angle may create a hook and help to enhance retention of the locking tab portion 19 within the slot defined by the distal edges 69, 69′ of the second and third base flap portions in use. The side edge of the proximal portion need not have distinct first and second portions as illustrated. For example, the first portion 70 may continue along a straight path until it meets the foldline 14 e.g. adjacent the first flap.

[0114] The features of the fourth base flap 17 have been previously described and are indicated again in FIG. 2. In FIG. 2 a dotted line is used to indicate the approximate extent of the base panel portion 19 of the fourth base flap 17, although this is for illustration only as described above. The side edges of the flap 17 converge with one another along first portions 80, 82. The side edges then change direction becoming briefly parallel as the base panel portion 19 transitions into the locking tab portion 21, which has curved side edges provided by the side edge portions 83, 85. The change in shape between the main body of the base panel portion 19 and the locking tab portion 21, resulting in the side edges of the flap converging less steeply in the locking tab portion, ensures that the amount of material present in the locking tab portion which is located to the interior of the container when the base is closed may be maximized. The locking tab portion 21 has a straight end edge 87 extending parallel to the foldline 18.

[0115] It will be seen that the base panel portion 19 is generally trapezoidal. The region in which the base panel portion 19 starts to transition into the locking tab portion 21 is not taken into account when considering the general shape of the base panel portion 19, which is defined by the shape of the main body of the base panel portion.

[0116] The cutlines 26, 28 extend inward from the side edges of the fourth base flap at the transition between the base panel portion 19 and the locking tab portion 21. The cutlines are therefore provided at the base of the locking tab portion. The cutlines may be located at any position along the height of the fourth base flap in the region of the transition between the base flap portion and locking tab portion which enables them to cooperate with the edges of the second and third base flaps as described herein.

[0117] It will also be understood that the shape of the various base flaps may differ from those shown in the embodiment of FIGS. 1 and 2. For example, the shape of the recess in the distal end of the first base flap 11 may differ. The inner and/or outer edges of the distal portions of the first base flap need not converge with one another to define hooks. The angle made by the side edge 69, 69′ of the distal portion of the second and third base flaps may differ from that illustrated, to result in no hooks being defined, or hooks having ends with differing levels of sharpness, as may the angle defined where the side edge of the distal portion meets the side edge of the proximal portion. The side edge of the proximal portion need not be formed from two distinct portions as shown. Finally the shape of the locking tab and/or base panel portion of the fourth base flap may differ from that shown. FIG. 7 illustrates an alternative flap configuration in which the second and third base flaps define sharper hooks.

[0118] The configuration of the cutlines may differ from that shown. A detail of an alternative cutline configuration accordance with a further embodiment of the invention will now be described by reference to FIG. 3. The container of this embodiment is identical to that of the earlier embodiment, other than in the orientation of the cutlines (although may incorporate any of the modifications described in relation to the earlier embodiment).

[0119] The first, second third and fourth base flaps 111, 113, 115, 117 in this embodiment are of identical construction to those of the earlier embodiment described by reference to FIG. 2. However, in this embodiment, rather than extending parallel to the fold line 118 connecting the fourth base flap 117 to the fourth sidewall, the cutlines 126, 128 converge with one another, being inclined toward the base of the fourth base flap 117 i.e. toward the fold line 118.

[0120] It has been found that the configuration of the cutlines shown in either of the FIG. 2 or 3 embodiments may be advantageous in supporting the function of the cutlines in inhibiting movement of the locking tab portion out of the slot after initial closing of the base.

[0121] One embodiment of erecting the blank of the embodiment of FIGS. 1 and 2 to form a container will now be described by reference to FIGS. 4A-G. Erection of the blank of FIG. 3 would proceed in the same manner.

[0122] With the blank located with the opposite surface to that shown in FIG. 1 uppermost i.e. with the surface that will form the interior of the container uppermost, the blank is folded about the third foldline 27 to result in the fourth sidewall 9 overlying the second sidewall 5. Glue is applied to the exterior surface of the glue flap 10 i.e. the surface uppermost in FIG. 1, and the blank folded about the second foldline 25 to result in the third sidewall 7 overlying the first sidewall 3 and with the free edge of the third sidewall 7 overlying the glue flap 10 to adhere the third sidewall 7 thereto.

[0123] The result of this initial folding and gluing stage is shown in FIG. 4A. The folded and glued blank is in a flat configuration.

[0124] The fourth, third and second sidewalls 9, 7, 5 are then rotated relative to the first sidewall 3 through the position shown in FIG. 4B to reach the position shown in FIG. 4C, in which the container is in an erect configuration, but with the lid and base open. This may be achieved e.g. by applying suction to the upper surface of the folded blank shown in FIG. 4A, or by urging the sides of the folded blank inwardly, or in any suitable manner.

[0125] The steps involved in closing of the base will now be described.

[0126] The first base flap 11 is rotated about the foldline 12 in the direction shown in FIG. 4C to the position shown in FIG. 4D, lying perpendicular to the first sidewall 3.

[0127] The second and third base flaps 13, 15 are then rotated about the respective foldlines 14, 16 connecting them to the second and third sidewalls in the direction of the arrows shown in FIG. 4D to the position shown in FIG. 4E in which each base flap is perpendicular to the sidewall to which it is connected. The second and third base flaps 13, 15 are thus folded over the first base flap 11.

[0128] The fourth base flap 17 is then rotated about the foldline 18 connecting it to the fourth sidewall 9 in the direction of the arrow shown in FIG. 4E to the position shown in FIG. 4F. Thus the fourth base flap 17 is folded over the second and third base flaps 13, 15 to a position in which it lies perpendicular to the sidewall 9 to which it is connected.

[0129] The distal end of the fourth base flap 17 is then inserted into the interior of the container. As the fourth base flap is inserted into the interior of the container, it causes the hooks 50, 50′ associated with the distal portions of the second and third base flaps 13, 15 to be tucked behind the edge 41 of the recess 22. In this way, a closed base is obtained as shown in FIG. 4G. The base panel portion 19 of the fourth base flap 17 forms part of the exterior of the base. The locking tab portion 21 extends through a slot defined by the end regions of the distal portions 63, 63′ of the second and third base flaps 13, 15 and the proximal edge 41 of the recess 22 of the first base flap 11. In the embodiments illustrated, in which the distal portions of the second and third base flaps define hooks, a surface of the respective base flaps in the region of the hooks defines the slot with the edge 41 defined by the first base flap. In the embodiment illustrated, an outer surface of the base of the hooks defines the slot with the edge 41. However, in other embodiments, e.g. where no hooks are provided, the side edges 69, 69′ of the distal portions of the second and third base flaps may define the slot with the edge 41. Where hooks are provided, the surface of the distal portions of the second and third base flaps which define the slot with the first base flap may be a region away from the base, or even proximal to the base of the hooks.

[0130] The cutlines are not visible in FIG. 4G, being disposed in the region where the locking tab portion 21 bends around to enter the interior of the container, where they may cooperate with the side edges of the second and third base flaps 13, 15.

[0131] In the embodiment illustrated, it will be seen that the slot is present in the closed base, but not prior to the final stage of tucking the locking tab portion of the fourth base flap into the interior of the container.

[0132] Modifications may be made to the method described in relation to FIGS. 4A-G, which illustrates only one exemplary method for erecting the container. For example, rather than tucking the hooks associated with the second and third base flaps behind the edge 41 as part of the step of inserting the locking tab portion into the interior of the container, this may be carried out as a separate, preceding step.

[0133] The resulting closed base has the appearance of the reverse of an envelope, and may be referred to as an “envelope” base. It will be seen that parts of the proximal portions 61, 61′ of the second and third base flaps 13, 15 and the proximal portion 35 of the first base flap 11 also form part of the exterior of the base.

[0134] A product may then be loaded into the container so as to be supported by the closed base, and the flaps 300 used to provide a closed lid.

[0135] The base of the container as shown in FIG. 4G when viewed from the interior is shown in FIG. 5. Here it may be seen how, viewed from the interior, the locking tab portion 21 overlies a part of the proximal portion 35 of the first base flap 11. The hooks 50, 50′ of the distal portions 63, 63′ of the second and third base flaps 13, 15 may also be seen. A base portion of the locking tab portion 21 is sandwiches between these hooks and the first base flap. The extent of this sandwiching effect depend upon the sharpness of the ends of the hooks, and the extent to which the hooks extend beyond the edge 41. The distal portions 37, 39 of the first base flap 11 overlie the distal portions 63, 63′ of the second and third base flaps. The hooks defined by the distal portions 37, 39 help to ensure that the portions remain in position even when an outwardly directed force is exerted on the interior of the base in use, when a product is located therein. The use of hooks on the second, third and first base flaps thus assists in maintain the base in a closed state even when outward forces are exerted on the interior thereof in use, further improving the strength of the base. However, these are only preferred features.

[0136] The cutlines 26, 28 have been found to help prevent the locking tab portion 21 of the fourth base flap 17 from coming out of the slot when a force is applied to the interior of the base urging it outwardly (i.e. as would be the case if a product is located in the container), and hence to improve the strength of the base. The main cause of failure of this type of base would be the locking tab coming out of the slot, as this is what maintains the base in its closed configuration. It has been found that the cutlines may catch on the side edges of the second and third base flaps 13, 15 closest to the first base flap 11 in the region of the transition between the proximal and distal portions 61, 63, 61′, 63′ of the flaps 13, 15. This is the region where the side edge 69, 69′ of the distal portion 63, 63′ meets the first portion 70, 70′ of the side edge of the proximal portion of the flap. The side edges of the second and third base flaps are received in the cutlines preventing the locking tab portion 19 from moving out of the slot.

[0137] The cutlines may be located at various points around the transition between the base panel portion 19 and locking tab portion 21 of the fourth base flap 17 to enable them to function in this way. However, it has been found that it is advantageous if the cutlines are located so as to be in the region where the locking tab portion bends around to enter the base i.e. between the inner and outer walls of the base, or just on the interior of the base of the container so as to enable them to most reliably receive the edges of the second and third base flaps and prevent movement of the locking tab portion out of the slot, at least if a force applied to the interior of the base by a product located within the container causes the locking tab portion to tend to move out of the slot. In the embodiment illustrated, the cutlines are located just distal to the point at which their respective side edge starts to change direction as the base panel portion 19 transitions into the locking tab portion 21.

[0138] FIG. 6 illustrates a further embodiment of the invention, in which a container 200 has first, second, third and fourth base flaps of similar construction to the embodiment of FIG. 3. The fourth base flap has cutlines 228, 226. However, in this embodiment, a first reinforcement flap 218 is disposed within the first base flap 211, and a second reinforcing base 220 is located within the fourth base flap 217. The reinforcement flaps may be associated with the ends of sidewalls of an inner shell of the container, or may be provided in any other suitable manner. Closure of the base of this further embodiment proceeds in the same manner described in relation to FIGS. 4C-G. In this case, when the first base flap 211 is folded up the first reinforcement flap 220 is folded up within it to underlie the first base flap 211. When the locking tab portion of the fourth base flap 217 is pushed into the interior of the container, it causes the second reinforcement flap 220 to move with it such that a distal end of the second reinforcement flap will underlie the locking tab portion, providing a reinforcement to the locking tab portion. The distal end of the second reinforcement flap will thus extend through the slot, underlying the locking tab portion.

[0139] In this embodiment, the first and second reinforcement flaps have the same shape as their corresponding base flaps, but have an outer contour lying within the contour of the base flap. This may provide some tolerance to ensure the reinforcement flaps are not visible from the exterior of the closed base. Thus, the second reinforcement flap defines correspondingly shaped portions for reinforcing the base panel and locking tab portions of the fourth base flap. However, in other embodiments the reinforcement flaps may have a different shape to their base flaps, provided they extend over a sufficient area to reinforce the base flaps. For example, the first reinforcing base flap may extend over only the proximal portion of the first base flap 218. These embodiments may further enhance the strength of the base, providing additional benefits. This is synergistic with the strength benefits provided by the use of the cutlines. The use of reinforcement flaps may increase strength in those areas of the base where particularly critical, but without the need to e.g. laminate layers together to provide a double thickness over the entire container, which may disadvantageously add processing complexity. The second reinforcement flap need not include cutlines, although in some embodiments, it may include cutlines at a corresponding position to the fourth base flap. In these embodiments, the reinforcement flaps are unsecured to their respective base flaps. However, in other embodiments it is envisaged that some attachment may be used, although advantageously an unsecured arrangement is used, to provide reinforcement in key areas of the base, but without the added complication of bonding the flaps together.

[0140] It is envisaged that only one of the first and second reinforcement flaps may be used, or additional reinforcement flaps may be associated with the second and third base flaps.

[0141] It will be appreciated that the present invention may be used in conjunction with a container having an inner shell regardless of whether reinforcement flaps are provided. The sidewalls associated with the first, second, third and fourth base flaps will then form part of the outer shell. An inner shell may be of any suitable construction, and may be provided as part of the same blank which provides an outer shell. An inner shell may help to support a product within the container and/or reinforce the sidewalls of the outer shell of the container. For example, an inner shell may reinforce the sidewalls of the outer shell of the container to provide additional strength. This may provide a particularly strong container in conjunction with the base structure described herein. An inner shell may be of any suitable construction e.g. in terms of number of sidewalls, shape of sidewalls, extent of sidewalls relative to the sidewalls of the outer shell, position of sidewalls relative to sidewalls of outer shell etc.

[0142] FIG. 7 illustrates yet further examples of shapes which may be used for the first, second, third and fourth base flaps in any of the embodiments of the invention, whether or not reinforcement flaps are used. This figure illustrates some exemplary flap shapes, which happen to be shown in a different order to the blank of FIGS. 1 and 2. The flap shapes are respectively for the first flap (300), second and third flaps (308, 304) and fourth base flap (306). These illustrate an embodiment in which the distal portions of the second and third base flaps define sharper hooks which may tuck behind the edge defined by the recess in the first base flap. In these embodiments, the slot may be defined by a surface of the distal portions of the second and third base flaps in the region of the base of the hooks.

[0143] A container in accordance with the embodiment of FIGS. 1 and 2 (invention) was tested to determine the weight of a bottle which could be held before the base failed as a result of the locking tab portion of the fourth base flap coming out of the slot. The container was compared to a container of identical construction, but without the cutlines (comparative). Tables 1 and 2 show the result of testing the comparative and inventive arrangements respectively. In each case, an average of 10 replicates was taken.

[0144] Table 3 summarizes the results obtained. It may be seen that considerable improvements in the minimum, maximum and average load at break was provided by the invention in comparison to the comparative example.

[0145] Base factor is a safety factor indicative of a force required to push a bottle through the base. For example, a 6 kgf required to push a 1.5 kg bottle through the base will provide a factor of safety of 4.

Comparative

[0146]

TABLE-US-00001 TABLE 1 Load at Load Filled Maximum at Bottle Load Break Weight Base (kgf) (kgf) (kg) Factor 16.01 12.80 1.15 14.98 15.70 12.56 1.15 14.71 15.52 12.42 1.15 14.56 15.78 12.62 1.15 14.78 15.01 12.01 1.15 14.11 14.98 11.98 1.15 14.08 15.21 12.17 1.15 14.29 16.03 12.82 1.15 15.00 14.97 11.98 1.15 14.07 15.89 12.71 1.15 14.88 15.51 12.41 1.15 14.55

Invention

[0147]

TABLE-US-00002 TABLE 2 Load at Load Filled Maximum at Bottle Load Break Weight Base (kgf) (kgf) (kg) Factor 30.13 24.11 1.15 27.32 24.02 19.22 1.15 21.98 26.47 21.18 1.15 24.12 30.24 24.20 1.15 27.41 23.28 18.63 1.15 21.33 26.83 21.46 1.15 24.43

TABLE-US-00003 TABLE 3 Invention Comparative Load at Load at break Summary break (kgf) (kgf) Improvement Min 14.07 21.33 52% Average 14.55 24.43 68% Max 15.00 27.41 83%

[0148] While attachments have been described as adhesive attachments herein, it will be appreciated that any suitable bonding technology e.g. heat sealing may be used, or combinations of such technologies.

[0149] While the slot defining edge of the first base flap has been illustrated as a proximal edge of a recess in the distal edge thereof, the slot defining edge may instead be provided by an edge e.g. proximal edge of an opening in the flap.

[0150] All of the assembly steps described by reference to FIGS. 4A-G, including all gluing and folding steps, may be performed in a fully automated manner by a machine.

[0151] It will be understood that the above description is of a number of exemplary embodiments only and that modifications may be made to the embodiments without departing from the scope of the invention.