This invention relates to sleeve- for wrapping a plurality of parallelepiped containers ...ich having a pair of protruding angled base tucks. Such containers include those produced under the registered trade mark "Tetra Brik" . According to a first aspect of the present invention there is provided an open-ended paperboard sleeve for wrapping a plurality of parallelepiped containers, which containers each have a base panel incorporating a pair of protruding angled base tucks, said sleeve comprising a top portion, two side portions and a base portion and incorporating flap means which in use are folded so as to lie generally between the base portion and the base panel of at least one of said containers so as to cooperate with one or more of said base tucks of at least one container to prevent withdrawal of the containers through the open ends of the sleeve.

Preferably the flap means comprises one or more flaps each of which is formed from either a side portion or the base portion or a combination of both in the region of the junction between the base portion and the side portion and also when the flap spans the junction of the base portion and the side portion, the hinged connection between the side portion and the base portion does not continue across the flap which remains unfolded.

In preferred arrangements each flap has a 45° edge relative to the lengthwise axis of the sleeve for engagement with a 45° angled edge of its associated base tuck.

With a further embodiment the hinge line about which each flap is rotated into its in use position is generally parallel to the hinged connection between the base portion and the two side portions. Conveniently the base portion incorporates two bottom panels hingedly connected to respective side portions,

which panels are joined together to close the sleeve and preferably the two bottom panels are formed with interlocking formations to join them together.

According to a second aspect of the present invention there is provided a blank for producing the above described sleeves.

An embodiment of the present invention will now be described in more detail. The description makes reference to the accompanying diagrammatic drawings in which Figure 1 is a view of a blank for producing the sleeve according to the present invention,

Figure 2 is a perspective view from below of the sleeve during assembly around a plurality of containers, Figure 3 is a perspective view from above of the assembled sleeve, and

Figure 4 is a perspective view from below of another sleeve during assembly.

In the figures there is shown a paperboard blank 10 for making a sleeve for wrapping a plurality of brick-shaped parallelepiped containers 11 which may contain liquids such as fruit juice. Such containers are well known and one particular container 11 is sold under the registered trade mark "Tetra-Brik" . On the base of such a container 11 the corners are tucked back under the base at 13 about a hinge line 12 and then secured to the base. These tucks 13 protrude slightly from the remaining area of the base and have edges 14 which are angled at about 45° relative to the axes of the base.

In a typical multipack 15, four containers 11 are arranged in a rectangular 2 X 2 array as shown most clearly in figure 2. The blank 10 for the sleeve has a top portion 16 for lying against the top panels of the containers 11, two side portions 17, 18 hingedly connected at 19, 20 to opposite side edges of

the top portion 16 an two bottom panels 21, 22 hingedly connected at 23, 24 to the bottom edges of the side panels. The bottom panel 21 is formed with hinged locking panels 25, 26 each of which has a primary locking tab 27 and a secondary locking tab 28 whilst the bottom panel 22 is formed with a pair of cutouts 28 defining locking shoulders 29 and with a pair of cut lines 30 incorporating hinge lines 31.

The blank 10 is also formed with flaps 32 in the region of the hinge lines 23, 24 which are interrupted by the flaps 32. Each flap 32 spans the associated hinge line 23, 24 and the flaps 32 are provided either side of the central transverse axis of the sleeve. Each flap is formed with an inward facing edge 33 at 45° to the central transverse axis. To apply the blank 10 to the containers 11 the top portion 16 is arranged over the tops of the containers 11 and the side portions 17, 18 are hinged towards the sides of the array of containers 11, but the bottom panels 21, 22 are bent outwards during this procedure. This ensures that the flaps 32 remain aligned with the bottom panels 21, 22 so that when the side portions 17, 18 engage the sides of the array of containers 11 the flaps are not trapped by the side portions 17, 18. The bottom panels 21, 22 are then hinged under the bases of the containers such that the flaps 32 are trapped between the containers 11 and the bottom panels 21, 22. In these positions the flaps lie alongside the angled edges 14 of the base tucks 13 of the containers 11 and against the non protruding portions of the bases of the containers 11. The primary and secondary locking tabs 27, 28 are then engaged with the locking shoulders 29 and cut lines 30 in the known manner thereby securing the blank 10 into its sleeve formation around the array of containers 11.

The sleeve of course has open ends but the

flaps prevent the containers 11 from sliding out of the ends because each flap 32 engages the base tuck 13 of its associated container 11 and prevents movement of the container 11 relative to the sleeve in the direction of the adjacent open end. It will of course be readily appreciated that the concept would be applied to other arrays of similar containers. For example a 2 X 3 array with two containers adjacent the open ends would still require only four flaps 32 to secure only the four containers adjacent the ends. Extra flaps, however, could be provided to increase security. Also other arrays such as 3 X 3 are possible and one example of such an arrangement is shown in figure 4. In this arrangement suitable hinged flaps 32 are provided in the bottom panel so as to engage the tucks 13 of the middle row of containers. It will be appreciated that any rectangular array of containers can be provided for.

Also the actual form and precise location of the flaps 32 can be changed, although best results are obtained with an edge 33 which corresponds with the angled edge 14 of the tuck 13. Whilst the flaps 32 are shown in the above example as being cut primarily from the side portions 17, 18 it is also possible that the flaps could be cut entirely from the bottom panels or the side portions as well as any combination thereof. Also it is possible to use a single flap of suitable shape to secure two or more containers 11 such that it is not necessary to have one flap 32 per container 11 being positively secured.

In addition of course the illustrated interconnecting means between the bottom panels could be replaced by other interlocking formations or even adhesive. Furthermore the interlocking could be provided on any face of the sleeve and need not be provided adjacent the flaps.