GB2281555A - Lined cartons - Google Patents

Abstract

A lined carton is formed of a rectangular cartonboard sleeve (18A) and an internal liner (20A) attached to the internal surface of the sleeve by glueing. The glued attachment of the liner to the sleeve is terminated along a limiting line (50) which extends obliquely across the panels (10, 12) of the sleeve in such a way that the act of erecting the carton from flat to tubular form withdraws the projecting base of the liner into the sleeve, so enabling the base closure of the sleeve to be formed as though for an unlined carton. <IMAGE>

Description

"LINED CARTONS This invention relates to lined cartons.

Cartons having internal liners are well known for packaging powders and other particulate or lumpy products.

Such cartons are manufactured by forming a flattened tube of e.g plastics or paper material to provide the liner, placing the flattened tube on a preglued blank of cartonboard, and thereafter forming up the blank around the liner so as to bond the liner material to the blank and attach side margins of the blank to one another. The blank is therefore converted to flattened tubular form, and can subsequently be erected to form a sleeve having the liner generally conforming to its interior surface.

Usually the carton is of rectangular cross-section, having four sides arranged in two pairs of mutually opposed sides.

In addition to the operations described above, further operations are required in the formation of a lined carton to provide the carton with closures at its top and bottom ends. The base closure in particular requires the bottom end of not only the carton sleeve but also the liner to be closed. The present invention is of particular application to cartons in which the bottom end of the liner is closed independantly of the sleeve either aEter or before the sleeve is formed by folding the flat, glued blank around it.

The base closure of the liner is formed by a transverse fin seal which is made across the bottom of the liner, usually by heat-sealing; on the other hand, the base closure of the sleeve is formed from inturned flaps which are glued together in a suitable manner.

In the formation of the base closure of the carton it has hitherto been necessary to push the bottom end of the liner upwardly into the sleeve either by hand or using the flaps from which the base closure of the sleeve is being formed. In either event the liner requires an additional operation to be performed over and above those which would be required for the erection of an unlined carton.

As one of its objectives the present invention seeks to provide a base closure configuration for a lined carton, which can be erected by the constant motion equipment which is now available. Accordingly, therefore, the invention provides a lined carton, which comprises a tubular sleeve and an internal liner attached to the sleeve, the carton being formed as a flattened tube having folded side edges and erectable to form a faceted tube for which the said folded side edges provide two of the corners, for forming a base closure for the carton the sleeve having a plurality of flaps attached along a transverse fold line and the liner having a transverse fin seal which projects beyond the transverse fold line, characterised in that the liner is attached to the sleeve along a line of attachment which extends circumferentially of the carton, the disposition of the line of attachment in relation to the transverse fold line being such that when the carton is erected from flattened to tubular form the projecting part of the liner is drawn at least substantially into the sleeve.

A particular application of the invention is to cartons which have a rectangular cross-section after erection, and in accordance with the invention there is accordingly provided a lined carton, which comprises a tubular sleeve and an internal liner attached to the sleeve, the carton being formed as a flattened tube having folded side edges and erectable to tubular form with a rectangular cross-section, the said folded side edges then forming a first pair of opposed corners, and a pair of other fold lines of the flattened tube forming a second pair of opposed corners, for forming a base closure for the carton the sleeve having a plurality of flaps attached along a transverse fold line and the liner having a transverse fin seal which projects beyond the transverse fold line, characterised in that the liner is attached to the sleeve along a line of attachment which extends circumferentially of the carton from adjacent the junctions of the said folded side edges with the said transverse fold line and from there extends in each direction obliquely away from the transverse fold line to intersection with the said other fold lines, between the said line of attachment and the transverse fold line the liner being unattached to the sleeve whereby when the is erected from flattened to tubular form the part of the liner is drawn at least substantially into the sleeve.

A lined carton in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig.l shows a flat carton blank having a preformed liner laid onto it during the creation of the lined carton in the flat form in which it is despatched from the carton manufacturer to the packer; Fig.2 shows the completed pack formed by erecting the carton to tubular form, filling it with product, and sealing it closed at its ends; and Fig.3 is an enlarged view showing the pack as seen from below but with the base closure of its sleeve removed to reveal detail of the liner within.

A carton for a particulate or lumpy product such as dog food pellets is shown in Fig.2 to be cuboid, having major and minor pairs of opposed rectangular side panels 10, 12, a flat rectangular base 14 and a flat rectangular top 16. These panels are provided by an outer sleeve 18 in the form of a four-sided tube of rectangular cross-section and made of a substantially rigid cartonboard material, the carton further having an internal liner 20 made of thin plastics film in tubular form, which is located within the sleeve and attached by glue to the inside faces of the side panels 10, 12 so as to conform generally to the interior of the sleeve.

As shown in Fig.l in which the sleeve 18 is shown as a flat carton blank 18R, the side panels 10, 12 are hinged to one another along parallel hinge lines 22, 24 and 26.

In addition, a narrow glue flap 28 is hinged by a further hinge line 30 to one side edge of the blank. These hinge lines 22, 24, 26 and 30 form the four corners of the erected sleeve 18.

The base 14 and top 16 of the sleeve 18 are provided by end closures each formed from inwardly folded and superimposed glue flaps. The glue flaps of the base closure, denoted in Fig.l by the reference numerals 32A, 32B for the major and minor flaps respectively, are hinged to respective ones of the side panels 10, 12 along a common transvese score line 34, whereas the corresponding glue flaps 36A, 36B of the top closure are hinged to the side panels along a further transverse hinge line 38.

The liner 20 has an open top end defined by a free edge 42 which lies just short of the carton top 16. The bottom end of the liner is closed by a base closure formed by a fin seal 44 which extends transversely of the liner and is formed by heat-sealing together the plies of the flattened tube of plastics material. As will be understood from Fig.l, in the carton in its flat form the fin seal lies beyond the hinge line 34 in relation to the panels 10, 12 of the blank 18A.

In the creation of the carton the flat carton blank 18A has glue laid down on selected areas of its inner surface, that is, that surface which faces the reader in Fig.l. The flat liner, denoted 20A in Fig.l for ease of understanding, is then placed on top of the blank, its dimensions and position being such that it covers one major panel 10 and the adjacent minor panel 12 with its free edges 42, 46 and 48 lying just inboard of the respective hinge lines 38, 22 and 26 of the blank but with the bottom end of the liners destined to be formed with the fin seal 44, projecting beyond the hinge line 34. (See Fig.l).The blank is then folded around the liner along the hinge lines 22, 26, so that its inner surface becomes glued to the outside surface of the liner as required and, at the same time, the glue flap 28 becomes glued to the free opposite side margin of the blank to create the sleeve 18 in its flattened form. The fin seal 44 is then formed, access being obtained by folding back the upper flaps 32A, 32B. The carton is then ready for despatch to the packer, who will erect it to tubular form, fill it with product and seal closed its ends to produce a pack for retail consumption. In a modification the fin seal 44 is formed before the liner is placed on the glued blank.

As thus far described the carton is conventional.

However, for high speed packaging it is desirable for the packer to form the pack by a machine which can perform the necessary erecting, filling and closing operations while the carton is moving at a constant speed. One such machine is marketed worldwide by Acma and Cinzani SpA as their "Constant Motion Cartoning Machine".

Usually, the presence of the fin seal 44 below the score line 34 would prevent a machine of the kind recited above from being used in relation to the carton 18.

However, the glued attachment of the liner to the major and minor panels 10, 12 terminates along a continuous line 50 which forms its lower limit. It will be seen that this limiting line extends rectilinearily but obliquely across each of the four panels. It extends from the junctions of the fold lines 22, 26 with the fold line 34, and from these extends obliquely in each direction across the adjacent panel 10 or 12 to intersect each fold line 24 and 30 at a height 'h' from the fold line 34.

The height 'h' is so chosen in relation to the width 'w' and depth 'd' of the carton that the act of erecting the carton from its flat form to its tubular form automatically withdraws the fin seal 44 of the liner at least substantially into the carton and above the fold line 34. By virtue also of the termination of the liner below the fold line 38 at the top of the carton, the carton, insofar as the erection, filling and closing operations are concerned, may therefore be "seen" by the constant motion machine as an unlined carton, and in particular no additional operation is required to push the projecting bottom end of the liner into the carton before the base 14 can be formed. Filled packs can accordingly be produced at high rates of production.

A feature which is shown in the drawings but so far has not been described is a longitudinal seam 52 which extends longitudinally of the liner 30 between its free top edge 42 and its fin seal 44. The liner is accordingly fabricated from plastics film which is folded on itself.

As an alternative, however, the liner may be formed as a cut length of a blown tubular plastics film, and accordingly has no seam 52.

The invention has been particularly described with reference to the drawings in relation to a carton having a rectangular cross-section, that is to say, having its sleeve in the form of a faceted tube with four sides disposed in two pairs of mutually opposed sides. However, the invention may also be applied to cartons having a number of sides greater than four; as with the described embodiment the cartons are erected from a flattened tube the side edges of which form two of the corners of the erected sleeve.

Claims (7)

CLAIMS:

1. A lined carton, which comprises a tubular sleeve and an internal liner attached to the sleeve, the carton being formed as a flattened tube having folded side edges and erectable to form a faceted tube for which the said folded side edges provide two of the corners, for forming a base closure for the carton the sleeve having a plurality of flaps attached along a transverse fold line and the liner having a transverse fin seal which projects beyond the transverse fold line, characterised in that the liner is attached to the sleeve along a line of attachment which extends circumferentially of the carton, the disposition of the line of attachment in relation to the transverse fold line being such that when the carton is erected from flattened to tubular form the projecting part of the liner is drawn at least substantially into the sleeve.

2. A lined carton, which comprises a tubular sleeve and an internal liner attached to the sleeve, the carton being formed as a flattened tube having folded side edges and erectable to tubular form with a rectangular cross-section, the said folded side edges then forming a first pair of opposed corners, and a pair of other fold lines of the flattened tube forming a second pair of opposed corners, for forming a base closure for the carton the sleeve having a plurality of flaps attached along a transverse fold line and the liner having a transverse fin seal which projects beyond the transverse fold line, characterised in that the liner is attached to the sleeve along a line of attachment which extends circumferentially of the carton from adjacent the junctions of the said folded side edges with the said transverse fold line and from there extends in each direction obliquely away from the transverse fold line to intersection with the said other fold lines, between the said line of attachment and the transverse fold line the liner being unattached to the sleeve whereby when the carton is erected from flattened to tubular form the part of the liner is drawn at least substantially into the sleeve.

3. A carton according to claim 1 or claim 2, wherein the fin seal is formed by heat-sealing.

4. A carton according to any preceding claim, wherein the liner has a longitudinal seam.

5. A carton according to any preceding claim, wherein for forming a top closure for the carton the sleeve has a plurality of flaps attached along a further transverse fold line, the liner having an open top end defined by a free edge which lies adjacent the said further transverse fold line.

6. A lined carton, substantially as herein described with reference to the accompanying drawings.

7. A product-filled pack formed from a carton as claimed in any preceding claim.