Flanged cardboard container

Abstract

A flanged cardboard container (1), comprising a tray formed by a first die-cut element (10) and coupled to a second die-cut element (20), the first die-cut element (10) being constituted by a polygonal bottom (11) with a plurality of flaps (12a-12d) folded along straight sides (3) of the bottom (11) in order to define the side walls of the tray; the second die-cut element (20) comprises a collar (21) provided with a plurality of protruding tabs (22) which are coupled to the folded flaps (12a-12d) of the first die-cut element (10) in order to form a flange of the tray; the tabs (22) are folded along a substantially curved line (23), and at least one of the flaps (12a-12d) comprises, between the straight side (3) of the bottom (11) and the upper edge (16), at least one relief crease (13, 14) adapted to facilitate the deformation of the flap (12a-12d) from the straight side (3) of the bottom toward the upper edge (16), which is curved by the coupling with the tabs (22).

Description

[0001] The present invention relates to a flanged cardboard container, particularly of the type lined internally with a barrier film and usable to contain food products.

[0002] It is known to provide cardboard trays that are flanged and lined internally with film in order to contain, for example, food products and to be subsequently sealed in the upper region with a covering layer that is fixed on the flange. Trays of this type, provided by folding and gluing die-cut elements, are known for example from WO1999 / 67143 A2.

[0003] One drawback of this type of solutions is that the flange of the tray must have a polygonal shape that substantially corresponds to the shape of the bottom, so that each edge of the polygonal shape of the flange is substantially parallel to the straight folding line of the side wall that, from the bottom of the tray, is coupled to that edge of the flange.

[0004] The aim of the present invention is to provide a flanged cardboard container, preferably of the type lined internally with a barrier film, that is capable of avoiding the drawbacks of the background art in one or more of the aspects mentioned above.

[0005] Within this aim, an object of the invention is to provide a flanged cardboard container, provided with a flange having a curvilinear shape, for example a circular or oval one.

[0006] Another object of the invention is to provide a flanged cardboard container in which the barrier film applied internally to the container can adhere effectively also along the edges formed between the adjacent side walls.

[0007] Another object is to provide a flanged cardboard container that can be obtained by means of conventional machines of the paper-making and packaging industries.

[0008] Another object of the invention is to provide a flanged cardboard container that has small dimensions, corresponding to those of plastic pots such as those for yogurt or for sauces.

[0009] Another object of the present invention is to overcome the drawbacks of the background art in a manner that is alternative to any existing solutions.

[0010] Not least object of the invention is to provide a flanged cardboard container that is highly reliable, relatively easy to provide and at competitive costs.

[0011] This aim and these and other objects that will become better apparent hereinafter are achieved by a container according to claim 1, optionally provided with one or more of the characteristics of the dependent claims.

[0012] Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of the container according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein: Figure 1 is a view of a first die-cut cardboard element for providing a container according to the invention; Figure 2 is a view of a second die-cut cardboard element to be coupled to the first die-cut element after at least one folding operation; Figure 3 is a view of a female die for providing a container according to the invention starting from the die-cut elements of the previous figures; Figure 4 is a view of a step of folding the first die-cut element within the female die; Figure 5 is a view of a tray obtained with the folding of the first die-cut element; Figure 6 is a view of the application of the second die-cut element on the tray of the preceding figure; Figure 7 is a view of a step of folding the second die-cut element on the side walls of the tray; Figure 8 is a view of a step of applying a barrier film on the blank of the preceding figure; Figure 9 is a view of the cardboard container lined internally and on the flange with the barrier film of Figure 8.

[0013] With reference to the figures, a flanged cardboard container according to the invention, generally designated by the reference numeral 1, comprises a cardboard tray formed by a first die-cut cardboard element 10, which is folded and coupled to a second die-cut cardboard element 20.

[0014] The grammage of the cardboard is preferably lower than 400 g / m 2< .

[0015] The first die-cut element 10 is provided with a polygonal bottom 11 that constitutes the base of the tray and, consequently, of the container 1.

[0016] The first die-cut element 10 comprises, moreover, flaps 12a, 12b, 12c, 12d around the polygonal bottom 11 which, folded along the sides 3 of said bottom 11, correspond to respective side walls of the tray and, consequently, of the final container 1.

[0017] The polygonal bottom 11 of the tray defines bottom edges of the container 1, at the folding line 3 of the flaps 12a, 12b, 12c, 12d, which are straight.

[0018] The polygonal bottom 11 preferably has a square shape, but in other preferred embodiments (not shown) it may have rectangular, rhomboid or triangular shape, or may have a greater number of sides or edges.

[0019] The polygonal bottom 11 is formed on the first die-cut element 10 by straight folding lines 3 that surround it. A respective flap 12a-12d extends from each folding line 3.

[0020] Optionally, each folding line 3 of the flaps 12a-12d with respect to the bottom 11 can comprise one or more notches 18, in order to facilitate the operation of folding the flaps 12a-12d to form the tray.

[0021] The flaps 12a-12d can be arranged on sides of the polygonal bottom 11 which are mutually opposite in pairs, or on the larger sides, or pairs of sides, of the polygonal bottom 11, or on all the sides of the polygonal bottom 11. Furthermore, the flaps 12a-12d have a respective free upper edge 16 that is spaced from the straight folding line 3 by an equal amount for all the flaps 12a-12d.

[0022] Each flap 12a-12d preferably has a flared profile, with the straight lateral edges 17 that diverge away from the polygonal bottom 11 and toward the upper edge 16 that connects them.

[0023] The first die-cut element 10 is obtained from a sheet of cardboard by blanking, using a die-cutter, portions of the sheet so as to leave an essentially corolla-like shape with the polygonal bottom 11 placed at the center and surrounded by the flaps 12a-12d.

[0024] In the preferred embodiment shown, the first die-cut element 10 essentially has a Greek cross-like shape or cross pattée-like shape.

[0025] The second die-cut element 20 essentially consists of a collar 21 having a plurality of tabs 22 that protrude inward from respective folding segments, which are short enough to form, as a whole, a closed broken line 23 that forms essentially a closed curved line, more precisely a substantially circular one, as in the illustrated case, in which the collar 21 is substantially an annular element. Therefore, the tabs 22, when coupled to the folded flaps 12a-12d of the first die-cut element 10 in order to form the container 1 according to the invention, are folded along a substantially circular line 23.

[0026] Groups of folding tabs 22 are coupled to each of the folded flaps 12a-12d of the first die-cut element 10 in order to form, by means of the collar 21, a continuous flange above the side walls of the container 1, as shown in Figure 9. Advantageously, the second die-cut element 20 can be oriented with respect to the tray obtained from the first die-cut element 10 so that, for each pair of adjacent folded flaps 12a-12d forming a pair of contiguous side walls of the tray, one of the tabs 22 is coupled in a bridge-like manner to the two contiguous side walls at the edge formed between them.

[0027] The coupling between the tabs 22 and the flaps 12a-12d may be achieved by virtue of the interposition of a layer of glue, but according to an advantageous aspect of the invention the application of glue can be completely avoided by lining with a barrier film the inside of the blank formed by the tray and by the collar 21 arranged on the upper rim thereof. In this case, it is in fact the barrier film that performs the anchoring function between the flaps 12a-12d and the tabs 22 abutted thereon, along the inner faces of the side walls of the container 1.

[0028] According to one aspect of the invention, each of the flaps 12a-12d comprises at least one relief crease 13 and / or 14 arranged between the straight side 3 of the polygonal bottom 11 and the upper edge 16 of the flap 12a-12d along which multiple tabs 22 are coupled.

[0029] The relief creases 13 and / or 14 are adapted to facilitate the surface deformation that the respective flap undergoes, which remains substantially flat in the region adjacent to the straight line 3 and is instead curved toward the upper edge 16 due to the coupling with the respective group of tabs 22 of the collar 21.

[0030] By virtue of the relief creases 13 and / or 14, the memory effect of the flap 12a-12d containing them is mitigated, which thus tends to maintain more easily the concave shape toward the collar 21 imposed by the coupling with the tabs 22 despite the fact that the flap 12a-12d has been obtained from a flat die-cut element 10 and is connected to a straight edge 3 at the base of the container 1.

[0031] A first relief crease is preferably provided with a substantially U-shaped crease line 13, with the two legs of the "U" that reach the upper edge 16 and diverge almost to the lateral edges 17 of the flap 12a-12d, keeping substantially parallel to said lateral edges 17. The curved base of the "U" is instead directed toward the straight side 3 of the bottom 11 and spaced from said side 3, preferably so that the area delimited by the first crease 13 and by the edge 16 constitutes most of the total area of the respective flap 12a, 12b, 12c or 12d that contains the first crease 13.

[0032] In this manner, the surface of the side wall of the container 1 between the curved base of the first crease 13 and the base edge 3 is kept substantially flat, while the surface enclosed by the first crease 13 is substantially concave, with the concavity directed toward the inside of the container 1.

[0033] The legs of the first crease 13 that are adjacent to the lateral edges 17 of the respective flap 12a-12d can advantageously have at least one relief notch 15 superimposed along the crease line 13, in order to facilitate the folding of the flap along the respective leg of the U and further improve the retention in the curved configuration of the upper region of the corresponding side wall of the container 1, particularly near the edge that would be formed with the contiguous side wall. In the embodiment shown, two notches 15 are provided along each leg of the U-like line that defines the first crease 13.

[0034] In addition to or as an alternative to the first crease 13, at least one of the flaps 12a-12d comprises a plurality of crease segments 14 along the upper edge 16, which affect transversely or perpendicularly the upper edge 16. The crease segments 14 are spaced from the straight side 3 of the polygonal bottom 11 so as to define a substantially prism-like surface on an upper band of the side wall of the container 1, i.e., along the upper edge 16 of the flap 12a-12d.

[0035] In order to manufacture the container 1 according to the invention, it is possible to resort to per se known solutions, which use a die 30 provided with a female die 31 containing an inner seat 32 having a shape and height that substantially correspond to those of the tray to be erected. The first die-cut element 10 can be spread over the seat 32, placing the polygonal bottom 11 coaxially to it. A plunger 33 pushes the bottom 11 of the die-cut element into the seat 32, causing the flaps 12a-12d to fold toward the plunger 33 along the straight sides 3 and thus shaping the first die-cut element 10 as a tray, shown in Figure 5.

[0036] The second die-cut element 20 can then be placed above and coaxially to the seat 32 or to the tray thus generated. A second plunger 34 or the same plunger 33 of the preceding step is again inserted in the seat 32 of the female die 31 to deform the tabs 22 against the inner faces of the side walls of the tray, which are formed by the folded flaps 12a-12d.

[0037] A barrier film 4, particularly a film made of thermoplastic material, is then spread over the seat 32 of the female die 31, covering the entire flange 21 of the blank temporarily present in the female die 31.

[0038] A complementary die 35 provided with heat application means is then moved closer to the female die 31, closing from above the seat 32 and generating an amount of heat suitable for thermoforming the film 4. Simultaneously, a vacuum in the seat 32 or an overpressure between the film 4 and the counter-die 35 is created in a per se known manner. The film 4 is thus deformed and made to adhere to all the internal surfaces of the blank formed by the tray and the collar 21, consequently fixing the tabs 22 to the side walls of the container 1 thus obtained.

[0039] The container 1 can then be subsequently stored or filled (for example with a food product) and sealed hermetically with a covering sheet fixed along the flange 21, using per se known techniques.

[0040] In practice it has been found that the invention achieves the intended aim and objects.

[0041] The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the accompanying claims; all the details may furthermore be replaced with other technically equivalent elements.

[0042] In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to the requirements and the state of the art.

[0043] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A flanged cardboard container (1), particularly for the containment of food products, comprising a cardboard tray formed by a first die-cut cardboard element (10) and coupled to a second die-cut cardboard element (20), the first die-cut element (10) being constituted by a polygonal bottom (11) with a plurality of flaps (12a-12d) folded along straight sides (3) of the polygonal bottom (11) in order to define the side walls of the tray, the second die-cut element (20) comprising a collar (21) provided with a plurality of protruding tabs (22) which are coupled to the folded flaps (12a-12d) of the first die-cut element (10) in order to form, by means of said collar (21), a continuous flange above the side walls of the tray, characterized in that said tabs (22) are folded along a substantially curved line (23), and in that at least one of said flaps (12a-12d) comprises, between the straight side (3) of the polygonal bottom (11) along which said at least one flap (12a-12d) is folded and the upper edge (16) of said at least one flap (12a-12d) along which said tabs (22) are coupled, at least one relief crease (13, 14) adapted to facilitate the deformation of said at least one flap (12a-12d) from said straight side (3) of the polygonal bottom (11) toward said upper edge (16), which is curved by the coupling with said tabs (22).

2. The flanged container (1) according to claim 1, wherein the flaps (12a-12d) that comprise said at least one relief crease (13, 14) are all the side walls of said tray.

3. The flanged container according to one or more of the preceding claims, wherein said at least one relief crease (13, 14) comprises a substantially U-shaped crease (13), said U-shaped crease (13) having two legs directed toward said upper edge (16) of the flap (12a-12d) that contains it and a base in an intermediate region of said flap.

4. The flanged container (1) according to claim 3, wherein the legs of said U-shaped crease (13) are adjacent to respective lateral edges (17) of the flap (12a-12d) that contains it.

5. The flanged container (1) according to claim 3 or 4, wherein said U-shaped crease (13) has at least one relief notch (15) along said legs, in order to facilitate a folding of said flap along said legs.

6. The flanged container (1) according to one or more of the preceding claims, wherein said at least one relief crease (13, 14) comprises a plurality of crease segments (14) along the upper edge (16) of said at least one flap which are spaced from said straight side (3) of the bottom in order to form a substantially prism-like surface of the flap along said upper edge (16) of the flap.

7. The flanged container (1) according to one or more of the preceding claims, wherein said substantially curved line (23) along which said tabs (22) can be folded is a broken line formed by a plurality of folding segments, each of which is at the base of a respective tab (22).

8. The flanged container (1) according to claim 7, wherein said collar (21) is substantially a flat annular element.

9. The flanged container according to one or more of the preceding claims, wherein said tabs (22) of the second die-cut element (20) are kept coupled to the folded flaps of said first die-cut element (10) by means of a barrier film (4), which covers at least said tabs (22), said flaps (12a-12d) and said polygonal bottom (11) inside said container (1).

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