Field of Invention

The present invention relates to cartons, to blanks suitable for the construction of such cartons and to the methods of manufacturing cartons.

Background to the Invention

Tubular packages made from card and the like have been in use for many years. There are a variety of ways of forming the sleeve of a tubular package. The most common is to helically wind strips of cardboard around a former and then convolutely apply a printed label, usually in paper. Tubular packages made in such a way have the advantage of being very strong, often referred to as radial strength and/or also vertical compressive strength. The disadvantage of such containers is that they have to be supplied in an erected form thus require large amounts of storage space and incur high transit costs. These containers are typically round and can be curved and as such give a pleasing and differentiated shape. It would be advantageous to supply a curved container in flat form. Such containers are known, but the material from which they are made tends to be thin and pliable and the resultant container lacks the physical strength properties of existing tubular packages.

Until now, it has not been possible to provide a strong container with a substantially curved shape that can be supplied in flat form for simple erection.

It is an aim of preferred embodiments of the present invention to obviate or overcome disadvantages of the prior art, whether such prior art or disadvantages are referred to herein or otherwise. Summary of the Invention

According to the present invention in a first aspect, there is provided a blank for a tubular carton having a bottom, the carton comprising a rectangular zone comprising two folding lines perpendicular to a side thereof corresponding to the bottom of the container, and diagonal lines of weakness in the rectangular zone extending for at least part of the length of the rectangular zone.

Suitably, the lines of weakness extend for the full length of the carton from the bottom to the opposing top. Alternatively, the lines of weakening extend for a part of the length of the carton.

Suitably, the lines of weakness are one of straight or curved.

Suitably, the blank further comprises a gluing edge extending from the rectangular zone, which gluing edge comprises a line of weakness configured to align with a line of weakness in the zone during construction thereof.

Suitably, the material of the carton is corrugated board. Suitably, the board thickness is from 800μ to 1500 μ.

Suitably, the blank additionally comprises truncated, spaced, pairs of lines of weakening substantially parallel to the bottom edge of the carton. Suitably, the truncated lines are located in the top half of the carton. Suitably, the truncated lines of weakness extend less than the width of a sub-zone of the blank, the sub-zones being defined by edges and/or fold lines of the blank. These can provide finger holds.

Suitably, there is a gluing edge on one of the sides perpendicular to the side corresponding to the bottom of the container, and suitable to form the external wall thereof. Suitably, a series of panels, project from a side of the rectangular zone, corresponding to the bottom of the container, suitable to form the base thereof.

Advantageously the container can be put on the market in a flattened shape and to be opened in its final tridimensional shape upon use.

According to a feature of the invention, the diagonal weakening lines prevent the carton from cracking or deforming when being set up into the final tridimensional shape. Consequently according to another feature of the invention, thicker and or stronger material can be used to construct the container. Such materials can include corrugated materials which typically do not lend themselves to being formed into curved shaped containers.

The rectangular zone having a number of curved or straight weakening lines running substantially diagonally from the top to the bottom of the rectangular zone facilitates the shaping of the container from square, rectangular, hexagonal or triangular, but not limited to these base configurations only or even to regular shapes, to round or elliptical but not limited to these shapes, at the top.

This embodiment thus enables an erected market presentation which achieves similar aesthetic appearance to traditional tubular packages without their incumbent disadvantages as referred to in the background to the invention.

According to the present invention in a second aspect, there is provided a carton assembled from a blank according to the first aspect of the invention.

According to the present invention in a third aspect, there is provided a method of construction of a carton comprising the steps of providing a carton blank according to the first aspect of the invention and constructing the carton. Brief Description of the Drawings

This invention will now be described in greater detail in connection with the accompanying drawings wherein:

Fig.1 shows a blank for obtaining a substantially cylindrical, strong carton container capable of being delivered in flat form according to a first embodiment of the present invention.

Fig 2. shows the first mounting step of the container starting from the blank of Fig. 1.

Fig.3 shows the final mounting step of the container starting from the blank of Fig. 1.

Fig.4 shows a blank for obtaining a substantially cylindrical, strong container capable of being delivered in flat form according to a second aspect of the present invention.

Fig.5 shows a blank for obtaining a substantially cylindrical, strong container capable of being delivered in flat form according to a third embodiment of the present invention.

Figure 6 shows a blank of a fourth embodiment of the present invention.

Description of the Preferred Embodiments

Fig. 1 shows a blank 1 according to a first embodiment of the present invention. The blank 1 has a zone 2 of rectangular shape intended to form the external wall of a container. The zone 2 is divided into four rectangular portions: A, B, C, D by two cross folding lines 3 and 4 and centre line 5. The rectangular zone 2 has on one side thereof, in this case on the portion D, a gluing edge L. Projecting from the lower rectangular side of zone 2 is a strip generally designated by E, divided into four segments E1 , E2, E3, E4, each of which forms one of the tongues T intended to form the bottom of the container and bearing here the reference numbers 6,7,8,9. This strip E is separated from the rectangular zone 2 by a longitudinal folding line P. The tongues 6,7,8,9 have a specific shape adapted to form an engagement means of the bottom of the made-up container. The portions A, B, C and D each have straight weakening lines 10, 11 , 12, 13, running diagonally from the bottom of zone 2 at strip E to the top of zone 2, the end distal from the strip E. The weakening lines 10 and 11 substantially converge at the top of zone 2 and also converge with cross folding line 3. The weakening lines 12 and 13 substantially converge at the top of zone 2 and also converge with cross folding line 4.

The weakening lines 12 and 13 are formed in a similar way to fold lines by a creasing tool. The weakening lines provide a line along which the carton will tend to fold in the course of making-up the carton. The weakening lines form a stress relief function in that they encourage the carton to fold or yield in this area to prevent either cracking or irregular buckling/bulging

Fig. 2 shows the first mounting step of the container starting from blank 1. This step consists in folding the blank along the folding lines 3, 4 and 5 and in gluing the gluing edge L to the opposite outer side of the rectangular zone 2 so as to obtain a closed element to form the container in the flattened condition in which it is put on the market.

Fig.3 shows the final mounting step of the container. This step consists of opening the so glued blank by exerting an inwardly directed pressure on the cross folding lines 3 and 5 and engaging in a known manner the flaps E1 , E2, E3, E4 to form the base. As a final step, and generally once a product has been loaded into the made-up container, a shaped closure is inserted into the opposite end of the container corresponding to the top.

Fig. 4 shows a blank 1 according to a second embodiment of the present invention. The same reference numerals/letters are used for corresponding elements of the container. The blank 1 has a zone 2 of rectangular shape intended to form the lateral wall of the container. This zone 2 is divided into four rectangular portions: A, B, C, D by two cross folding lines 3 and 4, and centre line 5. The rectangular zone 2 has on one side thereof, in this case on the portion A, a gluing edge L. Projecting from the lower rectangular side of zone 2 is a strip generally designated by E, divided into four segments E1 , E2, E3, E4, each of which forms one of the tongues T intended to form the bottom of the container and bearing here the reference numbers 6,7,8,9. This strip E is separated from the rectangular zone 2 by a longitudinal folding line. The tongues 6,7,8,9 have a specific shape adapted to form the engagement means of the bottom of the container. The portions A, B, C and D each have curved weakening lines 14, 15, 16, 17, running diagonally from the bottom of zone 2 to the top of zone 2. The weakening lines 14 and 15 substantially converge at the top of zone 2 and also converge with cross folding line 3.

The mounting of the container according to Fig. 4 occurs exactly in the same manner of the container of Fig. 1.

Fig. 5 shows a blank according to Fig. 1 , the sole difference being given by the fact that the diagonal weakening lines 18, 19, 20, 21 do not run completely to the top or bottom of zone 2. It will be appreciated that any combination of different lengths of weakening lines can be incorporated. The mounting of the container according to fig. 5 occurs exactly in the same manner of the container of Fig. 1.

Fig. 6 shows a blank according to Fig. 1 with additional pairs of parallel truncated lines of weakening extending parallel to the bottom (and top) edge(s). The pairs of weakening lines are labelled 25, 26, 27 and 28. These lines of weakening provide finger holds, between each pair, especially useful when the carton container contains a heavy object such as a glass bottle filed with liquid. In each embodiment the weakening lines run generally for at least part of the length between the corners defined by the fold lines or edges of the zone 2. Thus the zone 2 can be regarded as split up into separate sub-zones A, B, C and D. Thus, the weakening lines are not parallel to the edges of the zone 2.

In each embodiment a corresponding diagonal weakening line is provided on the gluing edge L.

Of course, only four embodiments of the present invention have been described. It is apparent that the folding lines can be more or less in number. From the foregoing it can be seen that by means of the blank according to the present invention, it is possible to obtain a strong cardboard container, or the like, having a substantially curved shape which can be supplied in flat form for simple manual or automatic erection.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.