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

Background to the invention Radiused cornered paperboard containers are commonly used in packaging a variety of articles such as bottles, cookies, confectionery, granular foodstuffs, potato chips and other such articles/items. The majority of these containers are manufactured in remote locations and shipped in a set up form to the point of product packing. In other cases expensive dedicated machinery is set up at the side of the packing operation to manufacture the containers and thus avoid the shipping costs and associated logistical problems.

Square or rectangular containers however are produced using folding carton technology and these containers are shipped flat to the point of packing. Such containers can be easily erected by hand or by simpler less expensive machinery.

GB 2451281 discloses a round or curved carton. This carton however has a complicated base structure which is difficult and costly to glue into its desired flat or knock down state.

An aim of the present invention is to provide a radiused cornered container with a strong and substantially flat base or lid which is less complicated in its construction and method of manufacture.

GB 2451281 has a base which sits recessed from the bottom of the carton. It is advantageous to have the base structure resting on the ground when erected. The load of the product is transferred in this case directly to the surface below rather than through the base construction itself.

It is therefore a further aim of the present invention to provide a base for a radiused cornered carton which sits substantially flush with the surface on which it sits. Such a carton will be able to contain products of significantly more weight.

It is therefore an aim of preferred embodiments of the present invention to obviate or overcome a disadvantage of the prior art, whether such prior art or disadvantage is referred to herein or otherwise.

Summary of the Invention According to the present invention in a first aspect there is provided a method of construction of a carton from a blank, the blank comprising a side wall having free ends, the side wall comprising a first panel connected to a second panel, a hinged base panel connected to the first panel and an inner base panel hingedly connected to the second panel, the method comprising the steps of folding the hinged base panel above the first panel, folding the inner base panel over the second panel, folding the hinged base panel about the central crease line, affixing part of the of the reverse of the hinged base panel to a corresponding part of the face of the inner base panel comprising folding the first and second panels relatively towards each other, fixing the free ends of the side wall and moving the hinged locking base panel and the inner base panel to form a base of the carton, whereby the hinged base panel and inner base panel are configured to form a base at the bottom of the carton.

Suitably, side locking base panels are pushed through corresponding apertures in the hinged base panel. Preferably the ends of the side locking base panels are provided with one way entry barbed ends to prevent them from disassembling once constructed. Suitably, the carton is provided with a plurality of crease or weakening lines located in the areas where the radius corners occur, designed to allow the carton to curve uniformly at the corners. Suitably, the carton is erected over a former or mandrill of substantially the same shape as the finished carton profile.

Where there are two panels forming the side wall, the free end of the first panel is affixed to the free end of the second panel, but if there are more than two panels, the relevant free ends are fixed together.

The partly assembled carton is placed over a mandrill or forming tool and pressure applied to the two opposite creases to open up the carton and form the base. The side locking panels are folded over and secured to the hinged base panel.

According to the present invention in a second aspect there is provided a carton comprising a side wall comprising a first panel connected to a second panel, the first and second panels having free ends, a hinged base panel hingedly connected to the first panel and an inner base panel hingedly connected to the second panel, the hinged base locking panel being folded along a hinge line thereof and affixed to the inner base panel, the free ends of the sidewall being fixed to each other, whereby the hinged base panel and inner base panel are configured to form a base at the bottom of the carton. In an alternative embodiment the hinged base panel is replaced by an inner base panel with no hinge. The carton is glued at its free ends only and placed over a mandrill or former. The inner base flap is folded over first and is provided with cutouts to receive one or more side locking panels. Finally an outer base flap is folded over and glued to at least the inner base panel but additionally can be glued also to one or more side locking panels. Suitably, the hinged base panel, the inner panel and /or the outer base panel are substantially square or rectangular in cross sectional shape with radiused corners. Suitably, the hinged base panel and the inner base panel can be a variety of radiused cornered shapes such as square, rectangular, triangular etc in cross- section.

Suitably, the inner base panel comprises at least one flap extending therefrom, configured to be folded to lie against the inside of the first panel or the second panel in the made-up carton. Suitably a flap extends from an end of the inner base panel and a second flap extends from an opposing end of the inner base panel, whereby the first flap is configured to be folded to lie against the inside of the first panel in the made up carton and the second flap is configured to be folded to lie against the inside of the second panel in the made up carton.

Suitably, a first shaped flap extends from the edge of the first panel opposite the edge from which extends the hinged base panel and a second shaped flap extends from the corresponding edge of the second panel, whereby the first shaped flap and the second shaped flap provide a plurality of recessed arms.

The invention extends to carton blanks suitable for making a carton according to the second embodiment of the invention. Brief Description of the Drawings

The present invention will now be described, by way of example only, with reference to the drawings that follow; in which: Figure 1 is a plan view of a blank for producing a carton according to a first embodiment of the present invention. Figure 2 is a plan view of a blank for producing a carton according to a second embodiment of the present invention.

Figure 3 is a plan view of a blank for producing a carton according to a third embodiment of the present invention.

Figure 4 is a flow diagram illustrating a method of constructing a carton according to the present invention. Figure 5 is a plan view of a made-up carton according to the first embodiment of the invention.

Description of the Preferred Embodiments Referring to figure 1 of the accompanying drawings, there is shown a one piece carton board blank 2 comprising a side wall 4 The side wall 4 comprises a first panel 6 and a second panel 8. In this case, the second panel 8 is also an end panel. First panel 6 is generally rectangular and is hingedly connected to the similarly shaped second panel 8 by a fold line 10 along an edge thereof forming a hinged connection therebetween. Extending from the short edge of the first panel 6 distant from fold 10 is glue flap 12 connected to the first panel 6 by fold line 14.

Extending from first panel 6 is a hinged base panel 20, with a hinge line at 22, which hinged base panel 20 is hingedly connected to first panel 6 by a fold line 24. The portion of the base panel defined by crease lines 22 and 24 forms a first part 32 of said base panel 20 and the remainder of said base panel 20 forms a second part 34 of said base panel 20 Also extending from second panel 8 is an inner base panel 26 hingedly connected to second panel 8 by a fold line 28. Extending from glue flap 12 and first panel 6 is first side locking base panel 40 hingedly connected by a fold line 44. Extending second panel 8 is a second side locking base panel 42 hingedly connected by a fold line 46.

The hinged base panel 20 and the inner base panel 26 extend from the edge of the respective panels 6, 8 and as will be explained further below are configured to form a base at the bottom, when the carton is stood upright, of the constructed carton. That is, the base constructed by the hinged base panel 20 and the inner base panel 26 is not recessed within the carton when it is made up.

A method of construction of the blank 2 as described above will now be set out with reference to Figure 4. Typically construction is carried out using carton gluing machinery but can be done by hand also. The second part 34 of hinged base panel 20 is folded back (step 100) initially away from first panel 6 so that the two parts 32, 34 of hinged based panel 20 lie in substantially face to face relationship

Adhesive is applied (step 102) to the reverse of the second part 34 of hinged base panel 20, or alternatively to the corresponding face of inner base panel 26.

Then the carton is folded (step 104) about central crease line 10 and the outside glue flap 12 is moved (step 106) to contact a strip of glue to form the loop of the carton. First and second panels 6, 8 are thereby fixedly connected to form a carton and inner base panel 26 is fixed to hinged base panel 20 as a result of the aforementioned application of adhesive.

The carton as described above can be transported in a flat configuration with panels 6, 8 pressed together and pushed into a useable configuration with pressure applied to fold lines 10 and 14. Here inner base panel 26 is pressed (step 108) down towards the bottom of the carton to lock the carton into shape. The inner base panel 26 overlies the hinged base panel 20. Finally the side locking base panels 40, 42 are pushed (step 1 10) down into corresponding apertures 50, 52 in the hinged base panel 20.

The resultant base is substantially flat and of uniform thickness and is able to resist pressure and thus damage from any directional force.

Suitably, the carton is erected over a former or mandrill of substantially the final erected shape. The weakening lines 60 on the carton are positioned so as to correspond with the radiused corners on the mandrill or former.

Referring to Fig 2 there is a second embodiment. To the extent possible in the following embodiments, like reference numerals are used for corresponding components. In this embodiment there is no requirement to fold back the second part 34 of hinged base panel 20 prior to gluing to inner base panel 36.This has an advantage in terms of the mechanical gluing operation in that it makes it less complex.

Referring to figure 2 there is shown a further alternative embodiment. There is shown a one piece carton board blank 2 comprising a side wall 4. The side wall 4 comprises a first panel 6 and a second panel 8. In this case, the second panel 8 is also an end panel. First panel 6 is generally rectangular and is hingedly connected to the similarly shaped second panel 8 by a fold line 10 along an edge thereof forming a hinged connection therebetween. Extending from the short edge of the first panel 6 distant from fold 10 is glue flap 12 connected to the first panel 6 by fold line 14.

Extending from second panel 8 is an inner base panel 72, with a hinge line at 28, which outer base panel 70 is hingedly connected to first panel 6 by a fold line 24.

The carton is folded about central crease line 10 and the outside glue flap 12 is moved to contact a strip of glue to form the loop of the carton. First and second panels 6, 8 are thereby fixedly connected to form a carton. The flat carton is placed over a suitably shaped former or mandrill and opened up. The creased weakening lines 60 are located to coincide with the radiused corners of the mandrill. The inner base panel 72 is folded about crease line to overlie the top of the mandrill .Side locking panels 80, 82 are folded about crease lines 84, 86 and are locked or glued to inner base panel 72. The locking means is by way of extensions from the side locking panels 80, 82 slotting into apertures 90, 92 in the inner base panel 72. Finally the outer base panel 70 is folded about crease line 24 and glued to the inner base panel 72. In addition the outer base panel 70 can be glued to one or more of the side locking panels.

Referring to Fig 3 there is a third embodiment. In this embodiment there are no locking base panels and additional rigidity is provided by ear flaps on the inner base panel 26. This has an advantage in terms of the mechanical gluing operation in that it makes it less complex.

Referring to figure 2 there is shown a further alternative embodiment. There is shown a one piece carton board blank 2 comprising a side wall 4. The side wall 4 comprises a first panel 6 and a second panel 8. In this case, the second panel 8 is also an end panel. First panel 6 is generally rectangular and is hingedly connected to the similarly shaped second panel 8 by a fold line 10 along an edge thereof forming a hinged connection therebetween. Extending from the short edge of the first panel 6 distant from fold 10 is glue flap 12 connected to the first panel 6 by fold line 14. Extending from second panel 8 is an inner base panel 80, with a hinge line at 28. Extending from first panel 6 is a hinged base panel 82, with a hinge at 22, which hinged base panel 82 is hingedly connected to first panel 6 by a fold line 24. Extending from either distal end of inner base panel 80 are ear flaps 84, 86 which are generally semi-circular. Extending from the edge of the first panel 6 opposite hinged base panel 82 is a T-shaped flap 88 and a corresponding T-shaped flap 90 extends from the corresponding edge of second panel 8. The carton is constructed in the same manner as that for the embodiment of Figure 1 , except that there are no locking panels and no lid. During construction the ear flaps 84, 86 are folded upwardly so as, in the constructed carton, to lie against the first panel 6 and second panel 8, respectively. The ear flaps 84, 86 provide additional structural integrity to the carton.

The T-shaped flaps 88, 90 are folded down to lie against the first panel 6 and second panel 8, respectively. The T-shaped flaps 88, 90 include recessed ends 92 which can be used to help secure a lid to the carton. The T-shaped flaps 88, 90 can be glued down to secure them in place.

Referring to Fig 5 there is shown a plan view of a made-up carton 100, illustrating the curved nature of the radiused corners of a "square" carton.

The constructions mentioned referred to as a base can equally form a lid or top or even a side of a finished container.

A wide variety of shapes can be achieved according to embodiments of the present invention. These can be with two panels or more. 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, or to any novel one, or any novel combination, of the steps of any method or process so disclosed.