GB2346869A

GB2346869A - Cartons

Info

Publication number: GB2346869A
Application number: GB0000973A
Authority: GB
Inventors: Geoffrey John Radley
Original assignee: A & R Carton; FCP
Current assignee: A & R Carton; FCP
Priority date: 1999-02-16
Filing date: 2000-01-18
Publication date: 2000-08-23
Anticipated expiration: 2020-01-18
Also published as: GB9903343D0; GB0000973D0; GB2346869B

Abstract

In manufacturing a carton, a rectangular or square blank is provided with one, or preferably a pair of cut lines 12, 14 in a width direction between respective parallel edges 4, 6. The cuts 12, 14 do not extend the full width of the blank and define end portions 16, 20 and a central portion 18. The end portions 16, 20 are folded inwardly of the blank, each about an axis parallel with the respective cut line and are then glued to the central portion 18, but only outside crease lines 38, 40. Suitable fold lines 13', 15', 42-48 are provided parallel to the edges between which the cuts 12, 14 were made to ensure that when these edges are urged together the first and third portions separate from the second portion to define straps 16, 20 the rear of a sleeve-type carton into which a tray can be inserted. The straps 16, 20 hold the tray whereas the portion 18 covers the tray and can be printed with suitable information concerning the contents of the tray.

Description

Improved Carton and Method of Construction Therefor This invention relates to an improved carton construction, and method for carton formation, and more particularly to the construction of sleeve-type cartons which are specifically adapted to receive a tray of plastics material containing food.

Although the following description relates exclusively to the manufacture of carton sleeves for containing such trays, it is the intention of the inventor that cartons according to the invention will have a much wider field of application. Specifically, it will be immediately understood by those skilled in the art that the cartons hereinafter described and the method of manufacturing same will have radical implications on the way carton manufacture is currently conducted. Furthermore, the cartons provided by the invention need not necessary encase plastic, food carrying trays but any particular tray or insert may be considered.

The term carton as used hereinafter refers in general to a cardboard or other similar flexible and formable material which has been stamped to form a blank pre-creased and cut in desired locations which is subsequently folded and glued in a predetermined manner to form an erected construction having an interior. The term tray shall be used to describe that which is inserted or may be received in the interior of the carton. Such cartons and trays are well known in the art and further discussion is therefore not necessary.

Sleeve type cartons, being those which have at least one end open and are adapted to receive a tray which is slid into the interior of the carton through the open end thereof, are currently provided in very great numbers to foodstuff manufacturers and producers and supermarket chains for encasing the trays in which foodstuffs are deposited. Examples of foodstuffs deposited in such trays include microwave meals such as curries, Chinese dishes, lasagnes, snacks, etc. The convenience to the user of so providing such foods is that the tray and sleeve carton can simply be discarded after the foodstuff has been cooked without any requirement to use or dirty cooking pots, pans and the like.

The sleeve carton has additional advantages in that such sleeves can be easily printed with cooking instructions, promotional offers, price labels, and general information concerning the product contained in the tray which it surrounds. Such sleeve cartons are relatively inexpensive to produce, the most significant cost of construction being the cost of the board from which they are manufactured.

The most common, simple and therefore current construction method of such cartons involves the stamping of pre-creased and pre-cut blanks from sheets of board, whereafter adhesive is applied to a flap at one end of the flat blank which is folded over the body of the blank and brought into contact with the opposite edge. The folding operation may either be conducted with a tray suitably positioned on what becomes the inner surface of the blank after folding, the flaps of the blank on either side of the tray being folded therearound and subsequently glued in position, or alternatively the blank may be formed into a sleeve type carton entirely separately from the tray. In the latter case, the formed cartons are usually transported in flattened form to the erection site where machinery urges opposite edges of the carton together to erect same. The erection process forms the flattened blank into a sleeve into which the tray may be slid from one or other of the open ends of the sleeve. Accordingly such cartoons are often termed"end-load" cartons. This invention is primarily concerned with end-load cartons.

The fundamental disadvantages of such cartons are firstly that an unnecessary quantity of board is used in their construction, and secondly they are structurally weak and lack rigidity. To elaborate, the sleeves are generally of rectangular configuration and their method of construction is such that the only region of the carton having two thicknesses of board is that region where opposite edges of the blank are glued to one another after being folded. This region is usually disposed along the base of the carton, and therefore the remaining surfaces of the carton, especially the side walls, being only of a single thickness of board are weak and flimsy.

Furthermore, any cut and creased carton blank will have a tendency to elastically recover once formed into a carton, and the nature of the creases provided in conventional blanks are such that elastic recovery is unsymmetrical about the longitudinal axis of the carton, i. e. that axis along which a tray is slid into the carton. The carton tends to collapse and tries to resume its originally flat condition by becoming skewed about the said longitudinal axis. Accordingly the carton lacks an aesthetic appearance without a tray inserted therein, and the side walls lack any support along a transverse axis of the carton.

During the formation of the carton from the blank, at least one surface of the blank must be adequately held while another portion must be capable of being rotated about one of the crease lines until a pair of opposite edges of the carton are brought into overlapping contact whereupon they are adhered to one another. The requirement for adequate purchase on respective blank portions to deform same into the carton shape is such that these portions are generally complete panels and therefore an excess quantity of board is used in the carton construction. Although a complete sleeve can be printed with information concerning the product contained in the tray, cooking instructions and the like, such information could easily be printed on only one surface of the carton in condensed form. There is no requirement whatsoever to provide a complete sleeve.

It is the object of the invention to provide a sleeve-type carton and method of manufacturing same which provides improved structural rigidity in a transverse direction for the carton, and which can also significantly reduce the quantity of board required in the manufacture of such cartons.

It is a further object of the invention to provide a method of carton manufacture which is simpler and more efficient than conventional methods.

According to the invention there is provided a method of manufacturing a carton from a pre-cut blank having a width and a length and having edges, said blank having at least one cut line generally in a width direction between the edges but within said edges and defining first and second portions on either side of said cut line, comprising the steps of folding the first portion about an axis proximate or coincidental and substantially parallel with said cut line, adhering the first portion to the second portion only in regions proximate the edges thereof, and urging the adhered edges together in the width direction to separate the first and second portions from one another in their central regions thus defining a cavity therebetween which can receive and retain a tray or the like.

Preferably the blank is provided with a plurality of crease lines which facilitate the folding operations, and also constrain the first and second portions to separate when their respective edges are urged together.

Preferably the carton blank is provided with a first and second cut lines in the width direction but spaced in the length direction which define first, second and third portions of the blank, the second portion being defined between the two cut lines, and the method additionally including the steps of folding the third portion about an axis proximate or coincidental and substantially parallel with said second cut line, adhering the third portion to the second portion only in regions proximate the edges thereof, and urging the adhered edges together to separate the first and third portions from the second portion in their central regions thus defining a cavity therebetween which can receive and retain a tray or the like. In this embodiment the second portion preferably constitutes the uppermost cover portion of the carton, whereas the first and third portions are in the form of straps behind said second portion which retain the tray in the carton.

Preferably the blank is provided with a pair of crease lines in the second portion in a length direction proximate the edges of the said blank which define side wall portions with said edges, said crease lines being substantially perpendicular to the cut line or lines, and wherein the separation of the crease lines is less than the width of the cut line or lines, and the first, second and optionally third portions are adhered to one another in at least regions beyond the cut lines in the width direction.

Further preferably, further fold lines substantially parallel with the fold lines in the second portion are provided in the first and optionally the third portions, said further fold lines being closer to the edges of the blank than the respective fold lines in the second portion such that after folding and adhering said first and optionally third portions to said second portion, said first and third portions automatically separate from the first portion when the edges are urged together.

According to a second aspect of the invention there is provided a pre-cut blank having a width and a length and having edges, said blank having at least one cut line generally in a width direction between the edges but within said edges and defining first and second portions on either side of said cut line such that the first portion can be folded about an axis proximate or coincidental and substantially parallel with said cut line, and can be adhered to the second portion only in regions proximate the edges thereof, with subsequent urging together of the adhered edges separating the first and second portions from one another in their central regions thus defining a cavity therebetween which can receive and retain a tray or the like.

Henceforth, an inherently simple sleeve-type carton construction results but which has far greater structural rigidity in the width or transverse direction because the act of folding the first and second portions together and adhering same effectively doubles the board thickness of the side walls of the carton where said portions are adhered.

A further advantage is the completely symmetrical carton construction which results. Although the carton will still have a tendency to collapse when the tray encased thereby is slid from within the carton, such collapse occurs symmetrically as the side walls simply expand outwardly pulling the first and optionally third portions back towards the second portion from which they were separated when the edges were urged together.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying diagrammatic figures wherein: Figure 1 shows a plan view of a blank according to the invention, Figure 2 shows the first stage in the construction method according to the invention, and Figure 3 shows a perspective view of the completed carton.

Referring firstly to Figure 1 there is shown a pre-cut and creased cardboard blank 2. Crease lines are shown by dotted lines whereas cuts are shown by solid lines.

The blank is defined by long edges 4,6, and short edges 8,10 parallel to the length and width of the blank respectively. Cut lines 12,14 together with crease lines 13,15, define a first portion 16 of the blank between the first short edge 8, a second portion 18 of the blank between each of said cut and crease lines, and a third portion 20 with the second short edge respectively.

Further cut lines 22,24,26,28 define lug portions 30,32,34,36 with the short edges 8,10 and the long edges 4,6. The distance of the tip of the lug portions from the respective long edges by which they are partially defined is fractionally less that the distance between the long edges 4,6 and crease lines 38,40 provided along the length of the blank in the second portion 18. The reason for this will become apparent with reference to Figure 3.

Additional crease lines 42,44,46,48 are provided in the first and third portions 16,20, respectively, and additional crease lines 13' and 15'are also provided in the said first and third portions in perpendicular relationship to the crease lines 13,15.

Referring now to Figure 2, the carton is shown with first and third portions 16,20 folded about the cut line 12 and crease lines 13, and cut line 14 and crease lines 15 respectively. The nature of the cut lines 12,14 provides two pairs of edges 12', 12", and 14', 14", the edges 12', 14'forming lips 41,43 which are ideally the same shape as the tray which the carton erected from the blank 2 is adapted to contain. Alternatively, the lips 41,43 can be any desired shape without alteration of the rectangular shape of the original blank.

This constitutes a major advantage of the invention.

The lug portions 30,32,34,36, and optionally areas 45,47,49,51 of the first and third portions are adhered to corresponding areas on the second portion 18. It is to be noted that the tips of the lug portions are disposed without the crease lines 38,40 and thus do not present any hindrance to the urging together of the long edges and folding thereof about said crease lines which gives rise to the carton shape shown in Figure 3 (the carton of this figure is actually shown upside down for the purposes of clarity).

In Figure 2, it can also be seen that the crease lines 13'and the crease lines 42,44 of the first portion 16 are disposed on either side of the crease lines 38,40 of the second portion 18. The same is true of crease lines 15', and of crease lines 46,48 in respect of the third portion 20. All these crease lines are also parallel, and accordingly when side panel sections 60,62 of the second portion 18 are folded inwardly thereof as indicated by arrows 64,66 in Figure 3, the first and third portions 16,20 automatically separate from and rise above the second portion 18. Henceforth a sleeve-type carton construction is provided.

It is to be mentioned that the dimension of the first and third portions 16, 20 may be chosen such that their edges are contiguous after folding such that a complete sleeve is formed as opposed to the strap-like construction shown in Figure 3, or alternatively only one of the first and third portions may be provided of similar dimensions such that after folding of said portion onto the second portion and subsequent erection of the carton, a complete sleevetype carton is provided.

It can also be seen from figure 3 that the crease lines 38,13', 42,44 and 40 all form corners of the panels of the carton which are formed as a result of the erection thereof. Furthermore, because the lug portions 30,32,34,36, and the areas 45,47,49,51 of the first and third portions 16,20 are firmly adhered to the side walls 60,62 of the second portion 18, the carton is provided as a whole with greater rigidity in its transverse (width) direction.

Perhaps most importantly, the rectangular starting shape of the blank in Figure 1 should be noted. Rectangular blank shapes are highly economical because there is little or no board wastage when such blanks are cut from sheets of board material.

The fact that the first and third portions 16, 20 are set inwardly of the second portion 18 allows for easier access to the underside of a tray held within the carton, as opposed to conventional sleeve-type cartons whose upper and lower portions are commonly of identical dimension.

Claims

CLAIMS 1. A method of manufacturing a carton from a blank having a width and a length and having edges, said blank having at least one cut line generally in a width direction between the edges but within said edges and defining first and second portions on either side of said cut line, comprising the steps of folding the first portion about an axis proximate or coincidental and substantially parallel with said cut line, adhering the first portion to the second portion only in regions proximate the edges thereof, and urging the adhered edges together in the width direction to separate the first and second portions from one another in their central regions thus defining a cavity therebetween which can receive and retain a tray or the like.
2. A method according to claim 1 wherein the blank is provided with a plurality of crease lines parallel to the edges between which said cut is made to facilitate the folding operations.
3. A method according to claim 1 or 2 wherein the fold lines are provided to constrain the first and second portions to separate when respective opposite edges are urged together.
4. A method according to any preceding claim characterised in that the carton blank is provided with a first and second cut lines in the width direction but spaced in the length direction which define first, second and third portions of the blank, the second portion being defined between the two cut lines, and the method additionally including the steps of folding the third portion about an axis proximate or coincidental and substantially parallel with said second cut line, adhering the third portion to the second portion only in regions proximate the edges thereof, and urging the adhered edges together to separate the first and third portions from the second portion in their central regions thus defining a cavity therebetween which can receive and retain a tray or the like.
5. A method according to claim 4 wherein the second portion constitutes the uppermost cover portion of the carton, the first and third portions being in the form of straps behind said second portion which retain the tray in the carton.
6. A method according to any of the preceding claims wherein the blank is provided with a pair of crease lines in the second portion in a length direction proximate the edges of the said blank which define side wall portions with said edges, said crease lines being substantially perpendicular to the cut line or lines, and wherein the separation of the crease lines is less than the width of the cut line or lines, and the first, second and optionally third portions are adhered to one another in at least regions beyond the cut lines in the width direction.
7. A method according to claim 6 wherein further fold lines substantially parallel with the fold lines in the second portion are provided in the first and optionally the third portions, said further fold lines being closer to the edges of the blank than the respective fold lines in the second portion such that after folding and adhering said first and optionally third portions to said second portion, said first and third portions automatically separate from the first portion when the edges are urged together.
8. A blank having a width and a length and having edges, said blank having at least one cut line generally in a width direction between the edges but within said edges and defining first and second portions on either side of said cut line such that the first portion can be folded about an axis proximate or coincidental and substantially parallel with said cut line, and can be adhered to the second portion only in regions proximate the edges thereof, with subsequent urging together of the adhered edges separating the first and second portions from one another in their central regions thus defining a cavity therebetween which can receive and retain a tray or the like.
9. A blank according to claim 8 having the features mentioned in any one of claims 1-7.
10. A method substantially as hereinbefore described with reference to the accompanying drawings.
11. A blank substantially as hereinbefore described with reference to the accompanying drawings.