TRAY-LIKE PACKAGING UNIT AND A METHOD FOR ERECTING A PACKAGING UNIT

Abstract: The present invention relates to a tray-like packaging unit for cylindrical goods, such as cans for drinks or other substances. The tray-like packaging unit is formed from a blank of corrugated fibreboard, which in the erected state comprises a flat bottom and transversely to the bottom, opposing short and long sides, respectively, which are affixed to each other. The object of the tray-like packaging unit of the above-mentioned type is to keep together several pieces of goods to form a handy unit and at the same time to expose the goods to be identified by a customer. The tray-like packaging unit is characterised in that the corrugated fibreboard in the tray-like packaging unit is a micro single wall and that the corners between the short and long sides are oblique and form corner sides, supporting the goods in the tray-like packaging unit. The invention also relates to a method for erecting a tray-like packaging unit of corrugated fibreboard.

Description: TRAY-LIKE PACKAGING UNIT AND A METHOD FOR ERECTING A PACKAGING UNIT Field of the invention The present invention relates to a tray-like packaging unit for cylindrical goods, such as cans for drinks or other substances. The tray- like packaging unit is formed from a blank of corrugated fibre- board, which in the erected state comprises a bottom and, transversely to the bottom, opposing short and long sides, respectively. Tray- like packaging units of the aforedescribed type are intended to form units for keeping together a suitable number of pieces of goods to form a handy unit for carrying the goods and for exposing the goods such that a customer may identify the individual piece of goods in the tray-like packaging unit. The invention also relates to a method for erecting a tray-like packaging unit for cylindrical goods from a blank of corrugated fibreboard. Background of the invention Drinks, such as for example beer, are portioned out into packages, such as cans or bottles, having standardised exterior size, particularly a standardised cylinder diameter. The diameter has been adapted to fit the dimensions of standardised pallets, such as for example a Euro pallet having a loading area of 800x1200 mm. The goods, i.e. the cans or bottles, have been dimensioned in order to fit on a loading area of a standardised pallet, such that the packages, side by side, precisely cover the loading area of the pallet. This type of goods are handled in large quantities by producers, distributors as well as in the markets. Several packages, such as cans, are difficult to handle together due to the cylindrical form, the slippery surface of the tin material in the cans and the weight of the liquid-filled packages. The filled packages tend to fall over or tip easily. In order to be able to handle several packages together more easily, they are kept together in tray-like packaging units, forming units which carries several packages, e.g. 4 x 6 packages. The tray-like packaging unit comprises a bottom, where the pieces of goods are being placed side by side, and long sides and short sides directed upwards and extending up to about half the height of the package, such that the upper parts of the packages are exposed. The long sides and the short sides are attached to each other by means of flaps forming extensions of the end parts of the short sides or the long sides. The flaps are glued against the inside of adjacent long side or short side forming perpendicular corners. The material in the tray- like packaging units must have sufficient rigidity and strength to give the tray the stability that is required to provide sufficient support to the relatively heavy and recalcitrant goods. Conventionally, corrugated fibreboard is used for tray-like packaging units. In order to achieve sufficient rigidity and strength in the packaging units, corrugated fibreboard of the type fine singe wall, designated fine single wall B according to Swedish Standard, or medium single wall, designated medium single wall C, is used. The single wall, and thus the present fine single wall or medium single wall, is made of a fluting between liners, which are glued to the fluting on each side thereof. The corrugated fibreboard, in the form of fine single wall or medium single wall, has a thickness of about 3-4 mm (Swedish Standard SS 843001) and a fluting having a compactness of about 150 wavelengths per meter (SIS 843003) in the case of a fine single wall and about 130 wavelengths per meter (SIS 843003) in the case of a medium single wall. When goods of the above-mentioned type are stored and distributed, they are kept together in the tray-like packaging units. These units are stacked on standardised pallets, side by side up against each other, and are piled on top of each other on the pallet. When several tray- like packaging units are placed up against each other, side by side on a pallet in this manner, the thickness of the material of the sides of the tray-like packaging units and also deviations created at the erection of the blank have an effect on the outer dimensions of the load package on the pallet to such an extent that an overhang is formed outside the loading area of the pallet. As described above, the diameter of the cans or packages are defined in order to fit the size of the pallet, without considering the fact that several tray-like packaging units are to be accommodated between the cans on the pallet. On a pallet having a loading area of 800 x 1200 mm, the load package is thus enlarged to the ex- terior dimensions of 816 x 1220 mm. When the pallet with its load are handled or lifted, the overhang outside the loading area of the pallet may cause damages to the load or accidents. Incidents, such as cans falling down and loads tipping over, are frequent in breweries, store rooms and shopping centres. Such in- cidents lead to an unsafe situation for the staff and to cassations of goods. The overhang outside a pallet may accidentally be pushed or lifted and when a pallet, placed close to an adjacent pallet with an overhang, is lifted it may grab the overhang such that the load is tipping over. The basic idea of the invention The object of the present invention is to overcome the above problems by providing a tray-like packaging unit having the stability and strength which is required in order to provide sufficient support for the goods in the tray and which can be stacked on a standardised pallet in a secure manner, i.e. a formation of dangerous overhang outside the loading area of the pallet is avoided. In accordance with the invention, this object is achieved in a tray- like packaging unit of the aforedescribed type and having the characte- rising features as set forth in the claims. According the invention, a thin corrugated fibreboard of the type micro single wall is being used as material for the tray-like packaging unit. In spite of the thin material, the tray-like packaging unit according to the invention has sufficient strength and stability. This is due to the constructional features of the tray, which is able to withstand the lateral forces from the goods in the tray. The thin micro single wall material is advantageous in that the measurement accuracy in the folding of the tray in the erection machine is high, as will be explained more in detail below. The measurement accuracy implies that a tightening "belt effect" on the goods in the tray is achieved during the erection and joining of the sides of the tray. This effect is achieved in that external pressing forces are acting on the sides of the tray and the goods inside during erection and especially during joining of the sides of the tray-like packaging unit. In the tray-like packaging unit according to the invention, lateral forces from the goods are minimised compared to a conventional tray-like packaging unit and the remaining lateral forces efficiently can be taken up by the sides of the tray-like packaging unit according to the invention. The tray-like packaging unit according to the invention thus has the required strength and stability which is achieved by its constructive features. The thin material and the accuracy in dimensions in the tray according to the invention imply that a standardised pallet may be stacked as described above such that no overhang, which is troublesome and risky and may cause damages and cassations, is formed outside the loading area of the- pallet. The micro single wall material according to the invention is a single wall, like the fine single wall and the medium single wall, and is formed by a central fluting with liners glued on each side thereof. Contrary to the fine single wall and the medium single wall, the micro single wall is thin, having a thickness of just 1 mm. The micro single wall has a flute profile F that is very compact and has about 420 flute lengths per meter, which positively contributes to the rigidity of the material. In accordance with a preferred embodiment of the invention, the micro single wall has a flexural rigidity exceeding about 2200 mN/5cm and which is preferably about 2530-2540 mN/5cm and specifically about 2535 mN/5cm (according to method SCAN:P6490). In accordance with a further embodiment of the invention, the tray-like packaging unit is formed from a blank having outer edge lines which together with the extensions of the outer edge lines form a rec- tangular basic form. Tray-like packaging units are manufactured and used in great numbers and it is therefore economically essential to design the blank such that the consumption of material is minimised. Short description of the drawings The invention will now be described in more detail with reference to the accompanying drawings, in which Figures 1 - 4 illustrate a tray-like packaging unit according to prior art and Figures 5 - 9 illustrate two different embodiments of the invention. Figure 1 illustrates diagrammatically a tray-like packaging unit according to prior art. Figure 2 illustrates diagrammatically a cross-sectional view of a piece of the corrugated fibreboard material in the tray-like packaging unit of Figure 1. Figure 3 illustrates diagrammatically a plan view of the tray-like packaging unit of Figure 1 carrying goods. Figure 4 illustrates diagrammatically a number of tray-like packaging units according to prior art, stacked on a standardised pallet. Figure 5 shows the blank for a tray-like packaging unit according to the invention. Figure 6 shows a tray-like packaging unit according to the invention, which is erected from the blank of Figure 5. Figure 7 shows a cross-sectional view of a piece of the corrugated fibreboard material in the tray-like packaging unit according to the invention. Figure 8 shows, in the same way as in Figure 3, a plan view of a tray-like packaging unit according to the invention carrying goods. Figure 9 shows the blank of a tray-like packaging unit in accordance with an alternative embodiment of the invention. Detailed description of embodiments of the invention Figures 1 - 4 illustrate how cylindrical goods, such as for example cans for beer, are stored in accordance with conventional prior art. A tray-like packaging unit 2, as shown in Fig. 1 , is used for keeping together several pieces of goods, e.g. 4 x 6, to form a handy unit. The tray-like packaging unit 2 comprises a rectangular bottom 4 and, dir- ected upwards, opposing short sides 6 and long sides 8, respectively. The end parts of the long sides 8 have extension flaps 10, which are being folded to bear on and be affixed to the inside of adjacent short side 6 to form perpendicular corners. Figure 2 shows a cross-sectional view through a part of the cor- rugated fibreboard material in the tray-like packaging unit of Fig. 1. The material is a corrugated fibreboard of the type medium single wall, alternatively fine single wall. The medium single wall has a thickness h of about 4 mm and is made of a central corrugated fluting 12 with glued liners 14 on each side thereof. The blank comprises folding lines 16 positioned accurately in order to form edge lines in the erected tray-like packaging unit 2. However, when the blank is erected, the actual folding does not always occur in the marked folding line 16. The folding thus instead occurs in an adjacent position, where the corrugation permits folding, i.e. in a through of the flute 17. When medium single wall ma- terial is used, as in the prior art, a deviation from the optimal dimen- sions, in the dimensions of the erected tray, which is not negligible, is hereby created. Figure 3 shows a plan view of the tray-like packaging unit 2 according to the prior art, carrying several cylindrical goods 18, such as beer cans. The extension flaps 10 bear on and are glued against the short side 6 and form an opening 11 between the flaps 10 on the inside of the tray. The sides of the tray-like packaging unit according to the prior art, thus have a thickness varying between the dimension h, i.e. about 4 mm, and 2h, i.e. about 8 mm. Figure 4 shows schematically how the tray-like packaging units 2 according to the prior art are carrying goods and are stacked on the loading area 28 of a standardised pallet 22. The load package 24 formed thereby has exterior dimensions exceeding the loading area 28 of the pallet, which implies that parts of the load package 24 form overhang 26 outside the loading area 28. In order to illustrate the problem behind the present invention, the overhang 26 in Fig. 4 is shown enlarged. The overhang 26 in the prior art is caused partly by the total material thickness of the sides of the tray-like packaging units which are placed side by side and partly by deviations from the defined dimen- sions ensuing from folding the blank when the tray is erected, as described above in connection with Fig. 2. The corrugated fibreboard material in the tray-like packaging unit according to the prior art, i.e. the fine single wall or the medium single wall, has been selected and is required in order to achieve sufficient stability and strength in the prior art tray-like packaging unit. In the design of the prior art tray-like packaging unit, in which supporting surfaces are lacking in some parts of the tray, such as in the open corners and at the openings 11 , at the slightest lack of balance or some other influence on the tray, movements between the slippery cans 18 arises, such that the tray is affect- ed and the effect of keeping the goods together is deteriorated. The tray- like packaging unit of the prior art, primarily has the function to carry the goods, while it lacks the function to keep the goods together, which is one object of the present invention. In Figures 5 - 8 an embodiment of a tray-like packaging unit according to the present invention is shown. Fig. 5 shows a blank 30 for a tray-like packaging unit 32, which is shown in its erected state in Fig. 6. The tray-like packaging unit 32 comprises an octagonal bottom 34 and opposing short sides 36, long sides 38 and corner sides 39, directed upwards in the erected state. Corner sides 39 constitute extensions of the end parts of the long sides 38 and the end parts of the corner sides are provided with extension flaps 40. The flaps are folded to bear on and to be affixed to, preferably by means of glue, the inside of the adjacent short side 36. Figure 7 shows a cross- sectional view of a part of the material of the blank 30. The material in the tray-like packaging unit according to the invention is a corrugated fibreboard of a type designated micro single wall. The micro single wall is thin with a thickness of about 1 mm and comprises a fluting 42 and liners 44 glued on each side thereof. The fluting is formed with heat to a very compact corrugated layer, having standardised flute profile F of a board material having high rigidity. The flexural rigidity of the micro single wall should exceed about 2200 mN/5cm and is preferably about 2535 mN/5cm (according to method SCAN:P6490). The flexural rigidity may, however, fall below the stated limit value under special circumstances. Fig. 8 shows, in the same way as in Fig. 3, a plan view of the tray-like packaging unit 32 carrying several cylindrical pieces of goods 50, such as beer cans. The thin material in the tray-like packaging unit of the invention and especially in the flaps 40, implies that also the short sides 36 give support to the goods in the tray in the lateral direction. The oblique corner sides 39 give the outermost pieces of goods and thus all the goods in the tray-like packaging unit a considerably increased stability in the lateral direction. The pieces of goods which are placed in the corners are thus supported in three points. The goods in the tray-like packaging unit may further be grouped in groups of four or six pieces of goods, each group being enclosed by a fibreboard cover or fibreboard belt with open sides. An edge of the fibre- board cover for a group of goods, which is placed adjacent the corner of the tray-like packaging unit, coincides herewith conveniently with the folding line between the corner side and the long side or the short side, such that said edge is being "locked" in the folding. In this way the fibreboard cover and thus the whole group of goods is fixed in the tray- like packaging unit. Fig. 9 shows an alternative embodiment of a blank for the tray-like packaging unit of the invention. The blank 52 comprises an octagonal bottom 54, opposing long and short sides 56, 58, respectively, and extension flaps 60 forming oblique corner sides in the erected tray. Each long and short side 56, 58, respectively, has extension flaps 60 in each end part, forming overlapping and mutually glued corner sides in the erected state of the tray-like packaging unit. In this embodiment of the erected tray-like packaging unit, there is thus no equivalent to the opening 11 , which is formed according to the prior art and is shown specifically in Figure 3. The tray-like packaging unit is erected from a blank in a erecting machine, after the goods have been placed on the bottom. The erecting is taking place by folding up the sides around the goods, such that they are enclosed by the sides and subsequently the extension flaps are affixed against the insides of the short or long sides to join the sides to each other. At the same time as the sides of the tray-like packaging unit are joined together, external pressing forces are applied, preferably in a specific pressing station, against the sides and the goods, in order to press these together during the joining process, e.g. by gluing. The extension flaps are fastened against the insides of the short or long sides, such that a tightening effect, a "belt effect", is achieved, in order to keep the goods together in the tray-like packaging unit in a steady grip. By the combination of the selected material and the constructive features of the tray-like packaging unit of the invention, a tray is provided which is stable, strong and very efficiently keeps the goods together. Since the thickness of the material in the tray-like packaging unit of the invention is about V of the thickness of the material in the tray of the prior art, no overhang is formed outside the loading area of the pallet, when the tray-like packaging units are stacked side by side on the pallet, as described above. It will be understood that the invention is not restricted to the aforedescribed embodiments and that several modifications are conceivable within the scope of the claims. The extension flaps may, for example, be adapted to bear on the inside of the short sides and/ or the long sides of the tray-like packaging unit. The sides of the tray-like packaging unit may cover up to half and preferably less than half the height of the carried goods, such that these goods are exposed to the surrounding. The sides of the tray-like packaging unit may, however, within the scope of the invention, cover more than half the height of the goods and up to the whole height of the goods.

Claims: CLAIMS 1. A tray-like packaging unit for cylindrical goods, such as cans for drinks or other substances, said tray-like packaging unit (32) being formed from a blank (30; 52) of corrugated fibreboard, which in the erected state comprises a flat bottom (34; 53) and, transversely to the bottom, opposing short and long sides (36, 38; 58, 56), respectively, which are affixed to each other, characterised in that the corrugated fibreboard in the tray-like packaging unit is a micro single wall and that the corners between the short and long sides (36, 38; 58, 56) are oblique and form corner sides (39; 60), supporting the goods in the tray- like packaging unit. 2. A tray-like packaging unit according to claim 1 , characterised in that the sides (36, 38, 39; 58, 56, 60) are affixed to each other, such that they exert lateral forces against the goods (50) in the tray-like packaging unit. 3. A tray-like packaging unit according to claim 2, characterised in that the end parts of the corner sides (39) are provided with extension flaps (40), which bear on and are affixed to adjacent long or short side (36, 38). 4. A tray-like packaging unit according to claim 2, characterised in that the end parts of the long and/or short sides (56, 58) are provided with extension flaps (60) forming the oblique corner sides. 5. A tray-like packaging unit according to claim 4, characterised in that both end parts on each long and short side (56, 58) are provided with extension flaps (60) forming the oblique corner sides by overlapping, bearing on and being affixed to each other. 6. A tray-like packaging unit according to any of the preceding claims, characterised in that the blank (30, 52), forming the tray-like packaging unit (32) in the erected state, has outer edge lines, which together with extensions of the outer edge lines form an essentially rectangular basic form. 7. A tray-like packaging unit according to claim 6, characterised in that the long, short and corner sides (36, 38, 39) has a maximum height corresponding to half the height of the carried goods (50). 8. A tray-like packaging unit according to any of the preceding claims, characterised in that the flexural rigidity of the micro single wall exceeds about 2200 mN/5cm and is preferably about 2530 - 2540 mN/5cm. 9. A method of erecting a tray-like packaging unit for cylindrical goods, such as cans for drinks or other substances, from a blank of corrugated fibreboard, with a bottom (34; 54), on which the goods are placed prior to the erection and sides (36, 38, 39; 58, 56, 60) which are adapted to be folded around the goods (50) and then joined together, characterised in that the sides (36, 38, 39; 58, 56, 60) are joined together when external pressing forces are applied against the sides and the goods (50), in order to press them together during the joining process, such that the sides exert a pressure on the goods to keep them together.

Inventors: ABRAHAMSSON MIKAEL, KARLSSON KENNETH, ABRAHAMSSON, MIKAEL, KARLSSON, KENNETH
Applicants: ABRAHAMSSON MIKAEL, KARLSSON KENNETH, MUNKSJOE FOERPACKNINGAR, ABRAHAMSSON, MIKAEL, KARLSSON, KENNETH, MUNKSJOE FOERPACKNINGAR AB
Application year: 2001
Main classification: B65D5
IPC codes: B65D5