A food-carrying cardboard tray

Abstract

 The tray has a bottom (12) and a peripheral wall (14), with a substantially rectangular overhanging ledge (16) extending from the edge of the wall. The ledge (16) has reinforcing flaps (18, 20) which are folded over and glued onto one of its sides and which extend along at least two opposite sides of the ledge.

Description

[0001] This invention relates to a food-carrying cardboard tray.

[0002] It is widely known to package foods such as meat, vegetables, fruits, etc. in cardboard trays having a peripheral, overhanging ledge on which a printed cover is usually glued. Such trays are manufactured from a die-cut cardboard sheet, which is subsequently thermoformed in a die into a desired hollow shape having a peripheral ledge.

[0003] A drawback of the above trays is that they have a low stiffness to lateral compression, so that they are readily misshapen during transport, handling or storing on shelves and benches when offered on sale.

[0004] Moreover, automatic packaging machines are widely used for the on-site packaging of fresh foods, typically in markets and supermarkets, which machines are arranged for operating with trays of a stiff material such as polyethylene or the like, and are capable of wrapping a protective film onto the trays as they are filled up by the staff.

[0005] Although it would be desirable to use the above packaging machines also with cardboard trays, the latter are unsuitable for such use because they, due to the above-mentioned low lateral stiffness, tend to be deformed by the tension of the wrapping film.

[0006] In order to overcome the above drawback, it has been proposed (see, e.g., WO 02/060768) to glue a reinforcing cardboard ring onto the ledge of the tray. However, the manufacture of such rings involves a considerable waste of material, because the portion of material inside the ring is lost as irrecoverable scrap.

[0007] Moreover, aligning the ring onto the tray ledge during the gluing step is a complex operation that is difficult to be implemented on conventional processing lines used for manufacturing cardboard trays.

[0008] It is therefore a main object of the invention to provide a cardboard tray for holding foods, which has a high lateral stiffness while being easier and cheaper to manufacture than known trays having an applied reinforcement ring.

[0009] Another object of the invention is to provide a tray that can be manufactured on conventional production lines, by adopting operations that are simple and easily automated in the usual tray-manufacturing processes.

[0010] The above and other objects and advantages, such as will become better apparent hereinafter, are achieved by a cardboard tray for foods having the features recited in claim 1, while the subordinate claims define other advantageous though secondary features.

[0011] The invention is described below in greater detail with reference to a few preferred though non-exclusive embodiments, which are illustrated by way of non-limitative example in the accompanying drawings, wherein:

Figure 1 is a perspective view of a cardboard tray for foodstuffs according to the invention;

Figure 2 is plan view of a cardboard blank used for making the tray of Fig. 1;

Figure 3 is a view of a detail of the tray of Fig.1, in a cross-section made along line III-III;

Figure 4 is a cross-sectional view similar to Fig. 3, showing a first alternate embodiment of the tray according to the invention;

Figure 5 is a view showing a portion of the tray blank in plan view, according to a second alternate embodiment of the invention;

Figure 6 is a cross-sectional view similar to Figs. 3 and 4, showing a third alternate embodiment of the tray according to the invention;

Figure 7 is a cross-sectional view similar to Fig. 5, showing a fourth alternate embodiment of the tray according to the invention.

[0012] With reference to Figs. 1 and 2, a cardboard tray 10 has a flat bottom 12 and a peripheral wall 14, whose upper edge extends to form an overhanging ledge 16.

[0013] Flat bottom 12 has a substantially rectangular shape with rounded corners. Peripheral wall 14 comprises two major side walls 14a and two minor side walls 14b, which are connected by corrugated corner walls 14c located at the rounded corners of bottom 12. Ledge 16 extends continuously along the edge of the peripheral wall 14, and it accordingly comprises straight portions such as 16a, 16b adjacent side walls 14a, 14b, and curved portions such as 16c adjacent corner walls 14c. The corrugations made on corner walls 14c also extend to curved portions 16c of ledge 16.

[0014] According to the invention, ledge 16 has reinforcing side flaps 18, 20 and reinforcing corner flaps 22 that are folded and glued to the underside of the ledge. More particularly, reinforcing side flaps 18, 20 respectively extend along the straight portions 16a, 16b of the ledge, while reinforcing corner flaps 22 extend along the curved portions 16c and are also corrugated so that they accompany the rounded profile of the ledge.

[0015] With reference to Fig. 2, a tray according to the invention is made from a cardboard sheet 24 that has been dinked or die-cut in a substantially rectangular shape with rounded corners 26. The dotted lines on Fig. 2 indicate the lines along which the sheet will be folded in order to form the tray. At the junction points between the sides and the rounded corners of the sheet, notches such as 28 are cut to define side strips such as 30, 32 and corner strips such as 34, which are respectively intended to provide the reinforcing side flaps and the reinforcing corner flaps for the tray.

[0016] Sheet 24 is thermoformed in a mould so that it acquires the desired hollow shape of tray 10. More particularly, the tray bottom 12 comprises a central portion of the sheet that is bounded by dotted line L1 shown on Fig. 2; the peripheral wall comprises an intermediate band of the sheet that is bounded externally by dotted line L2; the ledge 16 comprises an outer band on the sheet, which is bounded by dotted line L3. Side strips 30, 32 and corner strips 34 are designed to be folded and glued to provide the above reinforcing flaps 18, 20 and 22.

[0017] According to a first alternate embodiment of the invention, shown on Fig. 4, the reinforcing side flaps such as 118 and the reinforcing corner flaps (not shown) are folded and glued onto the upper side of the ledge.

[0018] In a second alternate embodiment of the invention, of whose blank a plan view is shown on Fig. 5, the rounded corners of the cardboard sheet are provided with a number of notches such as 228, which give rise to several side-by-side corner strips such as 234. Thereby, several side-by-side reinforcing corner flaps are formed rather than a single flap. It should be understood that in this case, too, the flaps may be folded and glued either onto the upper or the under side of the ledge.

[0019] The main advantage of the second embodiment is that it reduces deformations and stresses in the cardboard corner flaps. This reduction may be necessary or not, depending on the characteristics of the specific cardboard used.

[0020] In a third alternate embodiment of the invention, shown on Fig. 6, the reinforcing side flaps 318 and the reinforcing corner flaps are folded onto the underside of the ledge and extend further along the outside surface of the peripheral wall of the tray.

[0021] In a fourth alternate embodiment of the invention, shown on Fig. 7, the reinforcing side flaps 418 and the reinforcing corner flaps are folded onto the upper side of the ledge and extend further along the inside surface of the peripheral wall of the tray.

[0022] A few preferred embodiments of the invention have been described, but it should be understood that a person skilled in the art might make a number of changes to them within the same inventive concept. For instance, although the Figures show a rectangular tray, which is most commonly used, it should be understood that the principles of the invention could be applied to other polygonal and even circular trays, particularly in the case of the third and fourth embodiment. Also, the reinforcing flaps might be provided only along limited portions of the periphery of the tray wall. For instance, in a rectangular tray with rounded corners, only the straight sides of the tray, or even only one pair of opposite straight sides, might carry reinforcing flaps, thereby avoiding curved reinforcing corner flaps: while this would provide a lower degree of stiffness, it might be adequate in certain applications or with certain kinds of cardboard. Also, with reference to the third and fourth alternate embodiments described, the reinforcing side flaps might extend only over a fraction of the side wall of the tray rather than down to its bottom as shown in the Figures.

Claims

1. A food-carrying cardboard tray (10) comprising a substantially flat bottom (12) and a peripheral wall (14) upwardly extending integrally from the periphery of the bottom, and an integral, overhanging ledge (16) extending from the upper edge of the wall, characterized in that the ledge (16) has reinforcing flaps (18, 20) that are folded over and glued onto one of its sides and extend along at least parts of the ledge.

2. The tray of claim 1, characterized in that said reinforcing flaps (18) are folded onto the underside of the ledge (16).

3. The tray of claim 1, characterized in that said reinforcing flaps (18) are folded onto the upper side of the ledge (16).

4. The tray of any of claims 1 to 3, characterized in that said reinforcing flaps (318) are folded onto the underside of the ledge and extend for at least a portion of the outer surface of the peripheral wall of the tray.

5. The tray of any of claims 1 to 4, characterized in that said reinforcing flaps (418) are folded onto the upper side of the ledge and extend for at least a portion of the inner surface of the peripheral wall of the tray.

6. The tray of any of claims 1 to 5, wherein said ledge comprises curved portions (16c), characterized in that the ledge (16) has reinforcing flaps (22) that are folded and glued onto one of its sides also along said curved portions (16c).

7. The tray of claim 6, characterized in that said curved portions (16c) of the reinforcing flaps (22) are cut with notches (228) at intervals and substantially at right angles to the peripheral direction of the ledge.

Drawing