The present invention relates to a bowl formed by a tray closed by a sealing plastic film, a method for the production of such a tray and a blank and an apparatus used in such a method .

It is known producing such a tray by folding a cardboard or corrugated board blank in order to form a bottom panel and a side wall , and attaching the plastic sealing film on a rim protruding from the top edge of the side wall .

Such a bowl is thus formed by a maj or part of cardboard or corrugated board and a minor part of plastic material, which can be easily separated after use and thus sub jected to distinct recycling procedures with a substantially integral recovery of the initial raw materials .

One ob ject of the present invention is improving the known methods of production of the trays of such bowls , as well as the finally obtained trays .

According to the present invention, this obj ect is achieved by a monolithic blank comprising a main panel having a perimeter formed by a plurality of sides , wherein each side is provided of a respective flap consisting of an internal tab, a median panel and an external sub-flap, wherein a bottom panel is defined within the main panel by folding perimetric lines parallel to said sides , respectively, of the main panel , and wherein respective wings join at least some of said perimetric lines to a respective end part of the main panel which is adjacent to one of said sides , said end parts collectively forming a continuous rim completely surrounding said bottom panel .

Preferred features of the blank of the invention are disclosed in the claims dependent on claim 1 which follow .

In the absence of any specific indication to the contrary, any reference to "rectangular" in the present description and claims includes the particular case of " square" .

The blank of the present invention may be obtained by a die-cutting technique which guarantees absolute accuracy of the outer dimensions and allows to obtain any desired number of the sides of the perimeter of the blank .

A further sub ject-matter of the present invention is constituted by a method for the production of a tray from the above-disclosed monolithic blank, comprising the steps of :

- folding said internal tabs of 180 ° about the respective side, and fixing, in particular gluing said internal tabs to the respective end part s of the main panel,

- folding said median panels about the lines respectively parallel to said sides of the main panel, so as said median panels collectively form a side wall, - folding said external sub-flaps in respect of said side wall, so as said external sub-flaps are arranged in a plane parallel to the main panel, and

- detaching from the main panel said bottom panel and wings , and moving said bottom panel and wings away from said continuous rim, until a peripheral portion of the bottom panel is in contact with said external sub-flaps , and the wings are in contact with respective portions of the side wall adjacent to said external sub-flaps .

A further sub ject-matter of the present invention is constituted by another method for the production of a tray from the above-disclosed monolithic blank, by using an apparatus including a lower plate member having a central opening surrounded by a crown of through-holes , an upper member including an upper plate from which a ring-shaped relief protrudes downwards delimiting an internal volume, a punch movable through said central opening into said internal volume , and positioning pins each of which is respectively movable through one of said through-holes .

Preferred features of the methods of the invention are disclosed in the claims dependent on claim 6 and/or 8 , which follow .

The use of a single blank for producing the entire tray allows to meaningfully reduce the waste material , and thus the as sociated environmental impact and costs , in comparison with alternative techniques requiring to use two or more blanks .

A further sub ject-matter of the present invention is constituted by the tray obtainable by the above-disclosed methods , which can have any number of sides as desired .

The upper rim of the tray of the invention is fully continuous without any gap at all, so as it s production method does not need any step of sealing such gaps , and in any case guarantees the tightness of the sealing, even if a single blank is used for producing the entire tray .

The rim of the tray of the invention is very stif f , because it has a thicknes s which is twice the one of the blank and is integral with the side wall of the tray, and thus allows the adoption of high-speed sealing procedures for the application thereon of the plastic sealing film . Hence , the proces s time is meaningfully reduced .

A number as desired of the trays of the invention can be stacked, allowing a stacking distance between the rims of superposed trays as low as up to 3 mm .

The increased stiffness of the rim provides the additional advantage of allowing, if suitable, the use of the standard screw de-nesters which are conventionally used for handling the common plastics trays . Of course, even dedicated equipment may be used, if requested by the circumstances .

A further sub ject-matter of the present invention is constituted by a bowl comprising the above-disclosed tray which is closed by a plastic sealing film .

A further sub ject-matter of the present invention is constituted by an apparatus for the production of a tray from the above-disclosed monolithic blank, including a lower plate member having a central opening surrounded by a crown of through-holes , an upper member including an upper plate from which a ring-shaped relief protrudes downwards delimiting an internal volume , a punch movable through said central opening into said internal volume, and positioning pins each of which is respectively movable through one of said through-holes .

Further advantages and features of the present invention will be apparent from the following detailed description, given by way of non-limiting example with reference to the appended drawings , in which : figure 1 is a plan view of a blank according to the invention, figures 2 to 6 are respective perspective views of successive steps of a method according to the invention of erecting the blank of figure 1 into a tray, figure 7 is an exploded perspective view of a bowl obtainable by sealing with a plastic film the tray erected by the method of the invention illustrated by figures 2 to 6 , figure 8 is a plan view of a blank according to a further embodiment of the invention, figure 9 is a perspective view of a step of a further method according to the invention of erecting the blank of figure 8 into a tray, figure 10 is a cros s-section view according to line X- X of figure 9 , figures 11 , 12 and 13 are schematic cross-section views illustrating respective successive steps of the method of erecting the blank of figure 8 into a tray, and figure 14 is a perspective view illustrating a further step of the method of erecting the blank of figure 8 into a tray .

A monolithic cardboard or corrugated board blank comprises ( fig . 1 ) a rectangular main panel 10 having beveled corners 12 connecting two first parallel sides 14 to two second parallel sides 1 6 orthogonal to the first sides 14 . The blank is symmetric with regards to two orthogonal axes passing through the center of the main panel 10 and parallel to the first 14 and second 1 6 sides , respectively .

Each first and second side 14 , 16 and each beveled corner 12 is provided of a respective flap 18 consisting of an internal tab 20 , a median panel 22 and an external subflap 24 .

The internal tab 20 of each flap 18 of the first and second sides 14 , 1 6 is rectangular and shorter than the respective side . The median panel 22 of each flap 18 of the first and second sides 14 , 1 6 is trapezoidal and has a maj or basis , whose center portion is joined to the respective internal tab 20 by a first folding line 2 6, and a minor basis j oined to the respective external sub-flap 24 , which is trapezoidal, by a second folding line 28 .

The internal tab 20 of each flap 18 of the beveled corners 12 has a rectangular centre portion 30 and two inclined end portions 32. The median panel 22 of each flap 18 of the beveled corners 12 is trapezoidal and has a major basis, which is joined to the respective internal tab 20 by a third folding line 34, and a minor basis joined to the respective external sub-flap 24, which is trapezoidal, by a fourth folding line 36.

A rectangular bottom panel 38 having beveled corners is defined within the main panel 10 by perimetric folding lines 40, e.g. crease lines, respectively parallel to the first and second sides 14, 16 and beveled corners 12 of the main panel 10.

Respective trapezoidal wings 42 join each perimetric folding line 40 to a respective end part of the main panel 10 which is adjacent to one of said first and second sides 14, 16 and beveled corners 12. Each trapezoidal wing 42 is separated from each adjacent wing 42 by an opening 44 whose shape is substantially rhomboidal. The end parts of the main panel 10 collectively form a continuous rim 46 that completely surrounds the bottom panel 10 with the interposition of the wings 42 and the openings 44, and is joined to the wings 42 by pre-perforated detachment lines 48. A method for the production of a tray 50 from the above-disclosed blank comprises the initial step of folding (see arrows 52 in figure 2) the internal tabs 20 of 180° about the respective side 14, 16 or beveled corner 12 and fixing, in particular gluing them to the respective end parts of the main panel 10 forming the rim 46.

A successive step of the method provides (fig. 3) for folding the median panels 22 about the lines 26, 34 parallel to the first and second sides 14, 16 and beveled corners 12 of the main panel 10, respectively so as the median panels 22 collectively form an octagonal side wall, each face of which forms an angle lower than 90° with the bottom panel 38, e.g. in the range 65° to 85°, and is in contact with the adjacent faces.

Then, the external sub-flaps 24 are folded (see arrows 54) in respect of the side wall about lines 28, 36, respectively, so as they are arranged in a horizontal plane parallel to the main panel 10.

The thus formed intermediate product is turned upsidedown (fig. 4) , in order to facilitate detaching from the main panel 10 the bottom panel 38 and the trapezoidal wings 42 along the pre-perforated detachment lines 48. The bottom panel 38 and trapezoidal wings 42 are then moved orthogonally away (see arrow 56 in fig 5) from the continuous rim 46, until a peripheral portion of the bottom panel 38 is in contact with the folded external flaps 24, and the trapezoidal wings 42 are in contact with respective portions of the octagonal side wall adjacent to the external sub-flaps 24 (fig. 6) .

The strength of the base of the thus obtained tray 50 is increased by fixing, in particular gluing, the peripheral portion of the bottom panel 38 to the external sub-flaps 24, and the trapezoidal wings 42 to respective portions of the octagonal side wall adjacent to the external sub-flaps 24. On the other hand, the rim 46 , which is horizontal and parallel to the bottom panel 38 , constitutes an upper edge of the tray 50 without any gap which might bring about leaks during any succes sive sealing operation .

In this respect , it has also to be noticed that , since the internal tabs 20 collectively form a reinforcement of the continuous rim 46 , the thickness of this latter is doubled in respect of the one of the blank . Hence, a pile of nested trays 50 may be handled by screw de-nesters which are typically used for de-nesting conventional plastics trays , without requiring dedicated equipment . Of course , dedicated equipment may also be used for handling the trays 50 .

Finally, once the internal cavity of the tray 50 has been filled with the desired product s (not shown in the figures for the sake of clarity) , a plastic sealing film 58 ( fig . 7 ) is fixed thereon, e . g . by a glue line 60 applied on the upper face of the rim 4 6 . Hence, the film 58 closes the internal cavity of the tray 50 , and a final bowl is obtained .

After use , the cardboard tray 50 can be easily separated from the plastic film 58 , so that the initial raw materials can be substantially integrally recycled .

Figures 8 to 14 illustrate a further embodiment of a blank according to the invention and a method for the erection thereof into a tray, wherein features equal or equivalent to the ones disclosed with reference to the embodiment illustrated by the previous figures have the same reference number .

The only substantive difference of this latter blank from the one previously disclosed resides in that ( fig . 8 ) the trapezoidal wings 42 join only the perimetric folding lines 40 parallel to the first and second sides 14 , 1 6 to a respective end part of the main panel 10 which is adjacent to the first and second sides 14 , 1 6 . Each wing 42 is separated from each adj acent wing 42 by an opening 44 bordering the entire respective beveled corner 12 . As in the previous embodiment , the end part s of the main panel 10 collectively form a continuous rim 4 6 that completely surrounds the bottom panel 10 with the interposition of the wings 42 and the openings 44 , and is joined to the wings 42 by pre-perforated detachment lines 48 .

Additionally, reference number 61 indicates glue stripes in jected on the blank by conventional noz zles , when the blank is moved from a magazine to an apparatus for forming a tray therefrom . The illustrated positions of the glue stripes 61 are merely exemplificative and, as a matter of fact , their number and position can be freely selected .

In detail, a method for the production of a tray from the above-disclosed blank provides for using an apparatus including ( figures 9 and 10 ) a lower plate member 62 having a central opening 64 surrounded by a crown of circumferentially of fset through-holes 66, an upper member 68 including an upper plate 70 from which a ring-shaped relief 72 protrudes downwards delimiting an internal volume 74 , and a punch 7 6 movable through the central opening 64 into the internal volume 74 . The lower plate member 62 , the central opening 64 , the upper member 68 and the punch 7 6 are aligned along a central axis 80 orthogonal to the planes of the lower plate member 62 and the upper plate 70 .

Positioning pins 80 are movable through a respective through-hole 66, which is inwards inclined with regard to the central axis 80 .

The lower plate member 62 and the punch 7 6 are additionally provided of conventional vacuum devices (not illustrated in the figures for the sake of clarity) which guarantee , when desired, that the part s of the blank placed thereon remain stationary and safely adhered .

First of all, the glued blank is placed on an upper face of the lower plate member 62 in an arrangement which is symmetrical with regards to the central opening 64 and the central axis 80 . The upper member 68 is distanced from the lower plate member 62 during this initial step .

Then, the punch 76 is moved upwards in order to detach from the main panel 10 the bottom panel 38 and wings 42 , and move the bottom panel 38 and wings 42 away from the continuous rim 46 . Figures 9 and 10 illustrate the end configuration due to this movement of the punch 7 6 .

Successively, the pins 80 are moved upwards within the respective through-holes 66 in order to protrude from the lower plate member 62 and thus fold the flaps 18 about the respective first and second side 14 , 16 and beveled corner 12 ( fig . 11 ) . As a consequence, the flaps 18 face a lateral wall of the punch 7 6 and form a continuous side wall .

The upper member 68 is then moved downwards ( figures 12 and 13 ) and, due to the internal profile of the ringshaped relief 72 , forces parts of the blank against each other or the side wall of the punch 7 6 . Specifically, on one hand, the internal tabs 20 are folded of 180 ° about the respective side 14 , 16 or beveled corner 12 and fixed, in particular glued, to respective end part s of the main panel

10 , and, on the other hand, the sub-flaps 24 are folded about the respective folding line 28 , 36 and fixed, in particular glued, to respective end parts of the bottom panel 38 , and the wings 42 are folded about the respective perimeter lines 40 and fixed, in particular glued, to respective portions of the median panels 22 adj acent to the external sub-flaps 24 . As already indicated, the glue neces sary for the fixing had initially been inj ected on the unfolded parts of the blank to be glued together . Figure 13 illustrates the final configuration of the formed tray 50 due to the downwards movement of the upper member 68 .

Finally, the punch 76 is moved downwards and the upper member 68 is moved upwards ( fig . 14 ) in order to allow acces s to the tray 50 , which can be taken away from the lower plate member 62 and sub jected to further proces sing .

The thus obtained tray 50 has a shape substantially identical to the one illustrated by figure 6, except for the absence of wings 42 departing from the beveled corners 12 of the bottom panel 38 . It can likewise be used for the production of a bowl closed by the plastic sealing film 58 , as illustrated by figure 7 .

An additional advantage brought about by this latter erection method is that all the external surfaces of the final tray 50 were part s of the same face of the initial blank . Accordingly, all the desired graphics signs - namely images , text s and the like - could be printed on this single face of the initial blank, bringing about a meaningful simplification and a sensible cost reduction of the printing process .

Of course , the principles of the invention remaining the same , the details of construction and embodiment s may be widely varied with respect to those described purely by way of example , without thereby departing from the claimed scope . E . g . , the blank may be of any foldable cellulosic material and, depending on the number of sides forming the perimeter of the main panel , the side wall of the tray has the desired number of sides and e . g . is triangular quadrangular, hexagonal, octagonal or dodecagonal .