METHOD OF MANUFACTURING A PACKAGING FOR FLAT PLATES AND BLANK FOR SAID PACKAGING.

Abstract

A blank and a container are described, as well as a method for manufacturing a container for flat plates, comprising the steps of: - producing a foldable flat piece (B) made of a packaging material, - folding said flat piece (B) to form a box-shaped container with open, closable flaps, - inserting said flat plates into said box-shaped container and closing said closable flaps. In the production step of the flat blank, the following steps are further provided: - supplying a strip of said wrapping material to a punching and sorting unit (1) to obtain strips (C1-Cn) parallel to a direction of travel, - punching and separating from said strips (C1-Cn) a plurality of elongated modular pieces (P1-Pn), - flat-folding said elongated modular pieces (P1-Pn) into an L-shape, bringing them together in pairs at their respective ends.- securing said modular pieces (P1-Pn) folded in an L shape in correspondence with the respective ends, forming said raw piece (B) in the form of a quadrangular frame.

Description

METHOD FOR MANUFACTURING A CONTAINER FOR FLAT PLATES AND A BLANK FOR SAID CONTAINER FIELD OF INVENTION The present invention relates to a method of manufacturing a container for flat plates, a blank for said container and an apparatus for manufacturing the same, in particular a method of manufacturing containers or boxes for wrapping flat plates, such as tiles, stone slabs, glass panels, laminated sheets, etc. BACKGROUND OF THE INVENTION In industrial lines dedicated to packaging with paper boxes, product units are packaged inside cardboard boxes traditionally obtained by bending die-cut cardboard. It is currently in the paper industry that the die-cutting technique has spread dramatically, allowing for identical and precise cuts of special and complex shapes from paper, cardboard, and similar materials. Blank cardboard is typically obtained as a flat tray with a suitable shape, through die-cutting or other operations, according to the specific box size. On the perforated flat tray, a creasing operation is performed along specific lines, allowing for uniform and precise folding of the flat material, due to the pressing of the paper or cardboard along the predetermined fold lines. In recent years, the packaging of flat products for the construction industry, particularly tiles, has generally adopted an alternative technique to traditional die-cutting boxes. It has been shown that, unlike bulk packaging, flat sheet material in piles, such as sheets, laminates, and tiles, does not technically require a full-size containment box. Packaging that consolidates the various pile sheets, protecting only their sides and edges, is sufficient. This allows for the saving of a significant portion of the box's cardboard, which would otherwise cover the surface of the sheet or tile, serving no practical purpose. This technology uses cardboard strips, which are cut and shaped appropriately within a very complex packaging line, within which a cardboard bandage or containment frame is built around the stack of tiles. Examples of this technology are illustrated, for example, in EP2952437, WO2016156928 and WO2017149422. The frame system represents a valid alternative to replace traditional tray-shaped cardboard, obtaining significant advantages not only in terms of raw material savings, 7ñ7ierV but also easy size adaptability, resulting in a drastic reduction of obsolescence and cardboard stock in the warehouse. However, perimeter tile wrapping machines are inherently complex, as they must create a complete wrap from very simple cardboard strips and simultaneously move a series of heavy stacks of tiles along the line, around which the wrapping is constructed, making them quite expensive. Furthermore, they completely replace any pre-existing traditional boxing lines (i.e., those using classic die-cut trays) in factories, which entails the unpleasant dismantling of previous investments. Therefore, a packaging method and device are needed that can balance the unique advantages of perimeter framing with relative material savings and size adaptability, while also ensuring that investments already made for conventional boxing equipment are not wasted. BRIEF DESCRIPTION OF THE INVENTION The objective of the present invention is, therefore, to offer a solution that solves the problems mentioned above and provides a method and apparatus for obtaining a simple and effective system for producing a container for stacked flat plates, which allows for significant material savings compared to classic packaging boxes, but which exploits at least partly the traditional packaging machines that use pre-perforated trays. This objective is achieved according to the invention by means of a method of producing containers for stacks of flat plates, such as tiles, having the characteristics defined in claim 1. Other preferred features of the invention are defined in the dependent claims. BRIEF DESCRIPTION OF THE FIGURES Other features and advantages of the invention will in any case become more evident from the following detailed description of a preferred embodiment, given as a non-limiting example and illustrated in the accompanying drawings, where: Figure 1 is a schematic top plan view of a production line for packaging blank parts according to the present invention; Figure 2 is a detail view of Figure 1, showing a continuous longitudinal cutting and unwinding station; Figure 3 is a view of another detail from Figure 1, showing a punching and sorting station; Figure 4A is an illustrated top plan view of an exemplary die-cut cardboard piece obtained using the method of the invention, while Figure 4B is a schematic top plan view of another exemplary die; Figure 5 is a view of another detail from Figure 1, showing a folding station and 7Λ7ΙΒΓΥ preparation of the individual pieces; Figure 6 is a view of another detail from Figure 1, showing a blank part assembly and gluing station; Figure 7 is a view of another detail from Figure 1, showing an application station where angle guards are applied; Figure 8 is a view of another detail from Figure 1, showing a stacking and storage station; and Figure 9 is a pictorial view of three representative photographs of three folding steps with angled locking flaps. DETAILED DESCRIPTION OF THE PREFERRED MODALITY In a system for packaging flat sheets, such as tiles, a traditional boxing line is advantageously used, in a manner known per se, where a flat blank is folded and glued to form a box, into which a stack of flat sheets is inserted before being properly closed. For this purpose, a boxing line comprises at least a folding apparatus, a filling unit, and a system for closing the top flaps. However, according to the invention, one or more traditional boxing lines are not supplied with classic perforated trays, but are preceded by an original blank creation line, which is described in detail below. The blank creation line according to the invention, as clearly highlighted in Figure 1, comprises a plurality of staggered stations, intended to create a flat blank having an original design, usable in a traditional boxing line, from flat material of a standard shape, such as rolls of paper or sheets of a suitable thickness, smooth cardboard, corrugated cardboard or the like. At a first stretching and unwinding station 1, the semi-finished flat wrapping material C, for example thin corrugated cardboard, arranged in supply units 10 on concertina-shaped piles or reels, is stretched and delivered to a line conveyor for processing. If the material is available in the form of separate stacked sheets, a joining station (not shown) may be provided downstream of drawing station 1. This station joins two or more sheets in series by gluing, for example, with vinyl or hot-melt adhesive. This operation is intended to obtain a continuous flow of material, if required. In this case, a pressure section may be provided on the machine to perform local compression of the flat material, reducing the thickness of the overlap areas at the leading and trailing edges of the individual sheets. Just downstream of the drawing and the possible joining of the continuous sheets, the flat cardboard material is cut into a longitudinal cutting unit 11. At this stage, the continuous web of material is divided into a plurality of Ci-Cn strips of the desired width, preferably a uniform number of Cn strips, for example, six strips of uniform width. The width of the Ci-Cn strips can be defined as desired, for example, by changing the distance between the axes of the cutting blades provided at this station. Subsequently, the flat semi-finished material, divided into strips Ci-Cn, is processed in a punching and sorting station 2. In this station, a die-cutting operation, possibly assisted by a transverse blade unit (not shown), separates the continuous strips Ci-Cn into a plurality of bands or modular pieces, Pi-Pn, of the desired length. The length of the modular pieces Pi-Pn can be easily changed by adjusting the rate of the die-cutting operation during the continuous sliding motion of the flat material C along the line and / or the rate of operation of the transverse blades that separate the individual pieces from the continuous material. Preferably, a folding line definition operation is also performed at the same time, for example, by folding or cutting short rectilinear discontinuous incisions, along predefined lines on Pi-Pn pieces, to facilitate the folding of P,-Pn pieces, in particular along longitudinal lines and an oblique line in a centerline area that divides each piece into two parts. The preferred shape of the individual Pi-Pn modular pieces (as shown in Figures 4A and 4B) provides a generally rectangular shape, with a wide rectangular cut Cf around the mid-length of the piece, extending from the longitudinal edge to beyond the longitudinal axis of the modular piece's centerline. The rectangular cut Cf ideally divides the modular piece Cn into two opposing branches Ca1 and Ca2, with a length proportional to the two sides of the flat plates to be packaged. From a Caí of the two opposite branches, two opposite appendages or fins Ce project out, extending substantially over the longitudinal axis of the central line of the modular piece. In the cutting operation that occurs at drilling station 2, the Ci-Cnse strips are formed in the shape of the individual modular pieces (Figures 4A and 4B), preferably operating in such a way that a specific pattern is applied to half of the modular pieces arranged on one side of the longitudinal axis of the line and a mirror pattern is applied to the other half of the modular pieces arranged symmetrically on the other side of the longitudinal axis of the line (as shown in detail in Figure 3). At the end of the punching process, the modular parts are drawn in mirror-image pairs, Pi Pn, P2 Pn 1, PsPn 2..., and arranged in two feed rows along a delivery line (see the right-hand side of Figure 3). Essentially, all the Pi-Pn modular parts are sorted into just two feed rows, keeping them side-by-side in mirror-image pairs, designed to cooperate in a complementary manner. A printing station (not shown) is possibly provided along the feed row, where a printing machine is located that applies writing, logos, and other graphic representations to the individual modular pieces. 7Λ7ΙΒΓΥ After punching and sorting station 2, the individual modular parts are collected, off the feed line, in a supplementary buffer area (part of the left side of Figure 5), where suitable accumulators are located to store these parts until they are used in the downstream processing unit. An operational processing module is then prepared for the reintroduction of mirror and complementary pairs of modular parts at the appropriate rate to the downstream processing unit. At a consolidation station 3, the complementary modular piece pairs Pi-Pn are processed in a folding unit 31. In particular, each modular piece is then folded along an oblique line, at approximately 45°, arranged in a mid-area corresponding to cut Cf, to bring the two opposite branches Caí and Ca2 of each piece Pn, from a longitudinally aligned condition to an orthogonal relative attitude, i.e., at 90° to each other (as highlighted in Figure 5). The fold line, as seen above, can be predetermined with a fold or discontinuous incision. The folding is done in such a way that the cut part Cf remains open to the outside of the angle formed by the two branches Caí and Caí of each piece Pn. Each of the modular pieces takes an L-shaped profile and, as they have been previously arranged in mirror pairs, they end in complementary L-shaped pairs as shown in Figure 5. Therefore, they are arranged to be placed side by side in correspondence with the respective ends to form an ideal quadrangular frame. The two complementary modular pieces Pi and Pn, after being placed side by side, and possibly partially overlapping, corresponding to the two respective ends, are then securely fastened in an assembly and consolidation station 4. The fixing between the two L-shaped modular pieces is generally achieved by gluing the mutual ends, at the points called G in Figure 6, in ways known in the field, preferably by means of hot melt so that the consolidation of the adhesive occurs in a short time after cooling. As can be clearly seen from Figure 6, the two mutually welded modular pieces form a final blank B that is very similar to a traditional tray-shaped die, where, however, only a rectangular frame is defined, with an open window in the middle. The size of the blank can be easily adjusted by changing the width and length of the two branches Ca1 and Ca2 of the modular piece online. The final blank piece B forms a flat, square frame of a semi-finished material, for example corrugated cardboard, preferably provided with longitudinal fold lines (creased or embossed) suitable for subsequent folding. For example, two lines are provided. 7ñ7ierV of folding Li and L2, carried out at the punching and sorting station 2, along which each side of the blank frame can be subsequently folded a first time, at 90° - to define a perimeter edge to contain the container - then a second time at 180° - to define a closure flap of the container. An additional finishing station 5 (Figure 7) is possibly provided where additional packaging protections are applied. In particular, at the corners of the rectangular blank B—near the position where the raw material has a triangular cut resulting from folding the modular pieces around the cutouts Cf—filler elements or patches R and protective material, such as polyurethane or polystyrene boards, can be applied. The patches R are attached to the cardboard material by gluing, stapling, or a similar method. These corner protectors are intended to remain inside the packaging, adjacent to the corners of the flat plates to be packaged, therefore, they perform a protective function with respect to impacts. Finally, target B is sent to stacking and storage station 6. At this point, the blank B pieces are available to be supplied to the conventional boxing line, where they are folded to form a box-like container, filled with a stack of plates and / or tiles, and then closed by exploding the predetermined closure lines Li and L2. In the folding stage of this box-type container, the Ce flaps are possibly also exploited to create a pull between the side flanks, while defining an angular closure and an inner reinforcement area that protects the corners of the packaged material (see photographs 1-3 in Figure 9). The resulting box-shaped packaging actually covers and consolidates its contents (i.e., the stack of plates) mainly along the side edges and corners, as well as short perimeter bands on the top and bottom surfaces of the stack, yet leaving a large portion of the larger surface of the plates exposed, thus saving packaging material. The complete packaging process is briefly described below for clarity, in accordance with the method of the present invention. In the first stage of packaging operations, unless standard products are involved, a stack of flat plates, such as a batch of tiles to be packaged, is measured. Based on these measurements, the production of a plurality of blank pieces B is initiated by the production line illustrated in Figure 1. This involves adjusting the cutting length and width of the Ci-Cn strips, as well as the position of the Cf cuts, thus determining the absolute and relative lengths of the two opposing branches Caí and Ca2. Production of the resulting blanks B begins and ends when stacking station 6 has received a sufficient quantity to package the provided batch. After that, flat pieces B are introduced into the feeder of a conventional boxing line, where they are folded to form a box-shaped container in which the flat plates are placed, before the container is closed. As can be inferred from the description above, the solution proposed by the invention perfectly achieves the objectives set out in the premises. The packaging production method uses a continuous sheet semi-finished material, obtaining tray-shaped blanks sized and adjusted according to the requirements of the batch to be packaged, making the storage need for each specific box size extremely precise. The blank piece obtained is specifically designed for packaging stacked solid products, where the packaging need is limited to consolidating the various stacked pieces and protecting their thin edges, making the coating of the main surfaces of the stack super-thin, where in fact the packaging is devoid of material for the benefit of saving costs. Furthermore, the production line advantageously supplies a blank that is perfectly compatible with conventional boxing lines that use pre-cut, tray-shaped blanks. This represents a significant safeguard for investments already made by tile manufacturers, as the blank production line can be supported by existing boxing machinery rather than replacing it. Moreover, the fact that the flat slabs are not transferred to the packaging line results in a lighter, cheaper, and faster production line. However, it is understood that the invention should not be considered limited to the particular provisions illustrated above, which represent only illustrative modalities of the same, but that different variants are possible, all within the reach of a person skilled in the art, without departing from the scope of protection of the invention, which is defined exclusively in the following claims. For example, the shape of the individual modular pieces may also differ from the one illustrated, to suit the specific requirements regarding both the type of product to be packaged and the conventional boxing line used. Finally, although reference has always been made to the packaging of stacks of flat plates, it is not ruled out that the method can also be used to package stacks of other large surface products (therefore, which do not require containment walls with regard to bulk products), for example, plates (also of a concave surface) or slabs of various shapes.

Claims

1. A method for manufacturing a container for flat plates, comprising the steps of: - producing a foldable flat piece (B) of a wrapping material; - folding said flat piece (B) to form a box-shaped container with open, closable flaps; - inserting said flat plates into said box-shaped container and closing said closable flaps; wherein said step of producing a flat blank comprises the steps of: - supplying a strip of said wrapping material to a punching and cutting unit (1) to obtain strips (Ci-Cn) parallel to a direction of travel; - punching and separating from said strips (Ci-Cn) a plurality of elongated modular pieces (Pi-Pn); - flat-folding said elongated modular pieces (Pi-Pn) into an L-shape, bringing them together in pairs at their respective ends; - securing said L-folded modular pieces (Pi-Pn) at their respective ends.forming said blank piece (B) in the shape of a quadrangular frame.

2. Method according to claim 1, wherein said clamping stage of the modular pieces (Pi -Pn) folded into an L shape in correspondence with the respective ends provides a gluing stage.

3. Method according to claim 1 or 2, wherein said folding operation provides that each modular piece (Pi-Pn) is folded along an oblique line, at approximately 45°, arranged in a mid-area, so as to bring two opposite branches (Caí and Ca2) of each modular piece from a longitudinally aligned condition to a relative orthogonal orientation.

4. Method according to claim 3, wherein said step of perforating a plurality of elongated modular pieces (Pi-Pn) provides to shape said modular pieces (Pi-Pn) substantially into a rectangular shape with a wide rectangular cut (Cf) in a middle area, extending through a lateral edge until it passes over a longitudinal centerline axis of said pieces, said rectangular cut (Cf) dividing said two opposite branches (Caí and Caz) having respective lengths proportional to the sides of a flat plate to be packaged.

5. Method according to claim 4, wherein from one (Caí) of said opposite branches, two opposite fins (Ce) are projected, extending substantially over the longitudinal axis of the centerline of said modular pieces.

6. Method according to claims 4 or 5, wherein said folding step is performed so that the cutting part (Cf) remains open to the outside of the angle formed by the two branches (Caí and Caz) of each piece Pn.

7. Method according to any of the preceding claims, wherein a step of defining longitudinal folding lines (Li and Lz) in said elongated modular pieces (Pi-Pn) is further provided before said L-shaped folding step.

8. Method according to any of the preceding claims, wherein further a step of applying additional protections (R) is provided in the vicinity of the vertices of said rectangular blank piece (B), said protections (R) being arranged on a side intended to remain inside the container.

9. Flat blank piece for the production of a box-shaped container, consisting of a pair of elongated modular pieces (Pi-Pn), folded into an L shape and fastened at their respective ends to form a quadrangular frame.

10. The blank according to claim 9, wherein said elongated modular pieces (Pi-Pn) are substantially rectangular in shape with a wide rectangular cut (Cf) in a middle area, extending through a side edge to pass over a longitudinal centerline axis of said pieces, said rectangular cut (Cf) dividing the elongated modular pieces (Pi-Pn) into two opposite branches (Caí and Ca2) having a length proportional to the sides of the flat plates to be packaged.

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