Machine and method for packaging articles in wrappers

Abstract

A packing machine (M) and method for wrapping a sheet (P), in particular shock-absorbing paper, around an article (A) to form a bag (B), comprising means (4, 5) for folding the sheet around the article, means (6) for adhering the sheet to itself to form a sheet tube (TB) around the article (A), and compression and cutting means (7) for sealing and separating portions of the tube by sealing and separating the upstream and downstream ends of the article, acting on the sheet in a cutting zone located upstream of the sheet folding and adhering means in cooperation with a second adhesive application means (10).

Description

[Technical Field]

[0001] The present invention relates to a machine for packaging items by wrapping, in particular a machine suitable for wrapping sheets of paper material, in particular multi-sheets, and in particular formed from at least one layer of wrapping paper and one layer of embossed paper, said layers being glued to the previous layer to form a sheet capable of absorbing shocks, which are wrapped around items to form closed bags containing individual items. [Background technology]

[0002] Machines that wrap a film around an item to form a closed bag made of a heat-sealable plastic material are commonly known. Because the film used for packaging is usually cellophane, these are commonly referred to as "cellophane wrapping machines." While cellophane wrapping machines are commonly known for packaging individual items, they must be stopped and reassembled when it is desired to perform a type change, especially due to different sizes of the packaged items. Italian Patent Application No. 102018000011148 (not yet published at the time of filing this application) describes a bagging machine designed to overcome this problem by enabling the bagging of different-sized items continuously fed along the same line. The material can be any heat-sealable film, including shock-absorbing film, such as the packaging material commonly known as "bubble wrap."

[0003] However, for various reasons, particularly environmental and economic reasons, it is desirable to use different types of materials rather than the plastic materials used by the aforementioned machines. Indeed, there is an increasing trend (especially after the introduction of certain legal provisions) to prefer paper materials such as cardboard and paper for packaging and bagging. These can also be shock-absorbing materials, have a lower environmental impact, are lighter, can be colored and can be directly printed on. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Italian Patent Application No. 102018000011148 Summary of the Invention [Problem to be solved by the invention]

[0005] It is therefore desirable to use paper materials to bag articles, including different types of articles, on the same machine and in the same operating cycle, without having to stop the machine to accommodate different articles, but rather feeding these articles into the machine despite their different types and sizes. [Means for solving the problem]

[0006] These drawbacks are now overcome by a packaging machine as claimed in claim 1 and a method as claimed in claim 15 attached hereto.

[0007] Further preferred features of the packaging machine according to the invention are set out in the dependent claims.

[0008] One preferred embodiment of the invention will now be described by way of example with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic perspective view of a machine according to the invention; [Figure 2] 2 is a schematic diagram of the steps involved in wrapping a paper sheet around an item to form a bag containing the individual item, as performed by the machine of FIG. 1; FIG. [Figure 3] FIG. 2 is a schematic enlarged view of the detail indicated in box K in FIG. 1. [Figure 4] FIG. 2 is a schematic perspective view of certain important components of the machine of FIG. 1; [Figure 5] FIG. 1 is a schematic perspective view of a detail of the machine in the area where the initial step of wrapping the sheet around the moving article takes place. [Figure 6] FIG. 10 is a schematic diagram of a first means for applying adhesive along the side flaps. [Figure 7] FIG. 2 is a partial schematic perspective view of certain other components of the machine. [Figure 8] FIG. 2 is a partial schematic perspective view of a further part of the machine; [Figure 9] FIG. 10 is a partial schematic perspective view of a second means for applying adhesive to a sheet. [Figure 10] 1 is a partial schematic perspective view of a compression and cutting means for closing and cutting a sheet wrapped in a tubular shape around an article to form a bag; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] With reference to the accompanying drawings, and in particular to Figure 1, M indicates generally a packaging machine according to the invention suitable for wrapping a sheet P around articles A to form bags B containing individual articles.

[0011] The machine M comprises a conveying means 1 suitable for receiving articles A (to be packaged) and conveying them in the conveying direction indicated by the arrow D, a vacuum conveyor belt 2 arranged successively relative to the conveying means 1, a sheet P feeding station 3, for example a reel 30 on which said sheet P is wound in the form of a web, and a feeder for feeding the sheet P transversely to the conveying direction D of the articles A between the conveying means 1 and the conveyor belt 2, and for conveying the sheet P with a central portion PC (as shown in FIG. 2) resting on the conveyor belt 2 and with lateral portions PL1 and PL2 arranged on two opposite sides of the central portion PC so as to project laterally from the conveyor belt 2. a sheet P feeding station 3 that includes a feeding / returning means 31, so that the article A conveyed by the conveying means 1 is positioned above the central portion of the sheet P placed on the conveyor belt 2, and that can hold the sheet P with the article A positioned on the central portion PC by suction by the vacuum conveyor belt 2 and feed it in the traveling direction indicated by arrow E in FIG. 2, which may preferably be the same direction as indicated by arrow D in FIG. 1; and a folding means 4 (better shown in FIG. 3) that is arranged and configured relative to the conveyor belt 2 so as to be able to fold the sheet P in contact with the side portions PL1, PL2 of the sheet P that protrude laterally from the conveyor belt 2.

[0012] According to a preferred embodiment of the present invention, and with particular reference to Figures 3 and 5, the machine M is associated with the conveyor belt 2 and comprises a structure 5 shaped to define a tunnel T through which articles A conveyed by the conveyor belt 2 pass above a central portion PC of the sheet P, and the folding means 4 is shaped and configured to contact the side portions PL1, PL2 of the sheet P protruding laterally from the conveyor belt 2 during sheet feeding, and folds the side portions PL1, PL2 of the sheet P around the structure 5 shaped like the tunnel T so that the two side flaps L1, L2 of the sheet P overlap and form a sheet tube TB that is wrapped around the structure 5 shaped like the tunnel T.

[0013] In particular, a structure 5 shaped like a tunnel T is created such that the tunnel T defines a passage for articles A, the height of the structure relative to the conveyor belt 2 being such that articles A of different sizes and heights, such as individual magazines, magazines stacked together, boxes containing products, etc., can be transported within said tunnel.

[0014] Furthermore, the folding means 4 is configured to contact the lateral portions PL1, PL2 of the sheet protruding from the sides of the conveyor belt 2 and to contact the structure 5 shaped like a tunnel T, folding the lateral portions around the walls of the tunnel T to form a sheet tube TB that accommodates articles of different sizes and heights. In this way, with a single structure and a single machine M configuration, it is possible to wrap the sheet around articles of different sizes and heights that are moving along the conveyor belt.

[0015] The machine M further comprises a first adhesive application means 6 (FIG. 6) positioned above the tunnel-shaped structure 5 and configured to apply adhesive to one of the two edges L2 of the sheet P (consisting of side portions PL1, PL2) before it is superimposed above the tunnel structure; and a compressing and cutting means 7 (FIG. 10) positioned downstream of the tunnel-shaped structure 5 at the gap in the conveyor belt 2 and actuated to clamp the seat tube TB first in front of and then behind (in front of the subsequent article) the position of the article A inside the seat tube TB, thereby gluing and cutting the sheet P and thereby obtaining a bag B containing the article therein. According to a preferred embodiment of the invention, these means for compressing and cutting the sheet can accompany the article A during the compressing and cutting step (allowing for continuous feeding of the sheet and the article), and can be conveyed in the sheet advance direction E and also in the opposite direction so as to return to their initial position while not engaged with the sheet and to resume the cycle with the next article. For example, the compressing and cutting means 7, which is generally known per se, can be mounted on a movable lower carriage 70. The means may be a clamp of suitable shape, as shown in FIG. 10, which can be lowered onto the conveyor belt 2 at the end of the bag being formed and may be equipped with a central blade. According to a preferred embodiment, evacuation means 71 are provided in conjunction with the compression and cutting means 7 to remove air from the bag being formed. Their action reduces the air content in the bag before it is completely sealed and separated from the tube TB. According to one embodiment, the means consists of a suitable sized press 71 located downstream of the compression and cutting means 7. Prior to the action of the cutting means to seal the second end of the bag, the press is lowered and compresses the bag being formed (the first end of which is already sealed, as in FIG. 9, which is the state immediately before the action of the air evacuation means) against the article with a suitable pressure, so as to return the air towards the seat tube TB, thereby reducing the air content of the bag being formed. Immediately thereafter, the compression and cutting means 7 is activated, sealing and separating the bag with an air content such that there is no risk of the bag bursting or increasing in volume.The pressure applied by the press can be adjusted by predetermining (using sensors or other means) the stroke or pressure applied to the bag in a generally known manner to allow air to escape without damaging the product or packaging sheet. Advantageously, the evacuation means can be mounted on the same lower carriage 71 as the compression and cutting means 7. Other systems may also be provided. The evacuation of air achieved in this way before sealing is particularly advantageous with regard to generally known systems, such as those involving perforation of the bag, as is commonly done with plastic bags. Indeed, perforation of paper material, such as that used by the machine according to the present invention, can be employed if deemed appropriate, but tends to weaken the bag and make it more susceptible to tearing. However, this allows the use of different materials, such as paper.

[0016] To seal the ends of the bags by compression, some adhesive must be applied to the sheet P inside the already formed tube TB. In particular, to seal the ends of the two bags that will be separated when cut, adhesive must be placed between one item and the next. For this purpose, a second adhesive application means is envisaged, suitable for applying adhesive to the surface of the sheet P that faces the items and forms the inner surface of the tube TB. Preferably, said means applies adhesive before the tube is formed, more preferably before the sheet is fed onto the conveyor belt 2. The adhesive is applied in relation to the position and size of the items, which are appropriately measured, so that the items are appropriately deposited on the sheet by the conveyor between one adhesive application point and the next.

[0017] Referring to Figure 9, the second adhesive application means 10 comprises a spraying device 11 suitable for spraying adhesive onto the surface of the sheet that will become the interior of the tube being formed, as described above. The second means can be advantageously positioned at the end of the feeding and returning means 31. They are preferably designed to spray adhesive in one or preferably two strips transverse to the sheet advance direction, preferably onto the central portion PC of the sheet. For example, the spraying device 11 may be supplied with adhesive from a tube 12 and feature a series of spray nozzles appropriately oriented towards the sheet P so as to spray adhesive all along the entire area of ​​the relevant sheet P at once, allowing the sheet P to continue moving during the adhesive application step.

[0018] Thus, the machine can wrap the sheet around different items of different sizes and heights to obtain bags containing individual items therein without having to stop the machine and remove and refit components.

[0019] 4 and 5, according to a preferred embodiment, the structure 5 shaped like a tunnel T comprises side walls 51, 52 arranged along the sides of the conveyor belt 2 and at least one top wall 53, 54 between the side walls 51, 52, while the folding means 4 is configured to fold the lateral portions PL1, PL2 of the sheet P around the side walls 51, 52 and the top wall 53, 54 of the structure 5 shaped like a tunnel T, so that the two side edges L1, L2 of the sheet P overlap and form a seat tube TB wrapped around the side walls and the top wall of the structure 5 shaped like a tunnel T. Referring to FIGS. 7 and 8, advantageously, the side walls 51, 52 of the structure 5 shaped like a tunnel T may be made to include fixed lower parts 510, 511 and movable upper parts 520, 521 mounted with the possibility of moving over the lower parts 510, 511 and supporting the top walls 53, 54.

[0020] In this way, the position of the upper parts 520, 521 of the side walls 51, 52 relative to the lower parts 510, 511 can be adjusted and changed to change the distance between the upper walls 53, 54 and the conveyor belt 2, and therefore the height of the tunnel T according to the different actual heights of the articles around which the sheet has to be wrapped.

[0021] 7 and 8, another preferred aspect of the machine M according to the invention resides in the fact that it comprises means 9 for creating an air cushion between the seat tube TB and the structure 5 shaped like a tunnel T. This advantageous means prevents sliding, and therefore friction, between the seat P (and in particular the tube TB formed therefrom) and the walls of the structure 5 shaped like a tunnel T. According to the particular embodiment shown in the figures, the means 9 for creating an air cushion may comprise a duct 91 connected to a source of compressed air and provided with a series of holes 92 for the passage of air. The duct 91 is arranged to direct the jet of air emerging from the holes 92 towards the part of the seat P folded against the structure 5 shaped like a tunnel T. For example, these ducts 91 may be arranged along at least part of the two side walls 51, 52 of the structure 5 shaped like a tunnel T.

[0022] Furthermore, the means 9 for forming an air cushion may comprise a suction belt 93 wound in a closed loop and arranged above the structure 5 shaped like a tunnel T to hold by suction the portion of the sheet P folded onto the structure 5 shaped like a tunnel T. Said belt is used to guide the sheet P in synchronization with the advancement of the conveyor belt 2. According to a further advantageous aspect, the machine M may comprise optical detection means 96 arranged along the structure T for detecting the passage of the articles A through the tunnel T and for detecting the distance between the articles A, and may be configured so that the heat sealing and cutting means 7 remains inoperable if the optical detection means 96 detects that the distance between two successive articles is less than a minimum preset distance. This prevents damage to articles that are too close to each other and would leave insufficient space for the operation of the compression and cutting means 7.

[0023] Referring in particular to Figure 6, according to a preferred embodiment, the first adhesive application means 6 comprises at least one adhesive dispenser 61, fixed abutment elements 62, 63 arranged downstream of the dispenser 61 in the direction of travel E of the sheets P to contact the overlapping edges L1, L2 of the sheets P at the top and facilitate their bonding, and at least one movable abutment element 64 that can be activated when the conveyor belt 2 stops, so that the at least one movable abutment element 64 is positioned over the two overlapping edges L1, L2 of the sheets P and keeps them overlapped, thus keeping the tube TB sealed.

[0024] The machine M therefore comprises suction elements arranged below the conveyor belt 2, so that the conveyor belt 2 holds by suction the central portion PC of the sheet P positioned thereon while the sheet P moves in the direction of travel E.

[0025] As can be seen in FIG. 1, an article loading station 8 can be envisaged, positioned at the beginning of the conveying means 1 and equipped with an identification means 81 configured to detect and identify the identification code given to the article A.

[0026] Finally, according to a further preferred embodiment of the invention, the machine M may comprise detection means 82 arranged along the conveying means 1 and configured to measure the height of the articles A, and the conveying means 1 may be configured to stop when the detection means 82 detects the passage of an article with a height greater than that of the tunnel T. Printing means may be envisaged, if desired, for the sides of the sheets, in particular those that will become the outer parts of tubes and bags. These printing means may be arranged in the feeding and returning means 31. If desired, further processing components may be located downstream of the compressing and shearing means, such as a labeller, capable of printing a label according to the data read from the identification code.

[0027] The tunnel-like structure in the machine M according to the present invention also allows for the use of shock-absorbing packaging sheets. According to a preferred embodiment, the sheet is formed from at least two layers of paper: one smooth and one embossed (featuring concave and convex elements) and bonded to the first layer (forming a shock-absorbing structure). Preferably, when there are only two layers, as described above, the embossed layer faces the inside of the tube, contacting the packaged item. Other layers may also be featured, for example, an embossed layer may be sandwiched between two smooth layers. The embossments may be characterized by recesses with a circular base spaced apart by a distance ranging from 0.3 to 10 mm, e.g., 0.5 mm. Shock-absorbing sheets of this type are known, and different types are commonly manufactured, featuring, for example, different numbers of layers and different sizes of embossments, and are commonly used to encase packaged objects to protect their surfaces as vibration-damping pads. Those skilled in the art can select the type that best suits their needs, such as flexibility, lightweight design, affordability, and protection requirements.

Claims

1. A packaging machine (M) designed to wrap a sheet of paper (P) around an article (A) to form a bag (B) containing the individual article, a conveying means (1) configured to receive an article (A) to be packaged by the sheet and convey it in a conveying direction (D); a vacuum conveyor belt (2) arranged in series with the conveying means (1); a sheet (P) feeding station (3) for feeding the sheet (P) transversely to the conveying direction (D) of the articles (A) between a reel (30) on which the sheet (P) is wound or a similar sheet securing means, the conveying means (1) and the vacuum conveyor belt (2), with a central portion (PC) of the sheet (P) placed on the vacuum conveyor belt (2) and side portions (PL1, PL2) protruding laterally from the vacuum conveyor belt (2) and positioned at the sides of the central portion (PC); a sheet (P) feeding station (3) including a feeding and returning means (31) for arranging the sheet (P) in a state where the article (A) conveyed by the conveying means (1) is arranged above the central portion (PC) of the sheet (P) placed on the vacuum conveyor belt (2), and the sheet (P) with the article (A) arranged on the central portion (PC) can be held by suction by the vacuum conveyor belt (2) and can be fed in the traveling direction (E); folding means (4) arranged and configured relative to the vacuum conveyor belt (2) so as to be able to fold against the side portions (PL1, PL2) of the sheet (P) that protrude laterally from the vacuum conveyor belt (2); a structure (5) associated with the vacuum conveyor belt (2) and shaped to define a tunnel (T) through which the articles (A) conveyed by the vacuum conveyor belt (2) pass above the central portion (PC) of the sheet (P), wherein the folding means (4) is shaped and configured to contact the side portions (PL1, PL2) of the sheet (P) protruding laterally from the vacuum conveyor belt (2) during feeding of the sheet, and folds the side portions (PL1, PL2) of the sheet (P) around the structure (5) shaped like the tunnel (T) so that two side flaps (L1, L2) of the sheet (P) overlap and form a sheet tube (TB) that is wrapped around the structure (5) shaped like the tunnel (T); a first adhesive application means (6) positioned above the tunnel-shaped structure (5) and configured to apply adhesive to one of the two side flaps (L1, L2) of the sheets (P) before overlapping; a compressing and cutting means (7) positioned downstream of the tunnel-shaped structure (5) at the gap in the vacuum conveyor belt (2), which is actuated to clamp the seat tube (TB) first in front and then behind the position of the article (A) inside the seat tube (TB), thereby sealing and cutting the sheet (P) to obtain a bag (8) containing the article therein; a second adhesive application means (10) designed to apply adhesive to the side of the seat that will become the inner surface of the seat tube (TB); Equipped with the first adhesive application means (6) comprises at least one adhesive dispenser (61), fixed abutment elements (62, 63) arranged downstream of the adhesive dispenser (61) with respect to the direction of travel (E) of the sheet (P) in order to contact the two overlapping side flaps (L1, L2) of the sheet (P) and facilitate bonding of the two side flaps, and at least one movable abutment element (64) that can be actuated when the vacuum conveyor belt (2) stops, the at least one movable abutment element (64) being positioned above the two overlapping side flaps (L1, L2) of the sheet (P) to keep the two side flaps overlapped and to keep the seat tube (TB) sealed; Packaging machine (M).

2. 2. The machine (M) according to claim 1, wherein the tunnel-shaped structure (5) comprises side walls (51, 52) arranged along the sides of the vacuum conveyor belt (2) and at least one top wall (53, 54) between the side walls (51, 52), and the folding means (4) is configured to fold the lateral portions (PL1, PL2) of the sheet (P) around the side walls (51, 52) and the top wall (53, 54) of the tunnel-shaped structure (5) so that two lateral edges (L1, L2) of the sheet (P) overlap and form the seat tube (TB) wrapped around the tunnel-shaped structure (5).

3. 3. The machine (M) according to claim 2, wherein the side walls (51, 52) of the structure (5) shaped like the tunnel (T) comprise a fixed lower part (510, 511) and a movable upper part (520, 521), the movable upper part (520, 521) being attached to the fixed lower part (510, 511) with the possibility of movement and carrying at least one upper wall (53, 54), the position of the movable upper part (520, 521) relative to the fixed lower part (510, 511) being adjustable and changeable so as to change the distance of the upper wall (53, 54) from the vacuum conveyor belt (2) and thus the height of the tunnel (T).

4. A machine (M) according to any one of claims 1 to 3, comprising means (9) for creating an air cushion between said seat tube (TB) and said tunnel-shaped structure (5).

5. 5. A machine (M) according to claim 4, wherein the means (9) for creating the air cushion comprise a duct (91) connected to a source of compressed air and provided with a series of holes (92) for the passage of air, the duct (91) being arranged to direct the jets of air emerging from the holes (92) towards the part of the sheet (P) folded against the structure (5) shaped like the tunnel (T).

6. 6. Machine (M) according to claim 4 or 5, wherein the means (9) for creating the air cushions comprises a suction belt (93) wound in a closed loop and arranged above the tunnel-shaped structure (5) to hold by suction the portion of the sheet (P) folded onto the tunnel-shaped structure (5), the suction belt (93) being used to guide the sheet (P) in synchronism with the advancement of the vacuum conveyor belt (2).

7. 7. The machine (M) according to any one of claims 1 to 6, comprising optical detection means (96) arranged along the structure (5) shaped like the tunnel (T) and configured to detect the passage of the articles (A) in the tunnel (T) and to detect the distance between the articles (A), wherein the heat sealing and cutting means (7) are configured to remain inoperable if the optical detection means (96) detects that the distance between two consecutive articles is less than a minimum preset distance.

8. 8. The machine (M) according to any one of claims 1 to 7, comprising a suction element arranged below the vacuum conveyor belt (2), which holds by suction the central portion (PC) of the sheet (P) positioned on the vacuum conveyor belt (2) while the sheet (P) moves in the forward direction (E).

9. A machine (M) according to any one of claims 1 to 8, comprising an article loading station (8) positioned at the beginning of the conveying means (1) and equipped with an identification means (81) configured to detect and read an identification code given to the article (A).

10. A machine (M) according to any one of claims 1 to 9, comprising detection means (82) arranged along the conveying means (1) and configured to measure the height of the article (A), the conveying means (1) being configured to stop when the detection means (82) detects the passage of an article that is higher than the tunnel (T).

11. A machine according to any one of the preceding claims, wherein the second adhesive application means is capable of applying adhesive in strips transverse to the direction of travel of the sheet.

12. A machine according to any one of the preceding claims, wherein the second adhesive application means is positioned in the feeding and returning means (31) upstream of the feeding point of the sheet onto the vacuum conveyor belt (2).

13. 6. A machine according to claim 5, comprising means (72) for evacuating the air from the bag being formed, said means (72) being designed to act in cooperation with said compressing and cutting means (7) and to compress the seat tube (TB) against the article before sealing and separating the bag from the seat tube.

14. 14. A packaging method, in which an article to be packaged is wrapped in a sheet comprising at least two layers of paper by a machine according to any one of claims 1 to 13, one layer of said paper being a smooth layer and one layer being embossed and glued onto said smooth layer.

15. The method of claim 14, wherein the smooth layer is the outer surface of the seat tube and the outer surface of the formed bladder.

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