DESCRIPTION

TECHNICAL FIELD

The present invention relates to improvements to machines and methods for producing packs of rolls, in particular but not exclusively rolls of tissue paper, such as toilet rolls, kitchen towel and the like. The invention also relates to improvements to the packs of the aforesaid products.

STATE OF THE ART

Rolls of tissue paper, such as toilet paper, kitchen towel and the like, are usually packaged in wrapping sheets made of plastic material, i.e., in polymer film. A plurality of rolls are arranged in an ordered manner to form a geometrically ordered group, with one or more rows of rolls, each of which comprises one or more superimposed rolls. These ordered groups of rolls are wrapped in a wrapping sheet that surrounds the group of rolls laterally and that has flaps folded against the substantially flat opposite faces formed by the flat faces of the rolls, and mutually welded.

Machines for wrapping groups of rolls in wrapping sheets are described, for example, in US 6308497, US 7707805, US 7703264, US 2014/0260087, and in US 8430232, EP1067048, EP1312549, EP1992562, US8727106, US7654386, EP1228966.

The flaps of the wrapping sheet, mutually overlapped and folded over the substantially flat faces of the group of rolls, are welded by means of a heat welding device. Examples of welding devices are described in US 2004/0151481 and in EP 2213577, EP1539586.

The substantially flat and opposite faces of the packs thus obtained have irregular surfaces due to the thermal deformations of the plastic film caused by the heat welding. The welded area remains exposed and in some cases, can be damaged due to the handling to which the packs are subjected.

In some cases, welding defects can occur. If welding is incomplete, the pack obtained is not sealed, but can have imperfections and apertures. This can occur, for example, in the event of insufficient welding temperatures. In other cases, excessive welding temperatures can cause perforation of the plastic film, with which the wrapping sheet is produced. The wrapping sheet is usually print- ed, for example screen printed, with the manufacturer's brands, decorations or other technical or advertising information. Printing on the plastic film must be limited to the area of the film that is wrapped around the lateral surface of the pack, while the flaps that are folded and overlapped on the substantially flat and opposite faces of the pack must generally be free of printing, as these areas are welded.

US2012/0145733 discloses a pack for rolls of tissue paper wrapped in a welded plastic film. A handle formed by a self-adhesive sheet material is applied to the welded pack. The handle is applied to the smooth lateral surface or along a transverse weld of the pack.

US4119268 discloses a bag made of plastic material, which has two ends, respectively a bottom and an opposite top end. A self-adhesive handle is applied to the top end.

FR809693 discloses a paper pack with one end closed by means of an adhesive handle.

GB883408 discloses a pack for bread with a bottom and an opposite opening, closed with a perforated sheet.

Therefore, packs of this type have some drawbacks linked to the configuration of the welding areas.

SUMMARY OF THE INVENTION

According to a first aspect, there is provided a pack of rolls of tissue paper, comprising a geometrically ordered group of rolls and a wrapping sheet that laterally wraps the geometrically ordered group of rolls and forms folded flaps on two substantially flat and opposite faces of the pack. Moreover, it is further provided that an adhesive sheet is applied to said folded flaps of at least one of the two substantially flat and opposite faces of the pack.

The substantially flat surface is, in practice, formed by the flat and exposed face or faces of the roll or rolls forming the geometrically ordered group of rolls.

The geometrically ordered group of rolls can also comprise a single roll. Preferably, the geometrically ordered group of rolls comprises a plurality of rolls, arranged in two or more rows and in one or more layers.

Preferably, the folded flaps are mutually overlapped and can be mutually welded. In other embodiments, the adhesive sheets can be used to fix the folded flaps.

Preferably, the adhesive sheets are applied to both the substantially flat and opposite faces.

The adhesive sheet or each adhesive sheet advantageously covers a wide surface of the flat face, for example at least 30%, preferably at least 50%, or at least 70%, more preferably at least 80% of the surface of the respective substantially flat face.

The adhesive sheet can be used to fix the flaps of the wrapping sheet and/or to cover the weld area of the folded and overlapped flaps, for example for aesthetic reasons, to cover any welding defects, such as holes or areas that are not completely welded. Moreover, the adhesive sheets can be printed, so as to complete the print of the wrapping sheet, normally provided on the lateral surface of the pack.

According to some embodiments, the pack comprises a holding handle.

The holding handle can be formed of an elongated element, for example a strip of plastic film, paper, cardboard or other material, fixed adhesively between the adhesive sheet and the wrapping sheet that wraps the rolls. For example, the elongated element can have two ends fixed between the adhesive sheet and the substantially flat face of the pack.

In other embodiments the handle can be formed by the adhesive sheet itself, rather than consisting of a further and separate element, which is fixed adhesively to the pack by means of the adhesive sheet. For example, the handle can be formed by incisions or cuts made in a central non-adhesive area or portion of the adhesive sheet. In other embodiments, the adhesive sheet can be folded to form one or two wings applied adhesively to the substantially flat face, and a projecting portion or two projecting and folded portions, forming a handle. Holding can be facilitated by providing apertures, holes or cut-outs in the sheet.

According to a further aspect, a method for producing a pack of rolls is provided, comprising the steps of:

forming a geometrically ordered group of one or more rolls;

wrapping a wrapping sheet around the geometrically ordered group of rolls and folding and mutually overlapping flaps of said wrapping sheet on two substantially flat and opposite faces defined by the geometrically ordered group of rolls.

The method further comprises the step of applying an adhesive sheet to at least one of the substantially flat and opposite faces.

According to yet another aspect, there is provided a machine for produc- ing packs of rolls comprising:

a wrapping station, configured and arranged to wrap a geometrically ordered group of rolls in a wrapping sheet, forming folded and overlapped flaps of said wrapping sheet on two substantially flat and opposite faces of said geometrically ordered group of rolls;

along a feed path of the geometrically ordered groups of rolls, downstream of the wrapping station with respect to the direction of feed of the geometrically ordered groups of rolls along the feed path, a station for applying adhesive sheets to at least one of said two substantially flat and opposite faces.

Disclosed herein is also a pack of rolls of tissue paper, comprising:

- a geometrically ordered group of one or more rolls;

- a wrapping sheet that laterally wraps the geometrically ordered group of one or more rolls and forms folded flaps on two substantially flat and opposite faces of the pack

characterized in that an adhesive sheet that forms a handle or by means of which a handle is applied to the substantially flat face is applied to at least one of the two substantially flat and opposite faces.

Further advantageous characteristics and embodiments of the method, of the machine and of the pack are described hereunder and in the appended claims, which form an integral part of the present description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood by following the description and accompanying drawing, which shows practical embodiments. More specifically, in the drawing:

Fig.1 illustrates a plan view of a portion of packaging line to which machines according to the invention are added;

Fig.2 illustrates an enlargement of a head for applying the adhesive sheets to the pack; Figs. 3 A to 3H illustrate a sequence showing the formation of a pack according to the method described herein;

Fig.4 illustrates another embodiment of the pack;

Figs. 5A-5F illustrate other embodiments of the pack with a holding han- die.

DETAILED DESCRIPTION OF EMBODIMENTS

The following detailed description of the exemplary embodiments refers to the accompanying drawings. The same reference numbers in different draw- ings identify the same or similar elements. Additionally, the drawings are not necessarily drawn to scale. Also, the following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims.

Reference throughout the specification to "one embodiment" or "an em- bodiment" or "some embodiments" means that the particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrase "in one embodiment" or "in an embodiment" or "in some embodiments" in various places throughout the specification is not necessarily referring to the same embodiment(s). Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

Fig.1 schematically shows a plan view of the end portion of a production line of packs of rolls of web material, such as tissue paper. In the portion of line represented in Fig.l, reference 1 indicates the station in which wrapping of each geometrically ordered group of rolls in a wrapping film is carried out, hereinafter referred to as wrapping station. The wrapping station 1 can comprise a welding unit 1A that welds the overlapped folded flaps of wrapping sheet. The wrapping station 1 and the welding unit 1A can be configured in a known manner, for example as described in the patents cited in the section of the present description dedicated to the state of the art.

Reference 3 indicates a feed path of the packs obtained from the station 1 toward a station 2 that can comprise a bundler of known type, in which a plurality of packs are inserted in bags of larger size for subsequent transport. Reference F indicates the direction of feed of the packs from station 1 to station 2. Characteristically, downstream of the wrapping station 1, between this latter and the bundler, a station 5 for applying adhesive sheets to the opposite substantially flat and opposite faces of the pack, produced by the wrapping station 1, is arranged.

In the embodiment of the Fig.l, the station 5 for applying adhesive sheets comprises four working heads labeled 7 A, 7B, 9 A, 9B, arranged in pairs on opposite sides of the feed path 3. The four heads are substantially the same and one of them is shown in the enlargement of Fig.2. In the embodiment illustrated in Fig.l, four heads are provided, to allow the station 5 for applying the adhesive sheets to operate continuously, even during the replacement of consumables, i.e. of the adhesive sheets that the station applies to the packs in transit through it. More in particular, the heads 7 A, 7B, 9 A, 9B are arranged so that, while the heads 9A, 9B of one pair are operating, the heads 7A, 7B of the other pair can be idle to allow the exhausted reels of consumable, i.e. adhesive sheets, to be re- moved and replaced with new reels. In other embodiments, a single pair of heads 7 A, 7B, or 9 A, 9B can be provided, in which case the line is stopped to carry out the change of the consumable.

In some embodiments two or more pairs of heads can be provided, and at least two pairs of heads can be used simultaneously, making them operate alter- nately, i.e., using, for example, a first pair to apply the adhesive sheets to the packs at even positions and the other pair to apply adhesive sheets to the packs at odd positions in the flow of packs coming from the wrapping machine 1. More in general, a pair of heads applies the adhesive sheets to some packs and the other pair of heads applies the adhesive sheets to the remaining packs. This can be useful, for example, if it is desirable to provide the packs with adhesive sheets of two different types. The concept can be extended to more than two of pairs of heads and consequently to more than two different types of adhesive sheets.

In this case, to carry out the change of the consumable it is possible to provide a redundant number of pairs of heads with respect to the number of pairs operating simultaneously. For example, three pairs of heads can be provided, two operating and one standing by, which is loaded with the consumable and replaces the first one of the two operating pairs that exhausts the consumable. In this way a total redundancy (i.e. four pairs of heads) is not necessary. It would also be possible to use heads capable of performing a change on-the-fly of the consumable.

Fig.2 schematically illustrates an enlargement of one of the heads 7A-9B, which are substantially the same. Reference Bl indicates a reel, on which a backing web is wound; on the backing web adhesive sheets are removably attached, which are to be applied to the packs advancing through the station 5 for applying the adhesive sheets. Reference B2 indicates a reel on which the exhausted backing web is wound, i.e. the backing web from which the adhesive sheets have been detached and applied to the packs advancing through the sta- tion 5 for applying the adhesive sheets.

In practical embodiments, the heads 7A-9B are labeling heads of suitable size.

Each head 7A-9B comprises an applicator blade 11 arranged with a free end thereof close to the substantially flat faces of the packs C that advance along the feed path 3. A backing web N unwound from the reel B l, and to which detachable adhesive sheets E are applied, is guided around the corner or distal edge of the applicator blade 11, so that, by synchronizing the feed movement of the backing web N with the advance of the packs C along the path 3, the adhesive sheets E are detached from the web N and are transferred to the respective sub- stantially flat face of the pack C, close to which the distal edge of the respective blade 11 is positioned. The adhesive present on each adhesive sheet E causes gluing of the adhesive sheet E to the flat face of the pack. By arranging two heads on the two opposite sides of the feed path 3 adhesive sheets or labels E are applied to both the flat and substantially opposite faces of the pack C.

Contrary to what is represented in Fig. 1, in other embodiments a single pair of working heads 7A, 7B can be provided. In this case, replacement of the consumables requires the production line to be temporary stopped. If necessary, an accumulator of the packs or of the single rolls can be provided upstream of the station 5 for applying the adhesive sheets.

While preferably two opposite adhesive sheets are applied to each pack, one on each flat face, it would also be possible to apply these adhesive sheets to only one of these faces.

The adhesive sheets E are provided with a pressure- sensitive adhesive. Any pressure- sensitive adhesive of known type, suitable to adhere to the materi- al of which the wrapping sheet Fl is formed, can be used. In some embodiments, to improve adhesion, a pressure system, for example comprising a rubber coated roller, indicated schematically with 12 in Fig.2, can be provided downstream of the area for transfer of the adhesive sheet E from the backing web N to the pack C. Any other pressure system, such as a sliding shoe, can be provided instead of a roller, although a roller is currently preferable as it does not impede the regular advance of the packs along the feed path 3.

The method for producing the packs of rolls is illustrated in detail in the sequence of Figs.3A-3G. These figures only show: the rolls to be packaged indi- cated with R, the wrapping sheet with which the pack is formed, and the adhesive sheets E applied in the station 5 for applying the adhesive sheets. The mechanical members of the various stations mentioned above are omitted, as they are known or described with reference to Figs. 1 and 2.

Fig.3A shows an initial step, in which a geometrically ordered group G of rolls R is wound with a wrapping sheet Fl, typically a plastic film. In the illustrated embodiment the geometrically ordered group G of rolls R has an array of 2x4 rows of rolls, where each row contains 3 rolls. It must be understood that this configuration is provided by way of example only and that the number and the arrangement of the rolls R in the geometrically ordered group G can differ from those illustrated. The only fact that is relevant is that the geometrically ordered group G of rolls R has two substantially flat and opposite faces, defined by the flat faces of the various rolls R exposed on the two sides of the pack.

Fig. 3B shows the subsequent step in which the wrapping sheet Fl has been wound completely around the lateral surface of the geometrically ordered group G of rolls R, overlapping two edges LI, L2 parallel to the axes of the rolls R. These edges can be welded to one another in a manner known per se.

The wrapping sheet Fl has a width H greater than the height of each row of rolls R, so that two opposite portions of wrapping sheet Fl project from the geometrically ordered group G of rolls R. These portions are folded to form flaps F2 that are folded and turned over against the substantially flat and opposite lateral faces of the geometrically ordered group G of rolls R. The folded flaps are mutually overlapped, see Figs.3C, 3D and 3E. Fig.3F shows the pack C formed by the geometrically ordered group G of rolls R and by the wrapping sheet Fl wound around them. The pack C, not yet completed, is delivered from the wrapping machine 1 in this configuration.

The pack thus produced can be made to pass through the welding unit 1A of the wrapping station 1. The welding unit 1A has welding members that cause heat welding of the folded flaps F2 which are overlapped to the two substantially flat and opposite faces of the pack C.

In some embodiments, the welding unit 1A can be omitted. In embodiments of the method, the welding unit can be deactivated. In the case in which the welding unit 1A is not provided, or said unit is deactivated, it is possible to use wrapping sheets made of non-thermoplastic material, such as paper, the wrapping folds of which are stabilized with the use of the adhesive sheets E. In particular, in this case the pack C can be formed of a single roll R and therefore the geometrically ordered group consists of a single roll of paper.

If the welding unit 1A is not provided or is deactivated, between this latter and the area of application of the adhesive sheets E, i.e., in the area in which the blades 11 of the heads 7A-9B are located, members to contain the folded and overlapped flaps F2 can be provided, to prevent the flaps from re-opening. For example, feed belts can be provided that remain in contact with the substantially flat and opposite faces of the pack C. Alternatively, stationary surfaces, such as stationary plates, preferably made of or coated with a material with low coefficient of friction, such as Teflon® or the like, can be provided. In this case the packs run along the plates and in contact therewith.

In the station 5 for applying the adhesive sheets, two adhesive sheets E are applied to the two substantially flat opposite faces of the pack C, as schematically illustrated in the Figs.3G and 3H.

Fig.3H illustrates the finished pack C, complete with adhesive sheet E applied to the visible substantially flat face. A similar adhesive sheet E is applied to the opposite face (not visible in Fig.3H). The two adhesive sheets E applied to the two substantially flat and opposite faces of the pack C can be the same or different. For example, they can be of different shape or different size. In some cases, one or the other of the two adhesive sheets E can be printed. In this case, the prints on the two adhesive sheets E of the same pack can be different. Preferably, each adhesive sheet E has a sufficiently large surface to cover the majority of the area of the corresponding substantially flat face to which the adhesive sheet E is applied. For example, the sheet E can reach the lateral edges of said substantially flat face. The adhesive sheet E can also have an edge shaped to follow the rounded shape of the substantially flat face to which it was applied, the rounding being present in the corners and being determined by the cylindrical shape of the packed rolls.

Each adhesive sheet E is used to cover the overlapped flaps F2, so as to protect them and to prevent their creased appearance from giving the pack C an aesthetically unappealing impression.

The adhesive sheets E further perform the function of stabilizing the folded and overlapped flaps F2. As mentioned above, these flaps could also not be thermally welded, but fixed purely through the adhesive with which each adhesive sheet E is provided. In this way a more regular pack is obtained, as the formation of creases due to the thermal effect of the welding unit 1A is avoided. Moreover, the power required for welding is saved.

When, instead, the folded and overlapped flaps F2 are thermally welded with the welding unit 1A, the adhesive sheets E still have the function of improving the aesthetic appearance of the pack C, of masking any imperfections such as holes, and of protecting the welded flaps from possible damage, made more likely by the presence of creases generated by the temperature on the wrapping sheet Fl.

The presence of the adhesive sheets E on one and preferably on both the substantially flat and opposite faces of the pack C allows this latter to be provid- ed with writing, decorations, brands or the like on all the faces, even where the weld between folded and overlapped flaps F2 prevents printing of the wrapping sheet Fl.

In the embodiment of Figs.3A-3H the size H of the wrapping sheet is such that the folded flaps on the two flat faces of the pack C are overlapped. This is particularly suitable in the case in which the wrapping sheet is closed by welding, before applying the two adhesive sheets E to the two substantially flat opposite faces of the pack. In other embodiments the wrapping sheet Fl can have a size H smaller than that illustrated in Figs. 3A-3H. In this case the two substantially flat and opposite faces are not completely covered by the wrapping sheet, but have a free area. An embodiment of this type is shown in Fig.4. Reference Z indicates a central area of the substantially flat face visible in Fig. 4, not covered by the wrapping sheet Fl. The pack C is completed by applying the two adhesive sheets E, which can advantageously have a perimeter surface provided with glue and a central surface without glue. In Fig. 4 the reference CI indicates a perimeter area, in practice forming a frame to which the glue is applied and surrounding an area C2 free of glue. When the adhesive sheet E is applied to the substantially flat face of the pack C, the glued area CI adheres to the wrapping sheet along the perimeter area of the substantially flat face, while the area C2 free of glue remains in contact with the rolls R in the area Z not covered by the wrapping sheet Fl.

In this embodiment, the wrapping sheet is normally not welded, as the overlapping surface of the flaps is insufficient.

The use of a wrapping sheet Fl having a size H smaller than the usual size (Figs. 3A-3H) allows a significant saving of consumable.

In some embodiments the adhesive sheets E can be shaped so as to form a holding handle. Figs. 5A-5F show axonometric views of packs C in which one of the adhesive sheets E forms or secures a handle indicated with the reference M in all the embodiments.

In some embodiments, the adhesive sheet E is folded so as to form one or two areas glued to the pack, from which a portion of sheet, detached from the pack C, projects to form the handle. This portion of sheet can have one or more openings forming a grip. In other embodiments, the handle M is formed by a strip, for example made of plastic film, the ends of which are blocked between the adhesive sheet E and the corresponding substantially flat face of the pack C. In yet other embodiments, the handle is formed by slit in the adhesive sheet E. In this case, the slit can be formed in a central area of the adhesive sheet E without glue, between two glued lateral strips.

In Fig 5 A the adhesive sheet E has two approximately parallel cuts, which define a handle M formed of the same material as the adhesive sheet E. In the area of the handle M, the adhesive sheet E can be free of glue. In Fig. 5B the adhesive sheet has a portion applied adhesively to the substantially flat face of the pack C and a portion free of glue, in which openings defining a grip are formed. Also in this case the handle is formed by the same adhesive sheet E. In Fig. 5C the handle M can be made of a die-cut sheet, to form the apertures defining the grip, which can be glued by means of the adhesive sheet E to the pack C. In Fig. 5D the adhesive sheet E has a central part folded and projecting from the pack, preferably free of glue, forming the holding handle with gripping holes. In variants of embodiment, the handle M can be formed by a folded sheet with two flaps that are inserted between the wrapping sheet of the pack C and a double adhesive sheet E. In Fig. 5E the handle M is formed by a strip of material, the ends of which are folded under the adhesive sheet E, between this latter and the substantially flat face of the pack C. In Fig. 5F the adhesive sheet E has a central area, rectangular in the example illustrated, free of glue, or with a glue that is less adhesive than the one applied in the area surrounding the central area. This latter can be pre-cut along a part of its perimeter: in the example illustrated the central area is rectangular and is pre-cut along three sides. One of the long sides of the perimeter of the central area is integral. In this way the central area of the adhesive sheet E can be detached along three sides and remain adhering to the perimeter area of the adhesive sheet along one of the long sides of the rectangular central area. The flap of adhesive sheet E delimited by the central area can be lifted, as shown in the drawing, and form a handle. The grip can be formed by an incision or by a cut, for example curved, in the raised central portion.

In general, the handle M can be made of the same material that forms the adhesive sheet E. For example, both the handle and the adhesive sheet can be made of paper, or of plastic. When the handle is formed by an element applied by means of the adhesive sheet E but which is not an integral part thereof, as in Fig. 5E, the adhesive sheet E and the handle can be made of different materials, for example the adhesive sheet E can be made of paper and the handle M of plastic, or vice versa.

In general, the adhesive sheet E can have areas glued with different, more or less adhesive glues, to allow repeated opening and closing of the pack C and/or repeated lifting and lowering of the handle formed by the adhesive sheet E.