DEVICE AND METHOD FOR JOINING ENDLESS RAILWAYS

Description

Technical field

[0001] This invention relates to a method and an apparatus for splicing continuous webs, in particular, for the purpose of changing rolls, and is applicable to the field of manufacturing, in particular, in the field of manufacturing smoking articles.Background art

[0002] In the field relevant to this invention, changing from one roll of web to another can be done without interrupting web feed and in such a way that the leading and trailing ends of the webs to be spliced are juxtaposed with each other and joined by an adhesive label. This is done by means of a pressing member which presses the trailing end of the depleted web against the leading end of the replacement web to which one end of the adhesive label has previously been applied, and with the other end left loose.

[0003] The Applicant has, however, observed that this splicing method gives rise to a number of problems, which become apparent especially in the stages of processing the continuous web carried out after splicing.

[0004] Firstly, especially in the case of paper webs of limited thickness, the presence of the adhesive label results in a web with a localized portion that is considerably thicker than the rest of the web. This locally thickened portion may lead to malfunctioning or inefficiency during subsequent processing carried out on the web.

[0005] Secondly, the presence of the adhesive label alters the chemophysical and mechanical properties of the web and may impair the functioning of the processing units located downstream.

[0006] In the field relevant to this invention, the webs can also be spliced by overlapping the respective leading and trailing ends and joining them together with adhesive means, such as glue, for example.

[0007] The Applicant has, however, observed that even in their most recent implementations, the apparatuses configured for making splices of this kind have several disadvantages of a structural, operating and economic / production nature which means that using them is not free of drawbacks. In particular, these apparatuses require complex articulated mechanisms (generally robotized) to grip one of the two ends and overlap it on the other end. The apparatuses thus have a very complex mechanical structure which makes the process overly complicated and increases the costs of their construction and maintenance, and in turn increases the cost of processing the continuous web. Prior art methods and apparatuses are disclosed in US 5,326,419 A, US 5,316,230 A and US 3,995,791 A.Aim of the invention

[0008] In this context, the basic technical purpose of this invention is to provide a method and an apparatus for splicing continuous webs, in particular for the purpose of changing rolls, to overcome the above mentioned disadvantages of the prior art.

[0009] In particular, the aim of this invention is to provide a method and an apparatus for splicing continuous webs, in particular for the purpose of changing rolls, to allow providing a high level of process reliability and, at the same time, to considerably simplify the process and the structure.

[0010] The technical purpose indicated and the aim specified are substantially achieved by a method and an apparatus for splicing continuous webs, in particular for the purpose of changing rolls, comprising the technical features described in claims 1 and 12 and / or in one or more of the claims dependent thereon.Brief description of the drawings

[0011] Further features and advantages of this invention are more apparent in the exemplary, hence non-limiting description of a preferred but non-exclusive embodiment of a method and an apparatus for splicing continuous webs, in particular for the purpose of changing rolls, as illustrated in the accompanying drawings, in which: Figure 1 is a schematic view of a first embodiment of an apparatus for splicing continuous webs according to this disclosure, in a first operating step; Figure 2 is a schematic view of the apparatus of Figure 1, in a second operating step; Figures 3a-3f show an operating sequence of the apparatus of Figures 1 and 2; Figures 4a-4b show an operating sequence of a second embodiment of the apparatus according to this invention; Figures 5a-5f show an operating sequence of a third embodiment of the apparatus according to this invention; Figure 6 is a schematic view of the apparatus of Figures 1 and 2, in a third operating step. Detailed description of preferred embodiments of the invention

[0012] In the accompanying drawings, the reference numeral 1 denotes in its entirety an apparatus for splicing continuous webs, in particular an apparatus for changing rolls, according to this invention.

[0013] In this disclosure, the term "web" is used broadly to denote a strip of material of substantially undefined length, used for a variety of purposes. Preferably, but not exclusively, the term "web" is used to denote a strip of paper for making smoking articles (for making tubular items, outer wrappers of rod-shaped segments or to make the filling of tubular elements, in particular, filling of filter material, or other articles).

[0014] As shown in Figure 1, which represents a first operating condition of the apparatus 1 according to the invention, the apparatus 1 comprises a central support 10, which has two opposite sides 11, 12. The first side 11 has a first supporting surface 11a, configured to supportably and / or slidably receive a first web N1 in such a way that the first web N1 presents a first surface N1a facing towards the central support 10 and a second surface N1b opposite the first surface N1a. In use, the first web N1 is moved along a first feed direction L1. The second side 12 has a second supporting surface 12a, configured to supportably and / or slidably receive a second web N2 in such a way that the second web N2 presents a first surface N2a facing towards the central support 10 and a second surface N2b opposite the first surface N2a. In use, the second web N2 is moved along a second feed direction L2. The expression "supportably and / or slidably" is used to mean the possibility of the web sliding operatively in contact with the respective surface or of the web being operatively detached from it, and coming into contact with it only when the web stops moving for the purpose of splicing.

[0015] Preferably, the two supporting surfaces 11a, 12a of the first and second sides 11, 12 are mirror symmetric about the feed directions L1, L2 of the webs N1, N2 and / or convergent along the feed directions L1, L2 of the webs N1, N2. In other words, in proximity to the central support 10, the first web N1 lies in a first positioning plane, while the second web N2 lies in a second positioning plane, where the two positioning planes are incident.

[0016] Further, the apparatus 1 may comprise guiding means 13 configured for keeping the first web N1 and / or the second web N2 slidably supported against the respective supporting surfaces 11a, 12a of the central support 10. The guiding means 13 are embodied in the form of straps (plate-shaped elements) which can be adjusted to allow a web to be interposed between them and the respective supporting surface 11a, 12a.

[0017] Alternatively, the guiding means 13 can be embodied in the form of rollers or pressing / deflecting members which are suitably positioned and removable to allow a web to be interposed between them and the respective supporting surface 11a, 12a.

[0018] The apparatus 1 comprises positioning means 20, configured for positioning a leading end N2c of the second web N2 at a predetermined receiving position R. In particular, the receiving position R is located downstream of the second supporting surface 12a. The positioning means 20 preferably comprise at least one retaining member 21 (preferably two, one for each web N1, N2) configured to retain and move the leading end N2c of the second web N2.

[0019] The retaining member 21 is configured to securely hold the second surface N1b, N2b of the respective web N1, N2, preferably by air suction applied through a planar contact surface. Preferably, the retaining member 21 is substantially plate-shaped.

[0020] Alternatively, the retaining member 21 is equipped with mechanical means for holding at least the leading end N1c, N2c of the web N1, N2, for example, grippers (in particular, side grippers for gripping facing ends).

[0021] According to an aspect of this invention, the retaining members 21 may be provided with a localized heating system to facilitate drying the glue, as will become clearer as this description continues.

[0022] According to a characteristic aspect of this invention, the apparatus 1 comprises at least one cut-and-press member 40 configured for cutting the first web N1 so as to define a trailing end N1d of the first web N1 and for pressing the trailing end N1d of the first web N1 on the leading end N2c of the second web N2 while the leading end N2c of the second web N2 is positioned at the receiving position R, thereby defining an overlapping splice between the two ends N1d, N2c. Functionally, the cut-and-press member 40 moves the trailing end N1d of the first web N1 from the first positioning plane to the second positioning plane where the leading end N2c of the second web N2 lies.

[0023] In use, the cut-and-press member 40 performs single stroke wherein it moves from a disengaged position (Figure 1), where the cut-and-press member 40 is spaced from the first web N1, through a cutting position, where the cut-and-press member 40 cuts the first web N1, to a pressing position (Figure 2) where the cut-and-press member 40 presses the trailing end N1d of the first web N1 on the leading end N2c of the second web N2. The cutting position is intermediate between the two positions shown in Figure 1 and Figure 2.

[0024] After pressing, splicing of the webs N1, N2 is complete. In this regard, as will become clearer as this description continues, the splicing of the webs N1, N2 may be accomplished by interposing an adhesive means (such as glue, for example) between the two overlapping ends, or by welding the two overlapping ends to each other. In particular, the term "welding" is used to mean slicing performed using heat, ultrasounds, mechanical deformation (knurling) or other methods, as mentioned above, without applying additional substances but by localized deformation of the two webs. Advantageously, the structure and features of the cut-and-press member 40 make the structure of the apparatus 1 considerably compact and uncomplicated.

[0025] The cut-and-press member 40, in particular, has a preferably flat contact surface 40a, configured to come into direct contact with the trailing end N1d of the first web N1 and to move it towards the receiving position R, where the leading end N2c of the second web N2 is located.

[0026] Preferably, the cut-and-press member 40 may be mounted, in particular, rigidly, on a movement wheel 45 configured to move the cut-and-press member 40 between the disengaged and the cutting and pressing positions. Preferably, in the step of moving between the disengaged and the cutting and pressing positions, the cut-and-press member 40 describes an arc-shaped trajectory. Preferably, also, the aforementioned contact surface 40a is positioned radially on the movement wheel 45. Preferably, also, the movement wheel 45 is rotatable about an axis that substantially coincides with an axis of incidence between the planes defined by the supporting surfaces 11a, 12a. Thus, the contact surface 40a is automatically aligned and coplanar with the trailing end N1d of the first web N1 and with the leading end N2c of the second web N2.

[0027] The movement wheel 45 may also be provided with a pair of guiding elements 47 configured to guide and / or tension the respective webs N1, N2. The first web N1 is already interposed between the guiding elements 47 and these then become the transit site of the splice and of the second web N2. Preferably, the guiding elements 47 are two (idle) rollers or, alternatively, two fixed pins defining, between them, a web transit zone and, more preferably, the transit zone substantially coincides with the axis of rotation of the movement wheel 45. The guiding elements 47 thus substantially define a separation between a splicing zone of the webs and a conveying zone of the single web.

[0028] According to this invention, at least one between the first supporting surface 11a and the cut-and-press member 40, preferably the cut-and-press member 40, has a cutting edge 42 such that, while the cut-and-press member 40 is being moved, the interaction between the first supporting surface 11a and the cut-and-press member 40 results in cutting the first web N1 to define the trailing end N1d of the first web N1.

[0029] Figures 3a-3f illustrate an operating sequence of a first embodiment of the apparatus 1 according to this invention.

[0030] In Figure 3a, the first web N1 is moved along the first feed direction L1 until the web N1 is substantially depleted, while the second web N2 is moved along the second feed direction L2 alongside the first web N1 so that the first surface N2a of the second web N2 faces the first surface N1a of the first web N1.

[0031] Preferably, the second web N2 is started along the second feed direction L2 by detaching an initial portion of the second web N2 from a respective roll and feeding the initial portion along the second feed direction L2. Furthermore, the initial portion of the second web N2 may be cut or trimmed as shown in Figure 3a, defining a leading end N2c of the second web N2. Cutting the initial portion of the second web N2 may be carried out by an additional cut-and-press member 41, placed preferably at a position opposite the cut-and-press member 40. In particular, the additional cut-and-press member 41 may have a cutting edge 44 for cutting the second web N2.

[0032] According to an aspect of the invention, the leading end N2c of the second web N2 may be cut transversely to the direction of extension of the second web N2 or at an angle, that is to say, in such a way as to obtain a cut edge that is not perpendicular to the direction of extension of the web. This may be done by providing a respective inclined cutting edge on the additional cut-and-press member 41 and / or on the respective supporting surface or, alternatively, by inclining the entire apparatus 1 by a desired angle relative to the web N2, so that the cutting edges (this time perpendicular) are inclined to the direction of extension of the web N2 by inclining the entire apparatus 1 and, in particular, the central support 10 and the movement wheel 45. In other words, the axis of rotation of the cut-and-press members 40, 41 (hence of the movement wheel 45) is inclined by an acute angle (hence not perpendicular) to the longitudinal axis of extension of the web N2. These specific features described with reference to the cutting of the leading end N2c of the second web N2 also apply to the cutting of the trailing end N1d of the first web N1. Thus, the ends of the webs N1, N2 can both be cut transversely to the direction of extension of the respective web N1, N2 or they may both be inclined or only one of the two may be inclined.

[0033] Preferably, the retaining member 21 is movable by translation towards and away from the respective supporting surface 12a of the central support 10 to position the leading end N2c of the second web N2 at a first position, where it is close to or in contact with the supporting surface 12a, as shown in Figure 3a, and a second position, where it is spaced from the supporting surface and suitable for applying the adhesive means, as explained in more detail as this description continues.

[0034] In the step of cutting, the retaining member 21 positions the leading end N2c of the second web N2 at a cutting position which is preferably retracted relative to the receiving position R.

[0035] Figure 3b represents the (withdrawing) movement away from the receiving position R imparted by the retaining member 21 to the leading end N2c of the second web N2 (after being cut, where necessary). Preferably, the leading end N2c of the second web N2 is moved from the cutting position towards an application zone S where the adhesive means is applied by an applicator member 30 (which may be mounted on the central support 10) at a position between the two supporting surfaces 11a, 12a of the central support 10.

[0036] The applicator member 30 is configured to apply an adhesive means on the first surface N2a of the second web N2 at the leading end N2c of the second web N2. Preferably, the applicator member 30 is a glue nozzle.

[0037] The applicator member 30 defines an application zone S where the applicator member 30 releases the adhesive means on the second web N2. The application zone S is predetermined and defined by a corresponding operating position adopted by the applicator member 30. Preferably, the application zone S is located upstream of the receiving position R relative to a feed direction L2 of the second web N2.

[0038] The retaining member 21 is configured to move the leading end N2c of the second web N2 in controlled manner between the receiving position R and the application zone S, preferably in both directions, for the reasons set out hereinunder.

[0039] The applicator member 30 is switchable at least between a non-operating position and an operating position preferably by rotation about a tilting axis. At the operating position, the applicator member 30 is directed towards the first surface N2a of the second web N2 facing and / or supported by the second supporting surface 12a of the central support 10. At the nonoperating position, the applicator member 30 is positioned at a substantially vertical position. In this regard, there may be a drip container 33 for collecting the adhesive means which drips out of the applicator member 30 by gravity and, if necessary, a scraping or cleaning member (not illustrated).

[0040] Figure 3c shows the adhesive means being applied to the leading end N2c of the second web N2. Functionally, the step of applying an adhesive means may be performed by moving the applicator member 30 and the second web N2 relative to each other at least along the feed direction L2 of the second web N2 towards the receiving position R, preferably describing a linear application path of the adhesive means on the second web N2. Preferably, the application path is between 0.5 cm and 3 cm in length. Still more preferably, the application path is between 1 cm and 2.5 cm in length. In the preferred embodiment, the application path is approximately 2 cm in length. Preferably, the applicator member 30 remains stationary at the application position while the second web N2 is moved by the respective retaining member 21 so that the applicator member 30 can release the adhesive means on the leading end N2c of the second web N2. Alternatively, during application of the adhesive means, the applicator member 30 is moved relative to the second web N2 while the second web N2 remains stationary. Also alternatively, both the applicator member 30 and the second web N2 might be moved relative to each other.

[0041] Figure 3d shows a step of positioning the leading end N2c of the second web N2 at the receiving position R. This step of positioning is accomplished by advancing the leading end N2c of the second web N2 towards the receiving position R. In other words, this step of positioning is accomplished by advancing the leading end N2c of the second web N2 towards the cut-and-press member 40.

[0042] Figure 3e shows a step of cutting the first web N1, in which the trailing end N1d of the first web N1 is defined, and a step in which the trailing end N1d of the first web N1 is pressed on the leading end N2c of the second web N2 at the receiving position R, thereby defining an overlapping splice between the two ends N1d, N2c. In particular, the two ends N1d, N2c are glued to each other by the adhesive means. The pressure applied by the cut-and-press member 40 on the two ends N1d, N2c facilitates their connection.

[0043] Figure 3f shows the two ends N1d, N2c after splicing has been completed and the cut-and-press member 40 has returned to the disengaged position described with reference to Figure 1.

[0044] Figures 4a-4b illustrate an operating sequence of a further embodiment of the apparatus 1 according to this invention.

[0045] In this embodiment, compared to the embodiment described above and illustrated in Figures 3a-3f, the applicator member 30 comprises an applicator roller 35. Preferably, the applicator roller 35 is movable between at least one disengaged configuration, illustrated in Figure 4a, and an operating configuration, illustrated in Figure 4b.

[0046] In the disengaged configuration, illustrated in Figure 4a, the applicator roller 35 is preferably retracted all the way inside the central support 10. Alternatively, in the disengaged configuration, the applicator roller 35 might completely confront the central support 10.

[0047] The applicator roller 35 may receive the adhesive substance from a suitable dispenser 30 and in this case, too, there may be a drip container under the applicator roller 35, to collect the adhesive means.

[0048] Starting from the configuration of Figure 4a in which the leading end N2c of the second web N2 has been cut and withdrawn so it is exactly aligned with or upstream of the applicator roller 35, the leading end N2c is advanced by the retaining member 21 along the supporting surface 12a (that is, along a direction parallel to the supporting surface 12a) and preferably at a distance therefrom, so that the applicator roller 35 can engage the second web N2, causing the applicator roller 35 to roll on the first surface N2a of the second web N2 and to deposit the adhesive substance thereon (Figure 4b). Once the adhesive substance has been applied, the applicator roller 35 is retracted, that is, returned to the disengaged configuration, and the retaining member 21 is advanced towards the guiding surface 12a by a translational or roto-translational movement such as to move the leading end N2c of the second web N2, with the adhesive substance applied thereon, to the receiving position R, where the trailing end N1d of the first web N1 can be pressed on it.

[0049] Preferably, the applicator roller 35 receives a portion 37 of adhesive means to cover a predetermined arc of the applicator roller 35. After the applicator roller 35 has engaged and rolled on the second web N2, the adhesive means is released on the second web N2 so as to release a strip of adhesive of predetermined length (application path). Alternatively, the applicator roller 35 may be covered entirely with the adhesive to perform only part of a turn in contact with the second web N2 so as to release a strip of adhesive of the desired length.

[0050] Preferably, in this case too, the application path is between 0.5 cm and 3 cm in length, preferably between 1 and 2.5 cm in length and, still more preferably, around 2 cm in length.

[0051] The other steps in the process of splicing the webs N1, N2 do not substantially differ from those described above with reference to the embodiment of Figures 3a-3f and are not therefore described in further detail.

[0052] Figures 5a-5f illustrate an operating sequence of a further embodiment of the apparatus 1 according to this invention.

[0053] In particular, in Figure 5a, the first web N1 is moved along the first feed direction L1 until the web N1 is substantially depleted, while the second web N2 is moved along the second feed direction L2 alongside the first web N1.

[0054] Preferably, the initial portion of the second web N2 may be cut or trimmed by the additional cut-and-press member 41 to define a leading end N2c of the second web N2.

[0055] Figure 5b represents the movement imparted by the retaining member 21 to the leading end N2c of the second web N2 away from the receiving position R and towards an application zone S where the applicator member 30 applies the adhesive means.

[0056] In this embodiment, the applicator member 30 is spaced from the central support 10 and acts only on the second web N2. Furthermore, the retaining member 21 is configured to move the leading end N2c of the second web N2 towards the application zone S of the adhesive means by deflecting the leading end N2c of the second web N2 in such a way as to position the leading end N2c at or upstream of the applicator member 30, in particular by deflecting the leading end N2c along a trajectory transverse to a positioning plane of the leading end N2c of the second web N2, more specifically a curved or arcuate trajectory.

[0057] Functionally, the step of applying an adhesive means may be performed by moving the applicator member 30 and the second web N2 relative to each other. In particular, the retaining member 21 remains substantially stationary while the applicator member 30 is moved and preferably describes a linear application path, transverse to the second web N2, along which the adhesive means is applied on the second web N2. The application path is between 0.1 mm and 30 mm in length, preferably between 0,5 mm and 20 mm in length and, still more preferably, between 1 mm and 10 mm in length. Alternatively, the retaining member 21 remains substantially stationary while the applicator member 30 is moved and preferably describes a linear application path, longitudinal to the second web N2, along which the adhesive means is applied on the second web N2. Preferably, in this case, the application path is between 0.5 cm and 3 cm in length, preferably between 1 and 2.5 cm in length and, still more preferably, around 2 cm in length.

[0058] Figures 5c and 5d show a movement of the leading end N2c of the second web N2 from the application zone S to the receiving position R.

[0059] Figure 5e shows the steps of cutting and pressing the trailing end N1d of the first web N1 on the leading end N2c of the second web N2.

[0060] Lastly, Figure 5f shows a step of moving the cut-and-press member 40 to the disengaged position.

[0061] In variants not illustrated, the apparatus 1 is configured to splice the webs without applying an adhesive means. In these solutions, splicing the ends of the webs is accomplished by welding the overlapping ends of the first and the second web.

[0062] For example, there may be welding devices integrated in and / or connected to the cut-and-press member and / or to the positioning means so that after the trailing end of the first web is pressed onto the leading end of the second web, the welding devices can weld the two ends to each other. This type of weld can be made more efficient by a pressing action applied by the cut-and-press member on the positioning means.

[0063] As shown in Figure 6, the apparatus 1 according to this invention may have a structure that is substantially mirror symmetric about a main axis of extension A. Advantageously, this technical feature allows the apparatus 1 to operate fully automatically and efficiently.

[0064] In effect, advantageously, in the embodiments where the apparatus 1 is symmetric or mirror symmetric, it is able to splice the two webs repeatedly and in both directions, hence in sequence in one direction and the other, which means the apparatus 1 can be used for an indefinite number of roll changes and splices.

[0065] In other words, after the first web N1 has been spliced to the second web N2 and after the second web N2 is depleted, the second web N2 can be spliced to a third web N1', guided in the same way as the first web N1 using components that are mirror symmetric to those described above forming part of the apparatus 1, as will become clearer as this description continues. Thus, it is possible to automatically and serially splice a plurality of webs N1, N2, N1', the rolls of which are loaded by an operator manually or by automated means upstream of the apparatus 1.

[0066] According to this invention, at structural level, the apparatus comprises a pair of cut-and-press members 40, 41 opposite each other and each configured to cut a first or second web N1, N2 and to press the trailing end N1d, N2d of the web N1, N2 on the leading end N2c, N1c of the other web N2, N1. For each of the webs N1, N2, there is a respective receiving position R, intended for positioning the leading end N1c, N2c of the respective web N1, N2. In particular, during a splicing operation, the receiving positions R are located substantially mirror-symmetrically about the main axis of extension A.

[0067] The cut-and-press members 40, 41 are substantially identical and positioned mirror symmetrically to each other. In particular, both have a respective, preferably flat contact surface 40a, 41a configured to come into direct contact with the trailing end N1d, N2d of the respective web N1, N2 and to move it towards the receiving position R, where the leading end N2c, N1c of the other web N2, N1 is located.

[0068] The cut-and-press members 40, 41 are mounted, in particular rigidly, on the same movement wheel 45, configured for moving each cut-and-press member 40, 41 between the respective disengaged and pressing positions. Alternatively, in an embodiment not illustrated, the apparatus 1 may comprise a single cut-and-press member 40 having two respective opposite contact surfaces configured to come into direct contact with the trailing end N1d, N2d of the respective web N1, N2 and to move it towards the receiving position R, where the leading end N2c, N1c of the other web N2, N1 is located.

[0069] Described below are further structural features of the apparatus 1 when its structure is symmetrical or mirror symmetrical.

[0070] With reference to Figures 3a-3f, when the apparatus 1 has a symmetrical or mirror symmetrical structure, the applicator member 30 is switchable at least between a first operating position, where it is directed towards the first surface N1a of the first web N1 facing and / or supported by the first supporting surface 11a, and a second operating position, where it is directed towards the first surface N2a of the second web N2 facing and / or supported by the second supporting surface 12a, preferably by rotation about a tilting axis. Further, the positioning means 20 comprise two retaining members 21, disposed on opposite sides of the central support 10 and each configured to retain at least the leading end N1c, N2c of the respective web N1, N2.

[0071] Further, the positioning means 20 comprise, on each side of the central support 10, a respective retaining member 21, configured to move the leading end N1c, N2c of the respective web N1, N2 away from the receiving position R towards the adhesive application zone S, and vice versa, in particular by a translational or rototranslational movement.

[0072] With reference to Figures 4a-4b, when the apparatus 1 has a symmetrical or mirror symmetrical structure, it comprises an applicator roller 35 which is configured to adopt two distinct operating configurations so as to selectively engage the first web N1 or the second web N2. Depending on the operating configuration adopted, the applicator roller 35 is moved in a first rotation direction or in a second rotation direction, opposite of the first rotation direction. The applicator roller 35 also has an intermediate position where it is preferably retracted all the way inside the central support 10.

[0073] In this embodiment, too, the positioning means 20 comprise, on each side of the central support 10, a respective retaining member 21, configured to move the leading end N1c, N2c of the respective web N1, N2 away from the receiving position R towards the adhesive application zone S, and vice versa, in particular by a translational or rototranslational movement.

[0074] With reference to Figures 5a-5f, when the apparatus 1 has a symmetrical or mirror symmetrical structure (preferred embodiment), it comprises, on each side of the central support 10, an applicator member 30 that is spaced from the central support 10 and acts only on one respective web N1, N2. In other words, the applicator members 30 are disposed on opposite sides of the central support 10 and each is configured to release the adhesive means on the first surface N1a, N2a of a respective web N1, N2. Further, the positioning means 20 comprise, on each side of the central support 10, a respective retaining member 21, configured to move the leading end N1c, N2c of the respective web N1, N2 away from the receiving position R towards the adhesive application zone S, and vice versa, in particular by a translational or rototranslational movement, in other words, therefore, by deflecting the respective web N1, N2 out of its positioning plane.

[0075] The invention achieves the above-mentioned aims by eliminating the drawbacks of the prior art: in this regard, it should be noted, first of all, that the apparatus 1, as described and / or claimed herein, allows the webs to be efficiently spliced and, at the same time, has an uncomplicated, high-performance structure that allows reducing the production and maintenance charges of the apparatus, thus reducing the production costs of the continuous web.

[0076] This result is achieved especially thanks to the compact structure of the cut-and-press member which allows the webs to be cut and pressed together in a single stroke.

[0077] It should also be noted that this result is achieved thanks to the symmetrical or mirror symmetrical structure of the apparatus 1 which allows joining a plurality of webs in series automatically.

Claims

1. A method for splicing continuous webs, in particular when changing rolls, comprising the following steps: (a) moving a first web (N1) along a first feed direction (L1), where the first web (N1) has a first surface (N1a) and a second surface (N1b), opposite the first surface (N1a); (b) moving a second web (N2), having a first surface (N2a) and a second surface (N2b), opposite the first surface (N2a), along a second feed direction (L2) alongside the first web (N1) so that the first surface (N2a) of the second web (N2) confronts the first surface (N1a) of the first web (N1); (c) applying an adhesive means on the first surface (N2a) of the second web (N2) at a leading end (N2c) of the second web (N2); the step (c) applying the adhesive means being performed by an applicator member (30); (d) placing the leading end (N2c) of the second web (N2) at a predetermined receiving position (R); (e) cutting the first web (N1) to define a trailing end (N1d) of the first web (N1); (f) pressing the trailing end (N1d) of the first web (N1) on the leading end (N2c) of the second web (N2) at the receiving position (R), thereby defining an overlapping splice; characterized in that the step (e) of cutting the first web (N1) and the step (f) of pressing the first web (N1) are performed during a single stroke of the same cut-and-press member (40) moving from a disengaged position, where the cut-and-press member (40) is spaced from the first web (N1), through a cutting position, where the cut-and-press member (40) cuts the first web (N1), to a pressing position, where the cut-and-press member (40) presses the trailing end (N1d) of the first web (N1) on the leading end (N2c) of the second web (N2).

2. The method according to claim 1, wherein the step (c) of applying an adhesive means is performed by moving the applicator member (30) and the second web (N2) relative to each other at least along the feed direction (L2) of the second web (N2) towards the receiving position (R), in particular, describing a linear application path of the adhesive means on the second web (N2); preferably, the application path having a length of between 0.5 cm and 3 cm, the application path, more preferably, having a length of between 1 and 2.5 cm and, still more preferably, of around 2 cm.

3. The method according to claim 1 or 2, wherein the step (d) of placing the leading end (N2c) of the second web (N2) at the receiving position (R) is carried out by detaching an initial portion of the second web (N2) from a respective roll, feeding the initial portion towards the receiving position (R) and cutting the initial portion to define the leading end (N2c); the initial portion of the second web (N2) being preferably cut by an additional cut-and-press member (41) being preferably disposed at a position opposite and / or mirror symmetrical to the cut-and-press member (40).

4. The method according to claim 1 or 2 or 3, wherein the step (c) of applying an adhesive means on the first surface (N2a) of the second web (N2) is preceded by a step (g) of moving the leading end (N2c) of the second web (N2) away from the receiving position (R) towards an application zone (S) of the adhesive means.

5. The method according to claim 4, wherein the step (g) of moving the leading end (N2c) of the second web (N2) away from the receiving position (R) towards an application zone (S) of the adhesive means is carried out by retracting the leading end (N2c) of the second web (N2), preferably along the feed direction (L2), by a predetermined distance such as to position the leading end (N2c) at or upstream of the applicator member (30).

6. The method according to claim 4, wherein the step (g) of moving the leading end (N2c) of the second web (N2) away from the receiving position (R) towards an application zone (S) of the adhesive means is carried out by deflecting the leading end (N2c) of the second web (N2) in such a way as to position the leading end (N2c) at or upstream of the applicator member (30), in particular by deflecting the leading end (N2c) along a trajectory transverse to a positioning plane of the leading end (N2c), more specifically a curved or arcuate trajectory.

7. The method according to any one of the preceding claims, wherein the step (d) of placing the leading end (N2c) of the second web (N2) at the predetermined receiving position (R) is performed by supporting the leading end (N2c) with a retaining member (21), in particular comprising a plate-shaped positioning support, preferably in contact with the second surface (N2b) of the second web (N2); the retaining member (21) defining a supporting anvil for the cut-and-press member (40) during the step (f) of pressing.

8. The method according to claim 7 when dependent on claim 4 or 5 or 6, wherein the step (g) of moving the leading end (N2c) of the second web (N2) away from the receiving position (R) towards an application zone (S) of the adhesive means is carried out by the retaining member (21).

9. The method according to any one of the preceding claims, wherein an additional cut-and-press member (41) is provided for cutting the second web (N2) to define a trailing end (N2d) of the second web (N2) and, during the same movement, pressing the trailing end (N2d) of the second web (N2) on the leading end (N1'c) of a third web (N1') placed at a corresponding receiving position (R) to define an overlapping splice; the third web (N1') being guided so it follows the same trajectory as the first web (N1).

10. The method according to claim 9, wherein the cut-and-press members (40, 41) are moved in alternating manner according to the same laws of motion to define corresponding mirror symmetrical, sequential splices on the webs (N1, N2).

11. The method according to any one of the preceding claims, wherein the step (d) of applying an adhesive means is performed by switching the applicator member (30) from a non-operating configuration to an operating configuration.

12. An apparatus (1) for splicing continuous webs, in particular a roll changing apparatus, comprising: - a central support (10) having two opposite sides (11, 12), a first side (11) of the sides (11, 12) having a first supporting surface (11a), configured to supportably and / or slidably receive a first web (N1) in such a way that the first web (N1) presents a first surface (N1a) facing towards the central support (10) and a second surface (N1b) opposite the first surface (N1a), the second side (12) of the two sides (11, 12) having a second supporting surface (12a), configured to supportably and / or slidably receive a second web (N2) in such a way that the second web (N2) presents a first surface (N2a) facing towards the central support (10) and a second surface (N2b) opposite the first surface (N2a); - positioning means (20), configured for positioning a leading end (N2c) of the second web (N2) at a predetermined receiving position (R), where the receiving position (R) is, in particular, located downstream of the second supporting surface (12a); - at least one applicator member (30), configured to apply an adhesive means on the first surface (N2a) of the second web (N2) at the leading end (N2c) of the second web (N2); characterized in that it comprises at least one cut-and-press member (40) configured for cutting the first web (N1) so as to define a trailing end (N1d) of the first web (N1) and for pressing the trailing end (N1d) of the first web (N1) on the leading end (N2c) of the second web (N2) at the receiving position (R), thereby defining an overlapping splice between the two ends (N1d, N2c); the cut-and-press member (40) performing a single stroke wherein it moves from a disengaged position, where the cut-and-press member (40) is spaced from the first web (N1), through a cutting position, where the cut-and-press member (40) cuts the first web (N1), to a pressing position, where the cut-and-press member (40) presses the trailing end (N1d) of the first web (N1) on the leading end (N2c) of the second web (N2).

13. The apparatus (1) according to claim 12, wherein at least one between the first supporting surface (11a) and the cut-and-press member (40), preferably the cut-and-press member (40), has a cutting edge (42) such that the interaction between the first supporting surface (11a) and the cut-and-press member (40) results in cutting the first web (N1) to define the trailing end (N1d) of the first web (N1).

14. The apparatus (1) according to claim 12 or 13, having a structure that is substantially mirror symmetrical about a main axis of extension (A) and comprising a pair of cut-and-press members (40, 41), mounted opposite each other and each being configured to cut a respective first or second web (N1, N2) and pressing the trailing end (N1d, N2d) of the web on the leading end (N1c, N2c) of the other web; wherein, for each of the webs (N1, N2), there is a respective receiving position (R), intended for positioning the leading end (N1c, N2c) of the respective web (N1, N2) during splicing; the receiving positions being substantially mirror symmetrical about the main axis of extension (A).

15. The apparatus (1) according to claim 14, wherein the cut-and-press members (40, 41) are mounted, in particular rigidly, on the same movement wheel (45), configured for moving each cut-and-press member (40, 41) between the disengaged and pressing positions.

16. The apparatus (1) according to any one of claims from 12 to 15, wherein: the at least one applicator member (30), preferably mounted on the central support (10), defines an application zone (S) where the applicator member (30) releases the adhesive means on the second web (N2); the application zone (S) is located upstream of the receiving position (R) relative to a feed direction (L2) of the second web (N2); the positioning means (20) comprise at least one retaining member (21), configured to retain at least the leading end (N2c) of the second web (N2) and to move the leading end (N2c) of the second web (N2) between the receiving position (R) and the application zone (S).

17. The apparatus (1) according to claim 16, when dependent on claim 14, comprising a single applicator member (30) switchable at least between a first operating position, where it is directed towards the first surface (N1a) of the first web (N1) facing the first supporting surface (11a), and a second operating position, where it is directed towards the first surface (N2a) of the second web (N2) facing the second supporting surface (12a), preferably by rotation about a tilting axis; the positioning means (20) comprising two retaining members (21), disposed on opposite sides of the central support (10) and each being configured to retain at least the leading end (N1c, N2c) of the respective web (N1, N2).

18. The apparatus (1) according to claim 16, or 17, wherein the single or each retaining member (21) is movable towards and away from the respective supporting surface (11a, 12a) of the central support (10) to position the leading end (N1c, N2c) of the respective web (N1, N2) at a first position, where it is close to or in contact with the supporting surface (11a, 12a), and a second position, where it is spaced from the supporting surface (11a, 12a) and suitable for applying the adhesive means.

19. The apparatus (1) according to any one of claims from 12 to 15, wherein the at least one applicator member (30) is spaced from the central support (10) and wherein the positioning means (20) comprise at least one retaining member (21), configured to move the leading end (N2c) of the second web (N2) away from the receiving position (R) towards an application zone (S) for applying the adhesive means, in particular by a rotational or roto-translational movement.

20. The apparatus (1) according to claim 19 when dependent on claim 14, comprising two applicator members (30), disposed on opposite sides of the central support (10) and each being configured to release the adhesive means on the first surface (N1a, N2a) of a respective web (N1, N2); and wherein the positioning means (20) comprise two retaining members (21), disposed on opposite sides of the central support (10) and each being configured to retain at least the leading end (N1c, N2c) of the respective web (N1, N2) and to move the respective leading end (N1c, N2c) between the receiving position (R) and the application zone (S) for applying the adhesive means.