Machine for producing web material and associated winding method

Abstract

A machine (1, 101) for producing web material and an associated winding method are described. The machine (1, 101) comprises: at least a first winding roller (11) and a second winding roller (21) rotatably mounted about a first axis of rotation (10) and a second axis of rotation (20), respectively; at least a first pressure roller (31) and a second pressure roller (41) designed to rotate about a third axis of rotation (30) on the first movable arm (32) and about a fourth axis of rotation (40) on the second movable arm (42), respectively. These rollers (11, 21, 31, 41) define a winding channel (7) for winding a paper web (6) around a core (5 ', 5' ', 105', 105 '') to form a web wherein the core rotates around an associated axis of rotation (50 ', 50' ', 150', 150 ''). The core (5 ', 5' ', 105', 105 '') is designed to move, under the action of one or more rollers (11, 21, 31, 41), between an initial position for winding the web (6) and a final position for discharging the completely wound roll, initially alone and then together with the continuously increasing web. The winding rollers (11, 21) are located on opposite sides of the winding channel (7) with respect to the compression rollers (31, 41), respectively upstream and downstream of the channel (7) with respect to the movement of the core (5 ', 5' ', 105', 105 '') during winding. The two movable arms (32, 42) pivot about the first secondary axis of rotation (30) and the second secondary axis of rotation (40), respectively, such that rotation of the first movable arm (32) and / or the second movable arm (42) moves the first compression roller (31) and / or the second compression roller (31) away from or towards the first winding roller (11) and / or the second winding roller (21). A significant feature of the machine (1, 101) is that, in an initial position, the at least three rollers (11, 21, 31, 41) are designed to simultaneously control the web wound around the core (5 ', 5' ', 105', 105 '') and to cut the paper web (6) until the desired roll is formed.

Description

Technical Field

[0001] The invention relates to a machine for producing web material and to a related winding method. Background Art

[0002] So-called "winders" are designed to produce web (or roll) material, e.g. rolls of "tissue" type paper, such as kitchen rolls, toilet rolls, etc., which unwind a paper web from an original reel in order to wind the paper web onto a reel (also called a "stick" or "roll") which is then used for subsequent processing to produce rolls of paper for domestic use.

[0003] There are various types of rewinders on the market, mainly based on a separation device that slows down the web during paper unwinding, when a new paper roll has been wound, causing a break and allowing unloading of the wound paper roll and loading of a new core to be wound.

[0004] Typically, the rewinder comprises: a unit for driving the web to be wound, and a winding unit driven by a motor located downstream in the web advancing direction, the winding unit being designed to wind the paper web fed by the traction unit around a tubular winding core to form a paper roll of desired size.

[0005] A known type of winding unit comprises: a main roller and an auxiliary roller rotating in contact with the core being wound, and at least one pressure unit equipped with a pressure roller, a so-called press, which rotates in contact with the paper roll being formed. The press can be remote from the main roller and the auxiliary roller, for example by a rotating arm.

[0006] A machine of this type is known from patent application EP 3 601 122 and comprises: a drive unit for feeding a paper web; a paper roll winding unit; main and auxiliary rollers which rotate in contact with the core being wound; two pressure units, each of which is equipped with a rotating pressure roller on the paper roll being formed; a system for loading the cores to be wound, which introduces a new core while discharging the formed paper roll; and a separating device for interrupting the continuity of the paper web at the end of the winding cycle and then rewinding the paper web on the new core introduced.

[0007] According to this embodiment, the pressure unit comprises two motor-driven pressure rollers, also called presses, which are arranged to be alternately positioned relative to the paper roll so as to rotate while being in contact with the paper roll being formed at least during a part of the winding step, both with a peripheral speed substantially equal to the winding speed of the web.

[0008] According to the rewinding machine described in the prior art, the core is inserted into a winding channel defined by two rollers (a primary roller and an auxiliary roller). The core is in contact with these two rollers during the initial start-up step: after reaching a certain diameter, the first press comes into contact with the growing roll, and subsequently, the second press also starts to apply pressure.

[0009] In the last part of the winding step, the paper roll is enlarged in simultaneous contact with both presses and the main rollers.

[0010] At the end of the winding step, an interrupter separates the web, while the two presses continue to rotate and remain in contact with the paper reel.

[0011] In this system, the interruption step is carried out by means of a pneumatic distribution device or, alternatively, by applying an acceleration to the press: at the point of contact with the press, the peripheral speed of the web on the reel is increased relative to the preset forward speed of the reel, which in fact induces a tension in the upstream portion of the web, which therefore breaks and interrupts the continuity of the web at the pre-cut generally provided along the extension of the web.

[0012] Finally, the formed log is discharged and a new core is inserted into the winding channel for winding.

[0013] This machine is very efficient, but it also has certain problems and disadvantages.

[0014] At the beginning of the winding step of the roll, the roll is controlled by only two rolls, the main roll and the secondary roll. This leads to an unstable winding process, especially in this step, which may cause web breaks. This problem can be overcome by adjusting the speed of the secondary roll, so that the speed of the secondary roll can be appropriately varied and controlling its opening relative to the main roll (that is, by adjusting the distance between the two rotation centers of the main roll and the secondary roll).

[0015] Especially for paper rolls with very large final diameters, the exchange control between the press rolls is a crucial step.

[0016] To manage the winding, the profile of the secondary roller must be specifically controlled, customized to the product.

[0017] In other words, to optimize the efficiency of the machine, the parameters of the secondary rollers' speed of rotation and opening must be varied according to the specifications of the rolls to be manufactured (e.g. core diameter and final diameter of the finished roll, length, winding, paper thickness, etc.).

[0018] Purpose of the Invention

[0019] The present invention aims to overcome the above-mentioned disadvantages of the prior art machines for producing web material and the related winding methods, by allowing a firm clamping by the press, thus ensuring a more stable method of winding the web.

[0020] In the context of the above-mentioned aims, an object of the present invention is to improve the reliability and efficiency of winding, in particular during the initial steps of winding a paper roll, so as to facilitate the management of control parameters.

[0021] Another object of the present invention is to provide a machine for producing web material and a relative winding method which employs devices easily available on the market and uses commonly available materials, thus making the device economically competitive. Summary of the invention

[0022] This object, as well as these and other objects which will be described in more detail below, can be achieved by a machine for producing web material and a related winding method according to the invention comprising the technical features described in one or more of the appended claims. The dependent claims correspond to different possible embodiments of the invention.

[0023] In particular, according to a first aspect, the invention relates to a machine for producing roll paper material which, by simultaneously controlling three of the four rolls with which it is equipped (two for winding and two for pressing), ensures extremely high stability of the system, limiting or even eliminating dangerous vibrations and instabilities generated in the first step of winding the roll, which vibrations could endanger the integrity of the paper web wound on the core used to form the roll.

[0024] Preferably, this contact action, which is simultaneously applied by at least three rollers with which the machine is equipped, is always ensured between the initial position and the cutting of the web, that is to say during the winding of the paper around the paper reel.

[0025] In other words, the machine for producing web material according to the invention comprises: at least a first winding roller and a second winding roller, each of which is rotatably mounted about a first rotation axis and a second rotation axis, respectively, and at least a first pressure roller and a second pressure roller, each of which is designed to rotate about a third rotation axis located on a first movable arm and a fourth rotation axis located on a second movable arm, respectively. The at least four rollers define a passage for a winding web, which is intended to be wound on a core in a continuously rotating manner, initially alone and then together with the growing web, pivoting about the rotation axis to form a roll. The winding rollers are positioned on opposite sides of the winding passage relative to the pressure rollers, respectively upstream and downstream of the winding passage relative to the movement of the core in the passage during winding. The core is designed to be moved between an initial winding position and a final position of the web (6) by the action of one or more of the winding rollers and the pressure roller. The two movable arms pivot about the first secondary rotation axis and the second secondary rotation axis respectively, so that their rotation moves the first and / or second pressure rollers toward or away from the first and / or second winding rollers. The at least three rollers are designed to simultaneously control the web wound around the core between the initial position of the passage until the paper web wound around the core is suitable for cutting, the initial position of the passage being when at least the center line of the core has exceeded the axis connecting the rotation centers relative to the winding rollers, or even more preferably when the outermost periphery of the core is tangent to the connecting line and its center line has exceeded the axis.

[0026] The second feature of the invention relates to the "V" shape of the first movable arm, which is mainly due to the fact that the applicant has positioned the first secondary rotation axis of the second arm so that it moves in a half plane determined by the connecting line of the two rotation centers of the winding roller and opposite to the winding channel, so as to allow the first pressure roller to swing in such a way as to allow improved control of the paper roll in the initial step.

[0027] Another aspect of the invention relates to a winding method for forming a paper web by such a rewinding machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Further features and advantages of the invention will become more apparent in the following detailed description with reference to a preferred, non-limiting embodiment of a machine for producing web material and a related winding method, shown by way of example and without limiting the scope of the invention, with the aid of the accompanying drawings, in which:

[0029] Figures 1 to 10 Schematically shows the arrangement of winding rollers 11 and 21 and pressing rollers 31 and 41 during the movement and formation of a log wound around a core 5 ′ and 5 ″ in a winding method in a machine 1 for producing web material;

[0030] Figures 11 to 21Schematically shows the arrangement of rollers 11, 21, 31 and 41 during the movement and formation of logs wound around cores 105' and 105" in a winding method in a machine 101 for producing web material; in particular, Fig.11A Shows Fig.11 Details;

[0031] Fig. 22 The shape of the first arm 32 is schematically shown in plan view;

[0032] Fig.23A and Fig. 23B The upstream and downstream limits of the winding channel 7 are each schematically indicated. DETAILED DESCRIPTION

[0033] The above-mentioned figures show a preferred embodiment of a machine for producing web material and a related winding method according to the invention, which machine is generally indicated by reference 1 or 101 and comprises at least four rollers: a first winding roller 11, a second winding roller 21, a first pressing roller 31 and a second pressing roller 41, the first winding roller 11 and the second winding roller 21 being rotatably mounted about a first rotation axis 10 and a second rotation axis 20, respectively; the first pressing roller 31 and the second pressing roller 41 being designed to rotate about a third rotation axis 30 located on a first movable arm 32 and a fourth rotation axis 40 located on a second movable arm 42, respectively. These four rollers 11, 21, 31 and 41 define a winding channel 7 for the winding of a paper web 6 around a core 5', a core 5", a core 105' or a core 105" to form a log, wherein the core 5', a core 5", a core 105' or a core 105" rotates about a corresponding rotation axis 50', a rotation axis 50", a rotation axis 150' and a rotation axis 150". The two winding rollers 11 and 21 are located on opposite sides of the winding channel 7 relative to the two pressing rollers 31 and 41, respectively upstream and downstream of the winding channel 7 relative to the unwinding of the cores 5', 5", 105' and 105" during winding.

[0034] It will be apparent that cores 5', 5", 105' and 105" initially rotate on their own about axis 50', 50", 150' and 150", but then rotate with the drum as it grows.

[0035] Therefore, in this sense, the web 6 comes from an upstream point of the passage 7. The first movable arm 32 and the second movable arm 42 are pivotable about the first secondary rotation axis 30 and the second secondary rotation axis 40, respectively, so that the rotation of the first movable arm 32 and / or the second movable arm 42 moves the first pressure roller 31 and / or the second pressure roller 31 away from or towards the first winding roller 11 and / or the second winding roller 21: obviously, if the first movable arm 32 is rotated, it will allow the first pressure roller 31 to move towards or away from one of the winding rollers 11 or 21, and vice versa, the rotation of the second movable arm 42 will cause the second pressure roller 41 to move towards or away from one of the winding rollers 11 or 21.

[0036] The roll formed on the core 5', core 5", core 105' and core 105" is controlled between an initial position and a final position by one or more of the rollers 11, 21, 31 and 41, wherein the initial position corresponds to the winding area of ​​the paper roll and the final position corresponds to the discharge area 9 of the formed roll.

[0037] In particular, the initial position starts from the moment when at least the center line of the core 5', core 5", core 105' or core 105" passes through the axis K connecting the rotation center C1 and the rotation center C2 related to the roller 11 and the roller 21, and even more preferably, when the outermost contour of the core 5', core 5", core 105' or core 105" is tangent to the connecting line K (and its center line has passed through this theoretical line), as shown in FIG. Fig.23A shown.

[0038] The term "winding channel 7" refers to a portion of the area delimited by the four rollers 11, 21, 31 and 41, which winding channel is defined upstream with respect to the movement of the paper roll by the connecting line K, immediately after the channel 8 for introducing the core 5', core 5", core 105' or core 105" to be wound (upstream limit); and downstream by the line H connecting the center of rotation C2 and the center of rotation C4 of the rollers 21 and 41, immediately before the discharge area 9 of the formed roll (downstream limit, Fig. 23B ).

[0039] The main feature of the machine according to the invention is that, in the initial position, at least three between the first winding roller 11 and the second winding roller 21 and the first pressure roller 31 and the second pressure roller 41 simultaneously control the web of paper wound around the core 5', core 5", core 105' or core 105", and the machine always ensures the contact effect of at least three of the rollers 11, roller 21, roller 31 and roller 41 between this initial position and the cutting of the paper web 6.

[0040] Preferably, in the initial winding position the core 5', 5", 105' or 105" has no paper layer wound around its own axis of rotation 50', 50", 150' or 150", whereas in the final position the log is fully wound.

[0041] Advantageously, in the initial position, the first winding roller 11, the second winding roller 21 and the first pressing roller 31 simultaneously control the web of paper wound around the core 5', the core 5" or the core 105", while for the core 105' which is also in the initial position, it is controlled simultaneously by the second winding roller 21, the first pressing roller 31 and the second pressing roller 41.

[0042] This synergy makes the machine extremely stable during the discharge of the finished rolls (that is to say when the old roll leaves the winding area), completely wound around the first cores 5' and 105' and the new cores 5" and 105".

[0043] Advantageously, in the final position, the second winding roller 21 and the second pressure roller 41 simultaneously control the already formed web wound around the core 5', core 5", core 105' or core 105" to accompany the discharge of the web, thus allowing the paper roll just facing the winding channel 7 to be "handled" by the three rollers (in particular the winding rollers 11 and 21 and the pressure roller 31).

[0044] During implementation, the second winding roller 21 and the second pressing roller 41 simultaneously control the web of paper in the final position wound around the first core 5' or the first core 105', and at the same time, the first winding roller 11, the second winding roller 21 and the first pressing roller 31 simultaneously control the web of paper in the initial position wound around the second core 5' and the second core 105'.

[0045] In order to facilitate the introduction of the second core 5″ or 105″ at the same time when the first core 5′ or 105′ has completed its winding and is ready to be discharged from the passage 7 as a formed web, the first movable arm 32 is advantageously rotated about the first secondary rotation axis 30 to allow the sliding of the first press roller 31 on the core 5″ or 105″ along the winding passage 7. The gradual movement of the press 31 (i.e. the sliding of the kind just described) prevents sudden movements of the system and improves the stability of the machine, which could cause harmful vibrations due to the fragile state of the paper web 6 to be wound.

[0046] In this regard, the Applicant understands that by moving the first axis of rotation 30 of the arm 32 into a half-plane defined by the line K connecting the two centers of rotation C1 and C2 of the rollers 11 and 21 and opposite the winding channel 7, the first press 31 can be swung, thereby allowing improved control of the paper roll in the initial steps.

[0047] refer to Figure 1 To implement this configuration, due to the size of the primary roller 11 and the secondary arm 42, the applicant must shape the arm 32 into a substantially "V" shape.

[0048] Advantageously, the "V" shape is formed in such a way that the angle Z is limited by the contact of the symmetry axis S31 and the symmetry axis S30 of the ends 32A and 32B of the arms at the pressure roller 31 and the rotation axis 30 respectively (and passing through the axis 30 and the center C3), so that the angle Z is 40° to 80° (including 40° and 80°), preferably 45° to 70° (including 45° and 70°), more preferably 50° to 65° (including 50° and 65°), and even more preferably 53° to 60°.

[0049] For practical purposes, the arm 42 is also made in a conventional manner. The purpose of the latter is to provide good control of the paper roll during the final winding step, i.e. when the paper roll enters the discharge area 9.

[0050] In the above-mentioned rewinding machine 1 or rewinding machine 101, the method of winding paper around a paper roll to produce a web material comprises the following steps:

[0051] - introducing the first core 5 ′ or the first core 105 ′ into the winding channel 7 ,

[0052] - winding the paper web 6 coming from the introduction channel 8 upstream of the winding channel 7 on the first core 5' or the first core 105' which is rotatable about its own rotation axis 50', rotation axis 150' to form a first reel, and at the same time moving the first core 5' or the first core 105' by means of the second winding roller 21, the first pressure roller 31 and the second pressure roller 41 until the partially wound first core 5' or the first core 105' reaches a position downstream of the winding channel 7, thus allowing the first movable arm 32 to enter the winding channel 7,

[0053] - cutting the paper web 6 to complete the first roll,

[0054] - introducing the second core 5″ or 105″ into the passage 7, winding it with the cut web 6 about the respective rotation axis 50″ or 150″ to form a second log, and simultaneously moving the second core 5″ or 105″ by means of the first winding roller 11, the second winding roller 21 and the first pressure roller 31 until the second core 5″ or 105″, still partially wound, reaches a position downstream of the winding passage 7 to allow the first movable arm 32 to enter the passage 7 and come into contact with the third core which has just arrived at the winding passage 7,

[0055] - cutting the web 6 wound around the second core 5 ″ or the second core 105 ″, while the second roll formed is discharged by the action of the second winding roller 21 and the second pressing roller 41,

[0056] - The above steps are continued cyclically to form a third roll, a fourth roll, a fifth roll, and so on.

[0057] Advantageously, each first core 5' or first core 105' and second core 5" or second core 105", whichever is which, is moved between an initial position for winding the paper web 6 and a final position for completing the winding of the corresponding roll to be discharged (moving directly at the beginning and therefore moving through the formed roll paper) by the action of at least three of the rollers 11, rollers 21, rollers 31 and rollers 41, for the reasons already described, that is, this is to limit the risk of paper breaks.

[0058] Specifically, in the initial position, the first winding roller 11, the second winding roller 21 and the first pressure roller 31 simultaneously control the web wound around the first core 5' or the second core 5", the second core 105", while the second winding roller 21 and the two pressure rollers 31, 41 simultaneously control the web wound around the first core 105'.

[0059] With reference to the above drawings, regarding machine 1, Figure 1 The paper roll is shown being formed around a core 5 ′, which is controlled by rollers 11 and 21 and a press 41 .

[0060] Figure 1 It is shown that the pressure rollers 31 and 41 are not symmetrically placed relative to the paper roll, which on the other hand occurs in the same step in an alternative embodiment involving the machine 101 (see Fig.11 ).

[0061] Figure 2 A further step in the formation of the paper roll is shown, when the core 5 ′ is moving away from the winding roller 11 to make room for the lowering of the press 31 : during this step, the paper roll is controlled by the roller 21 and the presses 31 and 41 .

[0062] Subsequently, as the web 6 continues to be wound around the first core 5' ( Figure 3 ), the paper roll being formed is again controlled by rollers 21, 31 and 41, away from the first winding roller 11 to leave enough space for the press 31 to be lowered, which slides on the contour of the paper roll to reach the position where winding begins.

[0063] When the first roll is formed (the first roll will be discharged from the winding area), the new core 5" is inserted into the channel 7 and the web 6 is cut at the same time. At this time, the old paper roll wound around the core 5' is completed and the paper web 6 starts to be wound around the second core 5" ( Figure 4The discharge of the log wound around the first core 5 ′ is controlled by the second winding roller 21 and the second pressing roller 41 , while the first pressing roller 31 has now reached the initial position of the channel 7 .

[0064] The core 5" reaches the center line of the rollers 11 and 21, enters the channel 7, and begins to form a new paper roll around the second core 5". At the same time, the press 31 reaches the starting winding position again, and the web formed around the first core 5' leaves the winding step ( Figure 5 ).

[0065] Figure 6 The beginning of the step of winding the web 6 onto the second core 5" is shown at the initial position of the channel 7. The winding is controlled by rollers 11, 21, 31. At the same time, the paper roll associated with the first core 5' is discharged.

[0066] exist Figure 7 In this first enlargement step, the winding around the core 5 ″ begins, which is controlled by the rollers 11 , 21 and 31 ; in this first enlargement step, the press 41 begins to be lowered.

[0067] The increasing roll around the core 5" is still controlled by the two winding rollers 11 and 21 and the pressing roller 31. On the other hand, the press 41 is about to reach the exchange position with the press 31 ( Figure 8 ).

[0068] When the geometry of the pressure roller 31 is not suitable, the pressure roller 41 will take over the pressure roller 31 and start working: from this moment on, the paper roll will be controlled by the two winding rollers 11 and 21 and by the pressure roller 41 ( Fig. 9 ).

[0069] at last, Fig.10 It shows how the winding around the core 5" is controlled by rollers 11, 21 and 41, as shown in FIG. Figure 1 As shown: From this point on, the cycle starts again, as Figure 2 Shown (and described).

[0070] For a variation of machine 101, Fig.11 The process of forming a paper roll around a core 105' by a winding roller 21 and controlled by pressing rollers 31 and 41 is shown.

[0071] like Fig.11 As shown, the axes S3, S4, and S2 connecting the rotation center C5 of the core 105' with the rotation centers C3, C4, and C2 of the corresponding rollers 31, 41, and 21 define two angles, namely, an angle A between the axes S3 and S2 and an angle B between the axes S4 and S2 ( Fig.11 and Fig.11A ).

[0072] According to this configuration, angles A and B are substantially equal, while pressure rollers 31 and 41 remain symmetrical relative to the center of motion of core 105 ′ or 105 ″: the symmetry of the pressures applied by rollers 31 and 41 improves the stability of the system.

[0073] Fig.12 The step of forming the end is shown, wherein the paper roll is always controlled by rollers 21, 31 and 41 and is always under symmetrical pressure relative to the rotation center C5.

[0074] exist Fig.13 In the embodiment of the present invention, the paper roll is still formed around the first core 105', while the paper roll is moving towards the final position of the channel 7, leaving space for the lowering of the press 31. During this step, the paper roll is still controlled by the roller 21 and by the presses 31 and 41.

[0075] Fig.14 The paper roll of the core 105' is shown in the final position at the end of its formation. At the same time, a new core 105" is inserted into the channel 8 of introduction.

[0076] At the time when the core 105 ″ reaches the channel 7 in the initial step, that is to say in a processing step which is practically close to the initial position defined above, the press 31 slides towards the beginning of the channel 7 .

[0077] At the same time, the paper web 6 is cut: at this point, the old paper roll relative to the first core 105' is completed, the web 6 is rewound on the second core 105" just introduced, and the formation of a new roll begins. When the press 31 reaches the winding start position, the discharge of the completed first roll is controlled by the roller 21 and by the press 41.

[0078] Subsequently, the second core 105' arrives at the initial position of the passage 7 between the rollers 11 and 21, and a new paper roll is formed. At the same time, the first pressing roller 31 has reached the winding start position, and the first roll formed on the first core 105' begins the discharge step ( Fig.15 ).

[0079] At this point, the second reel continues its formation, winding the web on the core 105″, rotating around the axis 150″, controlled by the rollers 11, 21 and 31. On the other side of the winding channel 7, the now completed first reel is discharged ( Fig.16 ).

[0080] Fig.17 The enlargement of the paper roll around the second core 105 ″ is shown, which enlargement is always controlled by the two winding rollers 11 and 21 together with the press 31 . The press 41 starts to descend towards the initial position of the channel 7 .

[0081] See also Fig.18The paper roll forming process of the core 105" is still controlled by the rollers 11, 21 and 31, and the roller 41 is about to reach the initial position of the winding channel 7, at which the roller 41 starts to control the winding together with the press 31 and the second winding roller 21, so that the first roller 11 is in a free state ( Fig.19 ). Therefore, when this happens, the core 105" moves to the second winding position and is no longer in contact with the winding roller 11.

[0082] Fig. 20 The step of winding the log around a core 105 ″ is shown, this step continuing to be controlled by the roller 21 and by the two presses 31 and 41 .

[0083] In this case as well, the shapes of the presses 31 and 41 are symmetrical with respect to the rotation center C5 of the core 105″, and the same is applicable to Fig.11 considerations already made in the description.

[0084] at last, Fig.21 The second roll is shown, which is now nearly complete and is about to end its winding around the second core 105", which is still controlled by rollers 21, 31 and 41, and then begins the step of exchanging between the pressure roller 31 and the winding roller 11 (see Fig.14 ).

[0085] From the above description it can be seen how the invention achieves the intended purposes and objects, in particular by creating a machine for producing web material and a related winding method which ensures that the pressure rollers have a firm grip so that the winding of the web can be accomplished without the risk of the web breaking.

[0086] In particular, the rotation of the axis of rotation of the paper winding core is controlled by three rollers during the entire initial winding step, wherein the first press controls the growth of the web without friction problems (self-shielding, towards the inside of the winding channel), ensuring the stability of the machine and the system required to limit to a minimum, or even completely eliminate, vibrations that could endanger the continuity of the paper web to be wound.

[0087] Another advantage of the invention is that, thanks to the action of the press, the control of the winding is no longer governed by the profile of the secondary roller, and therefore it is no longer necessary to personalize the machine, for example by changing the carriage, acting on the speed of rotation of the second winding roller and its opening relative to the first roller, according to the diameter of the core to be wound and the final diameter of the log to be formed. It is thus easier to control the winding of the paper roll.

[0088] Finally, the use of devices that are easily available on the market and the use of common materials make the device economically competitive.

[0089] The invention can be modified and adapted in various ways without departing from the scope of the inventive concept.

[0090] Moreover, all the details of the invention may be replaced by other technically equivalent elements.

[0091] In practice, the materials used, as well as the dimensions, can be of any type as required, provided that they are suitable for the purpose for which they are manufactured.

Claims

1. A machine (1, 101) for producing web material, comprising: At least a first winding roller (11) and a second winding roller (21), wherein the first winding roller (11) and the second winding roller (21) are mounted so as to be rotatable about a first rotation axis (10) and a second rotation axis (20), respectively; at least a first press roller (31) and a second press roller (41), the first press roller (31) and the second press roller (41) being designed to rotate respectively about a third rotation axis (30) located on the first movable arm (32) and a fourth rotation axis (40) located on the second movable arm (42), and defining together with the first winding roller (11) and the second winding roller (21) a winding channel (7) for forming a paper web (6) around a core (5', 5", 105', 105"), wherein the core (5', 5", 105', 105") rotates about its own rotation axis (50', 50", 150', 150"); The core (5', 5", 105', 105") is designed to move between an initial winding position and a final position of the paper web (6) by the action of one or more of the first winding roller (11), the second winding roller (21), the first pressing roller (31) and the second pressing roller (41); The first winding roller (11) and the second winding roller (21) are positioned on opposite sides of the winding channel (7) relative to the first pressing roller (31) and the second pressing roller (41), respectively upstream and downstream of the winding channel (7) relative to the movement of the core (5', 5", 105', 105") during its winding process; The first movable arm (32) and the second movable arm (42) are pivoted about a first secondary rotation axis (30) and a second secondary rotation axis (40), respectively, so that rotation of the first movable arm (32) and the second movable arm (42) causes the first pressing roller (31) and / or the second pressing roller (31) to move toward or away from the first winding roller (11) and / or the second winding roller (21); In the initial position, at least three of the first winding roller (11), the second winding roller (21), the first pressure roller (31) and the second pressure roller (41) are designed to simultaneously control the web of paper wound around the core (5', 5", 105', 105"); the simultaneous contact continues until the paper web (6) wound around the core (5', 5", 105', 105") is cut.

2. The machine (1) according to the preceding claim, wherein: said initial position corresponds to a region of said winding channel (7) in which at least the centre line of said core (5', 5", 105', 105") passes through the axis (K) connecting said centres of rotation (C1, C2) associated with said first winding roller (11) and said second winding roller (21), even more preferably when the outermost periphery of said core (5', 5", 105', 105") is tangent to said axis (K); and The final position corresponds to a region of the winding channel (7) in which the paper web (6) is designed to be cut.

3. The machine (1) according to any one of the preceding claims, wherein: In the initial position, the first winding roller (11), the second winding roller (21) and the first pressing roller (31) are designed to simultaneously control the web wound around the core (5', 5", 105").

4. The machine (1) according to any one of claims 1 to 3, wherein: In the initial position, the second winding roller (21), the first pressing roller (31) and the second pressing roller (41) are designed to simultaneously control the web wound around the core (105').

5. The machine (1) according to any one of the preceding claims, wherein: In the final position, at least the second winding roller (21) and the second pressing roller (41) are designed to simultaneously control the web wound around the core (5', 5", 105', 105").

6. A machine (1) according to the preceding claim, wherein the second winding roller (21) and the second pressing roller (41) are designed to simultaneously control the web of paper in the final position wound around the first core (5', 105'), and at the same time, the first winding roller (11), the second winding roller (21) and the first pressing roller (31) simultaneously control the web of paper in the initial position wound around the second core (5", 105").

7. Machine (1) according to any one of the preceding claims, wherein: The first secondary rotation axis (30) is located in a half plane defined by the axis (K) and opposite the winding channel (7).

8. Machine (1) according to the preceding claim, wherein: The shape of the first movable arm (32) is basically similar to the letter "V", so that the "V" has a vertex angle Z, which is defined by the contact of the symmetry axes (S31, S30) of the ends (32A, 32B) of the arm at the pressure roller (31) and the rotation axis (30), respectively, and the vertex angle Z is 40° to 80°, including 40° and 80°, preferably 45° to 70°, including 45° and 70°, more preferably 50° to 65°, including 50° and 65°, and even more preferably 53° to 60°.

9. A winding method for producing a web material, carried out in a rewinding machine (1, 101) according to any one of the preceding claims, comprising the following steps: - introducing a first core (5', 105') into a winding channel (7) defined by at least a first winding roller (11) and a second winding roller (21) and by at least a first pressing roller (31) and a second pressing roller (41), wherein the first winding roller (11) and the second winding roller (21) are mounted rotatably about a first rotation axis (10) and a second rotation axis (20) of the machine (1, 101), respectively, and the first pressing roller (31) and the second pressing roller (41) are designed to rotate about a third rotation axis (30) located on a first movable arm (32) and a fourth rotation axis (40) located on a second movable arm (42), respectively, so that the first core (5', 105') is controlled simultaneously by the first winding roller (11), the second winding roller (21) and the first pressing roller (31) in an initial position, - winding the paper web (6) from upstream of the winding channel (7) on the first core (5', 105') rotatable around its own rotation axis (50', 150') to form a first roll, and simultaneously moving the first core (5', 105') by means of the second winding roller (21), the first pressure roller (31) and the second pressure roller (41) until the partially wound first core (5', 105') reaches a position downstream of the winding channel (7) to allow the first movable arm (32) to enter the winding channel (7) and cut the paper web (6) wound around the first core (5', 105'), - introducing the second core (5", 105") into the winding channel (7) so that the cut paper web (6) is wound around its own rotation axis (50", 150") to form a second roll, and simultaneously moving the second core (5", 105") by the first winding roller (11), the second winding roller (21) and the first pressure roller (31) until the partially wound second core (5", 105") reaches a position downstream of the winding channel (7) to allow the first movable arm (32) to enter the winding channel (7), cut the paper web (6) wound around the second core (5", 105"), and simultaneously discharge the formed first roll by the action of the second winding roller (21) and the second pressure roller (41), -Continue to perform the above steps cyclically to form a third roll, a fourth roll, a fifth roll, and so on.

10. The method according to the preceding claim, wherein: The web of paper wound around each of the first core and the second core (5', 5", 105', 105") is controlled between an initial winding position of the paper web (6) and a final position when the winding of the corresponding roll is completed by the action of at least three of the first winding roller (11), the second winding roller (21), the first pressure roller (31) and the second pressure roller (41), wherein at the initial winding position, each core has no paper layer wound around the corresponding rotation axis (50', 50", 150', 150").

11. The method according to the preceding claim, wherein: In the initial position, the first winding roller (11), the second winding roller (21) and the first pressing roller (31) simultaneously control the web wound around the first core (5') or the second core (5", 105").

12. The method according to claim 9, wherein: In the initial position, the second winding roller (21), the first pressing roller (31) and the second pressing roller (41) simultaneously control the web wound around the first core (105').

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