Folding or cross-folding unit of a web or sheet of paper in a paper processing machine
By using adjustable separation fingers and vacuum dispensing devices in paper processing machines, the problem of paper adhesion is solved, enabling accurate paper separation and quality maintenance at high speeds, and adapting to the processing of different paper weights.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- MTC MACCINE TRASFORMAZIONE CARTA SRL
- Filing Date
- 2021-11-19
- Publication Date
- 2026-07-21
AI Technical Summary
The folding rollers in existing paper processing machines are prone to paper adhesion at high speeds, resulting in low productivity and poor product quality, and they are unable to handle paper of different weights.
By employing first and second folding rollers, combined with first and second actuation groups, and adjusting the oscillating motion phase of the separating fingers and the position of the vacuum dispensing device, the paper is accurately separated at high speeds, avoiding wrinkles and adhesion.
It enables the maintenance of paper quality at speeds exceeding 300 m/min, adapts to the processing of different paper weights, and improves productivity and product quality.
Smart Images
Figure CN116490450B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of paper processing, and similar products, and more particularly to machines for cross-folding paper webs or sheets.
[0002] The present invention also relates to a method for folding or cross-folding paper webs or sheets according to a determined cross-folding configuration. Background Technology
[0003] As is known in the paper industry, many machines and processes are used to produce tissues, towels, and similar products that are formed as stacks of sheets with cross-folds of a defined height. These products are produced by folding the sheets in a cross-fold manner, meaning that at each fold the final edge of the previous sheet and the starting edge of the next sheet are closed.
[0004] In this way, when using the product, the initial edge of the next sheet is also removed when the sheet is taken out of the stack, thus simplifying the use of the product in some applications.
[0005] A known type of cross-folding machine processes one or more paper webs from one or more reels. These paper webs are cut into sheets of predetermined length at a cutting unit and fed alternately into a folding unit where two counter-rotating folding rollers operate. More precisely, the individual sheets of the web are cut on the cutting rollers, which alternately cooperate with associated counter-rotating blades.
[0006] Among the possible ways to fold the sheet, specifically, an "L" shaped cross fold with two panels, a "Z" shaped cross fold with three panels, and a "W" shaped cross fold with four panels are known.
[0007] In the case of an "L"-shaped cross fold obtained by a "single fold" machine, such as that described in US6228014, the paper web is cut to form two staggered sequences of sheets, which are fed alternately to the folding rollers. In this way, during folding, approximately half of each sheet from the first direction overlaps with a portion of the sheet from the second direction, and vice versa.
[0008] In the case of “Z”-shaped, “W”-shaped, cross-folded, or even more folded panels obtained by a “multi-folding” machine of the known type, such as that described in US3490762, only one paper web is processed, and for the folding rollers, the sequence of sheets comes from only one direction, which has already partially overlapped with each other. As described in EP1520822, the overlap between two subsequent sheets is immediately after cutting by a conveyor roller and a delay roller, which together create a small crease in the previous sheet, with the subsequent sheet partially located below the previous sheet.
[0009] In both single-folding and multi-folding machines, the folding rollers have a circumference that is multiple times the length of the sheet. Specifically, to enable the sheet to be folded or cross-folded, the folding rollers are equipped with holding devices, such as suction holes or mechanical clamps, which are synchronously actuated to alternately initiate and complete each fold between two subsequent panels.
[0010] For example, as described in EP1457444B1, a cross-folding unit typically includes a first folding roller that holds a paper web or sheet at a defined angular distance via a defined suction system (including a defined number of suction holes in longitudinal rows) and then “transfers” the sheet to a second folding roller, which is also provided with a vacuum distribution device symmetrical to the vacuum distribution device of the first suction roller and maintains another predetermined angular distance. This controlled “transfer” of the paper sheet or web from one folding roller to another allows for the desired folding or cross-folding configuration for cross-folding or stacking of folded sheets. The cross-folding unit typically also provides first and second plurality of “separation” fingers that move in phase relative to the respective folding rollers to separate the sheet from the respective outer surface. Separation members are also provided to separate the finished stack of cross-folded sheets from subsequent stacks to be formed. The separation fingers and separator members typically move within corresponding grooves formed on the periphery of the folding rollers.
[0011] However, the folding unit described in EP1457444B1 and other similar folding rollers have some defects.
[0012] Specifically, the forward movement of the processed paper web or sheet along a machine equipped with the suction rollers described in EP1457444 and similar suction rollers shall not exceed a predetermined forward speed threshold, typically about 150 ÷ 200 m / min, which is imposed by structural and functional limitations of certain components of the machine.
[0013] The aforementioned speed of the paper along the machine's forward movement, along with the path to be followed, is used to design the separating fingers, particularly the oscillating motion of the separating fingers, and the suction rollers, especially to position the sealing member at a predetermined angular position. Conversely, if the aforementioned speed values used to design the suction rollers are not considered, various kinds of defects may occur during machine operation.
[0014] Specifically, if the aforementioned threshold is exceeded, due to the inertia of the paper, the processed web or sheet will remain adhered to the surface of the suction roller after the second corner position, i.e., adhered to a portion of the surface located downstream of the second sealing member. This causes the paper web or sheet to advance inaccurately through different parts of the machine and further inevitably damages the quality of the final product, particularly by forming unwanted creases, and may also cause paper blockage, which necessitates stopping the machine to remove the blocked paper, thus resulting in lost time and productivity.
[0015] Therefore, in order to avoid the aforementioned defects, it must operate at low speeds, which reduces the machine's productivity.
[0016] Similar drawbacks exist in existing machines when the paper webs or sheets to be processed have a weight different from the predefined paper weight, and the folding rollers are designed accordingly. In fact, because heavier paper has greater inertia than lighter paper, if the paper webs or sheets being processed have a weight greater than the predefined paper weight, they will remain adhered to the folding rollers beyond the predetermined release point, leading to the aforementioned disadvantages. Typically, due to greater inertia, heavier paper webs or sheets also cover a longer path after the roller's suction ends, resulting in the aforementioned functional problems and a loss of final product quality. Therefore, in addition to low productivity, existing machines equipped with folding rollers are inflexible because they cannot process paper webs or sheets with different weights.
[0017] Examples of folding rollers with the aforementioned disadvantages are described in WO2010 / 140046, WO2019 / 149905 and WO2018 / 019679. Summary of the Invention
[0018] Therefore, the object of the present invention is to provide a cross-folding unit that overcomes the aforementioned disadvantages of the prior art folding rollers, specifically, a type provided with suction holes.
[0019] Specifically, the object of the present invention is to provide a cross-folding unit that can avoid wrinkles or "creases" on the processed sheet, so as to ensure a final product with excellent quality even when the paper web or sheet is traveling at a high speed along the machine, specifically above 300 m / min.
[0020] Another object of the present invention is to provide a method for folding or cross-folding paper webs or sheets in a paper processing machine, which has the aforementioned advantages over prior art methods.
[0021] These and other objectives are achieved by cross-folding units on paper webs or sheets, which include:
[0022] - A first or second folding roller of a paper web or sheet, configured to fold or cross-fold the paper web or sheet in a folding region (35) arranged between the first and second folding rollers according to a predetermined folding or cross-folding configuration.
[0023] - A first plurality of separating fingers and a second plurality of separating fingers, configured to separate the paper web or sheet from the outer surface of the respective folding roller;
[0024] - A first actuation group and a second actuation group are respectively configured to cause the first plurality of separation fingers and the second plurality of separation fingers to oscillate back and forth toward / away from the folding area, thereby causing the corresponding paper web or sheet to separate from the first folding roller and the second folding roller respectively.
[0025] Its main feature is that the first actuation group and the second actuation group are further configured to delay or advance the oscillating motion of the first plurality of separation fingers and the second plurality of separation fingers relative to a predetermined reference oscillating motion, thereby delaying or advancing the moment (tr) when the first plurality of separation fingers and the second plurality of separation fingers are arranged such that the paper web or sheet separates from the first folding roller and the second folding roller, respectively.
[0026] According to another aspect of the invention, a method for folding or cross-folding paper webs or sheets in a paper processing machine includes the following steps:
[0027] - Feed at least one web or sheet of paper in a predetermined forward direction;
[0028] - Fold or cross-fold the paper web or sheet at a predetermined folding area in a paper processing machine, the folding or cross-folding step being performed by a first folding roller and a second folding roller, the folding area being defined between the first folding roller and the second folding roller.
[0029] - The paper web or sheet is separated from the outer surface of the corresponding folding roller by a first plurality of separation fingers and a second plurality of separation fingers, and the separation step causes the first plurality of separation fingers and the second plurality of separation fingers to oscillate back and forth toward / away from the folding area;
[0030] Its main feature is that it also provides an adjustment step to adjust the phase between the first plurality of separating fingers and the second plurality of separating fingers and the first folding roller and the second folding roller respectively, the adjustment step being arranged to delay or advance the oscillating motion of the first plurality of separating fingers and the second plurality of separating fingers.
[0031] Specifically, this adjustment step involves delaying or advancing the oscillations of the first and second separation fingers relative to a predetermined reference oscillation motion. More specifically, the aforementioned reference oscillation motion is arranged to cause the paper web or sheet to separate from the corresponding folding roller at a predetermined reference moment tr*. Attached Figure Description
[0032] The invention will now be illustrated with reference to the accompanying drawings, through the following description of exemplary, rather than limiting, embodiments thereof, in which:
[0033] - Figure 1 A schematic side front view of a first embodiment of the cross-folding unit according to the present invention is shown;
[0034] - Figure 2 and Figure 3 Briefly shown Figure 1 Side front view of possible alternative embodiments of the cross-folding unit;
[0035] - Figure 4 A schematic side front view of a first embodiment of the folding roller according to the invention is shown;
[0036] - Figure 5 and Figure 6 A schematic cross-sectional view of a first embodiment of the folding roller according to the invention is shown, at the moments of capture and release of the paper web or sheet, respectively.
[0037] - Figure 7 and Figure 8 A side front view and a cross-sectional view of the first functional mode of the folding roller according to the present invention are shown in a schematic manner.
[0038] - Figure 9 It shows Figure 8 A magnified view of a portion to schematically illustrate some aspects of the first functional mode of the folding roller according to the invention;
[0039] - Figure 10 and Figure 11 A side front view and a cross-sectional view of the second functional mode of the folding roller according to the present invention are shown schematically, respectively;
[0040] - Figure 12 It shows Figure 11 A magnified view of a portion to schematically illustrate some aspects of the second functional mode of the folding roller according to the invention;
[0041] - Figure 13 A simplified illustration of the invention is shown for use with Figure 4 A longitudinal section view of an alternative embodiment of the folding roller;
[0042] - Figure 14 Briefly shown Figure 13 A side front view of an alternative embodiment of the folding roller;
[0043] - Figure 15 and Figure 16 Shown in side front view and cross-sectional view respectively Figure 13 and Figure 14 The first operating mode of the folding roller;
[0044] - Figure 17 and Figure 18 Shown in side front view and cross-sectional view respectively Figure 13 and Figure 14 The second functional mode of the folding roller;
[0045] - Figure 19 and Figure 21 The invention is shown Figure 13 and Figure 14 Cross-sectional views of other possible alternative embodiments of the roller;
[0046] - Figure 20 It shows Figure 19 A magnified view of a portion to highlight certain technical features;
[0047] - Figure 22 An illustration of the invention for use Figure 4 A side front view of another alternative embodiment of the folding roller;
[0048] - Figure 23 A schematic side front view of a possible embodiment of a paper processing machine using the cross-folding unit according to the invention is shown. Detailed Implementation
[0049] like Figure 1As shown schematically, the cross-folding unit 150 according to the invention includes a first folding roller 1a and a second folding roller 1b. Specifically, the first folding roller 1a and the second folding roller 1b are configured to fold or cross-fold a paper web or sheet at a folding region 35 defined between the two folding rollers according to a predetermined folding or cross-folding configuration.
[0050] In addition to the first folding roller 1a and the second folding roller 1b, the cross-folding unit 150 also includes a first plurality of separation fingers 40a and a second plurality of separation fingers 40b, which are arranged to operate in phase with the first folding roller 1a and the second folding roller 1b, respectively, so that the corresponding paper web or sheet 5 is separated from the outer surface 11 of the corresponding tubular bodies 10a and 10b of the first folding roller 1a and the second folding roller 1b, thereby forming a stack 250 of folded or cross-folded sheets.
[0051] Specifically, a first actuation group 80a and a second actuation group 80b may be provided, which are respectively configured to cause the first plurality of separation fingers 40a and the second plurality of separation fingers 40b to oscillate back and forth toward / away from the aforementioned folding region 35. Specifically, the first actuation group 80a and the second actuation group 80b are also configured to delay or advance the oscillation motion of the first plurality of separation fingers 40a and the second plurality of separation fingers 40b relative to a predetermined reference oscillation motion, thereby delaying or advancing the moment tr at which the first plurality of separation fingers 40a and the second plurality of separation fingers 40b are arranged to cause the paper web or sheet 5 to separate from the corresponding folding rollers 1a and 1b, specifically, delaying or advancing relative to a predetermined reference realization moment tr*.
[0052] Specifically, in Figure 1 In the first embodiment, which is schematically shown, the first actuation group 80a and the second actuation group 80b may respectively include a first actuation device 91a and a second actuation device 91b. More specifically, the first actuation device 91a and the second actuation device 91b are respectively provided with a first motor group 85a and a second motor group 85b. These two motor groups are operatively connected to the first motor shaft 86a and the second motor shaft 86b, respectively. More precisely, the first motor group 85a and the second motor group 85b are arranged to cause the first motor shaft 86a and the second motor shaft 86b to rotate about their respective rotation axes 185a and 185b.
[0053] Specifically, the first actuation group 80a and the second actuation group 80b may respectively include a first oscillator device 90a and a second oscillator device 90b, which are configured to convert rotational motion or power output on the inlet axis into oscillating motion or power output on the outlet axis.
[0054] Mechanical oscillator devices can be of a type known to those skilled in the art, and will not be described in detail here.
[0055] Preferably, the first oscillator device 90a and the second oscillator device 90b (e.g., the first mechanical oscillator and the second mechanical oscillator) may respectively include a first mechanical cam and a second mechanical cam, and preferably include a first linked track cam and a second linked track cam, which are not shown in the figure for simplicity.
[0056] Specifically, the first motor shaft 86a and the second motor shaft 86b can be connected at the inlet to the first oscillator device 90a and the second oscillator device 90b. Advantageously, they each include outlet shafts 83a and 83b, which are connected to the first transmission group 81a and the second transmission group 81b, which are arranged to transmit oscillating motion to the first plurality of separating fingers 40a and the second plurality of separating fingers 40b. Specifically, the aforementioned outlet shafts 83a and 83b are connected to the first transmission group 81a and the second transmission group 81b by corresponding mechanical cams 84a and 84b, which are advantageously linked track cams, not shown in the figures for clarity.
[0057] In this way, the phase between the first plurality of separating fingers 40a and the second plurality of separating fingers and 40b and the other parts of the machine 100 can be obtained, particularly the phase relative to the first folding roller 1a and the second folding roller 1b, so that the first motor group 85a and the second motor group 85b rotate at a determined speed.
[0058] Specifically, compared to existing solutions (especially WO2010 / 140046) that provide crank and connecting rod mechanisms to convert rotary motion into oscillating motion, the solution provided by this invention guarantees higher accuracy. Specifically, the solution provided by this invention allows for very precise adjustment of the phase between the separating fingers 40a and 40b and the corresponding rollers 1a and 1b, particularly by advancing or delaying the oscillating motion of the first plurality of separating fingers 40a and the second plurality of separating fingers 40b relative to a predetermined reference oscillating motion.
[0059] Advantageously, the phase of the separating fingers 40a and 40b can be adjusted, i.e., the oscillating motion can be delayed or advanced relative to other mechanical mechanisms of the machine 100, causing the first motor group 85a and the second motor group 85b to slow down or accelerate within a necessary time period. In other words, starting from a predetermined reference condition in which the first motor group 85a and the second motor group 85b rotate at a reference speed vm*, the first motor group 85a and the second motor group 85b slow down or accelerate for a time interval Δt*, and then their speed returns to the reference speed vm*. Specifically, the rotational speed of the first motor shaft 86a and the second motor shaft 86b can be increased or decreased relative to the set reference speed vm* within a defined time period, thereby advancing or delaying the oscillating motion of the first plurality of separating fingers 40a and the second plurality of separating fingers 40b, respectively, particularly relative to a reference oscillating motion. Specifically, the oscillating motion of the separating fingers 40a and 40b can be accelerated or decelerated in the manner described above.
[0060] Also in Figure 2 In an alternative embodiment schematically shown, the first actuation group 80a and the second actuation group 80b respectively include a first motor group 85a and a second motor group 85b, which are arranged such that the first motor shaft 86a and the second motor shaft 86b rotate about their respective rotation axes 185a and 185b. Furthermore, in this case, a first oscillator device 90a and a second oscillator device 90b of preferred mechanical type are provided, which are arranged to convert the rotational motion of the motor shafts 86a and 86b into oscillating motion, and a first transmission group 81a and a second transmission group 81b are provided, which are arranged to transmit the oscillating motion at the outlets of the first oscillator device 90a and the second oscillator device 90b to the first plurality of separating fingers 40a and the second plurality of separating fingers 40b, respectively.
[0061] However, in this case, it differs from the above references. Figure 1 The first oscillator device 90a and the second oscillator device 90b are advantageously associated with a first adjustment device 94a and a second adjustment device 94b, respectively. These two adjustment devices are configured to adjust the phase of the first plurality of separating fingers 40a and the second plurality of separating fingers 40b relative to the corresponding folding rollers 1a and 1b. Specifically, the first adjustment device 94a and the second adjustment device 94b are arranged to advance or delay the moment tr at which the first plurality of separating fingers 40a and the second plurality of separating fingers 40b are arranged to strike the paper web or sheet 5 to separate it from the corresponding folding rollers 1a and 1b.
[0062] Advantageously, the first adjusting device 94a and the second adjusting device 94b may respectively include a first phase shifter gearbox 95a and a second phase shifter gearbox 95b of a type known to those skilled in the art. More specifically, in this case, the first phase shifter gearbox 95a and the second phase shifter gearbox 95b may be operably connected, for example, to the first motor assembly 85a and the second motor assembly 85b by first drive belts 87a and 87b respectively, and operably connected to the first actuation device 91a and the second actuation device 91b by second drive belts 88a and 88b respectively. More specifically, the first actuation device 91a and the second actuation device 91b are arranged to transmit the generated rotational motion of the first motor assembly 85a and the second motor assembly 85b to the aforementioned first oscillator device 90a and the second oscillator device 90b respectively, which convert the rotational motion into the aforementioned oscillating motion, which is transmitted to the first plurality of separate fingers 40a and the second plurality of separate fingers 40b. The first phase shifter gearbox 95a and the second phase shifter gearbox 95b are respectively equipped with a first electric motor 96a and a second electric motor 96b. These are arranged to adjust the rotational speed of the first actuation device 91a and the second actuation device 91b, thereby adjusting the rotational speed and direction of the first epicycloid gear and the second epicycloid gear (not shown for simplicity) respectively housed in the first phase shifter gearbox 95a and the second phase shifter gearbox 95b.
[0063] In one embodiment of the invention (not shown in the figures for clarity), in any of the above embodiments, the first oscillator device 90a and the second oscillator device 90b are connectable to the respective first ends 81'a and 81'b of the aforementioned first transmission group 81a and second transmission group 81b. The first transmission group and the second transmission group are operatively connected to the first plurality of separate fingers 40a and the second plurality of separate fingers 40b at their second ends 81"a and 81"b opposite to the first ends, respectively. Therefore, the first oscillator device 90a and the second oscillator device 90b are laterally positioned relative to the first plurality of separate fingers 40a and the second plurality of separate fingers 40b, respectively.
[0064] According to one possible operating mode of the invention, the first electric motor 96a and the second electric motor 96b can generally remain stationary under normal conditions, so that the phase of the separating fingers 40a and 40b relative to the rest of the machine 100, particularly relative to the folding rollers 1a and 1b, does not change. When it is necessary to change the phase of the first plurality of separating fingers 40a and the second plurality of separating fingers 40b, the first electric motor 96a and the second electric motor 96b are used to actuate the first and second epicycloid gears respectively, thereby temporarily accelerating or decelerating the second drive belts 88a and 88b. In this way, a delay or advance can be introduced into the oscillating motion of the first plurality of separating fingers 40a and the second plurality of separating fingers 40b, thus delaying or advancing the moment when the paper web or sheet separates from the corresponding folding rollers 1a and 1b, i.e., the moment tr when the first plurality of separating fingers 40a and the second plurality of separating fingers 40b are arranged such that the paper web or sheet 5 separates from the corresponding folding rollers 1a and 1b, particularly, is delayed or advanced relative to a reference separation moment tr*.
[0065] Specifically, refer to the above. Figure 1 and Figure 2 The first folding roller 1a and the second folding roller 1b of the described cross-folding unit 150 may be provided with mechanical (e.g., a known type of mechanical clamp) or pneumatic components for holding the processed paper web or sheet 5. In the latter case, the holding components may be provided with a known type of bell-shaped vacuum dispensing device, or include a sealed section portion of, for example, the type described in EP1457444B1.
[0066] like Figure 3 As shown in the schematic diagram, in addition to the first actuation group 80a and the second actuation group 80b of the aforementioned separating fingers 40a and 40b, the cross-folding unit 150 may also provide a first folding roller 1a and a second folding roller 1b as described below.
[0067] Specifically, each folding roller 1a or 1b of the paper web or sheet 5 fed along the forward direction 15 in a paper processing machine or similar product includes a tubular body 10 configured to rotate about a longitudinal axis of rotation 101 in a predetermined direction of rotation 110 (e.g., clockwise). More precisely, the tubular body 10 of the roller 1a or 1b is provided with an outer surface 11 and an inner surface 12, which are in communication with each other through a plurality of suction holes 3.
[0068] Specifically, the suction holes 3 of the folding rollers 1a or 1b can be organized according to a predetermined number of suction groups (e.g., 2, 3, or 4 suction groups 30), which are positioned at predetermined angular locations on the folding rollers 1a or 1b (e.g., each at 180°, 120°, or 90°). Typically, the angular position of the suction groups 30 depends on the number of sheets that can be placed adjacent to each other on the outer surface 11 of the folding roller 1. The arc between the suction group 30 and the next suction group is equal to the length of the sheet being processed; therefore, depending on the diameter of the folding rollers 1a or 1b, there can be two, three, four, or even more suction groups 30. For example, if there are five suction groups 30 on the folding rollers 1a or 1b, the angular distance between the suction groups 30 will be 72°. In the example below, the folding roller 1 provides three suction groups 30, each suction group comprising two longitudinal rows of suction holes 3 close to each other. The folding roller 1 also provides a suction chamber 20, which is defined within the aforementioned tubular body 10 and pneumatically connected to a device for generating a predetermined vacuum, such as a vacuum pump (not shown in the figures for simplicity, but a type known to those skilled in the art). A vacuum distribution device 50 is also provided, configured to selectively communicate the suction chamber 20 with at least one row of suction holes 3 at predetermined angular positions on the tubular body 10. In this way, as is known, the processed paper sheet or web is drawn in and adheres only to a defined portion of the outer surface 11 of the folding roller 1, which is arranged between a capture point P1 and a release point P2 at defined angular positions, particularly relative to a predetermined reference frame (Xo, Yo, Zo). According to the invention, a shifting device 70 is provided, which is configured to move the aforementioned vacuum distribution device 50 such that the angular position of at least the release point P2 is changed, particularly relative to a predetermined angular position, i.e., a reference release point P2*, which is occupied relative to the aforementioned predetermined reference frame (Xo, Yo, Zo).
[0069] The shifting device 70 can advantageously be operated by an electronic control unit 300, such as a PLC or industrial PC or similar device (see example). Figure 23 The electronic control unit 300 can interact with the operator via a panel interface (e.g., an HMI (Human Machine Interface) type), through which the operator can issue commands and / or adjust the machine 100. For example, the electronic control unit 300 can detect the need to adjust the capture point P1 and / or release point P2, and convey the necessary settings to the operator via the HMI. The operator can then perform the adjustments via the HMI based on the instructions from the electronic control unit 300.
[0070] In this way, the moment ta when the paper web or sheet adheres to the aforementioned outer surface 11 of the folding roller 1a or 1b and / or the moment tr when the paper web or sheet 5 leaves the aforementioned outer surface 11 of the folding roller 1a or 1b can be advanced or delayed.
[0071] Specifically, the aforementioned shifting device 70 may be configured to move the aforementioned vacuum dispensing device 50 according to at least one predetermined operating parameter of the machine 100 in which the folding rollers 1a or 1b are installed. For example, the aforementioned predetermined operating parameter may be the forward speed of the paper web or sheet along the machine 100.
[0072] In this case, specifically, if the forward speed v of the paper web or sheet is greater than a predetermined reference value v*, or if the machine operating speed increases, the shifting device 70 is arranged to move the vacuum dispensing device 50, thereby advancing the time tr at which the paper web or sheet separates from the folding rollers 1a or 1b. Specifically, in this case, the shifting device 70 may be configured such that the aforementioned vacuum dispensing device 50 rotates in the opposite direction to the aforementioned rotation direction 110 of the folding rollers or about the rotation axis 101. Figures 7 to 9 ).
[0073] Conversely, if machine 100 is expected to operate at a paper feed speed lower than the aforementioned reference value v*, or simply if the operating speed of machine 100 is reduced, the shifting device 70 is arranged to move the aforementioned vacuum dispensing device 50, thereby delaying the release of the paper web or sheet relative to the reference condition. More specifically, in this case, the shifting device 70 will be arranged to rotate the aforementioned vacuum dispensing device 50 in the same direction as the aforementioned rotation direction 110 of the folding roller or about the rotation axis 101. Figures 10 to 12 ).
[0074] In a preferred configuration of the invention, the vacuum dispensing device 50 can be rotated according to at least one operating parameter (e.g., the paper feed speed). In this case, the electronic control unit 300 can operate the shifting device 70 to cause a rotational displacement of the vacuum dispensing device 50. The electronic control unit 300 can operate the shifting device 70 according to a predetermined function or an algorithm based on real-time calculation (e.g., a self-learning algorithm or, in general, an artificial intelligence algorithm).
[0075] In an alternative embodiment of the invention, the capture point P1 and / or release point P2 can be controlled so that the angular position of the vacuum distribution device 50 alternates between at least two predetermined angular positions. For example, Figure 12 The first release point P2' can correspond to a slow paper feed speed (e.g., between 50 m / min and 100 m / min), while Figure 9The second release point P2" can correspond to a high forward speed (e.g., above 250 m / min). In this case, a speed threshold can be set, and if this threshold is exceeded, the shifting device 70 can be operated to move the vacuum distribution device 50 from the first release point P2' to the second release point P2" to advance or delay the separation of the paper web or sheet 5. The actuation command for the shifting device 70 can be given directly by the electronic control unit 300 or by the operator via the HMI interface.
[0076] Another operating parameter of machine 100 may be the paper thickness s or paper weight of the processed web or sheet, and the shifting device 70 may be arranged to move the vacuum dispensing device 50 according to this operating parameter. Specifically, if the paper thickness is greater than a predetermined reference thickness s*, the shifting device 70 is arranged to move the vacuum dispensing device 50 such that the time tr at which the paper web or sheet is released from roller 1 is advanced relative to the release reference time tr*.
[0077] Specifically, in this case, the shifting device 70 can be arranged to rotate the vacuum dispensing device 50 in a direction opposite to the rotation direction 110 of the tubular body 10 about the longitudinal axis 101. Conversely, when the paper thickness is less than a predetermined reference thickness s*, the shifting device 70 is arranged to move the vacuum dispensing device 50, thereby delaying the release of the paper web or sheet from the roller 1. Specifically, in this case, the shifting device 70 can be arranged to rotate the vacuum dispensing device 50 in a rotation direction consistent with the rotation direction of the tubular body 10 about the longitudinal axis 101.
[0078] In this configuration, machine 100 can be adjusted according to the product, i.e., according to the characteristics of the paper to be processed. The shifting device 70 can operate differently depending on the type of paper or product being processed, thus providing a significant advantage in machine 100 setup during product changes. Each product or paper type can correspond to a specific movement of the shifting device 70, or to a specific reference value for the paper speed v*, thereby optimizing the position of the capture point P1 and / or release point P2 for each specific product or paper type.
[0079] In a preferred embodiment of the invention, the aforementioned shifting device 70 may be configured to move (in particular rotate) the vacuum dispensing device 50, specifically delaying or advancing the moment tr at which the paper web or sheet is released from the outer surface 11 under the operating conditions of the machine 100 (meaning during the rotation of the tubular body 10 around the aforementioned longitudinal axis of rotation 101). In this way, specifically, the vacuum dispensing device 50 is movable such that it gradually follows the increase or decrease in the forward speed of the paper web or sheet.
[0080] Specifically, in the first embodiment, the aforementioned vacuum distribution device 50 may include a fixed tubular body 25 coaxially mounted within the aforementioned tubular body 10. More specifically, the aforementioned fixed tubular body 25 is pneumatically connected to a device for generating a predetermined vacuum level and is provided with at least one orifice 26. More precisely, the vacuum distribution device 50 may also include a first sealing member 27a and a second sealing member 27b, which are integral with the fixed tubular body 20 on opposite sides of the orifice 26 or each orifice and are longitudinally positioned relative to the tubular body 10. Specifically, the displacement device 70 may be configured to cause rotation of the fixed tubular body 25 about the aforementioned longitudinal rotation axis 101.
[0081] More specifically, such as Figure 13 As schematically shown, the aforementioned displacement device 70 may be arranged to engage and fix the tubular body 25 at least at the actuating portion 75, which is advantageously a portion that protrudes axially from one end of the tubular body 10.
[0082] Specifically, if the purpose is relative to the reference condition tr* ( Figure 9 (The dashed line in the diagram) The early release time tr, for example because machine 100 operates at a paper feed speed higher than the reference speed, especially for higher productivity, or to handle a class of paper with a weight s lighter than the reference paper weight s*, the shifting device 70 can be arranged so that the fixed tubular body 25 rotates in the opposite direction to the predetermined rotation direction 110 of the tubular body 10. In this way, practically, as... Figure 9 As shown in the schematic diagram, the paper sheet or web moves from the release point P2 on the outer surface 11 of the tubular body 10 to upstream of the reference release point P2*.
[0083] Conversely, if the purpose is to operate the machine at a slower speed than the reference speed v*, or to process a class of paper with a weight greater than the reference paper weight s*, the shifting device 70 can be arranged such that the fixed tubular body 25 rotates about the longitudinal axis of rotation 101 in a rotational direction consistent with a predetermined rotational direction 110 of the tubular body 10, thereby delaying the release time tr of the paper web or sheet 5 relative to the reference realization time tr* (see reference v*). Figures 7 to 9 In this way, in fact, as Figure 9 As shown in the schematic diagram, the paper sheet or web moves from the release point P2 on the outer surface 11 of the tubular body 10 to downstream of the reference release point P2*.
[0084] In an alternative embodiment of the invention, the capture point P1 and / or release point P2 vary with the speed of the machine 100, conveniently advancing or delaying at least one of two moments between ta and tr, at which the sheet is held on and released from the outer surface 11 of the folding rollers 1a or 1b, respectively. In this case, to advance or delay the two moments ta or tr, advantageously, no reference is made to a predetermined speed v*, but rather the electronic control unit 300 can be configured to calculate the position of the capture point P1 and / or release point P2 based on the speed of the machine 100, and directly operate the shifting device 70, or indirectly operate the shifting device by an operator giving commands via an HMI device.
[0085] like Figures 13 to 18 To illustrate in general terms, especially as Figure 14 As shown, the shifting device 70 may include an actuation device 73. Specifically, the actuation device 73 may be an actuator, such as a pneumatic actuator, a mechanical actuator, or an electromechanical actuator.
[0086] Preferably, the actuating device 73 can be a motor, particularly an electric motor, which is provided with a motor shaft (not shown) arranged to rotate about a rotation axis 173. The motor shaft can be arranged to engage with a worm 71 that slides along a sliding direction 171. More precisely, the worm 71 is pivotally connected at a engagement portion 76 to an actuating portion 75 integral with the fixed tubular body 25.
[0087] Therefore, in order to cause the fixed tubular body 25 to rotate in the first direction, particularly in the direction opposite to the rotation direction 110 of the tubular body 10, the motor is operated such that the motor shaft rotates about the rotation axis 173 on the first rotation axis 172 (see...). Figure 15 In this way, as described above, release point P2 (at... Figure 13 In the case of capture point P1, it is located at an angle upstream of the reference release point P2*. Therefore, the release time tr is earlier than the reference time tr* (see also...). Figure 9 ).
[0088] Conversely, in order to cause the fixed tubular body 25 to rotate in the second rotational direction, particularly in the direction consistent with the rotational direction 110 of the tubular body 10, the motor is operated such that the motor shaft rotates about the rotation axis 173 in the second rotational direction 172' (see...). Figure 17 In this way, as described above, release point P2 (at... Figure 15 In the case of capture point P1, the angular position is located downstream of the angular position of the reference release point P2*. Therefore, the release time tr is delayed relative to the reference time tr* (see also...). Figure 12 ).
[0089] In an alternative embodiment of the invention, instead of a motor, a linear electric actuator, i.e., an electric motor whose axis can slide without rotating, can be used. In this way, the axis of the electric motor can be directly connected to the actuation portion 75, which is integral with the fixed tubular body 25, at the engagement portion 76.
[0090] Specifically, in the above implementation scheme and specifically in Figures 4 to 18 As shown, the suction chamber 20 is pneumatically connected to the suction port 3 by a vacuum distribution device 50 equipped with a first sealing member 27a and a second sealing member 27b, which are radially oriented and positioned on opposite sides of the port or each port 26. More specifically, there are no other elements between the first sealing member 27a and the second sealing member 27b capable of sealing the suction port 3. Therefore, the suction chamber is defined by the first sealing member 27a and the second sealing member 27b.
[0091] exist Figure 19 and Figure 20 In an alternative embodiment, schematically shown, the aforementioned vacuum dispensing device 50 includes a fixed tubular body 25 coaxially mounted within the tubular body 10 and pneumatically connected to a device for generating a predetermined vacuum level. More specifically, the fixed tubular body 25 is provided with at least one hole 26 having a predetermined angular amplitude, particularly corresponding to the length of the sheet or panel to be processed, or the angular amplitude corresponding to a portion of the path along which the paper web or sheet 5 covers the roller.
[0092] In this configuration, the vacuum distribution device 50 includes a plurality of sealing members 27 integral with and longitudinally positioned to the tubular body 10. More specifically, each sealing member 27 is associated with at least one row of suction holes 3, which are arranged to pneumatically connect the outer surface 11 to a means for generating a predetermined vacuum degree through the holes 26. Furthermore, an annular sealing member 28 may be provided between the sealing members 27 associated with two different suction groups 30 and subsequent sealing members 27. In this configuration, the displacement device 70 is advantageously configured to cause rotation of the fixed tubular body 25 about a longitudinal axis of rotation 101. More precisely, for example, as... Figure 20 As detailed in the diagram, in order to release the paper web or sheet 5 earlier than the reference condition tr*, the fixed tubular body 25 can rotate in the opposite direction to the rotation direction 110 of the tubular body 10. In this way, the release point P2 will be positioned upstream of the angular position of the reference release point P2* in the rotation direction 110, because the suction hole 3 will leave the paper web or sheet 5 earlier than the reference condition (roughly shown in dashed lines in the diagram).
[0093] exist Figure 21 Another alternative embodiment, schematically shown in the reference above, is similar to the one described above. Figure 8 , Figure 11 , Figure 16 and Figure 18 As shown in the embodiment, the first sealing member 27a and the second sealing member 27b are arranged to extend longitudinally into the tubular body 10 between the inner surface 12 and the fixed tubular body 25. However, in this case, at least one sealing member (e.g., the second sealing member 27b) is mounted on a support member 21 that is movable relative to the fixed tubular body 25, for example, within a guide member 22 formed along the outer periphery of the fixed tubular body 25. Therefore, in this case, the displacement device 70 can be configured to move the movable support member 21, particularly to rotate it about the longitudinal axis 101.
[0094] In this way, only the release point P2 can be changed, while the capture point P1 can be in a fixed position and consistent with the reference angular position P1*.
[0095] Alternatively, a first displacement device 70a and a second displacement device 70b may be provided, one of which is configured to move the movable support 21, and the other is configured to move the tubular body 25. Thus, in this way, the capture point P1 and the release point P2 ( Figure 22 They change independently of each other.
[0096] In an alternative embodiment of the invention (not shown), the first sealing member 27a and the second sealing member 27b can be mounted on two supports that are movable independently of each other to adjust the capture point P1 and / or release point P2, thereby keeping the fixed tubular body 25 fixed. In another alternative embodiment of the invention, the displacement device 70 may include a linear actuator, particularly a mechanical, electrical, electromechanical, or pneumatic type linear actuator, arranged such that the vacuum dispensing device 50 rotates against a movable abutment member. In this way, the angular position of the vacuum dispensing device 50 can be adjusted by changing the position of the movable abutment member.
[0097] exist Figure 23 In another embodiment, schematically illustrated, upstream of the cross-folding unit 150 according to the invention, a first cutting roller 1c and a second cutting roller 1d are provided, which are configured to cut corresponding paper webs in predetermined first and second plurality of sheets of predetermined lengths, respectively. According to the invention, the first cutting roller 1c and the second cutting roller 1d may also be provided with corresponding shifting devices 70c and 70d, based on the above-mentioned reference folding rollers. Figures 4 to 18In one of the described embodiments, the two shifting devices are configured to move the corresponding vacuum dispensing device 50 such that the release point P2 of the corresponding treated paper web or sheet is delayed or advanced for different purposes, and in some cases, the capture point P1 of the corresponding treated paper web or sheet is also delayed or advanced.
[0098] The phases of both the first plurality of separating fingers 40a and the second plurality of separating fingers 40b, as well as the phases of the positions of the capture point P1 and / or release point P2 relative to a reference value, can be adjusted and can be calculated relative to the machine 100's startup conditions and / or operating conditions. When the aforementioned reference value is one of the machine's startup conditions or a zero point, the reference point can preferably be calculated based on the paper weight or the sheet size. In addition to changing the paper weight or the paper web or sheet 5, the function used to calculate the instantaneous moments of the capture point P1 and / or release point P2 and / or the release moments tr of the separating fingers 40a and 40b can also be changed.
[0099] When the reference value relates to the machine's state, i.e., the moment when the machine is in operation and therefore operating at an instantaneous speed or a predetermined speed, the release time tr of the capture point P1 and release point P2 and / or the separation fingers 40a and 40b is calculated by the electronic control unit 300 using a defined algorithm. This calculation can be of the threshold speed type, meaning that the capture point P1 and / or release point P2 can be changed when the predetermined operating speed is exceeded upwards or downwards. In an alternative embodiment of the invention, the capture point P1 and / or release point P2 can be changed from a starting value or zero value, thereby calculating them based on a set speed or instantaneous speed. The function relating the instantaneous speed and position of the capture point P1 and release point P2 can be of any type, for example, linear, nonlinear, or other types. Furthermore, these functions can be selected based on paper weight, or paper size that adapts the machine 100 to a specific paper type, or product size. Similar to the above, the delay or advancement of the separation times ta and tr of the fingers 40a and 40b can be changed, thereby automatically adapting the machine 100 to changes in operating conditions and / or product type.
[0100] Although for the sake of clarity Figure 1 , Figure 2 and Figure 3 Not shown, but it should be noted that the type of separation member known to those skilled in the art can be provided and configured to separate the finished stack 250 of folded or cross-folded sheets from the subsequently formed stack 250.
[0101] The foregoing description of exemplary embodiments of the invention has so fully disclosed the invention from a conceptual standpoint that others will be able to modify and / or adapt these embodiments for various applications by applying present knowledge without further study and without departing from the invention, and therefore it should be understood that such modifications and alterations must be considered equivalent to the specific embodiments. Devices and materials used to achieve the different functions described herein may have different properties without departing from the scope of the invention. It should be understood that the wording or terminology used herein is for descriptive purposes and not for limitation.
Claims
1. A cross-folding unit for paper webs or sheets, the cross-folding unit comprising: - A first folding roller (1a) and a second folding roller (1b) of a paper web or sheet, wherein the first folding roller and the second folding roller are configured to fold or cross-fold the paper web or sheet in a folding area (35) arranged between the first folding roller (1a) and the second folding roller (1b) according to a predetermined folding configuration. - A first plurality of separating fingers (40a) and a second plurality of separating fingers (40b), the first plurality of separating fingers and the second plurality of separating fingers being configured to separate the paper web or sheet from the outer surface (11) of the respective folding roller; - A first actuation group (80a) and a second actuation group (80b), the first actuation group and the second actuation group being respectively configured to cause the first plurality of separating fingers (40a) and the second plurality of separating fingers (40b) to oscillate back and forth toward / away from the folding area (35), thereby causing the corresponding paper web or sheet to separate from the first folding roller and the second folding roller respectively. The cross-folding unit is characterized in that the first actuation group (80a) and the second actuation group (80b) are also configured to delay or advance the folding motion relative to a predetermined reference oscillation motion, respectively. The oscillating motion of the first plurality of separating fingers (40a) and the second plurality of separating fingers (40b) thereby delaying or advancing the moment (tr) at which the first plurality of separating fingers (40a) and the second plurality of separating fingers (40b) are arranged to cause the paper web or sheet to separate from the first folding roller (1a) and the second folding roller (1b) respectively, and wherein the first actuation group (80a) and the second actuation group (80b) are operated by an electronic control unit (300) according to the instantaneous operating speed of the first folding roller (1a) and the second folding roller (1b).
2. The cross-folding unit for paper webs or sheets according to claim 1, wherein the first folding roller (1a) and the second folding roller (1b) each comprise: - A tubular body (10) configured to rotate about a longitudinal axis of rotation (101) in a predetermined direction of rotation (110), the tubular body (10) having an outer surface (11) and an inner surface (12), the outer surface and the inner surface being pneumatically connected to each other through a plurality of suction holes (3) according to a plurality of longitudinal rows; - Suction chamber (20), which is confined within the folding roller (1) and pneumatically connected to a vacuum generating device configured to generate a predetermined vacuum degree; - A vacuum dispensing device (50) is configured such that the suction chamber (20) is selectively pneumatically connected to at least one row of suction holes (3) at a defined angular position on the tubular body (10), thereby causing the treated paper sheet or web to be suctioned (100) and adhered to the corresponding portion of the outer surface (11) of the folding roller (1) between a capture point (P1) and a release point (P2) at a defined angular position.
3. The cross-folding unit for paper webs or sheets according to claim 2, further comprising a shifting device (70) configured to move the vacuum dispensing device (50) such that the angular position of the capture point (P1) and / or the release point (P2) of the paper web or sheet is changed, and thus the moment when the paper web or sheet adheres to or leaves the outer surface (11) of the first folding roller (1a) or the second folding roller (1b) is advanced or delayed.
4. The cross-folding unit for paper webs or sheets according to claim 3, wherein the shifting device (70) is configured to move the vacuum dispensing device (50) during the rotation of the tubular body (10) about the longitudinal axis of rotation (101).
5. The cross-folding unit for paper webs or sheets according to claim 3, wherein the vacuum dispensing device (50) comprises a fixed tubular body (25) coaxially mounted within the tubular body (10), the fixed tubular body (25) being pneumatically connected to a device for generating a predetermined vacuum degree and having at least one hole (26), and wherein the shifting device (70) is configured to cause the fixed tubular body (25) to rotate about the longitudinal axis of rotation (101).
6. The cross-folding unit for paper webs or sheets according to claim 3, wherein the shifting device (70) comprises an actuating device (73) selected from the group consisting of: - Linear actuator; -Mechanical actuator; - Electric actuator; - Electromechanical actuator; - Pneumatic actuator; Or a combination thereof.
7. The cross-folding unit for paper webs or sheets according to claim 5, wherein the vacuum dispensing device (50) includes a first sealing member (27a) and a second sealing member (27b) integral with the fixed tubular body (25) on opposite sides of the hole (26), the first sealing member (27a) and the second sealing member (27b) being longitudinally positioned relative to the tubular body (10).
8. The cross-folding unit for paper webs or sheets according to claim 2, wherein the vacuum dispensing device (50) comprises a plurality of sealing members integral with the tubular body (10) and longitudinally positioned relative to the tubular body, each of the plurality of sealing members being associated with at least one row of suction holes (3) arranged to pneumatically connect the outer surface (11) to a means for generating a predetermined vacuum degree.
9. The cross-folding unit according to any one of the preceding claims, wherein the first actuation group (80a) and the second actuation group (80b) respectively comprise: - A first motor group (85a) and a second motor group (85b), the first motor group and the second motor group being configured to cause the first motor shaft (86a) and the second motor shaft (86b) to rotate about their respective rotation axes (185a, 185b); - A first oscillator device (90a) and a second oscillator device (90b), the first oscillator device and the second oscillator device being configured to convert the rotational motion of the first motor shaft (86a) and the second motor shaft (86b) on the inlet axis into oscillating motion on the outlet axis, so as to transmit the oscillating motion to the first plurality of separating fingers (40a) and the second plurality of separating fingers (40b).
10. The cross-folding unit according to claim 9, wherein the first motor group (85a) and the second motor group (85b) are further configured to change the rotational speed of the first motor shaft (86a) and the second motor shaft (86b) relative to a reference rotational speed (vm*) within a defined time interval (Δt*), such that the oscillating motion of the first plurality of separating fingers (40a) and the second plurality of separating fingers (40b) is advanced or delayed, respectively.
11. The cross-folding unit according to any one of claims 1 to 8, wherein the first actuation group (80a) and the second actuation group (80b) respectively comprise: - A first motor group (85a) and a second motor group (85b), the first motor group and the second motor group being configured to cause the first motor shaft (86a) and the second motor shaft (86b) to rotate about their respective rotation axes (185a, 185b); - A first oscillator device (90a) and a second oscillator device (90b), the first oscillator device and the second oscillator device being configured to convert the rotational motion of the first motor shaft (86a) and the second motor shaft (86b) into the oscillating motion of the first plurality of separating fingers (40a) and the second plurality of separating fingers (40b); It also provides a first adjustment device (94a) and a second adjustment device (94b), which are respectively associated with the first oscillator device (90a) and the second oscillator device (90b) and configured to advance or delay the moment (tr) at which the first plurality of separation fingers (40a) and the second plurality of separation fingers (40b) are arranged to strike the paper web or sheet (5) so that the paper web or sheet (5) separates from the first folding roller (1a) and the second folding roller (1b) respectively.
12. The cross-folding unit according to claim 11, wherein the first adjusting device (94a) and the second adjusting device (94b) respectively include a first phase shifter gearbox (95a) and a second phase shifter gearbox (95b).
13. The cross-folding unit according to claim 12, wherein the first phase shifter gearbox (95a) and the second phase shifter gearbox (95b) are respectively provided with a first epicycloid gear and a second epicycloid gear, the first phase shifter gearbox (95a) and the second phase shifter gearbox (95b) are respectively operably connected to a first electric motor (96a) and a second electric motor (96b), the first electric motor and the second electric motor are configured to operate the first epicycloid gear and the second epicycloid gear respectively, such that the oscillating motion of the first plurality of separating fingers (40a) and the second plurality of separating fingers (40b) is accelerated or decelerated.
14. The cross-folding unit according to claim 4, wherein the shifting device (70) and / or the first actuation group (80a) and the second actuation group (80b) are configured to be operated by an operator via an interface panel or HMI "human-machine interface".
15. The cross-folding unit according to claim 14, wherein the shifting device (70) is operated by an electronic control unit (300) according to at least one of the following parameters: -Instantaneous operating speed of the first folding roller (1a) and the second folding roller (1b); - The length of the paper sheet; - Paper weight.
16. The cross-folding unit according to claim 2, wherein the plurality of longitudinal rows of suction holes (3) are organized according to a plurality of suction groups (30), each of the plurality of suction groups comprising at least two longitudinal rows of suction holes (3) close to each other.
17. The cross-folding unit according to claim 2, wherein the plurality of longitudinal rows of suction holes (3) are organized according to a plurality of suction groups (30), each of the plurality of suction groups comprising at least 3 longitudinal rows of suction holes (3) close to each other.
18. The cross-folding unit according to claim 16 or 17, wherein the arc arranged between one suction group and the next suction group of the plurality of suction groups is equal to the length of the processed sheet (5).
19. The cross-folding unit according to claim 12, wherein the first phase shifter gearbox (95a) and the second phase shifter gearbox (95b) are operably connected to the first motor group (85a) and the second motor group (85b) respectively by a first drive belt and a second drive belt.
20. The cross-folding unit according to claim 19, wherein the first phase shifter gearbox (95a) and the second phase shifter gearbox (95b) are further operably connected by a second drive belt (88a, 88b) to a first actuation device (91a) and a second actuation device (91b), the first actuation device (91a) and the second actuation device (91b) being arranged to transmit rotational motion caused by the first motor assembly (85a) and the second motor assembly (85b) to the first oscillator device (90a) and the second oscillator device (90b), respectively.
21. The cross-folding unit according to claim 20, wherein the first phase shifter gearbox (95a) and the second phase shifter gearbox (95b) are respectively provided with a first electric motor (96a) and a second electric motor (96b), the first electric motor and the second electric motor being arranged to adjust the rotational speed of the first actuation device (91a) and the second actuation device (91b).
22. The cross-folding unit according to claim 9, wherein the first oscillator device (90a) and the second oscillator device (90b) are respectively provided with a first linked track cam and a second linked track cam.
23. The cross-folding unit of claim 9 further includes a first transmission group (81a) and a second transmission group (81b), wherein the first oscillator device (90a) and the second oscillator device (90b) are connected at respective first ends (81'a, 81'b) of the first transmission group (81a) and the second transmission group (81b), and the first transmission group (81a) and the second transmission group (81b) are operatively connected to the first plurality of separate fingers (40a) and the second plurality of separate fingers (40b) at respective second ends (81”a, 81”b) opposite to the first ends (81'a, 81’b).
24. A method for cross-folding a paper web or sheet in a paper processing machine, the method comprising the following steps: - Feed at least one paper web or sheet (5) in the forward direction (15); - The paper web or sheet (5) is cross-folded at a predetermined folding area of the paper processing machine, the cross-folding step being performed by a first folding roller (1a) and a second folding roller (1b) in a folding area (35) defined between them; - The paper web or sheet is separated from the outer surface (11) of the corresponding folding roller by a first plurality of separation fingers (40a) and a second plurality of separation fingers (40b), and the separation step is performed to cause the first plurality of separation fingers (40a) and the second plurality of separation fingers (40b) to oscillate back and forth toward / away from the folding area (35) by a first actuation group (80a) and a second actuation group (80b); The method is characterized by providing an adjustment step for adjusting the phase between the first plurality of separating fingers (40a) and the second plurality of separating fingers (40b) and the first folding roller (1a) and the second folding roller (1b), respectively. The adjustment step is arranged to delay or advance the oscillating motion of the first plurality of separating fingers (40a) and the second plurality of separating fingers (40b) relative to a predetermined reference oscillating motion, thereby at least delaying or advancing the moment (tr) at which the first plurality of separating fingers (40a) and the second plurality of separating fingers (40b) are arranged such that the paper web or sheet separates from the first folding roller (1a) and the second folding roller (1b), respectively. The first actuation group (80a) and the second actuation group (80b) are operated by an electronic control unit (300) according to the instantaneous operating speed of the first folding roller (1a) and the second folding roller (1b).
25. The method for cross-folding a paper web or sheet according to claim 24, wherein the oscillating motion of the first plurality of separating fingers (40a) and the second plurality of separating fingers (40b) is adjusted by an electronic control unit (300) according to at least one of the following parameters: -Instantaneous operating speed of the folding roller (1); -The predetermined operating speed of the folding roller (1); - The length of the sheet; - Paper weight.
26. The method for cross-folding a paper web or sheet according to claim 25, wherein the electronic control unit (300) automatically adjusts the oscillating motion of the first plurality of separating fingers (40a) and the second plurality of separating fingers (40b), or adjusts the oscillating motion of the first plurality of separating fingers (40a) and the second plurality of separating fingers (40b) based on commands received by an interface panel or HMI, i.e., a human-machine interface.