Suction roller for sheet-shaped products

Abstract

A suction roller (1) for sucking sheet-like products (5) fed in a paper processing machine in an advancing direction, comprising a rotating tubular body (20) rotating about a longitudinal rotation axis (120) and provided with an outer side surface (21) and an inner side surface (22), the outer and inner surfaces are pneumatically connected to each other by a plurality of suction channels (23) arranged in a predetermined number of longitudinal rows (3). Furthermore, the suction chamber (16) is arranged to be pneumatically connected to means (50) for generating an air flow and to suction distribution means (40) which selectively communicate the suction chamber (16) with the suction channels (23) of the at least one longitudinal row (3) at a predetermined angular position of the rotating tubular body (20), in this way, the processed sheet-shaped product (5) is sucked and sucked to a corresponding part of the outer side surface (21) of the rotating tubular body (20). The suction channel (23) has a suction surface area greater than 1 mm2 per millimeter length at the outside surface (21) of the rotating tubular body (20).

Description

Technical Field

[0001] This invention relates to the field of paper processing and similar products, and more particularly, to a suction roller, such as a forward roller, a cutting roller, a folding roller or a staggered folding roller for a machine for staggered folding of paper webs or sheets, the suction roller having suction holes connected to a vacuum system, so that paper sheets or webs are adsorbed onto its surface.

[0002] Furthermore, the present invention relates to a paper converting machine that includes at least such suction rollers. Background Technology

[0003] As is well known, many machines used in the paper industry (such as rewinders, staggered folders, and folding machines) are equipped with systems that adsorb the paper web or sheet being processed onto the surface of the rolls in a defined working step so as to feed the paper web or sheet along a desired path.

[0004] Specifically, this system is used to perform basic operations such as cutting paper, transferring paper very quickly from one roller to another, or performing final folding of the paper to obtain a sheet package with staggered folds according to the desired folding configuration.

[0005] In recent years, suction rollers equipped with pneumatic systems have been widely developed in the field of paper processing machinery, enabling the paper sheets or webs being processed to adhere to a defined portion of the outer surface of the suction roller. More specifically, as described in EP1457444 or EP2514698, such suction systems provide a device for generating a defined vacuum level, which is pneumatically connected to the interior of the suction roller. More specifically, such suction rollers include a rotating tubular body adapted to rotate about a longitudinal axis of rotation and a fixed tubular body coaxial with and located inside the rotating tubular body. The surface of the rotating tubular body is provided with a defined number of paired longitudinal rows of suction holes (typically 3 or 4 rows of paired holes). Additionally, the fixed tubular body is provided with longitudinal rows of orifices. A vacuum distribution device is provided between the rotating tubular body and the fixed tubular body, comprising first and second sealing elements or gaskets arranged longitudinally at two different angular positions relative to the suction roller and positioned on opposite sides relative to the aforementioned rows of orifices of the fixed tubular body. In this way, the inner surface of the rotating tubular body, the outer surface of the fixed tubular body, and the longitudinal sealing element form a suction chamber.

[0006] During the rotation of the rotating tubular body relative to the fixed tubular body, the aforementioned multiple rows of holes are selectively pneumatically connected to the aforementioned device for generating a vacuum from the aforementioned suction dispensing device. More specifically, the holes of the rotating roller, which are positioned between the two sealing elements only at predetermined times, will exert a suction effect on the processed paper sheet or web, causing it to adhere to the corresponding portion of the outer surface of the suction roller.

[0007] In existing folding rolls and / or feed rolls, it is known to use holes on the outer surface of a rotating tubular body to suck up, hold, fold, and drag paper webs or sheets. Suction is achieved by a vacuum pump; therefore, the diameter of the holes is relatively small to avoid losing too much suction capacity. Typically, the suction holes are arranged in a predetermined number of longitudinal rows. The number of suction holes in each longitudinal row is selected according to the desired purpose, as each row corresponds to a precise portion of the sheet to be held. For example, one row of suction holes may be used to hold the beginning or head of the sheet, another row to hold the end or tail, and yet another row to hold the middle portion of the sheet. In some cases, the middle portion of the sheet may be held by two different rows of holes, each row having a different number of holes. Typically, each row may have a different number of holes, and the diameter of the holes themselves in different rows may differ.

[0008] The total number of suction holes in each longitudinal row depends on the dimensions of the processing line, that is, on the length of the rotating tubular body. Each suction hole on the outer surface of the rotating tubular body corresponds to a suction channel that pneumatically connects the outer surface of the rotating tubular body to its inner surface. These channels are typically straight because they are formed by mechanically drilling the rotating tubular body. In other cases (as described in EP3725112), multiple groups or blocks may be configured with multiple sets of suction holes screwed onto the rotating tubular body so that the outer surface of the block coincides with the outer surface of the rotating tubular body. Again, in this case, multiple rows of suction holes are provided, with each longitudinal row adapted to hold a specific portion of the sheet. For example, in EP3725112, each block has a set of holes formed by a maximum of two rows (three per row) of holes aligned with each other, which are substantially equivalent to holes formed by directly drilling into the rotating tubular body as shown in EP3826950. These blocks are mounted aligned with each other along the longitudinal direction of the suction roller to form multiple rows of holes that are completely equivalent to those formed directly on the rotating tubular body. Typically, in the case where holes are obtained by directly penetrating the rotating tubular body or, as described above, where holes are formed on the blocks, the distribution of the multiple holes in each longitudinal row of suction holes in the longitudinal direction can be non-uniform.

[0009] For the entire thickness of the rotating tubular body, the cross-section passage of all the aforementioned suction orifices remains essentially constant. The exception is the presence of countersunk holes at the ends of the suction orifices (i.e., the portions located on the outer surface of the roller), where the countersunk holes are considered part of the orifice, providing a slight widening of the orifice.

[0010] Therefore, in the prior art suction rollers, the "effective surface" (i.e., the surface that performs the suction of the sheet and thus the adsorption) is the area of ​​the hole plus the countersunk hole (if present).

[0011] Furthermore, in multiple sets of holes, the suction holes in each longitudinal row can be formed by multiple holes that vary depending on the situation.

[0012] In existing rollers, the effective surface area is very small and insufficient for precise control of the capture, feeding, and release of sheets or webs formed of paper or other breathable materials, especially at high production speeds.

[0013] Furthermore, with such a limited effective surface area of ​​the hole, maintenance is very difficult, especially when it is necessary to remove blockages from the hole.

[0014] Examples of suction rolls with the aforementioned drawbacks are described in JP 2012 / 034867 and US 2007 / 228607. Specifically, JP 2012 / 034867 describes a transfer roll in the field of paper processing machinery that includes longitudinally arranged holes with a diameter of 5 mm, distributed as 3 to 10 holes per 230 mm. Therefore, the average suction surface per mm of length is less than 1 mm. 2 Therefore, it is insufficient to guarantee proper suction. Consequently, high productivity cannot be achieved without compromising product quality.

[0015] US 2007 / 228607 describes a suction roller located in a drying chamber for drying a membrane of polymeric material. Summary of the Invention

[0016] Therefore, the object of the present invention is to provide a suction roller for a paper processing machine that overcomes the shortcomings of existing rollers.

[0017] The specific object of the present invention is to provide a suction roller for a paper processing machine that simplifies and accelerates ordinary and extraordinary maintenance and repair, particularly the replacement of the provided gaskets.

[0018] Another object of the present invention is to provide a suction roller for a paper processing machine that improves suction at the same vacuum or suction level used to help sheet or flake products adhere to their outer surface.

[0019] Another object of the present invention is to increase the suction surface area on the outer surface of the suction roller, thereby distributing the vacuum or suction on the suction roller in a more efficient and effective manner.

[0020] These and other objectives are achieved by a suction roller for drawing out sheet-like products (e.g., webs or sheets of paper or other breathable materials) fed in the forward direction in a paper processing machine, the suction roller comprising: A rotating tubular body is configured to rotate about a longitudinal axis of rotation in a predetermined direction of rotation. The rotating tubular body has an outer surface and an inner surface, which are pneumatically connected by a plurality of suction channels arranged in a predetermined number of longitudinal rows. A suction chamber, defined inside the suction roller, is pneumatically connected to a device for generating an airflow. A suction dispensing device is configured to selectively pneumatically connect the suction chamber to at least one longitudinal row of suction channels of the plurality of suction channels at a predetermined angular position of the rotating tubular body, so that the processed sheet-like product is suctioned and adsorbed at the corresponding portion of the outer surface of the rotating tubular body. The main feature of the suction roller is that at least one of the suction channels in the longitudinal row has an average suction surface area greater than 1 mm per millimeter of length on the outer surface of the rotating tubular body. 2 .

[0021] Other features and related embodiments of the invention are set forth in the dependent claims.

[0022] Specifically, at least one of the aforementioned longitudinally arranged suction channels has an average suction surface area on the outer surface of the rotating tubular body that is greater than 1.2 mm per millimeter of length. 2 Advantageously greater than 1.5 mm per millimeter in length. 2 In one embodiment of the invention, the average suction surface area of ​​all longitudinally arranged suction channels on the outer surface of the rotating tubular body can be greater than 1 mm per millimeter of length. 2 Especially those with a length greater than 1.2 mm per millimeter. 2 Advantageously greater than 1.5 mm per millimeter in length. 2 .

[0023] Specifically, at least one of the plurality of suction channels has a first cross-sectional passage s1 and a second cross-sectional passage s2, the first cross-sectional passage having a first suction surface A1 at the outer surface of the rotating tubular body, and the second cross-sectional passage having a second suction surface A2 at the inner surface of the rotating tubular body.

[0024] In an embodiment of the present invention, the first suction surface area A1 of at least one suction channel is greater than the second suction surface area A2.

[0025] Specifically, at least one of the plurality of suction channels is divided into a plurality of suction orifices on the outer surface of the rotating tubular body. More specifically, each suction channel is provided with at least one outlet orifice on the inner surface of the rotating tubular body.

[0026] More specifically, at least one of the aforementioned plurality of suction channels may have a first total suction surface area (A) calculated by adding the suction surfaces of all the aforementioned plurality of suction orifices. tot The area of ​​the second suction surface is greater than that of the second suction surface, A2, i.e., A1>A2.

[0027] Specifically, at least one of the aforementioned multiple suction channels may be provided with a connecting portion, which is arranged to pneumatically connect the multiple suction orifices to the outlet orifice or each outlet orifice.

[0028] More specifically, the aforementioned connection portion may have a cross-sectional passage(s) that increases from the plurality of suction orifices toward the outlet orifice or each outlet orifice.

[0029] In one embodiment of the present invention, the aforementioned plurality of suction orifices of at least one suction channel have a total suction surface area (Atot) calculated by adding the suction surface areas of each suction orifice, and the total suction surface area is greater than 35 mm. 2 Advantageously greater than 50 mm 2 Preferably greater than 80 mm 2 .

[0030] Specifically, multiple insertion members can be provided, each insertion member having at least one of the aforementioned multiple suction channels. More specifically, each insertion member is arranged to removably engage with the aforementioned rotating tubular body.

[0031] In one embodiment of the present invention, each of the plurality of insertion members may include a body having at least the plurality of suction orifices adapted to be connected to the same suction channel during use.

[0032] In embodiments of the present invention, at least one of the aforementioned plurality of insertion members further includes at least one connecting conduit or chamber of a corresponding suction channel.

[0033] Specifically, the aforementioned device for generating airflow is pneumatically connected to the longitudinal suction chamber, and the device for generating airflow can be selected from: compressor; Centrifugal compressor; Fan; Centrifugal fan; Vacuum pump.

[0034] In one embodiment of the invention, the suction dispensing device may include a fixed tubular body coaxially mounted inside the rotating tubular body.

[0035] Specifically, the fixed tubular body may be provided with the aforementioned longitudinal suction chamber, which is pneumatically connected to a device for generating a predetermined airflow. More specifically, the fixed tubular body may be provided with at least one row of circumferential orifices, which are arranged at predetermined angular positions of the rotating tubular body to dynamically connect the longitudinal suction chamber to at least one row of the aforementioned suction channels each time.

[0036] Specifically, each of the aforementioned insertion members may be provided with a corresponding cover member, which has the plurality of suction orifices. More specifically, the size of each suction orifice may be designed to prevent the processed sheet-like product from extending beyond the outer surface of the rotating tubular body, while allowing the processed sheet-like product to be suctioned to a predetermined angle portion of the outer surface of the rotating tubular body.

[0037] According to another aspect of the invention, the paper processing machine includes at least one processing unit selected from: Folding or staggered folding unit, which is suitable for folding or staggering webs or multiple sheets according to a predetermined folding or staggered folding configuration; A cutting unit configured to cut a continuous web material into multiple sheets; A forward unit, which is arranged to advance the paper web or sheet along a predetermined forward direction; Or a combination of the above units; It includes at least the suction rollers described above.

[0038] Specifically, the fixed tubular body may also be provided with a second plurality of circumferential orifices, which are positioned along the longitudinal direction in the second row of the fixed tubular body.

[0039] Advantageously, the first plurality of circumferential orifices and the second plurality of circumferential orifices can be circumferentially staggered relative to each other. In this way, the first row of suction channels and the second row of suction channels can be pneumatically connected to the longitudinal suction chamber at the aforementioned predetermined angular positions of the rotating tubular body.

[0040] According to embodiments of the invention, the device for generating an airflow may have a main body integral with the fixed tubular body. More specifically, the device for generating an airflow may further include an impeller adapted to be housed in the main body and operatively connected to a motor for generating an airflow within a longitudinal suction chamber. In an advantageous embodiment, the aforementioned device for generating an airflow is arranged to generate an airflow at a predetermined pressure (Pi) less than atmospheric pressure.

[0041] Specifically, the rotating tubular body may also be provided with at least a third plurality of suction orifices arranged in a predetermined number of longitudinal rows. More specifically, the longitudinal rows or each of the first and second plurality of suction orifices may be positioned on the rotating tubular body to be pneumatically connected to the first plurality of circumferential orifices at the corresponding angular positions, while the longitudinal rows or each of the third plurality of suction orifices may be positioned on the rotating tubular body to be pneumatically connected to the second plurality of circumferential orifices at the corresponding predetermined angular positions. Attached Figure Description

[0042] The invention will now be described with reference to the accompanying drawings, through the following description of exemplary embodiments thereof, which are exemplary and not restrictive, wherein: Figure 1 A perspective side view of a first embodiment of the suction roller according to the present invention is shown schematically; Figure 2 schematically shows Figure 1 Longitudinal cross-section of a possible embodiment of the suction roller; Figure 3 An enlarged view of a portion of Figure 2 is shown schematically to highlight some technical features of the rotating tubular body of the suction roller in Figure 2. Figure 4 and Figure 5 A perspective side view schematically illustrates two possible alternative embodiments of the suction roller according to the invention; Figure 6 A perspective side view schematically illustrates a possible embodiment of a fixed tubular body that can be used in a suction roller according to the invention; Figure 7 schematically shows a longitudinal section of an alternative embodiment of the suction roller of Figure 2; Figure 8 An enlarged view of a portion of Figure 7 is shown schematically to highlight some technical features of the rotating tubular body of the suction roller in Figure 7. Figure 9The transverse cross section of the suction roller in Figure 7 is shown schematically; Figure 10 schematically shows a longitudinal section of another alternative embodiment of the suction roller of Figure 2; Figure 11 An enlarged view of a portion of FIG10 is shown schematically to highlight some technical features of the rotating tubular body of the suction roller of FIG10. Figure 12 Schematic illustration of what can be used Figure 10 and Figure 11 A top perspective view of the insertion member in an alternative embodiment of the suction roller; Figure 13 The cross-sectional view shown is based on arrow XIII-XIII. Figure 12 Insertion component; Figure 14 schematically shows a longitudinal section of another alternative embodiment of the suction roller of Figure 2; Figure 15 An enlarged view of a portion of Figure 14 is shown schematically to highlight some technical features of the rotating tubular body of the suction roller of Figure 14. Figure 16 The illustration shows what can be used in Figure 14 and Figure 15 A top perspective view of the insertion member in an embodiment of the suction roller; Figure 17 The cross-sectional view shown is based on arrows XVII-XVII. Figure 16 Insertion component; Figure 18 The illustration shows what can be used in Figure 14 and Figure 15 A top perspective view of an alternative embodiment of the insertion member in the embodiment of the suction roller; Figure 19 The cross-sectional view shown is based on arrow XIX-XIX. Figure 18 Insertion component; Figure 20 The illustration shows what can be used in Figure 14 and Figure 15 A top perspective view of another alternative embodiment of the insertion member in the embodiment of the suction roller; Figure 21 The cross-sectional view shown is based on arrow XXI-XXI. Figure 20 Insertion component; Figure 22 The illustration shows what can be used in Figure 14 and Figure 15 A top perspective view of a disassembled configuration of an alternative embodiment of the insertion member in the embodiment of the suction roller; Figure 23 The invention is schematically illustrated for use in Figure 1 A perspective side view of another alternative embodiment of the suction roller; Figure 24 The invention is schematically illustrated for use in Figure 6 A perspective side view of an alternative embodiment of the fixed tubular body; Figure 25 A perspective side view schematically illustrates another alternative embodiment of the insertion member that can be used in a suction roller according to the invention; Figure 26 A perspective side view of yet another alternative embodiment of the suction roller according to the invention is shown, wherein the ends of the suction channels have been removed to show some technical features; Figure 27 A perspective side view schematically illustrates yet another alternative embodiment of the insertion member that can be used in a suction roller according to the invention; Figures 28 to 30 Three different transverse sections of other embodiments of the suction roller according to the present invention are shown; Figure 31 A perspective side view of yet another alternative embodiment of the suction roller according to the present invention is shown; Figure 32 schematically shows a side view of the suction roller according to the present invention; Figure 33 and Figure 34 Enlarged views of two different parts of the suction roller in Figure 32 are shown to highlight some technical features; Figure 35 A side view of a folding unit with first and second suction rollers according to the present invention is shown schematically. Detailed Implementation

[0043] like Figure 1 The suction roller 1 according to the invention, schematically shown, is of the type used to feed sheet-like products 5 (e.g., webs or sheets of paper or other breathable materials such as nonwovens) along a forward direction, particularly in machines that process paper or similar products. The suction roller 1 includes a rotating tubular body 20 configured to rotate about a longitudinal axis of rotation 120 along a predetermined rotational direction. Figure 2 and Figure 3 As schematically shown, the rotating tubular body 20 has an outer surface 21 and an inner surface 22, which are pneumatically connected to each other by a plurality of suction channels 23 arranged in a predetermined number of longitudinal rows 3. Furthermore, the suction roller 1 is provided with a longitudinal suction chamber 16, which is defined inside the suction roller and pneumatically connected to a device 50 for generating an airflow. Figure 4 This can be illustrated schematically as a device suitable for generating an airflow at a predetermined vacuum level, such as a vacuum pump. According to the invention... Figure 5In the alternative embodiment schematically shown, the device 50 for generating the airflow can be arranged to create a pressure jump in the airflow 55 between the suction zone and the pump zone. Such a device is, for example, a compressor (e.g., a centrifugal compressor, axial compressor, or rotary compressor) or a fan (particularly a centrifugal fan, axial fan, or other known type). In this case, the device 50 is advantageously connected to the longitudinal suction chamber 16 in the suction zone to generate a pressure less than atmospheric pressure within the longitudinal suction chamber 16, and a greater pressure downstream of the device 50 for generating the airflow (i.e., in the pump zone). In other words, the device 50 for generating the airflow generates an airflow 55 that enters the suction roller 1, passes through the device 50 for generating the airflow, and exits through the pump orifice of the device 50 at a pressure greater than atmospheric pressure. Specifically, the device 50 for generating the airflow can be connected to the aforementioned longitudinal suction chamber 16 via a conduit 60.

[0044] In particular, Figure 1 As in Figure 2, the longitudinal suction chamber 16 is located inside the fixed tubular body 10, which is located inside and coaxial with the rotating tubular body 20. The rotating tubular body 20 is configured to rotate coaxially about the fixed tubular body 10. For this purpose, a mechanical connection can be provided between the fixed tubular body 10 and the rotating tubular body 20, which is achieved by ball bearings, brass bushings, or other means that allow them to move relative to each other. For example, ball bearings can be positioned at both ends of the rotating tubular body 20 between the fixed tubular body 10 and the rotating tubular body 20. In other cases, when the axial length is very long, for example greater than 2 meters or preferably greater than 2.80 meters, another means for reciprocating motion can be positioned at an intermediate position included between the two ends of the rotating tubular body 20.

[0045] Then, a suction distribution device 40 is provided, which is configured to selectively pneumatically connect the suction chamber 16 to at least one suction channel 23 of the longitudinal row 3 at a predetermined angular position of the rotating tubular body 20. In this way, the sheet-like product 5 being processed (particularly sheets or webs of paper or other breathable materials such as nonwoven fabrics) is suctioned and adsorbed onto the corresponding portion of the outer surface 21 of the rotating tubular body 20.

[0046] In one embodiment of the present invention, such as Figure 6Schematably shown, the suction dispensing device 40 includes a fixed tubular body 10 coaxially mounted within a rotating tubular body 20. The fixed tubular body 10 has an outer surface 11 and an inner surface 12. Specifically, the fixed tubular body 10 has the aforementioned longitudinal suction chamber 16, which is pneumatically connected to a device 50 for generating a predetermined airflow 55. More specifically, the fixed tubular body 10 has a first plurality of circumferential orifices 15 positioned along at least a first longitudinal row 13 and arranged such that the outer surface 11 is pneumatically connected to the inner surface 12, and thus, each time at the aforementioned predetermined angular position of the rotating tubular body 20, the longitudinal suction chamber 16 is pneumatically connected to a suction channel 23 of at least one longitudinal row 3. Specifically, each suction channel 23 of the longitudinal row 3 is aligned with a corresponding circumferential orifice 15 for pneumatic connection with a suction chamber 16 at the circumferential orifice 15.

[0047] Specifically, when the device 50 for generating the airflow is not a vacuum pump, it can be configured to move the airflow between an inlet 16a and an outlet 16b through a longitudinal suction chamber 16, the outlet of which is directly connected to the device 50 or the conduit 60 for generating the airflow. Preferably, the cross-sectional area of ​​the inlet 16a can be smaller than the cross-sectional area of ​​the outlet 16b. In this way, during the rotation of the rotating tubular body 20 about the rotation axis 120, the processed sheet-like product can be drawn in and adsorbed onto the outer surface 21 at a predetermined angular position. When the device 50 for generating the airflow is a vacuum pump, the inlet 16a is not provided, or the inlet 16a is closed, so as not to lose the vacuum level inside the longitudinal suction chamber 16.

[0048] In an alternative embodiment of the invention, referred to as internal tube aspiration, such as Figure 9 As schematically shown, the suction dispensing device 40 may include a first sealing element 18a and a second sealing element 18b, which are integrally formed with the fixed tubular body 10 from opposite sides relative to the orifice 15, in which case the orifice 15 is longitudinally disposed on the fixed tubular body 10. Specifically, the first sealing element 18a and the second sealing element 18b are longitudinally positioned on the fixed tubular body 10. Specifically, at both ends of the fixed tubular body 10, circumferential seals may be provided in the region between the outer surface 11 of the tubular body 10 and the inner surface 22 of the rotating tubular body 20. In this way, a suction chamber is provided defined by the first sealing element 18a and the second sealing element 18b, the outer surface 11 of the fixed tubular body 10, the inner surface 22 of the rotating tubular body 20, and the circumferential seals (when present). In the case where the device 50 for generating the airflow is a vacuum pump, advantageously, the inlet 16a is not provided, or can be configured to be closed, so as not to lose the vacuum level within the longitudinal suction chamber 16.

[0049] In this configuration, the suction channel 23 is pneumatically connected to the suction chamber 16 at an angle defined by the first sealing element 18a and the second sealing element 18b.

[0050] In another alternative embodiment of the invention, the suction dispensing device 40 can be implemented as a so-called "bell" device, wherein one or more longitudinal rows 3 of the suction channels 23 are pneumatically connected to corresponding longitudinal suction chambers 16 located inside the rotating tubular body 20. Specifically, the longitudinal suction chambers 16 3 are disposed within the rotating tubular body 20 and arranged longitudinally along the axial direction of the suction roller 1. More than one longitudinal suction chamber 16 may be provided in the rotating tubular body 20. The longitudinal suction chambers 16 are pneumatically connected to the suction dispensing device 40, which is located at one or both ends of the suction roller 1, preferably outside the rotating tubular body 20. In this case, i.e., when the suction is of the "bell" type, it should be understood that the inner surface 22 of the rotating tubular body 20, which is pneumatically connected to the outer surface 21 by the multiple suction channels 23, is the side associated with each longitudinal suction chamber 16. The suction distribution device 40 has an arc-shaped suction channel, such that during the rotation of the rotating tubular body 20, the longitudinal suction chamber 16 only performs suction when it moves within the arc-shaped suction channel. The suction distribution device 40 is further connected to a device 50 for generating an airflow. Such suction distributions are known in the art and are described, for example, in US6488194. The suction roller 1 can have a mixed suction type, i.e., one or more rows of holes associated with a "bell-shaped" type suction system, and another row or more rows of holes associated with an "inner tube" type suction system as described above, or with reference to... Figure 6 This type of suction system is associated with, for example, EP1457444B2.

[0051] According to the present invention, in the case of suction being of the "bell-shaped" type or the "inner tube" type, and as shown in Figures 2 to 30, the suction is performed in accordance with the present invention. Figure 6 In its construction, the average suction surface area of ​​the multiple suction channels 23 on the outer surface 21 of the rotating tubular body 20 is greater than 1 mm per millimeter of length. 2 Specifically, the average suction surface area can be greater than 1.2 mm per millimeter of length. 2 More specifically, greater than 1.5 mm per millimeter in length. 2 / mm, advantageously greater than 2.0 mm per millimeter length. 2 Preferably, the length is greater than 3.0 mm per millimeter. 2 In other words, the multiple suction channels 23 have a row of holes along the outer surface 21 or an average distribution along the suction surface area of ​​a single suction channel 23, so as to have a length greater than 1.5 mm per millimeter.2 Advantageously greater than 2.0 mm per millimeter in length. 2 Preferably, the length is greater than 3.0 mm per millimeter. 2 The suction area.

[0052] It should be noted that for "length per millimeter (mm)" 2 The statement can be understood as follows: the aforementioned suction surface area can be calculated with reference to the length of the suction roller 1 or the rotating tubular body 20. Specifically, the average suction surface area or the average distribution of the suction surface area of ​​a row of suction channels 23 can be calculated by adding up the cross-sectional areas of all suction channels 23 located on the outer surface 21 and dividing the sum by the longitudinal length L of the rotating tubular body 20. The cross-section of each suction channel 23 on the outer surface 21 may also include the machining of countersunk holes (if present).

[0053] To further illustrate this concept, Figure 32 illustrates, as an example, the case of the suction roller 1, where, for clarity, a single longitudinal row 3 of suction channels 23 is shown. More specifically, in Figure 32, the suction roller 1 has a predetermined length L, for example, equal to 1600 mm, and the aforementioned longitudinal row 3 of suction channels 23 has a predetermined number of suction channels 23. For example, the longitudinal row 3 may include 61 channels with a surface area of ​​35 mm². 2 The suction channels 23, for simplicity, are shown only in Figure 32 in some of them, as well as a predetermined number of other suction channels 23', for example, with different suction surface areas (e.g., suction surface area equal to 30 mm²). 2 The 10 suction channels 23' of the longitudinal row 3 are therefore, in this case, the total surface area of ​​the longitudinal row 3 is equal to 2435 mm. 2 Dividing by the aforementioned length L, the average suction surface of row 3 is determined to be 1.52 mm per millimeter of length. 2 .

[0054] In other embodiments of the invention, it is generally possible to have a group of a defined number of suction channels 23 and 23', for example, suction surfaces at the outer surface 21 of a circle or substantially a circle. Figure 33 and Figure 34In the case where the first suction channel 23 has a diameter d1 and the second suction channel 23' has a diameter d2, with d2 < d1. However, as will be readily understood by those skilled in the art, within the same inventive concept, the possible combinations of the size of the suction channels 23 and the suction surface area are not limited. In these cases, the present invention provides the case where all of the aforementioned suction channels 23 of the longitudinal row 3 have the same suction surface area, the opposite case where the suction channels 23 all have different suction surface areas relative to each other, and a mixed case where the suction channels 23 are arranged in different groups, each group having a predetermined number of suction channels 23 with a predetermined suction surface.

[0055] The technical solution provided by the present invention particularly allows for an effective suction action of the processed sheet-like product 5 to be performed regardless of the type of the suction distribution device 40. Specifically, compared with the technical solutions of the prior art, the effective surface of the outer surface 21 of the rotary tubular body 20 (i.e., the part that holds the processed sheet-like product 5) is increased, which allows for the adsorption of the sheet or web to be distributed over a larger surface on the outer surface 21 of the rotary tubular body 20, which is a greater distribution, and thus a stronger and more stable capture is obtained compared with the suction rollers of the prior art. In addition, compared with the prior art, without changing the starting and ending points of the suction, an increase in the useful surface for holding the sheet-like product 5 is obtained, and there is no significant loss of the vacuum (or generally the suction degree) generated by the device 50 for generating the air flow, that is, at the same installed suction force.

[0056] Specifically, as shown in FIG. 2, Figure 3 and FIGS. 7 to Figure 11 as shown, each of the suction channels 23 among the above-mentioned plurality of suction channels may have a first cross-sectional passage s1 and a second cross-sectional passage s2. The first cross-sectional passage s1 has a first suction surface area A1 at the outer surface 21 where there is a suction orifice or inlet orifice 24, and the second cross-sectional passage s2 has a second suction surface area A2 at the inner surface 22. Specifically, at least one of the suction channels 23 among the aforementioned plurality of suction channels is configured such that the first suction surface area A1 is greater than the second suction surface area A2 where there is an outlet orifice 25. Specifically, as Figures 3 to 11 shown, the suction channel 23 may have at least a part of its cross-sectional area increasing in the direction outward from the suction roller 1. The increase in the cross-sectional area of the suction channel 23 is different from the prior art where the hole has a countersink, because this machining is considered to be surface machining, that is, it involves the hole at the outer surface 21 rather than the suction channel 23. In this way, the useful surface at the outer surface 23 (i.e., the surface suitable for holding the sheet-like product 5 by suction) is larger than that of the rollers of the prior art.

[0057] In a preferred embodiment of the invention, for example in Figure 1 Figure 7 Figure 8 and Figure 9 As schematically shown, at least one of the aforementioned suction channels 23 may have a plurality of suction orifices 24 on its outer surface 21. Optionally, the plurality of suction orifices 24 may correspond to the plurality of suction channels on the outer surface 21. Specifically, in this case, at least one suction channel 23 may have a connecting portion 26 arranged to pneumatically connect the plurality of suction orifices 24 to the outlet orifice 25 or each outlet orifice 25. For example, the connecting portion 26 may have a cross-sectional passage s that decreases from the plurality of suction orifices 24 toward the outlet orifice 25. The outlet orifice 25 is located at the end of the suction channel 23 opposite to the plurality of suction orifices 24. In practice, the suction channel 23 has a variable cross-sectional area, i.e., at least a portion of it increases in the direction from the suction roller 1 toward the outer surface 21 of the rotating tubular body 20.

[0058] Specifically, the multiple suction orifices 24 of the same suction channel 23 have a total suction surface area Atot, which is calculated by adding the suction surface areas of each suction orifice 24 and is greater than 30 mm. 2 Preferably greater than 50 mm 2 Advantageously greater than 80 mm 2 .

[0059] Multiple suction orifices 24 form a suction grid that prevents the sheet-like product 5 from being partially drawn into the suction roller 1 and allows for the extension of a suction surface suitable for holding a portion (e.g., the head and / or tail or middle portion) of the sheet-like product 5. In fact, compared to the prior art, the suction surface area is larger, and in some cases, it is able to at least partially draw the sheet-like product 5, which would lead to malfunctions and blockages.

[0060] In Figure 10 to Figure 17 In the schematic embodiment of the invention, the suction roller 1 includes a plurality of insertion members 30, which are advantageously removably arranged to engage the rotating tubular body 20, for example, by a defined number of screws or similar blocking elements at corresponding seats 28 formed in the rotating tubular body 20. In this case, in the seats 28, the ends of one or more suction channels 23 are closer to the outer surface 21 so as to pneumatically connect the insertion members 30 to the suction channels 23, and thus to the aforementioned longitudinal suction chamber 16 or one of the longitudinal suction chambers 16. Specifically, each insertion member 30 includes a body 31 in which at least the aforementioned plurality of suction orifices 24 (Figures 10 to 11) are provided. Figure 13One or more suction channels 23 may be pneumatically connected to each insert member 30. Specifically, suction channels suitable for suctioning the same portion (e.g., the middle portion, the tail, or the head) of the sheet-like product 5 in the same longitudinal row 3 may be connected to the same insert member 30. In other cases, suction channels suitable for suctioning different portions (e.g., the head and tail of the sheet-like product 5, or only the middle portion) may be connected to the same insert member 30. In a preferred embodiment, each of the plurality of insert members 30 includes a plurality of suction orifices 24 and a connecting portion 26 of a corresponding suction channel 23 (Figures 14 to 15). Figure 17 In this case, the insertion member may include a suction channel 23 or a corresponding connecting portion 26 of the suction channel 23, the cross-sectional area of ​​which is not constant, preferably at least a portion of which increases in the direction from the side contacting the seat 28 toward the plurality of suction orifices 24 (i.e., toward the outer surface 21 of the rotating tubular body 20). Furthermore, in this case, it should be understood that at least the increased portion is considered to be without countersunk holes; that is, countersunk hole processing present on prior art holes is considered a surface processing of the rotating tubular body 20 and therefore not part of the suction channel 23 or the connecting portion 26. In other embodiments, the insertion member 30 may simply have a hollow body, i.e., a suction chamber is formed inside the insertion member 30. The insertion member may include a suction channel 23 or a corresponding connecting portion 26 of the suction channel 23, the cross-sectional area of ​​which is not constant, preferably at least a portion of which increases in the direction from the side contacting the seat 28 toward the plurality of suction orifices 24 (i.e., toward the outer surface 21 of the rotating tubular body 20). It should be understood that at least the majority of the hole is considered to be without countersunk holes, that is, the countersunk hole processing present in the prior art hole is considered to be the surface processing of the rotating tubular body 20 and therefore not part of the suction channel 23.

[0061] exist Figure 18 and Figure 19 In one embodiment of the invention, schematically illustrated, the insertion member 30, or the body 31 of each insertion member 30, may include a portion of a base 32 arranged to engage with the rotating tubular body 20 and a cover portion 33 having the aforementioned plurality of suction orifices 24. More specifically, the cover portion 32 and a portion of the base 31 are advantageously arranged to engage with each other in a detachable manner, for example by screws, bolts, or similar detachable engagement elements.

[0062] Similar to what has been described above, the insertion member 30 according to the invention may have a first cross-sectional passage s1 and a second cross-sectional passage s2. The first cross-sectional passage has a first suction surface area A1 at the outer surface 21 where the suction orifice or inlet orifice 24 is located, and the second cross-sectional passage has a second suction surface area A2 on the side in contact with the seat portion 28. In a non-limiting embodiment of the invention, the second cross-sectional passage s2 located at the corresponding suction channel 23 may have a surface area substantially equal to the cross-sectional area of ​​the corresponding suction channel 23. In this case, the suction channel preferably has, but is not limited to, a constant cross-sectional area, for example, because it is formed by drilling a hole in the rotating tubular body 20. In other cases, the second suction surface area A2 may have a surface area different from the cross-sectional area of ​​the corresponding suction channel 23, preferably larger than the cross-sectional area of ​​the corresponding suction channel.

[0063] In an alternative embodiment of the invention, the insertion member 30 may be pneumatically connected to more than one suction channel 23. In this case, there is more than one channel portion s2, preferably each located at a corresponding suction channel 23.

[0064] From Figures 16 to 19 In the schematically illustrated embodiment, each insertion member 30 may be provided with at least a first plurality of suction ports 24a pneumatically connected to a first outlet port 25a, and a second plurality of suction ports 24b pneumatically connected to a second outlet port 25b. The first outlet port 25a and the second outlet port 25b may be arranged to be pneumatically connected to the longitudinal chamber 16 at a predetermined angular position of the rotating tubular body 20 or at corresponding different predetermined angular positions of the rotating tubular body 20. The first outlet port 25a and the second outlet port 25b may be arranged to be pneumatically connected to a corresponding suction channel 23, which in turn is pneumatically connected to the longitudinal suction chamber 16. Specifically, the first plurality of suction ports 24a of the insertion member 30 may be adapted to hold the end or tail of the sheet being processed under operating conditions, and the second plurality of suction ports 24b may be adapted to hold the beginning or head of another sheet. In another case, the first plurality of suction orifices 24a of the insertion member 30 may be adapted to hold a first portion of the sheet adjacent to the middle portion of the sheet being processed, and the second plurality of suction orifices 24b may be adapted to hold a second portion of the sheet adjacent to the middle portion of the sheet being processed.

[0065] Specifically, at least one of the aforementioned plurality of insert members 30 may be provided with at least a first plurality of connecting portions 26a and a second plurality of connecting portions 26b. These may be separated by a partition wall 27. Figure 22 Multiple connecting portions 26a and 26b may have different suction surface areas A1 at their outer surfaces 21, and / or may have different second suction surface areas A2 on the side contacting the seat portion 28. For example, as Figure 22 As shown, the first connecting portion 26a may be larger than the connecting portion 26b and may be placed at the suction port 24a suitable for holding the head of the sheet 5, while the connecting portion 26b may be placed at the suction port 24b suitable for holding the tail of the sheet 5.

[0066] In particular, such as Figure 18 , Figure 22 and Figure 23 As shown, a lower portion 35 can be provided between the first plurality of suction orifices 24a and the second plurality of suction orifices 24b, particularly longitudinally along the corresponding insertion member 30. In this way, mechanical interference with elements protruding from the outer surface of the roller located upstream of the suction roller 1 can be avoided under operating conditions. These elements are, for example, cutting blades for cutting a continuous web formed of sheet material into a plurality of sheets of predetermined length, or insertion wedges (not shown in the figure for simplicity).

[0067] According to one possible embodiment of the present invention, at least one of the plurality of insert members 30 may be formed by a molding process of a plastic material (in particular ABS, or high-density polyethylene, or similar plastic material) or by a molding or deposition process of a metal material.

[0068] like Figure 24 As schematically shown, in an alternative embodiment provided by the present invention, the fixed tubular body 10 may be provided with a first plurality of circumferential openings 15a and a second plurality of circumferential openings 15b respectively positioned along the first longitudinal row 13 and the second longitudinal row 14. Specifically, the circumferential portions provided with the circumferential openings 15a and 15b are configured to be circumferentially staggered with each other. More specifically, as Figure 24 As shown, the circumferential portions provided with circumferential openings 15a and 15b can partially overlap each other. In other words, the first and second plurality of circumferential openings 15a and 15b of the fixed tubular body 10 can be distributed on a first longitudinal row 13 and a second longitudinal row 14 arranged side by side and partially circumferentially in the longitudinal direction. More specifically, each circumferential opening (or arcuate opening) 15a of the first plurality of circumferential openings can be positioned close to the corresponding circumferential opening (or arcuate opening 15b) of the second plurality of circumferential openings, for example, at a distance between them of 1 mm and 150 mm, advantageously between 1.5 mm and 100 mm, preferably between 1.5 mm and 50 mm, for example, between 2 mm and 50 mm.

[0069] In this configuration, a first set of insertion members 30 and a second set of insertion members 30' as described above are advantageously provided. Specifically, as described above, the first set of insertion members 30 may be provided with at least a first plurality of suction orifices 24a, adapted to suction the starting portion or head of the processed sheet-like product 5 and / or adapted to suction the end or tail portion. The insertion members 30 may also be provided with a second plurality of suction orifices 24b, adapted to suction the end or tail portion of another sheet-like product 5. The insertion members 30' may be provided with at least a third plurality of suction orifices 24c, adapted to hold the middle portion of the sheet-like product 5.

[0070] For example, in this case, the suction orifices 24a and 24b of the first set of insertion members 30 can be arranged to hold the processed product 5 by suction through the circumferential orifice 15a of the first row 13, and the suction orifice 24c of the second set of insertion members 30' can be arranged to hold the processed product 5 by suction through the circumferential orifice 15b of the second row 14.

[0071] More specifically, especially Figure 26 As can be seen, the ends of the suction channels 23 have been removed to show some technical features of the present invention. The first plurality of suction channels 23a and the second plurality of suction channels 23b are configured to be associated with the first set of insertion members 30, which are formed in the rotating tubular body 20 and pneumatically connected to the longitudinal suction chamber 16 at a first predetermined angular position of the rotating tubular body 20. The third plurality of suction channels 23c are configured to be associated with the second set of insertion members 30', which are formed in the rotating tubular body 20 and pneumatically connected to the longitudinal suction chamber 16 at a second predetermined angular position of the rotating tubular body 20.

[0072] exist Figure 27 In another alternative embodiment of the invention, schematically illustrated, the second set of insertion members 30' may further be provided with a fourth plurality of suction orifices 24d and corresponding fourth connecting portions 26d. Specifically, the third connecting portion 26c and the fourth connecting portion 26d may be separated by a partition wall 27'. Specifically, when the insertion member 30' is used to hold the middle portion of the sheet 5, the third connecting portion 26c can hold the first portion of the sheet adjacent to the middle portion of the sheet being processed, and the fourth connecting portion 26d can hold the second portion of the sheet adjacent to the middle portion of the sheet being processed.

[0073] Specifically, the openings of the connecting parts 26a-26c can be in the form of a basic rectangle, or more specifically, a rectangle with rounded corners.

[0074] like Figure 28 and Figure 29The schematic cross-sectional view shows the presence of a first, second, third, and fourth plurality of suction orifices 24a-24d and corresponding connecting portions 26a-26d. However, as will be readily understood by those skilled in the art, it is also effective when only some of the plurality of suction orifices 24a-24c are present. The first set of insertion members 30 and the second set of insertion members 30' alternate with each other along the periphery of the rotating tubular body 20 (and thus along the periphery of the suction roller 1), such that the insertion members 30 are adapted to hold the head and tail of the sheet-like material 5, and the insertion members 30' are adapted to hold the middle portion of the sheet-like material 5.

[0075] Specifically, the first group of insert members 30 and the second group of insert members 30' are arranged in predetermined longitudinal rows 3a and 3b, respectively. Figure 28 and Figure 29 In the schematically illustrated embodiment, the rotating tubular body 20 has a first plurality of suction channels 23a and 23b in 5 rows 3a and a second plurality of suction channels 23c and 23d in 5 rows 3b. However, the number of rows in the rotating tubular body 20 is typically different and is selected according to the production or functional requirements of the machine using the suction roller 1 of the present invention. Typically, the suction roller 1 (especially in the case of a folding roller or a cutting roller) has a diameter equal to a multiple of the desired length of the sheet-like product 5. The number of sheets that can be placed on the suction roller 1 determines the number of longitudinal rows 3a and 3b.

[0076] There is also the possibility that the head and tail (or alternatively, the middle portion) of the processed sheet-like product 5 can be drawn by the suction roller 1 according to the invention, so as to adsorb it onto the outer surface 21 of the rotating tubular body 20 by a different suction system (e.g., a suction system commonly referred to as a "bell-shaped" system, or a suction system of the type described in EP1457444B1). For example, it can be done by a suction system as described in EP1457444B1, or according to reference to Figures 2 to 3. Figure 3 or Figure 6 The system described herein adsorbs the middle portion of a sheet-like product or a processed sheet 5, while a "bell-shaped" system holds the head and tail of the processed sheet-like product 5. Depending on production needs, the suction and dispensing device 40 described so far can be combined to hold the head 6, tail 7, or middle portion 8 of the sheet-like product 5 (e.g., a sheet).

[0077] In accordance with the present invention and Figure 30In another alternative embodiment schematically shown, the suction dispensing device 40 may include a plurality of sealing elements, such as a first sealing element 29a and a second sealing element 29b integral with (particularly longitudinally positioned on) the rotating tubular body 20. Sealing elements 29a and 29b of the plurality of sealing elements may be associated with at least one row of the aforementioned suction channels 23 and may be laterally positioned relative to the suction channels to pneumatically connect the outer surface 21 of the rotating tubular body 20 to the longitudinal suction chamber 16 at a predetermined angular position. In this case, the longitudinal suction chamber 16 is located within the fixed tubular body, and the suction angular position is determined by the angular position of the orifice 15, which in this case is not annular but longitudinally shaped. In practice, the suction channels 23 include seals 29a and 29b that move and rotate together with the rotating tubular body 20, which is consistent with… Figure 9 The technical solutions described in the text are different. Figure 9 In this case, the longitudinal seal fixedly arranged on the fixed tubular body 10 is associated with the orifice 5, which is also longitudinal in shape rather than annular.

[0078] The configuration described for the suction channel 23 and / or insertion member 30 can be applied independently of the suction dispensing device 40, i.e., with Figure 6 The first embodiment shown is also effective, in which case suction is Figure 9 The so-called "inner tube" type shown is either the "bell-shaped" type or... Figures 24 to 26 The technical solution shown, or Figure 30 The technical solutions, or combinations thereof, can be applied regardless of the type of device 50 used to generate the airflow. In fact, regardless of the suction distribution system 4, the adsorption of the sheet-like product 5 is improved due to better diffusion of the suction force on the outer surface 21 obtained by using the suction surface and / or suction channel described so far.

[0079] The invention is also fully effective when only a portion of the suction channel 23 of the longitudinal row 3 is provided, and when only a portion of the suction channel 23 of the longitudinal row 3 is provided, because in some cases, it is sufficient to improve the adsorption of the processed sheet on the outer surface of the suction roller 1 for only a portion of the axial length of the suction roller 1 or for only a portion of the processed sheet. For example, depending on the type of product to be produced and the type of material or paper being processed, the adsorption of only the middle portion of the sheet, or only the head or tail portion of the sheet, or a combination thereof, can be improved.

[0080] according to Figure 31In another embodiment of the invention, schematically illustrated, the device 50 for generating an airflow may include a body 51, in which an impeller 52 may be mounted, as schematically shown in the figure. The impeller 52 may be operatively connected to a motor 56 to rotate it about a rotation axis.

[0081] Still refer to Figure 31 This embodiment is also applicable to... Figures 1 to 30 In other embodiments of the suction roller 1 shown, at least one pressure sensor 80 may be provided for detecting the pressure within the longitudinal suction chamber 16. Specifically, the pressure sensor 80, or each pressure sensor, is also arranged to send a corresponding pressure signal P(ti) to the control unit 300. Advantageously, this is arranged to control the device 50 for generating the airflow 55, particularly the motor 56 of the device, such as a vacuum pump, compressor, or fan, based on the received pressure signal P(ti).

[0082] Specifically, at least first and second counter-rotating suction rollers 1 may be installed at the folding or staggering folding unit, which is configured to fold or stagger webs or multiple sheets according to a predetermined folding or staggering folding configuration.

[0083] As described above, the suction roller 1 can also be installed at the cutting unit, which is configured to cut the web of continuous web material into multiple sheets so that it can move downstream of the aforementioned cutting unit.

[0084] In the embodiments provided by the present invention, as described above, the suction roller 1 can be installed at the forward unit, which is configured to advance the paper web or sheet along a predetermined forward direction.

[0085] When the product is a sheet of sheet material (e.g., paper or other breathable material), the sheet has a head, a tail, and a middle portion between the head and tail. The suction roller 1 may include multiple suction channels 23: at least one suction channel 23' in a first longitudinal row 3', arranged to suction the head 6 of the sheet 5 onto the outer surface; at least one suction channel 23'' in a second longitudinal row 3'', arranged to suction the tail of the sheet 5 onto the outer surface 21a; and at least one suction channel 23''' in a third longitudinal row 3''', arranged to suction the middle portion 8 of the sheet 5 onto the outer surface. In this case, the average suction surface area of ​​the suction channels 23 in at least one of the first, second, and third longitudinal rows 3''' is preferably greater than 1.5 mm. 2 .

[0086] In addition, as described above, the suction roller 1 can also be mounted on a folding unit configured to fold or stagger the web or sheet of paper or other breathable material according to a predetermined folding and / or staggered folding configuration.

[0087] Specifically, in Figure 35 In the schematic illustration, a first suction roller 1a and a second suction roller 1b are mounted at a folding or staggered folding unit 100. Each suction roller 1a and 1b advantageously includes: at least a first longitudinal row 3'''a, arranged to suction, in addition to the middle portion 8a of the first sheet 5a, the head 6b of the second sheet 5b overlapping the first sheet 5a at the folding or staggered folding region 105 located between the two rollers 1a and 1b; and at least a second longitudinal row 3'''b, arranged to suction, in addition to the middle portion 8a of the first sheet 5a, the tail portion 7c of the third sheet 5c overlapping the first sheet 5a. In this case, at least the first longitudinal row 3'''a and / or at least the second longitudinal row 3'''b of the first and / or second suction rollers 1a and 1b have a length greater than 1 mm per millimeter. 2 (Advantageously greater than 1.5 mm per millimeter in length) 2 The average suction surface area. Although in Figure 35 In this configuration, the start-up or stop of the suction channels 23 of the longitudinal rows 3'''a and 3'''b is operated by the suction distribution device 40, which includes a first sealing element 18a and a second sealing element 18b. The first and second sealing elements are integrally formed with the fixed tubular body 10a or 10b from opposite sides relative to the orifices 15a or 15b. The start-up or stop of the suction channels 23 of the longitudinal rows 3' and 3'' is operated by a "bell-shaped" system. However, it will be readily understood by those skilled in the art that other operating devices may also be used for the longitudinal rows 3' and 3'' and / or the third longitudinal rows 3'''a and 3'''b.

[0088] According to another aspect of the invention, for example in a staggered folding machine, the angular position of the fixed tubular body 10 can be changed to adjust or regulate the start and end of suction in the suction channels 23, 24, and 25 (if present). The adjustment angle of the fixed tubular body 10 can be operated by an actuator connected to one end of the fixed tubular body 10. Adjustments can be made via commands given through an HMI (Human Machine Interface) during both the testing and operational phases of the staggered folding machine.

[0089] Optionally, the central control unit can be programmed to automatically change the angular position of the fixed tubular body 10 based on one or more operating parameters, such as the sheet feed speed, the sheet weight, the number of packages produced per minute by the staggered folding machine, and the sheet permeability. For example, the control unit can be programmed to cause the start and / or end of suction in the suction channels 23, 24 and / or 25 and / or 26 of the suction roller 1 to occur earlier when the sheet feed speed increases, and conversely, to cause the start and / or end of suction to occur later when the sheet feed speed decreases. Thus, the change in angle (and the resulting earlier or later start and / or end of suction in the suction channels 23, 24 and / or 25) can occur gradually during the machine's operation. This gradual change can be continuous or a speed step (i.e., for each predetermined increase or decrease in the sheet feed speed, the fixed tubular body 10 rotates clockwise or counterclockwise at the desired angle). For example, the angular position of the fixed tubular body 10 can be changed by increasing or decreasing the sheet feed speed by 50 m / min. The steps of the speed and rotation angle of the fixed tubular body 10 can be changed according to the product and / or the feed speed. The control unit can be programmed to change the delay or advance by rotating the fixed tubular body 10 at a speed threshold, that is, to change the angular position of the fixed tubular body 10 once the predetermined sheet feed speed is reached.

[0090] The foregoing description of specific embodiments fully discloses the invention from the inventive concept, enabling others to modify and / or adapt various applications of such embodiments by applying present knowledge without further research and without departing from the invention. Therefore, it should be understood that such adaptations and modifications must be considered equivalents of the specific embodiments. Consequently, apparatus and materials for implementing 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 suction roller (1) for suctioning a sheet-like product (5) fed in the forward direction in a paper processing machine, the suction roller (1) comprising: A rotating tubular body (20) is configured to rotate about a longitudinal axis of rotation (120) in a predetermined direction of rotation. The rotating tubular body (20) has an outer surface (21) and an inner surface (22). The outer surface and the inner surface are pneumatically connected to each other by a plurality of suction channels (23) arranged in a predetermined number of longitudinal rows (3). The suction chamber (16) is defined inside the suction roller (1) and is pneumatically connected to a device (50) for generating an airflow. A suction dispensing device (40) is configured to selectively pneumatically connect the suction chamber (16) to the suction channel (23) of at least one longitudinal row (3) at a predetermined angular position of the rotating tubular body (20) so that the processed sheet-like product (5) is suctioned and adsorbed onto the corresponding portion of the outer surface (21) of the rotating tubular body (20). The suction roller (1) is characterized in that at least one of the longitudinal rows (3) of the suction channels (23) has a length greater than 1 mm per millimeter at the outer surface (21) of the rotating tubular body (20). 2 The average suction surface area.

2. The suction roller (1) for the sheet-like product according to claim 1, wherein the average suction surface is greater than 1.2 mm per millimeter of length. 2 .

3. The suction roller (1) for the sheet-like product according to claim 1, wherein the average suction surface is greater than 1.5 mm per millimeter of length. 2 .

4. A suction roller (1) for a sheet product according to one or more of the preceding claims, wherein the sheet product (5) is a sheet comprising a head (6), a tail (7), and an intermediate portion (8) located between the head (6) and the tail (7), and wherein the plurality of suction channels (23) comprises: At least a first longitudinal row (3') of suction channels (23') is arranged to suction the head (6) onto the outer surface (21); at least a second longitudinal row (3'') of suction channels (23'') is arranged to suction the tail (7) onto the outer surface (21); and at least a third longitudinal row (3''') of suction channels (23''') is arranged to suction the middle portion (8) of the sheet (5) onto the outer surface (21), and wherein the suction channels (23) of at least one of the first longitudinal row (3'), the second longitudinal row (3'') and the third longitudinal row (3''') have the average suction surface.

5. The suction roller (1) for a sheet product according to claim 4, wherein at least the suction channel (23) of the third longitudinal row (3''') has the average suction surface.

6. A suction roller (1) for a sheet-like product according to one or more of the preceding claims, wherein each suction channel (23) has a first cross-sectional passage (s1) and a second cross-sectional passage (s2), the first cross-sectional passage having a first suction surface area (A1) at the outer surface (21) of the rotating tubular body (20), the second cross-sectional passage having a second suction surface area (A2) at the inner surface (22) of the rotating tubular body (20), and wherein at least one suction channel (23) is configured such that the first suction surface area (A1) is greater than the second suction surface area (A2).

7. The suction roller (1) according to claim 6, wherein at least one suction channel (23) of the plurality of suction channels is divided into a plurality of suction orifices (24) at the outer surface (21) of the rotating tubular body (20), and wherein at least one suction channel (23) of the plurality of suction channels has a first total suction surface area (A1) calculated by adding the suction surfaces of all the corresponding suction orifices (24). tot The first total suction surface area is greater than the second suction surface area (A2), i.e., A1 tot >A2.

8. The suction roller (1) according to one or more of the preceding claims, wherein at least one of the plurality of suction channels (23) is provided with a connecting portion (26), the connecting portion being configured to pneumatically connect the plurality of suction orifices (24) to an outlet orifice (25), the outlet orifice being located at the opposite end of the suction channel (23) relative to the plurality of suction orifices (24).

9. The suction roller (1) according to claim 8, wherein the connecting portion (26) has a cross-sectional passage (s) configured to decrease from the plurality of suction orifices (24) toward the outlet orifice (25).

10. The suction roller (1) according to any one of claims 7 to 9, wherein the total suction surface area (Atot) of the plurality of suction orifices (24) of the same suction channel (23) is greater than 35 mm. 2 .

11. The suction roller (1) according to any one of claims 7 to 9, wherein the total suction surface area (Atot) of the plurality of suction orifices (24) of the same suction channel (23) is greater than 80 mm. 2 .

12. The suction roller (1) according to any one of the preceding claims, wherein a plurality of insertion members (30) are provided, each insertion member being arranged to removably engage the rotating tubular body (20), each of the plurality of insertion members (30) including a body (31) having at least the plurality of suction orifices (24) arranged to connect to the same suction channel (23) in use.

13. The suction roller (1) according to claim 12, wherein each of the plurality of insertion members (30) further comprises at least one connecting portion (26) of the suction channel (23).

14. The suction roller (1) according to one or more of the preceding claims, wherein the means (50) for generating the airflow (55) pneumatically connected to the longitudinal suction chamber (16) is selected from: compressor; Centrifugal compressor; Fan; Centrifugal fan; Vacuum pump.

15. The suction roller (1) according to one or more of the preceding claims, wherein the suction distribution device (40) includes a fixed tubular body (10) coaxially mounted inside the rotating tubular body (20), the fixed tubular body (10) having a longitudinal suction chamber (16) pneumatically connected to the device (50) for generating a predetermined airflow, and having at least one row of circumferential orifices (15) arranged at predetermined angular positions of the rotating tubular body (20) to pneumatically connect the longitudinal suction chamber (16) to at least one row of the suction channels (23) each time.

16. The suction roller (1) according to any one of claims 1 to 14, wherein the suction distribution device (40) includes a first sealing element (18a) and a second sealing element (18b), the first sealing element (18a) and the second sealing element (18b) being integral with the fixed tubular body (10) from opposite sides relative to the or each row of circumferential orifices (15), the first sealing element (18a) and the second sealing element (18b) being longitudinally positioned relative to the fixed tubular body (10).

17. The suction roller (1) according to any one of claims 1 to 14, wherein the suction distribution device (40) comprises a plurality of sealing elements (17, 18) integral with and longitudinally positioned in relation to the rotating tubular body (20), each of the plurality of sealing elements (17, 18) being associated with at least one row of the suction channels arranged such that the outer surface (21) is pneumatically connected to the longitudinal suction chamber (16).

18. The suction roller (1) according to any one of claims 1 to 14, wherein the rotating tubular body (20) includes the longitudinal suction chamber (16), the longitudinal suction chamber being pneumatically connected to the suction distribution device (40) fixedly mounted at one end of the rotating tubular body (20).

19. The suction roller (1) according to any one of claims 8 to 14, wherein each of the plurality of insertion members is provided with a corresponding cover member (40), the cover member being provided with the plurality of suction orifices (24).

20. A paper processing machine comprising folding or staggering folding units arranged to fold or stagger sheet-like products according to a predetermined folding or staggering folding configuration, the sheet-like products being, in particular, webs or multiple sheets, characterized in that, The paper processing machine includes a first suction roller (1a) and a second suction roller (1b) according to any one of claims 1 to 19.

21. A paper processing machine, comprising a cutting unit configured to cut a continuous sheet-like product into a plurality of sheets, characterized in that, The paper processing machine includes at least one suction roller according to any one of claims 1 to 19.

22. A paper processing machine comprising a forwarding unit arranged to advance a sheet-like product along a predetermined forward direction, the sheet-like product being, in particular, paper webs or sheets, characterized in that, The paper processing machine includes at least one suction roller according to any one of claims 1 to 19.

23. The paper processing machine according to claims 2 and 20, wherein both the first suction roller (1a) and the second suction roller (1b) comprise: At least one first longitudinal row (3a''') is arranged to suck the head (6b) of a second sheet (5b) overlapping the first sheet (5a) in addition to sucking the middle portion (8a) of the first sheet (5a); and at least one second longitudinal row (3b''') is arranged to suck the tail (7c) of a third sheet (5c) overlapping the first sheet (5a) in addition to sucking the middle portion (8a) of the first sheet (5a). The paper processing machine is characterized in that the at least first longitudinal row (3a''') and / or the at least second longitudinal row (3b''') have a length greater than 1 mm per millimeter. 2 The average suction surface area.

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