Suction roller for sheet-shaped products

Abstract

A suction roller (1) for sheet-like products (5) comprises a fixed tubular body (10) having an outer side surface (11) and an inner side surface (12) communicating with each other through at least a first plurality of circumferential apertures (15a). The inside surface (12) defines a longitudinal suction chamber (16). Furthermore, a rotating tubular body (20) is provided, coaxially mounted with the fixed tubular body (10), having an outer side surface (21) and an inner side surface (22). The rotating tubular body (20) rotates about a longitudinal axis (120) and is provided with at least a first plurality of suction channels (23) arranged in a predetermined number of longitudinal rows (3). Rotation of the rotating tubular body (20) pneumatically connects the longitudinal suction chambers (16) in respective angular positions with at least one row (23) of suction channels (23). There is also a means (50) for generating an air flow, pneumatically connected to the longitudinal suction chamber (16) and selected from the group consisting of: a compressor, a centrifugal compressor, a fan, a centrifugal fan, such that the processed sheet-like products (5) are sucked at a time by at least one row of suction channels (23) and sucked to the outside surface (21) of the rotating tubular body (20) at the aforementioned different angular positions.

Description

Technical Field

[0001] This invention relates to the field of paper processing and similar products, and more particularly, to a suction roller (e.g., a forward roller, a cutting roller, a folding or staggered folding roller for a machine for staggered folding of paper webs or sheets), such a suction roller having suction holes connected to a vacuum system, allowing paper sheets or webs to adhere to the surface of the suction roller.

[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, the system is used to perform basic operations such as cutting paper, transferring paper very quickly from one roller to another, or performing a final fold on the paper itself.

[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 (typically 3 or 4 rows) of suction 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 device that generates a vacuum from the vacuum distribution device. More specifically, the holes of the rotating roller, positioned only between the two sealing elements at predetermined times, 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] However, these types of suction rollers have some drawbacks.

[0008] Specifically, paper processing machines typically have more than one suction roll, each guided to perform a defined operation in the production cycle. For example, folding or staggered folding machines generally have a cutting roll, one or more transfer rolls, and a pair of folding or staggered folding rolls. The different suction rolls of the machine are usually connected to the same vacuum generating device (e.g., a vacuum pump) via a series of pipes. Therefore, although pressure drops are inevitable along the suction lines, their dimensions must be designed to ensure a defined vacuum level within all suction rolls. Furthermore, these suction lines provide a series of valves for isolating or isolating the vacuum in different parts of the machine (especially the different suction rolls) to allow maintenance or replacement of each suction roll to be performed without disassembling the entire pipeline or adjusting the vacuum level to better suit the machine. This means a further concentrated pressure drop along the vacuum suction lines and a longer settling time required during the machine's start-up configuration phase.

[0009] In light of the above, it is necessary to increase the size of the device used to generate the vacuum to compensate for the aforementioned pressure drop and ensure the suction effect of different rollers. However, this implies high costs for the device and its operation, particularly due to the high power consumption of the vacuum generating device and the cost of the generator itself.

[0010] In addition to the above, during the operation of the suction roller, dust and material debris (especially paper debris) present in the environment surrounding the suction roller and generated during the working cycle are inevitably sucked up by the suction lines. Over time, this can lead to partial blockage of at least the suction orifices and the pipes connecting the vacuum generating device to different dispensing devices, thus causing a loss of effectiveness in the suction system, which inevitably results in a loss of quality in the final product. Therefore, known types of suction rollers must be regularly maintained and repaired to clean the different components that make up the suction roller. Maintenance and repair require the disassembly of all connections (usually flange connections) that hold the roller itself together. Then, several pipes, which can be tens of meters long, are disassembled to allow for cleaning, and after cleaning, these pipes are reconnected to each other and to each suction roller.

[0011] The same procedure is performed for routine maintenance and overhauls that involve replacing the sealing elements on a scheduled basis. In fact, the sealing elements will wear down over time due to friction generated as the rotating tubular body rotates around its longitudinal axis and due to the dragging of the sealing elements on the inner surface of the rotating tubular body.

[0012] Therefore, in view of the above, whether in the case of maintenance for cleaning several components of the suction roller or in the case of maintenance for replacing sealing elements, the maintenance and repair of the suction roller of the prior art is complex and extremely expensive in terms of manpower, cost and time.

[0013] Furthermore, a drawback of existing suction rollers is their inability to effectively control the adsorption of sheets or webs at high production speeds. These rollers have multiple rows of suction holes that must hold one or more layers of paper web on the outer surface of the rotating roller. The effective surface (the surface of the holes that apply the paper holding force) is very small, making it difficult to effectively control the holding, advancing, and releasing of the paper sheet or web.

[0014] Examples of known types of suction rollers with the aforementioned drawbacks are described in EP3724112 and US10294058. Summary of the Invention

[0015] Therefore, the object of the present invention is to provide a suction roller for a paper processing machine that overcomes the shortcomings of rollers in the prior art.

[0016] Specifically, one 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 repairs, particularly the replacement of the provided gaskets.

[0017] These and other objectives are achieved by a suction roller for suctioning sheet-like products to advance them in a forward direction, the suction roller comprising: A fixed tubular body having an outer surface and an inner surface defining a longitudinal suction chamber, the outer surface and the inner surface being arranged to communicate with each other through at least a first plurality of circumferential orifices distributed along a first longitudinal direction, each of the plurality of circumferential orifices being arranged along a corresponding circumferential portion of the fixed tubular body. A rotating tubular body, coaxially mounted to the fixed tubular body, has an outer surface and an inner surface, and is configured to rotate about a longitudinal axis of rotation outside the fixed tubular body. The rotating tubular body is provided with at least a first plurality of suction channels arranged in a corresponding predetermined number of longitudinal rows. The rotation of the rotating tubular body about the longitudinal axis of rotation is adapted to dynamically connect the longitudinal suction chamber to at least one row of the first plurality of suction channels at a corresponding predetermined angular position of the rotating tubular body. A device for generating an airflow is configured such that the sheet-like product being processed is drawn in by at least one row of the suction channels each time and adsorbed onto the outer surface of the rotating tubular body at a predetermined angular position. The main feature of the suction roller is that the device for generating airflow is selected from: a compressor, a centrifugal compressor, a fan, a centrifugal blower, and is pneumatically connected to the longitudinal suction chamber.

[0018] Other features and related embodiments of the invention are set forth in the dependent claims.

[0019] Specifically, the rotating tubular body may also have at least a second or more suction channels arranged in a predetermined number of longitudinal rows.

[0020] Specifically, the fixed tubular body may also be provided with a second plurality of circumferential orifices positioned along the second direction of the fixed tubular body in the longitudinal direction.

[0021] 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.

[0022] 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 to generate an airflow within a longitudinal suction chamber. In an advantageous embodiment, the aforementioned device for generating an airflow is configured to generate an airflow at a predetermined pressure (Pi) below atmospheric pressure.

[0023] Specifically, the rotating tubular body may also be provided with at least a third plurality of suction channels arranged in a predetermined number of longitudinal rows. More specifically, the longitudinal rows or each longitudinal row of the first plurality of suction channels and the second plurality of suction channels 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 longitudinal row of the third plurality of suction channels 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.

[0024] In one embodiment of the present invention, the first plurality of suction channels and the second plurality of suction channels may be arranged in multiple suction groups on multiple rows circumferentially to the rotating tubular body.

[0025] Specifically, each of the aforementioned plurality of suction groups may include at least one first suction channel among a plurality of first suction channels separated by a partition wall and at least one second suction channel among a plurality of second suction channels.

[0026] Specifically, the suction channels can be configured such that the cross-section passage of each of the aforementioned first plurality of suction channels and second plurality of suction channels is adapted to increase from the inner surface of the rotating tubular body toward the outer surface for at least a portion of its length.

[0027] Similarly, the cross-sectional passage of each of the aforementioned third plurality of suction channels can increase from the inner surface of the rotating tubular body toward the outer surface.

[0028] Specifically, the first and second longitudinal rows of the fixed tubular body have first and second plurality of circumferential orifices having corresponding circumferential portions arranged side by side or at least partially side by side along the longitudinal direction.

[0029] According to another aspect of the invention, a suction roller for a sheet-like product is configured to advance the sheet-like product along a forward direction, the suction roller comprising: A fixed tubular body has an outer surface and an inner surface defining a longitudinal suction chamber. The outer surface and the inner surface are arranged to communicate through a first plurality of circumferential orifices arranged along a first longitudinal direction. Each of the plurality of circumferential orifices is arranged along a corresponding circumferential portion of the fixed tubular body. A rotating tubular body, coaxially mounted to the fixed tubular body, has an outer surface and an inner surface, and is configured to rotate about a longitudinal axis of rotation outside the fixed tubular body. The rotating tubular body is provided with at least a first plurality of suction channels arranged in a predetermined number of longitudinal rows. The rotation of the rotating tubular body about the longitudinal axis of rotation is adapted to dynamically connect the longitudinal suction chamber to at least one row of the first plurality of suction channels at a corresponding predetermined angular position of the rotating tubular body at a time. A device for generating an airflow is configured to generate an airflow at a defined pressure within the longitudinal suction chamber, such that the processed sheet-like product is drawn in and adsorbed onto the outer surface of the rotating tubular body at a predetermined angular position. The fixed tubular body is further provided with a second plurality of circumferential orifices distributed along a corresponding second longitudinal direction. Each of the first plurality of circumferential orifices and the second plurality of circumferential orifices is arranged along a corresponding circumferential portion of the fixed tubular body to dynamically connect the longitudinal suction chamber to at least one of the first plurality of suction channels at a predetermined angular position of the rotating tubular body.

[0030] 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 adapted to fold or stagger webs or multiple sheets made of sheet material (especially paper) according to a predetermined folding or staggered folding configuration; The cutting unit is configured to cut a continuous web made of sheet material into multiple sheets of predetermined length; The forward unit is arranged to advance the paper web or sheet along a predetermined forward direction; Or a combination of the above units; The processing unit or each processing unit includes at least one suction roller as described above. Attached Figure Description

[0031] The invention will now be described with reference to the accompanying drawings, by way of 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 fixed tubular body of the suction roller according to the present invention is shown schematically. Figure 2 A perspective side view of a first embodiment of the suction roller according to the present invention is shown schematically; Figure 3 schematically shown Figure 2 The longitudinal section of the suction roller; Figure 4schematically shown Figure 2 The transverse cross-section of the suction roller; Figure 5 schematically shows Figure 2 The longitudinal section of an alternative embodiment of the suction roller; Figure 6 An enlarged view of a portion of Figure 5 is shown schematically to highlight some technical features; Figure 7 The alternative is shown schematically. Figure 1 A perspective side view of an embodiment of a fixed tubular body; Figure 8 and Figure 9 schematically shown Figure 2 A perspective side view of two possible alternative embodiments of the suction roller; Figure 10 It shows Figure 9 A magnified view of a portion to highlight certain technical features; Figure 11 Another alternative embodiment of the suction roller according to the invention is shown; Figure 12 The illustration schematically shows a possible embodiment of a suction assembly that can be used with the suction rollers according to the invention in an engaged configuration; Figure 13 The image shown is cut off according to arrow XIII-XIII. Figure 12 Cross-sectional view of the suction assembly; Figure 14 The schematic diagram shows the state of being out of configuration. Figure 12 The suction unit; Figure 15 An auxiliary suction assembly that can be used by the suction roller according to the invention is schematically shown; Figure 16 and Figure 17 schematically shown Figure 11 Two different transverse sections of the suction roller; Figures 18 to 20 A side perspective view schematically illustrates another embodiment of the suction roller according to the invention; Figure 21 A perspective side view of a fixed tubular body according to another embodiment of the present invention is shown schematically. Detailed Implementation

[0032] like Figure 1 The suction roller 1 according to the invention, schematically shown, is of the type used, particularly in paper processing machines or similar products, to feed sheet-like products (e.g., paper webs or sheets) along a forward direction. The suction roller 1 includes a fixed tubular body 10, which has an outer surface 11 and an inner surface 12 defining a longitudinal suction chamber 16. More specifically, according to... Figure 1 The first embodiment of the invention, schematically shown in the figure, has a fixed tubular body 10 provided with a first plurality of circumferential openings 15a, which are positioned along a first longitudinal direction 13 and adapted to pneumatically connect the outer surface 11 to the inner surface 12.

[0033] Furthermore, the suction roller 1 is provided with a rotating tubular body 20, which is coaxially mounted to the fixed tubular body 10 and configured to rotate about a longitudinal rotation axis 120 outside the fixed tubular body. The rotating tubular body 20 has an outer surface 21 and an inner surface 22. Specifically, an element that allows rotation relative to each other can be provided between the rotating tubular body 20 and the fixed tubular body 10, such as... Figure 3 The four bearings 85 shown are schematically arranged, or brass (copper alloy bearing bushes, copper sleeves), or other similar devices.

[0034] More specifically, the rotating tubular body 20 is provided with at least a first plurality of suction channels 23 arranged in a predetermined number of longitudinal rows 3.

[0035] In an alternative embodiment of the invention, a second plurality of suction channels 24 are also provided in a corresponding number of longitudinally arranged rows 4.

[0036] exist Figures 2 to 4 In the schematically illustrated embodiment, the rotating tubular body 20 is provided with five rows of such first plurality of suction channels 23, 3a-3e. Figure 2 The image shows the first two rows 3a and 3b, and the second multiple suction channels 24 in the fifth row 4a-4e, where... Figure 2 The first two rows, 4a and 4b, are shown. The number of rows 3a and 3b of the rotating tubular body 20 can be varied depending on the production and functional requirements of the machine using the suction roller 1.

[0037] It also includes a device 50 for generating an airflow, which is arranged to generate an airflow at a predetermined pressure (particularly less than atmospheric pressure) within the longitudinal suction chamber 16.

[0038] Specifically, the device 50 for generating airflow is configured to move the airflow between the inlet 16a and the outlet 16b through the longitudinal suction chamber 16 provided by the fixed tubular body 10. In this way, as the rotating tubular body 20 rotates 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.

[0039] like Figure 18 or Figure 19As schematically shown, the device 50 for generating the airflow can be a device suitable for generating an airflow at a predetermined vacuum level (e.g., a vacuum pump). In an alternative embodiment according to the invention and schematically shown in FIG. 5, the device 50 for generating the airflow can be arranged to generate a pressure jump in the airflow 55 between the suction zone and the pump zone. This device is, for example, a compressor, centrifugal compressor, axial compressor, rotary compressor, or fan, particularly a centrifugal fan, or axial fan, or other known types. In this case, the device 50 is advantageously connected at the suction point to the longitudinal suction chamber 16 to generate a pressure less than atmospheric pressure within the longitudinal suction chamber 16, while a higher pressure is generated 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. Specifically, each of the first plurality of circumferential apertures (or curved apertures) 15a is arranged along a corresponding circumferential portion of the fixed tubular body 10 so that when the rotating tubular body 20 reaches the aforementioned predetermined angular position during rotation about the rotation axis 120, the longitudinal suction chamber 16 is pneumatically connected to at least one row 3a-3e or 4a-4e of the first and second plurality of suction channels 23, 24, respectively. In the suction roller 1, the head or a portion of the sheet can be adsorbed onto the rows 4a-4e of the second plurality of suction channels 24, and the tail of the sheet can be adsorbed onto the rows 3a-3e of the first plurality of suction channels 23. In prior art folding rollers and / or forward rollers, it is known to use holes on the outer surface of the rotating tubular body to suction, hold, and move webs or sheets. Suction is achieved by a vacuum pump, therefore, the diameter of the holes is small in order not to lose too much suction capacity. Typically, the plurality of holes are aligned with each other along a row. Depending on the desired outcome, each row has a predetermined number of holes, meaning each row corresponds to a precise portion of the sheet to be processed. For example, one row of holes may be used to hold the starting edge or head of the sheet, another row to hold the ending edge or tail, and yet another row to hold the center portion of the sheet. In some cases, the center 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 diameters of the holes themselves in different rows may differ. The total number of holes in each row depends on the dimensions of the processing line, that is, on the length of the rotating tubular body 20. Each suction hole on the outer surface of the rotating tubular body 20 corresponds to a suction channel that pneumatically connects the outer surface of the rotating tubular body 20 to its inner surface. These channels are typically straight because they are formed by mechanically drilling the rotating tubular body 20.In other cases (as described in EP3724112), multiple groups or blocks can be configured with multiple sets of suction holes screwed onto a rotating tubular body so that the outer surface of the block coincides with the outer surface of the rotating tubular body. Similarly, in this case, multiple rows of holes are obtained, each row used to hold a specific portion of the sheet. For example, in EP3724112, 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 completely equivalent to the multiple rows of holes formed directly into the rotating tubular body. Typically, in the case of holes obtained by directly penetrating the rotating tubular body and in the case of holes provided on the block as described above, the distribution of the multiple holes in each row in the longitudinal direction can be non-uniform.

[0040] Apart from the mechanical operation involving the presence or absence of countersunk holes, all of the aforementioned holes have a substantially constant cross-sectional area.

[0041] In EP3724112, each set of holes has at most two rows of suction holes; for example, one row of holes is used to suction the head of the sheet, and the other row is used to suction the tail of the sheet. In other cases, one or two rows of holes can be used to suction the center portion of the sheet.

[0042] In existing suction rollers, the effective surface (i.e., the suction surface in contact with the sheet) is formed by the area of ​​the holes and other areas that may exist. For example, the holes can have a maximum diameter of approximately 3.5 mm and countersunk holes of 1.25 mm, resulting in an effective circular suction surface with a diameter of up to 6 mm on the outer surface of the suction roller. The diameter of the holes can vary depending on the paper, the paper's basis weight, the production speed of the machine design, and many other factors. For example, the diameter of each hole can vary between approximately 2 mm and 3.5 mm, and the countersunk holes can vary between 0.5 mm and 1.25 mm. Typically, on the outer surface of the rotating tubular body, considering any countersunk hole operation, the opening corresponding to each hole is approximately 7 mm. 2 Up to 30mm 2 between.

[0043] Furthermore, in this multi-group hole configuration, each row of holes can be formed by a different number of holes. For example, a general-purpose forward roller for sheet material can have multiple groups of holes aligned with each other, which are formed by a row of three holes with a diameter of 3.5 mm for holding the head of the sheet and a row of single holes with a diameter of 3.5 mm for holding the tail of the sheet.

[0044] In the prior art, for a suction roller with an outer surface of approximately 2750 mm, each row of suction holes is formed by multiple sets of three suction holes aligned to each other, each with a diameter of 6 mm (including countersunk holes), and the number of sets of three holes is 45. Calculated by multiplying the area of ​​each hole by the number of holes in that row, the total suction surface is approximately 3815 mm. 2 Therefore, in existing rollers, on average, for every millimeter of the outer surface length of the suction roller, the suction surface has approximately 1.4 mm. 2 The maximum value of / mm is obtained by dividing the total suction roller (suction surface) by the length of the outer surface of the suction roller.

[0045] According to the present invention, each of the first plurality of suction channels 23 and the second plurality of suction channels 24 is associated with a suction area at the outer surface 21 of the rotating tubular body 20, the suction area being greater than or equal to 1.5 mm. 2 / mm (i.e., the length per millimeter of the outer surface 21 of the rotating tubular body 20). Suction channels 23 and 24 can be arranged on multiple suction groups 30. Preferably, the suction groups 30 are arranged longitudinally side-by-side in a direction parallel to the first longitudinal direction 13, forming a linear suction surface corresponding to a row of holes in the prior art. In other words, each suction channel 23, 24 can be used to hold a predetermined portion of the sheet. For example, multiple aligned suction channels 23 can hold the tail of the sheet, while a row of aligned suction channels 24 can hold the starting edge of the sheet. Suction channels 23, 24 can be defined by rectangular surfaces. In this case, without considering any bevels or angular fittings, the height and length of the suction channels 23, 24 result in a ratio of the total length of the suction roller (suction surface) to the length of the outer surface 21 greater than 1.5 mm. 2 / mm. The total suction roller (suction surface) is equal to the sum of the orifices of each suction group arranged along the first longitudinal direction 13. In some embodiments, the length of the suction group 30 and / or the dimensions of the side surfaces of the suction surface or the shape of the suction channels 23, 24 can be changed to keep the size of the smaller suction channel equal to 1.5 mm. 2 / mm (i.e., the length per millimeter of the outer surface of the rotating tubular body 20).

[0046] In this way, effective suction of sheet-like products is achieved through suction channels 23 and 24. Increasing the effective surface area of ​​the outer surface 21 of the rotating tubular body 20 (i.e., increasing the portion of the outer surface 21 suitable for holding the paper) allows the sheet or web to be more uniformly adsorbed onto the outer surface 21 of the rotating tubular body 20, resulting in stronger and more stable adsorption compared to prior art suction rollers. In this case, any type of suction can be used; that is, a vacuum pump, centrifugal compressor, axial or radial fan, or any other device suitable for generating airflow within the longitudinal suction chamber 16 can be used, particularly at pressures less than atmospheric pressure outside the rotating tubular body 20, advantageously less than 0.9 atm, for example less than 0.8 atm.

[0047] like Figure 1 As shown, the circumferential portion of the outer surface 11 of the fixed tubular body 10, which is provided with circumferential orifices 15a, is located between two identical generatrixes 101 and 102 of the fixed tubular body 10.

[0048] In contrast, such as Figure 7 As schematically illustrated, in a predetermined alternative embodiment, 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 a first longitudinal direction 13 and a second longitudinal direction 14. Specifically, in Figure 7 In one embodiment, the circumferential portions with circumferential openings 15a and 15b are pre-set to be circumferentially staggered relative to each other. More specifically, as... Figure 5 and Figure 11 As shown, the circumferential portions with circumferential openings 15a and 15b can partially overlap each other. In other words, the first plurality of circumferential openings 15a and the second plurality of circumferential openings 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 or substantially side-by-side and extending circumferentially in the longitudinal direction. More specifically, the aforementioned circumferential openings 15a and 15b can have corresponding circumferential portions 17a and 17b arranged side-by-side in the longitudinal direction, i.e., as shown in the figure. Figure 7 As schematically shown, circumferential portions 17a and circumferential portions 17b meet along a predetermined generatrix of the cylindrical body. More specifically, each of the first plurality of circumferential orifices (or arcuate orifices) 15a can be positioned close to a corresponding circumferential orifice (or arcuate orifice) 15b in the second plurality of circumferential orifices, for example, at a distance between 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.

[0049] For example, Figure 21As schematically shown, the device 50 for generating airflow may include a body 51 on 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.

[0050] The device 50 for generating airflow can be pneumatically connected to the aforementioned longitudinal suction chamber 16 via at least one conduit 60, or it can be integrally mounted to the fixed tubular body 10 (see...). Figure 19 In both cases, the device 50 for generating the airflow is arranged to generate a defined airflow 55 within the longitudinal suction chamber 16 at a predetermined pressure (Pi) (preferably, a pressure less than atmospheric pressure).

[0051] For example in Figure 8 As schematically shown in the embodiments, the rotating tubular body 20 may also be provided with at least a third plurality of suction channels 25 arranged in a predetermined number of longitudinal rows. Specifically, the aforementioned third plurality of suction channels 25 can be used to fold sheets or webs of sheet-like materials, such as paper or cardboard, or nonwoven fabrics and similar materials. For example, as in Figure 16 The embodiments are shown schematically, but as a reference, those skilled in the art will readily understand that, and it is also effective for the embodiments of the present invention, the first plurality of suction channels 23 and the second plurality of suction channels 24 can be used respectively to suction at least one sheet of sheet material 5 at a time from the head 6 and tail 7, and in particular to convey it downstream of the cutting section (not shown in the figure for simplicity).

[0052] In a pre-defined embodiment, the first plurality of suction channels and the longitudinal rows or suction channels 23 and 24 of the second plurality of suction channels can be positioned on the rotating tubular body 20 and pneumatically connected to the first plurality of circumferential orifices 15a at the aforementioned corresponding predetermined angular positions. Conversely, the longitudinal rows or suction channels 25 of the third plurality of suction channels can be positioned on the rotating tubular body 20 and pneumatically connected to the second plurality of circumferential orifices 15b at the corresponding predetermined angular positions. For example, as described above, the first plurality of suction channels 23 and the second plurality of suction channels 24 can be adapted to suction the head or part of the head and the tail or part of the tail of a sheet of sheet material (especially paper) onto the surface 21 of the rotating tubular body 20, and the third plurality of suction channels 25 can be adapted to suction the sheet at the central portion of the sheet, particularly allowing the suction roller 1 to cooperate with the second suction roller 1 rotating in the opposite direction to it to perform folding or staggered folding at folding or staggered folding points.

[0053] In embodiments according to the present invention, such as Figures 12 to 17As shown, the first plurality of suction channels 23 and the second plurality of suction channels 24 can be arranged in the form of a plurality of suction groups 30. These suction groups can be arranged circumferentially on multiple rows 36 of the rotating tubular body 20. Specifically, each suction group 30 includes a first suction channel 23 of the first plurality of suction channels and a second suction channel 24 of the second plurality of suction channels separated by a partition wall 27.

[0054] In another embodiment, a fourth plurality of suction channels 26 are also provided, arranged longitudinally along at least one row of the rotating tubular body 20.

[0055] In the presence of the aforementioned fourth or more suction channels 26, a second or more suction groups 30' can also be provided. Specifically, for example... Figure 19 As shown, each of the second plurality of suction groups 30' may include at least one suction channel 25 of a third plurality of suction channels and at least one suction channel 26 of a fourth plurality of suction channels separated from each other by partition walls 27'. Suction channel 26 may also participate in the suction step of the central portion 8 of sheet 5.

[0056] Specifically, the longitudinal rows of the first suction group 30 and the second suction group 30' can preferably be alternately positioned on the rotating tubular body 20.

[0057] As schematically shown in Figure 23, at least one pressure sensor 80 may also be provided, arranged to detect the pressure within the longitudinal suction chamber 16. Specifically, this pressure sensor, or each pressure sensor 80, may be arranged to send a corresponding pressure signal P(ti) to a control unit 300, which is arranged to operate the aforementioned device 50 for generating airflow. More specifically, the control unit 300 may be arranged to adjust the device 50 for generating airflow based on the received pressure signal P(ti), and particularly by acting on a motor 56 provided for this purpose. In this way, the airflow 55 can be increased or decreased to increase or decrease the pressure P(ti) within the longitudinal suction chamber 16, making it equal to a predetermined pressure value P. Or, in any way, make it related to pressure P The difference is less than the predetermined deviation value ΔP That is, ׀P(ti)-P ׀≤ΔP .

[0058] For example, such as Figure 3 , Figure 4 , Figure 6 and Figures 13 to 15As shown, as the rotating tubular body 20 moves from its inner surface 22 to its outer surface 21, the cross-sectional passage of each of the first plurality of suction channels 23 and / or the second plurality of suction channels 24 can be increased at least a portion of its respective length. Advantageously, each of the first plurality of suction channels 23 and 24, and each of the third plurality of suction channels 25 and 26 (if present), and the fourth plurality of suction channels, is associated with a corresponding protective member 40. Specifically, this may be provided with a plurality of orifices 41, the size of which prevents the processed sheet material (particularly paper webs or sheets) from entering the suction channels 23, 24, and similarly into the suction channels 25 and 26 (if present), while simultaneously allowing the product to be drawn in at predetermined angular portions of the outer surface 21 of the rotating tubular body 20 at circumferential orifices 15a and 15b, so that it is transferred downstream of the suction roller 1 along the aforementioned direction of travel.

[0059] Specifically, such as Figures 16 to 19 As schematically shown, each suction assembly 30 may include a hollow body 31, which is provided with a first suction channel 23 and a second suction channel 24. Figures 16 to 18 ), or the third suction channel 25 and the fourth suction channel 26 ( Figure 19 ).

[0060] Specifically, each suction assembly 30 can be associated with a corresponding protective member 40, which advantageously has a plurality of holes 41. The protective member 40 can be configured from an engaging configuration ( Figure 16 and Figure 17 Move to disengagement configuration ( Figure 18 and Figure 19 For example, through a connector that can be disassembled by screws, bolts, or similar connecting elements (not shown in the figures for simplicity). In this way, the protective member 40 can be removed when needed, or during planned maintenance of routine maintenance, to make access to the hollow body 31 and thus perform cleaning maintenance of the suction channels 23, 24, 25, and 26 for cleaning dust or debris of the processed product from the suction channels during machine operation equipped with the suction roller 1 or each suction roller 1 according to the invention, during which dust or said debris inevitably enters the suction channels. In addition, the protective member 40 can be replaced with another different type of protective member 40 (e.g., with a different number of holes 41, or generally with a different total suction area to change the airflow through the protective member 40 itself). Specifically, in use, each hollow body 31 is accommodated in a corresponding seat 28 provided on the rotating tubular body 20.

[0061] More specifically, the protective member 40 is provided with the aforementioned plurality of holes 41. These are adapted to pneumatically connect each suction channel 23, 24, 25 and 26 to the outer surface 21 of the rotating tubular body 20. Advantageously, the inlet openings 23a, 24a, 25a and 26a of the suction channels are smaller than the outlet openings 23b, 24b, 25b and 26b.

[0062] like Figure 18 In the embodiment shown schematically, the protective member 40 may have a longitudinal lower portion 45. In this way, under working conditions, it is possible to avoid obstructing the movement of the cutting blade (if present, but not shown in the figure for simplicity), which is located downstream of the suction roller 1, to cut a continuous web made of sheet material into multiple sheets of predetermined lengths.

[0063] like Figures 1 to 2 As schematically shown in Figure 5, each suction channel 23, 24, 25 and 26 is configured to extend longitudinally into the rotating tubular body 20.

[0064] Similarly, each circumferential orifice 15a and 15b can be configured to extend longitudinally into the fixed tubular body 10.

[0065] In the embodiment schematically shown in Figure 24, a cover member 70 is provided, adapted to be positioned at the inlet 16a of the longitudinal suction chamber 16. Specifically, the cover member 70 may have a passage opening 71 through which airflow 55 enters the longitudinal chamber 16 being suctioned by the device 50 for generating airflow, and may also include an adjustment assembly 77 to increase or decrease the cross-sectional area of ​​the passage opening 71. For example, as shown in Figure 24, the adjustment assembly 77 may include a series of movable elements 75 adapted to engage in corresponding guides 76 for guided movement, and to increase or decrease the cross-section of the passage opening 71 as needed.

[0066] In another embodiment schematically shown in FIG25, the fixed tubular body 10 may advantageously be provided with an annular portion 18 between the circumferential orifice 15a (or 15b) and the immediately following circumferential orifice 15a (or 15b), the annular portion 18 being adapted to pneumatically separate the two.

[0067] The suction roller 1 described above can be installed in the processing unit of a paper processing machine.

[0068] Specifically, at least the first and second counter-rotating suction rollers 1 can be installed at a folding or staggering folding unit configured to fold or stagger webs or multiple sheets according to a predetermined folding or staggering folding configuration.

[0069] As described above, the suction roller 1 can also be installed at the cutting unit, which is configured to cut a continuous web made of sheet material into multiple sheets so that they move downstream of the aforementioned cutting unit.

[0070] In a predetermined embodiment, as described above, the suction roller 1 can be mounted on a forward unit configured to advance the paper web or sheet along a predetermined forward direction.

[0071] 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 record the start and end of suction in suction channels 23, 24, and 25 (if present). The angle adjustment of the fixed tubular body 10 can be performed by an actuator connected to one end of the fixed tubular body 10. This adjustment can be performed via commands given through an HMI (Human Machine Interface) during both the testing phase and the operating phase of the staggered folding machine.

[0072] Optionally, the control unit can be programmed to automatically change the angular position of the fixed tubular body 10 according to 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. Therefore, the angular change in the timing of the 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 according to a speed threshold, i.e., for each predetermined increase or decrease in the sheet feed speed, the fixed tubular body 10 rotates clockwise or counterclockwise at a desired angle. For example, the angular position of the fixed tubular body 10 can be changed for every 50 m / min increase or decrease in the sheet feed speed. The rotation amount and speed increments of the fixed tubular body 10 can be changed according to the product and / or the product supply 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, changing the angular position of the fixed tubular body 10 once the predetermined sheet feed speed is reached.

[0073] 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 to advance the sheet-like product along a forward direction, the suction roller (1) comprising: A fixed tubular body (10) is provided with an outer surface (11) and an inner surface (12) defining a longitudinal suction chamber (16), the outer surface (11) and the inner surface (12) being arranged to communicate through at least a first plurality of circumferential orifices (15a) distributed along a first longitudinal row (13), each of the plurality of circumferential orifices (15a) being arranged along a corresponding circumferential portion of the fixed tubular body (10); A rotating tubular body (20), coaxially mounted to the fixed tubular body (10), has an outer surface (21) and an inner surface (22), and is configured to rotate about a longitudinal axis of rotation (120) outside the fixed tubular body (10). The rotating tubular body (20) is provided with at least a first plurality of suction channels (23) arranged in a predetermined number of longitudinal rows (3). The rotation of the rotating tubular body (20) about the longitudinal axis of rotation (120) is adapted to pneumatically connect the longitudinal suction chamber (16) to at least one row (23) of the first plurality of suction channels (23) at a corresponding predetermined angular position of the rotating tubular body (20). The device (50) for generating airflow is configured such that the sheet-like product (5) being processed is drawn by at least one row of the suction channel (23) each time and adsorbed onto the outer surface (21) of the rotating tubular body (20) at the predetermined angular position. The suction roller (1) is characterized in that the device (50) for generating airflow is pneumatically connected to the longitudinal suction chamber (16) and is selected from: a compressor, a centrifugal compressor, a fan, and a centrifugal fan.

2. The suction roller (1) according to claim 1, wherein the means (50) for generating the airflow is configured to generate the airflow at a predetermined pressure (Pi), and includes: Main body (51); An impeller (52), adapted to be housed in the body (51) and operatively connected to a motor (56) to rotate about a rotation axis, for generating a defined airflow in the longitudinal suction chamber (16).

3. The suction roller (1) according to claim 1, wherein the main body (51) is integral with the fixed tubular body (10).

4. The suction roller (1) according to claim 2 or 3, wherein the predetermined pressure (Pi) is less than atmospheric pressure.

5. The suction roller (1) according to one or more of the preceding claims, wherein the rotating tubular body (20) is further provided with at least a second plurality of suction channels (24) arranged in a corresponding predetermined number of longitudinal rows (4).

6. The suction roller (1) according to one or more of the preceding claims, wherein the fixed tubular body (10) is further provided with a second plurality of circumferential orifices (15b) positioned along the second longitudinal row (14), the first plurality of circumferential orifices (15a) and the second plurality of circumferential orifices (15b) being circumferentially intersecting each other.

7. The suction roller (1) according to claim 6, wherein each of the first plurality of circumferential orifices or arcuate orifices (15a) is located at a distance between 1 mm and 150 mm from the corresponding circumferential orifice or arcuate orifice (15b) in the second plurality of circumferential orifices.

8. The suction roller (1) according to any one of claims 5 to 7, wherein the rotating tubular body (20) is further provided with at least a third plurality of suction channels (25) arranged in a corresponding predetermined number of longitudinal rows (5), wherein the first plurality of suction channels (23) and each longitudinal row (3, 4) of the second plurality of suction channels (24) are positioned on the rotating tubular body (20) to be pneumatically connected to the first plurality of circumferential orifices at the corresponding angular positions, and the third plurality of suction channels (25) are positioned on the rotating tubular body (20) to be pneumatically connected to the second plurality of circumferential orifices (15b) at the corresponding predetermined angular positions.

9. The suction roller (1) according to one or more of the preceding claims, wherein the first plurality of suction channels (23) and the second plurality of suction channels (24) are arranged in a plurality of suction groups (30), the plurality of suction groups being arranged on a plurality of longitudinal rows (36) of the rotating tubular body (20), each of the plurality of suction groups (30) comprising a first suction channel (23) of the first plurality of suction channels and a second suction channel (24) of the second plurality of suction channels separated by a partition wall (27).

10. The suction roller (1) according to one or more of the preceding claims, wherein at least one pressure sensor (80) is provided, the at least one pressure sensor being arranged to detect the pressure in the longitudinal suction chamber (16) and send a corresponding pressure signal (P(ti)) to a control unit (300), the control unit being arranged to control the means (50) for generating airflow according to the pressure signal (P(ti)).

11. The suction roller (1) according to one or more of the preceding claims, wherein the suction channels (23) are configured such that the channel cross section of each of the first plurality of suction channels (23) is adapted to increase from the inner surface (22) to the outer surface (21) of the rotating tubular body (20).

12. The suction roller (1) according to claim 6 or 7, wherein the first plurality of circumferential orifices (15a) and the second plurality of circumferential orifices (15b) of the first longitudinal row (13) and the second longitudinal row (14) of the fixed tubular body (10) have corresponding circumferential portions (17a, 17b) arranged side by side in the longitudinal direction.

13. The suction roller (1) according to any one of claims 9 to 12, wherein each of the plurality of suction groups (30) is associated with a corresponding protective member (40) having a plurality of holes (41) sized to prevent the processed sheet product from entering the suction channels (23, 24) of the first plurality of suction channels and the second plurality of suction channels, and simultaneously allowing the processed sheet product to be suctioned to adsorb onto the predetermined angle portion of the outer surface (21) of the rotating tubular body (20).

14. The suction roller (1) according to one or more of the preceding claims, further comprising a cover member (70) adapted to be positioned at the inlet (16a) of the longitudinal suction chamber (16), the cover member (70) having a passage opening (71) through which the airflow is adapted to enter the longitudinal chamber (16) being drawn by the means (50) for generating the airflow, and wherein, It also includes an adjustment group (77) suitable for increasing or decreasing the cross-sectional passage opening of the passage.

15. The suction roller (1) according to claim 10, wherein the control unit (300) is configured to act on the motor (56) to increase or decrease the airflow (55) according to the pressure signal (P(ti)), thereby making the pressure signal (P(ti)) equal to a predetermined pressure value (P). ), or the difference between the pressure value and the predetermined pressure value is less than the predetermined deviation value (ΔP). ).

16. The suction roller (1) according to claim 5, wherein the first plurality of suction channels (23) are arranged to suction the head portion of the sheet onto the surface (21) of the rotating tubular body (20), and the second plurality of suction channels (24) are arranged to suction the tail portion of the sheet onto the surface (21) of the rotating tubular body (20).

17. The suction roller (1) according to claims 8 and 16, wherein the third plurality of suction channels (25) are arranged to suction the central portion of the sheet onto the surface (21) of the rotating tubular body (20), thereby performing folding on the processed sheet.

18. The suction roller (1) according to claim 13, wherein the protective member (40) is provided with a longitudinal lower portion (45) so as not to obstruct the movement of the cutting blade located upstream of the suction roller (1).

19. A paper processing machine, comprising at least one processing unit, said processing unit being selected from: Folding or staggered folding units are arranged to fold or stagger sheet-like products according to a predetermined folding or staggered folding configuration; The cutting unit is configured to cut a continuous web made of sheet material into multiple sheets; The forward unit is arranged to move the sheet-like product along a predetermined forward direction; Or a combination of the above units; The paper processing machine is characterized in that the at least one processing unit includes at least one suction roller according to any one of claims 1 to 18.

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