METHOD, PLANT AND STRUCTURE OF BLADE FOR CUTTING LOGS OF PAPER AND SIMILAR MATERIAL

Abstract

A method, a plant and a blade for cutting logs that provide a cutting region crossed by at least one log according to a conveying direction transversal to a cutting plane, and a blade having a longitudinal axis. The blade comprises a plane cutting portion and a connection portion connected thereto. The cutting portion has a cross section of minimum width, a cross section of maximum width and at least one cutting profile that extends obliquely between the cross section of minimum width and the cross section of maximum width, so that the cutting profile forms an angle with respect to the longitudinal axis. The cutting profile has a cutting height in a direction orthogonal to the longitudinal axis equal to at least the difference between the cross sections of maximum width and of minimum width. The connection portion has width less than or equal to the minimum width.

Claims

1. A method for cutting logs comprising the steps of: prearranging at least one cutting region configured to be crossed by at least one log according to a conveying direction transversal to a cutting plane; prearranging a blade having a longitudinal axis and comprising: a plane cutting portion and a connection portion connected to said cutting portion; and said cutting portion having a cross section of minimum width, a cross section of maximum width and at least one cutting profile that extends obliquely between said cross section of minimum width, and said cross section of maximum width so that said cutting profile forms an angle with respect to said longitudinal axis set between 1° and 60°, in particular between 1° and 30°, much more in particular, between 1° and 10°, preferably between 1° and 8°, said cutting profile having a cutting height in a direction that is orthogonal to said longitudinal axis equal to at least the difference between said cross section of maximum width and said cross section of minimum width, and said connection portion having width less than or equal to said minimum width moving said blade parallel to said longitudinal axis so that said connection portion and said cutting portion cross in turn said cutting region and said cutting portion passes through said cutting region according to said cutting plane; and conveying said or each logs on a respective cutting cradle in said cutting region, said or each logs having a height less than said cutting height so that said cutting profile that extends obliquely cuts said logs during said movement starting from a point in which it comes in contact with said log, causing a cut in said logs and obtaining cut portions having a same length as a predetermined conveying length.

2. The method according to claim 1, wherein said blade is selected from the group consisting of: a blade with said cutting portion having a single cutting profile, a blade with said cutting portion having two cutting profiles opposite to each other with respect to said longitudinal axis, in said cutting region logs being fed opposite to each other with respect to said longitudinal axis so that respective logs are cut by respective cutting profiles; a blade with said cutting portion having two cutting profiles arranged at a same side with respect to said longitudinal axis, said two cutting profiles cutting said logs when said blade is moved according to an alternated movement in respective opposite directions; and a combination thereof.

3. The method according to claim 1, wherein said blade is selected from the group consisting of: a blade in which said plane cutting portion and said connection portion connected to said cutting portion are consisting of a single plane band, selected from the group consisting of: a band continuously looped about at least two flywheels that provide a continuous movement, a reciprocating band; and a blade in which said plane cutting portion comprises a plane band and said connection portion is a connecting element connected to said plane cutting portion, and wherein said blade is selected from the group consisting of: a continuous blade looped around about at least two flywheels that provide a continuous movement, a discontinuous blade having reciprocating movement, and wherein said connection portion is selected from the group consisting of: a band portion, a chain portion, a rope portion, a belt portion.

4. The method according to claim 1, wherein said blade comprises a conveying portion having a larger width than said cutting portion, said conveying portion OM-defining at least one elongated hole on which said at least one cutting profile and said connection portion are faced, said elongated hole defined by connection belt that extends opposite to said at least one cutting profile.

5. The method according to claim 4, wherein said plane cutting portion provides a second elongated hole, for lightening, in particular the plane cutting portion provides a band portion that has a first end connected to a first connection belt and a second end that is connected to a second connection belt, the band portion extending obliquely between the first connection belt and the second connection belt, in order to have said cutting profile facing towards the first connection belt.

6. The method according to claim 5, wherein said band portion has also a cutting profile facing towards the second connection belt in case of reciprocating movement of the blade.

7. The method according to claim 1, wherein said conveying is selected from the group consisting of: a stepped conveying of said or each logs on a respective cutting cradle in said cutting region, said stepped conveying being carried out when in said cutting region said connection portion is moving and being stopped when in said cutting region said cutting portion is moving, so that said cutting profile that extends obliquely cuts said logs obtaining cut portions for a length corresponding to one step; and a continuous conveying of said or each logs according to a conveying direction on a respective cutting cradle in said cutting region, in said cutting region a conveying device being provided that causes a bending of said blade in said conveying direction between a first position and a second position, said conveying device causing said bending in said conveying direction from said first position to said second position in a way that is synchronous to said continuous conveying of said or each logs when in said cutting region said cutting portion is moving, so that said cutting profile that extends obliquely cuts said logs obtaining cut portions having a same length as a predetermined conveying length, and said conveying device causing said bending in an opposite direction to said conveying direction from said second position to said first position when in said cutting region said connection portion is moving, so that said connection portion moves next to said logs without impeding said continuous conveying of said log.

8. The method according to claim 7, wherein two respective conveying devices are provided, which move integrally in an alternated way, but according to two opposite phases on two opposite sides of said blade causing a bending of the blade according to said conveying direction or in an opposite conveying direction in according to phases opposite to each other, in said bending, the tension of the blade not requiring particular compensations, since said blade is fixedly tensioned.

9. The method according to claim 1, wherein said blade is looped around a plurality of flywheels or pulleys arranged as a polygon, in particular a quadrilateral, wherein, on a side of said polygon a sharpening device is provided, and wherein on at least another side of said polygon at least one cutting region is provided, in particular said cutting region arranged downstream of storage region of logs downstream of a production line of paper material comprising at least one rewinding machine, or an interfolding machine, or a machine for stacking packages of folded sheets, in particular said cutting region being configured in a way selected from the group consisting of: a cutting region comprising downstream of a downhill conveying path along which cut portions of logs move, wherein a first side of said polygon consisting of said blade crosses said cutting region upstream of said downhill conveying path, and a second side of said polygon consisting of said blade is opposite to said first side and extends above said downhill conveying path so that said blade does not impede said cut portions of log; a cutting region and a conveying path of logs upstream of said cutting region, wherein a first side of said polygon consisting of said blade crosses said cutting region, and a second side of said polygon consisting of said blade is opposite to said first side and extends upstream of said conveying path so that said blade does not impede logs being cut; a cutting region and two conveying paths of logs upstream of said cutting region, wherein a first and a second side of said polygon consisting of said blade cross said conveying paths in two respective cutting regions, in order to cut the logs coming from said two conveying paths, and a third side of said polygon consisting of said blade passes above two respective downhill conveying paths so that said blade does not impede respective cut portions of log; and a cutting region wherein said polygon is arranged in a vertical plane and said blade has at least one couple of cutting profiles opposite to said longitudinal axis, upstream of said cutting region there being provided a conveying path of at least two logs so that said at least two logs are located at opposite sides with respect to said blade in said cutting plane.

10. The method according to claim 1, wherein in said cutting region a pressing element is provided selected from the group consisting of: a pressing element comprising two conveyor belts facing each other that move in said conveying direction, for carrying out said moving of said logs, and in an orthogonal direction to said conveying direction, for carrying out a blocking stroke of said logs simultaneously to the movement of said cutting portion of said blade in said plane, an adjustment mechanism for adjustment in height of said conveyor belts being provided, in order to adjust a rest position of said conveyor belts before carrying out said blocking stroke and adapting to different diameters of said log; and a pressing element comprising an upper pressing member having at least one couple of plane upper pressing plates, configured to contact a respective generatrix of said logs above said cradle, said upper pressing member carrying out a blocking movement in a direction orthogonal to said conveying direction according to a blocking stroke of simultaneously to the movement of said cutting portion of said blade in said cutting plane, there being provided an adjustment mechanism in height of said upper pressing member, in order to adjust a rest position of said plane pressing plates before carrying out said blocking stroke of and adapting to different diameters of said log.

11. The method according to claim 1, wherein a sharpening step is provided of said blade, wherein said sharpening step is carried out only on the cutting profile of said cutting portion and is not made on said connection portion, in particular said sharpening step being selected from the group consisting of: sharpening by a couple of abrasive sharpening sticks arranged slanted and opposite to each other; sharpening by a sharpening knob mounted to an oscillating arm configured to oscillate under the push of said knob in order to follow and sharpen said cutting profile during the movement of said cutting portion, and sharpening by an elongate abrasive strip mounted to a support arranged laterally so that said cutting profile contacts with an own side face against said strip so that different portions of said cutting profile slide against different portions of said strip.

12. A plant for cutting logs that is configured for carrying out the method according to claim 1.

13. A blade for cutting logs that is configured for carrying out the method according to claim 1.

14. A plant for cutting logs that is configured for carrying out the method according to claim 2.

15. A plant for cutting logs that is configured for carrying out the method according to claim 3.

16. A plant for cutting logs that is configured for carrying out the method according to claim 4.

17. A blade for cutting logs that is configured for carrying out the method according to claim 2.

18. A blade for cutting logs that is configured for carrying out the method according to claim 3.

19. A blade for cutting logs that is configured for carrying out the method according to claim 4.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0080] The invention will be now shown with the following description of its exemplary embodiments, exemplifying but not limitative, with reference to the attached drawings in which:

[0081] FIGS. 1-4 show four successive cutting steps of the method according to the invention;

[0082] FIGS. 5-10 show exemplary embodiments of a cutting blade according to the invention;

[0083] FIGS. 11-11A, 12, 13 and 13A show exemplary embodiments of a blade cutting path with synchronous movement of the blade and continuous movement of the log;

[0084] FIGS. 14-19 show possible layouts of a blade path connected to the method according to the invention provided at the exit of production lines of logs;

[0085] FIGS. 20-23 show two possible exemplary embodiments of alternated cut;

[0086] FIGS. 24 and 25 show two possible exemplary embodiments of clamping devices used in combination with the method according to the invention;

[0087] FIGS. 26-29 show exemplary embodiments of sharpening systems connected to the method according to the invention.

DESCRIPTION OF PREFERRED EXEMPLARY EMBODIMENTS

[0088] With reference to FIGS. 1-4 a method according to the invention for cutting a log 1 comprises the steps of:

[0089] prearranging at least one cutting region 2 configured to be crossed by at least one log 1 according to a conveying direction transversal to a cutting plane 3, coincident or parallel to the rectangle indicated as 2 in FIG. 1 with a dashed line;

[0090] prearranging a blade 10 having a longitudinal axis 11 and comprising:

[0091] a plane cutting portion 12 and a connection portion 13 connected to the cutting portion 12;

[0092] the cutting portion 12 having a cross section of minimum width 12a, a cross section of maximum width 12b and at least one cutting profile 12c that extends obliquely between the cross section of minimum width 12a, and the cross section of maximum width 12b, so that the cutting profile 12c forms an angle with respect to the longitudinal axis set between 1° and 60°, in particular between 1° and 30°, much more in particular, between 1° and 10°, for example between 1 and 8°;

[0093] the cutting profile 12c has a cutting height 15 in a direction that is orthogonal to the longitudinal axis 11 equal to at least the difference between the cross section of maximum width 12b and the cross section of minimum width 12a, and the connection portion 13 has width less than or equal to the minimum width 12a;

[0094] causing a movement 20 of the blade 10 parallel to the longitudinal axis 11, so that the connection portion 13 and the cutting portion 12 cross in turn the cutting region 2 and the cutting portion 12 cross the cutting region 2 according to the cutting plane 3;

[0095] conveying the log, or each log, 1, on a respective cutting cradle 4 in the cutting region 2, the or each log 1 having a height less than the cutting height 15 so that the cutting profile 12c that extends obliquely cuts the log 1 when advancing, by contacting the log and then cutting the log, in order to obtain cut portions 5 having a same length as a predetermined conveying length.

[0096] In case of logs 1 of large diameter, in a way not shown but easily implemented by a skilled person, it is also possible that the cradle 4 causes a rotation of the log 1 about itself when the cutting profile 12c passes above the cradle 4. In this case, the cutting height 15 can be equal to half the diameter of the log 1, or equal to the difference between the radius of the log 1 and the radius of the core of the log 1.

[0097] With reference to FIG. 5, the blade can have the cutting portion 12 having a single cutting profile 12c (FIG. 5). In the cutting region logs 1 can be fed, which are arranged as shown in FIG. 5 or as in FIGS. 1-4, or arranged in a similar way to FIG. 9 (as described hereinafter) aligned in respective cradles 4, providing up to, for example, eight cradles parallel to each other, also that they can be each cradle 4 with log of different diameter, or of different material.

[0098] Alternatively, the blade can have cutting portion 12 having two cutting profiles 12c,12′c opposite to each other with respect to the longitudinal axis 11 (FIG. 6). This way, in the cutting region 2 logs 1 can be fed opposite to each other with respect to the longitudinal axis 11, so that the logs are cut from both the respective cutting profiles 12c,12′c. Such solution can be particularly suited for industrial rolls or jumbo rolls.

[0099] In a further solution, as shown in FIGS. 20-23, the blade can have the cutting portion 12 with two cutting profiles 12c,12″c, arranged at a same side with respect to the longitudinal axis 11, the two cutting profiles 12c,12″c cutting the log 1 (arranged on cradles not shown, for example similar to the cradles 4 of FIGS. 1-4) when the blade 12 carries out the movement in respective opposite directions.

[0100] It is also possible, in a way not shown but easily implemented by a skilled person, to combine the above described profiles, for example a blade with two cutting profiles arranged at a same side with respect to the longitudinal axis as shown in FIGS. 20 and 22 and duplicated on the other part of the longitudinal axis as shown in FIG. 6. Such blade can for example be used with alternated movement in a vertical plane for carrying out the cut on two cradles both with movement of the blade towards below and towards the above.

[0101] As shown in FIGS. 7 and 8, the blade can also have (FIG. 7) a plane cutting portion 12 and a connection portion 13 connected to the cutting portion 12 consisting of a single plane band, which can be a band continuously looped about at least two flywheels (for example implemented by a skilled person as the flywheels 23a,23b of the FIGS. 14-19), which provide a continuous movement, or a reciprocating band, as that of FIGS. 20-23. Such solution of continuous band is particularly advantageous for simplicity for making the blade, which can be a simple band of a shaped sheet, and sharpened only on the cutting profile, even very thin (a few tenth of mm) in such a way that it does not need to be sharpened further.

[0102] Alternatively, a blade (FIG. 8) can be provided, where the plane cutting portion 12 comprises a plane band 12 and the connection portion 13 is a connecting element connected to the plane cutting portion, and where the blade can be selected from the group consisting of: a continuous blade looped about at least two flywheels that provide a continuous movement, a discontinuous blade having reciprocating movement, and where the connection portion 13 can be selected from the group consisting of: a band portion, a chain portion, a rope portion, a belt portion. The connection portion 13 can be connected to the cutting portion for example by a link 17, or the belt, chain, rope, in addition to form the connection portion 13, can also extend integrally along the cutting portion 12, to ensure continuity of traction, through pulleys, gears, spools, not shown, which provide a torque and guide the path of the cut or the blade path. Such solution makes it possible to replace easily the cutting portion without to replace also the connection portion.

[0103] The examples of FIGS. 7 and 8 can be fixed at a desired blade as above described or as described hereinafter, both with only one cutting profile that with two cutting profiles, in a way easily implemented by a skilled person.

[0104] In case of the example of FIG. 8, in a way easily implemented by a skilled person, the connection portion can be chosen as a discontinuous element, consisting of connecting portions 13 that is are discontinued at the connections 17 with the plane cutting portion, or alternatively as a continuous element 13 that extends also between the connections 17 of the plane cutting portion 12 parallel to it.

[0105] Alternatively, or in addition, as shown in FIGS. 9, 9A and 10, for cutting logs 1 the blade can comprise a conveying portion 19 having a larger width than the cutting portion, the conveying portion 19 defining at least one elongated hole 18 on which the at least one cutting profile 12c and the connection portion face, the elongated hole defined by a connection belt 18a that extends opposite to at least one cutting profile 12c. This way, both with a single cutting profile 12c (FIG. 9) as well as with more cutting profiles 12c,12′c (FIG. 10) for each connection portion 13, on the one hand a band 19 is obtained with fixed width even if maintaining a cutting profile 12c or 12c,12′c in the cutting portion 12 with adjustable cross section, allowing to convey the blade 10 in a way that is very steady and quick, owing to the presence of the connection belt 18a.

[0106] The conveying the log 1, or each log 1, on a respective cutting cradle 4 in the cutting region 2, can be made stepwise, each step being carried out when in the cutting region 2 the connection portion 13 is moved, and is then stopped when in the cutting region 2 the cutting portion 12 moves, so that the cutting profile 12c that extends obliquely cuts the log 1 obtaining cut portions 5 for a length corresponding to one step.

[0107] In the possible embodiment of FIG. 9A the cutting portion 12 is arranged in turn in an elongated hole, with an elongated hole 18′, which allows lightening the cutting portion 12 same. In particular, the elongated hole 18 can be a first elongated hole and the plane cutting portion 12 provides a second lightening elongated hole 18′. In this case, the plane cutting portion 12 provides a band portion 12d that has a first end 12′d connected to the first connection belt 18a and a second end 12″d that is connected to a second connection belt 18′a, the band portion 12d extending obliquely between the first connection belt 18a and the second connection belt 18′a, in order to have said cutting profile 12c facing towards the first connection belt 18a. In a particular production configuration, the band portion may also have a cutting profile facing towards the second connection belt, in case of reciprocating movement of the blade, the band portion extending obliquely between the first connection belt and the second connection belt.

[0108] In a specific example of an exemplary embodiment of FIG. 9A, not shown but easily implemented by a skilled person, the band portion 12d may also have a cutting profile facing towards the second connection belt 18′a, in case of reciprocating movement of the blade, in this case at least one further cradle can be provided, or feeding logs in the second elongated hole 18′.

[0109] Also the solutions of FIGS. 9, 9A, 10 can provide the possible increase of the number of cradles, for example up to eight cradles, or more, and the subsequent evacuation of a corresponding number of cut portions (see for example the layout of FIGS. 14-17).

[0110] Alternatively to what above defined, the conveying of log 1 can be continuous (FIGS. 11-13). The continuous conveying can be made according to a conveying direction 6 in FIGS. 11, 11A and 12, or in two opposite directions for conveying two separate series of log 1, as described hereinafter.

[0111] With reference to FIGS. 11,11A, on each cutting cradle of logs 1 in the cutting region 2, by using a preferred exemplary embodiment of the blade 10 as above described, in order to avoid interferences with the cutting portion 13, in the cutting region 2, a conveying device 40 can be provided, for example consisting of small rollers 41 that roll on the blade 10 and that move integrally in an alternated way according to arrow 42. This way, the conveying device 40 causes a bending of blade 10 in the conveying direction 6 between a first position 40A and a second position 40B. In this bending, the tension of the blade is for example compensated by a blade tensioner 42, which can oscillate according to an arrow 42a.

[0112] According to this exemplary embodiment, when the conveying device 40 causes the bending in the direction 7b in the same conveying direction 6 from the first position 40A to the second position 40B (FIG. 11A), this bending is carried out with a movement synchronous to the continuous conveying of the log 1 in the direction 6, and this synchronous movement is carried out when in the cutting region 2 the cutting portion 12 moves, so that the cutting profile 12c that extends obliquely, cuts the log 1 obtaining cut portions 5 having a same length as a predetermined conveying length.

[0113] Instead, with reference to FIG. 1,2, the conveying device 40 can cause the bending in an opposite direction 7a to the conveying direction 6 from the second position 40B to the first position 40A when in the cutting region 2 the connection portion 13 moves, so that the connection portion moves next to the log 1 without avoid the continuous conveying of the log 1. Such movement 7a can be made in the quickest possible way, for increasing the production rate and the need of a connection portion 13 as short as possible, while the pitch of the cut is determined by the combination between the speeds of movement according to arrows 6 and 7a.

[0114] In these exemplary embodiments with continuous movement of the log 1, alternatively to a blade tensioner, the bending of blade 10 caused by the variation of position of the conveying device 40 can be compensated, in a way not shown but easily implemented by a skilled person, with the movement of at least one, or both the flywheels 23a, 23b, or other flywheels arranged for rotating the blade 10, in synchronism with the movement of the conveying device 40. In this case, the drums or the flywheels should be mounted to a support whose axis can move parallel to itself.

[0115] With reference to FIGS. 13 and 13A, in a possible exemplary embodiment of the two solutions of FIG. 11, 11A and 12, in order to avoid the need of a blade tensioner, and to double the production rate, two respective conveying devices can be provided 40, 40′, similar to that above described, that move integrally in an alternated way, but according to two opposite phases shown respectively in FIG. 13A and 13. This way, the two conveying devices 40, 40′ cause a bending of the blade 10 in the conveying direction 6 or in the conveying direction 6′ between the two above described positions, or in a similar way to that described in FIG. 12, provided according to phases opposite to each other. In this bending, the tension of the blade 10 does not require further compensations, since the blade is fixedly tensioned. Furthermore, the production rate is doubled. Further sides of the blade 10 and further dispositions of the cradles of the logs 1 can be implemented by the skilled person, and preferably even with further systems 40 when the blade 10 extends on a wide surface, for example polygonal with more than four sides.

[0116] With reference to the figures from 14 to 19, in possible production layouts, the blade 10 is looped around a plurality of flywheels or pulleys 23a,23b,23c,23d arranged as a polygon 100, in particular a quadrilateral, wherein, on an side of polygon a sharpening device is provided 50, and wherein on at least another side 100a of polygon at least one cutting region is provided 2. In particular, the cutting region 2 is located downstream of a storage region 60 of log ready to be cut, in turn, downstream of a production line of paper material comprising at least one production machine, for example a rewinding machine, or an interfolding machine, or a machine for stacking packages of folded sheets. Other machines can be unwinding, transversal cutting, gluing machines, etc., as well known in plants of paper converting.

[0117] In a first possible exemplifying embodiment (FIG. 14), downstream of the cutting region 2 a downhill conveying path 8 is provided along which cut portions 5 of the logs move. A first side 100a of polygon 100 of the path of blade 10 crosses the cutting region 2 upstream of the downhill conveying path 8, and a second side 100b of the polygon consisting of the path of blade 10 is opposite to the first side 100a and extends above the downhill conveying path 8 so that the blade 10 has the cutting edge 12 with the cutting profile 12c that do does not impede the cut portions of log 5, whereas when the cutting edge 12 with the cutting profile 12c passes through the side 100a of polygon 100, cuts the log 1 into portions 5. Such solution allows a very high production rate.

[0118] Another alternative layout shown in FIG. 15 provides upstream of the cutting region 2 a conveying path 9 of log 1, for example providing up to eight cradles of log 1 or even more. In this layout a first side 100a of polygon 100 of the blade path, consisting of the blade 10 and of the drums or pulleys 23a,23b, etc., crosses the cutting region 2 so that the cutting profile 12c cuts them into rolls 5, and other sides of polygon 100 extend upstream of and at the sides of the conveying path 9, so that the blade 10 does not impede cut portions of log 1 . The length of the sides of polygon 100 does not affect the efficiency of the method, since the angle of the cutting portion 10 can be also of a few degrees, up to 1 degree, and the speed 20 of the blade (FIG. 1-4) can be also of hundreds metres per minute.

[0119] In a further layout shown in FIGS. 16 and 17, there are provided two cutting regions 2 and two conveying paths 9 of logs upstream of the cutting region, wherein a first and a second side 100a and 100b of polygon 100 provide blade 10 crossing the conveying paths 9 of log 1 in two respective cutting regions, in order to cut the log coming from the two conveying paths, and a third side 100c of polygon 100 passes above two respective paths of downhill evacuation 8a,8b of cut portions, so that the blade 10 does not impede respective cut portions of log 1. Such solution allows, with a single blade 10, a production rate doubled with respect to FIG. 14 or 15, with up to 16 logs (or more) cut by a single passage of blade 100. Obviously, other similar layouts and with a production rate even higher can be provided similarly, with a polygon with different shape and different size, but easily obtainable by a skilled person.

[0120] With reference to all these exemplary embodiments, with references 60 and 61-65 a production line of paper material is shown comprising at least one machine for paper converting, for example a rewinding machine, or an interfolding machine, or a machine for stacking packages of folded sheets. Other machines can be unwinding machines, transversal web cutting machines, gluing machines, etc., as well known in paper converting plants.

[0121] With reference to the FIGS. 18 and 19, a cutting region 2 can be provided wherein polygon 100 is arranged in a vertical plane and the blade 10 has at least one couple of cutting profiles 12c,12′c opposite to the longitudinal axis (as described for FIGS. 6-9). Upstream of the cutting region 2 there being provided a conveying path 9 of at least two logs 1, in a way in which they are located at opposite sides with respect to the blade 10 in the cutting plane. Such solution is particularly suitable to cut industrial rolls very thick and jumbo rolls.

[0122] In possible exemplary embodiments according to FIGS. 24 and 25, in the cutting region 2 in the various ways above described, at the cradles 4 an element of pressure 70 can be provided, commonly called presser.

[0123] In a possible solution, as shown in FIG. 24, the pressing element 70 comprises an upper pressing member 73 having at least one couple of plane upper pressing plates, configured to contact a respective generatrix of the log (not shown), opposite to the cradle 4. This way, the upper pressing member 73 can carry out a blocking movement 70a in a direction that is orthogonal to the conveying direction, according to a blocking stroke simultaneously to the movement of the cutting portion into the cutting plane. There can be provided a mechanism 74 of adjustment in height of the upper pressing member, which allows both adjusting a rest position of the plane pressing plates and adapting to different diameters of the log, carrying out the stroke of blocking/unlocking the log. Advantageously, as shown in the figure, a pressing device 70 can be provided of a support structure 75 of a plurality of cradles 4 adjacent to each other and relative pressing devices.

[0124] In another possible solution, as shown in FIG. 25, the pressing element 70 comprises two conveyor belts 71a, 71b facing each other that move for pushing a log not shown in the conveying direction 6, in order to cause it to advance. Furthermore, the belts 71a, 71b can move in a direction 70a orthogonal to the conveying direction 6, for carrying out a blocking stroke of the log, simultaneously to the movement of the cutting portion of the blade 10 in the cutting plane by it defined. For carrying out the blocking movement in the direction 70a, there can be provided a mechanism of pushing and adjusting in height 72 the conveyor belts 71a, 71b, in order to both adjusting a rest position of the conveyor belts and adapting to different diameters of the log, as well as carrying out the blocking stroke during the movement of the cutting portion of the blade 10. Such a configuration of the clamping device can also be used in case of continuous movement, according to the FIGS. 11-13.

[0125] In possible embodiments, according to FIGS. 26-29, a step can be provided of sharpening the blade, carried out only on the cutting profile 12c of the cutting portion and not on the connection portion 13. This determines that portions of the blade are not sharpened, and then easily handled in case of mounting and maintenance.

[0126] In particular, the sharpening step can be made through at least one sharpening knob 52 mounted to an oscillating arm 53, configured to oscillate by translating (FIGS. 26,26a) or by rotating (FIG. 27) with respect to a fixed frame, under the push of the knob 52, in order to follow the cutting profile 12c during the movement of the cutting portion 12.

[0127] Alternatively, as shown in FIGS. 28 and 28A, the sharpening can be made through a couple of abrasive sharpening sticks 51 arranged slanted and opposite to each other, and configured for closing or widening from each other according to arrow 51a respectively, for carrying out the sharpening of the cutting profile 12c (normally called bevel) or releasing the blade when the sharpening has not to be done.

[0128] As further alternative, as shown in FIGS. 29, 29A, the sharpening can be made by an elongated abrasive strip 55 mounted to a support 55a having an approaching movement and arranged laterally so that the cutting profile 12c contacts with an own side face against the strip 55, allowing that different portions of the cutting profile 12c contact different portions of the strip 55.

[0129] The foregoing description exemplary embodiments of the invention will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such embodiment without further research and without parting from the invention, and, then it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiments. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is intended that the expressions or the terminology used have object purely descriptive and, for this, not limitative.