Cutting machines and methods are disclosed for cutting rolls or so-called logs of wound paper, for instance tissue paper, for producing rolls of toilet paper, kitchen towels and the like.
In many industrial fields rolls or logs of a continuous web material are produced, and then divided, by means of so-called cutting machines, into a plurality of logs of smaller axial dimensions. Typically, in the production of tissue paper rolls, for example rolls of toilet paper, kitchen towels and the like, a roll of great diameter (so-called parent reel) is processed into a plurality of rolls or logs, whose axial length is equal to the axial length of the parent reel and whose diameter is equal to the diameter of the rolls to be packed and sold to the end user. The logs are cut into a plurality of rolls by means of cutting machines, usually provided with one or more disc-shaped rotating blades.
U.S. Pat. No. 5,799,555 discloses a cutting machine for cutting tissue paper logs and producing rolls in fast sequence. This known machine comprises a rotating orbital head provided with a disc-shaped rotating blade.
In some cutting machines, for improving productivity two disc-shaped rotating blades are provided, arranged at diametrically opposite positions. U.S. Pat. No. 4,041,813 discloses, for example, a cutting machine with a head or orbital gib rotating around a substantially horizontal axis. The head carries two disc-shaped rotating blades that are diametrically opposite, i.e. arranged at opposite positions with respect to the rotation axis of the head. Two cuts of the log are therefore performed at every rotation of the head.
US 2006/0000312 discloses a cutting machine provided with a rotating plate, on which three disc-shaped rotating blades are arranged equidistant, for further increasing productivity.
U.S. Pat. No. 8,037,794 discloses a cutting machine provided with a rotating head supporting two pairs of disc-shaped rotating blades. Each pair of disc-shaped rotating blades is constituted by two coaxial blades arranged at an adjustable reciprocal axial distance. In this way, it is possible to perform four cuts of the log at every rotation of the head. The machine disclosed in this publication has high productivity and allows to adjust the distance of the disc-shaped coaxial blades based on the axial dimension of the rolls to be produced. However, in some cases the machine can have some drawbacks, due to the fact that the two coaxial blades act on the single log simultaneously. This can cause a compressive deformation of the material of which the log is made, with consequent damages to the finished product. This is due to the fact that the disc-shaped cutting blades of these machines have a bi-conical shape, whose thickness increases from the periphery towards the center. Above all when the blade diameter is reduced due to wear, the thickness of the blade is not negligible and, when penetrating the material to be cut, the blade axially presses it. This is a problem especially in the case of rolls wound around tubular winding cores, made for example of cardboard, as the winding cores may be irreversibly deformed due to compression, with consequent scraps production. A further inconvenience is that replacing the worn blades, especially the internal ones, is complex and difficult.
There can be similar needs also when cutting other types of articles or products that are elongated in an axial direction, which shall be divided into products with smaller axial dimension.
A need therefore exists for providing a machine and a method for cutting logs or rolls of wound web material, for example tissue paper logs, in particular tissue paper wound on cardboard cores, or other elongated products, that partially or completely overcome the drawbacks of the known machines, ensuring at the same time high productivity.
According to one aspect, a cutting machine is disclosed for cutting elongated product, comprising a feed path for the products to be cut. The feed path may be single or multiple, i.e. a system can comprise only one feed channel for moving the products, aligned longitudinally one after the other, or two or more channels, adjacent to one another, for moving simultaneously more products in parallel, the products being, if necessary, offset with respect to one another in longitudinal direction. The products move along the feed path in a direction substantially parallel to their longitudinal extension.
Feed members for feeding the products are also provided along the feed path. In case of a multiple feed path, for example a path with a plurality of parallel adjacent channels, the feed members may be so configured as to move a plurality of products forward, if necessary offset with respect to one another in longitudinal direction, i.e. in feeding direction.
The machine may also comprise a unit rotating around a rotation axis. The rotating unit may carry at least a first disc-shaped cutting blade and a second disc-shaped cutting blade. The first disc-shaped cutting blade and the second disc-shaped cutting blade have the respective rotation axes parallel to each other and which can be substantially parallel to the rotation axis of the rotating unit. In other embodiments, the rotation axes of the disc-shaped cutting blades may be skewed with respect to the rotation axis of the rotating unit.
The rotation of the rotating unit around the rotation axis causes an orbital movement of the first disc-shaped cutting blade and of the second disc-shaped cutting blade along substantially parallel trajectories intersecting the feed path of the products.
Advantageously, the first disc-shaped cutting blade and the second disc-shaped cutting blade are offset from each other in a direction parallel to the rolls feed path and parallel to the rotation axis of the rotating unit. Consequently, the trajectories of the two disc-shaped rotating blades may lie on two substantially parallel planes, offset from each other along the axial direction, i.e. the direction defined by the rotation axis of the rotating unit.
The first disc-shaped cutting blade and the second disc-shaped cutting blade may be also angularly offset from each other with respect to the rotation axis of the rotating unit. Due to the angular offset between the two disc-shaped cutting blades, the blades interact with the product to be cut in staggered manner, i.e. one of the two disc-shaped rotating blades at least partially starts cutting and finishes cutting in advance with respect to the cut operation performed by the other disc-shaped rotating blade.
It is possible, for example, to set such an angular offset of the two disc-shaped cutting blades such that the second disc-shaped cutting blade starts cutting the product when the first disc-shaped cutting blade has already cut, partially or completely, the product. In this way, the compressive deformation of the material of which the product is made, due to the thickness of the disc-shaped cutting blades, is reduced with respect to the case where the two disc-shaped cutting blades are coaxial, as in the prior art machines. In this latter case, the two coaxial blades simultaneously penetrate the product, causing the compression of the material of which it is made, to an extent proportional to the thickness of the two disc-shaped cutting blades. The angular offsetting of the disc-shaped cutting blades results in a staggered action of the two disc-shaped cutting blades on the products, and therefore in a reduced crushing of the material of which the product is made following the penetration of the disc-shaped cutting blades therein.
In some embodiments, the feed members may comprise pushing members carried by continuous flexible members, for example belts or chains. If only one feed channel is provided, along which the products to be cut move forwards sequentially one after the other, a single flexible member is enough, to which one or more pushing members are fixed. If the feed path comprises two or more parallel adjacent channels, it could be useful to provide a plurality of motors for moving the products forwards in the single channels in an axially offset manner.
In some embodiments, for example, a continuous flexible member for each channel can be advantageously provided, and one or more pushing members may be fastened on each continuous flexible member. Each flexible member may be provided with a motor, independent from the motors of the other flexible members. The motors can be controlled by a single central control unit, imparting, to the products in the single channels, a staggered forward movement from a channel to another. This allows to start the forward movement of each product in the respective feed channel as the disc-shaped cutting blades have exited from the product, even if the cut of the products in the adjacent channels has not been yet completed or done.
Each disc-shaped cutting blade can rotate around a rotation axis that can be substantially parallel to the main rotation axis, around which the rotating equipment rotates.
In some embodiments, the first disc-shaped cutting blade and the second disc-shaped cutting blade are offset from each other by an angle comprised between 5° and 120°, preferably between 10° and 90°, more preferably between 15° and 45°, for example between 20° and 45°. The offset angle between the disc-shaped cutting blades may be fixed or adjustable. This allows, for example, to adapt the machine configuration to the diameter of the products to be cut and/or to the number of adjacent parallel channels, along which the products move forward.
Such a machine is particularly advantageous for cutting wound paper logs, for example logs of tissue paper, for producing rolls of toilet paper, kitchen towels and the like. In fact, these rolls are very delicate and can be damaged if excessively compressed by the cutting blades in axial direction. Moreover, these rolls are usually formed around tubular winding cores, often made of cardboard or plastic. The tubular winding cores may be damaged by the compression due to the simultaneous penetration of two disc-shaped cutting blades into the log to be cut. For example, the tubular winding cores may be crushed thus reducing the hollow space inside the roll. With the two disc-shaped cutting blades arranged axially and angularly offset as described above, it is possible to reduce the compressions in axial direction of the material of which the log is made, thus reducing the risks of producing rejects.
In some embodiments, the offset of the first disc-shaped cutting blade and of the second disc-shaped cutting blade in the feed path direction can be adjusted, to have cut products of different axial length.
In some embodiments, the first disc-shaped cutting blade and the second disc-shaped cutting blade can be carried by a first arm and by a second arm, respectively. The first arm and the second arm may be adapted to rotate integrally with each other around the rotation axis. The first arm and the second arm may also be coupled together by means of an elongation mechanism transmitting the rotation between the first arm and the second arm and allowing to vary the distance between the first arm and the second arm parallel to the rotation axis.
The machine may comprise an actuation shaft for actuating the first disc-shaped cutting blade and the second disc-shaped cutting blade. The actuation shaft may be supported in the first arm and in the second arm. In some embodiments, a first drive may be provided for transmitting the rotation motion from the actuation shaft along the first arm to the first disc-shaped cutting blade. A second transmission may be further provided for transmitting the rotation motion from the actuation shaft along the second arm to the second disc-shaped cutting blade. Each transmission can comprise, for example, a flexible member, such as a chain or preferably a belt, for example a toothed belt.
In some embodiments, the shaft for actuating the first disc-shaped cutting blade and the second disc-shaped cutting blade may be supported inside a hollow drive shaft, which is torsionally connected to the first arm. In this way, the hollow drive shaft, connected for example to a first actuation motor, drives the first arm in rotation and the first arm drives the second arm in rotation through a mechanical coupling. The two arms rotate integrally around the rotation axis and make the two disc-shaped cutting blades follow the respective trajectories. The actuation shaft, supported rotatable through the hollow drive shaft, may be mechanically coupled to a second actuation motor, which drives the actuation shaft in rotation, and, through the respective transmissions, makes the two disc-shaped cutting blades rotate while orbiting along the respective trajectories.
The hollow drive shaft can be supported in a sleeve, movable orthogonally to the product feed path so as to move towards, and away from, the feed path. In this way, the trajectories, along which the first disc-shaped cutting blade and the second disc-shaped cutting blade orbit, may be moved towards, or away from the feed path, for example in order to recovery the wear of the disc-shaped cutting blades due to the grinding thereof. The gradual movement of the orbital trajectories of the disc-shaped cutting blades towards the product feed path may be obtained also with other suitable mechanisms, adapted to move the rotation axis of the rotating unit, on which the disc-shaped cutting blades are mounted, towards the feed path of the products to be cut.
To achieve a better cut, in terms of quality, a holding device for the products can be arranged along the product feed path, adapted to hold the products laterally or externally during cutting. The holding device can comprise three holding members arranged in sequence along the feed path, between which two passages or spaces are formed for the first disc-shaped cutting blade and for the second disc-shaped cutting blade, respectively. An intermediate holding member can be provided between an upstream holding member and a downstream holding member, with respect to the product feeding direction along the feed path.
The intermediate holding member may have an axial dimension, i.e. a dimension parallel to the product feeding direction, which is adjustable according to the distance in axial direction of the two disc-shaped cutting blades, i.e. according to the distance of the trajectories along which the two disc-shaped cutting blades orbit. This distance depends on the axial dimension of the articles obtained by cutting the elongated products moving forward along the feed path. In the case of logs and rolls obtained from the cut of the log, the distance depends on the axial dimension of the rolls to be obtained. The lengthening or shortening of the intermediate holding member results in the change, in axial direction, of the distance between the two passages for the first disc-shaped cutting blade and for the second disc-shaped cutting blade, defined by the holding member.
For example, in some embodiments the intermediate holding member can be made of two telescopic portions, at least one of which is movable parallel to the feed path. The upstream holding member or the downstream holding member can be integral with one of the two telescopic portions of the intermediate holding member. In some embodiments, the upstream holding member is integral with one of the two telescopic portions of the intermediate holding member, whilst the downstream holding member is integral with the other telescopic portion of the intermediate holding member.
According to a further aspect, disclosed herein is a method for cutting products having a first length into products having a second length, the first length being greater than the second length. The products to be cut can be, for example, logs of paper, for instance tissue paper. The products obtained by cutting can be rolls or small rolls of toilet paper, kitchen towels or the like. In embodiments disclosed herein, the method comprises the following steps: moving forward at least one product along a feed path in a direction substantially parallel to the longitudinal extension of the product; moving a first disc-shaped cutting blade and a second disc-shaped cutting blade around a rotation axis along respective orbital trajectories intersecting the feed path, the first disc-shaped cutting blade and the second disc-shaped cutting blade being angularly offset from each other with respect to the rotation axis and the two orbital trajectories being axially offset from each other along the rotation axis in order to perform two cuts of an elongated product at every rotation of the disc-shaped cutting blades around the rotation axis.
In embodiments of the method disclosed herein, the blades rotate integrally with each other along the orbits, and the orbits are preferably equal to each other. The orbits may be elliptical or, preferably, circular.
In some embodiments, the first disc-shaped cutting blade and the second disc-shaped cutting blade are offset from each other by an angle comprised between 5° and 120°, preferably between 10° and 90°, more preferably between 15° and 45°.
In possible embodiments of the method disclosed herein, the first disc-shaped cutting blade and the second disc-shaped cutting blade are angularly offset from each other by such an angle that, for at least a portion of the orbital motion thereof, both the blades are engaged in the products.
In particular, when the products to be cut are logs wound on tubular winding cores, the disc-shaped cutting blades are preferably so offset that, when cutting a log, at each instant only one of said first disc-shaped cutting blade and second disc-shaped cutting blade is engaged in the tubular winding core. In this way, the tubular winding core is not excessively pressed.
In a known manner, the products to be cut can move forward with continuous or intermittent motion along the feed path. In case the forward movement is continuous, it can be at constant or, preferably, variable speed, so that feeding occurs at lower speed when the blades are engaged in the product to be cut and, vice versa, at greater speed when the blades are not engaged in the product to be cut.
In some embodiments of the method described herein, the disc-shaped cutting blades are axially offset by a length equal to the second length of the cut products, i.e. for example a length equal to the axial dimension of the rolls obtained by cutting the log; at every rotation of the disc-shaped cutting blades along the trajectories, the product to be cut moves forward by one step equal to twice the second length.
In other embodiments of the method disclosed herein, the disc-shaped cutting blades are axially offset by a length equal to the triple of the second length, i.e. for example of the axial length of the rolls obtained by cutting the log; at every rotation of the disc-shaped cutting blades along the trajectories, the product to be cut move forward by a step equal to twice the second length.
By arranging the blades offset from each other by an angle smaller than 180°, there is advantageously more time for moving the products to be cut forward between a cutting operation and the following one. In the prior art machines, providing for a rotating unit on which two disc-shaped cutting blades are arranged offset from each other by 180° with respect to the rotation axis of the rotating unit, the time for moving forward the product to be cut between a cut and the subsequent one is relatively short. On the contrary, with two blades that are angularly nearer to each other and axially offset from each other, it is possible, on one hand, to perform two sequential cuts or two almost overlapping and axially offset cuts, so that the members for moving forward the logs, or other products to be cut, have much time for moving the products forward up to the subsequent pair of cuts.
In this way a machine can be provided with high productivity and reduced inertial stresses, thanks to the fact that it is not necessary to impart too high accelerations to the products to be cut.
The invention shall be better understood by following the description and the accompanying drawing, which show a non-limiting example of embodiment of the invention. More in particular, in the drawing:
The detailed description below of example embodiments is made with reference to the attached drawing. The same reference numbers in different drawings identify equal or similar elements. Moreover, the drawings are not necessarily to scale. The detailed description below does not limit the invention. The protective scope of the present invention is defined by the attached claims.
In the description, the reference to “an embodiment” or “the embodiment” or “some embodiments” means that a particular feature, structure or element described with reference to an embodiment is comprised in at least one embodiment of the disclosed subject matter. The language “in an embodiment” or “in the embodiment” or “in some embodiments” in the description do not therefore necessarily refer to the same embodiment or embodiments. The particular features, structures or elements can be furthermore combined in any suitable way in one or more embodiments.
In the description below, specific reference will be made to a cutting machine for cutting logs of tissue paper for forming rolls of toilet paper, kitchen towels and the like. Features described herein can be advantageously used also for producing cutting machines for cutting other products, where similar problems can occur.
In
A feed member for respective logs 7 may be associated with each feed channel 11. In the illustrated embodiment, each feed member comprises a continuous flexible member 13, for example a belt or a chain. Along the continuous flexible member 13 pushing members 15 are provided at suitable distance, to push each log 7 from the back along the feed path 5. Each continuous flexible member 13 is driven around wheels 17, two of which are shown in
In some embodiments, each flexible member 13 of each feed channel 11 can be controlled by a respective motor 19 (see
The cutting machine 1 comprises a cutting head 23 suitably supported by the bearing structure 3, for example by a substantially vertical portion 3.1 of the bearing structure 3. The cutting head 23 can comprise a rotating unit 25 rotating around a rotation axis A-A, which can be substantially horizontal and substantially parallel to the feed path 5 of the logs 7 to be cut. The rotating unit 25 may be movable according to the double arrow f25 in substantially vertical direction along the portion 3.1 of the bearing structure 3, for the purposes better described below. The motion according to the double arrow f25 allows to move the rotating unit 25 and the rotation axis A-A thereof selectively towards and away from the feed path 5 of the logs 7 to be cut.
The movement according to double arrow f25 can be controlled by an actuator 27, for example an electric motor, by means of a threaded bar 29 and a nut screw 30. This latter can be integral with a sleeve 31 or other element supporting the rotating unit 25. The upward and downward movement of the rotating unit 25 according to the double arrow f25 can be also imparted by a different driving system, for example by means of a motor and a belt or a chain, a cylinder-piston actuator, a pinion-rack mechanism or any other suitable mechanism. The upwards and downward movement of the rotating unit 25 can be preferably controlled by the central control unit 21.
The rotating unit 25 comprises a first arm 33 and a second arm 35. The first arm 33 carries a first disc-shaped cutting blade 37, rotating around a rotation axis B-B. The second arm 35 carries a second disc-shaped cutting blade 39, rotating around a rotation axis C-C. The rotation axes B-B and C-C can be parallel to each other and parallel to the rotation axis A-A of the rotating unit 25.
As shown in particular in
As shown in
The rotating unit 25 can be driven into rotation by a hollow drive shaft 41, which in turn is driven by a motor 43 through a belt 45 (see
The hollow drive shaft 41 can be supported inside the sleeve 31 and can be constrained torsionally to the rotating unit 25.
Inside the hollow drive shaft 41 a further drive shaft 51 can extend, taking motion from a second motor 53, for example through a belt 55, entrained around a drive pulley 57 and a driven pulley 59. The second drive shaft 51 transmits motion to the first disc-shaped cutting blade 37 and to the second disc-shaped cutting blade 39, for example through toothed belts, chains, gears or other transmission means. A constructive solution for transmitting rotation to the disc-shaped cutting blades 37 and 39 will be described in greater detail below with reference to
The motorization system of the disc-shaped cutting blades 37 and 39 can be configured differently from what described above, for example providing motors directly coupled with the respective shafts 41 and 51 or motors actuating respective output gears engaging toothed gears keyed on the shafts 41 and 51.
In some embodiments, the arms 33 and 35 can be provided with suitable counterweights 33A and 35A.
In the present description, the term “arms” 33 and 35 refers to any mechanical structure adapted to support the disc-shaped cutting blades 37 and 39 so as to make them orbit along trajectories centered on the rotation axis A-A.
A grinding unit can be associated with each disc-shaped cutting blade 37, 39. In particular, in
According to some embodiments, in the area of the feed path 5 where the first disc-shaped cutting blade 37 and the second disc-shaped cutting blade 39 act, external holding members for the logs 7 to be cut can be provided. The holding members form, as a whole, a holding device 71. The function of the holding device 71 is to hold the logs 7 during cutting, so that the thrust generated by the disc-shaped cutting blades 37 and 39 orthogonally to the axis of the logs 7 do not move the logs outside the feed path 5.
In some embodiments, the holding device 71 may comprise, along each feed channel 11 of the feed path 5, three holding members indicated with 71A, 71B, 71C and arranged in sequence. Between each pair of consecutive holding members a gap or passage is defined, through which one or the other of the two disc-shaped cutting blades 37 and 39 can pass. More in particular, between the holding member 71A and the holding member 71B a gap is provided, through which the disc-shaped cutting blade 37 can pass, whilst between the holding member 71B and the holding member 71C a gap is defined, through which the disc-shaped cutting blade 39 can pass.
Each holding member 71 may be designed in various ways, one of which is illustrated, just by way of example, in
As shown in particular in the two
The adjustment of the reciprocal distance in axial direction (i.e. parallel to the axis A-A) of the two disc-shaped cutting blades 37 and 39 may be obtained with any suitable elongation mechanism or system. In
More in particular, in the embodiment of
Devices for adjusting the angular offset of the two disc-shaped cutting blades 37 and 39 may be also provided. For example, each of the two disc-shaped cutting blades 37, 39 can be supported on a slide mounted on a respective arm 33, 35, movable along a guide centered with respect to the axis A-A. The slide can be positioned in the suitable position along the guide, and locked there, for example by means of a fastening screw system.
With the cutting machine 1 describe above it is possible to perform two cuts of the log 7 for every rotation of the rotating unit 25. As the two disc-shaped cutting blades 37 and 39 are offset by an angle smaller than 180°, there is a relatively long time between a cutting operation and the following one, during which both the disc-shaped cutting blades 37 and 39 are clear of the log 7, and during which it is possible to move the log 7 forward to position it correctly for the following cut. This time, longer than that available in the prior art cutting machines, where the disc-shaped cutting blades are offset by 180° from each other around the rotation axis of the rotating unit, allows to make the machine operate with lower accelerations of the logs 7 in the feed path 5, i.e. it allows to rotate the rotating unit 25 at a greater speed without the need for using too high accelerations for moving forward the logs between two consecutive cuts. As more time is available between two pairs of cuts, it is possible to increase the rotation speed of the rotating unit 25, thus increasing the machine productivity without increasing the mechanical stress and without accelerating the logs 7 too much.
As the two disc-shaped cutting blades 37 and 39 are angularly offset with respect to each other, they penetrate at different times through each log 7, which advance along the channels 11 of the feed path 5. In this way, at every rotation of the rotating unit 25 two cuts of each log 7 are performed, that are however temporarily staggered, so that there is no excessive compression of the product during cutting.
According to some embodiments, the angular offset (angle α) between the two disc-shaped cutting blades 37 and 39 may be such that the second disc-shaped cutting blade (for example the disc-shaped cutting blade 39) penetrates the log 7 when the first disc-shaped cutting blade (for example the disc-shaped cutting blade 37) has completely exited the log 7. In other embodiments, the angular offset can be such that both disc-shaped cutting blades 37 and 39 are engaged in the same log 7 for a given time interval and, therefore, for a given cutting angle. However, the angular offset can be chosen so that the second disc-shaped cutting blade penetrates the tubular winding core of the respective log 7 after the first disc-shaped cutting blade has exited from it. In this way the tubular winding core is not pressed in axial direction by both the disc-shaped cutting blades 37 and 39 contemporaneously.
In
The sequence of
In view of the above description it is understood that, thanks to the particular configuration of the cutting machine 1, with the two disc-shaped cutting blades 37 and 39 axially and angularly offset, it is possible to perform the cut quickly, with high productivity, significantly reducing the compression stress of the material of which the product is made (in this specific case the logs 7) due to the effect of the thickness of the disc-shaped cutting blades penetrating it.
As mentioned above, when the cutting machine 1 has a plurality of parallel channels 11, the logs 7 to be cut can be moved along the single channels 11 in staggered manner, so that when the two disc-shaped cutting blades 37 and 39 have finished cutting the first log met along the circular forward trajectories, and they are cutting the following logs, the first log 7 can start moving forward so as to be positioned correctly for the subsequent cut. Substantially, the forward movement of the logs 7 in the feed channels 11 occurs, in this case, in a sequential and temporarily staggered manner, starting the forward movement as quickly as possible, i.e. as the single log 7 is no more interested by the action of the disc-shaped cutting blades 37 and 39. In this way the time available for cutting the log 7 is increased. The offset forward movement of the logs 7 is possible, for example, by using the motors 19 separate, one for each feed channel 11.
Through the central control unit 21 it is possible to select the desired product so that the cutting machine is automatically configured to perform the desired cutting length. In particular, the axial offset between the disc-shaped cutting blades 37 and 39 can be automatically adjusted and, if necessary, also the angular offset (i.e. the angle α) around the axis A-A. Analogously, the holding members 71A, 71B, 71C take the reciprocal positions adequate for the right cutting length.
Whilst in the above description, it has been assumed that the logs 7 move forward in an intermittent way and the cutting head 23 has a fixed position in the direction of the rotation axis A-A, in other embodiments the cutting head 23 may be provided with a reciprocating movement parallel to the feeding direction of the logs 7 to be cut along the feed path 5. In this case, the cut can be performed whilst the log(s) 7 continue moving forward, if necessary at reduced speed, along the feed path 5. During cutting, i.e. whilst the disc-shaped cutting blades 37, 39 are engaged in the log(s) 7 to be cut, the cutting head 23 moves forward at the same speed as the logs 7. In the time interval during which the disc-shaped cutting blades 37 and 39 do not interact with the log(s) 7 to be cut, the cutting head 23 can move backward returning to an initial position. In this way, the cut of the logs 7 is faster and more uniform, as the logs are never completely stopped. Cutting machines provided with this function are known and disclosed in some prior art documents cited in the introductory part of the present description.
Number | Date | Country | Kind |
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102017000081298 | Jul 2017 | IT | national |
Filing Document | Filing Date | Country | Kind |
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PCT/IB2018/055230 | 7/16/2018 | WO | 00 |