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(11) | EP 2 813 331 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Apparatus for cutting cardboard panels into strips |
| (57) The present invention relates to an apparatus for cutting cardboard panels into strips
to be used in the packaging sector. In particular the invention is related to an apparatus
which makes it possible to cut any corrugated cardboard panel into strips of any dimension
in a precise and efficient manner, avoiding at the same time the production of dross
and dust residues which collect into the corrugations of the same panels. The apparatus
comprises a system (2) for moving one or more said panels (P) along a horizontal plane,
a supporting structure (4) for one or more blades (3) and a motor (6) for operating
said blades, wherein said supporting structure (4) of the blades (3) comprises a frame
(4) bearing blades mounted onto a supporting structure (5) for allowing its moving
alternatively forwards and backwards, preferably along an inclined plane with respect
to the horizontal plane of the moving system (2) of said panels so that a plurality
of blades (3) of cutter type can make an inclined cut with respect to the horizontal
plane surface of the panel (P).
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TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to an apparatus for cutting cardboard panels into strips to be used in the packaging sector. In particular, the invention is related to an apparatus which makes it possible to cut any corrugated cardboard panel into strips of any dimension in a precise and efficient manner, avoiding at the same time the production of dross and dust residues which collect into the corrugations of the same panels.
PRIOR ART TECHNIQUE
[0002] In the packaging sector, it has long been known the use of the so-called "filling" materials which can ensure the integrity of the packaged item during the operations of moving the item to warehouses, during its loading, transport and unloading from vehicles. These materials are largely used in the furniture sector to protect pieces of furniture or parts of pieces of furniture such as furniture doors, doors, shelves, ledges, accessories and ornaments.
[0003] A widely used material is polystyrene in the form of pellets or strips or panels of various dimensions.
[0004] However, polystyrene needs differentiated disposal and absolutely it is not an eco-friendly material.
[0005] Those who operate in the large-scale retail trade have long been requiring the suppliers to replace polystyrene with eco-friendly materials.
[0006] The eco-friendly material par excellence is cardboard. In fact, thanks to its corrugated structure and to its natural origin, cardboard meets both strength requirements necessary to ensure a very good functionality as a filler, and environmental requirements as it clearly derives from vegetal fibers.
[0007] The methods known at present for making strips from corrugated cardboard panels consist in using apparatuses provided with rotating or band blades. The use of such blades though involves two important technical problems.
[0008] First of all, the blades are made with teeth which, while cutting, produce a product dross of 2-4 mm. Such dross is little important if singularly considered, but it becomes a great waste of material if, as it normally occurs, a panel of great dimensions is cut simultaneously by numerous blades to produce several strips at the same time. In fact, it is to keep in mind that mainly in the production of thin strips (15-20 mm thickness) dross highly affects the finished product yield margins which are extremely reduced with respect to the cost of the raw material.
[0009] Moreover, dross, due to the blade teeth shape, turns into a great amount of dust which wedges and gathers into the corrugations of the strips. It is, therefore, necessary to make the strips undergo a further processing by means of machinery which can ensure a deep cleaning of the corrugations through blowing or suction of dusts. In fact, cleaning is fundamental in order to provide a correct use of the strips and without any inconveniences; such as no dust both in the packaging station and inside the package itself; no scratches caused by the same dust on particularly delicate items, as well as no need for carefully cleaning the items from the same dust.
SUMMARY OF THE INVENTION
[0010] The technical problem at the basis of the present invention is therefore that of providing an apparatus capable of avoiding dross production and its transformation into dust gathering in the corrugations of the cardboard strips for packaging.
[0011] Such problem is solved by an apparatus provided with a system for cutting corrugated cardboard panels made so as to obtain strips of any dimension, and from any type of corrugated cardboard, basically without dross and dust inside the corrugations.
[0012] A first object of the invention is then an apparatus for cutting corrugated cardboard panels into strips.
BRIEF DESCRIPTION OF FIGURES
[0014] Further characteristics and advantages of the apparatus of the invention will become more apparent from the following description of a form of embodiment given for exemplification only but not limited to with reference to the following figures, wherein:
- figure 1 shows a schematic plan view of a plant for the production of corrugated cardboard strips according to the present invention;
- figure 2 shows a schematic perspective view of a device for moving forward corrugated panels of the apparatus for cutting corrugated cardboard panels according to the invention;
- figure 3 shows a perspective view of the apparatus for cutting corrugated cardboard panels according to the invention;
- figure 4 shows a perspective view of a particular of the apparatus of figure 3;
- figure 5 shows a perspective view of a device for fixing blades, disassembled from the apparatus of figure 3;
- figure 6A and 6B show a front view and a side view of a blade of the apparatus of figure 3;
- figure 7 shows a perspective view of the cutting system of the apparatus of figure 3;
- figure 8 shows a schematic perspective side view of the cutting system of the apparatus of figure 3 in operating condition;
- figure 9 shows a perspective front view of a particular of the system of figure 8;
- figure 10 shows a perspective side view of the cutting system of figure 8 with a device for moving away the cut strips.
DETAILED DESCRIPTION OF THE INVENTION
[0015] In figure 1, it is shown a schematic plan view of a plant 100 for making strips of corrugated cardboard. The plant 100 comprises an apparatus 1 for cutting strips of corrugated cardboard provided with an entrance I of a corrugated cardboard panel and an exit O of corrugated cardboard strips after the transit of the panel in the apparatus 1.
[0016] The apparatus 1, in its turn, comprises a moving system 2 (shown in figure 2) for one or more corrugated cardboard panels P, a plurality of blades 3 of the cutter type mounted on a frame 4, a supporting structure 5 of said frame 4 of the blades 3 (figure 3).
[0017] In particular, as shown in figure 2, the moving system comprises a couple of conveyor belts 2 apt at receiving a corrugated cardboard panel P in the entrance area I of the apparatus 1 and move it forward, that is in the opposed direction with respect to the entrance I, compacting it sandwich-like on both its two faces.
[0018] In accordance with a first aspect of the invention, the frame 4 (figure 3) is a supporting structure which advantageously carries cutter type blades 3 and is made of a sort of castle comprising two horizontal and parallel crossbeams 41 A and 41 B and connected one to the other to the respective ends by means of corresponding uprights 42. In this way, it is formed a sort of rectangle defining a space occupied by the blade guides, as later described.
[0019] Advantageously, it is to note that the frame 4, in turn, is slidably mounted onto the supporting structure 5. The supporting structure 5, in fact, comprises a bridge 51 integral with a base 52, the latter anchored to the ground, preferably onto a concrete pour. On the base 52 it is fixed an electric motor 6 connected to an eccentric shaft 7 through a conventional transmission (not shown). The ends of the eccentric shaft 7 are connected to a connecting rod 8, which is then fixed to said upright 42 of the frame 4. In particular, the frame 4 is slidably mounted onto guides 53 fixed on the uprights of the bridge 51 so as to allow the moving forwards and backwards of the same frame towards one direction or towards the opposite direction. Surprisingly, it has been found that the use of the cutter type moved by means of the above said frame has made it possible to considerably reduce the above said problem of dross and of dust entering the cardboard corrugations.
[0020] In accordance with a preferred embodiment of the invention (as well shown in figures 8 and 10), the frame 4 is mounted onto said supporting structure 5 in an inclined position with respect to its base 52 (shown in figure 3). Consequently, the movement forwards and backwards towards alternate opposite directions advantageously indeed occurs on an inclined plane with respect to the base. In other words, the frame 4 moves on a plane which is inclined with respect to the moving plane of the panel P, as later explained in detail. It has been seen that the blade inclination makes it possible to further reduce the amount of dross produced so as to basically eliminate it, as well as the problem of dust in the corrugations.
[0021] Preferably, the frame 4 is inclined of an angle comprised between 30° and 60° with respect to the moving plane of the panel P. In fact, following experimentations it has been found that this inclination degree allows the best cutting angle which reduces the stress and wearing out the blades 3 undergo and, therefore, it is advantageously increased their operating life.
[0022] With reference to figure 4, it is shown a fixing device 10 of the blades 3 to the frame 4. In particular, the device 10 comprises a first fixing element 11 and a second fixing element 12.
[0023] The first fixing element 11 comprises a first fixing portion 111 to the upper crossbeam 41 A of the frame 4 and a second portion 112 for engagement with a first end of a blade 3, as later described. Preferably, the first portion 111 is a longitudinal piece provided with two holes 113 for fixing with screws and nuts (not shown) to said crossbeam 41 A. The second portion 112 is T connected to the first portion and comprises a pin 114 for engagement with said first end of the blade 3. Preferably, this pin 114 can be placed in at least two not aligned positions with respect to the longitudinal extension of said second portion.
[0024] The second element 12 is T-shaped basically similar to that of the first element 11, that is, it comprises a first portion 121 for fixing to the lower crossbeam 41 B and a second portion 122 for engagement with a second end of the blade 3. Preferably, the first portion 121 is provided with two through holes 123 for fixing to said crossbeam 41 B by means of screws and nuts. Further, it is preferably provided with a further hole engaged by a tensioning element 15 of the blade 3. The second portion 122 is longitudinally crossed by an inner groove 124 connected to said further hole.
[0025] The tensioning element has a central body 151 apt at engaging said inner groove 124, a first end 152 protruding from said second portion 122 of the second element 12 and a second end 153 protruding from said first portion 121 still of the said second element 12. The first end 152 has a flat head carrying a pin 154 for connecting to a second end of the blade 3. Preferably, said flat head has a surface extended enough so as to allow to place the pin 154 in at least two different not aligned positions with respect to the longitudinal extension of said tensioning element.
[0026] On the contrary, the second end 153 comprises a threaded portion 155 whereon a nut 156 is screwed or unscrewed which makes it possible to adjust the blade 3 tensioning. In fact, the nut screwing causes the tensioning element to move, and therefore also of the first end 152 connected to the blade 3, in the traction direction of the same blade. On the contrary, unscrewing causes the traction release.
[0027] Preferably, between the nut 156 and the first portion 121 of the second element 12 of the fixing device 10 there is interposed a sleeve 157 provided with an elastic element, such as a spring, having the function of ensuring the correct tensioning of the blade and of absorbing possible side or transverse excess loads.
[0028] In accordance with a preferred form of embodiment of the invention, the fixing device 10 of the blades 3 comprises guiding means apt at keeping each blade along a single straight line during the cutting operation.
[0029] To this purpose, the apparatus 1 also comprises a supporting structure 9 for the above said guiding elements 13, 14 of blades 3. This structure 9 (figure 3) is preferably composed of a first element 91 and of a second element 92. The first element 91 is a sort of table, fixed to the ground or to the base 52, whereon it is made to slide the panel P coming from the entrance I of the apparatus 1. One edge 911 of such table is placed in the space defined by the frame 4 and has a housing seat 912 for the first element 13 of said guiding means. Preferably, said seat is shaped step-like, as better shown in figure 5.
[0030] The second element 92 is a sort of bar extending horizontally between the uprights of the bridge 52 and fixed to them. In particular, the bar is positioned on the upper part and at a certain distance from the edge 911 of the first element 91. In this position, the bar 92 and the edge 911 are basically aligned along the vertical (axis) so as to practically be in the space defined by the frame 4. Moreover, this bar 92 comprises a track 913 (shown in figure 5) whereon the second element 14 of said guiding elements are mounted. Preferably, each end of the bar 92 is connected to the uprights of the bridge 51 by means of a sliding guide (not shown) operated by a manual or automated mechanism in order to make it possible its moving away or close with respect to the edge 911 of the table 91 of the structure 9. Such mechanism is, for example, formed by a screw 914 manually operated by a rod 915 (figure 5).
[0031] It is to note that the just described mechanism makes it possible to keep the panel pressed while cutting so as to avoid movements which can cause an imperfect cut (for example not rectilinear) and/or formation of folds (Figure 8).
[0032] As shown in figure 4, the guiding elements are, for example, a first 13 and a second 14 guiding element. The first guiding element 13 is provided with an anchoring portion 131 to the edge 911 of the table 91 of the support 9 of the guiding elements and a guiding portion 132 of the blade 3. Preferably, the anchoring portion 131 comprises a groove 133 for the engagement to a corner (not shown) of the seat 911 of the edge 91 and clamping elements 134 to anchor said first guiding element on said edge 91. These clamping elements 134 are formed by, for example, a plate provided with an engaging tooth, mounted on a screw provided with a nut so as to make it possible to adjust the plate blocking on a further corner (not shown) of the edge 91.
[0033] Preferably, the guiding portion 132 consists of two plates fixed to the anchoring portion 131 so as to define a groove 135 which is slidably engaged by a blade 3.
[0034] Similarly, the second guiding element 14 comprises an anchoring portion 141 to the bar 92 of the supporting structure 9 of the guiding means and a guiding portion 142 of a blade 3. Preferably, the anchoring portion 141 comprises a groove 143 for engagement with a corner (not shown) of the bar 92 and clamping means 144 for anchoring said second guiding element onto said bar 92. These clamping means 144 consist of, for example, a plate, provided with a engaging tooth, mounted on a screw provided with a nut so as to make it possible to adjust the plate blocking on a further corner (not shown) of the bar 92.
[0035] Preferably, the guiding portion 142 consists of two plates fixed to the anchoring portion 141 so as to define a groove 145 which is slidably engaged by a blade 3.
[0036] With reference to figures 6A and 6B, the reference number 3 is referred to a blade of cutter type used in the apparatus 1 according to the present invention. In particular, the cutter blade 3 is a metal band having a longitudinal edge 31 whose transverse profile has a gradual thinning up ending in a point (figure 6B). Further, longitudinally, said profile 31 has an undulating form with pointed apexes of the flutes. Preferably, the bending radius of the flutes is comprised between 10 mm and 50 mm and the apex height is comprised between 3 mm and 5 mm. The maximum thickness of the blades is not higher than 0.9 mm, preferably it is between 0.5 mm and 0.8 mm. It results that the dross produced is practically reduced to zero.
[0037] Such blades are preferably made of metal, preferably steel having a surface hardening treatment. It has been seen that this particular combination of the cutter blade characteristics makes it possible to fully reduce the formation of dust while cutting and at the same time, its wearing out with an operation life of more than 40 hours. Further, each of the blade ends has a hole 32 for engaging respectively with the pin 114 and 154 of the first 11 and second 12 fixing element of the blade to the frame 4 (figure 4).
[0038] In accordance with a preferred embodiment of the invention, the blades 3 are mounted on the frame 4 so as not to be aligned, in other words staged with respect to the cutting plane. In particular as shown in the detail of figure 7, adjacent blades are positioned onto two parallel but not aligned planes, one lower and the other higher, that is one nearer to the base 52 of the supporting structure 5 of the frame 4 and the other farther. This particular arrangement is obtained thanks to the different anchoring position of the blade 3 ends respectively on the first element 11 and the second element 12 of the fixing device 10 to the frame 4, thanks to the possibility of varying the position of pins 114 and 154 with respect to the longitudinal extension of the respective first element 11 and second element 12.
[0039] Moreover, in accordance with the present invention the plant 100 preferably comprises a couple of motored conveyor belts 16 (figure 10) placed in the proximity of the exit O of the apparatus 1 for cutting strips. These rolls 16 have the function of taking the just cut strips and, keeping them "sandwich" pressed, moving them forward to an unloading area of the plant 100. Hence, advantageously, the strips exiting the apparatus 1 remain compact and do not undergo folds.
[0040] In accordance with a second object of the invention it will now be described a method for cutting corrugated cardboard strips.
[0041] Such method comprises the steps of:
- providing one or more corrugated cardboard panels possibly stacked;
- moving forward said one or more panels onto a horizontal plane towards a plurality of blades keeping them "sandwich" pressed,
- moving a plurality of cutter blades parallel each other alternatively in one direction and in the opposite one;
- carrying out a cut of said panel into strips.
[0042] In accordance with a particularly preferred embodiment of the invention, the moving step occurs forwards and backwards along a plane inclined with respect to the horizontal moving forward plane of said panels.
[0043] In particular, the corrugated cardboards provided can be of any shape, length, breadth and thickness traditionally on the market. For example, they can be multilayered cardboards with a minimum thickness of 3 mm. The structure of the corrugations can be any of the known in the field, such as open flute, or for all kinds of available flutes: flute B (total cardboard thickness 3.0 mm), flute C (total cardboard 4.0 mm), flute EB (total cardboard 4.5 mm), flute BC (total cardboard 6.2 mm), flute CC (total cardboard 8.0 mm), flute AA (total cardboard 8.5 mm), as well as all undulating types of cardboard, 1, 2 or 3 fluted walls according to the FEFCO international classification. For example their breadth can vary from a minimum of 100 mm up to 1250 mm, while the height of a single cardboard or of a pack of cardboards can be for example up to a maximum of 150 mm.
[0044] The moving forward step is carried out keeping the cardboard sandwich pressed, such as shown in figure 2. The moving forward speed is comprised between 0.5 m per minute and 5 m per minute.
[0045] The plurality of cutter blades is moved according to the above said alternate movement at a frequency comprised between 10 swing/second and 30 swing/second. Further, according to the preferred embodiment, as previously described, the inclination of the blades, and thus of the cut, with respect to the horizontal plane of the corrugated cardboard panel is comprised between 30° and 60°, as shown in figure 8.
[0046] As previously described, the cutting step is preferably carried out positioning adjacent blades staged and separated one to the other in a variable manner along a longitudinal line, as shown in figure 9.
[0047] The method preferably also comprises a collecting step of the cut strips by moving forward and, at the same time, sandwich pressing the strips exiting the cutting step. Such collecting step is preferably carried out, as shown in figure 10, by means of a motored conveyor belts.
[0048] From the foregoing it is apparent that the inconveniences of the known art have been solved and important advantages have been achieved.
[0049] First of all, the apparatus and the method according to the invention make it possible to fully reduce the dross produced with traditional apparatuses provided with rotating or band blades and hence the waste of material. This entails a great saving in terms of material. At the same time, it is avoided the consequent cleaning of the dust which gathers in the corrugations of the strips.
[0050] The pitch between the single blades is variable thanks to the possibility of mounting the respective supporting devices singularly along corresponding longitudinal structures. In this way, it is possible to contemporarily make strips of different width on the same panel. It is clear that this solution allows the greatest flexibility of the machine tooling and the optimization of the panel exploitation.
[0051] The frame 4 of the blades makes it possible to adjust their inclination with respect to the horizontal plane so as to adapt the blade cutting capacity to the corrugated panel structure.
[0052] The possibility of staging the blades one from the other makes it possible to improve their penetrating effect on the pack of panels, that is to reduce the load generated on the blades as they are not contemporarily involved in the incoming panel to be cut.
[0053] It is possible to independently adjust the tensioning of each blade thanks to the particular make of the fixing device 10 of the blades.
[0055] Through the adjustment of the distance between the first element 13 and the second element 14 of the guiding means of the blades it is possible to adjust the pressure in correspondence with the cutting point of the panel so as to avoid its moving which can hinder the precision of the same cut. Moreover, this adjustment allows to adapt the cutting method to any thickness of the cardboard or of more stacked panels to be cut.
[0056] It can now be seen that according to the thickness, the number and the corrugation structure of the panels, the apparatus is capable of independently adjusting the moving forward speed of the panel to be cut, the swing frequency of the blades, the pitch of the blades, the distance between the first guiding element 13 and the second guiding element 14, the blade tensioning, all in order to optimize the cutting method. Practically, if the thickness and/or the corrugation structure are respectively thin and wide then the moving forward speed will be high and the swing frequency of the blades will be low. The contrary will occur when the thickness and/or the corrugation structure will be respectively high and narrow.
[0057] It is to bear in mind that many variants can be made to the apparatus and method of the present invention without exiting its protection field as defined by the appended claims.
[0058] For example, the force for moving the frame 4 of the blades can be obtained by non electric motors but internal combustion motors, or with mechanical vibration systems, ultrasound, magnetic induction motors, etc.
[0059] The adjustment of the distance between the guiding elements 13 and 14 can occur electromechanically rather than manually.
[0060] A control and command panel of the members of the device 10 can control and operate singularly said members in order to adjust their operation according to the specific cutting conditions. For example, operating and controlling the synchronous moving forward speed of the corrugated cardboard panel incoming and exiting the cutting apparatus 1, operating and controlling the swing frequency of the frame independently from the moving forward speed of the cardboard.
[0061] The guiding elements 13 and 14 can have the guiding portion made en bloc milled so as to obtain the housing groove of the blade 3. Moreover, these same guiding elements can be fixed to the respective supports by means of traditional screws and nuts rather than plates with crimping teeth.
[0062] The dimensions and the materials of the devices and of the elements of the apparatus according to the present invention can vary depending on particular requirements or preferences. For example, the thickness of each component of the fixing device 10 of the blades can be reduced to the purpose of mounting a greater number of blades 3 on the frame 4 and of being able to cut out of a single panel both a greater number of strips and a lower width for each strip.
[0063] The plant 100 can further comprise a station for manually or automatically loading the cardboards to be cut for example taking them from a storage pallet. The loading can be automated so as to select the type and number of panels to load both side-by-side and stacked.
[0064] Besides the loading station, it can be provided a station for the transverse sectioning of the panel before cutting it into strips in order to determine their final length.
[0065] At the exit of the strips cut by the apparatus 1 there can be a machine for collecting and stacking the strips at the side of the plant in order to carry out their storage.
1. Apparatus (1) for cutting corrugated cardboard panels (P), comprising a moving system
(2) of one or more of said panels (P) along a horizontal plane, a supporting structure
(4) for one or more cutting tools (3) and a motor (6) for moving said one or more
cutting tools, characterized in that said supporting structure (4) for said cutting tool (3) comprises a frame (4) for
bearing blades, which frame is mounted onto a supporting structure (5) to allow the
alternate backwards and forwards moving of said frame along an plane inclined with
respect to the horizontal plane of the system (2) for moving said panels so that a
plurality of blades (3) of cutter type carries out a cut inclined with respect to
the horizontal plane surface of the panel (P).
2. Apparatus (1) according to claim 1, wherein said moving system (2) comprises a couple
of conveyor belts adapted to carry between them one or more of said panels (P) while
exercising a compacting pressure.
3. Apparatus (1) according to claim 1 o 2, wherein said frame (4) comprises two parallel
and horizontal cross-beams (41 A, 41 B), connected to the respective ends by means
of vertically inclined uprights (42), said plurality of blades (3) being mounted between
said two cross-beams by means of a fixing device (10) so that said blades are vertically
inclined and parallel to each other.
4. Apparatus (1) according to claim 3, wherein said fixing device (10) comprises a first
element (11) having a first portion (111) for fixing to the upper cross-beam (41 A)
of the frame (4) and a second portion (112) for engagement with a first end of a blade
(3), and a second element (12) having a first portion (121) for fixing to the lower
cross-beam (41 B) of the frame (4) and a second portion (122) for engagement with
a second end of said blade (3).
5. Apparatus (1) according to claim 4, wherein said second fixing element (12) further
comprises a tensioning element (15) of a blade (3).
6. Apparatus (1) according to any one of claims 3 to 5, wherein said structure (5) for
supporting said frame (4) comprises a bridge (51) provided with uprights onto which
guides (53) allowing said movement of the frame are fixed.
7. Apparatus (1) according to any one of claims 1 a 6, wherein said frame (4) moves onto
said supporting structure (5) along a plane inclined of 30°- 60°with respect to the
horizontal moving plane of the panel (P).
8. Apparatus (1) according to any one of claims 1 to 5, further comprising a supporting
structure (9) of guiding means (13, 14), said means being adapted to maintain each
blade (3) along a straight line during the cutting.
9. Apparatus (1) according to claim 8, wherein said supporting structure (9) comprises
a first element (91) for supporting a first guiding element (13) and a second element
(92) for supporting a second guiding element (14), the distance between said first
(91) and second (92) supporting elements being adjustable to bring close or away said
first (13) and second (14) guiding elements.
10. Apparatus (1) according to claim 9, wherein each of said first (13) and second (14)
guiding elements comprises an anchoring portion (131; 141) respectively for said second
supporting element (92) and first supporting element (91), and a guiding portion (132;
142) provided with a groove (135; 145) for a sliding engagement of said blade (3).
11. Method for cutting corrugated cardboard panels, comprising the steps of:
a) providing one or more corrugated cardboard panels eventually stacked;
b) moving forward said one or more panels onto a horizontal plane towards a plurality of cutter blades while keeping said one or more panels "sandwich" pressed;
c) moving a plurality of cutter blades parallel each other, alternately backwards and forwards along a plane inclined with respect to the horizontal moving forward plane of the panels;
d) carrying out a cut of said panel into strips.
12. Method according to claim 11, wherein the moving forward step is carried out keeping
the cardboard sandwich pressed, the forward speed is comprised between 0,5 m per minute
and 5 m per minute, the plurality of cutter blades is moved according to said alternate
movement at a frequency comprised between 10 swing/second and 30 swing/second, the
inclination of the blades, and thus of the cut, with respect to the horizontal plane
of the corrugated cardboard panel is comprised between 30° e 60°, the cutting step
is preferably carried out positioning adjacent blades staged and separated one to
the other in a variable manner along a longitudinal cutting line.