Machine sander with improved sanding unit, a cooling unit, and method of operating the sanding machine

Abstract

The present invention relates to a sander machine (1) for sanding a piece (P), such as panels made of wood, plastic, fiberglass, and the like, comprising: a frame (11) having an entrance (111) for the entry of a piece (P) to be sanded, and an exit (112) for the exit of the sanded piece (P), wherein the piece (P) is moved from said entrance (111) to said exit (112) along an advancement direction (A); a main sanding group (2) positioned between said entrance (111) and said exit (112) for sanding the piece (P); and a transverse sanding group (3) positioned between said entrance (111) and said exit (112), The present invention also relates to a transverse sanding group (3) and a method (100) for cooling an abrasive belt (33) in a sander machine (1).

Description

[0001] The present invention relates to a sanding machine with an abrasive belt cooling unit that uses air to cool the abrasive belt during operation.Field of invention

[0002] More specifically, the invention concerns a cooling unit for machines of the aforementioned type, and in particular for sanding machines with transverse sanding, designed and manufactured particularly to limit the heating of the sanding belt, but which can be used in any case, in which it is necessary to selectively cool working areas.

[0003] In the following, the description will be directed to machines for the transverse sanding of wooden panels, but it is clear that the same should not be considered limited to this specific use.Prior art

[0004] Machines for sanding large-surface panels are widely used in the wood and composite materials industries. In particular, cross-cut sanders, which operate perpendicular to the panel's advancement direction, are used to achieve high-quality surface finishes.

[0005] During the sanding machining, the friction between the sanding belt and the panel surface generates considerable heat. This can cause several problems, especially when working with materials sensitive to high temperatures, such as melamine or painted panels. Excessive heating can compromise the quality of the surface finish or even damage the material itself.

[0006] To mitigate these undesired effects, several solutions have been developed.

[0007] A first known solution is based on the use of antistatic abrasive belts, which helps prevent dust accumulation, thus reducing unnecessary abrasion.

[0008] Additionally, it's common practice to reduce belt speed and working pressure to limit heat generation. However, these solutions often result in a decrease in sanding performance.

[0009] In some cases, cross-sanding is used, using belts rotating in opposite directions. This approach distributes the workload between the belts, but can lead to uneven results when one belt becomes clogged with dust and works less efficiently than the other.

[0010] Despite these measures, temperature control during the sanding of large panels remains a significant technical challenge in the industry. The search for innovative solutions that can ensure effective cooling without compromising the quality and efficiency of the sanding process is therefore of great industrial interest.

[0011] Heat accumulation remains particularly problematic for large panels, with working widths of the order of 3700 mm, where current solutions prove insufficient.

[0012] These issues highlight the need to develop an innovative cooling system that can ensure effective heat dissipation without compromising the efficiency and quality of the sanding machining.Purpose of the invention

[0013] In light of the above, it is therefore the aim of the present invention to provide an innovative cooling system for cross sanders that allows for effective heat dissipation during the machining of large panels.

[0014] Another aim of the invention is to allow the maintenance of high working speeds and optimal pressures without compromising the quality of the sanding, thus overcoming the limitations of traditional methods.

[0015] It is also the aim of the present invention to ensure precise temperature control during the sanding machining, which is particularly important for heat-sensitive materials such as melamine or painted panels.

[0016] It is a further aim of the present invention to improve the overall efficiency and versatility of the cross-sanding machining, allowing for greater productivity in the machining of different types of panels.

[0017] A further aim of the invention is to provide an air recirculation system that effectively integrates the cooling of the unit and the control of the dust produced by the machining, improving both the quality of the finish and the working environment.Object of the invention

[0018] It is specific object of the present invention a sander machine for sanding a piece, such as panels made of wood, plastic, fiberglass, and the like, comprising: a frame having an entrance for the entry of a piece to be sanded, and an exit for the exit of the sanded piece, wherein the piece is moved from said entrance to said exit along an advancement direction; a main sanding group positioned between said entrance and said exit for sanding the piece; and a transverse sanding group positioned between said entrance and said exit, and comprising an abrasive belt, having a first abrasive face and a second face, opposite said first face, movement means for said abrasive belt, capable of moving said abrasive belt along a dragging direction at a dragging speed to perform the sanding of said piece, wherein said dragging direction is substantially perpendicular or oblique with respect to said advancement direction; and a lamellar belt having a plurality of lamellae, arranged so that said lamellae are in contact with said second face of said abrasive belt; wherein said sander machine is characterized in that said transverse sanding group comprises a cooling unit having an air source for supplying air of a cooling air flow, one or more openings or nozzles to direct said cooling air flow from said air source onto said lamellar belt, wherein said cooling air flow passes through the lamellae of said lamellar belt, so as to pass between said abrasive belt and said lamellar belt.

[0019] Always according to the invention, the dragging speed of said abrasive belt and the air speed of the cooling air flow may be coordinated so that the relative direction of the cooling air flow is substantially parallel to the inclination direction of the lamellae of said lamellar belt.

[0020] Still according to the invention, said cooling unit may comprise a plurality of said openings or nozzles distributed transversely with respect to the advancement direction of the piece.

[0021] Advantageously according to the invention, said machine may comprise a reading barrier, positioned at said entrance, comprising a plurality of the lamellae arranged adjacent to each other, transversely with respect to said advancement direction of the piece, wherein said reading barrier is adapted to detect the length and / or width of the piece to be sanded entering through said entrance; and the nozzles corresponding to the flaps lifted following the introduction of a piece to be sanded may be activated.

[0022] Further according to the invention, said air source may be an electric fan, and said cooling unit may comprise one or more ducts for the supply of cooling air, which fluid-dynamically connect said air source to said openings or nozzles.

[0023] Further according to the invention, said main sanding group may comprise an upper sanding roller arranged transversely with respect to said advancement direction of the piece, a return roller positioned above said sanding roller, a longitudinal sanding belt, positioned between said upper sanding roller and said return roller, and a lower roller positioned below said upper sanding roller, facing said upper sanding roller; and said transverse sanding group may be positioned downstream of said main sanding group.

[0024] Always according to the invention, said cooling unit may comprise collecting means for the heated air flow from said abrasive belt, positioned facing said openings or nozzles on the opposite side of said openings or nozzles with respect to said abrasive belt.

[0025] Still according to the invention, said collecting means may comprise a plurality of hoods, arranged adjacent to each other, and one or more ducts for the extraction of hot air for the extraction of air.

[0026] Further according to the invention, said sander machine may comprise a buffer roller to apply pressure on the panel to hold it in place during the sanding stages.

[0027] It is further object of the present invention a transverse sanding group comprising: an abrasive belt having a first abrasive face and a second face, opposite said first face; movement means for said abrasive belt, capable of moving said abrasive belt along a dragging direction at a dragging speed to perform the sanding of said piece, wherein said dragging direction is substantially perpendicular or oblique to said advancement direction; and a lamellar belt having a plurality of lamellae, arranged so that said lamellae are coupled to said second face of said abrasive belt; characterized in that it comprises a cooling unit having an air source for supplying air of a cooling air flow, one or more openings or nozzles to direct said cooling air flow from said air source onto said lamellar belt, wherein said cooling air flow passes through the lamellae of said lamellar belt, so as to pass between said abrasive belt and said lamellar belt.

[0028] Always according to the invention, the dragging speed of said abrasive belt, and the air speed of the cooling air flow may be coordinated so that the relative direction of the cooling air flow is substantially parallel to the inclination direction of said lamellae.

[0029] Still according to the invention, said cooling unit may comprise a plurality of openings or nozzles distributed transversely with respect to the advancement direction of the piece.

[0030] Advantageously according to the invention, said air source may be an electric fan, and said cooling unit may comprise one or more ducts for the supply of cooling air, which fluid-dynamically connect said air source to said openings or nozzles.

[0031] Further according to the invention, said cooling unit may comprise collecting means for the heated air flow from said abrasive belt, positioned facing said nozzles on the opposite side of said nozzles with respect to said abrasive belt, wherein said collecting means comprise a plurality of hoods, arranged adjacent to each other.

[0032] It is also object of the present invention a method for cooling an abrasive belt in a sander machine for a piece, comprising: advancing a piece through a sanding group of the sander machine; and moving an abrasive belt in a transverse direction relative to the advancement of the piece; characterized in that it comprises the steps of: directing a cooling air flow through a plurality of openings or nozzles onto a lamellar belt supporting the abrasive belt, wherein the cooling air passes through the lamellae of the lamellar belt between the abrasive belt and the lamellar belt.

[0033] Always according to the invention, said lamellar belt may comprise a plurality of lamellae arranged diagonally with respect to the advancement direction of the piece.

[0034] Still according to the invention, said method may comprise the step of coordinating the dragging speed of said abrasive belt and the speed of the cooling air flow, so that the relative direction of the cooling air is parallel to the inclination direction of said lamellae.

[0035] Advantageously according to the invention, said method may comprise the step of collecting the cooling air through a collection hood positioned on the opposite side of said openings or nozzles with respect to the abrasive belt.

[0036] Further according to the invention, said method may comprise the steps of: detecting the length and / or width of the piece by means of a reading barrier comprising a plurality of flaps; and activating said openings or nozzles corresponding to the flaps lifted by said reading barrier.Brief description of the figures

[0037] The present invention will be now described, for illustrative but not limitative purposes, according to its preferred embodiments, with particular reference to the figures of the enclosed drawings, wherein: figure 1 shows a rear perspective view of the overall view of a machine for the transverse sanding of panels; figure 2 shows a side section of the machine in figure 1; figure 3 shows a cooling unit according to the present invention, installed in the sanding machine according to figure 1; figure 4 shows the composition of the air flows on the abrasive belt; and figure 5 shows a flow diagram of a method for cooling an abrasive belt in a sanding machine according to the present invention. Detailed description

[0038] In the various figures, similar parts will be indicated with the same numerical references.

[0039] The present invention relates to a cross-belt sanding machine designed for processing large-sized panels, such as those made of wood, plastic, fiberglass and similar materials.

[0040] The machine features a cooling unit integrated into a transverse sanding unit. The cooling unit uses an air source to generate a flow of cooling air, which is directed onto the flap belt through one or more nozzles or openings. The cooling air flow passes through the lamellar belt's lamellae, thus cooling the abrasive belt during sanding operations. This approach dissipates the heat generated by friction between the abrasive belt and the surface of the panel or workpiece being sanded, reducing the risk of thermal damage to heat-sensitive materials and improving the overall quality of the sanding machining.

[0041] The lamellar belt may comprise a plurality of lamellae arranged diagonally with respect to the panel advancement direction. The speed of the abrasive belt and the speed of the cooling airflow can then be coordinated so that the relative direction of the cooling airflow is substantially parallel to the direction of the lamellar belt lamellae for each set abrasive belt speed. It is considered that that to maintain the relative direction of the airflow parallel to the lamellae, if the speed of the abrasive belt varies, the speed of the cooling airflow must be varied accordingly. This arrangement improves the cooling efficiency of the system, optimizing the sanding process at each set abrasive belt speed.

[0042] Referring now to figures 1 and 2, it is observed the sander machine 1, which essentially comprises a main sanding group 2 and a transverse sanding unit 3, for sanding panels P.

[0043] The sander machine 1 also comprises a frame 11, which provides structural support for the various components and parts of the machine 1 itself. Installed in the frame 11 is a transverse sanding unit 3, which is configured for transverse sanding operations.

[0044] The frame 11 has an inlet 111 for the entry of the P panel to be sanded, and an outlet 112 for the exit of the sanded P panel.

[0045] The sander machine 1, as mentioned, comprises the main sanding group 2, which comprises an upper sanding operating unit (roller or shoe or other operating unit) 21, arranged transversely with respect to the advancement direction a of the workpiece P.

[0046] Above the upper sanding roller 21 is positioned a return roller 22, which allows to guide and tension the longitudinal sanding belt 23, arranged between the upper sanding roller 21 and the return roller 22. The longitudinal sanding belt 23 is the main abrasive element of the main sanding group 2 and moves continuously during the machining of the panel P or workpiece in general.

[0047] Below the upper sanding roller 21, a lower roller 24 is positioned. This roller faces the upper sanding roller 21. The panel P passes above the lower roller 24 and under the upper sanding roller 21.

[0048] The panel is movable along the advancement direction A by means of a roller table comprising a plurality of motorized rollers 7, arranged transversely with respect to said advancement direction A.

[0049] In some embodiments, the main sanding group 2 may be positioned upstream of the transverse sanding group 3 in the panel machining path P. This arrangement may allow for an initial rough sanding followed by a finer, more precise finishing performed by the transverse sanding group 3.

[0050] Also referring to figure 3, the transverse sanding group 3 of the sander machine 1 can be observed in detail.

[0051] The transverse sanding group 3 comprises an abrasive belt 31, for sanding the workpiece P. In some aspects, the abrasive belt 31 may be an antistatic belt that discharges dust, thus improving the overall efficiency of the sanding process.

[0052] Below the abrasive belt 31, a lamellar belt 33 is positioned. The lamellar belt 33 may be composed of a plurality of lamellae 34, which in some embodiments are arranged diagonally on its surface.

[0053] In some cases, the lamellar belt 33 can be made of felt, a material that can provide a gradual impact to the workpiece during the sanding process.

[0054] The diagonal arrangement of the lamellae 331 can also create channels for the insertion and conveyance of cooling air. In fact, the abrasive belt 31 has a first abrasive face, intended to work the surface of the panel P to be sanded, and a second face, opposite to said first face. The lamellar belt 33 is arranged so that the lamellae 34 are coupled or associated during the machining with said second face of the abrasive belt 31. Therefore, the lamellae 331 of the lamellar belt 33 identify parallel and possibly oblique channels, delimited by the lamellae themselves, by the surface of the lamellar belt 33, on which the lamellae 34 are located, and by the second face (the non-abrasive one) of the abrasive belt 31, the function of which will be better defined below.

[0055] The transverse sanding unit 3 according to the invention comprises a cooling unit 4. Said cooling unit 4 comprises an air source 41, which generates a cooling air flow F c .

[0056] The air source 41, preferably an "air knife" or compressed air, may be positioned on top of the sander machine 1. The air knife is preferable because, coming from an electric fan, it is easier to adjust the feed back based on the speed of the sanding belt. In some cases, multiple air sources 41 may be distributed throughout the machine 1, suggesting a distributed air supply system.

[0057] The air source 41 may be connected to a cooling air supply duct 42. The cooling air supply duct 42 comprises a plurality of openings 43 or, as in the present case, nozzles, which are directed towards the abrasive belt 31 and the lamellar belt 33.

[0058] In some embodiments, the cooling air flow F c passes through the lamellae 331 of the lamellar belt 33, thus cooling the abrasive belt 31 during the sanding operation. In particular, the cooling air flow F c , exiting from the nozzles 43, passes through the aforementioned channels created by the lamellae 331 of the lamellar belt 33.

[0059] On the opposite side of the abrasive belt 31 with respect to the nozzles 43, collecting members 44 for the hot air or the heated air flow F h can be positioned. These collecting members 44 may be responsible for collecting the heated air flow F h , after the cooling air flow F c passed through the transverse sanding group 3.

[0060] In some cases, the collecting members 44 may be connected to extraction ducts 45, or removal ducts, which direct air away from the cooling unit 4. This arrangement can effectively manage the airflow after it has passed through the sanding area, potentially improving dust control and contributing to a better working environment.

[0061] In a preferred embodiment, the speed of the abrasive belt 31, which moves in a dragging direction L, orthogonal to the advancement direction A of the panel P, at a drag speed, and the speed of the cooling air flow can be coordinated, so that the relative direction of the cooling air flow is substantially perpendicular to the direction of movement of the abrasive belt 31, as seen schematically in figure 4.

[0062] In some embodiments the dragging direction L orthogonal to the advancement direction A of the panel P can also be oblique.

[0063] This arrangement improves the cooling efficiency of the system, allowing for high sanding speeds and optimal working pressures without compromising the quality of the workpiece.

[0064] The transverse sanding group 3 comprises a moving members 32 for moving the abrasive belt 31, which comprises pulleys and belts.

[0065] As mentioned, the cooling airflow F c can be directed parallel to the advancement direction A of the panel P. This can be achieved through the use of a cooling air supply duct 42, connected to the air source 41 positioned on the top of the frame 11.

[0066] The sander machine 1 may also comprise a pressure roller 6, positioned to apply pressure to the panels P during the sanding process. The pressure roller 6 may comprise multiple independent pressure sectors (not shown in the figures), which apply pressure to the workpiece P or panel being machined.

[0067] The sander machine 1 comprises a reading barrier 5 installed at the entrance 111 of the sander machine 1. The reading barrier 5 may comprise vertical flaps 51, which detect the dimensions of the incoming panels P, being moved by the passage of the panel P itself.

[0068] The reading barrier 5 is also capable of detecting both the length and width of the workpiece P being machined. The length is determined based on the time the flaps 51 remain raised as the panel P passes, knowing the advancement speed of the panel P.

[0069] The width of the P panel is determined based on the number of flaps 51 activated when the P panel passes.

[0070] This information can be used to adjust the operation of the sander machine 1 based on the size of the workpiece P. In some embodiments, the pressure roller 6 can be activated based on the detection of the reading barrier 5. For example, if the reading barrier 5 detects a workpiece of a certain size, the pressure roller 6 can adjust the pressure applied to the workpiece P accordingly. This can allow for more precise control over the sanding process, potentially resulting in a higher-quality finish on the workpiece P.

[0071] Furthermore, for energy saving or optimization, based on the length and width of the detected piece P, only some of the nozzles 43 of the cooling unit 4 can be activated, not necessarily all of them, and for an appropriate time interval.

[0072] The operation of the sander machine 1 described above is as follows.

[0073] Referring to figure 5, a method 100 for operating the sander machine 1 is illustrated. The method 100 may comprise several steps, which are described below.

[0074] The method 100 begins with step 110, which involves advancing a panel or workpiece P to be sanded through a sanding group 2 or 3 of the sander machine 1. This advance may be in a direction A orthogonal to the direction of movement of the abrasive belt 31 of the transverse sanding unit 3.

[0075] Subsequently, step 120 involves the movement of the abrasive belt 31 in the transverse direction L with respect to the advancement of the panel P. This movement is carried out by the movement members 32, which can also control the speed and direction of the abrasive belt 31.

[0076] In step 130, method 100 directs a flow of cooling air F c through the nozzles 43, on the lamellar belt 33. In this step the abrasive belt 31 cools.

[0077] More specifically, the cooling airflow F c may pass through the lamellae 331 of the lamellar belt 33, thus cooling the abrasive belt 31 during the sanding operation.

[0078] Step 140 then coordinates the speed of the abrasive belt 31 with the flow of cooling air F c , ensuring optimal cooling efficiency during the sanding operation. In some cases, the speed of the cooling air is coordinated with the speed of the abrasive belt 33 to keep the direction of the air parallel to the direction of the flaps of the lamellar belt 33. This arrangement can improve the overall cooling efficiency. In fact, in this way, the flow of the cooling air F c , passing through the channels identified in the lamellae 34, does not create turbulence, allowing for better cooling and more effective heat extraction.

[0079] The method 100 then comprises the step 150, which involves collecting cooling air through collection hoods 441. This step 150 manages the flow of heated air F h after the air has cooled the sanding belt 33. The collected air can then be removed from the sander machine 1 via extraction ducts 45.

[0080] The step 160 of the method 100 involves detecting the length and / or width of the workpiece P by means of the reading barrier 5. This step allows the machine 1 to adjust its operation based on the dimensions of the workpiece P.

[0081] The reading barrier 5 comprises flaps 51 that detect the dimensions of the incoming P panels.

[0082] The last step 170 activates the nozzles 43 corresponding to the raised strips of the reading barrier 5 from the passing panel P.

[0083] At this stage the cooling air is directed to the appropriate areas based on the detected dimensions of the P panel being machined.

[0084] The sander machine 1 may be designed to handle panels with large surface areas. For example, the sander machine 1 may be capable of machining panels P up to approximately 3700 mm in size. This capability may allow the sander machine 1 to be used in a variety of applications, including, but not limited to, sanding large furniture panels, construction panels, or any other panels with large surface areas requiring sanding.

[0085] The concepts, systems, and techniques described are not limited to use in the exemplary applications described herein (e.g., wood and composite panel manufacturing), but may be useful in essentially any application where efficient cooling during abrasive processing is desired.

[0086] While specific embodiments and applications of the present solution have been illustrated and described in connection with large-panel cross-sanding machines, it should be understood that the embodiments of the disclosure are not limited to the precise construction and compositions disclosed herein and that various modifications, changes, and variations may be apparent from the foregoing descriptions without departing from the spirit and scope of the disclosure as defined in the appended claims. The cooling system described herein may find applications in various industries beyond woodworking, such as metal fabrication, automotive manufacturing, aerospace, and other fields where precise temperature control during abrasive operations is critical.Advantages

[0087] The cooling unit for a cross-cut sander described in the present invention offers several significant technical advantages. First, the introduction of compressed air through appropriately positioned nozzles or an air knife allows for effective cooling of the abrasive belt during the sanding process. This allows for maintaining optimal operating temperatures even when processing large panels, significantly reducing the risk of thermal damage to heat-sensitive materials such as melamine or painted panels.

[0088] Another advantage of the present invention is the diagonal configuration of the slats of the support or slat belt, combined with the appropriately directed air flow, which creates a synergistic effect that improves cooling efficiency without compromising the quality of the sanding, maximizing heat extraction, reducing the turbulence of the cooling air flow.

[0089] Another advantage of the present invention is the integration of an air extraction hood on the opposite side of the nozzles, which ensures effective dust control, improving both the quality of the finish and the working environment. Overall, this technical solution offers a significant improvement in the efficiency and quality of the cross-sanding process, allowing for greater productivity and versatility in the processing of different types of panels.

[0090] The present invention has been described for illustrative but not limitative purposes, according to its preferred embodiments, but it is to be understood that modifications and / or changes can be introduced by those skilled in the art without departing from the relevant scope as defined in the enclosed claims.

Claims

1. Sander machine (1) for sanding a piece (P), such as panels made of wood, plastic, fiberglass, and the like, comprising: a frame (11) having an entrance (111) for the entry of a piece (P) to be sanded, and an exit (112) for the exit of the sanded piece (P), wherein the piece (P) is moved from said entrance (111) to said exit (112) along an advancement direction (A); a main sanding group (2) positioned between said entrance (111) and said exit (112) for sanding the piece (P); and a transverse sanding group (3) positioned between said entrance (111) and said exit (112), and comprising an abrasive belt (31), having a first abrasive face and a second face, opposite said first face, movement means (32) for said abrasive belt (31), capable of moving said abrasive belt (33) along a dragging direction (L) at a dragging speed to perform the sanding of said piece (P), wherein said dragging direction (L) is substantially perpendicular or oblique with respect to said advancement direction (A); and a lamellar belt (33) having a plurality of lamellae (34), arranged so that said lamellae (34) are in contact with said second face of said abrasive belt (31); wherein said sander machine (1) is characterized in that said transverse sanding group (3) comprises a cooling unit (4) having an air source (41) for supplying air of a cooling air flow (Fc), one or more openings or nozzles (43) to direct said cooling air flow (Fc) from said air source (41) onto said lamellar belt (33), wherein said cooling air flow (Fc) passes through the lamellae (34) of said lamellar belt (33), so as to pass between said abrasive belt (31) and said lamellar belt (33).

2. Sander machine (1) according to the preceding claim, characterized in that the dragging speed of said abrasive belt (31) and the air speed of the cooling air flow (Fc) are coordinated so that the relative direction of the cooling air flow (Fc) is substantially parallel to the inclination direction of the lamellae (34) of said lamellar belt (33).

3. Sander machine (1) according to any one of the preceding claims, characterized in that said cooling unit (4) comprises a plurality of said openings or nozzles (43) distributed transversely with respect to the advancement direction (A) of the piece (P).

4. Sander machine (1) according to the preceding claim, characterized in that it comprises a reading barrier (5), positioned at said entrance (111), comprising a plurality of flaps (51) arranged adjacent to each other, transversely with respect to said advancement direction (A) of the piece (P), wherein said reading barrier (5) is adapted to detect the length and / or width of the piece (P) to be sanded entering through said entrance (111); and in that the nozzles (53) corresponding to the flaps (51) lifted following the introduction of a piece (P) to be sanded are activated.

5. Sander machine (1) according to any one of the preceding claims, characterized in that said air source is an electric fan (41), and in that said cooling unit (4) comprises one or more ducts for the supply of cooling air (42), which fluid-dynamically connect said air source (41) to said openings or nozzles (43).

6. Sander machine (1) according to any one of the preceding claims, characterized in that said main sanding group (2) comprises an upper sanding roller (21) arranged transversely with respect to said advancement direction (A) of the piece (P), a return roller (22) positioned above said sanding roller (21), a longitudinal sanding belt, positioned between said upper sanding roller (21) and said return roller (22), and a lower roller (24) positioned below said upper sanding roller (21), facing said upper sanding roller (21); and in that said transverse sanding group (3) is positioned downstream of said main sanding group (2).

7. Sander machine (1) according to any one of the preceding claims, characterized in that said cooling unit (4) comprises collecting means (44) for the heated air flow (Fh) from said abrasive belt (31), positioned facing said openings or nozzles (43) on the opposite side of said openings or nozzles (43) with respect to said abrasive belt (31).

8. Sander machine (1) according to the preceding claim, characterized in that said collecting means (44) comprise a plurality of hoods (441), arranged adjacent to each other, and one or more ducts for the extraction of hot air (45) for the extraction of air.

9. Sander machine (1) according to any one of the preceding claims, characterized in that it comprises a buffer roller (6) to apply pressure on the panel (P) to hold it in place during the sanding stages.

10. Transverse sanding group (3) comprising: an abrasive belt (31) having a first abrasive face (311) and a second face, opposite said first face; movement means (32) for said abrasive belt (31), capable of moving said abrasive belt (33) along a dragging direction (L) at a dragging speed to perform the sanding of said piece (P), wherein said dragging direction (L) is substantially perpendicular or oblique to said advancement direction (A); and a lamellar belt (33) having a plurality of lamellae (34), arranged so that said lamellae (34) are coupled to said second face of said abrasive belt (31); characterized in that it comprises a cooling unit (4) having an air source (41) for supplying air of a cooling air flow (Fc), one or more openings or nozzles (43) to direct said cooling air flow (Fc) from said air source (41) onto said lamellar belt (33), wherein said cooling air flow (Fc) passes through the lamellae (34) of said lamellar belt (33), so as to pass between said abrasive belt (31) and said lamellar belt (33).

11. Transverse sanding group (3) according to claim 10, characterized in that the dragging speed of said abrasive belt (31), and the air speed of the cooling air flow (Fc) are coordinated so that the relative direction of the cooling air flow (Fc) is substantially parallel to the inclination direction of said lamellae (34).

12. Transverse sanding group (3) according to any one of claims 10 or 11, characterized in that said cooling unit (4) comprises a plurality of openings or nozzles (43) distributed transversely with respect to the advancement direction (A) of the piece (P).

13. Transverse sanding group (3) according to any one of claims 10-12, characterized in that said air source is an electric fan (41), and in that said cooling unit (4) comprises one or more ducts for the supply of cooling air (42), which fluid-dynamically connect said air source (41) to said openings or nozzles (43).

14. Transverse sanding group (3) according to any one of claims 10-13, characterized in that said cooling unit (4) comprises collecting means (44) for the heated air flow (Fh) from said abrasive belt (31), positioned facing said nozzles (43) on the opposite side of said nozzles (43) with respect to said abrasive belt (31), wherein said collecting means (44) comprise a plurality of hoods (441), arranged adjacent to each other.

15. Method (100) for cooling an abrasive belt (33) in a sander machine (1) for a piece (P), comprising: advancing (110) a piece (P) through a sanding group (3) of the sander machine (1); and moving (120) an abrasive belt (33) in a transverse direction (L) relative to the advancement of the piece (P); characterized in that it comprises the steps of: directing (130) a cooling air flow (Fc) through a plurality of openings or nozzles (43) onto a lamellar belt (33) supporting the abrasive belt (31), wherein the cooling air passes through the lamellae (331) of the lamellar belt (33) between the abrasive belt (31) and the lamellar belt (33).

16. Method (100) according to the preceding claim, wherein said lamellar belt (33) comprises a plurality of lamellae (331) arranged diagonally with respect to the advancement direction (A) of the piece (P).

17. Method (100) according to any one of claims 15 or 16, further comprising the step of coordinating (140) the dragging speed of said abrasive belt (31) and the speed of the cooling air flow (Fc), so that the relative direction of the cooling air is parallel to the inclination direction of said lamellae (34).

18. Method (100) according to any one of claims 15-17, further comprising the step of collecting (150) the cooling air through a collection hood (44) positioned on the opposite side of said openings or nozzles (43) with respect to the abrasive belt (31).

19. Method (100) according to any one of claims 15-18, further comprising the steps of: detecting (160) the length and / or width of the piece (P) by means of a reading barrier (5) comprising a plurality of flaps (51); and activating said openings or nozzles (43) corresponding to the flaps (51) lifted by said reading barrier (5).

Images