Belt grinder for creating surface structures

Abstract

A workpiece (10) passes through a belt grinder (100) for grinding and structuring a flat workpiece (10) in a predefined direction of passage (P1) past at least one machining region of a structuring device (200). The structuring device (200) comprises at least one endless grinding belt (210) which is guided via deflecting elements (212, 214, 216) in at least one direction of revolution (P3) and the width of which extends substantially across the working width of the belt grinder (100, 120), and is guided via deflecting elements (212, 214, 216), the longitudinal axes of which are oriented transversely to the direction of passage (P1) of the workpiece (10). Furthermore, the structuring device (200) comprises an endless pressing belt (220) which is configured and arranged such that it exerts a force from the inside on the grinding belt (210) in a pressing region (229), wherein the endless pressing belt (220) is able to be driven with the aid of a drive unit. The direction of revolution (P2) of the pressing belt (220) runs, at least in the pressing region (229), transversely to the direction of revolution (P3) of the grinding belt (210). The structuring device (200) and the transport unit (110) are configured and arranged such that the workpiece (10) guided past the structuring device (200) comes into contact with the machining region of the grinding belt (210). The structuring device (200) comprises a control unit (510) which controls the drive unit of the pressing belt (220) such that the drive unit selectively drives the endless pressing belt (220) in a first direction of revolution (P2) or in a second direction of revolution that is opposite to the first direction of revolution (P2).

Description

[0001] The invention relates to a belt sanding machine for sanding and texturing a flat workpiece, in which the workpiece passes through the belt sanding machine in a predetermined direction. The belt sanding machine comprises at least one texturing device for creating surface textures. The texturing device has at least one endless sanding belt guided by deflection elements in at least one direction of rotation and an endless pressure belt, which is designed and arranged such that it exerts an internal force on the sanding belt in a pressure area, wherein the pressure belt can be driven by means of a drive unit.

[0002] Document DE 10 2004 037 148 C5 discloses a belt sanding machine according to the preamble of claim 1, namely a sanding station for a belt sanding machine with at least one endless sanding belt guided over deflection rollers and a pressure flap belt circulating within it for pressing the sanding belt against a workpiece. The pressure flap belt causes an effective sanding process only in the areas where the pressure flaps exert a pressure force on the sanding belt in the direction of the workpiece to be machined. This creates short cuts in the surface of the workpiece along the pressure flaps of the pressure flap belt by the abrasive particles of the sanding belt.The close arrangement of the lamellae of the pressure lamella belt ensures a uniform force transmission from the pressure lamella belt to the grinding belt across the entire working width of the grinding station, resulting in a uniform grinding pattern without bumps or depressions.

[0003] Document EP 1 530 509 B1 discloses a grinding machine for grinding the surface of a workpiece, with vibratory drive means to set the abrasive in an oscillating grinding motion. The grinding machine further comprises an activation device with a plurality of controllable activation areas, so that different areas of the abrasive can be activated alternately, independently of the oscillating grinding motion. The provision and control of the activation areas is relatively complex. The aim is to obtain a surface without directional grinding marks. The oscillating grinding principle generates a circular motion; the alternating pressure areas are intended to irregularly interrupt this circular cutting motion. These grinding marks cannot be larger than the diameter of the circular motion.

[0004] Document DE 196 01 379 C2 discloses a device for pressing a circulating abrasive belt of a belt sander against the surface of a workpiece. The device has a pressure bar with a plurality of controllable actuators.

[0005] Document US 8,771,037 B2 discloses a grinding device for imprinting a specific pattern onto a workpiece. Pressure elements press against the inside of a pressure belt, whose pressure elements thereby press against the inside of the grinding belt.

[0006] Document EP 2 504 125 B1 discloses a device for machining a workpiece in which a carrier element with pressure means is provided, which can be driven independently of a circulating machining belt.

[0007] Document EP 3 326 750 A1 discloses a grinding machine for grinding the surface of a workpiece, wherein the grinding machine has at least one circulating grinding belt and at least one pressure bar for exerting pressure on the grinding belt. A plate is arranged between the grinding belt and the pressure bar, which is movably mounted in a plane perpendicular to the direction of the exerted pressure. The plate is provided with raised areas, the arrangement of which is freely variable. Due to this point arrangement, the grinding forces are also transmitted irregularly, producing an irregular depth structure. Lateral movement is also severely restricted by the described solution.

[0008] However, for some applications it is desirable to incorporate structures into the surface of a workpiece to be machined, in order to obtain a desired surface texture that deviates from a flat surface. This surface texture should be achievable across the entire working width of a belt sander with a simple machine design.

[0009] Based on this, the object of the invention is to create a belt sander that can also produce continuous surface structures across the entire working width. These surface structures can preferably be straight or wavy.

[0010] This problem is solved by a belt grinding machine according to the features of claim 1. Advantageous further developments are specified in the dependent claims.

[0011] In particular, because the pressure belt can be driven in a first direction of rotation and in a second direction of rotation opposite to the first, and because the direction of rotation of the pressure belt runs transversely to the direction of rotation of the abrasive belt, at least in the pressure area, different surface structures can be created when processing a workpiece using such a structuring device. In particular, this allows for the creation of an uneven and profiled surface on the workpiece. Preferably, tracks and the surface of the workpiece to be processed can be ground into the surface. For this purpose, the pressure elements can exert a point force on the abrasive belt. This allows a force to be exerted on the abrasive belt from the inside, enabling the creation of continuous surface structures across the entire working width of the workpiece.

[0012] At least in the pressure zone, the pressure belt comprises at least one pressure element, preferably at least one arrangement with several pressure elements, each of which exerts a pressure force on the inside of the abrasive belt in the direction of a workpiece to be processed. The pressure zone is generally the area of ​​the pressure belt in which the pressure elements of the pressure belt exert a force on the inside of the abrasive belt. Each of the pressure elements located in the pressure zone exerts a force from the inside onto the abrasive belt in the direction of a workpiece to be processed, either at a single point or over an area whose longest dimension is smaller than the width of the pressure belt, at least when a pressure element of a pressure bar is activated and the area of ​​the pressure belt containing the pressure element is located between the pressure element and the abrasive belt.The pressure bar comprises several individually controllable and activatable pressure elements arranged one behind the other in the direction of rotation of the pressure belt, so that the pressure area of ​​all pressure elements preferably extends over the entire working width of the structuring device. This makes it particularly easy to exert a force from the inside on the abrasive belt, enabling the creation of continuous surface structures across the entire working width of the workpiece.

[0013] The pressure elements preferably have a spherical shape. Alternatively or additionally, the pressure elements are arranged symmetrically about at least one axis of symmetry, wherein the axis of symmetry runs in the direction of rotation of the pressure belt and / or transversely to the direction of rotation of the pressure belt.

[0014] A control unit directs the drive unit either to move the pressure belt back and forth according to a first drive pattern or to move the pressure belt back and forth according to a second drive pattern. This allows for the easy creation of different surface textures.

[0015] The pressure belt has a first section with a first arrangement of pressure elements and a second section with a second arrangement of pressure elements. This allows different surface textures to be created easily.

[0016] By controlling the drive unit to move the pressure belt with different drive patterns using a control unit and by providing at least two sections with different arrangements of pressure elements, a variety of different surface structures can be created.

[0017] The pressure belt is designed and positioned such that it exerts a force on the inside of the abrasive belt within a pressure area. The inside of the endless abrasive belt is the side that contacts the deflection elements through which the belt is guided. Therefore, the inside of the endless abrasive belt is the side without abrasive material, i.e., the opposite or reverse side of the abrasive-coated side of the endless abrasive belt.

[0018] It is particularly advantageous if the first arrangement of pressure elements comprises a first set of pressure elements, and the second arrangement comprises a second set of pressure elements that differs from the first set. Alternatively or additionally, the first arrangement can comprise pressure elements in a first arrangement, and the second arrangement can comprise pressure elements in a second arrangement. The pressure elements can be fixed or detachably mounted on the pressure belt and, if necessary, can be elastically deformed under appropriate force. This allows for easy adjustment of the desired pressure effect. Furthermore, elastically deformable pressure elements are particularly robust and can easily adapt to the contours of the workpieces being machined, thus achieving the desired grinding results even in the area of ​​the workpiece's edges.

[0019] It is particularly advantageous if the first and second arrangements of pressure elements comprise the same pressure elements. The density of the pressure elements and / or the structure of their arrangement in the first and second sections then differ, resulting in different forces being exerted on the abrasive belt from the inside, depending on whether the pressure elements of the first section or those of the second section are exerting a force on the belt from the inside.

[0020] The pressure elements of the respective arrangement can include, in particular, circular, oval, and / or rectangular pressure pieces. Desired surface textures can be easily created using such pressure elements. Furthermore, these pressure elements can be designed to be very robust.

[0021] It is particularly advantageous if the first and second sections are arranged one behind the other in the direction of movement or longitudinal motion of the pressure belt. This allows for easy switching of the effective pressure areas. Continuous or discontinuous drive of the pressure belt is also possible, so that the first or second pressure area alternately exerts a force from within on the abrasive belt, thus enabling the creation of different surface textures.

[0022] Furthermore, it is advantageous if the pressure belt can be driven in a first direction of rotation and in an opposite second direction of rotation by means of the drive unit. According to the invention, the pressure belt is moved back and forth according to a drive pattern. The back-and-forth movement can be performed with a preset amplitude and / or predefinable frequency. This, in conjunction with the pressure elements of the first section and the second section, and in conjunction with the abrasive belt, allows a desired surface structure to be produced.

[0023] Furthermore, it is advantageous if the control unit can selectively control the drive unit in such a way that only the first section, only the second section, or alternately the first and second sections, or at least partially simultaneously the first and second sections, or parts of the first and parts of the second section, or several first and several second sections of the pressure belt press against the abrasive belt from the inside. This provides a simple way to selectively create a variety of different surface structures on the workpiece being processed.

[0024] Furthermore, additional sections besides the first and second sections can be provided, which also have different printing properties. In particular, a third and a fourth section can be provided.

[0025] Furthermore, it is advantageous if the shape, size, and / or spacing of the pressure elements change continuously along the circumference of the pressure belt. This results in at least two sections of the pressure belt having different arrangements of pressure elements. By continuously changing the shape, size, and / or spacing of the pressure elements along the circumference of the pressure belt, a continuous change in the surface structure that can be generated on a workpiece can be easily achieved.

[0026] Furthermore, it is advantageous if the pressure belt is guided over at least two deflection elements, preferably around at least two deflection rollers. This allows for simple and reliable guidance of the pressure belt. It is particularly advantageous if the drive unit drives at least one of the deflection rollers to drive the pressure belt. This enables a simple and space-saving design of the structuring device.

[0027] Furthermore, it is advantageous if the drive unit for the pressure belt is a first drive unit and if the structuring device has a second drive unit for the abrasive belt. This allows for independent control of the abrasive belt and the pressure belt.

[0028] Furthermore, it is advantageous if the deflection elements around which the endless abrasive belt is guided are deflection rollers, with the endless abrasive belt preferably guided over at least three deflection rollers. This allows for a simple and robust design of the structuring device.

[0029] Furthermore, it is advantageous if a sliding layer is arranged between the pressure belt and the endless grinding belt.

[0030] Furthermore, it is advantageous if the structuring device is designed as a belt sanding station with a wide sanding belt running parallel to the workpiece's direction of travel, the width of which extends essentially over the working width of the belt sander and is guided by deflection elements oriented transversely to the workpiece's direction of travel. This allows for a simple design of the entire belt sander.

[0031] Furthermore, it is advantageous if the structuring device comprises at least one pressure bar by which a force can be exerted from the inside onto the pressure belt in the direction of the abrasive belt. This allows a predetermined pressure force to be exerted on the pressure belt, so that the pressure belt exerts a predetermined pressure force on at least part of the pressure area on the inside of the abrasive belt.

[0032] It is particularly advantageous if the pressure belt exerts an internal force on the sanding belt, at least in part of the pressure area, when a pressure element of the pressure bar is activated. The pressure bar comprises several individually controllable pressure elements arranged one behind the other in the direction of rotation of the pressure belt, which can be activated to generate a pressure force in the pressure area when appropriately controlled. This allows parts of the pressure area to be selectively subjected to a pressure force.

[0033] Furthermore, it is particularly advantageous if the pressure elements can be controlled in such a way that the pressure elements of the pressure belt, arranged between a controlled pressure element and the abrasive belt, exert a pressure force on the inside of the abrasive belt. This allows desired patterns to be applied to specific areas of the surface of the workpiece being processed.

[0034] Furthermore, it is advantageous if the pressure belt includes pressure elements that are arranged side by side in several rows in the direction of rotation.

[0035] Preferably, the pressure elements generate a pressure force within a specific pressure area. The distance between two adjacent pressure elements is selected such that there is little or no force transmission from the pressure belt to the abrasive belt between these pressure element pressure areas. This allows for the creation of an uneven surface.

[0036] Furthermore, it is advantageous to arrange pressure elements on the pressure belt in a continuous pattern across the entire working width. This allows, for example, the creation of surface textures with diagonal lines.

[0037] The pressure elements can be arranged symmetrically to an axis in the direction of rotation of the pressure belt or to at least one axis transverse to the direction of rotation of the pressure belt.

[0038] Furthermore, the pressure elements can be designed and arranged in such a way that force is transmitted to the inside of the sanding belt in point pressure areas.

[0039] The effective pressure areas of the pressure elements are preferably as large as possible so that a visible grinding result is still produced, i.e., a defined pattern visible on the workpiece due to the pressure element in the grinding result, and thus no flat grinding result is produced.

[0040] Furthermore, the structuring device can generate oscillation marks as a surface structure on the workpiece surface to be processed, in particular by creating a visible, defined pattern using at least one pressure element on the workpiece surface and by moving the pressure belt back and forth with the aid of the drive unit to drive the pressure belt. In particular, a pattern symmetrical to the direction of rotation of the abrasive belt can be generated on the surface of the abrasive belt. A sensor unit for workpiece detection can also be provided, wherein a control unit then controls the pressure elements of the pressure bar depending on a signal from the sensor unit.

[0041] In general, the structuring device can be designed in such a way that the surface of the workpiece processed with the aid of the structuring device has a non-surface grinding result, which in particular comes close to a non-surface grinding.

[0042] Further features and advantages will become apparent from the following description, which, in conjunction with the attached figures, explains exemplary embodiments in more detail.

[0043] They show: Fig. 1 a perspective view of a belt sander with a structuring device designed as a sanding station according to an exemplary embodiment; Fig. 2 a schematic top view of an arrangement for processing flat workpieces with a belt sander according to Fig.1 ; Fig. 3 a simplified schematic representation of an arrangement for driving and guiding a pressure belt for use in the belt grinding machine according to Fig. 1 ; Fig. 4 a top view of a along the dividing line AA in Fig. 3 separated pressure belt according to a first embodiment; Fig. 5 a top view of a belt along the separation line AA in Fig. 3 separated pressure belt according to a second embodiment; Fig. 6 a top view of a belt along the separation line AA in Fig. 3 separated pressure belt according to a third embodiment; Fig. 7 a top view of a belt along the separation line AA in Fig. 3 separated pressure belt according to a fourth embodiment; Fig. 8 a top view of a belt along the separation line AA in Fig. 3 separated pressure belt according to a fifth embodiment; Fig. 9 a top view of a belt along the separation line AA in Fig. 3 separated pressure belt according to a sixth embodiment; Fig. 10 a top view of a belt along the separation line AA in Fig. 3 separated pressure belt according to a seventh embodiment; Fig. 11 a top view of a belt along the dividing line AA in Fig. 3 separated pressure belt according to an eighth embodiment; Fig. 12 a top view of a belt along the separation line AA in Fig. 3 separated pressure belt according to a ninth embodiment; Fig. 13 a top view of a belt along the dividing line AA in Fig. 3 separated pressure band according to a tenth embodiment; Fig. 14 a sectional view of a first variant of a single pressure element and a section of the pressure band according to the first embodiment according to Fig. 4 ; Fig. 15 a sectional view of a second variant of a single pressure element and a section of the pressure band according to the first embodiment according to Fig. 4 ; Fig. 16 a sectional view of a third variant of a single pressure element and a section of the pressure band according to the first embodiment according to Fig. 4 ; Fig. 17 a sectional view of a fourth variant of a single pressure element and a section of the pressure band according to the first embodiment according to Fig. 4 ; Fig. 18 a sectional view of a fifth variant of a single pressure element and a section of the pressure band according to the first embodiment according to Fig. 4 ; and Fig. 19 a sectional view of a sixth variant of a single pressure element and a section of the pressure band according to the first embodiment according to Fig. 4 .

[0044] Fig. 1 Figure 1 shows a perspective view of a belt grinding machine 100 with a structuring device 200 designed as a grinding station, according to one embodiment. In addition to the structuring device 200, the belt grinding machine 100 comprises a conveyor belt 110, which is guided around two deflection rollers 112, 114 and which carries workpieces 10 to be processed by the structuring device 200 past a processing area of ​​the structuring device 200 in the direction of arrow P1. The structuring device 200 comprises an endless grinding belt 210, which is guided around three deflection rollers 212, 214, 216. In other embodiments, only two deflection rollers or more than three deflection rollers may be provided. Alternatively, other deflection elements, such as deflection plates, may be provided instead of the deflection rollers 212, 214, 216.

[0045] Inside the endless grinding belt 210, a pressure belt 220 is arranged, guided over deflection rollers 222, 224. Pressure elements are formed on the circumferential surface of the pressure belt. The pressure elements in a first section 230 have a first size and are arranged in a first arrangement, and in a second section 240 have a second size and are arranged in a second arrangement. A pressure element of the first section 230 is designated by reference numeral 232, and a pressure element of the second section 240 is designated by reference numeral 242.

[0046] In the present embodiment, the deflection roller 224 can be driven by a first drive unit to drive the pressure belt 220. In other embodiments, the other deflection roller 222, a further deflection roller, or both deflection rollers 222 and 224 can also be driven. Depending on the control signal of the first drive unit, the pressure belt 220 can be driven either in the direction of rotation P2 or in the opposite direction to the direction of rotation P2. This also allows for a back-and-forth movement of the pressure belt 220 to create different surface textures. A sliding layer 250 is arranged between the pressure belt 220 and the inner surface 211 of the endless abrasive belt 210, reducing friction compared to direct contact between the pressure belt 220 and the inner surface 211 of the endless abrasive belt 210.This reduces, in particular, the abrasion on the inside of the abrasive belt 210 and the associated wear of the abrasive belt 210. The pressure elements 232, 242 of the pressure belt 220 press against the inside 211 of the abrasive belt 210 in a pressure area, whereby the sliding layer 250 can be arranged between the pressure elements 232, 242 and the inside 211 of the abrasive belt 210. In other embodiments, no sliding layer 250 is provided. The pressure area comprises the area of ​​the inside 211 of the abrasive belt 220 that is arranged opposite the pressure belt 220. Two corner points of the pressure area or surface are shown in . Fig. 1 Designated with reference numbers 226 and 227, and the imprint area with reference number 229.

[0047] Depending on the structure, shape and size of the pressure elements 232, 242 of the different sections 230, 240 and by a drive of the pressure belt 220, different surface structures can be produced when grinding the workpiece 10.

[0048] The structuring device 200 comprises a second drive unit for driving the endless grinding belt 210 in a direction of rotation P3 and / or opposite to the direction of rotation P3. Preferably, one of the deflection rollers 212, 214 and / or 216 is driven by means of this second drive unit.

[0049] The structuring device 200 according to the first embodiment is a longitudinal structuring device in which the direction of rotation P3 of the abrasive belt 210 in the pressure area 229 of the pressure belt 220 runs parallel to the transport direction P1 of the workpiece 10, i.e. the direction of rotation P3 of the abrasive belt 210 in the pressure area 229 of the pressure belt 220 is in or opposite to the transport direction P1 of the workpiece 10.

[0050] The structuring device 200 comprises at least one pressure bar 300, which is preferably connected to a frame of the structuring device 200 (not shown) and which includes several pressure elements 310, 312 arranged one behind the other in the direction of rotation P2 of the pressure belt 220. The pressure bar 300 is, in particular, arranged between the deflection rollers 222 and 224. The pressure bar 300 can exert a force from the inside onto the pressure belt 220 in the direction of the abrasive belt 210. In particular, the individual pressure elements 310, 312 of the pressure bar 300 can exert a predetermined pressure force on the pressure belt 220, such that the pressure belt 220 or the pressure elements 232, 242 exert a predetermined pressure force on at least a part of the pressure area 229 on the inside 211 of the abrasive belt 210.

[0051] When at least one pressure element 310, 312 of the pressure bar 300 is activated, it presses the pressure belt 220 against the inner surface 211 of the sanding belt 210 with a predetermined force, at least in a portion of the pressure area 229. The pressure elements 310, 312 can be individually controlled, so that, when activated accordingly, they exert a pressure force on the pressure belt 220 and the pressure elements 232, 242 located in the area of ​​the activated pressure element 310, 312 in the portion of the pressure area 229 opposite the pressure element. This allows a portion of the pressure elements 232, 242 to be individually and selectively subjected to a pressure force and exert corresponding pressure forces on the sanding belt 210 in the pressure area 229.

[0052] In particular, the pressure elements 310, 312 can be controlled by a control unit such that the pressure elements 232, 242 of the pressure belt 220, located between a controlled pressure element 310, 312 and the abrasive belt 210, exert a force on the inner surface 211 of the abrasive belt 210. This allows desired patterns to be applied to specific areas of the surface of the workpiece 10 to be processed. The pressure elements 310, 312 and the pressure bar 300 can be constructed and / or controlled in particular as disclosed in document DE 196 01 379 C2.

[0053] Fig. 2 Figure 1 shows a schematic top view of an arrangement 500 for processing flat workpieces 10. The arrangement 500 comprises the belt sander 100 with the conveyor unit, designed as a conveyor belt 110, for transporting the workpiece 10 in the direction of arrow P1 past the structuring device 200 for processing the workpiece 10. In the transport direction P1 upstream of the structuring device 200, i.e., upstream of the structuring device 200, a sensor unit 520 is arranged, which detects at least the arrival of the front edge of the workpiece 10 and generates at least one corresponding sensor signal. In other embodiments, the sensor unit 520 can additionally or alternatively also detect the side edges and the trailing edge of the workpiece 10.The generated sensor information is transmitted to the control unit 510, which then controls the drive units of the pressure elements 310, 320 of the pressure bar 300 depending on the signal from the sensor unit 520 and / or depending on the desired surface structure to be generated on the surface of the workpiece to be processed.

[0054] The sensor unit 520 can comprise light barriers, light sensors, laser distance measuring units, at least one camera, preferably a line scan camera, at least one inductive sensor and / or at least one reed contact, mechanical switches, in particular switching rollers, and ultrasonic sensors, in particular ultrasonic distance measuring sensors. The sensor unit 520 is preferably designed to detect any shape and / or position of the workpiece 10. Based on this, the control unit 510 can selectively choose areas and individually control the drive units of the pressure elements 310, 312.

[0055] In other embodiments, the sensor unit 520 can also be omitted if the geometry of the workpiece 10 is determined by inputting and / or transmitting corresponding data to the control unit 510. It is particularly advantageous if the sensor unit 520, for example, uses several laser distance measuring units to determine the surface profile of the workpiece 14 to be processed within the detection range of the sensor unit 520, wherein the respective detection range in the transport direction P1 subsequently corresponds to a processing area. This enables simple and precise control of the printing elements 310, 312 depending on the surface profile detected by the sensor unit 520 within the corresponding processing area.

[0056] Fig.3 shows a simplified schematic representation of an arrangement for driving and guiding the pressure belt 220 for use in a structuring device 200 according to Fig.1 The endless pressure belt 220, guided around the deflection rollers 222, 224, is described in the following Fig. 4 bis 13 separated along the dividing line AA, whereby the Fig.4 bis 13 Each figure shows a top view of the surface of the cut-open pressure band 220 according to twelve different embodiments.

[0057] Fig.4 shows a top view of a separated pressure band 220 according to a first embodiment, wherein the pressure band 220 according to the first embodiment is connected to the Fig.1 and 2The shown pressure band 220 corresponds to the first section 230. In the first section 230, the projecting circular pressure elements 232 have a first diameter and are arranged in three rows, with the columns being spaced the same distance apart as the rows. In the second section 240, the projecting circular pressure elements 242 have a smaller second diameter than the pressure elements 232 in the first section 230 and are arranged in four rows, with the columns being spaced the same distance apart as the rows.

[0058] Fig.5 Figure 1 shows a top view of a split pressure belt 220 according to a second embodiment, in which all pressure elements 232, 242 have the same diameter and are arranged in three rows with the same row spacing to each other, wherein the gap spacing decreases continuously from area 230 to area 240 or increases continuously from area 240 to area 230.

[0059] Fig.6 shows a top view of a split pressure belt 220 according to a third embodiment in which several first sections 230 and several second sections 240 are arranged one behind the other in the direction of rotation P2.

[0060] Fig.7 shows a top view of a separated pressure belt 220 according to a fourth embodiment, which is related to the first embodiment according to Fig.4 in the arrangement of the pressure elements 232, 242, wherein the pressure elements 232, 242, unlike in the first embodiment, have an oval head instead of a circular one.

[0061] Fig.8 shows a top view of a separated pressure belt 220 according to a fifth embodiment, which is related to the second embodiment according to Fig.5 the arrangement of the pressure elements 232, 242 is the same and differs in the shape of the pressure head of the pressure element 232, 242, wherein the pressure elements 232, 242 do not have a circular head but an oval head.

[0062] Fig.9 Figure 1 shows a top view of a separated pressure band 220 according to a sixth embodiment. The arrangement of the pressure elements 232, 242 according to the sixth embodiment is the same as that of the third embodiment. However, in the sixth embodiment, oval pressure elements 232, 242 are provided instead of circular ones.

[0063] Fig.10 Figure 1 shows a top view of a split pressure band 220 according to a seventh embodiment, wherein the arrangement of the pressure elements 232, 242 of the seventh embodiment is the same as that of the first embodiment, wherein square pressure elements 232, 242 are provided instead of circular pressure elements 232, 242.

[0064] Fig.11 Figure 1 shows a top view of a separated pressure belt 220 according to an eighth embodiment. The arrangement of the pressure elements 232, 242 corresponds to the arrangement of the pressure elements 232, 242 of the second embodiment. Fig.5 alike, whereby square pressure elements 232, 242 are used instead of the circular pressure elements 232, 242.

[0065] Fig.12 Figure 1 shows a top view of a separated pressure band 220 according to a ninth embodiment. The arrangement of the pressure elements 232, 242 corresponds to the arrangement of the pressure elements 232, 242 of the third embodiment. Fig.6 alike, except that square pressure elements are used instead of circular ones.

[0066] Fig.13 Figure 2 shows a top view of a separated pressure band 220 according to a tenth embodiment. In the first section 230, the pressure elements 232 are arranged in a first pattern and have a first size, and in the second section 240, the pressure elements 242 are arranged in a second pattern and have a second size.

[0067] Fig.14 shows a sectional view of a single pressure element 232, 242 and a section of the pressure band 220 according to the first embodiment according to Fig.4 , wherein the pressure elements 232, 234 are designed as cones.

[0068] Fig.15 shows a sectional view of a second variant of a pressure element 232, 244 and a section of the pressure band 220 according to the first embodiment according to Fig.4 , wherein the pressure element 232, 242 has a convex cross-section. In other embodiments, the pressure element 232, 242 can also be designed as a spherical segment.

[0069] Fig.16 shows a sectional view of a third variant of a single pressure element 232, 242 of the pressure band 220 according to the first embodiment according to Fig.4 . Unlike the first two variants, the pressure element 232, 242 is cylindrical.

[0070] Fig.17 shows a sectional view of a fourth variant of a single pressure element 232, 242 and a section of the pressure band 220 according to the first embodiment according to Fig.4 , wherein the pressure element 232, 242 according to the first variant after Fig.14 The pressure element 233, 243 is connected to the pressure band 220 via an additional rod-shaped element 233, 243. The head of the pressure element 232, 242 is located after Fig.17 corresponds to the pressure element 232, 242 according to the first variant. Fig.14 agree.

[0071] Fig.18 shows a sectional view of a fifth variant of a single pressure element 232, 242 and a section of the pressure band 220 according to the first embodiment according to Fig.4 , wherein the pressure element 232, 242 is connected to the pressure band 220 via a rod-shaped element 233, 243 and otherwise corresponds to the pressure element 232, 242 according to the second variant.

[0072] Fig.19 shows a sectional view of a sixth variant of a single pressure element 232, 242 and a section of the pressure band 220 according to the first embodiment according to Fig.4 The pressure element 232, 242 is connected to the pressure band 220 via a rod-shaped element 233, 243 and otherwise corresponds to the third variant. Fig.16 agree.

[0073] By connecting the pressure elements 232, 242 via a stem-shaped element 233, 243 to the pressure band 220, the respective pressure element 232, 242 can be pivoted under force by means of an elastic deformation of the stem-shaped element 233, 243 and adapt to the contours of the workpiece 10 to be machined.

[0074] In both the first section 230 and the second section 240 of the printing band 220, various printing elements 232, 242 can be combined, differing in both shape and size. A mixed arrangement of circular, square, or oval printing elements 232, 242 is also possible, with the individual printing elements 232, 242 differing in both shape and size. The [details of the information in the text are missing from the original text.] Fig.14 bis 19 The pressure elements shown relate to those in the Fig.4 , 5 , 6 , 13 circular pressure elements 232, 242 shown. The ones in the Fig.7, 8 und 9 The oval pressure elements 232, 242 shown can be used in the Fig.14 bis 19 The cross-sections shown are similar. Similarly, the cross-sections shown in the Fig.10 bis 12 shown square pressure elements 232, 242 which are in the Fig.14 bis 19 The cross-sections shown are shown. Reference symbol list

[0075] 10-surface workpiece 100Belt sander 110Conveyor belt 112, 114Drift roller 200Structuring device 210Sanding belt 211Inside of sanding belt 212, 214, 216, 222, 224Drift rollers 220Pressure belt 226, 227Corner point of pressure area 229Pressure area 230, 240Section 232, 242Pressure element 233, 243Round element 250Sliding layer 300Pressure bar 310, 312Pressure element 500Arrangement 510Control unit 520Sensor unit P1Transport direction P2, P3Direction of travel

Claims

1. Belt-grinding machine which is intended for grinding and structuring a flat workpiece (30) and in which the workpiece passes through the belt-grinding machine (10) in a predefined through-passage direction (P1), having at least one structuring device (200); and having at least one transporting unit (110) for transporting the workpiece (10) in the through-passage direction (P1) past a machining region of the structuring device (200), wherein the structuring device (200) comprises: - at least one continuous grinding belt (210), which is guided over deflecting elements (212, 214, 216) in at least one direction of circulation (P3) and of which the width extends essentially over the operating width of the belt-grinding machine (100, 120) and is guided over deflecting elements (212, 214, 216), of which the longitudinal axes are directed transversely in relation to the through-passage direction (P1) of the workpiece (10), - an endless pressure-exerting belt (220), which is designed and arranged such that it exerts a force on the grinding belt (210) from the inside in a pressure-exerting region (229), wherein the endless pressure-exerting belt (220) can be driven with the aid of a drive unit, - at least in the pressure-exerting region (229), the direction of circulation (P2) of the pressure-exerting belt (220) runs transversely in relation to the direction of circulation (P3) of the grinding belt (210), wherein the structuring device (200) and the transporting unit (110) are designed and arranged such that the machining region of the grinding belt (210) is in contact with the workpiece (10) guided past the structuring device (200), characterized in that the structuring device (200) comprises a control unit (510), which activates the drive unit of the pressure-exerting belt (220) in such a way that the drive unit drives the endless pressure-exerting belt (220) optionally in a first direction of circulation (P2) or in a second direction of circulation, which runs counter to the first direction of circulation (P2), in that the control unit (510) of the structuring device (200) optionally activates the drive unit in such a way that it moves the pressure-exerting belt (220) back and forth in accordance with a first drive pattern or it moves the pressure-exerting belt (220) back and forth in accordance with a second drive pattern, and in that the pressure-exerting belt (220) of the structuring device (200) has a first portion (230) with a first arrangement of pressure-exerting elements and at least one second portion (240) with a second arrangement of pressure-exerting elements.

2. Belt-grinding machine according to Claim 1, characterized in that the first arrangement of pressure-exerting elements comprises first pressure-exerting elements (232) and the second arrangement of pressure-exerting elements comprises second pressure-exerting elements (242), which differ from the first pressure-exerting elements (232), and / or in that the first arrangement of pressure-exerting elements comprises pressure-exerting elements (232, 242) in a first arrangement and the second arrangement of pressure-exerting elements comprises pressure-exerting elements (232, 242) in a second arrangement.

3. Belt-grinding machine according to either of preceding Claims 1 and 2, characterized in that the first arrangement of pressure-exerting elements and the second arrangement of pressure-exerting elements comprises the same pressure-exerting elements (232, 242), wherein there is a difference in the density of the pressure-exerting elements (232, 242) and / or the structure of the arrangement of the pressure-exerting elements (232, 242) in the first portion (230) and in the second portion (240).

4. Belt-grinding machine according to any one of the preceding claims, characterized in that the first portion and the second portion are arranged one behind the other in the direction of movement of the pressure-exerting belt (220).

5. Belt-grinding machine according to any one of the preceding claims, characterized in that the control unit (510) of the structuring device (200) optionally activates the drive unit in order to drive the pressure-exerting belt (220) in such a way that only the first portion (230) or only the second portion (240) or alternately the first and the second portions (230, 240) or at least partly simultaneously the first and the second portions (230, 240) or parts of the first and parts of the second portions (230, 240) or several first and several second portions of the pressure-exerting belt (220) push against the grinding belt (210) from the inside.

6. Belt-grinding machine according to any one of the preceding claims, characterized in that there is a continuous change in the shape of, the size of and / or the distance between the pressure-exerting elements (232, 242) along the circumference of the pressure-exerting belt (220).

7. Belt-grinding machine according to any one of the preceding claims, characterized in that the pressure-exerting belt (220) is guided over at least two deflecting elements (222, 224), preferably around at least two deflecting rollers (222, 224), and in that the drive unit drives at least one deflecting roller (222, 326) in order to drive the pressure-exerting belt (220).

8. Belt-grinding machine according to any one of the preceding claims, characterized in that the deflecting elements of the structuring device (200) are deflecting rollers (212, 214, 216), wherein the endless grinding belt (210) is preferably guided over at least three deflecting rollers (212, 214, 216).

9. Belt-grinding machine according to any one of the preceding claims, characterized in that a sliding layer (250) is arranged between the pressure-exerting belt (220) and the endless grinding belt (210).

10. Belt-grinding machine according to any one of the preceding claims, characterized in that the structuring device (200) comprises at least one pressure-exerting bar (300), by means of which a force can be exerted on the pressure-exerting belt (220), in the direction of the grinding belt (210), from the inside.

11. Belt-grinding machine according to Claim 10, characterized in that, at least upon activation of a pressure-exerting element (310, 312) of the pressure-exerting bar (300), the pressure-exerting belt (220) exerts a force on the grinding belt (210) from the inside at least in part of the pressure-exerting region (229), wherein the pressure-exerting bar (300) comprises several individually activatable pressure-exerting elements (310, 312), which are arranged one behind the other in the direction of circulation (P2) of the pressure-exerting belt (220) and, upon appropriate activation, can be activated in order to generate a pressure-exerting force in the pressure-exerting region (229).

12. Belt-grinding machine according to Claim 10 or 11, characterized in that the pressure-exerting elements (310, 312) can be activated in such a way that the pressure-exerting elements (232, 242) of the pressure-exerting belt (220) that are present between an activated pressure-exerting element (310, 312) and the grinding belt (210) exert a force on the inside of the grinding belt (210).

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