Abrasives

Abstract

The invention relates to an abrasive means, in particular a grinding wheel, for grinding a workpiece, comprising a carrier element (13), in particular a flexible one, comprising a plurality of grinding elements (15) for grinding a workpiece, and comprising a base binder element (17) for holding the grinding elements (15) on the carrier element (13). It is proposed that the abrasive means comprises a buffer element (71) formed from an elastomer for holding the base binder element (17) and / or the abrasive elements (15) on the carrier element (13).

Description

[0001] The invention relates to an abrasive according to the preamble of claim 1. State of the art

[0002] WO 2007 / 144915 A1 discloses a grinding wheel with a grinding element and with a plurality of holes that provide information. Disclosure of the invention

[0003] The invention is based on the object of improving an abrasive, in particular a grinding wheel, using simple constructive measures.

[0004] The object is achieved with an abrasive means, in particular a grinding wheel, for grinding a workpiece with a, in particular flexible, carrier element, with a plurality of grinding elements for grinding a workpiece and with a base binder element for holding or arranging the grinding elements on the carrier element, in particular on a grinding side of the carrier element.

[0005] It is proposed that the abrasive has a buffer element formed from an elastomer for holding the base binder element and / or the abrasive elements on the carrier element.

[0006] It may be expedient for the base binder element to be arranged on the buffer element. The base binder element can be arranged on a side of the buffer element facing away from the support element.

[0007] In particular, the carrier element can have a grinding region and a free region adjacent to the grinding region. Preferably, the free region is free of the base binder element, in particular each base binder element.

[0008] It may be expedient for the abrasive to have a size binder element for covering the grinding element, the base binder element and / or the buffer element, wherein the size binder element has a thickness that is smaller than the thickness of the buffer element. It is understood that these thicknesses should be measured in a free region, in particular a region between two adjacent groups of size binder elements. Adjacent to the base binder element(s), the thickness of the size binder element can increase. With increasing distance from the base binder element, the thickness of the size binder element can decrease. In the immediate vicinity of a plurality of base binder elements and the grinding elements connected to them, the size binder element applied to the grinding side can be drawn into the intermediate regions by means of a type of capillary action or surface tension distribution.In these areas, the top binder element can be thicker. This allows areas farther away from the top binder element to have a thinner base binder element. This can provide a particularly elastic abrasive.

[0009] The “abrasive” can be understood as a means which forms an accessory device of a grinding machine, in particular an eccentric grinding machine, and which, during operation, is in direct contact with the accessory device for removing material.

[0010] The abrasive can have a longitudinal extension or - in the case of a disc - a diameter of up to 500 mm, in particular up to 400 mm, preferably up to 300 mm, preferably up to 200 mm, particularly preferably up to 170 mm, such as 150 mm or even less. The abrasive can have a thickness of up to 5 mm, in particular up to 3 mm, preferably up to 2 mm, preferably up to 1 mm, particularly preferably up to 0.5 mm, such as 0.4 mm or even less.

[0011] To compensate for local unevenness during a grinding process and provide an optimal grinding pattern, the abrasive can be designed to be flexible. In particular, the abrasive is flexible if it is made of or contains a flexible material.

[0012] The abrasive can have a carrier element, in particular designed as a carrier layer, with a grinding side and a holding side facing away from the grinding side. The grinding side can have a plurality of grinding elements arranged directly or indirectly on the carrier element and / or held on the carrier element, in particular by means of a base binder element. The carrier element can be formed from paper, a film, a fabric, a fiber, etc., or from a combination thereof. However, other materials deemed appropriate by a person skilled in the art are also conceivable.

[0013] It may be expedient for the carrier element to be formed from a plastic, in particular a plastic layer. The carrier element may be formed from a plastic film. The carrier element may be formed from a thermoplastic. The carrier element may be deformable within a certain temperature range (thermoplastically), in particular reversibly. The carrier element may be deformable by heating and cooling below a decomposition temperature, in particular from a molten state. The carrier element may be weldable. The carrier element may be formed, for example, from a polyolefin such as polyethylene (PE), in particular high and / or low density, or polypropylene (PP). The carrier element may be formed, for example, from polyvinyl chloride (PVC), polystyrene (PS), polyester, polycarbonate (PC), or polyethylene terephthalate (PET).The carrier element can be made of bio-based plastics such as polylactide (PLA), cellulose acetate or starch blends.

[0014] The holding side can have a fastening means. The fastening means can be provided for arranging the abrasive on a machine tool, in particular a grinding disc of a machine tool. The fastening means can have a mechanical connecting element, such as a hook-and-loop fastener, a screw fastener, or a clamp fastener. The fastening means can have an adhesive connecting element, such as an adhesive fastener.

[0015] In this context, a “grinding element” is understood to mean an element that has a deforming and / or abrasive effect on the workpiece to be machined. A grinding element can be formed by a cutting grain, which in particular consists of a mineral and / or a ceramic material, such as diamond, corundum, silicon carbide, boron nitride, etc. The cutting grain can be made of a hard metal or another material that appears appropriate to a person skilled in the art. The cutting grain can have any geometric configuration that appears appropriate to a person skilled in the art, such as a 2-dimensional or 3-dimensional geometric configuration, for example in the form of a triangle, rectangle or trapezoid or as a cube, pyramid or cone.Likewise, a grinding element can be formed at least partially as an edge, a corner or a tapered portion of a surface structure which causes increased friction and temperature development on the workpiece to be machined, which has a deforming and / or abrasive effect on or in the workpiece to be machined.

[0016] The grinding element or the cutting grain can be designed as a broken or as a shaped cutting grain.

[0017] The base binder element can be arranged directly or indirectly on the carrier element. In an indirect arrangement, the carrier element can be arranged on an intermediate element, which in turn is arranged on the carrier element. The base binder element can extend over the carrier element in sections, in particular point-by-point or essentially over its entire surface. The base binder element can comprise or consist of polyurethane, epoxy, latices, acrylate, vinyl acetate, etc. The base binder element, in particular each base binder element, can be formed as a discrete point.

[0018] The base binder element can surround or envelop the grinding element in order to hold the grinding element to the carrier element in a material, force and / or form-fitting manner.

[0019] The base binder elements can be arranged on the carrier element and coated with abrasive elements using a spreading device, such as a conventional electrostatic spreading system. The abrasive elements can adhere to the areas coated with the base binder element. The abrasive elements, particularly excess ones, that do not adhere to the base binder element can be removed from the carrier element using a conveying device, such as a blow-out device or vibration of the abrasive.

[0020] It may be expedient for the abrasive to have a grinding region formed by means of base binder elements and / or grinding elements. It may be expedient for the grinding region to be formed from a plurality of base binder elements, in particular arranged at a distance from one another. The base binder element may be arranged partially on the carrier element. The base binder element may be arranged pointwise on the carrier element. The base binder element may cover the carrier element in sections, in particular discretely. The base binder element may not cover the carrier element over its entire surface.

[0021] A plurality of, in particular discrete, base binder elements can form a group of base binder elements. The group can form the grinding area. The group of base binder elements can be substantially circular. The group of base binder elements can be substantially triangular.

[0022] The group of basic binder elements can take on another geometric shape that appears appropriate to a person skilled in the art. The group can essentially be formed by an envelope that delimits the basic binder elements. The envelope can be arranged essentially along the basic binder elements and in particular tangentially to the basic binder elements. The group can form a type of island of basic binder elements. The basic binder elements of a group can be spaced apart from one another. The group can be formed from at least five, in particular at least six, preferably at least nine, basic binder elements.

[0023] A plurality of base binder elements can form a further group of base binder elements. The further group can form a further grinding area. The further group of base binder elements can be designed essentially analogously to the group of base binder elements. The groups can be spaced apart from one another. The groups can be spaced apart from one another by a greater distance than the distance between two adjacent base binder elements of a group. The groups of base binder elements can be spaced apart from adjacent base binder elements of a group by a greater distance, in particular by at least a factor of 2, in particular by at least a factor of 4, preferably by at least a factor of 6, preferably by at least a factor of 10, more preferably by at least a factor of 20.

[0024] The grinding area can be formed from a plurality of base binder elements, in particular arranged at a distance from one another. The base binder elements can be designed as points. The base binder elements can be designed in the form of islands, in particular base binder islands. The base binder elements can have an extension or a diameter of less than 3 mm, in particular less than 2 mm, preferably less than 1 mm, such as 0.7 mm. The base binder element can be formed from or consist of a phenolic resin, urea resin, polyurethane resin, polyester resin, optionally also UV-curing, etc. The base binder element can be cured material-specifically or depending on the base binder element used. The grinding area can be formed from one base binder element and / or from a plurality of base binder elements.The grinding area can be formed from a plurality of spaced-apart base binder elements. The base binder elements in the grinding area can be arranged in close proximity to one another. The base binder elements can accommodate a plurality of grinding elements and hold them, in particular in a bundle, directly or indirectly to the carrier element. As a result, areas or channels can be provided in the grinding area between the base binder elements that are free of a base binder element or grinding elements. These areas or channels can be provided for optimal dust transport.

[0025] The cover binder element can have a hardness that is greater than the hardness of the buffer element. The cover binder element can be designed to be less flexible than the buffer element. The Shore hardness of both elements can be determined as a hardness measurement method. This measurement method can be found in DIN EN ISO 868. This can prevent the grinding element from cracking because the buffer element reduces or prevents crack growth in the cover binder element in the direction of the crack.

[0026] It is proposed that the abrasive comprise a size binder element covering the base binder element and the grinding elements. The size binder element may have a watery consistency. The size binder element may be received between a plurality or a bundle of grinding elements by means of the capillary effect. Several grinding elements lying on a substantially point-shaped base binder element may form cavities into which the size binder element is received, in particular by means of the capillary effect. The cavities between the grinding elements may receive the size binder element. The cavities may draw the size binder element between the grinding elements.

[0027] It is further proposed that the abrasive have a further size binder element which covers the size binder element. The size binder element can be provided depending on the size, in particular the diameter, of the grinding element. For example, with a fine grinding element size, a size binder element can be dispensed with. A fine, in particular medium, size of the grinding elements can be achieved with less than 400, in particular less than 300. It is understood that a further size binder element can be provided. The size binder element or the further size binder element can be cured in a material-specific manner or depending on the size binder element or further size binder element used. The further size binder element can be formed from or consist of stearate, in particular a fatty acid. The further size binder element can be provided to absorb and / or bond grinding dust.The additional top binder element can form a kind of grease layer on the top binder element. The grease layer can be provided as a separating layer, which is intended to prevent or at least reduce clogging or clogging of the grinding side of the abrasive. This can optimize the grinding result.

[0028] It is further proposed that the cover binder element be formed from a non-transparent material. The cover binder element can be formed from a non-transparent material which is formed so thinly on the carrier element that the cover binder is transparent. The term “transparent” is to be understood as meaning an element if something arranged behind the element or lying behind it is recognizable, in particular in a visible spectrum. A transparent material can, for example, be transparent to radiation in the visible spectrum. It is understood that a transparent material can be determined by the fact that it is transparent to an operator or a human eye (without the use of technical devices). A visible spectrum is to be understood as meaning, in particular, electromagnetic radiation with wavelengths between approximately 380 nm and 750 nm. The cover binder element can be uncolored.The cover binder element can be at least 30%, in particular at least 50%, preferably at least 60%, more preferably at least 70%, more preferably at least 80%, particularly preferably at least 90%, transparent.

[0029] It is proposed that the size binder element have a layer thickness of less than 100 µm, in particular less than 50 µm, preferably less than 20 µm, preferably less than 10 µm, more preferably less than 5 µm, particularly preferably less than 2 µm. The thinner the layer thickness of the size binder element, the more flexible the abrasive. In particular, the size binder element can be transparent, depending on the layer thickness of the size binder element.

[0030] It may be expedient for the buffer element to be made of a plastic, in particular a plastic layer. The buffer element can be designed as a plastic film. The buffer element can be made of an elastomer. The buffer element can be dimensionally stable but elastically deformable. The buffer element can deform elastically when a force is applied, for example by means of a tensile or compressive force. The buffer element can return to its original or undeformed shape after a force has been applied, for example by means of a tensile or compressive force. The buffer element can be made of natural rubber or silicone rubber. The buffer element can be produced by vulcanization. This can improve the fracture toughness of the abrasive.

[0031] The buffer element can extend over the entire surface of the carrier element. The buffer element can cover one side, in particular a grinding side, of the carrier element, in particular completely. The buffer element can be formed, for example, from styrene-butadiene rubber (SBR), polyurethane (PU / PUR), polynitrile rubber (NBR), chloroprene rubber (CR), butadiene rubber (BR), ethylene-propylene-diene rubber (EPDM), ethylene-acrylate rubber (AEM), or acrylate rubber (ACM). The buffer element can be formed from a dispersion, in particular an aqueous one. The buffer element can be formed from a 100% system. The buffer element can be formed from a 2-component system. The buffer element can be solvent-free. The buffer element can be UV-curing.

[0032] It may be expedient for the buffer element to be arranged between the binder element and the carrier element. The buffer element can be softer, such as a binder element and / or a carrier element. The buffer element can be arranged, in particular directly, on the carrier element. Methods such as polymer dispersion, lamination, flame lamination, or application of a hotmelt element, in particular a hotmelt layer, can be considered for arranging or applying the buffer element to the carrier element.

[0033] It may be expedient for the grinding area to be formed by a base binder element delimiting the grinding area. This, in particular each, base binder element can delimit the grinding area. Furthermore, it may be expedient for the grinding area to be formed from a plurality of base binder elements, in particular arranged at a distance from one another. The base binder elements can be designed as a plurality of points. The base binder elements can be designed in the form of islands, in particular base binder islands. It is further proposed that the base binder element has an extent, in particular a diameter, preferably a maximum diameter, of less than 10 mm, in particular less than 8 mm, preferably less than 5 mm, preferably less than 3 mm, more preferably less than 1 mm, particularly preferably less than 0.5 mm.The base binder element can be made of or consist of a phenolic resin, urea resin, polyurethane resin, polyester resin, optionally also UV-curing, etc. The base binder element can be cured in a material-specific manner or depending on the base binder element used. The grinding area can be made of one base binder element and / or a plurality of base binder elements. The grinding area can be made of several spaced-apart base binder elements. The base binder elements in the grinding area can be arranged in a short-range order. The base binder elements can accommodate a plurality of grinding elements and hold them, in particular in a bundle, on the carrier element. As a result, areas or channels can be provided in the grinding area between the base binder elements which are free of a base binder element or grinding elements. These areas or channelsChannels can be provided for optimal dust transport.

[0034] Furthermore, it may be expedient for the grinding area to be surrounded by the free area. It may also be expedient for the grinding area to surround the free area. It may also be expedient for the free area to be substantially delimited by a plurality of base binder elements, in particular of the grinding area. The grinding area and the free area may have different visual properties. The grinding area and the free area, in particular their mutual boundaries, may form a contrast. The contrast may form an information pattern. This allows information to be provided to the user in a particularly simple manner.

[0035] Furthermore, it may be expedient for the abrasive to have an opening, in particular a suction opening, in particular for suctioning away grinding dust. The opening can be arranged in the free area. The opening can be spaced from the grinding area. The opening can extend through the carrier element, in particular through the entire abrasive. The opening can be designed as an opening. In this context, an “opening” should be understood to mean, in particular, a continuous hole, in particular through the entire material thickness of the abrasive. The opening can be designed as a round hole. However, other hole shapes that appear appropriate to a person skilled in the art, such as triangles, rectangles, squares, polygons, stars or combinations of these hole shapes, are also conceivable.The opening can have a diameter of up to 10 mm, in particular up to 7 mm, preferably up to 5 mm, more preferably up to 4 mm, particularly preferably up to 3 mm, such as 2.4 mm or even less. It can be expedient for the opening and the grinding region to delimit the free region. The opening can be surrounded by the free region, in particular completely, preferably in a plane by 360°. The opening can be delimited by the free region. This can prevent a grinding element from being hit, punched out, or lasered out when an opening is produced, for example by a punching process or a laser cutting process, whereby wear during production can be minimized.It may also be expedient for the opening to have an extension and for the free area to have an extension, wherein the extension of the opening, in particular each extension, is smaller than the extension of the free area. This allows an opening to be punched into the free area in a particularly advantageous manner, provided the extension of the free area is larger than the opening to be provided. Furthermore, it may be expedient for the free area to have at least two openings.

[0036] It may be expedient for the abrasive to have an edge region which delimits a, in particular maximum, extent of the abrasive and is free of a base binder element. The edge region can extend circumferentially around the abrasive. On the grinding side, the edge region can run along the entire extent of the abrasive. The edge region of the abrasive can be designed to be free-standing. This makes it possible to provide robust abrasives. This prevents or at least reduces tearing of the abrasive. In addition, tearing at an edge of the abrasive is prevented or at least reduced by a lever effect.

[0037] It may be advantageous for the abrasive to have a cover binder element covering the grinding area and the free area. The edge area may be formed free of the cover binder element.

[0038] It may also be expedient for the edge region to be delimited by the grinding region. It may furthermore be expedient for the edge region to be delimited by the free region. The edge region can be delimited, starting from a center point of the abrasive along a longitudinal extent and / or transversely, in particular perpendicular to a / the longitudinal extent, by the grinding region on the one hand and by the free region on the other hand. It may furthermore be expedient for the edge region to be delimited by a maximum extent of the abrasive on the one hand and by a distance of less than 5 mm, in particular less than 4 mm, preferably less than 3 mm, more preferably less than 2 mm, more preferably less than 1 mm, from the maximum extent of the abrasive on the other hand.In particular, the edge region can be delimited by a maximum extension of the abrasive on the one hand and by a distance of more than 0.1 mm, in particular more than 0.2 mm, preferably less than 0.4 mm, preferably more than 0.5 mm, more preferably more than 0.8 mm, from the maximum extension of the abrasive on the other hand. The edge region can be formed by an edge surface, in particular a diameter difference, preferably a maximum diameter difference, of less than 10 mm, in particular less than 8 mm, preferably less than 5 mm, preferably less than 3 mm, more preferably less than 1 mm. The edge region can be delimited by a first extension, in particular a first longitudinal extension, preferably a first diameter. The edge region can be delimited by a second extension, in particular a second longitudinal extension, preferably a second diameter.The first extension may be less than 3%, in particular less than 2%, preferably less than 1%, different from the second extension. The edge region may have a distance from the edge of the abrasive that is essentially independent of the abrasive or grinding wheel used. The distance may be essentially equidistant for wheels with a diameter of 80 mm, but also 170 mm.

[0039] The invention further relates to a hand-held power tool for receiving and operating an abrasive holding device and / or an abrasive.

[0040] The invention further relates to a grinding system comprising a hand-held power tool and an abrasive means intended for driving with the hand-held power tool. Short description of the drawings

[0041] Further advantages will become apparent from the following description of the drawings. The drawings illustrate exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also conveniently consider the features individually and combine them into useful further combinations. Herein: Fig. 1 a view and two exemplary sections of a grinding wheel according to the invention, Fig. 2 a view of another embodiment of the grinding wheel, Fig. 3 an enlarged view of the grinding wheel Fig. 2 and Fig. 4 an enlarged view of a grinding wheel without a cover binder element.

[0042] In the following figures, identical components are provided with the same reference numerals.

[0043] The figures each refer to an abrasive 11 designed as a grinding wheel 11 for grinding workpieces. The grinding wheel 11 according to the invention is universally applicable and is particularly suitable for machining workpieces made of metal, stone, wood, plastic, or a composite.

[0044] The grinding wheel 11 is intended for detachable mounting on commercially available, rotary-driven machine tools. The grinding wheel 11 can be mounted in a mounting device of a machine tool, preferably a hand-held power tool, which is already known to a person skilled in the art and is designed to accommodate the grinding wheel 11, with a rotational and / or translational movement on a workpiece to be machined. In particular, a translational feed is introduced into the tool by the machine tool operator applying a force to the machine tool, in particular to a machine tool housing.

[0045] The grinding wheel 11 is intended for detachable mounting on commercially available, rotary-driven machine tools. The grinding wheel 11 can be mounted in a mounting device of a machine tool that is already known to a person skilled in the art and designed to accommodate the grinding wheel 11. Typically, however, the grinding wheel 11 is detachably connected to the machine tool, in particular to a grinding disc or a support disc of the machine tool, by means of a material bond, such as an adhesive material bond, and / or by means of a hook-and-loop connection, such as a hook-and-loop connection.

[0046] Fig. 1 shows an abrasive means 11 designed as a grinding wheel 11 for grinding a workpiece with a flexible carrier element 13, with a plurality of grinding elements 15 for grinding a workpiece and with a base binder element 17 for holding or arranging the grinding elements 15 on a grinding side 31 of the carrier element 13.

[0047] The carrier element 13 has a grinding area 21 and a free area 23 adjacent to the grinding area 21. The free area 23 is free of one or the, in particular each, base binder element 17. The grinding area 21 forms an information pattern 27.

[0048] The grinding wheel 11 is disk-shaped and extends circumferentially around a rotational axis. It has a diameter of up to 150 mm. The grinding wheel 11 has a thickness of up to 5 mm or even less.

[0049] In order to be flexible, the grinding wheel 11 is made of a flexible material.

[0050] The grinding wheel 11 has a buffer element 71 formed from an elastomer for holding the base binder element 17 and / or the grinding elements 15 on the carrier element 13. The base binder element 17 is arranged on a side of the buffer element 71 facing away from the carrier element 13. The carrier element 13 has a grinding region 21 and a free region 23 adjacent to the grinding region 21. Preferably, the free region 23 is free of the, in particular each, base binder element 17 and in particular the grinding elements 15 held on the carrier element 13 by means of the base binder element 17.

[0051] The carrier element 13 is made of a plastic and forms a carrier layer in the form of a plastic layer. The carrier element 13 is made of a plastic film and a thermoplastic. The carrier element 13 is reversibly deformable within a certain temperature range (thermoplastic) and can be deformed from a molten state by heating and cooling below a decomposition temperature.

[0052] The carrier element 13 has a grinding side 31 and a holding side 33 facing away from the grinding side 31. The grinding side 31 has a plurality of grinding elements 15, which are arranged indirectly on the carrier element 13 and connected to the carrier element 13 by means of a base binder element 17. The grinding elements 15 form an abrasive layer with a predetermined grain size.

[0053] The holding side 33 has a fastening means (not shown in detail) which is provided for arranging the abrasive 11 on a grinding disc of a machine tool. The fastening means can comprise a mechanical connecting element, such as a hook-and-loop fastener, a screw fastener, or a clamp fastener. The fastening means can comprise an adhesive connecting element, such as an adhesive fastener.

[0054] The grinding element 15 or the cutting grain can be designed as a broken or as a shaped cutting grain.

[0055] The base binder element 17 is arranged indirectly on the carrier element and directly on the buffer element 71. The base binder elements 17 extend in sections pointwise over the carrier element 13 and are designed as discrete points. The base binder elements 17 surround the grinding elements 15 in order to hold them firmly, non-positively, and / or positively to the carrier element 13.

[0056] The base binder elements 17 are arranged on the carrier element 13 and are sprinkled with abrasive elements 15 using a conventional electrostatic scattering system. The abrasive elements 15 adhere to the areas coated with the base binder element 17. The excess abrasive elements 15 that do not adhere to the base binder element 17 are removed from the carrier element 13 using a conveying device, such as a blow-out device or vibration of the abrasive 11.

[0057] The grinding wheel has a grinding area 21 formed by base binder elements 17 and grinding elements 15. The grinding area 21 is formed from a plurality of spaced-apart base binder elements 15 and is partially arranged on the carrier element 13. The base binder element 15 is arranged at specific points on the carrier element 13. The base binder element 15 does not cover the carrier element or the buffer element 71 over its entire surface, but rather discretely in sections.

[0058] A plurality of discretely arranged base binder elements 15 forms a group 81 of base binder elements 15, which in turn forms the grinding area 21. The group 81 of base binder elements 15 can take on any shape. In the present case, the groups form a zigzag-shaped line ( Fig. 2), an information element, for example, in the form of the number eight ( Fig. 5 top left) or a trademark ( Fig. 5 below). The group is essentially formed by an envelope that delimits the basic truss elements, which is essentially bounded along the basic truss elements and in particular tangentially to the basic truss elements. The group forms a kind of island or island group of basic truss elements. The basic truss elements of a group are spaced apart from one another.

[0059] A plurality of base binder elements forms a further group of base binder elements. The further group is designed analogously to the group. The groups are spaced apart from one another. The groups are spaced further apart from one another, such as a, in particular minimal, distance between two adjacent base binder elements of a, in particular closed, group. The groups of base binder elements are spaced further apart from adjacent base binder elements of a group, in particular by a factor of at least 2, in particular by a factor of at least 4, preferably by a factor of at least 6, preferably by a factor of at least 10, preferably by a factor of at least 20.

[0060] The grinding area is formed from a plurality of spaced-apart base binder elements. The base binder elements are configured as points. The base binder elements have an extension or a diameter of less than 3 mm, in particular less than 2 mm, preferably less than 1 mm, such as 0.7 mm. The base binder elements accommodate a single or a plurality of grinding elements and hold them, in particular in a bundle, on the buffer element 71.

[0061] The size binder element has a hardness that is greater than the hardness of the buffer element 71. The size binder element is less flexible than the buffer element 71. The grinding wheel has a size binder element that covers the base binder element and the grinding elements. In an uncured state, the size binder element has a watery consistency. The size binder element can be received and held between a plurality of grinding elements by means of the capillary effect. Several grinding elements can lie on a substantially point-shaped base binder element to form free spaces for receiving the size binder element, into which the size binder element is received, in particular by means of the capillary effect.

[0062] The size binder element has a layer thickness of less than 100 µm in the free area or adjacent to the grinding area, in particular less than 50 µm, preferably less than 20 µm, preferably less than 10 µm, more preferably less than 5 µm, particularly preferably less than 2 µm. The thinner the layer thickness of the size binder element, the more flexible the abrasive is.

[0063] The size binder element has a layer thickness of more than 100 µm, in particular more than 150 µm, preferably more than 200 µm, and more preferably more than 300 µm, in the grinding zone. Accordingly, the size binder element has an inhomogeneous layer thickness across the entire extent of the grinding wheel. In the grinding zone, the layer thickness is at least 2 times greater than in the free zone.

[0064] The buffer element 71 is formed from a plastic layer. The buffer element 71 is designed as a plastic film. The buffer element 71 is formed from an elastomer. The buffer element 71 is dimensionally stable but elastically deformable. The buffer element 71 deforms elastically when a force is applied, for example by means of a tensile or compressive force. The buffer element 71 can return to its original or undeformed shape after a force is applied, for example by means of a tensile or compressive force. The buffer element 71 extends over its entire surface along the carrier element and completely covers the grinding side of the carrier element. It may be expedient for the buffer element 71 to be arranged between the binder element and the carrier element. The buffer element 71 can be softer, such as a binder element and / or a carrier element. The buffer element 71 can be arranged, in particular directly, on the carrier element.For arranging or applying the buffer element 71 to the carrier element, methods such as polymer dispersion, lamination, flame lamination or application of a hotmelt element, in particular a hotmelt layer, can be considered.

[0065] The grinding area 21 is formed by a plurality of base binder elements 17 delimiting the grinding area 21. The base binder elements 17 delimit the grinding area 21. The grinding area 21 is formed from a plurality of base binder elements 17 arranged at a distance from one another. The base binder elements 17 are designed as points and in the form of base binder islands. The base binder elements 17 have an extension or a diameter of less than 1 mm, such as 0.7 mm. The base binder elements 17 can be formed from a phenolic resin, urea resin, polyurethane resin, polyester resin, optionally also UV-curing, etc. The base binder elements 17 can be cured depending on the material or depending on the base binder element 17 used. The base binder elements 17 in the grinding area 21 are arranged in a short-range order relative to one another.The base binder elements 17 accommodate a plurality of grinding elements 15 and hold them bundled on the carrier element 13.

[0066] The grinding area 21 is surrounded by the free area 23, and the grinding area 21 surrounds the free area 23. The free area 23 is essentially delimited by a plurality of basic binder elements 17 of the grinding area 21. The grinding area 21 and the free area 23 have different visual properties and form a contrast that delimits the areas. The contrast, in turn, forms the information pattern 27.

[0067] In Fig. 2 and Fig. 3 the grinding areas and the free areas are zigzag-shaped and z-shaped respectively.

[0068] The grinding wheel 11 has an opening 37 designed as an extraction opening 37 for extracting grinding dust. The opening 37 is arranged in the free area 23 and spaced from the grinding area 21. The opening 37 extends through the carrier element 13 or through the entire grinding wheel 11 and is designed as an opening extending through the entire material thickness of the grinding wheel 11. The opening 37 has a circular hole shape and a diameter of up to 3 mm.

[0069] The opening 37 and the grinding area 21 delimit the free area 23. The opening 37 is completely surrounded by the free area 23 in a plane by 360°. The opening 37 is delimited by the free area 23.

[0070] The opening 37 has an extension and the free area 23 has an extension, wherein each extension of the opening 37 is smaller than each extension of the free area 23.

[0071] The free area 23 has at least two openings 37.

[0072] The abrasive 11 has a size binder element 39, which covers the base binder element 17 and the grinding elements 15. The size binder element 39 has a watery consistency and is received between a plurality or bundle of grinding elements 15 by means of the capillary effect. Several grinding elements 15, lying on a substantially point-shaped base binder element 17, form cavities into which the size binder element 39 is received by means of the capillary effect. The cavities between the grinding elements 15 receive the size binder element 39. The cavities draw the size binder element 39 between the grinding elements 15.

[0073] The grinding wheel 11 has a size binder element 39 for covering the grinding element, the base binder element 17 and / or the buffer element 71, wherein the size binder element 39 has a thickness S39 which is smaller than a thickness S71 of the buffer element 71. It is understood that these thicknesses should be measured in a free region, in particular a region between two adjacent groups of size binder elements 39. Adjacent to the base binder element(s) 17, the thickness of the size binder element 39 can increase. With increasing distance from the base binder element 17, the thickness of the size binder element 39 can decrease. In the immediate vicinity of a plurality of base binder elements 17 and the grinding elements 15 connected thereto, the size binder element 39 applied to the grinding side can be drawn into the intermediate regions by means of a type of capillary action or surface tension distribution.In these areas, the deck binder element 39 can be made stronger.

[0074] The abrasive 11 can have a further cover binder element 39 that covers the cover binder element 39. The cover binder element 39 can be provided depending on the diameter of the grinding element 15. For example, if the grinding elements 15 are finely sized, a cover binder element 39 can be dispensed with. A fine or medium size of the grinding elements 15 can be achieved with less than 400, in particular less than 300. It is understood that a further cover binder element 39 can be provided. The cover binder element 39 or the further cover binder element 39 can be cured depending on the material or depending on the cover binder element 39 or further cover binder element 39 used. The further cover binder element 39 can be formed from or consist of stearate, in particular a fatty acid. The further cover binder element 39 can be provided to absorb and / or bond grinding dust.The further cover binder element 39 can form a type of grease layer on the cover binder element 39. The grease layer can be provided as a separating layer, which is intended to prevent or at least reduce clogging or blockage of the grinding side 31 of the abrasive 11.

[0075] The size binder element 39 is formed from a non-transparent material. The size binder element 39 is formed from a non-transparent material that is formed on the abrasive 11 so thinly that the size binder element 39 is transparent. The size binder element 39 is uncolored. The size binder element 39 is at least 60% transparent.

[0076] The size binder element 39 has a maximum layer thickness D at the free region 23 of less than 10 µm. Preferably, the size binder element 39 has this maximum layer thickness D between two adjacent base binder elements 17. The thinner the layer thickness of the size binder element 39, the more flexible the abrasive 11 is. The size binder element 39 is transparent depending on the layer thickness of the size binder element 39.

[0077] The, in particular each, base binder element 17 has a maximum diameter of less than 1 mm. The base binder elements 17 are arranged at a distance from one another and formed on the information coating 28. The base binder elements 17 are applied to the information coating 28.

[0078] The information coating 28 can be applied to the carrier element 13, in particular to the grinding side 31 of the carrier element 13, using a conventional printing process, in particular an inkjet printing or a laser printing process. Accordingly, the information coating 28 can be colored.

[0079] The grinding wheel 11 has an edge region 41 which limits the maximum diameter of the grinding wheel 11 and is free of base binder elements 17 ( Fig. 1, top). The edge region 41 extends in the circumferential direction around a center point or a central axis of the grinding wheel 11. The edge region 41 runs on the grinding side 31 along the entire extent of the grinding wheel 11. The edge region 41 of the grinding wheel 11 is designed to be free-standing.

[0080] The grinding wheel 11 has a cover binder element 39, which covers the grinding area 21 and the free area 23. The edge area 41 is formed free of the cover binder element 39.

[0081] The edge region 41 is delimited by the grinding region 21 and by the clearance region 23. Starting from a center point or a central axis of the grinding wheel 11, the edge region 41 is delimited in the radial direction by the grinding region 21 on the one hand and by the clearance region 23 on the other hand.

[0082] The edge region 41 is delimited by a maximum diameter D1 of the grinding wheel 11 and by a distance from the diameter of less than 3 mm. The edge region 41 is designed as an edge surface formed by a diameter difference (D1 - D2) of less than 8 mm, such as 6 mm. The edge region 41 has a distance from the edge of the abrasive 11 that is essentially independent of the grinding wheel 11 used; this distance can be essentially equidistant for grinding wheels 11 with a diameter of 80 mm, but also of 170 mm.

[0083] The grinding wheel 11 has an opening 37 for extracting grinding dust. The edge region 41 is formed free of each opening 37. The edge region 41 is formed at a distance from each opening 37. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2007 / 144915 A1

[0002]

Claims

[1] Abrasive means, in particular grinding wheel, for grinding a workpiece with a, in particular flexible, carrier element (13), with a plurality of grinding elements (15) for grinding a workpiece and with a base binder element (17) for holding the grinding elements (15) on the carrier element (13), characterized by a buffer element (71) formed from an elastomer for holding the base binder element (17) and / or the grinding elements (15) on the carrier element (13). [2] Abrasive according to claim 1, characterized by that the buffer element (71) is formed from a plastic, in particular a plastic film. [3] Abrasive according to one of the preceding claims, characterized by that the buffer element (71) is arranged between the base binder element (17) and the support element (13). [4] Abrasive according to one of the preceding claims, characterized bythat the base binder element (17) is arranged on the buffer element (71). [5] Abrasive according to one of the preceding claims, characterized by a cover binder element (39) for covering the grinding element (15), the base binder element (17) and / or the buffer element (71), wherein the cover binder element (39) has a thickness (S39) which is smaller than a thickness (S71) of the buffer element (71). [6] Abrasive according to one of the preceding claims, characterized by that the carrier element (13) is formed from a plastic, in particular a plastic film. [7] Abrasive according to one of the preceding claims, characterized by that the carrier element (13) can be formed from a thermoplastic. [8] Abrasive according to one of the preceding claims, characterized by a grinding area (21) formed by means of base binder elements (17) and / or grinding elements. [9] Abrasive according to one of the preceding claims, characterized by that the grinding area (21) is formed from a plurality of base binder elements (17) arranged discretely spaced from one another. [10] Abrasive according to one of the preceding claims, characterized by that the cover binder element (39) has a hardness which is greater than a hardness of the buffer element (71).

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