Diamond grinding wheel

Abstract

A dry diamond grinding wheel for dry grinding ceramic tiles including an annular or discoidal support body configured to be fixed to a rotating spindle of a grinding machine. The support body includes a peripheral support surface supporting a diamond abrasive material, a first annular body, an outer face thereof includes the support surface supporting the diamond abrasive material and a second annular or discoidal body fixed co-axially to the first body at an inner face of the first body opposite the outer face.

Description

TECHNICAL FIELD

[0001] The present invention concerns a dry diamond grinding wheel for dry grinding ceramic tiles, specifically designed to reduce noise and improve stability during operation.PRIOR ART

[0002] As is known, grinding ceramic tiles typically involves the use of grinding wheels mounted on grinding machines. These grinding wheels are used to remove excess material from the edges or surfaces of the tiles in order to obtain precise dimensions. Conventional grinding wheels are composed of a monolithic support body made of steel or iron provided with an annular support surface on which the diamond abrasive material is formed and fixed.

[0003] The rubbing of the abrasive material on the edge of the tiles, in the process for dry grinding them, can lead to a considerable level of noise (in particular a loud noise and with a very high frequency) and vibrations during operation. This not only affects the working environment, but also reduces the accuracy and efficiency of the grinding process.

[0004] A known solution involves installing grinding machines in soundproofed chambers, but these approaches often add complexity and cost to the production process. In addition, these solutions do not adequately address noise reduction under different operating conditions, as in the same soundproofed room the operator is required to enter several times for maintenance and / or process control operations even when one or more machines are in operation.DISCLOSURE OF THE INVENTION

[0005] An object of the present invention is to overcome the drawbacks of the prior art in the context of an efficient, rational and cost-effective solution.

[0006] In particular, an object of the present invention is to provide a grinding wheel that effectively reduces noise and vibrations while dry grinding ceramic tiles, ensuring stable and efficient operation (without the use of liquid cooling or lubrication media). These objects are achieved by the features of the invention series forth in the independent claim. The dependent claims outline preferred and / or particularly advantageous aspects of the invention.

[0007] The invention, in particular, makes available a dry diamond grinding wheel for dry grinding ceramic tiles comprising:

[0008] an annular or discoidal support body configured to be fixed to a rotating spindle of a grinding machine; wherein the support body comprises a peripheral support surface supporting a diamond abrasive material,

[0009] characterized in that the support body comprises a first annular body an outer face thereof comprises the support surface supporting the diamond abrasive material and a second annular or discoidal body fixed coaxially to the first body at an inner face of the first body opposite the outer face.

[0010] This configuration ensures greater stability and noise reduction during operation. In particular, the addition of the second body (and of the discontinuity surface between the two bodies) allows to dampen the noise and vibrations of the first body, allowing the attenuation of the noise (i.e. the emission of a less loud noise in terms of intensity / dB) and / or a reduction of the emission frequency (i.e. the emission of a less sharp and more deep / low sound, i.e. less annoying).

[0011] According to one aspect of the invention, the first (monolithic) body may be made of a first metallic material, preferably steel or iron.

[0012] This choice of material gives greater durability and mechanical strength to the grinding wheel (which is subjected to strong stresses during use).

[0013] According to a further aspect of the invention, the second (monolithic) body may be made of a second metallic material different from the first metallic material, preferably having a specific weight lower than the specific weight of the first metallic material, for example aluminium.

[0014] This increases the noise reduction effect mentioned above and, at the same time, reduces the overall weight of the grinding wheel while maintaining its structural integrity (substantially with the same thickness as the known grinding wheels).

[0015] According to a preferred aspect of the invention, an intermediate (annular) body coaxially fixed to the first body and the second body (and firmly retained there-between) and configured to further abate noise and / or vibrations is interposed between the first body and the second body.

[0016] In particular, the support body can be constituted by the first body, the second body and the intermediate body interposed between them.

[0017] This intermediate body improves the acoustic damping properties of the grinding wheel.

[0018] Advantageously, the intermediate body can be made of a third metallic material different from the first material and the second material, preferably copper.

[0019] The use of an additional material, preferably copper, improves the absorption of vibrations, contributing to a quieter operation of the grinding wheel, as well as compensating for the different thermal expansions between the first body and the second body.

[0020] For example, the intermediate body may be made of a third metallic material having a specific weight greater than the specific weight of the first material.

[0021] Still, the intermediate body has a thickness less than the thickness of the first body and / or of the second body, preferably comprised between 0.1 mm and 2 mm.

[0022] Thanks to this, noise reduction is optimized without adding excessive weight to the grinding wheel.

[0023] According to an alternative aspect of the invention, the support body may be constituted by the first body and by the second body (without the interposition of the intermediate body), wherein the inner face of the first body is placed into direct forced contact with an inner face of the second body.

[0024] Even in this simplified configuration, in fact, there was a good attenuation of the noise of the grinding wheel in operation.

[0025] According to an advantageous aspect of the invention, the first body and the second body (with the possible intermediate body interposed between them) can be firmly fixed together by means of a plurality of bolts, the number of which is preferably higher than eight.

[0026] This fixing method ensures that the components remain firmly joined to each other during use, while allowing for optimal mechanical strength and optimal sound performance of the grinding wheel.

[0027] According to a further aspect of the invention, the bolts may be evenly distributed along the circumference of the first body and / or of the second body, preferably aligned along one or more concentric imaginary circumferences with respect to the first body and / or the second body.

[0028] This distribution ensures a balanced tightening force / pressure over the entire grinding wheel.

[0029] Advantageously, the adjacent bolts can be spaced from each other by an angular distance of less than or equal to 45°.

[0030] This spacing ensures even distribution of the tightening force / pressure and improves grinding wheel stability.

[0031] Preferably, the bolts can be tightened to provide a predetermined tightening force / compressive tightening pressure substantially comprised between 120 Nm and 160 Nm, preferably equal to 152 Nm.

[0032] This specific force / pressure range maintains optimal pressure without damaging / deforming the components.

[0033] Advantageously, at least one between the first body and the second body may comprise fixing holes, preferably aligned along a further concentric imaginary circumference with respect to the first body and / or the second body, for fixing the grinding wheel to the rotating spindle of the grinding machine.

[0034] This feature allows easy and safe fixing to the grinding machine.

[0035] The compound that forms the diamond abrasive material, for example, comprises a matrix (formed by (minor) abrasives, said binder, for example based on binder resins and any additives, and any fillers) to which the (main abrasive) diamond is added.

[0036] For example, the diamond abrasive material may comprise a percentage of diamond greater than or equal to 20%, preferably greater than or equal to 25% (more preferably greater than or equal to 45%), by weight with respect to the total weight of the matrix that forms the compound of diamond abrasive material and, preferably a percentage of iron and iron-derived oxides less than 20%, preferably less than or equal to 15% (more preferably less than or equal to 12%) by weight with respect to the total weight of the matrix itself.

[0037] This composition, in addition to making the grinding wheel exclusively suitable for dry grinding ceramic tiles, guarantees a high efficiency in the removal of the material and a long life of the abrasive surface.

[0038] The invention further makes available a use of a dry diamond grinding wheel, as described above, in a process for dry grinding ceramic tiles, wherein the dry diamond grinding wheel is configured to operate without the use of a liquid cooling or lubricating medium and is adapted to remove ceramic material from the edges or surfaces of the ceramic tiles during the grinding process.

[0039] In particular, the use of abrasive grinding wheels with low sound impact, especially in dry grinding processes, makes it possible to achieve the aforementioned purposes, in a process that, in addition to being preferred on the market, is efficient, cheaper and cleaner, without requiring water and other processing lubricants.

[0040] Furthermore, the invention makes available a method for manufacturing a dry diamond grinding wheel for grinding ceramic tiles (as described above), comprising the steps of:

[0041] forming a first annular or discoidal body of a support body in a first metallic material, the first body comprising a peripheral support surface for a diamond abrasive material;

[0042] forming a diamond abrasive material on the peripheral support surface of the first body;

[0043] forming a second annular or discoidal body of the support body in a second metallic material, preferably different from the first metallic material;

[0044] optionally interposing an intermediate body, preferably made of a third metallic material different from the first material and the second material, between the first body and the second body; and

[0045] tightening the first body and the second body together, preferably using a plurality of bolts, more preferably in a number greater than 8 and / or arranged circumferentially with an angular distance less than or equal to 45°.

[0046] This manufacturing method makes it possible to obtain a silenced (low sound impact) grinding wheel that is robust and effective, as well as suitable for industrial applications (especially designed for dry applications).BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Further features and advantages of the invention will be more apparent after reading the following description provided by way of a non-limiting example, with the aid of the figures illustrated in the accompanying drawings.

[0048] FIG. 1 is an exploded (rear) axonometric view of an embodiment of the grinding wheel according to the invention.

[0049] FIG. 2 is a front view of a first body of a support body of the grinding wheel according to the invention.

[0050] FIG. 3 is a view along the trace of section III-III of FIG. 2.

[0051] FIG. 4 is an enlarged view of a detail IV of FIG. 3.

[0052] FIG. 5 is a front view of a second body of a support body of the grinding wheel according to the invention.

[0053] FIG. 6 is a view along the trace of section VI-VI of FIG. 5.

[0054] FIG. 7 is an exploded (rear) axonometric view of a preferred embodiment of the grinding wheel according to the invention.

[0055] FIG. 8 is a front view of an intermediate body of a support body of the grinding wheel of FIG. 7.BEST MODE TO IMPLEMENT THE INVENTION

[0056] With particular reference to these figures, globally indicated with 10 is a dry diamond abrasive grinding wheel, i.e. for dry processing, in particular for dry grinding ceramic tiles (or other similar material, such as natural stone slabs, glass or the like).

[0057] The grinding wheel 10 comprises an annular or discoidal support body 20, provided with a central axis A, which is configured to be fixed (coaxially and removably) to a rotating spindle of a grinding machine (not illustrated as of known type).

[0058] The support body 20 may overall have a stratiform or “sandwich”-like structure.

[0059] The support body 20, in particular, comprises a first body 21 provided with a (substantially or globally) planar outer face 211 and an inner face 212 opposite the outer face 211, which may for example also be planar and, preferably, parallel to the outer face 211.

[0060] The outer face 211 and the inner face 212 are for example orthogonal to the central axis A of the support body 20 (i.e. of the first body 21).

[0061] Preferably, the first body 21 is monolithic, i.e. made in a single body.

[0062] The first body 21 is rigid, i.e. substantially non-deformable to the usual stresses to which it is subjected in operation.

[0063] The first body 21 is preferably made of a first metallic material, preferably steel or iron.

[0064] The first body 21 is constituted by (or comprises) a plate-shaped body, the thickness of which (reduced, for example equal to 1 cm±0.2 cm) is defined by the distance between the outer face 211 and the inner face 212, which define the main faces of the first body 21, i.e. of the plate-shaped body itself.

[0065] The first body 21, for example, comprises a (large) central hole and an outer (circular) perimeter edge.

[0066] The outer face 211 of the first body 21 comprises a peripheral, e.g. annular, support surface 213 which is intended to support a circular abrasive crown 30 made of a diamond abrasive material.

[0067] For example, the support surface 213 comprises one or more grooves (e.g. circumferential and concentric) configured to stably grip the circular abrasive crown 30 (which is formed and solidified thereon).

[0068] The circular abrasive crown 30 has any shape and size depending on the needs and applications required.

[0069] For example, the circular abrasive crown 30 is obtained (by pressing and / or forming and / or solidifying) from a mixture of abrasive grains supported by a binder resin (which retains the abrasive grains and causes the circular abrasive crown 30 to adhere to the support surface 213 of the outer face 211 of the first body 21.

[0070] In practice, the circular abrasive crown 30 is obtained by (pressing) a mixture or compound of loose grains of abrasive material, for example abrasive material such as diamonds and other (minor) abrasives, and mixed with an appropriate binder, for example based on binder resins and any additives and / or fillers.

[0071] The compound that forms the diamond abrasive material, for example, comprises a matrix (formed by (minor) abrasives, said binder, for example based on binder resins and any additives, and any fillers) to which the (main abrasive) diamond is added.

[0072] The compound that forms the diamond abrasive material of the circular abrasive crown 30 comprises a percentage of diamond greater than or equal to 20%, preferably greater than or equal to 25% (more preferably greater than or equal to 45%), by weight with respect to the total weight of the matrix forming the compound of diamond abrasive material.

[0073] Furthermore, the compound that forms the diamond abrasive material of the circular abrasive crown 30, i.e. the aforementioned matrix, preferably has a percentage of iron and iron-derived oxides of less than 20%, preferably less than or equal to 15% (more preferably less than or equal to 12%) by weight with respect to the total weight of the matrix itself.

[0074] The compound that forms the diamond abrasive material of the circular abrasive crown 30, i.e. the aforementioned matrix, comprises a percentage of copper or derived oxides greater than or equal to 40%, preferably 60%, by weight with respect to the total weight of the matrix itself.

[0075] On the inner face 212 there are obtained a plurality of blind threaded holes 214 (i.e. which do not pass on the outer face 211), the function of which will be described in detail below.

[0076] Advantageously, the screwing axis of the threaded holes 214 is parallel to the central axis A.

[0077] For example, the number of threaded holes 214 is preferably higher than eight.

[0078] Preferably, the threaded holes 214 are evenly distributed along the circumference of the first body 21, preferably aligned along one or more concentric imaginary circumferences with respect to the first body 21.

[0079] In the example, the threaded holes 214 are evenly distributed along the circumference of the first body 21 and, are aligned along two concentric imaginary circumferences with respect to the first body 21.

[0080] A first series of threaded holes 214 provide threaded holes 214 aligned along a first imaginary circumference centred on the central axis A and a second series of threaded holes 214 provide threaded holes 214 that are aligned along a second imaginary circumference centred on the central axis A and having a diameter greater than the first imaginary circumference.

[0081] The adjacent threaded holes 214 (of each series of threaded holes 214) are spaced from each other by an angular distance of less than or equal to 45°.

[0082] For example, the threaded holes 214 of the first series of threaded holes 214 (on the first imaginary circumference of smaller diameter) have a mutual angular distance of 22.5°.

[0083] In the example, the threaded holes 214 of the first series of threaded holes 214 (on the first imaginary circumference of smaller diameter) have diameters different from each other, in particular a first group (equal to half of the threaded holes 214) has a diameter larger than (or double) the diameter of a second group (equal to half of the threaded holes 214) of threaded holes 214 and, in addition, the threaded holes 214 of the first group are spaced from the threaded holes 214 of the second group.

[0084] Furthermore, the threaded holes 214 of the second series of threaded holes 214 (on the second imaginary circumference of larger diameter) have a mutual angular distance of 30°.

[0085] In the example, the threaded holes 214 of the second series of threaded holes 214 (on the second imaginary circumference of larger diameter) have diameters equal to each other.

[0086] It is not excluded that the threaded holes 214 have a different conformation / arrangement with respect to the one described and illustrated above.

[0087] The support body 20 further comprises a second body 22 provided with a (substantially or globally) planar outer face 221 and an inner face 222 opposite the outer face 221, which may for example also be planar and, preferably, parallel to the outer face 211.

[0088] It is not excluded that one or both faces 221,222 of the second body—as illustrated—have at least one annular step (concentric to the central axis A).

[0089] The outer face 221 and the inner face 222 are for example globally orthogonal to the central axis A of the support body 20 (i.e. of the second body 22).

[0090] Preferably, the second body 22 is monolithic, i.e. made in a single body.

[0091] The second body 22 is rigid, i.e. substantially non-deformable to the usual stresses to which it is subjected in operation.

[0092] The second body 22 is preferably made of a second metallic material, preferably different from the first metallic material of which the first body 21 is made (although it is not excluded that in certain applications it is possible to make the second body 22 of the same material, for example metallic, of which the first body 21 is made). For example, the second metallic material of which the second body 22 is made has a specific weight lower than the specific weight of the first metallic material of which the first body 21 is made.

[0093] Preferably (but not in a limiting manner), the second metallic material of which the second body 22 is made is aluminium.

[0094] The second body 22 is constituted by (or comprises) a plate-shaped body, the thickness of which (reduced, for example equal to 1.95 cm +0.2 cm) is defined by the maximum distance between the outer face 221 and the inner face 222, which define the main faces of the second body 22, i.e. of the plate-shaped body itself. The second body 22, for example, comprises a central hole (of smaller or equal diameter with respect to the central hole of the first body 21) and an outer (circular) perimeter edge, having an outer diameter equal to the outer diameter of the perimeter edge of the first body 21.

[0095] On the second body 22 there are obtained a plurality of through holes 224 (i.e. which pass from side to side, in the direction of thickness, from the outer face 221 to the inner face 222), the function of which will be described in detail below.

[0096] Advantageously, the through axis of the holes 224 is parallel to the central axis A. For example, the number of holes 224 is preferably higher than eight.

[0097] Preferably, the holes 224 are evenly distributed along the circumference of the second body 22, preferably aligned along one or more concentric imaginary circumferences with respect to the second body 22.

[0098] In the example, the holes 224 are evenly distributed along the circumference of the second body 22 and, are aligned along two concentric imaginary circumferences with respect to the second body 22.

[0099] A first series of holes 224 provide holes 224 aligned along a first imaginary circumference centred on the central axis A and a second series of holes 224 provide holes 224 that are aligned along a second imaginary circumference centred on the central axis A and having a diameter greater than the first imaginary circumference. The adjacent holes 224 (of each series of holes 224) are spaced from each other by an angular distance of less than or equal to 45°.

[0100] For example, the holes 224 of the first series of holes 224 (on the first imaginary circumference of smaller diameter) have a mutual angular distance of 22.5°.

[0101] In the example, the holes 224 of the first series of holes 224 (on the first imaginary circumference of smaller diameter) have diameters different from each other, in particular a first group (equal to half of the holes 224) has a diameter larger than (or double) the diameter of a second group (equal to half of the holes 224) of holes 224 and, in addition, the holes 224 of the first group are spaced from the holes 224 of the second group.

[0102] Furthermore, the holes 224 of the second series of holes 224 (on the second imaginary circumference of larger diameter) have a mutual angular distance of 30°. In the example, the holes 224 of the second series of holes 224 (on the second imaginary larger diameter circumference) have diameters equal to each other.

[0103] It is not excluded that the holes 224 have a different conformation / arrangement with respect to the one described and illustrated above.

[0104] In the example, the holes 224 are made in an outer peripheral circular crown of the second body 22, the shape (inner diameter and outer diameter) of which is homologous to the (overall) shape of the first body 21.

[0105] Preferably, each hole 224 of the second body 22 is configured to be coaxially aligned (in use) with a respective (and homologous, at least in terms of diameter) threaded hole 214 of the first body 21 and / or each threaded hole 214 of the first body 21 is configured to be coaxially aligned with a respective (and homologous, at least in terms of diameter) hole 224 of the second body 22.

[0106] Furthermore, for example, each hole 224 or a plurality of them has a conical lead-in section, for example at the end segment thereof that emerges at the outer face 221.

[0107] In the example, the second body 22 has a central zone (which is separated from the aforementioned outer peripheral circular crown by an annular step and, for example, has an increased thickness with respect to the thickness of the outer peripheral circular crown).

[0108] Preferably, this central (annular) zone acts as an attachment plate for the grinding wheel 10 to the spindle of the grinding machine (if necessary).

[0109] For this purpose, the second body 22, in said central zone, comprises a plurality of further attachment holes 225, for example through holes.

[0110] For example, the through axis of the attachment holes 225 is parallel to the central axis A.

[0111] For example, the number of attachment holes 225 is preferably equal to or higher than four.

[0112] Preferably, the attachment holes 225 are evenly distributed along the circumference of the central zone of the second body 22, preferably aligned along one or more concentric imaginary circumferences with respect to the second body 22.

[0113] In the example, the attachment holes 225 are evenly distributed along the circumference of the second body 22 and, are aligned along two concentric imaginary circumferences with respect to the second body 22.

[0114] A first series of (four) attachment holes 225 provide attachment holes 225 aligned along a first imaginary circumference centred on the central axis A and a second series of (four) attachment holes 225 provide attachment holes 225 that are aligned along a second imaginary circumference centred on the central axis A and having a diameter larger than the first imaginary circumference.

[0115] The adjacent attachment holes 225 (of each series of attachment holes 225) are spaced from each other by an angular distance equal to 90°.

[0116] The support body 20 comprises fixing members that joins (coaxially) the first body 21 and the second body 22.

[0117] The fixing members, in practice, join the second body 22 rearwardly to the first body 21, i.e. at its inner face 212 (opposite the outer face that supports the circular abrasive crown 30).

[0118] The fixing members comprise or are constituted by a plurality of bolts 40, the number of which is preferably higher than eight.

[0119] The plurality of bolts 40 are configured to clamp the first body 21 and the second body 22.

[0120] Each bolt 40 of the plurality of bolts 40 is configured to be inserted (from the side of the outer face 221 of the second body 22) into a respective hole 224 of the second body 22 and screwed into a respective (coaxial) threaded hole 214 of the first body 21.

[0121] Each bolt 40 is, in practice, concealedly connected within the thickness of the support body 20 (i.e. its head is recessed or flush with the outer face 221 of the second body 22).

[0122] In practice, the bolts 40 (which occupy-preferably all-the holes 224 and the threaded holes 214) are evenly distributed along the circumference of the first body 21 and / or of the second body 22, preferably aligned along the aforementioned imaginary circumference(s).

[0123] In practice, the adjacent bolts 40 are spaced from each other by an angular distance of less than or equal to 45°.

[0124] In more detail, the bolts 40 that occupy (to size) the first series of holes 224 and are screwed to the first series of threaded holes 214 have a mutual angular distance of 22.5°.

[0125] Furthermore, the bolts 40 that occupy (to size) the second series of holes 224 and are screwed to the second series of threaded holes 214 have a mutual angular distance of 30°.

[0126] The bolts 40 are tightened to provide a predetermined compressive tightening force / pressure between the first body 21 and the second body 22 substantially comprised between 120 Nm and 160 Nm, preferably equal to 152 Nm.

[0127] For example, each bolt 40 is tightened with a tightening torque greater than or equal to 6 Nm, for example comprised between 6 Nm and 8 Nm, preferably equal to 7.6 Nm).

[0128] Advantageously, the fixing means may—further—comprise anti-unscrewing means of the bolts 40 and / or of each bolt 40, for example configured to prevent / hinder the involuntary unscrewing thereof.

[0129] Preferably, the anti-unscrewing means comprise (or are constituted by) a thread-locker glue / adhesive (for each bolt 40), such as for example Locktite or the like.

[0130] Alternatively or in addition to the above, the fixing members may be of the glue or welding type or other fixing technique such as to allow (removable or permanent) fixing between the first body 21 and the second body 22, for example in this case the fixing members may comprise or be constituted by a layer of glue interposed between the inner face 212 of the first body 21 and the inner face 222 of the second body 22.

[0131] In a simplified embodiment of the invention illustrated in FIG. 1, the support body 20 is constituted exclusively (except for the fixing members) by the first body 21 and by the second body 22, coaxially associated so that the inner face 212 of the first body 21 is placed in (close) direct and forced contact with the inner face 222 of the second body 22.

[0132] In particular, the inner face 212 of the first body 21 is fully in contact with an annular portion of the (outer peripheral circular crown) of the inner face 222 of the second body 22.

[0133] In a further and preferred embodiment shown in FIG. 6, between the first body 21 and the second body 22, i.e. between the inner face 212 of the first body 21 and the inner face 222 of the second body 22, an intermediate (annular) body 23 is interposed coaxially fixed to the first body 21 and to the second body 22.

[0134] The intermediate body 23 is configured to further abate noise and / or vibrations of the grinding wheel 10.

[0135] In practice, the intermediate body 23 has a damper and / or attenuator function.

[0136] The intermediate body 23 is provided with a first (substantially or globally) planar face 231 and a second face 232 opposite the first face 231, which may for example also be planar and, preferably, parallel to the first face 231.

[0137] The first face 231 and the second face 232 are for example orthogonal to the central axis A of the support body 20 (i.e. of the intermediate body 23).

[0138] Preferably, the intermediate body 23 is monolithic, i.e. made in a single body.

[0139] The intermediate body 23 is for example rigid, i.e. substantially non-deformable, at least under compression, to the usual stresses to which it is subjected in operation. The intermediate body 23 is preferably made of a third metallic material, preferably different from the first material and the second material.

[0140] For example, the third metallic material of which the intermediate body 23 is made has a specific weight greater than the specific weight of the first metallic material of which the first body 21 is made.

[0141] For example, the third metallic material of which the intermediate body 23 is made is copper.

[0142] The intermediate body 23 is constituted by (or comprises) a plate-shaped body, the thickness of which is defined by the distance between the first face 231 and the second face 232, which define the main faces of the intermediate body 23, i.e. of the plate-shaped body itself.

[0143] The intermediate body 23 has a thickness less than the thickness of the first body 21 and / or of the second body 22, preferably comprised between 0.1 mm and 2 mm, more preferably equal to 0.3 mm + / −0.05 mm.

[0144] The intermediate body 233, for example, comprises a (wide) central hole and an outer (circular) perimeter edge.

[0145] The dimensions (outer diameter and inner diameter) of the intermediate body 23—except for the thickness—are similar or preferably identical to those of the first body 21.

[0146] On the intermediate body 23 there are obtained a plurality of further through holes 234 (i.e. which pass from side to side, in the direction of thickness, from the first face 231 to the second face 232).

[0147] Advantageously, the through axis of the further holes 234 is parallel to the central axis A.

[0148] For example, the number of the further holes 234 is preferably higher than eight. Preferably, the further holes 234 are evenly distributed along the circumference of the intermediate body 23, preferably aligned along one or more concentric imaginary circumferences with respect to the intermediate body 23.

[0149] In the example, the further holes 234 are evenly distributed along the circumference of the intermediate body 23 and, are aligned along two concentric imaginary circumferences with respect to the intermediate body 23.

[0150] A first series of further holes 234 provide further holes 234 aligned along a first imaginary circumference centred on the central axis A and a second series of further holes 234 provide further holes 234 that are aligned along a second imaginary circumference centred on the central axis A and having a diameter greater than the first imaginary circumference.

[0151] The further adjacent holes 234 (of each series of further holes 234) are spaced from each other by an angular distance of less than or equal to 45°.

[0152] For example, the further holes 234 of the first series of holes 234 (on the first imaginary circumference of smaller diameter) have a mutual angular distance of 22.5°.

[0153] In the example, the further holes 234 of the first series of holes 234 (on the first imaginary circumference of smaller diameter) have diameters different from each other, in particular a first group (equal to half of the further holes 234) has a diameter larger than (or double) the diameter of a second group (equal to half of the further holes 234) of holes 234 and, in addition, the holes 234 of the first group are spaced from the holes 234 of the second group.

[0154] Furthermore, the further holes 234 of the second series of holes 234 (on the second imaginary circumference of larger diameter) have a mutual angular distance of 30°. In the example, the further holes 234 of the second series of holes 234 (on the second imaginary circumference of larger diameter) have diameters equal to each other.

[0155] It is not excluded that the further holes 234 have a different conformation / arrangement with respect to the one described and illustrated above.

[0156] In this preferred embodiment, the intermediate layer 23 is (forcibly) clamped between the first body 21 and the second body 22.

[0157] For example, the support body 20 is constituted exclusively (except for the fixing members) by the first body 21, the (only) intermediate body 23 and the second body 22, coaxially associated so that:

[0158] the inner face 212 of the first body 21 is placed in (close) direct and forced contact with one between the first face 231 and the second face 232 of the intermediate body 23 (in the example to the first face 231) and

[0159] the inner face 222 of the second body 22 is placed in (close) direct and forced contact to the other between the second face 232 and the first face 231 of the intermediate body 23 (in the example to the second face 232).

[0160] In particular, the entire inner face 212 of the first body 21 is fully in contact with the (entire) first face 231 of the intermediate body 23 and an annular portion of the (outer peripheral circular crown) of the inner face 222 of the second body 22 is fully in contact with the (entire) second face 232 of the intermediate body 23.

[0161] Also in this case, the fixing members comprise or are constituted by a plurality of bolts 40, the number of which is preferably higher than eight.

[0162] The plurality of bolts 40 is configured to clamp the first body 21 and the second body 22, with the intermediate body 23 interposed therebetween.

[0163] Each bolt 40 of the plurality of bolts 40 is configured to be inserted (from the side of the outer face 221 of the second body 22) into a respective hole 224 of the second body 22, into a corresponding further coaxial hole 234 of the intermediate body 23 and screwed into a respective (coaxial) threaded hole 214 of the first body 21.

[0164] Each bolt 40 is, in practice, concealedly connected within the thickness of the support body 20 (i.e. its head is recessed or flush with the outer face 221 of the second body 22).

[0165] In practice, the bolts 40 (which occupy-preferably all-the holes 224, the further holes 234 and the threaded holes 214) are evenly distributed along the circumference of the first body 21 and / or of the second body 22 and / or of the intermediate body 23, preferably aligned along the aforesaid imaginary circumference(s) (with the aforesaid angular distances and spatial arrangements).

[0166] The bolts 40 are tightened to provide a predetermined compressive tightening force / pressure between the first body 21 and the second body 22 and the intermediate body 23 substantially comprised between 120 Nm and 160 Nm, preferably equal to 152 Nm.

[0167] For example, each bolt 40 is tightened with a tightening torque greater than or equal to 6 Nm, for example comprised between 6 Nm and 8 Nm, preferably equal to 7.6 Nm).

[0168] Also in this case, the fixing means may further comprise anti-unscrewing means of the bolts 40 and / or of each bolt 40, for example configured to prevent / hinder the involuntary unscrewing thereof.

[0169] Preferably, the anti-unscrewing means comprise (or are constituted by) a thread-locker glue / adhesive (for each bolt 40), such as for example Locktite or the like.

[0170] Alternatively or in addition to the above, the fixing members may be of the glue or welding type or other fixing technique such as to allow (removable or permanent) fixing between the first body 21, the intermediate body 23 and the second body 22, for example in this case the fixing members may comprise or be constituted by a first layer of glue interposed between the inner face 212 of the first body 21 and the first face 231 of the intermediate body 23 and a second layer of glue interposed between the inner face 222 of the second body 22 and the second face 232 of the intermediate body 23.

[0171] The support body 20, thus formed, is adapted to be installed coaxially-by means of appropriate tightening bolts-to the rotating spindle of a grinding machine or other machine suitable for processing ceramic tiles or the like, for the execution of the squaring or grinding processing thereof and / or other suitable processing.

[0172] It is also not excluded that the support body 20 can be formed by joining more than two (or three) annular bodies, wherein the sandwich-like structure described above is formed by more layers than those of the structures described above.

[0173] A preferred use of such a grinding wheel 10 is the use in a process for dry grinding / squaring ceramic tiles (i.e. a process that does not involve the use of cooling media or liquid lubricants or water) and is suitable for removing ceramic material from the edges or from the surfaces of ceramic tiles during the grinding / squaring process.

[0174] The aforementioned grinding wheel 10 is made by means of a manufacturing method comprising the steps of:

[0175] forming, for example by casting and / or mechanical machining, the first annular or discoidal body 21;

[0176] forming, by pressing and / or other suitable forming technique, a diamond abrasive material on the peripheral support surface 213 of the first body 21;

[0177] forming, for example by casting and / or mechanical machining, the second annular or discoidal body 22;

[0178] optionally forming, by cutting a sheet, an intermediate body 23 and interposing the intermediate body 23, between the first body 21 and the second body 23; and

[0179] tightening the first body 21 and the second body 22 together, preferably using the aforementioned plurality of bolts 40 (and applying the aforementioned tightening force).

[0180] It has been observed that, when the grinding wheel 10—thus made—is in use (and the circular abrasive crown 30 rubs against the ceramic tiles or other material to be worked), thanks to the structural discontinuity between the first body 21 and the second body 22—and / or, even more, thanks to the presence of the intermediate body 23 that accentuates this discontinuity mechanically and / or physically—, the sound emitted by this grinding wheel 10 is decidedly more attenuated (in terms of sound intensity and / or in terms of frequency of sound emission / vibration), compared to traditional grinding wheels in which the support bodies are monolithic, allowing a reduction in the sound emission and discomfort of the grinding wheel itself.

[0181] In particular, a reduction of the sound intensity by 3-10 dB (for example by 5-7 dB) was observed, for each grinding wheel 10 and / or in the total number of grinding wheels 10 used in a grinding machine.

[0182] In addition, for example, a (considerable) attenuation of the emission frequency was observed (which switches from a sharp sound—“Grima”—to a deep sound). The invention thus conceived is susceptible to many modifications and variants, all falling within the same inventive concept.

[0183] Moreover, all details can be replaced by other technically equivalent elements.

[0184] In practice, the materials used, as well as the contingent shapes and sizes, can be whatever according to the requirements without for this reason departing from the scope of protection of the following claims.

Examples

Embodiment Construction

[0056]With particular reference to these figures, globally indicated with 10 is a dry diamond abrasive grinding wheel, i.e. for dry processing, in particular for dry grinding ceramic tiles (or other similar material, such as natural stone slabs, glass or the like).

[0057]The grinding wheel 10 comprises an annular or discoidal support body 20, provided with a central axis A, which is configured to be fixed (coaxially and removably) to a rotating spindle of a grinding machine (not illustrated as of known type).

[0058]The support body 20 may overall have a stratiform or “sandwich”-like structure.

[0059]The support body 20, in particular, comprises a first body 21 provided with a (substantially or globally) planar outer face 211 and an inner face 212 opposite the outer face 211, which may for example also be planar and, preferably, parallel to the outer face 211.

[0060]The outer face 211 and the inner face 212 are for example orthogonal to the central axis A of the support body 20 (i.e. of ...

TECHNICAL FIELD

[0001] The present invention concerns a dry diamond grinding wheel for dry grinding ceramic tiles, specifically designed to reduce noise and improve stability during operation.PRIOR ART

[0002] As is known, grinding ceramic tiles typically involves the use of grinding wheels mounted on grinding machines. These grinding wheels are used to remove excess material from the edges or surfaces of the tiles in order to obtain precise dimensions. Conventional grinding wheels are composed of a monolithic support body made of steel or iron provided with an annular support surface on which the diamond abrasive material is formed and fixed.

[0003] The rubbing of the abrasive material on the edge of the tiles, in the process for dry grinding them, can lead to a considerable level of noise (in particular a loud noise and with a very high frequency) and vibrations during operation. This not only affects the working environment, but also reduces the accuracy and efficiency of the grinding process.

[0004] A known solution involves installing grinding machines in soundproofed chambers, but these approaches often add complexity and cost to the production process. In addition, these solutions do not adequately address noise reduction under different operating conditions, as in the same soundproofed room the operator is required to enter several times for maintenance and / or process control operations even when one or more machines are in operation.DISCLOSURE OF THE INVENTION

[0005] An object of the present invention is to overcome the drawbacks of the prior art in the context of an efficient, rational and cost-effective solution.

[0006] In particular, an object of the present invention is to provide a grinding wheel that effectively reduces noise and vibrations while dry grinding ceramic tiles, ensuring stable and efficient operation (without the use of liquid cooling or lubrication media). These objects are achieved by the features of the invention series forth in the independent claim. The dependent claims outline preferred and / or particularly advantageous aspects of the invention.

[0007] The invention, in particular, makes available a dry diamond grinding wheel for dry grinding ceramic tiles comprising:

[0008] an annular or discoidal support body configured to be fixed to a rotating spindle of a grinding machine; wherein the support body comprises a peripheral support surface supporting a diamond abrasive material,

[0009] characterized in that the support body comprises a first annular body an outer face thereof comprises the support surface supporting the diamond abrasive material and a second annular or discoidal body fixed coaxially to the first body at an inner face of the first body opposite the outer face.

[0010] This configuration ensures greater stability and noise reduction during operation. In particular, the addition of the second body (and of the discontinuity surface between the two bodies) allows to dampen the noise and vibrations of the first body, allowing the attenuation of the noise (i.e. the emission of a less loud noise in terms of intensity / dB) and / or a reduction of the emission frequency (i.e. the emission of a less sharp and more deep / low sound, i.e. less annoying).

[0011] According to one aspect of the invention, the first (monolithic) body may be made of a first metallic material, preferably steel or iron.

[0012] This choice of material gives greater durability and mechanical strength to the grinding wheel (which is subjected to strong stresses during use).

[0013] According to a further aspect of the invention, the second (monolithic) body may be made of a second metallic material different from the first metallic material, preferably having a specific weight lower than the specific weight of the first metallic material, for example aluminium.

[0014] This increases the noise reduction effect mentioned above and, at the same time, reduces the overall weight of the grinding wheel while maintaining its structural integrity (substantially with the same thickness as the known grinding wheels).

[0015] According to a preferred aspect of the invention, an intermediate (annular) body coaxially fixed to the first body and the second body (and firmly retained there-between) and configured to further abate noise and / or vibrations is interposed between the first body and the second body.

[0016] In particular, the support body can be constituted by the first body, the second body and the intermediate body interposed between them.

[0017] This intermediate body improves the acoustic damping properties of the grinding wheel.

[0018] Advantageously, the intermediate body can be made of a third metallic material different from the first material and the second material, preferably copper.

[0019] The use of an additional material, preferably copper, improves the absorption of vibrations, contributing to a quieter operation of the grinding wheel, as well as compensating for the different thermal expansions between the first body and the second body.

[0020] For example, the intermediate body may be made of a third metallic material having a specific weight greater than the specific weight of the first material.

[0021] Still, the intermediate body has a thickness less than the thickness of the first body and / or of the second body, preferably comprised between 0.1 mm and 2 mm.

[0022] Thanks to this, noise reduction is optimized without adding excessive weight to the grinding wheel.

[0023] According to an alternative aspect of the invention, the support body may be constituted by the first body and by the second body (without the interposition of the intermediate body), wherein the inner face of the first body is placed into direct forced contact with an inner face of the second body.

[0024] Even in this simplified configuration, in fact, there was a good attenuation of the noise of the grinding wheel in operation.

[0025] According to an advantageous aspect of the invention, the first body and the second body (with the possible intermediate body interposed between them) can be firmly fixed together by means of a plurality of bolts, the number of which is preferably higher than eight.

[0026] This fixing method ensures that the components remain firmly joined to each other during use, while allowing for optimal mechanical strength and optimal sound performance of the grinding wheel.

[0027] According to a further aspect of the invention, the bolts may be evenly distributed along the circumference of the first body and / or of the second body, preferably aligned along one or more concentric imaginary circumferences with respect to the first body and / or the second body.

[0028] This distribution ensures a balanced tightening force / pressure over the entire grinding wheel.

[0029] Advantageously, the adjacent bolts can be spaced from each other by an angular distance of less than or equal to 45°.

[0030] This spacing ensures even distribution of the tightening force / pressure and improves grinding wheel stability.

[0031] Preferably, the bolts can be tightened to provide a predetermined tightening force / compressive tightening pressure substantially comprised between 120 Nm and 160 Nm, preferably equal to 152 Nm.

[0032] This specific force / pressure range maintains optimal pressure without damaging / deforming the components.

[0033] Advantageously, at least one between the first body and the second body may comprise fixing holes, preferably aligned along a further concentric imaginary circumference with respect to the first body and / or the second body, for fixing the grinding wheel to the rotating spindle of the grinding machine.

[0034] This feature allows easy and safe fixing to the grinding machine.

[0035] The compound that forms the diamond abrasive material, for example, comprises a matrix (formed by (minor) abrasives, said binder, for example based on binder resins and any additives, and any fillers) to which the (main abrasive) diamond is added.

[0036] For example, the diamond abrasive material may comprise a percentage of diamond greater than or equal to 20%, preferably greater than or equal to 25% (more preferably greater than or equal to 45%), by weight with respect to the total weight of the matrix that forms the compound of diamond abrasive material and, preferably a percentage of iron and iron-derived oxides less than 20%, preferably less than or equal to 15% (more preferably less than or equal to 12%) by weight with respect to the total weight of the matrix itself.

[0037] This composition, in addition to making the grinding wheel exclusively suitable for dry grinding ceramic tiles, guarantees a high efficiency in the removal of the material and a long life of the abrasive surface.

[0038] The invention further makes available a use of a dry diamond grinding wheel, as described above, in a process for dry grinding ceramic tiles, wherein the dry diamond grinding wheel is configured to operate without the use of a liquid cooling or lubricating medium and is adapted to remove ceramic material from the edges or surfaces of the ceramic tiles during the grinding process.

[0039] In particular, the use of abrasive grinding wheels with low sound impact, especially in dry grinding processes, makes it possible to achieve the aforementioned purposes, in a process that, in addition to being preferred on the market, is efficient, cheaper and cleaner, without requiring water and other processing lubricants.

[0040] Furthermore, the invention makes available a method for manufacturing a dry diamond grinding wheel for grinding ceramic tiles (as described above), comprising the steps of:

[0041] forming a first annular or discoidal body of a support body in a first metallic material, the first body comprising a peripheral support surface for a diamond abrasive material;

[0042] forming a diamond abrasive material on the peripheral support surface of the first body;

[0043] forming a second annular or discoidal body of the support body in a second metallic material, preferably different from the first metallic material;

[0044] optionally interposing an intermediate body, preferably made of a third metallic material different from the first material and the second material, between the first body and the second body; and

[0045] tightening the first body and the second body together, preferably using a plurality of bolts, more preferably in a number greater than 8 and / or arranged circumferentially with an angular distance less than or equal to 45°.

[0046] This manufacturing method makes it possible to obtain a silenced (low sound impact) grinding wheel that is robust and effective, as well as suitable for industrial applications (especially designed for dry applications).BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Further features and advantages of the invention will be more apparent after reading the following description provided by way of a non-limiting example, with the aid of the figures illustrated in the accompanying drawings.

[0048] FIG. 1 is an exploded (rear) axonometric view of an embodiment of the grinding wheel according to the invention.

[0049] FIG. 2 is a front view of a first body of a support body of the grinding wheel according to the invention.

[0050] FIG. 3 is a view along the trace of section III-III of FIG. 2.

[0051] FIG. 4 is an enlarged view of a detail IV of FIG. 3.

[0052] FIG. 5 is a front view of a second body of a support body of the grinding wheel according to the invention.

[0053] FIG. 6 is a view along the trace of section VI-VI of FIG. 5.

[0054] FIG. 7 is an exploded (rear) axonometric view of a preferred embodiment of the grinding wheel according to the invention.

[0055] FIG. 8 is a front view of an intermediate body of a support body of the grinding wheel of FIG. 7.BEST MODE TO IMPLEMENT THE INVENTION

[0056] With particular reference to these figures, globally indicated with 10 is a dry diamond abrasive grinding wheel, i.e. for dry processing, in particular for dry grinding ceramic tiles (or other similar material, such as natural stone slabs, glass or the like).

[0057] The grinding wheel 10 comprises an annular or discoidal support body 20, provided with a central axis A, which is configured to be fixed (coaxially and removably) to a rotating spindle of a grinding machine (not illustrated as of known type).

[0058] The support body 20 may overall have a stratiform or “sandwich”-like structure.

[0059] The support body 20, in particular, comprises a first body 21 provided with a (substantially or globally) planar outer face 211 and an inner face 212 opposite the outer face 211, which may for example also be planar and, preferably, parallel to the outer face 211.

[0060] The outer face 211 and the inner face 212 are for example orthogonal to the central axis A of the support body 20 (i.e. of the first body 21).

[0061] Preferably, the first body 21 is monolithic, i.e. made in a single body.

[0062] The first body 21 is rigid, i.e. substantially non-deformable to the usual stresses to which it is subjected in operation.

[0063] The first body 21 is preferably made of a first metallic material, preferably steel or iron.

[0064] The first body 21 is constituted by (or comprises) a plate-shaped body, the thickness of which (reduced, for example equal to 1 cm±0.2 cm) is defined by the distance between the outer face 211 and the inner face 212, which define the main faces of the first body 21, i.e. of the plate-shaped body itself.

[0065] The first body 21, for example, comprises a (large) central hole and an outer (circular) perimeter edge.

[0066] The outer face 211 of the first body 21 comprises a peripheral, e.g. annular, support surface 213 which is intended to support a circular abrasive crown 30 made of a diamond abrasive material.

[0067] For example, the support surface 213 comprises one or more grooves (e.g. circumferential and concentric) configured to stably grip the circular abrasive crown 30 (which is formed and solidified thereon).

[0068] The circular abrasive crown 30 has any shape and size depending on the needs and applications required.

[0069] For example, the circular abrasive crown 30 is obtained (by pressing and / or forming and / or solidifying) from a mixture of abrasive grains supported by a binder resin (which retains the abrasive grains and causes the circular abrasive crown 30 to adhere to the support surface 213 of the outer face 211 of the first body 21.

[0070] In practice, the circular abrasive crown 30 is obtained by (pressing) a mixture or compound of loose grains of abrasive material, for example abrasive material such as diamonds and other (minor) abrasives, and mixed with an appropriate binder, for example based on binder resins and any additives and / or fillers.

[0071] The compound that forms the diamond abrasive material, for example, comprises a matrix (formed by (minor) abrasives, said binder, for example based on binder resins and any additives, and any fillers) to which the (main abrasive) diamond is added.

[0072] The compound that forms the diamond abrasive material of the circular abrasive crown 30 comprises a percentage of diamond greater than or equal to 20%, preferably greater than or equal to 25% (more preferably greater than or equal to 45%), by weight with respect to the total weight of the matrix forming the compound of diamond abrasive material.

[0073] Furthermore, the compound that forms the diamond abrasive material of the circular abrasive crown 30, i.e. the aforementioned matrix, preferably has a percentage of iron and iron-derived oxides of less than 20%, preferably less than or equal to 15% (more preferably less than or equal to 12%) by weight with respect to the total weight of the matrix itself.

[0074] The compound that forms the diamond abrasive material of the circular abrasive crown 30, i.e. the aforementioned matrix, comprises a percentage of copper or derived oxides greater than or equal to 40%, preferably 60%, by weight with respect to the total weight of the matrix itself.

[0075] On the inner face 212 there are obtained a plurality of blind threaded holes 214 (i.e. which do not pass on the outer face 211), the function of which will be described in detail below.

[0076] Advantageously, the screwing axis of the threaded holes 214 is parallel to the central axis A.

[0077] For example, the number of threaded holes 214 is preferably higher than eight.

[0078] Preferably, the threaded holes 214 are evenly distributed along the circumference of the first body 21, preferably aligned along one or more concentric imaginary circumferences with respect to the first body 21.

[0079] In the example, the threaded holes 214 are evenly distributed along the circumference of the first body 21 and, are aligned along two concentric imaginary circumferences with respect to the first body 21.

[0080] A first series of threaded holes 214 provide threaded holes 214 aligned along a first imaginary circumference centred on the central axis A and a second series of threaded holes 214 provide threaded holes 214 that are aligned along a second imaginary circumference centred on the central axis A and having a diameter greater than the first imaginary circumference.

[0081] The adjacent threaded holes 214 (of each series of threaded holes 214) are spaced from each other by an angular distance of less than or equal to 45°.

[0082] For example, the threaded holes 214 of the first series of threaded holes 214 (on the first imaginary circumference of smaller diameter) have a mutual angular distance of 22.5°.

[0083] In the example, the threaded holes 214 of the first series of threaded holes 214 (on the first imaginary circumference of smaller diameter) have diameters different from each other, in particular a first group (equal to half of the threaded holes 214) has a diameter larger than (or double) the diameter of a second group (equal to half of the threaded holes 214) of threaded holes 214 and, in addition, the threaded holes 214 of the first group are spaced from the threaded holes 214 of the second group.

[0084] Furthermore, the threaded holes 214 of the second series of threaded holes 214 (on the second imaginary circumference of larger diameter) have a mutual angular distance of 30°.

[0085] In the example, the threaded holes 214 of the second series of threaded holes 214 (on the second imaginary circumference of larger diameter) have diameters equal to each other.

[0086] It is not excluded that the threaded holes 214 have a different conformation / arrangement with respect to the one described and illustrated above.

[0087] The support body 20 further comprises a second body 22 provided with a (substantially or globally) planar outer face 221 and an inner face 222 opposite the outer face 221, which may for example also be planar and, preferably, parallel to the outer face 211.

[0088] It is not excluded that one or both faces 221,222 of the second body—as illustrated—have at least one annular step (concentric to the central axis A).

[0089] The outer face 221 and the inner face 222 are for example globally orthogonal to the central axis A of the support body 20 (i.e. of the second body 22).

[0090] Preferably, the second body 22 is monolithic, i.e. made in a single body.

[0091] The second body 22 is rigid, i.e. substantially non-deformable to the usual stresses to which it is subjected in operation.

[0092] The second body 22 is preferably made of a second metallic material, preferably different from the first metallic material of which the first body 21 is made (although it is not excluded that in certain applications it is possible to make the second body 22 of the same material, for example metallic, of which the first body 21 is made). For example, the second metallic material of which the second body 22 is made has a specific weight lower than the specific weight of the first metallic material of which the first body 21 is made.

[0093] Preferably (but not in a limiting manner), the second metallic material of which the second body 22 is made is aluminium.

[0094] The second body 22 is constituted by (or comprises) a plate-shaped body, the thickness of which (reduced, for example equal to 1.95 cm +0.2 cm) is defined by the maximum distance between the outer face 221 and the inner face 222, which define the main faces of the second body 22, i.e. of the plate-shaped body itself. The second body 22, for example, comprises a central hole (of smaller or equal diameter with respect to the central hole of the first body 21) and an outer (circular) perimeter edge, having an outer diameter equal to the outer diameter of the perimeter edge of the first body 21.

[0095] On the second body 22 there are obtained a plurality of through holes 224 (i.e. which pass from side to side, in the direction of thickness, from the outer face 221 to the inner face 222), the function of which will be described in detail below.

[0096] Advantageously, the through axis of the holes 224 is parallel to the central axis A. For example, the number of holes 224 is preferably higher than eight.

[0097] Preferably, the holes 224 are evenly distributed along the circumference of the second body 22, preferably aligned along one or more concentric imaginary circumferences with respect to the second body 22.

[0098] In the example, the holes 224 are evenly distributed along the circumference of the second body 22 and, are aligned along two concentric imaginary circumferences with respect to the second body 22.

[0099] A first series of holes 224 provide holes 224 aligned along a first imaginary circumference centred on the central axis A and a second series of holes 224 provide holes 224 that are aligned along a second imaginary circumference centred on the central axis A and having a diameter greater than the first imaginary circumference. The adjacent holes 224 (of each series of holes 224) are spaced from each other by an angular distance of less than or equal to 45°.

[0100] For example, the holes 224 of the first series of holes 224 (on the first imaginary circumference of smaller diameter) have a mutual angular distance of 22.5°.

[0101] In the example, the holes 224 of the first series of holes 224 (on the first imaginary circumference of smaller diameter) have diameters different from each other, in particular a first group (equal to half of the holes 224) has a diameter larger than (or double) the diameter of a second group (equal to half of the holes 224) of holes 224 and, in addition, the holes 224 of the first group are spaced from the holes 224 of the second group.

[0102] Furthermore, the holes 224 of the second series of holes 224 (on the second imaginary circumference of larger diameter) have a mutual angular distance of 30°. In the example, the holes 224 of the second series of holes 224 (on the second imaginary larger diameter circumference) have diameters equal to each other.

[0103] It is not excluded that the holes 224 have a different conformation / arrangement with respect to the one described and illustrated above.

[0104] In the example, the holes 224 are made in an outer peripheral circular crown of the second body 22, the shape (inner diameter and outer diameter) of which is homologous to the (overall) shape of the first body 21.

[0105] Preferably, each hole 224 of the second body 22 is configured to be coaxially aligned (in use) with a respective (and homologous, at least in terms of diameter) threaded hole 214 of the first body 21 and / or each threaded hole 214 of the first body 21 is configured to be coaxially aligned with a respective (and homologous, at least in terms of diameter) hole 224 of the second body 22.

[0106] Furthermore, for example, each hole 224 or a plurality of them has a conical lead-in section, for example at the end segment thereof that emerges at the outer face 221.

[0107] In the example, the second body 22 has a central zone (which is separated from the aforementioned outer peripheral circular crown by an annular step and, for example, has an increased thickness with respect to the thickness of the outer peripheral circular crown).

[0108] Preferably, this central (annular) zone acts as an attachment plate for the grinding wheel 10 to the spindle of the grinding machine (if necessary).

[0109] For this purpose, the second body 22, in said central zone, comprises a plurality of further attachment holes 225, for example through holes.

[0110] For example, the through axis of the attachment holes 225 is parallel to the central axis A.

[0111] For example, the number of attachment holes 225 is preferably equal to or higher than four.

[0112] Preferably, the attachment holes 225 are evenly distributed along the circumference of the central zone of the second body 22, preferably aligned along one or more concentric imaginary circumferences with respect to the second body 22.

[0113] In the example, the attachment holes 225 are evenly distributed along the circumference of the second body 22 and, are aligned along two concentric imaginary circumferences with respect to the second body 22.

[0114] A first series of (four) attachment holes 225 provide attachment holes 225 aligned along a first imaginary circumference centred on the central axis A and a second series of (four) attachment holes 225 provide attachment holes 225 that are aligned along a second imaginary circumference centred on the central axis A and having a diameter larger than the first imaginary circumference.

[0115] The adjacent attachment holes 225 (of each series of attachment holes 225) are spaced from each other by an angular distance equal to 90°.

[0116] The support body 20 comprises fixing members that joins (coaxially) the first body 21 and the second body 22.

[0117] The fixing members, in practice, join the second body 22 rearwardly to the first body 21, i.e. at its inner face 212 (opposite the outer face that supports the circular abrasive crown 30).

[0118] The fixing members comprise or are constituted by a plurality of bolts 40, the number of which is preferably higher than eight.

[0119] The plurality of bolts 40 are configured to clamp the first body 21 and the second body 22.

[0120] Each bolt 40 of the plurality of bolts 40 is configured to be inserted (from the side of the outer face 221 of the second body 22) into a respective hole 224 of the second body 22 and screwed into a respective (coaxial) threaded hole 214 of the first body 21.

[0121] Each bolt 40 is, in practice, concealedly connected within the thickness of the support body 20 (i.e. its head is recessed or flush with the outer face 221 of the second body 22).

[0122] In practice, the bolts 40 (which occupy-preferably all-the holes 224 and the threaded holes 214) are evenly distributed along the circumference of the first body 21 and / or of the second body 22, preferably aligned along the aforementioned imaginary circumference(s).

[0123] In practice, the adjacent bolts 40 are spaced from each other by an angular distance of less than or equal to 45°.

[0124] In more detail, the bolts 40 that occupy (to size) the first series of holes 224 and are screwed to the first series of threaded holes 214 have a mutual angular distance of 22.5°.

[0125] Furthermore, the bolts 40 that occupy (to size) the second series of holes 224 and are screwed to the second series of threaded holes 214 have a mutual angular distance of 30°.

[0126] The bolts 40 are tightened to provide a predetermined compressive tightening force / pressure between the first body 21 and the second body 22 substantially comprised between 120 Nm and 160 Nm, preferably equal to 152 Nm.

[0127] For example, each bolt 40 is tightened with a tightening torque greater than or equal to 6 Nm, for example comprised between 6 Nm and 8 Nm, preferably equal to 7.6 Nm).

[0128] Advantageously, the fixing means may—further—comprise anti-unscrewing means of the bolts 40 and / or of each bolt 40, for example configured to prevent / hinder the involuntary unscrewing thereof.

[0129] Preferably, the anti-unscrewing means comprise (or are constituted by) a thread-locker glue / adhesive (for each bolt 40), such as for example Locktite or the like.

[0130] Alternatively or in addition to the above, the fixing members may be of the glue or welding type or other fixing technique such as to allow (removable or permanent) fixing between the first body 21 and the second body 22, for example in this case the fixing members may comprise or be constituted by a layer of glue interposed between the inner face 212 of the first body 21 and the inner face 222 of the second body 22.

[0131] In a simplified embodiment of the invention illustrated in FIG. 1, the support body 20 is constituted exclusively (except for the fixing members) by the first body 21 and by the second body 22, coaxially associated so that the inner face 212 of the first body 21 is placed in (close) direct and forced contact with the inner face 222 of the second body 22.

[0132] In particular, the inner face 212 of the first body 21 is fully in contact with an annular portion of the (outer peripheral circular crown) of the inner face 222 of the second body 22.

[0133] In a further and preferred embodiment shown in FIG. 6, between the first body 21 and the second body 22, i.e. between the inner face 212 of the first body 21 and the inner face 222 of the second body 22, an intermediate (annular) body 23 is interposed coaxially fixed to the first body 21 and to the second body 22.

[0134] The intermediate body 23 is configured to further abate noise and / or vibrations of the grinding wheel 10.

[0135] In practice, the intermediate body 23 has a damper and / or attenuator function.

[0136] The intermediate body 23 is provided with a first (substantially or globally) planar face 231 and a second face 232 opposite the first face 231, which may for example also be planar and, preferably, parallel to the first face 231.

[0137] The first face 231 and the second face 232 are for example orthogonal to the central axis A of the support body 20 (i.e. of the intermediate body 23).

[0138] Preferably, the intermediate body 23 is monolithic, i.e. made in a single body.

[0139] The intermediate body 23 is for example rigid, i.e. substantially non-deformable, at least under compression, to the usual stresses to which it is subjected in operation. The intermediate body 23 is preferably made of a third metallic material, preferably different from the first material and the second material.

[0140] For example, the third metallic material of which the intermediate body 23 is made has a specific weight greater than the specific weight of the first metallic material of which the first body 21 is made.

[0141] For example, the third metallic material of which the intermediate body 23 is made is copper.

[0142] The intermediate body 23 is constituted by (or comprises) a plate-shaped body, the thickness of which is defined by the distance between the first face 231 and the second face 232, which define the main faces of the intermediate body 23, i.e. of the plate-shaped body itself.

[0143] The intermediate body 23 has a thickness less than the thickness of the first body 21 and / or of the second body 22, preferably comprised between 0.1 mm and 2 mm, more preferably equal to 0.3 mm + / −0.05 mm.

[0144] The intermediate body 233, for example, comprises a (wide) central hole and an outer (circular) perimeter edge.

[0145] The dimensions (outer diameter and inner diameter) of the intermediate body 23—except for the thickness—are similar or preferably identical to those of the first body 21.

[0146] On the intermediate body 23 there are obtained a plurality of further through holes 234 (i.e. which pass from side to side, in the direction of thickness, from the first face 231 to the second face 232).

[0147] Advantageously, the through axis of the further holes 234 is parallel to the central axis A.

[0148] For example, the number of the further holes 234 is preferably higher than eight. Preferably, the further holes 234 are evenly distributed along the circumference of the intermediate body 23, preferably aligned along one or more concentric imaginary circumferences with respect to the intermediate body 23.

[0149] In the example, the further holes 234 are evenly distributed along the circumference of the intermediate body 23 and, are aligned along two concentric imaginary circumferences with respect to the intermediate body 23.

[0150] A first series of further holes 234 provide further holes 234 aligned along a first imaginary circumference centred on the central axis A and a second series of further holes 234 provide further holes 234 that are aligned along a second imaginary circumference centred on the central axis A and having a diameter greater than the first imaginary circumference.

[0151] The further adjacent holes 234 (of each series of further holes 234) are spaced from each other by an angular distance of less than or equal to 45°.

[0152] For example, the further holes 234 of the first series of holes 234 (on the first imaginary circumference of smaller diameter) have a mutual angular distance of 22.5°.

[0153] In the example, the further holes 234 of the first series of holes 234 (on the first imaginary circumference of smaller diameter) have diameters different from each other, in particular a first group (equal to half of the further holes 234) has a diameter larger than (or double) the diameter of a second group (equal to half of the further holes 234) of holes 234 and, in addition, the holes 234 of the first group are spaced from the holes 234 of the second group.

[0154] Furthermore, the further holes 234 of the second series of holes 234 (on the second imaginary circumference of larger diameter) have a mutual angular distance of 30°. In the example, the further holes 234 of the second series of holes 234 (on the second imaginary circumference of larger diameter) have diameters equal to each other.

[0155] It is not excluded that the further holes 234 have a different conformation / arrangement with respect to the one described and illustrated above.

[0156] In this preferred embodiment, the intermediate layer 23 is (forcibly) clamped between the first body 21 and the second body 22.

[0157] For example, the support body 20 is constituted exclusively (except for the fixing members) by the first body 21, the (only) intermediate body 23 and the second body 22, coaxially associated so that:

[0158] the inner face 212 of the first body 21 is placed in (close) direct and forced contact with one between the first face 231 and the second face 232 of the intermediate body 23 (in the example to the first face 231) and

[0159] the inner face 222 of the second body 22 is placed in (close) direct and forced contact to the other between the second face 232 and the first face 231 of the intermediate body 23 (in the example to the second face 232).

[0160] In particular, the entire inner face 212 of the first body 21 is fully in contact with the (entire) first face 231 of the intermediate body 23 and an annular portion of the (outer peripheral circular crown) of the inner face 222 of the second body 22 is fully in contact with the (entire) second face 232 of the intermediate body 23.

[0161] Also in this case, the fixing members comprise or are constituted by a plurality of bolts 40, the number of which is preferably higher than eight.

[0162] The plurality of bolts 40 is configured to clamp the first body 21 and the second body 22, with the intermediate body 23 interposed therebetween.

[0163] Each bolt 40 of the plurality of bolts 40 is configured to be inserted (from the side of the outer face 221 of the second body 22) into a respective hole 224 of the second body 22, into a corresponding further coaxial hole 234 of the intermediate body 23 and screwed into a respective (coaxial) threaded hole 214 of the first body 21.

[0164] Each bolt 40 is, in practice, concealedly connected within the thickness of the support body 20 (i.e. its head is recessed or flush with the outer face 221 of the second body 22).

[0165] In practice, the bolts 40 (which occupy-preferably all-the holes 224, the further holes 234 and the threaded holes 214) are evenly distributed along the circumference of the first body 21 and / or of the second body 22 and / or of the intermediate body 23, preferably aligned along the aforesaid imaginary circumference(s) (with the aforesaid angular distances and spatial arrangements).

[0166] The bolts 40 are tightened to provide a predetermined compressive tightening force / pressure between the first body 21 and the second body 22 and the intermediate body 23 substantially comprised between 120 Nm and 160 Nm, preferably equal to 152 Nm.

[0167] For example, each bolt 40 is tightened with a tightening torque greater than or equal to 6 Nm, for example comprised between 6 Nm and 8 Nm, preferably equal to 7.6 Nm).

[0168] Also in this case, the fixing means may further comprise anti-unscrewing means of the bolts 40 and / or of each bolt 40, for example configured to prevent / hinder the involuntary unscrewing thereof.

[0169] Preferably, the anti-unscrewing means comprise (or are constituted by) a thread-locker glue / adhesive (for each bolt 40), such as for example Locktite or the like.

[0170] Alternatively or in addition to the above, the fixing members may be of the glue or welding type or other fixing technique such as to allow (removable or permanent) fixing between the first body 21, the intermediate body 23 and the second body 22, for example in this case the fixing members may comprise or be constituted by a first layer of glue interposed between the inner face 212 of the first body 21 and the first face 231 of the intermediate body 23 and a second layer of glue interposed between the inner face 222 of the second body 22 and the second face 232 of the intermediate body 23.

[0171] The support body 20, thus formed, is adapted to be installed coaxially-by means of appropriate tightening bolts-to the rotating spindle of a grinding machine or other machine suitable for processing ceramic tiles or the like, for the execution of the squaring or grinding processing thereof and / or other suitable processing.

[0172] It is also not excluded that the support body 20 can be formed by joining more than two (or three) annular bodies, wherein the sandwich-like structure described above is formed by more layers than those of the structures described above.

[0173] A preferred use of such a grinding wheel 10 is the use in a process for dry grinding / squaring ceramic tiles (i.e. a process that does not involve the use of cooling media or liquid lubricants or water) and is suitable for removing ceramic material from the edges or from the surfaces of ceramic tiles during the grinding / squaring process.

[0174] The aforementioned grinding wheel 10 is made by means of a manufacturing method comprising the steps of:

[0175] forming, for example by casting and / or mechanical machining, the first annular or discoidal body 21;

[0176] forming, by pressing and / or other suitable forming technique, a diamond abrasive material on the peripheral support surface 213 of the first body 21;

[0177] forming, for example by casting and / or mechanical machining, the second annular or discoidal body 22;

[0178] optionally forming, by cutting a sheet, an intermediate body 23 and interposing the intermediate body 23, between the first body 21 and the second body 23; and

[0179] tightening the first body 21 and the second body 22 together, preferably using the aforementioned plurality of bolts 40 (and applying the aforementioned tightening force).

[0180] It has been observed that, when the grinding wheel 10—thus made—is in use (and the circular abrasive crown 30 rubs against the ceramic tiles or other material to be worked), thanks to the structural discontinuity between the first body 21 and the second body 22—and / or, even more, thanks to the presence of the intermediate body 23 that accentuates this discontinuity mechanically and / or physically—, the sound emitted by this grinding wheel 10 is decidedly more attenuated (in terms of sound intensity and / or in terms of frequency of sound emission / vibration), compared to traditional grinding wheels in which the support bodies are monolithic, allowing a reduction in the sound emission and discomfort of the grinding wheel itself.

[0181] In particular, a reduction of the sound intensity by 3-10 dB (for example by 5-7 dB) was observed, for each grinding wheel 10 and / or in the total number of grinding wheels 10 used in a grinding machine.

[0182] In addition, for example, a (considerable) attenuation of the emission frequency was observed (which switches from a sharp sound—“Grima”—to a deep sound). The invention thus conceived is susceptible to many modifications and variants, all falling within the same inventive concept.

[0183] Moreover, all details can be replaced by other technically equivalent elements.

[0184] In practice, the materials used, as well as the contingent shapes and sizes, can be whatever according to the requirements without for this reason departing from the scope of protection of the following claims.

Examples

Embodiment Construction

[0056]With particular reference to these figures, globally indicated with 10 is a dry diamond abrasive grinding wheel, i.e. for dry processing, in particular for dry grinding ceramic tiles (or other similar material, such as natural stone slabs, glass or the like).

[0057]The grinding wheel 10 comprises an annular or discoidal support body 20, provided with a central axis A, which is configured to be fixed (coaxially and removably) to a rotating spindle of a grinding machine (not illustrated as of known type).

[0058]The support body 20 may overall have a stratiform or “sandwich”-like structure.

[0059]The support body 20, in particular, comprises a first body 21 provided with a (substantially or globally) planar outer face 211 and an inner face 212 opposite the outer face 211, which may for example also be planar and, preferably, parallel to the outer face 211.

[0060]The outer face 211 and the inner face 212 are for example orthogonal to the central axis A of the support body 20 (i.e. of ...

Claims

1. A dry diamond grinding wheel for dry grinding ceramic tiles comprising:an annular or discoidal support body configured to be fixed to a rotating spindle of a grinding machine;wherein the support body comprises a peripheral support surface supporting a diamond abrasive material, a first annular body having an outer face that comprises the peripheral support surface supporting the diamond abrasive material and a second annular or discoidal body fixed coaxially to the first body at an inner face of the first body opposite the outer face.

2. The grinding wheel according to claim 1, wherein the first body is made of a first metallic material, preferably steel or iron.

3. The grinding wheel according to claim 2, wherein the second body is made of a second metallic material different from the first metallic material, preferably having a specific weight lower than the specific weight of the first metallic material, for example aluminium.

4. The grinding wheel according to claim 1, wherein an intermediate body coaxially fixed to the first body and the second body and configured to abate noise and / or vibrations is interposed between the first body and the second body.

5. The grinding wheel according to claim 4, wherein the intermediate body is made of a third metallic material different from the first material and the second material, preferably copper.

6. The grinding wheel according to claim 4, wherein the intermediate body is made of a third metallic material having a specific weight greater than the specific weight of the first material.

7. The grinding wheel according to claim 4, wherein the intermediate body has a thickness less than the thickness of the first body and / or of the second body, preferably comprised between 0.1 mm and 2 mm.

8. The grinding wheel according to claim 1, wherein the support body is constituted by and by the second body, wherein the inner face of the first body is placed into direct forced contact with an inner face of the second body.

9. The grinding wheel according to claim 1, wherein the first body and the second body are firmly fixed together by means of a plurality of bolts, the number of which is preferably higher than eight.

10. The grinding wheel according to claim 9, wherein the bolts are evenly distributed along the circumference of the first body and / or of the second body, preferably aligned along one or more concentric imaginary circumferences with respect to the first body and / or the second body.

11. The grinding wheel according to claim 9, wherein adjacent bolts are spaced from each other by an angular distance of less than or equal to 45°.

12. The grinding wheel according to claim 9, wherein each bolt is tightened with a tightening torque greater than or equal to 6 Nm, preferably comprised between 6 Nm and 8 Nm.

13. The grinding wheel according to claim 1, wherein at least one between the first body and the second body comprises fixing holes, preferably aligned along a further concentric imaginary circumference with respect to the first body and / or the second body, for fixing the grinding wheel to the rotating spindle of the grinding machine.

14. The grinding wheel according to claim 1, wherein the diamond abrasive material is formed by a compound comprising a matrix to which the abrasive diamond is added, wherein preferably the diamond abrasive material comprises a percent-age of diamond greater than or equal to 20%, preferably greater than or equal to 25%, by weight with respect to the total weight of the matrix forming the com-pound of diamond abrasive material.

15. A process for dry grinding ceramic tiles, the improvement comprising using the dry diamond grinding wheel according to claim 1 configured to operate without the use of a liquid cooling or lubricating medium and is adapted to remove ceramic material from the edges or surfaces of the ceramic tiles during the grinding process.

16. A method for manufacturing a dry diamond grinding wheel for grinding ceramic tiles, comprising the steps of:forming a first annular or discoidal body of a support body in a first metallic material, the first body comprising a peripheral support surface for a diamond abrasive material;forming a diamond abrasive material on the peripheral support surface of the first body;forming a second annular or discoidal body of the support body in a second metallic material, preferably different from the first metallic material;optionally interposing an intermediate body, preferably made of a third metallic material different from the first material and the second material, between the first body and the second body; andtightening the first body and the second body together, preferably using a plurality of bolts, more preferably in a number greater than 8 and / or arranged circumferentially with an angular distance less than or equal to 45°.

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