FIELD OF THE INVENTION

The embodiments described here concern a finishing tool for surface machining slab-like elements. In particular, the finishing tool is provided with an abrasive surface to perform smoothing, lapping and surface finish machining of slab-like elements, for example made of stone material, marble, granite, or ceramic, gres porcelain stoneware or suchlike, or similar materials.

BACKGROUND OF THE INVENTION

In the ceramic sector that produces slabs, sheets, tiles and slab-like elements in general used to cover walls and floors, it is known that the slab-like elements can undergo different surface mechanical machining, for example smoothing and lapping, in order to obtain the surface properties required.

The slab-like elements, for example in the case of gres porcelain and technical stoneware, are typically manufactured with a ceramic support body which is possibly covered with an engobe layer where a decoration can be applied, which is then covered with an enamel or crystalline surface layer.

The slab-like element thus obtained has to be smoothed or lapped in order to reduce roughness, surface ridges, or improve flatness and create a surface with desired roughness and/or flatness.

Currently, such machining is performed with apparatuses or machinery provided with consumable finishing tools which, by rotating at high speed, act on the surface, removing a layer of a certain thickness from it. A certain number of finishing tools are usually mounted on respective abrasive sectors of a support member, for example angular sectors equally angularly distanced along its peripheral edge. A typical configuration provides at least six or eight finishing tools associated with the same support member.

Each finishing tool is made enbloc, with a consumable abrasive material, and it comprises a base, known as support or “holder” in the sector, to which an abrasive component is firmly glued, which is provided with a plurality of projecting abrasive elements configured to exert the abrading action on the slab-like element. The base is in turn formed by a support of thermoplastic material, configured to guarantee a stable connection between the tool and the support member, and an intermediate elastic layer, made of vulcanized rubber and configured to give elasticity to the finishing tool. This intermediate elastic layer is necessary to guarantee the finishing tool has a certain elasticity, which gives it the possibility of having minimal movements, for example in reaction to the force that is generated when it exerts the abrading action, without such movements causing the detachment of the finishing tool from the support member.

It is known that, after a machining cycle, the abrasion surface can be worn out and therefore unusable. Since the tools in question are made enbloc, once the abrasion surface is worn out it is necessary to completely replace the tool, with disposal thereof. Obviously, such a “disposable” approach is inherently expensive.

Furthermore, the base of the tool, which is formed by the support of thermoplastic material and by the intermediate elastic layer of polymeric material subjected to a cross-linking process (such as vulcanized rubber, for example), needs to be disposed of as special waste, since these components, made of different materials, are bound together in a definitive way. This aspect implies that the costs associated with this known solution and its disposal are increased further, on top of which there is the serious environmental impact that derives from it.

In order to attempt to overcome some of these disadvantages, some solutions have been developed in which the consumable abrasive material of the finishing tool is releasably connected to the base, in such a way that it can be separated from the base once it reaches the end of its useful life, and be replaced with new consumable abrasive material.

These known solutions therefore provide various types of releasable connection means. For example, EP-A1-2.484.487 and WO-A1-2008/035383 describe a dovetail mechanical connection between the base and the consumable abrasive material, while US-A1-2011/287800 describes another type of mechanical connection, consisting of a plurality of teeth which project from the base and engage in as many holes provided on the portion of consumable abrasive material. US-A 1-2010/267319 describes the use of layers of tear-off material, in particular of the slot-hook type, such as Velcro® for example. KR-U-2009/0012814 describes the use of magnets, which engage with elements made of suitable ferromagnetic material, to removably connect the consumable abrasive material to the base. There is therefore the need to perfect a finishing tool that can overcome at least one of the disadvantages of the state of the art.

In particular, one purpose of the present invention is to make available a finishing tool which, once the abrasion surface has worn out, does not involve high disposal and replacement costs, and guarantees an easy and rapid replacement of the abrasive surface with new abrasive material.

Another purpose of the present invention is to make available a finishing tool that has at least one portion that, at the end of its life, can be sent for selective disposal so as to make the tool at least partly recyclable.

Another purpose of the present invention is to provide a finishing tool that has the components firmly anchored to each other while it is used, albeit in the presence of temporary connections that allow to separate such components at the end of their respective useful lives.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claim, while the dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

Some embodiments concern a finishing tool for surface machining slab-like elements. In one embodiment, the tool comprises a reusable base and an abrasive component releasably connected to the base in order to be selectively replaced.

Advantageously, therefore, when the abrasive component is worn out, it can be replaced with another abrasive component, reusing the base instead.

Some embodiments concern a finishing tool in which, when the base is worn out, the support of thermoplastic material can be separated from the elastic member of polymeric material subject to cross-linking, in order to be able to send the thermoplastic support and the elastic member to selective disposal so as to make the tool at least partly recyclable and reduce its environmental impact.

Some embodiments of the present invention provide to make available a finishing tool in which releasable connection means are provided between the base and the abrasive component. Some embodiments of the present invention provide to make available a finishing tool in which releasable connection means are also provided between the thermoplastic support and the elastic member.

DESCRIPTION OF THE DRAWINGS

These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a three-dimensional view of a finishing tool according to some embodiments described here;

- fig. 2 is a partly sectioned three-dimensional view of the finishing tool of fig. 1 ;

- figs. 3 and 4 are schematic representations of an enlargement of part of a finishing tool according to two alternative embodiments described here;

- fig. 5 is a schematic and exploded three-dimensional view of the finishing tool of figs. 1 and 2;

- fig. 6 is a schematic and exploded three-dimensional view of a variant of the finishing tool of fig. 1 ;

- fig. 7 is a schematic front view of the finishing tool of fig. 1 shown in an operating condition, in association with a slab-like element;

- fig. 7a is an enlarged view of fig. 7;

- fig. 8 is a schematic and exploded lateral view of the finishing tool of fig. 1 ;

- fig. 9 is a schematic and exploded three-dimensional view of a variant of the finishing tool of fig. 1 ;

- figs. 10 and 11 are schematic and exploded three-dimensional views of other embodiments of a finishing tool produced according to the teachings of the present invention;

- figs. 12 and 13 are schematic representations of two different methods for separating the components of the finishing tools according to the embodiments of figs. 10 and 11.

We must clarify that in the present description the phraseology and terminology used, as well as the figures in the attached drawings also as described, have the sole function of better illustrating and explaining the present invention, their function being to provide a non-limiting example of the invention itself, since the scope of protection is defined by the claims. To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications.

DESCRIPTION OF SOME EMBODIMENTS

The attached drawings are used to describe some embodiments of a finishing tool 10, which can be used for surface machining slab-like elements. In particular, the finishing tool 10 is provided with an abrasive surface to perform smoothing, lapping and surface finish machining of slab-like elements, for example made of stone material, marble, granite, or ceramic, gres porcelain stoneware or suchlike, or similar materials. A slab-like element 11 is shown schematically in fig. 7, for example in operative association with a tool 10 according to the present description.

The tool 10 comprises a base, or support, 12 and an abrasive component 14. The abrasive component 14 is releasably connected to the base 12. In this way, even if after a machining cycle the abrasive surface of the abrasive component 14 is worn out and therefore unusable, with the present invention it is not necessary to completely eliminate the entire tool 10, but only to remove the worn out and exhausted abrasive component 14 while preserving the base 12 instead, which can be favorably reused for other machining cycles, since on each occasion it is suitably connected to a new abrasive component 14. The latter, therefore, represents the “disposable” element of the tool 10, while the base 12, since it can be separated from the abrasive component 14, can be reused a certain number of times. This solution, therefore, considerably reduces costs, since it is possible to recover and reuse the base 12 for many machining cycles. Furthermore, this solution also has an impact on disposal costs, which are reduced because the base 12 can, as mentioned, be reused several times.

The base 12 can be configured as a traditional support (“holder”) for known types of machining machines, for example with liquid cooling, and therefore include a support 32, for example made of ABS or other suitable polymeric resin and configured to be temporarily and firmly attached to the machining machine to which the finishing tool is able to be connected, and an elastic member 34, made of polymeric material subjected to a cross-linking process, for example of vulcanized rubber, and configured to allow a certain degree of freedom of movement of the abrasive component 14, when it is subjected to the stresses generated during the abrasive action, with respect to the base 12.

In some embodiments, the tool 10 described here comprises releasable attachment means 16 configured to releasably attach the abrasive component 14 to the base 12; in this way, thanks to the presence of the releasable attachment means 16, it is possible to selectively couple and uncouple the abrasive component 14 to/from the base 12.

The releasable attachment means 16 are, in particular, configured to determine a releasable reciprocal coupling between the abrasive component 14 and the base 12, which is effective both in a direction essentially orthogonal to a main interface plane A of the abrasive component 14 and of the base 12 (arrow T), and also in a direction tangential to the main interface plane A, that is, shear stress, as indicated by the arrow S (see for example figs. 1 , 4 and 7). The coupling and hold in the direction of the arrow T is important because it determines the primary association between the abrasive component 14 and the base 12, while the coupling and hold in the direction of the arrow S is equally important because it comes into play to contrast the shear stresses to which the abrasive component 14 is subjected when the tool 10 interacts with the surface of the slab-like element 11 for finishing purposes.

In some embodiments, the releasable attachment means 16 comprise base attachment means 18 present on, or associated with, the base 12 and component attachment counter-means 20 present on, or associated with, the abrasive component 14. The base attachment means 18 and the component attachment counter-means 20 are configured to determine a releasable reciprocal coupling, as described above.

In some embodiments, the releasable attachment means 16 comprise attachment means of the mechanical type, as in the embodiment of figs, from 1 to 9, while in other embodiments the releasable attachment means 16 comprise attachment means of the chemical type, as in the embodiments of figs. 10 and 11.

In particular, in the embodiment in which the releasable attachment means 16 comprise attachment means of the mechanical type (figs. 1-7), the base attachment means 18 can comprise a base mechanical gripping substrate 22 and the component attachment counter-means 20 comprise a component mechanical gripping substrate 24 (figs. 7, 7a and 8). Such base mechanical gripping substrate 22 and component mechanical gripping substrate 24 are reciprocally configured to determine a coordinated attachment for the purposes of the releasable coupling between the base 12 and the abrasive component 14, thus determining the coupling and hold both in the direction T as well as in the direction S described above.

In possible implementations, such base mechanical gripping substrate 22 and component mechanical gripping substrate 24 are both firmly and stably glued to the base 12 and to the abrasive component 14, respectively.

In other possible implementations, the base mechanical gripping substrate 22 can be made in one piece, that is, in a single body or enbloc, with the base 12, and therefore it can also be of the same material, while the component mechanical gripping substrate 24 is applied, preferably glued, to the abrasive component 14 and it is of a different material, favorably less valuable, compared to the material that the abrasive component 14 is made of.

In possible embodiments, such base mechanical gripping substrate 22 and component mechanical gripping substrate 24 each comprise a base layer with a planar conformation, glued to the base 12 and to the abrasive component 14, respectively, and a plurality of gripping elements 26 projecting from the base layer and essentially the same each other, both in the context of the single substrate and also between the base mechanical gripping substrate 22 and the component mechanical gripping substrate 24. The gripping elements 26 therefore define a regular alternation of solids and voids between them, for the coupling of similar gripping elements 26. The gripping elements 26 can have a filiform microstructure resembling a hook or a slot, please refer to the enlarged details shown in figs. 3 and 4, or, in general, a geometry configured to determine a firm reciprocal coupling, in particular resistant to the shear stresses that would have the tendency to detach the abrasive component 14 from the base 12 during normal use, between the base mechanical gripping substrate 22 and the component mechanical gripping substrate 24. In this way, in addition to the hold in the direction T, there is also achieved an effective coupling in the direction S, therefore resistant to tangential or shear stresses.

According to the possible implementation of fig. 3, the projecting gripping elements 26 of the base mechanical gripping substrate 22 and the component mechanical gripping substrate 24 are configured to determine a reciprocal malefemale coupling. In the example shown, the projecting gripping elements 26 of the base mechanical gripping substrate 22 are shaped as slots, or in general elements closed in a ring, and the projecting gripping elements 26 of the component mechanical gripping substrate 24 are shaped as hooks.

According to the possible implementation of fig. 4, the projecting gripping elements 26 of the base mechanical gripping substrate 22 and of the component mechanical gripping substrate 24 are configured to determine a reciprocal malemale coupling.

According to an advantageous implementation, which provides the plurality of gripping elements 26, the base mechanical gripping substrate 22 and the component mechanical gripping substrate 24 can each consist of one or more layers of identical Velcro®, glued to the base 12 and to the abrasive component 14, respectively, thus determining a Velcro® male-male coupling with interference which is reliable and safe even in the case of shear stresses to which the tool 10, and in particular the abrasive component 14, is subjected during the finishing machining.

For example, while figs. 2 and 5 show the case in which the base mechanical gripping substrate 22 and the component mechanical gripping substrate 24 respectively consist of several layers of Velcro® disposed adjacent. In this case, the layers of Velcro® can be disposed, for example, in transverse strips or in longitudinal strips.

In some embodiments described using the attached drawings, the abrasive component 14 comprises a base membrane 36 from which a plurality of abrasive elements or heads 38 project.

The base membrane 36 and the abrasive heads 38 are made, in a single body, with an abrasive composite material which is valuable, in that it is defined by a polymeric matrix with dispersed abrasive fillers. This composite material is hard and has self-healing (self-reviving) characteristics, that is, during its use the consumption of a more external layer brings to light the abrasive fillers of the lower layer.

The lower surface of the base membrane 36 has, or is associated with, the component attachment counter-means 20.

The disposition of the base attachment means 18 and of the component attachment counter-means 20 has been specifically developed by the Applicant in order to keep the abrasive heads 38 as autonomous/independent as possible during use; this aspect is reflected in the homogeneity of the surface finish of the slab-like element.

The abrasive component 14 can have a rectangular shape and the abrasive heads 38 can be disposed in parallel rows, orthogonal to the longer side. For example, the abrasive component 14 can have a preferential development along an axis X, which in fact corresponds to the axis of development of the tool 10. Alternatively, the abrasive component 14 can instead have the shape of a parallelogram. In the case of an abrasive component 14 with a preferential development along an axis X, it follows that the direction S is transverse, in particular orthogonal, to such axis X, lying essentially on the same plane, while the direction T is transverse, in particular orthogonal, to such axis X, lying however on a plane transverse to the plane on which the axis X lies. In essence, the axis X and the directions S and T form a set of three axes, or directions, oriented in space.

The space between one row of abrasive heads 38 and the next, or the previous one, defines a passage channel 40 through which, during use, the abraded material and the material released by the abrasive heads 38 are conveyed toward the outside of the abrasive component 14.

The abrasive heads 38 can have a rectangular, parallelogram, circular, elliptical or other cross section.

The abrasive heads 38 of a same abrasive component 14 can be all the same or they can also be different from each other.

The variant of fig. 6 shows the case in which the base mechanical gripping substrate 22 and the component mechanical gripping substrate 24 respectively consist of a single layer of Velcro® which extends over the entire main interface plane A.

The variant of fig. 9 is similar to that described with reference to fig. 6, with the difference that in this case the support 32 can be separated from the elastic member 34. In this way, at the end of their respective useful life, they can be correctly disposed of in a selective way, with a decrease in the environmental impact of the finishing tool 10. Furthermore, since their useful life is not necessarily the same, this offers the advantage that a new elastic member 34 can be associated with a support 32 that has already been used and is still usable, because the previous elastic member 34 has reached the end of its useful life, or vice versa.

This variant makes the finishing tool 10 very versatile because it is possible to replace each of its components at the end of their useful life, while continuing to use the remaining components that are still suitable.

In this variant, additional releasable attachment means 28 are provided, similar to the releasable attachment means 16 described above.

The additional releasable attachment means 28 comprise support attachment means 29 present on, or associated with, the support 32, and elastic member attachment counter-means 30 present on, or associated with, the elastic member 34. The support attachment means 29 and the elastic member attachment countermeans 30 are configured to determine a releasable reciprocal coupling between the support 32 and the elastic member 34, as described above.

The support attachment means 29 can comprise a support mechanical gripping substrate 42, and the support member attachment counter-means 30 comprise an elastic member mechanical gripping substrate 44. Such support mechanical gripping substrate 42 and elastic member mechanical gripping substrate 44 are firmly and stably glued to the support 32 and to the elastic member 34, respectively.

The support mechanical gripping substrate 42 and the elastic member mechanical gripping substrate 44 each comprise a base layer with a planar conformation and a plurality of gripping elements, completely similar to the gripping elements 26 previously described.

During use, when the support attachment means 29 and the elastic member attachment counter-means 30 are temporarily joined in order to releasably connect the support 32 and the elastic member 34, the support mechanical gripping substrate 42 and the elastic member mechanical gripping substrate 44 substantially lie on a secondary interface plane B, disposed parallel to the main interface plane A.

In other possible embodiments, described with reference to figs. 10 and 11, the releasable attachment means 16 are of a chemical nature and comprise, by way of a non-limiting example, at least one layer of cyanoacrylate glue, indicated with the reference number 50.

In the embodiment of fig. 10, an adhesive layer 50 is provided interposed between the base 12 and the abrasive component 14. In the process of manufacturing the finishing tool 10, the adhesive layer 50 is applied on the base 12, in particular on the face of the elastic member 34 that faces, during use, toward the abrasive component 14.

In some embodiments, the adhesive layer 50 is formed by cyanoacrylate glue, possibly with the addition of particles of electrically conductive materials, such as iron or graphite particles, for example.

The layer 50 between the base 12 and the abrasive component 14 is also provided in the embodiment of fig. 11. In addition, an additional adhesive layer 50’ is provided, interposed between the support 32 and the elastic member 34. In the process of manufacturing the finishing tool 10 according to this embodiment, the additional layer 50’ is applied on the support 32, in particular on its face that faces, during use, toward the elastic member 34.

In some embodiments, the additional adhesive layer 50’ is formed by cyanoacrylate glue, possibly with the addition of particles of electrically conductive materials, such as particles of iron or graphite, for example.

The embodiment of fig. 11 , similarly to that of fig. 9, has a releasable reciprocal coupling between the support 32 and the elastic member 34, and therefore allows to achieve the same advantages described previously with reference to fig. 9, which are not repeated here for the sake of brevity.

Some possible modes of separating the various components of the finishing tool 10 are described below.

If the releasable attachment means 16 are of a mechanical nature, as in the embodiments of figs. 1-9, it is quite clear to the person of skill in the art that it is sufficient to exert a force such as to disengage the attachment means from the attachment counter-means to separate one or more components of the finishing tool 10 from the other components.

If the releasable attachment means 16 are of a chemical nature, as in the embodiments of figs. 10 and 11, the finishing tool 10 has to be heated in order to determine the thermal degradation of the layer 50, 50’. Some embodiments described here provide to carry out a heating method that uses electromagnetic radiation.

When the softening temperature characteristic of the layer 50, 50’ of cyanoacrylate glue is reached, which typically can be around 70°C, the cyanoacrylate glue loses its adhesive properties, and it is possible to separate the components.

With reference to figs. 12 and 13, hereafter we describe, by way of a nonlimiting example, two possible heating methods to achieve the degradation of the layer 50, 50’ of cyanoacrylate glue.

We must clarify that although the drawings show finishing tools 10 that comprise both the layer 50 of cyanoacrylate glue between the abrasive component 14 and the base 12, and also the additional layer 50’ of cyanoacrylate glue between the support 32 and the elastic member 34, it is entirely clear that the same method is also applied to finishing tools 10 that only comprise the layer 50 of cyanoacrylate glue between the abrasive component 14 and the base 12.

With reference to fig. 12, a heating method is described in which the electromagnetic radiation is microwave radiation. The finishing tools 10, which advance on a machining line 100, pass through a furnace 101 inside which microwave emission means 102 are disposed. The latter carry out a uniform heating of the layers 50, 50’, in particular in localized zones 103 indicated by a dashed ellipse in fig. 12. This determines the electromagnetic excitation of the ionic bonds of the cyanoacrylate glue, and a consequent dissipation of the thermal energy by friction, such as to bring the glue to its softening temperature.

With reference to fig. 13, on the other hand, an induction heating method is described, which is particularly suitable for embodiments in which electrically conductive particles have been added to the layers 50, 50’ of cyanoacrylate glue. The finishing tools 10, which advance on a machining line 100, pass through an induction furnace 101 inside which one or more induction members 104 are disposed. The action of the latter determines the heating by induction of the electrically conductive particles present in the layers 50, 50’ of cyanoacrylate glue, which cause an increase in the uniform temperature of such layers until the softening temperature of the cyanoacrylate glue is reached.

In both examples described above, upon exiting the furnace 101 the abrasive component 14 has been separated from the base 12, in which the support 32 and the elastic member 34 have in turn been separated from each other (condition shown on the right in figs. 12 and 13).

We must clarify that the heating method allows to degrade the layer 50, 50’ but it does not damage the base 12 in any way whatsoever. In fact, both the support 32 and also the elastic member 34 are made with materials that have softening temperatures higher than those of the cyanoacrylate glue. For example, the rubber and the thermoplastic materials that the support 32 and the elastic member 34 are typically made of have softening temperatures of approximately 250°C and 95°C, respectively, and therefore the heating method does not compromise the structural characteristics of the reusable parts of the finishing tool 10.

It is clear that modifications and/or additions of parts may be made to the finishing tool 10 as described heretofore, without departing from the field and scope of the present invention, as defined by the claims.

It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of finishing tool, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

In the following claims, the sole purpose of the references in brackets is to facilitate their reading and they must not be considered as restrictive factors with regard to the field of protection defined by the same claims.