ABRASIVE TOOL DESCRIPTION

The present invention relates to a supporting device for an abrasive tool and to a corresponding abrasive tool of improved type.

As is known, abrasive surface machining, such as lapping, polishing or grinding of stone material, marble, ceramic, glass material and the like, requires the use of abrasive tools, which are brought into pressurized contact with the surface to be processed. These abrasive tools are normally supported by a head for abrasive tools, which is a machine capable of forcing relative movements between the material to be machined and the abrasive tools and to produce the necessary pressure of said abrasive tools on said surface to be machined, so as to allow surface machining to be implemented.

Currently, to grind, polish and/or lap above all ceramic tiles after production a disposable tool is used, which is generally composed of a rigid interface element (normally made of thermoplastic material) to house the tool in the grinding machine. This rigid interface element is joined, normally by gluing, to a spacer and shock absorber element made of elastomeric material on which the actual abrasive component is positioned, again by gluing.

Therefore, in substance, current abrasive tools normally consist of an actual abrasive layer and of a supporting device comprising the rigid interface element and the spacer element made of elastomeric material described above.

Supporting devices comprising the two elements, the element made of thermoplastic material and the element made of elastomer, are normally manufactured by third party companies which then sell them, either separately or assembled, to the manufacturers of abrasives that produce the actual abrasive tool.

The machines that use said abrasive tools are usually called tangential grinders and are schematically composed of a conveyor belt on which the tiles and/or stones to be ground are positioned and of a variable number of grinding heads, for example up to 36 grinding heads. Said grinding heads, positioned over the conveyor belt, are composed of arms (up to 8 per head) that rotate, typically at up to around 600 rpm. Besides rotating, each arm also has a swinging movement that carries the tool into contact with the surface to be ground according to a tangent line - giving the machine its name - for the whole of the length of the abrasive. Finally, a jet of water (or other liquid suitable for the purpose) can be delivered from each head to lubricate, wash away the sludge and cool the grinding system.

Currently, there are increasing requests by the market for the use of a softer elastomeric material with respect to the 36/40 SH normally used currently to produce the shock absorbing spacer, so that the abrasive can follow the surface to be ground or polished more smoothly. The simplest solutions currently in use are an increase in the thickness of the layer made of elastomeric material or the use of a softer elastomer.

In the first case, besides substantially increasing costs, both due to the larger amount of raw material and to the longer production cycle, there is also a worsening of the problem of delay in the elastic response at the moment in which the abrasive touches the surface to be machined.

In practice, the abrasive - due to a longer lever arm resulting from the increased thickness of the spacer element made of elastomeric material - is more likely to stop upon contact with the surface to be machined, as the thicker layer of elastomeric material absorbs more energy in that instant, subsequently releasing it with a "whiplash" effect. This causes a very discontinuous movement of the abrasive part, creating micro-irregularities on the surfaces that greatly penalize the quality of polishing.

In the case of use of a softer elastomer, in addition to the aforesaid negative effects, an even greater problem is encountered, as a softer elastomer is unable to withstand the high shear stress generated by contact between the abrasive and the element to be ground, and therefore becomes extremely deformed or even lacerated. It is clear that this possibility is catastrophic for the assembly, as the abrasive element, normally consisting of a diamond grinding wheel, is lost.

A further problem to be solved with respect to the current state of the art is the fact that - due to how ceramic grinding machines are constructed - the abrasive operates in the various contact points at a very different speed. The difference in speed due to the different radius of rotation of the head of the machine can even reach, in the maximum point, 200% of the speed value of the minimum point. This condition would require, for balanced operation, an elastic response that differs as a function of the position, which it practically impossible with spacer elements made of elastomeric material produced with the current geometries.

A further request by the market is that of performing "dry" machining, i.e., without the use of water or other liquids to wash away the sludges and cool the abrasives. This solution clearly firstly requires the use of resins and/or different materials for the abrasives, but also requires a supporting and shock absorbing part that has markedly different characteristics to those currently in use.

Manufacturers are also studying modifications to machinery that can improve the yield and the quality of the end product, given that the simple replacement of water with air as coolant and cleaning element is not giving the desired results.

It would therefore be desirable to provide a supporting device for an abrasive tool that allows the aforesaid problems to be solved.

Therefore, an object of the present invention is to provide a supporting device for an abrasive tool that allows the use of a softer elastomer interposed between the rigid interface element and the abrasive tool.

A further object of the present invention is to provide a supporting device for an abrasive tool that does not require excessive thicknesses of the elastomeric layer interposed between the rigid interface element and the abrasive tool.

Another object of the present invention is to provide a supporting device for an abrasive tool that is able to provide a different elastic response as a function of position.

Yet another object of the present invention is to provide a supporting device for an abrasive tool that enables abrasive surface machining operations, such as lapping, polishing or grinding of stone material, marble, ceramic, glass material and the like, to be carried out without the use of water or other liquids to wash away the sludges and cool the abrasives.

One more object of the present invention is to provide a supporting device for an abrasive tool that is easy to manufacture at competitive costs.

This need is satisfied with the solution proposed by the present utility model, which relates to a supporting device for an abrasive tool of improved type.

Therefore, the subject matter of the present utility model is a supporting device for supporting and containing an abrasive element for machining stone materials, ceramics or the like, comprising a first rigid interface element with a grinding machine and a second shock absorbing element made of elastomeric material for coupling with an abrasive tool. The supporting device of the present invention is characterized in that said first rigid element comprises a first shaped body having a first coupling surface provided with first coupling means and said second shock absorbing element comprises a second shaped body having a second coupling surface provided with second coupling means, said first and second coupling means being at least partially mutually couplable in operation so as to impart a predetermined elastic response to the operating stresses imposed on said supporting device.

In this way, a supporting device for supporting and containing an abrasive element for machining stone materials, ceramics or the like, which fully satisfies the aforesaid objects, is obtained.

In particular, the solution proposed is based on the principle of varying the geometry of the elastomeric component and/or of the rigid element of the support so as to vary the elastic response according to need, without however introducing undesirable effects such as those described previously, but on the contrary reducing these undesirable effects with respect to the current art and simultaneously also reducing manufacturing costs.

Said solution makes it possible to achieve an elastic response diversified according to the requests, practically in each point of the system with appropriate variations of the geometries, with a variability of response that is absolutely impossible to achieve with the prior art system.

Advantageously, said first shaped body is made of thermoplastic material and said second shaped body is made of elastomeric material.

Preferably, said first coupling means comprise one or more protrusions and said second coupling means comprise one or more recesses.

Alternatively, said first coupling means comprise one or more recesses and said second coupling means comprise one or more protrusions.

In a first embodiment of a supporting device for supporting and containing an abrasive element according to the present invention, said one or more protrusions completely penetrate corresponding one or more recesses.

In a second embodiment of a supporting device for supporting and containing an abrasive element according to the present invention, said one or more protrusions penetrate corresponding one or more recesses with an interference that generates a preload during assembly resting even partially only along an axis or even only one direction of said axis. In a third embodiment of a supporting device for supporting and containing an abrasive element according to the present invention, said one or more protrusions penetrate corresponding one or more recesses maintaining a predetermined free space along an axis or even only one direction of said axis.

In a fourth embodiment of a supporting device for supporting and containing an abrasive element according to the present invention, two or more of said protrusions penetrate a single corresponding recess.

The various embodiments described above can also co-exist in any combination thereof.

In a particular embodiment of the supporting device for supporting and containing an abrasive element according to the present invention, said first and second coupling surface are planar. Instead, in an alternative embodiment said first and second coupling surface are not planar. In a further particular embodiment of the supporting device for supporting and containing an abrasive element according to the present invention, one or more channels that connect two or more of said recesses are present. In another particular embodiment, the supporting device for supporting and containing an abrasive element according to the present invention, comprises one or more first valves for the injection of a compressed gas and/or of a fluid into one or more free spaces inside said one or more recesses.

Alternatively, or additionally, the supporting device for supporting and containing an abrasive element according to the present invention can also comprise one or more first valves for the suction of air from one or more free spaces inside said one or more recesses.

In a further particular embodiment, the supporting device for supporting and containing an abrasive element according to the present invention comprises one or more mechanical means inserted in one or more free spaces inside said one or more recesses.

In a further aspect thereof, the present invention also relates to an abrasive tool for machining stone materials, ceramics or the like, comprising an abrasive element and a supporting device for supporting and containing said abrasive element as described above.

In practice, without prejudice to the fact that different raw materials can be used, the present solution allows the elastic response to be varied by modifying the geometries, as set forth below purely by way of example.

From the point of view of construction, recesses of different shape, dimension, number and arrangement are produced, for example in the elastomeric part, according to requirements and at the same time various protrusions, or protrusions of different shape, dimension, number and arrangement, are produced in the rigid support element, not necessarily exactly corresponding, in fact often different, with respect to those produced on the elastomer.

At this point when the two elements are coupled, preferably by gluing, a very different elastic response will be obtained depending on how the different geometries have been produced, decreasing or increasing the elastic response even significantly depending on the different zones of the assembly involved.

The embodiment described above is a preferred solution, but it could also be inverted, hence producing recesses in the rigid supporting element and protrusions on the elastomeric part or using both the solutions inside the same assembly between the different zones.

To better describe the possibilities offered by this solution, let us assume we have a Cartesian system in which the X-axis is oriented according to the radial direction of rotation of the head of the grinding machine, the Y-axis according to the normal coplanar therewith and the Z-axis according to the normal to the plane. The supporting device produced in conformity with the present invention makes it possible to choose how to modify the elastic response according to one or more of these axes or according to different orientations. In particular, it is possible to have:

deformations along the X-axis, due mainly to the centrifugal force for rotation of the head of the grinding machine (normally 600 rpm with a diameter of around 600 mm); deformations along the Y-axis (the most evident and cause of most problems) due mainly to the removal operation of the abrasive tool;

deformations along the Z-axis due mainly to the pressure exerted by the head.

It must be noted that in fact during the dynamic phase of machining, above all a result of swinging of the arms of the head, this representation is limiting. However, this simplification, when analyzed instant by instant, is very explanatory although not exhaustive.

According to the number, arrangement and possibility of coupling between the first and the second coupling means, the embodiments can be many, making it possible to obtain differentiated elastic responses depending on the materials and on the type of machining carried out.

For example, purely by way of example, some of the possible embodiments of the supporting device according to the present invention are:

i) The protrusion on the rigid support completely penetrates the recess on the elastomeric part: this results in greater rigidity in all directions.

ii) The protrusion on the rigid support penetrates the recess on the elastomeric part resting even partially only along an axis or even only one direction of the axis: this results in greater rigidity according to an axis or even only one direction of the axis while there will be a reduction along the other directions.

iii) The protrusion on the rigid support penetrates the recess on the elastomeric part with an interference that generates a preload during assembly, resting even partially only along an axis or even only one direction of the axis: this results in an even greater rigidity according to an axis or even only one direction of the axis while there will be a reduction along the other directions.

iv) The protrusion on the rigid support penetrates the recess on the elastomeric part maintaining a predetermined space along an axis or even only one direction of the axis: after a calculated deformation this results in greater rigidity according to an axis or even only one direction of the axis while there will be a reduction along the other directions. v) The conditions in points ii), iii) and iv) can coexist on the same pin even on different axes or with different orientations.

vi) Each single protrusion/recess coupling can comply with one or more of the conditions i), ii), iii), iv) and v) regardless of the condition and of the number of the other protrusion/recess couplings and have its own dimensions and characteristics adapted to achieve the best elastic response in each zone or sector or area.

vii) Each of the conditions ii), iii), iv) and v) also introduces another element of variation of the response of the system, as the gas (firstly air) trapped in the cavity that remains between the protrusion and the recess when it is compressed as a result of the deformation responds increasingly as a result of the increase in pressure, but differently to the response of the same deformation of the rubber.

viii) The condition described in point vii) can be varied by injecting, for example by means of a valve provided for this purpose, compressed gas or injecting a fluid (water, glycol, gel or the like) into one or more remaining spaces.

Alternatively, or additionally, through the same valve or through a different valve it is possible to create a vacuum pressure in one or more remaining spaces.

As further variant, it is also possible to introduce a mechanical element (such as a spring, a part made of a different material, silicone or the like) into one or more remaining spaces. In this case, the introduction of a "fourth element" (compressed gas, liquid, vacuum, mechanical element) with respect to those already present (first rigid interface element with the grinding machine, second shock absorbing element made of elastomeric material, abrasive tool) can become fundamental in the case of "dry" use where the absence of water and of its cooling and lubricating power cause, besides overheating of the abrasive (for which evidently resins with higher performances at high temperatures have been prepared) a need for greater heat dissipation together with increased mechanical strength due to the different stress and consequent greater fatigue strength, which above all in elastomers increases almost exponentially with temperature. This element or sum of several elements can be incorporated in one of the compounds or act as bridge between two or more components according to the specifications required. The elastic response and the dissipative capacity will consequently be different as a function of the element introduced and of its positioning.

ix) The condition in points vii) and viii) can be further varied by connecting, in a more or less sophisticated manner (for example, simply through a connection channel between two or more recesses or with other one- or two-way connection systems), predetermined recesses to one another according to a linear, sectorial or zonal logic, so as to obtain a given number of recesses with the same pressure (hence with the same response for the fluid component) at a given instant.

x) Penetration between protrusions and recesses can naturally occur according to larger sectors or areas where, for example, there can be several pins or protrusions inside only one recess or vice versa, or even according to very complex surfaces, where this is required.

xi) The previously described penetration can occur also starting from a supporting device in which the first rigid interface element with a grinding machine and the second shock absorbing element made of elastomeric material have a first and a second coupling surface of different in shape to the usual flat shape, for example with a surface tilted according to one or more directions, or a curved surface or having any other shape deemed suitable. This particular solution would allow the same final geometry of the assembly to be obtained using a larger amount of rigid polymer (less costly) and a smaller amount of elastomeric polymer (more costly), thereby further reducing the final cost.

xii) The condition in point ix) can be very useful in the case in which the abrasive is to be utilized in "dry" machining, i.e., without the presence of washing water. In fact, substances and/or materials with high thermal conductivity can be inserted into the spaces so as to promote the exchange between the abrasive part and the supporting part, removing energy that in the long term would lead to deterioration of the elastomeric part.

xiii) The condition in point xi) can in turn be determining in the change of ratios and dimensions between the elastomeric part and the rigid supporting part in the aforesaid case of "dry" use, also in the search for greater compatibility for dissipation of the thermal energy accumulated by the abrasive between the elastomeric part and the rigid supporting part (for example, using conductive elastomers and plastics and/or dissipative materials).

The solution proposed with the present model can reduce the effective gluing surface between the two elements with possible reduction in the tear resistance between the two elements. However, this problem can be solved by producing a small rim on one of the two elements (it is normally simpler to produce it on the non-elastomeric component but it could be on any one of the two) either outside the perimeter of the elastomeric part, or above all at each recess/protrusion coupling so that during gluing the glue is not pushed away and conveyed to the parts not in contact. Said small rim, of different height and shape depending on requirements, can be separate from the protrusion or be an integral part thereof and can also serve as centering element, thereby facilitating positioning of the two elements.

A predetermined space between said small rim (in this case preferably producing it of a height that can reach 1 or 2 millimeters or more) and the recess in the elastomeric part (or vice versa) can even allow an increase in the gluing surface with respect to the condition in use to date, and therefore achieve an even higher tear resistance.

Tests carried out in the laboratory showed that the assembly produced with one of the geometries described above, in particular with intersecting protrusions and recesses with air space variable between 0.5 and 1.0 millimeters, significantly improved the shear strength (evaluated according to the orientation of the aforesaid Y-axis), which increased from around 1 ,000 kg to over 2,000 kg, due to the fact that the stress that was sustained completely by the elastomeric part is now partly transferred from it to the rigid plastic part of the assembly. Lower deformation along the same axis with a significant reduction of the aforesaid whiplash effect is also evident. Along the Z-axis deformation was much more constant during the whole swinging oscillation.

The operating embodiment of the supporting device is determined by the type of head of the machinery and by the type of product to be ground. The rectangular shape or rectangular with beveled corners and/or the double dovetail machine attachment are therefore only one of the possible shapes, but the same logic can be used to support abrasives of different shape (for example, circular) in turn mounted on machinery with different function and different coupling.

Further characteristics and advantages of the present invention will be more apparent from the description of preferred embodiments, illustrated by way of non-limiting example in the accompanying figures, wherein:

Fig. 1 is a transparent perspective view of a first embodiment of a second shock absorbing element made of elastomeric material for coupling with an abrasive tool, of a supporting device according to the present invention;

Fig. 2 is a solid perspective view of a first embodiment of a second shock absorbing element made of elastomeric material for coupling with an abrasive tool, of a supporting device according to the present invention;

Fig. 3 is a transparent perspective view of a first embodiment of a first rigid interface element with a grinding machine, of a supporting device according to the present invention;

Fig. 4 is a solid perspective view of a first embodiment of a first rigid interface element with a grinding machine, of a supporting device according to the present invention, With reference to the accompanying figures, a supporting device for supporting and containing an abrasive element for machining stone materials, ceramics or the like according to the present invention comprises - in its most general embodiment - a first rigid interface element 10 with a grinding machine and a second shock absorbing element 20 for coupling with an abrasive tool.

One of the peculiar characteristics of the supporting device according to the present model is given by the fact that said first rigid element 10 comprises a first shaped body 1 1 having a first coupling surface 12 provided with first coupling means 13.

Likewise, the second shock absorbing element 20 comprises a second shaped body 21 having a second coupling surface 22 provided with second coupling means 23.

A further peculiar characteristic of the supporting device according to the present model is given by the fact that said first 13 and second 23 coupling means are at least partially mutually couplable in operation so as to impart a predetermined elastic response to the operating stresses imposed on said supporting device, according to the previously described operating characteristics.

Typically, the supporting device for supporting and containing an abrasive element according to the present model consists of a first rigid element 10 comprising a first shaped body 1 1 made of thermoplastic material and of a second shock absorbing element 20 comprising a second shaped body 21 made of elastomeric material. The type of rigid thermoplastic material and of elastomeric material used to produce the first 1 1 and the second shaped body 21 can be of the type conventionally used in prior art devices and can in any case be chosen as a function of application and operating requirements.

In the embodiment of the supporting device for supporting and containing an abrasive element according to the present invention, illustrated in the accompanying figures, the first coupling means 13 comprise one or more protrusions 131, 132, 133 and the second coupling means 23 comprise one or more recesses 231, 232. In practice, in this embodiment, the protrusions 131, 132, 133 are produced on the first rigid element 10, while the recesses 231, 232 are produced on the second shock absorbing element 20.

Alternatively, in an embodiment of the supporting device for supporting and containing an abrasive element according to the present invention, not illustrated, said first coupling means 13 comprise one or more recesses and said second coupling means 23 comprise one or more protrusions. In practice, in this alternative embodiment, the protrusions are produced on the second shock absorbing element 20, while the recesses are produced on the first rigid element 10.

Shapes, dimensions and positioning of the protrusions 131, 132, 133 and of the recesses 231, 232 can differ as a function of requirements and of the type of elastic response desired, also in relation to different areas of the supporting device of the present invention. For example, with reference to the accompanying figures, in the embodiment illustrated the first rigid element 10 has a first series of protrusions 131 tapered and with ovoid section arranged on the first coupling surface 12 along the longer sides of the first shaped body 1 1, a second series of protrusions 132 tapered and with cruciform section arranged on the first coupling surface 12 along a centerline of the first shaped body 1 1, and a third series of protrusions 133 tapered and with ovoid section arranged on the first coupling surface 12 at an end of the first shaped body 1 1, said protrusions 133 being of smaller dimensions with respect to said protrusions 131 and arranged with trend perpendicular with respect thereto (i.e., the major axis of the protrusions 133 is substantially perpendicular to the major axis of the protrusions 131).

The protrusions can have the same geometry as the recesses and completely penetrate corresponding one or more recesses or, as in the embodiment illustrated, they can have a different shape and only partially penetrate corresponding one or more recesses maintaining a predetermined free space along an axis or also only one direction of said axis.

In practice, as can be seen from the accompanying figures, the recesses 231, 232 have a substantially circular section, while the protrusions 131 and 133 have a substantially ovoid section. When the protrusions 131 and 133 are inserted into the recesses 231, 232 their ends located at their major axis are therefore substantially in contact with the inner walls of the recesses 231, 232 while their lateral walls are at a distance therefrom leaving a free space inside said recesses 231 , 232.

Similarly, the protrusions 132 have a substantially cruciform section and when they are inserted into the recesses 231 their ends located at the arms of the cross are substantially in contact with the inner walls of the recesses 231 creating a free space between the arms of the cross inside said recesses 231.

It can also be noted that the number di recesses present in the second shaped body 21 of the second shock absorbing element 20 made of elastomeric material is much greater than the number di protrusions present in the first shaped body 1 1 of the first rigid element 10 made of thermoplastic material. In this way, the second shock absorbing element 20 made of elastomeric material can be used with a plurality of first rigid elements 10 having different types in terms of number and/or shape and/or positioning of protrusions.

In other words, with the technical solution of the present invention, it is possible to vary the elastic response of the supporting device as a function of the operating and machining requirements using always the same shock absorbing element 20 and coupling it with first rigid elements 10 having different number and/or shape and/or positioning of protrusions, as a function of said operating and machining requirements.

This allows increased standardization of production, while maintaining a high application flexibility, significantly reducing costs and times of the production cycle of the supporting device of the present invention.

Again, with reference to the accompanying figures, in the embodiment illustrated, the second shaped body 21 of the second shock absorbing element 20 comprises a pair of channels 233 arranged linearly along opposite edges of said second shaped body 21 that connect a plurality of recesses 231 to one another. As previously mentioned, in this way the various recesses 231 connected by a same channel 233 will have the same pressure at a given instant.

The second shaped body 21 of the second shock absorbing element 20 further comprises four channels 234 arranged in a quadrilateral at the center of said second shaped body 21 that connect four recesses 231 to one another. Also in this case, the four recesses 231 connected by the four channels 234 will have the same pressure at a given instant.

The number, positioning and trend of the channels can naturally be varied, making it possible to produce zones or sectors of the second shaped body 21 of the second shock absorbing element 20 in which the pressure inside the recesses connected by a same channel is homogeneous, as a function of the operating and machining requirements.

In the embodiment illustrated in the accompanying figures, the first coupling surface 12 of the first shaped body 1 of the first rigid element 10 and the second coupling surface 22 of the second shaped body 21 of the second shock absorbing element 20 are substantially planar. However, in other embodiments it may be advantageous for said first 12 and second 22 coupling surface not to be planar. As mentioned previously, this particular solution makes it possible to obtain the same final geometry of the supporting device utilizing a larger amount of rigid polymer (less costly) and a smaller amount of elastomeric polymer (more costly) thereby reducing the final cost.

Particular embodiments of a supporting device for supporting and containing an abrasive element according to the present invention, not illustrated in the accompanying figures, can comprise one or more first valves for injection of a compressed gas and/or of a fluid into one or more free spaces inside said one or more recesses.

Alternatively, or additionally, the supporting device for supporting and containing an abrasive element according to the present invention can comprise one or more first valves for the suction of air from one or more free spaces inside said one or more recesses.

As further variant or alternative, the supporting device for supporting and containing an abrasive element according to the present invention can also comprise one or more mechanical means inserted into one or more free spaces inside said one or more recesses. As previously explained, the insertion of a "fourth element" (compressed gas, liquid, vacuum, mechanical element) with respect to those already present (first rigid interface element with the grinding machine, second shock absorbing element made of elastomeric material, abrasive tool) that allows the elastic response to be adapted as a function of requirements can be very important in the case of "dry" use where the absence of water and of its cooling and lubricating power cause, besides overheating of the abrasive, a need for greater heat dissipation together with increased mechanical strength due to the different stress and consequent greater fatigue strength.

In practice, it has been seen how with a supporting device for supporting and containing an abrasive element according to the present invention it is possible to achieve the intended objects. As can be understood from the description and from the accompanying drawings, the technical solutions adopted in the present utility model allow the tasks and the intended objects to be fully achieved, obtaining a device that is undoubtedly useful and practical to use. In particular, with a supporting device thus conceived it is possible to control and more easily contain deformations along the Y-axis (shear deformations) that are the most damaging and problematic (in fact generating the very damaging "whiplash effect"), besides varying instant by instant the pressure exerted according to the Z-axis, primary component for generation of the force from which the cutting capacity derives.

Another important advantage is the possibility of varying the elastic response as a function of the variation of the value on the X-axis, position that determines the true relative speed between tool and element to be ground. As said, this speed can vary even by 200% (as a function of the radius of rotation) and therefore the only way to generate sufficiently regular wear of the tool is to counter it with a response diversified as a function of the radius of rotation.

The present solution also adds the advantage of obtaining a modulation of the elastic response by producing, at least for the less problematic applications, a single elastomer format to couple to different rigid support formats (currently the exact opposite is necessary), making it easier to create a device with different elastic response depending whether it is used for roughing, semi-finishing, finishing and lapping grinding wheels. Given that the cost of the elastomeric part is normally 2 or 3 times higher than that of the rigid support and that the manufacturing speed of this latter is 2 or 3 times greater, it is understood that this solution allows a more flexible and rapid response with significantly lower stock.

On the basis of the description provided, other characteristics, modifications or improvements are possible and evident to a person skilled in the art. These characteristics, modifications and improvements should therefore be considered a part of the present utility model. In practice, the materials used, the dimensions and contingent shapes can be any according to requirements and to the state of the art.