FOR WORKING SURFACES AND RELATED REMOVAL METHOD

Field of the invention

The present invention relates to the field of the machines used for working surfaces that are able to move an abrasive element in the space, according to at least two degrees of freedom, and in particular it relates to an apparatus for removing an abrasive element in a machine for working surfaces .

Furthermore , the invention relates to a method for carrying out such removal .

Background of the invention

As known, in order to carry out the finishing operations of the surfaces made of pottery, wood, plastic materials , metallic materials , etc . in order to improve their shape , and the accuracy of the measurement and improve their tribological properties , sanding or grinding machines are normally used provided with an abrasive element , typically an abrasive disc .

In particular, the sanding or grinding operations are , normally, carried out by hand by a worker who grasps a manual sander or grinder, and moves the abrasive disc with respect to the surface to be worked . More precisely, in the machines of known type , the abrasive disc i s constrained to a support commonly known as "backing pad" , which is moved by an electric motor or compressed air . Usually, a di f ference is made between orbital sanders , where the abrasive element is moved by the backing pad, in order to cause more or less large circular movements , and roto-orbital sanders , where a rotational motion is added to the orbital motion . In this way, it is possible to carry out a finishing of the worked surfaces of higher quality .

In addition to the manual machines , automatic industrial machines also exist where the abrasive disc or other abrasive element is moved with respect to the surface to be worked by an anthropomorphic arm, or anyway, by a support mounted on guides in such a way that is possible to move the abrasive element at least according to two di f ferent movement directions . The abrasive element can be constrained to the backing pad, or more generally to the support , in di f ferent ways , for example by Velcro or adhesive tape , or also by means of a threaded connection . Normally, the threaded connection is provided between a threaded blind hole made in the support , and a threaded shaft of which the abrasive element is provided at the face opposite to the face that , in working conditions , exerts the abrasive action . A widespread type of threaded connection between the backing pad and the abrasive disc, usually known in the technical field as "ROLOC" system, is , for example , described in US3562968 .

Both in case of manual machines and in case of automatic machines , after a determined number of working cycles , it is , however, necessary to replace the abrasive element , which, unavoidably, during the work, wears out and, therefore , is not anymore able to exert an ef fective polishing action .

Normally, the replacement of the abrasive element is an operation carried out by hand by a worker with consequent loss of time and productivity of the machine . Furthermore , the replacement by hand of the abrasive element could lead to the risk to incorrectly apply the new abrasive disc to the support with the possibility that , during the working, the abrasive disc can move away from the correct working position and to compromise the operation .

In order to overcome the aforementioned disadvantages in WO2015/ 125068 an apparatus able to automatically carry out the replacement of an abrasive element is provided . In particular, the solution described in WO2015/ 125068 provides a removal action where a removal device operates that is provided with a sharp edge . A displacement device is , furthermore , provided to move the support with respect to the removal device up to reach a removal position where the sharp edge is positioned between the abrasive element and the support and, therefore , causes the abrasive element to be detached from the support . Normally, in these machines is , furthermore , provided at least a detection device in order to veri fy that the removal action has been correctly made , in order to avoid that the displacement device can position the support body at an application station with the abrasive element that i s still engaged to the backing pad, condition which would prevent a new abrasive element from being applied, or that the backing pad, not provided with the abrasive element owing to a missing correct positioning of the new abrasive element on the same , can be moved at the surface to be worked with the risk to damage the same .

However, the solution described in WO2015/ 125068 like other removal devices of known type , are not satis factory, in particular i f the abrasive element and/or the backing pad are made of a " soft" material i . e . it shows a determined pliability i f subj ect to a determined pressure . In this case , in fact , the device which separates the abrasive element from the backing pad, in particular the element with the sharp edge , is not able to exert an ef fective removal action exactly because during the removal action, the abrasive element and/or the backing pad "buckles" under the pressure exerted by the same thus compromising, in practice , the removal action . Another type of situation where the solution of WO2015/ 125068 , like other similar removal devices of known type , is not ef fective is the case in which the backing pad cannot be kept in a position fixed with respect to the working head of the machine to which is engaged, and is free to rotate with respect to the same .

Another example of a prior art machine with analogous drawbacks is described in US2021 /276153 .

Summary of the invention

It is , therefore , an obj ect of the present invention to provide an apparatus for removing an abrasive element in a machine for finishing surfaces , in particular a sandpapering, or a polishing, or a grinding machine , which allows to overcome the aforementioned drawbacks of the prior art solutions . It is another obj ect of the present invention to provide such an apparatus which is able to quickly and accurately remove the abrasive element from the respective support , or backing pad, of the machine for finishing surfaces .

It is a particular obj ect of the present invention to provide an apparatus for removing an abrasive element in a machine for finishing surfaces in the case that the abrasive element and/or the support body or backing pad are made of a " soft" material , i . e . having a determined pliability .

It is another particular obj ect of the present invention to provide an apparatus for removing an abras ive element in a machine for f inishing surfaces that is ef fective also in the case that the support body or backing pad is free to rotate during the removal action with respect to the working head to which is engaged .

It is also an obj ect of the present invention to provide a method for removing an abrasive element in a machine for finishing surfaces , in particular a sandpapering machine , or a polishing machine , or a grinding machine having the aforementioned advantages with respect to the method of the prior art .

These and other obj ects are obtained by a machine for finishing surfaces , according to the invention, comprising :

- a support body configured to removably engage an abrasive element having a perimeter edge delimiting an abrasive surface , said support body and said abrasive element being, respectively, provided, at respective engagement surfaces with f irst and second engagement members configured to move from an engagement configuration to a disengagement configuration, and vice versa ;

- a displacement device configured to move said support body in the space according to at least 1 degree of freedom;

- an apparatus for removing said abrasive element from said support body; whose main characteristic is that said apparatus for removing said abrasive element from the support body comprises a removal group provided with at least a removal member configured to rotate about a rotation axis in a predetermined direction of rotation, said or each removal member being provided with a removal surface configured to cause said first and second engagement members to move from said engagement configuration to said disengagement configuration; that the displacement device is configured to position the abrasive surface of the abrasive element in contact with the aforementioned removal surface at a predetermined removal zone with a predetermined starting inclination with respect to said rotation axis ; and that the predetermined starting inclination i s such that the removal member i s adapted to cause said first and second engagement members to move from the engagement configuration to the disengagement configuration starting from a perimeter portion adj acent to the aforementioned perimeter edge .

Other technical characteristics of the invention and related embodiments are defined in the dependent claims .

Advantageously, the aforementioned removal surface can be configured to engage the second engagement members o f the engagement surface of the abrasive element .

In particular, a barrier member can be , furthermore , provided positioned downstream of the removal zone with respect to the direction of rotation of the or each removal member . More in particular, the barrier member can be configured to be positioned between the abrasive element and the or each removal member during the removal of the abrasive element from the support body .

Advantageously, the or each removal member can be provided with a cylindrical surface having the generatrices parallel to the rotation axis .

In particular, the removal group can comprise :

- a first removal member adapted to rotate about the aforementioned rotation axis ;

- at least a second removal member adapted to rotate about the aforementioned rotation axis .

More in particular , the first and second removal members can be positioned at a predetermined distance ( d) .

In a possible embodiment of the invention, the aforementioned predetermined distance ( d) between the first and the at least second removal member coincide con the width of a groove , in particular coaxially arranged to the aforementioned rotation axis , made at a single cylindrical body .

Advantageously, the aforementioned groove is a circular groove .

More in particular, the f irst and the at least second removal member can be obtained by making at least a circular groove of predetermined depth starting from the aforementioned cylindrical body and wherein the aforementioned predetermined depth of the groove is less than the depth of the cylindrical body which will be mounted on the aforementioned rotation shaft . Therefore , in this case , the rotation shaft , at the or each circular groove is not exposed .

Alternatively, each removal member can be a separate element which is mounted on the aforementioned rotation shaft and positioned at the aforementioned predetermined distance ( d) from the adj acent member . In this case , in general , the portion of the shaft arranged between the two removal members following one another will be exposed .

Advantageously, the barrier member can comprise at least a protruding portion adapted to be positioned between the first and the second removal member at the aforementioned circular groove .

In particular, the displacement device can be configured to cause the support body to move from the predetermined starting inclination to a predetermined final inclination which is less than the predetermined starting inclination during the aforementioned removal action carried out by the removal group .

More in particular, the predetermined final inclination is substantially parallel to the rotation axis .

Advantageously, the barrier member can comprise a main portion, in particular inclined at a predetermined angle with respect to the rotation axis , and at least a portion protruding from said main portion adapted to be pos itioned between the first and the second removal member .

In a possible embodiment , the aforementioned barrier member can comprise a main portion inclined at a predetermined angle with respect to said rotation axis from which are adapted to protrude :

- a first protruding portion positioned between the first and the second removal member ;

- a second and a third protruding portion positioned at opposite sides with respect to said first and second removal members .

In particular, a blocking device can be , furthermore , provided configured to block the rotation of the support body about the aforementioned rotation axis during the removal of the abrasive element by the removal group .

Advantageously, the removal group can comprise , furthermore , a stretching member configured to stretch the abrasive element , during the removal carried out by the or each removal member, avoiding that the same can form folds , or wrinkles , thus j amming the or each removal member .

In particular, the stretching member can be configured to rotate about a rotation axis , advantageously parallel to the rotation axis of the or each removal member . More in particular, the stretching member can be configured to rotate about the aforementioned rotation axis in a direction opposite to the direction of rotation of the or each removal member about its axis .

Advantageously, during the removal of the abrasive element , the stretching member can be positioned at a distance from the support body greater than the distance at which the or each removal member is positioned .

In an alternative embodiment provided by the invention, the aforementioned removal surface of the removal member can be substantially flat .

In particular, the removal member can be a di sc configured to rotate about the rotation axis .

According to another aspect of the invention, a method for removing an abrasive element having a perimeter edge delimiting an abrasive surface in a machine for finishing surfaces comprises the steps of :

- providing a support body configured to removably engage said abrasive element , said support body and said abrasive element being, respectively, provided, at respective engagement surfaces of the first and second engagement members configured to move from an engagement configuration to a disengagement configuration, and vice versa ;

- moving said support body in the space according to at least 1 degree of freedom by a displacement device ; whose main characteristic is that a step is , furthermore , provided for removing said abrasive element from said support body, said step for removing comprising the steps of :

- rotating at least a removal member about a rotation axis in a predetermined direction of rotation, said or each removal member being provided with a removal surface configured to engage said second engagement members of said engagement surface of said abrasive element at a removal zone in order to cause said first and second engagement members to move from said engagement configuration to said disengagement configuration;

- positioning by said displacement device said abrasive surface of said abrasive element in contact with said or each removal member at a predetermined removal zone with a predetermined starting inclination with respect to said rotation axis , said predetermined starting inclination being such that said removal member is adapted to cause the first and second engagement members to move from the engagement configuration to the di sengagement configuration starting from said perimeter edge .

Brief description of the drawings

The invention will be now illustrated with the following description of an exemplary embodiment thereof , exempli fying but not limitative , with reference to the attached drawings wherein :

Fig . 1 diagrammatically shows a side elevation perspective view of a possible embodiment of an apparatus , according to the invention, for removing an abrasive element in a machine for finishing surfaces ;

Fig . 2 diagrammatically shows a side elevation exploded perspective view of a possible embodiment of a working head of which the machine for finishing surfaces can be equipped to highlight some technical characteristics ;

Figures from 3 to 6 diagrammatically show a side elevation perspective view of a possible sequence of steps carried out by a first embodiment of the apparatus , according to the invention, for removing an abrasive element from a support body;

Figures from 7 to 13 , 15 and 16 diagrammatically show side elevation perspective views of some alternative embodiments provided by the invention for the apparatus according to the invention for removing an abrasive element from a support body;

Fig . 14 diagrammatically shows an enlargement of figure 13 to highlight some technical characteristics ;

Figures from 17 to 20 diagrammatically show side elevation perspective views of further alternative embodiments of the apparatus according to the invention for removing an abrasive element from a support body in a machine for finishing surfaces ;

Fig . 21 diagrammatically shows a side elevation perspective view of a further alternative embodiment of the apparatus , according to the invention, for removing an abrasive element from a support body in machines for finishing surfaces ;

Fig . 22 shows an enlargement of a portion of the apparatus of figure 21 to highlight some technical characteristics ;

Fig . 23 diagrammatically shows a side elevation view of still another alternative embodiment of the apparatus , according to the invention, for removing an abrasive element from a support body in machines for finishing surfaces ;

Fig . 24 diagrammatically shows a side elevation perspective view the apparatus of figure 23 ; Fig . 25 shows an enlargement of a portion of the apparatus of figure 24 to highlight some technical characteristics ;

Fig . 26 diagrammatically shows a side elevation view partly sectioned of the apparatus of figure 23 .

Detailed description of some exemplary embodiments o f the invention

In figure 1 , an apparatus 100 is diagrammatically shown, according to the invention, for removing an abrasive element 20 provided with a perimeter edge 26 delimiting an abrasive surface 22 , in particular adapted to carry out a polishing action at the surface to be worked, in a machine 1 for finishing surfaces . The machine 1 comprises , in particular, a support body or backing pad 10 , for example integral to a working head 50 , configured to removably engage the abrasive element 20 . More precisely, the support body 10 and the abras ive element 20 are , respectively, provided, at respective engagement surfaces 13 and 23 , of first and second engagement members 15 and 25 configured to move from an engagement configuration to a disengagement configuration, and vice versa . In particular, the engagement surface 23 of the abrasive element 20 is arranged at the opposite side of the aforementioned abrasive surface 22 .

In an embodiment provided by the present invention, the aforementioned first and second engagement members 13 and 23 can be , respectively, first and second portions of predetermined si ze of a hook-and- loop fastener adapted to removably engage to each other, al so called, respectively, "male Velcro" and " female Velcro" . Alternatively, the aforementioned first and second engagement members 13 and 23 can be adapted to provide a snap- fit engagement . In this case , the first engagement members 13 can comprise at least a protrusion 13 and the second engagement members at least a recess 23 , or vice versa .

The machine 1 comprises , furthermore , a displacement device 40 configured to move the support body 10 in the space according to at least 1 degree of freedom .

In particular, the displacement device 40 can be configured to move the support body 10 according to one or more rotational degree of freedom, or according to a combination of movements comprising at least a translational degree of freedom and at least one rotational degree of freedom and, altogether, according to a number of degrees of freedom between 2 and 6 . In an embodiment provided by the invention, the displacement device 40 can be an anthropomorphic robot .

In particular, the displacement device 40 can be configured to cause at least a rotation motion o f the support body 10 about a rotation axis 101 with respect to the working head 50 . The machine for finishing 1 can be also a roto-orbital machine and, therefore , the displacement device 40 can be configured to move the support body 10 , in such a way that this follows an eccentric orbit with respect to the axis of the working head 50 .

According to what is provided by the present invention, the apparatus 100 comprises , furthermore , a removal group 70 provided with at least a removal member 75 configured to rotate about a rotation axis 175 in a predetermined direction of rotation . In particular, the or each removal member 75 can be provided with a removal surface 76 configured to cause the first and second engagement members to move from the engagement configuration to the di sengagement configuration, advantageously starting from a perimeter portion 27 adj acent to the aforementioned perimeter edge 26 . The displacement device 40 is , advantageously, configured to position the abrasive surface 22 of the abrasive element 20 in contact with the aforementioned removal surface 76 at a removal zone 71 with a predetermined starting inclination ai with respect to the rotation axis 175 ( diagrammatically shown in figure 3 ) . More in particular, the predetermined starting inclination ai can be such that the removal member 75 is adapted to cause the first and second engagement members 15 and 25 to move from the engagement configuration to the disengagement configuration starting from the perimeter portion 26 .

Advantageously, the removal group 70 can provide a rotation shaft 77 on which each removal member 75 is mounted . The rotation shaft 77 can be adapted to rotate about the aforementioned rotation axis 175 operated by a motor 95 , for example an electric motor . In particular, the motor 95 can be operatively connected to the rotation shaft 77 by a motion transmission group 96 diagrammatically shown with a block in the figures . The motion transmission group 96 can comprise , for example , a determined group of gears , not shown in the figure for simplicity, for example a pinion mounted on the axis of the motor 95 adapted to mesh with a toothed wheel coaxially arranged to the rotation shaft 77 , or a first pulley coaxial to the axis of motor 95 and a second pulley coaxial to the rotation shaft 77 , also these not shown in the figures for simplicity, connected by a motion transmission member , for example a belt , or a transmission chain, or analogous known motion transmission gears able to cause the rotation by a motor o f a rotation shaft about its rotation axis .

In particular, the aforementioned rotation shaft 77 can be operatively connected to a support structure , for example a wall 121 of a collecting container 120 where the abrasive members 20 are collected once removed from the support body 10 . More in particular, the collecting container 120 can have an inlet mouth 125 positioned below the removal group 70 through which the abras ive members 20 fall by gravity once removed from the support body 10 .

Advantageously, the displacement device 40 , during the removal step, is adapted to move the support body 10 along a advancing direction 110 , in particular substantially orthogonal to the generatrices of the or each removal member 75 . In particular, the aforementioned predetermined direction of rotation 176 of the or each removal member 75 , can be such to be opposed to the advancing direction 110 of the support body 10 with respect to the removal member 75 ( see figures 4 and 5 ) . More in particular, the aforementioned predetermined direction of rotation 176 o f the or each removal member 75 can go from the support body 10 to the abrasive element 20 . More precisely, i f the support body 10 move the abrasive element 20 adj acent to the removal surface 76 from the left, the aforementioned direction of rotation 176 is, advantageously, counterclockwise. Instead, if the support body 10 move the abrasive element 20 adjacent to the removal surface 76 from the right, situation that is, for example, diagrammatically shown in figure 1, the aforementioned direction of rotation 176 is, advantageously, clockwise.

In this way, the removal surface 76 is adapted to hit the abrasive element 20 at the perimeter edge 26 causing the abrasive element 20 to move away from the support body 10.

Advantageously, the displacement device 40 can be configured to move the support body 10 from the predetermined starting inclination ai up to a predetermined final inclination af, less than ai, during the removal action by the removal group 70 (diagrammatically shown in figure 5) . In particular, the aforementioned starting inclination can be comprised between 15° and 75°, More in particular between 15° and 60°, advantageously between 20° and 50°, preferably comprised between 25° and 45°, for example equal to 30°. More in particular, the aforementioned predetermined final inclination af, can be, instead, substantially parallel or parallel to the rotation axis 175, i.e. the surface of the support body 10 from which the abrasive element 20 has been removed, can be substantially parallel to the aforementioned rotation axis 175.

In an embodiment provided by the invention, the removal surface 76 can be a surface with a high friction. In particular, the removal surface 76 can be a knurled surface or made of a material with a high friction, for example rubber .

In a preferred embodiment , the removal surface 76 can be equipped with third engagement members , not shown in the figure for simplicity, configured to engage with the second engagement members 23 o f the abrasive element 20 . For example , the third engagement members can provide , like the first engagement members 13 , at least a portion of " female Velcro" , or "male Velcro" . In the first case , the second engagement members 23 will be formed by at least a portion of "male Velcro" . In the second case , instead, the second engagement members 23 will be formed by at least a portion of " female Velcro" . Analogously, in the case that the first and second engagement members 13 and 23 provide at least a protrusion 13 and at least a recess 23 , or vice versa, adapted to provide a snapengagement with each other, the third engagement members 73 will provide , respectively, a protrusion or a recess .

The or each removal member 75 can be provided with a cylindrical surface having the generatrices parallel to the rotation axis 175. In this case , therefore , the removal zone 71 is defined downstream of the generatrix at which the displacement device 40 is adapted to move the abrasive element 20 in contact with the removal surface 76 .

In a preferred embodiment of the invention diagrammatically shown for example in figure 7 , the removal group 70 comprises a first removal member 75a and at least a second removal member 75b adapted to rotate about the rotation axis 175 . More in detail , the first and second removal members 75a and 75b are positioned at a predetermined distance d one from the other . In particular, the first and the at least second removal member 75a and 75b can be two distinct bodies mounted on the rotation shaft 77 to the aforementioned predetermined distance d, or belongs to the same cylindrical body on which at least a groove is made having a width equal to the aforementioned predetermined distance d, in particular a circumferential groove 73 .

As diagrammatically shown in particular in the figures from 3 to 7 , the removal group can comprise , furthermore , a barrier member 80 , advantageously positioned downstream of the removal zone 71 with respect to the direction of rotation 176 of the or each removal member 75 . Advantageously, the barrier member 80 can be configured to be positioned between the abrasive element 20 and the or each removal member 75 during the removal of the abrasive element 20 dal support body 10 .

In particular, the barrier member 80 can comprise a main portion 81 from which at least a protruding portion 85 is adapted to protrude in order to be positioned, in use , between the first and the second removal member 75a and 75b, advantageously at the circumferential groove 73 .

As diagrammatically shown in the figures 9 and 10 , in an embodiment of the invention, the barrier member 80 can comprise a main portion 81 inclined at a predetermined angle p with respect to the rotation axis 175 . In particular, from the main portion 81 a first , a second and a third protruding portion 85 can protrude . More in particular, the first protruding portion 85 can be positioned between the first and the second removal member 75a and 75b, whilst the second and the third protruding portion can be positioned at opposite sides with respect to the first and the second removal member 75a and 75b .

The presence of the barrier member 80 and, in particular, of the protruding portions 85 of this , allows to avoid that once the abrasive element 20 is removed from the support body 10 for the action of the removal surface 76 , it can be retained by the same remaining at the or each removal member 75 thus avoiding that a following removal action of another abrasive element 20 can be carried out a . More precisely, the presence of the barrier member 80 avoids that the abrasive element 20 can get caught between two removal members 75a and 75b following to each other, or that can get stuck between them and the shaft causing their rotation about the axis 175 thus requiring to stop the machine for removing the abrasive element 20 by hand .

In particular, the number of removal members 75 of the removal group 70 can be even more than 2 . For example , as diagrammatically shown in figure 11 , the removal group 70 can comprise a first , a second and a third removal member 75a, 75b and 75c . In this case , the barrier member 80 can comprise a first , a second, a third, a fourth and a f i fth protruding portion 85 positioned at the opposite ends o f the removal group 70 and between two removal members 75a, 75b and 75b, 75d following to each other, in particular at respective circumferential slots or grooves 73 .

In the further alternative embodiment diagrammatically shown in figure 12 , the removal group 70 comprises a first , a second, a third and a fourth removal member 75a- 75d . In this case , the barrier member 80 can comprise a first , a second, a third, a fourth and a fi fth protruding portion 85 positioned at the opposite ends of the removal group 70 and between two removal members 75a, 75b ; 75b, 75c and 75d following to each other, in particular at respective circumferential slots or grooves 73 . Still as diagrammatically shown in figure 12 , the barrier member 80 can provide an engagement portion 82 to engage the same to a support surface , for example the internal surface of the container body 120 , i f present .

As the skilled person in the art will have no di f ficult to understand, the number of removal members 75 , like the number of protruding portions 85 of the barrier member 80 will be , in general , decided according to the characteristics of the abrasive element 20 to be removed and/or of the type of support body 10 , in particular according to the geometric and functional characteristics of these components .

As diagrammatically shown in the figures 13 and 14 , the aforementioned removal group 70 can comprise at least an elastic element 90 , for example a linear spring, or a torsional spring . More in particular, the rotation shaft 77 of the or each removal member 75 can be configured to slide , or rotate , with respect to a support structure , for example a wall of the container body 120 , opposed by the or each elastic element 90 . In this way, the removal group 70 can move with respect to the support structure , but in a controlled way, because corresponding to the elastic force applied by the or each elastic element 90 , during the removal action .

As diagrammatically shown as an example in figure 13 , the rotation shaft 77 can be mounted on a support structure comprising for example a first and a second bearing 94a and 94b associated respectively to a first and a second support rod 93a and 93b sliding along respective sliding directions 193a and 193b about which a first and a second linear spring 90a and 90b are , respectively, wound . These oppose the aforementioned sliding of the support rods 93a and 93b during the removal action .

As diagrammatically shown in figure 14 with reference to the embodiment of figure 13 , but the same inventive concept can be , however, applied also to the other embodiments described above and diagrammatically shown in the figures from 1 to 16 , the or each removal member 75 can comprise a main body, or anima, 71 covered by a layer of the aforementioned material with high friction, or provided with the third engagement members , described above .

As diagrammatically shown in figure 15 , the removal group 70 can provide at least a first and a second removal member 75a and 75b configured to rotate about 2 distinct rotation axes 175a and 175b . In particular, the first and the second removal member 75a and 75b can be mounted on respective rotation shafts 77a and 77b operated by a motor or by a respective motor 95a and 95b through a respective motion transmission group 96a and 96b . More in particular, the first and the second removal member 75a and 75b can be adapted to rotate about the respective rotation axes 175a and 175b in a first and in a second direction of rotation opposite to each other . In particular, each removal member 75a and 75b can be associated to a respective barrier member 80a and 80b . Notwithstanding in figure 15 only one removal member 75 for each rotation shaft 77 is shown, the skilled person in the art will have no di f ficult to understand that the embodiments described above with reference to the figures from 1 to 14 can be , however, adopted .

In a possible embodiment of the invention, the removal group 70 can provide at least a removal member 75 configured to rotate about the rotation axis 175 in a first or in a second direction of rotation . This can be , for example , obtained by a motor 95 of electric type by reversing the direction of the current supplied to the windings of the same . This solution can be useful in the applications of the invention in particular typologies of abrasive members 20 , in particular having very small thicknesses whereby i f the abrasive element 20 is subj ected to an inversion of the direction of rotation, it is possible to guarantee that it is disengaged from the support body 10 .

In the further embodiment diagrammatically shown in figure 16 , the removal group 70 comprises a first and a second rotation shaft 77a and 77b, at least one of which operated by a motor to cause it to rotate about its axis 175 . In this case , di f ferently from the embodiments described above , the removal member 75 provided with the removal surface 76 can be a member sliding between the first and the second rotation shaft 77a and 77b . Each rotation shaft 77a and 77b can be provided with at least a cylindrical support member adapted to rotate integrally to the respective rotation shaft 77a and 77b and to support the aforementioned removal member 75 .

It is suitable to note that notwithstanding a lot of the figures from 1 to 16 show the abrasive element 20 and the support body 10 having a circular geometry, the present invention can be also applied with analogous advantages also to machine 1 provided with support bodies 10 and abrasive members 20 having a di f ferent geometry . At this regard, as an example in figure 8 it i s diagrammatically shown the case of an abrasive element 20 having a substantially triangular shape applied to a support body having a substantially rectangular geometry .

The technical solution provided by the present invention and described above with reference to the figures from 1 to 16 is particularly ef fective for machines for finishing surfaces such as grinders , sanders , polishers , etc . , where the support body 10 is not blocked to the displacement device and, therefore , during the removal step is free to rotate about a longitudinal axis . The aforementioned technical solution, di f ferently from the prior art solutions , is particularly ef fective also in the case that the support body 10 and/or the abrasive element 20 is made of a soft material , i . e . pliable , i f subj ect to a determined pressure .

As diagrammatically shown in figure 17 , in a further embodiment of the invention, the removal group 70 can, furthermore , comprise a stretching member 72 configured to stretch the abrasive element 20 , during its removal by the or each removal member 75 . In this way it is possible to avoid that the abrasive element 20 can form folds or wrinkles during the action of the or each removal member 75 , situation that could cause the or each removal member 75 to be j ammed and, therefore , the need to stop the machine in order to remove the same by hand with a great loss of time and productivity .

In particular, the stretching member 72 , for example substantially cylindrical shaped, can be configured to rotate about a rotation axis 172 , advantageously parallel to the rotation axis 175 o f the or each removal member 75 . More in particular, the stretching member 72 can be configured to rotate about the aforementioned rotation axis 172 in a predetermined direction of rotation 173 , advantageously a direction of rotation opposite to the direction of rotation 176 o f the or each removal member 75 about its axis 175 .

Advantageously, the stretching member 72 can be positioned at a distance from the support body 10 greater than the or each removal member 75 . In particular, the rotation of the stretching member 72 about its rotation axis 172 can be caused by the same motor 95 operating the rotation of the or each removal member 75 . This can be obtained, for example , by a motion transmission group 96 configured to transmit to both the rotation shafts 77 and 78 the rotation motion of the motor 95 . For example , the rotation group can comprise , according to an embodiment that is not shown in the figures for clarity reasons , a couple of toothed wheels which mesh with each other, one of which operatively connected to the rotation shaft of motor 95 , in particular to a pinion mounted on the shaft of the motor 95 .

In an alternative embodiment that is diagrammatically shown in figure 18 in the case of a first and a second removal member 75a and 75b, each rotation shaft 77 and 78 can be operated by a respective motor 95 and 95 ' .

Advantageously, the stretching member 72 can be made of a material having a high friction coef ficient , for example rubber, or can be covered by a layer of the aforementioned material . Alternatively, the stretching member 72 can be provided with rilievi , for example obtained by knurling . In this case , the stretching member 72 can be made of a plastic or metallic material .

As diagrammatically shown in the figures 19 and 20 , in a further alternative embodiment of the invention, a blocking device 90 can be , furthermore , provided configured to block the rotation of the support body 10 about its rotation axis 101 during the removal o f the abrasive element 20 . In particular, the blocking device 90 can be configured to act from the side of the abrasive surface 22 . More in particular, the blocking device 90 can comprise a support portion 91 and a contact portion 92 , advantageously rotatably connected to the support portion 91 , for example by a hinge 95 , in such a way to be free to rotate about a rotation axis 195 . More precisely, during the removal action by the removal group 70 , the support portion 91 is adapted to translate from/towards the abrasive element 20 to force the contact portion 92 against the abrasive surface 22 . In this way, during the removal action, the contact portion 92 rotates about the rotation axis 195 and exerts a blocking action o f the rotation of the support body 10 about the rotation axis 101 .

In an embodiment that is not shown in the figures for simplicity, the blocking device 90 can be configured to exert the blocking action of the rotation of the support body 10 about the rotation axis 101 from the opposite side with respect to the abrasive element 20 .

According to another embodiment , instead, the blocking of the rotation of the support body 10 about the rotation axis 101 can be obtained by blocking, for example by a control group, the rotation shaft , or a transmission gear, which causes its rotation .

In particular, a check apparatus , not shown in the figures for simplicity, can be , furthermore , provided configured to check the presence or absence of the abrasive element 20 at the support body 10 . More in particular, the check of the presence or absence of the abrasive element 20 on the support body 10 , can provide that the aforementioned displacement device 40 moves the support body 10 , and, i f present , the abrasive element 20 to it engaged, in contact with a control surface of a control member . Then, the displacement device 40 is operated in such a way to cause the support body 10 to move , for example to translate along a predetermined direction, or to rotate , or a combination of movements . In general , however, the displacement device 40 can be adapted to apply a predetermined force , in particular a detachment force , to move the support body 10 away from the control member .

More in particular, the check apparatus also provides a detection device configured to detect any engagement between the support body 10 and the aforementioned control member . In particular, the detection device is configured to carry out the aforementioned detection, once that the support body 10 , or the abrasive element 20 that is in case engaged to it , has been positioned in contact with the control member and has been moved by the displacement device 40 . More in detail , in a possible embodiment , the detection device can be configured to detect the force applied by the displacement device 40 on the support body 10 , or the control member, to move the support body 10 with respect to the control member . The detection device can, advantageously, comprise at least a movement sensor and/or at least an accelerometer and/or at least a rotation sensor and/or at least an encoder and/or at least a limit position sensor .

Preferably, the check apparatus can be of the type described in W02021 / 005499 in the name of the same Applicant .

As diagrammatically shown in figure , a reference surface 61 can be , furthermore , provided having a known spatial position . In particular, the displacement device 40 , advantageously before positioning the abrasive element 20 at the or each removal member 75 can be configured to position the abrasive surface 22 of the abrasive element 20 adj acent to the reference surface 61 . The displacement device 40 , in particular a control group associated to it , acquire , then, the known spatial position of the reference surface 61 as spatial position of the abras ive surface 22 . In this way, it is possible to know with high accuracy the spatial position instant by instant of the abrasive element 20 engaged to the support body 10 during its movement by the displacement device 40 .

Notwithstanding in the figures from 1 to 20 , the collecting container 120 is always shown having an inlet mouth 125 positioned at a top wall 121 of the container body 120 , in an alternative embodiment of the invention that is diagrammatically shown in figure 21 , the inlet mouth 125 of the collecting container 120 can be positioned at a lateral wall 122 of the container body 120 .

In particular, the collecting container 120 can be provided with at least a guide wall 123 conf igured to guide the removed abrasive element 20 towards the inlet mouth 125 of the collecting container 120 .

As diagrammatically shown in figure 21 , in an embodiment provided by the invention, the reference surface 61 can be positioned close to the rotation shaft 77 of the or each removal member 75 , for example at one or more support members 60 of the same .

In the figures from 22 to 26 further embodiments of the apparatus 100 , according to the invention, for removing the abrasive element 20 from the support body 10 , are diagrammatically shown . More in detail , in the embodiment diagrammatically shown in the figures from 22 to 26 , the removal surface 76 of the removal member 75 i s substantially flat . For example , the removal member 75 can be a disc configured to rotate about the rotation axis 175 , in particular coaxially to the aforementioned disc 75 . Preferably, as anticipated above for the embodiment where the removal surface 76 era substantially cylindrical , also in this case , the removal member 75 can be provided with at least a groove 73 coaxial to the rotation axis 175 . In particular, in the case of disc 75, each groove 73 is preferably a circular groove . In general , the disc 75 will be provided with a plurality of circular grooves 73 . Therefore , the di f ferent removal portions in which the circular grooves 73 divides the removal member 75 form the aforementioned removal surface 76 substantially flat .

As shown in detail in the figures 25 and 26 , also in this case is , advantageously, provided at least a barrier member 80 positioned downstream of the removal zone , or however of the beginning of the removal , of the abrasive element 20 and comprising at least a protruding portion 85 , preferably a plurality of protruding portions , each of which configured to be positioned between two removal portions 76 following to each other of the removal member 75 , that means at a respective circular groove 73 . In this way, on the one hand, the presence of the barrier member 80 does not hamper the rotation of the removal member 75 about the rotation axis 175 . The combined action of the removal surface 76 , which pushes on the abrasive element 20 once that is removed from the support body 10 , and the barrier member 80 causes the abrasive element 20 removed from the support body 10 , to move away from the removal zone .

The main portion 81 of the barrier member 80 can be inclined at a predetermined angle p with respect to the rotation axis 175 of the removal member 75. In particular, angle p can be comprised between 10° and 80°, advantageously between 20° and 60°, preferably between 30° and 50°, for example equal to 45°.

As diagrammatically shown in the figures from 23 to 26, the apparatus 100 for removing an abrasive element 20 from a support body 10, according to the invention, provides a support frame 105 on which the removal member 75 and the related operating devices are mounted, in particular the motor 95 and the transmission gears 96 which transmit the motion of the motor shaft 95 about the axis 195 of the removal member 75 to cause the rotation about the rotation axis 175. In particular, also the barrier member 80 can be mounted on the aforementioned support frame 105.

The foregoing description of a specific embodiment will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such an embodiment without further research and without parting from the invention, and it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.