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1. (WO2019043618) METHOD FOR FASTENING A ROTARY ABRASIVE TOOL TO A SPINDLE AND FASTENING DEVICE THEREOF
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METHOD FOR FASTENING A ROTARY ABRASIVE TOOL TO A SPINDLE AND

FASTENING DEVICE THEREOF

DESCRIPTION,

The present invention relates to a rotary polishing tool. In particular, the present invention refers to a rotary polishing tool provided with an abrasive body which can be engaged for polishing flat plates. In more detail, the present invention refers to a rotary polishing tool provided with an abrasive body which can be engaged for polishing flat plates and provided with a coupling device designed to transmit torque and to provide axial support to the abrasive body for being assembled and disassembled with an axial movement.

DESCRIPTION OF THE PRIOR ART

In the field of machines, which can be used for polishing flat plates or tiles, it is known to equip operative stations with heads provided with a plurality of rotating tools and arrange means that determines the relative translation motion of the plates/tiles in respect to these heads. Normally, these heads are mobile transversally to the development direction of the plates or tiles and each tool is provided with a prismatic member, not necessarily axial-symmetric shape. Said member is formed with the abrasive material, normally but not exclusively felt, plastic material having a similar function as the "Scotch Brite®", manufactured and sold by the multinational 3M®, natural filaments of the Tampico type, also manufactured in polyurethane resin. Furthermore, said prismatic member, that normally, but not necessarily, has a cylindrical shape, but can also have a lobe shaped cross-section, is carried by a rigid disc, normally metal, which acts as a mechanical interface designed to transmit the torque upon operation of the head that carries the tool.

Therefore, said disc confers to the prismatic member and, therefore to the tool as a whole, the ability to polish the surface of the material to be treated. On the other hand, the tool comprises an adapter that enables the disc to be connected to each type of coupling present on the toolholder head of the polishing machine. Normally the connection between the two members takes place through at least a threaded connection, that has the respective axis parallel to the pivot axis of the tool. Each connection, due to its own nature, performs two functions: supports the disc, and therefore the abrasive member, and transmits the torque to the disc and thus to the abrasive prismatic member. Said adapter is connected to the disc through at least a threaded connection. The working life of a tool is measured in m2, and the average working life of a tool is 10.000m2, which the tool achieves in around 2 to 3 days, based on the type of work to be carried out and on the pressure that is exerted on the plates being worked. Considering that polishing machines have at least 10 satellite heads, each of which has at least 6 satellites and, that each abrasive disc is connected to the satellite by at least 4 screws, it is easy to understand that the disassembly and reequipping step of each toolholder head of each polishing machine requires unscrewing and subsequently rescrewing at least 24 screws, one by one, and that an activity of this type imposes a machine standstill time which does not fit with the need to saturate the operating time of the machine, in order to increase its yield per time unit and therefore enable competitive prices useful for generating sufficient margins that allow to develop such activity and remain on the market in a profitable manner. On the other hand, the reequipping step is normally completed by separating the metal disc from the abrasive member, normally connected by gluing, before its relative disposal, in order to both comply with regulations on differentiated collection of industrial waste, and for recovering expenses, given that the metal discs can be sold individually on the market. In regard to what has been described above, currently no solution has been found for the problem of using new generation tools usable equipping the heads of polishing machines for flat plates, when these machines are provided with groups of tools rotatable around axes perpendicular to the plates/tiles to be treated, so as to saturate the working capacity of these machines and, the problem of substantially changing the manner in which one proceeds with the reequipping of the heads. The aim of the applicant is, on the other hand, to obviously widen his/her market as well as facilitate the recovery of noble materials such as steel without burdening the activity of the operators.

In consideration of the situation described above it would be desirable to have tools that, in addition to limiting and possibly overcoming the typical inconveniences of the previously mentioned prior art, are constructed with parts made of non-metal materials and subject to wear which are cheaper, designed for being reconditioned through operations that are simple and quick to carry out in short times even by personnel that are unqualified to use machine tools for industrial use.

Rotary polishing tools are known from the documents of the prior art CN 205 630 308 U, US 2015/251295 Al and WO 2010/071618 A1.

SUMMARY OF THE PRESENT INVENTION

The present invention relates to a rotary polishing tool. In particular, the present invention refers to a rotary polishing tool provided with an abrasive body which can be used for polishing flat plates. In further detail, the present invention refers to a rotary polishing tool provided with an abrasive body usable for polishing flat plates and provided with a coupling device designed to transmit torque and provide axial support to the abrasive body so that it can be assembled and disassembled with an axial movement.

An aim of the present invention is to achieve a rotary polishing tool that is both free of the inconveniences of the prior art described above, as well as having a simple construction, long lasting, cheap and the parts of which are recyclable at very low costs.

According to the present invention a rotary tool is provided, the main characteristics of which will be described in at least one of the claims that follow.

A further aim of the present invention is to provide a method for equipping a rotary polishing toolholder head for a polishing machine for polishing flat surfaces that are both easy and quick to implement.

According to the present invention a method is furthermore provided for equipping a rotary polishing toolholder head of a polishing machine for flat surfaces the main characteristics of which will be described in one of the claims that follow.

BRIEF DESCRIPTION OF THE FIGURES

Further characteristics and advantages of a rotary polishing tool for a multi-tool head of a polishing machine for flat surfaces and of the reequipping method according to the present invention will become clearer from the following description with reference to the enclosed drawings that show some non-limiting examples of implementation, in which identical or corresponding parts of the device are denoted by the same reference numbers. In particular:

- Figure 1 is an elevation side view of a machine that carries a plurality of rotary tools according to the present invention;

- Figure 2 is an exploded view of a detail of figure 1;

- Figure 3 is an exploded view of a first variation of figure 2; and

- Figure 4 is a view of a structural detail of a second variation of figure 2.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

In figure 1, number 1 denotes, as a whole, a plurality of rotary tools 1 for a multi-tool head H of a polishing machine MU for flat plate or tile surfaces L. The tool, that in figure 1, is represented having an axial-symmetric shape in respect to its own axis A, has in particular a cylindrical shape. In any case, the tool 1 has a base 10 that rigidly carries an abrasive body 20 through an adhesive connection, or the like, and comprises an adapter 30 arranged for connecting the base 10 to a respective rotating spindle M of the head H around a pivot axis A. The base 10 has a cylindrical crown coaxial to the axis A, with a thickness equal to the thickness of the base 10 and peripherally protruding from the abrasive body 20 by a constant radial width so as to form an annular edge 12. With particular reference to figure 2, each tool 1 comprises coupling members 40, designed to connect the abrasive body 20 to the adapter 30 through the respective annular edge 12. Said coupling members 40 comprise, in particular, an annular fastening member 42 shaped in a similar manner as the annular edge 12 in order to be coup1able with the latter in a conjugated manner, as shown in figure 1. Always with reference to figure 2, the annular member 42 has a service hole 420 axially engageable by the abrasive body 20 for keeping the respective annular edge 12 in contact with the adapter 30 in a sandwich-like manner.

In particular, the base 10 comprises a flat disc 10' made of a plastic material and the annular member 42 comprises a substantially circular flat ring 42' the outer diameter of which is substantially identical to an outer diameter of the disc 10', whereas the outer diameter approximates, by excess, an outer diameter of the annular body 20.

The annular edge 12 has a plurality of first cylindrical through holes 120, that are peripherally distributed in a substantially consistent manner. The adapter 30 is also made of a metal material of the ferromagnetic type and so is the ring 42' . The latter also has a plurality of second cylindrical through holes 420, that are substantially identical and distributed similarly to the first holes 120, so that the first holes 120 and the second holes 420 are positionable so as to axially face each other.

The adapter 30 also has a first outer edge 32 that is provided with a plurality of first cylindrical members 3200, each of which is provided with an end 3201 made of a magnetic material and connected by screws to a respective body 3203. In addition, it can be useful to specify that each first cylindrical member 3200 is delimited by a cylindrical surface that approximates, by defect, a diameter of the first holes 120 and of the second holes 420 and is made of a magnetic material. Furthermore, the cylindrical members 3200 achieve first protrusions 320 that are arranged to engage first holes 120 and the second holes 420, so that the adapter 30 is able to transmit torque to the disc 10' and, definitively, to the same abrasive body 20. Due to this, the axial extension of the first cylindrical members 3200 exceeds a length calculated as a sum of the thicknesses of the annular edge 12 and of the ring 42' .

In regard to what has been described above, by manufacturing the disc 10' in a plastic material, the adapter 30 and the ring 42' in metal material and by providing the adapter 20 with first cylindrical members 3200, each provided with a magnetic end 3201, it is possible to axially counteract the action of gravity acting on the abrasive body 20 by supporting it in a sandwich-like manner between the adapter 30 and the ring 42' through the respective annular edge 12. The use of bodies 3202 of the first cylindrical members 3200 allows to transfer the torque from the spindle M to the abrasive body 20.

The use of the tool 1 is easy to understand from what has been described above and doesn't require further explanation. In any case, it can be useful to specify that the use of a rotary polishing tool shaped as the tool 1 described above decisively allows to simplify the step of equipping the heads H of the respective polishing machine that is carried out by making gestures exclusively directed along the axial direction. In particular, the method comprises a first step of arranging the disc 10' (that carries the abrasive body 20) facing the adapter 30 associated with the spindle M of a polishing machine by carrying the annular edge 12 (of the same disc 10') with the respective first holes 120 in axial projection with the first cylindrical members 3200. This step is followed by a step of axially moving the disc 10 '/the abrasive body 20 in order to position the first cylindrical members 3200 inside the first holes 120 : until bringing the corresponding disc 10' into abutment against the adapter 30. The method therefore comprises a step of arranging the ring 24 ' facing the respective second holes 420 in projection with the first cylindrical members 3200; a step of positioning the first cylindrical members 3200 inside the second holes 420 of the ring 42' until bringing the latter into axial abutment against the annular edge 12. At this point the magnetic interaction between the first cylindrical members 3200 and the ring 42* keeps the disc 10' and therefore the abrasive body 20 in an axially correct position for carrying out the polishing operation. In particular, the first cylindrical members 3200 determine the support of the disc 10* and the rotation of the ring 42' and of the intermediate annular edge 12 and, therefore of the abrasive body 20 rigidly connected thereto. Obviously, the disassembly method of the discs 10' provided with abrasive bodies 20 is carried out backwards, and will be completed by a step of peeling the abrasive body 20 from the disc 10' to which it was previously glued in a simple and practical manner.

It is easy to understand that the combination of concave and convex shapes together with the physical interaction between magnetic and ferromagnetic structural components determines the possibility of supporting the active part of the tool 1 and of applying to the latter the working torque needed to carry out the polishing of the plates below the equipped heads H.

It is clear that modifications and variations can be made to the tool 1 described and illustrated herein, without departing from the scope of the present invention.

For example, with reference to figure 3, the adapter 30 and the ring 42' can be modified in terms of shape, leaving the role of the driving member and driven member unaltered. In particular, the adapter 30, made with an annular part overlapping a disc, has a plurality of third cylindrical through holes 322 (dual functioning of the first cylindrical members 3200) substantially identical and distributed similarly to the first holes 120 and the annular body 42' has a plurality of second protrusions 422 (dual functioning of the holes 420), each of which is shaped similarly to the first cylindrical members 3200 for engaging the first holes 120 and the third holes 322, thus comprises a second cylindrical member 4220 with a diameter that approximates, by defect, a diameter of the first holes 120 and the third holes 322 and has at least a respective end made of magnetic material.

On the other hand, the adapter 30 and the disc 10' have angular reference elements on the respective opposite faces for limiting the angular orientation of the disc 10' in respect to the adapter 30 to only two geometrically equivalent positions, as they are symmetrical in a polar manner. In particular for this aim, the adapter 30 has a pair of ridges 31 arranged symmetrically in respect to the axis A (only visible in figure 3 for simplifying the drawing operation with a broken line) and to the disc 10', a pair of holes 101 diametrically opposite at the same radial distance of the ridges 31 and shaped in a substantially conjugated manner with the latter by shape coupling.

In this case, the method that can be followed for reequipping a spindle M with a substantially identical tool to the last one described above, comprises a first step of arranging the abrasive body 20/disc 10' facing the adapter 30 bringing the first holes 120 of the corresponding annular edge 12 to face the third holes 322 of the adapter 30. Said step is preceded by a step of opposing and interpenetrating, so as to face, the two holes 101 of the disc 10' and the two ridges 31 of the adapter 30. The method further comprises a second step of fitting the ring 42' onto the abrasive body 20 with the second cylindrical members 4220 inside the first holes and third holes 322 until bringing the disc 10' into axial abutment with the adapter 30 and the ring 42' .

In addition, in the case where it is preferred to avoid the use of ferromagnetic metals for constructing the adapter 30 and the ring 42' and, of the magnetic material for producing the first protrusions 320 and/or the second protrusions 422, an axial limitation of the movement of the abrasive member 20 in respect to the adapter 30 could be determined by achieving a connection through interference transversal to the axis A between the ring 42' and the first cylindrical members 3220, or the second cylindrical members 4220, by making a circular groove 321 in said cylindrical members, as shown in figure 4. Said groove 321, which must be measured in height, has a longitudinal extension equal to the thickness of the ring 42' and must be made spaced from the adapter 30 that approximates the thickness of the annular edge 12 in order to determine the packet connection of the disc 10' to the adapter 30 upon an axial rotation of the disc 10' around an axis A, either clockwise or anticlockwise, so that the ring 42' is designed to become an axial abutment for the abrasive body 20. In this manner, the correct locking of the disc 10' and therefore of the abrasive body 20 in respect to the head H is guaranteed independently of the rotation direction conferred by the heads H to the tools 1, as the grooves 321 are angular.

In regard to what has been described above, each type of tool 1 described above is manufactured with parts, made of a non-metal material and subject to wear, therefore at limited costs and according to logics of energy recovery for the simple peeling of the abrasive body 20 from the disc 10', which can be implemented in a simple and quick manner. This makes the tool 1 overall particularly cheap, given that its metal components, which are expensive, are all reusable without the need to buy them again or repair them, while their respective wear parts can be recycled at minimum costs. Therefore, refurbishing of each individual tool 1 is achievable through operations that are simple and quick to carry out in short times even by personnel that are unqualified to use tools of polishing machines for industrial use.