The present invention concerns an abrasive body intended for surface processing, a support for the abrasive body and a machine comprising said abrasive body and support.

It is well known that for many years past there have existed in the market numerous surface-processing devices that by means of the movement of some abrasive body are capable of finishing the surfaces of a wide range of objects, including furniture, wooden articles or rubber, plastic or metal parts of, for example, automobiles or other articles.

In particular, the processing that these devices are intended to carry out are substantially surface-finishing operations (grinding adjustments, smoothing, polishing, removal of working residues, etc.) and operations to prepare the surfaces for such further processing as painting, gluing and the like.

In particular, the machines known today essentially consist of a frame to which the user can attach a supporting element intended to receive the abrasive body and to be set in rapid motion to enable it to carry out the processing operation.

In other words, such surface processing machines will be equipped with a means for producing movement, typically an electric or pneumatic motor, that will apply the motion it generates to the support

and therefore also to the abrasive body via an appropriate transmission shaft.

The device may also be provided with appropriate gripping elements by means of which the user may hold and guide it while carrying out the processing operations on the object to be processed.

When the machine is switched on, the support and the abrasive body are set in motion and the operator can carry out the necessary operations by bringing the abrasive body into contact with the surface to be finished.

A first problem associated with the machines briefly described above is bound up with the fact that-by their very nature-operations of processing surfaces by means of abrasion inevitably imply the creation of dust particles as a result of the material that is removed during the operation.

With a view to obviating this difficulty, the machines of this type produced and marketed in the more recent past have often been provided with appropriate suction systems that generate a depression in the area of the support and the abrasive body, so that the abraded particles can be sucked up from the working zone and led away via appropriate channels or ducts in the support.

In particular, the said suction is generally made possible because both the support associated with the machine frame and the abrasive body are provided with appropriate suction holes.

According to the type of material that is to be processed, as also the suction force and the type of machine involved, the number and the layout of these holes can vary very considerably.

It should however be noted that these devices (i. e. machine-support- abrasive body systems), even though they are widely available in the market, are associated with a number of drawbacks and/or operating limitations.

First of all, it should be noted that the typical surface that has to be processed will not be perfectly flat and/or that the processing may have to be carried out at the edges or corners of the surface or on surfaces on which it is not possible to rest the whole of the abrasive body.

In such situations it is readily obvious that only some of the holes in the abrasive body will effectively come to be placed in the processing zone; the remaining suction holes, on the other hand, will be situated away from the processing surface and also from the dust generated by the processing. Consequently, the suction force will inevitably and disadvantageously be greater where there is no resistance to the passage of the air, that is to say, at the holes situated away from the processing zone.

Fundamentally this implies that the suction of the material will occur at the holes situated away from the processing surface and therefore also away from the zones where the abraded dust particles are to be found.

The limit just explained can obviously prove harmful to the health of the operator, since he will be working in an environment that has not been cleansed of the dust material generated during the processing; it can lead to cleaning problems in the work area and may also imply problems bound up with the fact that the abraded particles will remain on the surface that has to be processed, where they will cause obstruction and thus reduce the efficiency of the processing.

Furthermore, the very presence of these suction holes appreciably diminishes the active surface of the abrasive body available for removing material from the surface, thus inevitably reducing the work output that can be obtained from it as compared with a similar body devoid of such holes.

Lastly, the presence of holes only in some parts of the abrasive body may imply that some of the abraded particles are not sucked away and will therefore remain between the abrasive body and the surface to be processed, creating a layer of abraded material in the truest sense of the term and therefore an obstruction for the abrasive body that will reduce the latter's efficiency.

Lastly again, the holes in the abrasive body and in the support require to be exactly superimposed in order to cause complete dust suction and avoid abrasive body gumming.

In such situations it is the principal scope of the present invention to substantially obviate the drawbacks that have just been described.

The scope of the present invention is therefore to make available an abrasive body, together with a support that utilizes the said abrasive

body and/or to which the said abrasive body can be applied, capable of providing a targeted suction and therefore assuring a very substantial increase of the efficiency of the abrasive body and/or the abrasive body-support combination and/or the machine-abrasive body-support combination. A further scope of the invention is to attain the aforementioned objectives without complicating the structure of the machine-support combination and without necessarily having to increase the suction power and therefore also the energy consumption and the costs associated therewith.

Another scope of the invention is that of making available an abrasive body that is simple to produce, implies substantially limited costs and, while yet improving the efficiency, does not have any of the operating drawbacks associated with the abrasive bodies marketed today.

These scopes, as well as others that will become more apparent in the course of the present description, are substantially attained by an abrasive body capable of being associated with surface processing machines and with the support for the abrasive body with which such machines are provided, all as described in the claims that follow the present description.

Further characteristics and advantages of the invention will become more readily apparent from the detailed description of a preferred but not exclusive form of an abrasive body in accordance with the present invention.

The said description will be given hereinbelow, making reference to the attached drawings, which are furnished solely by way of example and are not to be considered limitative in any manner or wise, where: Fig. 1 is a view of a machine of the known type to which an abrasive body in accordance with the present invention can be attached; Fig. 2 is a view of the abrasive surface of an abrasive body in accordance with the present invention; Fig. 2a is an enlarged detail of the abrasive body shown in Figure 2; Fig. 3 is a view of the abrasive surface of the abrasive body shown in Figure 2 in which there are indicated some possible outlines of the cuts ; Fig. 4 is a view of the abrasive surface of the abrasive body of an implementation variant of the abrasive body shown in Figures 2 and 3; Fig. 5 is a further implementation variant of the abrasive body in accordance with the present invention; Fig. 6 is a diagrammatic view in exploded form of an implementation version of a machine-support-abrasive body combination in accordance with the present invention; Fig. 7 illustrates possible means of connecting the abrasive body to a support and Fig. 7A illustrates a variant of the means of connection shown in Figure 7.

In the figures set out above the reference number 1 is used to indicate the whole of an abrasive body in accordance with the present invention.

Making reference to Figure 1, a brief description will now be given of a surface processing machine 5 to which the abrasive body 1 may be attached, but this description will be kept very brief (since the machine is of a known type).

Typically such a machine 5 is designed to receive as a rigid attachment a support 10 that can be moved by means of appropriate motion generators, the machine being also capable of generating suction with the help of appropriate suction means that are in common use today.

It is clear that the implementation form of the suction means 15 may differ according to whether it is decided to use an appropriate suction pump or, as in the implementation example shown in Figure 1, it is decided to use a self-sucking machine to create a depression into chamber 16 above the support 10 to which the abrasive body 1 is attached.

Obviously, we shall not here go into the implementation details of the two construction forms briefly outlined above, because they are both of a known type and are widely marketed and used.

If we now pass on to examining Figures 2 to 5, we may note that the abrasive body that is the object of the invention has an active face 2a that, in operating conditions, is intended to be turned towards the surface to be processed.

In particular, the said active face is provided with appropriate abrasive means 3 (Fig. 2a) that are intended to assure the actual surface processing when the abrasive body is set in motion.

The abrasive body 1 may or may not be provided with appropriate connecting means 4,4A (see Figs. 4,5,6 7) that make it possible for the said abrasive body to be attached to the support.

In this connection it should be underscored that the abrasive body 1 in accordance with the invention may be used either on its own in a manual manner, or mounted in either a fixed or a detachable manner on the support 10 and again used in a manual manner, or, thirdly, mounted on a support 10 that, in its turn, is attached to the machine 5 and can therefore be set in motion by the motorial means forming part of the said machine.

It is obvious that the connecting means 4A (for attaching the abrasive body to the support 10) can assume a very wide variety of forms, always provided that they make it possible for the abrasive body 1 to be firmly attached to the support 10 (see Figures 6 and 7, for example) in such a manner that any movement of the support 10 will have as its counterpart an identical movement of the abrasive body 1.

Known examples of connecting means are strap-type or self-adhesive attachments 4A as shown in Figures 6,7 and are mechanical-type attachments 4 as shown in Figure 7A.

In other words, with reference to Fig. 7, the support 10 has an operating surface 10a turned towards the abrasive body 1 (and

also towards the surface to be processed) and is provided with an appropriate lining to enable it to become engaged with the corresponding engagement face 2b of the abrasive body 1.

A further implementation form is illustrated in Figure 4, where the connecting means 4 consist of a predetermined number of engagement tabs (fins, tongues, winglets) intended to be connected to the support 10 (see Fig. 7A).

In particular, on the abrasive body there are four perforated tabs 9 intended to engage with the corresponding attachment elements on the support 10.

It is further clear that any other connecting means could be provided to assure that the support 10 and the abrasive body 1 will move substantially in unison.

Considering the construction details of the abrasive body, one may note that it is provided with a predetermined number of substantially passing cuts 6 defined by the respective flaps 7,8 lying side by side.

It should also be noted that the abrasive body, possibly of a laminar conformation, namely very thin, is made of flexible material.

In particular, a first inventive concept underlying the present invention is that of avoiding the formation of holes, possibly but not necessarily circular in shape, through which suction can be generated during the operating phases of the combination constituted by the support and the abrasive body.

The support 10 may be of compact material integral or not with the abrasive body 1 and is provided with holes for allowing passage of the abraded particles entered from the cuts 6 of the abrasive body.

In other words, the abrasive body 1 is devoid of passing cavities other than the aforesaid cuts, which are closed when the abrasive body is in a plane condition, thus assuring optimal functioning of the combination constituted by the support and the abrasive body, as will be explained in greater detail further on.

As may be seen from the drawings attached hereto, the cuts 6 may have different shapes; for example, the cuts may be curved in shape (Figs. 2 and 2a), and could also be substantially triangular or rectangular (Fig. 3) or of other geometrical shapes, always provided that the two flaps that define the cut should be lying appropriately side by side, thus assuring that the abrasive body is free of openings.

Given the illustrated realization shapes of the cuts 6, these cuts are therefore defined by the two flaps lying side by side and forming part of one and the same abrasive body 1, where the first flap 7 is convex, while the second flap 8 is concave.

The cuts 6 may be distributed in the entire surface or only in a part of it, and their arrangement could be either regular or irregular.

Furthermore, the said cuts 6 could be oriented either in the same direction or in different directions.

But the reason why all the cuts have preferably the orientation with respect to the rotation direction A as shown in Fig. 2 is to avoid that the flaps 7 open because of a hit of their edges against a projection

encountered on the piece under processing.

In this manner the topology of the cut is such as to maintain the cuts stably in their closed condition.

Having made clear the above, we can now pass on to describing the functioning of the abrasive body 1 in greater detail, specifying also the advantages that can be gained by its use.

Once the abrasive body 1 has been placed on the support 10 and the latter has been attached to the machine, setting into motion also the suction that is to act on the support 10, the particular conformation of the abrasive body 1 is such that the flaps 7,8 defining the cuts 6 come to lie side by side in the position in which the cuts are closed, thus substantially preventing the effects of the suction action.

The cuts that are situated in parts of the abrasive body not in contact with the processing surface will still be in their normal closed positioning in which the suction force cannot become effective.

In other words, the use of the abrasive body in accordance with the present invention ensures that only the cuts actually situated in the processing area will open by the pressure of the abraded particles that are eliminated subsequently by the suction action.

In particular the support body 10 may be provided with a plurality of holes so as that at least some of the cuts 6 are directly superimposed to them in operating condition (see fig. 7). The above mentioned

superposed cuts opens when deformed by the pressure exerted by the dust which is on the surface to be abraded.

When the abrasive body is being used on surfaces that are not rectilinear, on edges and, quite generally, on objects where only parts of the abrasive body are actually in contact with the processing surface, two working conditions will typically be generated: in a first zone not in contact with the processing; where there are no forces acting on the abrasive body, the cuts are in their closed condition and the suction, not being able to act through the abrasive body, will therefore remain ineffective, in a second, the actual working area (i. e. where the abrasive body is in contact with the processing surface), the cuts opened by the pressure of the abraded particles will be in their open position, thus allowing the suction to become effective and to remove the dust and the abraded particles.

The invention produces some important advantages.

Firstly, it optimizes the dust-suction process without in any way creating constructional complications.

In other words the invention permits the opening of only those cuts actually situated in the working area and therefore in the area where it is desirable to have an effective suction force. At all other points, i. e. the parts of the abrasive body not in contact with the processing surface, these cuts remain in their closed position and do not permit the suction force to become effective.

Secondly, the abrasive body has an absolutely homogeneous structure and is not discontinuous as in the case of abrasive bodies of

the known type, which are full of holes ; this necessarily implies a greater abrasive surface and therefore a better performance.

Furthermore, the opening of the cuts in the zones where the abrasive body is in contact with the processing surface prevents abraded particles from accumulating on the abrasive surface of the abrasive body under the effect of the suction and thus improves its efficiency.

Over and above this, it should be noted that the cost of realizing the abrasive bodies are not increased, nor does the operator have to take any special measures when he uses them.

The particular layout pattern of the cuts (though, obviously, only in the case of abrasive bodies intended to be used with a rotary motion) makes it possible to avoid any kind of problem due to hit or undesired opening of the two flaps, so that in actual practice the user will not experience any problems.