"Adapter for working plates, particularly for roto-orbital and roto-eccentric sanding machines".

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DESCRIPTION The present invention concerns an adapter for working plates, particularly for roto-orbital and roto-eccentric sanding machines.

Sanding machines currently on the market comprise an internal driving mechanism with a driven part couplable with a connecting portion of a working plate. Different sanding machines (made for example by different manufacturers) need different working plates, that is the connecting portion of the working plate must be made according to the driven part of the sanding machine.

This implies that series of different working plates have to be produced for different sanding machines, and this also if these carry out the same type of working.

After a certain number of working sessions it is opportune to replace the working plate in order not to compromise the quality of the machining, so that the user is forced to purchase a series of working plates for each type of sanding machine.

On the other hand those who industrially produce working plates are forced to make different lines of production, one for each type of working plate, with a consequent increase in production costs and therefore with a consequent greater cost for the final user. In the long term the cost of working plates turns out to be much higher than the cost for the purchase of the sanding machine.

Object of the present invention is to provide an intermediate element between the sanding machine and working plate which allows to use a single type of working plate, hereinafter called standard working plate, for different types of sanding machine.

According to the invention such object is attained with an adapter for working plates, particularly for roto-orbital and roto-eccentric sanding machines characterised in that it comprises a standard coupling for standard working plates and a variable geometry coupling for connection with the driven part of a sanding machine.

To each sanding machine a respective type of adapter corresponds that is not subject to wear. To produce in series a single type of working plate, that is the standard working plate, has however lower costs as compared with several productions in series of different working plates. That results into an evident advantage for the final user that will be able to have replacement working plates faster (the production is simpler) and at lower costs.

These and other characteristics of the present invention will be made evident by the following detailed description of some embodiments thereof which are illustrated as non-limiting examples in the enclosed drawings, in which:

Figure 1 shows a partially sectioned and magnified side view of a sanding machine with a standard working plate and an adapter according to a first embodiment of the present invention;

Figure 2 shows a partially sectioned side view of the sanding machine in Figure 1 with assembled working plate and adapter;

Figure 3 shows a bottom plan view of the adapter in Figure 1;

Figure 4 shows a partially sectioned and magnified side view of a sanding machine with a working plate and an adapter according to a second embodiment of the present invention; Figure 5 shows a partially sectioned side view of the sanding machine in

Figure 4 with assembled working plate and adapter;

Figure 6 shows a side view of the adapter in Figure 4;

Figure 7 shows a top plan view of the adapter in Figure 6;

Figure 8 shows a partially sectioned and magnified side view of a sanding machine with a working plate and an adapter according to a third

embodiment of the present invention;

Figure 9 shows a partially sectioned side view of the sanding machine in Figure 8 with assembled working plate and adapter;

Figure 10 shows a side view of the adapter in Figure 8; Figure 11 shows a top plan view of the adapter in Figure 10;

Figure 12 shows a magnified section view of a variation of embodiment of the standard working plate with an adapter complementary to it;

Figure 13 shows a section view of the aforesaid variation with assembled working plate and adapter; Figure 14 shows a side view of an additional embodiment of the adapter;

Figure 15 shows a top plan view of the adapter in Figure 14;

Figure 16 shows a section view according to the line XVI-XVI in Figure 15.

A sanding machine 1 comprises an external body 2 which supports a cowling 30 and a rotary shaft 32 with eccentric 33, which causes the orbital movement of a cup-shaped driven part 4 comprising a plurality of peripheral threaded holes 5.

Said driven part 4 is couplable to a standard working plate 6 through an adapter 7 (Figures 1-3) comprising a standard coupling 8 for said standard working plate, and a coupling 9 for said driven part 4 made up of a round flat part 10 with peripheral passing through holes 11 with tapered portion.

The standard coupling 8 is made up of an externally threaded cylindrical sleeve 12 suitable to couple with an internal thread 13 of a grooved connecting portion 14 of the working plate 6. Said internal thread 13 can be a multiple thread with at least two starts, which are arranged so as to angularly overlap. The ratio between the diameter of internal thread 13 and the diameter of the external thread of the connecting portion 14 in this case must be at least equal to approximately 0.20. The adapter 7 is couplable to the driven part 4 of the sanding machine 1

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through fastening screws 15 with tapered head which insert into the holes 11 in order then to engage into the threaded holes 5.

In a second embodiment (Figures 4-7) the adapter 7 has the coupling 9 for the connection with the sanding machine 1 made up of a flat part 16 with raised central portion 34 passed through by a passing through hole 17 with variable diameter with shoulders 18.

The driven part 4 of the sanding machine 1 has a female threaded hole 19 suitable to couple to a fastening threaded pin 20 passing through said hole 17 of the adapter 7 with the interposition of a washer 21. In a third embodiment (Figures 8-11) the adapter 7 has the coupling 9 for the connection with the sanding machine 1 made up of a substantially flat part 22 with threaded pin 23 in a single piece, couplable with a threaded hole 24 of the driven part 4 of the sanding machine 1.

A washer 25 mediates the contact between the flat part 22 and the driven part 4 of the sanding machine 1.

In Figures 12-13, as compared with Figures 1-3, an embodiment of the adapter 7 and the working plate 6 is shown in which the coupling 8 has an internal thread 40 couplable with a corresponding variation of the connecting portion 14 of the working plate 6, which includes a cylindrical sleeve 41 with external thread 42. In short the male-female coupling between the adapter 7 and the working plate 6 is reversed thus becoming female-male.

Similar variation can be provided for the embodiments in Figures 4-7 and 8-11. In Figures 14-16 finally a variation of the adapter in Figures 8-11 is shown in which the flat part 22 has in addition a side contoured surface 31 which is engageable manually or with suitable fastening mean for the assembly/disassembly of the working plate 6. Similar solution can be provided for the adapters 7 in Figures 1-3, 4-7 and 12-13. From the description of the aforesaid embodiments it is possible to

evince that a standard working plate 6 is assemblable onto different sanding machines that is having different controlled parts 4 owing to the use of the adapter 7 which has a standard coupling 8 and one 9 with variable geometry.