Unit for polishing bevels on the edges of glass plates, particularly on numeric-control machines

The unit for polishing the bevels on the edges of glass plates, particularly on a numeric-control machine, comprises a cup grinding wheel for polishing the edge of a glass plate and the like. The particularity of the unit is constituted by the fact that it comprises, inside the cup grinding wheel, at least one opening for introducing a mix of cerium oxide and water and, on the outside of the cup grinding wheel, an interspace which surrounds the cup grinding wheel and is connected to a suction unit.

BACKGROUND OF THE INVENTION 
The present invention relates to a unit for polishing bevels on the edges 
of glass plates, particularly on numeric-control machines. 
It is known that during the manufacture of glass plates multiple treatments 
are performed in succession at the edge of the plate, using different 
grinders to produce in succession the grinding or shaping of the bevel and 
ending with the polishing operation. 
In conventional treatment methods, the various devices are preset to 
perform a specific treatment; in particular, currently commercially 
available machines form a partly polished edge or bevel with polishing 
grinders which use the same water used for grinding. 
Actual polishing is then performed on other machines, using a mix of water 
and cerium oxide, which must be present in very specific percentages. 
With these machines it is possible to recuperate the mix of cerium oxide 
and water, which is relatively expensive, so as to reuse, in practice, the 
same mix in a closed cycle. 
Automatic or numeric-control machines used for the treatment of glass 
plates can conceptually perform, on a single device, the automatic 
succession of the various operations, since the treatment head is capable 
of automatically replacing the grinder, thus allowing to perform all the 
required treatment steps. 
However, with this kind of device there is the problem of polishing, since 
the mix of water and cerium oxide used for polishing cannot be mixed with 
the water used for grinding, both because the mixing percentages would be 
altered and because one would use a mix contaminated by glass powder, 
which would produce scratches on the glass during polishing. 
The other solution, i.e., to use a mixture of cerium oxide and water which 
is not recycled but disposed, is not practicable since cerium oxide has a 
relatively high cost. 
Accordingly, the principle of the numeric-control machine is severely 
penalized; said machine should inherently be able to produce a perfectly 
finished product, but in practice it requires the transfer of the product 
to another machine to perform the final polishing operations. 
SUMMARY OF THE INVENTION 
The aim of the present invention is indeed to eliminate the drawbacks 
described above by providing a unit for polishing the edges of glass 
plates which can be applied to numeric-control machines and allows to 
perform, directly on the numeric-control machine, the polishing operation 
as well, without however losing the mixture of water and cerium oxide, 
which can instead be recycled. 
Within the scope of this aim, a particular object of the invention is to 
provide a polishing unit in which it is possible to recycle the cerium 
oxide, with the assurance that it is not contaminated by particles 
produced by the previous grinding operations, thus achieving a truly 
optimum end result. 
Another object of the present invention is to provide a unit for polishing 
the bevels of glass plates which, through its particular constructive 
characteristics, is capable of giving the greatest assurances of 
reliability and safety in use. 
Another object of the present invention is to provide a unit for polishing 
the edges of glass plates which can be easily obtained starting from 
commonly commercially available elements and materials and furthermore is 
competitive from a purely economic point of view. 
This aim, these objects and others which will become apparent hereinafter 
are achieved by a unit for polishing the bevels on the edges of glass 
plates, applicable particularly to numeric-control machines, according to 
the invention, which comprises a cup grinding wheel for polishing the edge 
of a glass plate and the like, characterized in that it comprises, inside 
said cup grinding wheel, at least one opening for introducing a mix of 
cerium oxide and water and, on the outside of said cup grinding wheel, an 
interspace which surrounds said cup grinding wheel and is connected to a 
suction unit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
With reference to the above figures, and particularly to FIG. 1, the unit 
for polishing the edges of glass plates, particularly in numeric-control 
machines, comprises a cup grinding wheel 1 which acts frontally and is 
made of felt in a per se known manner. 
The cup grinding wheel 1 is connected to the conical wheel spindle 2, which 
is automatically picked up in a numeric-control machine which changes the 
tools during the various treatments. 
The particularity of the invention is constituted by the fact that a 
completion body 3 is associated with the conical wheel spindle 2 and is 
rotatably connected to the tang 4 of the conical wheel spindle by 
interposition of ordinary bearings 5. 
The completion body has a duct 10 which can be connected to a unit for 
introducing the mix of water and cerium oxide, which in a possible 
embodiment is provided axially in the tang 4 and leads into an opening 11 
which is arranged inside the cup grinding wheel 1; obviously, other 
embodiments can be provided, but in any case they must feed the mix of 
cerium and water into the inside of the cup grinding wheel. 
With this arrangement, the mix, due to centrifugal force, is induced to 
pass over the inner face of the grinding wheel and then beneath the front 
face of the grinding wheel, which forms the treatment region. 
An important characteristic of the invention is constituted by the fact 
that outside the grinding wheel 1 there is a suction chamber 20 delimited 
by an elastic strip 21 which protrudes slightly with respect to the active 
edge of the grinder 1 and is connected to a suction duct 22 which connects 
to the treatment head when the polishing grinder is inserted and allows to 
aspirate the cerium oxide mix after it has been used, since the interspace 
20 completely surrounds the cup grinding wheel and the resulting suction 
prevents the mix from falling onto the machine and being wasted and 
instead returns it, perfectly clean, to a specifically provided container. 
In order to compensate for the consumption of the cup grinding wheel, the 
elastic strip 21 is supported by axially adjustable means, such as for 
example a ring 23 which can be positioned with respect to the completion 
body 3. 
With this solution, in practice a closed circuit is provided for the mix, 
which remains perfectly clean at all times and perfectly separated from 
the circuit for the water used during abrasion grinding. 
Another solution conceptually related to the above described one, as shown 
in FIGS. 2-4, uses suction means constituted by suction arms 30 which are 
supported by the treatment head 31 and end with semicircular suction 
sectors, designated by the reference numeral 32, which can be positioned, 
as shown in FIG. 3, to the side of the grinder 1, repeating the above 
described solution. 
The arms 30 can oscillate or are in any case movable so that they can be 
shifted away from the region where grinding wheel changing occurs, so that 
they avoid causing any hindrance and can be moved closer only when the 
presence of the suction chamber is required in order to recover the cerium 
oxide mix. 
As shown schematically in FIG. 5, the circuit has a delivery unit, 
designated by the reference numeral 40, which draws from a reservoir 41 
and feeds the cerium oxide mix into the grinding wheel 1, whilst the 
suction arms 30 are connected to a suction unit 42, which recycles the mix 
to feed it back into the reservoir 41. 
Conceptually, therefore, it is evident that the inventive concept consists 
in providing either a suction chamber, which is directly connected to the 
conical wheel spindle that surrounds the cone and is automatically 
connected to the delivery of the cerium oxide and to the suction when the 
conical wheel spindle is connected, or a conceptually similar solution, in 
which aspirating sectors are associated with the assembly of the treatment 
head and are moved towards the polishing cup grinding wheel at the time of 
use and are moved away when the polishing function is completed, in order 
to allow to change the tools and use them. 
In practice, the particularity of the invention consists in having a 
suction system which is applied at the active grinding wheel when it must 
perform its function and can be disconnected when it is not required, thus 
allowing to perform tool changing without any hindrance or manual action, 
accordingly making the operation of a numeric-control machine particularly 
efficient. 
It should also be added that suction units are applied to already 
commercially available machines, but these suction units, which have a 
fixed position, are simply able to surround a portion of the grinding 
wheel, purely to avoid wetting and abundantly dirtying the machine with 
water in the region where the tool makes contact with the glass; in the 
above described embodiment, the suction chamber is instead arranged so 
that it is in close contact with the entire peripheral region of the 
grinding wheel which is treating the glass. 
The invention thus conceived is susceptible of numerous modifications and 
variations, all of which are within the scope of the inventive concept. 
All the details may furthermore be replaced with other technically 
equivalent elements. 
In practice, the materials employed, so long as they are compatible with 
the specific use, may be any according to requirements.