Machine for machining edges, particularly of glass plates

The machine for machining edges, particularly of glass plates, includes, on a supporting structure, mutually opposite conveyors which extend continuously and are suitable for moving the plates to be machined at machining heads. At least one of the conveyors has a plurality of adjacent sliding blocks each of which includes an elongated supporting body on which a covering is provided which has blocks for gripping the plates being machined. The elongated supporting body has, inside it, a T-shaped seat for slidingly retaining and guiding a rod-like element to which a pad is connected; the pad can be arranged at a presettable distance from the blocks, which have a fixed vertical placement with respect to the machining surface.

BACKGROUND OF THE INVENTION 
The present invention relates to a machine for machining edges, 
particularly of glass plates. 
As is known, machines for machining the edges of glass plates, such as for 
example chamfering machines, generally have, on a supporting structure, a 
pair of opposite conveyors which extend continuously and retain the plate, 
arranged edgeways, between them; said plate must be moved to be machined 
on machining heads which generally have grinders which protrude upward 
from the machining table. 
In order to allow the accommodation of the machining heads, the sliding 
blocks which retain the glass plates and are provided on the continuously 
extending conveyors must therefore remain at a certain distance from the 
machining surface, since they would otherwise interfere with the machining 
heads. 
It is also known that in some cases it is necessary to machine the edges of 
small glass plates. 
Accordingly, in order to try to solve this problem, solutions have already 
been provided which in practice entail a sliding block which can move with 
respect to the conveyor along a direction which is substantially 
perpendicular to said conveyor advancement direction, so that it is 
possible to retain even small plates. 
However, this solution creates considerable disadvantages, since the guides 
for the translatory motion of the sliding blocks, which are moved 
monolithically, are unavoidably subjected to very heavy wear, being 
exposed to the machining dust and waste, which is generally composed of 
the abrasive compound which constitutes the grinder and of minute glass 
particles. 
In these conditions, the machine is thus subjected to very heavy wear, 
which is increased by the fact that the sliding blocks are moved 
continuously, since with the structure according to the known art the 
sliding block is necessarily arranged in its lowered position along the 
portion during which it retains the plate but is lifted in the opposite 
portions, so that the movement is continuous and wear is very heavy. 
Furthermore, cam systems are used in order to perform the translatory 
motion of the sliding block; such systems do not allow to move the 
conveyors in the opposite direction, as is instead required for 
maintenance or for special events, since the rollers which must follow the 
cams would remain in raised position during the reversal step and would 
consequently interfere with the cams, creating unavoidable breakages. 
SUMMARY OF THE INVENTION 
The aim of the invention is indeed to eliminate the above described 
disadvantages by providing a machine for machining edges, particularly of 
glass plates, wherein the sliding block is always kept at a constant 
height with respect to the machining surface and only a small and very 
thin grip part which can slide with respect to the guides which are 
sealingly protected with respect to the outside, is moved. 
Within the scope of the above aim, a particular object of the invention is 
also to allow even very sharp chamfering angles with no interference of 
the machining heads, since the part which retains the plates is small and 
has an extremely reduced thickness, so that interference is always 
avoided. 
Another object of the present invention is to provide a machine for 
machining the edges of glass plates wherein it is possible to guide the 
translatory motion of the part which is arranged so as to extend the 
sliding block even during the steps of the reversal of the motion of the 
conveyor, without having problems of damage or interference. 
Not least object of the present invention is to provide a machine for 
machining edges, particularly of glass plates, which by virtue of its 
peculiar characteristics of execution is capable of giving the greatest 
assurances of reliability and safety in use. 
This aim, these objects, and other aims and objects which will become 
apparent hereinafter, are achieved by a machine for machining edges, 
particularly of glass plates, according to the present invention, as 
defined in the appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
With reference to the above figures, the machine for machining edges, 
particularly of glass plates, comprises a supporting structure, generally 
indicated by the reference numeral 1 in FIG. 7, on which two conveyors 2 
are provided; said conveyors are arranged mutually opposite so as to 
retain, between them, a glass plate arranged edgeways. 
The conveyors extend continuously, and each has an arm 2a which is arranged 
adjacent so as to engage the plates. 
At least one of the conveyors 2, as seen in FIGS. 7-9, is constituted by a 
plurality of sliding blocks, generally indicated by the reference numeral 
10, each of which comprises a supporting body 11 which is provided, in a 
rearward position, with couplings, generally indicated by 12, for the 
connection of the various adjacent sliding blocks so as to define in 
practice a pair of chains 13 which extends continuously. 
It should be noted that since the FIGS. 7-9 show only one conveyor belt, 
another supporting means for the glass plate is arranged mutually opposite 
to the plate engaging arm 2a as seen in FIG. 7, so that as mentioned 
previously such arm 2a and supporting means engage the glass plate which 
is arranged edgeways, that is vertically into the plane of FIG. 7 (FIG. 7 
being a plan view). The oppositely arranged supporting means can be 
completely similar to the conveyor belt as seen in FIGS. 7-9, or 
alternatively it can be a conventional roller belt or even a fixed 
support. The grinding tool for machining the edge of the glass plate is 
fixed in a position below the conveyor belt of FIG. 7 in a conventional 
manner, in order to thereby machine a lower edge of such plate. 
A covering, indicated by 20, is provided on the supporting body 11, is 
advantageously made of rubber or similar materials and is connected by 
means of lugs 21 which are inserted in holes 22 defined o the supporting 
body. 
The covering 20 defines, on its active face, a plurality of blocks 23 which 
engage the plate by contact. 
An important feature of the invention is constituted by the fact that the 
supporting body 11, in the region which is contained by the covering 20, 
defines a T-shaped seat 25 which constitutes means for the retention and 
sliding guiding of a rod-like element 26 which has connected to its own 
lower end a pad 27; said pad is possibly covered with soft material, has a 
reduced thickness, and its active face is substantially flush with the 
ends of the plurality of blocks 23. 
The covering 20 has the peculiar function of constituting a sealing element 
which prevents the infiltration of abrasive material in the T-shaped seat, 
consequently avoiding wear. 
For this purpose, the covering 20 is provided, in a downward position, with 
an opening 30 from which the pad 27 protrudes. Said opening 30 is 
delimited downward by an elastic lip 31 which rests above the element 26 
so as to constitute a seal, and is similarly provided, on the opposite 
edge, with an elastic flap 32 which prevents the passage of abrasive 
material or dirt toward the region affected by the guides. 
With the described arrangement, the sliding block thus always maintains its 
working level, whereas it is the pad 27 that is vertically adjustable with 
respect to the working surface, so as to be able to engage small glass 
plates. 
This fact is very important, since the regions subjected to mutual sliding, 
i.e. the rod-like element 26 which slides in the guide 25, are not 
subjected to particular wear. 
To the above one should furthermore add that a roller 40 is provided at the 
upper end of the element 26 and has the function of engaging means for 
vertically positioning the pads. 
Said means, as more clearly illustrated in FIGS. 7 to 9, are constituted by 
a pair of box-like open-ended elements, indicated by 41 and 42, which are 
arranged one after the other and respectively define a lower edge 41a, 42a 
and an upper edge 41b and 42b, which mutually converge in the central 
region, i.e., if the two box-like elements are seen one after the other, 
they respectively have a converging arrangement and a diverging 
arrangement. The open-ended box-like elements are arranged so that the 
rollers 40 of the elements 26 pass through such box-like elements when the 
blocks 10 are set in motion. 
Said box-like elements 41 and 42 are articulated at their outward-ends the 
supporting structure, so as to allow the vertical movement of the central 
ends, with the consequent shift of the position of the lower and upper 
tracks defined thereby. 
More in detail, the positioning level of the pads is determined by the 
vertical positioning of the central ends of the box-like elements, 
independently of the level assumed by the pads when the related rollers 
enter the region delimited by the box-like elements. 
In fact, if the rollers are arranged higher than the central ends, they 
engage the upper tracks and are lowered to the required level, whereas if 
the rollers are arranged lower than the central ends, they engage the 
lower track, consequently raising the pads. Thus it is seen that in effect 
the tracks of the box-like elements 41 and 42 function as cams upon which 
the rollers 40 follow during movement of the sliding blocks 10 to thereby 
determine the vertical position of the rod-like elements 26 and 
corresponding pads 27. The pads 27 are advantageously lowered, when 
needed, in order to engage a glass plate which does not have a vertical 
extension large enough to been gaged by the blocks 23. 
If the rollers enter the box-like elements already at the correct height, 
the rod-like elements in practice undergo no translatory motions. 
The use of two box-like elements arranged after one another allows to 
reverse the sliding motion of the conveyors without thereby causing 
problems. 
In order to vary the height of the central ends of the box-like elements 
there is a unit for adjusting the means for vertically positioning the 
pads, illustrated in figure 10, which in a simplified form is constituted 
by a fixed vertical threaded rod 50 on which a first bevel gear 51 is 
screwed; the first head gear meshes with a second bevel gear 52 which is 
connected to a handwheel 53, which is rotatably supported by a movable 
carriage 54, which is connected to the first bevel gear 51 as seen in FIG. 
10, and which, by means of pins or the like, connects to slots 56 defined 
on the ends of the box-like elements. 
The translatory motion of the carriage and of the central ends of the 
box-like elements connected thereto is consequently caused by acting on 
the handwheel. 
From what has been described above it can thus be seen that the invention 
achieves the intended aim and objects, and in particular the fact is 
stressed that the solution consisting in keeping at a fixed height the 
sliding blocks which engage the glass plates, moving only a pad which is 
connected to a plate-like element which can slide in guides which are 
arranged inside the sliding blocks and are protected outward, allows to 
eliminate the severe wear problems which are observed in these machines, 
also taking into account the fact that the area where they operate is 
subjected to the diffusion of abrasive material. 
The provision of the means for positioning the pads by virtue of a pair of 
box-like elements arranged after one another and having tracks which 
converge toward their central ends allows to reverse the movement of the 
traction elements, as cannot be obtained on known machines. 
The invention thus conceived is susceptible to numerous modifications and 
variations, all of which are within the scope of the invention concept. 
All the details may furthermore be replaced with other technically 
equivalent elements.