DIGITALLY CONTROLLED GRINDER, PARTICULARLY FOR GLASS SHEETS WITH STRAIGHT SIDES

Abstract

Digitally controlled grinder, particularly for glass sheets with straight sides, comprising at least one first conveyance guide which defines a loading surface for at least one glass sheet to be ground and is adapted to convey it into a grinding station, which defines a grinding surface that is adjacent to the loading surface, with the glass sheet to be ground resting, on the loading surface, measurement elements being further comprised, combined rotary and translational motion elements adapted for the combined rotary and translational motion of the loading surface with respect to the grinding surface, and processing and control elements which are functionally connected both to the measurement elements and to the combined rotary and translational motion elements and are adapted to actuate the latter elements as a function of the measurements made by the measurement elements and of the final geometry to be obtained of the glass sheet.

Description

TECHNICAL FIELD

The present invention relates to a digitally controlled grinder, particularly for glass sheets with straight sides.

BACKGROUND ART

Nowadays, conventional grinders used for working glass, are based on the principle of placing a glass sheet to be ground with straight sides on a conveyor belt, in an adapted loading station, conveying the glass sheet to be ground into a grinding station in which a plurality of tools, mutually aligned on a grinding surface, perform the grinding of the glass sheet one side at a time.

In more detail, once the optimal surface of the tools is defined, the quantity of material to be removed from the rough glass sheet can, in some cases, be defined by adjusting the height of the loading surface with respect to the grinding surface.

Such conventional grinders are not devoid of drawbacks among which is the fact that the glass sheet on exit from the grinding station can only have the same shape that the glass sheet had on entry to the grinding station.

In fact, since the loading surface can only be lowered with respect to the grinding surface by an amount equal to the quantity of material to be removed, the final geometry of the glass sheet will have the same angles of the corners as the geometry of the glass sheet had on entry to the grinding station.

For example, if on entry the glass sheet has a rhomboid shape, then on exit it will have the same shape, reduced only by the removal of the material worked by the tools. A square glass sheet can come out squared, i.e., with the angles of the corners between adjacent sides equal to 90°, only if it already had the corners squared at 90° when it was rough.

DISCLOSURE OF THE INVENTION

The aim of the present invention is to provide a digitally controlled grinder, particularly for glass sheets with straight sides, that solves and overcomes, respectively, the drawbacks and the limitations of the known art.

Within this aim an object of the present invention is to provide a grinder that makes it possible to obtain a glass sheet with angles of the corners between adjacent sides and dimensions of any value irrespective of the value of the initial angles of the corners and of the initial dimensions.

Another object of the present invention is to provide a grinder that is economically competitive with respect to those of the known art.

This aim and these and other objects which will become better apparent hereinafter, are achieved by a digitally controlled grinder, particularly for glass sheets with straight sides, comprising at least one first conveyance guide, which defines a loading surface for at least one glass sheet to be ground, adapted to convey said glass sheet to be ground into a grinding station with said glass sheet to be ground resting, at one of its sides to be ground, on said loading surface, said grinding station defining a grinding surface which is adjacent to said loading surface, characterized in that it comprises measurement means which are adapted to measure either or both of the shape and the dimensions of said glass sheet to be ground arranged on said loading surface, combined rotary and translational motion means adapted for the combined rotary and translational motion of said loading surface with respect to said grinding surface for the combined rotary and translational motion of said glass sheet to be ground with respect to said grinding surface, and processing and control means, which are functionally connected to said measurement means and to said combined rotary and translational motion means and are adapted to actuate said combined rotary and translational motion means as a function of the measurements made by said measurement means and of the final geometry to be obtained of said glass sheet.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will become better apparent from the detailed description of a preferred, but not exclusive, embodiment of a digitally controlled grinder, particularly for glass sheets with straight sides, which is illustrated by way of non-limiting example in the accompanying drawings, wherein:

FIG. 1 is a schematic side elevation view of a digitally controlled grinder, particularly for glass sheets with straight sides, according to the invention;

FIGS. 2 and 3 are two schematic side elevation views of the grinder shown in FIG. 1, during its operation.

WAYS OF CARRYING OUT THE INVENTION

With reference to the figures, the digitally controlled grinder, particularly for glass sheets with straight sides, generally designated by the reference numeral 1, according to the invention, comprises a supporting structure that can be arranged on a resting surface 2 and is constituted by a bed and a frame 4 which is made from a plurality of posts 5 and cross-members 6 which are arranged on a plane that is substantially inclined with respect to the vertical direction.

In more detail, the grinder 1 is subdivided into a loading station 7a, followed by a grinding station 7b, followed in turn by an unloading station 7c.

The loading station 7a comprises at least one first conveyance guide 8 which defines a loading surface 9 onto which at least one glass sheet 10 to be ground is loaded.

This first conveyance guide 8 is adapted to convey the glass sheet 10 to be ground into the grinding station 7b with the glass sheet 10 to be ground resting, at one of its sides to be ground 10a, on the loading surface 9.

For example, the first conveyance guide 8 can be provided by a straight element having a central groove, the base of which defines the loading surface 9 and in which the glass sheet 10 to be ground is inserted.

In more detail, the glass sheet 10 is placed so that it can slide laterally on the cross-members 6 of the frame 4, which are provided with adapted idle rollers 12 that are adapted to allow the sliding of the glass sheet 10 with respect to the frame 4.

In this way, by way of entrainment means, not shown and consisting, for example, of one of a plurality of pairs of motorized rollers arranged laterally to the groove of the first conveyance guide 8 which grip the glass sheet 10, it is possible to make the glass sheet 10 slide from the loading station 7a to the grinding station 7b.

The grinding station 7b comprises a plurality of grinding wheels 13 that are mutually adjacent and define at least one grinding surface 14 that is adjacent to the loading surface 9.

More precisely, the grinding wheels 13 can be provided with different tools so as to enable both chipping operations, with the glass sheet 10 passing over the first grinding wheels 13 present in the grinding station 7b, and finishing operations, with the glass sheet 10 passing over the last grinding wheels 13 present in the grinding station 7b.

The movement of the glass sheet 10 along the grinding surface 14 comes about by means of at least one second conveyance guide 15 which can be provided by a pair of straight elements provided with motorized rollers adapted to entrain the glass sheet 10 as occurs in the loading station 7a. In this case however, the groove is a through groove and ends with the grinding surface 14 defined by the grinding wheels 13.

Finally, the unloading station 7c comprises at least one third conveyance guide 16 which defines an unloading surface 17 on which the glass sheet 10 is unloaded once the work is done, i.e., once it has been ground in the grinding station 7b.

The third conveyance guide 16 can be of the same type as the first conveyance guide 8 and the unloading surface 17 is adjacent to the grinding surface 14 on the opposite side with respect to the loading surface 9.

According to the invention, measurement means 18 are provided which are adapted to measure either or both the shape and the dimensions of the glass sheet 10 to be ground arranged on the loading surface 9, combined rotary and translational motion means 19 adapted for the combined rotary and translational motion of the loading surface 9 with respect to the grinding surface 14 for the combined rotary and translational motion of the glass sheet 10 to be ground with respect to the grinding surface 14, and processing and control means 20 which are functionally connected both to the measurement means 18 and to the combined rotary and translational motion means 19 and are adapted to actuate the latter means as a function of the measurements made by the measurement means 18 and of the final geometry to be obtained of the glass sheet 10.

In more detail, the measurement means 18 can consist of at least two photocells 21, which are arranged in a preset position with respect to the grinding surface 14 and are adapted to detect the passage of the glass sheet 10 to be ground on the loading surface 9 at a side 10b thereof that is adjacent to the side 10a to be ground in order to determine, by way of the processing and control means 20, the angle comprised between the adjacent side 10b and the side 10a to be ground.

Alternatively, as a function of the measurements of shape and dimensions for which the measurement means 18 are provided, such means can comprise, in addition to the photocells 21 shown or as an alternative to them, other types of sensor such as, for example, linear encoders or the like.

Advantageously, the processing and control means 20 comprise at least one user interface 22 provided, for example, by a computer and adapted for the entry by an operator of control data that define the final geometry of the glass sheet 10.

The combined rotary and translational motion means 19 comprise at least two actuators 24 and 25 which are associated with the first conveyance guide 8, for example, at its end portions and are adapted to move it with respect to the grinding surface 14.

As will be better described hereinafter, the two actuators 24 and 25 are functionally connected to the processing and control means 20 and can be actuated independently of each other in order to enable both rotations and translational movements of the loading surface 9.

Operation of the digitally controlled grinder 1, particularly for glass sheets with straight sides, is described hereinafter.

In the grinding process, the first side 10b to be worked on is arranged on the entry conveyor and is processed.

Subsequently, the glass sheet 10 is returned to the loading surface 9 with the side 10a to be ground adjacent to the side 10b, which was ground previously, in such a way that the latter is arranged on the entry conveyor for the processing of the side 10a to be ground.

As shown in FIG. 1, the angle comprised between the side 10a to be ground and the adjacent side 10b will be unchanged with respect to the initial geometry, and the adjacent side 10b will diverge from the normal to the grinding surface 14 by an angle “α”, which is measured by the two photocells 21 during the passage of the glass sheet 10 to be ground on the loading surface 9.

As shown in FIG. 2, once the angle “α” is measured, the first conveyance guide 8, provided with the two actuators 24 and 25, is made to rotate through an angle “β” which is such as to compensate for the inclination measured previously, and carry the side 10b inclined with respect to the grinding surface 14 at an angle equal to that of the desired final geometry.

In the figures, for the purposes of example, the desired final geometry is to have the sides 10a and 10b square with respect to each other, i.e., defining a right angle.

At this point the conveyor advances but, in order to allow the correct entry of the glass sheet 10 into the grinding station 7b, the loading surface 9 no longer being in line with the grinding surface 14, the first conveyance guide 8 advances the glass sheet 10 and at the same time is raised or lowered, interpolating this movement with the advancement of the glass sheet 10, depending on the angle of inclination, positive or negative, so as to accompany, during transport for grinding, the glass sheet 10 in line with the grinding surface 14, as shown in FIG. 3.

Proceeding in this way, for all the remaining sides which, since this is the processing of polygonal glass sheets, can be three or more in number, a sheet of glass 10 is thus obtained with the desired geometry of the angles of the corners which can be squared or intentionally off-square according to the desired specifications.

Conveniently, if it is necessary to make a glass sheet 10 perfectly squared, the processing and control means 20 can be implemented so as to not require the operator to enter any control data.

Differently, if a final geometry is desired which defines angles of the corners that are not squared, it will be necessary to enter control data in order to obtain a glass sheet 10 with the desired final geometry.

Moreover, by entering adapted dimension data into the processing and control means 20, the grinder 1 is capable of defining the final dimensions of the glass sheet 10, and not only the geometry of the angles of its corners.

In more detail, this can come about by means of entering the final geometry (the angles of the corners and the lengths of the sides) into the processing and control means 20 and the measurement of the length of each worked side of the glass sheet 10 by way of the measurement means 18.

During working of the first side 10b the grinder 1 measures its length and during working of the subsequent sides the grinder 1 measures each of their lengths in order to then arrive at the final size of the glass sheet 10 by managing the removal of material by means of adjusting the height and orientation of the loading surface 9 with respect to the grinding surface 14 based on the necessary trigonometric calculations performed by the processing and control means 20, thus obtaining a worked glass sheet 10 of the desired shape and dimensions.

In practice, it has been found that the digitally controlled grinder, particularly for glass sheets with straight sides, according to the present invention, fully achieves the intended aim and objects since it makes it possible to obtain glass sheets with angles of the corners and dimensions of any value irrespective of the value of the initial angles of the corners and of the initial dimensions.

Another advantage of the grinder, according to the present invention, consists in that it is, from the point of view of investment, economically competitive with respect to those of the known art and, from the point of view of processing costs, economically advantageous with respect to those of the known art since it makes it possible to do away with all the measurement operations carried out outside the machine which, in machines of the known type, are done manually by the operator.

The digitally controlled grinder, particularly for glass sheets with straight sides, thus conceived, is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

Moreover, all the details may be substituted by other, technically equivalent elements.

In practice the materials employed, provided they are compatible with the specific use, and the contingent dimensions and shapes, may be any according to requirements and to the state of the art.

The disclosures in Italian Patent Application No. MI2010A001669 from which this application claims priority are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1-7. (canceled)

8. A digitally controlled grinder, particularly for glass sheets with straight sides, comprising at least one first conveyance guide, which defines a loading surface for at least one glass sheet to be ground, adapted to convey said glass sheet to be ground into a grinding station with said glass sheet to be ground resting, at one of its sides to be ground, on said loading surface, said grinding station defining a grinding surface which is adjacent to said loading surface, further comprising measurement means which are adapted to measure either or both of the shape and the dimensions of said glass sheet to be ground arranged on said loading surface, combined rotary and translational motion means adapted for the combined rotary and translational motion of said loading surface with respect to said grinding surface for the combined rotary and translational motion of said glass sheet to be ground with respect to said grinding surface, and processing and control means, which are functionally connected to said measurement means and to said combined rotary and translational motion means and are adapted to actuate said combined rotary and translational motion means as a function of the measurements made by said measurement means and of a final geometry to be obtained of said glass sheet.

9. The grinder according to claim 8, further comprising at least one second conveyance guide defined at said grinding surface.

10. The grinder according to claim 9, further comprising at least one third conveyance guide, which defines a surface for unloading said glass sheet ground in said grinding station, said unloading surface being adjacent to said grinding surface on the opposite side with respect to said loading surface.

11. The grinder according to claim 8, wherein said grinding surface is defined by a plurality of grinding wheels, which are accommodated in said grinding station and are mutually adjacent.

12. The grinder according to claim 8, wherein said combined rotary and translational motion means comprise at least two actuators, which are associated with said at least one first conveyance guide and are adapted to move it with respect to said grinding surface, said at least two actuators being functionally connected to said processing and control means and being actuatable independently of each other.

13. The grinder according to claim 8, wherein said processing and control means comprise at least one user interface, which is adapted for entry, by an operator, of control data that define the final geometry of said glass sheet.

14. The grinder according to claim 8, wherein said measurement means comprise at least two photocells, which are arranged in a preset position with respect to said grinding surface and are adapted to detect the passage of said glass sheet to be ground on said loading surface at a side thereof that is adjacent to said side to be ground in order to determine, by way of said processing and control means, an angle comprised between said adjacent side and said side to be ground.