Machine for removing the sharp edge in plates in general and in particular in glass plates

Abstract

A machine for removing sharp edge in plates in general and in glass plates in particular, comprising a frame for the support and advancement of a plate on which there is at least one station for arrissing an edge of the plate, the arrissing station comprising an upper tangential grinding wheel and a lower tangential grinding wheel which have a working profile which is inclined at 45° with respect to the rotation axis of the grinding wheels and can engage respectively an upper edge and a lower edge of the plate being worked.

Description

The present invention relates to a machine for removing the sharp edge in plates in general and in glass plates in particular.

BACKGROUND OF THE INVENTION

As is known, in the case of plates which are subject to cutting, sharp edges are formed which can be dangerous and consequently must be removed.

Considering, merely by way of example, the case of glass plates, machines commonly known as arrissing machines are currently commercially available which are designed to remove part of the edge, thus eliminating the sharp arris.

Such removal operations are performed typically by means of diamond belts which engage the arrises of the plate at a 45° angle with respect to the plane of the glass pane and move substantially at right angles to the advancement of the plate.

Other known solutions use peripheral grinding wheels having a V-shaped transverse cross-section, which allows to perform arrissing simultaneously on both arrises of the edge.

Another known solution uses cup grinding wheels which work frontally and engage the arrises of the edge of the plate with an inclination of substantially 45° with respect to the plane of the glass pane.

Generally, known solutions produce an irregular removal of the sharpness of the arris along the entire length, a defect particularly observable in systems with a grinding wheel which is in a fixed position with respect to the glass pane, since the sharp edge of the plate has a linearity error caused by the preceding cutting operation and most of all there is a mismatch between the upper sharp edge and the lower sharp edge caused by the typical irregularity of glass plate cutting operations.

Another problem encountered with the solutions of the background art is due to irregular removal at the end of the sharp edges, due to incorrect positioning, during the initial step, of the abrasive element with respect to the plate.

Moreover, known solutions suffer additional problems in case of a plate thickness change, since only the abrasive belt is capable of adapting, within a certain interval, to the thickness variation.

Another problem further consists in that the grinding wheels that are used undergo localized wear, which creates considerable machining variations, and therefore it is necessary to perform adjustments frequently.

SUMMARY OF THE INVENTION

The aim of the invention is to solve the problems described above by providing a machine for removing the sharp edge in plates in general and in glass plates in particular, which allows to provide uniform and homogeneous removal of the sharp edge on all arrises, thus obtaining a significant increase in machining quality.

Within this aim, an object of the invention is to provide a machine which allows to increase considerably the machining speed while solving the problem of uneven wear of the grinding wheels that are used.

Another object of the present invention is to provide a machine which, thanks to its particular constructive characteristics, is capable of giving the greatest assurances of reliability and safety in use.

Still another object of the present invention is to provide a machine for removing the sharp edge in plates in general and in glass plates in particular which can be obtained easily starting from commonly commercially available elements and materials and is also competitive from a merely economical standpoint.

This aim and these and other objects, which will become better apparent hereinafter, are achieved by a machine for removing the sharp edge in plates in general and in glass plates in particular, according to the invention, comprising a frame for the support and advancement of a plate on which there is at least one station for arrissing an edge of said plate, characterized in that said arrissing station comprises an upper tangential grinding wheel and a lower tangential grinding wheel, which have a working profile which is inclined with respect to the axis of rotation of the grinding wheel and can engage respectively the upper edge and the lower edge of said plate.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will become better apparent from the description of a preferred but not exclusive embodiment of a machine for removing the sharp edge in plates in general and in glass plates in particular, illustrated by way of non-limiting example in the accompanying drawings, wherein:

FIG. 1 is a schematic perspective view of the arrissing station for the edge of a plate with the main motor and the belt removed;

FIG. 2 is a schematic perspective view of the mutual arrangement of the tangential grinding wheels and of the plate;

FIG. 3 is a front elevation view, of the tangential grinding wheels in the plate advancement direction;

FIG. 4 is a front view of the machine for removing the sharp edge;

FIG. 5 is a sectional view, taken along the line V-V of FIG. 4;

FIG. 6 is a sectional view, taken along the line VI-VI of FIG. 4;

FIG. 7 is a schematic perspective view, taken from the outer side, of the cantilever assembly which supports the corresponding tangential grinding wheel;

FIG. 8 is a top-up plan view of the cantilever assembly;

FIG. 9 is a perspective view, taken from the outer side, of the arrissing station with the motor means highlighted;

FIG. 10 is a schematic view of the arrissing station taken from the inner side, i.e., directed toward the plate advancement belt;

FIG. 11 is a top plan view of the arrissing station.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the figures, the machine for removing the sharp edge in plates in general and in glass plates in particular, generally designated by the reference numeral 1, comprises a frame 2 for the support and advancement of a plate 3 which is rested for example on a belt 4 which unwinds continuously.

At least one and preferably a plurality of arrissing stations, generally designated by the reference numeral 10, are typically provided at the edges of the plate.

Arrissing stations are usually provided on both of the advancement sides of the plate, which has a rectangular shape, and moreover the line provides for two machines with an interposed 90° transfer system, so that all the four edges of the plate are machined.

The drawing illustrates a single arrissing station, but of course, as mentioned earlier, the stations are typically four in number.

Each arrissing station 10 comprises an upper tangential grinding wheel 11 and a lower tangential grinding wheel 12.

The grinding wheels have a machining or working profile 11a and 12a which is inclined at 45° with respect to the axis of rotation.

Each grinding wheel can engage respectively the upper edge and the lower edge of the plate 3 being machined.

The grinding wheels 11 and 12 are supported by respective spindles, both designated by the reference numeral 15, which are connected by means of a cantilever support 16 with a vertical central shaft 17 which is supported by means of eyes 18 which are connected to the fixed structure.

The shaft 17 has an upper pulley 19 which by means of a belt 20 draws motion from a driving pulley 21 which is connected to a main motor 22.

Each cantilever support can oscillate about the central axis 17 and is pushed to machine by means of a pusher, which is advantageously provided by means of a pneumatic cylinder 30, the piston 30a whereof acts by pushing on the cantilever element so as to render active the sharp edge of the corresponding grinding wheel.

Each cantilever element supports, rigidly associated with the shaft of the corresponding grinding wheel, an upper grinding wheel pulley 31 and a lower grinding wheel pulley 32 on which an upper grinding wheel belt 34 and a lower grinding wheel belt 35 respectively unwind, said belts winding around respective upper and lower central pulleys 36 and 37 which are keyed on the central shaft 17 which draws motion from the motor 22.

With this type of connection, the grinding wheels are turned about their own axis and the cantilever element is structured so as to move the inclined edges of the corresponding grinding wheels 11 and 12 so that they work the upper and lower arrises of the plate 3.

To allow uniform wear of the grinding wheel, there is provided a system for oscillating along a vertical direction, which comprises an oscillation motor 40 which is connected, for example by means of a nut screw coupling 41, to the panel 42 which can slide with respect to the frame and supports the cantilever elements, imparting thereto a reciprocating translational motion along the vertical axis, so that the point of the inclined working profile of the grinding wheels is changed in each instance.

With this arrangement, only the cantilever elements with the corresponding spindles are moved, and, for this purpose the pulleys 36 and 37 have an increased axial extension with respect to the width of the corresponding belt, so as to adapt to the variation in the placement of the pulleys 31 and 32 connected to the spindles 15.

This type of connection allows to have reduced moving masses, since the motors, due to the rotation of the grinding wheel and to the oscillation along the vertical direction, remain in a fixed position.

To allow correct placement of the grinding wheels with respect to the edge of the plate, especially in the initial step, positioning cams are provided which are constituted by an upper cam and by a lower cam, both designated by the reference numeral 50, which engage an abutment roller 51, which is associated with the respective cantilever element, so as to provide an element for stopping the advancement of the grinding wheel toward the plate, therefore providing exact positioning even in the initial step of the engagement between the grinding wheel and the plate.

It should be added that the cam 50 arranged in an upper region can be connected to a vertical positioning device, which is provided for example by a piston 60 which changes the relative position of the cam 50 arranged above according to the thickness of the plate.

With the apparatus described above, the plate to be worked is engaged by the conveyor belt 4 and, during its advancement, encounters the arrissing stations, usually provided one for each side.

The lower spindle, with its grinding wheel turning, interferes with the plate to an extent which is preset by the contact of the cantilever system which is adjusted by the arrangement of the cam 50.

Contact with the plate causes the movement of the spindle to the balancing point between the grinding force and the force of the pneumatic cylinder that pushes the cantilever element so that the lower arris of the edge is machined.

The plate, in its advancement, then encounters the upper spindle, which machines the upper sharp edge in the same manner described above.

When the plate abandons the spindles, the cantilever element moves the cam so that it abuts against the abutment roller and is positioned for subsequent work.

During the working step, the spindles are made to oscillate in a vertical direction so that contact between the grinding wheel and the plate occurs by utilizing the entire band, having a conical profile, of the tangential grinding wheel, so that uniform wear is obtained, minimizing the need for replacement or redressing of the grinding wheel.

From what has been described above it is evident that the invention achieves the intended aim and objects, and in particular the fact is stressed that a machine is provided in which the sharp edge of the plate is arrissed by using two distinct tangential grinding wheels with a 45° contour, achieving uniform work thanks to the fact that such grinding wheels are supported by respective cantilever elements which allow to adapt the mutual positioning between the grinding wheel and the plate.

Another important aspect of the invention consists in that the control motors of the grinding wheels and of the vertical oscillation do not affect the moving masses, which are constituted exclusively by the cantilever elements which are thus positioned correctly with respect to the edge being worked thanks to the presence of the cam elements and of the constant thrust applied by the pneumatic pistons which keep the grinding wheels in working contact against the edge.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

All the details may further be replaced with other technically equivalent elements.

In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to requirements.

The disclosures in Italian Patent Application No. MI2006A001986 from which this application claims priority are incorporated herein by reference.

Claims

1. A machine for removing sharp edge in plates in general and in glass plates in particular, comprising a frame for the support and advancement of a plate on which there is at least one station for arrissing an edge of said plate, wherein said arrissing station comprises an upper tangential grinding wheel and a lower tangential grinding wheel which have a working profile which is inclined with respect to a rotation axis of the grinding wheels and can engage respectively an upper edge and a lower edge of said plate.

2. The machine according to claim 1, wherein said grinding wheels have a working profile which is substantially inclined at 45° with respect to the axis of rotation of the grinding wheels.

3. The machine according to claim 1, wherein said grinding wheels are supported so that they can rotate by spindles which are connected by means of a cantilever support with a vertical central shaft.

4. The machine according to claim 3, wherein said cantilever supports are connected to said vertical central shaft with the possibility to oscillate about said vertical central shaft.

5. The machine according to claim 3, further comprising means for turning said vertical central shaft which is functionally associated with said spindles.

6. The machine according to claim 6, wherein said means for turning said vertical central shaft comprise an upper pulley, which is keyed to said shaft and is functionally connected to a belt which engages a driving pulley, which is connected to a main motor which is rigidly coupled to said support and advancement frame.

7. The machine according to claim 3, further comprising, for each of said cantilever supports, a pusher which is adapted to push said tangential grinding wheels against the edge of the plate being worked.

8. The machine according to claim 7, wherein said pusher is constituted by a pneumatic cylinder whose piston acts by pushing on said cantilever element.

9. The machine according to claim 3, wherein each of said cantilever elements supports rotatably a shaft of the corresponding grinding wheel on which an upper grinding wheel pulley and a lower grinding wheel pulley are keyed respectively, said pulleys being connected respectively, by means of an upper grinding wheel belt and a lower grinding wheel belt, to a central upper pulley and a central lower pulley, which are keyed on said central and vertical shaft.

10. The machine according to claim 3, further comprising means for the oscillation of said cantilever elements along a substantially vertical direction.

11. The machine according to claim 10, wherein said oscillation means comprise an oscillation motor, which is supported by said frame and can be coupled by means of a nut screw coupling to a panel which supports said cantilever elements.

12. The machine according to claim 9, wherein said upper central and lower central pulleys have a greater axial extension than said upper and lower grinding wheel belts in order to compensate the oscillating motion along said vertical direction.

13. The machine according to claim 1, further comprising means for positioning the grinding wheels with respect to the edge of said plate with said grinding wheels disengaged from said edge.

14. The machine according to claim 13, wherein said grinding wheel positioning means comprise positioning cams which are constituted by an upper cam and a lower cam, which can be engaged by respective abutment rollers which are associated with the respective cantilever element.

15. The machine according to claim 14, further comprising means for positioning vertically said upper cam for adaptation to the thickness of the plate.