METHOD AND APPARATUS FOR HOLDING AND PERFORMING WORK ON A SHEET

Abstract

Method for holding and performing work on a sheet is provided. Sheet has a first lateral surface, an opposing second lateral surface and a perimeter edge. The method includes: a step of holding the sheet, a step of working the perimeter edge and also a coordinated step of moving the sheet and/or a step of moving the work head.

Claims

1. A method for holding and performing work on a sheet that has a first and a second opposing lateral surface and a perimeter edge, said method comprising: holding, by a first and a second gripping members, said sheet in a sliding manner, contacting it in at least two respective contact zones of said first and second lateral surface, working, by a work tool, said perimeter edge, wherein working said perimeter edge further comprises: moving said sheet to advance or retract with respect to said work tool in a direction of advance, and moving a work head, on which there are installed at least a work tool and a stabilizing device having said opposing and facing first and second gripping members (11, 12), said work tool being moved along a work axis, and wherein when said work tool performs the work in proximity to or in correspondence with a corner of said perimeter edge, said method further comprising: angularly orienting said work head, and with it said stabilizing device, by an angle of orientation in a manner that is coordinated with said step of moving said sheet and/or said work head, in order to maintain said contact zones within said first and second lateral surface.

2. The method of claim 1, wherein said work head, and with it said stabilizing device, is angularly oriented by an angle of orientation in a manner that is coordinated with said step of moving said sheet and said work head, in order to maintain said contact zones on a bisector of an angle comprised between the sides adjacent to said corner.

3. The method of claim 2, wherein while said corner is being worked, said angle of orientation is a function of said angle.

4. The method of claim 1, wherein while said corner is being worked, said angle of orientation is also a function of the position of said sheet in said direction of advance and of the position of said work head along said work axis.

5. The method of claim 1, wherein said working occurs without interruptions or discontinuities.

6. The method of claim 2, wherein said angle is smaller than 90.

7. The method of claim 1, wherein said corner is sharp or rounded.

8. An apparatus for working sheets comprising: movement means configured to move at least one sheet in a direction of advance, at least one work unit comprising a work head on which at least a work tool and a stabilizing device are installed, said stabilizing device having opposing and facing first and second gripping members, wherein said work head is both linearly mobile and also selectively rotatable, and with it said stabilizing device, according to an angle of orientation, which comprises a central control unit configured to execute a specific work program which contains the scripts to manage at least said movement means and said work head in a coordinated manner, so that said apparatus executes the method as in any claim hereinbefore.

9. The apparatus of claim 8, wherein said gripping members are disposed at a fixed radial distance from said work tool.

10. The apparatus of claim 8, wherein said gripping members are disposed at an adjustable radial distance from said work tool.

11. The apparatus of claim 8, wherein said central control unit is configured to receive at input all the geometric data able to define the shape and sizes of said sheet, including an initial position of said sheet in said direction of advance.

12. The apparatus of claim 9, wherein said central control unit is configured to receive at input the value of said distance.

Description

DESCRIPTION OF THE DRAWINGS

[0039] These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of an embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

[0040] FIG. 1 is a schematic view of an apparatus for working sheets according to the present invention;

[0041] FIG. 2 is a schematic view of the sheet held between the gripping members;

[0042] FIGS. 3-8 show a schematic operating sequence of the working of a corner of the sheet in accordance with the method according to the present invention.

[0043] We must clarify that in the present description the phraseology and terminology used, as well as the figures in the attached drawings also as described, have the sole function of better illustrating and explaining the present invention, their function being to provide a non-limiting example of the invention itself, since the scope of protection is defined by the claims.

[0044] To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications.

DESCRIPTION OF AN EMBODIMENT OF THE PRESENT INVENTION

[0045] With reference to FIG. 1, this shows an apparatus 100 according to the present invention, configured to carry out material removal work on sheets 200 made of glass, or more generally of a fragile material with a behavior similar to glass.

[0046] Each sheet 200 has a first lateral or front surface 210, an opposing second lateral or rear surface 211, and a perimeter edge 212 having a known or previously measured thickness T (FIG. 2). The lateral surfaces 210, 211 are essentially flat and can have a rectangular, circular, elliptical, curvilinear, trapezoidal, triangular or polygonal shape, or a combination thereof.

[0047] For example, as can be seen in the attached drawings, in the case of a triangular sheet, the perimeter edge 212 can be defined by a frontal side 212A, an opposing rear side 212B, and a lower side 212C.

[0048] According to some embodiments, the apparatus 100 comprises an inlet section A, in correspondence with which one or more sheets 200 to be worked are supplied to the apparatus 100, and an outlet section B, in correspondence with which the worked sheets 200 are evacuated from the apparatus 100.

[0049] The apparatus 100 comprises a work plane P, shown by way of example in FIG. 1 with a dashed line, which is substantially vertical and on which the sheets 200 rest with respect to one of the two lateral surfaces 210, 211.

[0050] The apparatus 100 comprises a first movement unit 111, for example of the roller type, comprising an inlet conveyor 117 driven by a first motor M1 and an outlet conveyor 118 driven by a second motor M2, and configured to move one or more of the sheets 200 on the work plane P in a direction of advance F, which goes from the inlet section A to the outlet section B, supporting it and dragging it at the lower part.

[0051] The apparatus 100 comprises a second movement unit 112 of the sucker type driven by means of a third motor M3 and configured to hold and move the sheet 200 on the work plane P in the direction of advance F by dragging it laterally, that is, with respect to its first lateral surface 210, that is, the front one, or more advantageously with respect to its second lateral surface 211, that is, the rear one. The first and second movement unit 111, 112 can be activated simultaneously to cooperate in the movement of the same sheet 200, or they can be activated independently.

[0052] The apparatus 100 comprises at least one work unit 113 having a vertical or inclined configuration, substantially parallel to the work plane P and being disposed in correspondence with an intermediate section C which is positioned between the inlet section A and the outlet section B.

[0053] The work unit 113 comprises a work head 123 and a guide 124 which develops along a work axis Y and along which the work head 123 is sliding, the movement of the work head 123 being managed by a fourth motor M4.

[0054] The work unit 113 comprises a work tool 125 associated with the work head 123. The work tool 125 is keyed onto a spindle associated with the work head 123, in a manner known per se, and its rotation (arrow R in FIGS. 3-8) is managed by a fifth motor M5.

[0055] In the embodiment described here, the work tool 125 is a grinding wheel. However, it is not excluded that the work tool 125 is configured to perform other work.

[0056] The work unit 113 also comprises a stabilizing device 10 associated with the work head 123 and configured to hold the sheet 200 in correspondence with its perimeter edge 212 and in proximity to the work tool 125, stabilizing its position in order to avoid vibrations during working.

[0057] With particular reference to FIG. 2, the stabilizing device 10 comprises first gripping members 11 and opposing and facing second gripping members 12.

[0058] The first and second gripping members 11, 12 comprise a respective support element (not shown) which can be for example a jaw, and at least one respective contact element 11b, 12b, which in the present case is a wheel or an idle roller with axis orthogonal to the axis of rotation of the work tool 125.

[0059] The contact elements 11b, 12b are configured to hold the sheet 200 in a sliding manner by contacting it in at least two respective contact zones P1, P2 which lie on the first and second lateral surface 210, 211. In a more general sense, these contact zones P1, P2 can correspond to respective contact areas, with a rectangular or other shape, which are more or less extended according to the degree of deformability which the contact elements 11b, 12b or their coating consist of.

[0060] While the sheet 200 is being held, both contact elements 11b, 12b remain in contact with the sheet 200 in correspondence with the contact zones P1, P2.

[0061] The gripping members 11, 12 are disposed at a distance D from the peripheral surface of the work tool 125 which is fixed, see for example FIG. 3.

[0062] The first and second gripping members 11, 12 are located, during use, respectively on one part and on the other of the sheet 200, and at least one of them is able to be selectively moved along a gripping and release axis, which is orthogonal to the lateral surfaces 210, 211, according to a suitably calibrated relative approach/distancing movement.

[0063] The work head 123, and with it the stabilizing device 10, is able to be orientated according to an angle of orientation by means of a sixth motor M6. The rotation according to the angle of orientation is functional to correctly orient the first and second gripping members 11, 12 with respect to the sheet 200. In fact, since the work tool 125, at least in the case of the grinding wheel, has a cylindrical conformation, its angular orientation around its own axis of rotation would in any case not entail any effective variation in its functionality.

[0064] Particularly if the sheet 200 has a shape with acute vertexes between one side and the next of its perimeter edge 212 and work has to be performed in proximity to the vertex, the possibility of rotating and suitably positioning the first and second gripping members 11, 12 becomes crucial to maintain a firm grip on the sheet 200 and avoid vibrations during working.

[0065] The apparatus 100 comprises a central control unit 116 configured at least to manage the first movement unit 111, the second movement unit 112 and the work unit 113, including the work head 123 with the work tool 125 and the stabilizing device 10 (in its opening-closing movement), in order to guarantee the execution of optimized work on the sheet 200.

[0066] The central control unit 116 is configured to execute a specific work program which contains the scripts for managing at least the forward/reverse motion of the sheet 200, and the linear and angular movement of the work head 123 in a coordinated manner, so that the apparatus 100 executes the work method described below. Favorably, the work program is parameterized on the basis of both physical data relating to the sheet and also physical data relating to the work tool 125.

[0067] Thanks to the work program, for each individual situation (acute, obtuse vertexes of the sheet, etc.) the ideal positioning conditions of the gripping members 11, 12 are identified by rotating the work head 123, and with it the stabilizing device 10, by the angle of orientation .

[0068] The operation of the apparatus 100, which corresponds to the method according to the present invention, comprises the following steps.

[0069] A pre-positioning step which occurs in a manner per se known by detecting the position of at least one side of the perimeter edge 212, in which the sheet 200 is pre-positioned with respect to the work tool 125.

[0070] The pre-positioning step can occur by means of the first movement unit 111, the second movement unit 112 or in a combined manner.

[0071] Immediately after the sheet 200 has reached the correct position relative to the work tool 125, the method comprises a holding step, in which the contact elements 11b, 12b of the first and second gripping members 11, 12 hold the sheet 200 with respect to the two front 210 and rear 211 surfaces.

[0072] The sheet 200 is held in a sliding manner. In other words, when during working it is made to slide forward or backward in the direction of advance F, the sheet 200 can also slide with respect to the contact elements 11b, 12b.

[0073] The contact elements 11b, 12b contact the sheet 200 in correspondence with at least two contact zones P1, P2 which lie on the first and second lateral surface 210, 211.

[0074] As shown by way of example in FIGS. 3-8 where a possible operating work sequence can be seen, the method then provides a work step during which the work tool 125 works the perimeter edge 212.

[0075] Depending on the side of the perimeter edge 212 on which the work tool 125 is operating, at the same time as the work step the following can take place: a coordinated step of moving the sheet 200 (arrows F1), which is made to advance or retract with respect to the work tool 125 in the direction of advance F, and/or a coordinated step of moving the work head 123 along the work axis Y (arrows Y1). The sheet 200 is held in a sliding manner when the relative movement between the sheet 200 and the contact elements 11b, 12b occurs according to the direction of advance F, according to the work axis Y and also according to the combinations of these directions.

[0076] According to the present invention, while a corner of the sheet 200 is being worked (FIGS. 5-8) the method also comprises an orientation step in which the work head 123, and with it the stabilizing device 10, is oriented angularly (angle of orientation ) in a manner that is coordinated with the step of moving the sheet 200 and/or the work head 123, in order to maintain the contact zones P1, P2 always within the first and second lateral surface 210, 211.

[0077] According to some embodiments, the contact zones P1, P2 are advantageously located on the bisector of the corner, in particular on the bisector of the angle comprised between the sides adjacent to the corner.

[0078] In the event that the contact zones P1, P2 have a circular, ellipsoidal or polygonal shape, or other geometric shapes, preferably but not exclusively regular, the method provides to maintain a center of the contact zones P1, P2 on the bisector of the angle , or at least as much as possible in correspondence with such bisector.

[0079] Since the distance D from the peripheral surface of the work tool 125 is fixed, the condition of correspondence of the contact zones P1, P2 with the bisector as above occurs only in proximity to the corners.

[0080] The method provides to start the orientation step the moment in which the contact zones P1, P2 lie on the bisector for the first time. The greater the distance D, the earlier the orientation step takes place.

[0081] Moreover, in general terms, it is possible to correlate the angle of orientation with parameters such as the distance D, the angle comprised between the sides adjacent to the corner, the movement of the sheet 200 in the direction of advance F, and the movement of the work head 123 along the work axis Y.

[0082] It is clear that modifications and/or additions of parts may be made to the method for working sheets 200 as described heretofore, without departing from the field and scope of the present invention, as defined by the claims.

[0083] It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art will be able to achieve other equivalent forms of apparatus and method for holding and performing work on a sheet, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

[0084] In the following claims, the sole purpose of the references in brackets is to facilitate their reading and they must not be considered as restrictive factors with regard to the field of protection defined by the claims.