Automatic machine and method for automatically drilling and milling glass sheets arranged vertically
10702966 ยท 2020-07-07
Assignee
Inventors
Cpc classification
B24B27/0023
PERFORMING OPERATIONS; TRANSPORTING
Y10T408/554
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B23Q7/055
PERFORMING OPERATIONS; TRANSPORTING
B23Q2039/002
PERFORMING OPERATIONS; TRANSPORTING
Y10T29/49996
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B28D1/003
PERFORMING OPERATIONS; TRANSPORTING
Y10T409/308344
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B24B27/0069
PERFORMING OPERATIONS; TRANSPORTING
B23Q1/626
PERFORMING OPERATIONS; TRANSPORTING
Y10T483/1793
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
Y10T29/5107
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B28D1/18
PERFORMING OPERATIONS; TRANSPORTING
B28D7/04
PERFORMING OPERATIONS; TRANSPORTING
Y10T409/30532
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B23B2260/118
PERFORMING OPERATIONS; TRANSPORTING
B23Q3/15706
PERFORMING OPERATIONS; TRANSPORTING
B23P23/02
PERFORMING OPERATIONS; TRANSPORTING
Y10T408/378
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B23Q7/042
PERFORMING OPERATIONS; TRANSPORTING
B23Q39/025
PERFORMING OPERATIONS; TRANSPORTING
International classification
B23B39/22
PERFORMING OPERATIONS; TRANSPORTING
B28D1/18
PERFORMING OPERATIONS; TRANSPORTING
B28D7/04
PERFORMING OPERATIONS; TRANSPORTING
B24B27/00
PERFORMING OPERATIONS; TRANSPORTING
B28D1/00
PERFORMING OPERATIONS; TRANSPORTING
B23Q3/155
PERFORMING OPERATIONS; TRANSPORTING
B23Q39/02
PERFORMING OPERATIONS; TRANSPORTING
B23C1/04
PERFORMING OPERATIONS; TRANSPORTING
Abstract
An automatic machine for drilling and milling substantially flat glass sheets shape, comprising includes a machine body; an input conveyor provided with a motorized roller conveyor or roller belt that conveys the glass sheet by its lower edge; an input conveyance surface provided with idle gliding wheels; an output conveyor provided with a motorized roller conveyor or motorized belt that conveys the glass sheet by means of its lower edge; and an output conveyance surface provided with idle gliding wheels. The machine further includes at least one carriage provided with synchronous horizontal motion along the longitudinal axis X2; and at least one pair of working heads provided independently with a synchronous vertical motion for adjustment and feeding along the axes Y1 and Y2, wherein, each head bears a tool provided with rotary motion (cutting) and feeding motion along the axes Z1 and Z2.
Claims
1. An automatic machine for drilling and milling a substantially flat glass sheet, having a rectangular or other than rectangular shape, the machine comprising: a machine body; an input conveyor provided with a motorized roller conveyor or a roller belt and adapted to convey the glass sheet by means of a lower edge thereof, an input conveyance surface provided with idle gliding wheels; an output conveyor provided with a motorized roller conveyor or a motorized belt and adapted to convey the glass sheet by means of said lower edge; an output conveyance surface provided with idle gliding wheels; a first carriage provided with a horizontal motion along a longitudinal axis X2; at least one pair of working heads, each of the working heads being provided so as to be independently movable for adjustment and feeding in a respective one of two axes Y1 and Y2 having a vertical component, each head bearing a respective tool provided with rotary cutting motion, and each of the tools being provided with a respective feeding motion along a respective one of axes Z1 and Z2 that are perpendicular to a face of the glass sheet, wherein at least one of the tools is adapted to make contact with a surface and therefore with a body of said glass sheet, wherein one of the two heads is also provided with a second carriage that performs a feeding motion along a longitudinal axis X1 while the other of the two heads is provided with at least one sucker that engages the surface of the glass sheet during processes performed by said one head or the opposite head or by the two heads simultaneously.
2. The automatic machine according to claim 1, wherein the first carriage is pre-positioned along the axis X2 as a function of a position of a portion of the glass sheet on which the working heads must work, and is provided with reference devices, in order to actuate slowing and stopping of the glass sheet when the glass sheet is in transit on the conveyors and is moved by the conveyors along the axis X2.
3. The automatic machine according to claim 1, wherein the first carriage is provided with suckers or clamps for coupling to the glass sheet.
4. The automatic machine according to claim 1, wherein the first carriage is capable of intervening so as to aid in repositioning the glass sheet, moved by the conveyors, and the second carriage is capable of performing multiple and progressive feeding motions along the axis X1, after release and subsequent re-engagement of the at least one sucker.
5. The automatic machine according to claim 1, wherein the two working heads are capable of being repositioned along the respective axes Y1 and Y2, so that one of the working heads performs multiple and progressive feeding motions, after disengaging and subsequently re-engaging the at least one sucker.
6. The automatic machine according to claim 1, wherein the at least one sucker is adjustable in position along a plane that is parallel to a plane of the glass sheet, by means of a respective actuator, in order to optimize placement of the at least one sucker as a function of a work field of the tools.
7. The automatic machine according to claim 6, wherein the at least one sucker, actuated by the respective actuator, being actuated by a motor that actuates the feeding motion of said other of said two heads along the axis Z2 and by a motor that actuates the feeding motion of said other of said two heads along the axis Y2, is arranged in a portion of the glass sheet that becomes waste after work on the glass sheet performed by the tools, and mates with said portion of the glass sheet and then guides said waste to a lower region of the machine preset to collect the waste, where said at least one sucker releases the waste.
8. The automatic machine according to claim 1, wherein the second carriage, which moves along the axis X1, is actuated in coordination with a third carriage, which moves along the axis Y1.
9. An automatic method for milling and drilling, the method comprising: providing an automatic machine according to claim 1, for drilling and milling the substantially flat glass sheet, having a rectangular or other than rectangular shape, wherein the two working heads are mutually opposite working heads with an interspace therebetween, wherein the glass sheet can be arranged in the interspace between the two mutually opposite working heads, with a longitudinal axis of the glass sheet extending along the longitudinal axis X2, wherein the tools are abrasive tools for working the glass sheet with a grinding process, wherein in the milling operations, a feeding motion of the tool of a front one of the working heads along the longitudinal axis X1 or the feeding motion of said tool of the front working head along the axis Y1 or a combination of the two feeding motions of the tool of the front working head along the longitudinal axis X1 and the axis Y1, in a condition of interference of the tool of the front working head with the glass sheet, obtained by feeding the tool of the front working head along the axis Z1, is/are actuated only in a condition in which the sheet is coupled to the at least one sucker, which at least one sucker belongs to a rear one of the working heads and is at a border of a work field of the tool of the front working head.
10. The automatic method for drilling and milling according to claim 9, wherein in the drilling operations, the feeding motion of the tool of the front working head along the axis Z1 or the feeding motion of the tool of the rear working head according to the axis Z2 or the combination of the two feeding motions of the tool of the front working head along the axis Z1 and the feeding motion of the tool of the rear working head along the axis Z2 is/are performed only in the condition in which the glass sheet is constrained by the at least one sucker of the rear working head.
11. The automatic method for drilling and milling according to claim 9, wherein the first carriage aids in positioning of the glass sheet, and wherein the tool of the front working head performs multiple and progressive feeding motions along the axis X1, after release and subsequent re-engagement of the at least one sucker with the glass sheet.
12. The automatic method for drilling and milling according to claim 9, wherein the front working head is moved so that the tool of the front working head performs multiple and progressive feeding motions along the axis Y1, after deactivation and reactivation of the at least one sucker.
13. The automatic method for drilling and milling according to claim 9, wherein the tool of the front working head is moved along the axes X1 and Y1 in order to obtain a feeding motion of the tool of the front working head along a feeding path that provides a required shape to the glass sheet.
14. The automatic machine according to claim 1, further comprising a tool magazine in which the tool heads are configured to deposit the tools or pick up further tools.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Further characteristics and advantages of the disclosure will become better apparent from the following detailed description of a particular embodiment of the disclosure, illustrated by way of nonlimiting example in the accompanying drawings, wherein:
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(13) Respectively,
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DETAILED DESCRIPTION OF THE DRAWINGS
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(25) With reference to the accompanying figures, numerals with a single digit (optionally paired with a letter or an index for repetitive elements) designate the parts related to the glass sheet, while the details and constructive mechanisms are designated with three-digit numerals, the first digit of which, when paired with two zeros, is the digit of the main group to which it belongs, and four-digit numerals indicate the machines that constitute the complete automatic line for working the glass sheet (1000 the one according to the present disclosure, 2000 a grinding unit, 3000 a washing unit).
(26) Identifications that use an UPPERCASE letter and a numeral relate to the axes along which the steps of work occur (feeding or adjustment).
(27) In particular, the numeral 1 designates the glass sheet, the sides of which are designated respectively (in the case of a rectangular shape): the front side 1a, the lower longitudinal side 1b and the upper longitudinal side 1c, and the rear side 1d (with reference to the arrangement of the glass sheet 1 in the machine). The adjectives front and rear, in this case, refer to the direction of motion of the glass sheet in the machine (from right to left in the representations of the figures). The faces of the glass sheet 1 are identified respectively by a1, for the one directed toward the operator, and p1, for the opposite one.
(28) With reference to
(29) The machine dedicated to drilling and milling work is substantially constituted by an input conveyor, a main body and an output conveyor.
(30) The input conveyor 100 comprises a motorized roller conveyor 101 for supporting the lower edge 1b of the glass sheet, on which there is a series of motorized support and conveyance rollers 102. The conveyor comprises further a resting surface 103, on which the glass sheet 1 is rested substantially vertically, in the sense described earlier, provided with idle wheels 104. This conveyor comprises a thickness detector 105 of a known type, for measuring the thickness of the glass sheet to be worked before it enters the drilling and milling section, this information being required in order to provide a signal for adjustment, along the axis Z1, of the abrasive tool of the front working head 300 with respect to the face on the operator side of the glass sheet 1, or alternatively being able to arrive as an output signal of the machines arranged upstream, and further comprises a sensor 106 for detecting the presence of the glass sheet in the loading area.
(31) The conveyor is interfaced with any machines arranged upstream, for example the machine 2000 that performs the perimetric grinding work.
(32) The output conveyor 200, which is constituted likewise by a motorized roller conveyor 201 provided with rollers 202, a resting surface 203 provided with idle wheels 204, is instead interfaced with any machines arranged downstream, for example the machine 3000 that performs the washing process. The same conveyor comprises a carriage that actuates the synchronous axis X2 that moves the reference for the placement of the glass sheet 1 in the longitudinal direction with respect to the bridges and working heads 300, 400.
(33) Moreover, the output conveyor 200 comprises a sensor 205 for stopping the glass sheet 1 at the end of the machine or for interface clearance with the downstream machine 3000 that must perform the subsequent work.
(34) Both conveyors, as well as the central machine body, keep the glass sheet at an inclination of approximately 6 with respect to the vertical, in order to provide the already described conditions of stability thereof during transport, parking and work.
(35) The conveyors and the related actuation devices are extensively known and therefore are not discussed here in greater detail.
(36) Between the two conveyors there is the main body of the machine, which contains: the front working head 300, the rear working and sheet fixing head 400, which move in a vertical direction, respectively Y1 and Y2, along vertical bridges of a known type; the tool magazine 500; a system of retractable suckers 600 that are fixed with respect to the structure of the machine.
(37) Respectively, the front working head 300 and the rear working head 400 are constituted in summary as follows. As regards the parts that have a common shape and process: an electric spindle 301, 401, with an axis that is transverse with respect to the face of the glass sheet, provided with the toolholder 302, 402, which in turn is associated with a tool 303, 403 that can be selected among n tool holders+tools, such electric spindle being integral with a slider 304, 404 that runs along the vertical axis Y1, Y2 by means of sliders 305, 405, guides 306, 406 and a mechanical transmission constituted by a rack 307, 407 and a pinion 308, 408, the latter being actuated by means of a reduction unit 309, 409 by a synchronous motor 310, 410 (see
(38) Moving on to the rear working head 400, the corresponding exclusive part (see
(39) An important option (see
(40) The tool magazine 500 also belongs to the central body and is split into a front row 501 and a rear row 502 of the rack type, the operation of which belongs to the background art and simply includes the arrangement of each rack in the work area of the heads for example by means of pneumatic actuators 503 504, in order to interface with the axis of the electric spindle or in the step of retracting the toolholder that ended work or in the step of delivering the toolholder required for the subsequent work (see
(41) As regards the system of retractable suckers of the series 600, the drawings show a solution with two suckers of the type 601, 603, which by means of known pneumatic actuators 602, 604, of the slider type, couple to the rear face p1 of the glass sheet 1 or move away from it, depending on the condition of the operating cycle of the machine described hereinafter. Such suckers having a large surface, together with the suckers 416 arranged on the movable rear head 400 having a smaller surface, retain the glass sheet 1 during work, adequately contrasting the stresses produced by the cutting and feeding (or advancement) motion of the tools, the glass sheet 1 being fixed in multiple positions and therefore locked against translations and rotations.
(42) To complete the description of the output conveyor 200, the mechanisms that actuate the movement of the carriage that actuates the synchronous axis X2 are described finally here in order to highlight the inventive step with respect to the background art CN 203187555 (U), the latter referencing a carriage (designated by the numeral 1 in FIG. 1 of the Chinese patent), the function of which is to fix the rear edge 1d of the glass sheet 1 by means of a system of clamps in order to move it synchronously not only in the positioning (adjustment) step but also in the work step, even supplying the feeding (or advancement) motion for the milling work that has a horizontal orientation or has a horizontal component. The axis X2 of the present disclosure instead arranges a device that interacts with the front edge 1a of the glass sheet 1 for its reference stop, with precise placement since it is actuated by a synchronous motor 210, such placement being performed in order to adjust the region of the glass sheet with a precise phase with respect to the work tool, but the feeding motions that are horizontal or have a horizontal component are actuated exclusively by the tool 301, while the glass sheet 1 remains locked with respect to the slider 404 by means of the suckers 416 (in a quantity from 1 to m) and by means of the suckers 601, 603 (in a quantity typically from 1 to 2 or more). The mechatronic components for performing the above are constituted by the carriage 206, provided with an arm 207 that is pivoted on an axis and oscillates by way of the action of the actuator 209. Such carriage is moved along the axis X2 by the synchronous motor 210 by means of the reduction unit 211 the pinion 212 (not visible but shown in
(43) The arm 207 is oriented in the active state so that the sensors 216 and 217 actuate the speed changes (or also the halting) of the roller conveyor 201 and the block 218 constitutes the mechanical stop for the side 1a of the glass sheet 1 and optionally by means of a microswitch actuates the halting of the roller conveyor 201. The same arm is oriented in the inactive state in order to allow the passage of the working heads 300 and 400 and the transit of the glass sheet 1 at the end of the work along the output conveyor 200. Such orientations are shown in
(44) A section 700, shown only schematically in
(45) Now, we move on to the description of the work cycle as performed on the glass sheet 1 by interaction of the various mechatronic components described earlier, in order to obtain a milling having an open shape, for example on the vertical front side 1a of the glass sheet 1, by means of the tool 303 of the front working head 300.
(46) The glass sheet 1 that arrives from the preceding work machine of the type 2000 (or loaded manually or by means of a magazine on the input conveyor 100 of the machine 1000) is made to advance, conveyed by the support and conveyance rollers 102 of the conveyor 101 and rested on the series of wheels 104, until it stops at the stop foot (pad) 218 after speed reductions activated by the sensors 216, 217, such foot having been pre-positioned, by means of the carriage 206 that runs along the longitudinal axis X2 of the output conveyor 200 as a function of the work to be performed on the glass sheet 1 and oriented in an active position, by means of the actuator 209, as a consequence of the information transferred from the production management system to the process PLC of the machine (by means of a keyboard, USB, net, scanner, etc.). This is the condition shown in
(47) At this point the carriage 206 that bears the arm 207 performs a spacing stroke in order to free the field of action of the front and rear working heads; the rear working head 400, by means of the adjustment motion along the axis Y2, arranges itself at the height (an operation that could also have been performed earlier in coordination with the cycle of the carriage 206) so as to move the set of suckers 416 into a position adapted to retain the flap of the glass sheet 1 as close as possible to the work area of the front tool 303; the suckers 416 that have a complete mating with the rear face p1 of the glass sheet 1 are coupled to such face by the actuators 417 and vacuum is activated in order to mutually retain the suckers and the glass sheet 1; this also occurs for the sucker 601, which has a larger retention capacity and is coupled to the rear face p1 of the glass sheet 1 by means of the actuator 602 and for which vacuum is activated as well. In this condition, shown in
(48) If the work does not comprise the perimeter, as shown for example in
(49) This occurs because if the drilling of the glass sheets occurred on a single face it would evidently entail in exiting through the opposite face.
(50) Once such hole has been provided, in order to perform the milling of the desired shape, one proceeds as described previously for the case of milling that affects the margin of the glass sheet.
(51) Once work, which can be multiple work in the same glass sheet 1, has ended, obviously by means of multiple reiterations of the cycle described earlier, comprising therein the placement of the carriage 206 for the progressive adjustment of the front flap 1a of the glass sheet 1, said sheet is evacuated by means of the action of the conveyors 100 and 200, as shown in
(52) The descriptive detail related to the cycle for picking up and returning the tools is omitted; it involves the operation of the axes Y1 and Y2 with the appearance/disappearance of the racks 501 and 502 of the tool magazine 500 by means of the actuators 503 and 504 and is intuitive from the viewing of
(53) As regards the cutting motion, respectively the front tool 303 and the rear tool 403, accommodated in the tool holders 302 and 402 with quick coupling, which in turn are accommodated in the shafts of the electric spindles 301 and 401, power is supplied by asynchronous motors actuated by inverters in order to obtain a cutting speed that can vary as a function of the type of glass sheet in terms of material, thickness, presence of membranes made of PVB or EVA; type of tools in terms of material of the mix, material of the abrasive, shape and diameter; type of the cooling and lubrication fluid; feed (or advancement) rate.
(54) The glass sheets 1 can have a rectangular or other than rectangular shape (for example, viewing
(55) Conveniently, the tools 303 and 403 are adequately sprayed by a cooling/lubricant flow by means of a plurality of nozzles, respectively 701 and 702, as can be seen in the various figures.
(56) The description given above relates to a machine in which the flow of the material to be worked (glass sheet 1) occurs from right to left, in particular with the sheet arriving from another machine (grinding machine 2000) arranged upstream (to the right) of the described machine and with the sheet destined for another machine (washing unit 3000) arranged downstream (to the left) of the described machine. It is easy to imagine the description and the associated figures in the case of a mirror-symmetrical arrangement or with the origin and destination related to other types of machines or both situations.
(57) Obviously, all the movements linked to the steps of the cycle are mutually interlocked, by means of the aid of a parallel and always active logic system, in order to avoid, during the process, conditions of interference among actuation elements, tools and material being worked (glass sheet 1) that are different from the ones required for drilling and milling work that entail operating process interferences. This is done for the validity of the process, to preserve the integrity of the machine and for the safety of the operators, maintenance technicians and visitors.
(58) It has thus been shown that the machine according to the disclosure achieves the intended aims and advantages. The disclosure is susceptible of numerous modifications and variations, all of which are within the scope of the same inventive concept. Thus, for example, the mechanical solutions for the motions for feeding, adjustment and cutting of the tools, the support and transport of the glass sheet and the actuation means, which can be electrical, electrical-electronic, pneumatic, hydraulic and/or combined, while the control means can be electronic or fluidic and/or combined.
(59) Moreover, the tool 303 can have a profiled shape (complementary with the profile that one wishes to obtain through the thickness of the glass sheet 1, for example beveled at the surfaces a1 and p1).
(60) Obviously, the spindles 301 and 401 can accommodate for this purpose interchangeable tools 303 and 403, which are used alternately not only to perform work with grinding wheels having different profiles but also different grits and mixes in order to obtain different finishes or progressively finer finishes.
(61) Obviously the machine, by operating in a wet environment due to the cooling and lubricant flow directed onto the tools, is provided with protections such as bulkheads, sheaths, accordion-like portions, etc., in order to avoid the escape of fluids and the contamination of the parts that are not suitable to bear contact with liquids.
(62) Furthermore, since the drilling and milling work entail the production of waste; not only constituted by classic glass dust produced by the grinding action performed by the tools 303, 403, but most of all constituted by actual flat pieces of glass sheet that correspond to the removed parts (complement of the openings provided minus the part converted into dust by the tools); the machine is provided with adapted chutes or mechanized devices (for example conveyor belts of the grid type) in order to remove said waste. This is in combination or not with the foregoing description regarding the adjustability of the suckers 416 and the possibility to use the axis Y2 in order to guide the work waste to a lower height.
(63) Moreover, the work waste that derives from drilling, of the so-called core type, can be moved away by way of the action of the stream of cooling/lubrication water that is directed through the hollow part of the front tool 303 or, as an alternative, by way of the action of an air stream that also is directed through the hollow part of the front tool 303.
(64) The constructive details can be replaced with other technically equivalent ones. The materials and dimensions can change according to the requirements, in particular arising from the dimensions (base, height, thickness) of the glass sheets 1.
(65) In particular, the means for supporting and moving the glass sheet 1, besides the ones described, comprise all the equivalents, such as for example belts (as shown in
(66) In particular, the means for positioning the glass sheets 1 can be coupled thereto by way of suckers or grippers.
(67) Obviously the industrial application is assuredly successful, since in many applications not only the perimetric edge of the glass sheet must be worked, as already occurs according to multiple by now widespread known methods, but also portions of the surface of the glass sheet 1 require additional work, such as drilling and milling according to the description, work which also is by now widespread but by resorting to known methods, which are mediocre in terms of quality, since the region affected by drilling and/or milling is not adequately retained and optionally even insufficient in terms of productivity, since they are combined with the grinding work. Examples of requirements of this drilling and/or milling work are several and specifically for at least the following products: handrails, railings, steps, shelters, dividing walls and walkable areas (for which the evolution of the standards has led to a particular attention: as regards the fixing modes, which occur with work on the surface and affect the thickness of the sheet, both for drilling and for milling; as regards the type of such work. Such standards are UNI 7697/2014, which replaces UNI 7697/2007 (Safety criteria in glassmaking applications). Moreover, the market of glass for enclosures of buildings and of insulating glass used in continuous faces and in structural faces is expanding continuously and in the last decade has been increased by all the configurations that require the use of special glass fixed to the structure no longer by means of simple retention at the perimeter but by means of couplings that act locally on the surface by means of holes and/or multiple millings thereof.
(68) In all these described situations, the glass sheets are subjected to operating loads constituted by the people (and therefore with protection priority for example against falling into empty space), or by atmospheric loads such as wind, snow, thermal stresses, seismic stresses, etc. (which glassmaking facilities must withstand, otherwise a risky situation would occur for the safety of people); obviously the provision of the holes and millings assumes a substantial importance both in terms of process, which must not introduce the possibility of triggering cracks, and in terms of geometry, which must interface with the sometimes complex structures for coupling, and in terms of aesthetics, if the regions that are worked remain visible with architectural or interior decoration functions.
(69) Moreover, one field that is growing daily and also requires, in addition to the grinding of the perimetric edge, the drilling and milling of the glass sheets 1 is constituted by all applications that resort to the use of tempered glass sheets, such as those of interior decoration or electric household appliances.
(70) Furthermore, a relevant and expanding field of use is the nautical and naval one, the glass sheets assuming an important proportion both in enclosure structures (windows and portholes) and in protection structures and interior decoration structures.
(71) The drilling and milling of the glass sheet constitutes a very important added value that qualifies the product, especially if the work is performed with machines and methods that are less expensive than currently commercially available.
(72) Moreover, the spread of shapes that are other than rectangular since they are polygonal or curvilinear or mixed enhances even more the value of the present disclosure, in contrast with the limitation of many widespread machines that can only work rectangular shapes.