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(11) | EP 2 599 588 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Method and machine for cutting glass sheets |
| (57) A large glass sheet (2) is cut according to a predefined cutting program (P) using
at least one fluid cutting jet (22) and moving the large sheet (2) in a first direction
(A) and the jet (22) in a second direction (20) to perform a first and at least a
second cut for separating a smaller sheet (3) from the large sheet (2); at least one
of the smaller sheets (3) being removed from the remaining part of the large sheet
(2) before separating a successive smaller sheet (3) from the remaining large glass
sheet (2).
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[0002] In particular, the present invention relates to a method for cutting a large glass sheet by means of a jet of pressurized cutting fluid, conveniently water with an abrasive material.
[0003] In the field of cutting glass sheets by means of water jets, cutting machines are known to be used, in which, in a cutting station, a distributor head provided with at least one nozzle for distributing the fluid jet is moved along a cutting path defined by a predetermined cutting program so as to progressively divide the sheet into a plurality of smaller sheets having shape and geometry defined by the cutting program.
[0004] In the cutting station, the sheet to be cut is normally placed on a support device which must allow the passage of the fluid jet passing through the sheet whatever the position of the distributor head and which, therefore, inevitably, is worn, hence is to be periodically replaced. This involves periodic costs, inevitable machine stops and, hence, costs for lost production.
[0005] In any case, the sheet to be cut is kept on such a support until the entire cutting program has been completed. Only at this point is the water jet interrupted and the different smaller sheets are removed from the cutting station.
[0006] The removal of the smaller sheets from the cutting station also requires an inevitable machine stop and hence further costs for lost production. The machine stop for the removal of the smaller sheets from the cutting station may in part be decreased by providing two cutting stations in parallel, but this involves a significant increase in space in addition to an increase in the cost of the machine.
[0007] In any case, both the inlet sheet and each smaller sheet have been completely immersed in the cutting fluid, hence handling is difficult and they must in any case be cleaned.
[0008] The object of the present invention is to provide a cutting method, which allows the above-mentioned problems to be resolved in a simple and affordable manner, and, in particular, directly producing finished smaller sheets of whatever shape from the large sheet without interruptions or dead times in the cutting process.
[0009] According to the present invention, a method is provided for cutting a large glass sheet, as claimed in claim 1.
[0011] According to the present invention, a machine is provided for cutting a large glass sheet, as claimed in claim 10.
[0012] The invention will now be described with reference to the accompanying drawings, which illustrate a nonlimiting exemplary embodiment thereof, in which:
figure 1 shows, diagrammatically and substantially in blocks, a machine for cutting a large glass sheet made according to the dictates of the present invention;
figure 2 shows an example of a cutting program, the sheet followed by the machine in figure 1;
figure 3 is a sectional view in enlarged scale, of the machine in figure 1;
figures 4a-4d show a sequence of steps for cutting the glass sheet to make the cutting program in figure 2; and
figure 5 shows a variant of a detail in figure 1.
[0013] Numeral 1 in figure 1 indicates, as a whole, a fluid jet cutting machine for cutting a large glass sheet 2, monolithic stratified or coated and making a plurality of sheet sections or smaller glass sheets 3, according to a predefined cutting program P, for example of the type shown in figure 2. In the example shown in figure 2, the smaller sheets 3, some of which are indicated with 3a, 3b and 3c, are near to each other along two mutually orthogonal directions. In other words, several smaller sheets 3 are arranged near to each other along perimetral edges of the large sheet to define perimetral portions of the sheet or of the residual sheet when partially cut.
[0014] Machine 1 comprises a base 4, a horizontal plane 5 for supporting the large sheet 2 to be cut, an intermediate zone or sheet cutting station 6 and two lateral zones 7 and 8 arranged on sides opposite to the cutting station 6 and each housing a respective sheet support device 9, 10, for example of the rolling body type, in itself known and diagrammatically shown. A device 12 is associated with zone 7, for example of the motorized belt or bridge with suction cups type, it also in itself known and not described in detail, which can be enabled to move sheet 2 away from and towards the cutting station 6 in a longitudinal direction A crossing, in the specific case, an entrance and an exit of machine 1. Instead, associated with zone 8 is a configurable motorized evacuation device 13 equal to, or different from, device 12, in any case independent from device 12 and, for example of the suction cup type, having independent motorized rollers or belts adapted to positively couple to each of the smaller sheets 3 provided by the cutting program P, and removing each of the smaller sheets 3 from the cutting station 6 when the smaller sheets 3 are detached from the remaining part of the large sheet 2, as will be better detailed below.
[0015] With particular reference to figures 1 and 3, housed in the cutting station 6 is a fluid cutting device 15, which comprises a rectilinear guide 16 extending parallel and in raised position with respect to the support plane 5 and coupled to base 4 in longitudinally fixed position and, conveniently, adjustable in height with respect to the support plane 5.
[0016] Guide 16 slidingly carries, coupled, a motorized distributor head 18 for moving in opposite directions along guide 16 along a rectilinear path 20 orthogonal to the longitudinal direction A and provided with a distributor nozzle 21 adapted to direct a jet 22 of pressurized cutting fluid, for example water with an abrasive material, onto the support plane 5 and, in use, onto an upper face 2a of sheet 2.
[0017] According to a variant shown in figure 5, coupled to guide 16 are several independent distributor heads 18 adapted to each direct a related jet 22 of cutting fluid onto a related portion of surface 2a of sheet 2 to be cut.
[0018] Again with reference to figures 1 and 3, machine 1 also comprises a fixed slit 25 obtained through the support plane 5 beneath guide 16 between the devices 9 and 10 and in a rectilinear direction coinciding with the orthogonal projection of path 20 on the support plane 5. Conveniently, slit 25 has an approximating width L exceeding the diameter of the fluid jet(s) 22 and in any case such as to allow the free crossing of plane 5 by the jets 22.
[0019] The cutting fluid progressively leaving the nozzles 21 and crossing the large sheet 2 and, therefore, slit 25, is collected in a gutter container 26, which forms part of device 15, extends in correspondence to and only beneath slit 25 and houses a mass M of cutting fluid capable of dampening the jet(s) 22 of cutting fluid passing through slit 25.
[0020] Again with reference to figures 1 and 3, device 15 also comprises two deflectors 30 or inlet or conveyor plates integrally connected to guide 16 in facing positions. The deflectors 30 extend on longitudinal opposite sides of the jet or jets 22 and slit 25 and converge towards each other and towards the support plane 5 to convey the fluid impacting on the large sheet 2 into slit 25.
[0021] Lastly, device 15 comprises pair of outlet or evacuation plates 31 arranged beneath the support plane 5 in facing positions and on opposite sides of slit 25 to receive the fluid leaving slit 25, thus removing it from surface 2b of sheet 2 arranged in contact with the supports 9 and 10 and conveying it into the gutter container 26. The plates 31 converge towards each other and towards slit 25 and are partially inserted into the gutter container 26 to retain, within container 26, the fluid sprays generated following the impact of the jet(s) 22 against the mass M of fluid housed in container 26. The plates 31 are fixed with respect to base 4 of machine 1, or are supported by a motorized motion device, in itself known and not shown in the accompanying drawings, which moves the plates 31 away from and towards the support plane 5 in a direction substantially orthogonal to the support plane 5, for example to facilitate the picking of the smaller sheets 3 from station 6.
[0022] The distributor head 18 or the distributor heads 18 coupled to guide 16, device 12 for the motion of the large sheet 2 in direction A, the evacuation device 13 and the device for moving the barriers 31, when present, are commanded and controlled by a unit 35 of command and control, which comprises a memory block 36 where the cutting program P is saved and a command and control block 37.
[0023] In machine 1 described, the smaller sheets 3 are made and removed from the cutting station 6 as follows.
[0024] Firstly, the large sheet 2 is brought to the entrance of machine 1 and by means of device 12 advances on the support plane 5 in direction A to station 6. At this point, with reference to figure 4a, supposing to start cutting the large sheet 2 thus creating the smaller sheet 3a (figure 4a) using a single jet 22 arranged outside the longitudinal edge 2c of the large sheet 2, the large sheet 2 is fed to station 6 until the cutting line K1 coincides with the projection of path 20 of jet 22 on plane 5. At this point, head 18 is fed along path 20 thus performing a first cut along line K1, after which the large sheet 2 is retracted by means of device 12 thus performing a second cut along K2 (figure 4a) so as to detach the smaller sheet 3a from the remaining part of the large sheet 2. According to a different embodiment mode, the two cuts K1 and K2 are performed in inverted order. The smaller sheet 3a is therefore picked by device 13 and removed from the cutting station 6 (figure 4b). During the motion of the smaller sheet 3a or when motion is complete, head 18 is translated along path 20 and jet 22 is brought to the beginning of the cutting line K4 (figure 4c). As soon as the smaller sheet 3a is in such a position as not to interfere with the remaining part of the large sheet 2, the large sheet 2 is advanced by device 12 thus performing a first cut along the cutting line K4. While always keeping jet 22 enabled, head 18 is translated along path 20 and a second cut is performed along the line K5 with the subsequent separation of the smaller sheet 3b. At this point, as for the smaller sheet 3a, the smaller sheet 3b is also removed from station 6 by means of device 13. With similar motions along path 20 and in direction A, possibly combined with each other to obtain curved sections, each of the smaller portions 3 is progressively cut or separated from the remaining part of the large sheet 2 and immediately removed from station 6 before the successive smaller sheet 3 is separated from the remaining part of the large sheet 2. The last smaller sheet 3 being evacuated, a new large sheet 2 is fed onto the support plane 5 and cut as described above.
[0025] According to a different operating mode, two or more smaller sheets 3 are cut from the large sheet 2 and left on the part of the support plane 5 defined by device 10, that is to the exit side of the smaller sheets 3 from machine 1, until their presence along or near slit 25 is an obstacle to the advancing of the remaining part of the large sheet 2 past slit 25, that is past the orthogonal projection of path 20 on the support plane 5, after which they are separated individually, or in a block, from station 6 thus removing the obstacle to the advancing of the large sheet 2 thus allowing, in such a manner, progressive and continuous cutting of the large sheet.
[0026] It is apparent from the above that, with respect to known embodiment modes, the above-described cutting process is a continuous process, that is without interruptions and/or machine stops and this allows the production schedule to be increased by also using machines with the same volumes as machines normally used.
[0027] Instead, with regards to the embodiment features of machine 1, it is apparent that the motion of the jet 22 or the jets 22 only within the through slit 25 prevents any contact with the devices 9 and 10 for supporting the large sheet 2 and the smaller sheets 3, thus eliminating, thereby, machine stops for the replacement or maintenance of the supports 9, 10.
[0028] In addition to this, the supports 9 and 10 in described machine 1 are practically never in contact with the cutting fluid, or in any case only marginally, due to the presence of the deflectors 30, which contain the fluid sprays within the impact zone of jet 22 on the large sheet 2 and convey the fluid into slit 25. Thereby, the fluid involves an extremely limited zone of the glass sheets circumscribed to the one of the cutting line and this results in undoubted advantages in cutting the large sheets 2, the surface 2a of which is coated by layers of sensitive materials such as, for example, low-emissivity ones.
[0029] Instead, the plates 31 provided at the exit of jet 22 from the large sheet 2 allow all the fluid which impacts the large sheet 2 to be conveyed to the container 26 beneath.
[0030] It is apparent that the plates 31 and 32 could have different shapes and dimensions than the ones described and be for example tubular type barriers. Unlike known containers which necessarily have in plane extensions equal to if not greater than those of the support plane 5 of the machine, container 26 has transversal dimensions, that is slightly larger in the longitudinal direction A than the width of slit 25 and, however, such as to contain a minimum mass of fluid sufficient to dampen the jets 22 outlet from the large sheet 2.
[0031] It is apparent from the above-mentioned that modifications and variants may be made to described machine 1. In particular, the order in which the cuts are performed to separate each of the individual smaller sheets 3 from the large sheet 2 and, consequently the motions of the large sheet 2 or of jet 22 in the cutting station 6, may be different from that described. Regardless from the number of nozzles 22 used and from the cutting sequence selected, the permanence of the smaller sheets 3 separated from the remaining part of the large sheet 2 on the support plane is not to hinder or prevent the motion of jet 22 or of the remaining part of the large sheet 2 through or in station 6 for the cutting of the successive smaller sheets 3.
1. A method for cutting a large glass sheet, the method comprising the steps of feeding
the large glass sheet to a cutting station, of directing at least one jet of pressurized
cutting fluid onto said large glass sheet and of cutting the large sheet according
to a predefined cutting program creating a plurality of smaller glass sheets near
to each other, each smaller glass sheet being cut from said large sheet by carrying
out a first and at least a second cut on the large sheet that are mutually transversal,
characterized in that said smaller sheets are cut in succession and at least one of said smaller sheets
is removed from said cutting station before the cutting of the large sheet is completed,
by coupling it to motorized means of gripping and handling.
2. The method according to claim 1, characterized in that each of the smaller glass sheets is removed from the remaining part of said large
glass sheet and from said cutting station before a successive smaller glass sheet
is detached from the remaining part of the large glass sheet.
3. The method according to claim 1 or 2, characterized in that said smaller glass sheets are removed by advancing them in a direction of motion
having at least one component parallel to at least one of said first or second cuts
and independently from the motion of the large sheet during the cutting step.
4. The method according to any of the preceding claims, characterized in that said smaller glass sheet is removed from said station during a cutting step of said
large glass sheet.
5. The method according to any of the preceding claims, characterized in that the cutting of said large glass sheet is carried out by arranging the large sheet
on first and second supports delimiting a fixed elongated slit between them; said
first and second cuts are performed by moving said fluid jet within said slit in a
first rectilinear direction and said large sheet in a second rectilinear direction
transversal to said first rectilinear direction, and sheets arranged along said slit
are formed in succession.
6. The method according to claim 5, characterized in that said smaller glass sheets are removed from said station by coupling them to motorized
retaining devices associated with said second supports and movable away from and towards
the cutting station along a direction parallel to said second direction.
7. The method according to claim 5 or 6, characterized in that said fluid jet leaving said sheet is dampened by using a layer of the same cutting
fluid arranged in correspondence to and only beneath said slit.
8. The method according to claim 5, characterized in that it comprises the further step of retaining said cutting fluid impacting said large
glass sheet within barriers able to convey the fluid impacting the large sheet into
said slit.
9. The method according to claim 5, characterized in that it comprises the further step of retaining said cutting fluid coming out from said
cuts progressively made in said large glass sheet by means of further barriers able
to remove the cutting fluid from the surface of the large glass sheet arranged in
contact with said supports.
10. A machine for cutting a large glass sheet, the machine comprising a cutting station,
feeding means to feed the large sheet to the cutting station, at least one distributor
head for supplying and directing at least one jet of pressurized cutting fluid onto
said large glass sheet thus creating a plurality of smaller glass sheets near to each
other and means of command and control to move said pressurized fluid jet and said
large glass sheet in said station according to a predefined cutting program comprising
for each said smaller glass sheet a first and at least a second cut that are mutually
transversal, characterized in that it further comprises configurable motorized means of gripping and handling for selectively
coupling to said smaller glass sheets and removing at least one of said smaller glass
sheets from said cutting station before completing the cutting of said large glass
sheet.
11. The machine according to claim 10, characterized in that said cutting station has an exit for said smaller glass sheets opposite to an entrance
for said large glass sheet and in that said configurable motorized means of gripping and handling are independent from said
means for feeding said large sheet.
12. The machine according to claim 10 or 11, characterized in that it comprises first and second supports delimiting a horizontal support plane for
said large sheet and with a fixed elongated slit between them; said means of command
and control moving said fluid jet within said slit in a first rectilinear direction;
said feeding means moving said large sheet through said cutting station in a second
rectilinear direction transversal to said first rectilinear direction to perform said
first and second cuts.
13. The machine according to claim 12, characterized in that said configurable means of gripping and handling are associated with said second
supports and comprise means of coupling to said smaller glass sheets movable away
from and towards the cutting station in a direction parallel to said second direction.
14. The machine according to claim 12 or 13, characterized in that it further comprises a fixed elongated container extending in correspondence to and
only beneath said slit to house a mass of cutting fluid for dampening said jet of
cutting fluid.
15. The machine according to any of claims 12 to 14, characterized in that it comprises entrance barriers arranged above said support plane and in correspondence
to said slit to convey the fluid impacting the large sheet into said slit.
16. The machine according to any of claims 12 to 15, characterized in that it comprises exit barriers arranged beneath said support plane to remove the cutting
fluid from the surface of the large glass sheet arranged in contact with said supports.