TOOL FOR LOCALLY COOLING A GLASS SHEET

Description

[0001] The present invention belongs to the field of glass forming. Previous art

[0002] The development of sensor systems such as cameras, lidar, etc., is increasing rapidly to make vehicles more autonomous. However, the arrival of lidar and cameras on the front of vehicles necessitates increasingly large viewing areas, which, in the case of lidar, must be particularly neutral to electromagnetic waves. The nature of the glass currently used, as well as the assembly method of laminated glass, makes this impossible with existing glazing. Several solutions have been developed to overcome these limitations, such as glass treatments or the use of two different types of glass. In the latter case, an outer pane allows electromagnetic waves to pass through, while the inner pane is cut out in the relevant area. Another problem is glass forming; the increasingly large dimensions and shapes of the openings make the glazing more fragile during handling.In gravity forming, the inner pane (small pane) is supported by the outer pane (large pane) during its forming phase. However, in a sheet-by-sheet process, where the glass is formed between two lower and upper molds, the panes are handled and formed one by one. Breakage can be more frequent because the cutting process promotes the development of weak points.

[0003] EP2766184B1 relates to a manufacturing process for laminated glazing comprising cutting and cooling by contact with a local cooling tool of an area of ​​the glazing. Summary of the invention

[0004] The present invention therefore seeks to resolve the drawbacks of the prior art by providing a cooling tool that allows treatment of an area with a complex shape and large surface area.

[0005] In this respect, the invention relates to a local contact cooling tool for a sheet of glass at a temperature above 450°C, referred to as the contact tool, comprising at least one contact surface intended to come into contact with the sheet of glass, said tool comprising an internal channel for the circulation of a cooling fluid, in particular air, characterized in that the contact surface has a non-circular shape, said tool comprising a lower shell and an upper shell assembled to form a chamber into which the cooling fluid is sent, the upper shell carrying said contact surface, and in that the tool comprises a nozzle connected to the channel and opening into said chamber, said nozzle comprising a plurality of openings is configured to diffuse the cooling fluid homogeneously in the chamber.

[0006] In one example, the contact surface extends over all or part of the upper shell.

[0007] For example, the contact surface is a solid surface or a contour

[0008] In one example, the pipe opens onto the lower hull.

[0009] According to one example, the nozzle has the same shape as the contact face of the tool

[0010] According to one example, the nozzle has a different shape from the contact face of the tool.

[0011] According to one example, the holes in said nozzle are regularly spaced.

[0012] According to one example, the distribution of the holes in said nozzle is uneven.

[0013] In one example, the cooling tool is mounted on a movable damping system. In another example, the cooling tool is mounted on at least one moving element to be applied to the surface to be cooled; this moving element includes at least one spring element.

[0014] The invention further relates to a glass sheet bending station in which a glass sheet at a temperature above 450°C is brought between an upper form and a lower form to be shaped, characterized in that the lower form is arranged to integrate at least one tool according to one of claims 1-11.

[0015] The invention further relates to a method for cooling an area of ​​a sheet of glass, said sheet of glass being brought into a bending station according to claim 12, said method consisting of, when the sheet of glass is pinched between the upper form and the lower form, pressing said at least one cooling tool, by at least one contact surface, against the sheet of glass to inject a cooling fluid so as to create compressive stresses in the area of ​​the sheet of glass in contact with said cooling tool. Description of the figures

[0016] Other features and advantages will become clear from the description given below, which is indicative and in no way exhaustive, with reference to the attached drawings, in which: THE figure 1 represents a view of a line equipped with a furnace and a crowning station; the figure 2 And 3represent a total and partial view of a bending station according to the invention; the figure 4a , 4b , 4c And 5 represent a total and partial view of a cooling tool according to the invention; the figures 6 to 7 represent the possible solutions for the nozzle of the cooling tool according to the invention; the figure 8 represents variations on the arrangement and configuration of the holes for the nozzle of the cooling tool according to the invention; the figure 9 represents a variant of the spring-mounted cooling tool according to the invention; the Figures 10 And 11 represent a variant of the cooling tool with drainage holes. Detailed description

[0017] On the figure 1A furnace 1 is shown in which a sheet of glass 2 travels along a roller conveyor 3. During its time in the furnace 1, the sheet of glass 2 is brought to its softening temperature, above 450°C. The sheet of glass 2 is then conveyed, still supported by the conveyor 3, to a bending station 4.

[0018] This bending station 4 is where the softened sheet of glass is manipulated to take its almost final shape.

[0019] In the bending station 4, a pressing frame 5 is positioned below the plane defined by the roller conveyor 3. When the glass sheet 2 reaches the top of this frame, components not shown in the figures ensure precise positioning of the glass sheet, and its movement is then stopped by the rollers stopping in the bending zone. The pressing frame 5 then passes through the roller bed 3 to lift the glass sheet.

[0020] As mentioned previously, the pressing frame 5 has the desired shape for the glass sheet and allows the glass sheet to be formed. The pressing frame 5 is designed to pass through the roller bed 3.

[0021] The pressing frame 5, having taken charge of the glass sheet 2, moves, by means of a linear actuator, to press the glass against a curved form 6 positioned above the pressing frame 5. The shaping of the glass sheet is therefore achieved by pressing the glass sheet between the curved form 6 and the pressing frame 5. At the end of the pressing, a suction system ensures that the glass sheet is perfectly pressed onto the upper form.

[0022] The crowning form 6 (also called the upper form) comprises a crowning face, preferably solid, i.e., continuous and uniform, whose shape is preferably square but may take other shapes such as rectangular or any other shape. The crowning face has a surface or area defined by the projection of the contour of the upper form onto a horizontal plane and is at least equal to the surface or area defined by the projection of the outer contour of the pressing frame.

[0023] Glass sheets are preferably made of a mineral glass containing at least 40% silica. This is generally a calcium silicate glass. Other types of glass may be used.

[0024] The glass sheets have a thickness ranging from 0.8 to 5 mm. Specifically, glass sheets with thicknesses of 1.6 mm, 2.1 mm, or 2.6 mm are targeted. The glass sheets may or may not be coated with one or more thin layers, such as one or more IR-blocking coatings (e.g., silver) or one or more Low-E coatings; these coatings are not included in the glass sheet thickness ranges specified in this application.

[0025] According to the invention, a local cooling tool 8 is arranged to locally cool the glass sheet as seen at the figure 2 . The purpose of this local cooling is to create compressive stresses for cutting the glass later, the cut surface being preferably greater than that of a conventional drilling, i.e. greater than 60mm².

[0026] The local cooling tool 8, visible at figures 4a ,4b , 4c And 5 The device comprises at least one contact surface 81 intended to be in contact with the glass sheet 2 for its local cooling. This contact surface 81 is located on the face of the local cooling tool 8 opposite the glass sheet 2. The contact surface 81 extends over all or part of the face of the tool 8 opposite the glass sheet 2. This contact surface 81 may be solid or a contour. This contour may be that of the face of the cooling tool 8 or be within said face. The contour appears, on the face of the cooling tool 8, as a protruding portion of the face of the cooling tool 8.

[0027] The cooling tool 8 comprises a cooling head 82 in the form of a casing 820 forming an enclosure 820a. This casing 820 has an upper face 821 facing the glass sheet and a lower face 822. The upper face 821 carries the contact surface 81. The lower face is arranged for mounting the cooling head 82 in the bending station 4. For this purpose, the lower face 822 is such that it allows the anchoring of at least one translational element 84, such as a jack, which is defined as a mechanical or electromechanical element enabling the translation of two elements relative to each other. Preferably, the cooling head is supported by two translational elements 84.

[0028] The housing 820 is formed by two shells: an upper shell 823 and a lower shell 824. Preferably, these shells 823 and 824 are half-shells. The upper half-shell is the half-shell that has the upper surface 821 of the housing 820 bearing the contact surface 81, while the lower half-shell carries the translational element(s) 84. The enclosure 820a formed by the half-shells 823 and 824 is suitable for the circulation of a cooling fluid. Such a cooling fluid F can be a liquid or a gas. This cooling fluid F is supplied to the tool via a pipe 85. This pipe 85 opens onto the lower half-shell.

[0029] Within the enclosure 820a formed by the half-shells 823, 824, a nozzle 86 is arranged. This nozzle 86 is connected to the pipe 85 and includes openings 861 so as to diffuse the cooling fluid F as seen in the figure 6For this purpose, the lower half-shell 824 is provided with a base 87 comprising an outer portion, outside the casing 820, and an inner portion, i.e. opening into the enclosure 820a of the casing 820. The outer portion is used for the connection of the pipe and the inner portion is used for the connection of the nozzle.

[0030] Therefore, the cooling fluid F circulates within the enclosure 820a formed by the half-shells. This cooling fluid tends to cool the half-shells 823 and 824. Since the upper half-shell 823 carries the contact surface 81 with the glass sheet, the latter is cooled. This cooling induces stress on the glass sheet.

[0031] According to the invention, the contact surface 81 has a non-circular shape. This non-circular shape can be a parallelepiped such as a square or rectangle, or a more complex shape such as a trapezoid, or any other non-circular shape. If the contact surface is the entire upper surface or the outline of the upper half-shell 823, then the upper half-shell 823, and therefore the cooling head, also has a non-circular shape.

[0032] The non-circular shape of the contact surface requires adjustments to allow cooling of the glass sheet which remains homogeneous despite the inhomogeneity of the shape of the envelope.

[0033] While the shape of the cooling tool and / or the contact surface imposes constraints, the surface area of ​​the glass sheet to be treated also imposes constraints. Indeed, for a surface area less than 20 cm², the diffusion of a cooling fluid is straightforward because the small surface area necessitates a chamber that will be cooled quickly and uniformly. For a surface area greater than 20 cm², constraints arise. In fact, if the surface area increases, this means that the distance between the edge of the enclosure and the nozzle also increases. This increase in surface area requires cooling to be as uniform as possible.

[0034] To achieve this, one solution is to use an 86 nozzle with a circular shape, as can be seen in the figure 6This nozzle 86 is in the form of a puck, that is to say, a circular part having a side wall. This side wall is provided with a series of openings 861 through which the cooling fluid is ejected, expelled.

[0035] Since the shape of the nozzle 86 differs from that of the casing, the nozzle 86 is designed to allow for homogeneous fluid diffusion, enabling uniform cooling of the glass sheet. To achieve this, two parameters are adjusted: the first parameter is the interval between two adjacent openings 861, and the second parameter is the diameter of the openings 861 as seen in the figure 8 .

[0036] Indeed, with a circular nozzle 86 equipped with regularly spaced openings 861, there is a possibility that portions of the casing 820, and more specifically, portions of the casing's periphery, may be less effectively cooled. This is due to the difference in shape between the nozzle 86 and the casing 820.

[0037] By varying the gap between the openings 861, it is possible to narrow the gap between the openings 861 to diffuse the cooling fluid F towards portions with a complex shape.

[0038] The diameter parameter of the orifices 861 is related to the distance between the nozzle 86 and the casing 820. Indeed, with a circular nozzle and a square casing, the entire casing 820 is not equidistant from the nozzle 86. To compensate for this, the diameter of the orifices is modified. Since the flow rate remains the same, the variation in diameter results in a variation in pressure. The orifices 861 with a smaller diameter therefore have a higher pressure and thus allow the cooling fluid to be projected over a greater distance.

[0039] It is possible to have openings 861 with different spacings and diameters to ensure the most homogeneous diffusion of the cooling fluid F. By having openings 861 with different diameters, the nozzle 86 is able to diffuse the fluid at different distances, thus achieving more homogeneous diffusion and therefore more homogeneous cooling.

[0040] The openings 861 of the nozzle 86 can also be located on different lines so as to diffuse the cooling fluid at different heights.

[0041] In a second solution visible at the figure 7 The nozzle 86 is designed to have a shape mirroring that of the casing 820. If the casing 820 has a trapezoidal shape, then the nozzle is also trapezoidal, with the sides of the casing 820 parallel to the sides of the nozzle. This solution is ingenious because it allows for a nozzle with identical and evenly distributed openings. Indeed, since the nozzle 86 has the same shape as the casing, all the openings 861 are equidistant from the casing. In this case, the diameter of the openings does not need to vary.

[0042] In one variant, the nozzle 86, which may have the same or a different shape from the casing 820, is designed to prevent the coolant from being directed into a corner of the casing. This is because, in the case of a non-circular casing, the casing has sides and corners. These corners are areas where the coolant can concentrate.

[0043] The nozzle 86 of the tool according to the invention is therefore arranged so as not to have any opening(s) 861 opposite a corner of the casing 820. To this end, the base used to mount the nozzle 86 includes, on its inner portion, a keying feature. This keying feature ensures that, when the nozzle is mounted on said inner portion, the nozzle is in a specific position.

[0044] In another variant visible at the figure 9The translational element(s) 84 carrying the tool's housing further include spring means 814 for mounting the tool on a spring, with damping. These spring means 814 may comprise at least one spring or at least one elastic ring. This spring or elastic ring mounted on a translational element is used to eliminate the risk of marking. Indeed, when the tool is applied to the hot glass sheet, there is a risk of marking the sheet by the tool. With the spring means, the stress exerted by the tool on the glass sheet is reduced, thus decreasing the risk of marking.

[0045] In another variant visible at Figures 10 And 11The tool 8 is designed to facilitate the localization of cooling at the periphery of the contour. Indeed, one of the purposes of the cooling tool 8 according to the invention is to create a constrained area to facilitate easier cutting. In this embodiment, the casing includes, at the level of the lower half-shell 824, a plurality of holes 824a. These through holes 824a allow the cooling fluid to be evacuated. Thus, the nozzle 86 ejects the cooling fluid into the enclosure towards the contour of the casing. The fluid is then rapidly evacuated through the holes 824a of the inner half-shell. This embodiment is particularly advantageous for cutting a large surface area.Indeed, in the case of a large surface to be cut, the present variant is advantageous in that it allows the contour to be cooled uniformly to have a cutting "line" that is easy to cut rather than having uneven cooling of the entire surface.

[0046] Therefore, the cooled area in which compressive stresses are located at the contour of the cooling tool 8.

[0047] The cooling tool 8 according to the invention is used during the process of shaping a sheet of glass. In a glass sheet forming process, the sheet, brought to its softening temperature, above 450°C, is then conveyed, still supported by the conveyor 3, to the bending station 4.

[0048] In the bending station 4, a pressing frame 5 is positioned below the plane defined by the roller conveyor 3. When the glass sheet 2 reaches the top of this frame, it is positioned within the station, and the pressing frame 5 then moves through the roller bed 3 to lift the glass sheet. The glass sheet is lifted to contact the upper mold to give it the desired shape. The cooling tool 8, integrated into the bending station according to the invention, is at least simultaneously with the pressing frame via the translation element(s). Once in contact with the glass sheet, the cooling tool is activated so that the cooling fluid F is sent into the pipe to be diffused by the nozzle 86. This diffusion cools the contact surface locally, creating local compressive stresses.

[0049] The cooling fluid is injected into the 820a chamber of the tool as soon as there is contact with the glass sheet or subsequently according to parameters such as time, temperature of the glass sheet for example.

[0050] After the cooling stage, which creates compressive stresses, a breaking stage is performed. This breaking stage consists of fracturing the area of ​​the glass sheet corresponding to the area that was in contact with the cooling tool. This area can be just the edge or the entire surface.

[0051] The breaking stage consists of making a cutting line and then breaking it by applying a laser or water jet or by any other possible means.

[0052] Of course, the present invention is not limited to the illustrated example but is susceptible to various variations and modifications that will become apparent to those skilled in the art. The crowning station may include several cooling tools according to the invention. These cooling tools may have shapes which, when combined, form the area to be cut. This possibility is advantageous in that it allows a large surface to be divided into at least two smaller, easier-to-cool surfaces. Furthermore, it is possible to have a complex shape that is divided into less complex shapes for cooling purposes.

[0053] In another embodiment, the upper face 821 of the casing 820 comprises at least two contact surfaces 81. These contact surfaces 81 may be identical: symmetrical or not, or different: one surface may be solid, the other a contour. It is possible that, within the enclosure 820a, one or more nozzles 86 are housed, one per contact surface 81.

Claims

1. A tool (8) for locally cooling a glass sheet (2), by contact, to a temperature of greater than 450°C, which tool is referred to as a contact tool and comprises at least one contact surface (81) intended to come into contact with the glass sheet, said tool comprising an inner pipe (85) for the flow of a cooling fluid, in particular air, characterized in that the contact surface (81) has a non-circular shape, said tool comprising a lower shell (824) and an upper shell (823) assembled to form an enclosure (820a) into which the cooling fluid is fed, the upper shell (823) carrying the contact surface (81), and in that the tool comprises a nozzle (86) connected to the pipe (85) and opening into the enclosure (820a), said nozzle (86) comprising a plurality of openings (861) for diffusing the cooling fluid in a consistent manner into said enclosure (820a).

2. The tool according to the preceding claim, characterized in that the contact surface (81) extends over all or part of the upper shell (823).

3. The tool according to the preceding claim, characterized in that the contact surface (81) is a solid surface or a contour.

4. The tool according to one of claims 1 to 3, wherein the pipe (85) opens onto the lower shell (824).

5. The tool according to the claim 1, wherein said nozzle (86) has the same shape as the contact face of said tool.

6. The tool according to claim 1, wherein said nozzle (86) has a shape different from that of the contact face of said tool.

7. The tool according to claim 5, wherein the holes of said nozzle (86) are evenly distributed.

8. The tool according to claim 6, wherein the distribution of the openings (861) of said nozzle (86) is uneven.

9. The tool according to one of the preceding claims, characterized in that the tool is movably mounted with shock absorption.

10. The tool according to the preceding claim, characterized in that said tool is mounted on at least one translation element (84) to be applied in contact with the surface to be cooled, this translation element comprising at least one spring element.

11. The tool according to one of the preceding claims, characterized in that the lower shell (824) is provided with a plurality of holes (824a) for discharging the cooling fluid.

12. A glass sheet bending station (4) into which a glass sheet (2) at a temperature of greater than 450°C is fed between an upper mold (6) and a lower mold (5) to be shaped therein, characterized in that the lower mold (5) is arranged to incorporate at least one tool (8) for locally cooling according to one of the claims 1 to 11.

13. A method for cooling a zone of a glass sheet, said glass sheet being fed into a bending station (4) according to claim 12, said method consisting in, when the glass sheet (2) is pinched between the upper mold (6) and the lower mold (5), placing said at least one tool (8) for locally cooling, by at least one contact surface (81), on the glass sheet (2) to inject a cooling fluid therein so as to create compressive stresses in the zone of the glass sheet (2) in contact with said tool (8) for locally cooling.