SUPPORT FOR GRAVITY BENDING OF GLASS

Description

[0001] The invention relates to the field of thermal curvature supports for glass, more particularly for large glass with strong curvatures.

[0002] Gravity bending of large, highly curved glass panes onto frames, particularly skeleton frames, presents a challenge because, at the beginning of the bending process, the uncurved glass extends significantly beyond the frame. Consequently, as soon as the glass begins to soften from heat, the protruding portion tends to collapse outwards, adopting a curvature opposite to the desired final shape. During the bending process, the edge of the glass must slide inwards along the frame so that, at the end of the bending, it is correctly positioned. Typically, a few millimeters of glass protrude beyond the frame to promote the development of permanent edge compression stresses. However, the slightly collapsed portion of the glass outside the frame impedes this sliding. As a result, the cycle time is increased, and the risk of uncontrolled deformation is greater.Furthermore, the glass may be insufficiently curved, or even flat, or irregularly curved, at the periphery, leading to a peripheral shape outside of tolerance.

[0003] In the present application, the glass is in the form of a single sheet or, more generally, a stack of several sheets, or more generally, a stack of two sheets. For the sake of simplicity in describing the invention, the term "glass" is used to refer to a single sheet or a stack of sheets. Whether it is a single sheet or several stacked sheets, the glass comprises two principal external faces, referred to herein as the first principal face and the second principal face. Gravity bending is carried out on a gravity support by holding the glass on its first principal face, which is facing downwards. In the case of a stack, the sheets remain stacked throughout the bending and cooling process to ensure identical forming of all the sheets intended to be assembled into the final glazing.The joining of these glass sheets in the final laminated glazing is thus carried out under better conditions, leading to a higher quality laminated glazing.

[0004] The curved glass according to the invention is particularly intended for use in vehicles, especially road vehicles such as cars, trucks, and especially buses or coaches, which use particularly large windshields. Generally, the glass is mounted on the vehicle in the form of laminated glass, combining several sheets of glass separated by a polymer material, particularly PVB. Preferably, all the glass sheets intended to be combined in a single laminated glass unit are curved together in the stacked state so that their shapes are as identical as possible.

[0005] In the context of this application, the compression edge stress values ​​are determined by a Sharples device marketed by Sharples Stress Engineers.

[0006] Gravity glass bending devices are notably taught by EP338216, US2993303, US4626267, US5167689, US5660609, US9771296, US3227538, US6076373, EP0338216.

[0007] The invention relates to a device for the gravity bending of a sheet of glass or a stack of sheets of glass, said the glass, comprising a frame, said support frame, and an extension external to at least a portion of said support frame, said extended portion, said extension comprising a contact track for the glass, said extension being able to allow access of ambient air to at least a part of the peripheral area external to the support frame of the lower face of the glass located opposite the extended portion of said support frame when the glass is in its final curved form, the extension being movable or removable, said extension being contiguous to the support frame during at least part of the bending and being separated from the support frame during at least part of the cooling in order to leave a space between the support frame and the extension.

[0008] The aim is for the edge of the glass to extend beyond the supporting frame at the end of the curving process and during the cooling phase leading to the glass's settling. This allows the edge to cool more rapidly than the glass directly above the frame, consequently experiencing greater edge compression stresses. This portion of the glass extending beyond the supporting frame is the peripheral zone outside the frame. Access to this entire peripheral zone, or only a part of it, is provided, for example, through openings in the extension. Advantageously, the edge of the glass extends beyond the supporting frame by 2 to 15 mm in its final curved form (at the end of the curving process), whether the frame is extended or not.

[0009] In its final curved shape, the glass rests on the entire perimeter of the support frame. The extension is not necessarily present opposite the entire perimeter of the support frame, but for at least a portion of this perimeter, referred to as the "extended portion." This extension, which extends the support frame outwards, supports the glass to prevent it from sagging and therefore includes a contact surface to make contact with the glass.

[0010] The extension according to the invention extends the support frame outwards and therefore has curves that extend those of the support frame, whether these curves are parallel or radial with respect to the frame. Similarly, in order to perform its extension function, the contact surface of the extension is aligned with the contact surface of the support frame. Il Therefore, there is no step when going from one to the other.

[0011] The device according to the invention comprises a gravity support in the form of a frame, referred to as the support frame, which supports the periphery of the glass at the end of the curvature and at least during part of the cooling process, at least during the glass's settling. This support frame is preferably covered with a refractory fibrous material such as a metallic mesh, well known to those skilled in the art for its contact with glass. This fibrous material forms a kind of cushioning that softens the contact of the tool with the glass and also acts as thermal insulation. When such a material is used, the contact surface for the glass on the support frame is made of the refractory material. Apart from the extension that is the subject of the invention, the width of the contact surface between the support frame and the glass is generally in the range of 3 to 20 mm.The extension adds to the contact track of the support frame a contact track extending outside the support frame by a distance d between 5 and 50 mm. These contact track widths are given when viewed perpendicular to the contact track.

[0012] Gravity curvature can, if necessary, be assisted by the pressure of a counter-mold pressing on the upper surface of the glass in a manner similar to the teaching of EP640569A1 (see its figure 2 Generally, however, no tool touches the upper surface of the glass, nor its edge, during the bending process. Whether or not an upper mold is used for bending, no tool touches the upper surface of the glass in its peripheral area, or indeed anywhere on this upper surface, nor its edge, at least from the beginning of cooling until the glass has set.

[0013] In order for the required edge compression stresses to develop, the extension allows ambient air access to at least part, or even all, of the periphery of the underside of the glass during a portion of the cooling process corresponding to the period during which the glass sets. It is during the setting of the glass that the permanent compression and tensile stresses are established. In this way, the peripheral area undergoes the cooling necessary to achieve the desired edge stresses, in particular at least 4 MPa, preferably at least 8 MPa. The extension according to the invention allows ambient air access to at least part, or even all, of the periphery of the underside of the glass. This refers to the periphery of the glass at the points where an extension is located, that is to say, the "extended portion(s)" of the support frame.Indeed, the extension does not usually cover the entire frame but only the portions corresponding to the greatest slippage of the glass on the frame during curvature.

[0014] In particular, access for ambient air to the periphery of the underside of the glass can be facilitated by a gap between the support frame and the extension. In this case, during the curving process, the glass slides along the extension, and the edge of the glass ends up above the gap between the frame and the extension at the end of the curvature. Preferably, in this case, the glass, once curved and extending beyond the frame, no longer touches the extension. In this case, ambient air has access to 100% of the peripheral area of ​​the underside of the glass that lies outside the support frame, whether or not it is an "extended portion." The gap between the frame and the extension can be in the range of 2 to 20 mm, preferably from 3 to 15 mm. In an embodiment not part of the invention, the extension can be fixed relative to the frame and, in particular, permanently attached to the frame, in which case a gap between the frame and the extension is constant.

[0015] There may be no gap between the extension and the frame, but in that case, openings exist in the extension to allow ambient air access to at least a portion of the periphery of the underside of the glass, outside the supporting frame. This portion of the glass is the area above the openings. Preferably, the openings allow ambient air access to at least 30%, and even at least 50%, and even at least 80%, or more, of the peripheral area of ​​the underside of the glass that lies outside the supporting frame.

[0016] With or without openings, the extension is movable or removable (relative to the extended portion of the support frame it covers) so as to allow ambient air access to at least part of the periphery of the underside of the glass during at least part of the cooling process. Specifically, the extension is in contact with the frame during at least part of the curvature and then moves away from the frame by a suitable distance to leave a gap between the frame and the extension during at least part of the cooling process. In the case of a removable extension, the extension is in contact with the frame during at least part of the curvature and then retracts so as not to be present near the frame during at least part of the cooling process. The removable extension is preferably retracted after the start of the cooling process so as to be sufficiently far from the edge of the glass to no longer influence the formation of stresses within the glass during its curing.Thus, in the case of a movable or removable extension, the extension is attached to the support frame during the curvature phase and is separated from the support frame for at least part of the cooling process to leave a gap between the support frame and the extension. In particular, the extension is advantageously retracted after the cooling process has begun.

[0017] If the extension is not removable and remains attached to its extended portion of the support frame, it should preferably be thin to minimize its influence on the temperature of the air surrounding the edge of the glass during cooling. Therefore, it should be as thin as possible while still being rigid enough to avoid deformation upon contact with the glass. For example, this extension could have a thickness ranging from 1.5 mm to 4 mm.

[0018] The frame with the extension can be the only support in contact with the glass during the curving process and at least during the cooling and setting of the glass. This frame can be fixed, i.e., without hinges. The frame can also be hinged. In this case, the frame includes one or two hinges that rise during the curving process. One side of the frame that rises via a hinge gives the glass more curvature, and in particular its rise. This side therefore corresponds to a longitudinal edge of the glass, the glass acquiring its transverse curvature between its two longitudinal edges through a transverse curvature.

[0019] The support frame typically supports the glass at the end of the curving process and during the initial cooling phase, thus giving the glass its final shape. Therefore, the support frame according to the invention can also be called the "finishing frame," as the curving process generally ends on it. In addition to this support frame, the device according to the invention may also include other glass support elements, generally used at the beginning of the curving process. Indeed, in the case of complex curves, it is recommended to accentuate the curves of the curving device by gravity during the curving process itself to make it more gradual, thereby reducing the risk of counter-curving (curves opposite to those desired in the corners). To achieve this, devices with moving parts are used during the curving process.

[0020] In particular, the device according to the invention can conform to one of the following configurations: A) The support frame may include one or two hinged sections that can be raised during the curving process. The support frame then includes sections that support the glass at the beginning of the curvature, called "roughing sections," which are replaced during the curvature by "hinged sections." The hinged sections have contact tracks that are more curved than the roughing sections. Fixed sections of the support frame can come into contact with the glass regardless of whether the hinged sections are raised or not. Such a support therefore has a roughing shape that receives the glass in its flat state and supports it at the beginning of the curvature, and a final shape that supports the glass at the end of the curvature. The principle of this type of support, with variable geometry for some of its contact tracks but including fixed contact tracks used for both the roughing and finishing of the curvature, is taught in particular by... figures 3 to 6of EP448447A1; the extension according to the invention is primarily intended to equip the articulated parts of this type of device. B) In addition to the support frame, the device according to the invention may include a non-articulated roughing frame supporting the glass at the beginning of the curvature; the support frame with more pronounced curves replaces this roughing frame during the curvature; the support frame here acts as a finishing frame because it is in contact with the glass at the end of the curvature; these two frames are distinct from each other, that is to say, they do not include a contact track common to the support frame and the roughing frame; the principle of this type of double frame supporting the glass one after the other is taught in particular by the figures 1 to 4of EP705798A1; the extension according to the invention is intended to equip at least the parts of the support frame that give the glass its curvature; C) in addition to the support frame, the device according to the invention may include a frame called a non-articulated roughing frame supporting the glass at the beginning of the curvature; a support frame comprising at least one articulated part replaces this roughing frame for the glass during the curvature, its articulated part(s) rising during the curvature; the support frame here plays the role of a finishing frame because it is in contact with the glass at the end of the curvature; the principle of this kind of double frame supporting the glass one after the other, the support frame comprising at least one articulated part, is taught in particular by figure 8 of WO2004 / 103922A1; the extension according to the invention is intended to equip the articulated parts of the support frame;D) In ​​addition to the support frame, the device according to the invention may include a frame called a hinged or non-hinged finishing frame supporting the glass at the end of the curvature; the support frame, with less pronounced curvatures, supports the glass at the beginning of the curvature before the finishing frame, the latter replacing it during the curvature; these two frames are distinct from each other, that is to say, they do not include a contact track common to the support frame and the finishing frame; the principle of this type of double frame supporting the glass one after the other is taught in particular by the; figures 1 to 4 of EP705798A1; in this variant, the extension according to the invention equips at least part of the peripheral area outside the support frame, which here plays the role of a roughing frame; in this variant, this support frame generally surrounds the finishing frame seen from above.

[0021] In variants B), C), and D) the two frames are capable of being animated by a relative vertical movement to move the glass from the roughing frame to the finishing frame.

[0022] In all variants, the contact track of the extension is preferably at the same height as the contact track of the support frame, at least at the end of the glass's sliding motion on the extension. Thus, if the extension is movable or removable, the extension is at the same height as the contact track of the support frame when the extension is in a position flush against the frame.

[0023] When the device according to the invention includes a support comprising at least one articulated part, the raising of the articulation can generally occur automatically due to the softening of the glass. This type of support includes a counterweight system adjusted so that raising the articulation does not require significant force. Thus, when the glass, not yet highly curved, rests on this support, the counterweight system is adjusted so that the articulated part lowers under the weight of the glass. Then, during the softening and collapse of the glass as it curves, this articulated part rises. The raising of the articulated part can be controlled by a locking and unlocking system operated from outside the device, notably as taught in EP448447.The raising of the articulated part can also be slowed by a chain controlled from the outside by a flexible or rigid link, the chain imposing a speed of ascent of the articulated part. A preferred device according to the invention is of type C), the articulated support frame surrounding the roughing frame in top view.

[0024] Thus, the device according to the invention may include a roughing frame to support the glass at the beginning of the curvature, the roughing frame and the support frame being capable of relative vertical movement to move the glass from the roughing frame to the support frame. The roughing frame supports most of the glass's weight, or even all of its weight, at the beginning of the curvature, while at the end of the curvature, the support frame supports most of the glass's weight, or even all of its weight. Preferably, the support frame surrounds the roughing frame when viewed from above. The glass extends beyond the roughing frame so that, during the relative vertical movement, the support frame takes hold of the glass by this portion extending beyond the roughing frame. The support frame may be hinged and thus include one or two hinged sections capable of rising during the curvature. Generally, the extension is fitted to one or two of the hinged sections.

[0025] The invention also relates to a method for manufacturing curved glass comprising the gravity bending of a sheet of glass or a stack of sheets of glass, said glass, on the device of one of the preceding claims, the glass sliding on the extension during the bending and the extension being mobile or removable, said extension being joined to the support frame during at least part of the bending and being separated from the support frame during at least part of the cooling in order to leave a space between the support frame and the extension.

[0026] The glass produced using the device of the invention is generally curved in two directions orthogonal to each other and therefore has two depths of curvature. This type of curvature is called complex curvature, sometimes spherical, as opposed to cylindrical curvature, in which the glass is curved in only one direction. The curved glass according to the invention generally has a plane of symmetry perpendicular to it and passing through the midpoint of two of its sides (also called "strips"), generally its so-called transverse sides, that is to say, those that are substantially horizontal when the glass is mounted on the vehicle. The depth of the transverse curvature is called the "sweep" and the depth of the longitudinal curvature is called the "double curvature."Transverse curvature is that which creates transverse curves between the longitudinal sides of the glass, that is, curves that are approximately horizontal when viewed from the front of the vehicle, with the glass mounted on the vehicle. Longitudinal curvature is that which creates longitudinal curves between the transverse sides of the glass, that is, curves that are approximately vertical when viewed from the front of the vehicle, with the glass mounted on the vehicle. WO2010136702 teaches, in particular through its... Figures 1a and 1b how the "arrow" and "double-bombing" are determined and the same definitions are used in the context of this application.

[0027] The lenses generally comprise four sides (also called "stripes"), two of these sides being the longitudinal sides, which appear substantially vertical when viewed from the front of the vehicle on which they are mounted, and the other two being the transverse sides, which appear substantially horizontal when viewed from the front of the vehicle on which they are mounted.

[0028] The glass relevant to the present invention is generally large. The invention is particularly suited to glass where at least one dimension of the main face in its flat state before curvature exceeds 2000 mm, and even exceeds 2400 mm. The extension according to the invention supports at least one edge, substantially orthogonal to this large dimension.

[0029] The flat glass used before curving can have a main face dimension greater than 2400 mm and a main face dimension greater than 1600 mm. The final curved glass can have a main face dimension greater than 2200 mm and a main face dimension greater than 1500 mm when projected onto a plane. The final curved glass can have a rise greater than 250 mm, or even greater than 280 mm, or even greater than 300 mm. The final curved glass can have a double rise greater than 80 mm, or even greater than 90 mm, or even greater than 100 mm. In particular, glass with a rise between 290 and 350 mm, combined with a double rise between 90 and 130 mm, can be produced.

[0030] The glass comprises one or more stacked sheets of glass, the thickness of each sheet of glass being within the range of 0.5 to 6 mm, in particular from 2.5 to 4.5 mm. For example, two or three such sheets of glass can be curved together in the stacked state.

[0031] The figures discussed below are not to scale.

[0032] There figure 1This illustrates a problem of the prior art solved by the invention. A portion of a hinged bending frame is schematically represented. A flat, unbent glass pane 1 rests on a bending device comprising a frame with a fixed part 2 and a hinged part 3. Initially, the glass is still flat and only touches the frame at a few points. Due to the significant concavity of the final glass pane and its large size, the glass overhangs considerably by a distance d from the frame. During the bending process, the glass softens and the hinge closes. The glass must slide on the frame so that, at the end of the bending process, only a few millimeters of the glass overhang the frame. In b), the glass is being bent, but the part 4 of the glass overhanging the frame tends to sag downwards, giving the glass in 5 a curvature opposite to that ultimately desired.

[0033] There figure 2A top view of the figure represents a curved frame 10 comprising two fixed parts 11 and 12 and two hinged parts 13 and 14. Two portions 15 and 16 of the hinged parts of the frame, referred to as extended portions, are provided with extensions 17 and 18 according to the invention. These extensions are external to the frame and located opposite the extended portions of the frame. These extensions are fixed to the hinged parts, leaving a permanent gap (19, 20) between the frame and the extension. These gaps allow access of ambient air to the periphery of the underside of the glass located opposite the extended portions of the frame, at least during part of the cooling process.

[0034] There figure 3 illustrates the sliding of the edge 30 of the glass on an extension 31 according to an embodiment not part of the invention during the curvature. The extension 31 is of the type shown in the figure 2that is, with a space 32 between the extension and the portion of the support frame 33 fitted with the extension 31. This portion of the support frame is on a hinged part, which is lowered in a) before the start of the curvature and at the beginning of the curvature, then begins to rise in b) while the glass is being curved and is fully raised in c). At the end of the curvature in c), the edge 30 and even the edge 34 of the glass is above the space 32, protruding from the support frame 33 by a distance d2 within the range of 2 to 15 mm. Ambient air therefore has access to the periphery of the lower face of the glass located opposite the extended portion of the frame 33. Since the glass is curved in this final position, cooling will cause permanent compressive stresses at the edge of the glass. The configuration in b) is intermediate between those of a) and c).The extension 31 adds to the contact track of the support frame 33 a contact track 35, which extends outside the support frame by a distance d1 between 5 and 50 mm.

[0035] There figure 4 illustrates a portion of frame extended by an extension 41 according to an embodiment not forming part of the invention.

[0036] This extension 41 is fixed to the frame 40 without any gap between them. The extension includes openings 42 to allow at least partial access of ambient air to the periphery of the underside of the glass facing the extended portion of the frame. Since it is important that this air access occurs at least during the cooling process, with the glass in its final shape and position on the frame, the openings 42 are preferably located close to the frame 40. The sum of the areas of the openings preferably represents at least 30%, and even at least 50%, and even at least 80%, or more, of the peripheral area of ​​the underside of the glass that lies outside the supporting frame. The outermost part 43 of the extension may indeed be without openings since it only supports the glass at the beginning of its curvature.

[0037] There figure 5 illustrated in top view in a) and in cross-section in side view in b) (in the cutting plane Vb)-Vb) of the fig 5aA glass 84, either at the end of its curvature or during cooling, rests on a device according to an embodiment not part of the invention. The glass thus has its final shape. The device comprises a support frame 80, at least a portion of which is extended by an extension 81 according to the invention. This extension comprises a solid strip 82, i.e., without openings, whose principal direction is parallel to the frame 80, and tabs 83 connecting the strip 82 to the support frame 80. The frame 80 and a portion of the tabs 83 are visible through the glass 84. The spaces 85 between the tabs 83 and between the support frame 80 and the strip 82 form openings 85 allowing access of ambient air to at least a portion of the peripheral area 86 outside the support frame 80 of the underside of the glass. At the very beginning of the curvature, the edge 88 of the glass was on the band 82 at level 87.It slid down the band 82 and the legs 83 to end up above the orifices 85 at the end of the curvature.

[0038] There figure 6Figure a) schematically illustrates a device according to the invention in which an extension 50 is removable relative to the portion 51 of the support frame that it extends. This portion is on a hinged part and connected to a fixed part 52 via a pivot joint 53. In a), the glass 54, still almost flat, already rests on the extension 50 even though the hinge 51 is not yet raised. This prevents any sagging of the glass edge outside the support frame from the very beginning of the curvature. In b), the continuation of a) is shown during the curvature, when the hinge 51 is raised. The extension 50 has followed the hinge so as to provide the glass with a continuous shape of the portion 51 of the hinged part. This mobility of the extension is made possible by the fact that it is fixed to an arm 55, itself movable around a sliding pivot 56.In c), once cooling had begun, the extension 50 was retracted to allow ambient air access to the periphery of the underside of the glass facing the extended portion of the frame, at least during part of the cooling process. In this embodiment, the extension can be said to serve both as a blank (or third strip) and as an extension of the support frame. The extension is, in fact, independent of the support frame. The positioning and retraction of the extension are controlled, at least in part, from outside the device.

[0039] There figure 7This schematically illustrates a device according to an embodiment not forming part of the invention, comprising a roughing frame 60 on which the glass rests at the beginning of the curvature and a support frame 61 on which the glass rests at the end of the curvature. During the curvature, a relative vertical movement between the roughing frame and the support frame moves the glass from the roughing frame to the support frame. During this movement, and also afterward, the two articulated parts 62 and 63 rise during the curvature by pivoting around pivots 64 and 65. The representation is schematic, and of course, the pivots 64 and 65 are not connected to the roughing frame 60. The device is shown in its final position at the end of the curvature, the glass (not shown) no longer touching the roughing frame 60.Two portions 66 and 67 of the support frame are provided at the level of their articulated parts 62 and 63 with extensions according to the invention 68 and 69 provided with orifices (not shown) suitable for allowing access of ambient air for the formation of edge stresses during the freezing of the glass during its cooling.

Claims

1. A device for the gravity bending of a glass sheet or a stack of glass sheets, called the glass, comprising a frame, called the support frame, and an extension outside at least one portion of said support frame, called the extended portion, said extension comprising a contact track for the glass, said extension being capable of allowing access for ambient air to at least a part of the peripheral area outside the support frame for the lower face of the glass which is located facing the extended portion of said support frame when the glass is in its final bent shape, the extension being movable or removable, said extension being adjacent to the support frame during at least part of the bending process and being spaced apart from the support frame during at least part of the cooling process so as to leave a gap between the support frame and the extension.

2. The device as claimed in the preceding claim, characterized in that the contact track of the extension is at the height of the contact track of the support frame.

3. The device as claimed in any of the preceding claims, characterized in that the access for the ambient air is allowed by a space between the support frame and the extension.

4. The device as claimed in any of the preceding claims, characterized in that the access for the ambient air is allowed by openings in the extension.

5. The device as claimed in any of the preceding claims, characterized in that the device comprises an initial frame for supporting the glass at the start of bending, the initial frame and the support frame being drivable with a relative vertical movement to cause the glass to pass from the initial frame to the finishing frame.

6. The device as claimed in the preceding claim, characterized in that the support frame surrounds the initial frame in a top view.

7. The device as claimed in any of claims 1 to 4, characterized in that the device comprises a finishing frame for supporting the glass at the end of bending, the finishing frame and the support frame being drivable with a relative vertical movement to cause the glass to pass from the support frame to the finishing frame.

8. The device as claimed in the preceding claim, characterized in that the support frame surrounds the finishing frame in a top view.

9. The device as claimed in any of the preceding claims, characterized in that the support frame is hinged and comprises one or two hinged parts that can be raised in the course of the bending.

10. The device as claimed in the preceding claim, characterized in that the extension is fitted to one or two of the hinged parts.

11. The device as claimed in any of the preceding claims, characterized in that the extension has a thickness in the range from 1.5 mm to 4 mm.

12. A method of manufacturing bent glass comprising the gravity bending of a glass sheet or of a stack of glass sheets, called the glass, on the device as claimed in any of the preceding claims, the glass sliding on the extension in the course of bending and the extension being movable or removable, said extension being adjacent to the support frame during at least part of the bending process and being spaced apart from the support frame during at least part of the cooling process so as to leave a gap between the support frame and the extension.

13. The method as claimed in the preceding claim, characterized in that the glass in its final bent shape projects beyond the support frame by 2 to 15 mm.

14. The method as claimed in any of the preceding method claims, characterized in that it comprises the cooling of the glass on the device in its final bent shape during its setting.

15. The method as claimed in the preceding claim, characterized in that the cooling creates edge stresses of at least 4 MPa, or preferably at least 8 MPa, in the glass.

16. The method as claimed in any of the preceding method claims, characterized in that the glass comprises one or more glass sheets, the thickness of each glass sheet being in the range from 0.5 to 6 mm, notably from 2.5 to 4.5 mm.

17. The method as claimed in any of the preceding method claims, characterized in that the flat glass before bending has a larger main face dimension of more than 2400 mm and a smaller main face dimension of more than 1600 mm.

18. The method as claimed in any of the preceding method claims, characterized in that the final bent glass has, in projection on a plane, a larger main face dimension of more than 2200 mm and a smaller main face dimension of more than 1500 mm.

19. The method as claimed in any of the preceding method claims, characterized in that the final bent glass has a deflection of more than 250 mm, or even more than 280 mm, or even more than 300 mm, and a double bend of more than 80 mm, or even more than 90 mm, or even more than 100 mm.

20. The method as claimed in the preceding claim, characterized in that the extension is retracted after the start of the cooling.