WO2021165431A1 - Device and method for press-bending glass panes - Google Patents

Abstract

The invention relates to a device (1) for press-bending glass panes (8), comprising: - a first press-bending mould (5) with a first press face (6), - a second press-bending mould (9) with a second press face (10), which comprises a press frame (12) and one or more press inserts (13), the press inserts (13) each forming a strut in the mould and being arranged at least partly within a region (15) delimited by the press frame (12), the press frame (12) and the one or more press inserts (13) each having a press face portion (14, 14') which together form the second press face (10), the second press face (10) being formed in a manner complementary to the first press face (6), the two press-bending moulds (5, 9) being movable relative to one another in the vertical direction such that a glass pane (8) can be press-bent between the two press faces (6, 10), the one or more press inserts (13) each being designed such that a region (B) with alternating curvature of the glass sheet (8) can be press bent by each press face portion (14').

Description

Device and method for press bending of glass panes

The invention lies in the technical field of the manufacture of glass panes and relates to a device and a method and for press bending of glass panes, as well as their use.

Glazing for automobiles is typically curved in shape. In order to create a bend, the glass pane, which is flat in its initial state, is heated to at least its softening temperature, typically by means of radiant heaters. The glass pane is then shaped in a single or multi-step process. In the industrial series production of glass panes, various press-bending processes are used, which have often found their way into the patent literature.

For example, in WO 2012/080072 a method with a step-wise bending of glass panes in the edge and inner area is described. In WO 2004/087590 and WO 2006072721 a method is described in which the glass pane is first pre-bent on a press frame by gravity, followed by press bending by means of an upper and lower press bending mold. In EP 255422 and US 5906668 the bending of a glass pane by suction against an upper press bending form is described.

With the known press-bending processes, bent glass panes can be produced in a variety of ways. So-called press frames are often used in order to guarantee a high optical quality of curved glass panes that allows a largely distortion-free view. Such a press frame does not make contact with the entire surface of the glass pane during press bending, but only with a peripheral edge area. However, there are limits to the degree of bending that can be achieved. In particular, Glascheibenfor men with local areas with strong curvature (small radii of curvature) and / or strong ker change in curvature (high curvature gradients), which are located relatively far from the edge of the glass pane, are difficult or impossible to implement. This applies in particular to elongated areas with alternating curvature, which are also referred to as "edges". Such edges are very aesthetically pleasing.

In order to realize complex glass pane shapes, it is helpful to further heat the affected areas locally in order to ensure greater malleability of the glass pane there. This is relatively easy to achieve with discontinuous bending processes. In such Biegever, which are known for example from EP 1358131 A1 and EP 2463247 A1, the Glass pane is typically stored on a transport mold and remains during the bending process one or more times for a relatively long time in one place, including in the heating furnace. There, a desired temperature profile can then be generated on the glass pane by specifically designing the radiant heaters. The complex, discontinuous bending processes are particularly common for high-quality composite panes such as windshields.

In addition, there are also continuous bending processes that are carried out at a significantly higher rate, especially for single-pane safety glass such as side windows or rear windows. The glass sheet is continuously moved by the bending device, in particular on a roller conveyor system, without lingering in one place. These processes give the glass manufacturer significantly fewer opportunities to influence the heating of the glass pane and to generate a specific temperature profile. For example, WO 2017/178733 A1 discloses such a bending method.

US 5974834 A and CN 105502903 A each show a method in which a glass pane is bent which has an opening. Here, a bending form is used in which a smaller inner frame is attached within an outer frame, which is used for heavy-duty bending of a circumferential edge of the opening. For this purpose, the hot glass pane is placed on the lower bending form. The inner frame is not used for press bending the glass pane. JPS6424034 shows a method in which two nested press frames and a central support are used. US20110123730 A1 shows a method in which a glass pane is provided with an alternating curvature in the edge area by two press frames lying one inside the other.

In contrast, the object of the present invention is to provide an improved press bending process and a corresponding device for press bending of glass panes compared to the known press bending process, with which the Her position of glass panes with local areas with strong curvature and / or strong change in curvature, especially in Inner area of the disc is made possible with high optical quality at the same time. It is essential here that elongated areas of the glass pane with alternating curvature (edges) can be produced in any position. In addition, such glass panes should be able to be produced in a time-efficient and cost-effective manner. These and other objects are achieved according to the proposal of the invention by a Vorrich device and a method for press bending glass panes with the features of the associated claims. Advantageous refinements of the invention emerge from the subclaims.

The device and the method are partially presented jointly below, with explanations and preferred configurations relating equally to the device and method. If preferred features are described in connection with the method, it follows that the device is also preferably designed and suitable accordingly. Conversely, if preferred features are described in connection with the device, it follows that the method is also preferably carried out accordingly.

In the context of the present invention, the term “pre-bend” denotes an incomplete bending of the glass pane in relation to a defined or definable end bend (end geometry or end shape) of the glass pane. The pre-bend can, for example, make up 10 to 80% of the final bend. The term "bend" can refer to a pre-bend or a final bend.

The glass pane has a terminal edge region adjoining a glass pane edge, for example an edge region that encircles the glass pane in a strip-like manner. For example, the strip width is in the range from 3 to 150 mm. The edge of the glass pane is formed by a (cut) surface which is typically arranged perpendicular to the two opposing glass pane surfaces. The edge area delimits a central or inner area of the glass pane, which is directly adjacent to the edge area. The glass pane can be subjected to a bend in the edge and / or inner area. The glass panes preferably have no openings.

The term "laterally" or "laterally displaceable" denotes a movement with at least one horizontal movement component through which a component can be arranged laterally relative to another construction part.

The device for press bending glass panes typically comprises several structurally and functionally delimitable zones or chambers. One component is a bending zone or bending chamber for press bending of heated glass panes, which is advantageous is equipped with a heating device for heating glass panes. In particular, for this purpose the bending chamber can be brought to a temperature which enables glass panes to be plastically deformed and which is typically in the range from 600.degree. C. to 750.degree.

The bending chamber for press bending glass panes comprises a first or upper press bending mold which has a pressing surface for contacting a glass pane. For ease of reference, the pressing surface of the first press bending die is referred to as the "first pressing surface". The first pressing surface can conceptually be divided into an outer surface section and an inner surface section. The outer surface section is preferably shaped to be suitable for an edge bend in the edge region of the glass pane. The inner surface section is preferably suitably shaped for a surface bending in the central or inner region of the glass pane surrounded by the edge region. In the working position, the first pressing surface of the first press bending mold is oriented in the direction of gravity, i.e. downwards. The first pressing surface of the first bending press mold is preferably formed over the entire surface, with openings such as suction holes (see below) or the like also being able to be provided.

The device for press bending glass panes comprises at least one means for securing a glass pane on the first pressing surface of the first press bending mold. The means for fixing a glass pane advantageously comprises a pneumatic suction device for sucking in a gaseous fluid, in particular air, through which the glass pane can be drawn against the first pressing surface with the aid of negative pressure. For this purpose, the first pressing surface can for example be provided with at least one suction hole, advantageously with a plurality of suction holes, for example evenly distributed over the pressing surface, at each of which a negative pressure can be applied for a suction effect on the first pressing surface. As an alternative or in addition, the suction device can have an apron surrounding the first pressing surface, by means of which a negative pressure can be generated on the pressing surface. The suction device generates a typically upwardly directed flow of a gaseous fluid, in particular air, which is sufficient to hold the glass pane on the first pressing surface. This makes it possible in particular to place a lower press bending mold or a pre-tensioning frame for receiving the glass pane fixed on the pressing surface below the glass pane. Alternatively or in addition, the means for fixing a glass pane advantageously comprises a pneumatic blowing device for generating a gaseous fluid flow, in particular an air flow, which is designed so that a glass pane is blown from below by the gaseous fluid flow, thereby raised and against the first pressing surface of the upper press bending form can be pressed. The blowing device can in particular be designed such that the glass pane fixed on the first pressing surface is pre-bent by the pressure exerted by the gaseous fluid flow in the edge area and / or in the inner area, advantageously at least in the edge area.

As used here and below, the term "fixing" refers to the fixation of a glass pane on the first pressing surface of the first or upper press bending mold, wherein the glass pane can be pressed against the first pressing surface and / or sucked against the first pressing surface. The fixing of a glass pane on the first pressing surface is not necessarily associated with a bending process, but typically leads to at least a slight bending of the plastically deformable glass pane.

The first or upper press bending mold is used to fix a glass pane on the first pressing surface. The first press bending mold is also used to place the glass pane on a lower press bending mold or a prestressing frame or to press the glass pane between the upper press bending mold and the lower press bending mold.

The device for press bending glass panes further comprises a second or lower press bending mold with a pressing surface for placing a glass pane, pressing a glass pane in cooperation with the first press bending mold, and optionally also for transporting a glass pane. For ease of reference, the pressing surface of the second press bending die is referred to as the "second pressing surface". In the working position, the second press surface of the second press bending mold is oriented against the direction of gravity, i.e. upwards.

As used here and below, the terms "upper press bending mold" and "lower press bending mold" refer to two different press bending molds, the upper press bending mold being arranged above the lower press bending mold in the working position for pressing a glass pane. According to the invention, the second press bending mold has a press frame. The press frame is designed in the form of an uninterrupted or interrupted frame. The press frame delimits an (inner) area of the second press bending mold. The press frame of the second press bending mold has a press surface (ie press surface section of the second press surface) which is suitable for bending a glass pane (only) in its edge area. The area of the glass pane in contact with the pressing surface of the press frame is typically a circumferential peripheral (eg strip-shaped) edge area of the glass pane, but the glass pane can also protrude beyond the pressing surface of the press frame. The pressing surface of the press frame is formed, for example, in the form of a strip, for example with a strip width in the range from 3 to 150 mm. It goes without saying that a greater width is advantageous due to a better weight distribution in terms of avoiding undesired markings (changes in the flat surfaces of the glass pane), whereby the generation of markings can be counteracted by pressing the glass pane in the edge area. The frame is typically designed in such a way that a (for example, strip-shaped) circumferential edge region of the glass pane can be press-bent through the pressing surface of the frame. Corresponding to the circumferential edge area of the glass pane, the press frame is also designed "circumferentially". The frame can have one or more interruptions, the circumferential edge area of the glass pane in this case not being press-bendable by the press frame where the frame is interrupted. The press frame is a closed structure, the shape of the press frame being adapted to the surrounding edge area of the glass pane and thus the outer contour of the glass pane. The press frame can also be referred to as "ring-shaped", with the measure that the press frame can have any shape that is adapted to the outer contour of the glass pane and which typically deviates from the circular ring shape.

The second press bending mold enables surface bending by gravity in an inner area of the glass pane surrounded by the edge area and is designed for this purpose in such a way that sagging of the inner area of the glass pane is possible due to gravity in the area of the second press bending mold delimited by the press frame. For this purpose, the second press bending mold can be open, ie it can be provided with a central opening which is delimited by the press frame. Alternatively, the second press bending mold can also be configured over the entire surface as long as the inner region of the glass pane can sag. An open design is preferred with a view to simpler processing of glass panes. With gravity bending, the glass pane is bent by its own weight. The second press-bending mold furthermore has one or more press elements - referred to below as "press inserts" - which are designed to be suitable for press-bending a glass pane. If reference is made to several press inserts in the further description, these statements always refer to the case that the second press bending mold has only a single press insert, unless several press inserts are absolutely necessary.

The press inserts are each arranged at least in sections (i.e. partially) within the area delimited by the press frame. A press insert can be located completely within the area delimited by the press frame. A press insert can, however, also extend with one end or both ends into the press frame (i.e. into a respective interruption of the press frame) and supplement the press frame to form a closed structure that is not broken through.

Both the press frame and the press inserts each have a press surface section for pressing a pane of glass in cooperation with the first press surface of the first press bending mold. The press surface sections of the press frame and the press inserts together form the second press surface of the second press bending mold. The second bending form without press inserts can also be referred to as a press frame (e.g. press ring).

The first press bending mold used for pressing a glass pane has a first pressing surface which is designed to be complementary to the second pressing surface of the second press bending mold. Complementary here means that the first pressing surface of the first press bending mold is designed as a negative mold to the second pressing surface, which is then the positive mold.

The first press-bending mold and the second press-bending mold can be displaced relative to one another in the vertical direction, so that a glass pane can be press-bendable between the two pressing surfaces. As a result, the glass pane is press-bent in the edge area and in an inner area surrounded by the edge area. In addition, the glass pane can be bent in the edge and inner area by gravity when the glass pane rests on the second press bending mold. The term “press bending mold” does not exclude that the glass pane is completely subjected to a gravitational bending on the second press bending mold. In the device according to the invention, a sheet of glass is always press-bent by means of the both press bending forms. For example, a sheet of glass is first placed on the lower press bending mold, followed by pressing between the two press bending molds, or a glass sheet is pressed between the two press bending molds without the glass sheet being first placed on the second press bending mold.

The press inserts each have an elongated shape and are ausgebil det in the form of a strut. The press inserts do not complement each other to form a closed structure and do not form a frame. In particular, the press inserts do not serve to bend a glass pane in the area of a circumferential edge of an opening.

The one or more press inserts are each designed in such a way that an elongated region with an alternating curvature of the glass pane can be press-bent through each press surface section of a press insert. In other words, each press insert alone can produce an area with alternating curvature of the glass pane. Correspondingly, several areas with alternating curvature of the glass pane can be produced by several press inserts. Each area with alternating curvature is produced, according to the arrangement of the press inserts, at least in the inner area of the glass pane, which has no direct contact with the press frame, by the press insert by means of press bending between the two press bending molds and, if necessary, by means of gravity bending on the second press bending mold. By the action of the press inserts on the glass pane, an area with alternating curvature can be produced by a combination of gravity bending and pressing or, alternatively, only by pressing in the inner area and optionally the edge area of the glass pane.

A region of the glass pane with alternating curvature can also be referred to as an "edge" and is to be regarded as a combination or sequence of convex curvature and concave curvature of the glass pane. A convex curvature is a bulge, a concave curvature a depression in the glass pane. At a countersink in the glass pane, the glass pane deepens, for example, against the direction of gravity, ie in the direction of the first press bending mold. At a bulge, the pane of glass is deepened, for example in the direction of gravity, ie in the direction of the lower press-bending mold. The sequence of convex curvature and concave curvature is present transversely to the extent of the elongate region with alternating curvature (edge). Each of the two press bending molds has a pressing surface that comes into contact with the glass pane and acts on it for shaping in order to adapt it to the shape of the pressing surface and thereby bend it. The pressing surface is therefore suitable for influencing the shape of the glass pane. The pressing surface can also be referred to as the contact surface or generally as the "effective surface". The pressing surface defines the shape of the curved glass pane. The pressing surface can be in direct contact with the glass pane. The pressing surface can also, for example, be provided with a fabric which is arranged between the actual pressing surface and the glass pane.

The pressing surfaces generally have a defined geometry, the press bending forms being sufficiently rigid for this purpose. The surrounding press frame and the at least one press insert are shaped, for example, as a cast part. The pressing surfaces are produced, for example, by milling.

The first pressing surface of the first or upper press bending mold is typically designed over the entire surface. A full-surface pressing surface can also be called solid and is in contact with a large part of the glass pane surface at the end of the bending step. The full-surface pressing surface can be equipped with holes or openings through which a suction effect can be exerted on the surface of the glass pane facing the pressing surface.

The second press surface of the second or lower press bending mold is formed by the press frame and the one or more press inserts. A lower press bending mold without press inserts can also be referred to as a press frame. A frame can also only be provided to support a pane of glass (i.e. not for press bending). An example of this is the prestressing frame (see below).

The pressing surface of a press bending mold can be flat, convex and / or concave. A concave shape is understood to mean a shape in which the corners and edges of the glass pane are bent away in the intended contact with the press surface in the direction of the press bending mold. Conversely, a convex shape is understood to mean a shape in which the corners and edges of the glass pane are bent in the intended contact with the pressing surface in the direction of the press-bending form. An essentially concave pressing surface can additionally have convex areas and an essentially convex pressing surface can also have concave areas. The glass sheet is typically transported horizontally through the bending device. In the context of the invention, a lower press bending mold is understood to mean a mold which touches the lower surface of the glass pane (facing the ground) or is assigned to it and acts on it. An upper press bending mold is understood to mean a shape which is assigned to the upper surface of the glass pane (facing away from the ground) and acts on it. The glass pane is blown onto the pressing surface of the upper bending press and / or sucked in by the transport device, or is pressed against the upper bending press with a tool, for example the lower bending press. The upper press bending mold can be installed in a stationary manner or can be lowered to take over or press the glass pane.

Typically, at the beginning of the bending step, only part of the pressing surface is in contact with the glass pane and the glass pane rests against the pressing surface in the course of the bending step. This can take place under the action of gravity, a pressing pressure or a suction effect.

The device for press-bending glass sheets comprises an upper press-bending mold and a lower press-bending mold, between which a glass sheet can be press-bent. The upper press bending mold preferably has a full-surface pressing surface. The lower press bending mold has a pressing surface with a frame-like pressing surface section for the edge area of the glass pane and a pressing surface section provided by at least one press insert for the inner area and optionally the edge area of the glass pane. In an advantageous embodiment, the glass pane is blown against the pressing surface of the upper press bending mold and / or sucked in. The device also includes means to move the lower and upper press bending molds against each other, for example cylinders, servomotors, a chain hoist system or a robot arm, with which the upper press bending mold can be lowered and / or the lower press bending mold can be raised. For example, the first or upper press bending mold is coupled to a movement mechanism by means of which the first press bending mold can be fed to the second or lower press bending mold. However, it is also possible for the second or lower press bending mold to be fed to the first or upper press bending mold.

The device according to the invention for press bending glass panes advantageously enables the production of glass panes with local areas that each have an age have rening curvature. These areas typically have small radii of curvature and / or strong changes in curvature (high curvature gradients) and can advantageously also be located relatively far from the edge of the glass pane (ie in the inner area of the glass pane). This is made possible by one or more press inserts of the second press bending mold, which are each designed to produce an elongated area with alternating curvature (edge). The press inserts are each arranged at least partially within the press frame, that is to say within the region of the second press bending mold which is bounded by the surrounding press frame and in which a gravitational bending of the glass pane is made possible. The use of press inserts thus advantageously enables the production of glass panes with very complex geometries, in which there are strongly curved edges in the interior of the glass pane, with high optical quality.

According to an advantageous embodiment of the device according to the invention for press bending of glass panes, the lower press bending mold has several press inserts, so that several local areas with alternating curvature (edges) can be produced. As already stated, the press inserts do not complement each other to form a (e.g. closed) frame in order to bend a pane of glass in the circumferential edge area of an opening.

According to an advantageous embodiment of the device according to the invention, one or more press inserts are each located completely within the area bounded by the press frame. In this case, edges can only be created in the interior of the glass pane.

According to a further advantageous embodiment of the device according to the invention, one or more press inserts extend, each with one end or with both ends, to the press frame. This advantageously enables an edge to be produced which extends as far as the edge region of the glass pane. It is also possible that one or more press inserts each extend with one end or both ends into a respective interruption of the press frame. In this case, it is particularly advantageous if the pressing surface section (i.e. contour of the pressing surface) of a respective press insert is continuously continued into the pressing surface (i.e. contour of the pressing surface) of the press frame (either through the press insert or the press frame itself) so that an edge can also be continued continuously in the edge area of the glass pane. According to a further advantageous embodiment of the device according to the invention, the press inserts are arranged lying next to one another, in particular lying parallel to one another or inclined to one another. It is particularly advantageous if several press inserts lie next to one another and are arranged symmetrically with respect to an (imaginary) axis of symmetry extending between the press inserts. The axis of symmetry does not intersect the press inserts, but the press inserts are arranged on both sides of the axis of symmetry. In this way, aesthetically particularly appealing edges can be produced in glass panes, which are used, for example, as roof, rear or side windows of a motor vehicle.

For example, the press inserts are arranged in such a way that the edges produced extend in a longitudinal direction (vertical direction) of the glass pane or are inclined for this purpose. For example, the press inserts are arranged in such a way that the edges produced extend in a transverse direction of the glass pane or are inclined to this end. The longitudinal direction of a pane of glass corresponds, for example, to the direction of movement of a vehicle. The transverse direction of the glass pane is the direction perpendicular to it.

According to a further advantageous embodiment of the device according to the invention for press-bending glass panes, the press surface sections of the press inserts are each formed in stages. A stepped design means that a pressing surface section contains a region with an alternating curvature. This enables a particularly simple manufacture of edges in the interior of a pane of glass, which are aesthetically very appealing.

In principle, the press inserts can be designed as desired, as long as it is ensured that the pressing surface section provided by each press insert enables press bending of the glass pane with the first press bending mold to produce an area with alternating curvature of the glass pane (edge). With a view to avoiding optical defects, especially in the interior of the glass pane, it can be advantageous if a press layer has a core with a coating, the coating being more flexible, ie softer, than the core. By this measure it can be achieved in an advantageous manner that the glass pane comes to rest against the second pressing surface, as it were, "softer", as a result of which optical errors occur less frequently. The coating consists of a material that can withstand the high temperatures of press bending. The cover is preferably made from a knitted fabric which contains, for example, steel and glass fibers. Such coatings are known to the person skilled in the art from specialist retailers. According to a further advantageous embodiment of the device according to the invention for press bending glass panes, the bending zone comprises at least one further first or upper press bending mold with a first pressing surface for a glass pane. The further first press bending mold does not necessarily have to be used for pressing a glass pane with the second press bending mold. It is conceivable that the further first press bending mold is only used to fix a glass pane on its first press surface and place it on the second press bending mold.

The at least one further first press-bending mold and the second press-bending mold can be moved relative to one another in the vertical direction, so that a pane of glass can be placed and / or press-bendable on the second press-bending mold. Preferably, the second press-bending mold can be moved laterally (i.e. with at least one horizontal movement component) between the working positions associated with the two first press-bending molds relative to the first press-bending molds. Advantageously, the lower press bending mold can be moved reciprocally and translationally (1-dimensional) in a horizontal plane. Typically, the working position of the second press bending form assigned to a respective first press bending form is located in the vertical direction (e.g. directly) below the first press bending form.

The device according to the invention also advantageously has a preheating zone or preheating chamber with a heating device for heating glass panes to a bending temperature, as well as a transport mechanism, in particular of the roller bed type, for transporting glass panes from the preheating zone to the bending zone or bending chamber, in particular to a removal position (e.g. directly) below the first press bending form. The roller bed is advantageously designed so that individual glass panes can be transported to the removal position one after the other. The removal position can in particular correspond to an end section of the roller bed.

The device according to the invention also advantageously has a thermal prestressing zone with a cooling device for thermal prestressing of a glass pane, a prestressing frame (eg prestressing ring) being provided for transporting a glass pane. The prestressing frame is preferably laterally movable between two working positions relative to the first press bending mold in a reciprocal manner (ie with at least one horizontal movement component). The prestressing frame can advantageously be moved reciprocally and translationally (1-dimensional) in the horizontal plane. The thermal toughening (tempering) deliberately creates a temperature difference between a surface zone and a core zone of the glass pane in order to increase the breaking strength of the glass pane. The pretensioning of the glass pane is advantageously generated by means of a device for blowing a gaseous fluid, preferably air, onto the glass pane. Preferably, the two surfaces of a pane of glass are acted upon by a cooling air stream at the same time.

The prestressing frame for transporting a glass pane from the bending zone to the prestressing zone advantageously has a frame surface which is suitably designed for an edge bending in the edge region of the glass pane. In addition, it is advantageous if the prestressing frame is designed to be suitable for surface bending by gravity in the inner region of the glass pane. The prestressing frame has only one frame, but no bending elements in an inner area delimited by the frame. In particular, the prestressing frame has no press inserts.

The device according to the invention for press-bending glass panes advantageously comprises at least one, in particular several, heating means for heating the glass pane to be bent. The heating means are preferably suitable for heating the glass pane essentially uniformly, as is also customary with conventional bending devices. Uniform heating is understood to mean heating in which the entire main surfaces of the glass pane are exposed to essentially the same temperature without a pronounced temperature profile being generated. However, it would also be possible to heat the glass panes more intensely where a particularly strong curvature is generated. The glass pane to be bent is typically flat in its initial state.

The heating means preferably act essentially uniformly and over the entire area at least on the two main surfaces of the glass pane, in particular by means of thermal radiation or convection. The heating means are in particular those that are also used in conventional bending devices. The heating means can for example be designed in the manner of a convection oven, with heated air being fed to a heating chamber, whereby the heating of the glass pane in the heating chamber is achieved. Typically, the heating means are designed as radiant heaters. At least one radiant heater, in particular a plurality of radiant heaters, is preferably assigned to and facing a main surface of the glass pane, and likewise at least one radiant heater, in particular several Radiant heater, the other main surface. The main surfaces are subjected to thermal radiation by the radiant heaters that are assigned to them and facing them, whereby the heating of the glass pane is achieved. The glass pane is advantageously transported horizontally lying on a transport device into a heating chamber, where the radiant heaters are arranged below and above the transport device in order to act on the two main surfaces.

The device according to the invention is preferably equipped with means of transport for transporting the glass pane. The transport means serve to transport a pane of glass to be bent to the heating means and to the press bending molds. In a preferred embodiment, the transport means are designed as a roller conveyor system or belt conveyor system on which the glass sheet rests directly and is moved horizontally. This enables particularly short cycle times to be achieved. Alternatively, the glass pane can also be mounted on a transport form, in particular a form with a frame-like support surface, which on its part is moved, for example, by means of a roller, belt or rail conveyor system.

In a preferred embodiment, the transport means are designed as a continuous conveyor system, particularly preferably as a continuous roller conveyor system. In such a conveyor system, the glass sheet is continuously moved through the device to the Pressbiegefor men without lingering in one place for a long time. The glass sheet is fed to the heating means and the press bending molds in a continuous movement by means of the continuous conveyor system. The glass pane is heated by means of the heating means during the continuous movement. The heating means, in particular radiant heaters, are preferably arranged above and below the rollers of the roller conveyor system and directed towards the roller conveyor system, so that they act simultaneously on both main surfaces of the glass pane, whereby efficient heating of the glass pane is achieved. Continuous roller conveyor systems are particularly common when bending relatively inexpensive single-pane safety glass, for example for side, roof or rear windows of vehicles. The conveying speed of the continuous conveying system is preferably from 100 mm / s to 600 mm / s. In principle, the invention can also be used for non-continuous bending devices in which the movement of the glass pane is interrupted and the glass pane remains in one place for a long time, in particular for heating with the heating means, or is moved back and forth. Instead of a continuous roller conveyor Systems, a continuous belt conveyor system can also be used. The conveyor system can also be designed completely or in sections as an air cushion conveyor system.

The glass pane is preferably heated to a temperature of 500 ° C. to 700 ° C., particularly preferably from 550 ° C. to 670 ° C., for example about 650 ° C., by the heating means. This corresponds to typical bending temperatures for panes of glass, especially for those made of soda-lime glass.

In one embodiment of the invention, the heating means are arranged in a heating chamber and the press bending dies are arranged in a bending chamber. The heating chamber and bending chamber are separated from each other and (largely) closed off from the environment by a chamber wall. The means of transport run through the heating chamber and lead into or through the bending chamber. The glass pane is transported into and out of the heating chamber with the transport means. The inlet and outlet of the heating chamber are preferably located on opposite sides, so that the glass pane is transported through the heating chamber by the means of transport. The glass pane is then transported into the bending chamber and transferred to the first press bending mold. After the press bending, the glass pane can be placed back on the transport means in order to transport it out of the bending chamber or otherwise transported out of the bending chamber. The heating and bending chambers have openings for the transport of the glass pane. At least in the case of the heating chamber, the openings are preferably designed in the form of slits with the lowest possible height in order to prevent the chamber from cooling down too much. The openings can optionally be closed with a sliding door or curtain system if no pane of glass is being transported through the opening.

In a further embodiment of the invention, the heating means and the press bending molds are arranged in a common chamber, which can be characterized as a combined heating and bending chamber. The combined heating and bending chamber is (largely) closed off from the surroundings by a chamber wall. The means of transport lead into or pass through the heating and bending chamber. The glass pane is transported into the heating and bending chamber with the transport means. The glass pane is first exposed to the action of the heating means and then transferred to the press bending molds. After the press bending, the glass pane can be put back on the means of transport. be placed in order to transport them out of the heating and bending chamber, or otherwise transported out of the heating and bending chamber. The heating and bending chamber has openings for the transport of the glass pane. The openings can optionally be closed with a sliding door or curtain system if no pane of glass is being transported through the opening.

In a particularly preferred embodiment, the transport means are designed as a continuous roller conveyor system. The heating means are designed as radiant heaters, which are arranged in a heating chamber or a combined heating and bending chamber above and below the Rol len. The glass pane is continuously moved between the radiant heaters by the roller conveyor system and fed to an upper press bending mold with a preferably full-area pressing surface, which is either located in its own bending chamber or in the combined heating and bending chamber above the rollers. If the glass pane is positioned underneath the upper bending press, it is blown onto the upper bending press (by an air stream from below) and / or sucked in. Then a lower die is moved under the upper die with the glass sheet, and the glass sheet is pressed between the upper die and the lower die to bend it into the desired shape. Then the lower press bending mold is removed again while the glass pane is still fixed to the upper press bending mold by blowing and / or suction. Now a prestressing frame is moved under the upper press bending form with the glass pane and the glass pane is transferred to the prestressing frame by switching off the blowing or suction effect. The glass pane is removed from the bending chamber or the combined heating and bending chamber on the prestressing frame and fed to a prestressing device, where it is subjected to a stream of air and thereby cooled and thermally prestressed.

In a preferred embodiment, the glass panes to be bent are made of soda-lime glass, as is customary for window panes. The glass panes to be bent can also contain other types of glass such as borosilicate glass or quartz glass. The thickness of the glass pane is typically from 0.2 mm to 10 mm, preferably from 0.5 mm to 5 mm. The curved glass pane is provided in a preferred embodiment as a window pane of a vehicle, in particular special as a side window, roof window or rear window of a motor vehicle. The device according to the invention for press bending glass panes is used in particular to carry out the method described below. In this respect, reference is made in full to the above statements.

The method according to the invention comprises a step in which a glass pane heated to the bending temperature is provided. The method may include a step in which the glass sheet is heated substantially uniformly by heating means. The glass pane is brought to at least its softening temperature at which the glass becomes malleable. However, it would also be possible to heat the glass pane more intensely where a particularly strong curvature is to be generated.

The method according to the invention comprises a further step in which the glass pane heated to the bending temperature is pressed between the first pressing surface of a first press bending mold and the second pressing surface of a second press bending mold. With regard to the design of the two press bending forms, reference is made to the above statements. Here, the glass pane is pressed between the first pressing surface and the second pressing surface, the two press bending dies being moved relative to one another in the vertical direction. The second press bending mold comprises a press frame and one or more press inserts, the press inserts each being designed in the form of a strut and being arranged at least partially within an area delimited by the press frame. The press frame and the one or more press inserts each have a press surface section which together form the second press surface, the second press surface being designed to be complementary to the first press surface, with an area with alternating curvature of the glass pane through each press surface section of the one or more press inserts (Edge) is press-bent.

According to one embodiment of the method according to the invention, it comprises a further step in which the glass pane is fixed on the first pressing surface of the first press bending mold. The glass pane is advantageously fixed on the first pressing surface of the first press bending mold by lifting the glass pane by blowing a gaseous fluid on it and pressing it against the first pressing surface of the first press bending mold. Alternatively and preferably in addition, the glass pane is fixed by suction on the first pressing surface of the first press bending mold. Depending on the pressure with which the glass pane is pressed against the first pressing surface of the first press bending mold, the glass pane can an edge pre-bend in the edge area and / or a surface pre-bend in the interior area.

The glass pane fixed on the first press-bending mold can be pressed between the first press-bending mold and the second press-bending mold without being previously deposited on the second press-bending mold.

According to a particularly advantageous embodiment of the method according to the invention, it sums up a further step in which the glass pane is placed between the two press bending molds on the second press bending mold prior to pressing, the glass sheet being laid down is pre-bent solely by gravity. For this purpose, the glass pane is fixed to the first pressing surface of the first press bending mold or a further first press bending mold and then placed on the second press bending mold by the first press bending mold. The glass pane is then pressed between the first press bending mold and the second press bending mold. By first placing it on the second press bending mold, the glass pane is pre-bent by gravity, followed by bending by pressing, so that the glass pane is bent gradually and gently, which reduces the likelihood of optical defects and further improves the optical quality of the glass pane can.

According to an advantageous embodiment of the method according to the invention, while the glass pane is fixed on the first pressing surface of the first press bending mold, the second press bending mold is transported to a working position assigned to the first press bending mold. If two first press bending molds are used, it can be advantageous if the glass pane on the second press bending mold is transported from one first press bending mold to the other first press bending mold, the glass sheet being pre-bent during transport. It is also possible, however, for the second press-bending mold to remain stationary (unchanged in location) with the glass pane placed thereon and for the first two press-bending molds to be moved laterally to the second press-bending mold.

According to a further embodiment of the method according to the invention, it comprises a further step in which the glass pane is transported on a prestressing frame to a cooling device for thermal prestressing of the glass pane. Preferably, while the glass pane is fixed on the first pressing surface of the first press bending mold, the prestressing frame is ported to a working position assigned to the first press bending mold. The prestressing frame is advantageously moved between a working position assigned to the first press bending mold, which is preferably (e.g. directly) below the first press bending mold, and a further working position for thermal prestressing of the glass pane laterally relative to the first press bending mold. Preferably, the leader frame is reciprocally (bidirectional) translationally (1-dimensional) moved in a horizontal plane between tween the two working positions.

The pressing of the glass pane between the two press bending molds can give the glass pane a final or quasi-final shape. Typically, but not necessarily, the shape of the glass pane on the prestressing frame will change (usually only slightly). The glass pane is then given its final shape on the prestressing frame.

The glass sheet is preferably transported by a transport mechanism, in particular of the roller bed type, to a removal position which is preferably (e.g. directly) below the first press bending mold. The glass pane is preferably heated to bending temperature on the roller bed.

The invention is particularly suitable for press bending of glass panes with complex curvatures (edges), especially in the interior of the glass pane, which can only be produced with difficulty using conventional methods. Such complex curvatures can, for example, be characterized by areas with particularly small radii of curvature or with strong changes in curvature.

The invention also extends to the use of the device according to the invention and the method according to the invention for setting glass panes for Fortbewe supply means for traffic in the country, in the air or on water, in particular in motor vehicles, and in particular for side windows, roof panes and stain panes in Motor vehicles.

The various embodiments of the invention can be implemented individually or in any combination. In particular, the features mentioned above and to be explained below can be used not only in the specified combinations, but also in other combinations or on their own, without departing from the scope of the present invention. The invention will now be explained in more detail on the basis of exemplary embodiments, reference being made to the accompanying figures. It shows in a simplified, not to scale representation:

1 shows a cross section through an embodiment of the device according to the invention during a first part of the method according to the invention,

FIG. 2 shows a cross section through the device from FIG. 1 during a second part of the method according to the invention which follows,

Fig. 3 shows an embodiment of the lower press bending mold in a perspective view,

FIG. 4 shows a cross section through the lower press bending mold from FIG. 3,

5 shows a cross section through a glass pane bent according to the invention,

Fig. 6 is a flow chart of the method according to the invention for Fierstellen a glass pane.

Let us first consider FIG. 1, in which a device, denoted overall by the reference number 1, for press-bending glass panes is illustrated in a schematic manner at later points in time. The device 1 comprises a heating chamber 2, in which heating means 3 are arranged, which are designed here, for example, as radiant heaters. The device 1 also comprises a bending chamber 4 in which an upper press bending mold 5 is installed. The upper bending press mold 5 has a full-surface, convex pressing surface 6, here referred to as the upper pressing surface 6. The upper pressing surface 6 is arranged on the underside of the upper bending press mold 5 and is directed downwards in the working position.

The device 1 also comprises a roller conveyor system 7 which runs through the heating chamber 2 and into the bending chamber 4. In the schematic illustration of FIG. 1, the heating chamber 2 is at a distance from the bending chamber 4, it being understood that the heating chamber 2 can directly adjoin the bending chamber 4. One in the initial state flat glass sheet 8 is positioned directly on the roller conveyor system 7 and moved in a continuous movement (coming from the left in the figure) into the heating chamber 2, through it and then into the bending chamber 4. In the Heizkam mer 2, the glass pane 8 is heated by the heating means 3 essentially evenly, for example to a temperature of about 650 ° C (Fig. 1a). The heating means 3 are arranged in the heating chamber 2 above and below the roller conveyor system 7 in order to irradiate both surfaces of the glass pane 8 simultaneously.

The device 1 is designed for a continuous bending process. You can already transport the next glass sheet 8 to be bent into the heating chamber when the previous glass sheet 8 has arrived in the bending chamber 4, but this is not provided for the sake of simplicity. The distance between successive glass panes 8 depends in particular on the cycle time of the bending in the bending chamber 4.

In Figure 1 a, a situation is shown in which a pane of glass 8 on the roller conveyor system 7 in the heating chamber 2 is. In FIG. 1 b, the glass pane 8 heated to the bending temperature is transported on the roller conveyor system 7 from the heating chamber 2 into the bending chamber 4. In FIG. 1c, the glass pane 8 heated to the bending temperature is located on the roller conveyor system 7 in the bending chamber 4

FIG. 2 shows the device 1 from FIG. 1 during a second part of the method, in continuation of FIG. 1, in each case at a later point in time. The glass pane 8 has been blown onto the upper press bending mold 5 by an air stream (not shown) passing through the rollers of the roller conveyor system 7 from below, which is supported by a suction effect through openings in the upper press surface 6 of the upper press bending mold 5 (Fig. 2a ).

Now, for example by means of a chain hoist system or movable cylinder, a lower press bending mold 9 is moved under the upper press bending mold 5 and the glass pane 8 is pressed between the two press bending molds 5, 9 (FIG. 2b). For this purpose, the upper press bending mold 5 is lowered onto the lower press bending mold 9 with the glass pane 8. The lower press bending mold 9 has a concave (second) press surface 10 which is complementary to the convex (first) press surface 6 of the upper press bending mold 5. By pressing between the two press bending dies 5, 9, the glass pane 8 is bent into the desired shape. Then the lower press bending mold 9 is removed again and a Vorspannrah men 11 with a frame-like support surface is moved under the glass pane 8. By interrupting the blowing and suction effect, the glass pane 8 is released from the upper press bending mold 5 and placed on the prestressing frame 11 (FIG. 2c). The glass sheet 8 is then removed with the prestressing frame 11 from the bending chamber and fed to a prestressing device (not shown), where it is thermally prestressed by rapid cooling by means of a strong gas flow, in particular an air flow.

FIG. 3 shows an exemplary embodiment of the lower press bending mold 9 of the device 1 according to the invention in a perspective view from above. The lower press bending mold 9 comprises a closed (uninterrupted) press frame 12 which defines an open area (interior) 15. Two press inserts (pads) 13 are arranged inside the press frame 12, i.e. in the area 15 bounded by the press frame 12. The press inserts 13 each have an elongated shape and are designed as struts. The two press inserts 13 are arranged side by side, in parallel. The (second) press surface 10 of the lower press bending mold 9 is composed of the press surface section 14 of the press frame 12 and the press surface sections 14 'of the two press inserts 13 together.

In the exemplary embodiment of FIG. 3, the two press inserts 13 do not extend as far as the press frame 12, but it would equally be possible that they each extend with one end or with both ends as far as the press frame 12. The press inserts 13 are here, for example, arranged completely within the area 15 delimited by the press frame 12. It would be possible for the press frame 12 to have one or more openings. One or more press inserts 13 could each extend with one end or at the ends into an opening in the press frame 12, so that they each cut with a section in the area 15 delimited by the press frame 12 and with one end section or two end sections in the area of the press frame 12 are arranged. Instead of two press inserts 13, a larger or smaller number of press inserts 13 could be seen before. In this exemplary embodiment, the two press inserts 13 are arranged symmetrically with respect to an (imaginary) line of symmetry. The two press inserts 13 extend here, for example, in the longitudinal direction of the glass sheet 8, whereby they could equally be inclined with respect to the longitudinal direction, or each could extend in the transverse direction of the glass sheet 8 or could be inclined with respect to the transverse direction. FIG. 4 shows the upper press bending mold 5 and the lower press bending mold 9 in a press position in which the (first) press surface 6 of the upper press bending mold 5 and the (second) press surface 10 of the lower press bending mold 9 bear against one another. During a pressing process, the glass pane 8 is located between the two pressing surfaces 6, 10, which is not shown in FIG. It can be clearly seen that the (first) press surface 6 of the upper press bending mold 5 is designed complementary to the (second) press surface 10 of the lower press bending mold 9, in particular in the area of the press inserts 13. The press surface section 14 'of the press inserts 13 is each stepped 16 provided, which extends along the direction of extension of the Presseinla conditions 13. In an optional configuration in which the press inserts 13 each extend as far as the press frame 12, it would be conceivable that the press surface section 14 of the press frame 12 has the same step 16, ie the shape of the press surface sections 14 'merges continuously into the press surface section 14. Alternatively, the press inserts 13 could extend into the press frame 12.

FIG. 5 shows, by way of example, a glass pane 8 with a complex curvature which can be produced with the device according to the invention and the method according to the invention. The glass pane 8 has, in an inner area 18 delimited by the edge area 19, two areas B which are strongly curved and are also characterized by a strong change in curvature, i.e. alternating curvature. Between the two areas B there is a depression 17 of the glass pane 8. Outside of the areas B, the glass pane 8 is less curved with radii of curvature, as are customary for vehicle glazing. Since the areas B extend over the see-through area of the glass pane 8 and are therefore not contacted by the press frame 12 of the lower press bending mold 9, the complex shape can only be produced with difficulty using conventional methods. With a full-area lower press bending mold 9, the shape could indeed be realized, but this would significantly reduce the optical quality of the glass pane 8. The indentation 17 can be formed in the inner region 18 of the glass pane 8, but can also extend into the edge region 19.

In FIG. 6, the successive steps of the method for lowering the glass pane 8 are illustrated with the aid of a flow chart. Here, in a first step I, a glass pane 8 heated to the bending temperature is provided. In a second step II, the glass pane 8 is fixed against the (first) pressing surface 6 of the first press bending mold 5, wherein if necessary, an edge pre-bending in the edge region 19 and, if necessary, a surface pre-bending in the inner region 18 of the glass pane 8 takes place. In a third step III, the glass pane 8 is pressed against the (second) pressing surface 10 of the lower press bending mold 9, as a result of which the indentation 17 is produced.

In an optional further step, the glass pane 8 is placed on the prestressing frame 11 and thermally prestressed, it being possible for a gravitational bending to take place on the transport to a prestressing chamber. The glass sheet 8 is thus given its final shape only on the Vorspannrah men 11.

In the exemplary embodiments of the method according to the invention illustrated with reference to the figures, the glass sheet 8 is bent by pressing the glass sheet 8 between the first press bending mold 5 and the second press bending mold 9, in which the indentation 17 is produced. It would also be possible to first place the glass pane 8 on the lower press bending mold 9 so that it is subjected to a gravitational bending, followed by pressing between the upper press bending mold 5 and the lower press bending mold 9 be improved. From the foregoing it follows that the invention provides a method and a device for setting glass panes, by means of which a simple, reliable and inexpensive setting of glass panes with short cycle times is made possible. Glass panes with strongly curved areas in the interior and edge area with alternating curvature (edges) can be produced with high quality requirements. In addition, throughput can be increased for complex glass designs.

List of reference symbols

1 device

2 heating chamber 3 heating means

4 bending chamber

5 first press bending form

6 first pressing surface

7 roller conveyor system 8 glass pane

9 second press bending mold

10 second pressing surface

11 Prestressing frame

12 press frame 13 press insert

14.14 'pressing surface section

15 area

16 step

17 sinking

18 Indoors

19 border area

Claims

Claims 1 . Device (1) for press bending glass panes (8), comprising: - a first press bending mold (5) with a first pressing surface (6), - A second press bending mold (9) with a second press surface (10) which comprises a press frame (12) and one or more press inserts (13), the press inserts (13) each being in the form of a strut and at least partially within one of the Press frame (12) delimited area (15) are angeord net, the press frame (12) and the one or more press inserts (13) each having a press surface section (14, 14 ') which together form the second press surface (10), wherein the second pressing surface (10) is designed to be complementary to the first pressing surface (6), the two press bending dies (5, 9) being movable relative to one another in the vertical direction so that a glass pane (8) between the two pressing surfaces (6, 10) can be press bendable and wherein the one or more press inserts (13) are each designed in such a way that an area (B) with an alternating curvature of the glass pane (8) can be press-bent through each press surface section (14 '). 2. Device (1) according to claim 1, in which a plurality of press inserts (13) lying next to one another, in particular lying parallel next to one another or set at an angle to one another, are arranged. 3. Device (1) according to claim 2, in which a plurality of press inserts (13) are arranged next to one another and symmetrically with respect to an axis of symmetry extending between the press inserts. 4. Device (1) according to one of claims 1 to 3, in which one or more press inserts (13) each with one end or with both ends extend to the press frame (12) and optionally with one end or both ends in a respective opening of the press frame (12) extend into it. 5. The device (1) according to claim 4, wherein the pressing surface sections (14 ') of the press inserts (13) are each designed so that they merge continuously into the pressing surface section (14) of the press frame (12). 6. Device (1) according to one of claims 1 to 5, in which the pressing surface sections (14 ') of one or more press inserts (13) are each stepped. 7. Device (1) according to one of claims 1 to 6, which comprises a pre-tensioning frame (11) for thermal toughening of a pane of glass (8), wherein the prestressing frame (11) relative to the first press bending mold (5) is laterally movable. 8. Device (1) according to one of claims 1 to 7, in which at least one further first press bending mold is provided, wherein the further first press bending mold and the second press bending mold (9) are movable relative to one another in the vertical direction, so that a glass pane ( 8) can be placed and / or press bendable on the second press bending mold (9). 9. A method for press bending of glass panes (8), in particular by feasible in a device (1) according to one of claims 1 to 8, with the following steps: - Providing a glass pane (8) heated to the bending temperature, - Press bending the glass sheet (8) between a first press surface (6) of a first press bending mold (5) and a second press surface (10) of a second press bending mold (9), the two press bending molds (5, 9) relative in the vertical direction are moved to each other, wherein the second press bending mold (9) comprises a press frame (12) and one or more press inserts (13), the press inserts (13) each in the form of a strut and at least partially within one of the press frame (12) delimited area (15), the press frame (12) and the one or more press inserts (13) each having a press surface section (14, 14 ') which together form the second press surface (10), the second press surface (10 ) is designed complementary to the first pressing surface (6), with an area (B) with alternating curvature of the glass pane (8) being press-bent through each pressing surface section (14 ') of the one or more press inserts (13) . 10. The method according to claim 9, in which the glass sheet (8) is placed on the second press bending mold (9) between the two press bending dies (5, 9) prior to pressing, the placed glass sheet (8) being pre-bent by gravity . 11. The method according to claim 10, wherein the glass sheet (8) is set on the first pressing surface (6) of the first press bending form (5) before being placed on the second press bending mold (9). 12. The method according to claim 11, in which, while the glass pane (8) is fixed on the first pressing surface (6) of the first press bending mold (5), the second press bending mold (9) is transported to a working position assigned to the first press bending mold (5) . 13. The method according to any one of claims 9 to 12, in which the glass pane (8) after pressing is placed on a prestressing frame (11) and thermally prestressed. 14. The method according to claim 13, in which, while the glass sheet (8) on the first pressing surface (6) of the first press bending mold (5) is fixed, the front clamping frame (11) is transported to one of the first press bending mold (5) associated working position will. 15. Use of the device according to the invention (1) according to one of claims 1 to 9 and of the method according to the invention according to one of claims 10 to 14 for the production of glass panes for means of transport for traffic on land, in the air or on water, in particular in motor vehicles, and in particular for roof, rear and side windows in motor vehicles.