METHOD AND DEVICE FOR BENDING SHEETS

Abstract

A method for bending sheets, in which a sheet is fixed in a bending chamber on a contact surface of a mold and is placed by the mold onto a frame, wherein the mold is introduced into the bending chamber before the fixing of the sheet in the bending chamber, without the fixed sheet, and is removed from the bending chamber after the placing of the sheet onto the frame, without the fixed sheet.

Claims

1. A method for bending sheets, comprising: fixing a sheet is fixed in a bending chamber on a contact surface of a transportable mold; and placing the sheet by the transportable mold onto a frame, wherein the transportable mold is introduced into the bending chamber before the fixing of the sheet in the bending chamber without the sheet fixed on the transportable mold and is removed from the bending chamber after the placing of the sheet onto the frame without the sheet fixed on the transportable mold.

2. The method according to claim 1, which comprises the following steps: providing the sheet in the bending chamber, fixing the sheet on a contact surface of a first mold within the bending chamber, positioning a press frame in the bending chamber, placing the sheet on the press frame, pressing the sheet between a contact surface of a second mold and the press frame, fixing the sheet on the contact surface of the second mold, positioning a tempering frame in the bending chamber, placing the sheet on the tempering frame, transporting the sheet on the tempering frame to a cooling device for thermal tempering of the sheet, wherein i) the first mold is introduced into the bending chamber before the fixing of the sheet on its contact surface without the sheet fixed on the first mold and is removed from the bending chamber after the placing of the sheet on the press frame without the sheet fixed on the first mold, or ii) the second mold is introduced into the bending chamber before the fixing of the sheet on its contact surface without the sheet fixed on the second mold and is removed from the bending chamber after the placing of the sheet on the tempering frame without the sheet fixed on the second mold.

3. The method according to claim 2, wherein the press frame is not moved after the placing of the sheet on the press frame and the pressing of the sheet by the second mold.

4. The method according to claim 2, wherein the sheet in the fixed state on the first mold and/or the second mold is moved only vertically.

5. The method according to claim 2, wherein the sheet is pressed between the contact surface of the first mold and the press frame.

6. The method according to claim 2, which comprises steps i), steps ii), or step iii): Steps i) first edge pre-bending of the sheet in an edge region by resting the sheet on the press frame and, optionally, by pressing the sheet between the contact surface of the first mold and the press frame, second edge pre-bending of the sheet in the edge region by pressing the sheet between the second mold and the press frame, edge final bending of the sheet in the edge region by resting the sheet on the tempering frame, Steps ii) edge pre-bending of the sheet in an edge region by resting the sheet on the press frame and, optionally, by pressing the sheet between the contact surface of the first mold and the press frame, edge final bending of the sheet in the edge region by pressing the sheet between the second mold and the press frame, Step iii) edge final bending of the sheet in an edge region by pressing the sheet between the first mold and the press frame.

7. The method according to claim 2, wherein the sheet resting on the press frame resting sheet is subjected to surface pre-bending by gravity in an inner region surrounded by an edge region.

8. The method according to claim 2, wherein the sheet resting on the tempering frame is subjected to surface final bending by gravity in an inner region of the sheet surrounded by an edge region.

9. The method according to claim 2, wherein, before the placing of the sheet on the press frame, the press frame is introduced into the bending chamber; and after the fixing of the sheet on the contact surface of the second mold, the press frame is removed from the bending chamber.

10. A device for bending sheets for carrying out the method according to claim 1, comprising: a bending chamber that is adapted to be heated to a temperature suitable for bending sheets, at least one stationary mold with a contact surface for fixing a sheet, which at least one stationary mold is permanently arranged in the bending chamber during a period of time in which one and the same sheet is situated in the bending chamber, at least one transportable mold with a contact surface for fixing a sheet, which at least one transportable mold is at times arranged outside the bending chamber during a period of time in which one and the same sheet is situated in the bending chamber, wherein the at least one transportable mold is fastened on a movable mold carrier and is adapted to be introduced into the bending chamber and is adapted to be removed from the bending chamber by moving the movable mold carrier, wherein the at least one transportable mold serves for being introduced into the bending chamber without a sheet fixed on the at least one transportable mold and for being removed from the bending chamber without a sheet fixed on the at least one transportable mold.

11. The device according to claim 10, wherein the movable mold carrier is mounted on a mold carrier module arranged outside the bending chamber.

12. The device according to claim 11, wherein the mold carrier module has a heatable mold carrier module cavity for receiving the transportable mold.

13. The device according to claim 12, wherein a mold carrier movement mechanism for moving the mold carrier is arranged at least partially outside the heatable mold carrier module cavity and/or which has a cooling device for cooling the mold carrier.

14. The device according to claim 10, which comprises: a press frame for pressing a sheet, wherein the molds and the press frame are movable vertically relative to one another such that a sheet is pressable between a respective contact surface of the molds and a press surface of the press frame, a tempering zone with a cooling device for thermal tempering of a sheet, a tempering frame for transporting a sheet from the bending chamber to the tempering zone.

15. The device according to claim 10, comprising: a pneumatic suction/blowing device associated with each of the molds for fixing a sheet on the contact surface by suction and/or for removing a sheet fixed on the contact surface by blowing, and/or a pneumatic blowing device for lifting and pressing a sheet against the contact surface of a mold by blowing.

16. The device according to claim 11, wherein the mold carrier module is adapted to be delivered to the bending chamber.

Description

[0065] The invention is explained in detail using exemplary embodiments and referring to the accompanying figures. They depict, in simplified, not-to-scale representation:

[0066] FIG. 1 a schematic representation of an exemplary embodiment of the device according to the invention for bending sheets in plan view;

[0067] FIG. 2-3 various sectional views of the device of FIG. 1 along section plane A-A;

[0068] FIG. 4 a sectional view of the device of FIG. 1 along section plane B-B;

[0069] FIG. 5-20 various sectional views of the device of FIG. 1 along section plane B-B to illustrate the method according to the invention;

[0070] FIG. 21A-21B schematic representations to illustrate the pressing of a sheet between a mold and the press frame;

[0071] FIG. 22 a flow chart of an exemplary embodiment of the method according to the invention for producing a sheet.

[0072] Considering first, FIGS. 1 to 4. FIG. 1 depicts, based on a schematic representation in plan view, essential components of an exemplary embodiment of the device for bending sheets designated as a whole with reference number 1. FIGS. 2 and 3 depict a sectional representation of the device 1 along section plane A-A; FIG. 4 depicts a sectional representation along section plane B-B.

[0073] As depicted in FIG. 1, the device 1 comprises a bending chamber 2 for bending (glass) sheets 52, a preheating zone 3 arranged to the side of the bending chamber 2 with a (preheating zone) heating device 33 (not shown in FIG. 1) for heating the sheets to bending temperature, and a tempering zone 4 also arranged to the side of the bending chamber 2 for cooling or tempering bent sheets. The preheating zone 3 and the tempering zone 4 are arranged, viewed from above, at an angle of 90° on the bending chamber 2 and are functionally coupled therewith, with the preheating zone 3 and the tempering zone 4 designed as spatially separate regions of the device 1.

[0074] Arranged on the bending chamber 2 opposite the preheating zone 3 is a modular delivery chamber for a transportable mold 7, referred to in the following as “mold carrier module 5”. Arranged on the bending chamber 2 opposite the tempering zone 4 is a modular delivery chamber for a press frame 8 (not shown in FIG. 1), referred to in the following as “press frame module 6”. The preheating zone 3, the tempering zone 4, the mold carrier module 5, and the press frame module 6 are arranged on four sides of the bending chamber 2 and functionally coupled with the bending chamber 2.

[0075] FIG. 1 depicts the mold carrier module 5 in two spatially different positions. In a first position, the mold carrier module 5 is arranged on the bending chamber 2 and functionally coupled therewith. In a second position (to the right of the first position in FIG. 1), the mold carrier module 5 is spatially separated from the bending chamber 2 and not functionally coupled with the bending chamber 2. Similarly to the mold carrier module 5, the press frame module 6 can be brought into a position spatially separated from the bending chamber 2 (not shown in FIG. 1).

[0076] FIG. 2 (section plane A-A of FIG. 1) depicts in more detail the bending chamber 2, the press frame module 6, and the tempering zone 4, which are arranged opposite one another on the bending chamber 2. Accordingly, the bending chamber 2 comprises an insulating bending chamber wall 9, which delimits a cavity of the bending chamber 2, referred to in the following as bending chamber cavity 10, from the external environment. Thus, the bending chamber cavity 10 can be heated to and maintained at a temperature (bending temperature) suitable for the bending operation of the sheets. For heating the bending chamber cavity 10, the bending chamber 2 has a heating device (not shown). Situated in the bending chamber cavity 10 is a stationary mold 11, which remains permanently within the bending chamber 2 for processing sheets, i.e., is not introduced into the bending chamber 2 and/or removed from the bending chamber 2 during the period of time while one and the same sheet is processed in the device 1.

[0077] The stationary mold 11 has a holder 12 which can be displaced at least vertically relative to the bending chamber wall 9 by a holder movement mechanism 14 (not shown in detail). It is also possible for the holder 12 to be displaced with at least one horizontal movement component. The stationary mold 11 is detachably mounted at the lower end of the holder 12. The stationary mold 11 has a downward directed, convex contact surface 15 for the areal contact of a sheet 52. With appropriate contact pressure, the sheet 52 can be bent on the respective contact surface 15. The contact surface 15 has an end or edge outer surface section 16 and an inner surface section 17 with surface contours (surface shapes) different from one another, with the inner surface section 17 being completely surrounded (bordered) by the outer surface section 16.

[0078] The stationary mold 11 includes a combined suction/blowing device 18 (not shown in detail) for sucking a sheet 52 against the contact surface 15 or removing a sheet 52 fixed on the contact surface 15. For this, the contact surface 15 can, for example, be provided with evenly distributed holes (not shown) and/or an apron at the edge. A sheet 52 can be drawn against the contact surface 15 by a negative pressure generated in the holes or the edge apron. In a corresponding manner, the sheet 52 can be removed from the contact surface 15 when a positive pressure is generated in the holes.

[0079] The bending chamber 2 also has a blowing device 19 (not shown in detail), by which a flowing gaseous fluid, e.g., an air flow 55, can be generated vertically in order to lift a sheet 52 against gravity and, in particular, to press it against the contact surface 15 of the (lowered) stationary mold 11.

[0080] Situated to the side of the bending chamber 2 is the tempering zone 4 for tempering bent sheets. The tempering zone 4 has two so-called “tempering boxes” 20, arranged offset from one another vertically. By means of the two tempering boxes 20, an air flow for the air cooling of a sheet 52 situated between the two tempering boxes 20 can be generated in order to temper the sheet 52.

[0081] For the resting transport of a sheet 52 from the bending chamber 2 into the tempering zone 4, a tempering frame 21 is provided, which is situated below the stationary mold 11 in FIG. 2. The tempering frame 21 can be moved by a tempering frame movement mechanism (not shown in detail) between the bending chamber 2 and the tempering zone 4 (e.g., in a horizontal plane). Preferably, the tempering frame 21 can be moved back and forth translationally in a horizontal plane between a first tempering frame position 22 situated between the two tempering boxes 20 and a second tempering frame position 23 within the bending chamber 2 situated, for example, directly below the stationary mold 11.

[0082] In order to couple the tempering zone 4 to the bending chamber 2, the bending chamber wall 9 has a first bending chamber opening 24, which opens into the bending chamber cavity 10. The first bending chamber opening 24 can be closed by a first bending chamber door 25 such that the bending chamber cavity 10 can be open to the outside or closed against the external environment. The tempering frame 21 can be moved through the opened first bending chamber opening 24 into the bending chamber cavity 10 in order to receive a finished bent sheet 52 and to transport it into the tempering zone 4. From there, the tempered sheet 52 can be removed easily and further processed.

[0083] The device 1 further includes a movable (mobile) press frame module 6, which is arranged opposite the tempering zone 4 on the outside of the bending chamber 2. Like the bending chamber 2, the press frame module 6 is designed here, for example, in the form of a closed or closable chamber. The press frame module 6 includes an insulating press frame module wall 26, which delimits a cavity of the press frame module 6, referred to in the following as “press frame module cavity 27”, from the external environment. The press frame module cavity 27 is accessible from the outside through at least one press frame module opening 28 that opens into the press frame module cavity 27. The press frame module opening 28 can be closed by a press frame module door 29.

[0084] As depicted in FIG. 2, the press frame module 6 is arranged outside the bending chamber 2, with the press frame module opening 28 in a position opposite a second bending chamber opening 30 of the bending chamber cavity 10. The bending chamber cavity 10 is accessible from the outside through the second bending chamber opening 30 that opens into the bending chamber cavity 10. The second bending chamber opening 30 can be closed by a second bending chamber door 31. When the press frame module 6 is arranged on the bending chamber 2, the bending chamber cavity 10 and the press frame module cavity 27 can be spatially connected to one another by opening both the press frame module door 29 and the second bending chamber door 31. On the other hand, the press frame module cavity 27 can be spatially separated from the bending chamber cavity 10 by closing the press frame module door 29 and/or the second bending chamber door 31.

[0085] The press frame module 6 is movable relative to the bending chamber 2 and has, for this purpose, an actively or passively drivable press frame module movement mechanism 32 for moving the press frame module 6 (for example, roller bearings). By means of the press frame module movement mechanism 32, the press frame module 6 can be delivered to the bending chamber 2 or removed from the bending chamber 2.

[0086] The press frame module cavity 27 is surrounded by an insulating press frame module wall 26. As a result, the press frame module cavity 27 can be heated to and maintained at a desired temperature. For example, the press frame module cavity 27, like the bending chamber 2, is heated to a temperature (bending temperature) suitable for the bending operation of the sheets 52. For heating the press frame module cavity 27, the press frame module 6 has a press frame module heating device 34, which is implemented in the form of radiant heaters in the embodiment of FIG. 2. The radiant heaters are, for example, distributed in a plurality of radiant heater arrays.

[0087] The press frame module 6 also has an elongated press frame carrier 35 for the press frame 8. The press frame carrier 35 is movable by a press frame carrier movement mechanism 36. The press frame carrier movement mechanism 36 is arranged outside the heatable press frame module cavity 27 (below the press frame module cavity 27 in FIG. 2). In the exemplary embodiment depicted, the press frame carrier movement mechanism 36 includes a pinion chain mechanism equipped with a driven pinion, which is known to the person skilled in the art and does not need to be explained in detail. In the situation depicted in FIG. 2, the press frame carrier 35 is situated completely within the press frame module cavity 27. The press frame module door 29 and the second bending chamber door 31 are in a closed position in each case. The press frame 8, which is used to press and store a sheet 63 [sic], is fixedly attached to the free end of the press frame carrier 35. For this purpose, the press frame carrier 35 comprises, for example, two parallel carrier arms, between which the press frame 8 is fastened.

[0088] In the device 1 according to the invention, a movement of the press frame 8 within the bending chamber 2 is done by the press frame carrier 35 supplied from outside the bending chamber 2, wherein due to the fact that the press frame carrier movement mechanism 36 is arranged outside the heatable press frame module cavity 27, very precise positioning of the press frame 8 is made possible in a particularly advantageous manner.

[0089] Reference is now made to FIG. 3, wherein the device 1 is depicted according to the sectional view A-A of FIG. 2 in a different situation of the method. In order to avoid unnecessary repetition, only the differences relative to FIG. 2 are explained; and, otherwise, reference is made to the above statements. In the situation of FIG. 3, the tempering frame 21 is situated in the first tempering frame position 22 between the two tempering boxes 20. The press frame 8 was transported within the bending chamber 2 by moving the press frame carrier 35 from a press frame resting position 37 into a press frame working position 38. The free end of the press frame carrier 35 carrying the press frame 8 was introduced, for this purpose, into the bending chamber cavity 10 (a part of the press frame carrier 35 is still situated in the press frame module 6). As a result of heating the press frame module cavity 27 by means of the the press frame module heating device 34, the press frame 8 can also be heated quickly outside the bending chamber cavity 10 to a temperature suitable for bending sheets 52. Particularly advantageously, the bending chamber cavity 10 can be closed by closing the bending chamber doors 25, 31, for example, in order to remove the press frame module 5 from the bending chamber 2, without the bending chamber cavity 10 being exposed to the external environment, whereby, in particular, a greater temperature drop in the bending chamber cavity 10 can be avoided. Accordingly, another module can be coupled with the bending chamber 2 in a simple manner.

[0090] Reference is now made to FIG. 4, wherein a part of the device 1 of FIG. 1 according to the sectional plane B-B (perpendicular to the sectional plane A-A) is depicted. FIG. 4 depicts the bending chamber 2, the mold carrier module 5 arranged on the bending chamber 2 and functionally coupled therewith, as well as a part of the preheating zone 3. As already described in connection with FIG. 2, the bending chamber 2 includes the bending chamber cavity 10, in which the stationary mold 11 is arranged. The stationary mold 11 has a contact surface 15 with an outer surface section 16 and an inner surface section 17.

[0091] Arranged on the bending chamber 2 and functionally coupled therewith is the preheating zone 3, in which sheets 52 can be heated to a temperature suitable for bending. In the device 1, sheets can be successively transported from the preheating zone 3 into the bending chamber 2 and, finally, into the tempering zone 4. For transport of the sheets from the preheating zone 3 into the bending chamber 2, for example, a roller bed with a plurality of cylindrical rollers is provided for the areal support of sheets 52.

[0092] Still referring to FIG. 4, the movable (mobile) mold carrier module 5, which is arranged opposite the preheating zone 3 on the outside of the bending chamber 2, is described. The mold carrier module 5 includes a substructure 43, on which a mold carrier 44 is attached. A mold 7 is fixedly attached at the end of the mold carrier 44, which mold 7 becomes a transportable mold due to the movability of the mold carrier 44. The mold carrier 44 opens into a mold carrier module cavity 46 surrounded by a mold carrier module wall 45 and open to the bending chamber 2, in which the transportable mold 7 is arranged. The bending chamber wall 9 has, on the side to which the mold carrier module 5 can be delivered, a fourth bending chamber opening 47. When the mold carrier module 5 is delivered to the bending chamber 2, the mold carrier module cavity 46 opens into the bending chamber cavity 10. The mold carrier module wall 45 makes physical contact with the outside of the bending chamber wall 9. Not shown in FIG. 4, but possible, would be providing the fourth bending chamber opening 47 and/or the mold carrier module cavity 46 in each case with a door for separate closing.

[0093] The mold carrier module cavity 46 can be heated to a desired temperature. For example, the mold carrier module cavity 46, like the bending chamber 2, is heated to and maintained at a temperature (bending temperature) suitable for a bending operation of the sheets 52, in order to heat the transportable mold 7 to such a temperature. The mold carrier module cavity 46 has, for this purpose, a heating device (e.g., radiant heater) designed in the form of radiant heaters (not shown in FIG. 4). The hot and cold regions are identified in FIG. 4 by “H(ot)” and “C(old)”.

[0094] The mold carrier module 5 is movable relative to the bending chamber 2 and has, for this purpose, an actively driven or passively drivable mold carrier module movement mechanism 50 for moving the mold carrier module 5. In the present exemplary embodiment, the mold carrier module movement mechanism 50 includes a plurality of passively drivable wheels 49. By means of the mold carrier module movement mechanism 50, the mold carrier module 5 can be delivered to the bending chamber 2 or removed from the bending chamber 2.

[0095] The mold carrier module 5 has the elongated mold carrier 44 for the transportable mold 7. The mold carrier 44 is movable vertically by a mold carrier movement mechanism 48 and with a horizontal movement component such that the mold 7 attached on the mold carrier 44 can be introduced into the bending chamber 2 for the processing of a respective sheet 52 and removed again therefrom. The mold carrier movement mechanism 50 is arranged outside the heatable mold carrier module cavity 46 such that, in a particularly advantageous manner, very precise positioning of the transportable mold 7 within the bending chamber 2 is made possible.

[0096] The transportable mold 7 can be moved by moving the mold carrier 44 within the bending chamber 2 with a horizontal movement component and vertically (one dimensionally and reciprocally in each case). The transportable mold 7 has a downward directed contact surface 15′, which is composed of an outer surface section 16′ and an inner surface section 17′.

[0097] The contact surfaces 15, 15′ of the molds 11, 7 can have the same or different surface contours. Preferably, the surface contours are different from one another. For example, the outer surface section 16′ of the contact surface 15′ of the transportable mold 7 has a surface contour that is adapted to a desired edge final bending, i.e., final bending, in a (for example, strip-shaped) edge region 53 of the sheet 52 or enables such final bending in the further processing of the sheet 52. The end edge region of the sheet 52 is adjacent a sheet (cut) edge arranged perpendicular to the two opposing primary surfaces of the sheet. The inner surface section 17′ of the contact surface 15′ of the transportable mold 7 has a surface contour that corresponds to a surface pre-bending, i.e., non-final bending in an inner region 54 of the sheet 52 completely surrounded by the edge region. The outer surface section 16 of the contact surface 15 of the stationary mold 11 has the same surface contour as the outer surface section 16′ of the contact surface 15′ of the transportable mold 7 and has a surface contour that is adapted to the desired edge final bending in the edge region 53 of the sheet 52. In contrast to the inner surface section 17′ of the contact surface 15′ of the transportable mold 7, the inner surface section 17 of the contact surface 15 of the stationary mold 11 has a surface contour that is adapted to a surface final bending, i.e., a final or quasi-final bending, in the inner region 54 of the sheet 52 or makes this possible in the further processing.

[0098] The transportable mold 7 further has a combined suction/blowing device 18′ (not shown in detail) for sheets, by means of which a sheet 52 can be sucked against the contact surface 15′ and thus temporarily fixed on the contact surface 15′ or removed from the contact surface 15′. A negative or positive pressure on the contact surface 15′ can be generated based on the Venturi principle by a Venturi device 13 that is situated in the cold region of the mold carrier module 5.

[0099] In the device 1, the press frame 8 is used for storage and pressing of sheets in cooperation with a mold. For this purpose, the press frame 8 has an edge (e.g., strip-shaped) press surface 51 (see FIGS. 21A and 21B), whose surface contour is, for example, complementary to the surface contour of the outer surface sections 16, 16′ of the stationary mold 11 and the transportable mold 7. The upward facing press surface 51 is suitable for pressing a sheet 52 resting thereon in an edge region 53. The press frame 8 is not designed as a full surface, but, instead, has an internal opening that allows surface pre-bending of the inner region 54 of a sheet 52 placed thereon by gravity.

[0100] Supplementing FIG. 4, reference is now made to FIGS. 5 to 20, which depict sectional views of the device 1 analogous to FIG. 4, in order to describe an exemplary embodiment of the method according to the invention. In order to avoid unnecessary repetition, in each case only the differences of the method situations depicted are described; otherwise, reference is made to the statements above.

[0101] FIG. 4 depicts a starting situation in which the transportable mold 7 is situated within the mold carrier module cavity 46 and has been heated to a temperature suitable for the processing of sheets. For this purpose, the bending chamber cavity 10 and the mold carrier module cavity 46 are heated to one and the same temperature. The transportable mold 7 can, in particular, be arranged completely within the mold carrier module cavity 46. The stationary mold 11 is situated within the bending chamber 2. A sheet 52, which is heated to a temperature suitable for bending, is situated in the preheating zone 3 (not shown).

[0102] FIG. 5 depicts the device 1 for bending sheets at a later time than in FIG. 4. The sheet 52 is situated in a removal position. The mold carrier 44 is moved horizontally into the bending chamber 2, with the transportable mold 7 situated in a position vertically elevated directly above the sheet 52. The stationary mold 11 is also situated in the bending chamber 2 and is arranged above and/or to the side of the transportable mold 7. Preferably, the stationary mold 11 is moved far enough upward in the bending chamber 2 that there is space for the transportable mold 7 vertically directly below the stationary mold 11.

[0103] FIG. 6 depicts the device 1 for bending sheets at a later time than in FIG. 5. The mold carrier 44 with the transportable mold 7 situated thereon has been lowered vertically such that the transportable mold 7 is now situated just above the sheet 52. There has been no change in the position of the transportable mold 7 horizontally.

[0104] FIG. 7 depicts the device 1 for bending sheets at a later time than in FIG. 6. The sheet 52 is raised from the removal position in the direction of the transportable mold 7 by blowing with the fluid flow of a gaseous fluid, here, for example, an air flow 55 (symbolically represented by arrows) vertically generated by the blowing device 19 on its underside and finally pressed by the air flow 55 against its contact surface 15′. The transportable mold 7 has been lowered, for this purpose, far enough that the sheet 52 can be pressed against the contact surface 15′ by the air flow 55.

[0105] FIG. 8 depicts the device 1 for bending sheets at a later time than in FIG. 7. The sheet 52 is pressed against the contact surface 15′ by the air flow 55. In addition, the sheet 52 is fixed on the contact surface 15′ by suction by means of the suction/blowing device 18′. The suction/blowing device 18′ temporarily fixes the sheet 52 against the contact surface 15′ by means of a vacuum. This is depicted symbolically in FIG. 8 by arrows pointing upward.

[0106] As a result of the typically incomplete contact against the contact surface 15′, a pre-bending of the sheet 52 occurs only in the edge region 53. Generally, the pressing pressure from the air flow 55 is not sufficient to produce edge final bending in the edge region 53 of the sheet 52. On the other hand, the sucking action of the suction/blowing device 18′ serves substantially only for holding the sheet 52 against the contact surface 15′ until the press frame 8 has traveled under the sheet 52 should and has only a slight influence on the bending of the sheet 52. Nevertheless, bubbles in the sheet 52 can be removed thereby. In the inner region 54 of the sheet 52, only pre-bending of the surface is still possible as result of the contact surface 15′. FIG. 8 depicts a situation in which the sheet 52 is already fixed against the contact surface 15′.

[0107] FIG. 9 depicts the device 1 for bending sheets at a later time than in FIG. 8. The air flow 55 coming from below has been stopped. The sheet 52 is fixed against the contact surface 15′ only by the negative pressure generated by the suction/blowing device 18′. The mold carrier 44 with the transportable mold 7 and the sheet 52 fixed thereon has been moved upward vertically.

[0108] FIG. 10 depicts the device 1 for bending sheets at a later time than in FIG. 9. Depicted here is a situation in which the press frame 8 has been moved vertically into the press frame working position 38 directly below the sheet 52 (direction of movement in FIG. 10: into the plane of the drawing). The mold carrier 44 with the transport mold 7 and the sheet 52 fixed thereon is still situated in an elevated position.

[0109] FIG. 11 depicts the device 1 for bending sheets at a later time than in FIG. 10. The transportable mold 7 has been brought, by lowering the mold carrier 44 vertically downward from the elevated position, to a lowered position, in which the sheet 52 fixed against the contact surface 15′ has areal contact with the press frame 8.

[0110] FIG. 12 depicts the device 1 for bending sheets at a later time than in FIG. 11. The sheet 52 is now placed on the press frame 8. To assist this, the sheet 52 is blown on by a stream of a gaseous fluid generated by means of the suction/blowing device 18′. Thus, undesired adhesion of the sheet 52 on the contact surface 15′ can be avoided. The press surface 51 preferably has a shape complementary to the outer surface section 16′ of the contact surface 15′. Optionally, the sheet 52 can be pressed between the contact surface 15′ of the transportable mold 7 and the press frame 8, illustrated here by downward pointing arrows. The sheet 52 is pressed in the edge region 53 between the outer surface section 16′ of the contact surface 15′ and the press surface 51 of the press frame 8 (see FIGS. 21A and 21B). On the press frame 8, the edge region 53 of the sheet 52 is pre-bent or finish bent passively by its own weight as well as, optionally, actively by pressing. A major advantage of pressing the sheet 52 against the press frame 8 is a resultant very precise definition of the position of the sheet 52 on the press frame 8 with exact contact of the edge region 53 of the sheet 52 on the press surface 51 of the press frame 8. This enables precise positional fixing of the sheet 52 on the press frame 8 by stoppers abutting the sheet 52 (not shown in detail). Thus, particularly high production accuracy and good optical quality of the bent sheet can be achieved. The fixing of the sheet 52 on the contact surface 15′ was released by stopping the suction action of the suction/blowing device 18′.

[0111] FIG. 13 depicts the device 1 for bending sheets at a later time than in FIG. 12. The mold carrier 44 and, with it, the transportable mold 7 has been moved vertically upward. During storage on the press frame 8, the sheet 52 is additionally passively pre-bent by its own weight in the inner region 54. If pressing occurs in the edge region 53, the surface pre-bending by gravity im inner region 54 can be restricted.

[0112] FIG. 14 depicts the device 1 for bending sheets at a later time than in FIG. 13. The sheet 52 is still stored on the press frame 8. The mold carrier 44 has been moved back horizontally from the bending chamber 2 into the mold carrier module 5, with the transportable mold 7 situated within the mold carrier module cavity 46.

[0113] FIG. 15 depicts the device 1 for bending sheets at a later time than in FIG. 14. The stationary mold 11 has been lowered vertically onto the sheet 52, which rests on the press frame 8, and pressed in the edge region 53 between the outer surface section 16 of the contact surface 15 and the press surface 51 of the press frame 8. The press surface 51 has a shape complementary to the outer surface section 16 of the contact surface 15. The edge region 53 of the sheet 52 is thereby preferably finish bent, i.e., obtains its edge final bending. However, it is also possible for the edge region 55 of the sheet 52 to be (further) pre-bent. During storage of the sheet 52 on the press frame 8, the press frame 8 is not moved such that there is no risk of sheet 52 changing position on the press frame 8 and sheets 52 with particularly high quality can be produced.

[0114] FIG. 16 depicts the device 1 for bending sheets at a later time than in FIG. 15. After pressing, the sheet 52 is fixed on the contact surface 15 of the stationary mold 11 by suction by means of the suction/blowing device 18. The fluid flow generating negative pressure on the contact surface 15 is represented symbolically by arrows. FIG. 16 depicts a situation in which the stationary mold 11 with a sheet 52 fixed thereon has been moved upward vertically. In contrast to the transportable mold 7, where, for example, the intention is only to hold the sheet 52 and the negative pressure, consequently, does not cause bending (at least not appreciably) of the sheet 52, the suction of the sheet 52 against the contact surface 15 can also be used to bend the sheet 52, i.e., the suction generates sufficient mechanical pressure to bend the sheet 52 in the manner desired. The sheet 52 can thus be pre-bent against the contact surface 15 in the inner region. In addition, previously produced edge final bending in the edge region 53 can be maintained on the sheet 52.

[0115] FIG. 17 depicts the device 1 for bending sheets at a later time than in FIG. 16. FIG. 17 depicts a situation in which the press frame 8 has been moved by moving the press frame carrier 35 in a horizontal plane from the press frame working position 38 within the bending chamber 2 into the press frame resting position 37 within the press frame module cavity 27 of the press frame module 5. The tempering frame 21 has been moved from the first tempering frame position 22 between the two tempering boxes 20 into the second tempering frame position 23 within the bending chamber 2. The second tempering frame position 23 is situated directly below the stationary mold 11 vertically. To enable entry into the bending chamber 2, the first bending chamber door 25 was opened for a short time, as a result of which an appreciable temperature loss can be avoided.

[0116] FIG. 18 depicts the device 1 for bending sheets at a later time than in FIG. 17. Here, the stationary mold 11 with a sheet 52 fixed thereon has been moved downward vertically, whereby the sheet 52 is placed on the tempering frame 21. The fixing of the sheet 52 on the contact surface 15 was released by stopping the suction action of the suction/blowing device 18. The placing of the sheet 52 is assisted by blowing with a fluid flow generated by means of the suction/blowing device 18.

[0117] FIG. 19 depicts the device 1 for bending sheets at a later time than in FIG. 18. FIG. 19 depicts a situation in which the stationary mold 11 has been moved upward vertically. The sheet 52 is placed on the tempering frame 21.

[0118] FIG. 20 depicts the device 1 for bending sheets at a later time than in FIG. 19. Here, the sheet 52 on the tempering frame 21 has been moved from the second tempering frame position 23 within the bending chamber 2 into the first tempering frame position 22 between the two tempering boxes 20, where the sheet 52 is tempered. In order to allow the tempering frame 21 with the sheet 52 placed thereon to leave the bending chamber 2, the first bending chamber door 25 was opened for a short time, as a result of which an appreciable temperature loss can be avoided. Edge final bending and surface final bending of the sheet 52 by gravity can be done during transport on the tempering frame 21. For this purpose, the tempering frame 21 preferably has an upward directed frame surface for contact with the sheet 52, which is suitably designed for edge final bending. In addition, the tempering frame 21 is preferably suitably designed for surface final bending by gravity.

[0119] As shown in FIG. 20, another sheet 52, which has been heated to a temperature suitable for bending, can now be transported into the bending chamber 2. The situation of FIG. 20 is similar to the situation of FIG. 4. In this manner, the bending process can be carried out continuously.

[0120] FIG. 22 illustrates the successive steps of an exemplary method for producing the sheet 52 by means of the device 1 with reference to a flow chart.

[0121] Here, in a first step I, a sheet 52 heated to bending temperature is provided in the removal position within the bending chamber 2. In a second step II, the sheet 52 is fixed on the contact surface 15′, 15 of a mold, selected from the transportable mold 7 and the stationary mold 11. In a third step III, the press frame 8 is positioned in the press frame working position 38 within the bending chamber 2. In an optional fourth step IV, pressing can be done between the contact surface 15′, 15 of the mold 7, 11, on which the sheet 52 is fixed, and the press frame 8. In a fifth step V, the sheet 52 is placed on the press frame 8. In a sixth step VI, the sheet 52 is pressed between the contact surface 15, 15′ of the respective other (not selected in step II) mold 7, 11 and the press frame 8. In a seventh step VII, the sheet 52 is fixed on the contact surface 15, 15′ of the mold 11, 7, with which the pressing was last done. In an eighth step VIII, the tempering frame 21 is positioned in the second tempering frame position 23 in the bending chamber 2. In a ninth step IX, the sheet 52 is placed on the tempering frame 21. In a tenth step X, the sheet 52 is transported on the tempering frame 21 to the tempering zone 4 for thermal tempering of the sheet 52.

[0122] According to a first alternative, in which the transportable mold 7 is used for the first fixing of the sheet 52 and the stationary mold 11 is used for the second fixing of the sheet 52, the transportable mold 7 is introduced into the bending chamber before the fixing of the sheet 52 on its contact surface 15′ and is removed again from the bending chamber 2 after the placing of the sheet 52 on the press frame 8. In contrast to this, the stationary mold 11 remains permanently in the bending chamber 2 at least from the provision of the sheet 52 in the bending chamber 2 until the transporting of the sheet 52 on the tempering frame 21.

[0123] According to a second alternative, in which the stationary mold 11 is used for the first fixing of the sheet 52 and the transportable mold 7 is used for the second fixing of the sheet 52, the transportable mold 7 is introduced into the bending chamber 2 after placing the sheet 52 on the press frame 8 and is removed from the bending chamber 2 after placing the sheet 52 on the tempering frame 21. In this case, the stationary mold 11 remains permanently in the bending chamber 2 at least from the provision of the sheet 52 in the bending chamber 2 until the transporting of the sheet 52 on the tempering frame 21.

[0124] From the above statements, it emerges that the invention enables fast and economical production even of complexly curved sheets. Existing systems for bending sheets can easily be retrofitted with the transportable mold introduced into the bending chamber from outside. The insertion and removal of the transportable mold make room for the use of the stationary mold, i.e., processing of sheets by multiple molds is made possible in a simple manner. In particular, the quality of the sheets can be further improved if a change in position of the molds occurs only vertically and the sheets are not moved during storage on the press frame. In this connection, the accuracy of the positioning of the sheet on the press frame by the pressing of the sheet between the mold and the press frame in the edge region of the sheet is particularly advantageous. The transportable mold that can be introduced into the bending chamber from the outside can be positioned within the bending chamber with particularly high accuracy. This is true in particular when a movement mechanism for the mold carrier is arranged outside a heated region. In addition, the molds can be exchanged and/or serviced quickly and easily. Particularly advantageously, the transportable mold can be heated before use such that the processing of sheets can be carried out quickly, in particular after a mold change. The invention thus enables particularly economical production of, in particular, complexly shaped sheets with relatively short cycle times and particularly high quality requirements.

LIST OF REFERENCE CHARACTERS

[0125] 1 device [0126] 2 bending chamber [0127] 3 preheating zone [0128] 4 tempering zone [0129] 5 mold carrier module [0130] 6 press frame module [0131] 7 transportable mold [0132] 8 press frame [0133] 9 bending chamber wall [0134] 10 bending chamber cavity [0135] 11 stationary mold [0136] 12 holder [0137] 13 Venturi device [0138] 14 holder movement mechanism [0139] 15, 15′ contact surface [0140] 16, 16′ outer surface section [0141] 17, 17′ inner surface section [0142] 18, 18′ suction/blowing device [0143] 19 blowing device [0144] 20 tempering box [0145] 21 tempering frame [0146] 22 first tempering frame position [0147] 23 second tempering frame position [0148] 24 first bending chamber opening [0149] 25 first bending chamber door [0150] 26 press frame module wall [0151] 27 press frame module cavity [0152] 28 press frame module opening [0153] 29 press frame module door [0154] 30 second bending chamber opening [0155] 31 second bending chamber door [0156] 32 press frame module movement mechanism [0157] 33 preheating zone heating device [0158] 34 press frame module heating device [0159] 35 press frame carrier [0160] 36 press frame carrier movement mechanism [0161] 37 press frame resting position [0162] 38 press frame working position [0163] 39 roller bed [0164] 40 roller [0165] 41 removal position [0166] 42 third bending chamber opening [0167] 43 substructure [0168] 44 mold carrier [0169] 45 mold carrier module wall [0170] 46 mold carrier module cavity [0171] 47 fourth bending chamber opening [0172] 48 mold carrier module movement mechanism [0173] 49 wheel [0174] 50 mold carrier movement mechanism [0175] 51 press surface [0176] 52 sheet [0177] 53 edge region [0178] 54 inner region [0179] 55 air flow