Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B23/00—Re-forming shaped glass
  • C03B23/02—Re-forming glass sheets
  • C03B23/023—Re-forming glass sheets by bending
  • C03B23/03—Re-forming glass sheets by bending by press-bending between shaping moulds
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B23/00—Re-forming shaped glass
  • C03B23/02—Re-forming glass sheets
  • C03B23/023—Re-forming glass sheets by bending
  • C03B23/025—Re-forming glass sheets by bending by gravity
  • C03B23/0252—Re-forming glass sheets by bending by gravity by gravity only, e.g. sagging
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B27/00—Tempering or quenching glass products

Definitions

• the invention relates to a device and a method for bending glass sheets, in particular for press bending glass sheets.
• Automotive glazings typically have a bend.
• Various methods for producing such a bend are known.
• gravity bending also gravity bending or sag bending
• the glass pane in the initial state is arranged on the bearing surface of a bending mold and heated to at least its softening temperature, so that it bears against the bearing surface under the influence of gravity.
• press bending processes the disk is placed between two complementary tools that together exert a pressing action on the disk to produce the bend.
• US 5882370 A discloses a lower bending mold, which is used both for generating a pre-bend by means of gravity bending and as a lower press bending mold and has the articulated edge regions.
• the edge regions are initially positioned below, so that the bending mold is formed relatively flat when the flat disc is deposited thereon, and are pivoted upward with increasing disc bending in order to gently realize a greater bending in the edge region.
• the tools are very complex with hinges and means for generating the pivoting motion, which increases manufacturing, maintenance intensity and susceptibility to failure.
• US2005268661A1 discloses a lower press bending mold having a concavely curved contact surface.
• the present invention has for its object to provide an improved press bending device, can be realized with the strong disc curvatures in the edge region, without more complex bending processes are necessary.
• a device for bending glass sheets comprising:
• an upper press bending mold is arranged opposite the contact surface
• the lower press bending mold and the upper press bending mold being adapted to press-deform a glass sheet (heated to the softening temperature) between them, the side edge of the glass sheet resting on a contact line on the contact surface,
• the object of the invention is also achieved by a method for bending glass sheets, comprising the following method steps:
• the contact surface between the first contact line and the pressing line is convexly curved.
• the convex curvature of the contact surface is opposite to the direction of curvature of the glass sheet.
• the contact surface is therefore bent as it were away from the glass, thereby preventing the disk main surface comes into contact with the contact surface. Instead, the line-like contact along the side edge of the glass remains ensured even with strong disc curvatures.
• the lower press bending mold according to the invention makes it possible to produce glass sheets with a high degree of curvature, in particular in the edge region and high optical quality. However, no elaborate adjustments of the bending devices and methods are required. All that is needed is to replace the lower press bending mold of existing devices with the invention. Thus, the invention can be easily integrated into existing plants and processes. These are great advantages of the present invention.
• the device according to the invention comprises a lower and an upper press bending mold.
• the press bending molds are arranged opposite each other and have complementary active or contact surfaces which are suitable for bending a softening-temperature-heated glass sheet into the desired shape by pressing it between the press bending molds, whereby the disk curvature is changed.
• a lower bending mold is understood to mean a shape which touches or is associated with the lower, ground-facing surface of the glass pane and acts on it.
• An upper bending mold is understood to mean a shape that touches or is associated with the upper surface of the glass pane facing away from the ground and acts on it.
• the bending forms can also be referred to as bending tools.
• the lower Pressbiegeform has a contact surface which is formed like a frame. With contact surface while a substantially upwardly facing, facing away from the ground surface is designated, which is intended to carry the glass sheet during pressing.
• the contact surface is bounded by edges, and Although by an outer edge and an inner edge, each running circumferentially like a frame.
• the inner edge is facing the center and in the intended use of the glass sheet center.
• the outer edge faces outward and, in the intended use, faces away from the center of the glass pane. During the bending process, not the entire contact surface comes into direct contact with the glass pane, but only the area between the first contact line and the pressing line.
• the contact surface is not a so-called full form, so no massive bending mold, which is intended to come into contact with a large part of the glass sheet. Instead, the contact surface in the form of a frame or -shaped and adapted to the contour of the glass sheet to be bent, so that it is adapted to contact the peripheral side edge of the glass sheet. Such a bending form may also be referred to as a ring (bending ring) or frame (frame shape).
• the lower surface of the glass sheet has no direct contact with the contact surface, but only its side edge.
• the contact surface does not necessarily have to form a complete frame, but may also be interrupted.
• the contact surface is in the form of a complete or interrupted frame.
• the glass sheet is first brought into contact with the lower or the upper press bending mold before the press bending.
• the glass sheet can be placed on the lower Pressbiegeform and then approximated to the upper Pressbiegeform.
• the glass sheet may first be received by the upper press-bending mold, for example by suction or blowing action, and then approximated to the lower press-bending mold.
• only the side edge of the glass pane comes into contact with the contact surface of the lower press bending mold.
• the direct contact between glass and contact surface is thus formed linear or linear, said line is referred to in the context of the invention as a contact line.
• the contact line is circumferentially formed like a frame on the contact surface.
• the contact line along which the glass pane first contacts the contact surface when the tools approach each other before the onset of deformation is referred to as the first contact line in the sense of the invention.
• the first contact line In the sense of the invention.
• the contact line migrates during the bending process as from the Cleartitleline inward to the pressing line.
• the direct contact between the glass pane and the lower bending mold is always only linear along the contact line during the entire bending process.
• the lower disc surface never comes into contact with the lower bending mold.
• the peripheral side edge extends between the upper and lower disc surfaces. Specifically, in particular, the boundary line between the lower disk surface and the side edge is in contact with the contact surface.
• the contact surface of the lower press bending mold has at least one section in which it is convexly curved at least in the region between the first contact line and the pressing line.
• the glass sheet is pressed by the upper press bending mold into the lower press bending mold in such a way that the center of the pane falls and the edge of the pane is raised relative to the center of the pane.
• the glass sheet is thus bent so that the lower disk surface is convex and the upper disk surface is concavely curved.
• the contact surface is convexly curved so that the curvature of the contact surface and the curvature of the glass are opposite to each other.
• the height of the contact surface decreases in the direction from the outer edge to the inner edge.
• the inner region of the contact surface is thus bent away from the glass pane, so that even with strong disk bends it is avoided that the contact surface touches the lower disk surface.
• the curvature of the invention need not necessarily be circumferentially present on the entire contact surface. It is also possible that only portions of the contact surface are provided with the curvature according to the invention, while other portions are formed in a conventional manner. This can occur, for example, if the glass pane is strongly curved in the region of part of its side edge, while it does not have too great a curvature in the region of the remaining side edge. Then it may be advantageous to equip only the areas of the contact surface, which are assigned to the strongly curved side edges, with the curvature according to the invention.
• the extent of the required curvature of the contact surface depends essentially on the geometry of the glass sheet to be bent and can be determined by means of customary calculations in the planning of the bending tool.
• the curvature is chosen in particular such that the lower disk surface does not touch the contact surface even in the final bent state. From the lower disk surface and the contact surface so always an angle greater than 0 ° should be included, which is referred to in the context of the invention as a clearance angle. Due to the disc curvature, the respective tangential plane at the contacting line must be used for the exact determination of the clearance angle.
• the clearance angle between the glass pane and the contact surface on the pressing line is preferably at least 3 °, particularly preferably at least 5 °, for example from 5 ° to 8 °.
• the disk surface and contact surface are sufficiently spaced to effectively exclude a direct contact, taking into account manufacturing tolerances.
• the radius of curvature of the contact surface between Cleartitleline and pressing line should advantageously be at most 750 mm, preferably at most 500 mm. In order to achieve particularly good results with conventional radii of curvature of the glass sheet to be bent and ensures a sufficient clearance angle.
• the radius of curvature of the direction from the first contact line to the pressing line increases at least in sections, ie the curvature becomes weaker from the outside to the inside.
• the cross section of the first contact line to the pressing line so there exists at least a portion of the contact surface in which the curvature is stronger from outside to inside.
• the inner edge of the contact surface is lowered further and the risk of contact between the disk surface and contact surface is further reduced. It is particularly advantageous if the radius of curvature increases in the entire area between the first contact line and the pressing line from outside to inside.
• the distance between the first contact line and the pressing line is from 2 cm to 50 cm, preferably from 5 cm to 30 cm. Said distance is measured along the shortest connection on the contact surface between first contact line and pressing line, in particular substantially perpendicular to the two lines. With the specified distances particularly good bending results can be achieved.
• the distance between the pressing line and the inner edge of the contact surface is preferably at least 10 mm, for example from 10 mm to 100 mm.
• the distance between the first contact line and the outer edge of the contact surface is preferably at least 5 mm, for example from 5 mm to 100 mm.
• the upper Pressbiegeform is formed in an advantageous embodiment as a so-called full form, so has a full-surface downwardly facing contact or active surface.
• an effective surface which can also be termed solid, contacts a large part of the upper disk surface - or even the entire upper disk surface - at the end of the bending step.
• a massive upper press bending mold in combination with a frame-like lower press bending mold, is particularly suitable for press bending.
• the active surface of the upper press bending mold is in particular convexly shaped and has a geometry which corresponds to that of the final bent disk.
• the contact surfaces of the two press bending forms are typically not covered with a fabric, in particular metal-containing fabric, during press bending, as is usual in other bending forms. Instead, the glass sheet is in direct contact with the metallic surfaces of the bending molds.
• the device according to the invention also detects means for moving the lower and upper press bending molds against each other. As a result, after the glass sheet has been positioned for bending, both press bending molds are brought closer to each other, so that they can press together on the glass pane.
• the approach can be made by vertical movement of the lower press bending mold, the upper press bending mold or both.
• the device according to the invention also detects means for heating the glass sheet to softening temperature.
• the bending molds are disposed within a heatable bending furnace or a heatable bending chamber.
• the glass sheet may pass through a separate chamber for heating, such as a tunnel oven.
• the apparatus also includes means for moving the glass sheet to be bent to transport the glass sheet back to the heating means and away from the heating medium after bending.
• the press bending molds can be movably mounted, for example, on a caddy that is moved by means of rollers or treadmills.
• the bending molds may be stationary in the bending oven and the glass sheet may be moved directly onto rollers or treadmills.
• the glass pane can be picked up, for example, from the upper press bending mold.
• the glass sheet can be sucked from the upper press bending mold or be blown by a vertical air flow to the upper Pressbiegeform.
• the glass sheet is pre-bent prior to press bending, and the apparatus is provided with appropriate means for generating the pre-bend.
• the pre-bending can be done for example by blowing the softened glass sheet to the upper Pressbiegeform.
• the pre-bend may be generated by gravity bending.
• the device is equipped with a gravity bending mold, which preferably has a frame-shaped, limited by an inner edge and an outer edge support surface. Only one edge region of the glass pane is in direct contact with the support surface, while the largest part of the glass pane has no direct contact with the gravity bending mold.
• the encircling side edge of the glass pane can be arranged on the support surface or also protrude in sections or circumferentially over the support surface.
• the disk center decreases under the force of gravity and the disk edges are raised relative to the disk center, producing the pre-bend.
• the combination of gravity bending to create a pre-bend and press bending to final bend glass panels with complex geometries can be produced in high optical quality.
• the device then preferably comprises means for arranging the glass sheet on the gravity bending mold, in particular an upper transport mold with downward contact surface.
• the glass pane is sucked or blown onto the contact surface.
• the gravity bending mold is moved under the transport form (or alternatively the transport form on the gravity bending mold), optionally approximated to the transport form and by switching off the suction or blowing action, the glass is placed on the support surface of the gravity bending mold.
• the contact surface of the transport form is preferably flat, whereby the flat glass pane in the initial state can be optimally transported.
• the device may, for example, specifically comprise means for moving the glass sheet from the gravity bending mold to the lower press bending mold, for example another one upper transport form. It can also be lifted from the gravity bending mold by blowing it against the upper press bending mold, after which the gravity bending mold is swapped against the lower press bending mold to prepare the press bending apparatus.
• the gravity bending mold and the lower press bending mold are combined in a common tool, wherein the contact surface of the lower press bending mold frames the bearing surface of the gravity bending mold or vice versa.
• the contact surface of the lower press bending mold and the support surface of the gravity bending mold are movable relative to each other by vertical displacement, such that between a first state in which the support surface of the gravity bending mold is arranged higher than the contact surface of the lower Pressbiegeform, and a second state in which the contact surface of the lower press bending mold is arranged higher than the support surface of the gravity bending mold, can be changed. If the glass pane has been pre-bent in the first state on the gravity bending mold, it can be transferred by transition to the second state, simply on the lower Pressbiegeform, without having to be lifted by a tool.
• the gravity bending mold preferably has a frame-shaped bearing surface which is suitable for arranging a glass pane thereon and which has an outer edge and an inner edge.
• the inner edge is facing the center and in the intended use of the glass sheet center.
• the outer edge faces outward and, in the intended use, faces the edge of the window and faces away from the glass pane center.
• the encircling side edge of the glass pane can be arranged on the support surface or also protrude in sections or circumferentially over the support surface.
• the support surface is not completely flat, but partially curved.
• the support surface has an outer, a middle and an inner region.
• the areas are likewise designed like a frame, the outer area enclosing the central area, which in turn encloses the inner area.
• the outer region faces the outer edge
• the inner region faces the inner edge
• the central region is disposed between the outer region and the inner region.
• the areas can be seen in a cross section through the gravity bending form between the outer edge and the inner edge of the support surface, starting from the outer edge in the direction of Inner edge of the outer region, then the middle region and then the inner region is arranged.
• the outer region of the support surface is flat and arranged horizontally.
• the middle region may be flat or slightly curved (preferably convex) and is inclined inwards, ie towards the inner edge.
• the inner region has a relatively strong curvature, which is opposite to the curvature of the glass sheet produced during the gravity bending process.
• the glass sheet is bent during gravity bending so that the lower disk surface is convex and the upper disk surface is concavely curved.
• the inner region of the support surface according to the invention is thus convexly curved, so that the curvature of the second region and the curvature of the glass pane are opposite to each other.
• This shape of the support surface prevents the glass sheet rests only on the edges of the support surface. Instead, the glass sheet is initially flat on the outer area and after the onset of bending flat on the central area. The risk of generating disturbing tool marks can be effectively avoided.
• the glass pane also does not come into contact with the inner edge, which is ensured by the strongly curved inner area. Due to the lack of contact between the inner edge and the glass pane, again tool impressions can be avoided.
• the inner area is more curved than the middle area, so has a smaller radius of curvature.
• the curvature of the inner region is chosen in particular such that the glass pane in the final bent state does not touch the inner edge.
• the radius of curvature in the inner region is at most 200 mm, particularly preferably from 20 mm to 100 mm.
• the radius of curvature in the central region is preferably at least 200 mm, more preferably at least 400 mm. For particularly good results are achieved in conventional disc bends.
• the support surface preferably has a width of 3 cm to 20 cm, more preferably from 5 cm to 15 cm. Such widths are common for bearing surface of gravity bending molds.
• the width of the extension of the support surface along the shortest connection between outer edge and inner edge is referred to, in particular substantially perpendicular to the two edges.
• the width of the middle range is preferably at least 50% the width of the support surface, more preferably at least 70%, most preferably from 80% to 90%.
• the width of the flat outer region of the support surface should be at least 5 mm, preferably from 5 mm to 20 mm.
• the width of the curved inner region of the support surface should be at least 2 mm, preferably from 2 mm to 10 mm.
• the bearing surface of the gravity bending mold can be coated with a tissue, in particular metal-containing tissue. This serves on the one hand the padding to further reduce the risk of tool marks, on the other hand, the thermal insulation to reduce cooling of the glass sheet by the gravity bending mold.
• the invention also includes an arrangement for bending glass sheets comprising the apparatus according to the invention and a glass sheet positioned between the lower press bending mold and the upper press bending mold.
• the glass sheet After press bending, the glass sheet is cooled, which can be done in any way. The cooling can be done on another form, to which the disc is transferred. Cooling may be at ambient temperature or by active cooling.
• the press bending device according to the invention and the method are particularly suitable for the production of curved, tempered glass panes, as are customary for example as side windows or rear windows of motor vehicles. Therefore, in a preferred embodiment, the glass sheet is thermally tempered after being rapidly cooled by bending. After bending, the glass sheet is transferred to a so-called tempering frame, on which it is stored during the tempering process.
• the glass sheet to be bent preferably contains soda-lime glass, as is customary for window panes, but may also contain other types of glass, such as borosilicate glass or quartz glass.
• the thickness of the glass sheet is typically from 0.5 mm to 10 mm, preferably 1 mm to 5 mm. Typical temperatures for bending glass sheets are from 500 ° C to 700 ° C, especially about 650 ° C when bending slices of soda-lime glass.
• the invention also encompasses the use of a device according to the invention for press bending glass sheets for means of transport for transport on land, in the air or on water, preferably for press bending window panes of Rail vehicles or motor vehicles, in particular for press bending of rear windows, side windows or roof windows of passenger cars.
• the glass sheets bent by the method according to the invention are preferably used for locomotion by land, in the air or on water, particularly preferably as window panes of rail vehicles or motor vehicles, in particular as rear windows, side windows or roof panes of passenger cars.
• FIG. 4 shows a cross section through a section of a device according to the invention during press bending
• Fig. 5 shows a cross section through a portion of a lower according to the invention
• Fig. 6 shows a cross section of a tool in which the lower Pressbiegeform with a
• FIG. 7 shows a flow chart of an embodiment of the method according to the invention.
• Figure 1 shows a cross section through a generic device for press bending of glass sheets.
• the device comprises a lower press bending mold 1 with a frame-like contact surface 2 and an upper press bending mold 3 with a full-area active surface, which are arranged opposite one another and are vertically movable relative to one another.
• the glass sheet I to be bent is placed between the press bending molds 1, 3.
• the press bending molds 1, 3 are approximated to each other, so that the glass sheet I is pressed between them and thereby deformed.
• only the side edge S of the glass pane I rests on the contact surface 2 of the lower press bending mold 1.
• Glass pane I and contact surface 2 thus touch only along a circumferential line, which is referred to as contact line 4.
• the entire upper disk surface O is in contact with the effective surface of the upper press bending mold 3.
• the shape of the active surface of the upper press bending mold 3 corresponds to the desired curved shape of the glass pane I.
• Figure 2 shows a cross section through a portion of a device whose lower press bending mold 1 is formed in a conventional manner.
• the contact surface 2 is flat and inclined inwards.
• the glass sheet I is brought into contact with the lower press bending mold 1 and the upper press bending mold 3 (Fig. 2a).
• the contact line 4, along of which the glass sheet I initially comes into contact with the contact surface 2 is referred to as Cleartitleline 4A.
• the glass sheet I is shown here in the initial state plan for the sake of simplicity, but it can also be pre-bent.
• the press bending tools 1, 3 are brought closer to each other, so that the glass pane I is deformed. In this case, the contact line 4 moves inwards starting from the first contact line 4A (FIG. 2b).
• the dashed arrows indicate the movement of the upper press bending mold 3 and the contact line 4 during press bending.
• the press bending molds 1, 3 At the end of the press bending, the press bending molds 1, 3 have reached their final position and the glass pane I has been bent to its final shape (FIG. 2c).
• the contact line 4 reaches its most internal position, which is referred to as pressing line 4B.
• the figure illustrates the disadvantage of conventional lower Pressbiegeformen with flat contact surface 2.
• the risk that the lower disk surface U contacts the contact surface 2 in the region between the pressing line 4 B and the inner edge resulting in Impairment of optical quality.
• the contact could basically be prevented by aligning the contact surface 2 steeper. So that the contact line 4 can nevertheless cover the same horizontal distance, one would have to extend the contact surface 2 but then considerably, with the result that the lower bending mold would be very expansive, especially unwieldy high and would be difficult to integrate into existing plants.
• FIG. 3 shows a plan view of a lower press bending mold 1.
• the frame-shaped contact surface 2 which is bounded by an inner edge 6 pointing to the middle and an outwardly facing outer edge 7.
• the contact of the contact surface 2 with the side edge S of the glass pane I takes place within a region between the frame-shaped first contact line 4A and the pressing line 4B, both of which are circumferentially arranged on the contact surface 2.
• FIG. 4 shows, for comparison with FIG. 2, a cross section through a section of a device with a lower press bending mold 1 according to the invention.
• the contact surface 2 is convexly curved, in particular in the region between the first contact line 4A and the press line 4B.
• the curvature of the contact surface 2 is opposite to the disc curvature. Due to the bending of the distance of the lower portion of the contact surface 2 is increased by the glass pane I, whereby even with glass panes with strong Bends in the edge area a contact of the lower disc surface U can be avoided.
• FIG. 5 shows a cross-section of another lower press bending mold 1.
• the design according to the invention of the contact surface 2 ensures that the lower disk surface does not come into contact with the contact surface 2.
• the lower disk surface and the contact surface 2 thus always include an angle greater than 0 °, which is referred to as a clearance angle ⁇ .
• the clearance angle ⁇ may change during press bending, but always remains greater than 0 °.
• the clearance angle at the pressing line 4B should advantageously be greater than 3 °, for example 7 °.
• the clearance angle between the curved surfaces can be determined exactly by using the tangent planes at the respective contact line 4.
• Figure 6 shows schematically a lower press bending mold 1 and a gravity bending mold 5, which are combined in a common tool.
• the gravity bending mold 5 has a frame-shaped support surface, which is framed by the contact surface 2 of the lower press bending tool 1.
• the press bending mold 1 and the gravity bending mold 5 are vertically displaceable relative to each other, so that it can be set whether the support surface of the gravity bending mold 5 or the contact surface 2 of the Pressbiegeform 1 is arranged higher and consequently can carry the glass pane I.
• the glass sheet I is pre-bent on the higher gravity bending mold 5 (Fig. 6a).
• the bending molds 1, 5 are then displaced relative to one another, with the glass pane I being transferred from the gravity bending mold 5 to the lower press bending mold 1 (FIG. 6b).
• the transfer can be done by moving the gravity bending mold 5 downwards, by moving the press bending mold 1 upwards or by a combination of both.
• Figure 7 shows an embodiment of the method according to the invention with reference to a flow chart.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (13)

Family Cites Families (22)

• 2018
  • 2018-03-15 US US16/604,026 patent/US11203545B2/en active Active
  • 2018-03-15 WO PCT/EP2018/056471 patent/WO2018188888A1/de unknown
  • 2018-03-15 DE DE202018006731.8U patent/DE202018006731U1/de active Active
  • 2018-03-15 KR KR1020197028859A patent/KR102248397B1/ko active IP Right Grant
  • 2018-03-15 RU RU2019135254A patent/RU2742682C1/ru active
  • 2018-03-15 EP EP18711103.4A patent/EP3609849A1/de not_active Withdrawn
  • 2018-03-15 BR BR112019013410-7A patent/BR112019013410A2/pt not_active Application Discontinuation
  • 2018-03-15 MX MX2019012146A patent/MX2019012146A/es unknown
  • 2018-03-15 CN CN201880000591.9A patent/CN109071304B/zh not_active Expired - Fee Related
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  • 2018-03-15 JP JP2019551630A patent/JP6886039B2/ja active Active
  • 2018-03-15 CA CA3058805A patent/CA3058805C/en active Active
• 2019
  • 2019-07-18 CO CONC2019/0007762A patent/CO2019007762A2/es unknown

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