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
  • C03B23/025—Re-forming glass sheets by bending by gravity
  • C03B23/0258—Gravity bending involving applying local or additional heating, cooling or insulating means
• • 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
  • C03B23/03—Re-forming glass sheets by bending by press-bending between shaping moulds
  • C03B23/0302—Re-forming glass sheets by bending by press-bending between shaping moulds between opposing full-face 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
  • C03B23/035—Re-forming glass sheets by bending using a gas cushion or by changing gas pressure, e.g. by applying vacuum or blowing for supporting the glass while bending
  • C03B23/0352—Re-forming glass sheets by bending using a gas cushion or by changing gas pressure, e.g. by applying vacuum or blowing for supporting the glass while bending by suction or blowing out for providing the deformation force to bend the glass sheet
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B27/00—Tempering or quenching glass products
  • C03B27/012—Tempering or quenching glass products by heat treatment, e.g. for crystallisation; Heat treatment of glass products before tempering by cooling
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B29/00—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins
  • C03B29/04—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins in a continuous way
  • C03B29/06—Reheating glass products for softening or fusing their surfaces; Fire-polishing; Fusing of margins in a continuous way with horizontal displacement of the products
  • C03B29/08—Glass sheets

Definitions

• the present invention relates to a method for bending and tempering glass sheets, particularly automotive backlight and side windows, wherein a glass sheet supported by a ring mould is heated to a bending temperature and the glass sheet is allowed to bend gravitational ly close to a correct bending shape.
• the increase of temperatur after a bending operation involves the problem of how to retain a desired bending shape while one surface of a glass sheet is free for applying the heating effect to a glass sheet.
• a problem is the positioning of a glass sheet between the transfers. This positioning problem does not occur if a glass sheet is already positioned prior to a heating operation directly onto a ring mould.
• An object of the invention is to provide a method for bending and tempering glass sheets in a manner that the bent shape of a glass sheet can be retained and controlled even as the temperature of a bent glass sheet is equalized and if necessary heated to a sufficient temperature for tempering.
• a glass sheet is placed and simultaneously properly positioned upon a ring mould 6 in a loading station, located at the inlet end of an upper conveyor track 1.
• Moulds 6 are carried in wagons 3 whose front walls 4 separate successive preheating stations 5 from each other. Between the stations there may also be a gate, which is opened and closed. Wagons 3, 4 are advanced by one wagon length at a time on track 1.
• a piece of glass 7 placed upon ring mould 6 is sequentially carried through preheating and pre-bending stations 5.
• the glass is heated with electric resistances and possibly also by blasting hot air to the top and bottom surfaces of said glass.
• the hot air is aspirated through openings 12 included in the lower furnace section and blasted into stations 5 through orifices 13. If necessary, it is possible to employ heaters for heating the blasting air.
• a glass sheet 7 is heated with electric resistance elements 14 to a temperature sufficient for achieving gravitational pre-bending close to a final bending shape.
• the glass is carried into a bending station 17 located at the outlet end of a furnace, wherein a glass sheet supported by ring mould 6 is approached by an overhead full-face mould 15, the shape of whose surface 1 substantially corresponds to a desired final bending shape. It is possibly necessary to anticipate the bendin occurring during transfers and, thus, the surface shape o mould 15 is slightly "short".
• Mould 15 is double- channeled in a manner that the orifices in its surface ca be simultaneously used for blasting and aspiration.
• Wagon 3, along with its ring mould 6, is lowered down by means of a hoist 10 and it returns along track 2 through the bottom of a furnace to the inlet end into the loading station by lifting it there by means of a hoist 11.
• wagon 3, along with its mould 6, be first carried backwards in its traveling direction and only then lowered down.
• a bent glass sheet can be heated from below by means of fixed heating elements while the glass sheet is supported by the overhead full-face mould 15. Another possibility is to effect the equalization of temperature exclusively by means of air circulated through the mould.
• the full mould 15 is ceramic and the shape of its surface 16 corresponds substantially to the final bending shape of glass 7. Inside the full mould there is a double manifold, opening to surface 16 with nozzle orifices for producing on the glass surface both vacuum and blasting. When a glass sheet is retained as supported by full mould 15 with a negative pressure, the glass reaches and retains precisely its final shape. With the most complicated shapes, wherein the vacuum of overhead full mould 15 is not sufficient to achieve a final shape, a further pressing is effected from below by means of a lower partial or full-face mould or by means of a combination of a frame piece and its associated press, whereby the outermost edge of glass is pressed against overhead full mould 15.
• the purpose of blasting is to equalize temperature differences in glass and to heat it to a tempering temperature.
• the heat tempering can also be effected by using hot air blasted through the blasting orifices of mould 15. It is also possible to employ to such heating devices which can be shifted aside from below said mould 15, so that a glass sheet 7 can be lifted and lowered by means o a vertically movable mould.
• a station 17 can be provided with horizontal' guides 9 that can also be use for manipulating a special tempering frame 8' between station 17 and an external tempering station.
• the heating devices have been shifted onto the side of statio 17, either said tempering frame 8' along guides 9 or said tempering frame 8 along track 1 is brought to a position below said mould 15.
• a heated piece of glass 7 is shifted from full mould 15 onto tempering frame 8 ' or 8 brought therebelow.
• the temperin frame 8' can be intended e.g. for side windows and the tempering frame 8 for backlights.
• the tempering frame 8 is used to carry the glass quickly to a chiller 19.
• the tempered piece of glass is lifted from tempering frame 8 by means of an overhead pick-up 20 onto a roll conveyor 22, from which the glass travels through an after-cooler 21 to an unloading station 23.
• a stationary mould 15 can be adapted to approach the glass by lifting said wagon 3 by means of hoist 10. It is also possible that heat tempering is effected in a heat- temperi ' ng station arranged between stations 17 and 19, whereby said mould 15 must be made horizontally movable between bending station 17 and the heat-tempering station. In this case, as well, the heating elements (e.g. lower resistances) can be stationary in position. If the heat tempering is' only effected by the hot-air blasting of mould 15, no separate heat-tempering station or movable heating elements are required.

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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 (3)

Publications (1)

Family

ID=8533194

Family Applications (1)

Country Status (4)

Families Citing this family (15)

Family Cites Families (2)

• 1991
  • 1991-09-27 FI FI914550A patent/FI89038C/fi active
• 1992
  • 1992-09-25 EP EP92919831A patent/EP0605519A1/en not_active Ceased
  • 1992-09-25 JP JP5505821A patent/JPH06510736A/ja active Pending
  • 1992-09-25 WO PCT/FI1992/000257 patent/WO1993006052A1/en not_active Application Discontinuation

Non-Patent Citations (1)

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