US 7,024,889 B2Granted

Method and apparatus for bending glass sheets

AssigneeCentral Glass Company, Limited

InventorsMasami Nishitani, Makoto Shinohara

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Abstract

For bending a glass sheet so that the glass sheet has a compound curvature, an apparatus comprises a furnace including hearth beds on a bed support and a quenching unit provided with upper and lower air blowers. The final hearth bed may have a top surface with a simple curvature, be provided with one upstream corner cut away thereby defining a cut surface section and arranged in such a manner that the cut surface section is nearly parallel to the hearth bed adjacent to the final hearth bed. Alternatively, the final hearth bed may have a top surface with a compound curvature, so that the glass sheet is bent under the conditions set by controlling a temperature in a downstream part of the furnace, adjusting the inclination of the lower air blower and/or rotating final hearth bed so as to reverse the upstream and downstream ends thereof.

Claims14

Dependent claims

An apparatus for bending a glass sheet, comprising:

a furnace including therein a bed support that has a support surface made flat and horizontal throughout its entire length, a plurality of hearth beds and a final hearth bed both having flat bottom portions and placed on the bed support with the flat bottom portions and the support surface contacted with each other, the plurality of hearth beds having top surfaces curved in a direction perpendicular to a conveyance direction with curvature radii that gradually decrease as located more downstream, the final hearth bed being located downstream of the plurality of hearth beds and only the final hearth bed having a top surface curved in both the conveyance direction and the direction perpendicular to the conveyance direction so as to be upwardly convex, the furnace having a plurality of temperature zones located over the plurality of hearth beds and the final hearth bed and capable of controlling a temperature in each temperature zone;
a quenching unit provided with upper and lower air blowers and arranged downstream of the final hearth bed, the lower air blower having a top surface adjacent to the top surface of the final hearth bed in such a manner that a tangent to an upstream end portion of the top surface of the lower air blower forms an angle α with respect to a tangent to a downstream end portion of the top surface of the final hearth bed and is inclined downwardly with respect to a horizontal plane;
and
a conveyor that conveys the glass sheet in the conveyance direction through the furnace and the quenching unit.

1 more element

A method for bending a glass sheet, comprising the steps of:

placing a plurality of hearth beds and a final hearth bed on a bed support in a furnace with flat bottom portions of the plurality of hearth beds and of the final hearth bed and a support surface of the bed support contacted with each other, the support surface of the bed support being made flat and horizontal throughout its entire length, the plurality of hearth beds having top surfaces curved in a direction perpendicular to a conveyance direction with curvature radii that gradually decrease as located more downstream, and only the final hearth bed being placed downstream of the plurality of hearth beds and having a top surface curved in both the conveyance direction and the direction perpendicular to the conveyance direction so as to be upwardly convex, the furnace having a plurality of temperature zones located over the plurality of hearth beds and the final bed and divided into an upstream part and a downstream part, and the furnace being capable of controlling a temperature in each temperature zone;
arranging a quenching unit provided with upper and lower air blowers downstream of the final hearth bed in such a manner that the lower air blower has a top surface adjacent to the top surface of the final hearth bed;
setting conditions for bending the glass sheet into a shape having a desired compound curvature, the step of setting comprising positioning the upper and lower air blowers in such a manner that a tangent to an upstream end portion of the top surface of the lower air blower forms an angle a with respect to a tangent to a downstream end portion of the top surface of the final hearth bed and is downwardly inclined with respect to a horizontal plane;
heating the glass sheet in the furnace while conveying the glass sheet in the conveyance direction over the plurality of hearth beds and the final hearth bed, thereby bending the glass sheet so that the glass sheet has the desired compound curvature;
and
quenching the glass sheet in the quenching unit while conveying in the conveyance direction over the lower air blower.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/119,705Filed 11 Apr 2002
Priority: JP 2001-11598413 Apr 2001
Published: US 2002/0148254 A117 Oct 2002
Granted: 11 Apr 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

C03B 27/0431
For bent glass sheets: the quench unit being adapted to the bend of the sheet
C03B 23/035
By bending: using a gas cushion or by changing gas pressure, e.g. by applying vacuum or blowing for supporting the glass while bending
C03B 27/048
For flat or bent glass sheets being in a horizontal position: on a gas cushion
C03B 29/12
Glass sheets: being in a horizontal position on a fluid support, e.g. a gas or molten metal