Method of and apparatus for strengthening edges of one or more glass sheets
View Patent ↗A furnace includes a section defined as a heating section capable of attaining a predetermined temperature, the heating section having an entrance end and an exit end; a section defined as a cooling section capable of having a temperature gradient from entrance end of the cooling section to exit end of the cooling section, the entrance end of the cooling section mounted in a fixed relationship to the exit end of the heating section; a section defined as an edge cooling section between the exit end of the heating section and the entrance end of the cooling section; and an edge cooling device positioned in the edge cooling section relative to a predetermined area, and capable of cooling at least selected peripheral portions of the predetermined area at a faster rate than center portions of the predetermined area.
1. A glass sheet comprising:
a first major surface, an opposite second major surface, a peripheral edge circumscribing the sheet and joining the first and the second major surfaces, and
a first length of the peripheral edge less than perimeter of the peripheral edge; a second length of the peripheral edge less than the perimeter of the peripheral edge, and a third length of the peripheral edge less than the perimeter of the peripheral edge, wherein the third length is between the first and the second lengths, and the first length has an edge compression greater than the edge compression of the third length, and the second length has an edge compression greater than the edge compression of the third length.
2. The glass sheet according to claim 1 wherein the first length has an edge compression of at least 3,000 psi (20.7×10 6 Pa) (211 kilograms per square centimeters), and the third length has an edge compression of less than 3,000 psi (20.7×10 6 Pa) (211 kilograms per square centimeters).
3. The glass sheet according to claim 2 wherein the edge compression of the first and the second lengths are each in the range of 3,000-5,000 pounds per square inch (20.7-34.5×10 6 Pa) (211-352 kilograms per square centimeter) terminating a distance of 0.125 inch (0.32 cm) from the peripheral edge.
4. The glass sheet according to claim 1 further comprising a fourth length of the peripheral edge less than the perimeter of the peripheral edge, the fourth length between the first and the second lengths, and opposite to the third length, wherein the first length has an edge compression greater than the edge compression of the fourth length, and the second length has an edge compression greater than the edge compression of the fourth length.
5. The glass sheet according to claim 4 wherein the second length is opposite to the first length, and the fourth length is opposite to the third length, wherein the first and the second lengths have an edge compression of at least 3,000 psi (20.7×10 6 Pa) (211 kilograms per square centimeters), and the third and the fourth lengths have an edge compression of less than 3,000 psi (20.7×10 6 Pa)) (211 kilograms per square centimeters).
6. The glass sheet according to claim 1 , wherein the glass sheet is part of a transparency selected from transparencies for above water, below water, air and/or space vehicles; automotive side windows, automotive back windows, multiple glazed windows for homes, buildings and temperature controlled storage compartments having a viewing area.
7. The glass sheet according to claim 1 , wherein the glass sheet is a shaped glass sheet.
8. The glass sheet according to claim 7 , wherein the shaped glass sheet is a first shaped glass sheet of a laminate and the laminate further comprises a second shaped glass sheet adhered to the first shaped glass sheet by a plastic interlayer sheet.
9. The glass sheet according to claim 8 , wherein the laminate is an automotive windshield.
10. The glass sheet according to claim 9 , wherein an inner surface of at least one of the sheets of the laminate has an electroconductive coating.
11. The glass sheet according to claim 9 , wherein an inner surface of one of the sheets of the laminate has a solar control coating.
12. The glass sheet according to claim 1 , wherein the glass sheet is a first glass sheet of a laminate and the laminate further comprises a second glass sheet adhered to the first glass sheet by a plastic interlayer sheet, wherein the second sheet comprises:
a first major surface, an opposite second major surface, a peripheral edge circumscribing the second sheet and joining the first and the second major surfaces of the second sheet, and
a first length of the peripheral edge less than perimeter of the peripheral edge; a second length of the peripheral edge less than the perimeter of the peripheral edge, and a third length of the peripheral edge less than the perimeter of the peripheral edge, wherein the third length is between the first and the second lengths, and the first length has an edge compression greater than the edge compression of the third length, and the second length has an edge compression greater than the edge compression of the third length.
13. The glass sheet according to claim 12 , wherein the first and second glass sheets of the laminate are shaped glass sheets.
14. The glass sheet according to claim 13 , wherein the laminate is an automotive windshield.
15. The glass sheet according to claim 12 , wherein the second sheet further comprising a fourth length of the peripheral edge less than the perimeter of the peripheral edge of the second sheet, the fourth length between the first and the second lengths of the second sheet, and opposite to the third length of the second sheet, wherein the first length of the second sheet has an edge compression greater than the edge compression of the fourth length of the second sheet, and the second length of the second sheet has an edge compression greater than the edge compression of the fourth length of the second sheet.
16. The glass sheet according to claim 15 wherein the first length of the first and the second sheets are aligned with one another; the second length of the first and the second sheets are aligned with one another; the third length of the first and the second sheets are aligned with one another, and the fourth length of the first and the second sheets are aligned with one another.
17. The glass sheet according to claim 16 , wherein the first and second lengths of the first and second sheets each have an edge compression of at least 3,000 psi (20.7×10 6 Pa), and the second, fourth, sixth and eighth areas each have a strength of less than 3,000 psi (20.7×10 6 Pa) (211 kilograms per square centimeters).
18. The glass sheet according to claim 16 wherein the edge compression of the first and the second lengths of the first and second sheets are each in the range of 3,000-5,000 pounds per square inch (20.7-34.5×10 6 Pa) (211-352 kilograms per square centimeter) terminating a distance of 0.125 inch (0.32 cm) from the peripheral edge.
19. A glass sheet comprising:
a first major surface, an opposite second major surface, a peripheral edge circumscribing the sheet and joining the first and the second major surfaces;
an edge compression in the range of 3,000-5,000 pounds per square inch (20.7-34.5×10 6 Pa) (211-352 kilograms per square centimeter), the edge compression starting at the peripheral edge of the sheet and terminating a distance of 0.125 inch (0.32 cm) from the peripheral edge, and
an annealed center portion having a boundary line within the peripheral edge and spaced from the peripheral edge a distance of 0.125 inch (0.32 cm).