Wedge shaped glass and methods of forming wedged glass

• US 20030215610A1
• Filed: 03/25/2003
• Published: 11/20/2003
• Est. Priority Date: 04/05/2002
• Status: Active Grant

• Current Assignee: Vitro Flat Glass LLC (Compagnie De Saint-Gobain)
• Original Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Inventors: Zahler, James A., DiGiampaolo, Gerald, Garefino, Jennifer M.
• Granted Patent: US 7,122,242 B2
• Time in Patent Office: Days
• US Class Current: 428/156
• CPC Class Codes: B32B 17/10036 comprising two outer glass sheets
• CPC Class Codes: B32B 17/10155 Edge treatment or chamfering
• CPC Class Codes: B32B 17/10165 Functional features of the laminated safety glass or glazing
• CPC Class Codes: B32B 17/10293 Edge features, e.g. inserts or holes
• CPC Class Codes: B32B 17/1066 imparting a tint in certain regions only, i.e. shade band
• CPC Class Codes: B32B 17/10761 containing vinyl acetal
• CPC Class Codes: C03B 18/06 using mechanical means, e.g. restrictor bars, edge rollers
• CPC Class Codes: Y10T 428/24479 including variation in thickness
• CPC Class Codes: Y10T 428/24488 Differential nonuniformity at margin
• CPC Class Codes: Y10T 428/24612 Composite web or sheet
• CPC Class Codes: Y10T 428/24777 Edge feature
• CPC Class Codes: Y10T 428/2495 Thickness [relative or absolute]
• CPC Class Codes: Y10T 428/24967 Absolute thicknesses specified
• CPC Class Codes: Y10T 428/3163 Next to acetal of polymerized unsaturated alcohol [e.g., formal butyral, etc.]

Abstract

A glass sheet includes a first edge, an opposing, second edge, and an intermediate location between the first edge and second edge. The glass sheet has a first portion extending between the first edge and the intermediate location and a second portion extending between the intermediate portion and the second edge, wherein the first portion has a generally uniform thickness and the second portion has a varying thickness. The thickness of the second portion can either increase or decrease from the intermediate location to the second edge. A laminated transparency incorporating the glass sheet as well as a method of forming a glass ribbon having a changing thickness profile along at least a portion of the width of the ribbon are also disclosed.

Claims

1. A glass sheet comprising:

a first edge;

an opposing, second edge; and

an intermediate location between the first edge and second edge, wherein the glass sheet has a first portion extending between the first edge and the intermediate location and a second portion extending between the intermediate portion and the second edge and further wherein the first portion has a generally uniform thickness and the second portion has a varying thickness.

2. The glass sheet as in claim 1, wherein the second portion is generally wedge shaped.

3. The glass sheet as in claim 1, wherein the thickness of the second portion increases from the intermediate location to the second edge.

4. The glass sheet as in claim 1, wherein the thickness of the second portion decreases from the intermediate location to the second edge.

5. The glass sheet as in claim 1, wherein the thickness of the second portion changes uniformly.

6. The glass sheet as in claim 1, wherein the second portion of the glass sheet has a wedge angle ranging from 0.01 to 0.04 degrees.

7. The glass sheet as in claim 6, wherein the second portion of the glass sheet has a wedge angle ranging from 0.02 to 0.035 degrees.

8. A laminated transparency, comprising:

a first glass ply having a first edge, an opposing second edge, and an intermediate location between the first edge and second edge, wherein the first glass ply has a first portion extending between the first edge and the intermediate location and a second portion extending between the intermediate portion and the second edge, and further wherein the first portion has a generally uniform thickness and the second portion has a thickness that decreases from the intermediate location to the second edge of the first glass ply;

a second glass ply; and

an interlayer material securing the first glass ply to the second glass ply.

9. The transparency as in claim 8, wherein a portion of the transparency where the second portion of the first ply is secured to the second ply has a wedge angle ranging from 0.01 to 0.04 degrees.

10. The transparency as in claim 9, wherein the portion of the transparency where the second portion of the first ply is secured to the second ply has a wedge angle ranging from 0.02 to 0.035 degrees.

11. The transparency as in claim 8, wherein the second glass ply has a first edge generally aligned with the first edge of the first ply, an opposing second edge generally aligned with the second edge of the first ply, and an intermediate location between the first edge and second edge of the second ply, and the second glass ply has a first portion extending between the first edge of the second ply and the intermediate location of the second ply and a second portion extending between the intermediate portion of the second ply and the second edge of the second ply, and further wherein the first portion of the second ply has a generally uniform thickness and the second portion of the second ply has a thickness that decreases from the intermediate location of the second ply to the second edge of the second glass ply.

12. The transparency as in claim 8, wherein the laminate is an automotive windshield.

13. The transparency as in claim 12, wherein at least a portion of the interlayer material includes a wedge shaped thickness profile.

14. The transparency as in claim 12, wherein the windshield has arcuate, opposing upper and lower edges, and the interlayer material includes a shade band that substantially parallels the upper arcuate edge of the windshield.

15. A method of forming a glass ribbon having a changing thickness profile along at least a portion of the width of the ribbon, comprising:

delivering a stream of molten glass to a pool of molten metal within a longitudinally extending forming chamber;

applying an attenuating force to the glass to draw the glass through the forming chamber at a downstream velocity that is generally uniform across the glass to form a ribbon comprising a center portion and a longitudinal edge portion extending between the center portion and a longitudinal edge of the ribbon; and

changing the downstream velocity of selected portions of the ribbon so as to change the attenuation of the ribbon such that the center portion of the ribbon has a generally uniform thickness profile across the width of the ribbon and the longitudinal edge portion has a varying thickness profile across the width of the ribbon with a first thickness along the center portion that generally corresponds to the uniform thickness of the central portion and a second thickness along the longitudinally edge of the ribbon different from the first thickness.

16. The method of claim 15, wherein the longitudinal edge portion has a generally wedged shaped thickness profile across the width of the ribbon.

17. The method of claim 15, wherein the changing comprises engaging opposing longitudinally extending edges of the ribbon with a tractive force to change the attenuation of the glass along the longitudinal edge portions as the glass is drawn through the forming chamber.

18. The method of claim 17, wherein the engaging comprises contacting an upper surface of the ribbon with a rotating roll of an edge roll machine.

19. The method of claim 18, wherein the engaging further comprises increasing the rotational speed of the roll to decrease the attenuation of the longitudinal edge portion as it is drawn through the forming station so that the different thickness of the ribbon along the longitudinal edge is greater than the uniform thickness.

20. The method of claim 18, wherein the engaging further comprises decreasing the rotational speed of the roll to increase the attenuation of the longitudinal edge portion as it is drawn through the forming station so that the different thickness of the ribbon along the longitudinal edge is less than the uniform thickness.

21. The method of claim 15, wherein changing comprises changing viscosity of selected portions of the ribbon.

22. The method of claim 21, wherein viscosity changing comprises decreasing the viscosity of the center portion of the ribbon as compared to the longitudinal edges so that the different thickness of the ribbon along the longitudinal edge is greater than the uniform thickness.

23. The method of claim 21, wherein viscosity changing comprises increasing the viscosity of the center portion of the ribbon as compared to the longitudinal edges so that the different thickness of the ribbon along the longitudinal edge is less than the uniform thickness.