Prior art

The following US patents are cited within US8627684 as describing the fusion process, which forms the background for the invention:

1. US Patent 3,338,696

• Full Citation: US3338696A, "Sheet forming apparatus"
• Publication/Filing Date: Published August 29, 1967; Filed May 6, 1964
• Brief Description: This patent describes a sheet forming apparatus for the production of thermoplastic sheet material, particularly glass, utilizing an overflow trough (isopipe) where molten material flows down two sides and fuses at a root to form a sheet. The patent details methods for controlling the uniformity of flow and thickness across the width of the sheet.
• Potential Anticipation (35 U.S.C. § 102): This patent describes the fundamental fusion process for forming a glass sheet, including the initial melting of batch materials and the formation of a glass sheet from an isopipe. Therefore, it is highly relevant to the general steps of "melting batch materials and forming the glass sheet" in independent claim 14 and the system components for "melting batch materials and forming molten glass" and "an isopipe for receiving the molten glass and forming a glass sheet" in independent claim 19 of US8627684.

2. US Patent 3,682,609

• Full Citation: US3682609A, "Controlling thickness of newly drawn glass sheet"
• Publication/Filing Date: Published August 8, 1972; Filed October 6, 1969
• Brief Description: This patent addresses controlling the thickness of a newly drawn glass sheet, particularly by minimizing variations in temperature profile across the width of the sheet, which can lead to objectionable thickness variations. It details an apparatus using fluid conduit tubes or air jets positioned across the width of the sheet to control gaseous discharge against the glass surface.
• Potential Anticipation (35 U.S.C. § 102): Similar to US3338696A, this patent describes improvements to the fusion process related to the quality of the formed glass sheet. It is relevant to the broader context of manufacturing and drawing a glass sheet, as recited in independent claim 14 and independent claim 19 of US8627684. While it addresses controlling aspects (like thickness), its focus is on temperature profile and air jets rather than the specific pull roll apparatus and tension control mechanisms (stub rolls, downtilt, splay, torque/velocity control) claimed in US8627684.