Method and apparatus for shaping moving glass sheets by sagging followed by roll pressing
AssigneePPG Industries, Inc.
InventorsStephen J. Schultz, Terry L. Wolfe
Life of this patent
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Abstract
This invention relates to shaping glass sheets by roll forming to either simple or complex curvatures about a single axis of bending or to compound curvatures comprising components of curvature about mutually perpendicular axes of bending by a controlled, repeatable program of roll forming without causing the glass sheets to stop their forward movement during their shaping. The apparatus used to perform this process has a minimum of moving parts, thus minimizing maintenance problems and reducing downtime for maintenance and repair.
Claims24
A method of shaping a glass sheet comprising
- heating the sheet to its deformation temperature in a furnace,
- conveying said sheet along a path of travel beyond said furance while said sheet remains hot over a series of rotating forming rolls shaped to transverse elevational shape to sag the sheet by gravity to conform approximately to the transverse elevational shape of the last forming roll in said series, and
- inhibiting the formation of tip curl in the vicinity of the transverse side edge portions of said gravity sagged sheet by pressing said sheet between a plurality of pairs of additional rotating forming rolls of complementary transverse elevational shape arranged with diminishing space between the rolls of each successive pair of said additional rotating forming rolls along said path of travel wherein the space between the last of said pairs of additional rotating forming rolls barely exceeds the thickness of said glass sheet.
A method of shaping a glass sheet while at deformation temperature comprising passing said sheet between pairs of rotating forming rolls of complementary transverse elevational shape arranged with diminishing space between the rolls of each successive pair along a path of travel including a downstream pair of rolls spaced from one another by a distance that barely exceeds the thickness of said glass sheet.
Apparatus for shaping a glass sheet comprising a furnace and a roll forming section, said roll forming section comprising an upstream portion having a plurality of rotatable forming rolls shaped in transverse elevation and a downstream portion comprising a plurality of pairs of closely spaced, rotatable forming rolls of complementary shape arranged along a path of travel, the space between the rotatable forming rolls of said plurality of pairs diminishing in a downstream direction along said path of travel.
Dependencies are inferred from the claim text.