Ppg Industries, Inc.

Joseph J Fisher

Thomas J Reese

Glass sheets are positioned on a shaping rail of an outline shaping mold form movement through a heating lehr and subsequent preliminary sag bending. The mold with the glass sheet supported thereon is positioned between a pair of vertically aligned pressing molds. The lower mold includes a full surface press face corresponding to the final desired curvature of the glass sheet to be shaped. The upper mold includes a peripheral shaping surface and a chamber defined by the shaping surface. After the lower mold lifts the glass sheet off the outline mold and into engagement with the upper mold, gas in the chamber is pressurized to urge those portions of the glass not contacted by the upper mold against the press face of the lower mold.

In-lehr glass sheet press bending using pressurized gas

Apparatus for shaping glass sheets to a complicated shape including a longitudinal component of bend and a complicated transverse component of bend within a tunnel-like lehr. An outline mold with guides for aligning one or more glass sheets for proper orientation and alignment thereon supports the glass while the glass is bent by gravity sagging to provide a longitudinal component of bend and to deliver the sag bent glass to a position between upper and lower pressing molds having complementary shaping surfaces conforming to a complicated bend including a complicated transverse bend component. Special alignment means are provided to orient and align the outline mold relative to said pressing molds so that the lower pressing mold can lift the sag bent glass off the outline mold into engagement with the upper pressing mold to impress the transverse bend component and return the glass with its complicated shape to the outline mold for controlled cooling and removal from the lehr. When two glass sheets are shaped simultaneously in this manner, they conform exactly to the shape of each other so closely that they can be laminated readily to form a laminated windshield of complicated shape for installation in exact registration with a shaped mounting frame of a vehicle. The upper pressing mold may be omitted in cases where thin glass sheets are bent to relatively shallow curvatures which may involve complicated shapes and/or outlines.

Mold alignment means for glass sheet shaping apparatus

When glass sheets are shaped by a bending method in which the glass is first shaped to a longitudinal component of bend by gravity sagging onto an outline mold followed by press bending against a solid lower shaping mold to complete the bend which includes a complicated transverse component of bend, a particular speed cycle is provided to lift and lower the lower shaping mold to minimize the duration of the shaping cycle and to minimize the chance of misaligning the glass relative to the outline mold during transfer of the glass from the outline mold to the lower shaping mold and its return to the outline mold. This speed cycle includes a rapid initial lifting speed and final lowering speed of the lower shaping mold while it is out of contact with the glass and a lower speed of lifting and lowering when the lower shaping mold contacts and supports the glass.

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Oakmont, PA, United States of America

Joseph J Fisher