Bending glass sheets to a tapered line of bend
AssigneePPG Industries, Inc.
InventorsThomas J. Reese, Melvin W. Tobin, James R. Mortimer
Life of this patent
Estimating the term…
Abstract
Glass sheets are bent along a line which is sharply creased at one end and gently curved at the opposite end. Localized heating along the line is provided by an electrically heated ribbon mounted above the glass so as to maintain a constant spacing between the glass and the ribbon at one end of the line, while the spacing at the other end of the line gradually increases as bending progresses.
Claims13
A method of bending a glass sheet along a line of bending that has a creased appearance at a first end and a gently bent, uncreased appearance at a second end, comprising:
- supporting a flat glass sheet on an outline bending mold provided with an upper shaping surface conforming in elevation to the desired contour for the bent glass sheet;
- supporting a ribbon of electroconductive material above the upper surface of the glass sheet in vertical alignment with said line of bending;
- heating the glass sheet to near its softening point;
- passing electric current through said electroconductive ribbon so as to heat said line of bending to a temperature higher than that of the remainder of the sheet, whereby the glass sheet bends along said line of bending and sags into conformity with the contour of the bending mold;
- and as the glass sags, increasing the space between the electroconductive ribbon and the glass at said second end of the line of bending to a greater degree than any increase in the space between the electroconductive ribbon and the glass at said first end of the line of bending, so that at the conclusion of the bending the space at said first end is smaller than the space at said second end.
An apparatus for bending a glass sheet along a line of bending that has a creased appearance in one portion and a gently bent uncreased appearance in another portion comprising:
- a frame supporting an outline bending mold which includes a pair of shaping rails extending along opposite sides of the mold, one of said rails having an upper surface provided with a "V" shaped configuration, and the other shaping rail provided with an upper surface of gently curvature, the upper extremities of said shaping rails defining a substantially horizontal support plane for a sheet of flat glass to be bent;
- a pair of electrodes supported on said frame on opposite sides of the mold, spaced laterally outward from said shaping rails, said electrodes having means for supporting a ribbon of electroconductive material above said shaping rails in vertical alignment with the "V" in said one shaping rail, the first of said electrodes being located adjacent said gently curved shaping rail and having its ribbon supporting means at an elevation above said glass support plane, the second of said electrodes being located adjacent the "V" shaped shaping rail and having its ribbon supporting means at an elevation below said glass support plane;
- and means for maintaining said ribbon in tension between said electrodes.
Dependencies are inferred from the claim text.