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US 4,056,379 AGranted
Forming V bends in glass sheets by press bending
AssigneePPG Industries, Inc.
InventorsJoseph B. Kelly, Kenneth A. Gibson
Life of this patent
Estimating the term…
Abstract
Heat-softened glass sheets may have sharp bends imparted thereto by pressing between complementary molds when preceded by localized heating along the intended line of the sharp bend. The localized heat is applied along the line by means of electrical resistance heating through the glass immediately prior to the pressing step.
Claims12
A method of bending a glass sheet into a shape which includes a line of sharp bending about which the radius of curvature is less than 8 inches, comprising the steps of:
- applying an electroconductive stripe onto a surface of a sheet of glass along a line of intended sharp bending;
- heating the sheet of glass in a heated enclosure to an overall temperature suitable for bending;
- removing the sheet of glass from said heated enclosure and passing electric current through the stripe so as to heat the line of intended sharp bending to a temperature higher than said overall temperature of the glass sheet;
- and
- bending the sheet of glass to the desired curvature, including said sharp bend of less than 8 inches radius, by pressing it between two shaping members having shaping surfaces of complementary curvature.
2 more elements
An apparatus for bending a sheet of glass comprising:
- a heated enclosure, including means to heat a sheet of glass to a softened condition suitable for bending;
- a pair of opposed shaping members located outside said furnace and having complementary shaping surfaces conforming to the desired shape for the glass, including a line of sharp bending about which the radius of curvature is less than 8 inches;
- means to bring the shaping members into pressing contact against opposite surfaces of a glass sheet supported therebetween;
- means to convey a glass sheet into and out of said heated enclosure and into and out of pressing position between said shaping members;
- a pair of electrodes located on opposite sides of the pressing position, said electrodes having means associated therewith for moving the electrodes into and out of contact with opposite edges of a glass sheet when the sheet is located between said pressing members;
- and
- means for supplying electric current to the electrodes so that electric current may be passed along the line of sharp bending in the glass sheet while the glass sheet is positioned between the shaping members.
4 more elements
Dependencies are inferred from the claim text.