Method and apparatus for reshaping glass sheets
AssigneePPG Industries, Inc.
InventorVaughn R. Imler
Life of this patent
Estimating the term…
Abstract
Method and apparatus for shaping one or more glass sheets by gravity sag bending to a shape including one or more sharp bends by combining overall heating and localized heating using one or more electroconductive heating ribbons and guiding means to locate the ribbons below the shaping surface of a sectionalized mold in positions which do not interfere with loading or unloading of glass sheets on said mold.
Claims21
Apparatus for shaping a glass sheet to a shape that includes a sharp bend extending across a dimension of said sheet by the gravity sag method comprising a plurality of rigid, metal shaping rails disposed in end-to-end relation to define an outline shaping mold having an upper shaping surface conforming to the shape desired slightly inward of the margin of a glass to be shaped thereon, each of said shaping rails having an upper edge surface providing a different portion of said upper shaping surface and including an end shaping rail having inner ends defining an end section of said mold and a pair of longitudinally extending, transversely spaced shaping rails defining a main section of said mold, means supporting said end shaping rail for pivoting relative to said main mold section between an open mold position wherein the inner ends of said end shaping rail are separated from a pair of transversely spaced ends of said elongated shaping rails and a closed mold position where said inner ends of said end shaping rail are closely spaced from said pair of ends of said elongated shaping rails, the ends of said elongated shaping rails providing supports for a flat glass sheet intermediate its ends when said sheet is mounted on said mold for bending and providing supports for the glass sheet after the latter is bent adjacent the inner ends of said end shaping rail, an elongated, electroconductive ribbon extending across the space between said elongated shaping rails entirely below said upper shaping surface along a line in close adjacency to the pair of flat glass supporting ends of said elongated shaping rails, guiding means located laterally outside each of said elongated shaping rails and having a surface engaging said ribbon to control the vertical position of said flexible electroconductive ribbon to one below said shaping surface, a pair of electrodes comprising an electrode laterally outside each of said guiding means for electrical connection with the ends of said ribbon and means carried in electrically insulating relation to said mold and its support adapted to couple said pair of electrodes to a source of electrical energy, said apparatus being clear of any structural element above the area enclosed by said rigid metal shaping rails to facilitate loading and unloading of a glass sheet relative to said mold.
Apparatus for shaping a glass sheet to a shape that includes a sharp bend extending across a dimension of said sheet by the gravity sag method comprising a plurality of rigid metal shaping rails disposed in end-to-end relation to define an outline shaping mold having an upper shaping surface conforming to the shape desired slightly inward of the margin of a glass sheet to be shaped thereon, each of said shaping rails having an upper edge surface providing a different portion of said upper shaping surface and including an end shaping rail defining an end section of said mold and a pair of longitudinally extending, transversely spaced shaping rails defining a main section of said mold, means supporting said end shaping rail for pivoting relative to said main mold section between an open mold position wherein said end section is spaced from said main section and a closed mold position where said end section is closer to said main section, an elongated, electroconductive ribbon extending along the space between said end section and said main section entirely below said upper shaping surface, guiding means located laterally outside each of said elongated shaping rails and having a surface engaging said ribbon to control the vertical position of said flexible electroconductive ribbon to one below said shaping surface, a pair of electrodes comprising an electrode laterally outside each of said guiding means for electrical connection with the ends of said ribbon and means carried in electrically insulated relation to said mold and its support adapted to couple said pair of electrodes with a source of electrical energy, said apparatus being free of any structural element above the area enclosed by said rigid metal shaping rails to facilitate loading and unloading of a glass sheet relative to said mold.
A method of bending a glass sheet to a sharp bend by the gravity sag technique on an outline sectionalized mold comprising supporting a flat glass sheet intermediate its end on a pair of transversely spaced ends of elongated shaping rails forming a main section of said mold and at one longitudinal end portion thereof on the longitudinally outer portion of an end shaping rail pivotally movable between a spread mold position where its inner ends are spaced from the ends of said main section shaping rails and a closed mold position wherein said ends of said shaping rails are adjacent to one another so that a main portion of said glass sheet is superimposed over said main section of the mold and an end portion of said glass sheet is superimposed over said end shaping rail of the mold, supporting an electroconductive ribbon below and in approximate alignment with a line of support provided by said pair of ends of said main section shaping rails, heating the glass sheet in an enclosed hot atmosphere to an elevated temperature, applying electric current to said electroconductive ribbon whereby the latter radiates heat upward toward the bottom surface of said supported glass sheet, pivoting said end shaping rail upward to fold the end portion of said glass sheet supported thereon relative to the main portion of said glass sheet along a line aligned with the length of said ribbon.
Dependencies are inferred from the claim text.