US 6,629,436 B1 · Apparatus for thermal treatment of glass and method and thermally treated glass therefrom

Abstract

The present invention is directed to an apparatus for thermal treatment of glass and method and thermally treated glass therefrom. The apparatus is capable of supporting the glass during thermal treatment such as tempering, annealing, bending, and/or shaping which can include any cooling or quenching to remove heat or any combination of these. The apparatus is a support member like a ring or outline mold with a horizontal surface suitable for contacting the glass. The support member has at least a surface with or without a coating for contact with the glass of one or more metals having a thermal conductivity such that the glass heated for shaping cools at a rate not much slower than the cooling rate of unsupported sections of the glass. Suitable metals include those with a thermal conductivity of greater than around 16 BTU/(hour×feet×° F.). When a coating covers at least a portion of the support, the coating can give the support member more heat resistance and/or anti-corrosiveness and/or abrasion resistance to improve durability. Also the support member can be the shaping rail of a windshield or backlite shaping iron.

Claims20

Dependent claims

A glass shaping apparatus, comprising:

a support frame;
an outline shaping rail supported on said frame, the shaping rail having a sheet shaping surface that conforms in elevation and outline to a final desired shape of a marginal edge of a glass sheet to be shaped and having an open area within the outline shaping rail wherein the open area within the shaping rail is void of a sheet-supporting member, the shaping rail providing support around a substantial portion of the perimeter of the glass sheet to be shaped wherein the sheet shaping surface is comprised of material selected from the group of:
i) metals having a thermal conductivity of greater than 16 BTU/(hr. ft. ° F.), or ii) low thermal mass materials with a melting point higher than 1100° F., where low thermal mass means the thermal mass, weight or volume of the material of the rail multiplied by that materials specific heat or thermal capacity or heat capacity so as not to act as a heat sink for the heated glass sheet to be shaped.

A method of shaping a glass sheet by gravity sag bending, including the steps of;

providing a shaping rail with a shaping surface of a elongated transverse portion having an elevational contour and outline generally corresponding to a final desired shape of a marginal edge portion of a sheet to be shaped and where such surface is comprised of material selected from the group of:
i) metals having a thermal conductivity of greater than 16 BTU/(hr. ft. ° F.), or ii) low thermal mass materials with a melting point higher than 1100° C., where low thermal mass means the thermal mass, weight or volume of the material of the rail multiplied by that materials specific heat or thermal capacity or heat capacity so as not to act as a heat sink for the heated glass sheet to be shaped;
supporting an auxiliary rail having an upper shaping surface generally corresponding to a preliminary shape of a selected marginal edge portion of said sheet, in a first position along an adjacent section of said shaping rail, wherein said upper shaping surface of said auxiliary rail is above at least a portion of said shaping surface of said adjacent shaping rail section;
placing said sheet on said shaping rail and said auxiliary rail such that said selected marginal edge portion of said sheet is supported by said upper shaping surface of said auxiliary rail and above said portion of said shaping surface of said adjacent shaping rail section;
heating said sheet to its heat softening temperature such that a first portion of said sheet sags by gravity into contact with portions of said upper shaping surface of said shaping rail and said selected marginal edge portion of said sheet contacts said upper shaping surface of said auxiliary rail, to preliminarily shape said sheet;
and
lowering said auxiliary rail to deposit said selected marginal edge portion of said sheet onto said adjacent shaping rail section so as to allow said selected marginal edge portion of said sheet to sag into contact with said portion of said upper shaping surface of said adjacent shaping rail section and allow said sheet to sag to said final desired configuration.

4 more elements

Dependencies are inferred from the claim text.

Apparatus for thermal treatment of glass and method and thermally treated glass therefrom

Life of this patent

Apparatus for thermal treatment of glass and method and thermally treated glass therefrom

Life of this patent

Abstract

Claims20