US 5,669,952 AGranted

Pressure forming of glass sheets

AssigneePPG Industries, Inc.

InventorsGeorge R. Claassen, Irvin A. Wilson, David B. Rayburn, John L. McLaughlin, Rudolph A. Karlo, Jeffrey L. Marietti

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Abstract

The present invention discloses a method for shaping glass sheets to deeply sagged configurations using a lower outline mold and an upper shaping mold while minimizing marking of the sheets by shaping molds. The outline mold includes a support rail which generally corresponding to the desired curvature of a peripheral portion of the sheets to be shaped and supports the glass sheets as they are heated and sagged by gravity to a preliminary shape. The outline mold and the upper mold are then moved relative to each other to position the molds either in close proximity to each other or to press the upper mold against the glass sheets. Pressurized gas is then directed from the mold to at least the unsupported central portions of the preliminarily shaped sheets, to urge these unsupported portions downward and shape the sheets to a desired configuration.

Claims49

Dependent claims

A method for shaping heat softenable sheet material, comprising:

supporting at least one sheet to be shaped on an outline mold having a sheet engaging surface generally corresponding to a desired curvature of peripheral portions of said sheet to be shaped, said sheet having an upper major surface and a lower major surface;
heating said sheet to its heat softening temperature such that said peripheral portions of said sheet along said lower major surface of said sheet sag by gravity into contact with said outline mold and generally conform to said sheet engaging surface of said outline mold and unsupported central portions of said sheet within said outline mold sag by gravity to preliminarily shape said sheet;
first moving said outline mold and an upper mold, having a sheet shaping surface which includes peripheral shaping portions that generally correspond to said desired curvature of said peripheral portion of said sheet and a central portion that has a predetermined curvature which is less than a desired curvature of said unsupported central portions of said sheet, relative to each other such that said peripheral shaping portions of said sheet shaping surface of said upper mold are spaced from but in close proximity to said peripheral portions of said sheet;
directing pressurized gas from said upper mold toward said upper major surface of said sheet at least along said unsupported central portions of said sheet to urge said unsupported central portions away from said central portion of said sheet shaping surface of said upper mold and shape said unsupported central portions of sheet to said desired curvature of said unsupported central portions which is greater than said predetermined curvature of said central portion of said sheet shaping surface of said upper mold;
and
subsequently moving said outline mold and said upper mold relative to each other such that said peripheral shaping portions of said sheet shaping surface of said upper mold are removed from being in close proximity to said peripheral portions of said sheet, wherein said sheet is contacted only by said sheet engaging surface of said outline mold during said heating, first moving, directing and subsequent moving steps.

3 more elements

A method for shaping heat softenable sheet material, comprising:

supporting at least one sheet to be shaped on an outline mold having a sheet engaging surface generally corresponding to a desired curvature of peripheral portions of said sheet;
heating said sheet to its heat softening temperature such that said peripheral portions of said sheet sag by gravity into contact with and generally conform to said sheet engaging surface of said outline mold and unsupported central portions of said sheet within said outline mold sag by gravity to preliminarily shape said sheet;
first moving said outline mold and an upper mold, having a sheet shaping surface which includes peripheral shaping portions that generally correspond to said desired curvature of said peripheral portions of said sheet and a central portion that has a predetermined curvature which is less than a desired curvature of said unsupported central portions of said sheet, relative to each other such that said peripheral portions of said sheet are pressed between said peripheral shaping portions of said sheet shaping surface of said upper mold and said sheet engaging surface of said outline mold;
directing pressurized gas from said upper mold against at least said unsupported central portions of said sheet to urge said unsupported central portions away from said central portion of said sheet shaping surface of said upper mold and shape said unsupported central portions of said sheet to said desired curvature of said unsupported central portions which is greater than said predetermined curvature of said central portion of said sheet shaping surface of said upper mold;
and
subsequently moving said outline mold and said upper mold relative to each other such that said peripheral portions of said sheet are no longer pressed between said peripheral shaping portions of said sheet shaping surface of said upper mold and said sheet engaging surface of said outline mold, wherein said sheet is contacted only by said sheet engaging surface of said outline mold and said peripheral shaping portions of said sheet shaping surface of said upper mold during said heating, first moving, directing and subsequent moving steps.

3 more elements

A method for shaping heat softenable sheet material, comprising:

supporting at least one sheet to be shaped on an outline mold having a sheet engaging surface generally corresponding to a desired curvature of peripheral portions of said sheet;
heating said sheet to its heat softening temperature such that said peripheral portions of said sheet sag by gravity into contact with and generally conform to said sheet engaging surface of said outline mold and unsupported central portions of said sheet within said outline mold sag by gravity to preliminarily shape said sheet;
first moving said outline mold and an upper shaping member, having only a peripheral shaping surface that generally corresponds to said desired curvature of said peripheral portions of said sheet, relative to each other such that said peripheral portions of said sheet are pressed between peripheral shaping surface of said upper shaping member and said sheet engaging surface of said outline mold;
directing pressurized gas from said upper shaping member toward at least said unsupported central portions of said sheet to urge said unsupported central portions away from said upper shaping member and shape said sheet to a desired configuration;
and
subsequently moving said outline mold and said upper shaping member relative to each other such that said peripheral portions of said sheet are no longer pressed between peripheral shaping surface of said upper shaping member and said sheet engaging surface of said outline mold, wherein said sheet is contacted only by said sheet engaging surface of said outline mold and said peripheral shaping surface of said upper shaping member during said heating, first moving, directing and subsequent moving steps.

3 more elements

A method for shaping glass sheets, comprising:

supporting a pair of overlaying upper and lower glass sheets on an outline mold having a sheet engaging surface generally corresponding to a desired curvature of peripheral portions of said upper and lower sheets;
heating said sheets to their heat softening temperature such that said peripheral portions of said sheets sag by gravity with peripheral portions of said lower sheet contacting and generally conforming to said sheet engaging surface of said outline mold and unsupported central portions of said sheets within said outline mold sag by gravity to preliminarily shape said sheets;
first moving said outline mold and an upper mold, having a sheet shaping surface which includes peripheral shaping portions that generally correspond to said desired curvature of said peripheral portions of said sheets and a central portion that has a predetermined curvature which is less than a desired curvature of said unsupported central portions of said sheets, relative to each other such that said peripheral shaping portions of said sheet shaping surface of said upper mold are spaced from but in close proximity to said peripheral portions of said sheets;
directing pressurized gas at a generally uniform temperature from said upper mold toward said unsupported central portions of said sheets to urge said unsupported central portions away from said central portion of said sheet shaping surface of said upper mold and shape said pair of sheets to a desired configuration, wherein said unsupported central portions are shaped to said desired curvature of said unsupported central portions which is greater than said predetermined curvature of said central portion of said sheet shaping surface of said upper mold;
and
subsequently moving said outline mold and said upper mold relative to each other such that said peripheral shaping portions of said sheet shaping surface of said upper mold are removed from being in close proximity to said peripheral portions of said sheets, wherein said sheets are contacted only by said sheet engaging surface of said outline mold during said heating, first moving, directing and subsequent moving steps.

3 more elements

A method for shaping glass sheets, comprising:

supporting a pair of overlaying upper and lower glass sheets on an outline mold having a sheet engaging surface generally corresponding to a desired curvature of peripheral portions of said upper and lower sheets;
heating said sheets to their heat softening temperature such that said peripheral portions of said sheets sag by gravity with peripheral portions of said lower sheet contacting and generally conforming to said sheet engaging surface of said outline mold and unsupported central portions of said sheets within said outline mold sag by gravity to preliminarily shape said sheets;
first moving said outline mold and an upper mold, having a sheet shaping surface which includes peripheral shaping portions that generally correspond to said desired curvature of said peripheral portions of said sheets and a central portion that has a predetermined curvature which is less than a desired curvature of said unsupported central portions of said sheets, relative to each other such that said peripheral portions of said sheets are pressed between said peripheral shaping portions of said sheet shaping surface of said upper mold and sheet engaging surface of said outline mold;
directing pressurized gas at a generally uniform temperature from said upper mold toward said unsupported central portions of said sheets to urge said unsupported central portions away from said central portion of said sheet shaping surface of said upper mold and shape said pair of sheets to a desired configuration, wherein said unsupported central portions are shaped to said desired curvature of said unsupported central portions which is greater than said predetermined curvature of said central portion of said sheet shaping surface of said upper mold;
and
subsequently moving said outline mold and said upper mold relative to each other such that said peripheral portions of said sheets are no longer pressed between said peripheral shaping portions of said sheet shaping surface of said upper mold and sheet engaging surface of said outline mold, wherein said sheets are contacted only by sheet engaging surface of said outline mold and said peripheral shaping portions of said sheet shaping surface of said upper mold during said heating, first moving, directing and subsequent moving steps.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/323,480Filed 14 Oct 1994
Granted: 23 Sep 1997
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

C03B 23/0355
By suction or blowing out for providing the deformation force to bend the glass sheet: by blowing without suction directly on the glass sheet
C03B 23/0252
By gravity: by gravity only, e.g. sagging
C03B 23/0256
By gravity: gravity bending accelerated by applying mechanical forces, e.g. inertia, weights or local forces
C03B 23/0305
By press-bending between shaping moulds: press-bending accelerated by applying mechanical forces, e.g. inertia, weights or local forces