Glass sheet forming method and apparatus utilizing lower full surface vacuum mold and upper ring mold

Apparatus for forming a flat glass sheet, comprising:

• a heating conveyor for heating the flat glass sheet to a sufficiently high temperature to permit forming thereof;
• an upper topside transfer device having a downwardly facing flat surface for receiving the heated flat glass sheet from the heating conveyor;
• a lower vacuum mold having an upwardly facing full surface with at least a portion thereof having an upwardly convex shape for receiving the heated flat glass sheet from the downwardly facing flat surface of the upper topside transfer device, and the lower vacuum mold having openings through which a vacuum is drawn at the full surface thereof to provide forming of the glass sheet;
• an upper ring mold including an enclosure for defining a vacuum chamber;
• an actuator for moving the upper ring mold downwardly to form and seal the periphery of the glass sheet against the surface of the lower vacuum mold at which a vacuum is drawn within the sealed periphery of the glass sheet to form the entire extent of the glass sheet to the shape of the lower vacuum mold surface, a vacuum then being provided within the vacuum chamber of the upper ring mold to support the formed glass sheet on the ring mold, and the actuator thereafter moving the upper ring mold and the formed glass sheet upwardly to a vertical elevation above the lower vacuum mold;
• and
• a cooling mold for receiving the formed glass sheet from the upper ring mold for cooling.

Apparatus for forming a flat glass sheet, comprising:

• a heating conveyor for heating the flat glass sheet to a sufficiently high temperature to permit forming thereof, and the heating conveyor being selected from the group consisting of:
• a. a gas hearth conveyor that supports the flat glass sheet on a thin film of gas during the heating, and
• b. a roller conveyor including rollers that rotate to transport and convey the flat glass sheet during the heating;
• an upper topside transfer device having downwardly facing flat surface for receiving the heated flat glass sheet from the heating conveyor, and the topside transfer device being selected from the group consisting of:
• a. a gas suspension platen for supporting the heated flat glass sheet received from the conveyor without direct engagement therewith, and
• b. a vacuum platen for supporting the heated flat glass sheet received from the conveyor in direct engagement therewith;
• a lower vacuum mold having an upwardly facing full surface with at least a portion thereof having an upwardly convex shape for receiving the heated flat glass sheet from the downwardly facing flat surface of the upper topside transfer device, and the lower vacuum mold having openings through which a vacuum is drawn at the full surface thereof to provide forming of the glass sheet;
• an upper ring mold including an enclosure for defining a vacuum chamber and also including a shape retention pad;
• an actuator for moving the upper ring mold downwardly to form and seal the periphery of the glass sheet against the surface of the lower vacuum mold at which a vacuum is drawn within the sealed periphery of the glass sheet to form the entire extent of the glass sheet to the shape of the lower vacuum mold surface, a vacuum then being provided within the vacuum chamber of the upper ring mold to support the formed glass sheet on the ring mold and the shape retention pad preventing undesired forming of the glass sheet by the vacuum drawn within the vacuum chamber of the ring mold, and the actuator thereafter moving the upper ring mold and the formed glass sheet upwardly to a vertical elevation above the lower vacuum mold;
• and
• a cooling mold for receiving the formed glass sheet from the upper ring mold for cooling.

A method for forming a flat glass sheet, comprising:

• heating the flat glass sheet to a sufficiently high temperature for forming;
• transferring the heated flat glass sheet to a downwardly facing surface of a topside transfer device;
• releasing the heated flat glass sheet from the topside transfer device onto a full surface of a lower vacuum mold having at least a portion with an upwardly convex shape;
• thereafter pressing the glass sheet between the lower vacuum mold and an upper ring mold to form and seal the periphery of the glass sheet against the lower vacuum mold surface;
• drawing a vacuum at the vacuum mold surface within the sealed periphery of the glass sheet to form the entire extent of the glass sheet to the shape of the vacuum mold surface;
• and
• finally drawing a vacuum within an enclosure of the upper ring mold such that the upper ring mold receives and delivers the formed glass sheet from the vacuum mold for cooling.