Three stage forming station and method for forming a hot glass sheet with transverse curvature

Patent metadata

Field	Value
Publication number	US-9452948-B2
Application number	US-201414174265-A
Country	US
Kind code	B2
Filing date	Feb 6, 2014
Priority date	Feb 6, 2014
Publication date	Sep 27, 2016
Grant date	Sep 27, 2016

Abstract

A glass sheet three stage forming station utilizes first and second upper molds and a lower mold to provide three stage forming. The glass is curved on the upper mold in the first stage but retains straight line elements transverse to the curvature. Transfer of the initially formed glass sheet from the first upper mold to the lower mold then provides the second stage of gravity forming and the glass sheet is then press formed between the second upper mold and the lower mold in the third stage which reduces optical distortion in the central viewing area of the formed glass sheet. The glass sheet is moved horizontally on the first upper mold and released onto the lower mold.

First claim

What is claimed is:

1. A three stage forming station for forming a hot glass sheet with transverse curvature comprising:
a housing having a heated chamber;
a roll conveyor for conveying the hot glass sheet into the heated chamber of the housing along a horizontal plane of conveyance;
a downwardly facing first upper mold, that has a pickup position above the roll conveyor in the heated chamber and that has curvature in a first direction and straight line elements in a second direction transverse to the first direction, for initially forming the glass sheet with curvature in the first direction while maintaining straight line elements in the second direction;
an upwardly facing lower mold, that is located in the heated chamber spaced horizontally from the pickup position of the first upper mold and that has curvature in the first direction and permits glass sheet curvature in the second direction, for receiving the glass sheet from the first upper mold in a delivery position thereof above the lower mold so the glass sheet sags under gravity along the second direction to have some curvature in the second direction as well as curvature in the first direction;
a downwardly facing second upper mold, that is located in the heated chamber above the lower mold and has transverse curvature and is complementary to the upwardly facing lower mold, for cooperating with the lower mold to press form the glass sheet with transverse curvature corresponding to the shapes of the lower mold and the second upper mold;
elongated beams that support the first upper mold;
rollers that support the elongated beams and the first upper mold thereon for horizontal movement within the heated chamber;
a horizontal actuator that moves the elongated beams horizontally on the rollers to move the first upper mold horizontally between the pickup position above the roll conveyor and the delivery position above the lower mold;
a gas lift jet array located below the plane of conveyance to supply upwardly directed lift jets for lifting the glass sheet upwardly from the roll conveyor to the first upper mold when located in its pickup position to initially form and support the glass sheet on the first upper mold;
vertical actuators that move the rollers, the elongated beams on the rollers, and the first upper mold vertically in the pickup position first downwardly toward the roll conveyor to facilitate the lifting of the glass sheet from the conveyor to the first upper mold and then upwardly to facilitate movement of the first upper mold on the elongated beams to the delivery position;
a vacuum source for drawing a vacuum at the first upper mold to support the initially formed glass sheet on the first upper mold for its movement from the pickup position to the delivery position where its vacuum is terminated to release the glass sheet onto the lower mold;
the second upper mold being movable downwardly from an upper position to cooperate with the lower mold to press form the glass sheet with curvature in transverse directions, and the second upper mold being subsequently movable upwardly to the upper position with the press formed glass sheet supported on the second upper mold by vacuum drawn by the vacuum source;
a delivery mold that is movable to below the press formed glass sheet on the second upper mold in its upper position whereupon its vacuum is terminated and the glass sheet is released from the second upper mold onto the delivery mold which is then moved out of the forming station for delivery of the press formed glass sheet; and
a controller that operates the roll conveyor, the first upper mold, the gas lift jet array, the second upper mold, the vacuum source, and the delivery mold to perform the press forming of the glass sheet and its delivery.

2. A three stage forming station as in claim 1 wherein the controller is configured to operate the vacuum source to provide a vacuum to the first upper mold and thereby cooperate with the gas lift jet array in lifting the glass sheet from the roll conveyor into contact with the first upper mold for initial forming and support of the glass sheet.

3. A three stage forming station as in claim 2 wherein the controller is configured so after the glass sheet is moved upwardly and contacts the first upper mold, it terminates the operation of the gas lift jet array while continuing to operate the vacuum source to provide the vacuum that is then the sole support of the glass sheet on the first upper mold.

4. A three stage forming station as in claim 1 wherein lower mold has a ring shape that supports the glass sheet as it sags by gravity.

5. A three stage forming station as in claim 4 wherein the lower mold includes a support pad within its ring shape to control sagging of the glass sheet.

6. A three stage forming station as in claim 1 further including lateral rollers that contact the elongated beams to provide lateral positioning during movement of the first upper mold between its pickup position and its delivery position.

7. A three stage forming station as in claim 1 further including screw jacks for moving the lower mold vertically.

8. A three stage forming station as in claim 1 further including a quench station to which the delivery mold moves the press formed glass sheet for quenching.

9. A three stage forming station for forming a hot glass sheet with transverse curvature comprising:
a housing having a heated chamber;
a roll conveyor for conveying the hot glass sheet into the heated chamber of the housing along a horizontal plane of conveyance;
a downwardly facing first upper mold, that has a pickup position above the roll conveyor in the heated chamber and that has curvature in a first direction and straight line elements in a second direction transverse to the first direction, for initially forming the glass sheet with curvature in the first direction while maintaining straight line elements in the second direction;
an upwardly facing lower mold of a ring shape, that is located in the heated chamber spaced horizontally from the pickup position of the first upper mold and that has curvature in the first direction and permits glass sheet curvature in the second direction, for receiving the glass sheet from the first upper mold in a delivery position thereof above the lower mold so the glass sheet sags under gravity along the second direction to have some curvature in the second direction as well as curvature in the first direction, and the lower mold having a support pad within its ring shape to control sagging of the glass sheet;
a downwardly facing second upper mold, that is located in the heated chamber above the lower mold and has transverse curvature and is complementary to the upwardly facing lower mold, for cooperating with the lower mold to press form the glass sheet with transverse curvature corresponding to the shapes of the lower mold and the second upper mold;
elongated beams that support the first upper mold;
rollers that support the elongated beams and the first upper mold thereon for horizontal movement within the heated chamber;
a horizontal actuator that moves the elongated beams horizontally on the rollers to move the first upper mold horizontally between the pickup position above the roll conveyor and the delivery position above the lower mold;
a gas lift jet array located below the plane of conveyance to supply upwardly directed lift jets for lifting the glass sheet upwardly from the roll conveyor to the first upper mold when located in its pickup position to initially form and support the glass sheet on the first upper mold;
vertical actuators that move the rollers, the elongated beams on the rollers, and the first upper mold vertically in the pickup position first downwardly toward the r

Assignees

• Glasstech Inc

Inventors

• Nitschke Dean M
• Grzeszczak Jeffrey A
• Jinka Ashoka G
• Schnabel Jr James P
• Nitschke David B

Classifications

• C03B23/0355

  by blowing without suction directly on the glass sheet · CPC title

• C03B23/025 Primary

  by gravity · CPC title

• C03B23/0357

  by suction without blowing, e.g. with vacuum or by venturi effect · CPC title

• C03B35/147

  of the non-contact type · CPC title

• C03B23/0252 Primary

  by gravity only, e.g. sagging (C03B23/035 takes precedence) · CPC title