GLASS SHAPING APPARATUS

Abstract

The invention relates to a method for shaping a glass sheet having a reflective low emissivity coating thereon comprising the steps: (i) positioning the coated glass sheet at a furnace entrance; (ii) conveying the coated glass sheet through the furnace to heat the glass sheet to a temperature suitable for shaping; (iii) transferring the coated glass sheet on to a first bending tool for supporting the coated glass sheet, the first bending tool having a fixed wall and first, second and third movable walls; (iv) moving at least one of the first, second and third movable walls to adjust the position of the coated glass sheet on the first bending tool ring from a first position to a second position; and (v) shaping the coated glass sheet between the first bending tool and a die. Apparatus for carrying out the method is also disclosed.

Claims

1. A method for shaping a glass sheet having a reflective low emissivity coating thereon comprising: (i) positioning the coated glass sheet at a furnace entrance; (ii) conveying the coated glass sheet through the furnace to heat the coated glass sheet to a temperature suitable for shaping; (iii) transferring the coated glass sheet on to a first bending tool for supporting the coated glass sheet, the first bending tool having a fixed wall and first, second and third movable walls; (iv) moving at least one of the first, second and third movable walls to adjust the position of the coated glass sheet on the first bending tool ring from a first position to a second position; and (v) shaping the coated glass sheet between the first bending tool and a die.

2. A method according to claim 1, wherein during step (iv) the first, second and third movable walls are moved to adjust the position of the coated glass sheet on the first bending tool.

3. A method according to claim 1, wherein the first bending tool is a shaping ring.

4. A method according to claim 1, including monitoring a position of the coated glass sheet on the first bending tool to provide an output, wherein the output is used to provide an input for moving the coated glass sheet, or a subsequent coated glass sheet, from the first position to the second position.

5. Apparatus for shaping a coated glass sheet comprising a roller conveyor for conveying a coated glass sheet, a die and frame having a rim for supporting the coated glass sheet thereon in the shape of a target product, the frame having a fixed wall and at least one movable wall.

6. Apparatus according to claim 5, comprising at least two movable walls.

7. Apparatus according to claim 5, comprising at least three movable walls.

8. Apparatus according to claim 5, wherein the at least one movable wall is movable in a horizontal direction.

9. Apparatus according to claim 8 wherein the movable wall is moveable by an oscillating movement.

10. Apparatus according to claim 5, further comprising a camera for monitoring the shaping operation, the camera being combined with a control system for controlling the movement of at least one of the movable walls.

Description

[0024] The present invention will now be described with reference to the following FIGURE (not to scale) in which:

[0025] FIG. 1 is a plan view of a portion of a coated glass shaping line.

[0026] A press bending station for bending a coated glass sheet according to the invention has a roller conveyor for the coated glass sheet, a die and frame with a rim characterized in that the frame is in the shape of the target product and consists of a fixed wall/support and three movable walls that may move horizontally in an oscillating movement. Preferably the press bending station includes a camera for observing the pressing action, combined with a control system for moving the movable walls of the frame.

[0027] In a preferred embodiment the method is based on the use of a frame consisting of four seperable walls including three movable walls that allows an adjustment of the position of the coated glass sheet before bending by moving the sides of the frame. When the coated glass sheet rotates or moves in a heating oven, the frame is able to correct the position coated glass sheet. The frame then is used as the lower support for the coated glass sheet which is pressed between a die and the frame to provide the desired shape.

[0028] FIG. 1 shows a schematic plan view of a press bending station of the type just described. The press for bending glass comprises a frame 1 for supporting the coated glass sheet 20 thereon, and a die (not shown) to press the coated glass sheet supported on the frame 1. A roller conveyor having rollers (one of which is shown and labelled 8) transports the coated glass sheet 20 in a direction of glass travel shown by arrow 12.

[0029] The frame 1 is in the shape of the target product and has a fixed retaining wall 2, and three movable walls 3, 4 and 5 that are movable horizontally in the direction of respective arrows 3′, 4′ and 5′. The movable walls 3, 4 and 5 provide the frame 1 with a movable surface or rim. A camera 6 is used to monitor the pressing operation and is in communication with control system 7 via suitable cabling 9. The control system 7 is in communication (via suitable cabling 10) with the movable walls 3, 4 and 5 of the frame 1 to allow control of the movement thereof.

[0030] The coated glass sheet 20 has a reflective low emissivity coating on a major surface thereof facing away from the conveyor rollers. The coated glass sheet 20 is accurately positioned before entering a heating furnace. After heating the coated glass sheet can rotate on the conveyor rollers 8. The rotated coated glass sheet is deposited on the frame 1 and is prevented from moving in the direction of glass travel 12 by the fixed retaining wall 2. The movable walls 3, 4 and 5 are sufficiently opened to allow the coated glass sheet to be supported thereon. The movable walls are then moved to the correct position using a predetermined algorithm by moving the movable walls with respect to the fixed wall 2 to correct the position of the coated glass sheet 20. With the coated glass sheet in the corrected position for bending, the coated glass sheet is shaped using an upper die (not shown). The corrected position of the coated glass sheet on the frame 1 avoids abnormal/incorrect shaping of the coated glass sheet.

[0031] In addition, the camera 6 is oriented to monitor the pressing operation and can verify the accuracy of the positioning of the coated glass sheet by the frame 1. An operator is able observe images from the camera to make on-the-fly adjustments to the positioning of the coated glass sheet by the movable wall of the frame.

[0032] The present invention provides an apparatus and method for shaping coated glass sheets that allows movement of a coated glass sheet during a heating step in a heating furnace to be corrected such that after the coated glass sheet has been heated, the coated glass sheet can be moved into a desired position for bending.