WO2002030838A1

WO2002030838A1 - Glass sheet forming mold

Info

Publication number: WO2002030838A1
Application number: PCT/US2000/027957
Authority: WO
Inventors: Roger E. Hummel
Original assignee: Glasstech, Inc.
Priority date: 2000-10-10
Filing date: 2000-10-10
Publication date: 2002-04-18
Also published as: AU2000280058A1

Abstract

A glass sheet forming mold (20) includes a frame (32) that supports a peripheral mold ring (34) having a contoured shape (38) with a contoured surface (40) that forms a heated flat glass sheet. Inside of a design glass line (42) on the mold ring contoured surface (40), a relief portion (44) is spaced from the design shape of the formed glass sheet. Outside of the design glass line (42), the mold ring contoured surface (40) has at least one upper flat portion (48) for initially contacting a heated flat glass sheet prior to the forming.

Description

GLASS SHEET FORMING MOLD

TECHNICAL FIELD

This invention relates to a glass sheet forming mold for forming heated glass sheets to a design shape during a forming operation.

BACKGROUND ART

Glass sheets are conventionally heated within a furnace heating chamber to a sufficiently high temperature to permit forming thereof to a design shape and thereafter are cooled to provide annealing, heat strengthening or tempering. When heated, the softened glass sheet is susceptible to scratching, marring or other surface deformation including chipping upon, first contacting a forming mold onto which the glass sheet is dropped for forming.

DISCLOSURE OF INVENTION

An object of the present invention is to provide an improved glass sheet forming mold for forming heated glass sheets without surface deformation.

In carrying out the above object, the glass sheet forming mold of the invention includes a frame for mounting in a glass sheet forming system that is operable to heat and form glass sheets to a design shape. A peripheral mold ring of the mold is mounted on the frame and has an upwardly facing contoured surface for receiving a heated flat glass sheet for forming. The mold ring has a contoured surface with a design glass line that has the design shape of a glass sheet edge after forming thereof by the mold ring. The contoured surface of the mold ring inside of the design glass line has a relief portion that is spaced from the adjacent portion of the design shape of the glass sheet edge portion. Outside of the glass line, the contoured surface has at least one upper flat portion that initially contacts the heated flat glass sheet upon being received by the mold ring for the forming to the design shape.

The glass sheet forming mold of the invention has particular utility for mold rings with a unitary construction with a contoured surface fixed at the design shape as opposed to articulated molds which have portions that pivot with respect to each other.

In the preferred construction of the glass sheet forming mold, the relief portion of the contoured surface of the mold ring defines an angle in the range of 5 to 20° with the adjacent portion of the design shape of the glass sheet edge portion and, most preferably, this angle is in the range of 8 to 15°.

The glass sheet forming mold also has particular utility when it has an elongated shape including opposite ends having upper flats that respectively initially support opposite ends of an elongated heated flat glass sheet upon being received by the mold ring for the forming to the design shape.

The objects, features and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIGURE 1 is a schematic side elevational view of a glass sheet forming system that includes a forming mold constructed in accordance with the invention for forming heated flat glass sheets.

FIGURE 2 is an enlarged side elevational view taken in the same direction as Figure 1 but at an enlarged scale to further illustrate the forming mold. FIGURE 3 is a top plan view of the forming mold taken along the direction of line 3-3 in Figure 2.

FIGURE 4 is a partial top plan view that shows a peripheral mold ring of the forming mold as having a contoured surface with a phantom line indicated design glass line and an upper flat that initially receives the hot glass sheet for the forming.

FIGURE 5 is a sectional view taken through the mold ring along the direction of line 5-5 in Figure 4 and illustrates the manner in which an upper flat portion of the mold ring supports the glass sheet upon initially being received by the mold ring.

FIGURE 6 is a view similar to Figure 5 but taken after the forming to illustrate a relief portion of the mold ring contoured surface that is spaced from the adjacent glass sheet edge portion inwardly of the glass line.

FIGURES 7 and 8 are views similar to Figure 6 but illustrating different constructions of the contoured surface of the mold ring.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to Figure 1 of the drawings, a schematically illustrated glass sheet forming system 10 includes a furnace 12 in which glass sheets G are heated on a heating conveyor 14 of the roll type. This heating is performed upon conveyance along a direction of conveyance illustrated by arrow C which is toward the right as shown. The forming system 10 also includes a transfer station 16 having a topside transfer platen 18 that transfers the hot glass sheets to a lower forming mold 20 that is constructed in accordance with this invention. The topside transfer platen 18 is fixedly mounted upon suitable unshown framework and is preferably of the type shown by United States Patent 5,002,599 McMaster et al. , the entire disclosure of which is hereby incorporated by reference, so as to support a heated glass sheet from above by vacuum and pressurized air without any direct contact. The transfer platen 18 transfers the hot glass sheets G to the lower forming mold 20 whose construction is hereinafter more fully described. A forming station 22 of the system is located to the right of the transfer station 16 and includes an upper mold 24 that is movable vertically as shown by arrows 25. The forming mold 20 moves a heated glass sheet from the transfer station 16 to the forming station 22 with a heated glass sheet thereon whereupon- downward movement of the upper mold 24 provides press forming of the heated glass sheet between the molds. A cooling station 26 of system 10 includes lower and upper quench heads 28 and 30 for providing cooling gas that cools the formed glass sheet after movement thereof between the quench heads on the forming mold 20 or otherwise in any suitable manner.

With reference to Figures 2 and 3, the glass sheet forming mold 20 of this invention includes a frame 32 that is mounted in a suitable manner within the glass sheet forming system to provide the horizontal movement previously described between the transfer station and the forming station. A peripheral mold ring 34 of the forming mold 20 is mounted on the frame 32 by mounts 36 that can be adjusted by shims to provide the proper positioning with respect to the frame. The mold ring 34 has an upwardly facing contoured shape 38 for receiving the heated flat glass sheet G for forming as best shown in Figure 2. As shown in Figures 4 and 6, a contoured surface 40 of the mold ring 34 has a design glass line 42 that has the design shape of a glass sheet edge after forming thereof by the mold ring as illustrated specifically in Figure 6. The contoured surface 40 of the mold ring 34 inside of the design glass line 42 has a relief portion 44 that is spaced from the adjacent portion of the glass sheet edge portion 46. Outside of the glass line 42, the contoured surface 40 has at least one upper flat 48 that initially contacts and supports the heated flat glass sheet G as shown in Figure 5 upon being received by the mold ring for the forming to the design shape. After such forming, the curvature of the glass sheet moves its edge portion 46 inwardly so as to terminate at the glass line 42 shown in Figure 6.

The construction of the glass sheet forming mold 20 and its mold ring

34 as described above permits forming of glass sheets without edge portion deformation. This forming mold has particular utility when the mold ring 34 has a unitary construction with its contoured surface 40 fixed at the design shape as opposed to articulated molds where mold portions pivot with respect to each other.

As shown in Figure 6, the relief portion 44 of the contoured surface 40 of the mold ring 34 defines an angle α in the range of 5 to 20° with the adjacent edge portion 46 of the design shape of the glass sheet edge portion 48. This angle α most preferably is in the range of 8 to 15°.

As best illustrated in Figures 2 and 3, the mold ring 34 of the forming mold 20 has an elongated shape including opposite ends 50 that have the upper flats 48 for respectively initially supporting opposite ends of an elongated heated flat glass sheet upon being received by the mold ring for the forming to the design shape. While the elongated direction of the forming mold 20 has been shown extending along the direction of conveyance C for ease of illustration, most elongated molds will have their elongated directions extending transversely to the direction of conveyance in actual production jobs .

Different constructions of the contoured surface are possible as disclosed by Figures 6, 7 and 8. In the construction of Figure 6, the contoured surface 40 extends downwardly from the upper flat 48 with the designed shape of the formed glass sheet edge portion 46 but is rotated about the glass line 42 in a counterclockwise direction by the angle α defined with the relief portion 44. Thus, outside of the glass line 42, the contoured surface is above and inward of an extension of the lower surface of the formed glass sheet edge portion 46.

In the mold construction of Figure 7, the contoured surface 40 outside of the glass line 42 is a continuation of the design shape of the lower surface of the adjacent glass sheet edge portion 46 and the relief portion 44 is relieved from that design shape by the angle a as previously described.

In the construction of Figure 8, the contoured surface 40 outside of the glass line 42 is a continuation of the design shape of the lower surface of the adjacent glass sheet edge portion 46. Furthermore, the contoured surface 40 extends inwardly from the glass line 42 about three or four millimeters with the design shape of the lower surface of the glass sheet edge portion 46 and inside thereof the relief portion 44 defines the angle . This construction works best with glass sheets where the edge portion is partially covered to hide any distortion that results from the support provided for the glass sheet edge portion 46 inside of the glass line 42.

Also, while the forming mold 20 has rounded opposite ends 50 as shown, the mold may have a more rectangular shape with four corners.

Furthermore, depending upon the mold contour, it is possible for only two of the four corners to have the flats that initially contact the glass sheet during the forming.

In other cases, all four of the mold corners will have the flats.

While the best mode for practicing the invention has been described in detail, those familiar with the art Jo which this invention relates will recognize various alternative embodiments for practicing the invention as defined by the following claims.

Claims

WHAT IS CLAIMED IS:

1. A glass sheet forming mold comprising: a frame for mounting in a glass sheet forming system that is operable to heat and form glass sheets to a design shape; a peripheral mold ring that is mounted on the frame and has an upwardly facing contoured shape for receiving a heated flat glass sheet for forming; the mold ring having a contoured surface with a design glass line that has the design shape of a glass sheet edge after forming thereof by the mold ring; the contoured surface of the mold ring inside of the design glass line having a relief portion that is spaced from the adjacent portion of the design shape of the glass sheet edge portion; and the contoured surface outside of the glass line having at least one upper flat portion that initially contacts the heated flat glass sheet upon being received by the mold ring for the forming to the design shape.

2. A glass sheet forming mold as in claim 1 wherein the mold ring has a unitary construction with its contoured surface fixed at the design shape.

3. A glass sheet forming mold as in claim 1 wherein the relief portion of the contoured surface of the mold ring defines an angle in the range of 5 to 20° with the adjacent portion of the design shape of the glass sheet edge portion.

4. A glass sheet forming mold as in claim 1 wherein the relief portion of the contoured surface of the mold ring defines an angle in the range of 8 to 15° with the adjacent portion of the design shape of the glass sheet edge portion.

5. A glass sheet forming mold as in claim 1 wherein the mold ring has an elongated shape including opposite ends having upper flats . that respectively initially support opposite ends of an elongated heated flat glass sheet upon being received by the mold ring for the forming to the design shape.