JP2008531452A - Method and apparatus for producing glass sheet - Google Patents

Abstract

  In forming the sheet glass by the overflow downdraw method, the edge portion of the sheet is allowed to flow downward on the web-like member, and then downward on the extension member that intersects the web-like member and is inclined downward with respect to the web-like member. The width of the usable sheet glass is maximized by reducing the thickness of the edge of the glass stream and maintaining the sheet width. The extension member is preferably removably attached to the web-like member and greatly facilitates easier replacement of the damaged extension member.

Description

  The present invention relates to a glass forming apparatus, and more particularly to a glass sheet forming apparatus.

  A method for producing a glass sheet by flowing molten glass downward on a forming wedge is well known. In practice, however, the width of the usable sheet produced can be substantially narrower than the maximum usable sheet width to be theoretically determined, which is determined by the longitudinal length of the forming wedge. It turns out. That is, when the molten glass flows along the lower part of the negatively inclined surface, such as the surface converging downward of the forming wedge, the width of the glass stream shrinks and the inner ends of the wedges from the vertical ends. It has been found to retract.

  This lateral movement of the molten glass creates a bead along the vertical edge of the sheet, i.e., the thickened portion, the edge bead.

  The thickened portion at the edge of the sheet not only reduces the uniform portion of usable thickness that results from the predetermined width of the stretched sheet, but also limits the stretchable speed of the sheet. That is, the sheet is annealed as a continuous process immediately after molding, and the time required for the glass sheet to reach an acceptable strain level when passing through the treated portion of the annealing process is directly proportional to the glass thickness. Therefore, the maximum sheet forming speed is limited.

  In the past, it has been proposed to prevent the glass sheet formed by the downdraw method from being narrowed by cooling with a plurality of rollers or edges.

  However, passing the roller does not attempt to correct the cause or source of the bead, it merely attempts to reduce the thickness of the beaded area and cooling has been previously pointed out. In addition, it tends to enlarge the formation of beaded edges that adversely affect the forming of the glass, which is not completely satisfactory. Furthermore, when the viscosity in the vicinity of the edge of the sheet flow is high, the degree of glass retraction, that is, narrowing, is actually more prominent than when the viscosity is low. Also, if the edge is cooled sufficiently to complete the glass, further adverse effects occur in the form of warping of the glass sheet and undesirable stress.

  A conventionally employed method for expanding the sheet width is to provide a web surface portion between the surface converging downward of the forming wedge-shaped body and the protruding edge surface portion, and this web surface portion is stretched. Helped increase the width of the glass sheet. Patent Document 1 discloses such a web surface portion, and this web surface portion terminates at a lower portion in a horizontal plane passing through a root forming an encounter line of both surface portions converging downward of a forming wedge-shaped body. ing. Patent Document 2 discloses a molding apparatus having a web surface portion, and the lowermost end of the web surface portion extends downward from the base.

  In the conventional apparatus shown in FIG. 1, an overflow trough 10 having both converging molding surface portions is provided with a plurality of edge guide bodies 12. Each edge guide 12 converges with two main parts, namely a protruding surface part 14 that intersects the forming surface part of the trough along its vertical extent, and the protruding surface part 14. And a web surface portion 16 extending between one of the molding surface portions inclined downward. However, the web surface portion 16 does not extend below the lower tip formed by the convergent molding surface portions, that is, the base.

In another conventional apparatus shown in FIG. 2, the web surface 20 extends below the lower tip or root 18, as indicated by point 22. However, whether the web surface 20 has a flat, curved, or frustoconical shape, the extended web surface can cause the glass to crack downward or kink. (That is, it indicates a sudden change in direction).
U.S. Pat. No. 3,451,798 US Pat. No. 3,537,834

  Although the above-mentioned conventional apparatus has been useful for expanding the width of the glass sheet drawn from the overflow trough, an apparatus capable of further improving the sheet width is required. Unfortunately, there is a limit to the length of the forming wedge that does not actually cause the sag problem. Therefore, it is necessary to further increase the width of the glass sheet drawn from the forming wedge without increasing the length of the forming wedge itself.

  The present invention provides a forming wedge-shaped body having an edge guide body having a web surface portion and an extended surface portion intersecting with the web surface portion, thereby forming a glass sheet by the overflow downdraw method. It is intended to actually prevent the sheet width reduction and bead formation problems encountered in the past.

  Each edge guide body includes a protruding surface portion extending along both edges of the forming surface of the wedge-shaped body, a downwardly inclined forming surface portion adjacent to the protruding surface portion, and the protruding surface portion. And a web surface portion extending therebetween.

  The web surface portion and the extended surface portion of each edge guide have a wetting length in the horizontal direction that is longer than the horizontal length of the wedge-shaped surface having a negative angle blocked by the edge guide. Before leaving the edge of the extended surface, the glass flow is widened and the thickness near its ends is reduced to prevent the formation of beads.

  In one embodiment of the present invention, an apparatus is disclosed for extending downward a glass sheet that includes a pair of forming wedges having a forming surface portion inclined downward. The pair of downwardly inclined molding surface portions converge at the bottom of the molding wedge to form a root, and define a glass drawing line along the root. The web surface portion for reducing the thickness by capturing the glass flow along the edge of the molding surface intersects the molding surface portion. The perpendicular to the web surface is horizontal everywhere. The extended surface portion intersects the web surface portion and extends downward from the web surface portion, and an outwardly directed perpendicular line located substantially at the center of the extended surface portion has a downwardly directed component. The first extended surface portion preferably cooperates detachably with respect to the first web surface portion. The first extension surface portion is preferably attached to the first web surface portion via, for example, one or more dovetail joints, whereby the first extension surface portion is separated from the first web surface portion. Easy to remove. Alternatively, a pin having a size that fits into a corresponding receiving hole in the first web surface portion may be embedded in the first extended surface portion.

  The normal of the extended surface portion preferably forms an angle β of more than about 15 ° and less than about 30 ° with respect to the normal of the web surface portion in the web surface and a vertical plane passing through the extended surface portion.

  The inner edge of the extended surface portion preferably overlaps with a vertical plane including the root.

  In another embodiment, an apparatus is provided for stretching a glass sheet having a forming wedge having a pair of downwardly inclined forming surface portions, the pair of downwardly inclined forming surface portions. Converges at the bottom of the forming wedge to form a root and defines a glass draw line along the root. The edge guide extends along the vertical edge of the molding surface, and the edge guide for reducing the thickness by capturing the glass flow along the edge of the molding surface is a web that intersects the molding surface. With a surface portion, the normal to this web surface portion is horizontal everywhere on the web surface portion. The extended surface portion intersects the web surface portion and extends downward from the web surface portion. The outwardly directed perpendicular located approximately in the center relative to the extended surface portion has a downwardly directed component.

  The first extended surface portion preferably cooperates removably with the first web surface portion. This first extended surface portion can be attached to the web surface portion via, for example, one or more dovetail joints. Alternatively, a pin having a size that fits into a receiving hole in the web surface portion may be embedded in the extended surface portion.

  The normal to the web surface and the normal to the extension surface preferably form an angle β between 15 ° and 30 ° in a vertical plane passing through both the web surface and the extension surface.

  In yet another embodiment of the present invention, a method for making a glass sheet is provided, the method comprising extending a glass sheet downwardly from a forming wedge having a pair of downwardly inclined forming surface portions, The molding surface portion inclined downwardly converges at the bottom of the molding wedge, and a glass sheet flows on the web surface portion connected to the molding surface portion, and the perpendicular to the web surface portion is horizontal everywhere. And flowing the glass sheet over an extended surface portion intersecting the web surface portion, the extended surface portion having an outwardly directed perpendicular with a downwardly directed component.

  The invention will be more readily understood and other objects, features, details and advantages will become more apparent in the course of the following illustrative description, which is not meant to imply any limitation, with reference to the accompanying drawings. I will. The features and advantages of such additional systems, methods contained herein are within the scope of the invention and are protected by the accompanying claims.

  In the following detailed description, which is intended to be illustrative and not limiting, the embodiments disclosing specific details are set forth to provide a thorough understanding of the present invention. It is. However, it will be apparent to one skilled in the art having the benefit of this specification that the present invention may be practiced in other embodiments that depart from the details disclosed herein. Furthermore, descriptions of well-known devices, methods, and materials are omitted so as not to obscure the description of the present invention. Further, similar elements are given the same reference numerals as much as possible.

  One embodiment of a glass sheet overflow down-draw apparatus according to the present invention is shown in FIG. As shown in FIG. 3, the overflow trough of the forming wedge 10 has grooves 32 that open upward and are surrounded by walls 34 on both sides in the longitudinal direction. , And terminates in an overflow weir 36 that extends in the longitudinal direction in opposition. These weirs 36 are connected to the opposing sheet-forming surfaces of the wedge-shaped body 10. As shown, the wedge 10 has a pair of generally vertical forming surface portions 38 connected to the weir 36 and a pair of lower ends terminating at a generally horizontal lower point or root 18 that forms a straight glass draw line. And a surface portion 40 that is inclined and converges.

  The molten glass 44 is supplied into the groove 32 through a delivery passage 46 communicating with the groove 32. Supply of the molten glass 44 into the groove 32 may be from one end or, if necessary, from both ends as shown in FIG. A pair of restricting dams 48 are provided above the overflow weir 36 in contact with each end of the groove 32 to guide the overflow of the free surface of the molten glass 44 over the overflow weir 36 as a separate flow, and for opposing molding. The surface portions 38 and 40 are caused to flow down to the root 18 where two separate flows converge to form a glass 52 with a virgin surface, as indicated by the dashed line.

  As shown in FIGS. 3 and 4, and according to one embodiment of the present invention, on each side of each longitudinal end of the glass forming wedge 10, there is a respective longitudinal direction of the wedge. A pair of edge guides or edge modifiers 54 are provided that extend along the vertical edge 56 of the end. Accordingly, each glass forming wedge is provided with four edge guides 54, one for each vertical corner, and as a result, the longitudinal direction of the forming wedge so that the two edge guides face each other. It is arranged at each end. The edge guide body 54 includes a projecting surface 58 that intersects the longitudinal end of the molding surface 38 along the vertical extension of the wedge-shaped body, and a surface that is inclined downward and converges with the projecting surface 58. 40, three main portions including a web surface portion 60 that extends in contact with (intersects with) 40 and an extended surface portion 62 that extends downward from the web surface portion 60.

  The web surface portion 60 intersects the protruding surface portion 58 along the intersecting line 64 and intersects the inclined surface surface portion 40 along the intersecting line 66. The intersecting lines 64 and 66 of the web surface portion 60 with respect to the protruding surface portion 58 and the inclined surface portion 40 converge at the point 68 where the top portion of the surface portion 40 inclined and converged intersects the protruding surface portion 58. It extends from. The intersection line 66 extends diagonally downward from the point 68 to a point 70 spaced inward along the wedge root 18 from the ridge surface 58. Similarly, the intersection line 64 extends downward from the point 68 to a point 72 on the ridge surface portion 58. Point 72 is preferably in a horizontal plane through root 18. However, in some embodiments, the point 72 may be above or below the horizontal plane. The lower edge of the web surface 60 is on a line 74 that extends from point 70 to point 72. As shown in FIG. 3 and described herein, the normal to the web surface 60 is preferably horizontal everywhere on the web surface 60. That is, the perpendicular 76 has no vertical component and the web surface portion 60 is vertical everywhere. The web surface portion 60 looks flat in FIG. 3 because of the drawing, but may be curved, flat, or a combination thereof. In the preferred embodiment, the web surface portion 60 is substantially planar.

  As described above, according to the present embodiment, the wedge-shaped body 10 includes a plurality of edge guide bodies, and specifically, the two edge guide bodies face each end in the longitudinal direction of the forming wedge-shaped body. The pair of edge guides 54 are provided on each side of the forming wedge-shaped body in such a manner that each edge guide body is provided at each vertical corner of the wedge-shaped body. If each web surface is substantially planar, and as shown in FIG. 5, the virtual plane parallel to the first web surface located at one end of the forming wedge is the first web surface. Against the imaginary plane parallel to the second web surface that is opposite the molding wedge, i.e., both web surfaces are opposite each other at the same end of the molding wedge. Preferably, the angle α is about 90 °.

  Referring again to FIG. 3, the extended surface 62 intersects the web surface 60 along the line 74 to form a common edge between the web surface 60 and the extended surface 62 and includes the root 18. It extends downward from the horizontal plane. When the line 74 is a straight line (for example, the web surface 60 and the extended surface 62 are flat), the line 74 is preferably horizontal. However, as described above, in some embodiments, the line 74 may be inclined with respect to a horizontal plane. In FIG. 3, the extended surface portion 62 may be curved, flat, or a combination thereof, as in the case of the web surface portion 60 represented by a plane in terms of drawing. The extended surface portion 62 is preferably a flat surface. The perpendicular 78 facing outward with respect to the extended surface portion 62 has a component facing downward. Toward the outside means that the perpendicular line is away from the vertical plane intersecting the root 18. As clearly shown in FIG. 6, the angle β between the surface normal 76 and the surface normal 78 in a vertical plane passing through both the web surface 60 and the extension surface 62 is less than about 30 °. However, it is preferably greater than about 15 °, less than about 25 °, but more preferably greater than about 20 °. In this way, the glass stream on the web surface 60 “breaks” at the line 74 and changes direction as it flows over the extended surface 62. This can be seen in FIG. 6, where the angle β changes the direction of the glass flow in the vertical plane containing the surface normals 76, 78, ie on the web surface 60 represented by the arrow 75. The flow changes to a flow on the extended surface portion 62 represented by the arrow 77.

  In order to ensure that the flowing glass sheet is formed substantially flat, the inner edge 80 of the extension surface 62 and the inner edge 80 of the extension surface 62 opposite the opposite side of the forming wedge 10 are both Since the inner edge 80 is in a vertical plane passing through the root 18, it forms an overlapping common line or stretched line. Such an inner edge 80 preferably forms a common line extending from a point 70 on the root 18 to a lowest point 82 on a line 80 in a vertical plane passing through the root.

  Since the extended surface portion 62 is a thick sheet essentially made of a heat-resistant material having an appropriate shape, the extended surface portion 62 may be formed of a substantially three-dimensional body in which one surface of the polyhedron becomes the extended surface portion 62. preferable. That is, this polyhedron has similar dimensions in three directions. For example, the extended surface portion 62 is one surface of a polyhedron. Although this polyhedron (shown in FIG. 3 is an inverted three-sided pyramid) may be hollow, a core made of an insulating material that slows the heat dissipation by the extended surface 62 against the glass flowing on the extended surface 62. It is preferable to provide. For example, the polyhedron can comprise a core that includes an insulating fiber such as a high alumina content Saffil® fiber, however, although it has a higher thermal conductivity than a less dense material, such as zirconium. A denser heat-resistant material (that is, a material that can withstand high temperatures) may be used. Although it is not desirable for the glass flowing over the edge guides to cool, dense materials such as zirconium that increase the heat conduction from the glass can be covered with a heat-resistant cover such as platinum or a platinum alloy or support the glass flow. This has the advantage of providing a polyhedron having structural integrity.

  The extended surface portion 62 may further include one or more heaters to minimize heat loss due to the glass flowing over the extended surface portion. These heaters may be arranged so that the temperature distribution of the glass flow is adjusted. In a more preferred embodiment, the web surface can be lined with an insulating material and a heater can also be provided. That is, the insulating material can be used to fill the space between the web surface portion and the converging surface portion behind it. The heater may be attached to the back surface of either or both of the web surface portion 60 and the extended surface portion 62. When a core is employed, a plurality of heating elements may be distributed inside the core material. Such a heater may be individually controlled so that a predetermined specific temperature distribution is obtained with respect to the glass flow flowing on the surface portions 60 and 62.

  In view of the fact that the four edge guides used for one molding wedge have the same structure, only one such edge guide will be described for each embodiment.

  As previously described, the edge guide 54 with portions 58, 60 and 62 is a cast refractory composition or suitable refractory metal, such as stainless steel, platinum, platinum rhodium alloy, or other high temperature alloys. It can be formed from a composition.

  The edge guide according to the present invention can produce a maximum width glass sheet with a minimum amount of edge beads. The edge guide is adjacent to the edge portion 58 while reducing the thickness of the edge portion of the glass flow, with one protruding surface 58 for the edge portion of the molten glass flowing along the forming wedge. One web surface 60 for maintaining the flow of molten glass and one extended surface 62 for further reducing the thickness of the glass flow and maintaining the overall sheet width are provided.

  Molten glass flowing down along the converging forming surface 40 is captured by the web surface 60 along a diagonal that intersects the inclined forming surface. The glass sheet flowing downward is supported by the inclined molding surface first and then by the web surface portion 60 of the edge guide 54 so as to be guided. The web surface portion 60 has a function of maintaining the full width of the glass flowing down to the bottom outer edge of the web surface portion and a substantially vertical flow.

  The contour of the web surface portion 60 whose horizontal length is longer than that of the molding surface 40 captures the glass stream flowing over it, thus providing a wetting length that increases the width, i.e. reduces the thickness, thus. The thickness of both edges in the longitudinal direction of the molten glass stream is actually reduced before the molten glass stream leaves the bottom edge of the web surface.

  After leaving the web surface portion 60, the glass flow breaks at line 74 and flows at a negative angle β relative to the web surface portion 60, as shown in FIG. The central portion of the glass stream continues to flow and converges along the stretch line formed by the inner edge 80 and root 18 so that both outer edge portions of the opposing extended surface portion that branches off reduce the thickness of the glass sheet.

Concrete example

One embodiment of the present invention was performed using a high-viscosity oil instead of molten glass and a scale model of a wedge-shaped molded body as shown below. The length of the wedge-shaped molded body was 165.1 cm. The dimensions of each web surface were about 27.9 cm in length of edge 64 and about 14.9 cm in length along cross line 74. The dimensions of each extended surface are such that the edge length along the cross line 74 is about 14.9 cm, the angle between the edge along the cross line 74 and the edge 80 is about 51 °, and the cross line 74 The angle between the edge along the edge and the edge 64 was about 71 °, and the angle between the edge 80 and the edge 64 was about 58 °. The oil had a viscosity of 1,394 Pa · s (13,940 poise) and a density of 905 kg / m ^{3 at} a temperature of 22.2 ° C. A pair of opposing pulling rollers 86 are disposed at a distance of approximately 5.08 cm below the lowest point 82 of the extended surface at each edge of the oil sheet (measured to the top of the roller) and these rollers are made of viscous oil. It was simultaneously rotated in a direction to support downward flow. The oil was run at a rate of 138.8 kg / hr (306 lb / hr). As shown in FIG. 7, the distance d from the inner edge of the ridge surface 58 (ie, line 88) to the oil sheet edge 90 at a predetermined point below the pulling roller is in accordance with an embodiment of the present invention. It was measured using both the web surface and the extended surface. Both the web surface portion and the extended surface portion were planar surfaces in contact with oil. A second measurement is made using the prior art shown in FIG. 2 and is hereinafter referred to as a “standard” structure. The standard structure used a web surface portion having a curved surface that extends seamlessly down to the bottom of the root. The measurement results are shown in Table 1 below. In order to control the flow of oil over the molding surfaces 38, 40, the edge surface was used during all measurements. Table 1 shows that using the extended surface portion 62 of the edge guide 54 increases the overall increase in sheet width when compared to the standard structure. d (and hence Δd) represents the measured value at one edge of the sheet.

To measure the increase in usable sheet width, from multiple points on a vertical line 92 that is on the glass surface below the root 18 and passes through the furthest point on the web surface (ie, point 70). The distance D to the potentially usable boundary was measured as indicating the usable sheet width along one edge of the sheet. What we call here a potentially usable glass is a glass that is potentially useful for commercial use in purposeful applications such as for the production of liquid crystal displays or organic liquid crystal displays. One skilled in the art will recognize that this is the case. Potentially usable glass as used herein is glass that has not contacted the edge guide. The boundary line 94 for potentially usable glass can be determined by inserting a marker, such as a dye or an individual object, into the glass stream at point 70. In the present embodiment, an individual marker is inserted into the oil at point 70. A camera placed at right angles to the oil flow was used to image the flow of the marker descending. Measurements were made on appropriately scaled photographs. In Table 2, a negative value is when the usable glass boundary 94 is on the left side of the line 92, and a positive value indicates that the usable glass boundary 94 is on the right side of the line 92. The measured value when using the edge guide according to the above was compared with the measured value when using the standard structure. Compared to the results obtained from Table 1, the amount of potentially usable increase in glass is much greater than the increase in sheet width. That is, the edge guide according to the present invention has a uniformly large gain in usable glass while allowing the sheet width to be increased for a given molding surface length.

  In yet another embodiment, the first extension surface is removably attached to the first web surface portion 60, as shown in FIG. A portion 62 is provided. FIG. 8 shows a first extended surface portion 62 that is separated from the first web surface portion 60. The first extension surface may be connected to the first web via one or more ant joints, such as an exemplary ant joint 96 with male and female components 98 and 100, respectively, as shown in FIG. Can be attached to the surface. The male and female components of the ant joint are interchangeable between the web surface portion 60 and the extended surface portion 62 of the edge guide of the present invention. However, it is preferred that the female ant joint element 98 is machined into the web surface 60 and the male component 100 is machined into the extended surface 62. As an alternative embodiment, a plurality of pins (not shown) can be used to attach the extension surface 62 to the web surface 60, and these pins are embedded in the first extension surface 62; And it is preferable to have a size that fits into a receiving hole in the web surface portion 60. Where pins are used, it is desirable to provide means for securing or clamping the extended surface to the web surface. These clamping means are conventionally known suitable, such as C-clamps or their equivalents that can clamp flanges (not shown) on surfaces that are not covered by glass on the extension and web surfaces. It may consist of various methods.

  In a normal manufacturing environment, damage may occur to the edge guides, in particular the extended surface 62 extending below the root 18. Repair of damaged parts generally requires stopping production activities and cooling the forming wedges. When the repair is complete, the forming wedge must be reheated to the proper operating temperature in a manner that avoids thermal distortion that damages the forming wedge. The entire cooling-repair-reheating cycle is long, during which the production line cannot produce usable glass. By making the extended surface 62 removable, the edge guide can be repaired during operation of the forming wedge (ie during glass manufacture), thus avoiding long, costly down periods. be able to. For example, by changing the flow rate, the glass sheet can be manipulated to stop the sheet from flowing over the web surface portion 60 and the extended surface portion 62 away from the ends of the forming wedge. As is conventionally known, the extended surface portion 62 can be removed from the web surface portion 60 by removing one or more dovetail joints. When the repair of the damaged extension surface is complete (or the damaged extension surface is replaced with a new extension surface), the repaired portion can be reattached to the appropriate web surface.

  The use of the detachable extension surface has the advantage that the forming wedge 10 can be easily machined and the edge guides above the root 18 can be made of a single material. For example, the forming wedge 10, the regulating dam 48, the web surface 60 and the protruding edge 58 can be obtained by machining a single material made of a heat-resistant material. / The structure of the edge guide can be greatly simplified. The parts of the molding apparatus that are most susceptible to damage, i.e., the extended surface 62, are attached and / or removed as needed.

  When a dovetail joint is used as a method of attaching the extended surface portion 62 to the web surface portion 60, the extended surface portion 62 can be removed and / or replaced from the “outside” of the forming wedge for ease and safety. It is preferred (but not essential) that the dovetail joints extend substantially parallel to the longitudinal direction of the forming wedge. That is, from the “outside” is from outside the ends of the forming wedge so as to maintain a safe distance from the glass that continues to flow over at least a portion of the weir 36.

  It is emphasized that any of the above-described embodiments of the present invention, and in particular the "preferred" embodiments, are merely possible examples and are merely illustrative for a clear understanding of the principles of the invention. Should be. Many variations and modifications can be made to the embodiments of the invention described above without departing from the spirit and principles of the invention. All such modifications and changes are intended to be included herein within the scope of this specification and the present invention and protected by the following claims.

The perspective view which cut off some conventional edge guide bodies The perspective view which cut off some conventional edge guide bodies The perspective view which cut off a part of apparatus for extending | stretching the glass sheet by embodiment of this invention which shows the structure of the edge guide body by embodiment of this invention Side view of the device of FIG. 3 is a plan view of the apparatus of FIG. 3 showing the angle formed by opposing web surface portions A vector diagram of the angle between the normal to the web surface of the device of FIG. 3 and the normal to the extension surface, with both normals on a vertical plane through the extension surface and the web surface. 3 is a side view of the apparatus of FIG. 3 shown with edge pulling rollers and measurement distance The perspective view which cut off a part of glass sheet extending | stretching apparatus by embodiment of this invention which shows the detachable extended surface part of an edge guide body Sectional view showing a typical dovetail joint that can be used to attach the extension surface to the web surface of the edge guide

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Molding wedge 18 Root 32 Groove 36 Overflow weir 38, 40 Molding surface 44 Molten glass 54 Edge guide 60 Web surface 62 Extension surface 76, 78 Perpendicular

Claims (10)

An apparatus for drawing a glass sheet downward,
A molding wedge having a pair of downwardly inclined molding surfaces, wherein the downwardly inclined molding surface converges at the bottom of the molding wedge to form a root and A forming wedge that defines a glass stretch line along the
A first web surface portion adjacent to the molding surface portion for capturing the flow of glass along the edge of the molding surface portion and reducing the thickness, where is a perpendicular to the web surface portion? A first web surface portion that is also horizontal, and a first extended surface portion that intersects the first web surface portion and extends below the first web surface portion,
With
An outwardly directed perpendicular to the first extended surface has a downwardly directed component;
The apparatus for extending | stretching a glass sheet below characterized by the above-mentioned.   The normal of the first extended surface portion is about 15 ° and about 15 ° with respect to the normal of the first web surface portion in a vertical plane passing through the first web surface portion and the first extended surface portion. 2. An apparatus according to claim 1, characterized in that it forms an angle [beta] between 30 [deg.].   The apparatus according to claim 1, wherein an inner edge of the first extended surface portion is in a vertical plane including the root.   4. The apparatus according to claim 3, wherein an inner edge of the first extended surface portion overlaps an inner edge of the second extended surface portion, and an overlapping portion of both inner edges is in the vertical plane.   The apparatus of claim 1 wherein the first web surface is substantially planar.   A planar second web surface portion is disposed opposite the first web surface portion on the opposite side of the molding wedge, and a plane parallel to the first web surface portion is the second web surface portion. 6. The apparatus of claim 5, wherein the angle is about 90 [deg.] With respect to a plane parallel to the web surface.   The apparatus of claim 1, wherein the first web surface and the first extended surface intersect along a straight line. An apparatus for stretching a glass sheet,
A molding wedge having a pair of downwardly inclined molding surface portions, wherein the downwardly inclined molding surface portion converges at the bottom of the molding wedge to form a root and A forming wedge that defines a glass stretch line along the edge, and an edge guide that extends along a vertical edge of the forming wedge, the edge guide further comprising the forming wedge A substantially flat web surface portion connected to the molding surface portion for capturing the glass flow along both edge portions of the sheet and reducing the thickness thereof, and crossing the web surface portion and below the web surface portion An edge guide, which has a substantially planar extension surface extending to the web surface, the web surface having a horizontal surface normal everywhere;
The perpendicular to the extended surface portion has a component facing downward,
An apparatus for stretching a glass sheet.   The normal to the web surface and the normal to the extension surface form an angle β between about 15 ° and about 30 ° in a vertical plane passing through both the web surface and the extension surface. 9. A device according to claim 8, characterized in that A method for creating a glass sheet,
A step of extending a glass sheet downward from a molding wedge having a pair of downwardly inclined molding surfaces, wherein the downwardly inclined molding surface converges at the bottom of the molding wedge A process that is
A step of flowing a glass sheet on the web surface portion connected to the molding surface portion, wherein the perpendicular to the web surface portion is horizontal everywhere, and on the extended surface portion intersecting the web surface portion A step of flowing the glass sheet, wherein the extended surface portion has an outwardly directed perpendicular with a component facing downward;
A method for producing a glass sheet.

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