KR20110047164A - Low friction edge rolls to minimize force circulation - Google Patents

Abstract

PURPOSE: A low frictional edge roll for minimizing the circulation of force is provided to eliminate friction generated in the driving part of an assembly in contact with glass ribbon in order to reduce the circulation of the force. CONSTITUTION: A low frictional edge roll includes a molding body(12), a shroud(22), an edge roll assembly, and a second seal plate. The molding body supplies glass ribbon(20). The shroud includes a first seal plate and forms a drawing chamber. The pressure of the drawing chamber is a first pressure. The edge roll assembly includes a rotatable shaft and a contact surface. The shaft is expanded to the drawing chamber using the shroud. The contact surface is in contact with the edge of the glass ribbon.

Description

Low Friction Edge Roll to Minimize Force Cycling

The present invention is directed to a method of reducing the circulation of forces in a glass drawing process. Glass drawing devices have also been disclosed that reduce the circulation of force.

One method of forming a thin sheet of glass is a drawing process, in which a ribbon of glass is drawn from a reservoir of molten glass. This configuration is achieved, for example, through an up-draw process in which the ribbon is drawn upwards from the reservoir (ie Foucault or Colburn), or in a down-draw process where the ribbon is typically drawn downward from the molded body. (down-draw process) (ie slot or melt). Once the ribbon is molded, individual sheets of glass are cut out of the ribbon.

In a conventional downdraw process, molten glass is formed from a glass ribbon contained within a drawing chamber, which is formed by a shroud surrounding the ribbon. Among the various components, shrouds are used to maintain a constant thermal environment in the area formed by the shroud and the surrounding ribbon. The roller pair passes through the shroud and grips the glass ribbon edge. The rollers are used to apply tension to the ribbon, to apply transverse tension to the ribbon, or just to guide the ribbon. Thus, rotational force is applied to the roller by the motor, or the roller is applied to the roller by the lowering rotational force, the roller may be free-wheeling. In either case, the roller rotates. Typically the production roller mechanism allows the roller to move in the horizontal and / or vertical direction from the glass contact area. This configuration allows the geometrical tolerances of the rolls, run-out and variations in tolerances during operation to be acceptable, depending on the normal variation in glass thickness. Moreover, for access to maintenance, restarting the process, and for many practical tasks, the rolls are typically moved by production roll mechanisms so that they are typically spaced from the glass. Friction forces that prevent free movement of the edge rollers can lead to a circulation of forces, which is an undesirable perturbation of the ribbon that can solidify into the glass as the glass is displaced from the viscous material to the elastic material. Or stress change. Another feature of the production roller mechanism is to minimize air leakage from the drawing chamber. Inadequate seals through which the shaft of each roller (roll) passes through the shrouds allow excess flow to exit the shrouds-to continue to heat the surrounding environment-and to increase the relatively cold gas flow entering the shroud bottoms. In particular, many edge roll seal leaks that change over time can prevent the ribbon from cooling optimally and can cause undesirable stress and distortion in the final product. Thus, the seal simultaneously withstands the high temperature shroud and the internal environment of the shroud, minimizes the outflow of high temperature air pressure from the inside of the shroud, and centers the displacement of the roller shaft and the axis along the shaft longitudinal axis. Rotational movements must be possible. In general, such seals include a metal-on-metal interface that induces frictional forces to the drawing device.

A glass ribbon drawing device, in particular a device having a reduced circulation force resulting from friction of the glass ribbon drawing device, is disclosed, which glass ribbon drawing device can exhibit a shape or stress in the glass sheet cut out from the glass ribbon. . This reduction in force circulation can be achieved by eliminating the friction that occurs between the moving parts of the assembly that contacts the glass ribbon, especially during the time the glass ribbon transitions from the viscoelastic state to the elastic state. This zone, known as the set temperature range, is the temperature range, beyond which the glass reaches a viscous state that allows the stress transferred to the glass to solidify into the glass. Also disclosed is a method by which glass ribbon can be drawn from the drawing device.

In one embodiment, a glass ribbon drawing device is disclosed, the drawing device comprising a molded body for supplying a glass ribbon, a shroud disposed relative to the glass ribbon and forming the drawing chamber, the shroud being a first seal A plate and has an atmospheric pressure, a first pressure, P _{s in} the drawing chamber. The drawing device further comprises an edge roll assembly, the edge roll assembly comprising a rotatable shaft extending through the shroud to the drawing chamber, a contact surface disposed on the shaft in contact with the edge of the glass ribbon in the drawing chamber, and the A second seal plate connected to the shaft, wherein a gap is formed between the first seal plate and the second seal plate, and a gas is injected into the gap so that the air pressure in the gap is equal to the first pressure P _s . Maintained at a second pressure P _g equal to or less than, the first seal plate comprises a slot, through which the shaft extends to a drawing chamber which allows the shaft to move across the longitudinal axis of the shaft. The gas is preferably injected into the gap through a passage formed in the first seal plate, which passage is open at the surface of the first seal plate facing the second seal plate.

The molded body may be, for example, a fusion-style molded body consisting of a trough containing molten glass material and a converging molding surface. The molten glass flows in a separate stream on the forming face that overflops the troughs and converges, and recombines or fuses in the line where the converging forming faces meet. Optionally, the shaped body includes a slot through which the glass ribbon is drawn. In other embodiments the shaped bodies can be used as used in Foucault processes.

In another embodiment, the drawing device comprises a third seal plate positioned such that the shaft passes through an opening formed in the third seal plate and the second seal plate is disposed between the first seal plate and the third seal plate. Include. The third seal plate also includes a gas passage that is open on the third seal plate side facing the second seal plate through which gas is injected into the second gap. In any other embodiment, the spring member is positioned between the second seal plate and the third seal plate. The spring member may be used in connection with the gas injected between the second seal plate and the third seal plate, or may be used in connection with the gas injection position.

Preferably, the first gap between the first seal plate and the second seal plate is approximately 0.254 cm or less and the coefficient of friction between the first seal plate and the second seal plate is less than 0.4. For example, the first seal plate or the second seal plate may be made of graphite having high temperature thermal tolerance, boron nitride, or layers of various low friction materials.

To further reduce the friction in the edge roll assembly, the shaft is supported using an air bearing that causes the shaft to displace in a direction transverse to the shaft longitudinal axis. Air bearings (ie more generally gas bearings) may support the displacement or rotation, depending on the design of the edge roll assembly. For example, the shaft may translate in a direction transverse to the longitudinal axis of the shaft, or the shaft may continue to move transversely in an arc.

In another embodiment, a drawing device for a glass ribbon is disclosed, the drawing device including a molded body for supplying a glass ribbon, a shroud and an edge roll assembly forming a drawing chamber and disposed about the glass ribbon, The air pressure in the drawing chamber is the first pressure P _s . The edge roll assembly includes a rotatable shaft extending through the shroud into the drawing chamber, a contact surface disposed on the shaft in contact with the edge of the glass ribbon in the drawing chamber, and the shaft in a direction transverse to the longitudinal axis of the shaft. A gas bearing adapted to displace and connected to the shaft. The seal assembly also includes a first seal plate fixed to the shroud and a second seal plate connected to the shaft, a gap is formed between the first seal plate and the second seal plate, and gas is injected into the gap. To maintain a pressure in the gap at a second pressure P _g equal to or less than the first pressure P _s , wherein the first seal plate comprises a slot through which the shaft extends into the drawing chamber. And the slot allows translation of the shaft across the longitudinal axis of the shaft. Either or both of the first and second seal plates comprise graphite, boron nitride, or layers of various low friction materials with high temperature tolerances. It is preferred that the coefficient of friction between the opposing faces of the first seal plate and the second seal plate is less than 0.4.

In another embodiment, the glass ribbon drawing method is described as including a method of drawing a glass ribbon from a molded body, wherein the glass ribbon passes through a drawing chamber formed of shroud disposed relative to the glass ribbon, and the shroud Includes a first seal plate, and the air pressure in the drawing chamber has a first pressure P _s . The glass ribbon contacts the edge roll assembly, wherein the edge roll assembly is a rotatable shaft extending from the first seal plate through which the shaft can move in a direction transverse to the longitudinal axis of the shaft through the passageway to the drawing chamber, the always shaft And a second seal plate associated with the shaft to rotate with the contact surface disposed on the shaft in contact with the edge of the glass ribbon. As the pressurized gas is injected into the first gap between the first seal plate and the second seal plate, the second pressure P _g which is the atmospheric pressure in the first gap is equal to or less than the first pressure P _s . The second seal plate rotates relative to the first seal plate. A pressing force is interlocked with the shaft, and the pressing force is applied to the shaft laterally. This configuration generates a gripping force between the pair of rolls, which is necessary to minimize roll slipping and is a key contributor to the tension applied to the glass ribbon by the roll. The shafts (and various parts of the edge roll assembly) are replaced in accordance with ribbon edge thickness changes or dimensional changes in the installation. Friction from the seal plate causes a change in the actual pressing force applied to the shaft-glass interface as the roll moves. If the seal plate friction is reduced, the roll can move with minimal change with respect to the pressing force. Preferably, the coefficient of friction between the opposing faces of the first seal plate and the second seal plate is 0.4 or less.

Preferably, the maximum frictional force that prevents shaft displacement is 2.3 kg or less, such that the contact surface exerts a substantial contact force on the glass ribbon during operation. In addition, when the shaft is supported by the gas bearing, the friction reducing effect is improved.

In any other embodiment, the edge roll assembly may be adapted to replace the third seal plate disposed opposite the first seal plate such that the second seal plate rotates between the first seal plate and the third seal plate. It includes more. Gas may also be injected in the second gap between the second seal plate and the third seal plate.

The drawing device further comprises an air bearing and a seal assembly for supporting the edge roll shaft, the seal assembly comprising a first seal plate fixed to the shroud and a second seal plate fixed to the shaft, the gap being the first seal plate. A gas formed in the first seal plate and the second seal plate, and gas is injected into the gap to maintain the air pressure in the gap at a second pressure P _g equal to or less than the first pressure P _s , The seal plate includes an elongate slot, the shaft extending through the elongate slot into the drawing chamber, the elongate slot allowing the shaft to move across the longitudinal axis of the shaft. Preferably, the gap between the first seal plate and the second seal plate is about 0.254 cm or less. The slotted first seal plate (or inner seal plate associated with the glass ribbon) enables lateral movement of the edge roll shaft.

Gas is injected through the passage formed in the first seal plate, which passage is open at the surface of the first seal plate facing the second seal plate. The injected gas is preferably air, but can be any other gas such as nitrogen or helium or mixtures thereof.

In various embodiments, the third seal plate is positioned such that the shaft passes through the opening of the third seal plate and the second seal plate is disposed between the first seal plate and the third seal plate. The third seal plate includes a gas passageway, ie, a port, open at the side of the third seal plate facing the second seal plate. Optionally, a spring member may be positioned between the second seal plate and the third seal plate.

One or a combination of the first seal plate, the second seal plate and / or the third seal plate may reduce friction, for example, when contact occurs between the boron nitride coating, graphite material, or the seal plate. It can include a coating that can be.

In another embodiment, a glass ribbon drawing method is disclosed comprising forming a glass ribbon by a drawing process, wherein the glass ribbon passes through a drawing chamber formed of shroud disposed relative to the glass ribbon, The shroud comprises a first seal plate and the air pressure in the drawing chamber has a first pressure P _s .

The method further comprises contacting the glass ribbon with the edge roll, which edge roll extends through the elongate passageway into the drawing chamber in a first seal plate from which the shaft can move across the longitudinal axis of the shaft. A rotatable shaft, and a ceramic contact surface disposed on the shaft in contact with an edge of the glass ribbon, the rotatable shaft including a second seal plate fixed to the shaft. Rotating with the shaft, the plane of the second seal plate is in a state perpendicular to the longitudinal axis of the shaft.

As the pressurized gas is injected into the first gap between the first seal plate and the second seal plate, the second pressure P _g , which is the air pressure in the first gap, becomes equal to or less than the first pressure P _s , The second seal plate rotates relative to the first seal plate.

In various embodiments, the third seal plate is disposed opposite the first seal plate such that the second seal plate rotates between the first seal plate and the third seal plate. Gas such as air nitrogen or helium may be injected into the second gap between the second seal plate and the third seal plate.

The present invention will be more readily understood, and various objects, features, details and advantages of the present invention will be readily understood without reference to the detailed description set forth below and the accompanying drawings. Could be. It will be appreciated that all such additional systems, methods, features and advantages are included within the scope of embodiments of the present invention, within the scope of the present invention, and within the scope of the appended claims.

1 is a side cross-sectional view of an exemplary fusion downdraw process in accordance with an embodiment of the present invention.
2 is a side cross-sectional view of a pair of edge roll assemblies associated with a glass ribbon.
3 is a cross-sectional view of an edge roll and seal assembly according to one embodiment of the invention.
4A is a side view of the seal plate of FIG. 3 with a linear slot receiving a roll shaft.
4B is a side view of the seal plate of FIG. 3 with an arced slot receiving a roll shaft.
4C is a side cross-sectional view of an edge roll assembly that includes a counterweight and is positioned such that the roll shaft moves through an arc.
5 is a side cross-sectional view of the seal assembly showing a gas passage for delivering gas to one side of the seal plate.
6 is an exploded perspective view of another embodiment of a seal assembly according to one embodiment of the present invention including three seal plates.
FIG. 7 is an edge cross sectional view of the seal assembly of FIG. 6 showing a gas passage and gas flow. FIG.
8 is a side cross-sectional view of the variant seal assembly of FIG. 7 using a spacer member between several seal plates.
9 is a plan view showing a pair of edge rolls engaged with the edges of the glass ribbon (air bearings connected with the edge roll shaft through the support member are shown and a seal assembly is used).
10 is a cross-sectional view of another embodiment of a seal assembly using a spring between several seal plates.

In the following detailed description, for purposes of illustration only, examples that disclose specific details have been described to aid the understanding of the present invention. However, one of ordinary skill in the art having the benefit of the present invention will appreciate that many other embodiments may be made within the scope of the specific embodiments disclosed herein. Moreover, descriptions of well-known devices, methods and materials may be omitted to clarify the description of the invention. As a result, in either embodiment, it can be seen that the same reference numerals are used to indicate the same components.

It is necessary to carefully control all manufacturing processes to draw thin ribbon material to form a glass sheet having a thickness of about millimeters or less with the exact standard flatness required for modern display industries such as televisions and computer monitors. However, special care is needed during the time interval during which the glass ribbon transitions from the viscous state to the elastic state. Even small changes in force on the air ribbon, which may be caused by air flowing in the drawing area or by vibration of the mobile installation, may indicate perturbations on the original flat surface.

In an exemplary fusion-type downdraw process, molten glass is supplied to a shaped body, which includes an open channel at the top of the upper surface of the shaped body. Molten glass overflows the walls of the channel and flows down the converging outer side of the molded body until a separate flow meets in a line (ie "root") that meets the converging surface. The separate flows are combined or melted so that the separate flows are a single ribbon of glass flowing down from the shaped body. Various rollers (or “rolls”) located along the edge of the ribbon are used to draw or pull the ribbon down and / or to apply tension to the ribbon to help maintain the width of the ribbon. That is, while several rolls are rotated by a motor, the other roll is a free wheel.

As the ribbon is lowered from the molded body, the molten material transitions from the viscous state at the bottom of the molded body to the visco-elastic state and finally to the elastic state. When the ribbon is cooled to an elastic state, the ribbon is scored along its width and separated along the score line to produce a separate glass sheet.

During the time that the glass ribbon is in a fluid, viscous state, the stress applied to the molten material immediately disappears. However, as the ribbon cools and the viscosity increases, the induced stress does not quickly disappear until the temperature range at which the induced stress is received by the glass and the ribbon shape is maintained in the glass is reached. This is the source of undesirable acceptance stresses and distortions in the final product. Therefore, during the time under stress and hardened into glass, it is preferable that an external force is applied to the glass ribbon as constantly as possible. The reason for this force change is in the edge roll. It can be seen that the change in force due to the edge roll results in a change in glass thickness and various product properties. It can be seen by experience that keeping the external force constant is important for achieving the lowest stress and highest flatness of the LCD substrate sheet, for example.

Although the shape of the edge rolls is different, in each case a pair of rolls can hold or grasp the ribbon. Several pairs of rolls are located at opposite edges of the ribbon so that for a particular vertical position along the length of the ribbon (ie distance from the root), two pairs of edge rolls are used. The edge rolls can be driven, for example, by electric or hydraulic motors, or the edge rolls can be freewheeling wheels. The edge rolls share their common shafts at the edges facing the edges so that the shafts extend across the width of the ribbon, or each edge roll extends only as necessary to position the roll contact surface at the distal end of each roll shaft. It has a separate shaft. This contact surface is designed to withstand long periods of time, sometimes in excess of 800 ° C., caused by contact with the glass ribbon, preferably using a ceramic material. Moreover, the shaft of the edge roll need not be horizontal (direction across the drawing direction), but can be inclined with respect to the horizontal direction to increase the tension across the width of the ribbon.

Each pair of edge rolls is designed to accommodate a gap that varies between the contact surfaces of the edge rolls. For example, each contact surface need not preferably be concentric with the shaft when attached to the shaft, causing runout as the roll rotates. Moreover, the machining tolerances for shaft straightness and distortion at operating temperatures result in an operable runout. Moreover, the roll is designed to withstand small variations in the thickness of the ribbon edges. This lateral (horizontal) movement of the edge rolls occurs as the ribbon descends between the roll pairs. That is, the pairs of tension rolls must be spaced apart in the horizontal direction and are pulled closer together once again as the tension rolls operate. The production edge roll mechanism allows this movement during roll operation, but is designed to keep the gripping force applied to the glass constant. Preferably, the roll is pressed inward toward the plane of the glass ribbon by the pressing force. This pressurization creates the gripping force between the pair of rolls necessary to minimize roll slip and is a major incentive to the tension exerted on the glass ribbon by the roll. The mechanism for applying this pressing force should enable the inside and outside movement (widening of the gap between the edge roll pairs) from the runout cause portion described above. For example, the edge roll includes a lever and a fulcrum arrangement for translating the edge roll shaft laterally. The counterweight can be used to apply sufficient force to the lever so that the edge roll contact surface can grip the glass ribbon, but the roll can move across the ribbon plane, for example, by changing the contact surface eccentricity. However, several methods of applying a pressing force are to use such as springs arranged to press or pull the roll assembly along a given movement line. The main concern with manufacturing roll systems is that the friction in the roll mechanism slide and bearing—along with the friction in the seal plate—disperses undesirable variable forces that inhibit movement and change the gripping forces applied to the glass. For example, by accurate measurement of the roll horizontal force imparted to the ribbon, a change in force in excess of 10 lbs is shown during the roll rotation cycle. Similarly, normal tensile forces can be affected by this same source.

As the ribbon is lowered from the molded body, the edge roll moves in a direction transverse to the plane of the glass ribbon due to a small variation in the ribbon edge thickness or, for example, the eccentricity of the edge roll contact surface. The pressing force maintains contact between the roll contact surface and the glass ribbon edge. However, system friction prevents these movements. In extreme cases, if the tension roll pair is held in place and only the roll contact surface can rotate, the system will be severely modified by the ribbon. For example, if one or both contact surfaces are not centered with their respective shafts, each rotation of the contact surfaces will exert a circular force on the ribbon. This circular force gives a direct impact from ribbon stresses that change over time. Thus, the frictional force in the edge roll assembly acts to reduce the stress change that can affect the shape (ie flatness) of the glass sheet separated from the ribbon.

1 shows an exemplary fusion downdraw apparatus 10 including a shaped body 12, which comprises a forming surface 16 converging with a channel, ie a trough 14. Converging shaping surfaces 16 meet at the root 18. Molten glass is supplied to the trough 14 from a source (not shown), the molten glass overflows the walls of the trough and descends on the outer side of the shaped body as a separate stream. A separate stream of molten glass flowing over the converging shaping surface 16 forms at the root 18 and forms a glass ribbon 20 flowing downward 21.

When the thickness and viscosity of the glass ribbon 20 is finally achieved, the glass ribbon is separated across its width to provide an independent glass sheet or pane. As the molten glass continues to feed into the molded body, and as the glass ribbon lengthens, additional glass sheets are separated from the ribbon.

The shroud 22 surrounds the upper range of the ribbon 20 under the root 18 and is connected with the upper enclosure 24 which receives the shaped body 12. Shroud 22 is used as the platform, where various heating and / or cooling facilities are located to adjust the temperature of the ribbon. However, as the highest temperature occurs at the top of the shroud-due to the buoyancy of the hotter air inside the shroud, the internal pressure rises over the height of the shroud. Openings and leaks in the shroud 22 wall result in upward inward air flow from the shroud base and typically have a significant impact on the thermal environment within the shroud. Excessive leakage may exceed the properties of the heating installation to satisfy the optimum ribbon temperature, resulting in stress and distortion in the final product. Changes in air leakage can result in changes in general and / or local shroud cooling rates, which can result in stress or distortion in the final product. For successful production sheet drawing, it is important for openings and leaks to be minimized and kept constant over time.

An edge roll assembly 26 is positioned at a predetermined vertical position below the root 18 and includes a driven edge roll, which guides the ribbon and keeps the tension constant across the ribbon width. Is used to apply tension to non-driven idler rolls and / or ribbons. As described above, the rolls share a common shaft lying at the ribbon width, or each roll has its own shaft. Edge rolls are typically arranged in pairs, each roll of the roll pair being located on both sides of the glass ribbon edge. In addition, the edge roll pairs can be arranged in multiple pairs themselves, with a pair of rolls per ribbon edge placed in a given vertical position.

Edge roll assemblies with operable structures are controlled with typical manufacturing tolerances. For example, the edge roll contact surface in contact with the ribbon edge portion 34 may not be exactly concentric with each shaft. Or, the edge roll contact surface is not circular (ie locally flat). Or the edge roll shaft may not be perfectly linear during manufacture or operation. Like tires with distorted circles, these factors result in cyclical lateral displacement of the edge rolls, causing periodic movements each time the roll completes one rotation. Moreover, the ribbon edges (or “beads”) are slightly bulbous, and the thickness of the ribbon edges may vary along the length of the ribbon. In other words, the edge rolls of the edge roll pair may form a variable gap between the rolls.

Ideally, the roll mechanism may be designed such that the edge roll actuates and moves-keeping the gripping force constant between the roll pairs. In practice, however, the gripping force is changed by friction in the seal plate and the mechanism. As a result, the horizontal component and the vertical component of the roll force applied on the glass ribbon are changed. This circulation of roll force can have a direct impact on the product, such as stress or this stress change, torsional or torsional change, or glass thickness change.

FIG. 2 shows a part of the drawing device of FIG. 1 seen from one edge portion 34 of the glass ribbon 20. A pair of opposite edge roll assemblies 26 are shown, each edge roll assembly including a roll contact surface 40 connected to the edge roll support 42 via a roll shaft 44 and a shaft bearing assembly 46. do. Contact surface 40 is in contact with the ribbon at any vertical position of the ribbon, the ribbon comprising a viscous, visco-elastic or elastic portion, depending on the operation of the edge roll.

The edge roll support member 42 is thereby connected with the bearing 50. The bearing 50 is preferably a low friction bearing, preferably an air bearing such as a linear air slide or a rotating air bearing. The edge roll support 42 thus facilitates low friction movement of the edge roll support member 42 in the direction transverse to the vertical plane passing through the root 18, as indicated by arrow 52. A pressing force, such as the pressing force 54 shown in FIG. 2, is applied to the edge roll support 42 and acts in combination with the facing edge roll assembly to grip the glass ribbon between the edge roll pair contact surfaces 40. It will be appreciated that each edge roll support need not be moved simply as shown by arrow 52. For example, each edge roll assembly is configured to swing about an axis such that the edge roll contact surface moves arcuately from the ribbon (FIG. 4C). In this case, the bearing supporting the support 42 is designed to allow partial rotational movement, rather than linear movement , through the action of the counterweight 69 and gravity G.

3 shows a portion of the shroud 22 and the glass ribbon 20, which includes a ribbon edge 34. The shroud 22 includes a fixed first seal plate 56. Although the first seal plate 56 is shown as a separate plate, the first seal plate 56 may simply be part of the shroud itself. The first seal plate 56 extends through the thickness direction of the first seal plate and forms an elongate opening 58 formed in the plane 60 of the plate (see FIGS. 4A and 4B).

For example, as many of the edge rolls as possible outside the shroud are driven rolls (ie Every effort has been made to keep the driving force used in the mechanical positioning device of the edge roll or the electric motor or the hydraulic motor 28). However, this requires that the edge roll assemblies, especially the edge roll shafts, pass through the shrouds at their respective positions. Even without mitigation, this passage forms an opening that allows gas exchange between the shroud inner air pressure 30 and the shroud outer air pressure 32. In general, due to the influence of the high internal buoyancy, the air pressure 30 increases to the height of the shroud. The opening size and the outside pressure are controlled deeply around-since the opening at a higher position in the shroud generally increases the air flow from the base-disrupting the internal thermal environment. Thus, in order to prevent a higher temperature external gas outflow, the respective pressures are maintained at the same or slightly positive pressure as the internal air pressure (in relation to the external air pressure), and the rotational and lateral movements of the edge roll shaft are allowed in the It is highly desirable that the shaft passage be sealed. Typically, the air pressure inside and outside the shroud is air pressure.

Thus, the shaft 44 is supported by the bearing assembly 46 and includes a second seal plate 66 fixed to the shaft so that the second seal plate 66 rotates with the shaft 44. . The elongate opening 58 is designed to allow lateral movement of the shaft 44 (as indicated by arrow 68-see FIG. 4A). However, although the opening 58 need not be linear (straight), in some embodiments, since the lateral movement of the shaft includes a rotational component, it may include several curved portions (FIG. 4B).

As shown in FIG. 5, the first seal plate 56 also preferably includes a passageway 70 for receiving pressurized gas from a gas source (not shown). The supplied pressurized gas moves through the passage 70 and exits the first seal plate 56 through an orifice 72 formed on one side of the first seal plate 56. The orifice 72 is disposed opposite the second seal plate 66 such that the pressure P _g at the gap 74 between the first seal plate 56 and the second seal plate 66 is surrounded by a shroud. It may be adjusted to be equal to or less than the pressure P _s of the atmospheric pressure 30. As the second seal plate 66 rotates with the shaft 44, the gap 74 is preferably about 0.254 cm or less, more preferably, such that the first seal plate and the second seal plate are not preferably in contact with each other. Preferably about 0.127 cm or less.

The first seal plate 56 and the second seal plate 66 include a seal assembly 76 that prevents the outflow of hotter air pressure from the shroud. Moreover, the design of the seal assembly 76 can minimize the friction force generated if the first seal plate 56 and the second seal plate 66 are in contact and generate frictional forces that hinder the movement of the shaft 44. have. For this reason, it is preferable that one or both seal plates 56, 66 contain boron nitride, or several low friction materials (i.e. graphite) in case of contact. The coefficient of friction of steel to steel and steel to iron is typically measured in the range of approximately 0.4-0.8. On the other hand, the friction coefficient of graphite to steel, or boron nitride to steel, is typically <0.1. Such low friction material may be, for example, a coating or layer 71 on the potential contact surface of either or both of the first seal plate or the second seal plate.

6 is an exploded perspective view of another embodiment in which the seal assembly 76 includes a third seal plate 78. According to an embodiment of the present invention, the first seal plate 56 and the third seal plate 78 are formed in a box shape, and the second seal plate 66 is formed of the first seal plate 56 and the third seal. It is formed between the plates 78. Although FIGS. 6 and 7 show a first seal plate 56 having an “L” shaped edge that can provide the space needed to receive the second seal plate 66, this configuration is a seal plate 78. The first seal plate 56 may be kept flat, or the spacer member 82 may be included between the flat first seal plate 56 and the third seal plate 78. (See FIG. 8). Similar to the first seal plate 56, the third seal plate 78 includes an elongated passage 58, which allows lateral movement of the shaft 44 through the elongated passage. Additionally, the third seal plate 78 includes a gas port 84 to which pressurized gas is supplied and disposed to face the second seal plate 66. Gas flow is shown by arrow 43.

Furthermore, the pressurization provided in the passages of the first seal plate 56 and the third seal plate 78 to provide an adjustment pressure to the gap 74 between the first seal plate 56 and the second seal plate 66. Gas is used to generate a gas cushion between the first seal plate and the third seal plate and the second seal plate to minimize the possibility of contact between these first to third seal plates. This contact occurs, for example, as the shaft 44 moves along the shaft longitudinal axis 86. The gas supplied to the third seal plate 78 may also be used as a resistance to the pressure applied to the second seal plate 66 by the gas flowing out of the first seal plate 56.

9 is a plan view of a pair of edge roll assemblies 26 in which each contact surface 40 is arranged to grip the edge of the glass ribbon 20 between the contact surfaces. Also shown is each seal assembly 76.

In another embodiment shown in FIG. 10, the resistance to the force exerted by the gas flowing out of the first seal plate 56 is such that the gap between the second seal plate 66 and the third seal plate 78 ( 90 may be provided by a spring 88 located within. However, even if less friction continues to occur to form the glass ribbon than the friction that occurs between the two seal plates, this configuration is not so desirable because of the contact between the spring and the seal plate if contact with each other is allowed.

The present invention includes C1-C20 described below, but this is for illustrative purposes only, and C1-C20 are as follows.

C1. The drawing apparatus of a glass ribbon includes: a molded body for supplying a glass ribbon; A shroud forming a draw chamber and disposed against the glass ribbon (the shroud comprises a first seal plate and the air pressure in the draw chamber is a first pressure P _s ); Edge roll assembly; A second seal plate connected to the shaft; wherein a gap is formed between the first seal plate and the second seal plate, and the second air pressure in the gap is equal to or less than the first pressure P _s . Gas is injected to maintain at pressure P _g and the first seal plate comprises a slot, through which the shaft extends into a drawing chamber which allows the shaft to move across the longitudinal axis of the shaft. Wherein the edge roll assembly comprises: a rotatable shaft extending through the shroud into the drawing chamber; And a contact surface disposed on the shaft in contact with the edge of the glass ribbon in the drawing chamber.

C2. In connection with the drawing device according to C1, gas is injected through a passage formed in the first seal plate, which is open at the surface of the first seal plate facing the second seal plate.

C3. With respect to the drawing device according to C1 or C2, the drawing device passes through an opening formed in the third seal plate, and the second seal plate is positioned to be disposed between the first seal plate and the third seal plate. It further includes.

C4. In connection with the drawing device according to C3, the third seal plate comprises a gas passage open at the face of the third seal plate facing the second seal plate, through which gas is injected.

C5. In relation to the drawing device according to C3, the drawing device further comprises a spring member located between the second seal plate and the third seal plate.

C6. With regard to the drawing device according to C1-C5, the gap between the first seal plate and the second seal plate is about 0.254 cm or less.

C7. In connection with the drawing device according to C1-C6, the first seal plate or the second seal plate has a coefficient of friction less than 0.4.

C8. In connection with the drawing device according to C1-C7, the first seal plate or the second seal plate consists of a layer of graphite or boron nitride.

C9. In connection with the drawing device according to C1-C8, the shaft is connected with an air bearing in which the shaft is displaced in a direction transverse to the longitudinal axis of the shaft.

C10. A drawing apparatus of a glass ribbon includes: a molded body for supplying the glass ribbon; A shroud disposed relative to the glass ribbon and forming a draw chamber, where the air pressure in the draw chamber is a first pressure P _s ; An edge roll assembly comprising a rotatable shaft extending through the shroud into the drawing chamber; a contact surface disposed on the shaft in contact with the edge of the glass ribbon in the drawing chamber; An air bearing associated with the shaft allowing the shaft to be displaced in a direction transverse to the longitudinal axis of the shaft; And a seal assembly comprising the first seal plate secured to the shroud and the second seal plate connected to the shaft, wherein a gap is formed between the first seal plate and the second seal plate, the gap Gas is injected to maintain the air pressure in the gap at a second pressure P _g equal to or less than the first pressure P _s , the first seal plate comprising a slot, through which the A shaft extends into the drawing chamber, and the slot enables movement of the shaft across the longitudinal axis of the shaft.

C11. In connection with the drawing device according to C10, the first seal plate or the second seal plate consists of a layer of graphite or boron nitride.

C12. With regard to the drawing device according to C10 or C11, the coefficient of friction between the opposing faces of the first seal plate and the second seal plate is 0.4 or less.

C13. In connection with the drawing device according to C10-C12, the shaft is connected with a gas bearing.

C14. The glass ribbon drawing method comprises the steps of: drawing a glass ribbon out of a molded body, wherein the glass ribbon passes through a drawing chamber formed of shroud disposed relative to the glass ribbon, the shroud comprising a first seal plate and an air pressure in the drawing chamber. Is the first pressure P _s ); Contacting the glass ribbon with an edge roll assembly wherein the edge roll assembly extends through the passageway from the first seal plate through which the shaft can move in a direction transverse to the longitudinal axis of the shaft; A rotatable shaft comprising a second seal plate associated with the shaft such that the second seal plate rotates with the shaft; As the second seal plate rotates relative to the first seal plate such that the second pressure P _g of the air pressure in the first gap is equal to or less than the first pressure P _s , pressurized gas is released. And spraying a first gap between the first seal plate and the second seal plate, wherein contacting the glass ribbon with an edge roll assembly includes acting with the shaft to apply a pressing force to move the shaft laterally. Steps.

C14. With regard to the drawing method according to C15, the maximum frictional force to prevent shaft displacement is less than 2.3 kg.

C16. With regard to the drawing method according to C14 or C15, the contact surface exerts a substantial contact force on the glass ribbon.

C17. With regard to the drawing method according to C14-C16, the shaft displacement comprises supporting the shaft with a gas bearing.

C18. In connection with the drawing method according to C14-C17, the edge roll assembly is arranged such that the third seal plate is disposed facing the first seal plate such that the second seal plate rotates between the first seal plate and the third seal plate. It further includes.

C19. With regard to the drawing method according to C14-C18, the method of the invention further comprises injecting a gas into a second gap between the second seal plate and the third seal plate.

C20. With regard to the drawing method according to C14-C19, the coefficient of friction between the opposing faces of the first seal plate and the second seal plate is not more than 0.4.

It will be appreciated that the above described embodiments, particularly the "preferred" embodiments, have been described by way of example only so that the present invention may be clearly understood. It will be appreciated that various changes and modifications to the invention may be made without departing substantially from the scope of the invention. It will be appreciated that all such changes and modifications are possible within the scope of the invention and within the scope of the following claims.

Claims (10)

As drawing device of glass ribbon,
A molded body 12 for supplying the glass ribbon 20;
A shroud 22 forming a drawing chamber and disposed with respect to the glass ribbon;
Edge roll assembly; And
A second seal plate 66 associated with the shaft 44,
The shroud 22 includes a first seal plate 56, the air pressure of the drawing chamber is a first pressure P _s ,
The edge roll assembly is:
A rotatable shaft 44 extending through the shroud 22 into the drawing chamber; and
A contact surface 40 disposed on the shaft 44 in contact with the edge 34 of the glass ribbon in the drawing chamber,
A gap 74 is formed between the first seal plate and the second seal plate, and gas is injected into the gap so that the air pressure in the gap is equal to or less than the first pressure P _s . P _g ), the first seal plate 56 includes a slot 58, the shaft extending through the slot into the drawing chamber such that the shaft 44 is the length of the shaft 44. Drawing device of a glass ribbon, characterized in that it can move across the direction axis (86). The method according to claim 1,
The gas is injected through a passage (70) formed in the first seal plate (56) open at the surface of the first seal plate (56) facing the second seal plate (66). Drawing device of ribbon. The method according to claim 1,
Positioned such that the shaft 44 passes through the opening of the third seal plate 78 and the second seal plate 66 is disposed between the first seal plate 56 and the third seal plate 78. And a third seal plate (78). The method according to claim 3,
The third seal plate 78 includes a gas passage 84 open at one side of the third seal plate 78 facing the second seal plate 66, through which the gas passes through the gas passage. And a glass ribbon is drawn in the gap between the second seal plate and the third seal plate. The method according to claim 3,
And a spring member (88) positioned between the second seal plate (66) and the third seal plate (78). The method according to claim 1,
And the first seal plate (56) or the second seal plate (66) is made of a layer of graphite or boron nitride (71). The method according to claim 1,
And the shaft (44) is connected with an air bearing which causes the shaft (44) to displace in a direction transverse to the longitudinal axis of the shaft. As a drawing method of the glass ribbon,
Drawing the glass ribbon (20) from a molded body (12);
Contacting the glass ribbon 20 with an edge roll assembly;
As the second seal plate 66 rotates relative to the first seal plate 56 such that the second pressure P _g at the first gap is equal to or less than the first pressure P _s . Injecting pressurized gas into a first gap between the first seal plate 56 and the second seal plate 66,
The contacting of the glass ribbon 20 with the edge roll assembly may comprise interlocking a pressing force 54 with the shaft that displaces the shaft 44 in a direction transverse to the longitudinal axis of the shaft 44. Including,
The glass ribbon passes through a draw chamber formed of shroud 22 disposed relative to the glass ribbon 20, the shroud 22 including the first seal plate 56, and the air pressure in the draw chamber is Is the first pressure P _s ,
The edge roll assembly is:
A rotatable shaft (44) extending from said first seal plate to said drawing chamber through a passage (58) said shaft is movable in a direction transverse to said longitudinal axis of said shaft;
A second seal plate (66) connected with the shaft (44) such that the second seal plate (66) rotates with the shaft (44);
And a contact surface (40) disposed on said shaft (44) in contact with an edge of said glass ribbon (20). The method according to claim 8,
The contact surface (40) is a method of drawing a glass ribbon, characterized in that to apply a substantial contact force to the glass ribbon (20). The method according to claim 8,
The edge roll assembly is disposed so as to face the first seal plate 56 such that the second seal plate 66 rotates between the first seal plate 56 and the third seal plate 78. And a third seal plate (78).

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