JPS6235975B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device as defined in the generic form of claim 1 for bending a glass sheet heated to a softening temperature.

Devices for bending a glass sheet heated to a softening temperature are known from German Patent Nos. 1,679,961 and 2,331,584, in which a bending rod is used in a plane defined by the surface of the shape of the bend. However, each rod is configured to rotate around an axis connecting both ends of the rod, thereby deforming the plastic glass plate according to the shape of the rod. The bending force is obtained by pressing the glass plate against opposed molds or rollers having the same shape as the mold rod. A disadvantage of this device is that there are problems maintaining accurate curve formation lines. That is, when feeding a flat glass plate along a horizontal conveying plane onto a mold rod that is curved but pivoted into a horizontal conveying speed plane,
In the case of glass sheets that are asymmetrical with respect to the conveying direction axis, different lateral forces occur on both sides of the longitudinal axis. Therefore, the glass plate is likely to shift laterally, and as a result, the angle between the intended bending axis and the actual bending axis that coincides with the feeding direction may not be zero.

Another drawback is that when the curved rod is swiveled upwards, the glass pane is guided only by its center, which means that it can no longer maintain a stable position. Another problem that degrades optical quality, especially in the case of thin glass sheets, is the area of surface contact, where local variations in cooling of the glass sheet appear due to intense heat exchange, and when using a curved opposed roller. Another problem is the so-called opposed roller effect, which generates transverse waves in glass sheets that are particularly thin and have low bending resistance, making it difficult to manufacture optically superior curved glass sheets.

In the device of German Publication No. 2621902, a glass sheet runs over a mold rod which is curved in an upwardly convex manner, with the degree of curvature of the curve forming line gradually increasing in the passing direction. The shape of the heated and softened glass plate follows the curved shape of the rod under the action of gravity. A significant drawback of this device is again that the curve formation line is not precisely fixed. The more irregular the shape given to the glass plate, the more difficult it becomes to maintain the desired precise curvature. For example, in the case of a tapered glass plate, different gravitational effects are applied to the partial areas that are given different shapes on each side of the curvature forming axis, and the curvature does not proceed consistently, resulting in almost unsolvable difficulties. .

A device for bending glass panes heated to a softening temperature in this manner is also known from German Patent No. 2,532,318, in which the mold rod consists of a core and a rotatable driven sleeve, for example a sleeve.
To transport glass sheets that are still flat, the curved rod is swiveled into a horizontal position so that a horizontal transport plane is formed. When starting the bending process, the curved rod is pivoted downward. The actual bending process is carried out by raising the entire system together with the mold rod and pressing it against the opposing mold. The main advantage of this known device is the precise positioning of the glass pane, but the disadvantage is that the glass pane must remain stationary while the actual bending operation takes place, making continuous movement impossible. In addition, in this device, the glass plate, which is still flat, must be conveyed by passing over a curved rod that has been turned to a horizontal plane, which is different from other known devices in which the glass plate tends to shift laterally during this conveyance. Related problems arise that have already been mentioned.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an apparatus for bending a glass plate heated to the softening temperature in which the above-mentioned problems do not occur.

In particular, we propose an apparatus that can correctly guide a glass plate that is still flat, and can evenly bend even an extremely thin glass plate without deteriorating its optical properties.

This object is achieved in the present invention by the features described in claim 1.

Preferred embodiments are described in the following claims.

The advantages achieved with the invention are based on the following operational aspects.

The glass sheet, heated to a softening temperature from the furnace and ready for plastic deformation but still in flat shape, is conveyed by a plurality of linear conveyor rods to the actual deformation station. In this deformation section, a mold rod, which is curved once downward, is fixedly installed between the individual conveyor rods. When the transported glass sheet reaches the deformation station, first of all the pressing means, which can consist, for example, of a pressing roller with a pressure cylinder, are lowered from above onto the surface of the glass sheet. Since this pressure roller is located directly above a single straight conveyor rod, it is impossible for bending moments to occur which could cause transverse wave deformations in the delicate glass sheets.

The linear conveyor rod also descends in synchronization with this descent of the pressing means. This can be done, for example, by starting the lowering of the conveyor rod at the moment the pressure roller comes into contact with the surface of the glass sheet. The conveyor rod descends to a deforming operation position corresponding to the position of the fixed mold rod which is curved downward. As a result, the plastic glass plate is deformed into a desired curved shape.

During this series of operations, the glass plate is conveyed as it is, in which case any relative movement between the rod sleeve and the glass plate is avoided since the curved rod is oriented precisely downward. Therefore, the curvature of the mold rod must be adapted to the desired shape of the glass plate to be processed. However, this is an extremely preferable configuration in terms of the optical quality of the curved glass plate. That is, there is no relative movement that causes distortion, which may be slight but cannot be overlooked optically.

In order to facilitate the work of replacing the curved rod according to the desired curved shape of the glass plate, the mold rod is mounted on an independent machine frame that can be easily replaced from the side by pulling it out along the rail. be.

Generally, the pressure roller is allowed to rotate freely. That is, when it comes into contact with the glass plate, it is rotated by the glass plate. However, in the case of an extremely thin and delicate glass plate, it is preferable to drive the pressure roller in accordance with the feeding speed of the glass plate in order to avoid any relative movement.

If the bending process is performed without changing the feeding speed of the glass plate, the time it takes for the glass plate to pass through the original deformed part is extremely short, so the amount of heat dissipated is very small. The advantage is that the prestress introduction section on the downstream side can be entered at almost the same temperature as when leaving the furnace provided on the side.

Furthermore, since the pressure roller that descends from above onto the glass plate comes into contact with the glass plate only in a very limited area, there is very little heat exchange with the high temperature glass surface. This contributes to maintaining the glass pane at the required high temperature.

When the glass sheet curved by the curved rod is conveyed away from the deformation station, the straight conveyor rod in the deformation station is very quickly raised into the conveying position, for example under the action of a compressed air cylinder; The next glass plate can enter the deformation section.

The advantage of using a mostly fixed type of curved rod is that there is no need to adjust individual mold rods, but only to convert the mold rods as a whole in response to the change in curvature to be applied to the glass pane. Known devices in which the mold rods had to be rotated individually required cumbersome adjustments and were often not able to be adjusted with the required accuracy, resulting in wavy deformations in the curved glass sheets. Ta. This problem is solved by the simple construction of the present invention.

The feeding rate of the flat glass plate as it exits the furnace is higher than the rate at which it passes through the furnace, so that the glass plate passes through the deformation section at a relatively high speed, even if the number of curved rods used is relatively small. Preferably, the plasticized glass sheet is allowed little time to "sink" into the gap between the mold rods.

In order to produce high-quality curved prestressed glass sheets, it is necessary to provide a prestressing introduction section downstream of the deformation process that rapidly cools the curved glass sheet by applying a gas flow, generally an air flow. . A prestressing inlet is known from German Publication No. 2 213 670, which is designed to pass a glass plate between conveyor rods placed one above the other. However, this conveyor rod prevents the flow of the gas flow on both sides of the glass plate, especially the escape of the gas flow, so that the desired quenching effect cannot be obtained. Moreover, although this known device is able to generate the necessary stagnation pressure in the rod area, it does not take into account that the heat transfer is impeded by these same rods. Therefore,
Fairly high gas flow driving energies must be used to achieve the desired heat transfer. When such a prestress introduction part is used to treat a relatively thick glass plate, the above-mentioned drawbacks do not pose much of a problem, but in the case of a thin glass plate, for example, an automobile side window glass plate with a thickness of only 3 mm, Treatment is only possible by significantly increasing the airflow velocity. However, as the speed increases, the pressure generated on the surface of the glass plate increases by a factor of two, and especially in the case of thin glass plates, the surface deforms and the optical quality deteriorates beyond the permissible limit.

In order to avoid such problems, a nozzle rib is installed between the curved rods on the lower side of the glass plate in the prestress introducing section provided downstream of the deformation processing section, and the glass plate is placed so as to face the nozzle rib accurately. A nozzle rib shaped to match the curvature of the glass plate is installed above. A throttle is incorporated in the back area between the upper nozzle ribs to increase the pressure level above the glass plate without creating additional stagnation areas that adversely affect heat transfer. This throttle prevents the glass plate from lifting as a result of an increase in downward positive pressure and reduces the necessary pressing force on the glass plate.

By appropriately selecting the diameter and distribution of the holes in the upper and lower nozzle ribs, it is possible to ensure uniform heat conduction on both sides of the glass plate even if there are differences in the flow conditions of the gas flow.

As an alternative to this embodiment, a curved condensation rod may be integrated into the downward blowing system and configured to utilize the Coanda effect to guide the gas flow along the conveyor rod and impinge tangentially on the curved glass pane. good. With this configuration, the conveyor rod and mold rod, which were obstacles to the ventilation system in the conventional prestress introducing section, can be used to guide the gas flow, thereby improving the action of the gas flow so that a rapid cooling effect can be obtained. be able to.

The present invention will be described in detail below with reference to embodiments shown in the accompanying drawings.

As is clear from FIG. 1, a flat glass plate 1 heated to a softening temperature by a furnace (not shown) is
A linear conveyor rod 3, which constitutes a roller conveyor 2 as a whole, transports the material to the original deformation processing section 4. Straight conveyor rods 3 are also arranged in the deformation processing section 4. A curved mold rod 5 is interposed between two adjacent conveyor rods 3 (Fig. 3). As can be seen from the apex line 8 in FIG. 1, it is located below the linear conveyor rod 3.

When the glass plate 1 is completely conveyed to the deformation processing section 4, the pressing roller 6 descends to the upper surface of the glass plate 1. This pressure roller 6 is actuated by a pressure cylinder 6' which generates a precise pressure force.

The pressure roller 6 and the pressure cylinder 6' are mounted on a gallows-shaped machine frame 2 which is connected to the support structure of the conveyor rod 3 in the deformation section 4. Machine frame 2
The pressing roller 6 and the linear conveyor rod 3 in the deforming section 4 can be vertically lowered together.

When the freely rotatable pressure roller 6 aligned in the feeding direction of the glass sheet 1 comes into contact with the upper surface of the glass sheet 1 which has completely reached the deformation section 4, the upper contact plane 7 of the straight conveyor rod 3 forms a curved rod. The pressing roller 6 and the linear conveyor rod 3 in the deforming section 4 descend until they coincide with the apex line 8 of the deforming section 5. Since the pressure roller 6 is located directly above the linear conveyor rod 3, no bending moment is applied by the pressure roller 6.

During the above process, the glass plate 1 is directly fed in the direction of the arrow and passes through the deforming section 4, and during this conveyance, the press roller 6 and the mold rod 5 cooperate to give the glass plate a required curvature.

The curved rod 5 is fixed to a machine frame 20 which can be replaced by pulling it out to the side on a rail 21. Such replacement work becomes necessary, for example, when it is desired to manufacture glass plates with different curvatures. This is because the curvature of the mold rod, which is given a vertical downward curvature, must match the curvature that is desired to be given to the glass plate to be manufactured.

The conveyor rod 3 and the mold rod 5 have a known construction. That is, the core is surrounded by a rotatable driven outer cylinder. The sleeve may be, for example, a sleeve molded to the core, or a number of rings may be fitted around the core.

FIG. 3 schematically shows the drive of the curved rod 5 by an electric motor M via a chain K.

The curved glass plate 1 is a curved rod 5
Due to the rotation of the outer cylinder, it is carried away from the deformation processing section 4 and reaches the prestress introducing section, which will be described later. Next, the linear conveyor rod 3 which is being deformed is raised again to the conveying operation position by a compressed air cylinder (not shown), and the next glass plate 1 is ready to enter the deforming section 4.

FIG. 4 is a cross-sectional view of a prestress introduction section disposed downstream of the deformation processing section 4. As shown in FIG. The curved glass pane 1 is guided in the prestressing introduction section by a curved rod 5 which here acts as a conveying means. A nozzle rib 10 is disposed below a curved glass plate 16 in the gap between the curved rods 5.
is located. A similar upper nozzle rib 9 is disposed above the curved glass plate 16 passing through the prestress introduction part in the direction of the arrow so as to directly face the lower nozzle rib 10. The nozzle ribs 9 and 10 are configured to match the uneven shape of the glass plate, and send not only an airflow perpendicular to the glass plate but also an airflow in an oblique direction.

In order to increase the pressure level above the glass plate 16 without creating stagnation zones that adversely affect heat transfer, a throttle 11 is incorporated in the back area between the upper nozzle ribs 9. This throttle causes the glass plate 16 to increase due to the increased positive pressure below the glass plate 16.
This prevents the glass plate 16 from floating up, and thereby allows the glass plate 16 to be pressed against the curved rod 5 with a slight pressing force from above.

By appropriately selecting the diameter of the nozzle and the distribution of holes, the upper nozzle rib 9 is connected to the lower nozzle rib 10 so that even if the flow state on the upper side of the glass plate 16 is uneven, uniform heat conduction can be obtained as in the lower side. It can be synchronized with.

FIG. 5 shows a further embodiment of the prestress introduction, in which the curved rod 5 is integrated with the ventilation system below the glass plate 16. As schematically illustrated in FIG. 5, the Coanda effect is used to direct the gas flow along a curved rod 5 with a circular cross section, which curves as required to achieve favorable heat transfer. It acts tangentially on the glass plate 16. That is, the gas flow does not directly impinge on the surface of the gas plate, which is important for the optical properties of the curved glass plate 16.

Since in this embodiment the upper nozzle rib 9 is located directly above the center line of the curved rod 5, the force of the gas flow does not exert a bending moment on the curved glass plate.

In order to integrate the curved rod 5 with the nozzle range, for example, the mold rod may be surrounded on both sides by slit-shaped jets.

As an alternative to the embodiment described above, the rotatable outer cylinder of the mold rod 5 may be constituted by a ring 14, as shown in FIG. A curved annular groove 15 is formed between the rings 14, and air is ejected from an air supply nozzle 17 located below the mold rod 5, passing through all the annular grooves 15 of each mold rod 5 in the same direction. Alternatively, air is blown in different directions for each annular groove 15 of each mold rod 5. In the area of contact between the glass plate 16 and the mold rod 5, this air flow passes through the glass plate 16 at high speed to achieve the necessary heat transfer.

In order to deform the glass plates and introduce prestress, the feeding speed of the glass plates 1 and 16 when leaving the furnace is higher than the passing speed in the furnace.In particular, by passing through the deformation processing section 4 at high speed, the glass plates 1 and 16 are fed between mold rods 5 and conveyor rods. It is necessary to reduce the time margin for "sinking" in the gap between the glass plates and to prevent the formation of wavy distortions on the glass plate surface.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the deformed part showing the linear conveyor rod in its original conveying position;
Fig. 2 is a longitudinal cross-sectional view of the deformation processing section showing the linear conveyor rod lowered to the deformation processing position;
Fig. 3 is a cross-sectional view of the deformation processing section, Fig. 4 is a first embodiment of the prestress introducing section placed downstream of the deformation processing section, and Fig. 5 is a cross-sectional view of the prestress introduction section placed downstream of the deformation processing section. Embodiment 2 of the prestress introduction section, FIG. 6 is a perspective view showing a modification of the embodiment illustrated in FIG. 5. 1... Flat glass plate, 2... Machine frame, 3... Conveyor rod, 4... Deformed processing section, 5... Curved rod, 6... Press roller, 6'... Pressure cylinder, 7... Conveyor rod. Upper tangent surface, 8... Vertex line of curved rod, 9, 10, 12... Nozzle rib, 11... Throttle, 14... Ring, 1
5...Ring gap, 16...Curved glass plate.

Claims (1)

[Scope of Claims] 1 (a) A plurality of conveyor rods that collectively form a horizontal surface and transport flat glass plates; (b) A plurality of conveyor rods that are curved to match the shape of the glass plate after being curved and placed in a deformation processing section. (c) a pressing means for pressing the glass plate against the mold rods; (d) the conveyor rod and the mold rod are heated to a softening temperature comprising a core and a rotatable driven barrel; In a bending device for bending a glass plate, (e) the linear conveyor rod 3 in the deformation section 4 can move up and down between an upper conveyance position and a lower deformation work position; The fixed, curved mold rod 5 is positioned at a height corresponding to the deformation working position of the conveyor rod 3; 1. A glass plate bending processing device characterized by being pressed into contact with a glass plate. 2. The apparatus according to claim 1, wherein the pressing means is comprised of a pressure cylinder 6' and a pressing roller 6 arranged in a direction perpendicular to the glass plate feeding direction. 3. Device according to claim 2, characterized in that the pressure roller (6) is located above the linear conveyor rod (3). 4. The device according to claim 2 or 3, characterized in that the pressing force generated from the pressure cylinder 6 can be adjusted. 5. Claims 1 to 4, characterized in that the pressing means 6, 6' come into contact with the flat glass plate 1 earlier than the descent of the conveyor rod 3, and are lowered together with the conveyor rod 3 to the deformation working position. The device according to any one of the preceding paragraphs. 6. Device according to claim 5, characterized in that the pressing means 6, 6' are raised before the trailing edge of the glass plate 1 passes. 7. Claims 2 to 6, characterized in that the pressure cylinder 6' is supported together with the pressure roller 6 by a gallows-shaped machine frame 2 that is movable up and down.
The device according to any one of the preceding paragraphs. 8. The device according to any one of claims 2 to 7, characterized in that the pressure roller 6 is freely rotatable. 9. The apparatus according to any one of claims 2 to 7, wherein the press roller 6 is rotationally driven in accordance with the feeding speed of the glass plate 1. 10. The device according to any one of claims 1 to 9, characterized in that the upper tangent surface of the conveyor rod 3 coincides with the apex line 8 of the curved rod 5 in the deformation working position. . 11. The apparatus according to any one of claims 1 to 10, characterized in that the conveyor rods 3 and the mold rods 5 are arranged alternately in the deforming section 4. 12 A nozzle rib 10 formed to match the shape of the curved glass plate 16 is arranged between the curved rods 5 behind the deformable part 4 when viewed in the feeding direction, and a nozzle rib 10 formed to match the shape of the curved glass plate 16 is arranged from the nozzle rib to the curved glass plate 16. 12. Device according to claim 1, characterized in that the gas flow is applied in vertical and oblique directions. 13 The curved rod 5 is integrally assembled into the nozzle rib 12 behind the deformation processing section 4 as seen in the feed direction, and the curved glass plate 16 is attached from the nozzle rib 12 along the outer surface of the mold rod 5 using the Coanda effect. 12. Device according to claim 1, characterized in that it guides a gas flow. 14 The outer cylinder of the type rod 5 is composed of a plurality of rings 14 arranged back and forth in the axial direction, and the gas flow is made to flow through the gap 15 between the rings 14. The device according to scope 13. 15. Claims 12 to 14 are characterized in that another nozzle rib 9 configured to match the shape of the glass plate is disposed above the curved glass plate 16, facing the lower nozzle ribs 10, 12. The device according to any one of the preceding items. 16. The device according to claim 15, characterized in that a throttle means (11) is provided between nozzle ribs provided above the curved glass plate (16). 17 Claims 1 to 16 characterized in that the feeding speed of the glass plate 1 when leaving the furnace and when passing through the deformation processing section is higher than the feeding speed when passing through the furnace. The device according to any one of the above.