JP7727906B2 - Glass plate manufacturing method and manufacturing device - Google Patents

Description

The present invention relates to a technology for manufacturing glass sheets, and more specifically to a technology for performing a first cut to cut a glass sheet from a glass ribbon that is being transported while being formed, and a second cut to cut the glass ribbon when the first cut is not being performed.

In the field of glass sheet manufacturing, it is well known to perform a first cutting process in which a glass ribbon that is being formed in a forming zone and moving continuously downward is cut widthwise at predetermined lengths to sequentially cut out glass sheets. In this case, since the melting furnaces and other equipment in glass sheet manufacturing facilities are typically operated continuously, the glass ribbon generally continues to be formed even if the equipment used to perform the first cutting process is unavailable due to maintenance or other reasons. Therefore, even if the first cutting process is not performed, it is necessary to cut and recover the glass ribbon that continues to be formed.

To meet such demands, for example, Patent Document 1 discloses that when the first cutting step is not performed, a second cutting step is performed in which the glass ribbon is cut using equipment with a different configuration from the equipment used in the first cutting step. The equipment used in this second cutting step includes a holding member that holds the glass ribbon, a pressing member that applies stress to the glass ribbon while it is held by the holding member, and a scribing member that carves a scribing line in the stressed portion of the glass ribbon.

China Utility Model Publication No. 205493369

In the above-described glass sheet manufacturing method, for example, if a cutting defect occurs when cutting the glass ribbon in the first cutting process, the crack may propagate in the conveying direction, causing the glass ribbon to break. The glass ribbon may also be scratched by the rollers conveying the glass ribbon, causing the glass ribbon to break. This type of breakage can result in the glass ribbon being completely broken and disappearing as it is being formed and conveyed. If the glass ribbon breaks, the first cutting process is interrupted, making it possible to start the second cutting process. If glass ribbon forming resumes after the glass ribbon breaks, the second cutting process is started. Conventionally, switching from the first cutting process to the second cutting process like this has been performed by an operator. This has made it difficult to perform a smooth switchover.

In light of the above, the present invention aims to smoothly switch from the first cutting process to the second cutting process.

The first aspect of the present invention, which was devised to solve the above problem, is a method for manufacturing a glass sheet, comprising: a first cutting step in which a glass ribbon being formed and transported is cut into glass sheets by a first cutting device; and a second cutting step in which the glass ribbon is cut by a second cutting device when the first cutting device is not in operation. The method is characterized by including a first detection step in which the presence or absence of a glass ribbon is detected by a sensor, and a switching step in which the first cutting step is switched to the second cutting step based on the detection result of the first detection step.

With this configuration, the switching process for switching from the first cutting process to the second cutting process is performed based on the detection results of a sensor that detects the presence or absence of a glass ribbon, allowing for smooth switching. Furthermore, by detecting the presence or absence of a glass ribbon using a sensor, it is possible to accurately determine, for example, when glass ribbon formation should resume, and start the second cutting process at the appropriate time.

In this configuration, the sensors may be installed at multiple locations across the width of the glass ribbon.

In this way, multiple sensors can be used to detect the presence or absence of the glass ribbon at multiple locations across the width, allowing for precise understanding of the shape of the glass ribbon at the time of breakage and the forming state of the glass ribbon when forming resumes after breakage.

In the above configuration, the sensors may be installed corresponding to at least both widthwise ends and a widthwise intermediate portion of the glass ribbon, and the detection results in the first detection process may be capable of distinguishing between a first state in which one of the widthwise end ends of the glass ribbon is being shaped while being conveyed, a second state in which one of the widthwise end ends and the widthwise intermediate portion of the glass ribbon are being shaped while being conveyed, a third state in which both widthwise end ends of the glass ribbon are being shaped while being conveyed, and a fourth state in which the entire widthwise portion of the glass ribbon is being shaped while being conveyed.

In this way, the glass ribbon forming and conveying processes when forming is resumed after breakage can be distinguished and understood according to the four states listed above, and the switching process and second cutting process can be carried out appropriately in accordance with the four states.

In the above configuration, in the first detection process, the sensor may detect the presence or absence of the glass ribbon upstream of the first cutting device and the second cutting device in the conveying direction.

In this way, the sensors can be used to confirm that glass fragments or other debris will fall due to breakage, and appropriate measures can be taken for the first and second cutting devices. Furthermore, the forming state of the glass ribbon when forming resumes after breakage can be confirmed, and the switching process and second cutting process can be carried out appropriately.

In this configuration, the switching process may include causing components of the second cutting device to advance from the evacuation area to the cutting area based on the detection results of the first detection process.

Here, the above-mentioned "cutting area" refers to the area where the second cutting device performs the cutting process of the glass ribbon. Furthermore, the above-mentioned "retreat area" refers to the area where the second cutting device retreats from the cutting area (for example, an area 500 mm to 2000 mm away from the glass ribbon transport path). Furthermore, the above-mentioned "components of the second cutting device" may refer to all or some of the components of the second cutting device.

In this way, after the glass ribbon breaks, it is possible to advance the components of the second cutting device from the evacuation area to the cutting area after confirming that glass fragments and the like have stopped falling into the cutting area. This makes it possible to avoid problems such as glass fragments and the like colliding with the components of the second cutting device when the second cutting device starts cutting the glass ribbon. Therefore, it is preferable that the evacuation area is an area where the above-mentioned glass fragments and the like will not fall. Furthermore, with this configuration, it is possible to appropriately advance the components of the second cutting device after confirming the forming state of the glass ribbon when forming is resumed after breakage.

In this configuration, the component of the second cutting device may be a part of all the components of the second cutting device and may be the component that advances earliest among all the components when the cutting process by the second cutting device begins.

In this way, by protecting the component that advances first from falling glass fragments, etc., it is possible to reliably protect other components that advance later. Furthermore, with this configuration, the forming state of the glass ribbon when forming resumes after breakage can be confirmed, and then the component that advances first can be operated appropriately.

In this configuration, the sensors are installed corresponding to at least both widthwise ends of the glass ribbon, and the component that advances earliest is one or both of the holding members used to hold both widthwise ends of the glass ribbon when cutting in the second cutting process, and the holding member corresponding to the widthwise end of the glass ribbon that is detected by the sensor to be present may be advanced, and the holding member corresponding to the widthwise end of the glass ribbon that is detected by the sensor to be absent may not be advanced.

In this manner, sensors are installed corresponding to at least both widthwise ends of the glass ribbon, so that one sensor detects the presence or absence of one widthwise end of the glass ribbon, and the other sensor detects the presence or absence of the other widthwise end of the glass ribbon. Furthermore, at the location corresponding to the widthwise end of the glass ribbon where the presence is detected, glass fragments or the like do not fall due to breakage, and therefore, even if the holding member corresponding to that widthwise end is advanced, problems such as glass fragments or the like colliding with the holding member do not occur. On the other hand, at the location corresponding to the widthwise end of the glass ribbon where the absence is detected, glass fragments or the like do fall due to breakage, so by not advancing the holding member corresponding to that widthwise end, problems such as glass fragments or the like colliding with the holding member can be avoided. Furthermore, with this configuration, the widthwise end of the glass ribbon where the presence is detected continues to be shaped and transported, so that the widthwise end needs to be cut. Therefore, by advancing the holding member corresponding to that widthwise end, the widthwise end can be cut to the appropriate length. On the other hand, widthwise ends of the glass ribbon that are detected as being absent can be left as they are until they are subsequently detected as being formed, so there is no need to advance the holding members corresponding to those widthwise ends.

The above-described configuration may further include a second detection process for detecting the presence or absence of a glass ribbon using sensors installed corresponding to at least both widthwise ends of the glass ribbon at positions downstream in the conveying direction from the sensors used in the first detection process, and the glass ribbon may be cut using components of the second cutting device advanced in the switching process based on the detection results of these sensors.

In this way, the glass ribbon cutting process using the components of the second cutting device (including the holding member described above) can be performed accurately by incorporating the detection results from the second detection process in addition to the detection results from the first detection process described above.

In this configuration, the components of the second cutting device may include a cutting blade used to cut the glass ribbon, and the cutting blade may be pressed against the glass ribbon based on the detection results of the second detection process.

In this way, the glass ribbon cutting process can be performed more accurately using the cutting blade and the above-mentioned holding member, etc.

In this configuration, the components of the second cutting device may include a pressing member that applies stress to the glass ribbon, and the pressing member may be caused to apply stress to the glass ribbon based on the detection results in the second detection process.

In this way, the glass ribbon cutting process can be performed even more accurately using the cutting blade, pressing member, and the above-mentioned holding member, etc.

The second aspect of the present invention, which was devised to solve the above problem, is a glass sheet manufacturing apparatus comprising a first cutting device that cuts a glass ribbon being transported while being formed to cut out a glass sheet, and a second cutting device that cuts the glass ribbon when the first cutting device is not in operation, characterized in that the apparatus is equipped with a sensor that detects the presence or absence of a glass ribbon, and is configured to perform a switching process to switch operation of the first cutting device to operation of the second cutting device based on the detection result of the sensor.

This allows for the same effects and advantages to be achieved as with the previously described manufacturing method, which has substantially the same configuration as this manufacturing apparatus.

This invention allows for smooth switching from the first cutting process to the second cutting process.

1 is a side view showing an overall configuration of a glass sheet manufacturing apparatus according to an embodiment of the present invention. 1 is a schematic front view showing a main part of a glass sheet manufacturing apparatus according to an embodiment of the present invention. FIG. 3 is a schematic side view illustrating the operation of a first cutting device in the glass plate manufacturing apparatus according to the embodiment of the present invention. FIG. 3 is an enlarged schematic plan view showing a second cutting device in the glass plate manufacturing apparatus according to the embodiment of the present invention. FIG. 3 is an enlarged schematic plan view showing a second cutting device in the glass plate manufacturing apparatus according to the embodiment of the present invention. FIG. 3 is an enlarged side view showing a second cutting device in the glass plate manufacturing apparatus according to the embodiment of the present invention. FIG. 4 is an enlarged schematic side view showing the operation of a second cutting device in the glass plate manufacturing apparatus according to the embodiment of the present invention. FIG. 2 is a schematic front view of a main part illustrating an aspect when a glass ribbon is cut using a second cutting device in the glass sheet manufacturing apparatus according to the embodiment of the present invention. FIG. 2 is a schematic front view of a main part illustrating an aspect when a glass ribbon is cut using a second cutting device in the glass sheet manufacturing apparatus according to the embodiment of the present invention. 10( a ), ( b ), and ( c ) are schematic front views each showing an aspect of cutting a glass ribbon using the glass sheet manufacturing apparatus according to the embodiment of the present invention. 11( a ), ( b ), and ( c ) are schematic front views each showing an aspect of cutting a glass ribbon using the glass sheet manufacturing apparatus according to the embodiment of the present invention. 12( a ) and 12 ( b ) are schematic front views each showing an aspect of cutting a glass ribbon using the glass sheet manufacturing apparatus according to the embodiment of the present invention. 13( a ) and 13 ( b ) are schematic front views each showing an aspect of cutting a glass ribbon using the glass sheet manufacturing apparatus according to the embodiment of the present invention.

One embodiment of the present invention will be described below with reference to the accompanying drawings.

Figure 1 is a side view showing the overall configuration of a glass sheet manufacturing apparatus according to this embodiment. As shown in the figure, the glass sheet manufacturing apparatus mainly comprises a glass ribbon G processing device 1, a first cutting device 2, and a second cutting device 3. In the following description, the second main surface Gb side of the glass ribbon G (the side indicated by the arrow X1 in Figure 1) is referred to as the "front side," and the first main surface Ga side (the side indicated by the arrow Y1 in Figure 1) is referred to as the "rear side." In addition, in this embodiment, the downstream side of the conveying direction of the glass ribbon G is referred to as the "downward side (preferably vertically downward)," and the upstream side is referred to as the "upward side (preferably vertically upward)."

The processing device 1 includes a forming zone 11 for continuously forming the glass ribbon G, a heat treatment zone 12 for heat treating (slowly cooling) the glass ribbon G, a cooling zone 13 for cooling the glass ribbon G to near room temperature, and a conveying device 14 consisting of roller pairs R arranged in multiple vertical stages in each of the forming zone 11, heat treatment zone 12, and cooling zone 13.

The forming zone 11 and heat treatment zone 12 are constructed by furnaces with walls surrounding the transport path of the glass ribbon G, and heating devices such as heaters for adjusting the temperature of the glass ribbon G are arranged at appropriate locations within the furnace. On the other hand, the cooling zone 13 is not surrounded by walls around the transport path of the glass ribbon G, and is open to the ambient atmosphere at room temperature, and no heating devices such as heaters are arranged therein.

The internal space of the forming zone 11 is equipped with a forming body 15 that forms a glass ribbon G from molten glass Gm using the overflow downdraw method. The molten glass Gm supplied to the forming body 15 overflows from a groove (not shown) formed in the top 15a of the forming body 15. This overflowing molten glass Gm flows down both side surfaces 15b, which have a wedge-shaped cross section, of the forming body 15 and joins at the bottom end. This allows a plate-shaped glass ribbon G to be continuously formed. This continuously formed glass ribbon G is sent downward in a vertical position (preferably a vertical position).

The internal space of the heat treatment zone 12 has a predetermined temperature gradient downward. The glass ribbon G, which is in a vertical position, is heat-treated (slowly cooled) so that its temperature decreases as it moves downward through the internal space of the heat treatment zone 12. This heat treatment reduces internal strain in the glass ribbon G. The temperature gradient in the internal space of the heat treatment zone 12 is adjusted, for example, by a heating device installed on the inner wall surface of the heat treatment zone 12.

The multiple roller pairs R that make up the conveying device 14 clamp both widthwise ends of the glass ribbon G in a vertical position from both the front and back. The uppermost roller pair R arranged in the forming zone 11 is a cooling roller. Note that, in the internal space of the heat treatment zone 12, the multiple roller pairs R may include ones that do not clamp the widthwise ends of the glass ribbon G. In other words, the distance between the opposing roller pairs R may be greater than the thickness of both widthwise ends of the glass ribbon G, allowing the glass ribbon G to pass between the roller pairs R.

In this embodiment, both widthwise ends of the glass ribbon G produced by the processing device 1 have portions (hereinafter also referred to as "ear portions") that are thicker than the widthwise center portion due to factors such as shrinkage during the molding process.

The first cutting device 2 is configured to sequentially cut glass sheets from the glass ribbon G by cutting the glass ribbon G in a vertical position at predetermined lengths in the width direction below the processing device 1. The glass sheets become raw glass sheets (mother glass sheets) from which one or more product glass sheets are obtained in a later process by removing the edge portions. Here, the width direction is a direction perpendicular to the longitudinal direction (conveyance direction) of the glass ribbon G, and in this embodiment, it essentially coincides with the horizontal direction. In the following description, when the glass ribbon G is viewed from the rear as shown in Figure 2, the side indicated by arrow X2 in the figure is the left side in the width direction, and the side indicated by arrow Y2 in the figure is the right side in the width direction.

As shown in Figures 1 and 2, the first cutting device 2 includes a bending and splitting device 22. This bending and splitting device 22 is an apparatus that bends and splits the glass ribbon G along a scribe line S at a bending and splitting position P2 located below the scribe line formation position P1 to cut out a glass sheet. In this embodiment, the bending and splitting device 22 includes a bending and splitting member 23 that abuts the area where the scribe line S is formed from the second main surface Gb side, and a gripping mechanism 24 that grips the lower area of the glass ribbon G below the bending and splitting position P2.

The splitting member 23 is composed of a plate-like body (surface plate) having a contact surface (arc-shaped in side view) that contacts the entire width or part of the glass ribbon G. The contact surface of the splitting member 23 may be a curved surface that is curved in the width direction in plan view.

The gripping mechanism 24 includes chucks 25 arranged at multiple locations in the vertical direction at both widthwise ends of the glass ribbon G, and arms 26 (see Figure 2) that hold the multiple chucks 25 at both widthwise ends. Note that the chucks 25 may be modified to hold the glass ribbon G in other ways, such as by negative pressure suction.

A scribe line forming device 27 is provided above the first cutting device 2. This scribe line forming device 27 is a device that forms a scribe line S on the first main surface Ga of the glass ribbon G in a vertical position that has been lowered from the processing device 1 at the scribe line forming position P1. In this embodiment, the scribe line forming device 27 includes a wheel cutter 28 that forms a scribe line S on the first main surface Ga of the glass ribbon G along its width direction, and a support member 29 (e.g., a support bar or support roller) that supports the second main surface Gb of the glass ribbon G (the surface opposite the first main surface Ga) at a position corresponding to the wheel cutter 28. The scribe line S may also be formed by laser irradiation, etc.

As shown in FIG. 3, the first cutting device 2 and the scribe line forming device 27 are configured to move between a cutting area E1 (hereinafter referred to as the first cutting area E1) including the conveying path GS of the glass ribbon G and an evacuation area F1 (hereinafter referred to as the first evacuation area F1) spaced apart from the conveying path GS of the glass ribbon G on both the front and rear sides. Here, the first evacuation area F1 is spaced apart from the conveying path GS of the glass ribbon G on both the front and rear sides by a predetermined distance La. This predetermined distance La is, for example, 200 to 1000 mm, and preferably 300 to 600 mm. In this embodiment, the first cutting device 2 is configured so that both the splitting member 23 and the gripping mechanism 24 move only from the first cutting area E1 to the forward first evacuation area F1. Furthermore, the scribe line forming device 27 is configured so that the support member 29 moves from the first cutting area E1 to the front first evacuation area F1, and the wheel cutter 28 moves from the first cutting area E1 to the rear first evacuation area F1.

Furthermore, a first sensor 30 that detects the presence (state) of the glass ribbon G is disposed at a fixed position above the first cutting device 2 (see Figures 1 and 2). In the illustrated example, the first sensor 30 is disposed behind the conveying path GS of the glass ribbon G, but it may also be disposed in front of the conveying path GS. Furthermore, the first sensor 30 is disposed above the scribe line forming device 27, but it may also be disposed between the first cutting device 2 and the scribe line forming device 27.

In this case, as shown in FIG. 2, multiple first sensors 30 are installed corresponding to multiple locations in the width direction of the glass ribbon G. In this embodiment, a total of three first sensors 30 are installed at locations corresponding to both width ends of the glass ribbon G and at a location corresponding to the width center. These first sensors 30 are fixed to an installation member not shown in the figure so as to be aligned in a straight line in the width direction. As the first sensors 30, laser sensors, ultrasonic sensors, thermo sensors, etc. are used. The first sensors 30 constantly detect the presence or absence of the glass ribbon G.

As shown in Figures 1 and 2, the second cutting device 3 is disposed below the first cutting device 2 and cuts the glass ribbon G being formed in the forming zone 11 and transported downward when the first cutting device 2 is not in operation (for example, during maintenance or when forming of the glass ribbon G is resumed).

The second cutting device 3 has a main body frame 31 consisting of a framework disposed behind the glass ribbon G. Attached to the front end of the main body frame 31, in order from above, are a pair of holding devices 32, a pair of cutting devices 33, and a stress applying device 34.

The pair of holding devices 32 each include holding members 36 arranged corresponding to both widthwise ends of the glass ribbon G, and each of the pair of holding members 36 is rotatable around a rotation axis 37 (see Figures 4 and 5). Therefore, each of the pair of holding members 36 can be changed between a state in which it extends in the front-to-rear direction away from both widthwise ends of the glass ribbon G as shown in Figure 4 (the state shown by solid lines in Figure 6), and a state in which it extends in the left-to-right direction to hold the second main surface Gb of the glass ribbon G as shown in Figure 5 (the state shown by dashed dotted lines in Figure 6).

Furthermore, as shown in FIG. 6, each of the pair of holding members 36 is connected via a rotation shaft 37 to the front end of a slide arm 36a that is elongated in the front-rear direction. The pair of slide arms 36a are held slidably in the front-rear direction on guide members 36b, each fixed to the upper end of the main frame 31. As shown in FIG. 7, each of the pair of holding members 36 is configured to move between a cutting area E2 (hereinafter referred to as the second cutting area E2) that includes the conveying path GS of the glass ribbon G and an evacuation area F2 (hereinafter referred to as the second evacuation area F2) that is spaced rearward from the conveying path GS of the glass ribbon G. Here, the second evacuation area F2 is spaced rearward from the conveying path GS of the glass ribbon G by a predetermined distance Lb. This predetermined distance Lb is, for example, 500 to 2000 mm, preferably 700 to 1500 mm, and is longer than the above-mentioned predetermined distance La. These holding members 36 are held at the same height and can each move independently. In this case, the advancement of each holding member 36 from the second evacuation area F2 to the second cutting area E2 is performed based on the detection result of the first sensor 30. The evacuation of each holding member 36 from the second cutting area E2 to the second evacuation area F2 is also performed based on the detection result of the first sensor 30. In this embodiment, the forward and backward movement of each holding member 36 (each slide arm) is performed by the operation of a driving means (e.g., an air cylinder or ball screw mechanism) not shown, and the operation of the driving means is controlled based on a signal from the first sensor 30.

The pair of cutting devices 33 includes rotary blades 38 arranged corresponding to both widthwise ends of the glass ribbon G, and each of the pair of rotary blades 38 is movable in the front-to-rear direction (a direction inclining upward toward the front) (see Figures 2 and 6). Furthermore, each of the pair of rotary blades 38 can be moved between a state in which it is retracted rearward from the glass ribbon G as shown in Figure 4 (a state shown by solid lines in Figure 6) and a state in which it presses against both widthwise ends of the glass ribbon G as shown in Figure 5 (a state shown by dashed lines in Figure 6). Each of the pair of rotary blades 38 can also be moved left and right. The pair of rotary blades 38 are held at the same height and can move and operate independently. When each rotary blade 38 is pressed against the glass ribbon G, it can perform the processes of inscribing a scribe line at the widthwise end of the glass ribbon G and cutting the widthwise end of the glass ribbon G.

The stress applying device 34 has a pressing member 41 attached to the tip of a pair of swinging arms 40 that can swing around a support shaft 39 (see Figures 2 and 6). The pressing member 41 is a roller-shaped member that extends in the width direction and is longer than the width direction length of the glass ribbon G. Furthermore, the pressing member 41 can be changed between a state in which it is retracted rearward from the glass ribbon G as shown in Figure 4 (the state shown by the solid line in Figure 6) and a state in which it presses the glass ribbon G as shown in Figure 5 (the state shown by the dashed line in Figure 6). When the pressing member 41 is pressing the glass ribbon G, a bending stress is applied to the glass ribbon G (details will be described later).

Furthermore, as shown in FIG. 6, the second cutting device 3 is equipped with a second sensor 35 that detects the presence or absence of the glass ribbon G. In the illustrated example, the second sensor 35 is fixed to the main frame 31 and positioned rearward of the conveying path of the glass ribbon G. The second sensor 35 is also positioned at a height midway between the support shaft 39 at the upper end of the stress applying device 34 and the pressing member 41 at the lower end. In this case, as shown in FIG. 2, multiple second sensors 35 are installed corresponding to multiple locations in the width direction of the glass ribbon G. In this embodiment, a total of three second sensors 35 are installed at locations corresponding to both widthwise ends and the widthwise center of the glass ribbon G. These second sensors 35 are fixed to the front end of the main frame 31 in a straight line along the width direction and held in a fixed position. A laser sensor, ultrasonic sensor, or thermosensor may be used as the second sensor 35. The second sensor 35 constantly detects the presence or absence of the glass ribbon G.

This manufacturing apparatus is configured to perform a switching process to switch operation from the first cutting device 2 to the second cutting device 3. In this embodiment, the switching process corresponds to advancing the holding member 36, which is extended in the front-to-rear direction, from the second evacuation area F2 to the second cutting area E2. After the switching process is performed, the second cutting device 3 cuts the glass ribbon G while the holding member 36 remains in the second cutting area E2.

Here, we will explain the basic cutting process (hereinafter referred to as the first process) performed by the second cutting device 3. When performing the first process, first, while the glass ribbon G is continuously conveyed downward as shown by the solid lines in FIG. 6 , the pair of holding members 36 rotate around the rotation shaft 37 from a state in which they are extended in the front-to-rear direction. As a result, the pair of holding members 36 extend in the left-to-right direction as shown by the dashed-dotted lines in the same figure, enabling them to hold the second main surface Gb of the glass ribbon G. Next, under this state, the pressing member 41 swings forward. As a result, the pressing member 41 presses the glass ribbon G as shown by the dashed-dotted lines in the same figure, applying bending stress to the glass ribbon G around the region Gx to be cut. At this time, the pair of holding members 36 hold the second main surface Gb of the glass ribbon G above the region Gx to be cut, preventing the glass ribbon G from displacing forward. Furthermore, under this state, the pair of rotary blades 38 move forward. As a result, the pair of rotary blades 38 press the first main surface Ga of the glass ribbon G as shown by the dashed dotted lines in the figure, and carve a scribe line (initial crack) into the glass ribbon G. The pair of rotary blades 38 simultaneously carve the initial cracks at both widthwise ends of the glass ribbon G. Note that, when sufficient bending stress is applied to the periphery of the region Gx to be cut of the glass ribbon G over the entire widthwise length, one of the rotary blades 38 may carve the initial crack only at one widthwise end of the glass ribbon G. The carved position of the initial crack may be a position that includes or does not include the ear portion of the glass ribbon G. The initial crack then propagates along the widthwise direction of the glass ribbon G, thereby cutting the glass ribbon G. The cut glass becomes unwanted glass Gy and falls downward, and is collected in the collection area 42. Thereafter, the holding member 36 again extends in the front-rear direction to prepare for the subsequent cutting process. In addition, an opening 44 is formed in the floor wall 43 on which the second cutting device 3 is mounted to allow the cut glass to fall into the recovery area 42.

This first process is repeated while the second cutting device 3 is operating and there is no damage to the glass ribbon G. When the second cutting device 3 is not operating, the holding member 36 is retracted to the second retraction area F2 while extended in the front-to-rear direction.

In addition to the first process described above, the second cutting device 3 can also perform the second process described below. The second process is performed, for example, when only one widthwise end of the glass ribbon G is formed when forming resumes after breakage. When performing the second process, as shown in FIG. 8 , first, when only one widthwise end (the left end in the illustrated example) G1 of the glass ribbon G is transported to the second cutting area E2, only the holding member 36 corresponding to that widthwise end G1 rotates from its longitudinally extended state to its laterally extended state. At this time, the holding member 36 corresponding to the other widthwise end (the right end in the illustrated example) of the glass ribbon G does not operate. Next, the rotary blade 38 corresponding to the widthwise end G1 of the glass ribbon G presses against the widthwise end G1 and moves laterally. As a result, the widthwise end G1 is cut along the line (straight line) indicated by the symbol L1 in the figure. At this time, the rotary blade 38 corresponding to the other widthwise end (the right end in the illustrated example) of the glass ribbon G does not operate. Although the figure illustrates an example of cutting only the right end G1 of the glass ribbon G in the width direction, cutting only the left end G of the glass ribbon G in the width direction can also be performed in the same way. When performing this second process, no bending stress is applied to the glass ribbon G by the pressing member 41.

Furthermore, in addition to the first and second processes described above, the second cutting device 3 can also perform the third process described below. The third process is a cutting process performed, for example, when forming resumes after breakage and only both widthwise ends of the glass ribbon G are formed, without forming the central portion of the glass ribbon G in the widthwise direction. When performing the third process, first, as shown in FIG. 9 , when only both widthwise ends G1, G2 of the glass ribbon G are transported to the second cutting area E2, the pair of holding members 36 rotate from their respective longitudinally extended positions to their laterally extended positions. Next, the pair of rotary blades 38 press both widthwise ends G1, G2 and move laterally. As a result, both widthwise ends G1, G2 are cut along the lines (straight lines) indicated by the symbols L1 and L2 in the figure. When performing this third process, the pressing member 41 does not apply bending stress to the glass ribbon G.

In this embodiment, the rotation of each holding member 36 is performed based on the detection results of the second sensor 35. More specifically, the rotation of each holding member 36 is performed by the operation of a drive means (e.g., a motor, etc.) not shown, and the operation of this drive means is controlled based on a signal from the second sensor 35. Furthermore, the forward/backward and left/right movement of each rotary blade 38 is also performed based on the detection results of the second sensor 35. More specifically, the forward/backward and left/right movement of each rotary blade 38 is performed by the operation of a drive means (e.g., an air cylinder or a ball screw mechanism, etc.) not shown, and the operation of this drive means is controlled based on a signal from the second sensor 35. Furthermore, the movement of the pressing member 41 is also performed based on the detection results of the second sensor 35. More specifically, the movement of the pressing member 41 is performed by the operation of a drive means (e.g., a motor, etc.) not shown, and the operation of this drive means is also controlled based on a signal from the second sensor 35.

Next, we will explain a method for manufacturing glass sheets using a glass sheet manufacturing apparatus with the above-described configuration.

The glass plate manufacturing method according to this embodiment includes a forming process, a transporting process, a first cutting process, a first detection process, a second cutting process, a second detection process, and a switching process.

The forming process is the process of forming glass ribbon G in the forming zone 11.

The conveying process is a process in which the formed glass ribbon G is conveyed by the roller pair R of the conveying device 14. The conveying process also includes a heat treatment process and a cooling process.

The heat treatment process is a process in which heat treatment is performed on the glass ribbon G while transporting the glass ribbon G that has undergone the forming process in the heat treatment zone 12.

The cooling process involves cooling the glass ribbon G that has undergone the heat treatment process while transporting it in the cooling zone 13.

The first cutting process is a process in which the glass ribbon G that has undergone the cooling process is conveyed and cut in the width direction by the first cutting device 2 to obtain glass sheets.

1 and 2 , in the first cutting step, the wheel cutter 28 and support member 29 first move to follow the glass ribbon G, which is continuously moving downward, and form a scribe line S across the entire width or a portion of the width of the glass ribbon G. In this embodiment, the scribe line S is also formed on the relatively thick edge portions. Next, after the glass ribbon G is gripped by the multiple chucks 25, the arm 26 moves the multiple chucks 25 to follow the glass ribbon G. At this time, the bending member 23 also moves to follow the glass ribbon G. While these movements are taking place, the arm 26 performs an operation (operation in the direction B shown in FIG. 1 ) to bend the glass ribbon G with the bending member 23 as a fulcrum. This applies bending stress to the scribe line S and its vicinity, and the glass ribbon G is bent and split in the width direction along the scribe line S. As a result of this bending and cutting, a glass plate is cut out from the glass ribbon G.

The first detection process is a process in which the presence or absence of glass ribbon G is detected using three first sensors 30.

The second cutting process is a process in which the glass ribbon G is cut using the second cutting device 3 when the first cutting device 2 is not in operation.

The second detection process is a process in which the presence or absence of glass ribbon G is detected using three second sensors 35.

The switching process is a process for switching from the first cutting process to the second cutting process based on the detection results of the first detection process. This switching process is carried out between the interruption of the first cutting process and the start of the second cutting process.

More specifically, while the first cutting step is being performed, i.e., while the first cutting device 2 is operating, the components of the second cutting device 3, namely the holding member 36, rotary blade 38, and pressing member 41, remain in the second retraction area F2 shown in Figure 7. On the other hand, while the second cutting step is being performed, i.e., while the second cutting device 3 is operating, the holding member 36 remains in the second cutting area E2 shown in Figure 7.

When the first detection process detects that the glass ribbon G is missing due to breakage during the first cutting process, the first cutting device 2 retreats from the first cutting area E1 to the first evacuation area F1. Then, a switching process is performed based on the detection results of the subsequent first detection process. Specifically, in the switching process, the holding member 36, which is extended in the front-to-rear direction, is advanced from the second evacuation area F2 to the second cutting area E2. Then, after this switching process, the second cutting process is performed. Therefore, the first cutting process is interrupted due to breakage, and then the holding member 36 advances, after which the second cutting process is performed. In this embodiment, the switching process is performed smoothly through automation, with reduced or no operator intervention required.

If the glass ribbon G breaks, glass fragments and the like will fall into the second cutting area E2, but the holding member 36 remains in the second evacuation area F2. The rotary blade 38 and pressing member 41 also remain in the second evacuation area F2. The holding member 36 advances from the second evacuation area F2 to the second cutting area E2 earlier than the rotary blade 38 and pressing member 41. In other words, of all the components of the second cutting device 3, the holding member 36 advances from the second evacuation area F2 to the second cutting area E2 earlier than the rotary blade 38 and pressing member 41.

Next, the process from when the glass ribbon G breaks during the first cutting process to when the glass ribbon G is cut in the second cutting process will be described with reference to Figures 10 to 13. In these figures, the three circles arranged above the first cutting device 2 represent the detection areas 30a of the three first sensors 30, and the three circles arranged in the vertically intermediate position of the second cutting device 3 represent the detection areas 35a of the three second sensors 35. In the following description, the presence of the glass ribbon G detected by the first and second sensors 30 and 35 will be described as "ON," and the absence of the glass ribbon G will be described as "OFF."

Figure 10 illustrates a first example of the above process. This first example illustrates a process in which, as shown in the figure, forming is resumed after the glass ribbon G breaks during the first cutting process, so that both widthwise ends and the widthwise center of the glass ribbon G are shaped and conveyed. In this case, as the glass ribbon G is shaped and conveyed, the three first sensors 30 switch from the OFF state shown in Figure 10(a) to the ON state shown in Figure 10(b). After this switch, a predetermined short time (e.g., 0.3 to 0.8 seconds, preferably 0.5 seconds) has elapsed, and a pair of holding members 36 are advanced into the second cutting area E2. Here, this predetermined short time is the time required to confirm that the glass ribbon G being shaped and conveyed continues to be detected by the first sensors 30 without breakage, even after the first sensors 30 switch to the ON state. Therefore, advancing the pair of holding members 36 into the second cutting area E2 at this point will prevent glass fragments, etc., falling due to breakage from colliding with the holding members 36.

When the glass ribbon G is further shaped and transported, and the three second sensors 35 switch from OFF to ON as shown in Figure 10(c), the following operation is performed. That is, when a preset time has elapsed since the three second sensors 35 switched ON, the glass ribbon G is cut by the first process described above using the second cutting device 3. Note that this preset time is set as the time required from when the second sensors 35 switch ON until the entire lower end Gz of the glass ribbon G is transported a predetermined distance below the pressing member 41.

Figure 11 illustrates a second example of the above process. This second example illustrates a process in which, by resuming forming after a crack or other defect occurs in the glass ribbon G during the first cutting process, the left end and center of the glass ribbon G are first formed and conveyed, while the right end is formed and conveyed later, as shown in the figure. In this case, as the glass ribbon G is formed and conveyed, the first sensors 30 at the left end and center first turn ON, and the first sensor 30 at the right end turns OFF, as shown in Figure 11(a). When these two first sensors 30 turn ON, only the left-side holding member 36 is advanced into the second cutting area E2. When the glass ribbon G is formed as shown in Figure 11(a), the vertical length of the missing portion Gw on the right side of the lower end Gz of the glass ribbon G is typically short, as shown. Therefore, in this case, three first sensors 30 eventually turn ON, as shown in Figure 11(b). At this point, the right-side holding member 36 is advanced into the second cutting area E2. In this case, if the first sensor 30 that was turned ON after the left-side holding member 36 was advanced turns OFF again, the same measures as in the first example above are taken. Then, if the three second sensors 35 switch from OFF to ON as shown in FIG. 11( c) as the glass ribbon G is further shaped and conveyed downward, the glass ribbon G is cut by the first process described above by the second cutting device 3 after the preset time has elapsed. Note that even if, when shaping of the glass ribbon G resumes here, the right end and central portion of the glass ribbon G in the width direction are shaped and conveyed first, and the left end portion in the width direction is shaped and conveyed later, the glass ribbon G can be cut using the same procedure.

In the second example above, when two first sensors 30 turned ON, only one holding member 36 was advanced into the second cutting area E2. However, when two first sensors 30 turned ON, one holding member 36 may not be advanced into the second cutting area E2, and when three first sensors 30 turned ON, both holding members 36 may be advanced into the second cutting area E2.

Figure 12 illustrates a third example of the above process. This third example illustrates a process in which, as shown in the figure, only the left end G1 of the glass ribbon G in the width direction is shaped and transported by resuming forming after the glass ribbon G is broken during the first cutting process. In this case, as the left end G1 of the glass ribbon G is shaped and transported, the first sensor 30 at the left end first turns ON, and the first sensors 30 at the center and right end turn OFF, as shown in Figure 12(a). When the first sensor 30 at the left end turns ON in this way, only the left-side holding member 36 is advanced into the second cutting area E2. In this case, if the first sensor 30 at the left end turns OFF again after the left-side holding member 36 has advanced, the left-side holding member 36 is retracted and advanced in the same manner as in the first example above. Then, the left end G1 of the glass ribbon G in the width direction is further shaped and conveyed downward, and when the second sensor 35 at the left end switches from OFF to ON as shown in FIG. 12( b), the left end G1 of the glass ribbon G is cut by the second process described above by the second cutting device 3 when the above-mentioned preset time has elapsed. Note that even if only the right end of the glass ribbon G in the width direction is being shaped and conveyed when forming of the glass ribbon G resumes here, the right end of the glass ribbon G in the width direction can be cut using the right-side holding member 36 in the same procedure.

Figure 13 illustrates a fourth example of the above process. This fourth example illustrates a process in which the glass ribbon G is broken during the first cutting process, and then forming is resumed, thereby shaping and conveying the left and right widthwise ends G1 and G2 of the glass ribbon G, as shown in the figure. In this case, as both widthwise ends G1 and G2 of the glass ribbon G are shaped and conveyed, the first sensors 30 at the left and right ends first turn ON, and the central first sensor 30 turns OFF, as shown in Figure 13(a). When the left and right first sensors 30 turn ON in this way, a pair of holding members 36 is advanced into the second cutting area E2. In this case, if at least one of the left-end first sensor 30 and the right-end first sensor 30 turns OFF again after advancing the pair of holding members 36, the corresponding holding member 36 is retracted and advanced in the same manner as in the first example above. Then, the widthwise left end G1 and widthwise right end G2 of this glass ribbon G are further shaped and conveyed downward, and when the second sensors 35 at the left and right ends switch from OFF to ON as shown in FIG. 13(b), the widthwise left end G1 and widthwise right end G2 of the glass ribbon G are cut by the third process already described by the second cutting device 3 once the above-mentioned preset time has elapsed.

In the first to fourth examples described above, the three first sensors 30 constantly detect the presence or absence of glass ribbon G. Therefore, based on the detection results by the first sensors 30 in the first detection process, it is possible to distinguish between a first state in which one of the widthwise end portions of the glass ribbon G is being shaped while being conveyed, a second state in which one of the widthwise end portions and the widthwise central portion of the glass ribbon G are being shaped while being conveyed, a third state in which both widthwise end portions of the glass ribbon G are being shaped while being conveyed, and a fourth state in which the entire widthwise portion of the glass ribbon G is being shaped while being conveyed.

The above first to fourth examples illustrate cases where the glass ribbon G is cut using three first sensors 30 and three second sensors 35, but the glass ribbon G can also be cut using two first sensors 30 and two second sensors 35. In this case, for each of the three first sensors 30 and three second sensors 35, the central sensor 30, 35 may be eliminated and the leftmost and rightmost sensors 30, 35 may be used instead. In this case, three first sensors 30 may be used and the leftmost and rightmost second sensors 35 may be used, or the leftmost and rightmost first sensors 30 may be used and three second sensors 35 may be used.

The above describes a glass sheet manufacturing apparatus and a manufacturing method thereof according to an embodiment of the present invention, but the present invention is not limited to this embodiment, and various modifications are possible without departing from the spirit of the present invention.

In the above embodiment, the glass ribbon G was formed by the overflow downdraw method, but it may also be formed by other downdraw methods such as the slot downdraw method or the redraw method.

In the above embodiment, the glass ribbon G is cut by bending it along the scribe line S in the first cutting step, but it may also be cut by other methods such as laser cutting or laser fusing.

In the above embodiment, the second cutting device 3 is placed below the first cutting device 2, but these devices 2, 3 may also be placed side by side so that part or all of them overlap vertically. In this case, the main body frame 31 of the second cutting device 3 is held in a fixed position, and when the first cutting device 2 is in use, the holding member 36, rotary blade 38, and pressing member 41 are retracted to positions that do not interfere with the operation of the first cutting device 2. The first cutting device 2 and second cutting device 3 may also be mounted (installed) on the same floor wall 23.

In the above embodiment, the holding member 36, rotary blade 38, and pressing member 41 were advanced and retracted without moving the main body frame 31 of the second cutting device 3. However, these members 36, 38, and 41 may also be advanced and retracted while moving the main body frame 31 in the forward and backward directions.

In the above embodiment, a rotary blade 38 was used to cut the glass ribbon G, but any other cutting blade with a cutting edge may be used.

In the above embodiment, two or three first and second sensors 30, 35 are arranged in the width direction, but four or more first and second sensors 30, 35 may also be arranged in the width direction.

In the above embodiment, the holding member 36 is advanced during the switching process. However, if the configuration of the second cutting device 6 differs from that of the above embodiment, other components of the second cutting device (particularly the components that advance from the second evacuation area F2 to the second cutting area E1 earliest) may be advanced. Furthermore, if the means for switching from the first cutting process to the second cutting process is not a means for advancing the components of the second cutting device 6, the switching process may be performed by a means that does not involve the advancement action.

DESCRIPTION OF SYMBOLS 1 Glass ribbon processing device 2 First cutting device 3 Second cutting device 11 Forming zone 30 First sensor 31 Main body frame 32 Holding device 34 Stress applying device 35 Second sensor 36 Holding member 38 Rotary blade (cutting blade)
41 Pressing member E1 First cutting area E2 Second cutting area F1 First evacuation area F2 Second evacuation area G Glass ribbon GS Conveying path of glass ribbon

Claims (10)

A method for manufacturing a glass sheet, comprising: a first cutting step of cutting a glass ribbon being conveyed while being formed by a first cutting device to cut out a glass sheet; and a second cutting step of cutting the glass ribbon by a second cutting device when the first cutting device is not operating,
A method for manufacturing a glass plate, comprising: a first detection process for detecting the presence or absence of a glass ribbon by a sensor upstream of the first cutting device and the second cutting device in the conveying direction ; and a switching process for switching from the first cutting process to the second cutting process when the absence of the glass ribbon is detected in the first detection process. The method for manufacturing a glass sheet according to claim 1, wherein the sensors are installed at multiple locations across the width of the glass ribbon. The method for manufacturing a glass sheet according to claim 1 or 2, wherein the sensors are installed corresponding to at least both widthwise ends and a widthwise middle portion of the glass ribbon, and the detection results in the first detection step make it possible to distinguish between a first state in which one of both widthwise ends of the glass ribbon is being shaped while being conveyed, a second state in which one of both widthwise ends and the widthwise middle portion of the glass ribbon is being shaped while being conveyed, a third state in which both widthwise ends of the glass ribbon are being shaped while being conveyed, and a fourth state in which the entire widthwise portion of the glass ribbon is being shaped while being conveyed. 4. The method for manufacturing a glass sheet according to claim 1 , wherein, in the switching step, when the absence of the glass ribbon is detected in the first detection step, components of the second cutting device are advanced from an evacuation area to a cutting area. 5. The method for manufacturing a glass sheet according to claim 4, wherein the component of the second cutting device is a part of all the components of the second cutting device and is a component that advances earliest among all the components when the cutting process by the second cutting device is started. 6. The method for manufacturing a glass plate according to claim 5, wherein the sensors are installed corresponding to at least both widthwise ends of the glass ribbon, and the components that advance earliest are one or both of the holding members used to hold both widthwise ends of the glass ribbon during cutting in the second cutting step, and the holding member corresponding to the widthwise end of the glass ribbon detected by the sensor to be present is advanced, and the holding member corresponding to the widthwise end of the glass ribbon detected by the sensor to be absent is not advanced. 7. The method for manufacturing a glass sheet according to claim 4, further comprising a second detection step of detecting the presence or absence of a glass ribbon by sensors installed corresponding to at least both widthwise ends of the glass ribbon at positions downstream in the conveying direction from the sensors used in the first detection step, and performing a cutting process of the glass ribbon using components of the second cutting device advanced in the switching step based on the detection results of the sensors. 8. The method for manufacturing a glass sheet according to claim 7 , wherein a component of the second cutting device includes a cutting blade used to cut the glass ribbon, and the cutting blade is pressed against the glass ribbon based on the detection result in the second detection step. 9. The method for manufacturing a glass sheet according to claim 8, wherein components of the second cutting device include a pressing member that applies stress to the glass ribbon, and the pressing member applies stress to the glass ribbon based on a detection result in the second detection step. A glass sheet manufacturing apparatus including: a first cutting device that cuts a glass ribbon that is being formed and transported to cut out a glass sheet; and a second cutting device that cuts the glass ribbon when the first cutting device is not operating,
a sensor for detecting the presence or absence of the glass ribbon upstream of the first cutting device and the second cutting device in the conveying direction , and configured to perform a switching process for switching operation of the first cutting device to operation of the second cutting device when the sensor detects the absence of the glass ribbon .