Method for manufacturing a glass plate and apparatus for cutting a glass ribbon

Abstract

To properly cut a glass ribbon even if the glass ribbon is not in a uniform form.SOLUTION: A manufacturing method for glass plate includes: a first cutting process of cutting a glass ribbon G carried while molded by a first cutting device 2 along its width to obtain glass plates; and a second cutting process of cutting the glass ribbon G by a second cutting device 3, which comprises a cutting blade 38 moving along the width while pressing the glass ribbon G and a holding member 36 holding the glass ribbon G and receiving the pressing force of the cutting blade 38, when the first cutting device 2 is not in operation. In the second cutting process, the pressing force of the cutting blade 38 and / or a moving speed of the cutting blade 38 along the width is varied.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a glass plate, which includes a first cutting step of cutting a glass ribbon being formed and conveyed to cut out a glass plate, and a second cutting step of cutting the glass ribbon when the first cutting step is not performed, and also relates to a cutting device for a glass ribbon that can be used in the second cutting step.

Background Art

[0002] In the field of glass plate manufacturing, it is known to perform a first cutting step of sequentially cutting out glass plates by cutting a glass ribbon that is being formed in a forming zone and continuously moving downward in the width direction at predetermined lengths. In this case, since it is common for a melting furnace or the like of glass plate manufacturing equipment to be continuously operated, even if the cutting device for performing the first cutting step cannot be used during maintenance or the like, the glass ribbon generally continues to be formed. Therefore, even when the first cutting step is not performed, it is necessary to cut and recover the continuously formed glass ribbon.

[0003] In order to meet such requirements, for example, Patent Document 1 discloses performing a second cutting step of cutting a glass ribbon using a cutting device having a configuration different from that of the cutting device in the first cutting step when the first cutting step is not performed. The cutting device used in this second cutting step includes a cutting blade (scoring member) that presses the glass ribbon to score a scratch line, and a holding member that holds the glass ribbon and receives the pressing force of the cutting blade. And the publication discloses that the glass ribbon is cut by applying stress to the glass ribbon while holding the glass ribbon by the holding member and pressing the cutting blade against the stress application portion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, when cutting a glass ribbon, if cutting defects or the like occur, cracks may extend in the longitudinal direction of the glass ribbon and the glass ribbon may be damaged. In addition, the glass ribbon may be scratched by the rollers for conveying the glass ribbon, and the glass ribbon may be damaged. Among these damages, there is a longitudinal crack which is a crack along the longitudinal direction of the glass ribbon. When cutting such a glass ribbon that may be damaged with the cutting device used in the above-described second cutting step, the following problems occur.

[0006] That is, when the glass ribbon is damaged, various forms of missing portions are formed in the glass ribbon. Therefore, when cutting the conveyed glass ribbon, the form of the portion (the portion to be cut) of the glass ribbon is not uniformly determined. To cope with this, it is necessary to vary the length in the width direction to be cut by the cutting blade and the number of cutting locations according to the form of each glass ribbon. In that case, it is difficult to appropriately cut the glass ribbon only by uniformly pressing the cutting blade against the glass ribbon, and it also becomes a factor causing further damage to the glass ribbon.

[0007] From the above viewpoints, an object of the present invention is to enable appropriate cutting of a glass ribbon even when the form of the glass ribbon at the time of cutting is not uniformly determined.

Means for Solving the Problems

[0008] A first aspect of the present invention devised to solve the above problems is a method for manufacturing a glass sheet, including: a first cutting step of cutting a glass ribbon being formed and conveyed along a width direction 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 including a cutting blade that presses the glass ribbon and moves in the width direction and a holding member that holds the glass ribbon and receives the pressing force of the cutting blade when the first cutting device is not in operation. In the second cutting step, either one or both of the pressing force of the cutting blade and the moving speed of the cutting blade in the width direction are used as cutting elements, and the value of the cutting element is changed.

[0009] According to such a configuration, during the execution of the second cutting step, the value of the pressing force of the cutting blade is changed, or the value of the moving speed of the cutting blade in the width direction is changed, or the values of both the pressing force of the cutting blade and the moving speed of the cutting blade in the width direction are changed. Thereby, even if the form of the glass ribbon at the time of cutting is not uniformly determined, the glass ribbon can be appropriately cut. More specifically, when a damaged glass ribbon reaches the periphery of the cutting position, it can take various forms such as having a glass portion only at one end in the width direction or only at both ends in the width direction, or having a narrow missing portion only at a portion near the center in the width direction. Also, the glass ribbon may reach the periphery of the cutting position in a form without a missing portion. When the form of the glass ribbon thus varies, the cutting operation on the glass ribbon can be made suitable for each form by appropriately changing the above-described cutting elements accordingly. Thereby, appropriate cutting of the glass ribbon becomes possible.

[0010] In this configuration, in the second cutting step, the value of the cutting element may be changed based on the detection result of a sensor that detects the presence or absence of the glass ribbon.

[0011] If done in this way, since the form of the glass ribbon can be grasped from the detection result of the sensor, automation of the second cutting device and reduction of the operator's load can be achieved.

[0012] In the above configuration, the sensors are installed corresponding to at least both end portions in the width direction and the middle portion in the width direction of the glass ribbon, the second cutting device includes a pressing member that applies a bending stress in advance to the pressing region of the glass ribbon when pressing the cutting blade against the glass ribbon, and in the second cutting step, based on the detection result of the sensor, it is determined whether or not the pressing member applies a bending stress in advance to the pressing region of the glass ribbon, and the value of the cutting element may be changed based on whether or not the bending stress is applied.

[0013] In this way, since the form of the glass ribbon is detected by the sensors installed at at least three locations, the form of the glass ribbon is known in more detail, and then it is determined whether or not to apply a bending stress. And since the value of the cutting element is changed based on whether or not to apply a bending stress, the value of the cutting element can be made appropriate in either the case where the bending stress is applied and the case where it is not applied.

[0014] In this configuration, when it is detected by the sensor that both end portions in the width direction and the middle portion in the width direction of the glass ribbon are present, the pressing member applies the bending stress, and when it is detected by the sensor that at least one of the end portions of both end portions in the width direction of the glass ribbon is present and the middle portion in the width direction of the glass ribbon is not present, the pressing member may not apply the bending stress.

[0015] In this way, in the case where the portions corresponding to the respective sensors in the glass ribbon are not missing, the cutting blade is pressed in a state where a bending stress is applied to the pressing region of the glass ribbon by the pressing member. As a result, cracks progress starting from the pressing location (scoring line) of the cutting blade, and the glass ribbon is smoothly cut. On the other hand, when it is detected by each sensor that only one end portion in the width direction or only both end portions in the width direction of the glass ribbon are present, the cutting blade is pressed without applying a bending stress, so that a glass ribbon in a form whose length in the width direction has become shorter due to breakage can be easily cut.

[0016] In these configurations, in the second cutting step, a first cutting process is performed in which the pressing member applies the bending stress to cut the glass ribbon, and a second cutting process is performed in which the pressing member cuts the glass ribbon without applying the bending stress. The value of the cutting element in the case of performing the second cutting process may be made larger than the value of the cutting element in the case of performing the first cutting process.

[0017] In this way, since the value of the cutting element is larger when the bending stress is not applied to the glass ribbon than when it is applied, the glass ribbon can be appropriately cut regardless of whether the bending stress is applied or not. More specifically, when the bending stress is applied to the glass ribbon, cracks progress only by scribing a scratch line with the cutting blade, so the value of the pressing force of the cutting blade as the cutting element and its moving speed in the width direction may be small. On the other hand, when the bending stress is not applied to the glass ribbon, the glass ribbon must be cut only by the pressing operation of the cutting blade, so it is necessary to increase the value of the pressing force of the cutting blade and its moving speed in the width direction. According to the configuration here, since such requirements can be accurately met, it becomes possible to cut the glass ribbon more appropriately.

[0018] In the above configuration, the cutting blades are respectively installed corresponding to one end in the width direction and the other end in the width direction of the glass ribbon. The second cutting device includes a pressing member that applies a bending stress in advance to the pressing area of the glass ribbon when pressing the cutting blade against the glass ribbon. When pressing the cutting blade against the glass ribbon with the pressing member applying the bending stress to the glass ribbon, a time difference may be provided between when one cutting blade presses one end in the width direction of the glass ribbon and when the other cutting blade presses the other end in the width direction of the glass ribbon.

[0019] In this way, appropriate cutting can be performed on both the glass ribbon without any missing part and the glass ribbon with a vertically long and narrow missing part near the center in the width direction. Specifically, when one cutting blade and the other cutting blade are simultaneously pressed against the glass ribbon without any missing part, cracks will simultaneously progress from one end in the width direction and the other end in the width direction of the glass ribbon toward the center in the width direction. Therefore, improper cracking or the like may occur starting from the center in the width direction. On the contrary, when one cutting blade is pressed earlier than the other cutting blade, cracks will progress across the entire length in the width direction from only one end in the width direction of the glass ribbon due to the pressing operation of one cutting blade. After that, the other cutting blade will perform the pressing operation. By the time the other cutting blade performs the pressing operation, since the glass ribbon has been cut, even if the pressing operation is performed, the other cutting blade will not contact the glass ribbon, and it is possible to avoid the occurrence of improper cracking or the like in the glass ribbon as described above. Also, when one cutting blade is pressed earlier than the other cutting blade against the glass ribbon with a vertically long and narrow missing part near the center in the width direction, when the crack progressing from one end in the width direction of the glass ribbon reaches the missing part due to the pressing operation of one cutting blade, the cutting of the part on the one end side of the glass ribbon is completed. Subsequently, when the other cutting blade presses the other end in the width direction of the glass ribbon, the remaining part of the glass ribbon is cut as the crack progresses from the other end. Therefore, there is no obstacle to cutting for both the glass ribbon without any missing part and the glass ribbon with the above-mentioned predetermined missing part.

[0020] In this configuration, it is preferable that the time difference is 0.1 to 1.0 seconds.

[0021] In this way, without causing a wasteful time delay, the above-mentioned advantages can be accurately obtained.

[0022] In the above configuration, each time the cutting using the cutting blade is performed, the holding member may be advanced to a holding position where the glass ribbon can be held, and each time the cutting using the cutting blade is completed, the holding member may be retracted to a retracted position where it does not interfere with the glass ribbon.

[0023] In this way, it is possible to appropriately handle the problem that the holding member cannot hold the glass ribbon. Specifically, since the glass ribbon immediately after cutting has vibrations and twists, etc., a situation may occur where the glass ribbon wraps around from the holding side (the side in contact with the glass ribbon) of the holding member to the opposite side. And if the glass ribbon is conveyed in such a wrapped state, the holding member can no longer hold the glass ribbon. The occurrence of such a problem becomes particularly prominent when the crack in the glass ribbon progresses not along the width direction (preferably the horizontal direction) but in an oblique direction. According to the configuration here, each time the glass ribbon is cut, the holding member is advanced to the holding position, and each time the cutting is completed, the holding member is retracted to the retracted position, so such a problem does not occur. Moreover, since the advancement and retraction of the holding member are performed by the control device without the intervention of the operator, the automation of the operation of the holding member is promoted.

[0024] In this configuration, it is preferable to move the holding member from the holding position toward the retracted position within 1 second after the cutting using the cutting blade is completed.

[0025] In this way, even when the glass ribbon wraps around from the holding side of the holding member to the opposite side, the holding member can be moved from the holding position to the retracted position before the distance between the lower end of the wrapped glass ribbon and the holding member increases. Therefore, the amount of deformation of the glass ribbon accompanying the movement of the holding member to the retracted position can be suppressed, and breakage of the glass ribbon can be prevented.

[0026] A second aspect of the present invention devised to solve the above problems is a glass ribbon cutting device including a cutting blade that presses a glass ribbon being formed and conveyed and moves in the width direction, and a holding member that holds the glass ribbon and receives the pressing force of the cutting blade, characterized in that it includes a control device that changes the value of a cutting element, where either one or both of the pressing force of the cutting blade and the moving speed of the cutting blade in the width direction are used as the cutting element.

[0027] This glass ribbon cutting device changes the value of the cutting element in the same manner as the above-described glass plate manufacturing method. Therefore, according to this glass ribbon cutting device, substantially the same operational effects as the corresponding above-described manufacturing method can be obtained. In addition, since the above-described change of the cutting element is performed by the control device without the intervention of an operator, the automation of the operation of the cutting blade during cutting is promoted.

Effects of the Invention

[0028] According to the present invention, the glass ribbon can be appropriately cut even if the form of the glass ribbon during cutting is not uniformly determined.

Brief Description of the Drawings

[0029]

Figure 1

Figure 2

Figure 3

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Figure 6

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Figure 8

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Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Embodiments for Carrying Out the Invention

[0030] Hereinafter, embodiments according to the present invention will be described based on the accompanying drawings.

[0031] FIG. 1 is a side view showing the overall configuration of a manufacturing apparatus for implementing a method for manufacturing a glass plate according to the present embodiment. As shown in this figure, this manufacturing apparatus includes, as main components, a processing apparatus 1 for a glass ribbon G, a first cutting apparatus 2, and a second cutting apparatus 3. In the following description, the first main surface Ga side (arrow X1 side in FIG. 1) of the glass ribbon G is referred to as the "rear side", and the second main surface Gb side (arrow Y1 side in FIG. 1) is referred to as the "front side". Also, in the present embodiment, the downstream side in the conveyance direction of the glass ribbon G is "downward (preferably vertically downward)", and the upstream side is "upward (preferably vertically upward)".

[0032] The processing apparatus 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 conveyance apparatus 14 composed of a pair of rollers R provided in a plurality of upper and lower stages in each of the forming zone 11, the heat treatment zone 12, and the cooling zone 13.

[0033] The forming zone 11 and the heat treatment zone 12 are constituted by a furnace in which the periphery of the conveyance path of the glass ribbon G is surrounded by a wall portion, and a heating device such as a heater for adjusting the temperature of the glass ribbon G is disposed at an appropriate position in the furnace. On the other hand, the cooling zone 13 is open to the external atmosphere without the periphery of the conveyance path of the glass ribbon G being surrounded by a wall portion, and no heating device such as a heater is disposed.

[0034] In the internal space of the forming zone 11, a forming body 15 for forming the glass ribbon G from molten glass Gm by the overflow down-draw method is disposed. The molten glass Gm supplied to the forming body 15 overflows from a groove portion (not shown) formed at the top portion 15a of the forming body 15. The overflowed molten glass Gm flows along both side surfaces 15b having a wedge-shaped cross section of the forming body 15 and joins at the lower end. Thereby, a plate-shaped glass ribbon G is continuously formed. This continuously formed glass ribbon G is conveyed downward in a vertical posture (preferably a vertical posture).

[0035] The internal space of the heat treatment zone 12 has a predetermined temperature gradient downward. As the vertically oriented glass ribbon G moves downward through the internal space of the heat treatment zone 12, it is heat treated (slowly cooled) so that its temperature decreases. This heat treatment suppresses the generation of unintended thermal distortion in the glass ribbon G. The temperature gradient of the internal space of the heat treatment zone 12 is adjusted, for example, by a heating device provided on the inner surface of the wall portion of the heat treatment zone 12.

[0036] The plurality of roller pairs R constituting the conveying device 14 sandwich both widthwise ends of the vertically oriented glass ribbon G from the front and back sides. The uppermost roller pair R disposed in the forming zone 11 is a cooling roller. Note that in the internal space of the heat treatment zone 12 and the like, among the plurality of roller pairs R, there may be those that do not sandwich the widthwise ends of the glass ribbon G.

[0037] In the present embodiment, both widthwise ends of the glass ribbon G manufactured by the processing device 1 have portions (hereinafter also referred to as "ear portions") with a greater thickness compared to the central portion in the width direction due to the influence of shrinkage during the forming process and the like.

[0038] The first cutting device 2 is used in the first cutting step of the method for manufacturing a glass plate according to the present embodiment. This first cutting device 2 is configured to sequentially cut out glass plates from the glass ribbon G by cutting the vertically oriented glass ribbon G in the width direction at predetermined lengths below the processing device 1. The cut-out glass plates have their ear portions removed in a subsequent process. The glass plates with their ear portions removed become glass mother plates from which one or more product glass plates are collected. Here, the width direction is a direction orthogonal to the longitudinal direction (conveying direction) of the glass ribbon G and parallel to both main surfaces Ga and Gb of the glass ribbon G, and substantially coincides with the horizontal direction in the present embodiment. In the following description, when the glass ribbon G is viewed from the rear as shown in FIG. 2, the side of the arrow X2 in the figure is taken as the left side in the width direction, and the side of the arrow Y2 in the figure is taken as the right side in the width direction.

[0039] As shown in FIGS. 1 and 2, the first cutting device 2 includes a scribe line forming device 21 and a breaking device 22.

[0040] The scribe line forming device 21 is a device that forms a scribe line S on the first main surface Ga of the vertically oriented glass ribbon G that has descended from the processing device 1 at the scribe line forming position P1. In the present embodiment, the scribe line forming device 21 includes a wheel cutter 23 that forms a scribe line S along the width direction of the first main surface Ga of the glass ribbon G, and a support member 24 (for example, a support bar or a support roller) that supports the second main surface Gb of the glass ribbon G at a position corresponding to the wheel cutter 23. Note that the scribe line S may be formed by laser irradiation or the like.

[0041] The breaking device 22 is a device that cuts out a glass plate by breaking the glass ribbon G along the scribe line S at a breaking position P2 provided below the scribe line forming position P1. In the present embodiment, the breaking device 22 includes a breaking member 25 that abuts from the second main surface Gb side against the region where the scribe line S is formed, and a gripping mechanism 26 that grips the lower region of the glass ribbon G below the breaking position P2.

[0042] The breaking member 25 is composed of a plate-like body (surface plate) having a contact surface (arc-shaped in side view) that contacts the entire width direction or a part of the glass ribbon G. The contact surface of the breaking member 25 may be a curved surface that is curved in the width direction in plan view.

[0043] The gripping mechanism 26 includes chucks 27 disposed at a plurality of positions in the vertical direction at both ends in the width direction of the glass ribbon G, and arms 28 that hold the plurality of chucks 27 at both ends in the width direction, respectively. Note that the chucks 27 may be changed to other holding forms such as holding the glass ribbon G by negative pressure adsorption.

[0044] The second cutting device 3 is used in the second cutting step of the method for manufacturing a glass sheet according to the present embodiment. This second cutting device 3 is disposed below the first cutting device 2 and cuts the glass ribbon G that is being formed in the forming zone 11 and conveyed downward when the first cutting device 2 is not in operation (for example, during maintenance or when restarting the forming of the glass ribbon G).

[0045] The second cutting device 3 includes a main body frame 31 formed of a framework disposed behind the glass ribbon G. At the front end of the main body frame 31, a pair of holding devices 32, a pair of grooving devices 33, and a stress applying device 34 are installed in order from above.

[0046] The pair of holding devices 32 includes columnar holding members 36 respectively corresponding to both end portions in the width direction of the glass ribbon G. Each of the pair of holding members 36 is configured to rotate integrally with a rotation shaft 37 (see FIGS. 3 and 4) at the front end of a holding arm 36a. Each of the pair of holding arms is held on a base portion 36b installed at the upper end of the main body frame 31 (see FIG. 5). Also, the pair of holding members 36 are held at the same height position and each has a function of rotating independently. Further, with each rotation movement of the pair of holding members 36, as shown in FIG. 3, they are in a retracted state (shown by a solid line in FIG. 5) retracted to a retracted position where they do not interfere with the glass ribbon G, and as shown in FIG. 4, they are in an advanced state (shown by a chain line in FIG. 5) advanced to a holding position where they can hold the glass ribbon G. In this case, when the pair of holding members 36 are retracted to the retracted position, they are in a state of being spaced outward in the width direction from both end portions in the width direction of the glass ribbon G and extending in the front-rear direction, and when advanced to the holding position, they are in a state of extending in the left-right direction (width direction) to hold the second main surface Gb of the glass ribbon G. Also, each of the pair of holding members 36 is rotatable about its respective central axis 36x (see FIGS. 3 and 4).

[0047] The pair of cutting devices 33 includes cutting blades 38 respectively arranged corresponding to both end portions in the width direction of the glass ribbon G. Each of the pair of cutting blades 38 is configured to project and retract in the front-rear direction (the direction inclined upward toward the front in the illustrated example). Further, the pair of cutting blades 38 are held at the same height position and are configured to project and retract independently of each other. Furthermore, with the retraction of each of the pair of cutting blades 38, as shown in FIG. 3, it is in a state of retracting rearward from the glass ribbon G (the state shown by the solid line in FIG. 5). Also, with the projection of each of the pair of cutting blades 38, as shown in FIG. 4, it is in a state of pressing both end portions in the width direction of the glass ribbon G (the state shown by the dashed-dotted line in FIG. 5). Each individual cutting blade 38 is configured to move in the width direction while pressing both end portions in the width direction of the glass ribbon G from the side of the first main surface Ga when in this pressing state.

[0048] The stress applying device 34 has a pressing member 41 for applying a bending stress to the glass ribbon G. The pressing member 41 is attached to the tips of a pair of swing arms 40 swingable around a support shaft 39 (see FIGS. 2 and 5). The pressing member 41 is formed by arranging a plurality of (four in the illustrated example) rollers 41a in series along the width direction and is longer than the length in the width direction of the glass ribbon G. The plurality of rollers 41a are rotatable around a central axis 41x extending in the width direction (see FIGS. 2 and 3). Further, the pressing member 41 is configured to change between a state of retracting rearward from the glass ribbon G as shown in FIG. 3 (the state shown by the solid line in FIG. 5) and a state of pressing the glass ribbon G as shown in FIG. 4 (the state shown by the dashed-dotted line in FIG. 5).

[0049] Furthermore, the second cutting device 3 includes a control device 42 (see FIGS. 6 and 7). As shown in FIG. 5, the control device 42 has a sensor 43 for detecting the presence or absence of the glass ribbon G. In the illustrated example, the sensor 43 is disposed behind the conveyance path of the glass ribbon G by being fixed to the main body frame 31. Further, the sensor 43 is disposed at a height position intermediate between the support shaft 39 at the upper end and the pressing member 41 at the lower end of the stress applying device 34. In this case, as shown in FIG. 2, a plurality of sensors 43 are installed corresponding to a plurality of positions in the width direction of the glass ribbon G. In the present embodiment, a total of three sensors 43 are installed at positions corresponding to both end portions in the width direction of the glass ribbon G and at a position corresponding to the central portion in the width direction. These sensors 43 are fixed to the front end portion of the main body frame 31 so as to be aligned in the width direction and are held at a fixed position. As the sensor 43, a laser sensor, an ultrasonic sensor, a thermosensor, or the like is used. Note that the sensor 43 constantly detects the presence or absence of the glass ribbon G.

[0050] The control device 42 has a function of reflecting the detection results by the three sensors 43 in the rotational movement of each holding member 36. The configuration and operation of the control device 42 in this case are as follows. That is, as shown in FIG. 6, the signals from the three sensors 43 are sent to the control unit 44. As the control unit 44, a microcomputer or a personal computer can be used, but other known control means may also be used. A signal is sent from the control unit 44 to the rotation controller 45, and based on the signal from the rotation controller 45, the holding member 36 rotates. At this time, the tip of the holding member 36 moves along an arc as indicated by the arrow A. Here, based on this figure, the drive unit 46 of the holding member 36 will be described in detail. In this figure, the drive unit 46 of one holding member 36 is shown in detail, but the drive unit 46 of the other holding member 36 has the same configuration. The drive unit 46 includes a winding transmission mechanism 47 for rotating the holding member 36. The winding transmission mechanism 47 includes a drive pulley 49 that is rotationally driven by a motor 48, a driven pulley 50 fixed to a rotating shaft 37 that rotates integrally with the holding member 36, and a belt 51 wound around the drive pulley 49 and the driven pulley 50. The belt 51 may be a timing belt or other winding members (such as a chain). According to this configuration, the rotational driving force of the motor 48 is transmitted to the rotating shaft 37 via the drive pulley 49, the belt 51, and the driven pulley 50. Thereby, the holding member 36 rotates between the holding position (the position when in the state shown by the solid line) and the retracted position (the position when in the state shown by the dashed line). Note that the angle by which the holding member 36 rotates is 90° in the illustrated example with respect to the holding member 36 when in the holding position, but it is preferably 80° or more and 180° or less. Also, the forward and reverse rotation control and the rotation speed control of the holding member 36 are performed by the rotation controller 45 that receives a signal from the control unit 44. Note that the rotation controller 45 may be incorporated in the control unit 44. Also, instead of the winding transmission mechanism 47, the drive unit 46 may use a gear transmission mechanism similar to the case described later, or other known mechanisms having the same functions as these may also be used.

[0051] Furthermore, the control device 42 has a function of reflecting the detection results by the three sensors 43 in the pressing operation of each cutting blade 38. The configuration and operation of the control device 42 in this case are as follows. That is, as shown in FIG. 7, also in this case, signals from the three sensors 43 are sent to the control unit 44. In this embodiment, the control unit 44 is the same as the aforementioned control unit 44, but it may also be a separate control unit. And the cutting elements of each cutting blade 38 are the pressing force of the cutting blade 38 against the glass ribbon G and the moving speed of the cutting blade 38 in the width direction, and the values of these cutting elements can be changed. As a configuration for that, a signal is sent from the control unit 44 to the regulator 52, and the pressing force of the cutting blade 38 is regulated based on the operation of the regulator 52. Furthermore, a signal is sent from the control unit 44 to the rotation controller 53, and the turning movement speed of the cutting blade 38 is adjusted based on the signal from the rotation controller 53, and accordingly, the moving speed of the cutting blade 38 in the width direction is adjusted. Here, based on this figure, the drive unit 54 of the cutting blade 38 will be described in detail. In the figure, the drive unit 54 of one cutting blade 38 is shown in detail, but the drive unit 54 of the other cutting blade 38 also has the same configuration. The drive unit 54 includes a fluid pressure cylinder 55 such as an air cylinder that causes the cutting blade 38 to project and retract. The cutting blade 38 is fixed to the tip of the extension / retraction rod 55a of the fluid pressure cylinder 55. The rear end portion of the fluid pressure cylinder 55 is fixed to a substrate 56 that rotates at a fixed position at the front end portion of the main body frame 31. Therefore, if the regulator 52 is installed in the fluid supply path of the fluid pressure cylinder 55, the control unit 44 can cause the extension / retraction rod 55a of the fluid pressure cylinder 55 to project while regulating the pressure. And the value of the pressing force of the cutting blade 38 is changed by the operation of the regulator 52 that has received the signal from the control unit 44. In this case, the control unit 44 stores in advance the value of the first pressing force and the value of the second pressing force that is larger than the value of the first pressing force. The value of the second pressing force is preferably 5 times or more and 20 times or less the value of the first pressing force, and more preferably the lower limit value is 7 times and / or the upper limit value is 15 times.In addition, the drive unit 54 includes a gear transmission mechanism 57 that causes the cutting blade 38 to pivotally move in the width direction as indicated by the arrow B. This pivotal movement has a convex center portion of the movement locus facing forward. The gear transmission mechanism 57 includes a small-diameter drive gear 59 that is rotationally driven by a motor 58, and a large-diameter driven gear 60 that meshes with the drive gear 59. A rotating shaft 61 that rotates integrally with the driven gear 60 is fixed to the substrate 56. Note that the rotating shaft 61 is rotatably supported by a base 62 via a bearing (not shown). According to this configuration, the rotational driving force of the motor 58 is transmitted from the drive gear 59 to the substrate 56 and the fluid pressure cylinder 55 via the driven gear 60 and the rotating shaft 61. As a result, the substrate 56 and the fluid pressure cylinder 55 rotate integrally around the rotating shaft 61, causing the cutting blade 38 to pivotally move. Further, the pivotal movement speed of the cutting blade 38 is changed by a rotation controller 53 that has received a signal from the control unit 44. In this case, the control unit 44 stores in advance a value of a first pivotal movement speed and a value of a second pivotal movement speed that is greater than the value of the first pivotal movement speed. Also, the forward and reverse rotations of the cutting blade 38 are controlled by the rotation controller 53 that has received a signal from the control unit 44. Further, a time difference is provided between when one cutting blade 38 pivotally moves and when the other cutting blade 38 pivotally moves, also by the rotation controller 53 that has received a signal from the control unit 44. Note that the rotation controller 53 may be incorporated in the control unit 44. Also, instead of the gear transmission mechanism 57, the drive unit 54 may use a winding transmission mechanism similar to that in the above-described case, or may use other known mechanisms having similar functions.

[0052] The pressing member 41 moves between a retracted position and a pressing position, and this movement of the pressing member 41 is also performed based on a signal from the control unit 44 of the control device 42. Also in this case, signals from the three sensors 43 are sent to the control unit 44. The control unit 44 is the same as the above-described control unit 44 in this embodiment, but may be a separate control unit. Note that the description of the configuration of the drive unit of the pressing member 41 is omitted, and the pressing member 41 may be moved between a retracted position and a pressing position using a fluid pressure cylinder or a ball screw mechanism or the like.

[0053] Next, a method for manufacturing a glass plate implemented using the manufacturing apparatus for a glass plate configured as described above will be described.

[0054] The method for manufacturing a glass plate according to the present embodiment includes a forming step, a conveying step, a first cutting step, and a second cutting step.

[0055] The forming step is a step of forming a glass ribbon G in a forming zone 11. The conveying step is a step of conveying the formed glass ribbon G by a roller pair R of a conveying device 14. The conveying step includes a heat treatment step and a cooling step. The heat treatment step is a step of performing heat treatment on the glass ribbon G while conveying the glass ribbon G that has undergone the forming step in a heat treatment zone 12. The cooling step is a step of cooling the glass ribbon G that has undergone the heat treatment step while conveying it in a cooling zone 13.

[0056] The first cutting step is a step of obtaining a glass plate by cutting the glass ribbon G in the width direction with a first cutting device 2 while conveying the glass ribbon G that has undergone the cooling step. More specifically, as shown in FIGS. 1 and 2, in the first cutting step, first, a wheel cutter 23 and a support member 24 move following the glass ribbon G that continuously moves downward, and a scribe line S is formed over the entire width or part of the width direction of the glass ribbon G. In the present embodiment, the scribe line S is also formed on the relatively thick ear portion. Next, after a plurality of chucks 27 grip the glass ribbon G, an arm 28 moves the plurality of chucks 27 following the glass ribbon G. At this time, the folding member 25 also moves following the glass ribbon G. While these movements are being performed, the arm 28 performs an operation (an operation in the C direction shown in FIG. 1) for bending the glass ribbon G with the folding member 25 as a fulcrum. Thereby, bending stress is applied to the scribe line S and its vicinity, and the glass ribbon G is folded in the width direction along the scribe line S. As a result of this cutting by folding, a glass plate is cut out from the glass ribbon G.

[0057] The second cutting process is a process of cutting the glass ribbon G using the second cutting device 3 when the first cutting device 2 is not in operation. When the second cutting device 3 is in use, each component of the first cutting device 2 is retracted to a position that does not interfere with the cutting process performed by the second cutting device 3. Hereinafter, the cutting process performed by the second cutting device 3 will be described. In the following description, the case where the glass ribbon G is detected by the sensor 43 is described as "ON".

[0058] Figures 8 to 10 show a first example of the cutting process performed by the second cutting device 3. In this first example, the glass ribbon G conveyed to the vicinity of the cutting position L1 does not have a missing portion. Therefore, as shown in FIG. 8, when the glass ribbon G passes through the arrangement position of the sensor 43, the three sensors 43 turn ON. In FIG. 8, the three ○ marks arranged at the intermediate position in the vertical direction of the second cutting device 3 are the detection regions 43a of the three sensors 43 (the same applies to FIGS. 11 to 14 described later). In this first example, first, signals indicating that the three sensors 43 are ON are sent to the control unit 44, and the control unit 44 operates the drive unit 46 of the holding member 36 through the rotation controller 45. As a result, the pair of holding members 36 rotate from the state of extending along the front-rear direction at the retracted position shown by the dashed line in FIG. 9 to the state of extending along the width direction at the holding position shown by the solid line. At this point, in the illustrated example, there is a slight gap between the pair of holding members 36 and the glass ribbon G, but the two 36 and G may be in contact. After that, based on the signal from the control unit 44, the pressing member 41 moves from the retracted state to the pressing state, and bends the stress is applied to the pressing region Gx of the glass ribbon G as shown by the dashed line in FIG. 5. At this point, the glass ribbon G is held by the pair of holding members 36. In this state, the control unit 44 projects the advancing / retracting rod 55a of the fluid pressure cylinder 55 and moves the cutting blade 38 closer to the pressing region Gx of the glass ribbon G. From this state, the control unit 44 causes one cutting blade 38 to perform an operation of pressing the glass ribbon G as shown in FIG. 10. As a result, one cutting blade 38 pivots in the direction of arrow B1 while pressing the glass ribbon G. The value of the pressing force of the cutting blade 38 at this time is set to the value of the first pressing force (a relatively small value). Also, the value of the pivoting movement speed of the cutting blade 38 at this time is set to the value of the first pivoting movement speed (a relatively small value). As a result, a scratch line with a relatively shallow cut depth is engraved at one end in the width direction of the glass ribbon G. Then, starting from this scratch line, a crack propagates over the entire length in the width direction of the glass ribbon G, and the glass ribbon G is cut.At this time, the other cutting blade 38 is in a standby state. Then, the control unit 44 causes the other cutting blade 38 to perform an operation of pressing the glass ribbon G. As a result, the other cutting blade 38 rotates while moving in the direction of pressing the glass ribbon G. In this case, there is a time difference of 0.1 to 1.0 seconds (preferably 0.1 to 0.7 seconds) between the time when one cutting blade 38 performs the pressing operation and the time when the other cutting blade 38 performs the pressing operation. At the time when the other cutting blade 38 performs the pressing operation, since the glass ribbon G has been cut, the other cutting blade 38 lightly contacts or does not contact the lower end portion of the glass ribbon G after cutting. Therefore, cracks or the like do not occur in the glass ribbon G after cutting. Within 1 second from the time when this cutting is completed, the holding member 36 rotates from the holding position to the retracted position. After that, when the glass ribbon G is conveyed by a predetermined length, the holding member 36 rotates again from the retracted position to the holding position, and the same cutting operation as described above is performed. Such a cutting operation is repeated as long as the glass ribbon G is conveyed without having a missing portion. As shown in FIGS. 1 and 2, the glass after cutting becomes unnecessary glass Gy and falls downward, and is collected in the collection area 63 (the same applies to the second to fourth examples below). Therefore, an opening 65 for dropping the cut glass into the collection area 63 is formed in the floor wall 64 on which the second cutting device 3 is mounted (see FIGS. 1 to 4).

[0059] Figures 11 and 12 show a second example of the cutting process performed by the second cutting device 3. In this second example, the glass ribbon G conveyed to the vicinity of the cutting position L1 has a vertically long and narrow missing portion Gz at a portion slightly shifted from the center in the width direction to one side (the right side in the illustrated example). Therefore, as shown in FIG. 11, when the glass ribbon G passes through the position where the sensor 43 is disposed, three sensors 43 are turned on in the same manner as in the above-described first example. Therefore, the cutting operation of the glass ribbon G in this second example is performed in the same manner as in the above-described first example. That is, first, after the pair of holding members 36 are respectively rotated from the retracted position to the holding position, the pressing member 41 applies a bending stress to the pressing region Gx of the glass ribbon G. In this state, the cutting blade 38 is moved close to the pressing region Gx of the glass ribbon G, and while pressing one cutting blade 38 against the glass ribbon G, it is rotated. The value of the pressing force of the cutting blade 38 is set to the value of the first pressing force, and the value of the rotational movement speed of the cutting blade 38 is set to the value of the first rotational movement speed. As a result, starting from the scratch line engraved on one end portion in the width direction of the glass ribbon G, a crack propagates in the width direction, so that the left side portion G1 of the missing portion Gz of the glass ribbon G is cut as shown in FIG. 12, and the right side portion G2 is not cut. After that, while rotating the other cutting blade 38 while pressing it against the right side portion G2 of the glass ribbon G, a scratch line is engraved on the other end portion in the width direction of the glass ribbon G to cut the right side portion G2. Also in this case, there is a time difference of 0.1 to 1.0 seconds (preferably 0.1 to 0.7 seconds) between when one cutting blade 38 performs the pressing operation and when the other cutting blade 38 performs the pressing operation. Within 1 second from the time when this cutting is completed, the pair of holding members 36 are respectively rotated from the holding position to the retracted position. After that, when the glass ribbon G is conveyed by a predetermined length, the pair of holding members 36 are respectively rotated from the retracted position to the holding position again, and the same cutting operation as described above is performed. Such a cutting operation is repeated as long as the glass ribbon G is conveyed in a state having a vertically long and narrow missing portion Gz at a portion slightly shifted from the center in the width direction to one side.

[0060] FIG. 13 shows a third example of the cutting process performed by the second cutting device 3. In this third example, only one end portion in the width direction of the glass ribbon G (the left end portion in the illustrated example) G3 is conveyed to the vicinity of the cutting position L1. Therefore, as shown in this figure, when the left end portion G3 of the glass ribbon G passes through the arrangement position of the sensor 43, only the leftmost sensor 43 is turned ON. Therefore, in this third example, first, a signal indicating that it is ON is sent from the leftmost sensor 43 to the control unit 44, and the control unit 44 rotates only the left holding member 36 from the retracted position to the holding position through the rotation controller 45. In this case, the control unit 44 maintains the pressing member 41 in the retracted state. Therefore, no bending stress is applied to the left end portion G3 of the glass ribbon G. In this state, the control unit 44 projects the extension / retraction rod 55a of the left fluid pressure cylinder 55 to move the left cutting blade 38 closer to the pressing region Gx of the glass ribbon G. From this state, the control unit 44 causes the left cutting blade 38 to perform an operation of pressing the glass ribbon G. As a result, the left cutting blade 38 rotates while pressing the glass ribbon G. The value of the pressing force of the cutting blade 38 at this time is set to the value of the second pressing force (relatively large value). Also, the value of the rotational movement speed of the cutting blade 38 at this time is set to the value of the second rotational movement speed (relatively large value). As a result, a scratch line with a relatively deep cut depth is engraved on the left end portion G3 of the glass ribbon G, and this scratch line is strongly pushed in by the left cutting blade 38, so that so-called push cutting is performed. Thereby, the left end portion G3 of the glass ribbon G is cut. Within 1 second from the time when this cutting is completed, the left holding member 36 rotates from the holding position to the retracted position. After that, when the left end portion G3 of the glass ribbon G is conveyed by a predetermined length, the left holding member 36 rotates again from the retracted position to the holding position, and the same cutting operation as described above is performed. Such a cutting operation is repeated as long as only the left end portion G3 of the glass ribbon G is conveyed. In addition, when only the right end portion of the glass ribbon G is conveyed, only the rightmost sensor 43 is turned ON, and the same cutting operation is performed by the right holding member 36 and the right cutting blade 38.

[0061] FIG. 14 shows a fourth example of the cutting process performed by the second cutting device 3. In this fourth example, only both end portions G4 and G5 in the width direction of the glass ribbon G are conveyed to the vicinity of the cutting position L1. Therefore, as shown in the figure, when both end portions G4 and G5 in the width direction of the glass ribbon G pass through the arrangement positions of the sensors 43, only the sensors 43 at the left end and the right end are turned ON. Therefore, in this fourth example, first, signals indicating that they are ON are sent from the sensors 43 at the left end and the right end to the control unit 44, and the control unit 44 rotates the holding members 36 on both the left and right sides from the retracted position to the holding position through the rotation controller 45. Also in this case, the control unit 44 maintains the pressing member 41 in the retracted state as in the above-described third example. Therefore, no bending stress is applied to both end portions G4 and G5 in the width direction of the glass ribbon G. In this state, the control unit 44 projects the advancing / retracting rods 55a of the fluid pressure cylinders 55 on both the left and right sides to move the cutting blades 38 on both the left and right sides closer to the pressing region Gx of the glass ribbon G. From this state, the control unit 44 causes the cutting blades 38 on both the left and right sides to perform an operation of pressing both end portions G4 and G5 in the width direction of the glass ribbon G, respectively. As a result, the cutting blades 38 on both the left and right sides perform a turning movement while pressing both end portions G4 and G5 in the width direction of the glass ribbon G, respectively. The value of the pressing force of the cutting blades 38 on both the left and right sides at this time is set to the value of the second pressing force (relatively large value). Also, the value of the turning movement speed of the cutting blades 38 on both the left and right sides at this time is set to the value of the second turning movement speed (relatively large value). Therefore, also in this fourth example, as in the above-described third example, the scratch lines formed on both end portions G4 and G5 in the width direction of the glass ribbon G are strongly pressed by the cutting blades 38 on both the left and right sides, respectively, so that so-called pressing and splitting is performed. As a result, the left end portion G4 and the right end portion G5 of the glass ribbon G are respectively cut. The cutting operation in this case is performed simultaneously by the cutting blade 38 on the right side and the cutting blade 38 on the left side, but may be performed with a time difference as in the above-described first and second examples. Within 1 second from the time when this cutting is completed, the holding members 36 on both the left and right sides rotate from the holding position to the retracted position, respectively.After that, when both end portions G4 and G5 in the width direction of the glass ribbon G are conveyed by a predetermined length, the holding members 36 on both the left and right sides rotate again from the retracted position to the holding position, and the same cutting operation as described above is performed. Such a cutting operation is repeated as long as only both end portions G4 and G5 in the width direction of the glass ribbon G are conveyed.

[0062] As described above, the method for manufacturing a glass plate and the cutting device (second cutting device) for a glass ribbon according to the embodiment of the present invention have been described. However, the embodiment of the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention.

[0063] In the above embodiment, the glass ribbon G is formed by the overflow down-draw method, but it may be formed by other down-draw methods such as the slot down-draw method or the redraw method.

[0064] In the above embodiment, in the first cutting step, the glass ribbon G is cut by being folded along the scribe line S, but it may be cut by other methods such as laser cutting or laser welding.

[0065] In the above embodiment, the second cutting device 3 is arranged below the first cutting device 2, but the two devices 2 and 3 may be arranged in parallel so that a part or all of the two devices 2 and 3 overlap in the vertical direction. In this case, the main body frame 31 of the second cutting device 3 is held at a fixed position, and when the first cutting device 2 is used, the holding member 36, the cutting blade 38, and the pressing member 41 may be retracted to a position that does not interfere with the operation of the first cutting device 2. Further, the first cutting device 2 and the second cutting device 3 may be mounted (installed) on the same floor wall 64.

[0066] In the above embodiment, the glass ribbon G is cut without moving the main body frame 31 of the second cutting device 3, but the glass ribbon G may be cut while moving the main body frame 31 in the front-rear direction.

[0067] In the above-described embodiment, the disc-shaped cutting blade 38 is used to cut the glass ribbon G. However, as long as it has a cutting edge, a cutting blade of another shape may be used.

[0068] In the above-described embodiment, three sensors 43 are arranged in the width direction. However, four or more sensors 43 may be arranged in the width direction.

[0069] In the above-described embodiment, the cutting blade 38 is moved in a turning motion so as to move the cutting blade 38 in the width direction of the glass ribbon G. However, the cutting blade 38 may be moved in the width direction of the glass ribbon G by moving it parallel to both main surfaces Ga and Gb of the glass ribbon G in a state where the cutting blade 38 is biting into the glass ribbon G.

[0070] In the above-described embodiment, the value of the cutting element is automatically changed by the control device 42. However, the value of the cutting element may be changed by the operation of an operator.

Explanation of Reference Numerals

[0071] 2 First cutting device 3 Second cutting device 36 Holding member 38 Cutting blade 41 Pressing member 42 Control device 43 Sensor G Glass ribbon G3 One end portion (left end portion) in the width direction of the glass ribbon G4 One end portion (left end portion) in the width direction of the glass ribbon G5 The other end portion (right end portion) in the width direction of the glass ribbon

Claims

Claim 1 A method for cutting a glass ribbon, comprising: a first cutting step of cutting a glass ribbon being formed and conveyed along a width direction by a first cutting device to cut out a glass plate; and a second cutting step of cutting the glass ribbon by a second cutting device including a cutting blade that presses the glass ribbon and moves in the width direction and a holding member that holds the glass ribbon and receives the pressing force of the cutting blade when the first cutting device is not in operation, wherein in the second cutting step, either one or both of the pressing force of the cutting blade and the moving speed of the cutting blade in the width direction are used as cutting elements, and the value of the cutting element is changed based on a detection result of a sensor that detects the presence or absence of the glass ribbon. Claim 2 The sensor is installed corresponding to at least both end portions in the width direction and an intermediate portion in the width direction of the glass ribbon, and the second cutting device includes a pressing member that applies a bending stress in advance to a pressing region of the glass ribbon when pressing the cutting blade against the glass ribbon. In the second cutting step, based on the detection result of the sensor, it is determined whether or not the pressing member applies a bending stress in advance to the pressing region of the glass ribbon, and based on whether or not the bending stress is applied, the value of the cutting element is changed. The method for cutting a glass ribbon according to claim 1. Claim 3 When the sensor detects that both end portions in the width direction and the intermediate portion in the width direction of the glass ribbon are present, the pressing member applies the bending stress, and when the sensor detects that at least one of the end portions in the width direction of the glass ribbon is present and the intermediate portion in the width direction of the glass ribbon is absent, the pressing member does not apply the bending stress. The method for cutting a glass ribbon according to claim 2. Claim 4 In the second cutting step, a first cutting process of cutting the glass ribbon with the pressing member applying the bending stress and a second cutting process of cutting the glass ribbon without the pressing member applying the bending stress are performed, and the value of the cutting element in the case of performing the second cutting process is made larger than the value of the cutting element in the case of performing the first cutting process. The method for cutting a glass ribbon according to claim 2 or 3. Claim 5 The cutting blades are respectively installed corresponding to one end and the other end in the width direction of the glass ribbon, and the second cutting device includes a pressing member that applies a bending stress in advance to the pressing area of the glass ribbon when pressing the cutting blades against the glass ribbon. When pressing the cutting blades against the glass ribbon with the pressing member applying the bending stress to the glass ribbon, a time difference is provided between when one cutting blade presses one end in the width direction of the glass ribbon and when the other cutting blade presses the other end in the width direction of the glass ribbon. The method for cutting a glass ribbon according to any one of claims 1 to 4.

6. The time difference is 0.1 to 1.0 seconds. The method for cutting a glass ribbon according to claim 5.

7. Each time cutting is performed using the cutting blades, the holding member is advanced to a holding position where the glass ribbon can be held, and each time cutting using the cutting blades is completed, the holding member is retracted to a retracting position where it does not interfere with the glass ribbon. The method for cutting a glass ribbon according to any one of claims 1 to 6.

8. Within 1 second from the time when cutting using the cutting blades is completed, the holding member is moved from the holding position toward the retracting position. The method for cutting a glass ribbon according to claim 7.

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