Glass plate manufacturing method, glass plate manufacturing apparatus, and glass plate

Abstract

According to the present invention, a cleavage bar 5 is brought into contact with a glass ribbon 2 moving downward in a vertical position, and the glass ribbon 2 is cleaved along a scribe line 3 which extends in the width direction of the glass ribbon 2, so that the glass ribbon 2 is cut into glass sheets 2y. At this time, the glass ribbon 2, which has a width-direction shape that is a curved shape protruding in one side thereof, is cleaved along the scribe line 3 by bringing a contact side end 5a of the cleavage bar 5, which has a width-direction shape that is a curved shape protruding in the same side in which the width-direction shape the glass ribbon 2 protrudes, into contact with the glass ribbon 2.

Description

[Technical field]

[0001] The present invention relates to a method and apparatus for manufacturing a glass sheet, in which a glass ribbon moving downward in a vertical position is bent and split along scribe lines extending in the width direction of the glass ribbon to cut out a glass sheet from the glass ribbon, and the cut out glass sheet. [Background technology]

[0002] As is well known, in the field of glass sheet production, glass sheets are cut out from a glass ribbon that is continuously formed by a down-draw method or the like and moves downward in a vertical position. A specific example of a method and apparatus for producing glass sheets in this manner is disclosed in Patent Document 1.

[0003] The device disclosed in the document includes a scribing means for forming a scribe line on a glass ribbon moving downward in a vertical position, a breaking bar (called a fulcrum bar in the document) that is pressed against a region of the glass ribbon where the scribe line is formed, and a supporting means (called a breaking arm in the document) that supports a portion of the glass ribbon to be cut out that is below the scribe line. The method disclosed in the document for cutting out a glass sheet using this device involves first forming a scribe line along the width direction of the glass ribbon with the scribing means, and then pressing the breaking bar against the region of the glass ribbon where the scribe line is formed. Next, the supporting means that supports the portion of the glass ribbon to be cut out is operated to bend the glass ribbon in the vertical direction with the breaking bar as a fulcrum, thereby breaking the glass ribbon along the scribe line and cutting out a glass sheet from the glass ribbon. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-90446 A Summary of the Invention [Problem to be solved by the invention]

[0005] According to Patent Document 1, with regard to the curvature of the glass ribbon when the glass ribbon is bent and broken along the scribe lines, the glass ribbon is merely curved in the vertical direction. Therefore, the bending and breaking method disclosed in the publication causes the following problems.

[0006] In other words, the supporting means disclosed in the publication supports only both ends of the glass ribbon in the width direction. In such a supporting mode, a portion of the glass ribbon closer to the center in the width direction is not restrained, which leads to a situation in which the glass ribbon is curved in the width direction. This situation becomes more noticeable when the glass ribbon is thin.

[0007] When the glass ribbon is curved in the width direction in this way, if a conventional breaking bar is used to break the glass ribbon, the glass ribbon cannot be properly broken along the scribe lines, which can result in many cracks and breaking errors, leading to a deterioration in the quality of the cut glass sheet and a decrease in product yield.

[0008] In view of the above, an object of the present invention is to improve the quality of cut glass sheets and increase product yield by enabling proper bending and cutting without causing cracks or cutting errors. [Means for solving the problem]

[0009] A first aspect of the present invention devised to solve the above-mentioned problems is a method for manufacturing a glass plate in which a breaking bar is brought into contact with a glass ribbon moving downward in a vertical position, and the glass ribbon is bent and broken along a scribe line extending in its width direction, thereby cutting a glass plate from the glass ribbon, characterized in that the glass ribbon has a curved shape along the width direction that is convex on one side, and the abutting side end of the breaking bar, which has a curved shape along the width direction that is convex on the same side as the glass ribbon, is brought into contact with the glass ribbon, which has a curved shape along the width direction that is convex on the same side as the glass ribbon, to bend and break the glass ribbon along the scribe line.

[0010] According to this method, when breaking a glass ribbon having a curved shape along the width direction that is convex on one side, a breaking bar having an abutting side end portion that has a curved shape along the width direction that is convex on the same side as the glass ribbon is used. Therefore, it is possible to prevent the occurrence of cracks or breaking errors when breaking a glass ribbon curved in the width direction using a breaking bar. As a result, the quality of the cut glass sheet and the product yield are improved.

[0011] In this method, the abutment side end of the breaking bar may be brought into contact with the glass ribbon by butting, with the region of the glass ribbon where the scribe line is formed being curved in the vertical direction.

[0012] In this way, the breaking is completed when the contact side end of the breaking bar abuts against the glass ribbon, which reduces the variation or fluctuation in the time required for breaking and also leads to a reduction in the tact time.

[0013] In this method, when the contact side end of the breaking bar is brought into contact with the glass ribbon by butting, it is preferable that a widthwise central portion of the contact side end is brought into contact prior to other portions.

[0014] In this way, when the contact side end of the breaking bar abuts against the glass ribbon, the crack smoothly extends from the widthwise center of the scribe line toward both widthwise ends, making it possible to perform high-quality breaking. If a portion of the contact side end of the breaking bar that is offset from the widthwise center is abutted against the glass ribbon before other portions, the crack will propagate from a portion other than the widthwise center of the scribe line, preventing smooth crack propagation and causing breakage or cutting errors. According to the method described herein, such problems are unlikely to occur.

[0015] In the above method, the breaking bar may be divided into a plurality of breaking bar members in the width direction, and adjacent breaking bar members may be connected so that the angle between the two members in the width direction is adjustable.

[0016] In this way, the curvature of the curved shape (macroscopic curved shape) along the width direction of the abutting side end portion can be changed by adjusting the angle in the width direction between the adjacent breaking bars. Here, the curved shape along the width direction of the glass ribbon changes depending on the width direction dimension and thickness of the glass ribbon. The curved shape along the width direction of the abutting side end portion can be made to appropriately follow such changes.

[0017] In this method, the split bar may be divided into two split bar members in the width direction, and both members may be connected at a central position in the width direction of the split bar.

[0018] In this way, the curvature of the curved shape along the width direction of the abutting side end of the split bar can be changed with a simple operation. Moreover, since the two split bar members are connected at the center position in the width direction of the split bar, the shape along the width direction of the abutting side end of the split bar can be curved symmetrically on both sides of the center position in the width direction.

[0019] In these methods, the abutting end of the breaking bar may be brought into contact with the glass ribbon so that a pressing force greater than that acting on either side of the width of the glass ribbon is applied to the widthwise center of the glass ribbon, thereby causing a crack to propagate from the widthwise center of the scribe line toward both widthwise ends, thereby breaking the glass ribbon.

[0020] In this way, when the glass ribbon is bent and broken, a relatively large pressing force acts on the widthwise center of the glass ribbon, and a starting point from which a crack will progress is formed in the widthwise center of the scribe line. Therefore, the crack smoothly progresses from the starting point in the widthwise center of the scribe line toward both widthwise ends, thereby performing high-quality bending and breaking.

[0021] A second aspect of the present invention devised to solve the above-mentioned problems is a glass plate manufacturing apparatus configured to cut out a glass plate from a glass ribbon by bringing a breaking bar into contact with a glass ribbon moving downward in a vertical position and breaking the glass ribbon along a scribe line extending in its width direction, characterized in that the glass ribbon has a curved shape along the width direction that is convex on one side, and the abutting side end of the breaking bar, which has a curved shape along the width direction that is convex on the same side as the glass ribbon, is brought into contact with the glass ribbon, which has a curved shape along the width direction that is convex on the same side as the glass ribbon, to break the glass ribbon along the scribe line.

[0022] This makes it possible to obtain the same effects as those of the previously described manufacturing method having substantially the same configuration as this manufacturing apparatus.

[0023] A third aspect of the present invention, which has been devised to solve the above problems, is a rectangular glass sheet having four sides, characterized in that one of the four sides perpendicular to the sheet drawing direction or two parallel sides has a crack origin within a range of 10% of the entire length in the longitudinal direction from a longitudinal center point toward both sides in the longitudinal direction. Here, the crack origin refers to the starting point of a crack.

[0024] According to this configuration, since the crack origin exists within a predetermined range of the longitudinal center of the side of the glass sheet, the crack propagates from the widthwise center of the glass ribbon toward both widthwise ends when the glass ribbon is bent and broken. That is, a crack propagation origin is formed in the widthwise center of the glass ribbon, and the crack smoothly propagates from the origin toward both widthwise ends. Therefore, the glass sheet is properly cleaved, and adhesion of glass powder to the glass sheet due to defective cleavage is prevented, and the glass sheet has high quality. Moreover, according to this glass sheet, since the origin of the crack propagation can be grasped by the crack origin, it is possible to make adjustments such as moving the origin further toward the widthwise center when the glass ribbon is bent and broken. Effect of the Invention

[0025] According to the present invention, even if the glass ribbon is curved in the width direction, it can be properly bent and cut without causing cracks or cutting errors, thereby improving the quality of the cut glass sheets and improving the product yield. [Brief description of the drawings]

[0026] [Figure 1] 1 is a side view showing a schematic configuration of a glass sheet manufacturing apparatus according to an embodiment of the present invention. [Diagram 2] 1 is a front view showing a schematic configuration of a glass plate manufacturing apparatus according to an embodiment of the present invention (a front view seen along the arrow X in FIG. 1). [Diagram 3] 3 is a cross-sectional plan view taken along line YY in FIG. 2. [Figure 4] FIG. 2 is a plan view showing a main part of a breaking bar which is a component of the glass sheet manufacturing apparatus according to the embodiment of the present invention. [Diagram 5] FIG. 2 is a schematic side view showing a state in which the method for producing a glass plate according to the embodiment of the present invention is carried out. [Figure 6] FIG. 2 is a schematic side view showing a state in which the method for producing a glass plate according to the embodiment of the present invention is carried out. [Figure 7] FIG. 2 is a schematic side view showing a state in which the method for producing a glass plate according to the embodiment of the present invention is carried out. [Figure 8] FIG. 2 is a schematic side view showing a state in which the method for producing a glass plate according to the embodiment of the present invention is carried out. [Figure 9] FIG. 1 is a schematic perspective view of a glass plate according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, a method and an apparatus for producing a glass sheet according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0028] FIG. 1 is a side view illustrating a glass sheet manufacturing apparatus according to an embodiment of the present invention, and FIG. 2 is a front view of the manufacturing apparatus as viewed along the arrow X in FIG. 1. As shown in these figures, the manufacturing apparatus 1 includes a scribing means S for forming a scribe line 3 extending in the width direction of a glass ribbon 2 moving downward (in the direction of the arrow Z, also referred to as the sheet drawing direction in this specification) in a vertical position, a support means 4 for supporting a portion to be cut out 2x located below the scribe line 3 in the glass ribbon 2, and a breaking bar 5 that abuts against the glass ribbon 2. Furthermore, the manufacturing apparatus 1 includes a moving means 6 for moving the breaking bar 5 in the horizontal direction toward the glass ribbon 2 and moving it back to a retreat position. Here, the moving means 6 is configured to move the breaking bar 5 to the upper side of the scribe line 3 and abut against it in a state in which a peripheral portion of a formation region 2s of the scribe line 3 (hereinafter referred to as the scribe line formation region 2s) is curved in the vertical direction, as shown by a solid line in FIG. 1, when breaking the glass ribbon 2. The moving means 6 is constituted by an air cylinder in this embodiment, but may be a feed device such as another cylinder or a ball screw mechanism.

[0029] The scribing means S includes a wheel cutter 7 that forms a scribe line 3 while traveling in the width direction (in FIG. 1, a direction perpendicular to the paper surface) on the front surface 2a of the glass ribbon 2 moving in the direction of the arrow Z, and a support rod 8 that is long in the width direction and supports the portion of the glass ribbon 2 along which the wheel cutter 7 travels from the rear surface 2b side. The wheel cutter 7 has a blade (edge) on the periphery that rotates during travel, and is formed in a disk shape. The support rod 8 has an abutment surface that abuts against the portion along which the wheel cutter 7 travels, and protrudes from both ends of the glass ribbon 2 in the width direction.

[0030] The breaking bar 5 abuts against a portion of the back surface 2b of the glass ribbon 2 above the scribe line 3 by butting, and has a contact end portion 5a with a convex (e.g., semicircular or curved) longitudinal cross-sectional side surface that abuts against the back surface 2b of the glass ribbon 2. Here, the portion above the scribe line 3 that the breaking bar 5 abuts against is a portion of the uncurved glass ribbon 2 that is a predetermined distance L1 above the scribe line 3. This predetermined distance L1 is set to 5 mm or more and less than 70 mm. In addition, considering that the glass ribbon 2 has an effective area (area of ​​the product glass sheet), this predetermined distance L1 may be set to 5 mm or more and less than the distance to the lower end of the effective area. In this case, the predetermined distance L1 is set to 5 mm or more and less than 20 mm, taking into consideration the effective area of ​​the glass ribbon 2 in this embodiment. Both ends of the breaking bar 5 in the width direction are located inward in the width direction from both ends of the glass ribbon 2 in the width direction.

[0031] 3 is a cross-sectional plan view cut along line YY in FIG. 2. As shown in the figure, the glass ribbon 2 has a curved shape along the width direction (WW direction) that is convex toward one side (the surface 2a side), and both ends in the width direction are gripped by a pair of claws 11ax of a chuck 11a described later. The contact side end 5a of the folding bar 5 has a curved shape along the width direction that is convex toward the same side as the glass ribbon 2. In this embodiment, the folding bar 5 itself also has a curved shape along the width direction that is convex toward the same side as the glass ribbon 2. Furthermore, the folding bar 5 is divided into two folding bar members 5x and 5y, and these two members 5x and 5y are connected at the center position in the width direction of the folding bar 5. These two members 5x and 5y have bilaterally symmetrical shapes. Therefore, both members 5x and 5y have abutment side ends 5xa and 5ya, respectively, and the abutment side end 5a of the splitting bar 5 described above is formed by connecting these two abutment side ends 5xa and 5ya.

[0032] FIG. 4 is an enlarged plan view of the main part showing the connection part of the two breaking bar members 5x, 5y. As shown in the figure, at the connection part of the two breaking bar members 5x, 5y, the ends 5xb, 5yb on the glass ribbon 2 side are in contact with each other, and the breaking bar 5 is symmetrical in the width direction with the ends 5xb, 5yb as the center. In addition, the gap SP between the opposing end faces 5xc, 5yc of the two breaking bar members 5x, 5y gradually expands toward the opposite side to the glass ribbon 2 side. The two breaking bar members 5x, 5y are connected so that the angle formed by both the breaking bar members 5x, 5y can be adjusted. The angle adjustment mechanism MC for adjusting the angle has a plate PL that is fitted across both the members 5x, 5y and has a long hole HL, and bolts Bx, By that are inserted into the long hole HL of the plate PL and screwed into both the members 5x, 5y. According to this angle adjustment mechanism MC, the bolts Bx and By are loosened, and the angle between the two members 5x and 5y is changed using the contact parts of both ends 5xb and 5yb as fulcrums, and then the bolts Bx and By are tightened to adjust the angle between the two members 5x and 5y. The adjustment of the angle between the two members 5x and 5y is performed every time the curvature of the curved shape of the glass ribbon 2 changes. The angles between the two members 5x and 5y are preferably set at an angle such that the ends (ends on both ends of the glass ribbon 2 in the width direction) of the two breaking bar members 5x and 5y on the opposing sides do not come into contact with the glass ribbon 2. In other words, the angles between the two members 5x and 5y are preferably set at an angle such that a larger pressing force (butting force) acts on the center of the width direction of the glass ribbon 2 than on both sides in the width direction when the two members 5x and 5y come into contact with the glass ribbon 2. In this way, a crack origin, which will be described later, can be formed in the longitudinal center of the cleaved side of the glass plate 2y.

[0033] 1 and 2, the components of the manufacturing apparatus 1 will be described. A suction nozzle 9 that sucks up glass powder generated by bending and breaking is disposed at a position behind the scribe line 3 of the glass ribbon 2. The suction nozzle 9 has an opening 9a that faces the surface 2a of the glass ribbon 2, and sucks up the glass powder through the opening 9a by the operation of a negative pressure generating device (not shown) such as a negative pressure pump.

[0034] The support means 4 includes an arm 10 extending along the longitudinal direction of the glass ribbon 2, and a chuck group 11 consisting of a plurality of chucks 11a (five in this embodiment) attached to the arm 10 at intervals from each other. The arm 10 and the chuck group 11 are disposed on one side and the other side in the width direction of the glass ribbon 2. Each of the plurality of chucks 11a includes a pair of claws 11ax that grip the portion 2x to be cut out of the glass ribbon 2 in the thickness direction.

[0035] Furthermore, the support means 4 is configured to change its posture from a basic posture shown by a chain line in FIG. 1 to an inclined posture shown by a solid line in the same figure while supporting the to-be-cut portion 2x. This change in posture of the support means 4 is achieved by a rotational movement of the support means 4 centered around the vicinity of the position of the scribing bar 5 (the position shown by the solid line in FIG. 1). Furthermore, the change in posture of the support means 4 is achieved while moving downward at the same speed as the glass ribbon 2. Then, the support means 4 curves the peripheral portion of the scribe line formation region 2s in the glass ribbon 2 in the vertical direction so that the front surface 2a side becomes convex by the above-mentioned rotational movement. Such a rotational movement of the support means 4 is performed in a timed manner with the movement of the moving means 6 to move the scribing bar 5 toward the glass ribbon 2. Then, the moving means 6 is configured to abut the scribing bar 5 against the glass ribbon 2 at the same time as the rotational movement of the support means 4 is completed. Specifically, the moving means 6 is configured to bring the breaking bar 5 into contact with the glass ribbon 2 within one second before or after the completion of the rotation operation of the supporting means 4, thereby completing the operation of curving the glass ribbon 2. In this embodiment, the moving means 6 is configured to bring the breaking bar 5 into contact with the glass ribbon 2 just before the completion of the rotation operation of the supporting means 4, that is, before that time and within one second of that time. While the supporting means 4 is supporting the portion to be cut 2x, as shown in Fig. 3, the glass ribbon 2 is curved in the width direction so that the front surface 2a side is convex.

[0036] In this embodiment, the arm 10 and the chuck group 11 arranged on one side in the width direction of the glass ribbon 2, and the arm 10 and the chuck group 11 arranged on the other side in the width direction of the glass ribbon 2 are configured to rotate as a unit. However, the arms 10 and the chuck groups 11 on both sides may each rotate individually.

[0037] Among the components of the manufacturing apparatus 1, the breaking bar 5 and the support rod 8 are mounted on a first housing (not shown) arranged on the back surface 2b side of the glass ribbon 2, and the wheel cutter 7 and the suction nozzle 9 are mounted on a second housing (not shown) arranged on the front surface 2a side of the glass ribbon 2. The first housing and the second housing are each capable of moving in the vertical direction. As a result, the breaking bar 5 and the support rod 8 are configured to move vertically together with the first housing while maintaining their relative positional relationship in the vertical direction. In addition, the wheel cutter 7 and the suction nozzle 9 are configured to move vertically together with the second housing while maintaining their relative positional relationship in the vertical direction.

[0038] Each of the first housing and the second housing can move downward following the glass ribbon 2 at the same speed as the downward movement speed of the glass ribbon 2. As a result, each of the breaking bar 5, the support rod 8, the wheel cutter 7, and the suction nozzle 9 is configured to move downward at the same speed as the downward movement speed of the glass ribbon 2 along with the downward movement of the first housing and the second housing following the glass ribbon 2, thereby performing its own function. Similarly, the support means 4 is also configured to move downward at the same speed as the movement speed of the glass ribbon 2, while performing its own function. Therefore, when each of the above-mentioned components of the manufacturing apparatus 1 performs its own function, the relative speed in the vertical direction with respect to the glass ribbon 2 is zero.

[0039] Of the above components, the breaking bar 5, the support rod 8, the wheel cutter 7, and the suction nozzle 9 are configured to move along the thickness direction of the glass ribbon 2 between an operating position for performing their own functions and a retracted position for retracting away from the glass ribbon 2, as shown by the arrows in Fig. 1. The movement of each of these components along the thickness direction is performed while moving downward at the same speed as the glass ribbon 2. The positions of the breaking bar 5, the wheel cutter 7, the support rod 8, and the suction nozzle 9 shown by the solid lines in Fig. 1 are operating positions, and the positions shown by the dashed lines in the same figure are retracted positions.

[0040] A restricting roller 12 is disposed above the scribing means S on the front surface 2a side of the glass ribbon 2, and serves as a fulcrum when the glass ribbon 2 is curved by the rotational operation of the supporting means 4. When the glass ribbon 2 is bent and broken, tension is applied to the glass ribbon 2 (the peripheral portion of the scribe line formation region 2s) between the supporting means 4 and the restricting roller 12. Therefore, when the breaking bar 5 hits the glass ribbon 2, tension is applied to the abutting portion of the glass ribbon 2.

[0041] Next, a method for producing a glass plate using the above-mentioned production apparatus 1 will be described with reference to FIGS.

[0042] In the method for manufacturing a glass sheet according to the present embodiment, the glass ribbon 2 to be broken is formed, for example, by a down-draw method (such as an overflow down-draw method). The glass ribbon 2 is formed to a thickness of, for example, 1000 μm or less (preferably 700 μm or less and 100 μm or more), and has flexibility that allows it to be curved by the action of an external force.

[0043] The method for manufacturing a glass plate according to this embodiment broadly comprises a scribing process for forming a scribe line 3 in a glass ribbon 2, and a bending and splitting process for bending and splitting the glass ribbon 2 along the scribe line 3 formed in the scribing process to cut out a glass plate.

[0044] 5, in the scribing step, first, the wheel cutter 7 and the support rod 8 are moved from the retracted position to the operating position while the multiple chucks 11a of the support means 4 support the portion to be cut out 2x. Next, the wheel cutter 7 that has been moved to the operating position is caused to run on the surface 2a of the glass ribbon 2 in the width direction to form a scribe line 3.

[0045] After the scribing step is completed as described above, the wheel cutter 7 and the support rod 8 are moved from the operating position to the retreated position. In this case, the multiple chucks 11a of the support means 4 continue to support the to-be-cut-out portion 2x even after the scribing step is completed. Here, when the scribing step is completed, the wheel cutter 7 and the support rod 8 are in a state of being at the same height position as the scribe line 3. From this state, in preparation for performing the bending step, both the first housing and the second housing move upward relative to the glass ribbon 2. As a result, as shown in FIG. 6, the bending bar 5 is held at a height position a predetermined distance L1 above the scribe line 3, and the suction nozzle 9 is held at the same height position as the scribe line 3.

[0046] In the folding step, as shown in FIG. 7, the supporting means 4 is rotated in the direction indicated by the arrow C while the folding bar 5 and the suction nozzle 9 are held in the retracted position. As a result, the posture of the supporting means 4 starts to change from the basic posture to an inclined posture, and the peripheral portion of the scribe line formation region 2s of the glass ribbon 2 starts to curve so that the front surface 2a side becomes convex. At this time, the portion of the glass ribbon 2 above the scribe line formation region 2s is supported by the regulating roller 12, so that tension is applied to the peripheral portion of the scribe line formation region 2s. During this rotational operation of the supporting means 4, the moving means 6 moves the folding bar 5 in the horizontal direction toward the glass ribbon 2. In the same manner, the suction nozzle 9 also moves toward the glass ribbon 2. Then, at the time when the angle α of the supporting means 4 with respect to the vertical line reaches a preset inclination angle, that is, immediately before the rotational operation of the supporting means 4 is completed, the moving means 6 causes the contact side end 5a of the folding bar 5 to abut against the back surface 2b of the glass ribbon 2. In this case, the portion where the abutting side end 5a of the breaking bar 5 abuts against the back surface 2b of the glass ribbon 2 is a portion that is a predetermined distance L1 (strictly speaking, the predetermined distance L1 shown in FIG. 6) away from the scribe line 3 on the upper side. The state when the abutting side end 5a of the breaking bar 5 abuts against the glass ribbon 2 is the state shown by the solid line in FIG. 1 in a side view, and the state shown in FIG. 3 in a plan view. In this case, the widthwise center portion of the abutting side end 5a of the breaking bar 5 abuts against the back surface 2b of the glass ribbon 2 before other portions (such as the peripheries of both ends in the width direction). Therefore, when the abutting side end 5a of the breaking bar 5 abuts against the back surface 2b of the glass ribbon 2, a pressing force (abutting force) larger than that on both sides in the width direction acts on the widthwise center portion of the glass ribbon 2. As a result, a starting point for the propagation of a crack is formed in the widthwise center portion of the scribe line 3, and the crack smoothly propagates from this starting point toward both ends in the width direction of the scribe line 3.

[0047] By such an operation, the glass ribbon 2 is broken along the scribe line 3, and the portion to be cut out 2x is cut out as a glass plate 2y. Immediately after this breaking is performed, as shown in Fig. 8, the broken end surface 2z at the lower end of the glass ribbon 2 and the broken end surface 2yz at the upper end of the glass plate 2y are separated from each other and do not come into contact with each other, and the breaking bar 5 does not come into contact with either 2(2z) or 2y(2yz). Glass powder generated by this breaking is sucked up by the suction nozzle 9.

[0048] FIG. 9 is a perspective view showing a rectangular glass plate 2y cut out by such an operation. As shown in the figure, a crack origin D formed by contacting one side 2z of the four sides of the glass plate 2y (specifically, the ends 5xb, 5yb) with the breaking bar 5 (specifically, the ends 5xb, 5yb) exists. In detail, the crack origin D is formed on one end face 2z perpendicular to the Z direction, which is the sheet drawing direction, or on two parallel end faces 2z of the four end faces of the glass plate 2y. In the illustrated example, the crack origin D exists only on one side (one end face) 2z, but a similar crack origin may also exist on an edge (end face) parallel to the side. In this embodiment, the crack origin D is formed on the end face 2z of one of the front and back faces of the glass plate 2y, with one face 2y1 as one end, and does not reach the other face 2y2 of the glass plate 2y. The one face 2y1 corresponds to the back face of the glass ribbon 2. The crack origin D is present within a range (K) of 10% (Ly) of the total length (Lx) in the longitudinal direction from the longitudinal center point (j) of the end face 2z on both sides in the longitudinal direction. The crack origin D can be identified or estimated by a method of confirming with an electron microscope, or, if it cannot be confirmed with an electron microscope, by a method of estimating from rib marks or Wallner lines generated on the glass plate 2y.

[0049] The sheet drawing direction can be confirmed by a known method, for example, by checking the direction of linear projections and recesses formed on the surface of the glass sheet 2y.

[0050] According to this embodiment in which folding and dividing is performed as described above, the following advantageous effects can be obtained.

[0051] In this embodiment, when bending and breaking the glass ribbon 2 having a curved shape along the width direction that is convex on one side, a bending and breaking bar 5 having a contact side end 5a having a curved shape along the width direction that is convex on the same side as the glass ribbon 2 is used. Therefore, it is possible to prevent the occurrence of cracks and breaking errors when bending and breaking the glass ribbon 2 curved in the width direction using the bending and breaking bar 5. As a result, the quality of the cut glass plate 2y and the product yield are improved.

[0052] In this embodiment, the contact side end 5a of the breaking bar 5 is abutted against the glass ribbon 2 in a state in which the peripheral portion of the scribe line formation region 2s in the glass ribbon 2 is curved in the vertical direction, so that breaking is completed at the point in time when the abutment is reached. This reduces the variation or fluctuation in the time required for breaking, and also leads to a reduction in the tact time.

[0053] In this embodiment, when the contact side end 5a of the breaking bar 5 is brought into contact with the glass ribbon 2, the widthwise central portion of the contact side end 5a is brought into contact with the glass ribbon 2 before other portions, so that at the time of contact, a crack smoothly extends from the widthwise central portion of the scribe line 3 toward both widthwise ends. This makes it possible to perform high-quality breaking.

[0054] In this embodiment, the breaking bar 5 is divided into two breaking bar members 5x and 5y in the width direction. The members 5x and 5y are connected so that the angle between them in the width direction can be adjusted, and therefore the curvature of the curved shape (macroscopic curved shape) of the abutting side end 5a of the breaking bar 5 along the width direction can be changed. Here, the curved shape along the width direction of the glass ribbon 2 changes depending on the width dimension and thickness of the glass ribbon 2. The curved shape along the width direction of the abutting side end 5a can be made to appropriately follow such changes.

[0055] In this embodiment, the two split bar members 5x, 5y are connected at the widthwise center of the split bar 5, so that the curvature of the curved shape of the abutting end 5a along the widthwise direction can be changed by a simple operation. Moreover, the shape of the abutting end 5a along the widthwise direction can be made symmetrical on both sides of the widthwise center.

[0056] Although the method for manufacturing a glass plate according to the embodiment of the present invention has been described above, the present invention is not limited thereto, and various variations are possible without departing from the gist of the present invention.

[0057] In the above embodiment, the abutment side end 5a of the breaking bar 5 is abutted against a portion of the glass ribbon 2 above the scribe line 3, but it may also be abutted against a portion of the glass ribbon 2 at the same height as the scribe line 3.

[0058] In the above embodiment, the abutment side end 5a of the breaking bar 5 is abutted against the glass ribbon 2 in a state in which the glass ribbon 2 is curved in the vertical direction, but the glass ribbon 2 may be curved in the vertical direction and broken after the abutment side end 5a of the breaking bar 5 is brought into contact with the glass ribbon 2. In this case, the abutment side end 5a of the breaking bar 5 is not abutted against the glass ribbon 2, but a pressing force acts on the glass ribbon 2 from the abutment side end 5a of the breaking bar 5 in the same manner as in the case in which the abutment operation is performed.

[0059] In the above embodiment, the shape of the breaking bar 5 itself along the width direction is a curved shape that is convex on the same side as the glass ribbon 2, but the shape of the breaking bar 5 itself may be another shape as long as the shape of the contacting side end 5a along the width direction is a curved shape that is convex on the same side as the glass ribbon 2. In addition, as long as the shape of the majority of the contacting side end 5a along the width direction is a curved shape that is convex on the same side as the glass ribbon 2, a part of it may be a curved shape that is convex on the opposite side to the glass ribbon 2.

[0060] In the above embodiment, the support means 4 supports the portion 2x of the glass ribbon 2 to be cut out by a pair of claws 11ax of the chuck 11a, but instead, the portion 2x to be cut out may be supported by an adsorption pad that adsorbs the front or back surface of the portion 2x to be cut out.

[0061] In the above embodiment, bending is performed by bending the peripheral portion of the scribe line formation region 2s of the glass ribbon 2, but even if only the scribe line formation region 2s is curved, in other words, by curving at least the scribe line formation region 2s, bending can be performed in a similar manner. [Explanation of symbols]

[0062] 1. Glass plate manufacturing equipment 2. Glass ribbon 2a Surface of the glass ribbon 2b Back side of glass ribbon 2s Scribe line formation area (Scribe line formation area) 2x Cutting section 2y Glass plate 2z Edge of glass plate (edge ​​face) 3 Scribe line 4 Support means 5 Break bar 5a Abutment end of the split bar 5x Break bar material 5y Broken bar material 6. Transportation D Crack Origin S Scribe means MC angle adjustment mechanism

Claims

1. A method for manufacturing a glass sheet, comprising the steps of: bringing a breaking bar into contact with a glass ribbon moving downward in a vertical position, and breaking the glass ribbon along a scribe line extending in a width direction thereof, thereby cutting a glass sheet from the glass ribbon, When the abutment side end of the breaking bar, which has a curved shape along the width direction that is convex on the same side as the glass ribbon, is brought into contact with the glass ribbon, which has a curved shape along the width direction that is convex on one side, In a state where the region in the glass ribbon where the scribe line is formed is curved in the vertical direction, the breaking bar that is separated from the glass ribbon is moved toward the glass ribbon, thereby bringing the abutment side end of the breaking bar into contact with the glass ribbon by butting; At the time of contact, the glass ribbon is bent and broken along the scribe lines.

2. A method for manufacturing a glass sheet, comprising the steps of: bringing a breaking bar into contact with a glass ribbon moving downward in a vertical position, and breaking the glass ribbon along a scribe line extending in a width direction thereof, thereby cutting a glass sheet from the glass ribbon, When the abutment side end of the breaking bar, which has a curved shape along the width direction that is convex on the same side as the glass ribbon, is brought into contact with the glass ribbon, which has a curved shape along the width direction that is convex on one side, In a state where the region in the glass ribbon where the scribe line is formed is curved in the vertical direction, the abutment side end of the breaking bar is brought into contact with the glass ribbon by butting, When the abutment side end of the breaking bar is brought into contact with the glass ribbon by butting, the width direction central portion of the abutment side end is brought into contact with the glass ribbon prior to other portions, A method for manufacturing a glass plate, comprising bending and breaking the glass ribbon along the scribe lines.

3. A method for manufacturing a glass sheet, comprising the steps of: bringing a breaking bar into contact with a glass ribbon moving downward in a vertical position, and breaking the glass ribbon along a scribe line extending in a width direction thereof, thereby cutting a glass sheet from the glass ribbon, The glass ribbon has a curved shape along the width direction that is convex on one side, and the abutment side end of the breaking bar, which has a curved shape along the width direction that is convex on the same side as the glass ribbon, is brought into contact with the glass ribbon, thereby breaking the glass ribbon along the scribe line, and A method for manufacturing a glass plate, characterized in that the bending bar is divided into a plurality of bending bar members in the width direction, and adjacent bending bar members are connected so that the angle between the two members in the width direction can be adjusted.

4. 4. The method for manufacturing a glass plate according to claim 3, wherein the breaking bar is divided into two breaking bar members in the width direction, and both members are connected at a central position in the width direction of the breaking bar.

5. A method for manufacturing a glass sheet, comprising the steps of: bringing a breaking bar into contact with a glass ribbon moving downward in a vertical position, and breaking the glass ribbon along a scribe line extending in a width direction thereof, thereby cutting a glass sheet from the glass ribbon, When the abutment side end of the breaking bar, which has a curved shape along the width direction that is convex on the same side as the glass ribbon, is brought into contact with the glass ribbon, which has a curved shape along the width direction that is convex on one side, a contact side end of the breaking bar being brought into contact with the glass ribbon so that a pressing force greater than that acting on either side of the width direction of the glass ribbon is applied to the width direction center of the glass ribbon, thereby causing a crack to propagate from the width direction center of the scribe line toward both width direction ends, thereby breaking the glass ribbon along the scribe line.

6. A glass sheet manufacturing apparatus configured to cut out a glass sheet from a glass ribbon by contacting a breaking bar with a glass ribbon moving downward in a vertical position and breaking the glass ribbon along a scribe line extending in a width direction of the glass ribbon, a contact side end of the breaking bar, the shape of which along the width direction is a curved shape that is convex on the same side as the glass ribbon, is brought into contact with the glass ribbon, the shape of which along the width direction is a curved shape that is convex on one side, to break the glass ribbon along the scribe line; A glass plate manufacturing apparatus characterized in that the bending bar is divided into a plurality of bending bar members in the width direction, and adjacent bending bar members are connected so that the angle between the two members in the width direction can be adjusted.

7. A glass sheet manufacturing apparatus configured to cut out a glass sheet from a glass ribbon by contacting a breaking bar with a glass ribbon moving downward in a vertical position and breaking the glass ribbon along a scribe line extending in a width direction of the glass ribbon, When the abutment side end of the breaking bar, which has a curved shape along the width direction that is convex on the same side as the glass ribbon, is brought into contact with the glass ribbon, which has a curved shape along the width direction that is convex on one side, a contact side end of the breaking bar is brought into contact with the glass ribbon so that a pressing force greater than that on either side of the width direction acts on the width direction center of the glass ribbon, thereby causing a crack to propagate from the width direction center of the scribe line toward both width direction ends, thereby breaking the glass ribbon along the scribe line.

8. A rectangular glass plate having four sides, a glass plate having a crack origin within a range of 10% of the total length in the longitudinal direction from a center point in the longitudinal direction of two sides, including one side of the four sides perpendicular to the sheet drawing direction, or another side parallel to the one side, toward both sides in the longitudinal direction.

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