JP4984866B2 - Method and apparatus for bending glass plate - Google Patents

Description

  The present invention relates to a glass sheet bending method including a heating step of heat-softening a glass plate and a bending step of bending the heat-softened glass plate into a predetermined shape.

Conventionally, the suction mold is divided into a plurality of suction chambers in a method of bending the glass plate heated to near the softening point into a shape that follows the surface shape of the mold by sucking it onto the surface of the suction mold. A glass plate bending method characterized by gradually forming a glass plate from a specific portion by shifting the suction timing in these suction chambers is known (for example, Patent Documents). 1).
JP-A-6-256030

  However, if the suction timing is shifted as in the prior art described above, the time from the start of suction by the first suction chamber to the end of suction by the last suction chamber becomes longer. There is a possibility that the time during which the suction pressure acts on the portion of the glass plate that is formed by suction becomes longer than necessary, and surface roughness occurs in the portion.

  Therefore, an object of the present invention is to provide a glass sheet bending method and a bending apparatus that can appropriately prevent surface roughness of the glass sheet due to suction.

In order to solve the above object, the first invention provides:
In a method for bending a glass plate, comprising a heating step for heat-softening the glass plate, and a bending step for bending the heat-softened glass plate into a predetermined shape,
The bending process includes
Pressing the heat-softened glass plate, the edge of which is supported by the support frame, against the molding surface of the molding mold facing the support frame;
A suction molding step of supplying a negative pressure through a plurality of suction holes formed in the molding surface so that the shape of the pressed glass plate is along the molding surface of the molding mold,
The suction molding step divides the plurality of suction holes into at least two groups, lowers the increased negative pressure with a time difference for each group, and the negative pressure related to the group in which the negative pressure is reduced first is Finally to the negative pressure is lowered according to the group a negative pressure is lowered, is maintained at a predetermined negative pressure range, characterized that you sucking and holding the glass plate.

2nd invention is the bending method of the glass plate which concerns on 1st invention,
The negative pressure related to the group in which the negative pressure has been lowered first is a pressure (Ph) that can be adsorbed and held without causing surface roughness of the glass plate .

3rd invention is the bending method of the glass plate which concerns on 1st invention,
The plurality of suction holes are composed of at least two groups of a central group on the molding surface of the molding mold and a peripheral group surrounding the central group.
Finally, the group in which the negative pressure is lowered is the group of the peripheral portion,
The negative pressure related to the group in which the negative pressure has been lowered first is in a predetermined negative pressure range in which the surface roughness of the glass plate does not occur until the negative pressure in the peripheral edge group is reduced to the predetermined negative pressure. It is maintained and is then released to atmospheric pressure.
4th invention is the bending method of the glass plate which concerns on 3rd invention,
The negative pressure of the group of the peripheral portions is a predetermined negative pressure (Pg) determined by the weight of the glass plate or the like.

The fifth invention is:
In a glass plate bending apparatus for bending a glass sheet heated and softened in a heating furnace into a predetermined shape,
A support frame that supports an edge of the heat-softened glass plate;
A molding mold having a plurality of suction holes formed on the molding surface;
A plurality of suction chambers provided behind the molding surface of the molding mold and communicating with any of the plurality of suction holes of the molding mold;
A negative pressure supply circuit connected to the plurality of suction chambers and supplying negative pressure to the plurality of suction chambers;
A controller for controlling the negative pressure in the plurality of suction chambers for each suction chamber;
A mechanism for changing the position of the molding mold relative to the support frame so that the glass plate supported by the support frame is pressed against the molding surface of the molding mold;
The negative pressure supply circuit has a first negative pressure supply path for supplying a high negative pressure and a second negative pressure supply path for supplying a low negative pressure,
The controller controls the opening / closing valve of the first negative pressure supply path and the opening / closing valve of the second negative pressure supply path, so that the shape of the pressed glass plate is formed into the molding mold. with increasing the negative pressure of the plurality of suction chambers along the surface, is lowered with a time difference for each suction chamber negative pressure is the increased negative pressure in accordance with the group negative pressure above was drop Finally, the glass plate is sucked and held in a predetermined negative pressure range until the negative pressure related to the group where the negative pressure is lowered is lowered .

A sixth invention is a glass sheet bending apparatus according to the fifth invention,
The negative pressure related to the group in which the negative pressure has been lowered first is a pressure (Ph) that can be adsorbed and held without causing surface roughness of the glass plate.

7th invention is the bending forming apparatus of the glass plate which concerns on 5th invention,
The plurality of suction chambers comprises at least two suction chambers, a suction chamber at a central portion on a molding surface of the molding mold and a suction chamber at a peripheral portion surrounding the suction chamber at the central portion,
Each of the plurality of suction chambers is connected to an atmospheric pressure release path,
The controller controls the open / close valve of the first negative pressure supply path, the open / close valve of the second negative pressure supply path, and the open / close valve of the atmospheric pressure release path, thereby controlling the inside of the suction chamber at the peripheral portion. Lastly, the negative pressure is lowered, and the negative pressure in the suction chamber where the negative pressure has been dropped first becomes rough until the negative pressure in the suction chamber at the peripheral edge is lowered to the predetermined negative pressure. and maintaining a negative pressure range not, then the negative pressure in the destination is open to the atmospheric air negative pressure in the suction chamber is lowered.

  According to the first invention, the plurality of suction holes can be divided into at least two groups, the negative pressure can be lowered at an appropriate timing for each group, and the surface roughness of the glass plate can be appropriately prevented. .

  According to 2nd invention, the negative pressure which concerns on the group by which the negative pressure was fallen can be maintained in a suitable negative pressure range, and the surface roughness of a glass plate can be prevented appropriately.

  According to the third invention, the glass plate is held in the molding mold by the negative pressure related to the group of the peripheral portion, and the surface of the glass plate is roughened by releasing the plurality of suction holes of the group of the central portion to atmospheric pressure. It can be prevented appropriately. Furthermore, it is preferable that the group of peripheral parts is provided corresponding to the area | region in which the black ceramic paste layer of the glass plate was formed. In the region where the black ceramic paste layer is formed, since the surface roughness of the glass plate is less conspicuous than the visible region in the central portion of the glass plate, the negative pressure of the peripheral group is made larger than the negative pressure of the central group. be able to. Therefore, when the glass plate is held by the molding mold, the negative pressure acting on the visible region of the glass plate can be further reduced, and the surface roughness of the glass plate can be appropriately prevented.

According to the fifth invention, similarly to the first invention, the increased negative pressure in the suction chamber can be lowered at an appropriate timing for each suction chamber, and the surface roughness of the glass plate is appropriately prevented. be able to.

According to the sixth invention, similarly to the second invention, the inside of the suction chamber in which the negative pressure is lowered can be maintained in an appropriate negative pressure range, and the surface roughness of the glass plate can be appropriately prevented. .

According to the seventh invention, similarly to the third invention, the glass plate is held in the molding mold by the negative pressure in the suction chamber at the peripheral portion, and the plurality of suction holes in the suction chamber in the central portion are opened to atmospheric pressure. Thus, the surface roughness of the glass plate can be appropriately prevented. Further, it is preferable to provide a suction chamber at the peripheral portion corresponding to the region where the black ceramic paste layer of the glass plate is formed. In the area where the black ceramic paste layer is formed, the surface roughness of the glass plate is less conspicuous than the visible area in the central portion of the glass plate, so the negative pressure in the suction chamber in the peripheral portion is lower than the negative pressure in the suction chamber in the central portion. The pressure can be increased. For this reason, when the glass plate is held in the molding mold, the negative pressure acting on the visible region of the glass plate can be further reduced, and the surface roughness of the glass plate can be appropriately prevented.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 schematically shows an example of a main line portion including a glass sheet bending apparatus 10 according to the present invention. As shown in FIG. 1, a flat glass plate G cut into a predetermined size and shape is conveyed to a forming furnace 16 by a roller conveyor 28 while being kept heated and softened in the heating furnace 14. It will be. The glass plate G is positioned while being sucked and held by the flat mold 35 and is carried into the molding furnace 16.

  In the molding furnace 16, the support frame 60 is waiting at the receiving position, and when the glass plate G is positioned above it, the movement of the flat mold 35 is stopped and the suction holding is released, and the glass plate G is supported by the support frame. 60. Thereafter, when the support frame 60 moves to a position directly below the molding mold 70, the molding mold 70 moves downward, and the glass plate G is pressed by the support frame 60 and the molding mold 70, and has a predetermined bent shape. To be molded. Details of the molding method will be described later. The formed glass sheet G is carried out of the forming furnace 16 by, for example, a quench ring (not shown), and is cooled and strengthened to become tempered glass. The flat mold 35 may have a length extending from the downstream side of the roller conveyor 28 to the receiving position of the support frame 60. In this case, the flat mold 35 does not need to move.

  FIG. 2 shows an embodiment of the components of the glass sheet bending apparatus 10 installed in the molding furnace 16. The glass plate bending apparatus 10 of this embodiment includes the support frame 60 and the molding mold 70 described above.

  The support frame 60 is formed in a shape along the outline of the glass plate G so as to support the peripheral edge (the end surface or the vicinity of the end surface) of the glass plate G. That is, the support frame 60 has a support surface 65 that supports the edge of the glass plate G, and the support surface 65 has a shape in which the molding surface 73 of the molding mold 70 is substantially inverted. The support frame 60 may support the entire circumference of the glass plate, or may support a part of the entire circumference. Moreover, the support frame 60 is installed on the upper part of the shuttle 66 comprised with steel materials. The legs of the shuttle 66 extend to a lower portion of the hearth 68 through a slit (not shown) provided in the hearth 68 and are supported by the rail 69 so as to be movable in the X direction.

  The molding mold 70 is supported on the ceiling portion of the molding furnace 16 so as to be movable up and down through lifting means (not shown) (for example, a hydraulic cylinder). The molding surface 73 of the molding mold 70 is made so that the planar size thereof corresponds to substantially the entire surface of the glass plate G. In addition, as shown in FIG. 2, a plurality of suction holes 74 are densely formed over substantially the entire molding surface 73 having a curved longitudinal section.

  The molding surface 73 of the molding mold 70 is covered with a cloth 75 (surface material such as a metal cloth or glass cloth) over substantially the entire surface. The cross 75 is locked to the side portion of the molding mold 70 by a hook or the like, for example. The cloth 75 covers the suction hole 74, thereby preventing the suction hole 74 from being transferred to the surface of the glass plate G during suction and increasing the utilization efficiency of the negative pressure source. Further, the cloth 75 may be held by a negative pressure so as to fit the molding surface 73.

  The suction chamber 80 of the molding mold 70 is divided into a plurality of suction chambers (in this example, three suction chambers 80a, 80b, and 80c). The plurality of suction chambers 80a, 80b, and 80c are set behind the molding surface 73 so as to cover substantially the entire molding surface 73 of the molding mold 70, and each chamber is completely hermetically sealed by walls or the like. It is partitioned so as to be secured.

  The plurality of suction chambers 80 a, 80 b, and 80 c communicate with any one of the plurality of suction holes 74. In the embodiment shown in FIG. 2, the suction chamber 80b is assigned to the region of the molding surface 73 that performs the deepest drawing, and the suction chambers 80a and 80c are assigned to the regions of the molding surface 73 on both sides thereof. ing. Accordingly, each of the suction chambers 80a, 80b, and 80c communicates with the suction hole 74 in the region of the assigned molding surface 73. In the following description, for convenience of explanation, reference numerals 73a, 73b, and 73c (see FIG. 4) are assigned to the regions of the molding surface 73 assigned to the suction chambers 80a, 80b, and 80c, respectively. Reference numerals 74a, 74b, and 74c are assigned to the suction holes 74 of the groups assigned to 80b and 80c, respectively.

  A chamber pressure control device 100 installed outside the molding furnace 16 is connected to each of the suction chambers 80a, 80b, and 80c via pipes (ducts) 82a, 82b, and 82c.

  FIG. 3 is a circuit diagram showing a main configuration of the chamber pressure control apparatus 100 (components of the glass sheet bending apparatus 10 installed outside the molding furnace 16). The chamber pressure control device 100 includes a vacuum source (negative pressure source) 110 and a blow source 120.

  The vacuum source (negative pressure source) 110 includes a vacuum pump and a receiver tank, and the receiver tank holds a negative pressure adjusted to a predetermined pressure (for example, −8000 mmAq). The blow source 120 includes a compressor and a receiver tank, and a positive pressure adjusted to a predetermined pressure (for example, 2000 mmAq) is held in the receiver tank. Here, the negative pressure and the positive pressure are based on the atmospheric pressure, and in this specification and the appended claims, a high negative pressure means a large absolute value. Therefore, “increasing the negative pressure” means increasing the absolute value of the negative pressure, and “decreasing the negative pressure” means decreasing the absolute value of the negative pressure. .

  The negative pressure from the vacuum source 110 is independently supplied to each of the suction chambers 80a, 80b, 80c (pipes 82a, 82b, 82c). That is, the negative pressure supply path from the vacuum source 110 is branched into three and connected to the suction chambers 80a, 80b, and 80c separately.

  Similarly, the positive pressure from the blow source 120 is supplied independently to each of the suction chambers 80a, 80b, 80c (pipes 82a, 82b, 82c). That is, the positive pressure supply path 130 from the blow source 120 branches into three positive pressure supply paths 130a, 130b, and 130c, and is separately connected to the suction chambers 80a, 80b, and 80c. Each positive pressure supply path 130a, 130b, 130c is provided with an open / close valve (damper) 136a, 136b, 136c for controlling the communication state with each suction chamber 80a, 80b, 80c.

  In this embodiment, two negative pressure supply paths, that is, a first negative pressure supply path 140 and a second negative pressure supply path 150 are set for each of the suction chambers 80a, 80b, and 80c. Although described in detail later, the first negative pressure supply path 140 is a system for supplying a relatively high negative pressure necessary for molding by suction of the glass plate G, and the second negative pressure supply path 150 is a glass plate G. This is a system for supplying a relatively low negative pressure so that the surface roughness of the surface does not occur.

  Specifically, the first negative pressure supply path 140 is connected from the vacuum source 110 to the suction chamber 80 via the regulator 142, the buffer tank 144, and the on-off valve (damper) 146. That is, the first negative pressure supply path 140a for the suction chamber 80a is connected from the vacuum source 110 to the pipe 82a via the regulator 142a, the buffer tank 144a, and the on-off valve 146a. Similarly, the first negative pressure supply path 140b for the suction chamber 80b is connected to the pipe 82b from the vacuum source 110 via the regulator 142b, the buffer tank 144b, and the on-off valve 146b. Similarly, the first negative pressure supply path 140c for the suction chamber 80c is connected to the pipe 82c from the vacuum source 110 via the regulator 142c, the buffer tank 144c, and the on-off valve 146c. The negative pressure held in each buffer tank 144a, 144b, 144c is adjusted to a negative pressure (for example, −1500 to −2500 mmAq) for suction molding described later by the corresponding regulator 142a, 142b, 142c. As is apparent from FIG. 3, the magnitudes of the negative pressures held in the buffer tanks 144a, 144b, 144c can be freely adjusted by the regulators 142a, 142b, 142c in an independent relationship. .

  The second negative pressure supply path 150 is connected to the suction chamber 80 from the vacuum source 110 via a regulator 152 and an on-off valve (damper) 156. That is, the second negative pressure supply path 150a for the suction chamber 80a is connected from the vacuum source 110 to the pipe 82a via the regulator 152a and the on-off valve 156a. Similarly, the second negative pressure supply path 150b for the suction chamber 80b is connected to the pipe 82b from the vacuum source 110 via the regulator 152b and the on-off valve 156b. Similarly, the second negative pressure supply path 150c for the suction chamber 80c is connected to the pipe 82c from the vacuum source 110 via the regulator 152c and the on-off valve 156c.

  In this way, in the present embodiment, the two systems of negative pressure supply paths 140 and 150 and the positive pressure supply path 130 can selectively communicate with each of the suction chambers 80a, 80b, and 80c. Selection of the supply path connected to each suction chamber 80a, 80b, 80c is realized by opening / closing control of each on-off valve 136, 146, 156 set on the most downstream side of each supply path. The controller 190 implements the open / close control of each of the open / close valves 136, 146, 156 (that is, the selection of the supply path) and the pressure regulation control of the regulators 142, 152.

  As shown in FIG. 3, the controller 190 includes pressure sensors provided in the buffer tanks 144a, 144b, and 144c, pressures of the suction chambers 80a, 80b, and 80c (in this example, pipes 82a, 82b, and 82c). Pressure sensors 192a, 192b, 192c for measuring (pressure) are connected.

  The controller 190 is also connected to a line control PLC (programmable logic controller) (not shown), which is a sequencer that controls the lifting and lowering operation of the molding mold 70. The controller 190 controls various operations of the bending apparatus 10 described below in cooperation with the line control PLC based on the output value of the pressure sensor and the like.

  4 (A) to 4 (C) are diagrams showing the glass sheet bending method realized by the bending apparatus 10 according to the present invention in time series. Specifically, FIG. 4A shows a glass plate G in which the molding mold 70 is lowered and the molding surface 73 b (the region of the molding surface 73 for performing the deepest drawing) is placed on the support frame 60. 4B shows a second stage in which the molding mold 70 is in the final molding position (the lowest position), and FIG. 4C shows the end of molding. A third stage in which the molding mold 70 later rises while adsorbing and holding the glass plate G is shown.

  FIG. 5 shows, in chronological order, how the negative pressures of the suction chambers 80a, 80b, and 80c change in the process from the first stage to the third stage shown in FIGS. 4 (A) to 4 (C). In the horizontal axis (time axis) of FIG. 5, time zones corresponding to the respective stages shown in FIGS. 4A to 4C are shown as an example. In FIG. 5, Pa is a negative pressure in the suction chamber 80a, Pb is a negative pressure in the suction chamber 80b, and Pc is a negative pressure in the suction chamber 80c. In addition, the change mode of the suction pressure acting on the glass plate G through the suction holes 74a, 74b, 74c of each group is substantially the same as the change mode of the negative pressure of each suction chamber 80a, 80b, 80c. .

  First, when the glass plate G is placed on the support frame 60 from the flat mold 35 and the support frame 60 moves to a position facing the molding mold 70, the molding mold 70 starts to descend, and eventually FIG. ), The glass plate G is started to be molded by pressing a part of the glass plate G supported by the support frame 60 against the molding surface 73b of the molding mold.

  At substantially the same time (or immediately before a part of the glass plate G is pressed against the molding surface 73b of the molding mold 70), the negative pressure in the suction chamber 80b is increased as shown in FIG. That is, the on-off valve 146b of the first negative pressure supply path 140b for the suction chamber 80b is opened, the negative pressure of the buffer tank 144b is guided to the suction chamber 80b, and the negative pressure Pb of the suction chamber 80b increases. Accordingly, the suction pressure acting on the glass plate G rises through the suction hole 74b communicating with the suction chamber 80b, and the glass plate G is sucked to the molding surface 73b of the molding mold 70, thereby forming the molding mold. The molding of the glass plate G along the molding surface 73b of 70 is promoted. Hereinafter, molding in which the shape of the glass plate G is aligned with the molding surface 73 of the molding mold 70 by the suction pressure acting on the glass plate G through the suction holes 74 is also referred to as “suction molding”.

  At this stage, a cross vacuum vacuum source 160 (see FIG. 3) is connected to the other suction chambers 80a and 80c. The cross vacuum vacuum source 160 supplies a negative pressure (for example, −50 mmAq) that is low enough to suck the cloth 75 to the molding surface 73 b of the molding mold 70.

  Next, when the molding mold 70 gradually descends, as shown in FIG. 4B, the molding mold 70 reaches the final molding position (the most lowered position). The molding mold 70 is held for a certain time at the final molding position. Thereby, the glass plate G is shape | molded entirely by pressing the substantially whole glass plate G supported by the support frame 60 against the shaping | molding surface 73 of a shaping | molding mold.

  During this fixed time (during the second stage), as shown in FIG. 5, first, the negative pressure in the suction chamber 80c is increased. That is, the communication between the suction chamber 80c and the cross vacuum vacuum source 160 is cut off, the on-off valve 146c of the first negative pressure supply path 140c to the suction chamber 80c is opened, and the negative pressure of the buffer tank 144c is transferred to the suction chamber 80c. The negative pressure Pc in the suction chamber 80c increases. Accordingly, the suction pressure acting on the glass plate G rises through the suction hole 74c communicating with the suction chamber 80c, and the glass plate G is sucked to the molding surface 73c of the molding mold 70, thereby forming the molding mold. The molding of the glass plate G along the molding surface 73c of 70 is promoted. Next, the negative pressure in the suction chamber 80a is increased after a time difference has elapsed since the on-off valve 146c of the first negative pressure supply path 140c is opened. That is, the suction chamber 80a is disconnected from the cross vacuum vacuum source 160, and the on-off valve 146a of the first negative pressure supply path 140a to the suction chamber 80a is opened, so that the negative pressure of the buffer tank 144a is transferred to the suction chamber 80a. And the negative pressure Pa of the suction chamber 80a increases. Accordingly, the suction pressure acting on the glass plate G is increased through the suction hole 74c communicating with the suction chamber 80a, and the glass plate G is sucked to the molding surface 73a of the molding mold 70, thereby forming the molding mold. The molding of the glass plate G along the molding surface 73a of the 70 is promoted.

  As described above, in this embodiment, by supplying a predetermined high negative pressure to the plurality of suction chambers 80a, 80b, and 80c while providing a time difference, a molding mold is applied without applying an excessive load to the glass plate G. The glass plate G can be efficiently molded along the molding surface 73 of 70.

  In the above-described embodiment, as shown also in FIG. 5, the timing at which the negative pressure for suction molding is supplied to each of the suction chambers 80 a, 80 b, and 80 c is the timing of the glass plate G relative to the molding surface 73 of the molding mold 70. Although it is defined in relation to the position, such timing is adapted depending on the shape of the molding surface 73 of the molding mold 70, the magnitude of the required suction pressure, and the like. It is not limited to such suction start timing.

  By the way, if a time difference is provided for the plurality of suction chambers 80a, 80b, and 80c as described above, the time from the start of suction molding by the first suction chamber 80b to the end of suction molding by the last suction chamber 80a is completed. Since the time becomes longer, the time during which the suction pressure acts on the portion of the glass plate that is suction-molded by the first suction chamber 80b (the portion that is pressed against the molding surface 73b of the molding mold 70) becomes longer. There is a possibility that surface roughness (particularly surface roughness due to transfer of the surface of the cloth 75) may occur in the portion.

  Therefore, in this embodiment, as shown in FIG. 5, the negative pressures of the suction chambers 80a, 80b, and 80c are raised as described above and then lowered independently. The timing of this lowering is a stage at which the time required for the suction molding by the respective suction chambers 80a, 80b, 80c has elapsed, and is appropriately determined for each of the suction chambers 80a, 80b, 80c.

  Specifically, as shown in FIG. 5, the negative pressure in the suction chamber 80b is increased to a predetermined negative pressure for suction molding, and the time necessary for suction molding has elapsed (time tb in FIG. 5). Thus, the opening / closing valve 146b of the first negative pressure supply path 140b for the suction chamber 80b is closed, and the opening / closing valve 156b of the second negative pressure supply path 150b for the suction chamber 80b is opened. At this time, the high negative pressure guided to the suction chamber 80b is weakened to the predetermined negative pressure range Ph via the regulator 152b (it is weakened by introducing atmospheric pressure via the regulator 152b). The pressure range Ph is a negative pressure range in which the surface roughness of the glass plate G due to the cloth 75 or the like does not occur, and is, for example, −300 to −50 [mmAq]. The negative pressure may be gradually reduced at a predetermined speed (for example, 333 mmAq / sec) via the regulator 152b so that the negative pressure is quickly reduced to the negative pressure range Ph. The negative pressure of the suction chamber 80b lowered in this way is at least a predetermined value until the negative pressure drop for the suction chamber 80a at which the negative pressure is finally lowered is completed (at least until time te in FIG. 5). The negative pressure range Ph is maintained.

  Similarly, when the negative pressure in the suction chamber 80c is increased to a predetermined negative pressure for suction molding and the time necessary for suction molding has elapsed (time tc in FIG. 5), the first negative pressure with respect to the suction chamber 80c is reached. The on-off valve 146c of the pressure supply path 140c is closed, and the on-off valve 156c of the second negative pressure supply path 150c for the suction chamber 80c is opened. At this time, the high negative pressure guided to the suction chamber 80c is weakened through the regulator 152c to the same predetermined negative pressure range Ph. The negative pressure of the suction chamber 80c lowered in this way is at least a predetermined value until the negative pressure drop with respect to the suction chamber 80a at which the negative pressure is finally lowered is completed (at least until time te in FIG. 5). The negative pressure range Ph is maintained.

  Similarly, when the negative pressure in the suction chamber 80a is increased to a predetermined negative pressure for suction molding and the time necessary for suction molding has elapsed (time ta in FIG. 5), the first negative pressure with respect to the suction chamber 80a is reached. The on-off valve 146a of the pressure supply path 140a is closed, and the on-off valve 156a of the second negative pressure supply path 150a for the suction chamber 80a is opened. At this time, the high negative pressure guided to the suction chamber 80a is weakened through the regulator 152a to the same predetermined negative pressure range Ph.

  In this way, when the negative pressure drop with respect to the suction chamber 80a where the negative pressure is finally lowered is completed (time te in FIG. 5), the molding process is completed, and as shown in FIG. The mold 70 rises in a state where the molded glass plate G is sucked and held on the molding surface 73. The molding mold 70 delivers the molded glass plate G to the next step (for example, quench ring), and ends the molding operation on the glass plate G. Specifically, the open / close valves 156a, 156b, 156c of the second negative pressure supply paths 150a, 150b, 150c to the suction chambers 80a, 80b, 80c are closed, and the open / close valves (dampers) 136a, 136b, 136c are opened, The suction chambers 80a, 80b, and 80c communicate with the positive pressure supply paths 130a, 130b, and 130c, respectively. As a result, a positive pressure is guided to each of the suction chambers 80a, 80b, and 80c, and the negative pressure in each of the suction chambers 80a, 80b, and 80c deviates from the above-described negative pressure range Ph and is held by suction. Falls. At this time, the glass plate G is received by, for example, a quench ring moved to a position directly below the molding mold 70 and flows to the next process.

  As described above, according to the present embodiment, the negative pressure in each of the suction chambers 80a, 80b, 80c, which has been increased to the negative pressure necessary for the suction molding, is at the stage when the time necessary for the suction molding has elapsed (time). ta, tb, tc) are sequentially lowered, and as a result, a negative pressure drop is started with a time difference (ta-tb, ta-tc, etc.). As a result, it is possible to prevent the surface roughness of the glass plate G caused by the cloth 75 or the like that may be generated when a high negative pressure is maintained for a longer time than necessary. On the other hand, for example, as shown in FIG. 9, negative pressure is supplied to all the suction chambers 80a, 80b, and 80c when the time necessary for the suction molding by the last suction chamber 80a has elapsed (time ta in FIG. 9). In the conventional configuration in which the pressure is released at the same time and the positive pressure is supplied for delivery to the subsequent process, a high negative pressure for suction molding is longer than necessary for each of the suction chambers 80b and 80c other than the suction chamber 80a. It will be held | maintained over time and the surface roughness of the glass plate G by the cloth | cross 75 may arise.

  In this embodiment, the time required for the suction molding via the suction chambers 80a, 80b, 80c depends on the shape of the molding surface 73 of the molding mold 70, the magnitude of the required suction pressure, etc. It is a parameter that should be adapted and derived by calculation and testing. Further, the opening / closing of each on-off valve 136, 146, 156 (that is, switching of the supply path) is performed by the controller 190 based on the deviation between the output signal of the pressure sensors 192a, 192b, 192c, etc. and a given target value. Control may be performed in a feedback manner, or may be controlled in a feed forward manner in accordance with an opening / closing timing derived in advance.

  Further, in this embodiment, the order of the negative pressure drop for each of the suction chambers 80a, 80b, 80c is the same as the order of the negative pressure rise for each of the suction chambers 80a, 80b, 80c. The timing is determined according to the minimum time necessary to realize the desired suction molding, and therefore depends on the shape of the molding surface 73 of the molding mold 70, the magnitude of the necessary suction pressure, and the like. The negative pressure drop timings for the two suction chambers may be substantially the same, or the negative pressure increase order and the negative pressure drop order may be reversed.

  Next, another embodiment of the present invention will be described. The basic configuration of the glass plate bending apparatus 10 and the like is the same as that of FIG. 1 described above, and a detailed description of the same parts is omitted. Hereinafter, although each structure is explained in full detail, the same code | symbol is attached | subjected and demonstrated about the same component as above-mentioned embodiment.

  The molding mold 70 of the present embodiment will be described with reference to FIG. 6 because the suction chambers 80a, 80b, 80c of FIG. FIG. 6 shows a molding surface 73 in plan view of the molding mold 70 and shows that the molding surface 73 is divided into three regions. The molding surface 73 has a curved longitudinal section, and a plurality of suction holes 74 are formed densely over substantially the entire surface, but are omitted in FIG. The molding surface 73 may be covered with a cloth (surface material such as a metal cloth or a glass cloth).

  The three areas of the molding surface 73 include a central molding surface 73k, an inner molding surface 73j, and a peripheral molding surface 73i, and the peripheral molding surface 73i is divided so as to surround the inner molding surface 73j and the central molding surface 73k. Has been. The central molding surface 73k and the inner molding surface 73j correspond to the visible light transmission region of the glass plate, and the peripheral molding surface 73i corresponds to the black ceramic paste layer formed on the peripheral portion of the glass plate. . The three divided molding surfaces are connected to the suction chamber of the molding mold 70 (not shown, but are divided in the same manner as in FIG. 2. The suction chambers are connected to the molding surfaces 73i, 73j, 73k to be connected. Reference numerals are respectively referred to as 80i, 80j, and 80k.), And the suction chambers 80i, 80j, and 80k communicate with the plurality of suction holes 74.

  The suction chamber is divided into three parts, which are installed corresponding to the three molding surfaces 73i, 73j, 73k. The three suction chambers are set behind the molding surface 73 so as to cover substantially the entire molding surface 73 of the molding mold 70, and a perfect airtightness is secured between the chambers by walls or the like. It is divided into. A chamber pressure control device 100 installed outside the molding furnace 16 is connected to each suction chamber via a pipe (duct) 82.

  FIG. 7 is a circuit showing an atmospheric pressure release path portion of the main components of the chamber pressure control device 100 according to another embodiment (components of the glass sheet bending device 10 installed outside the molding furnace 16). FIG. Of the main components of the chamber pressure control apparatus 100 according to the present embodiment, the circuit diagram upstream from the pipe (duct) 82 is the same as FIG.

  In the present embodiment, the vacuum source (negative pressure source) 110, the blow source 120, and the cross vacuum vacuum source are respectively connected to the suction chambers 80i, 80j, and 80k through the pipes 82i, 82j, and 82k, as in FIG. 160 and connected to the atmospheric pressure release path 158 as shown in FIG. The atmospheric pressure release path 158 is a system for opening the suction chambers 80i, 80j, and 80k to the atmosphere so that the surface roughness of the glass plate G does not occur.

  Specifically, the atmospheric pressure release path 158 is provided by branching from the pipes 82 i, 82 j, 82 k, respectively, and is connected to the molding furnace 16 via an on-off valve (damper) 168. The atmospheric pressure release path 158 is provided with an atmosphere release valve 180 on the path from the pipes 82 i, 82 j, 82 k to the on-off valve 168. That is, the suction chamber 80i is connected to the molding furnace 16 through the pipe 82i, the atmospheric pressure release path 158i, and the on-off valve 168i, and the atmosphere release valve 180i is provided in the middle of the atmospheric pressure release path 158i. Similarly, the suction chamber 80j is connected to the molding furnace 16 through a pipe 82j, an atmospheric pressure release path 158j, and an on-off valve 168j, and an atmosphere release valve 180j is provided in the middle of the atmospheric pressure release path 158j. Similarly, the suction chamber 80k is connected to the molding furnace 16 through a pipe 82k, an atmospheric pressure release path 158k, and an on-off valve 168k, and an atmospheric release valve 180k is provided in the middle of the atmospheric pressure release path 158k.

  Opening each suction chamber 80i, 80j, 80k in this embodiment to atmospheric pressure means the following two patterns. One is to open the suction chambers 80i, 80j, and 80k to the pressure in the molding furnace 16. The other is to open the suction chambers 80 i, 80 j, 80 k to the atmospheric pressure outside the molding furnace 16. Communication of the suction chambers 80i, 80j, and 80k to the atmospheric pressure release path 158 is realized by closing the on-off valves 136, 146, and 156. Then, opening the suction chambers 80i, 80j, and 80k to the pressure in the molding furnace 16 is realized by closing the air release valve 180 and opening the on-off valve 168. Moreover, opening each of the suction chambers 80i, 80j, and 80k to the atmospheric pressure outside the molding furnace 16 is realized by opening the air release valve 180 and closing the on-off valve 168. When the suction chambers 80i, 80j, and 80k are not opened to atmospheric pressure, both the on-off valve 168 and the atmospheric release valve 180 are closed. Open / close control of the open / close valves 168 and 180 is realized by the controller 190 in the same manner as the open / close control of the open / close valves 136, 146, and 156.

  The glass plate bend forming method realized by the bending apparatus of the present embodiment is such that the forming mold 70 descends and the center portion forming surface 73k (the center portion of the forming surface 73 shown in FIG. 6 performing the deepest drawing). Are pressed against the glass plate G placed on the support frame 60, the second stage in which the molding mold 70 is at the final molding position (the lowest position), and for molding after the molding is completed. The mold 70 includes a third stage that rises while adsorbing and holding the glass plate G.

  FIG. 8 shows, in a time series, how the negative pressure changes in the suction chambers 80i, 80j, and 80k in the process from the first stage to the third stage. On the horizontal axis (time axis) in FIG. 8, time zones corresponding to each stage are shown as an example. In FIG. 8, Pi is a negative pressure in the suction chamber 80i, Pj is a negative pressure in the suction chamber 80j, and Pk is a negative pressure in the suction chamber 80k. In addition, the change mode of the suction pressure which acts on the glass plate G through the suction hole 74 of each group is substantially the same as the change mode of the negative pressure of each suction chamber 80i, 80j, 80k.

  First, when the glass plate G is placed on the support frame 60 from the flat mold 35 and the support frame 60 moves to a position facing the molding mold 70, the molding mold 70 starts to descend, and eventually the support frame 60 is moved to the support frame 60. A part of the supported glass plate G is pressed against the molding surface 73k of the molding mold, whereby the molding of the glass plate G is started.

  At substantially the same time (or immediately before a part of the glass plate G is pressed against the molding surface 73k of the molding mold 70), the negative pressure in the suction chamber 80k is increased as shown in FIG. The glass plate G is attracted to the molding surface 73k, and the deformation of the glass plate G along the molding surface 73k is promoted.

  At this stage, a cross vacuum vacuum source 160 (see FIG. 7) is connected to the other suction chambers 80i and 80j. The air in the molding furnace 16 sucked from the cross vacuum vacuum source 160 may be returned to the molding furnace 16 through a pipe 162 as shown in FIG. This prevents the temperature outside the molding furnace from becoming high, and is also efficient in terms of energy.

  Next, when the molding mold 70 is gradually lowered, the molding mold 70 reaches the final molding position (the most lowered position). The molding mold 70 is held for a certain time at the final molding position. Thereby, the glass plate G is shape | molded entirely by pressing the substantially whole glass plate G supported by the support frame 60 against the shaping | molding surface 73 of a shaping | molding mold.

  During this fixed time (during the second stage), as shown in FIG. 8, first, the negative pressure in the suction chamber 80j is increased, and then the negative pressure in the suction chamber 80i is increased. The glass plate G is attracted to the molding surfaces 73j and 73i of the molding mold 70, and the deformation of the glass plate G along the molding surfaces 73j and 73i is sequentially promoted. Thus, also in the present embodiment, the glass plate G is efficiently formed along the forming surface 73 of the forming mold 70 without applying an excessive load to the glass plate G.

  Further, since the time from the start of the suction molding by the first suction chamber 80k to the end of the suction molding by the last suction chamber 80i becomes longer, as shown in FIG. 8, the negative pressure of the suction chamber 80k is The high negative pressure led to the suction chamber 80b when the time required for the suction molding has elapsed (time tk in FIG. 8) has been increased to the predetermined negative pressure for suction molding, A similar negative pressure range Ph (not shown in FIG. 8 but the same as FIG. 5) is weakened. The predetermined negative pressure range Ph is a negative pressure range in which the surface roughness of the glass plate G due to the cloth 75 or the like does not occur, and is, for example, −300 to −50 [mmAq]. The negative pressure may be gradually reduced at a predetermined speed (for example, 333 mmAq / sec) via the regulator 152b so that the negative pressure is quickly reduced to the negative pressure range Ph.

  Similarly, the negative pressure in the suction chamber 80j is increased to a predetermined negative pressure for suction molding, and the time required for suction molding has elapsed (time tj in FIG. 8), and the suction chamber 80j is guided to the suction chamber 80j. The high negative pressure is reduced to the same predetermined negative pressure range Ph.

  The negative pressure in the suction chamber 80i is increased to a predetermined negative pressure for suction molding, and when the time necessary for suction molding has elapsed (time ti in FIG. 8), the high negative pressure that has been introduced into the suction chamber 80i. The pressure is lowered to a predetermined negative pressure Pg shown in FIG. The negative pressure Pg is determined by the weight of the glass plate G and the like, and supports the molded glass plate G with the negative pressure Pg acting on the peripheral edge of the glass plate G.

  In this way, the negative pressures in the suction chambers 80i, 80j, and 80k are lowered, but at least the negative pressure in the suction chambers 80j and 80k is reduced until the negative pressure in the suction chamber 80i drops to a predetermined negative pressure Pg ( At least until the time te in FIG. 8), the predetermined negative pressure range Ph is maintained.

  When the negative pressure in the suction chamber 80i drops to the predetermined negative pressure Pg (time te in FIG. 8), the molding process is completed, and the molding mold 70 holds the molded glass plate G on the molding surface 73 by suction. To rise. Even in a state where the glass plate is adsorbed and held, the surface of the glass plate may still be rough. In this embodiment, in the third stage after the end of the molding process (time te in FIG. 8), the suction chambers 80j and 80k are opened to atmospheric pressure to prevent the surface roughness of the glass plate.

  After completion of the molding process (time te in FIG. 8), the negative pressure of the suction chambers 80j and 80k is further lowered, and the glass plate is molded by the negative pressure Pg of the suction chamber 80i acting on the peripheral edge of the glass plate G. Adsorb and hold. That is, the on-off valve 156b of the second negative pressure supply path 150b for the suction chamber 80k is closed, and the on-off valve 168k of the atmospheric pressure release path 158k for the suction chamber 80k is opened. At this time, the negative pressure in the suction chamber 80k is reduced to a pressure Pf close to the pressure in the molding furnace 16 through the atmospheric pressure release path 158k. Alternatively, the open / close valve 168k of the atmospheric pressure release path 158k for the suction chamber 80k may be closed and the atmospheric release valve 180k may be opened. In this case, the negative pressure in the suction chamber 80k is reduced to a pressure close to the atmospheric pressure outside the molding furnace 16 through the atmospheric pressure release path 158k.

  Similarly, the on-off valve 156c of the second negative pressure supply path 150c for the suction chamber 80j is closed, and the on-off valve 168j of the atmospheric pressure release path 158j for the suction chamber 80j is opened. At this time, the negative pressure in the suction chamber 80j is reduced to a pressure Pf close to the pressure in the molding furnace 16 through the atmospheric pressure release path 158j. Alternatively, the open / close valve 168j of the atmospheric pressure release path 158j for the suction chamber 80j may be closed and the atmospheric release valve 180j may be opened. In this case, the negative pressure in the suction chamber 80j is reduced to a pressure close to the atmospheric pressure outside the molding furnace 16 through the atmospheric pressure release path 158j.

  In this manner, the molding mold 70 sucks and holds the molded glass plate G, passes it to the next step (for example, quench ring), and ends the molding operation on the glass plate G. Specifically, the open / close valves 168j and 168k of the atmospheric pressure release paths 158j and 158k for the suction chambers 80j and 80k are closed, and the atmospheric release valves 180j and 180k are closed. Other than that, the suction chambers 80i, 80j, and 80k communicate with the positive pressure supply passages 130a, 130c, and 130b, respectively, and a positive pressure is guided to the suction chambers 80i, 80j, and 80k. The held glass plate G falls. At this time, the glass plate G is received by, for example, a quench ring moved to a position directly below the molding mold 70 and flows to the next process.

  As described above, according to the present embodiment, in the third stage after the molding process is completed, the glass plate G is further supported by the peripheral edge molding surface 73i corresponding to the black ceramic paste layer. The negative pressure acting on the visible light transmission region can be reduced. As a result, the surface roughness of the visible light transmission region of the glass plate G can be prevented. The peripheral edge molding surface 73i does not have to match the shape of the black ceramic paste layer, and may be a region narrower than the black ceramic paste layer depending on the shape of the glass plate, or from the black ceramic paste layer to the extent that surface roughness does not occur. May be a wide area.

  In this embodiment, the atmospheric pressure release for each of the suction chambers 80j and 80k was performed at the same time in the third stage. However, the timing of the opening depends on the minimum time necessary to realize the desired suction molding. Accordingly, the atmospheric pressure is released from the middle of the second stage depending on the shape of the molding surface 73 of the molding mold 70, the suction pressure of the suction chamber 80i, the weight of the glass plate, and the like. There may be cases. That is, the predetermined negative pressure of the suction chamber 80i at the peripheral edge when the suction chambers 80j and 80k are opened to atmospheric pressure is set higher than, for example, Pg shown in FIG. 8, and the suction chambers 80j and 80k are opened to atmospheric pressure. After that, the negative pressure of the suction chamber 80i at the peripheral edge may be lowered to Pg.

  In addition, the molding mold 70 starts to rise in the third stage after the molding process is finished, but the timing of the molding mold 70 rising starts from the middle of the second stage depending on the shape of the glass plate to be molded. In some cases, the molding time can be shortened, and the third stage is not necessarily required.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, in the above-described embodiment, the suction chamber is divided into three suction chambers 80a, 80b, 80c, or 80i, 80j, 80k, but may be divided into two suction chambers or four or more suction chambers. Is possible. For example, a suction chamber (not shown) to which a higher negative pressure is supplied may be provided in the region of the molding surface 73 that is particularly difficult to perform suction molding. As shown in FIG. 3, for example, another negative pressure supply path 170 from the vacuum source 110 and another positive pressure supply path 130d from the blow source are selectively provided in the pipe 82d connected to the suction chamber. It may be possible to communicate. In this case, the negative pressure adjusted from the other negative pressure supply path 170 from the vacuum source 110 to a predetermined pressure (a negative pressure higher than other negative pressure supply paths, for example, −3000 mmAq) by the regulator 172. May be supplied.

  In the embodiments shown in FIGS. 5 and 8, the negative pressures held in the buffer tanks 144a, 144b and 144c are made different so that the suction chambers 80a, 80b and 80c, or 80i, 80j and 80k are different. Although the negative pressure for suction molding to be supplied is different, the present invention is not limited to this, and independent negative pressure supply to each of the suction chambers 80a, 80b, 80c or 80i, 80j, 80k. A negative pressure for suction molding may be supplied from a common buffer tank by a path.

  Moreover, in the above-mentioned Example, although the shaping | molding of the glass plate is performed within the furnace, it may be performed outside a furnace. Moreover, in the above-mentioned Example, although the next process of the shaping | molding process by the shaping | molding apparatus 10 was a cooling process, there may exist a further shaping | molding process in the front | former stage of a cooling process.

  As described above, the present invention is not limited to the molding of window glass for automobiles, but can be applied to the molding of window glasses for other vehicles, aircraft, ships, buildings, and the like. Further, in the case where the deeply bent glass sheet G is formed in two or more stages, that is, preforming and main forming, it is applicable to both the pre-forming and the main forming.

It is sectional drawing which shows typically an example of the main line part containing the bending forming apparatus 10 of the glass plate by this invention. It is sectional drawing which shows one Example of the bending forming apparatus 10 of the glass plate which concerns on this invention. 2 is a circuit diagram showing a main configuration of a chamber pressure control device 100. FIG. 4 (A) to 4 (C) are diagrams showing the glass sheet bending method realized by the bending apparatus 10 according to the present invention in time series. It is a figure which shows the change mode of the negative pressure of each suction chamber 80a, 80b, 80c by a present Example in time series. It is a top view which shows the division | segmentation of the shaping | molding surface of the mold 70 for shaping | molding by another Example. It is a circuit diagram which shows the atmospheric pressure open path part of the chamber pressure control apparatus 100 by another Example. It is a figure which shows the change mode of the negative pressure of each suction chamber 80i, 80j, 80k by another Example in time series. It is a figure which shows the change mode of the negative pressure of each suction chamber 80a, 80b, 80c by a conventional structure in time series.

Explanation of symbols

G Glass plate 10 Glass plate bending apparatus 14 Heating furnace 35 Flat mold 60 Support frame 70 Mold for molding 73 Molding surface 74 Suction hole 75 Cross 80a, 80b, 80c, 80i, 80j, 80k Suction chamber 100 Chamber pressure control apparatus 110 Vacuum source 120 Blow source 140 First negative pressure supply path 150 Second negative pressure supply path 158 Atmospheric pressure release path 190 Controller

Claims (7)

In a method for bending a glass plate, comprising a heating step for heat-softening the glass plate, and a bending step for bending the heat-softened glass plate into a predetermined shape,
The bending process includes
Pressing the heat-softened glass plate, the edge of which is supported by the support frame, against the molding surface of the molding mold facing the support frame;
A suction molding step of supplying a negative pressure through a plurality of suction holes formed in the molding surface so that the shape of the pressed glass plate is along the molding surface of the molding mold,
The suction molding step divides the plurality of suction holes into at least two groups, lowers the increased negative pressure with a time difference for each group, and the negative pressure related to the group in which the negative pressure is reduced first is negatively to pressure is lowered, the method for bending a glass sheet, characterized that you suction holding the glass plate is maintained at a predetermined negative pressure range of the group last negative pressure is lowered. The glass plate bending method according to claim 1, wherein the negative pressure related to the group whose negative pressure has been lowered is a pressure (Ph) that can be adsorbed and held without surface roughness of the glass plate. The plurality of suction holes are composed of at least two groups of a central group on the molding surface of the molding mold and a peripheral group surrounding the central group.
Finally, the group in which the negative pressure is lowered is the group of the peripheral portion,
The negative pressure related to the group in which the negative pressure has been lowered first is in a predetermined negative pressure range in which the surface roughness of the glass plate does not occur until the negative pressure in the peripheral edge group is reduced to the predetermined negative pressure. The glass plate bending method according to claim 1, wherein the glass plate is maintained and then released to atmospheric pressure. The method for bending a glass plate according to claim 3, wherein the negative pressure of the group of peripheral portions is a predetermined negative pressure (Pg) determined by a weight of the glass plate or the like. In a glass plate bending apparatus for bending a glass sheet heated and softened in a heating furnace into a predetermined shape,
A support frame that supports an edge of the heat-softened glass plate;
A molding mold having a plurality of suction holes formed on the molding surface;
A plurality of suction chambers provided behind the molding surface of the molding mold and communicating with any of the plurality of suction holes of the molding mold;
A negative pressure supply circuit connected to the plurality of suction chambers and supplying negative pressure to the plurality of suction chambers;
A controller for controlling the negative pressure in the plurality of suction chambers for each suction chamber;
A mechanism for changing the position of the molding mold relative to the support frame so that the glass plate supported by the support frame is pressed against the molding surface of the molding mold;
The negative pressure supply circuit has a first negative pressure supply path for supplying a high negative pressure and a second negative pressure supply path for supplying a low negative pressure,
The controller controls the opening / closing valve of the first negative pressure supply path and the opening / closing valve of the second negative pressure supply path, so that the shape of the pressed glass plate is formed into the molding mold. with increasing the negative pressure of the plurality of suction chambers along the surface, is lowered with a time difference for each suction chamber negative pressure is the increased negative pressure in accordance with the group negative pressure above was drop The glass plate bending apparatus is characterized in that the glass plate is sucked and held in a predetermined negative pressure range until the negative pressure related to the group where the negative pressure is finally lowered . 6. The glass plate bending apparatus according to claim 5 , wherein the negative pressure relating to the group whose negative pressure has been lowered first is a pressure (Ph) that can be adsorbed and held without causing surface roughness of the glass plate. The plurality of suction chambers comprises at least two suction chambers, a suction chamber at a central portion on a molding surface of the molding mold and a suction chamber at a peripheral portion surrounding the suction chamber at the central portion,
Each of the plurality of suction chambers is connected to an atmospheric pressure release path,
The controller controls the open / close valve of the first negative pressure supply path, the open / close valve of the second negative pressure supply path, and the open / close valve of the atmospheric pressure release path, thereby controlling the inside of the suction chamber at the peripheral portion. Lastly, the negative pressure is lowered, and the negative pressure in the suction chamber where the negative pressure has been dropped first becomes rough until the negative pressure in the suction chamber at the peripheral edge is lowered to the predetermined negative pressure. and maintaining a negative pressure range not, then opens the atmospheric pressure a negative pressure of the destination suction chamber negative pressure is lowered, the glass plate of the bending device according to claim 5.

Images