JP2000335931A - Gripping device for processing of optical fiber preform - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the automatic gripping action of an optical fiber preform even in a deformed state of the preform, enable good drawing work of the preform in a heating furnace and form a good optical fiber strand. SOLUTION: A universal joint 11 is placed at an upper holding part 1 to hold the upper part of an optical fiber preform 10, an XY table mechanism movable in a plane in perpendicularly crossing directions is attached to the lower holding part 2 for holding the lower part of the optical fiber preform 10, the position of the preform 10 in radial direction is measured by an outer diameter measuring device 3, the upper holding part is rotated in proper direction based on the position information of the optical fiber preform 10 detected and confirmed by the outer diameter measuring device 3 in the heating of the optical fiber preform 10 in a heating furnace 4 and the heating part of the optical fiber preform 10 is made to be constantly positioned at the center of the heating furnace 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for adjusting the position of an optical fiber preform with respect to a heating furnace by performing a movement adjusting operation of a gripping portion for gripping an optical fiber preform during a drawing operation during the production of an optical fiber. The present invention relates to a gripping device for optical fiber preform processing that can be performed.

[0002]

2. Description of the Related Art In the VAD method, for example, an optical fiber is manufactured by performing a drawing process after a soot synthesis process and a dehydration / sintering process. In this drawing process, an optical fiber preform is heated in a heating furnace. The wire is drawn by pulling it downward.

[0003] In this drawing operation, the upper and lower ends of the optical fiber preform are rotated in a heating furnace while holding the upper and lower ends of the optical fiber preform by grips (for example, a scroll type). While pulling, the optical fiber preform is sequentially pulled downward from the softened portion (lower side) to form a small-diameter optical fiber (element wire).

[0004]

However, in order to perform a good drawing operation, the operation of heating and softening the optical fiber preform in a heating furnace must be performed in a uniform state in which the optical fiber preform has no unevenness in the radial direction. However, it is important that the optical fiber preform used is not necessarily formed in a straight state, and may be slightly bent during the production or the like. As a result, the temperature of the optical fiber preform is likely to be uneven in the heating state of the optical fiber preform in the heating furnace, and the formed wire may be eccentric, for example, leading to a deterioration in quality.

In view of the above circumstances, the present invention can realize an automatic gripping operation of an optical fiber preform even when the optical fiber preform is deformed, and perform a good drawing operation in a heating furnace. It is an object of the present invention to provide a gripping device for processing an optical fiber preform, which is capable of forming a good optical fiber.

[0006]

That is, according to the first aspect of the present invention, when the optical fiber preform is drawn while being heated, the upper end of the optical fiber preform is gripped from the side by the upper grip portion. An optical fiber preform processing gripping device for gripping the lower end side of the optical fiber preform from the side with a lower gripping portion and adjusting the position of the optical fiber preform in a heating furnace. A universal joint is provided in an upper grip portion for gripping an upper portion, and an XY table mechanism movable in two directions orthogonal to each other on a plane is provided in a lower grip portion for gripping the lower portion of the optical fiber preform, and the optical fiber preform radius is provided. Equipped with an outer diameter measuring device for measuring the position of the optical fiber preform in the direction, and when the optical fiber preform is heated by a heating furnace, the position information of the optical fiber preform measured and confirmed by the outer diameter measuring device is used. Based on Heating part of the grip portion is rotated in the appropriate direction the optical fiber preform is obtained by configured to be located always at the center of the furnace.

[0007]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an optical fiber preform processing gripping device according to an embodiment of the present invention. In the gripping device for processing an optical fiber preform of this embodiment, the universal joint 11 is provided on the upper grip 1 side, and the XY table mechanism (not shown) is provided on the lower grip 2 side.
And an outer diameter measuring device 3. Note that reference numeral 10 in the drawing indicates an optical fiber preform.

The upper gripping portion 1 employs a slide-type chuck which is convenient for automating the gripping operation of the optical fiber preform 10, and the optical fiber preform 1 is in an upright state.
Optical fiber preform 10 traveling from the side to
(Dummy bar) can be gripped at the upper end side. Further, since the universal joint 11 is attached to the upper gripping portion 1 so that the swinging operation can be performed, even if the optical fiber preform is slightly deformed, it can be freely rotated in any direction by 360 degrees. Can be swung.

The lower gripper 2 is driven by a drive motor 21 of an XY table mechanism (see FIG. 2) to move the XY2
The optical fiber preform 1 can be freely moved in the direction (however, parallel to the horizontal plane), and thus slightly deformed.
Even if it is 0, the lower end can be reliably gripped. In addition, since the lower gripping portion 2 grips the optical fiber preform 10 which is gripped by the upper gripping portion 1 and descends from above, directly below the optical fiber preform 10, especially when the gripping operation of the optical fiber preform 10 is automated, the slide type is used. It is not necessary to use the chuck, and a scroll type similar to the conventional one may be used.
Further, as the XY table mechanism, a known one having an appropriate configuration operated by a drive motor can be used.

The outer diameter measuring device 3 constantly measures the outer diameter position of the optical fiber preform 10 descending from above while being gripped by the upper gripping portion 1, so that the heating furnace on the XY (coordinates) can be measured. (4) The distance from the inner peripheral surface to the outer peripheral surface of the optical fiber preform 10 is sequentially detected, and is optically detected by using appropriate means, for example, a laser in this embodiment. I have. Further, the outer diameter measuring device 3 is disposed immediately above the heating furnace 4, and is adjusted in position to be concentric with the heating furnace 4. The outer diameter measuring device 3 of this embodiment includes a light emitting unit 31 for emitting laser light or the like and a light receiving unit 32 for receiving light from the light emitting unit 31. Also, from the light receiving section 32 of the outer diameter measuring device 3,
A detection signal corresponding to the measured data is output to the control unit 5 shown in FIG.

The heating furnace 4 is composed of a cylindrical one (not particularly limited to this) concentrically arranged with a cylindrical chamber (not shown). As shown in FIG. 3, adjustment is made so that the center axis A of the optical fiber preform 10 is arranged exactly at the central portion O.

The control unit 5 receives a detection signal from the outer diameter measuring device 3 and constantly detects and specifies the position of the optical fiber preform 10 on the XY coordinates based on this signal. At this time, an appropriate control signal according to the current position of the optical fiber preform 10 to be detected is transmitted to the XY
The output is output to the drive motor 21 of the table mechanism.

Therefore, according to this embodiment, as shown in FIG. 3, although the optical fiber preform 10 is suspended by the upper grip 1, the optical fiber preform 10 is deformed relative to the dummy rod. Even if it is formed (tilted), since the universal joint 11 is used, the dummy rod is gripped by the upper gripping part 1 in an arbitrary shape, for example, by holding it in an oblique state, etc. It is possible to suspend the material 10 in a vertical state. In this way, when the optical fiber preform suspended vertically is lowered vertically downward along with the lowering operation of the upper grip 1, the outer diameter measuring device 3 corresponds to the axial direction of the optical fiber preform 10. The respective outer peripheral surface positions (shapes) are sequentially detected, and are stored as information on Cartesian coordinates (X, Y) in, for example, a memory provided in the control unit 5.

At this time, since a signal corresponding to the detected value is output from the outer diameter measuring device 3 to the control unit 5, a predetermined reference position (for example, origin O) of the optical fiber preform 10 is determined.
When the control unit 5 determines that there is a deviation exceeding a permissible value from the position (0,0) exactly at the position where the center axis A of the optical fiber preform 10 coincides with the center axis A, the deviation from the control unit 5 A control signal corresponding to the amount is output to the drive motor 21.

The drive motor 21 which has received the control signal operates according to the control signal, and the lower grip 2 moves to a predetermined coordinate position by an appropriate amount along each of the X and Y directions. That is, the optical fiber preform 10 moves to just below the dummy bar. After that, if the further lowering dummy rod is gripped by the lower gripping portion 2, the lowering operation is temporarily stopped, and then the drawing operation is started while heating in the heating furnace 4.

As described above, when the drawing operation is started, the outer diameter position of the optical fiber preform 10 is changed based on the outer diameter data measured by the outer diameter measuring device 3 and stored in the control section 5. According to the control signal from the control unit 5 in accordance with
Activate the Y table mechanism. Thus, the drive motor 21 is sequentially operated and adjusted so that the center axis A of the optical fiber preform 10 exactly coincides with the center of the heating furnace 4.

As a result, at least when the optical fiber preform 10 passes through the heating furnace 4, the optical fiber preform 1
The dummy rod on the lower side of the optical fiber preform 10 is appropriately moved in the XY directions together with the lower grip 2 so that the distance between the outer peripheral surface of the heating fiber 4 and the inner peripheral surface of the heating furnace 4 is uniform and constant in all directions. I do. Further, the optical fiber preform 10 which is not moved but is held in the omnidirectionally rotatable state at the upper grip 1 via the universal joint 11 can absorb the displacement on the upper side due to the XY moving operation. In addition, it is possible to prevent a trouble that the upper side cannot follow the forcible moving operation of the lower side of the optical fiber preform and breaks.

As a result, the optical fiber preform 10 is drawn while being uniformly and uniformly heated in the heating furnace 4.
A high quality optical fiber preform is formed.

[0019]

As described above, according to the present invention, there is provided an outer diameter measuring device for measuring the radial position of the optical fiber preform, and the optical fiber mother measured and confirmed by the outer diameter measuring device. At least one of the upper gripping portion and the lower gripping portion is moved and adjusted based on the position information of the material, and when the optical fiber preform is heated by the heating furnace, the heated portion of the optical fiber preform is always in the heating furnace. Because it is configured to be at the center position, for example, even if the gripping rod is displaced from the vertical direction with respect to the optical fiber preform, the position adjustment of the heating portion of the optical fiber preform with respect to the heating furnace can be performed by lower gripping. This can be properly performed by the XY table mechanism attached to the section, and a high-quality optical fiber can be formed.

Further, according to the present invention, the universal joint is also provided in the upper gripping portion, so that when the lower side of the optical fiber preform is appropriately moved by the XY table mechanism, the upper side follows the position and changes its position. Can be absorbed, so that it is possible to prevent a trouble that an excessive force acts on the upper gripping portion and breaks due to the movement of the lower side.

Further, in the configuration using a slide-type chuck for the upper grip portion, the upper side of the optical fiber preform in the upright state is gripped by the upper grip portion moving from the side, Also, while lowering the optical fiber preform fixed by the upper gripping part, the outer diameter measuring device measures the position information of the optical fiber preform, and based on this information, the XY table mechanism causes the XY table mechanism to lower the lowering part of the lower gripping part. Since it can be moved directly below the fiber preform, the lower side of the optical fiber preform can be dropped from above into the lower grasping part and grasped,
It becomes possible to realize fully automatic gripping of the optical fiber preform during the drawing operation.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a gripping device for processing an optical fiber preform according to the present invention.

FIG. 2 is a configuration block diagram of the device.

FIG. 3 is an explanatory view showing the operation of the device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper grip part 2 Lower grip part 3 Outer diameter measuring instrument 4 Heating furnace 10 Optical fiber preform 11 Universal joint

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Nozomi Agawa 1440 Mutsuzaki, Sakura City, Chiba Prefecture Inside Fujikura Sakura Office Co., Ltd. Terms (reference) 3C016 CB06 CE02 4G021 HA00

Claims (2)

[Claims] When an optical fiber preform is drawn while being heated, the upper end of the optical fiber preform is gripped from the side by an upper grip portion, and the optical fiber preform is held. (10) The lower end side is gripped from the side by the lower gripper (2), and the optical fiber preform (10) in the heating furnace (4) is held.
An optical fiber preform processing gripping device for adjusting the position of the optical fiber preform, wherein a universal joint (11) is provided in an upper grip portion (1) for gripping an upper portion of the optical fiber preform (10), and the optical fiber preform is provided. (10) An XY table mechanism that is movable in two directions orthogonal to each other on a plane is provided on a lower grip portion (2) that grips the lower portion, and the optical fiber preform (10) is an optical fiber preform (10) in a radial direction. An outer diameter measuring device (3) for measuring the position of the optical fiber preform (10). The upper gripping portion is rotated in an appropriate direction based on the position information of the material (10) so that the heating portion of the optical fiber preform (10) is always located at the center of the heating furnace (4). Characteristic gripping device for optical fiber preform processing. 2. The gripping device for processing an optical fiber preform according to claim 1, wherein at least the upper gripping portion comprises a slide type chuck.