JPH07277758A - Method and device for drawing optical fiber - Google Patents

Abstract

PURPOSE:To feed plural optical fiber preforms into a heating device without causing the vibrations and axial slippage of the preforms. CONSTITUTION:A holding device 3 for suspending and holding plural optical fiber preforms is provided with a pair of arms 42, 42 capable of being opened or closed around a prescribed position D, and claw parts 44, 44 disposed on the inner sides of the arms 42, 42, respectively. The holding device is further especially provided with an XY free-table 30 for smoothly transferring the arms 42, 42 in the horizontal direction, and support mechanisms 43, 43 for supporting the claw parts 44, 44 in a state capable of being oscillated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber drawing method and an apparatus for drawing an optical fiber by drawing an optical fiber preform.

[0002]

2. Description of the Related Art The structure of a conventionally known optical fiber drawing apparatus will be described with reference to FIG. Above the heating device 8 for melting and drawing the optical fiber preform, two holding devices 3 and 4 for suspending and holding the optical fiber preforms 12 and 11, respectively, are provided. At the side portions of the holding devices 3 and 4, feeding mechanisms 5 and 6 for independently raising and lowering the holding devices 3 and 4, and holding devices 3 and 4.
A welding device 7 for connecting the optical fiber preforms 12 and 11 held by the optical fiber preforms 4 is provided so that the optical fiber preforms 11 and 12 can be integrated by welding and supplied into the heating device 8. There is. Holding device 3,4
A sensor 9 for detecting the outer diameters / positions of the optical fiber preforms 11 and 12 is provided below, and the holding devices 3 and 4 are drive-controlled based on a signal from the sensor 9.

The optical fiber preforms 11 and 12 supplied to the heating device 8 are heated and melted in the heating device 8 and drawn out as an optical fiber 14. The optical fiber 14 drawn out from the heating device 8 passes through a precoat device 15 to be coated on the surface, and then is taken up by a winding device 17 via a drawing device 16.

Reference numeral 10 denotes a sensor for detecting the outer diameter / position of the optical fiber 14 immediately after being pulled out from the heating device 8. The outer diameter control of the optical fiber 14 is performed by controlling the speed of the take-up device 16 by the outer diameter control circuit 18 based on the signal from the sensor 10.

FIG. 10 is a diagram showing a series of operations of the optical fiber drawing method, particularly, a series of operations when the optical fiber preforms 11 and 12 are continuously supplied to the heating device 8.

First, as shown in (1), the welded optical fiber preform 11 is held by the upper holding device 3, and in this state, the holding device 3 is lowered at a constant speed,
The optical fiber preform 11 is fed into the heating device 8 and melt-drawn. During the drawing, when the welded portion of the optical fiber preform 11 is detected by the sensor 9, as shown in (2), the lower holding device 4 holds the optical fiber preform 11 and then As in 3), the holding device 3 on the upper side of 11 is separated from the optical fiber preform.

Thereafter, the upper holding device 3 is raised to a predetermined position as shown in (4) and holds a new optical fiber preform 12 to be supplied next. When the holding device 3 descends while holding the optical fiber preform 12, and the lower end of the optical fiber preform 12 comes into contact with the upper end of the optical fiber preform 11 with a constant force, as shown in (5), the optical fiber Welding device 7 between preforms 11 and 12
Weld by. Here, the optical fiber preform 1
The pressure contact force between 1 and 12 is determined in consideration that the optical fiber preform 11 does not fall off from the lower holding device 4 and that the optical fiber preforms 11 and 12 are not damaged in quality. .

When the welding is completed, as shown in (6), the lower holding device 4 is separated from the optical fiber preform 13 integrated by welding. As a result, the above (1)
The state is returned to, and the series of operations is completed.

[0009]

However, the holding devices 3 and 4 in the above-described wire drawing device are conventionally provided with a pair of arms that can be opened and closed on a lift table that moves up and down in the vertical direction.
It is a structure in which a chuck (claw) is attached to the inside of these arms. Therefore, as shown in FIG. 10 (2),
When the optical fiber preform 11 already held by the holding device 3 on the upper side is held by the holding device 4 on the lower side, the optical fiber preform 11 is caused by a slight bend or undulation of the optical fiber preform 11. There is a possibility that vibration and misalignment may occur at 11, causing various harmful effects. For example,
The optical fiber preform 11 collides with the upper seal cup 8a which is the insertion port of the heating device 8, or the position of the optical fiber 14 during drawing is out of the measurable area of the sensor 10,
The control of the outer diameter of the optical fiber 14 may be disabled.

The above-mentioned vibration and axis deviation of the optical fiber preform cause the holding device 3 above the optical fiber preform 11 to be held when the holding device 4 below the optical fiber preform 11 is held. When separated (Fig. 1
0 (3)), it also occurs when the lower holding device 4 is separated from the optical fiber preform 13 after welding (FIG. 10 (6)).

Further, when the optical fiber preforms 11 and 12 are integrated by welding by the conventional optical fiber drawing device, the optical fiber preforms 11 and 12 are welded due to delicate bending, undulation, distortion due to welding, etc. The subsequent optical fiber preform 13 is misaligned, and the optical fiber preform 13 is attached to the upper seal cup 8a of the heating device 8.
There is also a risk that the optical fiber 14 will come into contact with the lower seal cup 8b and break.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to supply a plurality of optical fiber preforms smoothly and continuously into the heating device without causing vibrations or axis deviations. It is to provide a drawing method and a drawing apparatus.

[0013]

In order to achieve the above object, in the optical fiber drawing method of the present invention, a pair of arms for opening and closing around a predetermined position are horizontally provided in the upper and lower holding devices. And the claws that engage with the optical fiber preform are swingable inside the arms, and the arms and claws are in a movable and swingable state. The optical fiber preform is gripped and opened by opening and closing the arm, and then the arm and the claw portion are constrained to be immovable.

Further, the optical fiber drawing apparatus of the present invention comprises a pair of arms for opening and closing the upper and lower holding devices and a pair of arms which can engage with the surface of the optical fiber preform from both sides. Claw portion, an XY free table for smoothly moving the arm in the horizontal direction, and a support mechanism for swingably supporting the claw portion inside the both arms, respectively. The mechanism is provided with means for preventing movement of the arm and means for preventing swinging of the claw portion.

The support mechanism includes a first holder rotatably supported inside the arm and a second holder rotatably supporting the claw portion and forward and backward in front of the first holder. It is preferable to include the holder and the elastic member that is provided between the first and second holders and biases the second holder forward.

[0016]

In the present invention, the pair of arms that open and close around a predetermined position are made movable in the horizontal direction by the XY free table, and the arms are opened and closed in this state, so that the optical fiber preform bends. Even if the arm moves from its original position due to undulations, the arm moves to that position to open and close, so that the optical fiber preform can always be gripped and opened at the optimum position. Moreover, since the claw portions are provided on the inner sides of the both arms by the support mechanism so as to be able to swing freely, the optical fiber preform can be gripped and released according to its inclination and surface shape. Therefore,
It is possible to soften the impact when gripping and opening the optical fiber preform, and to suppress the vibration and misalignment of the optical fiber preform.

Here, if an elastic member is provided in the support mechanism to support the inside of the arm while the claw portion is biased forward, the impact at the time of gripping and releasing the optical fiber preform is further increased. Can be absorbed by the elastic member, resulting in more vibration
It is possible to suppress the axis deviation.

[0018]

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

FIG. 1 is a schematic view showing the overall structure of an optical fiber drawing device 1 according to the present invention. In FIG. 1, 8 is a heating device for melting and drawing an optical fiber preform. Above the heating device 8, two holding devices 3 and 4 for suspending and holding the optical fiber preforms 12 and 11, respectively, are provided. As in the conventional case, these holding devices 3 and 4 are provided to be vertically movable on guide bars 2 and 2 arranged along the vertical direction, and can be raised and lowered independently of each other by the feeding mechanisms 5 and 6. It has become.

A welding device 7 for abutting and welding the ends of the optical fiber preforms 12 and 11 is provided on the side portions of the lifting regions of the holding devices 3 and 4. Further, a sensor 9 for detecting the outer diameters and the positions of the optical fiber preforms 11 and 12 is provided immediately below the lifting regions of the holding devices 3 and 4.

Reference numeral 19 is a control device for driving and controlling the upper and lower holding devices 3 and 4 based on the signal from the sensor 9.

FIG. 2 is a diagram showing a configuration example of the holding devices 3 and 4 in the optical fiber drawing device 1. In the following, only the upper holding device 3 will be described, and the lower holding device 4 will not be described because it has the same structure.

In FIG. 2, reference numeral 40 is an opening / closing chuck for suspending and holding an optical fiber preform, and a base 41.
A pair of arms 42, 42 are provided on the top. The arms 42, 42 are reciprocally movable by a rail 41a and extend in a direction orthogonal to the rail 41a. Inside the extending ends of the arms 42, 42, claw portions 44, 44 capable of engaging with the surface of the optical fiber preform from both sides.
Is provided. V-grooves 44 are provided on the facing surfaces of the claw portions 44, 44.
a and 44a are formed to position and hold the optical fiber preform. On the other hand, an opening / closing mechanism 45 is provided at the base ends of the arms 42, 42. The opening / closing mechanism 45 includes a ball screw 45a extending along the rail 41a and a motor 45b that rotationally drives the ball screw 45a.
The arms 42, 42 can be opened and closed by interlocking with each other.

Below the opening / closing chuck 40, an XY stage 20 for suspending the optical fiber preform is provided directly above the heating device 8 (FIG. 1). X
The Y stage 20 is provided on the base 21 so as to be displaceable in one axis direction (the X axis direction in the figure), and is provided on the X stage 22 so as to be displaceable in a direction orthogonal thereto (Y axis direction). Drive mechanisms 24 and 25 provided between the Y stage 23, the base 21 and the X stage 22, and between the X and Y stages 22 and 23, respectively.
By the drive control of 5, the opening / closing chuck 40 can be moved to an arbitrary position in the horizontal direction.

In the holding device 3 of this embodiment, the opening / closing chuck 40 is horizontally placed between the XY stage 20 and the opening / closing chuck 40 in order to stably grip the optical fiber preform regardless of bending and waviness. XY free table 30 for moving in the direction is provided, and
Support mechanisms 43, 43 for swinging the claws 44, 44 are provided at the tip of the opening / closing chuck 40.

FIG. 3 is a diagram showing an example of the structure of the XY free table 30, which is constructed by stacking an X table 32 and a Y table 33 on a base 31 in order. Direct acting ball bearings 34 are provided between the base 31 and the X table 32 and between the X table 32 and the Y table 33, respectively, to enable the opening / closing chuck 40 to move horizontally smoothly and with a light force. ing. Also, XY table 3
The X and Y tables 32 and
Movement prevention means 35, 3 for immobilizing 33
5 are provided. As shown in FIG. 4, the movement preventing means 35 includes a pair of disc pads 36, 36 provided on both sides of a guide rail 34 a forming a linear motion ball bearing 34, an electromagnetic type for opening and closing both disc pads 36, 36, and an air type. The guide rail 34 consists of a drive mechanism (not shown) such as
By sandwiching a from both sides, movement of the XY tables 32 and 33 is restricted.

FIG. 5 is an enlarged view of a configuration example of the support mechanism 43. A first holder 48 rotatably provided inside the extending end of the arm 42 and a first holder 48.
And a second holder 49 provided in front of. A swing shaft 46 projects from the rear of the first holder 48 and is rotatably supported by the arm 42 by the swing shaft 46. Further, the flange 4 is provided on the front surface of the second holder 49 at a predetermined interval.
9b and 49b are formed so as to project, and both flanges 49b and 49b
With the claw portion 44 sandwiched between b and the swing shaft 4
It is rotatably supported by 7. Here, the swing shafts 46 and 47 extend orthogonally to each other, whereby the claw portion 44 can swing in the vertical direction (pitching direction) B and the horizontal direction (yaw direction) A, respectively. . On the other hand, behind the second holder 49, as shown in an exploded view in FIG. 6, four slide shafts 49a are provided in a protruding manner, and these slide shafts 49a are supported by the first holder 48 so as to be able to move forward and backward. ing. A compression coil spring 50 is previously provided on the outer circumference of the slide shaft 49a.
(Elastic member) is installed, and the second holder 4 is always
9 (that is, the claw portion 44) is biased forward.

As with the XY free table 30, the arm 42 and the holder 49 are provided with the claw portion 4.
4, a swinging prevention means for preventing the swinging movement is provided.

7 to 9 are views showing various embodiments of the swinging prevention means.

In the swinging prevention means 51 shown in FIG. 7, the surfaces of the swinging shafts 46 and 47 are processed into flat surfaces at predetermined angles, and the tips of the screws 52 and 52 are pressed against these flat surface portions to make the shafts 46 and 47 The rotation of 47 is restricted.

The swinging prevention means 51 shown in FIG.
A flange 53 is formed on the ends of the swing shafts 46 and 47, and a friction plate 54 is pressed against the flange 53 to prevent rotation. The friction plate 54 is normally separated from the flange 53 by the return spring 55,
By energizing an electromagnet (not shown), it moves forward against the biasing force of the spring 55 and is pressed against the flange 53. As a drive source for the friction plate 54, an air cylinder or the like may be used instead of the electromagnet.

Furthermore, the swinging prevention means 51 shown in FIG.
By rotating the sleeve 57 provided around the ends of the swing shafts 46 and 47, the claws 58 and 5 are formed by a wedge action.
The diameter of 8 is reduced to grip the shafts 46 and 47.

Next, the operation of the above-described optical fiber drawing device 1 will be described.

As shown in FIGS. 10 (1) and 10 (2), when the optical fiber preform 11 is held by the lower holding device 4, the control device 19 (FIG. 1) first moves the movement preventing means 35.
(Fig. 4) is released to make the open / close chuck 40 free to move in the horizontal direction, and then the swinging prevention means 51 (Fig. 8)
Is released so that the claw portions 44, 44 can be swung freely.
Then, the opening / closing mechanism 45 is driven to close the arms 42, 42, and the optical fiber preform 11 is gripped by the claws 44, 44. After the optical fiber preform 11 is gripped, the movement prevention means 35 and the swinging prevention means 51 are activated again to restrain the claw portions 44, 44 from moving. As described above, when the optical fiber preform 11 is held by the lower holding device 4, the opening / closing chuck 40 can be moved horizontally in a free state.
Even if the position of 1 shifts from the original position due to bending or undulation, the claws 44, 44 always move to the optimum position and come into contact with the surface of the optical fiber preform 11, so that It can be held as it is without shifting the position. Moreover, since the impact at the moment when the claw portion 44 contacts the optical fiber preform 11 is alleviated, the preform 11 is not vibrated. Further, by setting the claw portions 44, 44 in a swingable state, the optical fiber preform 11 can be grasped as it is, even if the surface shape or verticality thereof is slightly displaced. 11
The vibrations and displacements that occur in the are reduced as much as possible.

Further, as shown in FIGS. 10 (2) and (3), the upper holding device 3 is released from the state in which the optical fiber preform 11 is held by the upper and lower holding devices 3 and 4. When the optical fiber preform 11 is detached by means of the optical fiber preform 11, the movement preventing means 35 and the swinging preventing means 5 are provided as described above.
In the state where 1 is released, the opening / closing mechanism 45 is driven to move the arm 4
Open 2, 42. As a result, at the moment when the claw portion 44 separates from the optical fiber preform 11, the optical fiber preform 11 is smoothly separated without causing axis deviation or vibration.

Further, as shown in FIGS. 10 (4) to 10 (6),
When a new optical fiber preform 12 is welded onto the optical fiber preform 11 and the lower holding device 4 is separated from the integrated optical fiber preform 13,
In the same manner as described above, the claw portions 44, 44 are smoothly separated from the optical fiber preform 13 and the optical fiber preform 13 does not vibrate or misalign.

During the operations (1) to (6) described above, the control device 19 determines the holding device 3, based on the signal from the sensor 9.
The XY stage 20 of No. 4 is moved so that the optical fiber preform 11 is always positioned at the center of the upper seal cup 8a of the heating device 8.

As described above, according to this embodiment, even if the optical fiber preform 11 is bent or undulated, the claw portions 44 and 44 can always hold and release the optical fiber preform 11 in the optimum position and posture. The preform 11 can be smoothly supplied to the heating device 8 without any positional fluctuation or vibration. Therefore, the optical fiber preform 1
It is possible to reliably prevent the collision of 1 and 12 with the upper seal cup 8a of the heating device 8 and the displacement of the optical fiber 14 during drawing. Moreover, since the optical fiber preform 11 can always be gripped in the center of the claw portions 44, 44, the optical fiber preform 11 can be gripped with a sufficient gripping force, and should the optical fiber preform 11 fall, etc. Can be prevented.

Further, according to this embodiment, the first and second
The claw portion 44 is held via the two holders 48 and 49 of the compression coil spring 5 between the holders 48 and 49.
Since 0 is provided to urge the claw portion 44 forward, the impact when the claw portion 44 comes into contact with the outer periphery of the optical fiber preform can be absorbed by the compression coil spring 50, and the impact at the time of gripping and opening is secured. It can be softened further.

Since the XY stage 20 is moved based on the detection signal from the sensor 9 and the optical fiber preform is always positioned at the center of the heating device 8, the optical fiber preform 13 after welding is placed on the heating device 8. The optical fiber 14 collides with the seal cup 8a or the lower seal cup 8a
It is possible to reliably prevent contact with b.

[0041]

In summary, according to the present invention, the following excellent effects are exhibited.

(1) Since it is possible to suppress the positional fluctuation of the optical fiber preforms when gripping and releasing the optical fiber preforms, it is possible to smoothly supply a plurality of optical fiber preforms into the heating device. Become.

(2) The optical fiber preform can be gripped with a sufficient gripping force.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an optical fiber drawing device.

FIG. 2 is a schematic perspective view showing a configuration example of a holding device applied to the optical fiber drawing device of the present invention.

FIG. 3 is an XY applied to the optical fiber drawing device of the present invention.
It is an exploded perspective view showing an example of composition of a free table.

FIG. 4 is a diagram showing a configuration example of movement prevention means provided on an XY free table.

FIG. 5 is an enlarged view showing a configuration example of a support mechanism applied to the optical fiber drawing device of the present invention.

FIG. 6 is an exploded perspective view of a support mechanism.

FIG. 7 is a diagram showing an example of a swinging prevention means provided in a support mechanism.

FIG. 8 is a view showing another embodiment of the swinging prevention means provided in the support mechanism.

FIG. 9 is a view showing still another embodiment of the swinging prevention means provided in the support mechanism.

FIG. 10 is a diagram showing a series of operations of the optical fiber drawing device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical fiber drawing device 2 Guide bar 3 Upper holding device 4 Lower holding device 7 Welding device 8 Heating device 9 Sensor 20 XY stage 30 XY free table 35 Movement prevention means 40 Open / close chuck 42 Arm 43 Support mechanism 44 Claw part 46, 47 Swing shaft 50 Compression coil spring 51 Swing prevention means

Front Page Continuation (72) Inventor Shigenori Nemoto 5-1-1 Hidaka-cho, Hitachi-shi, Ibaraki Hitachi Cable Co., Ltd. Hidaka Plant (72) Hideo Matsuo 5-1-1 Hidaka-cho, Hitachi-shi, Ibaraki No. 1 Hitachi Cable Co., Ltd. Hidaka Plant (72) Inventor Tetsuro Nakagawa 5-1-1 Hidaka Town, Hitachi City, Ibaraki Hitachi Cable Co., Ltd. Hidaka Plant

Claims (3)

[Claims] 1. An optical fiber preform gripped by a holding device is sent to a heating device by descending of the holding device and melt-drawn, and the optical fiber preform is provided on another side of the holding device. In the optical fiber drawing method of gripping with the device and then welding the lower end of the optical fiber preform newly gripped with the holding device to the upper end of the optical fiber preform, the holding device is opened and closed around a predetermined position. A pair of arms that can be smoothly moved horizontally is provided, and a claw portion that engages with an optical fiber preform is provided inside the arms so that the arm and the claw portion can be moved and swung freely. In this state, the arm is opened and closed to grip and release the optical fiber preform, and then the arm and the claw are moved. A method for drawing an optical fiber, characterized by immovably restraining. 2. An upper and lower holding device capable of suspending and holding the optical fiber preforms above the heating device so as to continuously feed a plurality of optical fiber preforms into the heating device. In the optical fiber drawing device capable of being provided, a pair of arms that open and close the upper and lower holding devices around a predetermined position, and a pair of claw portions that can engage with the optical fiber preform surface from both sides. , An XY free table for smoothly moving the arm in the horizontal direction, and a support mechanism for swingably supporting the claw portions inside the both arms, respectively. An optical fiber drawing device comprising means for preventing movement of the arm and means for preventing swinging of the claw portion. 3. The support mechanism rotatably supports the first holder rotatably supported inside the arm and the claw portion and is provided in front of the first holder movably back and forth. 3. The optical fiber drawing device according to claim 2, further comprising a second holder and an elastic member provided between the first and second holders and biasing the second holder forward. .