JP4913766B2 - Rotating support rod holding device and rotating support rod holding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retaining device of a rotation supporting rod capable of accurately, stably, and inexpensively adjusting an axis of the rotation supporting rod, when the other end of the rotation supporting rod to which a base element or a processed element are coupled so as to make its axis match at one end is equipped to a rotating mechanism. <P>SOLUTION: In the retaining device of the rotation supporting rod, the other end of the rotation supporting rod 2 to which the processed element is coupled so as to make its axis match at one end is equipped to the rotating mechanism 3. The retaining device of the rotation supporting rod 2 comprises at least three rectangular platy elements 10 longitudinally attached in an outer peripheral direction of the other end of the rotation supporting rod 2 and so as to make an inner surface contact in an axial direction of the rotation supporting rod 2; and a fastening tool 4 equipped to the rotating mechanism 3, freely moving in a center direction of the rotation supporting rod 2, and fastening and pressing an outer surface of the platy element 10 longitudinally attached on the outer surface of the rotation supporting element 2. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a rotating support rod holding device and a rotating support rod holding method used to guide an optical fiber preform while rotating it in a furnace core tube and to perform heat treatment such as dehydration and sintering.

  For example, as one of the processes for manufacturing an optical fiber, there is a process of putting a porous optical fiber base material (hereinafter simply referred to as a base material) into a heating furnace, performing heat treatment, dehydrating and vitrifying. This heat treatment process is performed by attaching a long rotating support rod to a rotating mechanism installed in a lifting machine installed above the heating furnace, and further suspending a long base material on the tip of the rotating support rod. .

At this time, the axis of the rotating support rod needs to coincide with the axis of the core tube of the heating furnace with high accuracy.
Otherwise, if the base material is attached to the lower end of the rotating support rod, the rotating support rod is rotated by the rotating mechanism, and this is gradually lowered into the reactor core tube, the base material will be misaligned. This is because the base material cannot be uniformly dehydrated and vitrified.

The case where a rotation support rod is specifically attached to a rotation mechanism will be described with reference to FIGS. 7 is a schematic side view showing a state in which the base material is heat-treated in a heating furnace, FIG. 8 is a plan view of the positional relationship between the furnace core tube and the rotating support rod, and FIG. 9 is an axial center of the core tube from the side direction. It is the simplified view which shows the state which looked at the shaft center of the rotation support rod.
As shown in FIG. 7, the heating furnace 8 includes a furnace core tube 5 and a heater 6. When heat-treating the base material 1, first, one end of the rotation support rod 2 is inserted into the holding portion of the rotation mechanism 3, and this is tightened with, for example, three or four directions with a fastening tool 4 made of a bolt or the like. The rotation support rod 2 is fixed to the rotation mechanism 3. Next, the upper end of the base material 1 is connected to the other end of the rotation support rod 2.

By the way, in the holding part of the rotation mechanism, for example, when the rotation support rod 2 is fixed with the four fasteners 4, the center O ₅ of the core tube ₅ and the rotation support rod 2 are connected as shown in FIG. at the same time to match the center O _2, as shown in FIG. 9, over the axial direction, so that the axis P ₂ of the axial center P ₅ and the rotary support rod 2 of the core tube 5 is identical, i.e., the angle of Each fastener 4 is put in and out so that the shift θ becomes zero. Since the core tube 5 is normally are installed almost vertically, the rotation support rod of axis deviation angle P ₂ and the axis P ₅ of the core tube 5 theta 2, the axis P ₂ of the rotating support rod 2 This is almost the same as the amount of deviation in the vertical direction. Further, by connecting the two so that the axis of the base material and the axis of the rotary support rod 2 coincide with each other, the axis of the base material 1 and the axis of the core tube 5 coincide with each other. After adjusting in this way, the base material 1 is inserted into the core tube 5 at a constant speed as indicated by the downward arrow while rotating the rotation support rod 2 at a constant rotational speed by the rotation mechanism 3. Is heat-treated under predetermined heating conditions over its entire length.

  In such a heat treatment process, if the base material 1 becomes larger and becomes longer like nowadays, it is inevitably necessary to make the rotary support rod 2 longer. For this reason, if the rotating support rod 2 is rotated and lowered while the base material 1 is connected to the rotating support rod 2 even if the axial center shake of the core tube 5 and the rotating support rod 2 is adjusted to substantially zero, There arises a problem that the runout occurs at the lower end portion of the base material 1 due to the deviation of the center of gravity of the material 1 or the lack of processing accuracy of the rotation support rod 2. When the shaft center is shaken, the heat treatment of the base material 1 becomes uneven, and the quality becomes non-uniform so that a high-quality optical fiber cannot be obtained. In the worst case, the outer surface of the base material 1 and the inner surface of the core tube 5 may come into contact with each other at the lower end of the base material 1, and one or both may be damaged.

  Therefore, in order to solve such a problem, for example, as shown in Patent Document 1, a holding device that connects a base material and a rotation support rod has also been proposed. Specifically, in the invention disclosed in Patent Document 1, as shown in FIG. 7 and FIG. 9 attached to Patent Document 1, the base material side is connected to the connecting portion with the base material of the rotation support rod. A holding member for inserting the end of each of the bolts is provided, and for example, three bolt holes are provided on each of the holding members on at least two cross sections orthogonal to the axial direction of the base material. Bolts are taken in and out in the cross section so that the axis center of the base material and the rotation support rod can be adjusted.

JP 2000-053438 A

By the way, in the holding member disclosed in Patent Document 1, since the shaft center can be adjusted at two or more locations in the axial direction of the base material, the shaft of the base material can be used rather than the conventional one adjusted. It is considered that the shaft and the rotation support rod can be accurately aligned with each other. In particular, it is presumed that the inclination angles of the two axes can be adjusted more accurately because they can be adjusted at two locations in the longitudinal direction of the shaft.
However, even in this method, as can be seen from FIGS. 7 and 9 attached to Patent Document 1, it is the tip surfaces of the three bolts that press the outer surface of the end portion of the base material. In other words, the tip end of any one bolt is only contacted with the tip of the base material at the tip of three bolts (total of six in two axial directions) and pressed to position the shaft center. There is a possibility that the shaft center of the base material and the shaft center of the rotation support rod may be slightly shifted only by changing the contact state of the surface. That is, it is considered that a situation where the alignment of the axis of the base material and the axis of the rotation support rod can be easily and stably performed has not been achieved.

In addition, in the invention shown in Patent Document 1, when trying to match the base material and the axis of the rotation support rod more accurately, the inner surface for holding the base material of the holding member described above, that is, It is necessary to increase the length of the groove 22A. However, in the case of machining with a lathe or the like, rotation blur becomes large at one end of a long rotation support rod, and it is difficult to perform machining with high accuracy.
In particular, the longer the groove 22A is made, the more difficult it is to process, and there is also a problem that the axis of the rotation support rod and the axis of the groove 22A are liable to shift. In other words, there is also a problem that if the groove 22A of the holding member of the terminal is made highly accurate, the processing cost of the rotating support rod will inevitably increase.
In addition, as described above, adjusting on at least two cross sections in the axial direction means that at least 6 bolts must be taken in and out at the same time. However, there is also a problem that it takes an adjustment time as the number of bolts to be adjusted increases.

By the way, the invention disclosed in Patent Document 1 relates to the connection between the base material and the rotation support rod. As can be seen from FIG. Since the distance from the tip position of the mechanism 3 to the lower end of the base material 1 is longer than the distance from the lower end of the rotation support rod 2 to the lower end of the base material 1 in the connection between the base material 1 and the rotation support rod 2, there is a problem. Is big.
However, Patent Document 1 does not teach anything about the connection between the rotation support rod and the rotation mechanism.
Incidentally, such a problem is a big problem that occurs even when a rotation support rod having a base connected to one end in a semiconductor manufacturing apparatus is attached to a rotation mechanism.

  In view of the above-described problems, the object of the present invention is to provide a shaft for the rotation support rod when the other end of the rotation support rod to which the base body or the object to be processed is connected so that the axis coincides with the one end. An object of the present invention is to provide a rotation support rod holding device that can perform center adjustment more accurately and easily and that is inexpensive, and in addition, to provide a method for holding this rotation support rod.

In order to achieve the above object, a rotating support rod holding device according to claim 1 of the present invention is a holding device for a rotating support rod in which the other end of the rotating support rod connected to one end of the substrate or the object to be processed is attached to the rotating mechanism. In the apparatus, the rotation support rod holding device is arranged at substantially equal intervals along the outer circumferential surface of the other end of the rotation support rod so that the inner surface is in parallel contact with the axial direction of the rotation support rod. At least three rectangular plates attached vertically, and the plate attached to the rotation mechanism, movable in the center direction of the rotation support rod, and vertically attached to the outer surface of the rotation support rod A fastening tool for fastening and pressing the outer surface of the plate-like body, wherein the fastening tool is a bolt, and the front end of the bolt presses substantially the center of the outer surface of the plate-like body. It is what.

According to the rotating support rod holding device according to claim 1, the outer surface of the rotation support rod is arranged along the circumferential direction of the rotation support rod and is vertically attached. The rotation support rod can be easily attached to the holding portion of the rotation mechanism by tightening with a fastening tool such as a bolt attached to the rotation mechanism via a rectangular plate-like body.
Further, in this way, the rectangular plate-like body is vertically attached to the outer surface of the rotation support rod, that is, the plate is attached in such a state that the long side direction of the plate-like body is parallel to the axial direction of the rotation support rod. Since the outer surface of the rod-like body is pressed by a fastener attached to the rotation mechanism, the force pressed by the fastener is equal to the length of the plate-like member with respect to the axial direction of the rotation support rod. As a result, the shake of the axis of the rotation support rod is restricted by the amount corresponding to the length of the plate-like body.

To explain more clearly, the rotation support rod is pressed in multiple stages in the axial direction to control the shake of the shaft center, and the influence of the deviation of the center of gravity of the base material 1 and the lack of processing accuracy of the rotation support rod 2 is affected. It becomes difficult to receive, and the angle deviation θ of the axis of the rotating support rod with respect to the axis of the processing apparatus such as the core tube can be reduced. Thereby, when a to-be-processed body like a base material is connected to the lower end of a rotation support rod, the shake of the shaft center of a processing apparatus and the shaft center of a to-be-processed body can be made small compared with the past.
Moreover, since the members used are only at least three plate-like bodies, there is an advantage that the processing is easy and can be obtained at low cost.

According to a second aspect of the present invention, there is provided the rotary support rod holding device according to the first aspect, wherein the bolt has a spherical tip.
According to a third aspect of the present invention, there is provided the rotary support rod holding device according to the first or second aspect , wherein the plate-like body is in surface contact with the outer surface of the rotary support rod. It has a possible curved groove.
According to the inventions of claims 2 and 3 as described above, the outer surface of the rotation support rod can be more stably pressed and the shake of the shaft center can be restricted. As a result, for example, it is easier to align the axis of the rotating support rod and the axis of the processing apparatus such as the core tube, and the amount of deviation between the axis of the workpiece such as the base material and the axis of the processing apparatus such as the core tube is reduced. Can be small. Furthermore, the state can be maintained stably for a long time.

Furthermore, according to the fourth aspect of the present invention, there is provided the rotation support rod holding method according to the present invention, wherein the rotation support rod is connected at one end to the other end of the rotation support rod to which the substrate or the object to be processed is connected. In addition, at least three rectangular plates are vertically attached so that the inner surfaces thereof are in contact with each other in the axial direction of the rotation support rod, and then the approximate center of the outer surfaces of these plate-like members is disposed at the rotation mechanism. The rotation support rod is attached to the rotation mechanism by being clamped and pressed with the tip of a bolt that is mounted on the rotary support rod and is movable in the center direction of the rotation support rod.

According to the method of holding the rotating support rod according to claim 4 , the rectangular support, for example, three plate-like bodies are vertically attached to the outer surface of the rotating support rod, and this is the same as the conventional number. By simply tightening and adjusting with a fastening tool such as a bolt, it is possible to reduce the shake of the axis of the rotating support bar on which the base body or the object to be processed is mounted at one end, and to easily prepare for mounting the rotating support bar.

Furthermore, the invention according to claim 5 of the present invention is characterized in that, in the holding method of the rotary support rod according to claim 4, the tip of the bolt positioned substantially at the center of the outer surface of the plate-like body is a spherical surface. To do.
Furthermore, the invention according to claim 6 of the present invention is characterized in that, in the method for holding a rotating support rod according to claim 4 or 5 , the object to be processed is a porous optical fiber preform.
According to the rotating support rod holding method according to claims 5 and 6 , the heat treatment of the long optical fiber preform is uniformly performed in the longitudinal direction of the preform. It can be done reliably. Therefore, a base material with stable quality can be obtained in the longitudinal direction, and an optical fiber with excellent quality can be manufactured with high yield.

  As described above, according to the present invention, when the other end of the rotation support rod having one end connected to the base body or the object to be processed is attached to the rotation mechanism, the axis of the rotation support rod can be adjusted more accurately and easily. In addition, an inexpensive rotary support rod holding device can be provided. In addition, a method for holding the rotating support bar can be provided.

Embodiments of the rotation support rod holding device and the rotation support rod holding method of the present invention will be described in detail below with reference to the drawings. In the following description, the same components as those in FIGS. 7 to 9 described above are denoted by the same reference numerals, and detailed description thereof is omitted.
FIG. 1 is a partial schematic side view showing a state in which a rotary support rod 2 is mounted on a rotary mechanism 3 as a holding device for a rotary support rod according to the present invention.
As shown in FIG. 1, a major feature of the rotation support rod holding device of the present invention is that the object 1 to be processed, for example, a base material for an optical fiber, omitted in FIG. At the other end (upper end in FIG. 1) of the rotating support rod 2 to be connected, the rotation support rod 2 is rotated through a rectangular plate-like body 10 vertically attached at substantially equal intervals in the circumferential direction of the outer surface thereof. 3 is attached to the holding portion that holds the rotation support rod 2 by being fastened by the fastening tool 4.

Incidentally, in this example, three rectangular and identical plate-like bodies 10 are vertically attached to the outer peripheral surface of the rotation support rod 2 at equal intervals of 120 degrees, and this is attached to the rotation mechanism 3 in the circumferential direction. It is tightened with a fastener 4 composed of three bolts mounted at equal intervals of 120 degrees. That is, the rotation support rod 2 is fastened with the fastening tool 4 via the plate-like body 10 and fixed to the rotation mechanism 3.
Here, the vertical attachment means that the long side direction of the plate-like body 10 is parallel to the axial direction of the rotation support rod 2 and the inner surface thereof is arranged so as to contact the outer surface of the rotation support rod 2. .

  As shown in FIG. 1, a rectangular plate-like body 10 is vertically attached to the outer surface of the rotation support rod 2, and in this state, the outer surface of the plate-like body 10 is clamped and pressed by a fastening tool 4 attached to the rotation mechanism 3. Therefore, the force pressed by the fastening tool 4 acts over a length corresponding to the length of the plate-like body 10 with respect to the axial direction of the rotary support rod 2. Shaking of the shaft center of the rotation support rod 2 is regulated by the amount corresponding to the length.

That is, the same effect as that in which the rotation support rod 2 is pressed in multiple stages in the axial direction and the shake of the shaft center is restricted is brought about, and the vertical deviation θ of the rotation support rod 2 can be reduced. This will be described with reference to an example of the base material. Since the shift θ of the angle between the axis of the core tube 5 and the axis of the rotary support rod 2 can be reduced, the shift between the axis of the core tube 5 and the center angle of the base material 1 can be reduced. Can be made smaller than before.
Moreover, since the member used is merely the addition of about three plate-like bodies 10 as compared with the conventional member, it is easy to process, and therefore has an advantage that it can be obtained at low cost. Further, since the number of the fasteners 4 used is the same as the conventional one, there is no fear that the adjustment time is longer than that of the invention disclosed in Patent Document 1.

FIG. 2 is a plan view and a side view of the plate-like body 10. A counterbore portion 11 is provided at the approximate center of the plate-like body having a length L, and the bolt 4 is positioned at the center of the fastener 4 in this portion, in this example, the counterbore portion 11. . Of course, there is no problem even if the positions where the bolts are tightened and pressed are slightly deviated, so it is not always necessary to provide the counterbore portion 11.
By the way, the inner surface of the plate-like body 10, that is, the surface in contact with the outer surface of the rotary support rod 2 is equal to the radius R of the rotary support rod 2 so that the outer surface of the rotary support rod 2 can be brought into wider surface contact. A curved groove 12 having a radius of curvature R or a slightly larger radius of curvature is formed. Of course, for example, when L is large, it is not necessary to provide the curved groove 12. However, if the curved groove 12 is provided, it is easy to attach the plate-like body 10 vertically to the rotation support rod 2 when attaching the rotation support rod 2 to the rotation mechanism 3, and the operation is facilitated. There is an advantage that the rotation support rod 2 can be gripped more reliably.

  FIG. 3 is an example of the fastener 4 shown in FIG. 1, which is a bolt. However, the tip portion 9 is processed into a spherical shape. The reason is that the rotary support rod 2 is fastened with the bolts via the plate-like body 10 and the degree of tightening of the three fasteners 4 is adjusted to adjust the axis of the rotary support rod 2 and the axis of the core tube 5. Is adjusted so that the tip of the fastener 4 is spherical and the contact area between the tip of the fastener 4 and the plate-like body 10 does not change depending on the degree of rotation. This is because a force that rotates the body 10 is less likely to be loaded. That is, it becomes easier to adjust the axis. Of course, it goes without saying that a commercially available bolt can be used as it is as the fastener 4.

4 shows a state where the rotation support rod 2 is mounted on the rotation mechanism 3, and is a cross-sectional view taken along the line AA of FIG. 1. FIG. 5 shows a mounting portion of the holding device showing a state where the rotation support rod 2 is mounted. FIG. 2 is a partially enlarged side view of FIG.
As shown in FIGS. 4 and 5, the rotation support rod 2 is held by the holding portion of the rotation mechanism 3 so that the axis of the core tube 5 (not shown) coincides with the axis. The rotation support rod 2 is three fasteners 4 that are positioned at equal intervals of 120 degrees in the circumferential direction of the rotation support rod 2, and is also vertically arranged on the outer surface of the rotation support rod 2 at equal intervals of 120 degrees in the circumferential direction. The outer surfaces of the three attached plate-like bodies 10 are respectively clamped and pressed.
In the actual adjustment of the shaft center, a dial gauge is set on the rotation support rod 2, the rotation support rod 2 is rotated to measure the shake of the shaft center, and the measured shake of the shaft center is a predetermined value. The three fastening tools 4 are put in and out to adjust the amount of tightening so that the shaft centers are aligned.

By the way, the longer the length L of the plate-like body 10 vertically attached to the outer surface of the rotary support rod 2, the smaller the shake of the axis can be reduced even when the rotary support rod 2 is rotated. In the example of the base material, the smaller the angle difference θ between the cores of the core tube 5 and the rotary support rod 2, the smaller the shake between the base material shaft and the core tube axis. However, if the length is too long, problems such as difficulty in vertically attaching the plate-like body 10 to the outer surface of the rotation support rod 2 and a short effective stroke occur. Therefore, the length L of the long side of the plate-like body 10 is reduced. What is necessary is just to design considering the length of the to-be-processed object 1 and the rotation support rod 2, the allowable amount of shaft center shake, and the like.
Further, the horizontal width (length W in the short side direction) of the plate-like body 10 is such that the curved groove 12 contacts at 50% or more of the radial direction of the rotary support rod 2 from the viewpoint of more reliably gripping the rotary support rod 2. It is preferable to set so that the curved groove 12 contacts at 70% or more of the radial direction of the rotary support rod 2.
Moreover, the material of the plate-like body 10 is not particularly limited. For example, a metal material can be used, and lightweight aluminum is preferable.

In the above embodiment, three rectangular plate-like bodies 10 are vertically attached to the outer peripheral surface of the rotation support rod 2, but three or more, for example, four plate-like bodies 10 are 90 degrees. The outer peripheral surface of the rotation support rod 2 may be attached at regular intervals.
Further, only the example of the object 1 to be processed such as a base material is shown as being connected to one end of the rotation support rod 2, but the rotation support rod holding device of the present invention is, for example, at one end of the rotation support rod 2. The present invention can also be applied to an apparatus for connecting a disk-shaped substrate and growing a single crystal for a semiconductor or the like on the surface of the disk-shaped substrate. That is, the present invention is a device in a form of rotating the rotary support rod 2 and moving the rotary support rod 2 in the axial direction, and the shake of the axial center of the rotary support rod 2 must be kept extremely small. Applicable to various devices.

Hereinafter, the example which performed vitrification of the optical fiber preform using the holding device of the rotation support bar of the present invention is described.
[Example]
The optical fiber preform was vitrified using the rotating support rod holding device of the present invention shown in FIG.
The rotation support rod 2 is attached to a holding portion that holds the rotation support rod 2 of the rotation mechanism 3 via a rectangular plate-like body 10 shown in FIG. 2 that is vertically attached at substantially equal intervals in the circumferential direction of the outer surface thereof. It was fastened with the fastening tool 4 shown in FIG. The rotation support rod 2 has a length of about 4 m and an outer diameter of about 50 mm. The plate-like body 10 has a long side length L of about 150 mm and a short side length W of about 35 mm, and a curved groove 12 having a radius of curvature R substantially equal to the radius R of the rotary support rod 2 is rotationally supported. What was formed in the surface which contacts the stick | rod 2 was used.
The angle between the axis of the core tube 5 and the axis of the rotary support rod 2 when the base material 1 is not connected to the rotary support rod 2 and the rotary support rod 2 is rotated at a fixed position without moving up and down. The deviation θ was adjusted to zero.

[Comparative example]
An optical fiber preform having the same size as that of the example was vitrified in the same manner as in the example except that the rotating support rod 2 was held using only three bolts having a horizontal tip surface.
The angle between the axis of the core tube 5 and the axis of the rotary support rod 2 when the base material 1 is not connected to the rotary support rod 2 and the rotary support rod 2 is rotated at a fixed position without moving up and down. The deviation θ was adjusted to zero.

The optical fiber preforms manufactured in Examples and Comparative Examples were drawn, and the core eccentricity of the obtained optical fibers was measured. The results are shown in FIG. In FIG. 6, the horizontal axis indicates the position of the optical fiber preform in the longitudinal direction, the right side is the lower end when vitrified, and the left side is the upper end when vitrified.
As shown in FIG. 6, in the comparative example, the core eccentricity on the lower end side during vitrification was large, whereas in the example, the core eccentricity was stable and good in the longitudinal direction.

  As described above, according to the present invention, when the other end of the rotation support rod, to which the base body or the object to be processed is connected so that the axial center coincides with one end, is attached to the rotation mechanism, the shaft of the rotation support rod It is possible to easily and accurately adjust the center, and to provide an inexpensive rotating support rod holding device, and in addition, it is possible to provide a method for holding the rotating support rod.

FIG. 3 is a partial schematic side view showing a state in which the rotation support rod is mounted on a rotation mechanism, which is an embodiment of the rotation support rod holding device of the present invention. It is the top view and side view of a plate-shaped body in the holding | maintenance apparatus of the rotation support rod of this invention. It is a side view which shows an example of the fastener in the holding | maintenance apparatus of the rotation support bar of this invention. FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, showing a state where the rotary support bar is mounted on the rotary mechanism in the rotary support bar holding device of the present invention. It is a partial expanded side view of the mounting part of the rotation support bar in the holding device of the rotation support bar of the present invention. It is the graph which compared the core eccentricity of the optical fiber obtained by the Example and the comparative example. It is a schematic side view which shows the state which heat-processes a porous optical fiber preform with a heating furnace. It is the top view which looked at the positional relationship of the core tube in FIG. 7 and a rotation support rod from the top. FIG. 8 is a simplified diagram showing a state in which the axis of the core tube and the axis of the rotation support rod are viewed from the side surface direction in FIG. 7.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 To-be-processed object 2 Rotating support rod 3 Rotating mechanism 4 Fastening tool 5 Furnace core tube 6 Heater 8 Heating furnace 9 Fastening tool tip part 10 Plate-like body 11 Counterbore part 12 Curved groove

Claims (6)

In the rotation support rod holding device in which the other end of the rotation support rod to which the substrate or the object to be processed is connected to one end is attached to the rotation mechanism.
The rotating support rod holding device comprises:
At least three rectangular plates vertically attached so as to be in contact with each other in the axial direction of the rotary support rod at substantially equal intervals along the outer circumferential surface of the other end of the rotary support rod. And a clamp that is attached to the rotation mechanism, is movable in the center direction of the rotation support rod, and clamps and presses the outer surface of the plate body vertically attached to the outer surface of the rotation support rod; , has a,
The fastening device is a bolt, and the rotating support rod holding device is characterized in that the front end of the bolt presses the approximate center of the outer surface of the plate-like body .   2. The holding device for a rotating support bar according to claim 1, wherein a tip of the bolt is a spherical surface. The rotation support rod holding device according to claim 1 or 2 , wherein the plate-like body has a curved groove on its inner surface that can come into surface contact with the outer surface of the rotation support rod. The other end of the rotating support rod to which the substrate or the object to be processed is connected at one end is contacted at substantially equal intervals along the circumferential direction of the rotating support rod, and the inner surface thereof is parallel to the axial direction of the rotating support rod. At least three rectangular plate-like bodies are vertically attached to each other, and then approximately the center of the outer surface of these plate-like bodies is attached to the rotation mechanism and is movable toward the center of the rotation support rod . A method of holding a rotating support bar, wherein the rotating support bar is attached to the rotating mechanism by being clamped and pressed at a tip .   5. The method of holding a rotating support rod according to claim 4, wherein a tip of the bolt positioned substantially at the center of the outer surface of the plate-like body is a spherical surface. 6. The method of holding a rotating support rod according to claim 4, wherein the object to be processed is a porous optical fiber preform.

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