JP2001019458A - Tool and method for breaking optical fiber preform rod - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently cut a rod with a flat breaking surface at an adequate length with simple manipulation by mounting a disk blade which has abrasive grains on its front surface and is provided with radial grooves on the front and rear surfaces of its outer peripheral part at a rotational driving tool. SOLUTION: The optical fiber preform rod breaking tool 1 for putting notches for breaking the optical fiber preform rod to the rod is formed by mounting the disk blade 2 which has the abrasive grains 5 on its front surface and is provided with the radial grooves 3 on the front and rear surfaces of its outer peripheral part 4 at the rotational driving tool 5. The abrasive grains 5 are preferably diamond abrasive grains. The grooves 3 of the disk blade 2 are connected at the outer peripheral part. The grooves 3 efficiently discharge the chips produced when the notches are put to the preform rod. The notches are formed by pressing the outer peripheral part 4 of the disk blade 2 onto the flank circumference of the optical fiber preform rod while the disk blade 2 is kept rotated. The rod is then broken by exerting impact thereto by using a hammer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool and a method for breaking a preform rod, which is a material of an optical fiber, to an appropriate length.

[0002]

2. Description of the Related Art An optical fiber is obtained by stretching an optical fiber preform preform, which is dehydrated and transparently vitrified by sintering a porous glass preform mainly composed of quartz glass, to obtain an optical fiber preform rod. This is cut to an appropriate length and drawn.

Conventionally, an optical fiber preform rod that has been drawn by pulling down an optical fiber preform base material that has passed through a heating furnace, is pinched and rotated by a pipe cutter having granular diamond, and is then wound with a hammer. It was broken by hitting it with an impact. However, since the rod is broken obliquely with respect to the axis of the rod, or irregularities are generated in the broken surface, both ends of the broken rod must be blown with a flame to be smoothed, and the operation is complicated. However, there is a problem that the glass in the fusing portion is largely lost and the yield is low.

In recent years, preform base materials and rods have been increased in diameter in order to improve the productivity of optical fibers. Since the rod had a large diameter, it was robust, so that it could not be broken even if it was scratched with a pipe cutter and subjected to impact. For this reason, the flame must be blown, which is inefficient.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is used for efficiently breaking an optical fiber preform rod with an appropriate length and high quality by a simple operation. It is an object to provide a tool to be used and a breaking method.

[0006]

The optical fiber preform rod breaking tool of the present invention, which has been made to achieve the above object, will be described below with reference to the drawings corresponding to the embodiments.

Optical fiber preform rod breaking tool 1
As shown in FIG. 1, is a tool for making a cut for breaking an optical fiber preform rod, which has abrasive grains 5 on the surface and has radial grooves 3 on the front and back surfaces of the outer peripheral portion 4. The disk blade 2 is mounted on the rotary drive 6. The abrasive grains 5 can be suitably implemented by being diamond abrasive grains.

The grooves 3 on the front and back surfaces are connected at the outer periphery. The groove 3 efficiently discharges chips generated when the disk blade and the rod are brought into contact with each other to make a cut. The material of the disk blade is preferably chromium-molybdenum steel.

As shown in FIG. 1, a method of breaking an optical fiber preform rod has abrasive grains 5 on its surface,
While rotating the disk blade 2 having the radial grooves 3 on the front and back surfaces of the optical fiber preform rod 15, as shown in FIG.
After the notch 17 is formed by pressing the outer peripheral portion 4 of the base member, an impact is applied to the side surface circumference 16 by the hammer 18.

The notch 17 is formed on the side circumference 16 of the rod 15.
If provided on the same surface perpendicular to the axis of the rod, the rod 15 can be broken along the side surface circumference 16 without generating irregularities when an impact is applied.

In this optical fiber preform rod breaking method, the notch 17 is an arc having a length of at least １ ／ of the entire circumference of the side circumference 16 of the rod 15. It can be suitably implemented by being given in the vicinity A in the middle of an arc without a circle. The notch 17 is more preferably an arc having a length equal to or more than １ ／ of the entire circumference of the side circumference 16. If the distance is out of this range, the fractured surface may have irregularities or may have an inclined cross section with respect to the axis of the rod when fractured. Preferably, the direction of impact is perpendicular to the contact surface of the rod. Examples of the hammer that gives an impact include an iron hammer, and among them, the keren hammer 18 having a sharp tip shown in FIG. 2 is preferable.

It is preferable that the abrasive grains 5 are diamond abrasive grains, since the cut can be made easily and efficiently.

The reason that the fracture surface becomes perpendicular and flat with respect to the axis when fractured by this method is because the shock wave propagates uniformly to the notch 17 which is thicker and deeper than the flaw caused by the conventional pipe cutter, and is symmetrical near the notch. It is presumed that this is to induce cracks. The cut 17 may be provided on the entire circumference of the side circumference 16.

According to the optical fiber preform rod breaking method of the present invention, the optical fiber preform rod can be efficiently and efficiently broken at a suitable length by a simple operation.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a perspective view of an optical fiber preform rod breaking tool to which the present invention is applied. As shown in FIG. 1, the optical fiber preform rod breaking tool 1 has a disk blade 2. The disk blade 2 has abrasive grains 5 of industrial diamond on its outer peripheral surface.
Have radial grooves 3 on the front and back surfaces. Front and back grooves 3
Are connected at the outer edge of the outer peripheral portion 4. The axis of the disk blade 2 is connected to a rotary driving tool 6, for example, a motor of a disk grinder.

FIG. 2 is a schematic view of an apparatus used for breaking an optical fiber preform. The optical fiber preform preform 10 is inserted into a heating furnace 11. A threaded rod 13 is screwed into a gripper 12 that is pulling down while holding the base material 10 below the heating furnace 11, and a guide rod 14.
Is inserted. The optical fiber preform rod 15 formed by pulling down the gripper 12 penetrates the fall prevention ring 19. Below that, a table 20 for mounting the broken and separated rod is arranged with a slight gap from the lower end of the rod 15. A screw rod 21 is screwed into a pedestal 23 to which the mounting table 20 and the fall prevention ring 19 are fixed, and a guide rod 22 is inserted.

The optical fiber preform rod is broken as follows. Optical fiber preform base material 10
Is softened while being inserted into the heating furnace 11, and the gripper 12 is pulled down by the rotation of the screw bar 13, whereby the optical fiber preform rod 15 is obtained. By rotating the screw 21
While maintaining a gap between the lower end of the rod 15 and the separation rod mounting table 20, the pulling speed of the gripper 12, ie, the rod 1
The mounting table 20 is lowered in synchronization with the lowering speed 5.

When the elongated rod 15 reaches a desired length, the disk blade 2 is rotated by driving the motor of the disk grinder 6 to grip the handle 7 of the disk grinder, and the pulling speed of the rod 15 is reduced. The outer peripheral portion 4 of the disk blade 2 is pressed onto the side surface circumference 16 of the rod 15 while being lowered in synchronization with the rotation. Outer peripheral portion 4 of disk blade 2
Is moved along the side circumference 16 of the rod 1 to form a subarc notch 17 having a length １ ／ of the side circumference. The glass swarf generated when the notch 17 is formed is swept out by the groove 3 of the disk blade 2.

The cut 17 on the side circumference 16
When a tapping impact is given to the vicinity A of the middle of the excellent arc with no keel hammer 18, a crack is induced near the cut 17, and the rod 15 is broken along the side circumference 16 by the weight of the rod 15. The rod broken to a desired length falls slightly and rides on the mounting table 20. The mounting table 20 is further moved downward by increasing the descending speed and then stopped, and the broken rod is pulled out of the fall prevention ring 19. By repeating this operation, the rod can be continuously broken. This fractured surface has no irregularities and is a surface perpendicular to the axis. For safety, the outer periphery of the sharp fractured surface may be annealed by a flame.

[0020]

As described above in detail, according to the rod breaking method using the optical fiber preform rod breaking tool of the present invention, the optical fiber preform rod can be appropriately lengthened by a simple operation. Can be efficiently broken. The fracture surface can be a flat, circular cross-section perpendicular to the axis. Further, there is no need to melt-cut the fractured surface, so that productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of an optical fiber preform rod breaking tool to which the present invention is applied.

FIG. 2 is a schematic view showing an example of an apparatus used when performing an optical fiber preform rod breaking method to which the present invention is applied.

[Explanation of symbols]

1 is an optical fiber preform rod breaking tool, 2 is a disk blade, 3 is a groove, 4 is an outer peripheral portion, 5 is a diamond abrasive, 6 is a rotary driving tool, 7 is a handle, 10 is an optical fiber preform base material, 11 is a heating furnace, 12 is a gripping tool, 13 is a screw rod, 14 is a guide rod, 15 is an optical fiber preform rod, 16 is a side circumference, 17 is a cut, 18 is a hammer, 19 is a fall prevention ring, 20 is a separation rod mounting table,
21 is a screw bar, 22 is a guide bar, 23 is a pedestal, and A is an impact position.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B24D 5/12 B24D 5/12 Z B28D 1/04 B28D 1/04 Z (72) Inventor Tadakatsu Shimada Gunma 2-13-1 Isobe, Annaka-shi Shin-Etsu Kagaku Kogyo Co., Ltd. Precision Functional Materials Research Laboratories (72) Inventor Hideo Hirasawa 2-3-1-1 Isobe, Annaka-shi Gunma Prefecture Shin-Etsu Kagaku Kogyo Co., Ltd. On-site F term (reference) 3C058 AA03 AA09 CA01 CB01 CB03 DB07 DB08 3C063 AA02 AB03 BA24 BB02 BG01 EE01 EE31 3C069 AA03 BA04 BB01 BB02 CA11 EA01 EA04 4G021 BA00

Claims (5)

[Claims] 1. A tool for making a cut for breaking an optical fiber preform rod, comprising: a disk blade having abrasive grains on its surface and having radial grooves formed on the front and back surfaces of an outer peripheral portion; An optical fiber preform rod breaking tool, which is mounted on a driving tool. 2. The optical fiber preform rod breaking tool according to claim 1, wherein the abrasive grains are diamond abrasive grains. 3. A disk blade having abrasive grains on its surface and having radial grooves formed on the front and back surfaces of the outer peripheral portion, while rotating the disk blade on the side surface circumference of the optical fiber preform rod. A method of breaking an optical fiber preform rod in which a cut is made by pressing an outer peripheral portion of a blade, and then an impact is given to the side surface circumference with a hammer. 4. The notch is an arc having a length of at least ８ of the entire circumference of the side surface circumference, and the impact is applied on the side surface circumference near the center of an uncut arc. The method for breaking an optical fiber preform rod according to claim 3, wherein: 5. The method for breaking an optical fiber preform rod according to claim 3, wherein the abrasive grains are diamond abrasive grains.