JP6664426B2 - Optical fiber cutting method and optical fiber cutter - Google Patents

Description

  The present invention relates to an optical fiber cutting method and an optical fiber cutter.

In general, when cutting an optical fiber, the coating of the optical fiber is removed to obtain a bare optical fiber, and then the bare optical fiber is scratched at an initial stage, grown up, and cut by cleavage.
However, in this cutting method, there is a problem that the removal of the coating is troublesome and costly. In addition, since the bare optical fiber is easily damaged, there is also a problem that disconnection easily occurs.
To solve this problem, Patent Literature 1 discloses a method of cutting an optical fiber core wire without removing a coating.
In the method described in Patent Literature 1, after the optical fiber core wire from which the coating has not been removed is wired so as not to slack, a scuffing blade is pressed against the optical fiber core wire to cut a part of the coating and the optical fiber. An initial flaw is formed in the body (bare optical fiber).
Next, the optical fiber core is cut by applying a large tension to the optical fiber to grow an initial scratch.
In this cutting method, since the coating is not removed, the above-mentioned problems of cost increase and disconnection hardly occur.

JP-A-62-194204

However, in the optical fiber cutting method described above, since the initial scratch is formed on the bare optical fiber that is not exposed to the outer surface, it is difficult to determine the depth dimension of the initial scratch with high accuracy.
If the depth dimension of the initial flaw is excessively small, the initial flaw may not grow even if tension is applied to the optical fiber, and the optical fiber may not be cut well. If the depth dimension of the initial flaw is excessively large, the cut surface of the optical fiber is disturbed, and there is a possibility that a problem such as loss occurs when this optical fiber is connected to another optical fiber.

  The present invention has been made in view of the above circumstances, and has as its object to provide an optical fiber cutting method and an optical fiber cutter in which an initial flaw is formed on an optical fiber with a simple and high accuracy and a good cut surface is obtained. And

In order to solve this problem, the present invention is to put a coated optical fiber covering the side surface of the optical fiber body with a coating on the mounting surface of the mounting table, in a state where a tensile force is applied to the coated optical fiber, The coated optical fiber is cut by cleavage by pressing a cutting tool against the coated optical fiber on the placement surface to form an initial flaw in the optical fiber main body, and the tensile force has an initial flaw. Provided is an optical fiber cutting method that has a tensile force enough to cut an optical fiber body by cleavage.
The tensile force is preferably 50 to 800 gf.
It is preferable that the mounting surface of the mounting table has a Young's modulus of at least a portion where the optical fiber is mounted is 1 MPa to 3 MPa.
In pressing the cutting tool against the coated optical fiber, it is preferable that the moving speed of the cutting tool in the pressing direction be 0.6 mm / s or less.
The angle of the cross section of the tip of the blade is preferably 45 to 90 °.
It is preferable that the pressing force when pressing the cutting tool against the optical fiber body is 1 to 8N.

  The present invention provides a mounting table having a mounting surface for mounting a coated optical fiber in which a side surface of an optical fiber body is covered with a coating, a tension applying mechanism for applying a tensile force to the coated optical fiber, By being pressed against the coated optical fiber placed on the surface, the side surface of the optical fiber main body forms an initial flaw for promoting the cutting of the optical fiber main body, and the initial flaw is formed by the tension applying mechanism. A moving mechanism for moving the cutting tool toward the coated optical fiber on the placement surface, wherein the moving mechanism is provided with a tensile force enough to cut the optical fiber body by cleavage. I do.

It is preferable that the placement surface is a receiving protrusion protruding in a direction approaching the blade, and an outer surface with which the optical fiber abuts is a curved surface.
The static friction coefficient of the placing surface is preferably 2 or less.
It is preferable that the mounting table is movable in a direction approaching and separating from the cutting tool, and is urged toward the cutting tool by urging means.
The optical fiber cutter of the present invention further includes a base holding the cutting tool, wherein the cutting tool is movable in a direction approaching the mounting surface by pressing by a pressing body attached to the base, and However, it is preferable that the screw tool is a screw-type pressing tool that can press the blade tool by performing a screw feeding operation by a rotation operation.

ADVANTAGE OF THE INVENTION According to the optical fiber cutting method and the optical fiber cutter according to the present invention, an initial scratch is formed on the optical fiber main body by pressing the cutting tool in a state where a sufficient tensile force is applied to the coated optical fiber placed on the mounting table.
When the initial flaw is formed to an appropriate depth, the initial flaw grows by the tensile force, and the optical fiber is cut by cleavage. Therefore, the depth of the initial scratch does not become insufficient or excessive, and the cutting of the optical fiber main body proceeds smoothly.
Therefore, an initial flaw is formed in the optical fiber with ease and high accuracy, and a good cut surface can be obtained.

FIG. 1 is a schematic diagram illustrating an optical fiber cutter according to a first embodiment of the present invention. FIG. 2 is an explanatory diagram illustrating an operation of the optical fiber cutter of FIG. 1. FIG. 2 is an explanatory diagram illustrating an operation of the optical fiber cutter of FIG. 1. It is a schematic diagram which shows the relationship between a cutting tool and an optical fiber, (a) shows the stage which formed the initial flaw, and (b) shows the stage where the cutting of the optical fiber was completed. It is a schematic diagram which shows the structure of an optical fiber. It is a perspective view showing the optical fiber cutter concerning a 2nd embodiment of the present invention. FIG. 7 is an exploded perspective view showing the optical fiber connector of FIG. 6. FIG. 7 is a cross-sectional view of the optical fiber connector of FIG. 6 along the XY plane. It is an enlarged view which shows a cutting tool and a mounting table. FIG. 7 is a cross-sectional view of the optical fiber connector of FIG. 6 along the YZ plane. It is explanatory drawing which shows the effect | action of a tension provision mechanism. FIG. 7 is an explanatory diagram illustrating an operation of the optical fiber cutter of FIG. 6. FIG. 7 is an explanatory diagram illustrating an operation of the optical fiber cutter of FIG. 6. FIG. 7 is an explanatory diagram illustrating an operation of the optical fiber cutter of FIG. 6. FIG. 7 is an explanatory diagram illustrating an operation of the optical fiber cutter of FIG. 6.

(1st Embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 5 shows an example of an optical fiber to be cut. The optical fiber 9 shown here has a coating in which the outer peripheral surface (side surface) of an optical fiber main body 9a (bare optical fiber) is covered with a coating 9b. For example, a single-core optical fiber core wire, an optical fiber strand, or the like can be used.
The optical fiber body 9a (bare optical fiber) is, for example, a silica-based optical fiber. The coating 9b is a resin coating of one or more layers made of, for example, an ultraviolet curable resin (urethane acrylate resin or the like), a polyamide resin, or the like.

As shown in FIG. 1, the optical fiber cutter 1 includes a mounting table 2 having a mounting surface 2 a on which an optical fiber 9 is mounted, a tension applying mechanism 3 for applying a tensile force to the optical fiber 9, and an optical fiber 9. A cutting tool unit 4 (cutting tool unit) for forming an initial flaw and a moving mechanism 5 for moving the cutting tool unit 4 in a direction to approach and separate from the mounting table 2 are provided.
Hereinafter, “up” and “down” are defined based on the vertical direction in FIG.

The mounting table 2 is, for example, a substantially rectangular parallelepiped block, and the upper surface thereof is a mounting surface 2a on which the optical fiber 9 is mounted. The mounting surface 2a can be a curved surface that is convex upward. The mounting surface 2a may be, for example, a curved surface having a substantially circular or elliptical arc cross section.
By setting the mounting surface 2a as a curved convex surface, the optical fiber 9 can be supported at the top of the mounting surface 2a, and when the optical fiber 9 is cut by the blade unit 4, the pressing force of the blade 16 is reduced. The fiber 9 can be reliably acted on.

At least a portion of the mounting table 2 where the optical fiber 9 is mounted is made of, for example, plastic or the like, and preferably has a Young's modulus of 1 MPa to 3 MPa.
By setting the Young's modulus of the mounting table 2 to 1 MPa or more, even if the pressing force of the cutting tool 16 varies, the mounting table 2 is slightly deformed to absorb the unevenness of the pressing force, so that the appropriate depth can be obtained. Initial scratches can be formed. Further, by setting the Young's modulus to 1 MPa or more, it is possible to stably form a cut surface perpendicular (or substantially perpendicular) to the optical axis direction.
By setting the Young's modulus of the mounting table 2 to 3 MPa or less, excessive elastic deformation of the mounting table 2 with respect to the pressing force of the cutting tool 16 is suppressed, and the pressing load of the cutting tool 16 is applied to the optical fiber 9 without fail. Initial scratches of depth can be formed.
For this reason, by setting the Young's modulus of the mounting table 2 to 1 MPa to 3 MPa, it is possible to set the pressing load of the blade tool 16 in an appropriate range, form an initial scratch having an appropriate depth, and obtain a good cut surface. it can.
The mounting surface 2a is not limited to a curved surface, but may be a flat surface.

  The tension applying mechanism 3 includes a fixing portion 10 for fixing the first fixing portion 9A of the optical fiber 9, an optical fiber holder 11 for holding the second fixing portion 9B of the optical fiber 9, and the optical fiber holder 11 from the fixing portion 10. And a spring 12 (biasing means) for biasing in a separating direction.

  As the fixing portion 10, for example, a structure in which the first fixing portion 9A is sandwiched and fixed between the base portion and the lid can be adopted.

The optical fiber holder 11 includes a base portion 21 and a lid 22 provided rotatably with respect to the base portion 21. The lid 22 can hold the second fixing portion 9 </ b> B of the optical fiber 9 between the lid 22 and the base 21.
The second fixing point 9B is a point separated from the first fixing point 9A in the longitudinal direction of the optical fiber 9.
The optical fiber holder 11 is movable in a direction approaching and separating from the fixing unit 10. As a structure that enables the optical fiber holder 11 to move in the above-mentioned direction, for example, an installation table (not shown) having a groove-shaped rail portion along the above-mentioned direction may be used. The rail section can be formed so that the optical fiber holder 11 can slide.

A positioning groove (not shown) for positioning the optical fiber 9 may be formed in the base portion 21 or the lid 22 so that the longitudinal direction of the optical fiber 9 matches the moving direction of the optical fiber holder 11.
The position of the optical fiber holder 11 is determined so that the optical fiber 9 is mounted on the mounting table 2 at an intermediate position between the first fixing point 9A and the second fixing point 9B.

The spring 12 is an elastic member such as a coil spring and a leaf spring. The spring 12 applies a reaction force to the wall member 13 to urge the optical fiber holder 11 in a direction away from the fixing portion 10 (to the right in FIG. 1).
Reference numeral 14 in FIG. 1 denotes a spring that applies a reaction force to the wall member 15 and urges the optical fiber holder 11 in a direction approaching the fixing portion 10.

The blade unit 4 includes a blade 16, a base 17 installed at a distance from the blade 16, and a spring 18 that urges the blade 16 toward the optical fiber 9 by reacting with the base 17 (downward in FIG. 1). (Biasing means).
The blade tool 16 forms an initial flaw on the side surface of the optical fiber 9 by being pressed against the optical fiber 9 mounted on the mounting surface 2 a of the mounting table 2. The cross section can be formed to have an acute angle. The cutting tool 16 can be, for example, wedge-shaped.

The cutting tool 16 is made of, for example, a cemented carbide. The angle α of the cross section of the tip 16a of the blade 16 is preferably 45 to 90 ° (preferably 45 ° or more and less than 90 °).
By setting the angle α in this range, the blade 16 can be provided with high durability, and an initial scratch having a sufficient depth can be formed in the optical fiber main body 9a (bare optical fiber) of the optical fiber 9.
The cutting tool 16 may have, for example, a structure including a wedge-shaped cutting tool body formed in an acute angle cross section whose thickness decreases toward the tip, and a polishing sheet (not shown) attached to the tip. The polishing sheet has abrasive grains such as diamond abrasive grains / alumina-based abrasive grains having a hardness equal to or higher than that of quartz-based glass.

  The moving mechanism 5 moves the blade unit 4 in a direction to approach and separate from the mounting surface 2 a of the mounting table 2, and is connected to the base 17 of the blade unit 4 via a connecting arm 23.

As the moving mechanism 5, it is preferable to adopt a structure in which the blade unit 4 is moved up and down by a motor (not shown) because the moving speed can be accurately determined.
The moving mechanism 5 includes, for example, a motor (not shown), a cam (not shown) driven by the motor to move the base 17 up and down via the connecting arm 23, and a control unit (not shown) for controlling the number of rotations of the motor. ).
The moving mechanism 5 can move the blade unit 4 up and down at an arbitrary speed by controlling the number of rotations of the motor by the control unit. The moving mechanism 5 can move the blade unit 4 up and down at a constant speed by making the rotation speed of the motor constant by the control unit.
The drive mechanism used for the moving mechanism 5 is not limited to a motor, and may be another drive mechanism (such as a spring). Further, a structure in which the operator manually moves the blade unit 4 up and down may be adopted.

Next, an optical fiber cutting method for cutting the optical fiber 9 using the optical fiber cutter 1 will be described.
(Tension applying step)
As shown in FIG. 1, the first fixing portion 9A of the optical fiber 9 is fixed to the fixing portion 10, and the second fixing portion 9B is sandwiched and held between the base portion 21 and the lid 22 of the optical fiber holder 11. I do. At this stage, the movement of the optical fiber holder 11 in the direction away from the fixing unit 10 may be restricted.
The optical fiber 9 is mounted on the mounting surface 2a of the mounting table 2 at an intermediate position between the first fixing point 9A and the second fixing point 9B.

Next, as shown in FIG. 2, the optical fiber holder 11 is brought into a movable state. Accordingly, the optical fiber holder 11 moves in a direction (rightward in FIG. 2) away from the fixing unit 10 by the pressing force of the spring 12, and a tensile force is applied to the optical fiber 9.
It is desirable that the stopper 24 restricts the movement of the optical fiber holder 11 in the direction of the fixing portion 10 at a position where a tensile force is applied to the optical fiber 9. Thereby, a tensile force can be stably applied to the optical fiber 9.

The tensile force applied to the optical fiber 9 is a force that, when the optical fiber main body 9a (bare optical fiber) has an initial flaw, grows the initial flaw and cuts the optical fiber main body 9a by cleavage.
This tensile force is preferably from 50 to 800 gf (0.49 to 7.84 N). The tensile force is preferably more than 50 gf and 800 gf or less, more preferably 150 to 300 gf (1.47 to 2.94 N). Note that 1000 gf corresponds to 9.8 N.
If the tensile force is too small, the cutting of the optical fiber 9 may be hindered, and if it is too large, the cut surface may not be good. However, by setting the above range, the optical fiber 9 is reliably cut, and A good cut surface can be obtained.
This tensile force may vary in the above range, but is preferably constant in this step and the next step.
At this stage, the cutting tool 16 is not in contact with the optical fiber 9.

(Initial scratch formation step)
Next, as shown in FIG. 3, the cutting tool unit 4 is lowered by the moving mechanism 5, and the tip of the cutting tool 16 is pressed against the side surface of the coating 9b of the optical fiber 9 on the mounting surface 2a. Thus, the optical fiber 9 is in a state of being sandwiched between the mounting surface 2a and the tip of the blade 16.
When the blade 16 is further lowered, the tip 16a of the blade 16 is cut into the coating 9b and reaches the optical fiber main body 9a (bare optical fiber).
As shown in FIG. 4A, when the blade 16 is further lowered, an initial scratch 9c is formed on the side of the optical fiber body 9a (bare optical fiber) by the blade 16.

The lowering speed of the blade unit 4 is preferably 0.6 mm / s or less. If the descending speed is too fast, the initial scratches become too deep and it is difficult to obtain a good cut surface. However, by setting the descending speed in the above range, the optical fiber main body 9a (bare optical fiber) has an appropriate depth. An initial flaw can be formed and a good cut surface can be obtained.
The lowering speed of the blade unit 4 is preferably 0.3 mm / s or more, since the working efficiency is reduced if it is too slow.

  When the blade 16 is pressed against the optical fiber body 9a (bare optical fiber), the spring 18 is compressed by the base 17 descended by the moving mechanism 5, so that the elastic force of the spring 18 also acts on the blade 16.

The pressing force when the blade 16 is pressed against the optical fiber body 9a (bare optical fiber) is preferably 1N or more.
By setting the pressing force within this range, an initial scratch having an appropriate depth is formed in the optical fiber main body 9a (bare optical fiber), and a good cut surface can be obtained.
If the pressing force is too large, the cutting tool 16 is likely to be damaged.

(Cutting process)
As shown in FIG. 4B, as described above, since the tensile force is applied to the optical fiber 9 by the tension applying mechanism 3, the depth of the initial flaw formed in the optical fiber main body 9a (bare optical fiber) is increased. At the stage when the size reaches a predetermined size (for example, 5 μm to 20 μm), an initial scratch grows by a tensile force, and the optical fiber main body 9 a (bare optical fiber) is cut by cleavage.
When the optical fiber main body 9a (bare optical fiber) is cut, the tensile force acts on the uncut portion of the coating 9b, and the coating 9b is also cut.
Reference numeral 9d denotes a cut surface of the cut optical fiber 9. The cut surface 9d is preferably perpendicular to the axial direction of the optical fiber main body 9a.

According to the optical fiber cutting method of the present embodiment, an initial scratch is formed on the optical fiber main body 9a by pressing the cutting tool 16 in a state where a sufficient tensile force is applied to the optical fiber 9 placed on the mounting table 2.
At the stage where the initial flaw is formed at an appropriate depth, the initial flaw grows by the tensile force, and the optical fiber 9 is cut by cleavage. Therefore, the depth of the initial scratch does not become insufficient or excessive, and the cutting of the optical fiber main body 9a proceeds smoothly.
Therefore, an initial flaw is formed in the optical fiber 9 simply and with high accuracy, and a good cut surface can be obtained.

(2nd Embodiment)
Next, an optical connector 20 according to a second embodiment of the present invention will be described with reference to FIGS.
Hereinafter, the structure will be described with reference to the XYZ orthogonal coordinate system shown in FIG. The X direction is the front-back direction, which is the direction in which the first optical fiber holder 32 and the second optical fiber holder 33 are arranged. The X direction is also the length direction of the optical fiber 9. The Y direction is a direction (width direction) orthogonal to the X direction in a plane parallel to the bottom surface of the mounting recess 45a of the base 28. The Z direction is a height direction orthogonal to the X direction and the Y direction. The same components as those in the above-described first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIGS. 6 to 8, the optical fiber cutter 20 includes a mounting table 25 for mounting the optical fiber 9, a tension applying mechanism 26 for applying a tensile force to the optical fiber 9, and an initial scratch on the optical fiber 9. A cutting tool unit 27 to be formed, a base 28, and a moving mechanism 29 for moving the cutting tool unit 27 toward and away from the mounting table 25 are provided.

As shown in FIG. 8, the mounting table 25 has a base body 25a formed in a substantially cylindrical shape (covered cylindrical shape) having a top wall portion 25a1, and a receiver formed on an outer surface thereof (an outer surface of the top wall portion 25a1). A projection 25b.
As shown in FIG. 9, the receiving projection 25 b is formed at a position facing the cutting tool 16 so as to protrude from the outer surface of the top wall 25 a 1 in the Y direction (direction approaching the cutting tool unit 27).
The receiving projection 25b extends in the height direction (Z direction; a direction perpendicular to the paper surface), and the outer surface 25b2 of the top 25b1 is a curved surface that protrudes outward. The cross-sectional shape of the top 25b1 can be, for example, an arc shape, an elliptical arc shape, or the like.

The outer surface 25b2 of the top 25b1 is a mounting surface (contact surface) on which the optical fiber 9 is mounted.
Here, the term “mounting” is not limited to the case where the optical fiber 9 is placed on the optical fiber 9, but refers to the case where the optical fiber 9 comes into contact when the blade 16 is pressed.

Since the outer surface 25b2 of the top 25b1 is a curved surface, the optical fiber 9 comes into contact with a small area.
For this reason, the frictional force in a state where the optical fiber 9 is pressed against the receiving projection 25b by the cutting tool 16 can be reduced, and the optical fiber 9 can be easily moved in the longitudinal direction. Therefore, a sufficient tensile force can be given to the optical fiber 9.

The radius of curvature of the cross section (XY cross section) of the outer surface 25b2 of the top 25b1 can be, for example, 5 mm or less.
If the radius of curvature is too small, when the position of the blade 16 with respect to the mounting table 25 is shifted in the X direction, the direction and magnitude of the pressing force of the blade 16 acting on the optical fiber 9 may be largely changed. If the radius of curvature is too large, the frictional force in a state where the optical fiber 9 is pressed against the receiving projection 25b by the cutting tool 16 increases.
On the other hand, by setting the radius of curvature in this range, even if the position of the blade 16 with respect to the mounting table 25 is shifted in the X direction, the direction and magnitude of the pressing force acting on the optical fiber 9 do not greatly change. Therefore, a good cut surface can be obtained.
In addition, since the frictional force in a state where the optical fiber 9 is pressed against the receiving projection 25b by the blade tool 16 can be reduced, a sufficient tensile force can be applied to the optical fiber 9.
In addition, since the outer surface 25b2 of the top 25b1 is not a sharp shape but a curved surface, even if the position of the blade 16 with respect to the mounting table 25 is shifted in the X direction, the direction and magnitude of the pressing force acting on the optical fiber 9 are increased. Does not fluctuate significantly.

The coefficient of static friction (for example, based on JIS K7125) of the outer surface 25b2 of the top 25b1 can be set to, for example, 2 or less.
Thereby, even when the optical fiber 9 is pressed against the receiving projection 25b by the blade tool 16, the optical fiber 9 can be easily moved in the longitudinal direction, so that a sufficient tensile force can be applied to the optical fiber 9. .

The receiving projection 25b is made of, for example, plastic or the like, and preferably has a Young's modulus of 1 MPa to 3 MPa.
By setting the Young's modulus to 1 MPa or more, even if the pressing force of the cutting tool 16 varies, an initial scratch having an appropriate depth can be formed. Further, by setting the Young's modulus to 3 MPa or less, excessive elastic deformation of the receiving projection 25b with respect to the pressing force of the cutting tool 16 is suppressed, and the pressing load of the cutting tool 16 is applied to the optical fiber 9 with sufficient depth. Initial scratches can be formed.

As shown in FIG. 10, an accommodation recess 25 c is formed in the mounting table 25, and a first spring 30 (mounting table urging means) is provided therein.
The first spring 30 is an elastic member such as a coil spring and a leaf spring. The first spring 30 can urge the mounting table 25 in a direction approaching the blade 16 by applying a reaction force to the mounting table support portion 31 attached to the base 28.

The mounting table 25 is movable in a direction approaching and separating from the blade tool 16. For this reason, by appropriately setting the elastic force of the first spring 30, it is possible to prevent the pressing force of the cutting tool 16 against the optical fiber 9 from becoming excessive.
For example, even when the moving speed of the cutting tool 16 in the forward direction is too high, the pressing force applied to the optical fiber 9 can be reduced, and the cut surface of the optical fiber 9 can be improved.

  As shown in FIG. 7, the tension applying mechanism 26 holds a first optical fiber holder 32 (fixing portion) that holds and fixes the first fixing portion 9A of the optical fiber 9 and a second fixing portion 9B of the optical fiber 9. A second optical fiber holder 33 for fixing and fixing, a second spring 40 (biasing means), and a tension adjusting mechanism 39 are provided.

The first optical fiber holder 32 includes a first base 35 and a first lid 36 hinged to the first base 35.
The first base portion 35 has a base portion main body 35d, and wall portions 35a provided at a front end and a rear end of the base portion main body 35d. A first positioning groove 35b for positioning the optical fiber 9 is formed in the wall 35a.
The first lid 36 can hold the first fixing portion 9A of the optical fiber 9 between the first lid 36 and the first base 35.

The second optical fiber holder 33 includes a second base 37 and a second lid 38 hinged to the second base 37. The second base portion 37 has a base portion main body 37d, a wall portion 37a provided at a front end of the base portion main body 37d, and a pair of arm portions 37c extending forward from the wall portion 37a. A second positioning groove 37b for positioning the optical fiber 9 is formed in the wall 37a.
The second lid 38 can hold the second fixing portion 9B of the optical fiber 9 between the second base 38 and the second base 37.

As shown in FIG. 8, the second spring 40 is made of an elastic member such as a coil spring and a leaf spring.
The second spring 40 urges the first optical fiber holder 32 in a direction away from the second optical fiber holder 33 by applying a reaction force to the base 43.

The tension adjusting mechanism 39 includes a substantially disc-shaped cam portion 42 and a handle 41 extending outward from the cam portion 42.
The cam portion 42 is rotatably attached to the frame portion 46 of the base 28 at the eccentric position via a rotation shaft 42a.

FIG. 11 is an explanatory diagram showing the operation of the tension adjusting mechanism 39.
As shown in FIG. 11A, when the handle 41 is turned in the Y direction, the outer surface of the cam portion 42 presses the first optical fiber holder 32 toward the base portion 43, and abuts (or approaches) the base portion 43. Let it. In this state, there is a gap between the inner surface 46a1 of the opening 46a of the frame 46 and the outer surface 35c of the first base 35 of the first optical fiber holder 32.

  As shown in FIG. 11B, when the handle 41 is turned in the X direction, the cam portion 42 is turned around the turning shaft 42a to release the pressing on the first optical fiber holder 32. Can be. In a state where the optical fiber 9 is not present, the first optical fiber holder 32 is moved by a distance L in a direction away from the second optical fiber holder 33 (leftward in FIG. 11) by the urging force of the second spring 40 (see FIG. 8). It moves and contacts the inner surface 46a1 of the frame portion 46.

As shown in FIGS. 7 and 8, the blade unit 27 includes the blade 16 and a blade support portion 44 that supports the blade 16.
The cutting tool 16 is preferably made of ceramic or metal coated with titanium. As the cutting tool 16, an NT blade may be employed.
The cutting tool 16 is provided such that a tip portion protrudes from the cutting tool support portion 44.

The base 28 has a block-shaped base 43, a holder mounting table 45 provided on one side of the base 43 for mounting the second optical fiber holder 33, and a first base provided on the other side of the base 43. And a frame 46 for holding the optical fiber holder 32.
The base 43 includes a cutting tool housing 47 for housing the cutting tool unit 27 and a mounting table housing 48 for housing the mounting table 25.

A mounting recess 45 a for holding the second optical fiber holder 33 is formed in the holder installation table 45. The mounting recess 45a is formed in a groove shape along the X direction.
A regulating wall portion 45b that regulates the movement of the second optical fiber holder 33 in the direction approaching the first optical fiber holder 32 is formed on the holder installation base 45. A passage recess 45c through which the optical fiber 9 passes is formed in the regulating wall 45b.

The dimension of the opening 46a of the frame 46 in the X direction is larger than the dimension of the first optical fiber holder 32 in the X direction. For this reason, the frame part 46 can hold the first optical fiber holder 32 in a state where the first optical fiber holder 32 can move in the direction (X direction) approaching and separating from the second optical fiber holder 33.
The frame portion 46 is preferably formed such that the height of the first positioning groove 35b of the first optical fiber holder 32 matches the height of the second positioning groove 37b of the second optical fiber holder 33.

As shown in FIG. 8, a hole 47 a into which the blade support 44 is inserted is formed in the blade housing 47.
A hole 48 a (see FIG. 10) for receiving the mounting table 25 and the first spring 30 is formed in the mounting table housing 48.

As shown in FIG. 10, the moving mechanism 29 includes a pressing body 52 and a support 51 that supports the pressing body 52.
The pressing body 52 includes a screw shaft 49 and a head 50 provided at one end thereof. The screw shaft portion 49 is formed with a male screw 49a that is screwed into a female screw surface 51b formed in the insertion hole 51a of the support portion 51.
The support portion 51 is fixed to the blade housing portion 47.
The pressing body 52 is a screw-type pressing tool that is capable of pressing the blade tool support part 44 by screw-feeding the screw shaft part 49 by a rotation operation around the axis.
By using the pressing body 52 adopting the screw-type pressing mechanism, the operation for moving the blade support portion 44 is simplified, and the moving speed of the blade 16 is easily adjusted.
The moving mechanism 29 has a structure in which the pressing body 52 indirectly presses the blade 16 via the blade supporting portion 44, but the pressing body 52 may have a structure in which the pressing body 52 directly presses the blade 16.

Next, a method of cutting the optical fiber 9 using the optical fiber cutter 20 will be described.
(Tension applying step)
As shown in FIG. 12, the handle 41 of the tension adjusting mechanism 39 is oriented in the Y direction, and the first optical fiber holder 32 is pressed by the cam portion 42 toward the base portion 43, and is brought into contact with (or close to) the base portion 43. State.
The first fixing portion 9A of the optical fiber 9 is sandwiched and held between the first base portion 35 of the first optical fiber holder 32 and the first lid 36 (see FIG. 7), and the second fixing portion 9B is held. The second optical fiber holder 33 is sandwiched and held between the second base 37 and the second lid 38.
The optical fiber 9 makes the portion between the first fixing portion 9A and the second fixing portion 9B contact (or approach) the outer surface 25b2 of the top portion 25b1 of the receiving convex portion 25b of the mounting table 25.

  Next, as shown in FIG. 13, by turning the handle 41 in the X direction, the cam portion 42 is rotated about the rotation shaft 42 a to release the pressing on the first optical fiber holder 32. Since the optical fiber 9 is fixed to the first optical fiber holder 32, a tensile force is applied to the optical fiber 9.

The tensile force applied to the optical fiber 9 is preferably 50 to 800 gf (0.49 to 7.84 N), as in the first embodiment. The tensile force is preferably more than 50 gf and 800 gf or less, more preferably 200 to 500 gf. Among them, 200 to 400 gf is particularly preferable, and 200 to 250 gf is more preferable.
If the tensile force is too small, it is difficult to obtain a good cut surface because the initial scratch becomes too deep. If the tensile force is too large, the fracture (crack formation) proceeds faster than the growth of the initial scratch, so that good cutting is performed. Although it is difficult to obtain a surface, a good cut surface can be obtained by setting the tensile force within the above range.

Since the optical fiber 9 is a coated optical fiber, in order to obtain a good cut surface when the moving speed (forward speed) of the cutting tool 16 is high, a larger pulling force is required as compared with an uncoated optical fiber. May be.
This is because if the moving speed (forward speed) of the cutting tool 16 is high, the cutting of the coating 9b may be delayed by a small tensile force.
On the other hand, when the moving speed (forward speed) of the cutting tool 16 is low, there is almost no difference in the pulling force required to obtain a good cut surface as compared with an uncoated optical fiber.
This is because if the moving speed (advance speed) of the cutting tool 16 is low, even if the pulling force is small, it can sufficiently act on the coating 9b, so that the cutting delay of the coating 9b hardly occurs.

(Initial scratch formation step)
Next, as shown in FIG. 14, the pressing body 52 is advanced by grasping and rotating the head 50 of the moving mechanism 29 around the axis, and the tip end of the screw shaft 49 presses the blade support 44. As a result, the blade 16 is advanced toward the mounting table 25, and the tip of the blade 16 is pressed against the side surface of the optical fiber 9 in contact with the receiving projection 25b.
The tip 16a of the blade 16 is cut into the coating 9b, reaches the optical fiber body 9a (bare optical fiber), and forms an initial scratch 9c on the side surface of the optical fiber body 9a.

  In the optical fiber cutting method of the present embodiment, if the moving speed (advancing speed) of the cutting tool 16 is kept within a predetermined range, many of the coating 9b are cut before the optical fiber main body 9a (bare optical fiber) is cut. Parts can be cut. For example, the coating 9b can be cut not only in a part of the coating 9b in the circumferential direction but also in a wide range in the circumferential direction (preferably over the entire circumference).

By controlling the moving speed, it is possible to cut a large part of the coating 9b because the initial flaw formed on the optical fiber main body 9a (bare optical fiber) is applied to the optical fiber 9 before the initial flaw is deepened. This is because the applied tensile force can sufficiently act on the coating 9b.
On the other hand, if the moving speed of the cutting tool 16 is too high, the cutting tool 16 reaches the optical fiber main body 9a in a short time and forms a deep initial flaw. The main body 9a is easily cut.

Specifically, the moving speed of the blade 16 is preferably equal to or less than 0.6 mm / s as in the first embodiment.
Thereby, before the optical fiber main body 9a (bare optical fiber) is cut, the coating 9b can be cut over a wide range in the circumferential direction (preferably over the entire circumference).
The lowering speed of the blade unit 4 is preferably 0.3 mm / s or more, since the working efficiency is reduced if it is too slow.

The pressing force when the blade 16 is pressed against the optical fiber body 9a (bare optical fiber) is preferably 1N or more, as in the first embodiment.
By setting the pressing force within this range, an initial scratch having an appropriate depth is formed in the optical fiber main body 9a (bare optical fiber), and a good cut surface can be obtained.
If the pressing force is too large, the cutting tool 16 is likely to be damaged.

(Cutting process)
As shown in FIG. 15, since the tensile force is applied to the optical fiber 9 by the tension applying mechanism 26, the depth dimension of the initial flaw formed on the optical fiber body 9a (bare optical fiber) is a predetermined size. At the stage of (for example, 5 μm to 20 μm), the initial scratch grows by the tensile force, and the optical fiber main body 9 a (bare optical fiber) is cut by the cleavage.
As the optical fiber 9 is cut, the first optical fiber holder 32 moves in a direction (arrow direction) away from the base 43 by the urging force of the second spring 40.
The first optical fiber holder 32 moves until the outer surface 35c contacts the inner surface 46a1 of the frame portion 46.

According to the optical fiber cutting method of the present embodiment, a sufficient tensile force can be applied to the optical fiber 9 by the tension applying mechanism 26. In this state, the blade 16 is pressed against the side surface of the optical fiber 9 by the moving mechanism 29, thereby forming an initial scratch on the optical fiber main body 9a.
At the stage where the initial flaw is formed at an appropriate depth, the initial flaw grows by the tensile force, and the optical fiber 9 is cut by cleavage. Therefore, the depth of the initial scratch does not become insufficient or excessive, and the cutting of the optical fiber main body 9a proceeds smoothly.
Therefore, an initial flaw is formed in the optical fiber 9 simply and with high accuracy, and a good cut surface can be obtained.

In the optical fiber cutting method according to the present embodiment, the cutting speed of the cutting tool 16 is suppressed to a predetermined range because the cutting tool 16 cuts the optical fiber 9 while a sufficient tensile force is applied to the optical fiber 9. If this is the case, many portions of the coating 9b can be cut before the optical fiber body 9a (bare optical fiber) is cut.
For example, before the optical fiber body 9a (bare optical fiber) is cut, it is possible to cut the coating 9b not only in a part of the coating 9b in the circumferential direction but also in a wide range in the circumferential direction (preferably over the entire circumference). it can.
For this reason, whether the target optical fiber is a coated optical fiber or an optical fiber from which the coating has been removed, an initial scratch can be formed on the optical fiber main body 9a under the same conditions.
Therefore, this optical fiber cutting method can be commonly used for both coated optical fibers and optical fibers from which the coating has been removed.

In addition, the present invention provides the above-described tensile force by pressing a cutting tool against the coated optical fiber and forming an initial scratch on the optical fiber body in a state where a tensile force is applied to the coated optical fiber placed on the mounting surface. The optical fiber may be cleaved and cut.
The optical fiber cutting method of the present invention can be applied to the case where the coating 9b of the coated optical fiber 9 is removed and the optical fiber in a state where the optical fiber main body 9a is exposed is cut.
The blade tool unit 27 shown in FIG. 8 and the like includes the blade tool support portion 44, the blade tool 16 supported by the blade tool support portion 44, and a spring (biasing means) for biasing the blade tool 16 in a direction approaching the mounting table 25. May be adopted.

Reference numerals 1, 20: optical fiber cutter, 2, 25: mounting table, 2a, 25b1: mounting surface, 3: fixed portion, 4, 26: tension applying mechanism, 5, 27: blade unit (blade portion), 6, 29 ... moving mechanism, 9 ... optical fiber (coated optical fiber), 9a ... optical fiber body (bare optical fiber), 9b ... coating, 9c ... initial scratch, 11 ... optical fiber holder, 12 ... spring, 16 ... blade, 25b .., Receiving projection, 30 first spring (biasing means), 32 first optical fiber holder (fixed part), 33 second optical fiber holder.

Claims (12)

The coated optical fiber in which the side surface of the optical fiber body is covered with the coating is applied with a tensile force such that the optical fiber body having formed the initial scratch is cleaved and cut,
Prepare a non-rotating blade with a wedge-shaped cross section whose tip crosses the longitudinal direction of the optical fiber,
Place the mounting table having a convex cross section having a curved convex mounting surface for receiving the cutting tool in such a manner that the mounting surface corresponds to the direction of the tip of the cutting tool and can be cut into the coating of the coated optical fiber. So that
By applying the tensile force and pressing the cutting tool to the coated optical fiber in the state of being in close proximity to the mounting table, the pressed portion of the coated optical fiber is moved toward the mounting table, and contact is touching the surface, the cutting tool to form an initial flaw to the optical fiber body on which cut into the coating, said coated optical fiber by the tensile force before the initial flaw is formed unnecessarily cleavage Optical fiber cutting method.   The optical fiber cutting method according to claim 1, wherein the tensile force is 50 to 800 gf.   The optical fiber cutting method according to claim 1, wherein the mounting surface of the mounting table has a Young's modulus of at least a portion where the optical fiber is mounted is 1 MPa to 3 MPa.   The optical fiber cutting method according to any one of claims 1 to 3, wherein a pressing speed of the blade in a pressing direction is 0.6 mm / s or less when the blade is pressed against the coated optical fiber.   The optical fiber cutting method according to any one of claims 1 to 4, wherein the angle of the cross section of the tip of the blade is 45 to 90 °. A blade unit comprising: the blade, a base disposed apart from the blade, and blade biasing means for biasing the blade in a direction approaching the coated optical fiber by applying a reaction force to the base. And
The blade tool urging means, when the blade tool is pressed against the coated optical fiber, to apply an elastic force to the blade tool,
The optical fiber cutting method according to any one of claims 1 to 5, wherein when cutting the blade into the coated optical fiber, the base is moved at a constant speed in a direction approaching the coated optical fiber. A mounting table having a convex cross section having a curved convex mounting surface for mounting the coated optical fiber in which the side surface of the optical fiber body is covered with the coating,
A tension applying mechanism that applies a tensile force to the coated optical fiber to such an extent that the optical fiber main body having an initial scratch is cleaved and cut,
By being pressed against the coated optical fiber placed on the placement surface, a side surface of the optical fiber body, a blade tool unit having a blade tool that forms an initial scratch that promotes cutting of the optical fiber body,
A moving mechanism configured to move the blade toward the coated optical fiber on the placement surface, wherein the tension applying mechanism applies a tensile force to the optical fiber main body having the initial flaw so that the optical fiber main body having the initial scratch can be cut by cleavage. And having
The blade is non-rotating, and has a wedge-shaped cross section whose tip intersects the longitudinal direction of the optical fiber,
The mounting table is an optical fiber cutter arranged so that the mounting surface corresponds to the direction of the tip of the cutting tool and is close enough to cut into the coating of the coated optical fiber.   The optical fiber cutter according to claim 7, wherein the placement surface is an outer surface of a receiving protrusion protruding in a direction approaching the blade, and an outer surface with which the optical fiber abuts is a curved surface.   9. The optical fiber cutter according to claim 7, wherein a static friction coefficient of the placing surface is 2 or less.   The optical fiber according to any one of claims 7 to 9, wherein the mounting table is movable in a direction approaching and separating from the blade, and is urged toward the blade by an urging means. Cutter. Further comprising a base holding the cutting tool,
The blade is movable in a direction approaching the mounting surface by pressing by a pressing body attached to the base,
The optical fiber cutter according to any one of claims 7 to 10, wherein the pressing body is a screw-type pressing tool capable of pressing the blade tool by a screw feeding operation of a screw shaft portion by a rotation operation. . The blade unit further includes a base disposed apart from the blade, and a blade urging means for urging the blade in a direction approaching the coated optical fiber by applying a reaction force to the base,
The blade tool urging means, when the blade tool is pressed against the coated optical fiber, to apply an elastic force to the blade tool,
The moving mechanism according to any one of claims 7 to 11, wherein the blade moves toward the coated optical fiber by moving the base toward the coated optical fiber at a constant speed. An optical fiber cutter as described.

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