JP2014238574A - Optical fiber cutting method and optical fiber cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber cutting method and optical fiber cutter that can form an initial flaw in an optical fiber easily and accurately and produce a satisfactory cut surface.SOLUTION: An optical fiber 9 having a coating obtained by covering a side face of an optical fiber body with the coating is placed on a placing surface 2a of a placing stand 2. In the state in which a tensile force is applied to the optical fiber 9 having the coating, a cutting tool 16 is pressed onto the optical fiber 9 having the coating on the placing surface 2a, thereby forming an initial flaw in the optical fiber body. Thus, the optical fiber 9 is cut by cleavage. The tensile force is a tensile force of the extent to which the optical fiber body having the initial flaw can be cut by cleavage.

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 form a bare optical fiber, and then the bare optical fiber is initially scratched and grown, and the optical fiber is cut by cleavage.
However, this cutting method has a problem that it takes time to remove the coating and increases the cost. In addition, since bare optical fibers are easily damaged, disconnection is likely to occur.
To solve this problem, Patent Document 1 describes a method of cutting an optical fiber core wire without removing the coating.
In the method described in Patent Document 1, after the optical fiber core wire from which the coating has not been removed is wired so as not to sag, a scratching blade is pressed against the optical fiber core wire to cut a part of the coating and the optical fiber. Initial scratches are formed on the body (bare optical fiber).
Next, the optical fiber core wire is cut by applying a large tension to the optical fiber core wire to grow an initial flaw.
In this cutting method, since the coating is not removed, the above-described cost increase and disconnection problems are less likely to occur.

JP-A-62-194204

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

  The present invention has been made in view of the circumstances described above, and an object of the present invention is to provide an optical fiber cutting method and an optical fiber cutter capable of forming an initial scratch on an optical fiber easily and with high accuracy and obtaining a good cut surface. And

In order to solve this problem, in the present invention, the coated optical fiber whose side surface of the optical fiber body is covered with a coating is placed on the mounting surface of the mounting table, and a tensile force is applied to the coated optical fiber, By cutting the coated optical fiber by cleaving the coated optical fiber on the mounting surface by pressing a cutting tool against the coated optical fiber to form an initial scratch on the optical fiber body, the tensile force has the initial scratch. An optical fiber cutting method having a tensile force that can 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 1 MPa to 3 MPa at least at a portion where the optical fiber is mounted.
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 is 0.6 mm / s or less.
The angle of the cross section at the tip of the blade is preferably 45 to 90 °.
The pressing force when pressing the cutting tool against the optical fiber body is preferably 1 to 8N.

  The present invention includes a mounting table having a mounting surface on which a coated optical fiber whose side surface is covered with a coating, a tension applying mechanism that applies a tensile force to the coated optical fiber, An initial flaw is formed on the side surface of the optical fiber main body by pressing against the coated optical fiber placed on the surface, and a cutting tool for urging the optical fiber main body to be cut, and the tension applying mechanism. An optical fiber cutter comprising: a moving mechanism that moves the cutting tool toward the coated optical fiber on the mounting surface, to which a tensile force capable of cutting the optical fiber body by cleavage is provided. To do.

The mounting surface is a receiving convex portion that protrudes in a direction approaching the cutting tool, and the outer surface with which the optical fiber contacts is preferably a curved surface.
The static friction coefficient of the mounting surface is preferably 2 or less.
It is preferable that the mounting table is movable toward and away from the cutting tool and is biased toward the cutting tool by biasing means.
The optical fiber cutter of the present invention further includes a base body that holds the cutting tool, and the cutting tool is movable in a direction approaching the placement surface by pressing by a pressing body attached to the base body, and the pressing body However, it is preferable that the screw-type pressing tool is configured to be capable of pressing the blade tool by screw-feeding the screw shaft portion by a rotating operation.

According to the optical fiber cutting method and the optical fiber cutter according to the present invention, an initial flaw is formed on the optical fiber body by pressing the blade 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 at an appropriate depth, the initial flaw grows due to the tensile force, and the optical fiber is cut by cleavage. Therefore, the depth of the initial flaw does not become insufficient or excessive, and the cutting of the optical fiber body proceeds smoothly.
Therefore, an initial flaw is formed in the optical fiber easily and with high accuracy, and a good cut surface can be obtained.

It is a schematic diagram which shows the optical fiber cutter which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows operation | movement of the optical fiber cutter of FIG. It is explanatory drawing which shows operation | movement of the optical fiber cutter of FIG. It is a schematic diagram which shows the relationship between a blade and an optical fiber, (a) shows the stage which formed the initial stage damage | wound, (b) shows the stage which the cutting | disconnection of the optical fiber was completed. It is a schematic diagram which shows the structure of an optical fiber. It is a perspective view which shows the optical fiber cutter which concerns on the 2nd Embodiment of this invention. It is a disassembled perspective view which shows the optical fiber connector of FIG. It is sectional drawing which follows the XY plane of the optical fiber connector of FIG. It is an enlarged view which shows a blade tool and a mounting base. It is sectional drawing which follows the YZ plane of the optical fiber connector of FIG. It is explanatory drawing which shows the effect | action of a tension | tensile_strength provision mechanism. It is explanatory drawing which shows operation | movement of the optical fiber cutter of FIG. It is explanatory drawing which shows operation | movement of the optical fiber cutter of FIG. It is explanatory drawing which shows operation | movement of the optical fiber cutter of FIG. It is explanatory drawing which shows operation | movement of the optical fiber cutter of FIG.

(First 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, and the optical fiber 9 shown here is a coating having a configuration in which the outer peripheral surface (side surface) of the optical fiber main body 9a (bare optical fiber) is covered with a coating 9b. An attached optical fiber, for example, a single-core optical fiber or an optical fiber.
The optical fiber main body 9a (bare optical fiber) is, for example, a quartz optical fiber. The coating 9b is a single-layer or multiple-layer resin coating made of, for example, an ultraviolet curable resin (such as a urethane acrylate resin) or a polyamide resin.

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 that applies a tensile force to the optical fiber 9, and an optical fiber 9. A cutting tool unit 4 (cutting tool part) that forms an initial flaw and a moving mechanism 5 that moves the cutting tool unit 4 in a direction approaching and separating from the mounting table 2 are provided.
Hereinafter, “upper” and “lower” 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 2 a on which the optical fiber 9 is mounted. The mounting surface 2a can be a curved surface that protrudes upward. The mounting surface 2a may be, for example, a curved surface having a substantially arc shape or elliptic arc shape in cross section.
By making the mounting surface 2a a curved convex surface, the optical fiber 9 can be supported on the top of the mounting surface 2a, and when the optical fiber 9 is cut by the cutting tool unit 4, the pressing force of the cutting tool 16 can be applied as light. The fiber 9 can be reliably acted on.

It is preferable that at least a part of the mounting table 2 on which the optical fiber 9 is mounted is made of, for example, plastic and 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 slightly deforms to absorb the variation in the pressing force, so that an appropriate depth is obtained. Can form initial scratches. Further, by setting the Young's modulus to 1 MPa or more, a cut surface perpendicular (or substantially perpendicular) to the optical axis direction can be stably formed.
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 reliably applied to the optical fiber 9, and sufficient An initial flaw 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, the pressing load of the cutting tool 16 is set to an appropriate range, an initial flaw of an appropriate depth is formed, and a good cut surface can be obtained. it can.
The placement surface 2a is not limited to a curved surface, and may be a flat surface.

  The tension applying mechanism 3 includes a fixing portion 10 that fixes the first fixing portion 9A of the optical fiber 9, an optical fiber holder 11 that holds 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 the direction of separation.

  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 employed.

The optical fiber holder 11 includes a base portion 21 and a lid body 22 provided to be rotatable with respect to the base portion 21. The lid 22 can hold the second fixing portion 9 </ b> B of the optical fiber 9 with the base portion 21 interposed therebetween.
The second fixed portion 9B is a portion that is separated from the first fixed portion 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 fixed portion 10. As a structure that enables the optical fiber holder 11 to move in the direction, for example, an installation base (not shown) having a groove-like rail portion along the direction may be used. The rail portion 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 coincides with 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 placed on the mounting table 2 at an intermediate position between the first fixed location 9A and the second fixed location 9B.

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

The blade unit 4 includes a blade 16, a base 17 disposed away from the blade 16, and a spring 18 that urges the blade 16 in a direction approaching the optical fiber 9 (downward in FIG. 1) by applying a reaction force to the base 17. (Biasing means).
The cutting 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 2a of the mounting table 2, and has a thickness that increases toward the tip, for example. It can be formed with a sharp cross-sectional shape that reduces. The cutting tool 16 can be formed in a wedge shape, for example.

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

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

As the moving mechanism 5, it is preferable to employ 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) that is driven thereby to move the base 17 up and down via the connecting arm 23, and a control unit (not shown) that controls the rotational speed of the motor. Abbreviated).
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.
In addition, the drive mechanism used for the moving mechanism 5 is not limited to a motor, and may be another drive mechanism (a spring or the like). Further, a structure in which the operator manually moves the blade unit 4 up and down may be employed.

Next, an optical fiber cutting method for cutting the optical fiber 9 using the optical fiber cutter 1 will be described.
(Tensioning process)
As shown in FIG. 1, the first fixing portion 9 </ b> A of the optical fiber 9 is fixed to the fixing portion 10, and the second fixing portion 9 </ b> B is sandwiched and held between the base portion 21 of the optical fiber holder 11 and the lid body 22. To do. At this stage, the movement of the optical fiber holder 11 in the direction away from the fixed portion 10 may be restricted.
The optical fiber 9 is placed on the placement surface 2a of the placement table 2 at an intermediate position between the first fixed location 9A and the second fixed location 9B.

Next, as shown in FIG. 2, the optical fiber holder 11 is moved. As a result, the optical fiber holder 11 is moved in the direction away from the fixed portion 10 by the pressing force of the spring 12 (rightward in FIG. 2), and a tensile force is applied to the optical fiber 9.
It is desirable that the movement of the optical fiber holder 11 in the direction of the fixed portion 10 is restricted by the stopper 24 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.

When the optical fiber main body 9a (bare optical fiber) has an initial flaw, the tensile force applied to the optical fiber 9 is a force capable of growing the initial flaw and cutting the optical fiber main body 9a by cleavage.
The tensile force is preferably 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 optical fiber 9 may be cut. If the tensile force is too large, the cut surface may not be satisfactory. A good cut surface can be obtained.
The tensile force may vary within the above range, but is preferably constant in this step and the next step.
At this stage, the blade 16 is not in contact with the optical fiber 9.

(Initial scratch formation process)
Next, as shown in FIG. 3, the blade unit 4 is lowered by the moving mechanism 5, and the tip of the blade 16 is pressed against the side surface of the coating 9b of the optical fiber 9 on the mounting surface 2a. As a result, the optical fiber 9 is sandwiched between the placement surface 2 a 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 body 9a (bare optical fiber).
As shown in FIG. 4A, when the blade 16 is further lowered, an initial flaw 9c is formed by the blade 16 on the side surface of the optical fiber main body 9a (bare optical fiber).

The descending speed of the blade unit 4 is preferably 0.6 mm / s or less. If the descending speed is too fast, the initial scratch becomes too deep and it becomes difficult to obtain a good cut surface. However, by setting the descending speed to the above range, the optical fiber body 9a (bare optical fiber) has a suitable 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 because the working efficiency is lowered if it is too slow.

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

The pressing force when the cutting tool 16 is pressed against the optical fiber main body 9a (bare optical fiber) is preferably 1 N or more.
By setting the pressing force within this range, an initial flaw having an appropriate depth can be 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, since the tensile force is applied to the optical fiber 9 by the tension applying mechanism 3 as described above, the depth of the initial scratch formed in the optical fiber main body 9a (bare optical fiber). When the height dimension reaches a predetermined size (for example, 5 μm to 20 μm), initial scratches grow due to the tensile force, and the optical fiber body 9a (bare optical fiber) is cut by cleavage.
When the optical fiber body 9a (bare optical fiber) is cut, the tensile force also acts on the uncut portion of the coating 9b, and the coating 9b is also cut.
Reference numeral 9 d is a cut surface of the cut optical fiber 9. The cut surface 9d is preferably perpendicular to the axial direction of the optical fiber body 9a.

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

(Second Embodiment)
Next, the optical connector 20 which is the 2nd Embodiment of this invention is demonstrated 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-rear direction and 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. Note that the same components as those in the first embodiment described above 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 an optical fiber 9, a mounting table 25, a tension applying mechanism 26 that applies 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 in a direction approaching and separating from the mounting table 25 are provided.

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

The outer surface 25b2 of the top portion 25b1 is a placement surface (contact surface) on which the optical fiber 9 is placed.
The “placement” here is not limited to the case where the optical fiber 9 is placed on the optical fiber 9 but refers to the contact of the optical fiber 9 when the cutting tool 16 is pressed.

Since the outer surface 25b2 of the top portion 25b1 is a curved surface, the optical fiber 9 comes into contact with a small area.
For this reason, the frictional force in the state where the optical fiber 9 is pressed against the receiving convex portion 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 applied to the optical fiber 9.

The curvature radius of the cross section (XY cross section) of the outer surface 25b2 of the top portion 25b1 can be set to 5 mm or less, for example.
If the radius of curvature is too small, the direction and magnitude of the pressing force of the blade 16 acting on the optical fiber 9 may greatly vary when the position of the blade 16 relative to the mounting table 25 is shifted in the X direction. If the curvature radius is too large, the frictional force in the state where the optical fiber 9 is pressed against the receiving convex portion 25b by the cutting tool 16 becomes large.
On the other hand, by setting the radius of curvature within this range, the direction and magnitude of the pressing force acting on the optical fiber 9 does not vary greatly even when the position of the blade 16 relative to the mounting table 25 is shifted in the X direction. 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 convex portion 25 b by the cutting tool 16 can be reduced, a sufficient tensile force can be applied to the optical fiber 9.
Further, since the outer surface 25b2 of the top portion 25b1 is not a sharp shape but a curved surface, the direction and magnitude of the pressing force acting on the optical fiber 9 even if the position of the blade 16 relative to the mounting table 25 is shifted in the X direction. Does not fluctuate significantly.

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

The receiving convex portion 25b is made of, for example, plastic, 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 convex portion 25b with respect to the pressing force of the cutting tool 16 is suppressed, and the pressing load of the cutting tool 16 is surely applied to the optical fiber 9 to obtain a sufficient depth. Can form initial scratches.

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

The mounting table 25 is movable in a direction approaching and separating from the cutting tool 16. For this reason, by appropriately setting the elastic force of the first spring 30, it is possible to prevent the pressing force applied to the optical fiber 9 by the cutting tool 16 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 relaxed and the cut surface of the optical fiber 9 can be improved.

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

The first optical fiber holder 32 includes a first base portion 35 and a first lid body 36 that is hinged to the first base portion 35.
The first base portion 35 includes a base portion main body 35d and wall portions 35a provided at the front end and the 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 portion 35a.
The first lid 36 can hold the first fixing portion 9 </ b> A of the optical fiber 9 between the first base portion 35 and the first lid 36.

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

As shown in FIG. 8, the 2nd spring 40 consists of elastic members, such as a coil spring and a leaf | plate spring, for example.
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 portion 43.

The tension adjusting mechanism 39 includes a substantially disc-shaped cam portion 42 and a handle 41 that extends outward from the cam portion 42.
The cam portion 42 is attached to the frame portion 46 of the base 28 so as to be rotatable via a rotation shaft 42a at an eccentric position.

FIG. 11 is an explanatory view showing the operation of the tension adjusting mechanism 39.
As shown in FIG. 11A, when the handle 41 is directed 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 In this state, there is a gap between the inner surface 46 a 1 of the opening 46 a of the frame portion 46 and the outer surface 35 c of the first base portion 35 of the first optical fiber holder 32.

  As shown in FIG. 11B, when the handle 41 is rotated and directed in the X direction, the cam portion 42 rotates about the rotation shaft 42 a to release the pressure on the first optical fiber holder 32. Can do. 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 (left side 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 part 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 blade 16 is preferably made of ceramic or titanium-coated metal. As the blade 16, an NT blade may be adopted.
The cutting tool 16 is provided such that the tip portion protrudes from the cutting tool support portion 44.

The base body 28 is provided with a block-shaped base portion 43, a holder mounting base 45 on one side of the base portion 43 on which the second optical fiber holder 33 is placed, and a first side provided on the other side of the base portion 43. And a frame portion 46 that holds the optical fiber holder 32.
The base portion 43 is formed with a blade storage portion 47 that stores the blade unit 27 and a mounting table storage portion 48 that stores the mounting table 25.

The holder mounting base 45 is formed with a mounting recess 45 a that holds the second optical fiber holder 33. The mounting recess 45a is formed in a groove shape along the X direction.
The holder installation base 45 is formed with a restriction wall portion 45 b that restricts the second optical fiber holder 33 from moving in a direction approaching the first optical fiber holder 32. The regulation wall 45b is formed with a passage recess 45c through which the optical fiber 9 passes.

The dimension in the X direction of the opening 46 a of the frame part 46 is larger than the dimension in the X direction of the first optical fiber holder 32. For this reason, the frame part 46 can hold | maintain the 1st optical fiber holder 32 in the state which can move to the direction (X direction) which approaches and separates from the 2nd optical fiber holder 33. FIG.
The frame portion 46 is preferably formed so that the height of the first positioning groove 35b of the first optical fiber holder 32 and the height of the second positioning groove 37b of the second optical fiber holder 33 coincide with each other.

As shown in FIG. 8, the blade housing portion 47 is formed with a hole 47 a into which the blade support portion 44 is inserted.
The mounting table accommodating portion 48 is formed with a hole 48 a (see FIG. 10) that accommodates the mounting table 25 and the first spring 30.

As shown in FIG. 10, the moving mechanism 29 includes a pressing body 52 and a support portion 51 that supports the pressing body 52.
The pressing body 52 includes a screw shaft portion 49 and a head portion 50 provided at one end thereof. The screw shaft portion 49 is formed with a male screw 49 a that is screwed with a female screw surface 51 b formed in the insertion hole 51 a 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 can press the cutting tool support portion 44 when the screw shaft portion 49 is screw-fed by a rotation operation in the direction around the axis.
By using the pressing body 52 that employs a screw-type pressing mechanism, the operation for moving the blade support 44 is simplified, and the adjustment of the moving speed of the blade 16 is facilitated.
The moving mechanism 29 has a structure in which the pressing body 52 indirectly presses the blade 16 via the blade support 44, but the pressing body 52 may have a structure in which the blade 16 is directly pressed.

Next, a method for cutting the optical fiber 9 using the optical fiber cutter 20 will be described.
(Tensioning process)
As shown in FIG. 12, the handle 41 of the tension adjusting mechanism 39 is directed in the Y direction, the first optical fiber holder 32 is pressed toward the base portion 43 by the cam portion 42, and comes into contact with (or close to) the base portion 43. Let the state be
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 portion 37 and the second lid 38.
The optical fiber 9 abuts (or approaches) the outer surface 25b2 of the top portion 25b1 of the receiving convex portion 25b of the mounting table 25 at a location between the first fixed location 9A and the second fixed location 9B.

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

As in the first embodiment, the tensile force applied to the optical fiber 9 is preferably 50 to 800 gf (0.49 to 7.84 N). The tensile force is preferably more than 50 gf and not more than 800 gf, more preferably 200 to 500 gf. Of these, 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 flaw becomes too deep, and if the tensile force is too large, the fracture (crack formation) proceeds faster than the initial flaw grows, resulting in good cutting. 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, when the moving speed (advance speed) of the cutting tool 16 is high, in order to obtain a good cut surface, a large tensile force is required compared to an uncoated optical fiber. There is a case.
This is because when the moving speed (advance speed) of the cutting tool 16 is high, the cutting of the coating 9b may be delayed with a small tensile force.
On the other hand, when the moving speed (advance speed) of the cutting tool 16 is low, the tensile force required to obtain a good cut surface is almost the same as that of an uncoated optical fiber.
This is because if the moving speed (advance speed) of the cutting tool 16 is low, even if the tensile force is small, it can be sufficiently applied to the covering 9b, so that the cutting delay of the covering 9b hardly occurs.

(Initial scratch formation process)
Next, as shown in FIG. 14, the pressing body 52 is advanced by grasping the head 50 of the moving mechanism 29 and rotating it around the axis, and the cutting tool support portion 44 is pressed by the tip of the screw shaft portion 49. 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 convex portion 25b.
The tip 16a of the blade 16 is cut into the coating 9b, reaches the optical fiber main body 9a (bare optical fiber), and forms an initial flaw 9c on the side surface of the optical fiber main body 9a.

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

By suppressing the moving speed, many portions of the coating 9b can be cut before the initial scratch formed on the optical fiber body 9a (bare optical fiber) is deepened. This is because the tensile force applied can be sufficiently applied to the coating 9b.
On the other hand, if the moving speed of the cutting tool 16 is too fast, 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 0.6 mm / s or less, as in the first embodiment.
Thereby, before the optical fiber main body 9a (bare optical fiber) is cut, the covering 9b can be cut in a wide circumferential range (preferably over the entire circumference).
The lowering speed of the blade unit 4 is preferably 0.3 mm / s or more because the working efficiency is lowered if it is too slow.

The pressing force when the cutting tool 16 is pressed against the optical fiber main body 9a (bare optical fiber) is preferably 1 N or more, as in the first embodiment.
By setting the pressing force within this range, an initial flaw having an appropriate depth can be 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 scratch formed in the optical fiber main body 9a (bare optical fiber) is a predetermined size. At the stage of becoming (for example, 5 μm to 20 μm), initial scratches grow due to the tensile force, and the optical fiber body 9a (bare optical fiber) is cut by cleavage.
As the optical fiber 9 is cut, the first optical fiber holder 32 moves in a direction away from the base portion 43 (in the direction of the arrow) by the urging force of the second spring 40.
The first optical fiber holder 32 moves until the outer surface 35 c contacts the inner surface 46 a 1 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, an initial flaw is formed in the optical fiber main body 9a by pressing the cutting tool 16 against the side surface of the optical fiber 9 by the moving mechanism 29.
When the initial flaw is formed at an appropriate depth, the initial flaw grows due to the tensile force, and the optical fiber 9 is cut by cleavage. Therefore, the depth of the initial flaw does not become insufficient or excessive, and the cutting of the optical fiber body 9a proceeds smoothly.
Therefore, an initial flaw is formed in the optical fiber 9 easily and with high accuracy, and a good cut surface can be obtained.

In the optical fiber cutting method of the present embodiment, the optical fiber 9 is cut by the cutting tool 16 in a state where a sufficient tensile force is applied to the optical fiber 9, so that the moving speed (advance speed) of the cutting tool 16 is kept within a predetermined range. Then, many parts of the coating 9b can be cut before the optical fiber body 9a (bare optical fiber) is cut.
For example, before the optical fiber main body 9a (bare optical fiber) is cut, the coating 9b may be cut not only in a part in the circumferential direction of the coating 9b but also in a wide range in the circumferential direction (preferably over the entire circumference). it can.
For this reason, an initial flaw can be formed in the optical fiber main body 9a under the same conditions whether the target optical fiber is a coated optical fiber or an optical fiber from which the coating has been removed.
Therefore, this optical fiber cutting method can be commonly used for both the coated optical fiber and the coated optical fiber.

In the present invention, in the state where a tensile force is applied to the coated optical fiber placed on the mounting surface, an initial flaw is formed on the optical fiber body by pressing a cutting tool against the coated optical fiber, whereby the tensile force The optical fiber may be cleaved and cut.
The optical fiber cutting method of the present invention can also be applied to the case of cutting an optical fiber with the optical fiber body 9a exposed by removing the coating 9b of the coated optical fiber 9.
Further, the blade unit 27 shown in FIG. 8 and the like includes a blade support part 44, the blade 16 supported by the blade unit, and a spring (biasing means) that biases the blade 16 in a direction approaching the mounting table 25. It is good also as a structure.

DESCRIPTION OF SYMBOLS 1,20 ... Optical fiber cutter, 2,25 ... Mounting stand, 2a, 25b1 ... Mounting surface, 3 ... Fixing part, 4,26 ... Tension applying mechanism, 5,27 ... Cutting tool unit (cutting tool part), 6,29 DESCRIPTION OF SYMBOLS Movement mechanism, 9 ... Optical fiber (coated optical fiber), 9a ... Optical fiber body (bare optical fiber), 9b ... Covered, 9c ... Initial scratch, 11 ... Optical fiber holder, 12 ... Spring, 16 ... Cutting tool, 25b ... receiving convex part, 30 ... first spring (biasing means), 32 ... first optical fiber holder (fixing part), 33 ... second optical fiber holder.

Claims (11)

Place the coated optical fiber covering the side 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 cleaved by pressing a cutting tool against the coated optical fiber on the mounting surface to form an initial scratch on the optical fiber body. The optical fiber cutting method, wherein the tensile force is such a tensile force that the optical fiber body having an initial flaw can be cut by cleavage.   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 or 2, wherein the mounting surface of the mounting table has a Young's modulus of 1 MPa to 3 MPa at least at a portion where the optical fiber is mounted.   The optical fiber cutting method according to any one of claims 1 to 3, wherein when the cutting tool is pressed against the coated optical fiber, the moving speed of the cutting tool in the pressing direction is 0.6 mm / s or less.   The optical fiber cutting method according to any one of claims 1 to 4, wherein an angle of a cross section of a tip of the blade is 45 to 90 °.   The optical fiber cutting method according to any one of claims 1 to 5, wherein a pressing force when pressing the cutting tool against the optical fiber body is 1 to 8N. A mounting table having a mounting surface on which the coated optical fiber covering the side surface of the optical fiber body with a coating is mounted;
A tension applying mechanism for applying a tensile force to the coated optical fiber;
A cutting tool that forms an initial flaw on the side surface of the optical fiber main body to promote cutting of the optical fiber main body by being pressed against the coated optical fiber placed on the mounting surface.
A moving mechanism for moving the cutting tool toward the coated optical fiber on the placement surface, wherein the tension applying mechanism gives a tensile force enough to cut the optical fiber body having an initial flaw by cleavage. And an optical fiber cutter.   The optical fiber cutter according to claim 7, wherein the placement surface is an outer surface of a receiving convex portion protruding in a direction approaching the cutting tool, and an outer surface on which the optical fiber contacts is a curved surface.   The optical fiber cutter according to claim 7 or 8, wherein the static friction coefficient of the mounting 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 cutting tool and is biased toward the cutting tool by a biasing unit. Cutter. A base for holding the blade;
The cutting tool is movable in a direction approaching the placement surface by pressing with a pressing body attached to the base body,
The optical fiber cutter according to any one of claims 7 to 10, wherein the pressing body is a screw-type pressing tool that is capable of pressing the blade tool by a screw feeding operation of the screw shaft portion by a rotation operation. .

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