JP6993643B2 - Fixing structure and fixing method - Google Patents

Description

The present invention relates to a fixing structure and a fixing method, and more particularly to a fixing structure and a fixing method of a strand with an optical fiber.

Conventionally, an optical fiber having a strain sensor unit is attached to a tensile steel material, light is incident from the end of the optical fiber, and the light reflected from the strain sensor is measured at the end of the optical fiber to measure the position of the strain sensor. A measuring method for measuring the tension received by a tensile steel material is known (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2001-318011

In recent years, strands having one or more PC steel stranded wires installed in holes of various structures (bridges, buildings, slopes, etc.) as objects to be fixed, and optical fibers provided along the strands. Using a strand with an optical fiber having, the tension of the PC steel stranded wire is measured based on the strain of the optical fiber at each position in the extending direction of the optical fiber. The technique for measuring the tension distribution of the PC steel stranded wire based on the strain of the optical fiber is, for example, due to the movement of the anchor body connected to the PC steel stranded wire during tensioning and re-tensioning after the tension of the PC steel stranded wire. It is a useful technique such as being able to discriminate between a decrease in tension and a decrease in tension due to elongation of PC steel stranded wire.

In the technical field related to the fixing structure, conventionally, a crimping sleeve is crimped to a strand, and the inner peripheral surface of the crimping sleeve is crimped to the strand to form a strand holding portion for holding the strand, and the outer peripheral surface of the crimped sleeve is crimped. There is known a fixing structure in which a nut is screwed into a nut and the nut is tightened and fixed in a state where the strand is tensioned by a jack or the like. The fixing structure using such a nut has an advantage that the set loss at the time of fixing is small and the re-tensioning can be easily performed as compared with the fixing structure using a wedge, for example.

However, when the optical fiber-attached strand is fixed by the conventional fixing structure, when the optical fiber is arranged between the optical fiber-attached strand and the crimping sleeve, the optical fiber may be damaged by the crimping of the crimping sleeve.

Therefore, an object of the present invention is to provide a fixing structure and a fixing method capable of fixing a strand with an optical fiber by using a nut while suppressing damage to the optical fiber.

In the fixing structure according to the present invention, a strand with an optical fiber having a strand having one or more PC steel twisted wires installed in a hole of an object to be fixed and an optical fiber provided along the strand is formed at the edge of the hole. It is a fixing structure to be fixed to the surface to be fixed including, and the nut supported by the edge of the hole on the surface to be fixed and the inner peripheral surface are crimped to the strand to hold the strand, and the nut is screwed on the outer peripheral surface. A matching strand holding portion is provided, and the strand holding portion is provided with an optical fiber insertion passage through which an optical fiber peeled from a strand with an optical fiber is inserted in a portion other than the inner peripheral surface of the strand holding portion. ..

In this fixing structure, the inner peripheral surface of the strand holding portion is crimped to the strand so that the strand holding portion holds the strand, and the nut screwed to the outer peripheral surface of the strand holding portion is the edge of the hole on the fixed surface. Supported by. As a result, the strand with an optical fiber is fixed to the surface to be fixed. In this structure, an optical fiber insertion passage through which the optical fiber peeled from the strand with the optical fiber is inserted is provided in a portion other than the inner peripheral surface of the strand holding portion. As a result, it is possible to prevent the optical fiber from being strongly pressed by the inner peripheral surface of the strand holding portion crimped to the strand. Therefore, according to this fixing structure, it is possible to fix the strand with an optical fiber by using a nut while suppressing damage to the optical fiber.

In the anchoring structure according to the present invention, the strand holding portion may include an inner sleeve that is crimped to the strand and an outer sleeve that is arranged around the inner sleeve and screwed into the nut. When the inner sleeve is crimped to the PC steel stranded wire, residual stress is generated in the inner sleeve. For example, if the residual stress of the inner sleeve due to crimping is large and it is not easy to make an asymmetrical process around the axis of the inner sleeve into the inner sleeve, provide an outer sleeve that is placed around the inner sleeve and screwed into the nut. Therefore, it is possible to prevent irregular deformation of the inner sleeve due to residual stress. As a result, the holding force of the strand holding portion for holding the strand can be stabilized.

In the fixing structure according to the present invention, an outer sleeve groove extending along the axial direction of the outer sleeve is provided on at least one of the inner peripheral surface and the outer peripheral surface of the outer sleeve, and the optical fiber insertion passage is provided with the outer sleeve groove. May be. In this case, the optical fiber insertion passage can be more easily formed by forming a groove on at least one of the inner peripheral surface and the outer peripheral surface of the outer sleeve.

In the fixing structure according to the present invention, the base of the outer sleeve is provided with a through hole extending along the axial direction of the outer sleeve, and the optical fiber insertion passage may be a through hole. In this case, an optical fiber insertion passage can be formed by providing a through hole at the base of the outer sleeve.

In the fixing structure according to the present invention, the outer sleeve is composed of a plurality of dividing members arranged along the circumferential direction of the outer peripheral surface of the inner sleeve, and the optical fiber insertion passage is formed by the divided members adjacent to each other in the circumferential direction. It may be a gap of. In this case, since the plurality of divided members can be divided and processed, the processing can be easily performed.

In the fixing structure according to the present invention, a first screw portion is formed on the inner peripheral surface of the nut, and a second screw portion screwed to the first screw portion is formed on the outer peripheral surface of the outer sleeve. The optical fiber insertion passage may be a gap sandwiched between the first screw portion and the second screw portion. In this case, for example, it is possible to save the labor of processing such as forming a groove portion as an optical fiber insertion passage on the outer peripheral surface of the outer sleeve.

In the fixing structure according to the present invention, a third screw portion is formed on the inner peripheral surface of the outer sleeve, and a fourth screw portion screwed to the third screw portion is formed on the outer peripheral surface of the inner sleeve. The optical fiber insertion passage may be a gap sandwiched between the third screw portion and the fourth screw portion. In this case, it is possible to save the labor of processing such as forming a groove portion as an optical fiber insertion passage on the inner peripheral surface of the outer sleeve or the outer peripheral surface of the inner sleeve.

In the anchoring structure according to the present invention, the strand holding portion may include a sleeve that is crimped to the strand and screwed into the nut. In this case, it is possible to suppress an increase in the number of parts due to the provision of the optical fiber insertion passage.

The present invention can also be regarded as an invention of a fixing method, and the fixing method according to the present invention is along a strand and a strand having one or more PC steel twisted wires installed in a hole of an object to be fixed. A fixing method for fixing a strand with an optical fiber having an provided optical fiber to a surface to be fixed including an edge of a hole, in which an inner peripheral surface is crimped to the strand to provide a strand holding portion for holding the strand. The step of screwing the nut supported by the edge of the hole on the surface to be fixed to the outer peripheral surface of the strand holding portion, and the portion of the strand holding portion other than the inner peripheral surface of the strand holding portion from the strand with an optical fiber. A step of providing an optical fiber insertion passage through which the peeled optical fiber is inserted is provided.

In this fixing method, the inner peripheral surface of the strand holding portion is crimped to the strand so that the strand holding portion holds the strand, and the nut screwed to the outer peripheral surface of the strand holding portion is the edge of the hole on the fixed surface. Supported by. As a result, the strand with an optical fiber is fixed to the surface to be fixed. This method includes a step of providing an optical fiber insertion passage through which an optical fiber peeled from an optical fiber-attached strand is inserted in a portion other than the inner peripheral surface of the strand holding portion. As a result, it is possible to prevent the optical fiber from being strongly pressed by the inner peripheral surface of the strand holding portion crimped to the strand. Therefore, according to this fixing method, it is possible to fix the strand with an optical fiber by using a nut while suppressing damage to the optical fiber.

According to the present invention, a strand with an optical fiber can be fixed by using a nut while suppressing damage to the optical fiber.

FIG. 1 is a diagram showing an overall configuration of a ground anchor to which the fixing structure of the first embodiment is applied. FIG. 2 is a perspective view of a PC steel stranded wire with an optical fiber. FIG. 3 is a partial cross-sectional view of a main part of the fixing structure of FIG. FIG. 4 is a cross-sectional view of the optical fiber insertion passage of the fixing structure of FIG. FIG. 5 is a schematic view of the optical fiber insertion passage of FIG. FIG. 6 is a perspective view showing an example of the outer sleeve groove. FIG. 7 is a schematic view of the optical fiber insertion passage according to the second embodiment. FIG. 8 is a schematic view of the optical fiber insertion passage according to the third embodiment. FIG. 9 is a schematic view of the optical fiber insertion passage according to the fourth embodiment. FIG. 10 is a schematic view of the optical fiber insertion passage according to the fifth embodiment. FIG. 11 is a cross-sectional view of the optical fiber insertion passage according to the sixth embodiment. FIG. 12 is a cross-sectional view of the optical fiber insertion passage according to the seventh embodiment. FIG. 13 is a schematic view of the optical fiber insertion passage according to the eighth embodiment. FIG. 14 is a cross-sectional view of the optical fiber insertion passage according to the ninth embodiment. FIG. 15A is a schematic view of a modified example of the optical fiber insertion passage of FIG. FIG. 15B is a schematic diagram of another modification of the optical fiber insertion passage of FIG.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the description, the same reference numerals may be used for the same elements or elements having the same function, and duplicate description will be omitted. In the following description, words having front and back concepts such as "front end", "rear end", "front end", and "rear end" may be used. In this case, "front" corresponds to the lower part of the paper in FIGS. 1 and 3, and "rear" corresponds to the upper part of the paper in FIGS. 1 and 3.

[First Embodiment]
FIG. 1 is a diagram showing an overall configuration of a ground anchor to which the fixing structure of the first embodiment is applied. As shown in FIG. 1, the fixing structure 100 is a structure for fixing the strand 1 with an optical fiber to the fixed surface 102 of the object to be fixed 101. In the following, as an example, in a dam, a slope, etc., a ground anchor for pressing a fixed object 101, which is a structure such as a retaining wall provided on the bedrock R, against the bedrock R side to ensure mechanical stability. An example in which the fixing structure 100 is applied to 50 will be described.

The ground anchor 50 is installed inside the hole 103 drilled in the bedrock R and the object to be fixed 101. The ground anchor 50 includes a head 51 including a fixing structure 100, an anchor free length portion 52, an anchor body length portion 55, and a strand 1 with an optical fiber.

The strand 1 with an optical fiber has a strand 2 and an optical fiber member 20 provided along the strand 2. The strand 2 has a plurality of (7 in this embodiment) PC steel stranded wires 3 installed in the holes 103 of the object to be fixed 101. The strand 2 is a stranded wire formed by twisting a plurality of PC steel stranded wires 3. At least one of the plurality of PC steel stranded wires 3 in the strand 2 is the PC steel stranded wire 3 with an optical fiber.

FIG. 2 is a perspective view of a PC steel stranded wire 3A with an optical fiber. As shown in FIG. 2, the PC steel stranded wire 3A with an optical fiber has a PC steel stranded wire 3 and an optical fiber member 20 provided along the PC steel stranded wire 3. The PC steel stranded wire 3 is formed by twisting, for example, a plurality of PC steel strands 4 (7 in this embodiment) of the same diameter made of a steel material. The PC steel stranded wire 3A with an optical fiber is provided with at least one optical fiber member 20 along the one PC steel stranded wire 3. As an example, the PC steel stranded wire 3A with an optical fiber in the example of FIG. 2 is provided with two optical fiber members 20 along one PC steel stranded wire 3.

The optical fiber member 20 is installed in, for example, two of the twists 3a of the PC steel stranded wire 3 and extends spirally. The optical fiber member 20 has an optical fiber wire 21 and a coating 22 that covers the optical fiber wire 21.

Returning to FIG. 1, in the ground anchor 50, the front end side of the strand 1 with an optical fiber is inserted into the hole 103, and the rear end side of the strand 1 with an optical fiber protrudes rearward from the surface to be fixed 102.

The head 51 is provided in the opening of the hole 103 in the surface to be fixed 102 of the object to be fixed 101. The surface to be fixed 102 includes the edge portion 104 of the hole 103. The head 51 fixes the rear end portion of the strand 1 with an optical fiber to the object to be fixed 101 by the fixing structure 100.

The anchor free length portion 52 is a portion where the strand 1 with an optical fiber is not fixed on the front side from the surface to be fixed 102. The anchor free length portion 52 has a plate member 54 provided in the hole 103 of the object to be fixed 101. A strand 1 with an optical fiber is inserted through the plate member 54.

The anchor body length portion 55 is a portion where the front end portion of the strand 1 with an optical fiber is fixed on the front side from the surface to be fixed 102. In the anchor body length portion 55, for example, a plurality of load-bearing bodies 56 for fixing the front end portion of the strand 1 with an optical fiber are provided in series. The load-bearing body 56 has a load-bearing body main body 57 to which the front end portion of the optical fiber-attached strand 1 is fixed, and a reinforcing bar 58 provided behind the load-bearing body main body 57 so as to surround the optical fiber-attached strand 1. In the load-bearing body body 57 at the foremost end of the anchor body length portion 55, the strand 1 with an optical fiber is fixed to the bedrock R via the load-bearing body body 57. Reinforcing bars 58 are provided behind each load-bearing body body 57 to reinforce the strength of the filler 5 in the filler 5.

The hole 103 is filled with the filler 5 at the anchor free length portion 52 and the anchor body length portion 55. The filler 5 is, for example, cement milk, mortar, or the like, and is filled in the hole 103 and cured.

FIG. 3 is a partial cross-sectional view of a main part of the fixing structure of FIG. As shown in FIG. 3, the fixing structure 100 includes a nut 30 and a strand holding portion 40. The nut 30 is supported by the edge portion 104 of the hole 103 via the base portion 105 on the fixed surface 102 in a state where the strand 1 with an optical fiber is fixed to the fixed surface 102. The nut 30 is screwed into a threaded portion (described later) formed on the outer peripheral surface 40b of the strand holding portion 40.

The strand holding portion 40 is a member for holding the strand 2. The strand holding portion 40 holds the strand 2 so as to be tightened by crimping the inner peripheral surface 40a to the strand 2. Further, the strand holding portion 40 has a load bearing body 56 on the front end side of the strand 2 (strand 1 with an optical fiber) by tightening a nut 30 screwed to the outer peripheral surface 40b in a state where the strand 2 is tensioned by a jack or the like. It is fixed in the fiber and held in a state where tension is applied.

The strand holding portion 40 includes an inner sleeve 41 and an outer sleeve 42 as an example.

The strand 2 from which the optical fiber member 20 is peeled off from the strand 1 with an optical fiber is inserted into the inner sleeve 41. The inner sleeve 41 is crimped with the strand 2 inserted through the inner sleeve 41. As a result, the inner peripheral surface 41a of the inner sleeve 41 is crimped to the strand 2. The inner peripheral surface 41a of the inner sleeve 41 corresponds to the inner peripheral surface 40a of the strand holding portion 40. A threaded portion, which is a male screw, is formed on the outer peripheral surface 41b of the inner sleeve 41. The material of the inner sleeve 41 is, for example, a steel material.

The outer sleeve 42 is arranged around the inner sleeve 41. A threaded portion, which is a female screw, is formed on the inner peripheral surface 42a of the outer sleeve 42, and is screwed with the threaded portion on the outer peripheral surface 41b of the inner sleeve 41. A threaded portion, which is a male screw, is formed on the outer peripheral surface 42b of the outer sleeve 42. A nut 30 is screwed into the threaded portion of the outer peripheral surface 42b. That is, the inner peripheral surface 42a of the outer sleeve 42 corresponds to the outer peripheral surface 40b of the strand holding portion 40. The material of the outer sleeve 42 is, for example, a steel material. The outer diameter of the outer sleeve 42 is, for example, a screw diameter of one or several ranks higher (larger diameter dimension) than the standard of the screw portion formed on the outer peripheral surface 41b of the inner sleeve 41. As a result, existing standard products can be used for parts such as the nut 30. The outer sleeve 42 may be screwed with the inner sleeve 41 with a screw length that can support the tension force of the strand 1 with an optical fiber, and is the length of the inner sleeve 41 in the axial B direction (axial direction). It may be shorter than that. In this case, the threaded portion can be easily formed on the inner peripheral surface 42a of the outer sleeve 42.

The base portion 105 is a fixing plate that supports the tension force of the strand 1 with an optical fiber. The base portion 105 is in contact with the surface to be fixed 102 of the object to be fixed 101. The base portion 105 has a circular opening 105a through which the strand 1 with an optical fiber is inserted. The base portion 105 does not necessarily have to be provided.

In the strand holding portion 40, a force due to crimping acts between the inner peripheral surface 41a of the inner sleeve 41 and the strand 2 by crimping. Therefore, if the optical fiber member 20 is arranged between the inner peripheral surface 41a and the strand 2, the optical fiber member 20 may be damaged by the force of crimping. Therefore, the strand holding portion 40 is provided with an optical fiber insertion passage 10 through which the optical fiber member 20 peeled off from the strand 1 with an optical fiber is inserted in a portion other than the inner peripheral surface 40a of the strand holding portion 40.

FIG. 4 is a cross-sectional view of the optical fiber insertion passage 10 of the fixing structure 100. FIG. 5 is a schematic view of the optical fiber insertion passage 10 of FIG. As shown in FIGS. 4 and 5, the outer peripheral surface 42b of the outer sleeve 42 is provided with an outer sleeve groove 11 extending along the axis B direction of the outer sleeve 42. The cross-sectional shape of the outer sleeve groove 11 is, for example, a triangular shape. The outer sleeve groove 11 forms a space between the outer peripheral surface 42b of the outer sleeve 42 and the inner peripheral surface 30a of the nut 30. This space has a size that includes the optical fiber member 20. As a result, the outer sleeve groove 11 functions as the optical fiber insertion passage 10. The number of the outer sleeve grooves 11 is at least one, and corresponds to the number of the optical fiber members 20 peeled off from the strand 1 with the optical fiber. However, in this embodiment, for the sake of simplification of the drawings, only one number of outer sleeve grooves 11 as the optical fiber insertion passage 10 is shown.

FIG. 6 is a perspective view of the outer sleeve groove 11. As shown in FIG. 6, the outer sleeve groove 11 is formed so as to cut out the threaded portion of the outer peripheral surface 42b of the outer sleeve 42 in a V-shaped cross section along the axis B direction of the outer sleeve 42. Therefore, the outer sleeve groove 11 can be easily formed by processing from the outside of the outer sleeve 42. Further, since the outer sleeve 42 does not generate residual stress due to crimping unlike the inner sleeve 41, the outer sleeve groove 11 is formed on the outer peripheral surface 42b of the outer sleeve 42 without being affected by the residual stress. be able to.

Next, the fixing method according to the first embodiment will be described. In this fixing method, first, the first step of providing the strand holding portion 40 is performed. In this first step, for example, the strand 2 from which the optical fiber member 20 is peeled off from the strand 1 with an optical fiber is inserted into the inner sleeve 41. With the strand 2 inserted through the inner sleeve 41, a crimping force is applied from the outside of the inner sleeve 41. As a result, the inner peripheral surface 41a of the inner sleeve 41 is crimped to the strand 2. Further, in the first step, a threaded portion, which is a male screw, is formed on the outer peripheral surface 41b of the inner sleeve 41. Since the processing for forming the threaded portion is symmetrical processing around the axis B of the inner sleeve 41, irregular deformation of the inner sleeve 41 is less likely to occur as compared with the processing asymmetrical around the axis B of the inner sleeve 41.

In the first step, the outer sleeve 42 is prepared. Specifically, a screw portion to be screwed into the screw portion of the outer peripheral surface 41b of the inner sleeve 41 is formed on the inner peripheral surface 42a of the outer sleeve 42. A screw portion to be screwed into the screw portion of the inner peripheral surface 30a of the nut 30 is formed on the outer peripheral surface 42b of the outer sleeve 42. As each screw portion of the outer sleeve 42, for example, one that has been processed in advance at a factory or the like may be prepared. As a result, in the first step, the inner peripheral surface 40a of the strand holding portion 40 is crimped to the strand 2, so that the strand holding portion 40 for holding the strand 2 is provided.

Next, a second step of providing the optical fiber insertion passage 10 is performed. In the second step, the outer sleeve groove 11 is formed on the outer peripheral surface 42b of the outer sleeve 42. As the outer sleeve groove 11 of the outer sleeve 42, for example, one that has been processed in advance at a factory or the like may be prepared. Subsequently, the optical fiber member 20 peeled off from the strand 1 with the optical fiber is inserted into the outer sleeve groove 11. As a result, in the second step, the optical fiber insertion passage 10 through which the optical fiber member 20 peeled off from the optical fiber-attached strand 1 is inserted is provided in the portion of the strand holding portion 40 other than the inner peripheral surface 40a of the strand holding portion 40. It will be provided.

Next, a third step of fixing the strand 1 with an optical fiber to the surface to be fixed 102 is performed. In the third step, the nut 30 is screwed into the outer peripheral surface 42b of the outer sleeve 42 in a state where the optical fiber member 20 is inserted into the optical fiber insertion passage 10. By tightening the nut 30 after tensioning the strand 1 with an optical fiber with a jack or the like, the nut 30 is arranged so as to abut on the edge portion 104 of the hole 103 on the surface to be fixed 102 via the base portion 105. As a result, the nut 30 is supported by the edge portion 104 of the hole 103, and the strand 1 with an optical fiber is fixed to the surface to be fixed 102.

As described above, in the fixing structure 100 and the fixing method according to the first embodiment, the inner peripheral surface 40a of the strand holding portion 40 is crimped to the strand 2, so that the strand holding portion 40 holds the strand 2 and at the same time. The nut 30 screwed to the outer peripheral surface 40b of the strand holding portion 40 is supported by the edge portion 104 of the hole 103 on the surface to be fixed 102. As a result, the strand 1 with an optical fiber is fixed to the surface to be fixed 102. In the fixing structure 100 and the fixing method, an optical fiber insertion passage 10 through which the optical fiber member 20 peeled off from the optical fiber-attached strand 1 is inserted is provided in a portion other than the inner peripheral surface 40a of the strand holding portion 40. .. As a result, it is possible to prevent the optical fiber member 20 from being strongly pressed by the inner peripheral surface 40a of the strand holding portion 40 crimped to the strand 2. Therefore, according to the fixing structure 100 and the fixing method, it is possible to fix the strand 1 with an optical fiber by using the nut 30 while suppressing damage to the optical fiber member 20.

Further, in the fixing structure 100, the strand holding portion 40 includes an inner sleeve 41 that is crimped to the strand 2 and an outer sleeve 42 that is arranged around the inner sleeve 41 and screwed into the nut 30. When the inner sleeve 41 is crimped to the PC steel stranded wire 3, residual stress is generated in the inner sleeve 41. For example, when the residual stress of the inner sleeve 41 due to crimping is large and asymmetric processing around the axis B of the inner sleeve 41 is not easy, an outer sleeve 42 arranged around the inner sleeve 41 and screwed to the nut 30 is provided. Therefore, it is possible to avoid irregular deformation due to residual stress. As a result, the holding force of the strand holding portion 40 for holding the strand 2 can be stabilized.

Further, in the fixing structure 100, the outer peripheral surface 42b of the outer sleeve 42 is provided with an outer sleeve groove 11 extending along the axis B direction of the outer sleeve 42, and the optical fiber insertion passage 10 is the outer sleeve groove 11. be. As a result, the optical fiber insertion passage 10 can be more easily formed by forming a groove on the outer peripheral surface 42b of the outer sleeve 42.

[Second Embodiment]
The fixing structure 100 according to the second embodiment will be described with reference to FIG. 7. FIG. 7 is a schematic view of the optical fiber insertion passage 10 according to the second embodiment. In the fixing structure 100 according to the second embodiment, as shown in FIG. 7, instead of providing the outer sleeve groove 11 on the outer peripheral surface 42b of the outer sleeve 42, the outer sleeve is formed on the inner peripheral surface 42a of the outer sleeve 42. It differs from the first embodiment in that the outer sleeve groove 12 extending along the axis B direction of 42 is provided.

The outer sleeve groove 12 forms a space between the inner peripheral surface 42a of the outer sleeve 42 and the outer peripheral surface 41b of the inner sleeve 41. This space has a size that includes the optical fiber member 20. As a result, the outer sleeve groove 12 functions as the optical fiber insertion passage 10.

In the fixing structure 100 according to the second embodiment configured in this way, the outer sleeve groove 12 extending along the axis B direction of the outer sleeve 42 is provided on the inner peripheral surface 42a of the outer sleeve 42, and is optical. The fiber insertion passage 10 is an outer sleeve groove 12. As a result, the optical fiber insertion passage 10 can be more easily formed by forming a groove on the inner peripheral surface 42a of the outer sleeve 42.

[Third Embodiment]
The fixing structure 100 according to the third embodiment will be described with reference to FIG. FIG. 8 is a schematic view of the optical fiber insertion passage 10 according to the third embodiment. In the fixing structure 100 according to the third embodiment, as shown in FIG. 8, instead of providing the outer sleeve groove 11 on the outer peripheral surface 42b of the outer sleeve 42, the inner sleeve 41 is provided on the outer peripheral surface 41b of the inner sleeve 41. It is different from the first embodiment in that the inner sleeve groove 13 extending along the axis B direction of the above is provided.

For example, when the residual stress of the inner sleeve 41 due to crimping is small and asymmetric processing is possible around the axis B of the inner sleeve 41, light is applied between the outer peripheral surface 41b of the inner sleeve 41 and the inner peripheral surface 42a of the outer sleeve 42. An inner sleeve groove 13 may be provided to form a space having a size including the fiber member 20. As a result, the inner sleeve groove 13 functions as the optical fiber insertion passage 10.

In the fixing structure 100 according to the third embodiment configured in this way, the outer peripheral surface 41b of the inner sleeve 41 is provided with an inner sleeve groove 13 extending along the axis B direction of the inner sleeve 41, and is an optical fiber. The insertion passage 10 is an inner sleeve groove 13. As a result, for example, when the residual stress of the inner sleeve 41 due to crimping is small and asymmetric processing is possible around the axis B of the inner sleeve 41, instead of forming the optical fiber insertion passage 10 in the outer sleeve 42, By forming a groove on the outer peripheral surface 41b of the inner sleeve 41, the optical fiber insertion passage 10 can be formed.

[Fourth Embodiment]
The fixing structure 100 according to the fourth embodiment will be described with reference to FIG. 9. FIG. 9 is a schematic view of the optical fiber insertion passage 10 according to the fourth embodiment. In the fixing structure 100 according to the fourth embodiment, as shown in FIG. 9, instead of providing the outer sleeve groove 11 on the outer peripheral surface 42b of the outer sleeve 42, the outer sleeve 42 is provided on the base 42c of the outer sleeve 42. It differs from the first embodiment in that a through hole 14 extending along the axis B direction is provided. The base portion 42c of the outer sleeve 42 is a portion of the outer sleeve 42 sandwiched between the inner peripheral surface 42a and the outer peripheral surface 42b, and does not include the inner peripheral surface 42a and the outer peripheral surface 42b.

The cross-sectional shape of the through hole 14 is not particularly limited, but is, for example, circular. The through hole 14 forms a space in the base 42c of the outer sleeve 42. This space has a size that includes the optical fiber member 20. As a result, the through hole 14 functions as the optical fiber insertion passage 10.

In the fixing structure 100 according to the fourth embodiment configured in this way, the base portion 42c of the outer sleeve 42 is provided with a through hole 14 extending along the axis B direction of the outer sleeve 42, and the optical fiber insertion passage is provided. Reference numeral 10 is a through hole 14. As a result, the optical fiber insertion passage 10 can be formed by providing the through hole 14 in the base portion 42c of the outer sleeve 42.

[Fifth Embodiment]
The fixing structure 100 according to the fifth embodiment will be described with reference to FIG. 10. FIG. 10 is a schematic view of the optical fiber insertion passage 10 according to the fifth embodiment. In the fixing structure 100 according to the fifth embodiment, as shown in FIG. 10, instead of providing the outer sleeve groove 11 on the outer peripheral surface 42b of the outer sleeve 42, the outer sleeve 42 has the outer peripheral surface 41b of the inner sleeve 41. It is different from the first embodiment in that it is composed of a plurality of divided members 43 arranged along the circumferential direction of the above.

Both ends of the dividing member 43 in the circumferential direction are planar end faces extending along the radial direction of the strand 2. A gap 15 is formed between the divided members 43 adjacent to each other in the circumferential direction of the strand 2. The number of gaps 15 is at least one, which corresponds to the number of optical fiber members 20 peeled off from the strand 1 with optical fibers. In the gap 15, a space is formed between the adjacent split members 43, the outer peripheral surface 41b of the inner sleeve 41, and the inner peripheral surface 42a of the outer sleeve 42. This space has a size that includes the optical fiber member 20. As a result, the gap 15 functions as the optical fiber insertion passage 10.

In the fixing structure 100 according to the fifth embodiment configured in this way, the outer sleeve 42 is composed of a plurality of dividing members 43 arranged along the circumferential direction of the outer peripheral surface 41b of the inner sleeve 41, and is composed of light. The fiber insertion passage 10 is a gap between the dividing members 43 adjacent to each other in the circumferential direction. In this case, since the plurality of divided members 43 can be divided and processed, the processing can be easily performed.

[Sixth Embodiment]
The fixing structure 100 according to the sixth embodiment will be described with reference to FIG. 11. FIG. 11 is a cross-sectional view of the optical fiber insertion passage 10 according to the sixth embodiment. In the fixing structure 100 according to the sixth embodiment, as shown in FIG. 11, instead of providing the outer sleeve groove 11 on the outer peripheral surface 42b of the outer sleeve 42, the inner peripheral surface 30a of the nut 30 is the first. The threaded portion TH1 is formed, and the outer peripheral surface 42b of the outer sleeve 42 is different from the first embodiment in that a second threaded portion TH2 screwed to the first threaded portion TH1 is formed. ..

The height of the thread of the first threaded portion TH1 and the height of the thread of the second threaded portion TH2 are different from each other. For example, the top of the thread of the first threaded portion TH1 is formed in a flat shape, so that the height of the thread of the first threaded portion TH1 is smaller than the height of the thread of the second threaded portion TH2. .. In this case, the thread valley of the first screw portion TH1 and the thread of the second screw portion TH2 are configured to mesh with each other, and the outer sleeve 42 and the nut 30 can be screwed together.

The gap 16 sandwiched between the first screw portion TH1 and the second screw portion TH2 forms a space between the inner peripheral surface 30a of the nut 30 and the outer peripheral surface 42b of the outer sleeve 42. This space has a size that includes the optical fiber member 20. As a result, the gap 16 functions as the optical fiber insertion passage 10.

In the fixing structure 100 according to the sixth embodiment configured in this way, the first screw portion TH1 is formed on the inner peripheral surface 30a of the nut 30, and the first screw portion TH1 is formed on the outer peripheral surface 42b of the outer sleeve 42. A second screw portion TH2 screwed into the screw portion TH1 is formed, and the optical fiber insertion passage 10 is a gap 16 sandwiched between the first screw portion TH1 and the second screw portion TH2. As a result, it is possible to save the labor of processing such as forming a groove portion as the optical fiber insertion passage 10 on the outer peripheral surface 42b of the outer sleeve 42, for example. In this embodiment, the height of the thread of the second screw portion TH2 may be smaller than the height of the thread of the first screw portion TH1.

[7th Embodiment]
The fixing structure 100 according to the seventh embodiment will be described with reference to FIG. 12. FIG. 12 is a cross-sectional view of the optical fiber insertion passage 10 according to the seventh embodiment. In the fixing structure 100 according to the seventh embodiment, as shown in FIG. 12, the first screw portion TH1 is formed on the inner peripheral surface 30a of the nut 30, and the second screw portion TH2 is formed on the outer peripheral surface 42b of the outer sleeve 42. Instead of forming, a third screw portion TH3 is formed on the inner peripheral surface 42a of the outer sleeve 42, and a fourth screw portion TH3 screwed to the third screw portion TH3 is formed on the outer peripheral surface 41b of the inner sleeve 41. It differs from the sixth embodiment in that the threaded portion TH4 is formed.

The threads and threads of the third threaded portion TH3 are configured in the same manner as those of the first threaded portion TH1. The fourth screw portion TH4 screw thread and the screw valley are configured in the same manner as the fourth screw portion TH4. Therefore, a gap 17 sandwiched between the third screw portion TH3 and the fourth screw portion TH4 is formed, and the screw valley of the first screw portion TH1 and the screw thread of the second screw portion TH2 are configured to mesh with each other. , The outer sleeve 42 and the nut 30 can be screwed together.

The gap 17 sandwiched between the third screw portion TH3 and the fourth screw portion TH4 forms a space between the inner peripheral surface 42a of the outer sleeve 42 and the outer peripheral surface 41b of the inner sleeve 41. This space has a size that includes the optical fiber member 20. As a result, the gap 17 functions as the optical fiber insertion passage 10.

In the fixing structure 100 according to the seventh embodiment configured in this way, the third screw portion TH3 is formed on the inner peripheral surface 42a of the outer sleeve 42, and the outer peripheral surface 41b of the inner sleeve 41 is the third. A fourth screw portion TH4 screwed into the three screw portion TH3 is formed, and the optical fiber insertion passage 10 is a gap 17 sandwiched between the third screw portion TH3 and the fourth screw portion TH4. As a result, it is possible to save the labor of processing such as forming a groove portion as the optical fiber insertion passage 10 on the inner peripheral surface 42a of the outer sleeve 42 or the outer peripheral surface 41b of the inner sleeve 41. In this embodiment, the height of the thread of the second screw portion TH2 may be smaller than the height of the thread of the first screw portion TH1.

[Eighth Embodiment]
The fixing structure 100 according to the eighth embodiment will be described with reference to FIG. 13. FIG. 13 is a schematic view of the optical fiber insertion passage 10 according to the eighth embodiment. As shown in FIG. 13, the fixing structure 100 according to the eighth embodiment is crimped to the strand 2 and screwed to the nut 30 instead of the strand holding portion 40 including the inner sleeve 41 and the outer sleeve 42. The point that the strand holding portion 40 including the inner sleeve (sleeve) 41 is provided, and instead of providing the outer sleeve groove 11 on the outer peripheral surface 42b of the outer sleeve 42, the inner sleeve is formed on the outer peripheral surface 41b of the inner sleeve 41. It differs from the first embodiment in that the inner sleeve groove 13 extending along the axis B direction of 41 is provided.

For example, when the residual stress of the inner sleeve 41 due to crimping is small and asymmetric processing is possible around the axis B of the inner sleeve 41, an optical fiber is formed between the inner peripheral surface 30a of the nut 30 and the outer peripheral surface 41b of the inner sleeve 41. An inner sleeve groove 13 may be provided to form a space having a size including the member 20. As a result, the inner sleeve groove 13 functions as the optical fiber insertion passage 10.

In the fixing structure 100 according to the eighth embodiment configured in this way, the outer peripheral surface 41b of the inner sleeve 41 is provided with an inner sleeve groove 13 extending along the axis B direction of the inner sleeve 41, and is an optical fiber. The insertion passage 10 is an inner sleeve groove 13. As a result, for example, when the residual stress of the inner sleeve 41 due to crimping is small and asymmetric processing is possible around the axis B of the inner sleeve 41, a groove is formed on the outer peripheral surface 41b of the inner sleeve 41 to form an outer surface. It is possible to omit providing the sleeve 42. Therefore, it is possible to suppress an increase in the number of parts due to the provision of the optical fiber insertion passage 10.

[9th Embodiment]
The fixing structure 100 according to the ninth embodiment will be described with reference to FIG. FIG. 14 is a cross-sectional view of the optical fiber insertion passage 10 according to the ninth embodiment. In the fixing structure 100 according to the ninth embodiment, as shown in FIG. 14, instead of the strand holding portion 40 including the inner sleeve 41 and the outer sleeve 42, the fixing structure 100 is crimped to the strand 2 and screwed to the nut 30. The point that the strand holding portion 40 including the inner sleeve (sleeve) 41 is provided, and instead of forming the second screw portion TH2 on the outer peripheral surface 42b of the outer sleeve 42, the outer peripheral surface 41b of the inner sleeve 41 has a second thread. It differs from the sixth embodiment in that a second screw portion TH2 screwed to the first screw portion TH1 is formed.

Also in this case, as in the sixth embodiment, the gap 16 sandwiched between the first screw portion TH1 and the second screw portion TH2 is formed, and the screw valley and the second screw portion of the first screw portion TH1 are formed. The thread of TH2 is configured to mesh with the thread, and the inner sleeve 41 and the nut 30 can be screwed together.

The gap 16 sandwiched between the first screw portion TH1 and the second screw portion TH2 forms a space between the inner peripheral surface 30a of the nut 30 and the outer peripheral surface 41b of the inner sleeve 41. This space has a size that includes the optical fiber member 20. As a result, the gap 16 functions as the optical fiber insertion passage 10.

In the fixing structure 100 according to the ninth embodiment configured in this way, the first screw portion TH1 is formed on the inner peripheral surface 30a of the nut 30, and the first screw portion TH1 is formed on the outer peripheral surface 41b of the inner sleeve 41. A second screw portion TH2 screwed into the screw portion TH1 is formed, and the optical fiber insertion passage 10 is a gap 16 sandwiched between the first screw portion TH1 and the second screw portion TH2. As a result, it is possible to save the labor of processing such as forming a groove portion as the optical fiber insertion passage 10 on the outer peripheral surface 41b of the inner sleeve 41, and it is possible to suppress an increase in the number of parts due to the provision of the optical fiber insertion passage 10. can do. In this embodiment, the height of the thread of the second screw portion TH2 may be smaller than the height of the thread of the first screw portion TH1.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and may be modified without changing the gist described in each claim.

For example, the PC steel stranded wire 3 is not limited to the stranded wire having 7 PC steel strands 4 as in each of the above embodiments, and is, for example, a stranded wire having 19 PC steel strands 4 or another. It may be a stranded wire having a number of PC steel strands 4. Further, the strand 2 was composed of seven PC steel stranded wires 3 including at least one PC steel stranded wire 3A with an optical fiber, whereas the strand 2 has one or a plurality of optical fibers attached. It can be composed of PC steel stranded wire 3A and PC steel stranded wire 3. For example, the strand 2 may be composed of one PC steel stranded wire 3A with an optical fiber.

In the first embodiment, as shown in FIG. 4, the cross-sectional shape of the outer sleeve groove 11 is triangular (V-shaped cross-section), and as an example, the valley portion (tip portion) on the radial center side of the strand 2 is formed. ) Was formed as a shape forming an acute angle. However, the cross-sectional shape of the outer sleeve groove 11 is not limited to this. For example, the cross-sectional shape of the outer sleeve groove 11 can be deformed as shown in FIGS. 15A and 15B.

FIG. 15A is a schematic view of a modified example of the outer sleeve groove 11 of FIG. 4 as viewed from the axial direction of the strand 2. As shown in FIG. 15A, the cross-sectional shape of the outer sleeve groove 11 is, for example, a shape (boomerang shape) in which the valley portion (tip portion) on the radial center side of the strand 2 is rounded. You may. As a result, stress concentration in the valley portion of the outer sleeve groove 11 can be suppressed, and for example, generation and growth of cracks can be avoided.

FIG. 15B is a schematic view of another modification of the outer sleeve groove 11 of FIG. 4 as viewed from the axial direction of the strand 2. As shown in FIG. 15B, the cross-sectional shape of the outer sleeve groove 11 may be, for example, a U-shape. Also in this case, since the valley portion (tip portion) on the radial center side of the strand 2 is formed in a rounded shape, stress concentration in the valley portion of the outer sleeve groove 11 is suppressed, and for example, cracks are generated. And avoid progress.

The modifications shown in FIGS. 15 (a) and 15 (b) described above can be applied not only to the cross-sectional shape of the outer sleeve groove 11 of the first embodiment, but also to the outer sleeve groove 12 of the second embodiment (FIG. 7), the inner sleeve groove 13 (FIG. 8) of the third embodiment, and the inner sleeve groove 13 (FIG. 13) of the eighth embodiment can be similarly applied to each cross-sectional shape.

Further, although the outer sleeve 42 is integrally configured in the axis B direction, it may be divided into a plurality of members in the axis B direction, for example.

Further, the inner sleeve 41 and the outer sleeve 42 may be joined by, for example, grout or an adhesive instead of screwing the respective screw portions. In this case, the processing for forming the screw portion can be omitted.

Further, in the above embodiment, an example in which the outer sleeve grooves 11 and 12 are provided on either one of the inner peripheral surface 42a and the outer peripheral surface 42b of the outer sleeve 42 is shown, but the inner peripheral surface 42a and the outer peripheral surface 42b are provided. Outer sleeve grooves 11 and 12 may be provided on both sides. That is, outer sleeve grooves 11 and 12 extending along the axis B direction of the outer sleeve 42 may be provided on at least one of the inner peripheral surface 42a and the outer peripheral surface 42b of the outer sleeve 42.

Further, in each of the above embodiments, an example is shown in which one optical fiber insertion passage 10 is provided in a portion other than the inner peripheral surface 40a of the strand holding portion 40 in the strand holding portion 40 or the nut 30. A plurality of optical fiber insertion passages 10 may be provided by appropriately combining the above embodiments. The plurality of optical fiber insertion passages 10 in this case include, for example, a plurality of the same type among the outer sleeve groove 11, the outer sleeve groove 12, the inner sleeve groove 13, the through hole 14, the gap 15, the gap 16, and the gap 17. It may be composed of things, all of them may be made of different kinds, or some of them may be made of the same kind and the rest may be made of different kinds.

Further, in the optical fiber member 20, the optical fiber wire 21 is covered with the coating 22, but the periphery thereof may be further covered with a resin filler.

1 ... Strand with optical fiber, 2 ... Strand, 3 ... PC steel twisted wire, 10 ... Optical fiber insertion passage, 11 ... Outer sleeve groove, 12 ... Outer sleeve groove, 14 ... Through hole, 15, 16, 17 ... Gap, 20 ... Optical fiber member (optical fiber), 30 ... Nut, 30a ... Inner peripheral surface, 40 ... Strand holding portion, 40a ... Inner peripheral surface, 40b ... Outer peripheral surface, 41 ... Inner sleeve (sleeve), 41a ... Inner peripheral surface , 41b ... outer peripheral surface, 42 ... outer sleeve, 42a ... inner peripheral surface, 42b ... outer peripheral surface, 42c ... base, 43 ... divided member, 100 ... fixing structure, 101 ... fixed object, 102 ... fixed surface, 103 ... Hole, 104 ... edge portion, B ... shaft, TH1 ... first screw portion, TH2 ... second screw portion, TH3 ... third screw portion, TH4 ... fourth screw portion.

Claims (11)

A PC steel stranded wire with an optical fiber having a strand having one or more PC steel stranded wires installed in the hole of the object to be fixed and an optical fiber provided along the strand is covered with a PC steel stranded wire including the edge of the hole. It is a fixing structure that is fixed to the fixing surface.
A nut supported by the edge of the hole on the surface to be fixed,
The inner peripheral surface is crimped to the strand to hold the strand, and the outer peripheral surface is provided with a strand holding portion into which the nut is screwed.
The strand holding portion is provided with an optical fiber insertion passage through which the optical fiber peeled from the PC steel stranded wire with an optical fiber is inserted in a portion other than the inner peripheral surface of the strand holding portion .
The strand holder comprises a sleeve that is crimped to the strand and screwed into the nut.
A sleeve groove is provided on the outer peripheral surface of the sleeve, and the sleeve groove is provided.
The optical fiber insertion passage is a fixing structure that is the sleeve groove . A PC steel stranded wire with an optical fiber having a strand having one or more PC steel stranded wires installed in the hole of the object to be fixed and an optical fiber provided along the strand is covered with a PC steel stranded wire including the edge of the hole. It is a fixing structure that is fixed to the fixing surface.
A nut supported by the edge of the hole on the surface to be fixed,
The inner peripheral surface is crimped to the strand to hold the strand, and the outer peripheral surface is provided with a strand holding portion into which the nut is screwed.
The strand holding portion is provided with an optical fiber insertion passage through which the optical fiber peeled from the PC steel stranded wire with an optical fiber is inserted in a portion other than the inner peripheral surface of the strand holding portion.
The strand holding portion has a fixing structure including an inner sleeve crimped to the strand and an outer sleeve arranged around the inner sleeve and screwed into the nut. An outer sleeve groove extending along the axial direction of the outer sleeve is provided on at least one of the inner peripheral surface and the outer peripheral surface of the outer sleeve.
The fixing structure according to claim 2, wherein the optical fiber insertion passage is the outer sleeve groove. The base of the outer sleeve is provided with a through hole extending along the axial direction of the outer sleeve.
The fixing structure according to claim 2 or 3, wherein the optical fiber insertion passage is the through hole. The outer sleeve is composed of a plurality of dividing members arranged along the circumferential direction of the outer peripheral surface of the inner sleeve.
The fixing structure according to any one of claims 2 to 4, wherein the optical fiber insertion passage is a gap between the divided members adjacent to each other in the circumferential direction. A first screw portion is formed on the inner peripheral surface of the nut, and a second screw portion screwed to the first screw portion is formed on the outer peripheral surface of the outer sleeve.
The fixing structure according to any one of claims 2 to 5, wherein the optical fiber insertion passage is a gap sandwiched between the first screw portion and the second screw portion. A third screw portion is formed on the inner peripheral surface of the outer sleeve, and a fourth screw portion screwed to the third screw portion is formed on the outer peripheral surface of the inner sleeve.
The fixing structure according to any one of claims 2 to 6, wherein the optical fiber insertion passage is a gap sandwiched between the third screw portion and the fourth screw portion. A PC steel stranded wire with an optical fiber having a strand having one or more PC steel stranded wires installed in the hole of the object to be fixed and an optical fiber provided along the strand is covered with a PC steel stranded wire including the edge of the hole. It is a fixing structure that is fixed to the fixing surface.
A nut supported by the edge of the hole on the surface to be fixed,
The inner peripheral surface is crimped to the strand to hold the strand, and the outer peripheral surface is provided with a strand holding portion into which the nut is screwed.
The strand holding portion is provided with an optical fiber insertion passage through which the optical fiber peeled from the PC steel stranded wire with an optical fiber is inserted in a portion other than the inner peripheral surface of the strand holding portion .
The strand holder comprises a sleeve that is crimped to the strand and screwed into the nut.
A first screw portion is formed on the inner peripheral surface of the nut, and a second screw portion screwed to the first screw portion is formed on the outer peripheral surface of the sleeve.
The optical fiber insertion passage has a fixing structure, which is a gap sandwiched between the first screw portion and the second screw portion . A PC steel stranded wire with an optical fiber having a strand having one or more PC steel stranded wires installed in the hole of the object to be fixed and an optical fiber provided along the strand is covered with a PC steel stranded wire including the edge of the hole. It is a fixing method to fix on the fixing surface.
A step of providing a strand holding portion in which the inner peripheral surface is crimped to the strand to hold the strand, and
A step of screwing a nut supported by the edge of the hole on the surface to be fixed to the outer peripheral surface of the strand holding portion,
A step of providing an optical fiber insertion passage through which the optical fiber peeled from the PC steel stranded wire with an optical fiber is inserted is provided in a portion of the strand holding portion other than the inner peripheral surface of the strand holding portion.
The strand holder comprises a sleeve that is crimped to the strand and screwed into the nut.
A fixing method in which a sleeve groove is provided on the outer peripheral surface of the sleeve as the optical fiber insertion passage in the step of providing the optical fiber insertion passage . A PC steel stranded wire with an optical fiber having a strand having one or more PC steel stranded wires installed in the hole of the object to be fixed and an optical fiber provided along the strand is covered with a PC steel stranded wire including the edge of the hole. It is a fixing method to fix on the fixing surface.
A step of providing a strand holding portion in which the inner peripheral surface is crimped to the strand to hold the strand, and
A step of screwing a nut supported by the edge of the hole on the surface to be fixed to the outer peripheral surface of the strand holding portion,
A step of providing an optical fiber insertion passage through which the optical fiber peeled from the PC steel stranded wire with an optical fiber is inserted is provided in a portion of the strand holding portion other than the inner peripheral surface of the strand holding portion.
A fixing method, wherein the strand holding portion includes an inner sleeve that is crimped to the strand and an outer sleeve that is arranged around the inner sleeve and screwed into the nut. A PC steel stranded wire with an optical fiber having a strand having one or more PC steel stranded wires installed in the hole of the object to be fixed and an optical fiber provided along the strand is covered with a PC steel stranded wire including the edge of the hole. It is a fixing method to fix on the fixing surface.
A step of providing a strand holding portion in which the inner peripheral surface is crimped to the strand to hold the strand, and
A step of screwing a nut supported by the edge of the hole on the surface to be fixed to the outer peripheral surface of the strand holding portion,
A step of providing an optical fiber insertion passage through which the optical fiber peeled from the PC steel stranded wire with an optical fiber is inserted is provided in a portion of the strand holding portion other than the inner peripheral surface of the strand holding portion.
The strand holder comprises a sleeve that is crimped to the strand and screwed into the nut.
A first screw portion is formed on the inner peripheral surface of the nut, and a second screw portion screwed to the first screw portion is formed on the outer peripheral surface of the sleeve.
A fixing method in which the optical fiber insertion passage is provided by using the gap sandwiched between the first screw portion and the second screw portion in the step of providing the optical fiber insertion passage .

Images