JP4051312B2 - Fiber optic cable gripping device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gripping device for gripping an optical fiber cable used as a strain sensor for measuring deformation of a structure such as a tunnel.
[0002]
[Prior art]
For example, in structures such as tunnels, cracks and other deformations occur on the wall surface due to secular change, etc., and there is a danger of collapse if left untreated. For this reason, optical fiber cables are used as strain sensors. A monitoring system is generally known that detects a change in a tunnel using an optical fiber cable and sequentially monitors the state of the tunnel.
[0003]
In other words, this monitoring system is constructed by holding a series of optical fiber cables along the wall of the tunnel for each fixed span, transmitting a light pulse to the optical fiber of this cable, and the Brillouin scattered light in the optical fiber by the light pulse. This is a system that detects the deformation of the tunnel wall surface by detecting the strain due to the tension change of the cable in each span.
[0004]
Conventional gripping jig for gripping the optical fiber cable used for this type of application, includes a bracket attached to the wall of the tunnel, the gripping member attached to the brackets, bolt-like this gripping member has a screw on the outer periphery It is divided into two in the axial direction, and an optical fiber cable is sandwiched between the divisions. The gripping member slidably penetrates the standing wall of the bracket. In this state, nuts are screwed to both sides of the gripping member, and the gripping member is fastened to the standing wall by tightening these nuts.
[0005]
A large number of such jigs are attached for each predetermined span of the wall surface of the tunnel, and the optical fiber cable is installed so as to extend along the tunnel via each jig.
[0006]
Then, when a crack or other deformation occurs in the tunnel wall in a certain span, the strain of the optical fiber cable in that section changes accordingly, and the strain is measured by the strain measuring device of the monitoring system. And the deformation is detected.
[0007]
[Problems to be solved by the invention]
The optical fiber cable needs to be adjusted in advance so that the tension in each span becomes a predetermined value. This adjustment is performed by loosening the nut and moving the gripping member in the axial direction.
[0008]
Here, in order to adjust the tension of a section of a certain span, when the gripping member of the jig in that section is moved in the axial direction, the tension of the optical fiber cable in the next section changes due to the movement. If the tension of one span is changed, the effect spreads to the whole of other spans. Therefore, it is necessary to adjust the tension sequentially over each span. Time is required and efficiency decreases.
[0009]
When attaching the optical fiber cable to the jig, first remove the nut from the gripping member, then remove the gripping member from the bracket, insert the optical fiber cable between the gripping member divisions, and then sandwich the gripping member again. Is inserted into the upright wall of the bracket, and a nut is screwed and tightened to the gripping member, which requires a cumbersome and time-consuming work, and the work efficiency is lowered.
[0010]
By the way, as the optical fiber cable used for this kind of application, a variety of sizes are used. In the conventional jig, it is difficult to cope with the optical fiber cable of each size, and individual jigs corresponding to the respective sizes are required, which causes a problem of high cost.
[0011]
The present invention has been made paying attention to such points, and the purpose of the present invention is to adjust the tension of one span section of an optical fiber cable, and to affect the other span section. Therefore, it is possible to easily and efficiently adjust the tension, and to easily and efficiently attach the optical fiber cable, and to provide a general-purpose optical fiber cable gripping device that can be used for various sizes of optical fiber cables. There is.
[0012]
[Means for Solving the Problems]
In order to achieve such an object, the present invention is a gripping device for gripping an optical fiber cable used as a strain sensor for measuring deformation of a structure such as a tunnel , and each other for each predetermined span of the optical fiber cable. A plurality of gripping jigs mounted in parallel are provided, and each of the gripping jigs individually includes a base, a pair of gripping bases slidably provided on the base in the left-right direction, and the gripping bases individually. A sliding mechanism for sliding, a pinching portion provided on each gripping base, a pinching member that can be inserted into each pinching portion, and a pinching portion that holds the pinching member when the pinching member is inserted into each pinching portion Each clamping member is composed of a pair of clamping pieces, and an optical fiber cable is sandwiched between the pair of clamping pieces and attached. Each pinching member in a state in which挾着fiber cable was inserted the into nip of each gripping stage, holding the optical fiber cable fastened by the clamp mechanism, one of the one gripping tool arranged next to each other It is possible to adjust the tension of the optical fiber cable in the span between the gripping jigs arranged next to each other by sliding the gripping base by the slide mechanism.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, a plurality of jigs 10 are attached in parallel to each other in a predetermined span L (2 to 5 m) on the wall surface of the tunnel. As shown in FIGS. 1 to 5, each jig 10 has a base 11, a rail portion 12 is provided on one side of the base 11, and a pair of gripping bases 13 a and 13 b are provided on the rail portion 12. They are fitted parallel to each other so as to be slidable in the left-right direction.
[0014]
A partition wall 15 is integrally provided at an intermediate portion of the rail portion 12 so as to be disposed between the one gripping base 13a and the other gripping base 13b. The bolts 16 constituting the slide mechanism penetrate through the gripping bases 13a and 13b, the tip ends of the bolts 16 are rotatably connected to the partition wall 15, and the bolts 16 are rotated to rotate the gripping bases. 13a and 13b can be individually slid along the rail portion 12 in the left-right direction. Reference numeral 17 denotes a lock nut screwed to each bolt 16. The lock nut 17 can fix the gripping bases 13 a and 13 b at predetermined positions.
[0015]
A fixed wall 20 is integrally formed on the upper surfaces of the gripping bases 13a and 13b, and a movable wall 21 is mounted so as to face the fixed wall 20. The movable wall 21 is provided so as to be movable in a direction in which it is in contact with and away from the fixed wall 20.
[0016]
A sandwiching member 24 including a pair of sandwiching pieces 24a and 24b is inserted into the sandwiching portions 22 of the gripping bases 13a and 13b. And the optical fiber cable C is inserted | pinched between the clamping pieces 24a and 24b in each clamping member 24 inserted in the clamping part 22 of each holding stand 13a and 13b.
[0017]
Clamp bodies 26 constituting a clamp mechanism are provided on the upper portions of the gripping bases 13a and 13b, respectively. The clamp body 26 is substantially U-shaped, one end of which is rotatably supported on the side of the fixed wall 20 via a pin 27, and the eccentric shaft 28 is connected to the other end via a pin 29. A knob 30 is provided on the eccentric shaft 28.
[0018]
The clamp body 26 rotates about the pin 27 so that the eccentric shaft 28 is detachably engaged with the back surface of the movable wall 21, and the eccentric shaft 28 is gripped 30 under the engaged state. , The movable wall 21 is pressed toward the fixed wall 20, and the pressing member 24 is firmly attached between the movable wall 21 and the fixed wall 20 by this pressing. . As shown in FIG. 4, a concave portion 33 having an arcuate cross section corresponding to the eccentric shaft 28 is formed on the back surface of the movable wall 21, and the eccentric shaft 28 is fitted into the concave portion 33 to prevent the separation. .
[0019]
Further, by rotating the eccentric shaft 28 in the reverse direction via the knob 30, it is possible to release the pressure on the movable wall 21 and rotate the clamp body 26 upward to release the restraint of the movable wall 21. It is like that.
[0020]
As shown in FIG. 6, the optical fiber cable C is formed by coating a plurality of optical fibers F with a covering material M made of synthetic resin, and the cross section is flat. A shallow fitting groove 35 corresponding to the shape of the side surface of the optical fiber cable C is formed on the inner surface of each of the sandwiching pieces 24a and 24b constituting the sandwiching member 24 along the longitudinal direction thereof.
[0021]
Further, on both sides of the fitting groove 35 in one sandwiching piece 24a, fine concave and convex processing 36 is applied to contact with both sides of the optical fiber cable C and bite into both sides. Further, a positioning recess 38 that can be fitted to the movable wall 21 is formed on the back surface of one of the sandwiching pieces 24a.
[0022]
Further, positioning pins 40 are attached to the four corners of the inner surface of one sandwiching piece 24a, and pin holes 41 corresponding to the respective pins 40 are formed in the four corners of the inner surface of the other sandwiching piece 24b. Has been.
[0023]
Next, a procedure for attaching the optical fiber cable C to the jig 10 will be described. First, the optical fiber cable C is disposed between the inner surfaces of the pair of sandwiching pieces 24a and 24b, fitted into the fitting groove 35, and the optical fiber cable C is sandwiched between the sandwiching pieces 24a and 24b. At this time, the pin 40 of one pinching piece 24a is inserted into the pin hole 41 of the other pinching piece 24b. As a result, the sandwiching pieces 24a and 24b are accurately coupled to face each other.
[0024]
Next, both the sandwiching pieces 24a and 24b are inserted into the sandwiching part 22 between the fixed wall 20 and the movable wall 21 in the gripping base 13a as shown in FIG. At this time, the clamp body 26 is opened, and the movable wall 21 is moved in a direction away from the fixed wall 20 to widen the sandwiching portion 22.
[0025]
After that, the movable wall 21 is moved in the direction approaching the fixed wall 20 as indicated by a chain line, and the movable wall 21 is fitted into the recess 38 on the back surface of the sandwiching piece 24a, so that both sandwiching pieces 24a and 24b are moved. Position.
[0026]
Next, the clamp body 26 is rotated counterclockwise in FIG. 4, and the eccentric shaft 28 is engaged with the recess 33 on the back surface of the sandwiching piece 24 a, and the eccentric shaft 28 is rotated through the knob 30. The movable wall 21 is tightened. As a result, the sandwiching pieces 24a and 24b are firmly attached by the movable wall 21 and the fixed wall 20 as shown in FIG. 3, and the optical fiber cable C is stably fixed to the gripping base 13a.
[0027]
Further, the optical fiber cable C is attached and fixed to the other gripping base 13b in the same procedure. In this manner, the optical fiber cable C is sequentially attached to the jigs 10 arranged in the tunnel, and the optical fiber cable C is installed along the tunnel.
[0028]
On the other hand, after adjusting the optical fiber cable C, when adjusting the tension of the optical fiber cable C in the span L section shown in FIG. Slide along 12.
[0029]
That is, the locking nut 17 is loosened, the bolt 16 is rotated, and the grip base 13 a is slid along the rail portion 12 by the rotation of the bolt 16. By this slide, the tension of the optical fiber cable C in the span L section changes. Therefore, by adjusting the slide amount, the tension of the optical fiber cable C in the span L section can be adjusted to a desired tension.
[0030]
At this time, the movement of the gripping table 13a by sliding is only transmitted to the optical fiber cable C in the span L section, and does not reach the optical fiber cable C in the span section on both sides. The tension can be adjusted independently and efficiently.
[0031]
The optical fiber cable C is gripped by a pair of sandwiching pieces 24a and 24b, but the side of the fitting groove 35 in one of the sandwiching pieces 24a is provided with uneven processing 36, so that the optical fiber cable C is strong. Therefore, it is possible to maintain a stable gripping state without being displaced by tension.
[0032]
The concave / convex processing 36 is provided on the side of the fitting groove 35. For this reason, the concave / convex processing 36 is crimped to the side of the optical fiber cable C, that is, the portion avoiding the insertion portion of the optical fiber F. The inconvenience that the optical fiber F is damaged by the pressure can be prevented.
[0033]
When the optical fiber cable C is attached to the jig 10, as described above, the sandwiching pieces 24a and 24b sandwiching the optical fiber cable C are inserted into the sandwiching portions 22 of the gripping bases 13a and 13b and tightened with the clamp body 26. For this reason, the mounting operation can be easily and efficiently performed.
[0034]
On the other hand, when the size of the optical fiber cable C is changed, the jig 10 can be used as it is simply by replacing only the sandwiching pieces 24a and 24b of the sandwiching member 24 corresponding to the optical fiber cable C. .
[0035]
That is, the shape of the fitting groove 35 on the inner surface of the sandwiching pieces 24a and 24b merely forms the sandwiching pieces 24a and 24b corresponding to the shape of the optical fiber cable C, and the configuration of the other parts of the jig 10 is not changed. The jig 10 can be used for general purposes.
[0036]
In the above embodiment, an example in which an optical fiber cable as a strain sensor is installed in a tunnel is used. However, it goes without saying that the present invention can be similarly applied to other structures.
[0037]
【The invention's effect】
As described above, according to the present invention, adjusting the tension in one span section of the optical fiber cable does not affect the other span section, so that the tension adjustment work can be performed easily and efficiently. In addition, the optical fiber cable can be easily and efficiently attached, and can be used in general for optical fiber cables of different sizes.
[Brief description of the drawings]
FIG. 1 is a front view showing an installed state of an optical fiber cable held by a jig according to an embodiment of the present invention.
FIG. 2 is a plan view of the jig.
FIG. 3 is a side view of the jig.
FIG. 4 is a side view showing a state when an optical fiber cable is attached to the jig.
FIG. 5 is a plan view showing a state where a clamp mechanism of the jig is opened.
FIG. 6 is a perspective view of a pinching member that holds an optical fiber cable.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Jig, 11 ... Base, 12 ... Rail part, 13a, 13b ... Grasp stand, 16 ... Bolt (slide mechanism), 20 ... Fixed wall, 21 ... Movable wall, 22 ... Clamping part, 24 ... Clamping member, 24a , 24b ... sandwiching piece, 26 ... clamp body (clamp mechanism), 35 ... fitting groove, 36 ... uneven processing.

Claims (3)

A gripping device for gripping an optical fiber cable used as a strain sensor for measuring deformation of a structure such as a tunnel, and comprising a plurality of gripping jigs attached in parallel to each other for each predetermined span of the optical fiber cable ,
Each gripping jig is provided on a base, a pair of gripping bases slidably provided on the base in the left-right direction, a slide mechanism for individually sliding the gripping bases, and the gripping bases. Each sandwiching member comprising: a sandwiching portion; a sandwiching member that can be inserted into each sandwiching portion; and a clamp mechanism that fastens the sandwiching member to the sandwiching portion when the sandwiching member is inserted into each sandwiching portion. Each of which is composed of a pair of sandwiching pieces, sandwiching the optical fiber cable with the pair of sandwiching pieces, and inserting each of the sandwiching members with the optical fiber cable attached thereto into the sandwiching part of each gripping base, Fasten with the clamp mechanism to grip the optical fiber cable,
It is possible to adjust the tension of the optical fiber cable in the span between the adjacent holding jigs by sliding one holding table of the one holding jig arranged adjacent to each other by the slide mechanism. It is by fiber optic cable gripping device, characterized in that are. 2. An optical fiber cable gripping device according to claim 1, wherein an inner surface of at least one of the pair of sandwiching pieces in the sandwiching member is provided with a concavo-convex process for crimping to the optical fiber cable. . The sandwiching portion is composed of a fixed wall and a movable wall provided so as to be movable toward and away from the fixed wall, and the sandwiching member is inserted between the fixed wall and the movable wall. The optical fiber cable gripping device according to claim 1.

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