JPH0755019B2 - Inspection device for cable entry hole - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a cable entry hole inspection device.

[Conventional technology and its problems]

Conventionally, when inspecting pipelines for underground power transmission lines, underground distribution lines, communication cables, etc., if there are holes in the pipeline, use the holes to perform "test stick threading" or "TV camera threading". And so on.

However, if there are no holes, there is no appropriate inspection method, and the development of an effective inspection method has been desired.

Then, a method of inspecting the cable entry hole by inserting an image guide having an objective lens attached to the tip into the cable entry hole which is the above-mentioned conduit is conceivable.
There is a possibility that the image guide may fall into a minute portion of the gap formed between the inner peripheral surface of the cable entry hole and the outer peripheral surface of the cable, and may not be able to be inserted or removed.

Therefore, it is an object of the present invention to solve the above-mentioned conventional problems and to provide a cable entry hole inspection device capable of inspecting the cable entry hole simply and quickly.

[Means for solving problems]

The inspection device for the cable entry hole of the present invention forms an insert by inserting an image guide having an objective lens attached to the insertion guide tube into the insert guide tube, and determines the outer diameter of the head portion of the insert to the cable. The size is 40% or more of the size obtained by subtracting the outer diameter of the cable in the cable entry hole from the hole diameter of the entry hole.

[Action]

If configured as described above, the image guide is protected by the insertion guide tube, and the maximum gap size of the gap formed between the inner peripheral surface of the cable entry hole and the outer peripheral surface of the cable is
The diameter of the cable entry hole is the outside diameter of the cable inside the cable entry hole, and the outer diameter of the head of the insert is 40% or more of the minus size. When it is inserted into the wire entry hole, the head portion of the insert body is located in the gap portion near the maximum gap size, and does not fall into the minute portion of the gap portion.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to the drawings illustrating examples.

In FIG. 1, reference numeral 1 denotes an insert body to be inserted into the cable entry hole 2, which is an insertion guide tube 3 and the insertion guide tube 3
And an image guide 4 inserted into the. And
The base end of the insert 1 is connected to an eyepiece having an eyepiece, and the objective lens 5 is attached to the tip of the image guide 4.
Is attached to form the objective unit 6.

The image guide 4 is composed of a glass portion including a plurality of pixels and a coating layer that covers the glass portion,
The pixel is composed of a core and a clad. Then, the image of the observed portion is made incident on the image guide through the objective lens 5 and transmitted to the eyepiece portion, and the observed portion is observed through the eyepiece lens of the eyepiece portion.

Further, the insertion guide tube 3 is made of a flexible synthetic resin having no seam, for example, crosslinked polyethylene, and has a base end portion,
It has an injection port for allowing a fluid such as fresh water to flow into the insertion guide tube 3, and causes the fluid from the injection port to flow out from the tip opening 7.

That is, when the cable entry hole 2 is filled with suspended water or the like, a fluid such as fresh water is caused to flow into the insertion guide tube 3 and the fluid is caused to flow out from the distal end opening portion 7 of the insert body 1, thereby The suspended water in the wire entry hole 2 can be washed away, and the objective portion 6 can be washed to make the image of the observed portion of the cable entry hole 2 by the image guide always clear.

Thus, the outer diameter dimension A of the head portion 8 of the insert 1 described above
(In this case, the outer diameter dimension of the insertion guide tube 3) is 40% or more of the dimension D obtained by subtracting the outer diameter dimension C of the cable 9 in the cable entry hole 2 from the hole diameter dimension B of the cable entry hole 2. There is.

Therefore, as shown in FIG. 2, the inner peripheral surface of the cable entry hole 2
2a and the outer peripheral surface 9a of the cable 9, the maximum clearance dimension of the clearance section 10 having a crescent cross-section is the above-mentioned subtracted dimension D, and the head section 8 of the insert 1 is close to the maximum clearance dimension. It will be located in the gap 10. That is, the head portion 8
Does not fall into the minute portion 10a of the gap 10 from the position indicated by the phantom line, so that the insertion body 1 can be inserted into and pulled out from the cable entry hole 2 smoothly, and
The image guide 4 can secure a wide field of view.

When the cable entry hole 2 is curved in an L shape or an S shape, the cable 9 may partially come near the center of the cable entry hole 2 as shown in FIG.
In such places of use, the outer diameter dimension A is
It is desirable to set it near 40% of -C. Further, at the portion where the cable entry hole 2 is curved, the cable 9 is eccentric toward the side surface of the cable entry hole 2 as shown in FIG. Also in this case, the head portion 8 of the insert 1 has the gap 10
Does not fall into the minute portion 10a.

In the above-described embodiment, since the insertion guide tube 3 is formed of a flexible synthetic resin (cross-linked polyethylene) having no seam, it can be easily inserted into and pulled out from the wire entry hole 1, and the image guide 4 can be used. Is also easy to insert into the guide tube 3.
Further, during insertion or withdrawal, a part of the guide tube 3 does not fall off, and a part of the dropped guide tube 3 does not remain inside the wire entry hole 1.

In order to inspect the cable entry hole 2 with this inspection device, the insert 1 is inserted into the cable entry hole 2, and when the entry hole 2 is filled with suspension water, it is replaced with fresh water. Then, the suspended water is washed away, and the inside of the wire entry hole 2 is observed and inspected by the image guide.

Further, in order to measure the step size E of the cable entry hole 2 having a step as shown in FIG. 3 with this inspection device, the insertion guide tube 3 and the objective section 6 of the image guide 4 are set to the step section 11. And pulling back only the image guide 4 gradually, and when pulling back the image guide 4 is stopped when the inner peripheral edge 12 of the distal end opening of the insertion guide tube 3 is reflected in the image from the image guide 4, As shown in FIG. 4, the inner peripheral edge 12 of the distal end opening, the inner peripheral surface 13 of the insertion guide tube 3, and the step edge 11a of the step portion 11 are shown in the image, and the step dimension E is obtained. be able to. That is, the inner diameter dimension F and the wall thickness dimension G of the insertion guide tube 3 are known, and
Since the viewing angle of the image guide 4 is known, the ratio between the inner diameter dimension Fa of the insertion guide tube 3 on the image and the dimension Ha on the image of the dimension H obtained by subtracting the wall thickness dimension G from the step dimension E is obtained. Then, if the proportional calculation is performed, the actual dimension H can be obtained. Then, if the thickness dimension G is added to this dimension H, the actual step dimension E can be obtained.

When the cable 9 has a small diameter, a tip attachment 14 as shown in FIGS. 5 to 8 is attached to the tip of the insertion guide tube 3 so that the head portion 8 of the insert 1 has a large diameter. As described above, the outer diameter dimension A of the head portion 8 is set to 40% or more of the dimension D obtained by subtracting the outer diameter dimension C of the cable 9 of the cable entry hole 2 from the hole dimension dimension B of the cable entry hole 2, and FIG. As shown in, the head portion 8 is set so as not to fall into the minute portion 10a of the gap portion 10 from the position indicated by the imaginary line.

Specifically, the attachment 14 shown in FIG. 5 has a structure in which a pair of halves are joined together, and is made of a mold material such as plastic which is fitted to the insertion guide tube 3 and has an outer peripheral surface which is streamlined. , Both ends are attached to the insertion guide tube 3 by attaching members 15 and 15 such as an adhesive tape and a stopper band, and the insertion guide tube 3 and the attachment 14 are integrated. Reference numeral 16 is a pawl member that is fixed to the outer peripheral surface 17 of the insertion guide tube 3 along the circumferential direction, and is fitted into a concave peripheral groove 19 provided in the inner peripheral surface 18 of the attachment 14 to lengthen the attachment 14. Prevents deviation in direction.

Further, the attachment 14 shown in FIG. 6 has a recess 20 formed in the outer peripheral surface 17 of the insertion guide tube 3, and a fastener 21 such as a screw attached to the attachment 14 is fitted into the recess 20.
The attachment 14 and the insertion guide tube 3 are integrated.

Next, the attachment 14 shown in FIG. 7 is an attachment forming member 22 made of elastically deformable wire or leaf spring material.
Are formed by arranging them at equal pitches on the circumference, and the outer diameter of the attachment 14 can be reduced. That is, the attachment forming members 22 are radially arranged when viewed from the distal end surface side of the insertion guide tube 3, and each of the attachment forming members 22 has its tip bent toward the base end side of the insertion guide tube 3. , A contact portion 23 is formed, the contact portion 23 is attached to the insertion guide tube 3 by a mounting member 24 such as a tightening band, and the rear end portion of the attachment forming material 22 is slidable in the arrow direction. Is attached to the insertion guide tube 3 via a mounting member 24. Therefore, this attachment forming material
If 22 is pressed as indicated by arrow X, it deforms as shown by the phantom line, and the outer diameter dimension of this attachment 14 can be reduced. That is, it is possible to deal with various cables 9 having different outer diameter dimensions C.

In addition, the attachment 14 shown in FIG. 8 has a threaded portion 25 formed on the outer peripheral surface 17 of the insertion guide tube 3, and a screw hole 26 formed in the attachment 14 is screwed into the threaded portion 25 to attach the attachment 14 to the attachment 14. And the insertion guide tube 3 are integrated.

Although the attachments 14 other than those shown in FIG. 7 have the same outer diameter, they can be easily attached and detached as described above. It can correspond to various cables 9.

Next, FIG. 10 shows another embodiment of the insert 1. In this case, the insertion guide tube 3 is provided with a metal tip tube portion 27 and a tip end via a connecting material 28 made of metal or synthetic resin. The image guide 4 is composed of a guide tube main body 29 made of a flexible synthetic resin such as flexible cross-linked polyethylene having no synthetic resin seam, which is connected to the tubular portion 27. The image guide 4 has a plurality of light guides (not shown). ), The optical fiber main body 31 is formed by being inserted into the cladding tube 30, and the optical fiber main body 31 is fixed to the insertion guide tube 3.

Then, the cylindrical window portion 32 is formed so as to project from the tip end surface of the optical fiber main body 31 (that is, the tip end surface of the objective portion 6) by a predetermined dimension L. The predetermined dimension L is a dimension such that at least the tip opening edge 34 of the window portion 32 is projected on the image by the image guide. Of course, in this case as well, the tip opening 33 of the window 32 is formed.
A flow path is formed in the insert 1 so that a fluid such as fresh water can flow out from the insert. Further, in this case, the distal end tube portion 27 is detachably attached to the connecting member 28 via an attachment tool such as a screw. The proximal end side of the distal end cylinder portion 27 is used as a screw hole, and a screw portion into which the screw hole is screwed is formed at the distal end portion of the connecting member 28, and the screw hole of the distal end cylinder portion 27 is screwed into The distal end cylinder portion 27 can be detachably attached to the connecting member 28 by screwing it to the portion.

Therefore, in this case, the outer diameter dimension A of the head portion 8 of the insert 1 (that is, the outer diameter dimension of the insertion guide tube 3) is also the same as the above-described embodiment, as shown in FIG. Of the dimension D obtained by subtracting the outer diameter dimension C of the cable 9 from the hole diameter dimension B of
40% or more, the minute portion of the gap 10 as in the above embodiment
It is designed not to get depressed in 10a.

That is, when inspecting the cable entry hole 2 with the inspection device configured as described above, the observed portion is illuminated from the base end side through the illumination light and the light guide, and the covering observation portion is set on the image guide 4. In this case, when measuring the step size of the cable entry hole 2 in which a step as shown in FIG.
Since 34 is projected, the image guide 4 is in a retracted state, and it is extremely easy to measure the step size A.

Also in the embodiment, if a tip attachment 14 as shown in FIGS. 5 to 8 is attached to the tip tube portion 27,
As shown in FIG. 12, even when the cable 9 has a small diameter, the head portion 8 of the insert 1 does not fall into the minute portion 10a of the gap portion 10.

Note that the present invention is not limited to the above-described embodiments, and design changes can be freely made without departing from the gist of the present invention. For example, in the embodiment shown in FIG. It is also preferable to provide a guide. Further, in both of the embodiments shown in FIGS. 1 and 10, when the cable entry hole 2 is not filled with suspended water and dust or dust is present, the inside of the entry hole 2 is If the inflowing fluid is air, the dust, dust, etc. can be blown out from the vicinity of the objective section 6, and the image of the image guide becomes clear. Of course, if the cable entry hole 2 is not filled with suspended water, or if there is no dust or dust, it is also possible to prevent the fluid from flowing into the entry hole.

〔The invention's effect〕

In the cable entry hole inspection device of the present invention, the image guide 4 is protected by the insertion guide tube 3, so that when the insertion body 1 is inserted into the cable entry hole 2, the image guide 4 is not damaged. Further, since the head portion 8 of the insert body 1 does not fall into the minute portion 10a of the gap portion 10, the inserting body 1 can be inserted into or pulled out from the cable entry hole 2 at all times, and the image guide 4 The field of view is always wide. Therefore, if this inspection device is used, the cable entry hole 2 can be inspected easily and quickly.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part showing an embodiment of the present invention, FIG. 2 is a lateral sectional view, FIG. 3 is an explanatory view for explaining a method for measuring a step size of a cable entry hole, and FIG. 4 is an image. FIG. 5, FIG. 6, FIG. 7, FIG. 7, and FIG. 8 are enlarged cross-sectional views of the tip attachment attached to the tip of the insertion guide tube, and FIG. 9 is attached with the tip attachment. 10 is a horizontal cross-sectional view of the other embodiment of the present invention, FIG. 11 is a vertical cross-sectional view of an essential portion of another embodiment, FIG. 11 is a cross-sectional view of the insert body inserted into the cable entry hole, and FIG. 12 is the tip attachment. Fig. 13 and Fig. 14 are cross-sectional views showing a state in which the insert attached with is inserted into the cable entry hole, and Figs. 13 and 14 are cross-sectional views showing the case where the insert is in another position of the cable entry hole. . 1 ... Insert, 2 ... Cable entry hole, 3 ... Insertion guide tube, 4 ... Image guide, 5 ... Objective lens, 8 ...
… Head, 9… Cable, A, C… Outer diameter dimension, B…
… Pore size, D… Subtracted size.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masami Ishihii 1-12-17 Umeda, Kita-ku, Osaka City, Osaka Prefecture (Umeda Building) Inside the Osaka office of Mitsubishi Cable Industries, Ltd. (72) Inventor Masayuki Hamada Osaka City, Osaka Prefecture 3-17 Chifune, Nishiyodogawa-ku, Ryosei Densetsu Co., Ltd. (72) Inventor Katsushi Kusunoki 3-7-1, Chifune, Nishiyodogawa-ku, Osaka, Osaka

Claims (1)

[Claims] 1. An insert guide tube is inserted with an image guide having an objective lens attached to the tip thereof to form an insert body, and the outer diameter of the head portion of the insert body is calculated from the hole diameter of the cable entry hole. An inspection device for a cable entry hole, which is 40% or more of a size obtained by subtracting the outer diameter dimension of the cable in the cable entry hole.