JPH0753364Y2 - Aerial cable flaw detector - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is designed to mount an electromagnetic flaw detector on a traveling body that travels on an overhead cable such as an overhead power transmission line, an overhead ground wire, or an overhead insulated wire. The present invention relates to an aerial cable flaw detector that inspects for cable damage such as wire breaks and arc traces.

[Prior Art] Conventionally, in order to detect a cable damage state such as a cable surface flaw or an arc mark of an aerial cable, as shown in a schematic view in FIG. 6, it is possible to travel along the aerial cable 1. An aerial cable flaw detector 4 is often used in which an electromagnetic flaw detector equipped with a flaw detection coil 3 of an electromagnetic induction type which is placed close to a cable is mounted on a traveling body 2. As the flaw detection coil, a plurality of small probe-type coils arranged circumferentially around the cable with a space therebetween, a semi-cylindrical cylindrical coil surrounding the cable, and the like are used. The flaw detection coil 3 of the electromagnetic flaw detector in the conventional overhead cable flaw detector 4 of this type is fixedly attached to the machine frame 2a of the traveling body 2 as illustrated.

[Problems to be solved by the invention] By the way, in many cases, plastic rings (snow-diffusing rings) 5 are attached to the aerial cable at intervals of several tens of centimeters as a measure against snow-diffusing. Also, dampers for preventing vibration and twisting are attached at several places within the span. The aerial cable flaw detector 4 needs to get over an obstacle mounted in the above-described span.

On the other hand, the electromagnetic induction type flaw detection method such as eddy current flaw detection (electromagnetic flaw detection method) is based on the principle of detecting a minute change in the self-inductance of the flaw detection coil due to a minute change in the cable surface state due to a cable surface flaw, an arc mark, etc. It is necessary to always keep the relative positional relationship with the flaw detection coil constant.

However, in the conventional aerial cable flaw detector in which the flaw detection coil is fixedly attached to the traveling body, the cable 1 and the flaw detection coil 3 are concentrically arranged as shown in FIG. When moving over an obstacle as shown in FIG. 8, there is a static displacement in the relative position between the cable 1 and the flaw detection coil 3 as shown in FIG. Gap, resulting in
The inductance of the flaw detection coil changes. If the change in the inductance is sufficiently small with respect to the change due to the target cable damage, there will be no problem, but it generally appears as a very large noise signal. Therefore, it is important to always keep the flaw detection coil in the same position (arranged concentrically with the cable) with respect to the cable regardless of the motion of the traveling body.

The present invention has been made in order to solve the above-mentioned conventional drawbacks, and suppresses the vibration of the flaw detection coil when the traveling body passes through obstacles such as snow-drinking rings and damper clamps, and the flaw detection coil is used as a cable. On the other hand, it is intended to prevent the deterioration of the detection performance of the electromagnetic flaw detection device caused by the sway by keeping it at a fixed position.

[Means for Solving the Problems] The present invention for solving the above problems provides an electromagnetic flaw detection apparatus including an electromagnetic induction type flaw detection coil that is placed close to a running body that can run along an overhead cable. In a mounted overhead cable flaw detector, a flaw detection device frame attached to the machine frame of the traveling body, a coil holder attached to the flaw detection coil, which is slidably supported up and down on the flaw detection device frame, and the coil holder. A vertical elastic support mechanism that elastically supports the coil holder in the vertical direction via a spring, and holds the cable so that it is sandwiched by the elastic force in the horizontal direction, but the coil holder is designed to move integrally with the cable in the vertical direction. And a cable holding mechanism provided.

[Operation] When the aerial cable flaw detector with the above configuration passes over an obstacle on the cable and passes, the traveling body sways up and down. However, the coil holder with the flaw detection coil is integrated with the cable in the vertical direction by the cable holding mechanism. Since the vertical movement of the traveling body is absorbed by the vertical elastic support mechanism, the movement of the traveling body is absorbed by the coil holder and Transmission to the flaw detection coil is suppressed, and the positional relationship between the flaw detection coil attached to the coil holder and the cable is kept as constant as possible.

[Embodiment] An embodiment according to the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 5 is a schematic overall view of an overhead cable flaw detector 10 according to an embodiment of the present invention. This aerial cable flaw detector 10 has a structure in which an electromagnetic flaw detector 13 is mounted on a traveling body 12 that can travel along an aerial cable 11. The traveling body 10 has a traveling wheel 15 that is driven by a drive device (not shown) before and after the machine frame 14 of the traveling body 12 and travels on the cable 11, and an auxiliary that elastically sandwiches the cable 11 with the traveling wheel 15. It has a wheel 16 and the electromagnetic flaw detector 13 is attached to the center of the machine frame 14.

Details of the electromagnetic flaw detector 13 will be described with reference to FIGS. A horizontal slide shaft 17 in a direction orthogonal to the cable longitudinal direction is fixed to a machine frame 14 of the traveling body 12, and a pair of left and right flaw detection device frames 18 is slidably provided on the slide shaft 17.

Each flaw detector frame 18 has a vertical slide shaft 19
Is fixed, and the coil holder 20 is attached to the slide shaft 19.
Are slidable up and down. This coil holder
20 is biased upward by a compression spring 21 and downward by a tension spring 22 so that it is held at a position where both springs 21 and 22 are in balance. The vertical slide shaft 19, compression spring 21, tension spring 22 and the like constitute a vertical elastic support mechanism 30 that elastically supports the coil holder 20 in the vertical direction.

At the front and rear parts (left and right parts in FIG. 3) of the left and right flaw detector frames 18, the roller support arms 23 are respectively provided with vertical shafts 24.
Each roller support arm is rotatably mounted around
A guide roller 25 with a groove is rotatably attached to the tip of 23. Each of the roller support arms 23 is urged toward the cable 11 side by a tension spring 26 having one end attached to the roller support arm 23 side and the other end attached to the coil holder 20 side to elastically press the cable 11 from the left and right. Has been done. The roller support arm 23, the guide roller 25,
The tension spring 26 and the like form a cable holding mechanism 27.

A flaw detection coil 29 is attached to the coil holder 20 via an attachment member 28. Example flaw detection coil
Although 29 is a semi-cylindrical cylindrical coil, it is not necessarily limited to this, and a plurality of small probe-type coils arranged around the cable in the circumferential direction and other electromagnetic induction type flaw detection coils should be used. You can

The left and right flaw detection device frames 18 are configured such that the flaw detection coil opening / closing mechanism 31 can widen the left / right spacing.
That is, the link 32 is attached to the upper part of the left and right flaw detector frame 18.
Are horizontally connected, and each link 32 is a center link 33.
The central link 33 is fixed to the lower end of a vertical shaft 34 that is rotatably mounted through the machine frame 14, and the vertical shaft 34 is rotatably biased by a torsion spring 38 in a rotational direction.
An elastic rotational force is applied to the slide shaft 17 by the bevel gear 36, while the left and right flaw detector frames 18 are attached to the slide shaft 17.
Return springs 37 are provided for urging the respective springs outward. The direction of the spring force of the torsion spring 38 applied to the drive shaft 35 is the direction in which the left and right flaw detector frames 18 are biased toward the center via the bevel gear 36, the vertical shaft 34, the center link 33, and the left and right links 32, respectively. And a semi-cracked flaw detection coil
The cable 29 is closed so that it surrounds the cable 11.

Next, the operation will be described.

When the traveling body 12 rides on an obstacle such as a snow-driving ring when the traveling body 12 travels on the cable 11, the traveling body 12 swings mainly up and down. However, since the coil holder 20 is elastically supported in the vertical direction at the position where the compression spring 21 and the tension spring 22 are in balance, the vertical motion of the traveling body 12 is absorbed by the elasticity of both springs 21 and 22, and The vertical movement of the traveling body 12 is suppressed from being transmitted to the holder 20, and the cable 11 of the flaw detection coil 29 is suppressed.
The position with respect to is kept as constant as possible. Therefore, a noise signal is prevented from entering the output of the electromagnetic flaw detector for detecting the damaged state of the cable.

In addition, the roller support arm 24 with the guide roller 25 attached
Since the guide roller 25 is provided in an oblique direction and is pressed against the cable 11 from an oblique direction instead of a right angle direction, the resistance generated when passing through the snow-difficulty ring is reduced.

In addition, a relatively large obstacle larger than the snow-drinking ring, such as a damper clamp, is attached to the cable 11.
If the flaw detection coil cannot pass as it is, drive shaft
35 is rotated by a rotation drive device (not shown) to rotate the vertical shaft 34 via the bevel gear 36, and the center link 33 is rotated to drive the left and right links 32 thereof, and the left and right flaw detection device frames 18 Is expanded to the left and right, so that the semi-cracked flaw detection coil 29 is opened to the left and right, and the damper clamp or the like can be passed therethrough.

If it is not necessary to pass through a large obstacle other than the snow landing ring, such a flaw detection coil opening / closing mechanism may not be provided.

[Effects of the Invention] Since the present invention is configured as described above, it has the following effects.

The coil holder to which the flaw detection coil is attached is made to move integrally with the cable in the vertical direction by the cable holding mechanism, and is supported by the flaw detection device frame via the elastic support mechanism in the vertical direction. When the vehicle travels over an obstacle and moves up and down, the up-and-down motion of the running body is absorbed by the vertical elastic support mechanism, and the up-and-down motion of the running body of the flaw detection coil is suppressed from being transmitted. Therefore, the positional relationship between the flaw detection coil and the cable is kept as constant as possible,
The deterioration of the detection performance of the electromagnetic flaw detector is prevented.

[Brief description of drawings]

FIG. 1 is a front view of an electromagnetic flaw detector of an aerial cable flaw detector according to an embodiment of the present invention, and FIG. 2 is II in FIG.
-II line sectional view, FIG. 3 is a sectional view taken along line III-III in FIG. 1, FIG. 4 is an explanatory view of an opening / closing link portion of a flaw detection coil opening / closing mechanism, and FIG. 5 is a schematic overall view of an overhead cable flaw detector, 6 to 9 show a conventional example, FIG. 6 is a schematic view of an overhead cable flaw detector in a normal traveling state, FIG. 7 is a sectional view taken along line VII-VII in FIG. 6, and FIG. FIG. 9 is a schematic view in the state of climbing up an obstacle, and FIG. 9 is a sectional view taken along line IX-IX in FIG. 10 …… Aerial cable flaw detector, 11 …… Cable, 12 …… Traveling body, 13 …… Electromagnetic flaw detector, 14 …… Machine frame of traveling body, 17…
… Slide shaft, 18 …… Flaw detection device frame, 19 ……
Slide shaft, 20 …… Coil holder, 21 …… Compression spring, 22 …… Tension spring, 23 …… Roller support arm, 24
…… Vertical axis, 25 …… Guide roller, 26 …… Tension spring, 27 …… Cable holding mechanism, 29 …… Detection coil, 30 ……
... Vertical elastic support mechanism.

Claims (1)

[Scope of utility model registration request] 1. An aerial cable flaw detector equipped with an electromagnetic flaw detector equipped with a flaw detection coil of an electromagnetic induction method, which is placed close to the cable, on a running body that can run along an aerial cable. The flaw detection device frame attached to the flaw detection device frame, and the flaw detection device frame slidably supported in the vertical direction,
A coil holder to which the flaw detection coil is attached, an up-and-down elastic support mechanism that elastically supports the coil holder in the up-and-down direction via a spring, and a cable that is held so as to be sandwiched by an elastic force in the left-and-right direction A cable holding mechanism provided on the coil holder so as to move integrally with the cable.