JPH057923B2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a method for detecting twisting that occurs in a cable, which is applied when a cable is being laid by drawing it into a conduit such as a trough. It is.

``Prior Art'' FIG. 4 shows a conventional example of a construction method for drawing a cable into an underground conduit.

That is, a reel 4 around which a cable 3 is wound is installed near a manhole 2 provided at one end of a conduit 1 buried underground.
By pulling the traction wire 5 connected to the tip of the cable 3 unwound from the cable 3 with the winch of the work vehicle 7 near the manhole 6 at the other end,
A cable 3 is drawn from one end of the conduit 1 to the other end.

The cable 3 and the traction wire 5 are connected by a method as shown in FIG. 5 or 6. That is, a connecting device called grips is used, which is composed of a stitched portion 8 whose inner diameter is reduced by applying tension, and an eye bolt 9 connected to this stitched portion 8, and a cable is connected to the stitched portion 8. 3 and connecting the traction wire 5 to the eye bolt 9 and pulling it, the stitches are contracted and the cable 3 is gripped, or the eye bolt 9 is attached to the end of the cable 3 using a lead wire or wrapped with tape. The traction wire 5 is similarly connected to the eye bolt 9 by fixing the eye bolt 9 using the method described above.

"Problems to be solved by the invention" By the way, in the above-mentioned installation work, the reel 4
The cable 3 may become twisted while being pulled in due to the effects of winding when it is wound or twisting of the core wire.

Conventionally, as shown in FIG. 7, as a method for detecting twists that have occurred, a straight line 11 is drawn on the surface of the cable 3, and the positions of one end and the other end of this straight line 11 are compared to detect twists. A method is used to detect

However, the above detection method has the following drawbacks.

(a) If the cable has rotated more than one revolution (360°), the angle cannot be determined, and it is difficult to determine whether the cable has rotated in the forward or reverse direction (for example, in the positive direction).
320° or -40°) cannot be determined either.

(b) It is time-consuming to draw a straight line 11 over the entire length of the cable, and it is difficult to draw a straight line without twisting over the entire length of the cable.

(c) Work efficiency is poor because it is essential to visually check the position of the straight line 11 at both ends of the cable.

The present invention was proposed in view of the above circumstances, and
It is an object of the present invention to provide a detection method that can accurately detect twisting of a cable regardless of the rotation direction and rotation angle, and has good workability.

"Means for Solving the Problem" The twist detection method of the present invention involves connecting a traction cable to a connector attached to the tip of the cable, inserting it into a conduit, and pulling the traction cable. In a method for detecting twisting of a cable when drawing the cable into a conduit,
Before pulling the cable into one end of the conduit, a spiral guide member that rotates together with the cable is attached to the connector, and a spiral guide member that rotates together with the cable is attached to the connector, and a spiral guide member that rotates together with the cable is attached to the connector, and a spiral guide member that rotates together with the cable is attached to the connector, and A movable body is provided, and after the tip of the cable is pulled out from the other end of the conduit, the amount of movement of the movable body along the guide member from before the cable is pulled out to after the cable is pulled out is measured. It is characterized by

Further, instead of the spiral guide member, a spiral guide member can also be applied.

"Operation" In the detection method of the present invention, the guide member rotates together with the cable when the cable is twisted, whereas the moving body rotates as the guide member spirals around the axis of the cable. Since the guide member is formed in a shape or a spiral shape, it moves along the length direction of the guide member due to its own weight, and its absolute position does not change. Therefore, as the cable twists, a relative positional change occurs between the guide member and the movable body, and the position of the movable body with respect to the guide member changes from before the cable is pulled into the conduit. It is possible to detect how much the cable is twisted by how far it has moved between the two points.

"Embodiment" Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the figure, parts common to the conventional example are given the same reference numerals to simplify the explanation.

FIG. 1 shows a cable movement detection jig used to carry out the method according to the present invention, and this jig is used, for example, to attach a linear guide member 12 formed into a spiral shape by punching a plate material. , the structure is such that a short tubular moving body 13 that is movable in the length direction of the guide member 12 is provided. Furthermore, an insertion hole 12a for attachment to an eye bolt is formed in the center of the guide member 12. Note that the maximum diameter of the spiral of the guide member 12 is made slightly smaller than the outer diameter of the cable to be attached, and in consideration of the fact that the cable will be twisted multiple times, the number of turns is at least about 3. has been done. Furthermore, the guide member 12 has a plurality of marks 1 indicating the position of the moving body.
4 is formed every 90 degrees of rotation angle.

When trying to detect cable twist using such a movement detection jig, first
As shown in the figure, the insertion hole 12a of the guide member 12
A mounting bolt 9a integrated with the eye bolt 9 is inserted into the cable 3, and the mounting bolt 9a is fixed to the end of the cable 3 (for example, using the connector shown in FIGS. 5 and 6), and then the guide member The movable body 13 is fitted into the movable body 12 and placed at a predetermined position, for example, the position shown by the solid line in FIG. Laying is carried out by pulling as in the example. After the tip of the cable 3 has been pulled out over a predetermined length from the end of the conduit, the amount of twist of the cable 3 can be detected by checking the position of the moving body 13.

That is, the guide member 12 rotates together with the cable 3 when the cable 3 is twisted, whereas the movable body 13 has the guide member 12 spirally formed around the axis of the cable 3. Therefore, it moves along the length direction of the guide member 12 due to its own weight, and is only displaced relative to the guide member 12, but its absolute position does not change. Therefore, before the cable 3 is drawn into the conduit, the movable body 13 is placed, for example, at the position shown by the solid line in FIG. If it is moving, it means that the cable 3 has made one rotation in the clockwise direction in Figure 1, and if it is moving to the position shown by the symbol 13'', it is also said that it has made one rotation in the counterclockwise direction. Become.

Note that since the guide member 12 is provided with a mark 14 for knowing the position of the movable body 13 in more detail, the rotation angle can be accurately detected even when the cable 3 has not rotated an integral number of times. can.

Furthermore, the shape of the guide member is not limited to the one described above, and it goes without saying that the number of turns may be increased or decreased, or the display pitch of the marks may be changed. Furthermore, the shape of the spiral is not limited to the one described above, but may be one that can rotate integrally around the axis of the cable and has a continuous curve, for example, as shown in FIG. As in other embodiments, the helical guide member 1
2A may be applied, and the guide member 12A may be provided so as to be able to rotate together with the cable 3 (attachment bolt 9a).

Furthermore, in the embodiment described above, an eye bolt is used as a connector between the cable and the traction wire, but it goes without saying that other connectors may be used.

"Effects of the Invention" As is clear from the above description, the twist detection method of the present invention provides the following effects.

(i) The rotation angle can be accurately detected even when the cable rotates more than one revolution (360°) or when the cable rotates in either forward or reverse direction.

(ii) The amount of twist can be determined only at one end (outlet side) of the pipe, making it easy to work.

[Brief explanation of drawings]

FIG. 1 is a plan view of a guide member applied to one embodiment of the present invention, FIG. 2 is a perspective view showing the attached state of the guide member, and FIG. 3 is a plan view of another guide member applied to the present invention. A perspective view showing an example, and FIGS. 4 to 6 show conventional examples of cable installation work, FIG. 4 is an explanatory view of the working state, and FIG. 5 is a side view showing an example of the processing state of the cable end. FIG. 6 is a side view showing another example, and FIG. 7 is a perspective view showing a conventional example of a cable torsion measuring method. 3... Cable, 9... Eye bolt (coupling tool),
12... Guide member, 12A... Guide member, 1
2a...Insertion hole, 13...Moving body, 14...Mark.

Claims (1)

[Claims] 1. When a traction cable is connected to a connector attached to the tip of the cable and inserted into the conduit, and the cable is pulled into the conduit by pulling the traction cable, In the method for detecting twisting of a cable, before the cable 3 is drawn into one end of the conduit 1, a spiral guide member 12 that rotates together with the cable is attached to the connector 9 with the axis of the cable as the center, and , a movable body 13 is provided which is movable in the length direction of the wire constituting the guide member, and after the tip of the cable is pulled out from the other end of the conduit, the movement from before to after the cable is pulled out is provided. A cable twist detection method comprising measuring the amount of movement of the movable body along the guide member. 2 Connect a traction cable to a connector attached to the tip of the cable, insert it into the conduit, and pull the traction cable to detect twisting of the cable when pulling the cable into the conduit. In the method, before the cable 3 is drawn into one end of the conduit 1, a spiral guide member 12 that rotates together with the cable is attached to the connector 9 around the axis of the cable, and the guide member is configured. A movable body 13 is provided that is movable in the length direction of the wire, and after the tip of the cable is pulled out from the other end of the conduit, the movable body 13 is guided by the movable body from before to after the cable is pulled out. A cable twist detection method characterized by measuring the amount of movement along a member.