JPH10108330A - Wire leading rod for cable conduct line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a distance for pushing in a wire leading rod. SOLUTION: This wire leading rod 11 is formed by rigidly-connecting a plurality of short rods 12 with rigidity in series so as to be detachable. When the leading-wire rod 11 is led in a conduit line 2 in which a cable 1 has been laid, a front end head 10 is fitted onto the front end of the first short rod 12 and is pushed in, and the other short rods 12 are pushed in sequentially while they are being connected with each other. The rigidity of the leading-wire rod 11 is high, which is formed by rigidly-connecting the short rods 12 with high rigidity, therefore, large pushing effort can be worked, so that the pushing-in distance of the leading-wire rod 11 can be increased. The rigidity of the leading-wire rod 11 is high enough not to cause deflection in a waveform when pushed-in. Consequently, pushing-in force generated when some deflection occurs in the waveform is not dispersed. It is thus possible to act great pushing-in force and attain a long pushing-in distance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire rod used for drawing a sub duct for accommodating an optical fiber into a conduit in which a power cable or the like is already laid.

[0002]

2. Description of the Related Art As shown in FIGS. 7 and 8, for example, when a sub duct (not shown) for storing an optical fiber is laid in an underground pipeline 2 in which a cable 1 such as a power cable is already laid. Generally, an end head 5 is attached to the end of a wire rod 4 wound around a rod reel 3 and this is connected to a conduit 2.
A method is employed in which a subduct is connected to the passing rod 4 and a subduct (not shown) is drawn in. This kind of conventional wire rod 4 has flexibility as evident from being wound around and stored on the rod reel 3, and is generally made of plastic having considerable flexibility.

[0003]

When the wire rod 4 is pushed into the pipe 2, it is necessary to push the wire rod 4 due to frictional resistance with the inner wall of the pipe 2 and the surface of the cable 1. However, there is a problem that the pushing distance of the wire rod 4 is limited due to the increased pushing force and insufficient rigidity of the wire rod 4 against the force. Further, since the rigidity of the wire rod 4 is weak and easily bent, as shown in the plan view of FIG. When it is deflected and pushed into a waveform, the pushing force acting on the wire rod 4 is dispersed. That is, the pushing force in the axial direction of the wire rod 4 does not directly become the pushing force in the pipe length direction of the wire rod 4, but only the component in the pipe length direction of the pushing force in the axial direction is substantially pushed. And the actual pushing force is reduced. As described above, since the pushing force is dispersed due to the bending of the wire rod 4 and the substantial pushing force is reduced, there is also a problem that the pushing distance of the wire rod 4 is limited.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional drawbacks, and has as its object to provide a wire rod for a cable conduit that can increase the pushing distance.

[0005]

According to the present invention, there is provided a connecting rod for a cable conduit, wherein a plurality of rigid rod-like short rods are rigidly connected in series and detachably. I do.

According to a second aspect of the present invention, the short rod has a hollow cylindrical shape penetrating therethrough.

[0007]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIGS. FIG. 1 shows an example of the present invention, in which a cable rod 1 such as an electric power cable is laid in an underground pipe 2, and a lead rod 10 having a head 10 attached thereto is pushed into the pipe 2. FIG. 3 is a view showing a state in which the connecting rod 11 is formed by connecting a plurality of rigid rod-shaped short rods 12 in series, and both ends of each short rod 12 are connected to adjacent short rods 11. It has a connection structure for detachable and rigid connection. Here, the rigidity of the wire rod means a wire rod having no flexibility. For example, the wire rod has a rigidity that cannot be wound around a rod reel having a diameter of 1.7 meters or more. Meaning to have. The rigid connection means that the two connecting rods are not hinged, and that the two connecting rods are connected so as not to be easily bent at the connecting part when a bending moment is applied.

The details of the short rod 12 are shown in FIG.
This short rod 12 has a structure in which a male screw 12a is formed on an outer peripheral surface of one end of a round pipe of, for example, about 1.5 to 2.0 meters, and a female screw 12b is formed on an inner peripheral surface of the other end. The male screw 12a on one short rod 12 side is screwed into the female screw 12b on the other short rod 12 side to be tightly connected. The short rod 12 at the tip is connected to the tip head 10 by screwing the male thread 12a into the female thread 10a formed on the tip head 10.

When the above-mentioned wire rod 11 is pushed into the pipe line 2, the first short rod 12 is connected to the tip head 10, and after pushing in the length of this short rod 12, the next short rod 12 is connected. The operation of connecting and pushing the short rod 12 by the length of the short rod 12 again is repeated, so that the wiring rod 11 is connected. These tasks are performed in manhole 1
It is preferable to carry the short rod 12 into the inside of the housing 5. In this case, the rigidity of each short rod 12 is large and the short rods 12 are rigidly connected to each other.
The rigidity as a whole is large, a large pushing force can be given, and a sufficiently long pushing distance can be realized. In addition, since the rigidity of the entire wire rod 11 is high and it does not easily bend into a waveform, unlike the conventional wire rod 4, the pushing force acting on the wire rod 11 is dispersed and the substantial pushing force is reduced. There is no problem of lowering. Therefore, at this point, the pushing distance of the wire rod 11 can be increased. Also, since each short rod 12 can be shortened to, for example, 1.5 to 2 meters,
There is no particular problem for storing the short rod 12. The connecting rod 11 to which the pipe-shaped short rod 12 is connected penetrates the entirety, and the connecting rod 11 itself can be used as a sub duct for laying an optical cable. In this case, the optical cable is drawn into the hollow portion while leaving the line rod 11 as it is after passing through the conduit 2.

FIG. 4 shows another embodiment of the short rod 22. The short rod 22 has a male pipe 22a attached to one end of a round pipe and a female thread 22a at the other end.
b, and both ends are closed. Similarly to the above, the male screw member 22a on one adjacent short rod 22 is screwed and tightened to the female screw member 22b on the other short rod 22 side. When this short rod 22 is used, the wire rod itself cannot be used as a sub duct.

FIG. 5 shows still another embodiment of the short rod 32. The short rod 32 has a structure in which a male joint 33 having a circumferential groove 33a is attached to one end of a round pipe, and a female joint 34 having a ball 34a engaging with the circumferential groove 33a is attached to the other end. is there. That is, the connecting portion has a one-touch coupling structure. Even when this short rod 32 is used, the line rod itself cannot be used as a sub duct.

The short rods 12, 22, 32 are preferably made of a material having high rigidity and light weight, such as a metal material such as aluminum or FRP (fiber reinforced plastic).
Are used. The cross section of the short rod is not limited to a circular shape, but may be one in which a number of longitudinal grooves 12c are provided on the outer periphery like a short rod 12 'in FIG. In the embodiment, the weight is reduced by using a hollow short rod, but a solid short rod may be used. The wire rod of the present invention is usually used for an existing pipeline, but is not necessarily limited to that case.

[0013]

The wire rod according to the present invention is formed by connecting rigid rod-like short rods in series and detachably to each other.
Since the rigidity of the wire rod is large, a large pushing force can be applied, and a sufficiently long pushing distance can be realized. In addition, since the wire rod has high rigidity and does not easily bend into a waveform, unlike the conventional wire rod, the pushing force acting on the wire rod is dispersed and the actual pushing force is reduced. This does not occur, and the pushing distance of the wire rod can be increased at this point as well. In addition, since the short rods can be bundled and stored, it is not necessary to use a large-diameter rod reel for storing which is necessary for the conventional wire rod. Further, by making the short rod hollow, it is possible to reduce the weight while increasing the rigidity.

[0014] Further, if a hollow cylindrical shape penetrates the communication rod, the communication rod itself can be used, for example, as a sub duct for laying an optical fiber. Is simplified.

[Brief description of the drawings]

FIG. 1 is a diagram showing a state in which a communication rod for a cable conduit according to an embodiment of the present invention is connected to an existing conduit.

FIG. 2 is an enlarged sectional view of a main part of FIG.

FIG. 3 is an enlarged sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view showing another embodiment of the connecting structure of short rods in the present invention.

FIG. 5 is a sectional view showing still another embodiment of the connecting structure of short rods in the present invention.

FIG. 6 is a sectional view showing another embodiment of the short rod according to the present invention.

FIG. 7 is a cross-sectional view of a state in which a conventional cable rod for a cable conduit is connected to an existing conduit.

FIG. 8 is an enlarged sectional view taken along the line AA in FIG. 7;

FIG. 9 is a view for explaining the reason why the push-in distance cannot be increased in the conventional wire-passing operation of the wire rod, and is a plan view in the pipeline of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cable 2 Pipeline 10 Tip head 11 Communication rod 12, 22, 32 Short rod 12a Male screw 12b Female screw 22a Male screw member 22b Female screw member 33 Male joint 34 Female joint

Claims (2)

[Claims] 1. A connecting rod for a cable conduit, comprising a plurality of rigid rod-like short rods connected in series and detachably to be rigidly connected. 2. The line rod according to claim 1, wherein the short rod has a hollow cylindrical shape penetrating therethrough.