JP3135095B2 - Bamboo thread head to power cable conduit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bamboo threading head which is attached to the end of a bamboo threading rod when bamboo threading is performed on a conduit in which a power cable is already laid.

[0002]

2. Description of the Related Art Conventionally, a bamboo rod 1 to which a hook 2 for pulling in a wire is attached as shown in FIG. Is being done. When this bamboo rod 1 is pushed into the conduit 4 containing the triplex cable 3, the bamboo rod 1 is wound along the twist of the triplex cable 3 as shown in FIG. It is difficult to do bamboo shoots.

[0003]

As described above, when a conventional bamboo rod is used, when a triplex cable is laid in a pipeline, the bamboo rod is connected to the triplex cable along the twist. Because it is wrapped around, bamboo threading becomes extremely difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a novel head for a power cable pipe which can be easily threaded by making the hook at the tip of the rod through a special shape. The purpose is to provide.

[0005]

According to the present invention, a wire rod, an optical cable, and the like are laid after a triplex type cable is laid using a surplus space in a pipeline already laid.
In the bamboo threading head attached to the end of the bamboo threading rod used for the bamboo threading operation, when the twist pitch of the triplex type cable is P and the sheath outer diameter of the triplex type cable is d, the length L of the bamboo threading head is P / 6 or more,
It is a bamboo thread head to the power cable conduit having a width W of d or more.

[0006]

When the twist pitch of the triplex cable is P and the sheath outer diameter of the triplex cable is d, the length L of the bamboo thread head is P / 6 or more.
Since the width W is equal to or more than d, the bamboo thread head does not fall on the side surface of the triplex type cable and does not get caught between the inner surface of the conduit and the bamboo head.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a bamboo threading head for a power cable conduit according to the present invention will be described below with reference to the drawings. FIG.
It is a top view which shows the external appearance of a bamboo thread head. That is, at the tip of the bamboo rod 1, an elliptical head 5 having a length L and a width W is provided.
Attach. The width W of the head 5 is d or more, where d is the sheath outer diameter of the existing triplex cable. If the width W is smaller than d, the bamboo rod 1 with the head 5 attached to the tip is connected to the triplex cable 3.
The head 5 enters between the cores of the triplex-type cable when inserted into the pipeline in which the cable is laid. As a result, the head 5 is guided by the twist of the triplex type cable, and the bamboo rod 1 is wound around the triplex type cable.

[0008] The length L of the head 5 is at least 1/6 of the twist pitch P of the triplex type cable. FIG. 2 shows the head 5 placed on the triplex cable 3. FIG. 2B and FIG.
It is AA section and BB section of (A). Head 5
When the front part of the cable is about to fall to the left side of the triplex cable 3, the rear part is about to fall to the right side of the triplex cable 3. For this reason, if the length L of the head 5 is equal to or more than 1/6 of the twist pitch P, the head 5 is less likely to fall on the side surface of the triplex cable 3. If the length L of the head 5 is much smaller, the head 5 easily falls on the side surface of the triplex cable 3 and is caught between the triplex cable 3 and the inner surface of the pipeline 4.

At this time, since the head 5 is preferably as light as possible, it is preferable to form the head 5 from a material such as aluminum or hard plastic. The four corners of the head 5 should be rounded as much as possible so that the seam or the bend of the pipe 4 is not caught. Although the holes for the hooks are not shown in this figure, they are provided as a matter of course.

Next, data obtained by actually conducting an experiment on a bamboo shoot while changing the length L of the head will be shown.

As an existing triplex type cable,
66kVCVT3 × 200mm ² (twist pitch P ≒ 15
00 mm, sheath outer diameter d ≒ 50 mm). As head A, width 88 mm, length 250 mm (≒ P / 6)
And head B as width 85 mm and length 100 mm (Ｂ
P / 15). The experimental results are shown in Table 1 below.
As shown in FIG.

[0012]

[Table 1]

Next, a modification will be described. As shown in the sectional view of FIG. 3, even if a head 5a having a curved surface having the same curvature as the outer diameter of the triplex-type cable is used, the same effect is obtained because the head 5a is covered with the existing triplex-type cable 3. A similar effect was obtained by using a head 5b formed in a trough shape as shown in FIG.

[0014]

As described above, by using the bamboo threading head for the power cable conduit of the present invention, it becomes extremely easy to install an optical cable or the like in the conduit in which the power cable is laid. As a result, the route after the laying can be secured without constructing a new pipeline, which is economical. Further, it can also be used for laying in an optical fiber temperature radar in a pipeline, and the temperature monitoring of a power cable in the pipeline can be easily constructed.

[Brief description of the drawings]

FIG. 1 is a top view of a bamboo thread head showing an embodiment of the present invention;

FIGS. 2A, 2B, and 2C show a state in which a bamboo threading head is inserted into a conduit in which a triplex type cable is laid, FIG. 2A is a side view, and FIG. Is A in (A)
-A sectional view, (C) is a BB sectional view of (A),

FIG. 3 is a sectional view of a bamboo thread head showing a modification of the present invention;

FIG. 4 is a sectional view of a bamboo thread head showing another modification of the present invention;

FIG. 5 is a top view of a conventional bamboo thread head,

6 (A) and 6 (B) show a state in which bamboo threading is performed in a conduit in which a triplex type cable is laid using a conventional bamboo threading rod, and FIG. 6 (A) is a cross-sectional view. ,
(B) is a side view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bamboo rod 2 Hook 3 Triplex type cable 4 Pipeline 5,5a, 5b Bamboo thread head

Continuation of the front page (72) Inventor Ryo Mizuzu 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Prefecture, “Inside the Hidaka Factory, Hitachi Cable, Ltd.” (56) Reference: Japanese Utility Model Application Hei 3-60814 (JP, U.S.A.) (Japanese) Heisei 3-91006 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02G 1/08 H02G 9/00, 9/04

Claims (1)

(57) [Claims] When a wire rod, an optical cable, or the like is to be installed later using a surplus space in a pipeline in which a triplex type cable is already installed, the triplex type cable is attached to a tip end of a bamboo rod used for a bamboo threading operation. When the twist pitch of the triplex type cable is P and the sheath outer diameter of the triplex type cable is d, the length L of the bamboo threading head is at least P / 6 and the width W is at least d. The bamboo threading head to the power cable conduit, characterized by the following.