JPH0980237A - How to handle excess cable length - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a method for treating a cable extra length portion which can prevent buckling of the cable when an earthquake or the like occurs and can secure a sufficient extra length even in a relatively narrow place. According to the present invention, a pipeline 2 in which a cable 1 is laid.
In the method of forming the extra length portion 4 of the cable 1 in the end side space 3 and performing the treatment of the extra cable length portion 4, the extra length portion 4 of the cable is wound with a predetermined diameter to form a winding portion 6, When the cable 1 is pulled toward the side of the pipe line 2, the winding portion 6 is integrally held by a holding member 7 that is broken by the pulling force of the cable 1 without being bent by a bending radius less than the allowable minimum bending radius of the cable 1. It is the one.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of treating an extra cable portion formed in an end side space of a pipe line in which a cable such as a manhole is laid.

[0002]

2. Description of the Related Art It is well known to connect a plurality of manholes (or handholes) with pipelines and lay communication and power cables in these pipelines to form an underground line.
Then, an extra length of cable is made inside the manhole, and this extra length can absorb expansion and contraction of the cable due to temperature, or facilitate branching / connection work for subsequent expansion / route change. it can.

FIGS. 5 to 7 show a conventional method for treating a cable extra length portion. First, in the example shown in FIG.
The extra length c of the cable b is wound and bundled one or more times inside the manhole a, and the extra length c is fixed to the inner wall of the manhole a with a rope or the like. Further, in the example shown in FIG. 6, the extra length portion c is bent in a meandering shape and left or fixed inside the manhole a. In the example of FIG. 7, the duct (usually a trough) is not inside the manhole d
The cable b is meandered inside to form an extra length portion c, and at the time of connection or the like, the cable b is pulled out to the inside of the manhole to perform work.

Incidentally, such a method of treating the extra length portion is adopted not only in the underground line but also in general indoor / outdoor wiring.

[0005]

However, the above-mentioned conventional method has the following problems.

In the method shown in FIG. 5, when an earthquake or the like occurs, one of the manholes moves or the pipeline collapses, the cable is significantly pulled, the bending radius of the cable becomes small, and the worst cable is acceptable. There is a risk of buckling when the bending radius is less than or equal to the bending radius. In the method shown in FIGS. 6 and 7, since the meandering cable takes up a relatively large space, it is not possible to secure a sufficient extra length inside the manhole or the like, and particularly in the method shown in FIG. 7, a sufficient extra length is secured. Therefore, it is necessary to cause the cable to meander in the pipe over a long distance, which requires a great deal of labor for the installation work.

Therefore, the present invention was devised to solve the above problems, and its purpose is to prevent buckling of a cable when an earthquake or the like occurs and to provide a sufficient extra length even in a relatively narrow place. An object of the present invention is to provide a method of processing an extra cable length that can be secured.

[0008]

In order to achieve the above object, a method of treating a cable extra length portion according to a first aspect of the present invention is directed to a cable extra portion in a space on an end side of a pipe line in which the cable is installed. In the method of forming a long portion and treating the cable surplus portion, the cable surplus portion is wound with a predetermined diameter to form a winding portion, and when the cable is pulled toward the conduit side, the cable is allowed to The winding portion is integrally held by a holding material that is broken by its tensile force without being bent under a minimum bending radius.

Further, the present invention according to claim 2 is based on claim 1.
In the above-described method for treating an extra cable portion, the holding material is made of a material having excellent water resistance and corrosion resistance.

The present invention according to claim 3 provides the invention according to claim 1.
In the method for treating the excess cable length portion according to any one of claims 1 to 2, the winding portion is formed by winding the excess cable length portion in a figure 8 shape or an SZ shape.

The present invention according to claim 4 provides the invention according to claim 1.
In the method for treating the excess cable length portion according to any one of claims 1 to 3, the holding material is fixed in the end side space of the conduit after holding the winding portion.

Further, the present invention described in claim 5 is based on claim 1.
In the method for treating an extra cable length portion according to any one of claims 4 to 4, the winding portion winds the extra cable length portion along a surface substantially perpendicular to a cable introduction direction into the end side space of the conduit. It will be.

According to the first aspect of the present invention, when the cable is pulled by an earthquake or the like, the holding material is partially broken by the pulling force, and the cable of the winding portion is paid out by the pulled length. On the other hand, the remaining holding material holds the winding portion at a predetermined diameter.

According to the second aspect of the present invention, since a material having excellent water resistance and corrosion resistance, such as Styrofoam, is used, retention of the winding portion and long-term reliability of breakage due to tensile force are maintained.

According to the third aspect of the present invention, the cable is not unduly twisted. According to the fourth aspect of the present invention, the winding portion does not move in the manhole and the cable is not damaged (buckling, crushing, breaking, etc.).

According to the fifth aspect of the present invention, the cable of the winding portion can be paid out so that the bending is not tight and the twisting is not applied.

[0017]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view for explaining a method for treating an extra cable length portion according to the present invention. As shown in FIG. 1 (a), the cable 1 extends from a conduit 2 to a manhole (end side). It is drawn into the space 3 to form an extra length portion 4 having a sufficient length. More specifically, two or more conduits 2 (only one is shown) are connected to the manhole 3, and as shown by the arrow, the cable 1 is drawn from one conduit 2 and the other conduit (not shown). Sent to. And at this time the cable 1
It is drawn in more than the distance between the pipe lines 2 or more than the length to be sent out, and is drawn to the ground, for example, without being twisted, whereby a sufficient length of extra length is secured and the extra length of the cable 1 is obtained. The part 4 will be formed. After that, the cable 1 of the extra length portion 4 is bent into a shape of a figure 8 in a state of being laid on the floor of the manhole 3, and after being bundled into a plurality of figures of a figure 8, it is vertically raised as illustrated. . At the stage of being bent in the shape of figure 8, the bending radius is a predetermined diameter, that is, the allowable minimum bending radius of the cable 1 or more, and by being bent in the shape of figure 8, the cable 1 is not twisted or kinked. Since there is no mark, damage to electric wires and communication lines inside the cable is prevented. As described above, the winding portion 6 is formed by bending or winding the cable 1 of the extra length portion 4 into the shape of a figure 8.

FIG. 2 is a schematic plan view showing the winding portion 6 which is vertically arranged. As can be seen from this figure, the winding portion 6 is bundled into four bundles.
It is formed by two 8-shaped portions 5. Each of the eight-shaped portions 5 is along a plane perpendicular to the introduction direction of the cable 1 drawn from the pipe line 2, in other words, the extra length portion 4
Is bent into a figure eight along its vertical plane. Next, as shown in FIG. 1B, the lengthwise winding portion 6 is entirely covered and integrally fixed by a holding material 7 made of expanded polystyrene. Specifically, a mold for accommodating the entire winding part 6 is set, and beads of styrofoam are put into this to be foamed and fixed. Holding material 7
Completely enters the gap between the cables 1 and retains the shape of the winding portion 6, and in particular enters the inside of the upper and lower rings 8 of the figure 8 portion, and the ring 8 is crushed by the weight of the cable 1 1
Is locally less than the allowable minimum bending radius.

Alternatively, as shown in FIG. 3, a styrofoam holding material 7a, which is formed by molding the winding portion 6, is prepared in advance, and the winding portion 6 is vertically held and then sandwiched from both sides to form a ring 8.
You may make it insert the columnar holding material 7b in the space of the center. Here, the holding material 7a is adapted to fit the cable 1 in the groove portion 7c formed in the inner surface portion thereof.

When the winding portion 6 is fixed or hardened in this manner, the holding member 7 is fixed to the floor portion 9 inside the manhole 3 such as the fixing member 10 or a bolt (not shown), as shown in FIG. 1C. It is fixed by the fixing means. When the position of the winding portion 6 is fixed in this way, the processing of the extra cable length portion 4 is completed.

According to the above treatment method, when the cable 1 is pulled to one side of the conduit due to an earthquake or the like, the holding member 7 is partially broken by the pulling force, and at the same time, the winding portion 6
The cable 1 of the pulled length is paid out from. On the other hand, the remaining holding material 7 holds the winding portion 6 in the initial shape. That is, since no deformation is given to the cable 1 that is not paid out, the cable 1 of the winding portion 6 can be held at the allowable minimum bending radius or more, buckling of the cable 1 is prevented, and the electric wire inside the cable 1 is prevented. It is also possible to prevent damage to communication lines and the like. Further, it is possible to avoid interruption of power supply and signal transmission when an earthquake occurs, and stable power supply and signal transmission can be performed.

In particular, since the winding portion 6 is arranged as shown in FIG. 2, the cable 1 can be paid out while the bending is relaxed, whereby excessive bending at the time of paying out can be prevented, and damage to the cable 1 can be prevented. It can be prevented. That is, cable 1
Is pulled from the direction perpendicular to the surface formed by the figure 8 portion, and is not pulled in the direction of reducing the diameter of the ring 8 of the figure 8 portion. Therefore, the cable 1 is paid out so that the bending is not tight, and it is possible to prevent buckling of the cable 1 and unnecessary breakage of the holding member 7. It is most preferable that the angle θ formed by the surface formed by the figure-eight portion 5 and the introduction direction of the cable 1 is vertical, that is, 90 °, but it is not impossible otherwise, and such a conduit 2 If there is a positional relationship between the winding portion 6 and the winding portion 6, it is preferable to provide a cable guide or the like so that the cable 1 is not bent as much as possible.

Further, in the above, since the holding material 7 is formed of styrofoam, breakage due to tensile force and winding 6
Thus, the optimum strength for the holding is obtained, and the holding material 7 is ideal. As described above, the workability is excellent, so that the winding portion 6 can be fixed easily and in a short time, and the light weight is preferable because it is easy to handle and the workability is excellent. Furthermore, it does not corrode even in a humid place such as the manhole 3,
High reliability can be secured.

Since the holding member 7 is fixed inside the manhole 3, even when the cable 1 is pulled, the winding portion 6 can be held at an accurate position without moving, and the holding member 7 is pulled by the pulling force. The breakage and the feeding of the cable 1 can be performed accurately and smoothly.

In addition, since the cables 1 are bundled in the shape of a figure 8, it is possible to secure a sufficient extra length while preventing the cables 1 from being habituated. Especially, it is possible to further improve the space efficiency by making the figure 8 long vertically.
Even at the time of feeding, the cable 1 is not twisted and feeding is very easy.

Now, the test results of the surplus cable portion treated by the above method and assuming an actual earthquake will be described below. A standard spacer type optical cable (outer diameter of about 14 mm) was used for the cable 1, and a manhole with a width of 900 mm, a height of 900 mm and a depth of 900 mm was used. The bending radius of the cable 1 of the extra length portion 4, that is, the radius R of the ring 8 is set to 200 mm so that the allowable minimum bending radius (140 mm when fixed) has a slight margin. Assuming that the extra length of the extra length part 4 is 10 m or less, the figure 8 part 5 is about 10 as 4 bundles (4 turns).
The extra length of m was secured.

From another manhole (not shown),
When the cable 1 was pulled at its allowable tension (280 kgf) at a speed of about 300 mm / s, the holding material 7 was broken and the cable 1 was fed out, so that only a slight tension of about 10 kgf was applied to the cable 1. Then, the holding material 7 was sequentially broken while keeping the bending of the winding portion 6, and the cable 1 was smoothly fed out. In this, no external damage or the like of the cable 1 was confirmed, which confirmed that the present method is very effective.

Next, a modified embodiment will be described.

In the modified embodiment shown in FIG. 4, the cable 1 of the extra length portion 4 is bent or wound in the SZ shape instead of the figure 8 shape to form the winding portion 6a. That is, the cable 1 drawn out from the conduit 2 is wound a predetermined number of times (4 turns) in a certain direction and then a predetermined number (4 turns) in the opposite direction.
It has been rewound. This prevents the cable 1 from being twisted or curled, and also prevents buckling of the internal electric wire. The winding portions 11a and 11b are integrally fixed in the vertical state by the holding member 7 and fixed in position by the fixing member 12. In each of the winding portions 11a and 11b, the cable 1 is bent with an allowable minimum bending radius or more, as in the above-described embodiment, and the surface formed by the loop portion 13 is perpendicular to the cable introduction direction. Even in this way, extreme bending when the cable 1 is pulled is prevented,
It is possible to obtain the same effects as the above-described embodiment, such as ensuring a sufficient extra length.

The present invention can be applied to various modifications other than the above-mentioned embodiments, and can be applied not only to underground lines but also to general indoor / outdoor wiring.

[0032]

The present invention exhibits the following excellent effects.

(1) According to the present invention described in claim 1,
It is possible to prevent the cable from buckling when an earthquake occurs, and to perform stable power supply and signal transmission.

(2) According to the invention of claim 2,
The long-term reliability of the holding material can be achieved.

(3) According to the present invention of claim 3,
The twisting of the cable can be prevented, and a sufficient extra length can be secured even in a relatively narrow place.

(4) According to the present invention of claim 4,
The breaking of the holding material and the feeding of the cable can be performed accurately and smoothly, and the reliability can be secured.

(5) According to the invention of claim 5,
It is possible to prevent damage when the cable is extended.

[Brief description of drawings]

FIG. 1 is a perspective view for explaining an embodiment of a method according to the present invention.

FIG. 2 is a plan view showing a winding portion.

FIG. 3 is a side view showing a modified example of a holding material.

FIG. 4 is a perspective view showing a modified example.

FIG. 5 is a schematic view showing a conventional example.

FIG. 6 is a schematic diagram showing a conventional example.

FIG. 7 is a schematic view showing a conventional example.

[Explanation of symbols]

 1 Cable 2 Pipeline 3 Manhole (space on the end side) 4 Extra length part 6,6a Winding part 7,7a, 7b Retaining material

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Shinichi Fujisaki 1-2425, Shirayamaura, Niigata City, Niigata Prefecture 2 Hokuriku Regional Construction Bureau, Ministry of Construction (72) Inventor Haruo Shimamura 3-2, Ishikin, Toyama City, Toyama Prefecture No. 37, Ministry of Construction, Hokuriku District Construction Bureau, Toyama Construction Office (72) Inventor Yoshiharu Ishida, 3-2, Ishigane 3-chome, Toyama City, Toyama Prefecture 37, Ministry of Construction, Hokuriku District Construction Bureau, Toyama Construction Office (72) Inventor Yoshifumi Kodaka, Ibaraki 5-11 Hidaka-cho, Hitachi, Ltd. Hidaka Plant, Hitachi Cable, Ltd. (72) Inventor Kazuhiro Higashikawa 1-3-10 Takaracho, Toyama City, Toyama Prefecture Hitachi Hokuriku Line Co., Ltd.

Claims (5)

[Claims] 1. A method of forming an extra length portion of a cable in a space on an end portion side of a pipe in which the cable is installed and treating the extra length portion of the cable, wherein the extra length portion of the cable is wound with a predetermined diameter. A winding member is formed so that when the cable is pulled toward the conduit side, the winding member is integrally held by a holding material that is broken by the pulling force of the cable without being bent below the allowable minimum bending radius of the cable. The method for treating an extra cable length is characterized in that 2. The method for treating an extra cable length portion according to claim 1, wherein the holding material is made of a material having excellent water resistance and corrosion resistance. 3. The method for treating an extra cable length portion according to claim 1, wherein the winding portion is formed by winding the extra cable length portion into a figure 8 shape or an SZ shape. 4. The method for treating an extra cable length portion according to claim 1, wherein the holding member is fixed in the end side space of the conduit after holding the winding portion. 5. The winding portion according to claim 1, wherein the extra cable length portion is wound along a surface substantially perpendicular to a cable introduction direction into the space on the end side of the conduit. How to handle excess cable length.