JPS5836563B2 - How to form a snake on a shelf cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of forming snakes in shelf cables.

When installing a K cable in a tunnel or in an open channel (hereinafter referred to as a tunnel), cable support shelves are installed at regular intervals along one side of the tunnel, and the cable is extended onto these shelves. There is.

In this cable installation on a shelf, the frictional force against movement of the cable is small, so in the case of power cables, measures must be taken to prevent thermal expansion and contraction of the cable during energization cycles.

For this reason, conventionally, after extending the cable on a shelf,
It is known to form a so-called horizontal snake by bending the cable sinusoidally with a pitch of, for example, 6 m in the horizontal plane along the entire length of the couple.

According to this horizontal snake cable installation, the thermal expansion and contraction of the cable is absorbed by the bending deformation of the snake, and this absorption is achieved uniformly along the entire length of the cable. mechanical damage can be well prevented.

In this cable installation method, the shape and dimensions of the snake are set so that the cable strain caused by bending the snake-like cable that has absorbed thermal expansion and contraction, mainly strain in the cable sheath and insulator, is kept within the allowable strain limit. This is necessary, and the snake width etc. are determined to meet this condition.

The snake width needs to be increased as the outer diameter of the cable becomes larger; for example, in the case of a cable with an outer diameter of 90 mm, the snake width becomes as wide as 135 ya.

However, in order to form such a wide snake on the above-mentioned cable on the shelf in the tunnel, it is necessary to increase the length of the cable support shelf according to the width of the snake. Reduction is forced, making it difficult to secure a passage within the tunnel, which not only impedes cable installation work after removing cable snakes, but also inconveniences maintenance and inspection work after cable installation.

As a cable snake installation method, in addition to the above-mentioned horizontal snake, the use of a vertical snake (a cable with a snake formed in a vertical plane) has been experimentally considered, but has it been put into practical use yet? stomach.

Since this vertical snake cable installation method occupies a very small space in the hH horizontal plane used for the above-mentioned installation of the passageway in the tunnel, the above-mentioned disadvantages in securing the passage in the tunnel can be eliminated.

The method of forming a snake on a shelf cable according to the present invention is a method that can accurately form a vertical snake with a predetermined snake width on a shelf cable, and is a method that can accurately form a vertical snake with a predetermined snake width on a shelf cable. Install detachable arms between the cable support shelves and at a lower location than the same shelf, extend the cables along the shelves, then slacken the cables and route the cables between the shelves as described above. It is characterized by being pushed under the arm and then removing the arm.

The present invention will be explained below with reference to the drawings.

Figure 1 shows a top view of the inside of the tunnel where the cable is laid, and
The end views of ■-■ shown in the figure are shown respectively.

In FIGS. 1 and 2, reference numeral 1 indicates one side wall surface within the sinus tract.

2, 2... are cable support shelves installed at regular intervals along the inner wall 1 of the tunnel via vertical metal fittings 1, z..., and the interval between the shelves 2, 2 is approximately 3 m. ing.

Cable extending rollers 3 are supported at the tips of these cable support shelves 2, 2....

These cable extending rollers 3, 3, . . . may be provided on the tunnel passage.

Reference numerals 4, 4, . . . are pillars erected in contact with the tunnel side wall 1 between the shelves 2, 2, and the same ones as the above-mentioned uprights γ are used.

To carry out the present invention, as shown in FIG. 1, the cable W is extended along the cable extension rollers 3, 3, . . . , and then the extended cable is shelf 2
, 2...Transferred above.

In this case, although not shown, a reasonable cable length is left in the cable drum.

After transferring cable W to the top of shelf 2, 2...
As shown in the figure, arm fittings 5,
5. Attach detachably.

The mounting height of this arm fitting 5 is determined by the height difference between this arm fitting 5 and the cable support shelf 2 (shown by h in Fig. 4).
It is set to match the snake width described later.

Further, as shown in FIG. 4, the length of the arm 5 is made shorter than the length of the cable support shelf 2, and a curved sliding plate 50 is attached to the lower surface of the arm fitting 5.

After attaching the arm 5 to several consecutive supports 41, 42... on the cable tip side as described above, the cable is connected to the cable drum (not shown) by a predetermined length. The cape tower of the cable support shelf span is paid out by a cable transfer device or the like, and the arm 5 is interposed. 1 to the vicinity of the tip of the arm 5 as shown by n in FIG. 4, and the pulled cable is forcibly pushed under the arm 5 as shown by arrow m in FIG.

In this case, the cables on the shelf 2 are also moved together with the cables into the closet m, as shown by the arrow f.

FIG. 5 shows a cable in which a vertical snake is formed on the distal end side of the cable as described above.

After forming the snake on the cable tip side in this way, the plurality of arms 5, 5 are connected as shown in FIG.
..., remove two or three of them near the tip of the cable, and then attach them below the inter-shelf cable where the snake is to be formed in the manner described above.
Form the next snake in the same manner as above, as shown by the dotted line in the figure.

In this case, the cable portion on which the snake has already been formed immediately before forming the next snake is suspended between the shelf 2 and the arm 5 in a meandering manner, and is firmly fixed by this meandering bending. Even if a tensile force is applied to the cable portion when forming the next snake, it will not move, and there is no fear that the shape of the snake will be disturbed.

Thereafter, the above-described snake formation is repeated toward a cable drum (not shown) to form a snake over the entire length of the cable.

The above explanation relates to one embodiment of the present invention, and as shown in Fig. 1, after the cable is extended on the wire extension roller, the cable is moved onto the shelf and the inter-shelf cable is pushed under the arm. You can also do these tasks at the same time.

In this case, as shown in FIG. 7, the length of the arm 5 is set to the length of the shelf 2 in order to smoothly route the cable as shown by the arrow X and push the cable under the arm 5 as shown by the arrow Y.
It is desirable to make it longer than the length of.

In addition, in the above explanation, the snake forming method was applied to a single cable, but if multiple cables are arranged, it can also be applied to a 3-strand cable made by bundling 3 single-core cables together with a tape body. It goes without saying that it is possible.

As described above, the present invention is a method of arranging an arm between cable shelves at a position lower than the shelf and pushing the inter-shelf cable under the arm to form a snake in the cable. Since the width is inevitably regulated by the height difference between the shelf and the arm, simply by adjusting the above height difference to the specified snake width dimension, the cable can be attached to the specified dimension without modifying the snake width dimension. Vertical snakes can be formed accurately.

In addition, the horizontal space occupied by the snake formation is small, and the cable snake installation can be easily accomplished even within a tunnel.

[Brief explanation of the drawing]

Figure 1 is a schematic top view showing the inside of the tunnel, Figure 2 is an end view of Figure 1, Figures 3, 4, 5, 6, and 7 are the main views. FIG. 2 is an explanatory diagram for illustrating the invention. In the figure, 2, 2... are cable support shelves, 5, 5...
... is an arm, and W is a cable.

Claims (1)

[Claims] 1 In a cable installation site where cable support shelves are installed at regular intervals, arms are removably installed between the cable support shelves and at a position lower than the shelves, and the cable is extended along the shelves. A method of forming a snake on a cable on a shelf, characterized in that the cable is then slackened, the cable between the shelves is pushed under the arm, and the arm is then removed.