JP3745304B2 - A cable laying inner pipe, a method of inserting a cable into the cable laying inner pipe, and a method of laying the cable - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes an inner pipe for laying a cable installed in a state of surrounding a cable laid in a pipe line provided in the underground, a method for inserting the cable into the inner pipe for laying the cable, and connecting the cable to the pipe It relates to improvements to the method of laying on the road.
[0002]
[Prior art]
Conventionally, a plurality of cables used for communication or the like are laid in a pipe line that is an inner space of a pipe buried in the ground. Thus, when laying a plurality of cables in the pipeline, an operation of inserting (withdrawing) these cables into the pipeline is performed. However, the outer peripheral surface of each cable often has a large friction coefficient based on the material of the outer coating. In addition, when adopting a method in which each cable is laid bare in the pipeline, the existing cable in the pipeline and the new cable drawn into the pipeline may be entangled with each other. . For this reason, if a method of laying each cable as it is in the pipeline is adopted, when the new cable is pulled into the pipeline, a large area is formed at the contact portion between the outer peripheral surface of the new cable and the outer peripheral surface of the existing cable. The frictional force works, and not only the force required to pull in the cable is increased, but in a significant case, there is a possibility that each cable is damaged due to a large tension acting on each cable. Such an inconvenience also occurs when the cables are pulled out from the pipes in order to remove the cables from the pipes.
[0003]
Therefore, in order to eliminate such inconvenience, in recent years, as described in, for example, Japanese Patent No. 2506097, a cable to be laid in a pipeline is inserted inside the inner pipe inserted in the pipeline. The method has been adopted. FIG. 9 shows a conventional inner pipe 1 used in such a case. The inner pipe 1 is formed in a cylindrical shape as a whole by a plastic material (elastic material that expands and restores substantially elastically) such as high-density polyethylene and having a small surface friction coefficient.
[0004]
The operation of laying a cable in a pipeline using such an inner pipe 1 is performed as follows. First, as shown in FIG. 10, the inner pipe 1 is inserted into a conduit 3 that is an inner space of the tube 2. In the illustrated example, before the inner pipe 1 is inserted into the conduit 3 in this way, a case where one cable 4 is already laid bare in the conduit 3 is shown. Next, as shown in FIG. 11, the cable 4 is inserted (drawn) into the inner pipe 1. As shown in FIG. 12, the operation of drawing the cable 4 into the inner pipe 1 as described above is performed by inserting one end (the left end in FIG. 12) of the drawing string 5 inserted in advance into the inner pipe 1. This is done by pulling the other end (the right end in FIG. 12) of the pull-in cord 5 in a state where it is coupled to the pull-in rope 13 provided at the end of the cable 4. Further, FIG. 13 shows that the above-described inner pipe 1 is used to add another cable 4 or 4 to the pipe line 3 in which the cable 4 or 4 is already laid as shown in FIG. It shows the laid state. In this way, when another cable 4 or 4 is additionally laid in the pipeline 3, the laying operation is performed in the same procedure as that shown in FIGS.
[0005]
If a plurality of cables 4, 4 are laid in the pipeline 3 using the inner pipe 1 as described above, the outer circumferences of the cables 4, 4 are drawn when the cables 4, 4 are drawn into the pipeline 3. There is no contact between the faces. That is, at this time, the outer peripheral surface of each of the cables 4 and 4 has a small friction coefficient, and the inner peripheral surface of the inner pipe 1 (in the case of one cable 4 previously laid on the pipe 3). Is in contact with the outer peripheral surface of the inner pipe 1. For this reason, when the cables 4 and 4 are pulled into the pipe 3, the force required to pull the cables 4 or 4 increases, or a large tension acts on the cables 4 and 4 to cause the cables 4 and 4 to be pulled. It is possible to prevent inconvenience such as breakage of 4. In addition, such an effect is similarly applied to the case where the cables 4 and 4 are removed from the pipe 3 (the inner pipe 1) in order to remove the cables 4 and 4 from the pipe 3. can get.
[0006]
[Problems to be solved by the invention]
In the case of the above-described prior art, when the cable 4 is laid in the pipeline 3, the operation of inserting the inner pipe 1 into the pipeline 3 and the operation of drawing the cable 4 inside the inner pipe 1 Are performed separately (in order). For this reason, the number of steps of laying work increases, and this laying work requires a lot of time. Further, the work of drawing the cable 4 into the inner pipe 1 is performed using the draw string 5 inserted through the inner pipe 1. For this reason, one pull-in string 5 is required for each inner pipe 1 to be used, and the cost of the inner pipe 1 increases.
The cable laying inner pipe, the method of inserting a cable into the cable laying inner pipe, and the method of laying the cable of the present invention have been invented to eliminate the above-mentioned disadvantages.
[0007]
[Means for Solving the Problems]
Among the cable laying inner pipe of the present invention, the method for inserting a cable into the cable laying inner pipe, and the cable laying method, the cable laying inner pipe according to claim 1 is a conduit for laying the cable. It is used in a state where this cable is inserted inside the cable.
In particular, the cable laying inner pipe according to claim 1 has a cut extending from the inner peripheral surface to the outer peripheral surface at one place in the circumferential direction. And by extending the width of the cut, the cable can be inserted into the inside through the widened portion.
[0008]
In the case of the inner pipe for cable laying according to the first aspect, the notch provided in the inner pipe is formed at the factory at the time of manufacturing the inner pipe at the same time as or after the manufacturing work of the inner pipe. In addition, after the inner pipe is conveyed to a use site without a cut, the inner pipe can be formed using a cutter such as a cutter at the use site. In addition to providing the cuts over the entire length of the inner pipe, for example, the cuts can be provided continuously in an intermediate portion excluding both ends of the inner pipe.
In addition, when the cut is provided over the entire length of the inner pipe, the cut is formed by tearing a part of the cylindrical inner pipe in the circumferential direction without a cut. It can also be formed on the basis of making the material rolled into a cylindrical shape.
[0009]
Further, in the method for inserting a cable into the cable laying inner pipe described in claim 2 , first, a cut extending from the inner peripheral surface to the outer peripheral surface at one circumferential direction of the cable laying inner pipe is made for this cable laying. One end of the cable through the widened part of the inner pipe, or while forming the cable from the one end side to the other end side of the inner pipe for laying the cable, The part is inserted inside the inner pipe for cable laying. Next, by relatively displacing the jig and the cable laying inner pipe and cable with respect to the axial direction of the cable laying inner pipe, the portion where the width of the cut is widened is directed toward the other end of the cut. Move. Then, the remaining part of the cable is gradually fed into the inner side of the cable laying inner pipe through the part where the width of the cut is widened and moves toward the other end side.
[0010]
Further, in the cable laying method according to claim 3 , first, after providing a cut in the circumferential direction of the cable laying inner pipe from the inner peripheral surface to the outer peripheral surface at one place in the circumferential direction, Or, while forming the cable laying inner pipe from one end side to the other end side, widening the width of the cut with a jig, the one end of the cable is connected to the cable laying inner pipe through the widened portion. Insert inside the pipe. Next, the width of the cut is widened by displacing the cable laying inner pipe and the cable toward one end in the axial direction of the cable laying inner pipe while the jig is substantially fixed. The part is moved toward the other end side of the cut. The cable laying inner pipe and the cable are then gradually fed into the inner side of the cable laying inner pipe through the widened part of the cut and moving toward the other end side. Are simultaneously fed from one end side of the inner pipe and the cable into a conduit for laying the cable.
[0011]
[Action]
According to the inner pipe for cable laying of the present invention as described above, the method for inserting a cable into the inner pipe for cable laying and the method for laying the cable, the operation of inserting the inner pipe into the conduit, and the cable to the inner pipe It is possible to perform the work of inserting the at the same time. For this reason, the number of steps of the laying work can be reduced, and the time required for the laying work can be shortened. Further, since the pull-in cord 5 (see FIG. 12) is not used when the cable is inserted into the inner pipe, the cost can be reduced as much as the pull-in cord 5 can be omitted.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1-5 has shown the 1st example of embodiment of this invention corresponding to all of Claims 1-3 . That is, this example is an example in which the cable 4 is laid in a state in which the cut 6 is formed over the entire length in the inner tube 1a described below in advance.
[0013]
The inner pipe 1a of the present example is made of a plastic material that is lightweight and has a small coefficient of friction on the surface, such as high-density polyethylene (an elastic material that expands and restores almost elastically). In particular, in the case of the inner pipe 1a of the present example, a cut 6 reaching the outer peripheral surface from the inner peripheral surface is formed at one place in the circumferential direction over the entire length, and is formed in parallel with the central axis of the inner pipe 1a. Then, when performing the cable laying operation described below, the cable 4 (FIGS. 4 to 5) is formed inside the inner pipe 1a through the widened portion by elastically expanding the width of a part of the cut 6. Can be inserted freely. The cut 6 is formed at the factory when the inner pipe 1a is manufactured, and after the inner pipe 1a is transported to the use site without the cut 6, a cutter or the like is used at the use site. It can also be formed.
[0014]
In the case of this example, a jig 7 for expanding a part of the cut 6 formed in the inner pipe 1a is used when a cable laying operation described later is performed. The jig 7 includes a main body 8 and a protruding portion 9. Of these, the main body 8 is formed in a partial cylindrical surface on both sides in the width direction {front and back direction in FIG. 3A, up and down direction in FIG. 3B, left and right direction in FIG. The both end edges of the both side surfaces in the width direction with respect to the length direction of the main body 8 (the left-right direction in FIGS. 3A and 3B and the front-back direction in FIG. 3C) are made continuous with each other. With this configuration, the planar shape of the main body 8 is configured in a streamline shape such that the width dimension is the largest in the central portion in the length direction, and becomes smaller toward the both ends from the central portion in the length direction, Furthermore, the length direction both ends edge of the said main body 8 is comprised so that it may become a pointed edge, respectively. As shown in FIG. 3C, the lower end surface of the main body 8 is a semi-cylindrical surface along the inner peripheral surface of the inner pipe 1a. Note that the vertical direction is based on the drawings, and does not necessarily represent the posture in use.
[0015]
Further, the protruding portion 9 is provided so as to protrude from the upper surface of the main body 8, and the one end in the length direction of the main body 8 toward the tip side {the left end side in FIGS. 3A and 3B , Incline in a direction toward the back side in FIG. Further, the cable through-hole 10 is inserted into the jig 9, the tip end surface of the protruding portion 9 and the other end in the length direction of the main body 8 {the right end edge in FIGS. 3A and 3B, FIG. C) is provided in a state of opening to the lower end portion of the front side edge}. The inner diameter of the cable through hole 10 is larger than the outer diameter of the cable 4 described below. In the case of this example, the jig 7 is configured to be divided into two in the width direction. That is, the jig 7 is configured by combining a pair of elements 11a and 11b divided into two in the width direction. The protruding portion 9 can be omitted.
[0016]
The operation of laying the cable 4 in the pipe line 3 which is the inner space of the pipe 2 using the inner pipe 1a configured as described above is performed as follows. First, as shown in FIG. 4, the jig 7 is attached to one end of the cut 6 formed in the inner pipe 1 a (the right end of FIGS. 4 to 5) from one end edge of the cut 6. Push toward the middle. Specifically, the jig 7 and the inner pipe 1a are brought close to each other in a state in which one end edge in the length direction of the jig 7 which is a sharp edge is slightly inserted into one edge portion of the cut 6. Relative displacement in the direction. As a result, the width of the notch 6 is guided on both side surfaces of the jig 7 and spreads almost elastically, and the jig 7 is pushed into one end of the notch 6. In the case of this example, the lower end surface of the main body 8 constituting the jig 7 is a semi-cylindrical surface along the inner peripheral surface of the inner pipe 1a. For this reason, when the jig 7 is pushed into one end portion of the cut 6 as described above, the lower end portion of the main body 8 can be prevented from interfering with one end edge of the inner pipe 1a, and the pushing operation can be performed smoothly. The Further, it is possible to secure a sufficient amount of pushing the lower end portion of the jig 7 into the inner pipe 1a.
[0017]
Further, before and after the operation of pushing the jig 7 into one end portion of the cut 6 as described above, the tip of the cable 4 is inserted into the cable through hole 10 provided in the jig 7, and the cable 4 is The jig 7 is inserted into the inner pipe 1a through the portion where the width of the cut 6 is widened. The operation of inserting the tip end of the cable 4 into the cable through hole 10 in this way is normally performed by inserting the tip end of the cable 4 from the opening of the cable through hole 10 on the protruding portion 9 side. . However, because the terminal having the outer diameter larger than the inner diameter of the cable through hole 10 is attached to the front end of the cable 4, the end of the cable 4 is connected to the opening of the cable through hole 10. When the cable 7 cannot be inserted, the operation of inserting the tip end portion of the cable 4 into the cable through hole 10 is performed before the jig 7 is pushed into one end portion of the notch 6. That is, in this case, before the jig 7 is pushed into one end of the notch 6, the butted surfaces of the pair of elements 11a and 11b constituting the jig 7 are opened and formed on these butted surfaces. The portion near the one end of the cable 4 is arranged between a pair of grooves for constituting the cable through hole 10. In this state, the two butted surfaces are butted together. As a result, the end portion of the cable 4 is inserted into the cable through hole 10.
[0018]
In any case, if the above-described work is performed and the inner pipe 1a and the jig 7 are combined and the cable 4 is inserted through the jig 7 as shown in FIG. Next, with the jig 7 being substantially fixed (for example, fixed by an operator's hand or supported and fixed to a fixed portion), the inner pipe 1a and the distal end portion of the cable 4 are moved. The cable 4 is simultaneously drawn into the inside of the pipe 3 for laying. In the case of this example, this drawing operation is performed in a state where one end of a drawing string (not shown) previously inserted through the pipe line 3 is coupled to the inner pipe 1a and the tip of the cable 4. This is done by pulling the other end of the string from the far end side of the conduit 3. As a result, the jig 7, the inner pipe 1a, and the cable 4 are relatively displaced in the axial direction. Accordingly, as shown in FIG. 4 to FIG. 5, the width of the cut 6 is increased toward the other end of the cut 6 (the left side of FIGS. 4 to 5). The remaining portion of the cable 4 is gradually fed into the inner pipe 1a through the widened portion. Then, the inner pipe 1a and the cable 4 are simultaneously inserted into the pipe line 3. As described above, the pull-in string used when pulling the inner pipe 1a and the cable 4 into the pipe line 3 is originally used for pulling the inner pipe 1a into the pipe line 3 (the conventional technique described above). This is necessary) and is different from the drawing string 5 for drawing the cable 4 inside the inner pipe 1 shown in FIG.
[0019]
According to the cable laying method of this example as described above, the operation of inserting the inner pipe 1a into the conduit 3 and the operation of inserting the cable 4 through the inner pipe 1a can be performed simultaneously. For this reason, the number of steps of the laying work can be reduced, and the time required for the laying work can be shortened. Further, when the cable 4 is inserted inside the inner pipe 1a, the pull-in cord 5 (see FIG. 12) as described above is not used, and therefore the cost can be reduced by the amount that the pull-in cord 5 can be omitted.
In the case of implementing this example, a mechanism for restoring the width of the widened cut 6 to the original width may be added to the jig 7.
[0020]
Next, FIGS. 6 to 7 show a second example of the embodiment of the present invention corresponding to claims 2 to 3 only. That is, this example is an example in which the cable 4 is laid while the cut 6 is formed in the inner pipe 1b described below.
In the case of this example, the cut 6 is not formed in the inner pipe 1b before the cable 4 is laid. That is, in this state, the structure of the inner pipe 1b is the same as that of the conventional inner pipe 1 shown in FIG.
[0021]
When laying the cable 4 by using the inner pipe 1b as described above, as shown in FIGS. 6 to 7, the jig for the feeding direction of the inner pipe 1b (right direction in FIGS. 6 to 7) is used. 7 is fixed to the rear side (left side in FIGS. 6 to 7) of the blade 7. Then, as shown in FIGS. 6 to 7, while feeding the inner pipe 1b into the pipe 3, the notch 6 is formed in the inner pipe 1b from the leading edge of the inner pipe 1b (the right edge in FIGS. 6 to 7). The cable 4 is laid in the same manner as in the first example shown in FIGS. 4 to 5 while being formed toward the rear edge (the left edge in FIGS. 6 to 7).
[0022]
As described above, in the case of this example, the cut 6 provided in the inner pipe 1 b is formed simultaneously with the laying operation of the cable 4. For this reason, prior to the laying operation of the cable 4, it is possible to save the trouble of forming the cut 6 in the inner pipe 1b in advance. Accordingly, it is possible to further reduce the time required for the laying operation of the cable 4 and reduce the cost.
[0023]
In carrying out the present invention, when the inner pipe 1a having the cut line 6 is formed over the entire length as shown in FIG. 1, the cut line 6 is the circumference of the cylindrical inner pipe having no cut line. In addition to forming the inner pipe by cutting a part of the direction, for example, the inner pipe can be formed by rolling a strip-shaped material into a cylindrical shape. Further, when the inner pipe is made by rolling the strip-shaped material into a cylindrical shape in this way, the shape of the inner pipe 1c is as shown in FIG. It is possible to make the shape overlapped and to function as the cut 6 between the overlapped portions.
[0024]
【The invention's effect】
The cable laying inner pipe of the present invention, the method of inserting the cable into the cable laying inner pipe, and the cable laying method are configured and act as described above, so that the time required for the cable laying operation is shortened. Cost can be reduced.
[Brief description of the drawings]
1A and 1B show a first example of an embodiment of the present invention, in which FIG. 1A is an end view of an inner pipe, and FIG.
FIG. 2 is a perspective view of a jig.
3A and 3B are views of the jig viewed from three directions, in which FIG. 3A is a front view, FIG. 3B is a plan view, and FIG. 3C is a right side view.
FIG. 4 is a perspective view showing an initial stage of cable laying work.
FIG. 5 is a perspective view showing an end stage in the same manner.
FIG. 6 is a view similar to FIG. 4, showing a second example of an embodiment of the present invention.
7 is a view similar to FIG.
FIG. 8 is a partial perspective view showing another example of the inner pipe.
FIGS. 9A and 9B show an example of a conventional inner pipe, wherein FIG. 9A is an end view, and FIG. 9B is a partial perspective view.
FIG. 10 is a partial perspective view showing a state where an inner pipe is inserted into a pipeline.
FIG. 11 is a partial perspective view showing a state in which a cable is inserted through an inner pipe inserted into a pipeline.
FIG. 12 is a schematic perspective view showing a situation in which a cable is pulled into the inner pipe.
FIG. 13 is a partial perspective view showing a state in which a plurality of cables are laid on a pipe line.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 1a, 1b Inner pipe 2 Pipe 3 Pipe line 4 Cable 5 Pull-in string 6 Cut 7 Jig 8 Main body 9 Protruding part 10 Cable through-hole 11a, 11b Element 12 Cutlery 13 Pull-in rope

Claims (3)

  In the inner pipe for cable laying that is inserted into the conduit for laying the cable and used inside this cable, there is a cut extending from the inner peripheral surface to the outer peripheral surface at one place in the circumferential direction. An inner pipe for laying a cable, characterized in that by extending the width of the cut, the cable can be inserted inside the widened portion.   After providing a cut in the cable laying inner pipe at one location in the circumferential direction from the inner peripheral surface to the outer peripheral surface in the cable laying inner pipe, or from one end to the other end of the cable laying inner pipe While extending the width of this cut with a jig, one end of the cable is inserted inside the inner pipe for cable laying through the widened portion, and then the jig and the cable laying are formed. By moving the inner pipe and the cable relative to each other in the axial direction of the inner pipe for laying the cable, the portion where the width of the cut is widened is moved toward the other end of the cut, and toward the other end. Move, through the widened part of the cut, gradually send the remaining part of the cable inside the inner pipe for cable laying, Method of inserting a cable into Buru laying the inner pipe.   After providing a cut in the cable laying inner pipe at one location in the circumferential direction from the inner peripheral surface to the outer peripheral surface in the cable laying inner pipe, or from one end to the other end of the cable laying inner pipe The width of the cut is widened with a jig while forming one end of the cable through the widened portion into the inner pipe of the cable laying, and then the jig is substantially In the fixed state, the cable laying inner pipe and the cable are displaced toward one end in the axial direction of the cable laying inner pipe, so that the widened portion of the cut is moved to the other end of the cut. The remaining portion of the cable is passed through the widened slit and moved toward the other end. Gradually fed into the inside of the flop, and these inner pipe and cable cabling to the conduit for laying the cable, fed these inner pipe and simultaneously from one end of the cable, laying the cables.

Images