Cable removing method

Abstract

To provide a cable removing method in which when removing a three-phase cable, a work of disassembling a connection part and drawing out three cables, etc. can be efficiently performed so that a time required for the removing work can be significantly reduced.SOLUTION: A representative configuration of a cable removing method according to the present invention is a cable removing method for removing a three-phase cable 100 laid in an underground pipe line 20 and a manhole 30. The method includes cutting, in the manhole 30, a connection part 110 where the three-phase cable 100 is connected in the manhole 30 multiple times, sequentially carrying the cut pieces of the connection part 110 out to the outside of the manhole 30, collectively drawing out three cables 102 of the three-phase cable 100 after the connection part 110 is cut and delivering the cable to above the ground, and cutting the delivered three-phase cable 100 in a prescribed length above the ground.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a cable removal method for removing a three-phase cable laid in an underground conduit and a manhole. [Background technology]

[0002] In recent years, underground cabling has become increasingly common in cities due to considerations of aesthetics and safety. In underground cabling, troughs and conduits are buried underground, and power cables, communication cables, etc. (hereinafter referred to as underground cables) are laid inside them. Underground cables are removed when they deteriorate over time or are no longer needed.

[0003] As a method for removing an underground cable, for example, Patent Document 1 discloses a "method for removing an underground ultra-high voltage power transmission cable that has been laid for a long time in an underground conduit connecting two manholes." The underground ultra-high voltage power transmission cable removal method in Patent Document 1 includes "a step of providing a temporary hook in the earthen floor of a manhole that has the terminal end of one of the two ends of the power transmission cable that needs to be removed, both ends of which have been cut in advance, a step of connecting a hydraulic jack to the temporary hook, a step of connecting the terminal end of the power transmission cable to the hydraulic jack, and a step of driving the hydraulic jack and using its pulling force to pull the power transmission cable from the conduit into the manhole against lateral pressure and its own weight pressure." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7177537 Summary of the Invention [Problem to be solved by the invention]

[0005] When the power transmission method is a three-phase, three-wire system, a three-phase cable is used, with three cables forming one circuit. POF (Pipe Oil Filled) cables, which are well known as three-phase cables, have three (three-phase) cable cores placed inside a steel pipe, and the steel pipe is filled with insulating oil, an insulating material, to cover the cable cores.

[0006] When removing an underground cable from a manhole, if there is only one underground cable, a method can be applied in which "both ends of the power transmission cable are cut in advance and a termination for connection to a hydraulic jack is formed," as described in Patent Document 1. In contrast, the above-mentioned POF cable (three-phase cable) is welded to a connection part inside the manhole. Therefore, when removing a POF cable from a manhole, it is first necessary to cut and disassemble the connection part, and then remove the disassembled connection part from inside the manhole.

[0007] When cutting and dismantling a POF cable connection, it is first necessary to remove the weld between the steel pipe of the POF cable and the connection by gouging or other methods. For this reason, dismantling a POF cable connection requires more time and effort than dismantling the connection of other cables. Therefore, there was a need to improve work efficiency. In addition, because the connection of a POF cable is larger than the connection of other cables, there are more cutting points, which also contributes to the longer work time.

[0008] As described above, once the connection is removed from inside the manhole, the cable is extracted. In Patent Document 1, a pulling eye is attached to the end of the three-phase cable that has been cut off from the connection, and the pulling eye is pulled by a pulling machine such as a hydraulic jack, thereby extracting the underground cable from the conduit. However, this method requires a significant amount of time to completely reel in all three cables of the three-phase cable, resulting in low work efficiency and prolonged line outages.

[0009] In view of these problems, the present invention aims to provide a cable removal method that can efficiently perform tasks such as dismantling connections and pulling out three cables when removing a three-phase cable, thereby significantly reducing the time required for the removal work. [Means for solving the problem]

[0010] In order to solve the above problems, a typical configuration of the cable removal method of the present invention is a cable removal method for removing three-phase cables laid in underground pipelines and manholes, characterized in that the connection parts connecting the three-phase cables together in the manhole are cut multiple times inside the manhole, the cut connection parts are sequentially carried out of the manhole, the three cables of the three-phase cable after the connection parts have been cut are pulled out together and sent out toward the ground, and the sent out three-phase cable is cut to a predetermined length on the ground.

[0011] After cutting the above-mentioned connection, and before pulling out the three cables of the three-phase cable, it is advisable to crimp sleeves that extend the three cables onto the ends of each of the three cables protruding from the conduit.

[0012] When pulling out the three cables, it is advisable to grasp the three cables together using a pulling device equipped with a reaction receiver inserted into the center of the three cables protruding from the conduit and a grasping clamp that urges each of the three cables toward the reaction receiver.

[0013] In this cable removal method, a vehicle having a cable cutting device mounted on the loading platform is placed on the ground, and the three-phase cable that has been fed out is cut on the loading platform by the cable cutting device. [Effects of the Invention]

[0014] According to the present invention, a cable removal method can be provided that allows the three cables that make up a three-phase cable to be pulled out of the conduit together and sent out of the manhole, significantly reducing the time required for the removal work and improving work efficiency. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram illustrating a work site where a three-phase cable is removed. [Figure 2] FIG. 1 is a diagram illustrating a three-phase cable. [Figure 3] 1 is a flowchart illustrating a cable removal method according to the present embodiment. [Figure 4] FIG. 10 is a diagram illustrating the work site after the connection portion has been removed. [Figure 5] 10A and 10B are diagrams illustrating a sleeve attached to the end of a cable. [Figure 6] FIG. [Figure 7] 10A to 10C are diagrams illustrating the operation of the crimping device when crimping a sleeve onto a cable. [Figure 8] FIG. 1 is a diagram illustrating a work site where a three-phase cable is to be pulled out. [Figure 9] FIG. [Figure 10] FIG. 2 is a diagram illustrating the details of the extraction device. [Figure 11] FIG. 10 is a diagram illustrating the rear main body as viewed from behind. [Figure 12] FIG. 10 is a diagram illustrating pre-processing for the extraction work. [Figure 13] FIG. 10 is a diagram illustrating the initial withdrawal (first time). [Figure 14] FIG. 10 is a diagram illustrating the initial withdrawal (second time). [Figure 15] 10A and 10B are diagrams illustrating the operation of the extraction device. [Figure 16] FIG. [Figure 17] FIG. 16(d) is an enlarged cross-sectional view of the blade of FIG. [Figure 18] FIG. 9 is an enlarged view of the transport vehicle of FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0016] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Dimensions, materials, and other specific values ​​shown in the embodiments are merely examples for facilitating understanding of the invention and, unless otherwise specified, do not limit the present invention. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0017] Fig. 1 is a diagram illustrating a work site 10 where a three-phase cable 100 is to be removed. As shown in Fig. 1, at the work site, conduits 20 are buried under a road surface 12, and manholes 30 for maintenance work are provided at predetermined intervals between the conduits 20.

[0018] 2A and 2B are diagrams illustrating a three-phase cable 100, with Fig. 2A being a cross-sectional view and Fig. 2B being a perspective view of the three-phase cable 100 (three cables 102). As shown in Figs. 1 and 2, the three-phase cable 100 (POF cable) is laid inside a conduit 20, which is a steel pipe, and the conduit 20 is filled with insulating oil (not shown) and pressurized.

[0019] As shown in Fig. 2(a), a three-phase cable 100 is made up of three cables 102a, 102b, and 102c. As shown in Fig. 2(b), the three cables 102a, 102b, and 102c have conductors 106 (segmented conductors) covered on their outer peripheries with sheaths 108, and skid wires 104 are wound around the outer peripheries of the sheaths 108. In the following description, the three cables 102a, 102b, and 102c will be referred to as cables 102 unless they are to be specifically distinguished from one another.

[0020] (Cable removal method) (Cutting off the connection (S602) and dismantling (S604)) 3 is a flowchart illustrating a cable removal method according to this embodiment. When removing a three-phase cable 100 (POF cable), first, the connection parts 110 connecting the three-phase cables 100 of multiple conduits 20 connected to a manhole 30 are cut multiple times (S602) and disassembled (S604). In the example shown in FIG. 1, two connection parts 110 (upper connection part 110a and lower connection part 110b) are arranged above and below inside the manhole 30.

[0021] The upper connection part 110a is hung from the ceiling 32 of the manhole 30 by a hook 40. The lower connection part 110b is fixed to the floor surface 34 of the manhole 30 by a fastener 42. In the following description, when there is no need to distinguish between the upper connection part 110a and the lower connection part 110b, they will simply be referred to as connection part 110.

[0022] In this embodiment, a configuration in which two connection parts 110 are arranged one above the other inside the manhole 30 is illustrated, but the present invention is not limited to this. The cable removal method of this embodiment can be applied even when there is one connection part 110 or when there are three or more connection parts 110.

[0023] (Crimping the sleeve 120 to the end of the cable 102 (S606)) FIG. 4 is a diagram illustrating the work site 10 after the connection portion 110 has been removed. After the connection portion 110 has been removed outside the manhole 30 in steps S602 and S604, sleeves are attached to the ends of each of the three cables 102 of the three-phase cable 100 before they are pulled out. This is because the length of the cables 102 protruding from the wall surface of the manhole 30 is too short to be easily grasped by the pulling device 400. Therefore, as shown in FIG. 4, a crimping device 300 is placed inside the manhole 30. Then, using the crimping device 300, sleeves 120 are crimped onto the ends of each of the three cables 102 protruding from the conduit 20, extending them (S606).

[0024] Figure 5 is a diagram illustrating a sleeve 120 attached to the end of the cable 102. Figure 5(a) is a cross-sectional view of the sleeve 120. Figures 5(b) and 5(c) are diagrams illustrating the attachment of the sleeve 120 to the end of the cable 102.

[0025] As described above, a sleeve 120 as shown in Fig. 5(a) is attached to the end of the three-phase cable 100, i.e., the end of the three cables 102, after the connection part 110 (see Fig. 1) has been cut off inside the manhole 30. The sleeve 120 has an insertion hole 122 into which the conductors at the end of the cables 102 can be inserted, and an I-bolt 124 is connected to the tip.

[0026] When attaching the sleeve 120 to the end of the cable 102, first, the coating 108 (resin) is stripped from the end of the cable 102 to expose the conductor 106 (metal). Next, as shown in Fig. 5(b), the exposed conductor 106 is inserted into the insertion hole 122 of the sleeve 120. Then, as shown in Fig. 5(c), multiple crimping portions 126 (e.g., six portions) are formed in the sleeve 120, thereby crimping and attaching the sleeve 120 to the end of the cable 102.

[0027] Figure 6 is a diagram illustrating the crimping device 300. Figure 6(a) is a front view of the crimping device 300, and Figure 6(b) is a side view of the crimping device 300. The crimping device 300 shown in Figures 6(a) and 6(b) is a device that crimps a sleeve 120 onto the end of a three-phase cable 100 (cable 102). In the following description, the extension direction of the three-phase cable 100 is defined as D1, the rotation direction about the extension direction D1 as an axis is defined as D2, the vertical direction perpendicular to the extension direction is defined as D3, and the horizontal direction perpendicular to the extension direction is defined as D4.

[0028] The crimping device 300 of this embodiment includes a fixed die 310, a movable die 320 movably connected to the fixed die 310, and a drive source 330 that drives the movable die 320. The fixed die 310 is held by a rotation device 350 and is a substantially U-shaped member having a slide groove 312 along which the movable die 320 can slide. The fixed die 310 also has a crimping surface (hereinafter referred to as a fixed-side crimping surface 314) at the end of the slide groove 312, on which the cable 102 is placed.

[0029] The movable die 320 is a member that can slide within the slide groove 312 of the fixed die 310, and the surface that faces the fixed-side crimping surface 314 of the fixed die 310 is a crimping surface (hereinafter referred to as the movable-side crimping surface 324). The movable die 320 is connected to a driving source 330, and is driven by the driving source 330 to move in a direction toward and away from the fixed die 310.

[0030] A feature of the crimping device 300 shown in Figure 6 is that the fixed die 310 has four escape holes 316a, 316b, 316c, and 316d formed therein, into which the remaining two cables 102 can be inserted when one of the three cables 102 constituting the three-phase cable 100 is positioned between the fixed side crimping surface 314 and the movable side crimping surface 324.

[0031] When viewed from the end face direction, the three cables 102 are located at the vertices of an equilateral triangle. Therefore, when the crimping position (between the fixed-side crimping surface 314 and the movable-side crimping surface 324) is taken as one vertex of the equilateral triangle, relief holes 316a, 316b, 316c, and 316d are provided at the positions of the other two vertices. Note that, although this embodiment illustrates a configuration in which four relief holes 316a-316d are formed in the fixed die 310, the minimum number of relief holes can be reduced to two by moving the position and angle of the fixed die 310 more than described below.

[0032] As shown in Figure 6, the crimping device 300 of this embodiment further includes a rotation device 350 (movement in the D2 direction) that rotates or moves the fixed die 310 and the movable die 320, a vertical movement device 360 ​​(movement in the D3 direction), and a horizontal movement device 370 (movement in the D1 and D4 directions).

[0033] The rotation device 350 rotates the fixed die 310 and the movable die 320 in a rotation direction D2 (in a plane perpendicular to the extension direction D1 of the three-phase cable 100) around the axis of the extension direction D1 of the three-phase cable 100. The rotation device 350 of this embodiment is configured to include an outer frame 352, an inner frame 354, and rollers 356.

[0034] The outer frame 352 is a circular member disposed on the front and rear sides of the fixed die 310 and the movable die 320, and is fixed to the frame 340. The inner frame 354 is a circular member disposed inside the outer frame 352, and is fixed to the fixed die 310. The rollers 356 are fixed to the outer frame 352 and support the edges of the inner frame 354 so that they can run.

[0035] According to the above configuration, when the handle 332 of the driving source 330 is rotated in the D2 direction, the fixed die 310, the movable die 320, and the driving source 330 rotate together. This allows the angle of the fixed die 310 relative to the three cables 102 (i.e., the positions of the relief holes 316a-d) to be rotated.

[0036] The vertical movement device 360 ​​moves the fixed die 310 and the movable die 320 in a vertical direction D3 perpendicular to the extension direction D1 of the three-phase cable 100. The vertical movement device 360 ​​is a jack disposed between the bottom plate 342 of the frame 340 and the base 344. Thus, by extending or contracting the jack, which is the vertical movement device 360, the frame 340 moves up and down relative to the base 344, and the fixed die 310 and the movable die 320 can be moved up and down.

[0037] The horizontal movement device 370 moves the fixed die 310 and the movable die 320 in horizontal directions (the extending direction D1 of the three-phase cable and the perpendicular direction D4). In this embodiment, the horizontal movement device 370 is, for example, a caster attached to the underside of the pedestal 344. This allows the fixed die 310 and the movable die 320 to be moved horizontally together with the frame 340 supported by the pedestal 344.

[0038] 7A and 7B are diagrams illustrating the operation of the crimping device 300 when crimping the sleeve 120 onto the cable 102. When crimping the sleeve 120 onto three cables 102, first, the fixed die 310 and the movable die 320 of the crimping device 300 are separated from each other as shown in FIG.

[0039] The crimping device 300 is moved in the extending direction D1 of the three-phase cable, and the cable 102a, whose tip is covered with the sleeve 120 (see FIG. 5(b)), is inserted into the crimping position (between the fixed-side crimping surface 314 and the movable-side crimping surface 324). At this time, the remaining two cables 102b and 102c are inserted into the relief holes 316b and 316c, respectively, and are then retracted. This allows the cable 102a to be crimped to be inserted into the crimping position without the remaining two cables 102b and 102c hitting the fixed die 310.

[0040] Then, the driving source 330 moves the movable die 320 close to the fixed die 310, and the sleeve 120 is crimped by the fixed crimping surface 314 and the movable crimping surface 324, thereby crimping the sleeve 120 onto the cable 102a (see FIG. 5(c)).

[0041] After the sleeve 120 is crimped onto the cable 102a, the crimping device 300 is moved in the direction D1 and removed from the three cables 102. Next, as shown in FIG. 7(b), the fixed die 310 and the movable die 320 are rotated 180 degrees relative to the frame 340 by the rotation device 350 (upside down).

[0042] Then, the horizontal movement device 370 moves the fixed die 310 and the movable die 320 horizontally to the right in the figure, and the vertical movement device 360 ​​moves the fixed die 310 and the movable die 320 downward in the figure. This completes the alignment of the cable 102c with the fixed-side crimping surface 314 of the fixed die 310.

[0043] After the alignment is complete, the crimping device 300 is moved in the direction D1, and the cable 102c is inserted into the crimping position, and the remaining two cables 102a and 102b are inserted into the relief holes 316c and 316d, respectively, and then retracted. Then, as described above, the movable die 320 is brought close to the fixed die 310 to crimp the sleeve 120, thereby crimping the sleeve 120 onto the cable 102c.

[0044] After the sleeve 120 has been crimped onto the cable 102c, the crimping device 300 is removed from the three cables 102, and the fixed die 310 and the movable die 320 are moved horizontally to the left in the drawing by the horizontal movement device 370, as shown in Figure 7(c). This completes the alignment of the cable 102b with the fixed-side crimping surface 314 of the fixed die 310.

[0045] Once the alignment is complete, the crimping device 300 is moved in the D1 direction, and the cable 102b is inserted into the crimping position, and the remaining two cables 102a and 102c are inserted into the relief holes 316b and 316a, respectively, and then retracted. Then, as described above, the movable die 320 is brought close to the fixed die 310 to crimp the sleeve 120 and crimp the sleeve 120 onto the cable 102b. This results in the sleeve 120 being crimped onto the three cables 102.

[0046] According to the crimping device 300 described above, when the sleeve 120 is being crimped onto one of the three cables 102 that make up the three-phase cable 100, the other cables can be retracted into the relief holes 316a-d of the fixed die 310. This makes it possible to suitably prevent interference with the other cables when crimping one underground cable, thereby improving work efficiency.

[0047] In addition, the crimping device 300 of this embodiment can be applied to other cables such as OF cable (Oil Filled cable) and CV (Cross-linked polyethylene insulated vinyl sheath) cable in addition to POF cable, as long as the cable is a three-phase cable with three cables, so-called three cores.

[0048] (Pulling out the three-phase cable 100 (three cables 102) (S608)) Fig. 8 is a diagram illustrating a work site 10 where a three-phase cable 100 is pulled out. After the sleeves 120 are crimped onto the ends of the three cables 102 in step S606, a cable pulling device (hereinafter referred to as pulling device 400) is placed inside the manhole 30 as shown in Fig. 8. Then, using the pulling device 400, the three cables of the three-phase cable after the connection parts 110 have been cut are pulled out together and sent out toward the ground (S608).

[0049] Figure 9 is a diagram illustrating the extraction device 400. As shown in Figure 9, the extraction device 400 is configured to include a dolly 410, a main body 420, gripping clamps (a front clamp 452, a rear clamp 454), and a traveling cylinder 460. The dolly 410 is provided with wheels 412 on its bottom. This allows the extraction device 400 to travel on rails 50 laid on the bottom 34 of the manhole 30 in a direction toward and away from the wall surface 36a. A main body 420 is placed on the dolly 410.

[0050] Figure 10 is a diagram illustrating the details of the extraction device 400. Figure 10(a) is an enlarged view of the carriage 410 and main body 420 in Figure 2. Figure 10(b) is a two-sided view of the rear main body 440. Figure 10(c) is a two-sided view of the front main body 430.

[0051] As shown in Figures 9 and 10(a), the main body 420 is composed of a front main body 430 and a rear main body 440, which are divided into front and rear parts in the movement direction of the extraction device 400. This allows the weight per body to be lighter than when the main body is not divided. This therefore makes it possible to smoothly carry the device into and out of the manhole 30. However, this is not limiting, and the main body 420 may be configured as one body rather than being divided into two parts.

[0052] 10(b), the rear body 440 is a substantially Y-shaped member that is inserted into the center (between the cables 102) of the three cables 102 protruding from the conduit 20, and functions as a reaction force receiver. In detail, the rear body 440 has three fan-shaped ribs 442 that are equally spaced in the circumferential direction, and three grooves 444 into which the cables 102 are inserted are formed between the three ribs 442.

[0053] Rear clamps 454, which are clamps for gripping from three directions, are attached to the rear body 440 for the three grooves 444, respectively.

[0054] 10(c), the front main body 430 has a cable holding portion 430a arranged on the side close to the conduit 20, and a reaction force receiving portion 430b arranged on the side adjacent to the rear main body 440. The reaction force receiving portion 430b of the front main body 430 has three fan-shaped ribs 432 arranged at equal intervals in the circumferential direction, and three grooves 434 into which the cable 102 is inserted are formed between the three ribs 432. The cable holding portion 430a is cylindrical, and has an insertion hole 436 formed therein through which the cable 102 is inserted.

[0055] Front clamps 452, which are clamps for gripping the reaction force receiving portion 430b of the front main body 430, are attached to the three grooves 434 from three directions.

[0056] 11 is a diagram illustrating the rear main body 440 as viewed from the rear. When the gripping cylinder 456 connected to the gripping clamps (front clamp 452 and rear clamp 454) is driven, the rear clamp 454 moves toward the groove 444 as shown in FIG. 11. As a result, the cable 102 inserted into the groove 444 is urged (pressed) from three directions toward the rear main body 440 by the rear clamp 454. In the front main body 430, the cable 102 is urged by the front clamp 452 toward the groove 434 of the reaction force receiving portion 430b, which receives the reaction force.

[0057] 9, the extraction device 400 is provided with a traveling cylinder 460 that pushes the wall surface 36a of the manhole 30 on the pipeline 20 side to allow the carriage 410 to travel. In this embodiment, a total of three traveling cylinders 460 are provided: two (one not shown) on the upper part of the main body 420 and two on the lower part of the main body 420.

[0058] A front end 462 of the traveling cylinder 460 (the end on the right side in the drawing, close to the wall surface 36a) is connected to the manhole-side plate 472 via a connecting rod 490. Strictly speaking, the front end 462 of the traveling cylinder 460 is the tip of a piston (described later) housed inside the traveling cylinder 460.

[0059] The manhole-side plate 472 is connected to a load cell-side plate 474 attached to the wall surface 36a of the manhole 30. The rear end 464 of the traveling cylinder (the end on the left side in the drawing, away from the wall surface 36a) is connected to an end plate 482. A wheel 482a that travels on the rail 50 is provided on the lower part of the end plate 482.

[0060] Figure 12 is a diagram illustrating pre-processing for the extraction work. Figure 12(a) illustrates the state before the extraction device 400 is placed in the manhole 30 of Figure 1. As illustrated in Figure 12(a), the cut conduit 20 protrudes from the wall surface 32, and the conductor 106 of the cable 102 is exposed from the conduit 20. In addition, rails 40 for the extraction device 400 to travel on are laid on the bottom 34 of the manhole 30.

[0061] 12(a), the length of the cable 102 protruding from the wall surface 32 is short, and the cable 102 cannot be grasped by the pulling device 400. For this reason, in the initial pulling-out, the cable 102 is engaged with the pulling device 400 by the pulling rod 140 and pulled out.

[0062] Figure 12(b) is a diagram illustrating the parts used for the pre-processing and initial extraction of the extraction work. For the pre-processing of the extraction work, the sleeve 120, connecting screw shaft 130, extraction rod 140, fixing plate 150, and nut 160 shown in Figure 12(b) are used. The connecting screw shaft 130 is a shortened version of the extraction rod 140.

[0063] The end of the sleeve 120 is an I-bolt 124. The connecting screw shaft 130 has a screw 134 at its end, and the pull rod 140 also has a screw 144 at its end. The connecting screw shaft 130 and the pull rod 140 are also internally threaded at the ends opposite the screws 134 and 144. The fixing plate 150 has a hole 152 through which the screw 144 can be inserted, and is used in combination with a nut 160.

[0064] Fig. 12(c) is a diagram illustrating a state in which pre-processing for the pulling operation has been performed inside the manhole 30 of Fig. 12(a). In the pre-processing for the pulling operation, the conductor 106 of the cable 102 is inserted into the inside of the sleeve 120 as shown in Fig. 12(c). Then, the sleeve 120 is crimped onto the conductor 106 of the cable 102.

[0065] 13A and 13B are diagrams illustrating the initial withdrawal (first time). First, as shown in FIG. 13A, the connecting screw shaft 130 is attached to the I-bolt 124 of the sleeve 120. Then, the extraction rod 140 is attached to the screw 134 of the connecting screw shaft 130. This connects the connecting screw shaft 130 and the extraction rod 140 to the sleeve 120.

[0066] Next, as shown in FIG. 13(b), the screw 144 of the extraction rod 140 is inserted into the hole 152 (see FIG. 12(b)) of the fixing plate 150 and fastened with the nut 160. This causes the extraction rod 140 to be locked to the main body 420 of the extraction device 400. Next, as shown in FIG. 13(c), the extraction device 400 is moved in a direction away from the conduit 20. This causes the three cables 102 to be extracted from the conduit 20 via the connecting screw shaft 130 and the extraction rod 140 (first initial extraction).

[0067] Figure 14 is a diagram illustrating the initial removal (second time). After the first initial removal of the three cables 102 as shown in Figure 13(c), the removal device 400 is moved (returned) toward the wall surface 32 as shown in Figure 14(a). Then, the removal rod 140 is removed from the connecting screw shaft 130.

[0068] Next, as shown in Figure 14(b), the screw 134 of the connecting screw shaft 130 is inserted into the hole 152 of the fixing plate 150 and fastened with the nut 160. Next, as shown in Figure 14(c), when the pulling device 400 is moved in a direction away from the conduit 20, the three cables 102 are pulled out of the conduit 20 via the connecting screw shaft 130 and the pulling rod 140 (second initial pulling). These two initial pulling operations make it possible to pull out the cables 102 to an extent that they can be grasped by the main body 420 of the pulling device 400.

[0069] 15A and 15B are diagrams illustrating the operation of the pulling device 400. When pulling out three cables 102 of a three-phase cable 100 protruding from the conduit 20 in the wall surface 36a of the manhole 30, the three cables 102 are first inserted into the insertion hole 436 of the cable holding portion 430a of the front main body 420, the groove 434 of the reaction force receiving portion 430b, and the groove 444 of the rear main body 440 (see FIG. 4), as shown in FIG. 15A. Then, the front clamp 452 and the rear clamp 454 are driven by the gripping cylinder 456 to urge the cables 102 against the reaction force receiving portion 430b and the rear main body 440. As a result, the three cables 102 are gripped by the main body 420.

[0070] 15(a), when the traveling cylinder 460 is driven, the piston 460a is pushed out from the traveling cylinder 460, and as a result, the main body 420 travels on the rails 50 inside the manhole 30 and moves in a direction away from the pipeline 20, as shown in FIG. 15(b). As a result, the three cables 102 held by the main body 420 are pulled out of the pipeline 20 by a length substantially equal to the amount of movement of the main body 420.

[0071] As shown in FIG. 15(b), once the main body 420 has finished moving on the rail 50, the gripping clamps (front clamp 452, rear clamp 454) release the cables 102. Then, by retracting the piston 460a, the main body 420 is moved toward the wall surface 36a, as shown in FIG. 15(c). Then, by repeating the operations shown in FIGS. 15(a)-(c) described above, the cables 102 can be pulled out of the conduit 20 and simultaneously let out the cables 102 toward the ground. The three cables 102 let out by the cable pulling device 400 are pushed out of the manhole 30 from the ground through the guide pipe 60 (see FIGS. 4 and 8) inserted into the manhole 30, and sent out onto the ground.

[0072] The above-described pulling device 400 can pull the three cables 102 that make up the three-phase cable 100 out of the conduit 20 all at once and send them out of the manhole 30. In particular, by biasing the cables 102 toward the rear main body 440 and the reaction force receiving portion 430b, which receive the reaction force, the cables 102 are stabilized and can be biased strongly, allowing them to be securely gripped. Therefore, a large pulling load can be applied to pull out all three cables at once. This significantly reduces the time required for the removal work and improves work efficiency compared to the conventional method of using a hydraulic jack to pull out the cables one by one.

[0073] (Cutting of three-phase cable 100 (three cables 102) (S610)) After the three-phase cable 100 is fed out onto the ground from the manhole 30 in step S608, the three-phase cable 100 is cut on the ground using a cable cutting device (hereinafter referred to as cutting device 500) (S610). As shown in Figures 8 and 18, a transport vehicle 70 is placed on the ground, and the cutting device 500 is loaded on the bed of the transport vehicle 70. The underground cable 102 fed out onto the ground is guided to the cutting device 500 by the end of the guide pipe 60.

[0074] Figure 16 is a diagram illustrating the cutting device 500. Figure 16(a) is a front view of the cutting device 500 before cutting the three-phase cable 100. Figure 16(b) is a side view of the cutting device 500 of Figure 3(a). Figure 16(c) is a top view of the cutting device 500 of Figure 16(a). Figure 16(d) is a front view of the cutting device 500 when cutting the three-phase cable 100.

[0075] The cutting device 500 shown in FIG. 16 includes a pair of blades 510, a frame 520, and driving devices 532, 534.

[0076] 16(a), the pair of blades 510 includes an upper blade 512 arranged above the three-phase cable 100 inserted into the cutting device 500, and a lower blade 514 arranged below it. The frame 520 is fixed above the stand 540, and includes an upper frame 522, a lower frame 524, and a pair of vertical frames 526a, 526b connecting them.

[0077] The upper blade 512 is held by an upper frame 522 of a frame 520, and is operated by a drive unit 532 attached to the upper frame 522 in a direction to move toward and away from the lower blade 514. The lower blade 514 is held by a lower frame 524 of the frame 520, and is operated by a drive unit 534 attached to the lower frame 524 in a direction to move toward and away from the upper blade 512. As shown in Figure 16(b) , the pair of blades 510 are disposed adjacent to each other so as to be slidable in the insertion direction of the three-phase cable 100 into the cutting device 500.

[0078] In this embodiment, of the pair of blades 510, the upper blade 512 has a V-shape with the center recessed upward. The lower blade 514 has a V-shape with the center recessed downward. Note that in this embodiment, the upper blade 512 and the lower blade 514 have been illustrated as having a V-shape, but this is not limiting. The upper blade 512 and the lower blade 514 may also have a U-shape with the center recessed, or an arc-shape with the center recessed.

[0079] When cutting a three-phase cable 100 using the cutting device 500 of this embodiment, first, the three-phase cable 100 is inserted between the spaced apart upper blade 512 and lower blade 514, as shown in Fig. 16(a). As shown in Fig. 16(b), the cutting device 500 of this embodiment is provided with a guide tube 550 that guides the three-phase cable 100 between the spaced apart upper blade 512 and lower blade 514. This allows the three-phase cable 100 to be efficiently inserted between the upper blade 512 and lower blade 514.

[0080] Once the three-phase cable 100 is positioned between the upper blade 512 and the lower blade 514, the drive units 532, 534 are driven. As a result, the upper blade 512 and the lower blade 514 move and slide toward each other, as shown in Figure 16(d). This prevents the skid wire 104 from slipping away, and the three-phase cable 100 is cut all at once.

[0081] Figure 17 is an enlarged cross-sectional view of blade 510 in Figure 16(d). As shown in Figure 17, upper blade 512 and lower blade 514 that make up blade 510 have their cutting edges 512a and 514a chamfered. That is, upper blade 512 and lower blade 514 are chamfered so that their cutting edges 512a and 514a form obtuse angles. This configuration can effectively prevent chipping of the blade due to hard skid wire 104 made of steel wire, allowing blade 510 to be used for a long period of time.

[0082] Fig. 18 is an enlarged view of the transport vehicle 70 of Fig. 8. After the three-phase cable 100 is cut using the cutting device 500 as described above, the cut three-phase cable 100a is loaded onto the transport vehicle 70. Therefore, when cutting the three-phase cable 100, it is advisable to cut it into lengths L (for example, 500 cm) that can be loaded onto the bed of the transport vehicle 70.

[0083] The cutting device 500 described above can cut all three-phase cables 100 at once after they have been pulled out of the manhole 30. Therefore, compared to the conventional method of pulling out the three underground cables 102 of the three-phase cable 100 one by one, the time required for the removal work can be significantly reduced, and work efficiency can be improved.

[0084] Furthermore, by cutting the three-phase cable 100 at predetermined lengths on the loading platform of the transport vehicle 70, a large reel is not required and the cut three-phase cable 100a can be transported as is by the transport vehicle 70. This makes it possible to improve the efficiency of the transport work and simplify the equipment.

[0085] As described above, according to the cable removal method of this embodiment, all of the steps, including the steps of cutting and dismantling the connection part 110, crimping the sleeve 120 to the cable end, pulling out the cable, and cutting the cable, can be optimized for the three-phase cable 100. Therefore, it is possible to dramatically reduce the time and labor required to remove the three-phase cable 100 from the manhole 30 compared to the conventional method.

[0086] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that these modifications and alterations also fall within the technical scope of the present invention. [Industrial Applicability]

[0087] The present invention can be used in a cable removal method for removing three-phase cables laid in underground conduits and manholes. [Explanation of symbols]

[0088] 10...work site, 12...road surface, 20...pipe, 30...manhole, 32...ceiling, 34...floor, 36...wall, 36a...wall, 38...exit, 40...hook, 42...fixing device, 50...rail, 60...guide pipe, 70...transport vehicle, 100...three-phase cable, 100a...three-phase cable, 102...cable, 102a...cable, 102b...cable, 102c...cable, 104...skid wire, 106...conductor, 108...coating, 110...connection , 110a...upper connecting portion, 110b...lower connecting portion, 120...sleeve, 122...insertion hole, 124...I bolt, 126...crimping portion, 300...crimping device, 310...fixed die, 312...slide groove, 314...fixed side crimping surface, 316a...relief hole, 316b...relief hole, 316c...relief hole, 316d...relief hole, 320...movable die, 324...movable side crimping surface, 330...driving source, 332...handle, 340...frame, 342...bottom plate, 344...base , 350...rotation device, 352...outer frame, 354...inner frame, 356...roller, 360...vertical movement device, 370...horizontal movement device, 400...pulling device, 410...cart, 412...wheel, 420...main body, 430...front main body, 430a...cable holding portion, 430b...reaction force receiving portion, 432...rib, 434...groove, 436...through hole, 440...rear main body, 442...rib, 444...groove, 452...front clamp, 454...rear clamp, 456...gripping cylinder, 46 0...Travel cylinder, 460a...Piston, 462...Front end, 464...Rear end, 472...Manhole side plate, 474...Load cell side plate, 482...End plate, 482a...Wheel, 490...Connecting rod, 500...Cutting device, 510...Blade, 512...Upper blade, 514...Lower blade, 520...Frame, 522...Upper frame, 524...Lower frame, 526a...Vertical frame, 526b...Vertical frame, 532...Driver, 534...Driver, 540...Stand, 550...Guide tube

Claims

1. A cable removal method for removing a three-phase cable laid in an underground conduit and a manhole, comprising: Cutting the connection portion connecting the three-phase cables together in the manhole multiple times within the manhole, The cut connection portions are sequentially carried out of the manhole, After the connection portion is cut, the three cables of the three-phase cable are pulled out together and sent out toward the ground. A cable removal method characterized by cutting the fed three-phase cable to a predetermined length on the ground.

2. The cable removal method according to claim 1, characterized in that after the connection is cut, and before the three cables of the three-phase cable are pulled out, sleeves that extend the three cables are crimped onto the ends of each of the three cables protruding from the conduit.

3. When removing the three cables, a reaction force receiver inserted into the center of the three cables protruding from the conduit; a holding clamp that urges each of the three cables toward the reaction force receiver; Using a drawing device equipped with 2. The cable removal method according to claim 1, wherein three cables are gripped together.

4. A vehicle with a cable cutting device mounted on the platform is placed on the ground, 2. The cable removal method according to claim 1, wherein the fed three-phase cable is cut on a loading platform by the cable cutting device.

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