Of cable pulling tool

Abstract

To provide a towing jig that is firmly attached to the end of an OF cable without the use of firearms or compression, can tow large capacity OF cables, and can be reused.SOLUTION: An outer sheath of the end of an OF cable 1 to be pulled is scraped off to expose only a conductor portion 2 for a certain length, an inner tube 3 is placed over the outer circumference of the conductor portion 2, a wedge 4 is driven into the conductor portion from the end face of the conductor portion 2 exposed at the tip opening of the inner tube 3, a pooling outer tube 5 with a blocked tip face is placed over the outer circumference of the inner tube 3, a screw is screwed into the conductor portion 2 through the screw hole 3c of the inner tube 3 from the screw hole 5d on the outer circumference of the pooling outer tube 5, and a protrusion 7 having an outer peripheral male screw is provided on the outer surface of the tip of the pooling outer tube 5. A vulcanized rubber layer 10 is formed on the outer circumference of the pooling outer tube 5 and the outer sheath 1a of the OF cable 1. A cylindrical cover 11 is covered and fixed to the outer circumference of this vulcanized rubber layer 10, and the protrusion 7 is capped with a pooling head 13.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a traction jig attached to the end of an existing OF cable laid in a pipeline or the like when pulling out the existing OF cable.

Background Art

[0002] As a method of pulling out an existing OF cable laid in a pipeline or the like, there is a method of attaching a pulling eye (traction jig) to the end of the OF cable, connecting a traction wire to the pulling eye, and pulling it out. In this case, in order to prevent oil leakage from the OF cable, it is necessary to seal the portion where the pulling eye is attached, and conventionally, the sealing has been performed by lead work of soldering.

[0003] The above lead work uses a fire tool such as a torch lamp or a propane burner for soldering, so there is a risk of fire, and the work is troublesome such as taking a long time. Moreover, the pulling eye connected by lead work cannot be reused.

[0004] Therefore, a method or structure for sealing the connection portion between the end of the OF cable and the pulling eye without using a fire tool such as lead work has been developed.

[0005] The one in Patent Document 1 is one of them. In an OF cable traction portion where the metal sheath and conductor at the end of the OF cable are gradually exposed, and a traction fitting is compression-fixed to the exposed conductor, a metal tube is fitted across the traction fitting and the exposed metal sheath, and both ends of this metal tube are respectively crimped onto the traction fitting and the metal sheath via a rubber layer and tightened with a binding wire.

[0006] Another example is from Patent Document 2. A method for removing an OF cable for removing an OF cable in which a spiral tube forming an oil supply path, a conductor bundle composed of a plurality of conductors, an oil-impregnated insulating layer impregnated with insulating oil, a shielding layer made of metal, and an anticorrosion layer are formed in this order from the center to the outside from a wiring path, the method comprising pulling out the spiral tube, detaching and pulling out at least one of the conductors from the conductor bundle, pulling out the remaining conductors, pulling out the oil-impregnated insulating layer, cutting the shielding layer at a cutting line extending in the axial direction, reducing the diameter of the shielding layer and the anticorrosion layer, and pulling out the shielding layer and the anticorrosion layer.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Disclosure of the Invention

Problems to be Solved by the Invention

[0008] However, since the structure of the Patent Document 1 covers the exposed conductor end of the OF cable with a traction fitting and compresses and fixes it, it can be used when the capacity of the OF cable is small. However, when the capacity of the OF cable is large, when the OF cable is pulled with a pulling eye, there is a risk that the traction fitting may be pulled out from the conductor end. In addition, since the traction fitting is covered on the conductor and compressed and fixed, the traction jig such as the traction fitting cannot be reused.

[0009] In addition, the method disclosed in Patent Document 2 involves pulling out the spiral tube at the center from one end of the OF cable to be removed, pulling out one conductor from the conductor bundle, and then pulling out the remaining conductor bundles in order from the inner layer to the outer layer at the center. After pulling out, a cutter is inserted into the pulled-out part to make an axial cut on the inner surface, and the shielding layer and anticorrosion layer are reduced in diameter and pulled out. Therefore, it requires many working steps and is a time-consuming removal method.

[0010] Therefore, in order to solve the above problems, the present invention aims to provide a traction jig for an OF cable that can firmly attach a traction jig to the end of the OF cable without using a firearm and without compressing it, can traction a large-capacity OF cable, and can be reused.

Means for Solving the Problems

[0011] In the invention of claim 1, the outer skin such as the anticorrosion layer and shielding layer at the end of the OF cable to be tractioned is scraped off to expose only a certain length of the conductor part at the center. An inner tube covers the outer periphery of the conductor part. A wedge is driven into the conductor part from the end face of the conductor part exposed at the tip opening of the inner tube. A pulling outer tube with a closed tip face covers the outer periphery of the inner tube. A screw is screwed through the screw hole of the inner tube from the screw hole on the outer periphery of the pulling outer tube to reach the conductor part. A short cylindrical protrusion with an external male thread is integrally provided on the outer surface of the tip of the pulling outer tube. A vulcanized rubber layer formed by winding a tape made of vulcanized rubber is formed on the outer periphery of the pulling outer tube and the outer periphery of the outer skin of the OF cable adjacent thereto. A cylindrical cover covers the outer periphery of this vulcanized rubber layer, and both ends of the cylindrical cover are fixed to the pulling outer tube and the outer skin. The protrusion is screwed and engaged into the fitting hole of a pulling head having a traction locking hole, serving as a traction jig for the OF cable.

[0012] Further, in the invention of claim 2, the cross-sectional shape of the inner tube is a shape in which a part of the circular outer edge is cut out, and the opening of the hollow portion into which the inner tube of the pulling outer tube is fitted has the same shape as the cross-sectional shape of the inner tube. After fitting the inner tube into the hollow portion of the pulling outer tube, the pulling outer tube is rotated about its axis, and an end portion of the inner tube is locked to a part of the peripheral edge of the opening of the pulling outer tube, making it impossible to pull out the pulling outer tube from the inner tube. This is the pulling jig for an OF cable according to claim 1.

[0013] Further, in the invention of claim 3, a small-diameter hole is provided that leads from the tip surface of the protruding body to the hollow portion of the pulling outer tube into which the inner tube is inserted, and a detachable sealing plug is provided at the tip of the small-diameter hole. This is the pulling jig for an OF cable according to claim 1 or 2.

[0014] Further, in the invention of claim 4, the cylindrical cover is divided into two in the longitudinal direction. The outer periphery of one divided edge is provided with an external male thread, and the inner periphery of the other divided edge is provided with an internal female thread. These external male thread and internal female thread are screwed together to form a configuration connected to one cylindrical cover. This is the pulling jig for an OF cable according to claim 1.

Advantages of the Invention

[0015] According to the invention of claim 1, the conductor portion at the end of the OF cable is exposed, the inner tube is crowned on the outer periphery of the conductor portion and fixed with a wedge, and further the pulling outer tube is screwed and crowned on the outer periphery of the inner tube. By simply winding a tape made of vulcanized rubber around the outer periphery of these connection points, the pulling jig can be fixed to the end of the OF cable to be removed. Thus, it is possible to firmly attach the jig without using a firearm as in the prior art and without compressing the jig at the end of the OF cable. Also, since a firearm is not used and compression is not performed in this way, the operation of attaching the pulling jig to the OF cable can be carried out quickly.

[0016] In addition, since the traction jig can be attached in this way, even a large-capacity OF cable can be tractioned. Also, since the traction jig is not compressed, after the traction of the OF cable is completed, the traction jig can be removed from the OF cable and reused for the traction of other OF cables. Further, a vulcanized rubber layer is provided on the outer circumferences of the OF cable and the pulling outer tube to prevent oil leakage from the connection part between the OF cable and the traction jig.

[0017] Also, according to the invention of claim 2, since the cross-sectional shape of the inner tube is a shape with a part of the circular outer edge cut out, and the opening of the hollow part into which the inner tube of the pulling outer tube is fitted has the same shape as the cross-sectional shape of the inner tube, by aligning the cross-sectional shape of the inner tube with the position of the opening of the end face of the pulling outer tube, the inner tube can be fitted into the hollow part of the pulling outer tube. Then, when the pulling outer tube is rotated around the axis, the end of the inner tube is locked to a part of the peripheral edge of the opening of the pulling outer tube, and the pulling outer tube cannot be pulled out from the inner tube, so that the inner tube and the pulling outer tube can be fixed more firmly.

[0018] Also, according to the invention of claim 3, a small-diameter hole is provided from the hollow part of the pulling outer tube to the tip surface of the protruding body integrally provided at the tip of the pulling outer tube, and the opening of the small-diameter hole at the tip surface of the protruding body is closed with a detachable sealing plug. Therefore, when tractioning the OF cable, the sealing plug can be opened to extract the oil inside the OF cable.

[0019] Also, according to the invention of claim 4, since the cylindrical cover is divided into two parts, when attaching the traction jig, one of the divided cylindrical covers is pre-covered on the outer circumference of the OF cable, and after the vulcanized rubber layer is formed, the other divided cylindrical cover is covered, and the two divided covers can be integrally connected, improving workability.

Brief Description of the Drawings

[0020]

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Embodiments for Carrying Out the Invention

[0021] (Embodiment Example 1) The traction jig A for the OF cable in Embodiment Example 1 of the present invention will be described with reference to FIGS. 1 to 10.

[0022] As shown in FIG. 2, this traction jig A for the OF cable scrapes off the outer skin 1a such as the anticorrosion layer and the shielding layer at the end of the OF cable 1 to be pulled, and exposes only the conductor part 2 at the center part by a certain length. Further, as shown in FIG. 1, an inner tube 3 is covered on the outer periphery of the exposed conductor part 2. And a wedge 4 is driven in around the oil supply path 2a at the end face of the conductor part 2 exposed at the end face of the inner tube 3. This wedge 4 functions to block the opening end of the oil supply path 2a and press the cable of the conductor part 2 against the inner periphery of the inner tube 3.

[0023] As shown in FIGS. 3 to 5, this inner tube 3 has the opposite outer side parts of the tubular body with a circular cross-section scraped off and flattened. Further, an inner peripheral tapered part 3b that opens toward the opening is formed at one end of the hollow part 3a with a circular cross-section inside. Further, a screw hole 3c that reaches the hollow part 3a from the outer peripheral surface is provided at the edge part on the side opposite to the inner peripheral tapered part 3b, and the screw holes 3c are provided every 90 degrees along the outer periphery of the inner tube 3, and these screw holes 3c are provided at two positions at intervals along the axial direction.

[0024] Then, as shown in Fig. 1, a pulling outer tube 5 is crowned on the outer periphery of the inner tube 3. As shown in Figs. 6 to 9, the pulling outer tube 5 is provided with a hollow portion 5a having a circular cross-section into which the inner tube 3 is inserted. One end of the hollow portion 5a is closed by a partition wall 5b, and the other end is provided with an opening 5c into which the inner tube 3 is inserted. As shown in Fig. 9, both sides of the circular opening 5c are flattened, and have substantially the same shape and size as the side surface shape of the inner tube 3 shown in Fig. 5.

[0025] Therefore, in order to crown the pulling outer tube 5 on the outer periphery of the inner tube 3, in accordance with the flattened portion of the inner tube 3, the orientation of the opening 5c of the pulling outer tube 5 is aligned, the inner tube 3 is placed into the hollow portion 5a, and then the pulling outer tube 5 is rotated 90 degrees about the axis. In this state, both sides of the end face of the inner tube 3 abut against the small-diameter opening edges of the opening 5c of the pulling outer tube 5, and the inner tube 3 cannot be pulled out from the pulling outer tube 5. The inner tube 3 in this state is shown by the dotted line in Fig. 9.

[0026] In this state, as shown in Fig. 1, screw holes 5d are provided at positions corresponding to the respective screw holes 3c on the outer periphery of the inner tube 3, which reach from the outer peripheral surface of the pulling outer tube 5 to the hollow portion 5a. Wood screws 6 are screwed in from the screw holes 5d of the pulling outer tube 5, and the tip portions of the respective wood screws 6 are screwed into the screw holes 3c of the inner tube 3 and further penetrate into the interior of the conductor portion 2 in the cavity 3a.

[0027] In addition, on the outer surface of the partition wall 5b of the pulling outer tube 5, a short columnar protrusion 7 having an outer periphery formed as an external male thread 7a is integrally provided with the pulling outer tube 5, and a small-diameter hole 7b is provided that communicates from the tip surface of the protrusion 7 to the hollow portion 5a of the pulling outer tube 5. A seal plug receiving portion 8 is provided at the tip of the small-diameter hole 7b, and a detachable seal plug 9 is provided at the seal plug receiving portion 8 (see Fig. 1). When pulling the cable, the seal plug 9 can be opened to drain the oil that has leaked from the oil supply passage 2a of the conductor portion 2 of the cable to be removed.

[0028] The outer sheath 1a of the OF cable 1 and the pulling outer tube 5 have substantially the same outer diameter, and as shown in FIG. 1, a tape made of vulcanized rubber is wound around the outer periphery of these to provide a vulcanized rubber layer 10.

[0029] Then, a cylindrical cover 11 is put on from above the vulcanized rubber layer 10. As shown in FIG. 10, the cylindrical cover 11 is composed of a short cylindrical cover piece 11a and a long cylindrical cover piece 11b that are divided into two in the longitudinal direction, and the short cylindrical cover piece 11a and the long cylindrical cover piece 11b are screwed together at the connection end by an internal peripheral female screw 11c and an external peripheral male screw 11d. Further, the diameters of the ends of the short cylindrical cover piece 11a and the long cylindrical cover piece 11b on the side opposite to the connection end are reduced, and one is superposed on the outer periphery of the outer sheath 1a and the other is superposed on the outer periphery of the end of the pulling outer tube 5, respectively, and a wood screw 12 is inserted into each screw hole 11e at the location and screwed to be fixed.

[0030] Further, the protruding body 7 is crowned with a pulling head 13. The pulling head 13 has a mating hole 13a formed on one end surface, and an internal peripheral female screw 13b screwed to the external peripheral male screw 7a of the protruding body 7 is provided on the inner periphery of the mating hole 13a. Further, a traction locking hole 13 is provided at the tip of the pulling head 13.

[0031] The traction jig A of the OF cable is configured with the above structure.

[0032] Next, the attachment procedure of the traction jig A of the OF cable to the OF cable 1 will be described with reference to FIGS. 11 to 17.

[0033] First, as shown in Step 1 of FIG. 11, the outer sheath 1a at the end of the OF cable 1 to be pulled is peeled off to expose a conductor portion 2 of a certain length, and the inner tube 3 is put on the outer periphery of the conductor portion 2. Then, the short cylindrical cover piece 11a of the cylindrical cover 11 is inserted in advance from the end of the OF cable 1 to the outer peripheral portion of the outer sheath 1a.

[0034] Next, as shown in Step 2 of FIG. 12, a wedge 4 is driven into the oil supply passage 2a at the center of the conductor portion 2 exposed on the outer end face of the inner pipe 3. As a result, the cable located on the outer periphery of the conductor portion 4 is in an open state to the outside, and the cable is pressed against the inner peripheral tapered portion 3b of the cavity 3a of the inner pipe 3. In this state, the inner pipe 3 cannot be pulled out from the conductor portion 2. At the same time, the opening end of the oil supply passage 2a is blocked by the wedge 4.

[0035] Thereafter, as shown in Step 3 of FIG. 13, the pulling outer pipe 5 is put on the outer periphery of the inner pipe 3. At that time, the small-diameter opening edge of the opening 5c of the pulling outer pipe 5 is aligned with the flat portion of the inner pipe 3 and inserted, and the inner pipe 3 is fitted into the hollow portion 5a of the pulling outer pipe 5. Thereafter, the pulling outer pipe 5 is rotated 90 degrees about its axis, and each screw hole 5d of the pulling outer pipe 5 is aligned with each screw hole 3c on the outer periphery of the inner pipe 3.

[0036] Then, as shown in Step 4 of FIG. 14, a wood screw 6 is inserted through each screw hole 5d, the wood screw 6 is turned, and the wood screw 6 is screwed into each screw hole 3c of the inner cylinder 3. Further, the tip of the wood screw 6 is pierced into the cable inside of the conductor portion 2. As a result, as shown in Step 5 of FIG. 15, the pulling outer pipe 5 is arranged and fixed side by side at the end of the outer skin 1a of the OF cable 1.

[0037] Next, as shown in Step 6 of FIG. 16, in order to prevent oil leakage from the side to the outer peripheries of these outer skins 1a and the pulling outer pipe 5, a tape 10 made of vulcanized rubber is wound around to form a vulcanized rubber layer 10. Then, as shown in Step 7 of FIG. 17, the long cylinder cover piece 11b of the cylindrical cover 11 is inserted from the tip of the pulling outer pipe 5 provided with the vulcanized rubber layer 10 on the outer periphery, and the inner peripheral female screw 11c of the short cylinder cover piece 11a and the outer peripheral male screw 11d of the long cylinder cover piece 11b are screwed together. A wood screw 12 is screwed into the screw holes 11e at both ends of the cylindrical cover 11 to fix the cylindrical cover 11. Thereafter, the pulling head 13 is screwed and fixed by screwing the inner peripheral female screw 13b of the mating hole 13a onto the outer peripheral male screw 7a of the protrusion 7 at the tip of the pulling outer pipe 5. Thus, the installation is completed.

[0038] In the above-described First Embodiment, the inner tube 3 has its opposite side portions of the tube body shaved off to be flattened, and accordingly, the opening 5c of the pulling outer tube 5 is shaped such that both sides of the circle are narrowed. However, the cross-sectional shape of the inner tube 3 is not limited to this. If the cross-sectional shape of the inner tube 3 is formed by notching a part of the outer edge of a circular cross-section, and the shape of the opening at the end of the hollow portion of the pulling outer tube 5 is made to conform to the cross-sectional shape of the inner tube 3, the same operation can be achieved. Alternatively, without doing so, the cross-sectional shape of the inner tube 3 can be kept circular, the opening of the pulling outer tube 5 can be made circular, and the mutual fixation between the inner tube 3 and the pulling outer tube 5 can be achieved only by screws such as wood screws, by aligning the positions of the screw holes 3c and 5d of both and screwing them together.

[0039] Furthermore, in the above-described First Embodiment, the small-diameter hole 7b and the sealing plug 9 that connect the hollow portion 5a of the pulling outer tube 5 and the tip surface of the protruding body 7 are provided, but this configuration is not an essential requirement of this invention. Also, the inner peripheral tapered portion 3b of the inner tube 3 is not an essential requirement of this invention. Also, the cylindrical cover 11 is divided into a short cylindrical cover piece and a long cylindrical cover piece, but it may be an integral cylindrical cover without being divided in this way. Furthermore, the material of the cylindrical cover 11 is not limited, and it may be made of resin. Also, not only the above-mentioned wood screws, but other screws can also be used.

Explanation of Reference Numerals

[0040] Traction jig for OF cable 1 OF cable 1a Outer sheath 2 Conductor part 2a Oil supply path 3 Inner tube 3a Cavity 3b Inner peripheral tapered portion 3c Screw hole 4 Wedge 5 Pulling outer tube 5a Hollow portion 5b Partition wall 5c Opening 5d Screw hole 6 Wood screw 7 Protruding body 7a Outer peripheral male thread 7b Small-diameter hole 8 Sealing plug receiver 9 Sealing plug 10 Vulcanized rubber layer 11 Cylindrical cover 11a Short cylindrical cover piece 11b Long cylindrical cover piece 11c Internal female thread 11d External male thread 11e Thread hole 12 Sweet potato thread 13 Pulling head 13a Fitting hole 13b Internal female thread 14 Traction locking hole

Claims

1. An OF cable traction fixture used when removing an existing OF cable, shaving off the outer skin such as the anticorrosion layer and shielding layer at the end of the OF cable to be pulled, exposing only a certain length of the conductor part in the center, covering the inner pipe around the outer periphery of the conductor part, and driving a wedge into the conductor part from the end face of the conductor part exposed at the tip opening of the inner pipe, covering the outer periphery of the inner pipe with a pulling outer pipe whose tip face is blocked, and screwing a screw that reaches the conductor part through the screw hole of the inner pipe from the screw hole on the outer periphery of the pulling outer pipe, a protruding body with an outer male thread is integrally provided on the tip outer surface of the pulling outer pipe, and a vulcanized rubber layer formed by winding a tape made of vulcanized rubber is formed on the outer peripheries of the pulling outer pipe and the outer skin of the OF cable adjacent thereto, The outer periphery of this vulcanized rubber layer is covered with a cylindrical cover, both ends of the cylindrical cover are fixed to the pulling outer pipe and the outer skin, and the protruding body is screwed and fitted into the fitting hole of a pulling head having a traction locking hole. OF cable traction fixture characterized by being.

2. The cross-sectional shape of the inner pipe is a shape with a part of the circular outer edge cut out, and the opening of the hollow part into which the inner pipe of the pulling outer pipe is fitted has the same shape as the cross-sectional shape of the inner pipe. After fitting the inner pipe into the hollow part of the pulling outer pipe, the pulling outer pipe is rotated around the axis, and part of the peripheral edge of the opening of the pulling outer pipe is locked to the end of the inner pipe, making it impossible to pull out the pulling outer pipe from the inner pipe. The OF cable traction fixture according to claim 1, characterized by having a configuration.

3. A small-diameter hole is provided from the tip end face of the protruding body to the hollow part containing the inner pipe of the pulling outer pipe, and a detachable sealing plug is provided at the tip of the small-diameter hole. The OF cable traction fixture according to claim 1 or 2, characterized by being.

4. The cylindrical cover is divided into two in the longitudinal direction. An external male thread is provided on the outer periphery of one divided edge, and an internal female thread is provided on the inner periphery of the other divided edge. The external male thread and the internal female thread are screwed together to be connected to one cylindrical cover. The traction jig for the OF cable according to claim 1 is characterized by this configuration.

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