JP3728358B2 - Cable connection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of connecting cable using heat shrinkable tubing which shrinks by being heated above the required temperature.
[0002]
[Prior art]
One application of the heat-shrinkable tube is, for example, covering a conductor connecting portion of a rubber / plastic insulated cable 1 whose cross section is shown in FIG. The insulated cable 1 has a structure in which an inner semiconductive layer 3, an insulator 4, and an outer semiconductive layer 5 are formed concentrically in order on the outside of a central conductor 2. In such a rubber / plastic insulated cable 1, when laying a long line, the cable length is restricted due to problems in manufacturing, transportation, and laying. is there.
[0003]
As shown in FIG. 9, for example, as shown in FIG. 9, the cables are connected at this site by removing the insulation coating from the ends of the two cables 1 and 1 to expose the conductor 2 and butting the respective end faces together. In this state, the conductor connection sleeve 6 is put on the outer circumferences of the two conductors 2 to compress the connection, and then the inner semiconductive layer 3 similar to the cable 1 is formed outside the conductor connection sleeve 6. As a method for this, a method of covering the semiconductive tube 7 for internal conduction or winding a non-crosslinked semiconductive tape to a predetermined thickness and heat-molding it is adopted. Rubber-based heat-shrinkable tubes are used for surface shaping.
[0004]
In addition, the inner conductive semiconductive tube 7 is wrapped with multiple insulating tapes made of an uncrosslinked thermoplastic resin to form an insulating layer 8 instead of the insulator 4 of the cable 1, and an external layer is provided outside the insulating layer 8. A semiconductive tube 9 for external use is used instead of the semiconductive layer 5 for use, and in this case as well as the semiconductive layer 3 for internal use, a rubber-based heat shrinkable tube for surface shaping is used. Has been.
[0005]
As mentioned above, heat shrinkable tubes used for covering conductor connection parts of rubber / plastic insulated cables are usually uniform in order to equalize the heat shrinkage rate in the circumferential direction with respect to the support of the cable or the like. It is formed in a cylindrical shape with a diameter.
[0006]
Also, when shrinking a heat shrinkable tube as described above, a method using a heater, burner, etc. is used. If the heating is mistaken, defects such as kogation and cracking may occur, and the original characteristics may not be exhibited. Therefore, as shown in FIG. 10, the spare heat shrink tube 11 having the same shape is fed in advance to the outer periphery of one cable 1 before connecting the cable so as to cope with the case where the shrinkage process of the heat shrink tube fails. It is out. That is, if only one tube 11 is used, if the heating is mistaken, the joint must be cut again and re-executed, so that one extra tube 11 is put on the outer periphery of the cable before connecting the cable. I have to.
[0007]
[Problems to be solved by the invention]
However, since the conventional heat-shrinkable tube is formed by expanding a tube made of a predetermined material into a required cylindrical shape having a uniform diameter, for example, a plurality of heat-shrinkable tubes are fed into the cable outer periphery to be loosely fitted. In this case, since the tubes are brought into contact with each other and arranged on the outer periphery of the cable, the work range is extended by the length of the tube. For this reason, it is difficult to work in a limited space such as a manhole, and the spare tube is sent deep into the cave, so that there is a disadvantage that workability is deteriorated in this respect as well.
[0008]
Also, since the tubes are packed one by one at the time of transportation, the storage efficiency is poor, and even if a plurality of tubes are packed at the same time, the tubes are simply packed in parallel or in series. As a result, improvement in storage efficiency cannot be expected, and there is a problem that the cost becomes high after all.
[0009]
This invention has been made in view of the above circumstances, aims at providing Hisage how to connect the cable using heat shrinkable tube excellent in etc. space efficiency.
[0010]
[Means for Solving the Problem and Action]
To achieve the above object, the present invention is configured to connect the front ends of the cable is covered by a heat shrinkable tube to shrink the diameter by the outer periphery of the connection portion, it is heated above Jo Tokoro temperature In the cable connection method, the heat-shrinkable tube is formed in a tapered shape having a diameter gradually increasing from one end to the other end, and the two heat-shrinkable tubes including the spare ones are connected to each other. Fit in the same direction in a nested manner, feed it over the outer periphery of one cable before being connected, and connect one heat-shrinkable tube after completing the connection between the ends of each cable In the case where the cables are moved to the outer peripheral side of the connecting portions and the moved heat shrinkable tube is heated and shrunk so that the cable connecting portions can be tightly covered, the remaining one is left. Is a method which is characterized in that the heat shrinkable tube was cut to remove from the cable, also use one of the heat shrinkable tube that remains in the case of failure in the adhesion coating of the connecting portions to the adhesion coating of the connecting portion .
[0011]
Therefore, according to this inventions, since the shape of the heat shrinkable tube is tapered, it is possible to adjust fitting a plurality of tubes nested, when arranging a plurality of tubes in the outer periphery of the cable, in the longitudinal direction The length of can be shortened compared with the past. That is, since the space required for accommodation can be reduced, space efficiency can be improved. Further in accordance with this, when put in advance on the outer periphery of the cable for connecting the cable, it is possible to shorten the length in the longitudinal direction, easy connection work also work space a narrow space It can be performed.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next , an embodiment of the present invention will be described with reference to the drawings .
[0015]
FIG. 1 shows a heat shrinkable tube 12 of the present invention. As shown in the figure, this heat-shrinkable tube 12 is formed in a tapered shape that is gradually expanded in diameter from one end to the other end, and as an example, a cross-linked polyethylene is adopted. Yes.
[0016]
Here, the reason why the heat-shrinkable tube 12 is made of cross-linked polyethylene is that the heat shrinkage rate and the maximum use temperature can be increased, and the heat resistance, chemical resistance, and cracking resistance are excellent.
[0017]
Further, the heat shrinkable tube 12 is adjusted by an appropriate means so that the diameter of the uniform diameter tube is gradually expanded from one end to the other end, that is, in a tapered shape. Is formed. Accordingly, since the cylindrical tube having a uniform diameter is formed by expanding, the contraction rate at both ends differs when heated and contracted, and finally, it acts to return to the uniform diameter before the expansion. . Further, by forming the taper shape, the plurality of heat shrinkable tubes 12 can be fitted in a nested manner as shown in FIG.
[0018]
As an example, an adhesive layer 13 is provided on the inner surface of the heat shrinkable tube 12. When the heat-shrinkable tube 12 is heated and shrinks, the adhesive layer 13 is in close contact with the outer periphery of a member serving as a support disposed in the heat-shrinkable tube 12 and melts due to heat generated by heating. The heat-shrinkable tube 12 and the support are brought into close contact with each other by the tightening force or pressing force on the support accompanying shrinkage, and when the temperature is lowered, the predetermined attachment portion is adhered in an airtight state. . In addition, as an adhesive agent employ | adopted for this contact bonding layer 13, the styrene-isoprene-styrene type thing is employ | adopted as an example.
[0019]
The material of the heat shrinkable tube 12 includes tensile strength, elongation rate, shrinkage rate, volume resistivity, dielectric breakdown strength, fusion tangent, etc., compatibility with the member to be the support, and the tube 12 and the support. The material may be selected in consideration of the temperature and pressure between them, for example, polyethylene-based ethylene-propylene copolymer (EPM), ethylene-propylene-diene terpolymer (EPDM), ethylene -In addition to vinyl acetate copolymer, vinyl-based, polyolefin-based, and silicon-based resin materials can be employed. Specifically, resin materials such as butyl rubber (IIR), polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polystyrene, polyester, and hydrochloric acid rubber can be employed.
[0020]
The adhesive used for the adhesive layer 13 on the inner peripheral surface of the tube 12 is appropriately selected depending on the chemical resistance, electrical reliability, heat softening resistance, etc. of the material of the tube 12, but is used. As the polymer, a polymer that melts at high temperature and has fluidity is good, and generally a block polymer is mainly used. Of these, the aforementioned styrene-isoprene-styrene is mainly employed. Other block polymers include styrene-butadiene-styrene, styrene-butylene-styrene, and ethylene vinyl acetate. In addition, styrene-isoprene block copolymers, styrene-ethylene are also used as hot-melt adhesives. -Adhesives such as butylene block copolymer, ethylene-vinyl acetate thermoplastic elastomer, butyl rubber and the like can be employed. Moreover, the adhesive layer 13 is not provided, but the commercially available adhesive of the type applied before covering on a support body can also be employ | adopted.
[0021]
When selecting an adhesive corresponding to the material of the tube 12, it is sufficient for material brushing (whitening phenomenon), crazing (cracking), cracking, cracking, deterioration due to migration of plasticizer, surface beveling, etc. It is preferable to choose carefully.
[0022]
In the case where airtightness, liquid tightness, etc. are not necessarily required between the outer peripheral surface of the member serving as the support and the inner peripheral surface of the tube 12, the adhesive layer 13 is provided on the inner peripheral surface of the heat shrinkable tube 12. It is not necessary to provide or apply an adhesive.
[0023]
Next, as an example, the heat-shrinkable tube 12 configured as described above is adopted as a covering member for the connecting portion 15 of the rubber / plastic insulated cable 14, and the operation in that case will be described.
[0024]
First, the two heat-shrinkable tubes 12 are fitted together in the axial direction, including the spare one. Then, the fitted heat shrinkable tube 12 is put on one of the cables 14 to be connected.
[0025]
Then, as shown in FIG. 3, after covering the heat-shrinkable tube 12 fitted to one cable 14, the ends of the cables 14 are connected by appropriate means. In this case, since the heat-shrinkable tubes 12 are fitted in a nested manner and arranged in a state in which the length in the longitudinal direction is shortened compared to the conventional one, there is no problem even if the space required for the connection work is narrow. Absent.
[0026]
Then, after connecting the cable 14, as shown in FIG. 4, one of the heat-shrinkable tubes 12 previously covered with one cable 14 is moved to a position where the entire connection portion 15 of the cable 14 is covered. In this state, the heat shrinkable tube 12 is heated by appropriate means such as a heater or a burner.
[0027]
In this case, since the heated heat-shrinkable tube 12 acts so as to return to the tube having a uniform diameter before the diameter is expanded, the tightening force on the cable 14 is the entire length in the longitudinal direction although it is tapered. And uniform. That is, since the heat-shrinkable tube 12 is obtained by expanding a tube having a uniform diameter, the heat-shrinkable tube 12 acts so as to return to the tube before diameter expansion. The tightening force with respect to does not change depending on its longitudinal direction.
[0028]
The heated heat-shrinkable tube 12 is gradually contracted in the circumferential direction so as to tightly adhere to the outer periphery of the connection portion 15 of the cable 14 and has substantially the same shape corresponding to the shape of the connection portion 15. Become. That is, the connection portion 15 is tightly covered with the heat shrinkable tube 12 (see FIG. 5).
[0029]
In this case, the adhesive layer 13 on the inner peripheral surface of the heat-shrinkable tube 12 is melted by heat at the time of heat-shrinking, and is pressed against the connection portion 15 by the shrinkage of the tube 12. The tube 12 is bonded to the tube 12 by the adhesive, thereby ensuring airtightness and liquid tightness between the tube 12 and the cable 14.
[0030]
If the connection portion 15 of the cable 14 can be sufficiently closely covered with the first heat-shrinkable tube 12, the heat-shrinkable tube 12 provided as a backup in case of failure becomes unnecessary. Cut and eliminate. In the case of failure, after removing the heat-shrinkable tube 12 that is incompletely adhered to the connecting portion 15, the spare heat-shrinkable tube 12 is moved to the connecting portion, and the covering operation of the connecting portion 15 similar to the above is performed. To do.
[0031]
Therefore, according to this heat-shrinkable tube 12, the tubes 12 can be nested together as shown in FIG. 3, so that the axial length thereof can be shortened compared to the conventional case. In the case of 14 mutual connection, as shown in FIG. 6, the connection work can be performed even in a small space.
[0032]
Further, in the case of transporting as shown in FIG. 7, the heat shrinkable tube 12 is formed in a tapered shape, so that it can be packed in the housing 16 in a state of being fitted in a nested manner, thereby improving transport efficiency. As a result, the conveyance cost can be reduced.
[0033]
Furthermore, when manufacturing a heat-shrinkable tube, usually, a predetermined diameter-expanding member is inserted into the tube, and the tube is pressed from the inside by the diameter expansion of the member to expand the diameter. According to the contraction tube 12, since it forms in a taper shape, the diameter expansion member inserted in the inside of a tube after tube shaping | molding can be easily extracted from the inside of a tube, and manufacturing workability | operativity can be improved.
[0035]
Further, in the above embodiment, cross-linked polyethylene was used as the material of the heat shrinkable tube 12, but is not limited thereto, tensile strength, elongation rate, shrinkage rate, volume resistivity, dielectric breakdown strength, fusion tangent, etc. Further, it can be selected from the materials described above in consideration of the compatibility with the cable 14 and the temperature and pressure between the tube 12 and the cable 14.
[0036]
Further, the adhesive used for the adhesive layer 13 on the inner peripheral surface of the tube 12 can be appropriately selected from the above-described adhesives and the like according to the tube material.
[0037]
In the above embodiment, the adhesive layer 13 is provided on the inner peripheral surface of the heat-shrinkable tube 12. However, if the connection portion of the cable 14 does not necessarily require airtightness, liquid tightness, etc., the adhesive layer 13 is used. Is not required.
[0038]
【The invention's effect】
As apparent from the above description, according to the inventions, when mounting in advance a plurality of tubes containing pre for connection to case b le to the cable, to reduce the length of its longitudinal direction Therefore, connection work or the like can be easily performed even in a place where the work space is narrow.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a heat shrinkable tube according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a state in which the heat shrinkable tube is fitted in a nested manner.
FIG. 3 is a cross-sectional view showing a state in which the heat-shrinkable tube is disposed on the outer periphery of a rubber / plastic insulation cable in a state where the heat-shrinkable tube is fitted in a nested manner.
FIG. 4 is a cross-sectional view showing a state in which one heat-shrinkable tube is moved to a position covering a connecting portion of a rubber / plastic insulation cable.
FIG. 5 is a cross-sectional view showing a state in which the heat-shrinkable tube is heated and is in close contact with the outer periphery of a connecting portion of a rubber / plastic insulation cable.
FIG. 6 is a cross-sectional view showing a state in which a rubber / plastic insulation cable previously covered with a plurality of heat-shrinkable tubes is connected in a small connection work space.
FIG. 7 is a schematic view showing a state in which a plurality of heat-shrinkable tubes are packed in a box for conveyance.
FIG. 8 is a cross-sectional view of a rubber / plastic insulated cable.
FIG. 9 is a cross-sectional view of a connecting portion between rubber and plastic insulated cables.
FIG. 10 is a cross-sectional view showing a state in which an example of a heat-shrinkable tube of a conventional invention is arranged on a rubber / plastic insulated cable.
[Explanation of symbols]
12 ... Heat-shrinkable tube, 13 ... Adhesive layer, 14 ... Rubber / plastic insulated cable, 15 ... Connection part.

Claims (1)

With connecting front ends of the cable, the connection method of a cable coated by thermal shrinkage tube of reduced diameter by the outer periphery of the connection portion, is heated above Jo Tokoro temperature,
The heat-shrinkable tube is formed in a taper shape with a diameter gradually increasing from one end to the other end, and the two heat-shrinkable tubes including the spare one are nested in the same direction. It is fitted to the outer peripheral side of one cable before being connected, and sent to the outer periphery of each cable, and after the connection between the end portions of each cable is completed, one heat shrink tube is connected to the outer periphery of the connection portion between the cables. The heat-shrinkable tube is heated and shrunk, and when the cable connection can be covered tightly, the remaining heat-shrinkable tube is cut and removed from the cable. A cable connection method comprising using one remaining heat shrinkable tube for the close contact coating of the connecting portion when the close contact covering of the connecting portion fails.

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