JPS58335Y2 - Cable retention device - Google Patents

Description

[Detailed explanation of the idea] This invention relates to an improvement in a tie-down device for trunk cables.

Conventionally, a cable grip for wire extension as shown in FIGS. 3 and 4 has been used as a terminal anchoring device for a trunk cable with a low-voltage branch.

That is, this is the trunk cable joining cores 21a, 21b, 21c.
After aligning each end of the cable and covering it with a vinyl chloride resin cap 23 through putty tape 22 and completely sealing it with insulating tape 24, a protective tape 25 is wrapped around the surface of the cable sheath, and a cable grip 26 is attached on top of it. Furthermore, by tightly wrapping the bind wire 27 around the two lower parts of the grip, when the cable is allowed to hang down, tension is applied by its own weight, and the cable grip 26 stretches in the length direction and contracts in diameter to bind the cable. However, this method of cable detention has the following problems.

The first problem is that the longitudinal position of the tethered cable is difficult to determine.

In other words, the cable grip is tightened using the fact that it stretches in the length direction, so the cable grip must be pulled well in advance to tighten it before suspending the cable. In some cases, the cable grip extends after hanging the cable.

This means that when a power distribution main line with branch lines drawn out in advance is suspended from the shaft of a high-rise residential building, the position of the branch line will not match the position of each floor.

The second problem is that when the tension applied to the cable grip increases, the wires that make up the grip dig into the outer sheath or insulation of the power distribution main line to which it is tied, and the insulating tape wrapped around the end of the main line becomes and protective tape wrapping,
Furthermore, the vinyl cap may even slip off, making it impossible to confirm the safety of power distribution.

In addition, the phenomenon is further exacerbated by the softening of the outer cover and insulator due to heat cycles caused by energization.

The third problem is that today, due to the soaring prices of residential land, houses being built in the suburbs of cities tend to become more and more high-rise, and as a result, power distribution main lines are becoming thicker and longer, and the tension that is applied to the cable anchorage is increasing. is getting even bigger.

For this reason, administrative guidance has been issued to prevent tension from concentrating on the cable anchorage by installing intermediate support sections for cables every 6 m on the vertical trunk lines of high-rise buildings.

Despite these problems, today there is a strong desire to reduce construction costs, and there is also a desire to further reduce the cost of laying power distribution lines for high-rise residential buildings.

This invention solves these problems and can be accomplished in an extremely easy and short time, and will be described in detail below with reference to the drawings showing an example.

1a, lb, and 1c are trunk cables wrapped around their sheaths and whose types are clarified by tapes 2a, 2b, and 2c, respectively, 3 is a compression sleeve, 4 is an insulating layer, 5 is a protective layer, 6 is an insulating fixing plate, 7 is an insulating protection cover, and 8 is a hanging metal fitting.

That is, the ends of each main cable 1a, Ib, and Ic are exposed and each conductor 9 is fixed with a compression sleeve 3.

A bolt 10 integrally protrudes from one end of the compression sleeve 3, and is inserted from below into three holes 11 drilled in an insulating fixing plate 6 made of an insulating material, and then tightened with a nut 12 on the top surface.
Fixed by

Next, an insulating layer 4 is formed by wrapping a self-fusing tape or the like around the outer circumference of the compression sleeve 3 in which the conductor 9 is compressed and fixed, and a protective layer 5 is further formed around the outer circumference using a shrinkable tube of ethylene, propylene, rubber, etc. .

The fixing nuts 12 on the upper surface of the fixing plate 6 are protected from above with putty tape 13, and the whole is inserted into the insulation protection cover 7.

The insulating protection cover 7 has a lower end 7a open and a hanging fitting 8 inserted into the upper part, and the hanging fitting 8 is screwed into a threaded portion 14 formed in the center of the insulating fixing plate 6.

The cable retention device of the present invention having the above configuration will be compared with a conventional cable net type retention device, and a comparison of their various performances will be described below.

Embodiment 600V three-core twisted cross-linked polyethylene insulated Zenyl sheath cable (hereinafter referred to as triplex).

Conductor: 60m4. Insulator thickness: 1.5 mm, sheath thickness: 1.5 mm) Strip off each core sheath and insulator at the end, and attach an insulating fixing plate (material: steel, A: 30 m) to the conductor end as shown in Figure 5.
yz, B: 12m1φ, C: 5+! ! IIL, D: 45
mm, E: 18 mm φ, F: 10.6 mm φ), and the insulating fixing plate shown in Fig. 6 (Material: Kenko Electric Co., Ltd., product number R1610, FRP, a: 201 tLb)
:85m1φ, c:13mmφ, eye fitting diameter: 12mm)
As shown in Figure 1, putty tape was wrapped around the compression sleeve, a protective layer was formed on top of it with a heat-shrinkable tube mainly composed of ethylene propylene rubber, and the compression sleeve was attached to the insulating fixing plate. The cable retention device of the present invention was manufactured by applying putty tape to the top of the nut and covering it with a protective cover.

Conventional Example The ends of each core of each phase of a triplex of the same size as the embodiment of the present invention were cut off with an offset of about 50 mm, and a 3.0 mm thick vinyl molded by dipping was placed on the ends with putty tape. Cover each core with a cap and wrap each core with self-adhesive tape 1゜□, 13, --/I/
Wrap the cable 7.± to form a protective layer, and then apply the cable grip (A: 37111W,
B: 25mcd: 20?117, L: 450
mm, M: 16 mm) and bound it to two locations at the lower end of the cable grip with a 2.0 mmφ tin-plated annealed copper wire to produce a conventional cable retainer.

Next, in order to confirm the effects of this invention, the following six tests were conducted on the above embodiment and the conventional example.

Test 1 Processing time for the cable anchorage section Comparing the processing time for the cable anchorage section in the example and the conventional example, it took about 20 minutes for the example and about 40 minutes for the comparative example.

Test 2 Workability Five workers with different years of experience in cable laying work were asked to process the cable anchoring portions of the example and the conventional example.In the case of the example, there was no difference in processing time or characteristics of the cable anchoring portion. However, in the conventional example, variations occurred in both machining time characteristics.

Test 3 Tensile test The cable anchorage sections of the example and the conventional example were attached to an Amsura set horizontal tensile testing machine, and changes in the cable anchorage sections were examined at a loading rate of 1 ton per minute. On the other hand, in the conventional case, the wire of the cable grip digs into the protective layer formed by winding self-adhesive tape and adhesive vinyl tape, and the terminals of each phase (core) are cut into the protective layer. The treated tape windings and vinyl caps were falling off or deformed.

Test 4 Long-term suspension test We created two triplex terminals, one with the cable retention part of the example and the other with the cable retention part of the conventional example, and set them in an 11th-floor building. The tension is three times the own weight of the triplex, i.e. 265 kg.
As a result of testing the displacement of the cable in the longitudinal direction when the tension of The deviation increases with each passing day, and becomes stable after 30 days.

Furthermore, depending on the skill level of the operator, the initial deviation may become significantly large.

Test 5.6 Withstanding Voltage Test and Insulation Resistance Test After completing Test 4 (long-term suspension test), apply 15 KV for 1 minute to each cable anchorage section using the device shown in Figure 8 to check for insulation breakdown. , the insulation resistance was checked at 1000 m -, and then the applied voltage was increased until dielectric breakdown occurred. As a result, no abnormality was observed in both the test in which 15 KV was applied for 1 minute and the insulation resistance test, but no breakdown occurred. In the test, interphase breakdown occurred in the example when 26.5 KV was applied for 30 seconds, whereas breakdown occurred in the vinyl cap part of the conventional example when 12.5 KV was applied for 15 seconds. .

The withstand voltage test shown in FIG. 8 was conducted in accordance with JIS 3005 vinyl insulated wire test method (underwater withstand voltage test method).

The above test results are summarized in the following table.

This invention is as described above, and has the following effects.

(1) Work time can be reduced to one-third of the conventional time.

(2) Improved workability eliminates variations in the quality and characteristics of cable anchorage parts due to differences in the skill of workers.

(3) Since the strength of the anchoring portion has been significantly increased, it is possible to omit intermediate supports that were conventionally provided every 6 m.

(4) Since the cable does not shift after hanging, branch connections to each floor are made easier.

(5) Electrical characteristics are improved and the safety of power distribution is greatly improved, so it is of great industrial value.

[Brief explanation of the drawing]

The drawings show an example of this invention; Fig. 1 is a partially cutaway front view, Fig. 2 is a sectional view taken along line A-A in Fig. 1, and Fig. 3 is a front view of a conventional cable retaining section. , Fig. 4 is a front sectional view of the cable termination in Fig. 3, Fig. 5 is a partial sectional front view of a compression sleeve for testing the present invention, and Fig. 6 is an insulating fixation for testing the present invention. A partial cross-sectional view of the plate, Figure 7 is an explanatory diagram of a conventional cable grip, Figure 8 is a partial cross-sectional view of the plate.
The figure is an explanatory diagram of the withstand voltage test device. 1a, 1b, 1c-main cable, 2a
+2b, 2c... Color is tape, 3...
・Sleeve, 4... Insulating layer, 5... Protective layer, 6... Insulating fixing plate, 1... Protective cover 8...... Hanging bracket, 9... Conductor, 10... Bolt, 11... Hole, 12
...Natsuto, 13...Putty tape, 1
4...Screw part.

Claims (1)

[Scope of utility model registration request] After fixing the conductors at each end of the multiple trunk cables with compression sleeves, an insulating protective layer is provided around the conductors, and the threaded portion protruding from one end of each compression sleeve is inserted from below the insulating fixing plate. A cable anchoring device characterized in that the cable anchoring device is fixed with a nut or the like, and the entire cable is housed in an insulating protection cover with an open bottom end, and a hanging metal fitting engaged with the insulating fixing plate is made to protrude from the top of the insulating protection cover. .