JPS59149704A - Method of preventing sheath from shortening at terminal of power cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for preventing shrinkage of a plastic sheath such as a polyethylene sheath or a vinyl chloride sheath at the terminal end of an electric cable.

[Prior art and problems]

Among electric cables, the sheaths of Cv cables (crosslinked polyethylene insulated vinyl sheathed cables) and O and E cables (crosslinked polyethylene insulated polyethylene sheathed cables) may shrink due to actual energization history. Therefore, as a method for preventing shrinkage, as shown in FIG.

(2) As shown in Fig. 2, insert the bracket 3 with the claw 3a into the sheath 1 and fix the bracket.

(3) As shown in Figure 3, adhere the sheath piece 4 etc. to the sheath 1 using a solvent or welding using a homogeneous material (4)
As shown in FIG. 4, the sheath piece 4 and the like are fixed with a shrinkable tube 5.

etc.

For OV cables, all of the above (1) to (4) can be used. However, in the case of OE cables, the sheath is made of polyethylene, so +11 and +21 have low tensile strength because polyethylene is hard, and +31 and +a+ have low adhesive strength and are difficult to use.

In short, in the case of a polyethylene sheath, (a) the polyethylene sheath is hard and the binding wires, claws, etc. are difficult to dig into, so the tensile force for the above il+ and (21) is small.

(b) Since it is made of polyethylene, there is no solvent suitable for the purpose, so method (3) cannot be adopted (for pollution and human safety reasons).

(c) Since there is no good welding agent, the welding method (31) has low adhesive strength.

) Since the existing cable terminals have already been processed,
Since the shrinkable tube cannot be inserted, it cannot be attached to an existing cable using method (4).

There are other problems.

[Structure and embodiments of the invention]

The present invention is concerned with the above-mentioned problem, particularly in improving the welding method (3).The present invention is characterized in that a notch is provided in a plate-like piece or a sheath piece made of the same material as the sheath, and welding is performed.

Embodiments of the present invention will be illustrated and described.

ill Cut out a sheath piece from the cable sheath as shown in Figure 5 (a) (it may be another plate made of the same material as the sheath).

(2) Provide an appropriate number of notches on the -F end side in Figure 5 (a).

(B) and (C) show examples of the notch 6.

(3) Next, remove the cable sheath and use a hot iron to fuse the sheath and sheath pieces together. You may also use a welding rod made of the same material as the sheath to apply the welding material. The parts to be fused are shown in Figure 6, with (a) being the front side and (b) being the back side.

(4) Set the cable sheath piece 4 so that it is caught on a fixed part such as the bracket 7, and stop the sheath from shrinking. Note that the arrow indicates the direction of sheath contraction.

〔Effect of the invention〕

The effect of the present invention is that by simply providing a notch in a plate piece or sheath piece made of the same material as the sheath and welding that part,
A major effect is that the tension was strengthened. It goes without saying that this method can be applied not only to polyethylene sheaths but also to plastic sheaths such as vinyl chloride sheaths.

[Brief explanation of drawings]

FIGS. 1 to 4 are explanatory diagrams of different conventional methods for preventing sheath contraction, and FIGS. 5 and 6 relate to the method of the present invention, and FIG. 5 (A) shows a sheath piece. (b) and (c) are explanatory diagrams with notches in (a), No. 6
Figure). (B) is a diagram showing a sheath piece with a notch attached to the sheath, showing the front and back sides, respectively, and (C) is a diagram showing the sheath piece with a notch attached so as to be attached to the fixed part of the bracket. It is an explanatory diagram. 1... Cable sheath, 2... Bind wire, 3...
・Bracket with claw 3a, 4...sheath piece, 5...
- Shrinkable tube, 6...notch, 7...bracket. Yellow 1 Figure Direction 2 Direction 3 Direction 4 Direction 5 Flash Direction 60

Claims (1)

[Claims] 1. In order to prevent the plastic sheath of the power cable, such as polyethylene or vinyl chloride, from shrinking at the end of the cable after the cable is laid, a plate-like piece or sheath piece made of the same material as the above-mentioned sheath is heated with a hot metal iron. A method of heat-sealing the cable to the cable sheath, or by melting a welding material made of the same material as the sheath and plate at high temperature and welding it to the cable sheath, and preventing shrinkage through fixing fittings such as brackets. The method is characterized in that a notch is provided in the plate-like piece or sheath piece, the length of the heat-fused or welded part is increased, the area is increased, the strength is reinforced, and the part is made to withstand shrinkage force. A method for preventing sheath shrinkage at the terminal end of an electric cable after installation.