JPS5837955B2 - How to connect electrical cables - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of connecting electrical cables using a heat shrinkable sleeve.

2. Description of the Related Art A connection part of an electric cable is known in which a heat-shrinkable sleeve is placed over the sheath on both sides of the core connection part of the electric cable, and the sleeve is heat-shrinked to form a sealed structure.

When constructing such a connection, the heat-shrinkable sleeve not only contracts in the radial direction, but also in the longitudinal direction;
Due to the way it contracts, the length of the contact area between the sheath on both sides of the core connection part and both ends of the sleeve may not be constant, which is one reason for the reduction in the airtightness and mechanical strength of the connection part. was.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrical cable connection method that solves the above problems and provides a highly reliable connection.

Embodiments of the present invention will be described in detail below with reference to the drawings.

In the figure, 1 and 2 are plastic sheathed cables to be connected, and 3 is a connecting portion of the cores of the cables 1 and 2.

On the sheaths la and 2a in the vicinity of the core connection portion 3, spacers 4 and 5 made of multi-layered adhesive tape, for example, are provided, respectively.

Next, the core connection part 3 is covered with a hard sleeve 6, and both ends of the hard sleeve 6 are attached to the spacers 4 and 5 using adhesive tape or the like.
Fix it on top.

Next, the outer periphery of the hard sleeve 6 is covered with a heat shrink sleeve 7.

The heat-shrinkable sleeve I is arranged so that both ends thereof extend the same length from both ends of the hard sleeve 60 onto the sheath.

In this state, the center portion of the heat-shrinkable sleeve 7 is heated to shrink, and the center portion is brought into close contact with the hard sleeve 6 (see FIG. 2).

This fixes the heat shrink sleeve 7 onto the hard sleeve 6.

The heat-shrinking operation of the heat-shrinkable sleeve is performed by rotating a heat source such as a torch lamp around the heat-shrinkable sleeve 7.

Next, the heat-shrinkable sleeve 7 is heated sequentially from the center to one end. and deflate (see Figure 3).

FIG. 4 shows the state in which the heat shrinkage work on one side has been completed.

A similar operation is performed on the other side to complete the connection operation (see Fig. 5).

In addition, when heating and shrinking the heat-shrinkable sleeve 7 sequentially from the center to the ends, as shown in FIG.
It is desirable to heat the vicinity of the unshrinkable portion (the portion indicated by arrow A) of the variable diameter portion 7c between the unshrinkable portion a and the unshrinkable portion 7b.

In this way, the contraction rate in the longitudinal force direction of the heat-shrinkable sleeve can be reduced by the conventional method of heating the entire variable-diameter portion (in order to improve adhesion, the shrinkage rate of the variable-diameter portion 7b in the vicinity of the contracted portion ?a is relatively It gets heated a lot.

) is much smaller than The following table is an example of the experiment.

The length of the heat shrink sleeve used before shrinking is 500V.
It is ts.

As explained above, the present invention first heat-shrinks the center part of the heat-shrink sleeve to fix it on the hard sleeve placed over the core connection part, and then heats the heat-shrink sleeve sequentially from the center to the ends. Since the ends of the heat-shrinkable sleeves are shrink-fitted onto the sheath on both sides of the core connection, the lengths are equal on both sides, resulting in a reliable connection in terms of tightness and mechanical properties. be able to.

[Brief explanation of drawings]

1 to 4 are sectional views showing the process of the connection method of the present invention, and FIG. 5 is a front view of the connection portion obtained by the connection method of the present invention. 3... Core connection part, 6... Hard sleeve, las2
a...Sheath, 7...Heat shrink sleeve, 7a...
Shrunk part, 7b... unshrinked part, IC... variable diameter part,
A: Near the uncontracted part.

Claims (1)

[Claims] 1. A step of covering the core connection portion with a hard sleeve, a step of covering the outer periphery of the hard sleeve and the sheath near both ends with a heat-shrinkable sleeve, and heating and shrinking the center of the heat-shrinkable sleeve to form a hard sleeve. A method for connecting an electric cable, comprising the steps of bringing the heat-shrinkable sleeve into close contact with the hard sleeve and successively heating and shrinking the heat-shrinkable sleeve from the center to the ends to bring the heat-shrinkable sleeve into close contact with the hard sleeve and then onto the sheath. 2. A patent claim characterized in that when a heat-shrinkable sleeve is sequentially heated and shrunk from the center to the ends, the vicinity of the unshrinked portion of the variable diameter portion between the shrunk portion and the unshrunk portion is heated. A method for connecting an electric cable according to item 1.