JPS6016046B2 - Method of forming electrical cable partition walls - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of forming a bulkhead in an electrical cable.

In electrical cables such as plastic sheathed cables, a room-temperature curing mixture is filled therein to form partition walls, which are used as moisture-proof dams, gas dams, or the like.

Conventionally, in order to form this type of partition wall, a molding machine is installed at the location where the partition wall is to be formed, a room-temperature curable mixture is injected into the molding machine, the mixture is allowed to naturally harden at room temperature, and the molding machine is removed after the mixture has hardened. The hardened mixture was covered with a plastic cable to serve as a protective cover for the partition wall. However, this method requires a long time to harden the mixture;
It takes a long time to complete the series of work up to the installation of the protective cover, the manufacturing efficiency of the partition wall is poor, and the adhesion of the room temperature curing mixture to the insulated core wire is not sufficient just by allowing it to cure naturally. There were cases where a gas path occurred along the insulated core wire.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for forming partition walls for electric cables, which can easily form partition walls with sufficient airtightness in a short period of time.

Embodiments of the present invention will be described in detail below with reference to FIGS. 1 to 4.

As shown in FIG. 1, the plastic sheathed cable 1 is made by stripping off a predetermined length of the sheath 2 at the bulkhead forming part to expose the insulated core wire 3, and filling the end of the sheath 2 with a sticky mixture. Stoppers 4a and 4b for the mixture to be filled are formed, and the distance between the insulated core wires is widened. Next, sheath 2
Spacers 5a and 5b are provided protruding from the outer periphery of the end portions. The spacers 5a, 5b can be formed by overlapping a suitable adhesive tape, the outer diameter of which corresponds to the inner diameter of the rigid sleeve 6. Next, as shown in FIG. 2, the hard sleeve 6 that has been passed through the cape loop in advance is pulled back so that it straddles the spacers 5a and 5b. cover.

As the hard sleeve 6, commercially available hard polyvinyl chloride pipes or aluminum pipes can be cut into appropriate lengths. In order to prevent the hard sleeve 6 from moving and to prevent the injection mixture from leaking, a pressure tape 7 is wrapped with adhesive tape or the like from both ends of the hard sleeve 6 to the spacers 5a and 5b.
Perform steps a and 7b. An injection hole 8 and an air vent hole 9 are formed in advance in the hard sleeve 6, and a cold-setting or thermosetting mixture is filled into the hard sleeve 6 through the injection hole 8 to form a partition wall 10. Examples of curable or thermosetting mixtures include epoxy mixtures, polyester mixtures, polyurethane mixtures, liquid polybutadiene rubber mixtures, polysulfide mixtures, silicone rubber mixtures, etc. Next, as shown in FIG. The shrinkable sleeve 13 is pulled back and placed so that both ends thereof protrude outward from the spacers 5a and 5b by an approximately equal length. A melt adhesive 14 is coated thereon.Next, before the filled mixture 10 is cured, as shown in FIG. The intermediate portion thereof is brought into close contact with the outer periphery of the hard sleeve 6, and the both ends thereof are brought into close contact with the outer periphery of the sheath 2, respectively.

At this time, the room-temperature curable or thermosetting mixture for forming the partition wall is heated through the heat-shrinkable sleeve 13 and the hard sleeve 6. When the mixture is heated for curing in this way, the viscosity decreases and becomes smooth, and the wettability with the insulated core wire 3 improves, resulting in good adhesion, and no gas path occurs. This becomes the partition wall 10. The hot-melt adhesive 14 on the inner surface of the heat-shrinkable sleeve 13 is fused to the sheath 2 by the heat generated when the heat-shrinkable sleeve 13 is shrunk. In addition, in order to bond the filling mixture and the insulated core wire, the surface of the insulated core wire may be coated with plastic that has good adhesion to the filling mixture, and the exposed portion of the insulated core wire may be covered with a plastic that has good adhesion to the filling mixture. Activation treatment may be performed by a method.

Furthermore, a metal-plastic laminate tape may be fused to the surface of the plastic sheath within the filling mixture with the metal side facing outward, or an activation treatment such as flame treatment may be applied to impart adhesion to the filling mixture. good. If such a treatment is applied to the surface of the plastic sheath, a heat shrinkable sleeve without hot melt adhesive can also be used.
The present invention is not limited to the illustrated embodiment, but can also be applied to the case where a partition wall is formed at a general cable connection part.

As explained above, in the present invention, since the heat that heat-shrinks the heat-shrinkable sleeve is used to heat the room-temperature curable or thermosetting mixture for forming the partition wall, the viscosity of the mixture is temporarily lowered and the wettability increases. is improved, adhesion is improved, and good partition walls without gas paths can be easily obtained.

Further, in this case, the protective cover can be installed before the filling mixture hardens, so that the manufacturing efficiency of the partition wall can be improved. Furthermore, since the outer periphery of the partition wall is surrounded by a hard sleeve and a heat-shrinkable sleeve, airtightness is improved and mechanical strength is also improved, which is very advantageous in practice. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 4 are cross-sectional explanatory views showing each step of the barrier rib forming method of the present invention.

Turtle...Plastic sheath cable, 2...Sheath, 6
...Hard sleeve, 10...Bulkhead, 13...
...Heat shrink sleeve.

Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A hard sleeve is placed over the part of the electric cable from which the sheath has been partially removed, the inside of the hard sleeve is filled with a room-temperature curing or thermosetting mixture, and the hard sleeve and the cable sheath portions on both sides of the hard sleeve are covered with heat-shrinkable sleeves. . A method for forming partition walls of an electric cable, characterized in that the heat-shrinkable sleeve is heated and shrunk before the mixture is cured.