JPH0342634Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field of the Invention) The present invention relates to a cable connection part forming apparatus with good workability, which is used when forming a cable connection part by injection molding.

(Technical background of the invention) Conventionally, as a method of forming a cable connection part by injection molding, a mold is fitted around the outer periphery of the conductor connection part of a cable that has been stripped in stages and conductor connections are made. A method is known in which a rubber or plastic composition heated and melted by a rubber or plastic extruder is press-fitted into a mold through piping into a cavity.

However, since such cable connection work is generally performed in a narrow space such as a manhole, it is necessary to use a cable connection forming device that allows heavy and difficult-to-handle equipment such as rubber or plastic extrusion machines to be installed outside the manhole. It is desired that the connection work be made easier.

However, in conventional cable connection forming devices, the total length of the piping that supplies rubber or plastic is usually limited to 2 m or less due to the relationship between its pressure resistance and the extrusion pressure of rubber and plastic.
The disadvantage of the plastic extruder was that it had to be carried into a manhole and installed near the mold. In other words, in order to install the rubber and plastic extrusion machine outside the manhole, the piping is made longer, and in order to smoothly press fit the rubber and plastic into the cavity, the pressure resistance of the piping is increased, and the rubber and plastic extrusion pressure is increased. However, the pressure resistance of the piping cannot be increased that much because it requires bending, and there is a limit to how high the extrusion pressure of rubber or plastic can be increased.

For this reason, the applicant first proposed a rubber and plastic extruder installed above ground near the manhole.
a mold for forming an insulator that is fitted around the outer periphery of the conductor connection part of a pair of cables to be connected in the manhole;
A pipe for supplying the rubber and plastic heated and melted from a plastic extruder to this mold, a heating device surrounding the outer periphery of this pipe, and a pipe connected to the middle of the pipe to transfer the molten rubber and plastic. We have proposed a cable connection forming device consisting of a transfer pump (Utility Application No. 173401/1983).

Incidentally, in such a cable connection forming device, an iron pipe or an aluminum pipe is generally used as the piping. However, when the piping is a metal pipe as described above, the shape of the piping is constant, so the placement of the mold, rubber, and plastic extruder must be constant, and part of the inner wall of the metal pipe is heated. There is a problem in that the extrusion pressure and high heat of the molten resin causes it to elute, and when it mixes with the heat-molten rubber or plastic, it adversely affects the electrical characteristics of the cable connection.

(Purpose of the invention) The present invention was made in response to the conventional circumstances, and is a cable that improves the workability of cable connection and prevents foreign substances such as metal from getting mixed in with heated and melted rubber and plastic. It is an object of the present invention to provide a connection forming device.

(Summary of the invention) The invention provides piping that connects a rubber or plastic extruder and a mold for forming an insulator with an inner layer made of polytetrafluoroethylene resin and having flexibility, and an outer layer of this inner layer. and a reinforcing braided layer provided on the piping, and a heater is provided on the piping.

(Embodiment of the invention) Hereinafter, an embodiment of the invention will be described in detail as shown in the drawings.

FIG. 2 is a diagram schematically showing a state in which a cable connection part forming apparatus according to an embodiment of the present invention is installed in a manhole where cable connection work is performed.

In FIG. 2, reference numeral 1 indicates a rubber/plastic extruder for forming cable connections installed in the above-ground area A near the manhole 2. If necessary, piping 5, 5, etc., which will be described later, supply heated and melted rubber or plastic to the split mold 4 for forming a molded insulator, which is fitted over the conductor connection portion of the pair of cables 3, 3. Transfer pumps 6, 6, . . . are connected and arranged in the middle. In addition, a band heater 7 is installed on the outer periphery of the pipes 5, 5...
The rubber that is wrapped around and passes through the pipe,
The band heater 7 maintains the plastic at a low viscosity for easy flow.

The pipes 5, 5 are, for example, 4 as shown in FIG.
A non-metallic flexible hose 8 made of fluorinated ethylene copolymer and a reinforcing braided layer 9 provided around the outer periphery of the hose 8
It is made up of.

The flexible hose is made of tetrafluoroethylene copolymer because the hose made of tetrafluoroethylene copolymer has heat resistance and can smoothly transfer heated and melted rubber and plastic. It is.
That is, this is because rubber and plastic resin have good sliding properties. The reinforcing braided layer 9 consists of double braids 10 and 11 of, for example, stainless steel wire, and a horizontally wound layer 12 of, for example, stainless steel wire is provided between these braids.

The purpose of providing the reinforcing braided layer 9 is to maintain the shape of the flexible hose 8 smoothly and to increase the pressure resistance of the hose.

In the cable connection forming apparatus configured as described above, the rubber and plastic extruded from the rubber and plastic extrusion port at a predetermined pressure from the rubber and plastic extruder 1 are transferred to the transfer pumps 6 and 6.
It is pressurized by... and is smoothly supplied into the split mold 4 through the inside of each piping 5, 5.... In this case, the amount of rubber and plastic extruded by the rubber and plastic extruder 1 and the amount of discharge from the transfer pumps 6, 6, . . . are adjusted to be approximately the same.

When a transfer pump is installed in the piping connecting the mold and the rubber or plastic extruder, the rubber or plastic extruder, which conventionally had to be carried in and installed inside the manhole, can be installed above ground near the manhole. Also, it can be press-fitted into rubber or plastic molds well, and workability in cable connection can be improved.

In addition, in the present invention, the location of the transfer pump is within the range where the rubber or plastic can be smoothly press-fitted into the mold.
It is determined by considering the plastic extrusion pressure, the discharge pressure of the transfer pump, and the pressure resistance strength of the piping. A gear pump is suitable as the transfer pump, but any pump can be used as long as it has a high discharge pressure and is capable of transferring high-temperature rubber or plastic.

(Effects of the invention) As explained above, according to the cable connection part forming apparatus according to the invention, the piping connecting the rubber or plastic extruder and the mold for forming an insulator can be
It is constructed with a flexible inner layer made of fluorinated ethylene resin and a reinforcing braided layer provided on the outside of this inner layer, so the arrangement of the extruder and mold can be varied within the reach of the piping. . In addition, since the inner layer of the piping is made of tetrafluoroethylene resin, it is possible to smoothly transfer heated and melted rubber and plastics.Furthermore, a reinforcing braided layer is provided on the outside of the inner layer, which increases the pressure resistance of the inner layer. can be strengthened.

In addition, since the inner layer of the piping is made of non-metallic material, it is possible to
There is no fear that a trace amount of metal may be mixed into the plastic, and a cable connection portion with good electrical characteristics can be provided.

Furthermore, by installing a heater in the pipe, it is possible to prevent the hardening of rubber and plastic passing through the pipe, and since the inner layer of the pipe is made of tetrafluoroethylene resin, which has good thermal conductivity, The heat from the heater can be efficiently transferred to rubber and plastic.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of piping constituting the cable connection forming device according to the present invention, and FIG. 2 is a diagram schematically showing the usage state of one embodiment of the present invention. . 1... Rubber, plastic extruder, 2... Manhole, 3... Cable, 4... Split mold, 5...
... Piping, 6 ... Transfer pump, 7 ... Band heater, 8 ... Flexible hose, 9 ... Reinforcement braided layer.

Claims (1)

[Scope of utility model registration request] A rubber/plastic extruder, a mold for forming an insulator that is fitted around the outer periphery of the conductor connection portion of a pair of cables to be connected, and the rubber/plastic heated and melted from the rubber/plastic extruder into this mold. In the cable connection forming device, the pipe includes a flexible inner layer made of tetrafluoroethylene resin and a reinforcing braided layer provided on the outside of the inner layer. 1. A cable connection part forming apparatus, characterized in that the pipe is provided with a heater.