JPH0577917B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a conductive rubber ring. More specifically, the present invention relates to a conductive rubber ring used for sealing the joints of underground pipes for protecting telephone cables.

[Prior Art] A power-carrying cable or an optical cable is placed inside an underground pipe for protecting telephone cables. These underground pipes are constructed to be electrically continuous to prevent inductive disturbances caused by external electric fields to the internal telephone cables. For this reason, cast iron pipes are generally used as the pipe bodies of buried pipes, and conductive rubber rings are inserted into the joints between the pipe bodies.

The joint portion and conductive ring of a conventional underground pipe will be explained based on FIGS. 6 to 8.

In FIGS. 6 and 7, 1 and 2 are buried pipes such as cast iron pipes, and 1a and 2a are joint portions of the respective buried pipes. A male joint part 2a is inserted into the female joint part 1a, and a conductive rubber ring 50 is inserted between the inner circumference of the joint part 1a and the outer circumference of the joint part 2a. In the figure, 4 is a stopper ring for preventing the buried pipe 2 from slipping out, and 5 is a seal ring for preventing water from entering from the end of the pipe.

As shown in FIG. 8, the rubber ring 50 has a conductive chip 51 made of a brass plate attached to a heel portion 52.
It has a structure in which a large number of adhesives are pasted over the outer circumferential surface and inner circumferential surface of.

Therefore, as shown in FIG. 7, when this rubber ring 50 is brought into close contact between the joint portion 1a and the joint portion 2a, the pipe body is sealed and the conductive chip 51 seals the buried pipe. An energizing path is formed between 1 and the buried pipe 2.

[Problems to be Solved by the Invention] However, with the conventional rubber ring 50, a large number of conductive chips 51 must be attached.
There is a problem in that it requires considerable time and effort to manufacture. In addition, when adhering the conductive chip 51 to the heel part 52, it is preferable to apply a primer treatment to the conductive chip 51, but it is extremely difficult to apply a primer treatment to the conductive chip 51, which is approximately 5 mm square in size, so There is a problem with the reliability of power.

In view of the above circumstances, the present invention aims to provide a highly reliable conductive rubber ring that is extremely easy to manufacture.

[Means for Solving the Problems] The conductive rubber ring of the present invention has a heel portion provided such that a braid layer formed by coarsely braiding continuous conductive wires appears on its outer and inner circumferential surfaces. , and a valve portion integrally and continuously formed with the heel portion.

Note that the blade layer is preferably provided so as to appear on the outer circumferential surface and the inner circumferential surface of the heel portion.

[Function] According to the present invention, since the blade layer communicates between the outer circumferential surface and the inner circumferential surface of the rubber ring, when the blade layer is inserted into the joint of the tube bodies, one tube body and the other tube body are connected. and can be electrically connected.

Moreover, in the present invention, since the blade layer used is a single piece, compared to the conventional example using a large number of conductive chips, the labor of pasting etc. can be completely eliminated, and the number of manufacturing steps can be significantly reduced.

[Example] Next, embodiments of the present invention will be described.

FIG. 1 is a perspective view of a conductive rubber ring A according to an embodiment of the present invention, FIGS. 2 and 3 are partial perspective views showing the outer circumferential surface and inner circumferential surface of the conductive rubber ring A, respectively, and FIG. An explanatory view showing the manufacturing process of the conductive rubber ring A, and FIG. 5 is a partial cross-sectional view showing the conductive rubber ring A inserted into the joint.

In FIG. 1, A is a conductive rubber ring, which is composed of a rubber ring 3 and a braid layer 13 formed by braiding conductive wires. The rubber ring 3 is composed of a heel portion 11 having a substantially L-shaped cross section and a valve portion 12 having a generally circular cross-section, as is generally the case with conductive rings for underground pipes. The blade layer 13 is integrally braided with, for example, brass wire, brass plated wire, stainless steel wire, etc., and is formed into a ring shape with a cross-sectional shape similar to the heel portion 11 of the rubber ring 3. As shown in FIGS. 2 and 3, it is embedded in the rubber ring 3 so that it appears on the outer circumferential surface 3a and inner circumferential surface 3b of the rubber ring 3.

The conductive rubber ring A is manufactured, for example, as shown in FIG. 4.

First, the heel part 11 of the rubber ring 3 and the valve 12
It is molded separately from (process,). There are no particular restrictions on the molding method used here, but
For example, extrusion molding, punching molding, etc. are used.

Next, a conductive wire is braided onto the heel portion 11 using an appropriate braiding machine (step). When the blade layer is installed in a buried pipe and compressed at the joint, it flexes together with the heel part 11 and exhibits sufficient sealing performance, and at the same time, accidents such as cutting do not occur, and the necessary amount of current can be secured. Any type of wire may be used, but for example, a wire braided with 12 pieces of brass wire with a diameter of 0.3 mm, a pitch of 38, and one or two wires is used.

Next, the heel portion 1 is provided with a blade layer 13.
1 and the valve part 12 are placed in the same mold and vulcanized and molded (step). The molded rubber ring 3 has a blade layer 13 floating on its heel portion 11. Note that a very thin rubber film may adhere to the surface, but it is best to remove it by lightly finishing it with paper.

Conductive rubber ring A obtained as above
Since the conductive wires of the blade layer 13 are exposed on the outer circumferential surface and the inner circumferential surface of the heel portion 11, the outer circumferential surface side and the inner circumferential surface side have conductivity.

FIG. 5 shows a state in which the conductive rubber ring A is assembled into the joint portions 1a and 2a of the buried pipes 1 and 2. The pipe bodies of the buried pipes 1 and 2 are cast iron pipes. In the assembled state, the rubber ring 3 is sandwiched between the inner circumferential surface of the joint portion 1a and the outer circumferential surface of the joint portion 2a, and is compressed so as to be deformed into a somewhat flattened state. A protrusion 6 is formed on one joint portion 1a, which fits into the recess of the heel portion 11 of the rubber ring 3 and is in direct contact with the blade layer 13. Of course, the blade layer on the inner peripheral surface side of the heel portion 11 (hidden in the figure) is brought into close contact with the outer peripheral surface of the joint portion 2a. Therefore, the buried pipe 1 and the buried pipe 2 are electrically connected via the blade layer 13. Note that 4 in the figure is a stopper ring similar to that shown in FIG. 7, which is inserted to prevent the buried pipe 2 from coming off. Also, 5 is a seal ring,
It is inserted to prevent water from entering from the end of the pipe and to prevent corrosion of the blade layer 13.

The manufacturing method and usage conditions of the conductive rubber ring A of the present invention have been explained above. Although the conductive rubber ring A of the present invention can be used in the same manner as conventional conductive rubber rings, In addition, the blade layer 13 can be formed simply by integrally molding the blade layer 13 without the need for complicated labor such as pasting a large number of conductive chips, so that the number of manufacturing steps can be significantly reduced. Further, since the blade layer 13 can maintain the flexibility of the rubber ring 3 well, the sealing performance of the rubber ring 3 is not hindered, and the rubber ring 3 itself is also reinforced by the blade layer 13 and its strength is improved. It has the following advantages. Furthermore, since the blade layer 13 has a large cross-sectional area as a current-carrying path, it has good electrical conductivity, and there is no fear that it will peel off like a conductive chip, so the reliability of the electrical conductivity can be increased.

[Effects of the Invention] The conductive rubber ring of the present invention is easy to manufacture, has high reliability, and has good electrical conductivity.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a conductive rubber ring A according to an embodiment of the present invention, Figs. 2 and 3 are partial perspective views showing the outer and inner circumferential surfaces of the conductive rubber ring A, respectively, and Fig. 4 is a perspective view of a conductive rubber ring A according to an embodiment of the present invention. An explanatory diagram showing the manufacturing process of the conductive rubber ring A, FIG. 5 is a partial cross-sectional view showing the conductive rubber ring A inserted into the joint, and FIG. 6 is a partially broken view showing the joint of an underground pipe. Front view, 7th
The figure is a partially enlarged sectional view of a joint portion into which a conventional conductive rubber ring is inserted, and FIG. 8 is a perspective view of the conventional conductive rubber ring. (Main symbols in the drawing), 1, 2: Underground pipe (cast iron pipe), 1a, 2a: Joint part, 3: Rubber ring,
11: Heel part, 12: Valve part, 13: Blade layer.

Claims (1)

[Claims] 1. A heel portion in which a braid layer formed by coarsely braiding continuous conductive wires is provided so as to appear on the outer peripheral surface and inner peripheral surface of the heel portion, and a blade layer formed integrally and continuously on the heel portion. A conductive rubber ring consisting of a valve part and a valve part. 2. The conductive rubber ring according to claim 1, wherein the conductive wire is a brass wire.