JPH09303658A - Electric fusion-type branch joint - Google Patents

Abstract

(57) Abstract: To provide an electric fusion-type branch joint that can always be easily pierced without being influenced by the outside temperature. SOLUTION: A metal cutter 5, which is provided on a convex surface of a saddle portion 1 and has an external thread formed on an outer surface movable along a tube axis, is housed in the tube, and a branch tube 3 is provided on an outer surface thereof. In an electric fusion-type branch joint having a cylindrical tube 2 provided with a mechanism 4 capable of gas sealing via an O-ring 6 at its head, a metal cylinder having an internal thread formed inside the cylindrical tube 2. A pipe 7 is provided, and the metal cutter 5 is moved by a screw mechanism in the metal cylindrical pipe 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric fusion type joint made of a thermoplastic resin, and more particularly, to an electric fusion type branch joint used when a branch pipe is taken out from a resin pipe through which gas flows.

[0002]

2. Description of the Related Art An electric fusion type joint made of thermoplastic resin heats the outer surface of a resin gas pipe or the like to be connected to the inner surface of the joint by energizing a heating wire buried in the inner surface of the joint with a connector pin. The connection is made by fusing. In recent years, with the widespread use of resin pipes that are lightweight, have excellent corrosion resistance, and are flexible and have the characteristics of being strong against earthquakes, their demand is rapidly expanding.

There are various types of this electric fusion type joint, but there is an electric fusion type branch joint called a service q for taking out a branch pipe from a resin pipe through which gas is not stopped without stopping the gas. is there.

FIG. 2 shows an electric fusion splicing type branch joint which is generally used at present. In the figure, 1 is a saddle part, 2 is a cylindrical pipe, 3 is a branch pipe, 4 is a cap, 5 is a metal cutter,
6 represents an O-ring.

A cylindrical metal cutter 5 is housed in the pipe on the convex surface of the saddle portion 1, and the branch pipe 3 is provided on the outer surface thereof.
Is provided, and a cylindrical tube 2 having a cap 4 capable of gas sealing via an O-ring is provided on the head thereof.

The saddle portion 1, the cylindrical pipe 2 and the branch pipe 3 are integrally molded by injection molding, and the metal cutter 5 is housed in the cylindrical pipe 2 after the injection molding. A female screw is formed on the inner surface of the cylindrical pipe 2 and a male screw is formed on the outer surface of the metal cutter 5, so that the metal cutter 5 can move along the pipe axis in the cylindrical pipe 2 by a screw mechanism. Further, the cap 4 is often made of the same resin as the saddle portion 1 and the like.

This electric fusion splicing type branch joint is used as follows. First, an electric fusion splicing branch joint is fused to an existing resin pipe (hereinafter referred to as a main pipe) through which gas is communicated, and a pipe through which gas should pass through the branch pipe 3 of the electric fusion splicing branch joint is constructed. To do. Then, the metal cutter 5 is moved in the cylindrical tube 2 using an auxiliary tool for perforation to perforate the side surface of the original tube. After that, when the metal cutter 5 is pulled up to the vicinity of the head of the cylindrical pipe 2, the gas is circulated from the main pipe to the branch pipe 3. At this time, the outer surface of the metal cutter 5 and the inner surface of the cylindrical tube 2 are screw-fitted, but a small amount of gas leakage occurs. Therefore,
Gas leakage is completely prevented by gas-sealing the head of the cylindrical tube 2 with the cap 4 via the O-ring 6.

After the construction, the metal cutter 5 is left in the pipe of the cylindrical pipe 2, and the resin piece obtained by punching the original pipe is also left in the pipe of the cylindrical metal cutter 5. ing.

[0009]

However, since the thermal expansion coefficient of the resin forming the cylindrical tube is significantly larger than the thermal expansion coefficient of the metal forming the cutter, the following problems occur due to temperature fluctuations. That is, in winter when the temperature is low, the screw rotation of the cutter becomes extremely difficult due to the large shrinkage of the resin, and in the summer when the temperature is high, the screw is jumped due to the large expansion of the resin, and the cutter spins idle to pierce the main pipe. Becomes difficult.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an electric fusion-type branch joint which can always be easily perforated without being influenced by the outside temperature. .

[0011]

Means for Solving the Problems The above-mentioned problems are provided on a convex surface of a saddle part, and a metal cutter having a male screw formed on an outer surface movable along a tube axis is housed in the tube.
In an electric fusion splicing type branch joint having a branch pipe provided on its outer surface and having a mechanism capable of gas sealing through an O-ring at its head, an internal thread is formed on the inner surface of the cylindrical pipe. A metal-made cylindrical pipe is provided, and the movement of the metal-made cutter is performed by a screw mechanism in the metal-made cylindrical pipe.

If a metal cylinder having an internal thread formed on the inner surface is provided inside the cylindrical tube, the coefficient of thermal expansion is the same as that of the metal cutter (when the metal cylinder and the cutter are made of the same metal) or almost the same. Since the metal cylinder and the cutter are made of dissimilar metals, the expansion and contraction of the male screw part and the female screw part will occur at the same rate or almost the same rate even if the temperature fluctuates, making it difficult to rotate the cutter screw. There is no screw jumping, and it is always easy to drill.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows one embodiment of the electric fusion splicing type branch joint of the present invention. In the figure, 1 to 6 represent the same as 1 to 6 in FIG. 2, and 7 represents a metal cylinder having an internal thread formed on the inner surface.

When a metal cylinder 7 having an internal thread formed on the inner surface thereof is provided in the cylindrical tube 2, the cutter 5 moves while punching the original tube by fitting its external thread to the internal thread.
At this time, since the screw fitting portion is changed from the conventional resin / metal fitting to metal / metal fitting, the screw mechanism is not damaged even if expansion / contraction occurs due to temperature fluctuations.

The metallic cylinder provided inside the cylindrical tube may be made of the same kind of metal as the cutter or different kinds of metals, but it has the strength to withstand the contraction of the resin cylindrical tube. Further, it is necessary that the resin cylindrical tube has an outer diameter that does not come off from the resin cylindrical tube even when expanded.

[0016]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, it is possible to provide an electric fusion-type branch joint which can always be easily perforated without being influenced by the outside temperature.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of an electric fusion splicing type branch joint of the present invention.

FIG. 2 is a view showing a conventional general electric fusion splicing type branch joint.

[Explanation of symbols]

 1 Saddle part 2 Cylindrical pipe 3 Branch pipe 4 Cap 5 Cutter 6 O-ring 7 Metal cylinder with internal thread formed on the inner surface

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Naoshi Murata 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Inside Nihon Kokan Co., Ltd.

Claims (1)

[Claims] 1. A metal cutter, which is provided on a convex surface of a saddle part and has a male screw formed on an outer surface that is movable along the tube axis in the tube, and a branch tube is provided on an outer surface of the metal cutter. In an electric fusion-type branch joint having a cylindrical tube whose head is provided with a mechanism capable of gas sealing via an O-ring, a metallic cylindrical tube having an internal thread formed on an inner surface thereof is provided in the cylindrical tube, An electric fusion-welding type branch joint, wherein the cutter made of metal is moved by a screw mechanism in the metal cylindrical tube.