JP3056966U - Electrofusion joints for optical fiber cable sheaths. - Google Patents

Abstract

(57) [Problem] To provide an electro-fusion joint that can be drawn into the outer tube without resistance even if there is a protrusion or a step in the outer tube for protecting the sheath, thereby shortening the joining work time. SOLUTION: The outer wall of both ends of a tubular electrofusion joint having an inner diameter slightly larger than the outer diameter of a sheath of an optical cable is gradually thinned from the center of the joint toward both ends. Characteristic electric fusion joint.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a tubular electro-fusion joint used for joining sheaths for optical cable passage. In particular, the present invention relates to an electro-fusion joint which can shorten the joining operation time and can be drawn into the outer tube without any trouble even if there is a projection or a step in the outer tube for protecting the sheath.

[0002]

[Prior art]

 Optical cable networks are being developed nationwide to promote the advanced information and telecommunications society.Efficient and fair use of public spaces, such as roads, rivers, and sewer pipes, for the installation of these optical cables Is planned. As shown in FIG. 2, the optical cable 3 is generally passed through the normal sheath 2, and is further housed in the outer tube 4 in units of 5 to 6 to be protected. The sheaths to be joined are joined at the ends of the sheaths, and the joints are covered with a tubular electric fusion joint made of thermoplastic resin, and the heating wire embedded in the joint resin and the heating wire The inside of the joint resin tube is melted by the heat generated by energization from the terminal pin for fusing and fused to the outer surface of the sheath, and then drawn into the outer tube 4.

[0003]

[Problems to be solved by the invention]

 In such a conventional fusion spliced joint, it is necessary to suppress the thermal expansion when melting the joint resin due to heat generated by energization, so that it is necessary to increase the thickness of the joint. The difference between the diameter of the joint and the outside diameter is large, and the end of the joint is usually angular. In addition, the electric fusion joint generally has a terminal pin projecting from the heating wire to the outside through the joint resin in order to supply current to the heating wire embedded in the joint resin. As described above, since the conventional electrofusion joint has projecting portions such as both ends of the joint and terminal pins as described above, when the sheath connected by this joint is drawn into the outer tube 4, the outer tube is used. At the four ends and the protrusions and steps in the outer tube, the thick ends and the projecting portions such as terminal pins protruding outward at the joint portion of the sheath tube are caught, and the work of wiring is interrupted. There were many things.

[0004] An object of the present invention is to provide an electro-fusion joint having no protrusion as described above. Another object of the present invention is to provide a thinner electrofusion joint than a conventional electrofusion joint.

[0005]

[Means for Solving the Problems]

 The present invention includes the following inventions. 1. A tubular electrofusion joint having an inner diameter slightly larger than the outer diameter of a sheath for optical cable passage, formed so as to gradually become thinner from a predetermined position on the center side of the joint toward both ends. An electric fusion joint characterized by the following. 2. The electrofusion joint has one end joined to a heating wire disposed inside the joint, and the other end has a removable terminal pin protruding outward from the joint side wall. 2. The electrofusion joint according to claim 1. 3. The electrofusion joint has a total length of 100 to 120 mm, a thickness of 5 to 6 mm at a central portion, an outer diameter of 70 to 72 mm, and a position 20 to 22 mm from both ends of the joint toward the center to both ends. 3. The electrofusion joint according to paragraph 1 or 2, characterized in that the joints are formed so as to be gradually thinner, and the thickness of the two front end portions is 2 mm or less.

[0006]

[Embodiment of the invention]

 The electrofusion joint of the present invention is a thin tube of a predetermined length, which is made of a thermoplastic resin and has a heating wire embedded therein. The electrofusion joint of the present invention is formed so as to be sharpened in a tapered shape to a wedge shape from the center portion of the tube toward both ends, and the step at the end is substantially eliminated. It is a tubular body having a shape.

The electric fusion joint of the present invention has one end connected to a heating wire embedded in a thermoplastic resin tube, and the other end protruding outside the thermoplastic resin tube side wall as a terminal connected to a power supply. The terminal pins are provided with a thermoplastic resin tube so that the thermoplastic resin tube can be easily pulled out and removed after the thermoplastic resin tube is covered and fixed by heat sealing over the sheath tube joint. It is buried inside.

[0008] As a material for forming the thermoplastic resin tube forming the electrofusion joint of the present invention, a resin such as polyethylene or polypropylene is used. The terminal pin embedded in the electric fusion joint of the present invention has one end joined to the heating wire embedded in the resin, and the other end is arranged so as to protrude outside the resin tube side wall. Aluminum or stainless steel is used.

In the electrofusion joint of the present invention, the thermoplastic resin pipe is formed to be thinner than the conventional thermoplastic resin pipe. Even if the thermoplastic resin tube of the present invention is formed to be thin, it is possible to suppress the thermal expansion of the resin tube body during heat fusion by energization because of the resin generated during heat fusion by energization. This is because the thermal expansion of the tube can be substantially prevented by tightening and fixing with a tubular band made of aluminum or steel over the outside of the thermoplastic resin tube.

[0010]

【Example】

 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing a state in which the butted portions of sheaths are covered with the electrofusion joint of the present invention, and FIG. It is sectional drawing which shows the state accommodated in 4. As shown in FIG. 2, the optical cable 3 is normally passed through the sheath 2 and is housed in the outer tube 4 with six of them as one unit and protected. Then, as shown in FIG. 1, the sheath 2 has the optical cable 3 housed therein and the ends of one sheath 2A and the other sheath 2B to be joined are abutted with each other. The joint side resin is covered with a thermoplastic resin electrofusion joint 1 having a covering length, and heated and melted by energization from a terminal pin 6 to a heating wire 5 embedded in the joint resin. It is fused and fixed.

The above-mentioned electrofusion joint 1 preferably has a thickness of about 5 to 6 mm, and a portion 7 of a constant distance (Y) of the outer wall portion from both end portions to the center direction is in the end direction. It is formed in a wedge-shaped or tapered shape so that the end becomes a sharp end. The tapered to wedge-shaped tip 7 near the end is preferably formed at a length of about 20 mm to 25 mm in the center from both ends, and the tip hardly feels any thickness. More preferably, it is formed as sharp as possible.

The terminal pin 6 is formed of an aluminum or stainless steel pin having a length of about 13 mm to 15 mm and a diameter of about 4 mm, and has a distal end connected to a heating wire embedded in a resin. The end is protruded out of the resin and is embedded in the resin so that the part can be gripped and pulled out by a suitable drawing tool such as pliers.

Next, a description will be given of a mounting process of the above-mentioned slightly thin electrofusion joint of the present invention. First, the joint resin pipe 1 having an inner diameter of 60 mm, a length of 120 mm, and a thickness of 5 to 6 mm at the center is started from a position 20 mm from the end of the joint resin tube 1, and is gradually thinned toward both ends. An electrofusion joint 1 made of polyethylene and having a thickness of 2 mm at the tip is prepared, and the electrofusion joint 1 is covered with a seam X between the optical cable sheaths 2A and 2B having an outer diameter of 60 mm. Deploy. Next, a steel tubular band (not shown) is wrapped around the outside of the electrofusion joint 1 and tightened and fixed. Next, a current is applied to the heating wire 5 from the terminal pin 6 to melt the resin on the inner surface side of the electrofusion joint 1, and the outer peripheral wall including the butted portion X of the sheaths 2 </ b> A and 2 </ b> B is bonded to the inner surface of the joint. Next, the terminal pin 6 is pinched with pliers and removed.

The sheath tube 2 having the butted portion adhered and fixed by the electrofusion joint obtained in this way can be connected to the outer tube 4 made of PVC or the like by a wire. In addition, since there are no large steps or protrusions at the seam of the sheath, there is no snagging in the outer tube or the end of the outer tube entrance, and the wire can be smoothly connected. In addition, since a steel tubular band is wrapped around the outer surface of the electrofusion joint and tightened and fixed to carry out current welding, the electrofusion joint itself does not expand even though it is relatively thin. Even after the steel band is removed after the heat fusion work, the swelling of the entire electric fusion joint is small, and there is almost no protrusion in the outer pipe and little catch on the end of the outer pipe mouth during the wiring work to the outer pipe .

[0015]

[Effect of the invention]

 According to the present invention, there was no step at both ends of the conventional fusion spliced joint and no projecting parts such as terminal pins. There was no delay.

[Brief description of the drawings]

FIG. 1 is an exploded cross-sectional view illustrating an electric fusion joint of the present invention.

FIG. 2 is a diagram showing a state in which a sheath containing an optical cable is passed through an outer tube.

[Explanation of symbols]

1: electric fusion joint, 2: sheath, 3: optical cable, 4:
Outer tube, 5: heating wire, 6: terminal pin, 7: joint end, X: butt tube butt, Y: joint end length.

Claims (3)

[Utility model registration claims] 1. A tubular electro-fusion joint having an inner diameter slightly larger than an outer diameter of a sheath of an optical cable, wherein the thickness is gradually reduced from a predetermined position on the center side of the joint toward both ends. An electro-fusion joint characterized by being formed in. 2. The fusion spliced joint is characterized in that one end is joined to a heating wire arranged inside the joint, and the other end has a removable terminal pin protruding outward from the joint side wall. The electrofusion joint according to claim 1, wherein 3. The electrofusion joint has a total length of 100-1.
20mm, center thickness 5-6mm, outer diameter 70-7
2 mm, is formed gradually thinner from the position of 20 to 22 mm from both ends of the joint toward the center toward both ends, and the thickness of both ends is 2 mm or less, The electrofusion joint according to claim 1 or 2.