JPH0477285B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an optical cable intermediate connection connector used for permanently connecting optical cables in series (splicing), and an optical cable intermediate connection method using the same. be.

<Prior Art> Conventionally, a wide variety of connectors for splicing the ends of optical cables in series have already been proposed, and some of them have been commercialized. However, in general, many removable connectors are used, and these connectors mechanically hold the optical cable's clad part with male and female connectors, and then connect the male and female connectors. This is what I did. The present invention relates to the former splicing type.

<Problem to be solved by the invention> In both types of conventional optical cable connection connectors, a gap is created between the optical cable to be connected and the connector that holds it, and it is difficult to maintain watertightness in the cladding part where the coating is peeled off. However, it is difficult to connect optical cables that are used outdoors where raindrops are present, or for signals in machines that use water, etc., and there is a problem in that watertightness cannot be guaranteed.

The present invention aims to solve these problems, and has a hole into which the sheathing of the optical cable itself can be inserted at the time of connection, and the cladding part from which the sheathing of the optical cable has been peeled is held by the hard sleeve itself. The present invention provides an intermediate connector for optical cables in which the resin tube that is in close contact with the sheathing part of the cable is reduced and deformed on the outside of the tube to form a watertight seal, and the watertightness of the connection part is not destroyed. This paper proposes an intermediate connection method for optical cables using this method.

<Means for Solving the Problems> The configuration of the connector in the present invention to achieve this object is shown in FIGS. 1 to 4 corresponding to the embodiments.
To explain using the drawings, the connector includes a sleeve 1 for connecting an optical cable, an intermediate small diameter portion 2a located on the sleeve 1 and in close contact with the sleeve 1, and an outer sheath on both sides in the axial direction that covers the exterior sheathing portion k of the optical cable K. The series of synthetic resin tubes 2 is made of a heat-shrinkable resin material, and has a heat-meltable resin material on its inner peripheral surface. The resin layer 3 is adhered, the connection sleeve 1 is made of a hard material, and both ends 1a, 1a are slightly flared.
The cylindrical wall 10 has a hole 11 whose inner diameter is approximately the same diameter as the outer diameter of the cladding portion C of the optical cable K from which the exterior sheathing portion k has been removed, and the intermediate small diameter portion 2a of the synthetic resin tube 2 is heat-shrinkable. The optical cable K is a small-diameter portion that is tightly attached to the connection sleeve 1 by diameter reduction, and a part of the hot-melt resin layer 3 melted by the heat during heat shrinkage is attached to the optical cable K,
The structure is such that lumps 3a, 3a and 3b, 3b are formed between the covering parts k, k of K and the tube 2 and on the covering parts k, k of optical cables K, K.

In addition, the method for connecting optical cables using this is as follows.
Insert the optical cables K, K to be connected from both axial ends of the connector, position the clad parts C, C abuttingly in the hole 11 of the cylindrical wall 10 of the connection sleeve 1, and insert the synthetic resin tube 2. Insert the outer sheathing parts k, k of the optical cables K, K into the large diameter portions 2b, 2b at both ends,
Thereafter, the entirety of the synthetic resin tube 2 or at least the large diameter portions 2b, 2b at both extended ends are heated to contract and deform, and the heat-melting resin layer 3 is heated.
are thermally melted to form coated parts k, k of optical cables K, K.
The resin layer 3 is brought into close contact with the top through the hot-melt resin layer 3, and a portion of the melted resin layer 3 remains between the tube 2 and the covering portions k, k of the optical cables K, K due to the contraction pressure of the tube 2. A part of the optical cables K, 3a and 3b leaks out to the inner and outer surfaces to form lumps 3a, 3a and 3b, 3b on the covering parts k, k of the optical cables K, K, respectively.

<Function> Since the present invention is constructed as described above, the sleeve 1 itself formed of a hard material holds the clad portions C, C from which the covering portions of both the optical cables K, K to be connected are removed, and A heat-shrinkable resin tube 2 further covers the entire upper outer periphery of the tube and comes into close contact with the covering portion of the optical cable, thereby ensuring watertightness.

<Examples> Examples of the present invention will be described below based on the drawings.

1 to 4 are diagrams showing a first embodiment of the present invention.

Optical cables generally have an optical fiber core C with a standard diameter of 125 μm made of low-loss quartz glass.
and Clad C, whose outer periphery is covered with nylon with a standard diameter of 0.8 mm or a resin material with an equivalent modulus of elasticity, to form a core wire, and this is covered with a black synthetic resin material mixed with carbon to prevent light loss. There is one in which a tension member made of fiber is further arranged around the outer periphery of the tension member, and another in which this is further covered with a second resin coating layer.

Although the optical cable K referred to in the present invention is shown as the former three-layer type in the drawings, it goes without saying that the latter type is also applicable.

In this embodiment, a copper cylindrical body is used, and the inner diameter of the hole 11 in the cylindrical wall 10 is approximately equal to the diameter of the cladding portion C of the optical cable K. The copper sleeve 1 is formed using a copper pipe, and both ends 1a, 1a are slightly flared. The external heat-shrinkable tube 2 that houses this tube is made of black colored nylon, and the entire inner surface is covered with a heat-melted layer 3 of polyamide material.
It is a double tube with a coating.
The double tube 2 is heated and shrunk only at its intermediate portion 2a to a small diameter, and is brought into close contact with the outer peripheral surface of the copper sleeve 1 as shown in FIG.

By doing so, the unshrinked large diameter portions 2b, 2b of the heat shrinkable tube 2 are formed on the outer side of both ends of the copper sleeve 1.

To use such a connector, first peel off the required length of the coating on the end of the optical cable K, take out the cladding part C, and insert the two optical cables K and K with finished ends as indicated by the arrows in Figures 1 and 2. As shown, the large diameter ends 2b, 2 of the tube 2, respectively.
Insert the copper sleeve 1 into the copper sleeve 1 from b, and insert the clad parts C and C into the holes 11 of the copper sleeve 1 as shown in FIG.
After this, as shown in FIG. The diameter portions 2b, 2b are heated with a heating device such as a hot gun, and the portions 2b', 2b' are contracted and deformed as shown in the figure.

As a result of this heating operation, the heat-meltable resin layers 3, 3, which had been adhesively formed on the inner surfaces of the shrinkage deformed parts 2b', 2b' of the heat-shrinkable tube 2, are melted, and due to the compressive pressure of the tube 2, the optical cables K, A part remains between the sheathing parts k, k and the tube 2, and a part flows out to the inner and outer surfaces and forms a lump 3 on the sheathing parts k, k of the optical cables K, K.
a, 3a and 3b, 3b are formed. In this way, the copper sleeve 1 located within the tube 2, the cladding portions C, C of the optical cable K, and their connection portions maintain a completely watertight state.

Also, since both ends 1a, 1a of the copper sleeve 1 are widened in a truss shape, the widened both ends 1 of the synthetic resin tube 2 and the hot-melt resin layer 3 are widened.
As shown in FIG. 4, the adjacent portions of a and 1a are formed in a mountain-like manner, and the copper sleeve 1 is sandwiched between these raised portions, thereby bonding the copper sleeve 1 and the synthetic resin tube 2. has been firmly achieved.

In the above embodiment, the entire circumference is formed on the outer circumferential surface of both sides of the butt-butting portion of the clad portions C and C, which are indicated by the reference numeral a in FIG. By applying pressure to deform the optical cable from the cladding part to the sleeve 1, the gap between the cladding part of the optical cable and the sleeve 1 can be brought close to zero, and the relative positional deviation of the core part can be minimized. .

In addition, the optical cables K and K mentioned in each of the above embodiments are
It is preferable that the abutting end surface a is bonded using a synthetic resin adhesive, an ultraviolet curing resin adhesive, etc. which are generally used for connecting end surfaces of this type of optical cable.

Further, by expanding both ends 1a, 1a of the sleeve 1 into a flap shape, it is possible to smoothly insert the optical cable K into the sleeve 1.

In addition to those shown in the above embodiments, the heat-shrinkable tube 2 and the heat-melting resin layer 3 referred to in the present invention may be a double layer of high-temperature nylon and low-melting nylon, and the heat-melting material used inside 3 may be a hot melt adhesive. In particular, a material with good adhesion to the coating material commonly used as the exterior material of the optical cable K is suitable.

Further, as the heat-shrinkable tube 2, a black thread that does not transmit light or has low transmittance is suitable.

Further, as the sleeve 1, in addition to copper, aluminum, etc., materials that can be compressed and deformed relatively easily, such as brass, lead, etc., are suitable. However, it may also be formed of a hard resin material or the like.

Although the embodiments considered to be representative of the present invention have been described above, the present invention is not necessarily limited to the means described in these embodiments. It can be implemented with appropriate modifications within the scope of achieving the purpose and having the following effects.

<Effects of the Invention> As is already clear from the above description, the present invention has the following advantages:
The sleeve that connects the clad part of the optical cable is covered with a covering tube, and this covering tube is formed using a heat-shrinkable resin material, and an adhesive layer is formed on the inner surface of the sleeve using a heat-melting resin material or a heat-sensitive adhesive resin material. Since both ends of the sleeve are formed so as to protrude outward, the heat-shrinkable tube is heated and shrunk to tightly fit onto the outer sheath of the optical cable, thereby reliably preventing the optical cable from separating in the axial direction. At the same time, the watertightness of the cladding part can be maintained reliably, so it can be used as a connector and connection method for outdoor cables and optical cables in humid areas. In particular, in the present invention, both ends 1a of the sleeve,
Since the sleeve 1a is expanded in a flat shape, the portions of the synthetic resin tube 2 and the heat-meltable resin layer 3 adjacent to both ends of the expanded sleeve are raised in a mountain shape, and there is a gap between these raised portions. Since the sleeve 1 is formed to be sandwiched, the sleeve and the synthetic resin tube can be reliably and firmly connected, and the clad part can be smoothly inserted into the sleeve 1. has advantages. In addition, a part of the heat-meltable resin layer melted by the heat during the heat shrinkage forms a lump 3a between the coating parts k, k of the optical cables K, K and the tube 2, as well as on the coating parts k, k of the optical cables K, K. , 3a and 3
b and 3b, it is possible to maintain the copper sleeve 1 located inside the tube 2, the clad portions C and C of the optical cable K, and their connection portions in a completely watertight state. Furthermore, since the connecting sleeve of the cladding part is made of a hard material, bending stress due to external pressure is not directly applied to the cladding part from which the outer covering has been peeled off, and the connection part is more reliably protected. It has the effect of allowing you to

[Brief explanation of drawings]

1 to 4 are diagrams showing a first embodiment of the present invention, in which FIG. 1 is an overall perspective view, and FIGS. 2 to 4 are central longitudinal views showing connection methods sequentially. It is a front view. In the figure, 1 is the sleeve, 1b is both sides, 2 is the tube, 2a is the middle small diameter part, 2b is the large diameter part, 3 is the hot melt resin layer, 10 is the cylinder wall, 11 is the hole, C is the clad part, and K is the optical cable, k is the outer covering part.

Claims (1)

[Claims] 1. A sleeve 1 for connecting an optical cable, and an intermediate small diameter portion 2 located on and in close contact with this sleeve 1.
a, and a series of synthetic resin tubes 2 consisting of large diameter portions 2b, 2b extending outward in the axial direction and covering the outer sheathing part k of the optical cable K, and this series of synthetic resin tubes 2 It is formed of a heat-shrinkable resin material, and a heat-melting resin layer 3 is adhered to its inner circumferential surface, and the connecting sleeve 1 is formed of a hard material, and both ends 1a, 1a thereof are slightly expanded in a ripple shape. The cylindrical wall 10 has a hole 11 whose inner diameter is approximately the same as the outer diameter of the cladding portion C of the optical cable K from which the outer sheathing portion k has been removed.
The intermediate small-diameter portion 2a of the synthetic resin tube 2 is a small-diameter portion that has been heat-shrinked, and is closely attached to the connection sleeve 1 by the diameter reduction, and is made of a hot-melt resin that is melted by the heat during the heat-shrinking process. Optical cables in which part of the layer 3 forms lumps 3a, 3a and 3b, 3b between the sheathing parts k, k of the optical cables K, K and the tube 2 and on the sheathing parts k, k of the optical cables K, K. Intermediate connector. 2. Using the optical cable intermediate connector according to claim 1, insert the optical cables K, K to be connected from both ends in the axial direction, and connect the connecting sleeve 1.
The cladding parts C and C are placed in the hole 11 of the cylinder wall 10 at
are positioned abutting each other, and the outer sheathing parts k, k of the optical cables K, K are inserted into the large diameter portions 2b, 2b at both ends of the synthetic resin tube 2, and then the entire synthetic resin tube 2 is inserted. Or at least the extended large diameter portions 2b, 2b
is heated and contracted and deformed, and the hot-melt resin layer 3 is thermally melted so that it is closely adhered to the coated portions k, k of the optical cables K, K via the hot-melt resin layer 3, and the molten resin layer Due to the shrinkage pressure of the tube 2, a part of 3 remains between the tube 2 and the sheathing parts k, k of the optical cables K, K, and a part flows out to the inner and outer surfaces and onto the sheathing parts k, k of the optical cables K, K. lump 3a,
3a and 3b, an intermediate connection method for optical cables formed with 3b.