JPS6067911A - Optical connector - Google Patents

Abstract

PURPOSE:To prevent an optical fiber from projecting out even if expanding and shrinking thermally by inserting the optical fiber fixedly into a plug up to a clad, and working part of the clad except this fixed part so that neither the thermal expanding nor contracting stress of the clad is applied to the optical fiber. CONSTITUTION:The clad 1 at one terminal of an optical fiber cord is removed to expose the optical fiber 2, a jacket 3, and ''Kevler'' fiber 6 all partially, and the plug 4 is fixed to this exposed part. This fixation is attained by fixing the optical fiber 2 and jacket 3 inserted into through holes 41 and 42 of the plug 4 and the ''Kevler'' fiber 6 inserted while folded by using an adhesive 5 and a ring 7. Further, a cut part 10 is provided to part of the clad 1 which is not fixed to the plug 4 to prevent the thermal expansion and shrinkage of the clad 1 from extending to the optical fiber 2, and when tensile force is applied to the optical fiber cord, all of it is concentrated on the ''Kevler'' fiber 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an optical connector having excellent tensile strength properties.

[Technical background of the invention]

Generally, an optical connector has a plug fixed to one end of an optical fiber cord, which is made by sequentially covering optical fibers with a jacket, a kegura, and an outer sheath, and tensile force resistance is an important mechanical property. Therefore, the optimal structure for optical fiber cords is to transfer all the tensile force to Kevlar, which has a tensile force resistance characteristic of tens of hours as a tension member, and not to apply force to other parts, especially the optical fiber itself. It is. For this reason, it is important to set the Kevlar in a tensioned state without letting it slack when installing the plug. Inside the outer sheath of the optical fiber cord, the tail is in a tensioned state, so if both the outer sheath and the outer sheath are attached to the plug, it will be the strongest against tensile forces.

However, since the outer sheath is generally made of PvC, it expands and contracts significantly due to internal strain in response to thermal changes in the outside air. This causes an expansion/contraction force, leading to an accident in which the optical fiber protrudes from the plug.

Accordingly, a conventional optical connector is constructed as shown in FIG. The Keppler 6 is set on the plug 4 and fixed to the plug 4 with a crimping ring 7. Note that FIG. 1 shows the main body of a conventional optical connector, and accessories are omitted. - [Problems with Background Art] In the conventional example described above, since the jacket 1 is separated from the plug 4, there is no fear that the optical fiber 2 will protrude from the end face of the plug 4 even if there is a thermal change. However, Keppra 6 has envelope 1
Because it was caulked with the material removed, it was difficult to caulk it in a stretched state, and its tensile strength properties varied widely and were unreliable.

[Purpose of the invention]

An object of the present invention is to provide an optical connector that has a simple structure, does not cause optical fibers to protrude even when there is thermal expansion/contraction stress on the outer jacket, and has excellent tensile strength characteristics.

[Summary of the invention]

In this invention, the outer sheath is inserted into the plug up to the outer sheath, the outer sheath and Kepra are fixed to the plug, and the thermal expansion and yield stress of the outer sheath is transferred to a part of the outer sheath except for the fixed portion. This is an optical connector that has been processed to prevent transmission of information to other people.

[Embodiments of the invention]

The optical connector of the present invention is constructed as shown in FIG.
The same parts as in the conventional example (FIG. 1) are given the same reference numerals.

That is, the optical connector of the present invention has a plug 4 fixed to one end of an optical fiber cord.

In this case, the optical fiber cord 9 is constructed by sequentially covering an optical fiber 2 consisting of a core, a jacket 3, a Kevlar 6, and a jacket 1. At one end of this optical fiber cord, the jacket 1 is removed as shown in the figure to expose a portion of the optical fiber 7, the jacket 3, and the Kevlar 6, and a plug 4 is fixed to this exposed portion. At this time, the plug 4 has a through hole along its axis, and this through hole consists of a small diameter through hole 41 and a large diameter through hole 42 from the tip side. Then, the optical fiber 2 and the cage 3 are inserted into the small diameter through hole 41. Further, the exposed Kevlar 6 is inserted into the large-diameter through hole 42 after being folded over the outer cover 1, and is fixed to the plug 4 by caulking with a caulking ring 7 provided on the plug 4. Further, a portion of the outer sheath 1 is provided with means for not transmitting the thermal expansion and contraction stress of the outer sheath 1 to the optical fiber 2. That is, in this embodiment, a cut point 1o is provided in a part of the outer cover 1 that is not fixed to the plug 4.

In order to increase the caulking strength, an axial crack may be provided in the plug 4 at the caulking location, or an adhesive may be used in combination.

〔Effect of the invention〕

According to the present invention, it is possible to obtain an optical connector having a simple structure, excellent tensile force resistance, and high I/'1 reliability without protrusion of the optical fiber 2.

That is, when crimping and fixing, the Kepra 6 is stretched (excluding the folded part, which is inside the outer sheath l), and when it is inserted into the folded lug 4, the large diameter of the Kebra 6 and the plug 4 must be tightened. This has the effect of eliminating even the slightest slack between the four holes. Therefore, when the optical fiber cord 1 is pulled, all the force is concentrated on the Kepra 6, and the tensile force resistance characteristics are greatly improved. Furthermore, since the outer sheath 1 is cut after caulking, the thermal expansion and contraction stress of the outer sheath 1 is not transmitted to the optical fiber 2, and as a result, there is no problem of the optical fiber 2 protruding, and reliability is significantly improved. .

Incidentally, FIG. 3 shows another embodiment of the present invention, in which a bellows-shaped buffer portion 8 is provided in the outer cover 1 without cutting the outer cover 1. This buffer portion 8 can be easily formed by heating a glossy loose iron and pressing it against the outer cover 1. Even in the case of this embodiment, the thermal expansion and contraction stress of the jacket 1 is alleviated by the buffer portion 8, and a highly reliable optical connector without protrusion of the optical fiber 2 can be obtained. Furthermore, in this embodiment, since the outer cover 1 is not cut, there are no defects such as the Keppler 6 being cut during cutting, and the manufacturing process is facilitated. Also, outer covering 1
When it is pulled, the cut surface of the jacket 1 does not come out, giving it an excellent appearance.

It goes without saying that the present invention is not limited to the above-mentioned embodiments, but may include various modifications without departing from the spirit of the invention. −

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional optical connector, FIG. 2 is a sectional view showing an optical connector according to an embodiment of the present invention, and FIG. 3 is a sectional view showing another embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Outer cover, 2... Optical fiber, 3... Jacket, 4... Plug, 5... Adhesive, 6... Kepra, 7... Caulking ring, 8... Buffer part, 2... Optical fiber cord, 10... Cutting point.

Claims (1)

[Scope of Claims] (1) In an optical connector in which a plug is fixed to one end of an optical 7-ip cord formed by sequentially covering an optical fiber with a jacket, Kevlar, and an outer sheath, the above-mentioned outer sheath and Kevlar are removed. The exposed part of the optical fiber and jacket and the subsequent part of the jacket are inserted and fixed into the plug, and the thermal expansion and contraction stress of the jacket is applied to the part of the jacket outside the plug to the optical fiber. An optical connector characterized by providing a means for preventing transmission. (2) The optical connector according to claim 1, wherein the means includes providing a cutting portion in a part of the outer cover. (3) The optical connector according to claim 1, wherein the means includes providing a bellows-shaped buffer portion in a part of the outer cover. According to the first aspect of the present invention, the plug is adhered to the plug.
Optical connector according to items 3 to 3. (5) The optical connector according to any one of claims 1 to 4, wherein the outer cover portion is fixed to the plug together with the inner kegura (by caulking or adhesive). (6) Claims 1 to 5, wherein the Kepplar is folded back onto the outer cover and inserted into the plug, and the folded Keppler and the outer cover are fixed inside the plug. optical connector.