JPH0449606Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a multi-core optical fiber connector composed of a rectangular plug and an adapter that can interconnect multi-core optical fibers at once.

(Prior Art) Optical fiber connectors are connected by inserting plugs provided at the ends of two optical fibers into one adapter from both sides, and the necessary conditions are as follows.

Firstly, the plug and adapter should be easy to attach and detach, secondly, they should not be deformed even though they are small and thin, and thirdly, they should be stable against tension and bending, with low loss at the connection part and high fracture resistance. , is.

As an optical fiber connector that satisfies these conditions, the structure of Japanese Patent Application No. 60-25117, as shown in FIG. 2, has been proposed.

This optical fiber connector is composed of an adapter 2 having elastic claws 1 at both ends, and a plug 4 having an insertion guide 3. When the insertion guide 3 of the plug 4 is inserted into the adapter 2,
Each elastic pawl 1 engages in a groove 5 of the insertion guide 3, thereby connecting the optical paths of the optical fibers 6 on both sides. In addition, to remove the plug 4 from the adapter 2, pull the ejector 7 fitted on the outside of the insertion guide 3 to the right in the figure against the biasing force of the coil spring 8, and pull out the plug 4. .

Furthermore, the optical fiber 6 is held between the plug 4 by sandwiching the tensile strength fiber 9 between tapered holding members 10.
is connected to.

(Problems to be Solved by the Invention) However, although the above-mentioned optical fiber connector is effective for single-core optical fibers, it has a drawback that it cannot be directly applied to rectangular connectors for multi-core optical fibers.

That is, even if the portion other than the ferrule 11 is intended to be rectangular, since the coil spring 8 in the ejector is wound around the insertion guide 5, the outer circumferential surface of this portion must be circular. Therefore,
The cross-sectional dimensions of the connector become large, making it impossible to satisfy the demand for miniaturization.

Furthermore, since each claw 1 of the adapter 2 is formed by notching its outer circumferential surface in the axial direction, when a bending moment is applied to the end of the plug 4, the insertion guide 3 and ferrule 11 are bent, resulting in connection of the connector. The loss will be large.

FIG. 3 shows an example in which the adapter shown in FIG. 2 is made into a rectangular shape. If a notch 13 is made in the side surface of this adapter 12 to form a pawl 14 in the same manner as described above, and the upper and lower plate thicknesses t are made smaller in order to make it more compact, it will deform due to the bending moment of the plug as shown in Fig. 2. It becomes easier. Therefore, the connection state between the adapter 12 and the plug becomes unstable, making it unsuitable for use as a rectangular connector.

Further, the tensile strength fibers 9 (FIG. 2) are attached to the presser member 1.
Since it is held with a compressive force smaller than 0, the material is limited to polymer fibers that can be compressively deformed. For this reason, it is not possible to connect an optical fiber mounted with a tensile strength member such as a steel wire that has a large Young's modulus and is difficult to deform to the plug using the above-mentioned means.

Furthermore, although fibers exhibit considerable strength against tension in the axial direction, they have the disadvantage of being weak against shear strength.
Therefore, if the tensile strength fibers 9 are caught between the metal edge portions 15 as shown in FIG. 2, there is a risk that they will break if the required retention strength is less than 10 kgf.

(Purpose of the invention) The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a rectangular multi-core optical fiber connector that is compact, enables high-density mounting, and provides a stable connection state. With the goal.

(Means for Solving the Problems) In order to achieve the above object, the present invention is composed of a plug attached to the tip of a multi-core optical fiber cable and an adapter to which the plug can be connected detachably. The first sleeve is made of a rectangular tube-shaped first sleeve made of a flexible material, and a second sleeve made of a tough material and fitted around and fixed to the first sleeve.
The sleeve has claws deformably supported by two notches provided along the axial direction from the opening on a pair of opposing sides thereof, and a second
The sleeve has a pair of opposing inner surfaces thereof each having a recess that forms a relief corresponding to the deformation of the claw, and the plug has a ferrule that fixes the ends of the plurality of optical fibers, and at least the tip of the plug has a ferrule that fixes the ends of the plural optical fibers. an insertion guide that has a rectangular shape that can be inserted and fitted into the sleeve of No. 1 and that holds the ferrule; The insertion guide consists of a retaining member, a rectangular tube-shaped ejector that is attached around the insertion guide so as to be movable in the plug and adapter attachment/detachment direction, and a pair of coil springs. The ejector has grooves and recesses on its side surfaces that engage with the claws, and the ejector has recesses on its pair of opposing inner surfaces at portions corresponding to the recesses of the insertion guide. A multi-core optical fiber connector is proposed in which the pair of coil springs are inserted into the space formed by the recess so that the axial directions of the coil springs coincide with the directions of attachment and detachment of the plug and adapter.

(Function) According to the present invention, the bending moment acting on the plug is absorbed by the second sleeve, which is made of a strong material and is fitted and fixed around the first sleeve that has claws for connection. It is supported. In addition, a well-balanced force is applied to the ejector by the coil spring inserted into the space formed by the insertion guide and the recess of the ejector.

(Example) FIG. 1 shows a perspective view of a multi-core optical fiber connector according to the present invention, and FIGS. 4 and 5 show a horizontal sectional view and a vertical sectional side view of the connected state. .

This multi-core optical fiber connector is composed of a rectangular adapter 20 and a plug 21 of the same shape, and a similar plug 21 can be connected to the left side of the adapter 20, although not shown.

The adapter 20 is a flat prismatic sleeve 2.
2 and an exterior sleeve 23 that covers the outside thereof, and claws 25 that protrude inward through cuts 24 are formed on both sides of the sleeve 22. on the other hand,
Recesses 26 are formed on both inner surfaces of the exterior sleeve 23 to provide relief for the claws 25, and each claw 25 can deform outward within the range of the recesses 26. A tapered portion 25A is formed at the tip of the claw 25 so that the plug 21 can be easily inserted. In this embodiment, the sleeve 22 is made of unfilled flexible plastic, and the outer sleeve 23 is made of FRP (fiber reinforced plastic). Therefore, even if a bending moment or a pushing force is applied from the plug 21 to the sleeve 22, the exterior sleeve 23 will reliably support them. Therefore, even if the thickness t of the sleeve 22 is reduced, the connection state between the plug 21 and the adapter 20 is stabilized.

As shown in FIGS. 4 and 5, the plug 21 includes a ferrule 27, an insertion guide 28,
It is composed of a retaining member 29 and an ejector 30, and a multi-core optical fiber 32 in a cable 31 passes through the plug 21 and reaches the front surface of the ferrule 27.

The ferrule 27 has a flat rectangular shape as shown in FIG. 6, and has stepped portions 33 formed on the top and bottom. A plurality of optical fibers 32 are arranged and passed through the inside of the ferrule 27, and holes 34 are formed on both sides of the tip. Therefore, when half of the coupling pin is inserted into the hole 34 and the hole of the opposite ferrule (not shown) is inserted into the remaining half of the coupling pin 35, the optical axes of each optical fiber 32 are aligned.

Around the ferrule 27, there are stepped portions 3 on the upper and lower inner surfaces of the insertion guide 28, as shown in FIG.
6 (see FIG. 5) is formed. A retaining member 29 for retaining the cable 31 is connected to the rear end of the insertion guide 28, and a coil spring 37 is inserted between the retaining member 29 and the ferrule 27, as shown in FIG. has been done. Therefore, the ferrule 27 is urged forward by the coil spring 37, and the stepped portion 33 of the ferrule 27 is in contact with the stepped portion of the insertion guide 28 (see FIG. 5). This coil spring 37 is connected to the adapter 2
The plugs inserted from both sides of the plug are brought into close contact with each other by the pressing force.

The retaining member 29 is formed with a plurality of cavities 38, as can be seen in FIG. 4, and each cavity 38 communicates with the outside by a hole 39. On the other hand, a plurality of tensile strength steel wires 40 extending from the end surface of the cable 31 are connected to each hole 39.
It enters the cavity 38 through. After the tip of the high-strength steel wire 40 is inserted into the locking pipe 41 via an adhesive 42, the center portion thereof is caulked. Since the locking pipe 41 is larger than the hole 39, the high-strength steel wire 40 does not come out of the cavity 38 or the hole 39, and therefore the cable 31 is also firmly connected to the locking member 29.

On both sides of the insertion guide 28, there are claws 25 of the adapter 20, as shown in FIGS. 4 and 7.
A groove 43 and an elongated recess 44 are formed to engage with. A tapered portion 28A is formed at the tip of the insertion guide 28, and a stopper 4 is formed on the upper and lower surfaces.
5 is provided. Insertion guide 28
As shown in FIG. 8, a rectangular cylinder-shaped ejector 30 is slidably fitted on the outside of the cylindrical body.

On both inner surfaces of the ejector 30, there are elongated recesses 4 corresponding to the recesses 44 of the insertion guide 28.
6 is provided, and a coil spring 47 (FIG. 4) is inserted into the space formed by both the recesses 44 and 46. Further, as can be seen from FIG. 5, stepped portions 48 and 49 are formed on the upper and lower and both inner surfaces of the ejector 30. For this reason, the ejector 30 is urged forward (to the left in the figure) by the coil spring 47, but the stepped portion 48 is pressed against the insertion guide 28.
It comes into contact with the stopper 45 and stops at this position.

Insertion guide 28 and ejector 30
It is preferable to use FRP, which has high strength, for molding.

In the multi-fiber optical fiber connector of this embodiment configured as described above, the adapter 20 and the plug 21 are attached and detached as follows.

When the plug 21 is inserted into the adapter 20, first the tip tapered portion 28A of the insertion guide 28 and the tapered portion 25A of the claw 25 in FIG. 2 come into contact. Next, as shown in FIG. 9, the claw 25 rides outward, and at the same time, the tip of the claw 25 pushes the ejector 30 in the direction of the arrow to contract the coil spring 47.

Further, when the plug 21 is inserted into the adapter 20, the claw 25 is elastically fitted into the groove 43 of the insertion guide 28, as shown in FIG. Further, the tip of the ejector 30 protrudes to cover the outside of the pawl 25 due to the pressing force of the coil spring 47, and the stepped portion 49 collides with the tip of the pawl 25 and stops. Therefore, claw 25
is locked by the tip of the ejector 30 and the stepped portion 49 without coming off.

A plug is inserted in exactly the same way on the opposite side (left side) of the adapter 20, thereby connecting the optical paths of the optical fibers 32 on both sides.

Next, when removing the plug 21 from the adapter 20, slide the ejector 30 backward.
The tip of the ejector releases the lock of the pawl 25, and when the plug 21 is further pulled, it expands outward again and the pawl 25 is completely removed from the insertion guide 28.

In this way, the ejector 30 locks and releases the pawl 25 automatically by the pressing force of the coil springs 47 inserted on both sides of the plug 21. Since the pressing force of each coil spring 47 acts simultaneously on each pawl 25, the ejector 30 always slides parallel and smoothly to the outer surface of the insertion guide 28.

Further, since a portion of the ejector 30 and the insertion guide 28 are hollowed out to house the coil springs 47, there is no problem even if the insertion guide 28 has a rectangular cross section. This coil spring 47 can be inserted at the same time as the ejector 30 is assembled to the insertion guide 28. The ejector 30 is prevented from coming off rearward by a coil spring 47, and the ejector 30 is prevented from coming off forward by a stepped portion 48 and a stopper 45.

Next, the assembly of the tensile strength steel wire 40 fixing the cable 31 to the rear end of the plug 21 and the retaining member 29 will be explained.

When the tensile strength steel wire 40 was made of stainless steel with a diameter of 0.7 mm, the locking pipe 41 was made of stainless steel with an inner diameter of 1 mm, an outer diameter of 2 mm, and a length of 4 mm, and an epoxy adhesive was used as the adhesive 42, one steel The retaining capacity of one caulked portion per line was approximately 20 kgf.

In addition, in the case of only the adhesive 42, approximately 10 kgf,
In case of caulking only, it is about 7Kgf,
It can be seen that the above configuration greatly improves the retention ability.

In Fig. 4, since two tensile strength steel wires 40 are used, the retaining capacity is approximately 40 kgf, but if the retaining member 29 is made of plastic, its material strength is considered to be sufficient at 20 kgf. There is.
Therefore, if the adhesive 42 can be cured for about one hour, the high-tensile steel wire 40 and the locking pipe 41
If only the adhesive 42 is used for the connection, and sufficient curing time is not available, caulking means may be used in combination, and if adhesive 42 cannot be used at all, caulking means alone may be used.

The above-described retaining means can be applied not only to the high-strength steel wire 40 but also to fibers. In this case,
After the tensile strength fibers are inserted into the locking pipe 41, the fibers are impregnated with the adhesive 42, and the locking pipe 41 is caulked before the adhesive 42 hardens.

Even with this configuration, unlike conventional products, the metal edges (see Figure 2) do not bite into the fibers, so a retaining strength of 10 Kgf or more can be obtained, and by using the retaining pipe 41. Costs are also reduced.

The five-core optical fiber connector realized in this embodiment has an adapter 20 with a width of about 13 mm, a thickness of about 8 mm,
Length: approx. 20mm, width of plug 21: 12mm, thickness: approx. 7mm
It is quite small, measuring approximately 43mm in length.

The conventional single-fiber optical fiber connector shown in Figure 2 has a plug diameter of approximately 8 mm and a length of approximately 40 mm.Comparing the cross-sectional area per fiber, this example has a plug diameter of approximately 8 mm and a length of approximately 40 mm. )/5 (center) = 16.8 (mm/center),
For conventional products, 4 x 4 x π (mm)/1 (center) = 50.3
It can be seen that the size can be reduced to less than 1/3 (mm/core). This is achieved by simplifying the storage area for the coil spring 47 that presses the ejector 30 and reducing the width of the plug 21, by providing an exterior sleeve 23 to reduce the wall thickness of the top and bottom surfaces of the adapter 20, and by making the adapter 20 sufficiently compact despite its small size. This is due to the use of a fastening means that provides strength. Two five-core optical fiber connectors according to the above example were made, and ferrule 27
When we measured the splice loss with a refractive index matching agent applied to the end face of the
It was as small as 0.2dB. This is equal to the connection loss between five-core connector ferrules, indicating that there is no increase in loss due to assembly into a connector. Therefore, the structure of the plug 21 and adapter 20 according to the present invention can be said to be ideal.

In addition, the connector and cable 3 in the connected state
When the outer covering portion of No. 1 was grasped and the tensile strength was measured, it was confirmed that it could withstand 10 kgf. Furthermore,
When the adapter 20 was fixed and a bending load was applied to the retaining member 29 of the plug 21, it was confirmed that the connection characteristics did not change even under a load of 5 kgf.

(Effects of the invention) As explained above, according to the invention, the second sleeve made of a tough material is fitted and fixed around the first sleeve having claws for connection with the plug. In this way, the bending moment acting on the plug can be supported by the second sleeve, resulting in a stable connection. In addition, by inserting a coil spring into the space formed by a pair of opposing recesses on the outer surface of the insertion guide and a pair of opposing recesses on the inner surface of the ejector, the cross-sectional shape of the insertion guide can be changed. A well-balanced biasing force against the ejector can be achieved regardless of the situation, and compactness and high-density mounting are possible.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an adapter and plug according to the present invention, Fig. 2 is a vertical sectional view showing a conventional connector, Fig. 3 is a perspective view of a conventional adapter, and Fig. 4 is a perspective view of a conventional connector. Figure 5 is a horizontal cross-sectional view showing the optical fiber connector, Figure 5 is a vertical side view, Figure 6 is a perspective view of the ferrule and optical fiber, Figure 7 is a perspective view of the insertion guide, and Figure 8 is a partial cutaway of the ejector. The cutaway perspective view and FIG. 9 are partial sectional views showing the fitting process of the plug and adapter. 20...adapter, 21...plug, 23...
Exterior sleeve, 25... claw, 28... insertion guide, 29... retaining member, 30... ejector, 31... cable, 32... optical fiber, 40... tensile strength steel wire, 43... groove, 44,4
6... recess, 47... coil spring.

Claims (1)

[Claim for Utility Model Registration] Consists of a plug attached to the tip of a multi-core optical fiber cable and an adapter to which the plug can be detachably connected, and the adapter has a rectangular tube shape made of a flexible material. and a second sleeve formed of a strong material and fitted and fixed around the first sleeve, the first sleeve having openings on a pair of opposing sides thereof. The second sleeve has a pawl that is deformably supported by two notches provided along the axial direction, and the second sleeve forms a recess corresponding to the deformation of the pawl on the pair of opposing inner surfaces thereof. The plug has a ferrule that fixes the ends of the plurality of optical fibers, and an insert that has a rectangular shape that can be inserted and fitted into the first sleeve and that holds the ferrule. a retaining member attached to the rear end of the insertion guide and retaining the multi-fiber optical fiber cable via its tensile strength member; and a retaining member that is movable around the insertion guide in the direction of attaching and detaching the plug and adapter. The ejector is made up of a rectangular tube-shaped ejector that is attached to the insertion guide, and a pair of coil springs. have recesses on the inner surface of the insertion guide at a portion opposite to the recess of the insertion guide, and the pair of coil springs are placed in a space formed by the recesses of the insertion guide and the ejector so that the axial direction thereof is the plug and the adapter. 1. A multi-core optical fiber connector, characterized in that each fiber is inserted in the same direction as the connecting and disconnecting direction of the optical fiber connector.