JPH06250047A - Pressure tight optical connector - Google Patents

Abstract

PURPOSE:To provide a pressure tight optical connector with the small loss of an optical signal in a coupling part and capable of resisting to high-pressure and high-temperature gas. CONSTITUTION:An optical relay adaptor 13 is screwed on the jackplate 1 of a monitoring camera through a hermetic packing 11. An optical connector 7 is composed of a ferrule 7c, spring 7d, etc., protecting the tip part of an optical fiber 5a and is fastened to the optical relay adaptor 13 by means of a connecting nut 7a. An optical connector 10 is screwed from the other side of an optical relay adaptor 14 through a connecting nut 10a. A hermetic spacer 12 is mounted on the jackplate 1. A tube 15 is inserted into a holder 14 and the outer periphery of the hermetic spacer 12, is thermally shrunck and the optical fiber 5a is held and hermetically sealed by means of a bushing 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure resistant optical connector used in a surveillance camera.

[0002]

2. Description of the Related Art A special surveillance camera is used to take a picture of a jetting state when a rocket is launched. This camera is installed near the rocket launch pad and is connected to the control center by a fiber optic cable. In order to protect electric parts inside the camera from high-temperature and high-pressure exhaust gas immediately after the rocket is launched, nitrogen gas of, for example, 2 atm is enclosed in the camera. By increasing the internal pressure in this way, exhaust gas generated when the rocket is launched is prevented from entering the camera.

As described above, the surveillance camera is required to have a completely sealed structure. For this reason, conventionally, an airtight type optical adapter is attached to the jack plate, and a commercially available optical connector is connected to the optical adapter.

FIG. 4 is a sectional view showing the structure of an optical connector used in a conventional surveillance camera. In this figure, the jack plate 1 constitutes a part of the housing of the surveillance camera body, and various connectors are attached thereto. Here, the jack plate 1 is provided with a circular recess, and the optical relay adapter 2 is mounted therein. The optical relay adapter 2 is a cylindrical member, has a flange portion that comes into contact with the jack plate 1, an annular groove is provided on the outer peripheral portion thereof, and the O-ring 3 is inserted therein. When the optical relay adapter 2 is screwed to the jack plate 1, the O-ring 3 ensures airtightness between the left side space A inside the camera and the right side space B outside the camera. An opening is provided in the center of the optical relay adapter 2 for inserting an optical cable described later, and a screw portion is formed on the outer peripheral side surface of the opening.
The threaded portion meshes with the connection nut of the optical cable.

The holding portion 4 is a pair of cylindrical holding metal fittings inserted into the central opening of the optical relay adapter 2, and guides the connecting portion so that the joint surfaces of the optical cable 5 abut each other, and also the optical fiber 5a. It ensures the coaxiality. The holding part 4 is divided into two blocks on the left and right, and a glass 6 is held between them. The glass 6 is in contact with the end faces of the left and right optical fibers 5a to ensure the airtightness of the spaces A and B, and to reduce the reflection loss of light on both end faces of the left and right optical fibers 5a.

The optical connector 7 connects the optical cable 5 in the space B and the optical relay adapter 2, and includes a connection nut 7a, a cable clamp 7b, a ferrule 7c, and a spiral spring 7.
d, a holder 7e, etc. The connection nut 7a is a substantially tubular member, and a part of its surface is knurled. The connection nut 7a meshes with the thread portion of the optical relay adapter 2 and is inserted into the opening portion of the optical relay adapter 2 while holding the outer cover portion of the optical cable 5 for tightening.

The cable clamp 7b is a substantially cylindrical member that holds the ferrule 7c coaxially and holds the holder 7
Press e into the inner circumference. Then, the cable clamp 7b is inserted into the outer peripheral portion of the holding portion 4 by the tightening force of the connection nut 7a. The spiral spring 7d presses the ferrule 7c toward the connecting surface when the connecting nut 7a is tightened, and presses the end surface of the optical fiber 5a against the glass 6.

The ferrule 7c is a substantially pipe member,
It is a member that coaxially holds and protects the optical fiber 5a and also constitutes a connection protrusion of the optical connector 7. For example, zirconia ceramic having high mechanical strength is press-fitted into the tip cylindrical portion of the ferrule 7c. The holder 7e holds the outer periphery of the spiral spring 7d, one end of which is press-fitted into the cable clamp 7b and the other end of which is inserted into the outer cover of the optical cable 5.

The optical connector 8 on the side of the space A also has a connection nut 8a and a cable clamp 8 like the optical connector 7 described above.
b, ferrule 8c, spiral spring 8d, holder 7e and the like. The connection nut 8a is shorter than the connection nut 7a, engages with a stopper provided along the outer peripheral portion of the cable clamp 8b, and meshes with the optical relay adapter 2 via the screw portion 2c.

[0010]

In the structure of the coupling portion including the conventional optical relay adapter 2 and the optical connectors 7 and 8 configured as described above, the glass of the optical relay adapter 2 is vibrated immediately after the rocket is launched by violent vibration and pressure. 6 was damaged, and the zirconia forming the ferrules 7c and 8c was damaged. In addition, the optical signal from the inside of the camera to the outside,
When transmitting through the optical cable 5, there is a problem that light is reflected by the glass 6 and the transmission loss increases at this portion.

The present invention has been made in view of the above-mentioned problems of the prior art, and has a small optical transmission loss at the coupling portion of an optical cable, can completely shield high temperature and high pressure exhaust gas, and is vibration resistant. The object is to realize a pressure resistant optical connector having excellent properties.

[0012]

SUMMARY OF THE INVENTION According to the present invention, there is provided an optical relay adapter having a jack plate having a central opening and a concave portion inside the housing, and a flange portion attached to the concave portion of the jack plate, and holding an optical fiber. A pressure-resistant optical connector having a first optical connector connected to the optical relay adapter from outside the housing and a second optical connector holding an optical fiber and connected to the optical relay adapter from inside the housing The cylindrical portion and the brim portion are integrally formed, and the cylindrical portion meshes with the concave portion of the jack plate to protect the outer peripheral portion of the second optical connector, and the concave portion of the jack plate and the optical relay adapter. A sheet-like airtight packing that is inserted between the flange portion and airtightly holds the inside of the housing, and is attached behind the second optical connector, and has a hollow portion inside which the optical fiber bends, An optical fiber holder for holding the fiber in an airtight state, and a heat-shrinkable tube which is inserted over the outer peripheral portion of the optical fiber holder and the outer peripheral portion of the airtight spacer and shrinks by heat are provided. .

[0013]

According to the present invention having such features, in assembling the pressure resistant optical connector, the airtight packing is inserted into the concave portion of the jack plate and temporarily fixed. Next, the optical relay adapter with the holding portion inserted is attached to the jack plate. Next, the first optical connector is inserted from the outside of the housing, and the connection nut is used to tighten the optical relay adapter. Next, the second optical connector is attached to the optical relay adapter from inside the housing. Then, the optical fibers of the first and second optical connectors are directly brought into contact with each other. Further, the optical fiber located in the hollow portion of the optical fiber holder is free to bend. In this case, the optical fiber itself is not subjected to excessive stress, and the airtight state of the internal space of the optical connector is ensured. The optical transmission loss is also significantly reduced as compared with the case of using glass.

[0014]

1 is a sectional view showing the structure of a pressure resistant optical connector according to an embodiment of the present invention, and FIGS. 2 and 3 are exploded sectional views. When viewed from the jack plate 1 in FIG.
The optical connector 7 is attached, and the second optical connector 10 is attached to the space A in the housing.

A cylindrical recess 1a is provided in a specific portion of the jack plate 1 on the space A side, and a screw portion 1b is formed along the inner peripheral side surface thereof. An airtight packing 11 is attached to the bottom surface of the recess 1a. The airtight packing 11 is a disk-shaped packing having an opening in the center thereof, and secures the airtightness of the internal space when the airtight spacer 12 is attached.

The airtight spacer 12 is formed by integrally forming a cylindrical portion 12a and a flange portion 12b, and a screw is formed on the outer peripheral side surface of the cylindrical portion 12a so as to mesh with the concave portion 1a of the jack plate 1. The flange portion 12b protects the outer peripheral portion of the optical connector 10 and contacts the jack plate 1 to contact the optical connector 10.
The optical relay adapter 13, which will be described later, serves to shield the air from the outside air.

At the tip of the optical cable 5 in the space B,
The same optical connector 7 as the conventional example is provided. The optical connector 7 is composed of a connection nut 7a, a cable clamp 7b, a ferrule 7c, a spiral spring 7d, a holder 7e, etc., as in the conventional example.

The optical relay adapter 13 is formed by integrally forming an annular flange portion and a cylindrical portion, and has a structure in which the optical relay adapter 13 is divided symmetrically when viewed from the cross section along the central axis.
That is, the optical relay adapter 13 includes the integrally formed member of the left flange portion 13a and the screw portion 13b, and the right flange portion 13
It is constituted by an integrally formed member of c and the screw portion 13d. The optical relay adapter 13 connects the optical connectors 7 and 10, and is attached to the jack plate 1 by screwing through the airtight packing 11. Further, the same holding portion 4 as the conventional example is inserted into the cylindrical opening of the optical relay adapter 13.

On the other hand, as shown in FIG.
Is composed of parts having the same structure as the optical connector 8 of the conventional example except for the holder. That is, the connection nut 10a, the ferrule 10c, and the spiral spring 10d are the same as the parts of the optical connector 8. The shape of the cable clamp 10b near the joint is the same as that of the cable clamp 8b, but the other end is shorter than the conventional example.

The holder 14 is a stepped cylindrical member, the right end of which holds the outer peripheral portion of the spiral spring 10d, and
It is press-fitted into the cable clamp 10b. Holder 14
An outer peripheral portion 14a having a large diameter is formed at the left end portion of and the hollow portion 14b is provided therein. Outer peripheral portion 14a
Is a portion where the tube 15 is mounted, and the hollow portion 14b is a space for ensuring a bending space of the optical fiber 5a.

The bushing 16 has a through hole in a part thereof and is press-fitted into the outer peripheral portion 14a of the holder 14. If the adhesive 17 is filled after the optical fiber 5a is inserted into the through hole of the bushing 16, the optical fiber 5a is fixed and the hollow portion 14b is sealed. The tube 15 is a heat-shrinkable tube that is inserted into the outer circumference 14a of the holder 14 and the outer circumference of the flange 12b of the airtight spacer 12 and shrinks when heated.

On the other hand, the ferrule 10c of the optical connector 10
And the ferrule 7c of the optical connector 7 are respectively the optical fiber 5
A is held coaxially and directly abuts in the optical relay adapter 13 without glass. Here, the optical fiber holder of the second optical connector is constituted by the holder 14 and the bushing 16.

To assemble the pressure resistant optical connector according to this embodiment, the airtight packing 11 is inserted into the recess 1a of the jack plate 1 and temporarily fixed. Next, the optical relay adapter 13 in which the holding portion 4 is inserted is fixed to the jack plate 1 by screwing. Then, as shown in FIG. 2, from the space B to the optical connector 7
Is inserted, and the connection nut 7a is fastened to the optical relay adapter 13. The cable clamp 7b is fitted to the outer peripheral portion of the holding portion 4, and the optical fiber 5a is coaxially positioned with the ferrule 7c.

Next, the optical connector 10 is attached to the optical relay adapter 13 from the space A. In this case, similar to the optical connector 7, the cable clamp 10b is fitted to the outer peripheral portion of the holding portion 4 and the connection nut 10a is tightened. At this time, as shown in FIG. 1, the ferrule 10c moves to a position where the ferrule 7c contacts the optical fiber 5a while holding the optical fiber 5a. When the tips of the ferrules 7c and 10c come into contact with each other, a good pressure contact state can be obtained via the spiral springs 7d and 10d. And the ferrule 1 of the optical connector 10
When 0c is retracted by the pressing force of the spiral springs 7d and 10d, the optical fiber 5a in the hollow portion 14a is freely bent as shown by the broken line in FIG.

Therefore, the optical fiber 5a itself is not unduly stressed, and the adhesive 17 provided on the bushing 16 ensures the hermeticity of the internal space of the holder 14. Further, since the outer peripheral portion of the optical connector 10 in the space A is protected by the tube 15, the airtight state of the internal space including the optical relay adapter 13 is secured even if the optical cable 5 itself bends near the jack plate 1. Further, the pressure contact portions of the left and right optical fibers 5a are less damaged, and the optical transmission loss is significantly reduced as compared with the case where the glass 6 is interposed.

A pressure resistance test of the pressure resistance type optical connector assembled in this way was carried out, and when the space A was filled with nitrogen gas of 2 atm, for example, it was possible to endure an operation for 72 hours or more continuously. .

[0027]

As described in detail above, according to the present invention, a part of a commercially available optical connector is modified so that an airtight spacer,
By adding the airtight packing and the tube to the optical connector inside the housing, an optical connector having excellent airtightness and vibration resistance can be obtained. In addition, this optical connector can be attached to a surveillance camera on a rocket launcher, and it can withstand the application of high temperature and high pressure gas even under the condition of launching, and the effect of improving the reliability of optical transmission can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a pressure resistant optical connector according to an embodiment of the present invention.

FIG. 2 is an exploded cross-sectional view (part 1) showing the structure of a pressure-resistant optical connector according to the present embodiment.

FIG. 3 is an exploded sectional view (No. 2) showing the structure of the pressure-resistant optical connector according to the present embodiment.

FIG. 4 is a cross-sectional view showing a structure of an optical connector used in a conventional surveillance camera.

[Explanation of symbols]

 1 Jack Plate 4 Holding Part 5 Optical Cable 5a Optical Fiber 7,10 Optical Connector 7a, 10a Connection Nut 7b, 10b Cable Clamp 7c, 10c Ferrule 7d, 10d Spiral Spring 7e, 14 Holder 11 Airtight Packing 12 Airtight Spacer 12a Cylindrical 12b Collar part 13 Optical relay adapter 13a, 13c Flange part 13b, 13d Screw part 14a Outer peripheral part 15 Tube 16 Bushing 17 Adhesive

Claims (2)

[Claims] 1. An optical relay adapter having a jack plate having an opening at the center and having a recess inside the housing; a flange part attached to the recess of the jack plate; A pressure-resistant optical connector having a first optical connector connected to an optical relay adapter, and a second optical connector holding an optical fiber and being connected to the optical relay adapter from the inside of a housing, wherein a cylindrical portion An airtight spacer in which a collar portion is integrally formed, the cylindrical portion meshes with a concave portion of the jack plate and protects an outer peripheral portion of the second optical connector, a concave portion of the jack plate and a flange of the optical relay adapter. A sheet-like airtight packing that is inserted between the optical fiber and the housing, and that is attached to the back of the second optical connector, in which the optical fiber bends. An optical fiber holder having a hollow portion for holding the optical fiber in an airtight state, a heat-shrinkable tube that is inserted over the outer peripheral portion of the optical fiber holder and the outer peripheral portion of the airtight spacer, and heat-shrinks. A pressure-resistant optical connector characterized by being provided with. 2. The first optical connector has a cylindrical cable clamp that can be inserted into and removed from an outer peripheral portion of a holding portion of the optical relay adapter, and has a thin opening inside, and a shaft of the cable clamp. A ferrule that is inserted in the center to hold the optical fiber, a cylindrical first holder that has a spring holding portion with an opening diameter increased at the end and is press-fitted into the inner surface of the cable clamp, and the cable clamp. A connecting nut that engages with the outer peripheral part of the first holder in the axial direction to apply a pressing force to the first holder and meshes with the cable clamp; And a helical spring that presses in a fiber contact direction, wherein the second optical connector is a tubular cable clamp that can be inserted into and removed from an outer peripheral portion of a holding portion of the optical relay adapter. A ferrule that has a narrow opening inside and is inserted into the axial center of the cable clamp to hold the optical fiber; and a connection nut that engages with the outer peripheral portion of the cable clamp and meshes with the cable clamp; A helical spring extensibleally held by the end of the holder and pressing the ferrule in the contact direction of the optical fiber, wherein the optical fiber holder is a stepped cylindrical member. And a second holder that is press-fitted into the cable clamp, and a bushing that is attached to the back surface of the second holder and that allows the optical fiber to pass through the through hole to hold the optical fiber in an airtight manner. The pressure resistant optical connector according to claim 1.