JPH09171128A - Connection structure of optical transmission tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To connect an optical transmission tube to a connected body such as a light source with good waterproofness. SOLUTION: A cylindrical projection part 11 for connection which has a screw part formed on its outer peripheral surface is projected at the connection place of the connected body, and a ring-shaped projection is formed at the outer peripheral part of a ferrule 6; and a screw part 12 which threadably engages the screw part 8 of the projection part is formed on a tip-side inner peripheral surface at one end part of the optical transmission tube 1 and a cap nut 7 is inserted. At the base-end peripheral edge part of the cap nut 7, a ring-shaped engagement part 9 which abuts against the ring-shaped projection when the cap nut 7 moves forward by a specific distance is projected and one lengthwise end part of the optical transmission tube 1 is inserted into the cylindrical projection part 11 while a gasket 13 is interposed between the tip surface of the projection part 11 and the ring-shaped projection. Then while this gasket 13 is depressed through the ring-shaped projection of the ferrule 6 with the ring-shaped engagement part 9 of the cap nut 7, the screw part of the cap nut 7 is engaged threadably with the screw part 12 of the cylindrical projection part 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for connecting an optical transmission tube to a connected body such as a light source with good waterproofness.

[0002]

2. Description of the Related Art Conventionally, an optical transmission tube having a transparent core filled with a transparent core having a higher refractive index than that has been used for various purposes. In such a case, as shown in FIG. 3, the light transmission tube c is provided in the connecting cylindrical protrusion b of the light source a.
It has been practiced to attach a base d to one end of the insert and insert it, and fix and connect it with a screw e.

However, such a connection mode is not sufficiently waterproof when rainwater splashes on this connection portion, and rainwater enters from between the outer peripheral portion of the base d and the inner peripheral portion of the protruding portion b. ,
The light source a and the light transmission tube c may be deteriorated,
Therefore, the use in such an environment is limited. In this case, even if the light source was completely waterproof, the waterproof property at the connection was insufficient as described above.

The present invention has been made in order to improve the above circumstances, and it is possible to connect an optical transmission tube and an object to be connected such as a light source with a good waterproof property, and in addition, inflammability,
An object of the present invention is to provide a connection structure of an optical transmission tube capable of reliably blocking the invasion of corrosive liquid, gas, etc. into a connection part.

[0005]

In order to achieve the above object, the inventors of the present invention fill a transparent clad with a core having a higher refractive index than the transparent clad, and cover one end of the clad in the longitudinal direction. In a structure in which the one end of an optical transmission tube having a base attached thereto is connected to an object to be connected such as a light source, a connecting cylindrical projecting portion having a threaded portion formed on the outer peripheral surface is formed at a connecting portion of the object to be connected. In addition to projecting, a ring-shaped projection is projected on the outer peripheral portion of the base, and a screw portion that is screwed with the screw portion of the projecting portion is formed on the inner peripheral surface on the tip side at one end of the light transmission tube. When a base nut is inserted into the cap nut, the base end extending rearward from the ring-shaped projection protruding position of the base, and the base nut advances forward a predetermined distance to the inner peripheral edge of the base end of the cap nut, A ring-shaped locking part that abuts the ring-shaped protrusion is provided so as to project the optical transmission. Insert one end in the length direction of the tube into the cylindrical protrusion with a packing interposed between the tip surface of the protrusion and the ring-shaped protrusion, and at the ring-shaped locking portion of the cap nut. Provided is a connection structure for an optical transmission tube, characterized in that a screw portion of a cap nut is screwed with a screw portion of a cylindrical protrusion while pressing the packing through a ring-shaped protrusion of a base.

According to the present invention, as described above, the packing is sandwiched between the cylindrical projection for connection and the ring-shaped projection of the base by pressing the ring-shaped locking portion of the cap nut, It is highly waterproof, and it is possible to reliably block not only rainwater, but also combustible and corrosive liquids and gases from entering the connection part, so that it can be used in places exposed to rainwater, dangerous places, and the like.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. FIG. 1 shows a connection structure of an optical transmission tube according to an embodiment of the present invention. In the figure, reference numeral 1 denotes an optical transmission tube. This tube 1 is filled with a transparent cladding 2 and a core 3 having a higher refractive index than the cladding 2 made of a liquid or fluid liquid core material or a single type solid core material. At the same time, sealing plugs (window materials) 4 are fitted into both ends of the cladding 2 in the lengthwise direction. Also, a cap 5 is fixed to the clad 2 by covering one end in the length direction of the clad 2 by caulking it, and a ring-shaped projection 6 is integrally provided on the rear part of the outer peripheral part of the base 5. In addition, a cap nut 7 is disposed so as to cover the base 5 and be movable in the length direction. A threaded portion 8 that is screwed into a threaded portion 11 of a cylindrical protruding portion 10 described later is formed on the inner peripheral surface of the cap nut 7 on the tip side, and the base end portion of the cap nut 7 has the ring-shaped projection 6 described above. A ring-shaped locking portion 9 is integrally projectingly provided on the inner peripheral edge portion of the base end while being located further rearward, and when the cap nut 7 is moved forward by a predetermined distance, the ring-shaped locking portion 9 is ring-shaped. It is adapted to abut the rear wall of the protrusion 6.

In the drawing, reference numeral 10 denotes a connected body such as a light source. A connecting cylindrical projecting portion 11 is projectingly provided at a connection portion of the connected body 10 with the optical transmission tube 1, and an outer peripheral surface thereof. A screw portion 12 that is screwed with the screw portion 8 is formed.

When one end of the light transmission tube 1 is connected to the connected body 10, the one end is connected to the cylindrical projection 1.
A packing 12 is inserted between the tip end surface of the projecting portion 11 and the ring-shaped projection 6 in the apparatus 1. Next, the cap nut 7 is advanced forward so that the threaded portion 8 is screwed into the threaded portion 12 of the protruding portion 11. When the cap nut 7 advances forward by a predetermined distance due to this screwing, the ring-shaped locking portion 9 of the cap nut 7 contacts the ring-shaped projection 6, and the cap nut 7 further moves.
When the screwing is advanced, the ring-shaped locking portion 9 presses the ring-shaped projection 6 to advance the optical transmission tube 1 forward (to the connected body 10 side), whereby the packing 13 and the tip surface of the protruding portion 11 are formed. This packing 1 is pinched between the ring-shaped projection 6 and
With 3, the liquid or gas such as water or the like can be reliably prevented from entering the insertion part of the one end of the light transmission tube 1 into the protrusion 11 from the outside, and the connection part is sealed in a liquid-tight or air-tight state.

Therefore, the waterproofness of this connection portion is excellent, and even if the connection portion is used in a place where it is exposed to rainwater, rainwater can be prevented from entering the connection portion, and protection from the external environment can be made.

The packing 13 may have any of a circular cross section, an elliptical cross section, a rectangular cross section, and the like.
Further, the material is rubber, plastic, metal, etc., and particularly those having excellent heat resistance, cushioning property, creep property, and airtightness are preferable, and for example, acrylic rubber, urethane rubber, silicone rubber, fluororubber, etc. are suitable. Used,
Fluororesin is also used.

Here, in the connection structure shown in FIG. 1, the clad 2 of the optical transmission tube 1 is exposed to the external environment at a portion other than this connection portion. Of course, this exposed clad portion is a protective tube. Can be protected by.

In this case, it is preferable that the protective tube covers the entire length of the clad 2 and is formed integrally with the base 6. FIG. 2 shows this, and 14 in the figure indicates a protective tube. The protection tube 14 is made of metal and covers the entire length of the clad 2, and has both ends in the length direction of the cap 5a.
Then, by caulking the base portion 5a, the cladding 2
It is fixed to. Further, a ring-shaped projection 6a is provided on the base portion 5a so that the connection state of the optical transmission tube 1 using the protection tube 13 is the same as that of FIG. According to this connection structure, the connection portion and the light transmission tube 1 can be protected more reliably from the external environment. That is, when the protective tube is separated from the base, it is necessary to separately bond the protective tube and the base. Adhesive agents, welding, etc. are used for this bonding, but the bonding strength is not always sufficient. However, if this joint is damaged due to impact or the like, rainwater or the like may hit the clad 2 from here, and rainwater may enter the connected body 10 side from between the base 4 and the clad 2. Integrated protection tube 1
In No. 4, such disadvantage does not occur, and reliable protection from the external environment is made.

[Experimental Example] The light transmission tube was connected to the light source in the mode shown in FIGS. 2 and 3 (in the connection mode shown in FIG. 3, the cladding was covered with the protective tube integrated with the base as in FIG. 2). ), This was immersed in water. As a result, in the case of the connection mode of FIG. 2, the light source did not cause any trouble and operated without any problem, but in the case of the connection mode of FIG. 3, water entered the light source and short-circuited.

As a result of leaving in chlorine gas, no problem occurred in the connection mode of FIG. 2, but in the connection state of FIG. 3, chlorine gas entered the light source and the mirror of the lamp was corroded.

[0016]

According to the present invention, the liquid-tightness and air-tightness of the connecting portion between the optical transmission tube and the connected body are excellent, and the connecting portion is reliably protected from the external environment.

[Brief description of the drawings]

FIG. 1 is a partially omitted sectional view showing one embodiment of the present invention.

FIG. 2 is a partially omitted sectional view showing another embodiment of the present invention.

FIG. 3 is a partially omitted cross-sectional view showing a conventional connection structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical transmission tube 2 Clad 3 Core 4 Sealing plug 6 Base 6a Base part 7 Cap nut 8 Screw part 9 Ring-shaped locking part 10 Connected part 11 Cylindrical protrusion part 12 Screw part 13 Packing 14 Protective tube

Claims (1)

[Claims] 1. An optical transmission tube comprising a transparent clad filled with a transparent core having a refractive index higher than that of the clad, and having a cap attached to cover one end of the clad in the lengthwise direction. In the structure for connecting to the connected body, the connecting cylindrical projecting portion having a threaded portion formed on the outer peripheral surface is projected at the connecting portion of the connected body, and the ring-shaped projection is projected on the outer peripheral portion of the base. And a threaded portion that is screwed into the threaded portion of the protrusion is formed on the inner peripheral surface of the distal end side at one end of the light transmission tube, and the base end is rearward from the protruding position of the ring-shaped protrusion of the base. Insert a cap nut extended to, when the cap nut advances forward a predetermined distance to the inner peripheral edge of the proximal end of the cap nut, a ring-shaped locking portion that abuts against the ring-shaped projection is projected. Insert one end of the light transmission tube in the length direction into the cylindrical protrusion. While inserting the packing between the tip surface of the protruding portion and the ring-shaped projection, the bag is pressed while pressing the packing through the ring-shaped projection of the cap with the ring-shaped locking portion of the bag nut. A connection structure for an optical transmission tube, wherein a threaded portion of a nut is screwed with a threaded portion of a cylindrical protrusion.