JPH0448510Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an improvement of a holder for a radiation thermometer using an optical fiber.

<Prior Art> As a conventional radiation thermometer holder using an optical fiber, the one shown in FIG. 6 is known. In FIG. 6, 1 is an alumina protection tube. The tip of this protection tube 1 is closed, and cavity radiation can be obtained. The radiant heat generated in this cavity is focused by a lens 2 and a first diaphragm 3 placed at the end of the protection tube, reflected through a mirror 4, focused by a second diaphragm 5, and then focused into a first diaphragm. The light is made to enter the optical connector 6. The light incident on the first optical connector 6 is transmitted through the optical fiber 7 and the second optical connector 8 to the conversion section 9, and the temperature of the atmosphere in which the protection tube 1 is placed is measured.

FIG. 7 shows another conventional example, in which a cylindrical gradient index lens (hereinafter simply referred to as a lens) 10
One side of the optical fiber 11 is made to face the object to be measured 12, and the end of the optical fiber 11 is fixed to the condensing section on the other side to transmit light from the object to be measured 12. In this case, the lens 10 and the optical fiber 11 are bonded together using a resin adhesive and housed in the holder 13. This type of device has a simpler structure and can be made smaller than the conventional example shown in FIG.

Radiation thermometers that transmit optical signals using optical fibers are not affected by electromagnetic fields or chemical atmospheres, and there is no risk of ignition or explosion, so they are suitable for signal transmission using electric wires. It has many advantages in comparison.

<Problems to be solved by the invention> However, in the prior art shown in FIG. 6, the radiant heat is focused by a lens, reflected by a mirror, and then incident on the core of the optical fiber. However, there are problems in that alignment is difficult, and there is a risk of misalignment due to changes in ambient temperature, resulting in poor reliability.

In addition, in the conventional example shown in Figure 7, the lens and optical fiber are fixed with a resin adhesive, so if an axial force is applied to the optical fiber exposed outside the holder, the adhesive part will come off. There is a problem with putting it away.

The present invention was developed in view of the above-mentioned problems of the conventional technology, and aims to prevent the fixed part from coming off by providing elasticity against axial force in a radiation thermometer with a structure in which a lens and an optical fiber are connected. An object of the present invention is to provide a holder for a radiation thermometer.

<Means for solving the problems> The configuration of the present invention for solving the above problems is as follows:
In a radiation thermometer in which a lens is housed at the tip of a holder and receives an optical signal via an optical fiber connected to the lens, the holder has a through hole in which the lens and optical fiber are housed, and a flange on the outer periphery. a first metal fitting having first and second small-diameter portions sandwiching the first and second small-diameter portions; a through-hole into which the first small-diameter portion of the first metal fitting is inserted and through which the optical fiber passes; a second metal fitting having a first screw on the outer periphery of the end and a second screw on the inner periphery; a second small diameter portion of the first metal fitting passes through the second metal fitting and the first screw of the second metal fitting; The third part has a screw to which the part is threaded.
a second metal fitting having a flange that is locked to an end of the third metal fitting, a screw that is screwed into the second screw of the second metal fitting, and a through hole through which the optical fiber passes. 4 of the first metal fitting and the second metal fitting of the first metal fitting.
penetrates the small diameter part of the metal fitting and is locked by the flange of the first metal fitting, and when the first to fourth metal fittings are combined,
It is provided with an elastic body that is slightly pressed by the end of the second metal fitting.

<Example> FIG. 1 is a cross-sectional configuration diagram of a holder showing an example of the present invention. In the figure, reference numeral 20 denotes a first metal fitting, which is provided with a through hole in the center of the round bar to accommodate a lens 21 and an optical fiber 22, and has a flange 20a.
The first small diameter part 20b and the second small diameter part 20 are sandwiched between
c is formed. Reference numeral 24 denotes a second metal fitting, which has a hole into which the first small diameter portion 20b of the first metal fitting 20 is inserted and through which the optical fiber 22 passes.
A screw 24a is provided on the outer periphery of one end of the fitting, and a screw 24b is provided on the inner periphery. Reference numeral 25 denotes a third metal fitting, which has a through hole into which the second small diameter portion 20b of the first metal fitting is inserted, and a screw 25a on the inner periphery into which a screw provided on the outer periphery of the second metal fitting is screwed. ing.
26 is a fourth metal fitting having a flange 26a, a through hole is provided in the center, a through screw 26b is provided at one end to be screwed into the screw 24b on the inner circumference of the second metal fitting 24, and a cover is provided at the other end. 28 is fixed by a fixing screw 29. The collar portion 26a is locked to the outer diameter portion of the third metal fitting. Reference numeral 30 denotes an elastic body (in this embodiment, a coil spring) into which the first small diameter portion of the first metal fitting is inserted, and which is arranged at the end of the flange 20a and the second metal fitting 24; When assembled, the ends of the second metal fittings 24 are slightly pressed.

FIG. 2 is an enlarged cross-sectional view of part B of the holder, which is surrounded by a chain line. The same elements as in FIG.
The E part is an adhesive, and the E part connects the lens 21 and the optical fiber 22.

In the above configuration, assume that a force is applied to the part T (see FIG. 1) of the optical fiber 22 exposed to the outside of the holder, and the optical fiber is pulled in the axial direction. As a result, the optical fiber inside the holder is pulled in the direction of the arrow H, and this force is applied to the connection point F of the lens 21 and the optical fiber 22 through the adhesives D and E. In this case, since the adhesive has a certain degree of strength, the force in the direction H is first absorbed by the coil spring 30 moving in the direction of the arrow R. As a result, the force applied to the connection point of the lens 21 and the optical fiber 22 can be alleviated to some extent.

Fig. 3 is a cross-sectional configuration diagram showing another embodiment in which the holder is provided with an air purge mechanism, Fig. 4 is an enlarged sectional view of section B in Fig. 3, and Fig. 5 shows the state in which the metal fittings in Fig. 3 are removed. FIG. In these figures, the first
The same elements as those in FIGS. The sixth metal fitting 32 is divided into two parts: a metal fitting 31 and a sixth metal fitting 32 having a flange at the end.
A part of the flange is cut off, and a stepped portion is provided at the bottom of the third metal fitting 25 to which the flange of the sixth metal fitting 32 is locked, so that air can circulate.

In FIG. 4, reference numeral 31 denotes a fifth metal fitting having a stepped portion having a diameter of large and small, and a through hole for accommodating the lens 21 and the optical fiber 22 is provided in the center of the round bar. Small diameter portion 31a of this fifth metal fitting
protrudes from the through hole of the sixth metal fitting 32, and its large diameter portion is locked at the bottom of the sixth metal fitting 32, and the fifth metal fitting and the sixth metal fitting 32 are shown in a combined state in FIG. It has the same shape as the first metal fitting 20. The first metal fitting 20 also includes such a divided shape.
Note that the end of the third metal fitting 25 is extended along the small diameter portion of the fifth metal fitting 31 to allow air to circulate. 32 (see FIG. 3) is a through hole formed from the outer periphery of the third metal fitting 25 toward the inside, and an air tube 33 is fixed to this through hole 32.

In the above structure, the lens 21 and the optical fiber 22 are arranged through the through holes of each member, and when air is introduced from the air tube 33, the air flows out from the tip of the third metal fitting 25, forming a holder with an air purge. In addition, 34 is an O-ring provided near the tip of the second metal fitting, and is used to prevent air from flowing out from the gap between the small diameter part of the sixth metal fitting 32 and the inner circumference of the second metal fitting 24. It is something.

In the above configuration, the basic configuration is the same as that of the holder shown in Fig. 1, so as explained earlier,
The force applied to the connection point between the lens 21 and the optical fiber 22 can be alleviated to some extent.

Note that stainless steel, aluminum, copper, etc. can be used as the material of the holder, and the shape is not limited to this embodiment.

<Effects of the invention> As specifically explained above with the embodiments, according to the invention, since the structure is elastic against axial force, the connection between the lens and the optical fiber does not easily come off. It is possible to realize a holder for a radiation thermometer that does not require a holder.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional configuration diagram showing one embodiment of the radiation thermometer holder according to the present invention, Fig. 2 is an enlarged sectional view of part B in Fig. 1, and Fig. 3 is another embodiment in which the holder is equipped with an air purge mechanism. FIG. 4 is an enlarged sectional view of part B in FIG. 3, FIG. 5 is a perspective view with the third metal fitting removed, and FIGS. 6 and 7 show conventional examples. It is a configuration explanatory diagram. 20...First metal fitting, 21...Gradient index lens, 22...Optical fiber, 24...Second metal fitting, 25...Third metal fitting, 26...Fourth metal fitting,
30...Elastic body.

Claims (1)

[Scope of utility model registration request] In a radiation thermometer in which a gradient index lens is housed at the tip of a holder and receives an optical signal via an optical fiber connected to the gradient index lens, the holder is connected to the gradient index lens and the optical fiber. a first metal fitting having a through hole in which the light is accommodated, and first and second small diameter parts sandwiching a flange on the outer periphery, and the first small diameter part of the first metal fitting is inserted and the light a second metal fitting having a through hole through which the fiber passes and having screws on the outer and inner peripheries of one end;
a third metal fitting having a screw through which a small diameter portion of the metal fitting passes through and into which a threaded portion on the outer periphery of the second metal fitting is screwed;
a fourth metal fitting having a flange that is locked to an end of the second metal fitting, a screw that is screwed into an inner peripheral screw of the second metal fitting, and a hole through which the optical fiber passes; an elastic body that penetrates the second small diameter part of the metal fitting and is locked at the flange thereof, and is slightly pressed by the end of the second metal fitting when the first to fourth metal fittings are combined; A radiation thermometer holder characterized by comprising: