JPS6341177B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical fiber photoelectric switch used for detecting minute objects, etc., in which a bendable metal pipe is fitted onto the externally leading end of the optical fiber,
By making the fixed part at one end of this pipe flat and flared, the optical fiber type photoelectric switch can easily and accurately point the leading end of the optical fiber to the object to be detected, and can firmly maintain the attached state of the pipe. is intended to provide.

An embodiment of the present invention will be described below with reference to the drawings.

Figures 1 and 2 show a reflective photoelectric switch. In the figures, numeral 10 is a box-shaped case made of synthetic resin, etc.
0 is a case body 10 that is bonded together with adhesive or the like.
0 and a cover 101. Reference numeral 11 denotes a shield plate bent into a U-shape, 12 and 13 are light emitting and light receiving elements, 14 is an element holder, and 15 is a printed wiring board to which an operation display element 16 and the like are attached.

The element holder 14 is formed of synthetic resin or the like into a box shape with an open front end, and locking protrusions 141 formed on both sides are locked into locking holes 111 formed in the flexible plate 11. By stopping it, it is firmly attached inside the case body 100 via this flexible plate 11. Inside the element holder 14, recesses 142 and 143 for element setting are formed in two stages, upper and lower, in the front-rear direction, and a pair of upper and lower protruding walls 144, 145 formed on the rear end surface are provided with the wiring board. Support groove 146, 1 which also serves as an insertion guide of 15
47 (Fig. 3) is formed. Each of the above recesses 1
42, 143 to hold each element 12, 13 by press fit through elastic cylinders 16, 17 made of rubber, etc., and lead terminals 12a, 13 of each element 12, 13.
By brazing and fixing a to the wiring board 15, the light emitting and light receiving elements 12, 13 are integrally attached to the holder 14 together with the wiring board 15, so that they can be easily incorporated into the case body 101. I can do it. In Figure 3, 14
Reference numerals 8 and 149 are formed on the holder 14 to connect each lead terminal 12 of the light emitting and light receiving elements 12 and 13.
This is a through hole that penetrates through a and 13a.

Reference numeral 18 denotes an external lead-out cord connected to the wiring board 15, and drawn out to the outside through a hole 10a formed in the rear wall of the case 10. The cord 18 and the case 10 are made liquid-tight by a packing 19 made of rubber or the like and having a convex cross section. Annular edge portions 20 and 21 are formed in the case 10 to correspond to the large diameter and small diameter portions 191 and 192 of the rubber packing 19, and the packing 19 of these edge portions 20 and 21
The above-mentioned liquid-tight effect is improved by biting into the hole.

22 and 23 are optical fibers, and the optical fiber 2
Reference numeral 2 constitutes an optical path for transmitting the light from the light emitting element 12 to the object to be detected, and optical fiber 23 constitutes an optical path for transmitting the reflected light from the object to be detected to the light receiving element 13. 24 is a holding base for both the optical fibers 22 and 23, and 25 is a stopper. The element setting recess 14 of the element holder 14 is provided on the rear end surface of the holding base 24 as shown in FIGS. 4 to 6.
A convex portion 240 that fits inside the mouth-shaped wall 146 surrounding the cylindrical portion 2 and 143 is formed, and a protrusion 240 on the front end surface is formed.
41 has a fiber insertion hole 242 formed therein. A recess 243 for resin filling, which communicates with the insertion hole 242, is formed in the convex portion 240 of the holding base 24. 247 is a positioning protrusion formed on the protrusion 240, and 150 is a notch formed on the holder 14 to fit with the protrusion 240.

On the upper and lower surfaces of the plug body 25, there are grooves 244 formed on the upper and lower inner walls of the resin filling recess 243,
Grooves 251 and 252 are formed corresponding to the grooves 245, respectively. One end portion 22a, 2 of each optical fiber 22, 23 is inserted into each of these grooves 251, 252, respectively.
3a, one end surface of each of the optical fibers 22 and 23 is connected to the light emitting and light receiving element 1.
2 and 13 can be easily opposed. One end portion 22a, 23 of each of the optical fibers 22, 23
When the fiber a is inserted into the grooves 251 and 252, for example, if the optical fiber 23 is bent with a large curvature, the corner portion will be removed as shown in FIGS. 1, 2, and 4. By forming a conical tapered portion 253 in a portion of the groove 252 corresponding to the groove 252, damage to the optical fiber 23 due to bending can be prevented. Horizontal grooves 2 are provided on both sides of the plug body 25.
54,255 are formed. One end portion 22a, 23a of each of the optical fibers 22, 23 is connected to the stopper 2.
After this plug body 25 is press-fitted into the resin filling recess 243 while fitting into the upper and lower grooves 251 and 252 of 5, the epoxy resin 26 is injected from either one 254 of the horizontal grooves 254 and 255. When the recess 243 is filled, the resin 26 solidifies and the one ends 22a, 23 of the optical fibers 22, 23 are formed.
a is integrated with the holding base 24 together with the stopper 25 and resin 26. The optical fibers 22, 2 are connected by the holder 24, the stopper 25 and the resin 26.
3 holder 27 is constituted. In this case, the other lateral groove 255 serves as an escape port for air when the resin 26 is injected, so that the flow and solidification of the resin 26 are improved.

The other end 22b of both the optical fibers 22, 23,
23b is led out forward from the hole 104 of the conical cylinder part 103 on the front wall of the case 10, and these lead-out parts 22b and 23b are inserted into a bendable metal pipe 28 made of stainless steel, copper, etc. (See Figures 7 to 9). This metal pipe 28 is connected to the other ends 22b, 23 of the optical fibers 22, 23.
It has an inner diameter such that a gap (play) 29 exists between it and b. In this embodiment, in order to maintain the air gap 29, a small diameter auxiliary pipe 3 is used.
0 is used, but this gap holding means may be a spacer such as resin instead of the auxiliary pipe 30.

One end portion 28a of the metal pipe 28 is formed into a flattened shape that widens at the end as shown in FIGS. is attached to.
Of course, one end 28a of the metal pipe 28 is connected to the case 1.
0 may be directly attached.

Reference numeral 31 denotes a relatively hard frusto-conical rubber packing inserted into the metal pipe 28 and interposed in the conical cylinder part 103 of the case 10, and the rear end face thereof is opposed to the partition wall 105 of the case 10. An O-ring portion 310 having a semicircular cross section is integrally formed. An annular protrusion 10 is provided on the inner wall of the conical cylinder portion 103 corresponding to the conical surface of the rubber packing 31.
6 is formed. When the case body 101 and the cover 102 are connected, the rubber packing 3
The annular protrusion 106 bites into the conical surface of the O-ring part 31 due to the elastic deformation of the rubber packing 31.
comes into pressure contact with the partition wall 105, thereby achieving sealing of this portion.

In the above configuration, prior to the detection operation of the object to be detected, the metal pipe 28 is bent appropriately and set so that the other end surfaces of the optical fibers 22 and 23 are accurately oriented toward the object to be detected. In this state, when the light emitting and light receiving elements 12 and 13 are driven, the light from the light emitting element 12 passes through the optical fiber 22 and is irradiated onto the object to be detected. The reflected light from the object to be detected passes through the optical fiber 23 to the light receiving element 1.
The presence or absence of the object to be detected can be detected depending on whether or not light is received by the object.

Here, even if the optical fibers 22 and 23 are flexible, since the other ends 22b and 23b are covered with the metal pipe 28, the metal pipe 28 can be simply bent without preparing a holding means. Thus, the other end surfaces of the optical fibers 22 and 23 can be accurately directed toward the object to be detected. Although both the optical fibers 22 and 23 may be tightly fitted into the metal pipe 28, as in this embodiment, there is a gap 29 between the metal pipe 28 and the optical fibers 22 and 23.
If the gap 29 is made to exist, even if bending operations are frequently performed when facing the object to be detected, the gap 29
This can effectively prevent the metal pipe 28 from breaking due to play. In particular, since the one end engaging portion 28a of the metal pipe 28 is formed in a flattened shape, the pipe 28 is prevented from rotating not only in the axial direction but also in the circumferential direction. It can be firmly fixed and held on the holder 24 side without wobbling.

FIG. 10 shows a modification of the metal pipe 28, in which a thick reinforcing portion 32 is provided on the one end engaging portion 28a side to strengthen the mechanical strength of this portion. In this embodiment, the thick portion 32 is made of another metal pipe with a large diameter, but it may be formed integrally with the metal pipe 28.

FIG. 11 shows yet another embodiment of the metal pipe 28, approximately in the center (mesh-shaped part in the drawing).
A display section 33 is provided to display the bendable range, which can be used as a guide during bending operations. This display portion 33 can be easily formed by applying paint or taping.

Note that in the above embodiment, the light emitting and light receiving element 1
Although the description has been made using a reflective photoelectric switch using elements 2 and 13 as an example, the present invention can be applied to any photoelectric switch having at least one of the elements.

As described above, in the present invention, the lead-out end of the optical fiber led out to the outside is fitted inside a bendable metal pipe supported by a case or a holder. The end surface of the metal pipe can be accurately and easily directed toward the object to be detected without using a special holding means, and in particular, since the one end of the metal pipe is formed into a flattened end, the mounting state of the pipe can be adjusted easily. can be held firmly.

[Brief explanation of drawings]

1 and 2 are a cross-sectional view and an exploded perspective view showing an example of an optical fiber photoelectric switch according to the present invention, FIG. 3 is a perspective view showing an element holder and a wiring board, and FIG. 4 is an optical fiber holder. Figure 5 is a cross-sectional view of the optical fiber holder holding the optical fiber, Figure 6 is a rear view of the holder, and Figure 7 is a partially broken side view showing an example of a metal pipe. 8 is a rear view of the same metal pipe, FIG. 9 is an enlarged sectional view of a packing portion corresponding to the metal pipe, and FIGS. 10 and 11 are explanatory diagrams of different modifications of the metal pipe. 10... Case, 12... Light emitting element, 13...
Light receiving element, 22, 23... Optical fiber, 22a,
23a...One end of each of the optical fibers 22 and 23, 2
2b, 23b...Each lead-out end of the optical fibers 22, 23, 27...Optical fiber holder, 28...Metal pipe, 28a...One end (flat part) of the metal pipe 28.

Claims (1)

[Scope of Claims] 1. A case containing at least one of a light emitting element and a light receiving element, and a case that holds one end of an optical fiber whose other end is guided outside, and which holds one end of the optical fiber. An optical fiber holder for positioning an end face of the optical fiber at a position facing the element, and a bendable metal pipe fitted over the lead-out end of the optical fiber, one end of which is formed into a flat, flared shape. An optical fiber type photoelectric switch in which the flat end portion is attached to the case or the optical fiber holder. 2. The optical fiber type photoelectric switch according to claim 1, wherein a thick reinforcing portion is present on the engagement end side of the metal pipe. 3. The optical fiber type photoelectric switch according to claim 1 or 2, wherein the external lead-out portion of the metal pipe is provided with a display portion that displays a bendable range of the pipe.