JPH0524235Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention relates to a detection end structure in which an optical fiber is extended from the light emitting/receiving part of a photoelectric switch, and a holding sleeve is placed over the detection end of this optical fiber. A window hole is formed in the side wall of the holding sleeve so that light can be emitted or received laterally without bending the end, and the directivity of the light emitted and received from the window hole can be easily adjusted. The purpose is to provide an aperture mechanism.

2. Description of the Related Art A photoelectric switch is a photoelectric switch that detects the presence or absence of an object by utilizing transmission or reflection of light in a detection space and outputs an electrical output. The present applicant had previously proposed a system in which the tip of an optical fiber was enclosed in a flexible metal sleeve (Utility Model Publication No. 63-
No. 38516 [(Jitsugan No. 57-119146]).

In this structure, the protective coating is removed from the tip of the optical fiber that transmits and receives light, and a thin stainless steel pipe with a total length of, for example, about 10 cm is placed over the tip. Then, the stainless steel pipe is attached to a predetermined position with a thread provided on the outer periphery of the proximal end, and the stainless steel pipe is bent so that the tip faces the detection target, thereby emitting and receiving light from the tip of the optical fiber.

According to this structure, it is possible to pass the stainless steel pipe through a narrow place and detect the inside thereof using a spot-shaped light emitting/receiving area.

However, there is a limit to how small the radius of curvature R can be when bending a stainless steel pipe due to its mechanical properties and the need to maintain the total reflection conditions of the optical fiber. Therefore, when detecting the inner side surface of a hole, it cannot be used unless the diameter of the hole is larger than a certain value.

Therefore, the present applicant devised a device that could solve this bending problem and detect the internal side surface of a thin hole, and filed an application several days before filing the present application (Utility Model Application No. 64-
No. 26708 [Jitsugan No. 62-121204]). The present invention is used in addition to the structure of this earlier application as a rotating cap, and is based on the invention of this earlier application.

Therefore, before explaining the present invention, this underlying technology will be explained.

Technology on which the present invention is based FIG. 10 shows the detection end structure of an optical fiber, which is the premise on which the present invention is based. This is done by covering each detection end of optical fibers 3, 3 extending from the light emitting/receiving part 2 of the photoelectric switch 1 with flexible cylindrical holding sleeves 4, 4 made of stainless steel or the like. A window hole 5 is formed in a part of the side wall of the distal end of the lamp, so that light can be emitted or received in the lateral direction. This detection end part is the 11th
When enlarged in the figure, this is the part directly below the window hole 5 inside the holding sleeve 4, as also shown in FIG.
The tip end surface 3a of the optical fiber 3, which is inserted and held after peeling off the protective coating 6 of polyethylene or the like, is opposed to the reflective surface 8 formed on the metal rod 7. This metal rod 7 has one end cut at an angle of 45 degrees in the axial direction, and the cut surface is mirror-finished to form a reflective surface.The metal rod 7 is inserted from the tip side of the holding sleeve 4 and fixed with adhesive. has been done. Note that a transparent resin 9 is filled in the window hole 5 so as to cover the reflective surface 8 and fill the interior to prevent a decrease in detection sensitivity due to adhesion of dust.

With this configuration, the detection end face 3 of the optical fiber 3
The light emitted from a is bent by 90 degrees by the reflective surface 11, passes through the window hole 5, and heads toward the external space, and the light that enters the window hole 5 from the external space is reflected by the reflective surface 8.
becomes incident on the optical fiber.

Such a reflective surface 8 can also be formed directly at the tip of the optical fiber 3, as shown in FIG. In other words, the tip of the optical fiber 3 is axially
It is formed by cutting at a 45° angle, polishing the cut surface, and then applying metal plating.

Further, the window hole 5 can be cut out and formed in the tip end portion 4a of the holding sleeve 4, as shown in FIG. 14, so that the tip end thereof can be later attached and fixed by fitting with the stepped portion 10.

The detection end structure of the optical fiber (Utility Model Application No. 64-26708), which is the premise of the above-mentioned present invention, is such that the part with the window hole is fixed to the stainless steel pipe (holding sleeve).
Since it is integrated, only this window hole portion cannot be rotated after manufacturing.

Problems to be Solved by the Invention In the optical fiber detection structure described above, the directivity of light emission and light reception is determined by the size and shape of the window hole 5. Therefore, it is necessary to manufacture a special product with the size and shape of the window hole 5 corresponding to the detection target. For example, if a small object is to be detected or if it is desired to increase the detection position accuracy, the window hole 5 must be made smaller.

However, if we try to provide various types of optical fiber detection end structures with different apertures to accommodate various detection targets, manufacturing costs and manufacturing/sales management costs will increase, which is inconvenient for users. .

It is also conceivable to adjust the directivity by attaching a sticker or the like having holes of different sizes and shapes to the window hole portion. However, with this method, the seal easily peels off and is unreliable, and the window hole is minute (for example, 1 mm).
The problem is that positioning is difficult and impractical because it is smaller than a corner].

Therefore, the present invention provides a rotary cap that is used in addition to the detection end structure of the optical fiber according to the earlier application, that is, a structure in which a window hole is formed in the side wall of the sleeve and an inclined reflective surface is formed at the tip of the optical fiber. The purpose is to easily adjust the directivity and increase practicality.

Means for Solving the Problems In order to solve the above-mentioned conventional problems, the detection end structure of the optical fiber provided by the present invention is such that the detection end portion of the optical fiber is inserted and held, and the detection end portion of the optical fiber is inserted and held, and a cylindrical holding sleeve with a window hole formed therein; a reflective surface disposed within the holding sleeve at an angle with respect to its axial direction, facing the external space through the window hole and facing the detection end surface of the optical fiber; The present invention is characterized in that it is equipped with a rotating cap rotatably fitted onto the tip of the holding sleeve and having a plurality of apertures of different sizes and shapes cut out in portions corresponding to the window holes.

Function In the above structure, when one of the slit-shaped or hole-shaped diaphragms is aligned over the window hole by rotating the rotary cap fitted on the tip of the holding sleeve, depending on the size and shape of this diaphragm, , the surface area and shape of the window hole exposed to the outside space are determined. Therefore, the directivity can be easily adjusted by matching which aperture to the window hole.

Example The present invention will be described below with reference to examples.

The present invention is constructed by fitting a rotary cap having a diaphragm into the tip of the holding sleeve 4 having a window hole 5, as already explained in FIGS. 10 to 14.

A first embodiment of this rotary cap is shown in FIGS. 1-3 and will now be described.

The rotary cap 11 is formed from a cylinder made of stainless steel or synthetic resin, for example, which is tapered so that its tip has a slightly smaller diameter. In the narrowed portion of the cylinder 12, slit-shaped notches 13, 13, . . . are formed at equal intervals. The width W of these notches 13, 13... is, for example,
They are made different by 0.5mm or 1mm. Further, the opposite end of the cylinder 12 is covered with a lid 14. Note that if a bottomed cylindrical body is used instead of the cylinder 12, this lid 14 is not necessary.

The rotary cap 11 is placed over the tip of the holding sleeve 4 as shown in FIG.
When one of the holes 3, 13, . This provides the desired directivity. Note that this positioning, which is performed by rotating the rotary cap 11, can be performed smoothly by narrowing the notch side of the cylinder 12 and applying an appropriate tightening force due to elasticity. When the detection target changes and it becomes necessary to change the directivity, use rotary cap 1.
It can be easily adjusted by one rotation. In this case, it is also possible to replace the rotary cap with another rotary cap in which the dimensions and shape of the notches 13, 13, . . . are different. This makes it possible to provide an extremely wide variety of directivity to the detection end of the optical fiber.

The rotary cap of the present invention may be of any shape as long as it can be externally fitted onto the distal end of the holding sleeve 4 in a positionable manner, and various other shapes are possible. As an illustration of this, the second example and the third example are
This will be explained next.

In the second embodiment, as shown in FIGS. 5 to 7, a positioning means is provided between the rotary cap 11 and the holding sleeve 4 by means of recesses and recesses in order to ensure the positioning of the rotary cap. be.
In this embodiment, the retaining sleeve 4 has protrusions 15,1.
5, and recesses 16, 16, .

In the third embodiment shown in FIGS. 8 and 9, circular or oval holes 17, 17, . . . are formed as apertures in the rotary cap 11.
In addition, in this embodiment, the protrusion 1 of the holding sleeve 4
5, 15... and recesses 16, 1 of the rotating cap 11
Since the cylinder 1 is sufficiently positioned by 6...
The aperture on the side where the second aperture was formed has been eliminated.

In short, the present invention is not limited to the first to third embodiments, and the positioning means of the rotary cap 11 and the shape of the aperture may be appropriately designed so that the functions of the present invention described above are exhibited. It is something.

Effects of the invention According to the invention, the directivity of the optical fiber can be adjusted by simply fitting a rotary cap with apertures of different shapes into a holding sleeve and rotating it. Therefore, a single side-view type optical fiber covered with a holding sleeve can be adapted to various detection targets. Moreover, since it is possible to provide a product that is extremely easy to use without increasing costs, the fields of application of this type of optical fiber can be expanded.

[Brief explanation of the drawing]

Figures 1 to 4 show a first embodiment of the present invention, with Figure 1 being a perspective view of the retaining sleeve and rotating cap before fitting, Figure 2 being a side view of the rotating cap, and Figure 3 being a side view of the rotating cap. 2 is a cross-sectional view taken along the line A--A in FIG. 2, and FIG. 4 is a plan view of the distal end portion of the holding sleeve into which the rotating cap is fitted. Figures 5 to 7 show a second embodiment of the present invention, with Figure 5 being a perspective view showing the retaining sleeve and rotating cap before fitting, Figure 6 being a side view of the rotating cap, and Figure 7 being a side view of the rotating cap. 6 is a sectional view taken along line B-B in FIG. 6. FIG. 8 and 9 show a third embodiment of the present invention, in which FIG. 8 is a side view of the rotary cap, and FIG. 9 is a developed view of the aperture forming portion of the rotary cap shown in FIG. 8. FIG. 10 is a perspective view showing an example of attaching an optical fiber to a photoelectric switch, FIG. 11 is a side view of the tip of the holding sleeve, and FIG.
FIG. 2 is a perspective view showing the tips and reflective surfaces of the optical fibers facing each other in the holding sleeve shown in FIG. 11;
3 and 14 are side views showing different structural examples of the tip of the holding sleeve. 3...Optical fiber, 4...Retaining sleeve, 5
... window hole, 8 ... reflective surface, 11 ... rotary cap, 13 ... notch (diaphragm), 17 ... hole (diaphragm).

Claims (1)

[Scope of Claim for Utility Model Registration] A cylindrical holding sleeve into which the detection end of an optical fiber is inserted and held and has a window hole formed in the side wall of the tip; a reflective surface facing the outside space through the window hole and facing the detection end surface of the optical fiber; 1. A detection end structure of an optical fiber, comprising a rotary cap in which a plurality of apertures in the shape of a plurality of apertures are cut out.