JPH0243068Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention is a proximity switch that detects the approach, presence, passage, etc. of an object to be detected, and more specifically, a proximity switch that is equipped with an operation display function to confirm its operation. This relates to proximity switches.

[Prior art]

A proximity switch usually consists of a detection coil, a detection circuit section consisting of an oscillation circuit, a detection circuit, a switching circuit, an amplifier circuit, etc., and cables forming a power supply line or signal line, and a high-frequency current is supplied from the oscillation circuit. When an object to be detected approaches the detection coil, the oscillation state of the oscillation circuit changes, so the detection circuit detects this change, activates the switching circuit, and outputs the detection signal amplified by the amplifier from the cable. It is configured.

A large number of such proximity switches are installed in the field, and recently proximity switches equipped with an operation display function have been used so that it can be confirmed from the outside that each proximity switch is operating reliably.
Many proximity switches equipped with such an operation display function have been proposed and put into practice up to now, one example of which is shown in FIG.

FIG. 4 is a sectional view of a proximity switch having an operation display function described in Japanese Utility Model Application No. 56-4144. In the figure, 1 is a detection coil housed in a core 2, and 3 is a printed circuit board on which a detection circuit is formed.These are housed in a bottomed cylindrical case 4 made of synthetic resin, and filled with synthetic resin 5. and is fixed in one piece. Reference numeral 6 is a transparent synthetic resin member having an extraction hole 7 in the center and a recess 8 adjacent thereto for accommodating a light emitting diode 10 connected to a detection circuit, and the rear opening of the case 4 is closed and sealed. are doing. A cable 9 is connected to the printed circuit board 3 and led out through the mounting hole 7 of the synthetic resin member 6. Reference numeral 11 denotes a cylindrical body that covers the outer periphery of the case and the synthetic resin member 6 and is integrally attached thereto, and a male screw 12 for attachment is provided on the outer periphery.

The proximity switch configured in this way is installed so that the rear side can be seen near where the object to be detected passes, and when the object to be detected approaches the detection coil 1, it outputs a detection signal from the cable 9 and also outputs a light emitting diode. 10 lights up and its operation can be confirmed from the rear.

By the way, when installing a proximity switch on-site, place it in a place where it is difficult to get close to check its operation.
Alternatively, it is often installed in a location that is difficult to see from the rear and can only be seen from above, left and right, or from below. However, in the proximity switch configured as described above, the synthetic resin member 6 is transparent, so even if the light emitting diode 10 emits light, the synthetic resin member 6 itself does not emit light, and the light emitting diode 10 inside is Since you have to see it directly, it has the disadvantage that the light is weak and it is difficult to check from a distance.Also, since you can only check the operation from the rear, depending on the installation location, you may not be able to check the operation.

[Purpose of invention]

The present invention was developed to solve the above-mentioned drawbacks of the conventional technology, and it has a large display section and an operation display function that allows operation to be confirmed not only from the rear, but also from the top, bottom, left, and right directions. The purpose is to obtain a proximity switch.

[Summary of the idea]

The proximity switch according to the present invention consists of a large diameter part and a small diameter part, and a plurality of translucent display windows made of synthetic resin containing a light diffusing agent and extending from the center of the back cover to the peripheral wall of the large diameter part and the rear surface. , and other parts made of opaque synthetic resin are integrally molded, and the small diameter part is fitted into the opening of the case.

[Example of idea]

Figure 1a is a perspective view of the embodiment of the present invention, b is its rear view, c is a rear view of the camera back, and Figure 2 is A of Figure 1a.
-A sectional view, and FIG. 3 is a BB sectional view. In the figure, 21 is a detection coil, 22 is a core, and these are housed in a cylindrical lid 23 with a bottom. 2
4 is a printed circuit board constituting the detection circuit section.
25 is a case provided with a screw on the outer periphery as necessary, one opening is closed and sealed with a lid body 23;
Further, after a printed circuit board 24 is housed inside, a synthetic resin 26 is filled to fix them together.

27 is a back cover equipped with a display section 30;
It consists of a large diameter part 28 whose outer diameter is approximately equal to the outer diameter of the case 25, and a small diameter part 29 whose outer diameter matches the inner diameter of the case 25, and the small diameter part 29 is fitted into the other opening via an O-ring. , the opening is closed and sealed. This back cover 27 is a light diffusing agent (for example, calcium carbonate powder)
A synthetic resin containing multiple translucent particles (e.g. milky white) that radiate from the center to the outer periphery and back surface.
A display window 30 made of, for example, polycarbonate resin,
The other part 31 made of opaque synthetic resin such as polybutylene terephthalate (PBT) resin is integrally molded in two colors. A recess 32 for accommodating a light source 35 such as a lamp or a light emitting diode is formed in the center of the display window 30, and an outlet hole 33 for a cable 36 and a resin injection hole 34 are provided in the center of the back surface. , the light source 35 accommodated in the recess 32 and the cable 36 inserted into the extraction hole 33 are connected to the printed circuit board 2, respectively.
Connected to 4. In the above embodiment, the light source 35 is housed in the recess 32 provided in the back cover 27, but the light source 35 may be inserted into the center of the display window 30 and integrally molded.
In addition, although the case where four display boards 30 are provided is shown, two display boards 30 are provided.
It suffices if it is more than one.

In the present invention configured as described above, when an object to be detected approaches the detection coil 21, the cable 3
6 outputs a detection signal, and the light source 35 emits light to brighten the display window 30 so that the operation can be confirmed. In this case, when the light source 35 emits light,
Since the display window 30 of the back cover 27 is semitransparent and made of synthetic resin containing a light diffusing agent, the light from the light source 35 is diffusely reflected, making the entire display window 30 bright and easy to see. The large diameter part 28 is the case 25
Because it protrudes to the rear, it can be easily seen not only from the rear, but also from the top, bottom, left, and right directions.

In the above description, the case where the cable 36 is taken out from the take-out hole 33 provided at the center of the back of the back cover 27 has been described.
The cable 36 may be taken out from here. The shapes, dimensions, etc. of other parts are not limited to the above embodiments, and can be changed as appropriate without departing from the gist of the present invention.

[Effect of idea]

According to the present invention, the following remarkable effects can be obtained.

(1) Manufacturing is easy because the back cover including the display window is integrally molded using two-color molding.

(2) The display window is semi-transparent and made of synthetic resin containing a light diffusing agent, so the light emitted from the light source brightens the entire display window, making it extremely easy to see.

(3) Since the large diameter part of the back cover protrudes from the case, the operation can be easily checked not only from the rear, but also from the top, bottom, left, and right, regardless of where it is installed.

[Brief explanation of the drawing]

Fig. 1 a is a perspective view of the embodiment of the present invention, b is a rear view thereof, c is a back view of the back cover, Fig. 2 is a cross-sectional view taken along the line AA in Fig. 1, and Fig. 3 is a cross-sectional view taken along the line B-B. , FIG. 4 is a sectional view of an example of a conventional proximity switch. 21...detection coil, 24...printed circuit board,
25...Case, 27...Back cover, 28...Large diameter section, 29...Small diameter section, 30...Display window, 31...
Other parts, 32... recess, 33... extraction hole,
35...Light source, 36...Cable.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) The detection coil and the detection circuit section are housed and sealed in a cylindrical case, and the case is closed by a back cover equipped with a cable outlet hole and a light source for confirming the operation of the detection circuit section. In the proximity switch, a translucent switch is formed of a large diameter part and a small diameter part, and is made of a synthetic resin containing a light diffusing agent and extends from the center of the back cover to the peripheral wall and rear surface of the large diameter part. A proximity switch characterized in that a back cover is formed by integrally molding a plurality of display windows and other parts made of opaque synthetic resin, and the small diameter part is fitted into the opening of the case. (2) The proximity switch according to claim 1 of the utility model registration claim, wherein a male thread is provided on the outer periphery of the case. (3) The proximity switch according to claim 1, wherein the display window is provided with a recess for accommodating a light source in the center thereof. (4) Utility model registration claim 1 in which a light source is inserted into the center of the display window and integrally molded.
Proximity switch as described in section.