JPH0119730B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of the Invention> The present invention relates to a non-contact switching device used as a limit switch or the like.

<Prior art and its problems> Conventionally, as this type of switching device, by opening and closing the optical path between one end surface of a light-emitting optical fiber and one end surface of a light-receiving optical fiber using a shield light plate,
There are known devices that open and close in a non-contact manner.
(Refer to Japanese Unexamined Patent Application No. 113775/1982, No. 109238/1983, and 76236/1983) Regarding the assembly structure, the case is made into a double structure, and one space has a drive mechanism for the light plate. It is known that the other space houses an optical system that can be opened and closed by a light plate. (Refer to JP-A No. 53-140588.) However, since the optical system is housed in the space where the optical system is housed, the return spring for the light plate and the return spring for the light plate are extremely troublesome to assemble. Dust, oil, etc. generated from the moving surface of
There is a drawback that wear particles enter the optical system and the detection performance deteriorates.

<Objective of the Invention> The present invention has been made in order to improve the above-mentioned drawbacks, and an object thereof is to provide a non-contact switching device with good assembly workability and excellent detection performance.

<Structure and Effects of the Invention> In the present invention, a first inner space is formed by a case of a sensor section in which an actuator is attached and a cylindrical inner case having an inverted U-shaped cross section, and a first inner space is formed in an opening of the inner case. The second part is sealed by tightly fixing the base.
The housing forming the second inner space is removably attached to the case of the sensor section, and the drive mechanism for the light plate is installed in the first inner space, and the housing forming the second inner space is configured to be removably attached to the case of the sensor unit. An optical path converting means in an optical system in which an optical path is opened and closed by a shield light plate and a shield light plate are separately housed in the inner space, and a shaft body is installed astride the first inner space and the second inner space. are closely fitted so as to be movable, and a light plate is fixed to the shaft.

As is clear from the above configuration, the drive mechanism for the light plate and the optical path converting means are housed in separate sealed spaces, forming a double structure in which each space can be separated.

Therefore, dust, oil, and
There is no fear that abrasion powder or the like will enter the optical path converter, and detection performance can be improved.

Furthermore, since the inside of the case of the sensor section is formed in a double structure, the driving section and the optical path converting section can be assembled separately, improving the ease of assembly.

<Description of Embodiment> An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing, as an example, a case where a non-contact switching device according to the present invention is used for a remote operation control system.

In the figure, reference numeral 1 denotes a sensor section having an actuator 2, which is configured as, for example, a limit switch. Reference numeral 3 denotes a signal processing section having a circuit for processing the output signal from the sensor section 1 into a switch signal, etc., and is connected to the sensor section 1 via optical fibers 4 and 5 for light emission and light reception. These constitute switchgear A, A1 to An. Reference numeral 6 denotes a control device, such as a programmable controller, prepared when controlling a plurality of switchgear A1 to An.
It receives the switch signals from A1 to An and performs processing such as calculation and control, and sends command signals based on the processing results to the respective switching devices A1 to An. 7 is a bus for data, etc.

Next, the configuration of the sensor section 1 in the opening/closing device A will be explained with reference to FIGS. 2 to 4.

In the figure, reference numeral 11 denotes a case of the sensor section 1. On the outer surface of the upper wall 12 of this case 11, a shaft 13 at the base end of the actuator 2 is rotatably supported, and a cam mechanism (see FIG. A head portion 14 having a built-in head (not shown) is fixed with a screw body 15. 16 is a groove formed on the outer surface of the upper wall 12 of the case 11 corresponding to the head portion 14;
An O-ring 17 is fitted. 18 is a roller attached to the tip of the actuator 2, and 19 is a mounting hole formed in the case 11.

A through hole 21 communicating with the inner space 20 is formed in the upper wall 12 of the case 11 corresponding to the head portion 14, and a plunger 22 driven by the cam mechanism is installed in this through hole 21 for vertical movement. The plunger 22 can be fitted into the plunger 22, and a spring 23 applies a spring force toward the proximal end of the plunger 22. A holder member 25 holding a shaft body 24 is integrally provided at the tip of the plunger 22, and a holder member 25 is formed of a metal plate or the like and constitutes a part of an optical path converting means to be described later. A light plate 26 is fixed. 27 is a return spring.

The lower wall portion of the case 11 is constructed separately as a base 28, and together with an inner case 29 fitted into the case 11 and having an inverted U-shaped cross section, constitutes a housing 30 for storing an optical path converting means.
The base 28 and inner case 29 have rivets 30
The inner space 32 of the housing 30 is kept liquid-tight by an O-ring 31 interposed between the two 28 and 29. Reference numeral 33 denotes an elastic piece that is fixed to the housing 30 side and stands up along both side surfaces of the case 11, and this elastic piece 33 is removably engaged with an engaging protrusion 34 formed on the side surface of the case 11. A mating engagement hole 35 is formed so that the housing 30 can be attached to and detached from the case 11.

On the lower surface of the base 28, a pair of through holes 36,
37 are formed, and each of these through holes 36, 37
Optical fiber connectors 38 and 3 correspond to
9 is attached with screws 40 or the like. One end portion 4a of each of the light emitting and light receiving optical fibers 4, 5,
5a has the coating layer peeled off, and each one end surface 4b, 5
b is mirror polished. 41 and 42 are respective caps 43 and 4 of the optical fiber connectors 38 and 39;
4, and one end 4a, 5a side of each of the optical fibers 4, 5 is held by the sleeve 4.
1 and 42, and the connector 3 is positioned by tightening the caps 43 and 44.
It is connected and fixed to respective fixing parts 45 and 46 of 8 and 39.

The inner surface of the base 28 has the through holes 36,
A substantially mountain-shaped prism 47 made of a transparent acrylic resin or the like is fixed across the prism 37 . At the top of this prism 47 is the light plate 2.
In addition to the guide and light plate 26, an optical path converting means 49 for converting the light from the light emitting optical fiber 4 to the light receiving optical fiber 5 is formed.
It consists of 50 and 51 are each of the above connectors 3
These are self-occurring lenses provided on the fixed parts 45 and 46 of 8 and 39, respectively, and these lenses are for correcting the light to parallel light, which can greatly contribute to suppressing light loss. Reference numerals 52 and 53 are members for positioning and holding the lenses 50 and 51, respectively.

Next, the specific configuration of the signal processing section 3 will be explained.

In FIG. 5, 54 is a power source, and 55 is a light source consisting of a light emitting diode or the like, which allows light to enter the light projecting optical fiber 4. Reference numeral 56 denotes a light receiving element that receives light from the light receiving optical fiber 4, and is composed of a photodiode or the like. 57 is an amplifier circuit for amplifying the output from the light receiving element 56, and 58 is a waveform shaping circuit for taking out the output from the amplifier circuit 57 as a switching signal.

The light source 55 and the light receiving element 56 are attached to a circuit setting board 60 housed in a controller box 59 shown in FIG. are combined. Reference numerals 63 and 64 denote optical fiber connectors fixed to the box 59 with screw bodies 65 and 65, etc., corresponding to the light source 55 and the light receiving element 56, and the other end 4c of the light emitting optical fiber 4 is connected to one end. The same processing as in the case of the connector 4a is performed, and the connector 63 is connected and fixed to the fixing part 67 by tightening the cap 66. The other end 5c of the light-receiving optical fiber 5 is similarly processed, and is connected and fixed to a fixing portion 69 by tightening the cap 68 of the other connector 64. 70, 71 are sleeves, 72, 7
3 is a self-cleaning lens, and 74 and 75 are holding members for the self-cleaning lenses 72 and 73.

Next, the operation of the above configuration will be explained.

First, the case where the actuator 2 is in the free position will be explained. The light from the light source 55 that has entered the other end of the projection optical fiber 4 is emitted from one end of the optical fiber 4 and enters the prism 47 via the self-occurring lens 50. At the boundary with the self-occurring lens 50, the light spreads at an opening angle corresponding to the unique numerical aperture of the optical fiber 4, but since the self-occurring lens 50 is of λ/4 (λ is the wavelength), At the boundary with the prism 47, the light becomes almost parallel.

The incident light of the prism 47 travels straight as shown in FIG.
The light is reflected at a right angle by the beam b and enters the other end of the light-receiving optical fiber 5. The light guided to the light-receiving optical fiber 5 is received by the light-receiving element 56 with a predetermined efficiency, although the output is slightly attenuated. That is, in this case, the light output level is in the ON state. The output signal from the light receiving element 56 (curve a in FIG. 8) is amplified by an amplifier circuit 57, then shaped by a waveform shaping circuit 58 and processed into a switch signal.

Next, when the actuator 2 receives the operating force and is rotated, the plunger 22 is rotated through the cam mechanism.
is displaced downward, so that the shimmering plate 26 enters the groove 48 of the prism 47 via the shaft body 24. As a result, the optical path between the light-emitting optical fiber 4 and the light-receiving optical fiber 5 is cut off, so that the light output signal level becomes OFF.

As is clear from the above, the prism 47 and the optical plate 26 are housed in the sealed housing 30 consisting of the inner case 29 and the base 28 to form a sealed structure. Inner case 29 with a sealed structure
The inside of the case 11 of the sensor section 1 is formed into a double structure.

Therefore, dust, oil, and
There is no fear that abrasion powder or the like will enter the optical path converting section 11, and detection performance can be improved.

Moreover, since the inside of the case 11 of the sensor section 1 is formed in a double structure, the driving section and the optical path converting section 1
1 and 2 can be assembled separately, improving the ease of assembly.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a state in which a non-contact switching device according to the present invention is incorporated into a remote control system, and FIG. 2 is a perspective view of a sensor section in the device.
3 is a front sectional view of the sensor section, FIG. 4 is a side sectional view of the sensor section, FIG. 5 is a block diagram showing the configuration of the signal processing section of the device, and FIG. 6 is a block diagram of the signal processing section of the device. FIG. 7 is a cross-sectional view of the fiber connection portion of the control box, FIG. 7 is an explanatory diagram of the operation of the optical path converter, and FIG. 8 is a waveform diagram showing the output signal from the light receiving element. DESCRIPTION OF SYMBOLS 1...Sensor part (apparatus main body), 2...Actuator, 3...Signal processing part, 4, 5...Optical fiber, 4
b, 5b...one end surface, 4d, 5d...other end surface, 11...
Case of the sensor section, 20...first inner space, 24...
Shaft body, 27...Returning spring member, 28...Base, 2
9... Inner case, 30... Housing, 32... Second inner space, 36, 37... Through hole, 38, 39... Optical fiber connector, 26... Shiny light plate, 47... Prism, 48... Groove, 49... Optical path conversion means, 50, 51
... self-cleaning lens, 55 ... light source, 56 ... light receiving element, 57 ... amplifier circuit, 58 ... waveform shaping circuit, 5
9...Control box.

Claims (1)

[Claims] 1. A case of a sensor section to which an actuator to be operated is attached, a cylindrical inner case with an inverted U-shaped cross section that is removably attached to this case and forms a first inner space with the case, and this inner case. A housing that tightly fixes a base to the opening of the case to form a sealed second inner space; and a housing that penetrates the top of the inner case and moves axially across the first inner space and the second inner space. a shaft body that is fitted as tightly as possible and driven by the actuator; a spring member that is housed in the first inner space and biases the shaft body with a spring force in a return direction; a light plate fixed to the base and housed in the second inner space; a pair of through holes formed in the base at a predetermined interval; and one end face facing each of the through holes. A light emitting and light receiving optical fiber having one end fixed to the outer surface of the base via an optical fiber connector, and a light emitting light housed in the second inner space and fixed to the inner surface of the base. an optical path converting means that converts the optical path of light emitted from one end surface of the fiber toward one end surface of the light receiving optical fiber, and allows the optical path to be opened and closed by the optical fiber plate; a light projecting element that projects light onto the other end surface of the light projecting optical fiber disposed; a light receiving element that receives light from the other end surface of the light receiving optical fiber disposed outside the case of the sensor section; A non-contact switchgear including a signal processing section consisting of a circuit that extracts a switch signal according to the signal from the light receiving element.