JPH03194815A - Photoelectric switch - Google Patents

Abstract

PURPOSE:To enable the signal transmission between respective photoelectric switches without special wiring by facing a transmission light projecting element of one photoelectric switch in photoelectric switches adjacent to each other and a transmission light receiving element of the other photoelectric switch. CONSTITUTION:The light emitted from a signal transmission light projecting element 15 of a first photoelectric switch SW1 is transmitted through a second wall part 6 of a case 1 and a third wall part 9 of next photoelectric switch SW3 to reach a signal transmission light receiving element 16 thereof. Consequently, a light projecting element 11 for switching of the next photoelectric switch SW2 emits the light with a modulation as same as a light projecting element 11 of the first photoelectric switch SW1. Similarly in the following, a light projecting element 11 of a next photoelectric switch SW emits the light with a modulation pulse as same as the light projecting element 11 of the photoelectric switch SW2 of the last stage. Action timing of each photoelectric switch at this stage is showed with a figure. Transmission of the emission timing between respective photoelectric switches can be performed without special wiring.

Description

[Detailed Description of the Invention] [Technical Field Subject to the Invention] The present invention relates to a photoelectric switch, and particularly to a device for transmitting the timing of light emission when a plurality of photoelectric switches driven by a modulation method are arranged in parallel. Regarding.

[Prior art]

When a plurality of conventional charging switches that use modulated light are used in series, mutual interference occurs when the projectors emit light at the same time, especially in a transmission type photoelectric switch. In other words, light enters the receiver paired with the projector from another projector, causing the receiver to malfunction.

Conventionally, it was necessary to intentionally shift or match the timing of each floodlight's light emission, and in this case, the light emission timing was adjusted by electrically connecting multiple photoelectric switches to each other using cables, etc. .

This not only increases the number of cables but also complicates the wiring, further making wiring errors more likely.

[Purpose of the invention]

In view of these conventional problems, it is an object of the present invention to transmit light emission timing between charging switches without using electrical wiring.

[Summary of the invention]

In order to achieve the object, this invention provides a light emitting element and a light receiving element for transmission in addition to a light emitting element and a light receiving element for switching in a case of a photoelectric switch, and further includes a light emitting element and a light receiving element for transmission in the case of a photoelectric switch. A transparent portion is provided in the opposing portion. When multiple photoelectric switches are connected in series, the transmitting light emitting element of one charging switch and the transmitting light receiving element of the other photoelectric switch are optically opposed to each other among adjacent charging switches. Among the photoelectric switches adjacent to each other, the light emission timing of one is transmitted to the other photoelectric switch.

〔Example〕

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

That is, in FIG. 1, the housing 2 is molded from a translucent material, and has openings in a first wall 5 and a second wall 6 that intersects with this $1 wall. This opening is covered with a light-transmitting cover 3, and the case 1 is formed by this cover and the housing 2. Further, a lens plate 7 is attached to the opening formed in the wall portion 5 of $1. Further, a holder 8 made of a non-transparent material is housed in the case 1, and is in contact with the lens plate 7 at its inner surface. A light emitting element 11 or a light receiving element 12 for switching is held in this holder. Further, a printed circuit board 13 is housed within the case 1. This board is arranged along the longitudinal direction of the case l and facing the wall part 6 of 911I2 and the wall part 9 of $3 of this case, and is connected to the holder 8 at one end thereof,
Furthermore, it is electrically connected to the light projecting element 11 or the light receiving element 12. Inside the case 1 is a light emitting element 11 for switching.
and a light emitting element 15 for signal transmission in addition to the light receiving element 12
and a light-receiving element 16 are housed therein, among which the light-emitting element 15 is fixed to one surface of the printed circuit board 13 so as to face the third wall 9 of the case l, and the light-receiving element 16 is fixed to one surface of the printed circuit board 13 so as to face the third wall 9 of the case l. It is fixed to the other surface of the substrate 13 so as to face the second wall 6 of the case l.

The switching light emitting element 11 is driven by a modulation method, and therefore emits light with a predetermined modulation pulse. Further, the signal transmission light emitting element 15 is connected to the printed circuit board 1.
3, the light emitting element 11 for switching is linked.

Note that the entire case l does not have to be molded with a transparent material; for example, only the portion facing the light emitting element 15 and light receiving element 16 for signal transmission may be made transparent by two-color molding, or Alternatively, the case 1 may be molded from an opaque material, and a translucent cap or lens may be attached to the portion facing the signal transmission light emitting element 15 and light receiving element 16.

Furthermore, it is desirable that the light emitting element 15 and light receiving element 16 for signal transmission be provided close to both walls s9 and 6, respectively.
This is not the case if the signal level is sufficient.

Further, the cable 17 passes through the other end of the case 1, that is, the fourth wall 10 opposite the first wall 5, is introduced into the case 1, and is connected to the printed circuit board 13.

A plurality of photoelectric switches SW having such a configuration are prepared, and as shown in FIG.
At the same time as overlapping the In2 wall 6 of W2, that is, the cover 3, the second wall 6 of the next photoelectric switch SW3 is further overlaid on the third wall 9 of this photoelectric switch. (not shown) etc. As a result, the light emitting element 15 for signal transmission of the first photoelectric switch SWI and the light receiving element 16 for signal transmission of the next charging switch SW2 are connected to each other. The light receiving elements 16 for signal transmission are aligned with each other in position and are optically opposed to each other.

FIG. 3 is a circuit diagram of the main parts of two adjacent photoelectric switches among the photoelectric switches in the connected state shown in FIG.
and an output transistor 2 at the output end of this oscillation circuit.
A resistor 25 is connected between the emitter of this transistor and the ground terminal 24 of the power supply. Further, between the positive terminal 23 of the power source and the collector of the transistor 22, there is a light receiving element and a corresponding switching light emitting element 11.
and a light projecting element 15 for signal transmission are connected in series.

On the other hand, the second charging switch SW2 has a comparator 26 instead of the oscillation circuit 21 of the first photoelectric switch SWI. A light receiving element 16 for signal transmission, such as a photodiode, and a resistor 27 are connected in series between the positive terminal 23 of the power supply and the ground terminal. The connection point between this resistor and the light receiving element 16 is connected to one input terminal of a comparator 26, and the other terminal of this comparator is connected to a reference voltage source 28 that provides a reference voltage.

Furthermore, a transistor 2 is connected to the output terminal of the comparator 26.
20 base is connected, and the emitter of this transistor is connected via a resistor 25 to the ground terminal 24 of the power supply. Similarly to the first charging switch SWl, a light receiving element 11 for switching and a light emitting element 15 for signal transmission are connected in series between the positive terminal 23 of the power supply and the emitter of the transistor 22. Ru.

Now, if the photoelectric switch shown in Figure 1 is a transmission type, the light emitted from the emitter P will reach the receiver R, which is installed separately from the emitter, as shown in Figure 2, and if If the detected object 30 exists between them, the light will not reach the light receiver R. As a result, the presence or absence of the detected object 30 is detected.

If the photoelectric switch shown in FIG. 1 is of a reflective type, the light emitted from the switching light emitting element hits the object to be detected, is reflected by the object, and reaches the switching light receiving element 12.

If the photoelectric switch shown in FIG. 1 is of a coaxial reflective type, the light emitted from the switching light projecting element 11 is reflected by
(not shown in the figure) and is reflected by this,
The light reaches the light-receiving element 12 for switching, but if there is an object to be detected between them, the light does not reach the light-receiving element 12, so that the presence or absence of the object can be detected.

At this time, since the light projecting element 11 for switching emits light with a predetermined variable pulse, the light projecting element 15 for signal transmission, which is interlocked with this, also emits light with the same modulated pulse.

The operation of the photoelectric switch shown in FIG. 2 will now be explained with reference to FIG. 183 and FIG. 's4.

That is, the light emitted from the signal transmission light emitting element 15 of the first photoelectric switch SWI passes through the second wall part 6 of the case l and the third wall part 9 of the next charging switch SW2 to transmit the signal of this switch. light receiving element 16. As a result, the light emitting element 1 for switching of the next photoelectric switch SW2
1 emits the same modulated light as the light projecting element 11 of the first photoelectric switch SWI. Similarly, the next photoelectric switch S
The light emitting element 11 of W3 emits light with the same modulation pulse as the light emitting element 11 of the preceding photoelectric switch SW2. The operation timing of each photoelectric switch at this time is as shown in FIG.

Further, as shown in FIG. 5, a delay circuit 2 is connected between the comparator 26 and the transistor 22 of the next photoelectric switch SW1.
9, the operation timing of those photoelectric switches is as shown in FIG.

〔Effect of the invention〕

As described above, this invention provides the light emitting element 11 or the light receiving element 12 for switching on the first wall part 5 of the case 1, and intersects with the wall part 5 of tlI4Jl and faces each other in the case 1. Since the light emitting element 15 and the light receiving element 16 for signal transmission are arranged so as to face the wall part 6 of 'iI & 2 and the third wall part 9, respectively, it is possible to use a dedicated This has the effect of allowing signal transmission between each photoelectric switch without the need for additional wiring.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the photoelectric switch of the present invention, FIG. 2 is a longitudinal sectional view of a state in which a plurality of charging switches shown in FIG. 1 are connected in series, and FIG. A main part circuit diagram showing the signal transmission status of two photoelectric switches among the photoelectric switches, Fig. 4 is a timing chart showing the operation timing in the $3 figure, and Fig. 5 is a main part showing a modification of Fig. 3. circuit diagram,! Figure $6 is a timing chart showing the operation timing in Figure 5. DESCRIPTION OF SYMBOLS 1... Case, 2... Housing, 3... Cover 5... First wall part, 6... Second wall part, 7... Lens plate, 8... Holder 9 ...$3 wall, 10
...Fourth wall part % 11... Light projecting element, 12... Light receiving element, 13... Printed circuit board, 15... Light projecting element, 16- Light receiving element, 17... Cable , 21...
・Oscillation circuit, 22...Transistor, 23...Positive terminal, 24...Ground terminal, 25...I resistor, 26
...Comparator 27...Resistor, 28...Reference voltage source, 29...Delay circuit, 30...Detected object. Patent applicant: Yamatake Hanequel Co., Ltd. Figure 3

Claims (1)

[Claims] Switching light emitting element (11) inside the case (1)
It accommodates a light-receiving element (12) for switching, and the element is attached to the first wall (5) of the case (1).
), in case (1) above
Inside is the light emitting element (11) or the light receiving element (12).
) and a light-emitting element (15) for signal transmission and a light-receiving element (16) for signal transmission interlocked with the case (1), which intersect with the first wall (5), respectively. ) are arranged opposite to each other on the second wall (6) and the third wall (9), respectively, and on both walls, at least the light projecting element (1
5) and the light receiving element for signal transmission (
16), a light transmitting part is provided in the part facing the switching light emitting element (11), and the light emitting element (11) for switching is driven by a modulation method. The second wall part (6) and the other third wall part (9) are successively arranged so as to overlap, and the light emitting element (15) for signal transmission in one case and the other case A photoelectric switch characterized in that a light receiving element (16) for signal transmission within the switch is optically connected to each other.