JPS5915903A - Automatic optical switch - Google Patents

Abstract

PURPOSE:To maintain specified operation characteristics even under severe environmental conditions by putting a light shielding body which is automatically displaced according to the input for detection from the outside into and out from a slit formed between the end parts of optical fibers for inputting and outputting. CONSTITUTION:The end faces of an optical fiber 1 for inputting and an optical fiber 2 for outputting are placed oppositely to form a slit 3 in a box 4, and a shielding body 5 is fixed in the top end part of a moving elenent 6 supported by a movable plate 8. The body 5 is held static while the force by a spring 10 and the pressure in a bellows 7 are balanced to each other, then the optical transmission path in the slit 3 between the optical fibers is shielded by said body 5, but when the pressure in the bellows 7 increases according to the input to be detected from the outside, the element 6 moves upward to put the optical transmission path in the state of permitting passage of light. The need for electrical wiring to the switch part is thus eliminated, and the optical switch is usable in a dangerous area where explosive gas is present without receiving any electrical noise. Since no electro-optic transducers are required, always the specified operation is accomplished without change in characteristics even under severe conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an automatic switch used in a control circuit in which a switch section and a main electric circuit section are connected using an optical transmission line.

In an electric circuit, particularly in a control circuit, switching is performed to automatically control electric signals in accordance with human power for detecting external conditions such as pressure or temperature.

For this purpose, a conventional method has been used in which an electric switch is directly connected to a movable element that automatically displaces in response to wave detection input to form an automatic switch and directly close or open an electric circuit. However, circuits using this type of switch have the disadvantage that noise is induced from the outside into the switch circuit's wires, and the switch itself generates sparks and noise when switching, so it is necessary to take measures to prevent this. Further, recently, it has been considered to electrically separate the switch section and the main electric circuit section. That is, the automatic switch section as shown in -F is made independent, and the switch output electric signal is converted into an optical signal by electric to optical conversion, and guided to the main electric circuit section through an optical fiber, where it is converted into an electric signal by optical to electric conversion. After converting it into , it is input into the electric circuit. According to this method, the switch signal is transmitted through an optical fiber, so it is not affected by electrical noise. However, since this switch part consists of an automatic electric switch and an optical transducer, it requires a power source.)
Since the power cord is connected separately from the fiber, wiring becomes complicated and handling is inconvenient. In addition, the characteristics of the growth optical converter used in this switch section change depending on the temperature, and the ambient temperature for use tends to be restricted.

Since drowsiness is transmitted to the switch section, there are disadvantages such as the need for explosion-proof measures or an intrinsically safe structure when the switch is installed in a hazardous area. Additionally, in recent years, switches that use infrared rays have been used to detect moving objects. This switch is an electric to light converter, that is, a light source and a light to
It consists of an electric converter and a part where light is blocked by the moving object, that is, a detection part. The light emitted from the light source is guided directly or by a reflecting mirror or optical fiber to a nearby detection section. This light is blocked when there is a moving object, and when there is no moving object, it enters the nearby light-to-electricity converter section or light receiving section. Here, the light is converted into an electrical signal and transmitted to the outside via a wire. According to this method, the switch does not generate sparks or electrical noise.However, since the output signal from the switch is sent via an electric wire, electrical noise is induced from the outside.

This switch includes an optical converter and an optical-to-electrical converter, so it requires a power source, and the base wire is run separately from the output signal wire, making the wiring complicated and inconvenient to handle.

Furthermore, the characteristics of the bone optical converter and the optical to electrical converter used in this switch change depending on the temperature, and there are restrictions on the ambient temperature at which they can be used. Furthermore, since electricity is sent to the switch,
When the switch is installed in a hazardous area, there are also disadvantages such as the need to provide explosion-proof measures or an intrinsically safe structure.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved automatic switch that does not have the drawbacks of conventional switch sections as described above.

That is, in the present invention, a light input optical fiber and a light output optical fiber are opposed to each other by forming a slit between their ends, and a light shielding body can be inserted into and removed from the slit. , is an automatic light switch characterized in that the light shielding body is fixed to a movable element that is automatically displaced in response to an input to be detected from the outside, thereby achieving the above object.

Hereinafter, specific examples of the automatic optical switch of the present invention will be described with reference to the drawings.

FIG. 1 is a partially cutaway front view of an optical switch according to the present invention in a longitudinal section at the center thereof, and FIG. 2 is a longitudinal sectional view at the center thereof. In the optical switch of the present invention, a light input optical fiber 1 and a light output optical fiber 2 have their ends facing each other and have a slit 3.
are arranged to form a The width of this slit 3 is preferably as narrow as possible. This opposing arrangement is formed within the box 4, and the box 4 is normally shielded from light to prevent noise light from entering the light output optical fiber 2. Note that it is preferable that the optical fiber is protected and shielded from light except for the ends. A light shielding body 5 can be inserted into and taken out of the slit 3. The light blocking body 5 may have a light blocking rate of 100 inches or less than 100 inches. This light shielding body 5 is fixed in the vertical direction near the upper end of a rod 6 which is a movable member. The rod body 6 is supported by a movable plate 8 attached to the upper end of a bellows 7 housed in the lower part of the box 4. A pressure introduction part 9 is attached to the lower part of the box 4, and the inside of the introduction part and the inside of the bellows 7 are communicated with each other. The bellows 7 is pushed downward via a movable plate 8 by a spring 10 located above the bellows 7, and remains stationary under the force of the spring 10 and the pressure introduced from the outside for detection. . In the illustrated balanced state, the light shielding body 5 is located within the slit 3, thereby blocking the optical transmission path between the light input optical fiber 1 and the light output optical fiber 2.

When the test force from the outside is increased, the pressure within the bellows γ increases, and the movable plate 8 rises against the pressing force of the spring 10, pushing the rod 6 upward. As a result, the light shielding body 5 is removed upward from within the slit 3, and the optical transmission path within the slit 3 enters a light transmitting state, which state is maintained until the detected pressure decreases. In repeating the above operation, the light shielding body 5
The relative movement between the box 4 and the rod 6 is restricted so that the box 4 can be completely moved in and out of the slit 3, that is, the rod 6 can only move up and down without rotating.

By adjusting the spring 10 to an appropriate strength using a pressure setting knob, it is possible to appropriately determine a pressure value that serves as a reference for switching between light shielding and light passing. Moreover, contrary to the above, it is also possible to allow light to pass when the pressure is low and to block light when the pressure increases.

FIG. 3 is a side view showing another specific example of the light shielding body of the automatic light switch of the present invention, in which the light shielding portion of the light shielding body 5 has a plurality of portions 5' having different light shielding rates.

By dividing the switch into 5" and 5///, the switch output optical signal can be changed in multiple stages according to the detected introduction pressure. Furthermore, the light blocking rate of the light blocking portion changes continuously. By using the light shield 5, it is possible to continuously change the switch output optical signal according to the introduced pressure to be detected.

Above, we have specifically described the case where the input to be detected is pressure, but if the input is temperature, for example, by using an appropriate means such as the displacement of the moving element by temperature instead of the bellows etc. Automatic optical switches can be constructed in a similar manner. For other inputs to be detected, the automatic optical switch of the present invention is constructed by similarly using appropriate mover displacement means. For example, it can be used as a limit switch by displacing the mover according to the displacement of the relative motion of the mechanical parts.

FIG. 4 is a schematic diagram showing how the automatic optical switch of the present invention is used. The light source for inputting light into the input/output optical fiber of the optical switch is a light-to-light converter attached to the main electric circuit section. The intensity of this light source may be constant or may vary in response to appropriate electrical signals in the electrical circuit. The optical signal from the light source is transmitted through the input optical fiber to the switch section, where it is automatically switched as described above, and the output optical signal is transmitted through the output optical fiber to the optical to electric converter in the main electrical circuit section. Here, the optical signal is converted into an electrical signal and input into the electrical circuit.

According to the automatic optical switch of the present invention as described above, there is no need for electrical wiring to the switch section, it is not subject to ridge noise, the switch section can be made lightweight, and even when flammable and explosive gas is present in the switch section, there is no need for electrical wiring to the switch section. Even if it is necessary to install the switch section in a hazardous area, explosion-proof measures are not required. In addition, since the automatic optical switch of the present invention does not have an electrical to optical converter in the switch section, its characteristics do not change even under severe temperature and other environmental conditions, and it always operates in a constant manner, so it has a wide range of applications. ,.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of an automatic light switch according to the present invention, partially cut away in longitudinal section at the center, and FIG. 2 is a longitudinal sectional view at the center thereof. FIG. 3 is a side view of the light shielding body of the automatic light switch of the present invention. FIG. 4 is a schematic diagram showing how the automatic optical switch of the present invention is used.

Claims (5)

[Claims] (1) The Gwangju optical fiber and the Idemitsu optical fiber are opposed to each other with a slit formed between their ends, and a continuous light body can be put in and taken out of the slit, and the light shielding body is an automatic optical switch that is fixed to a movable element that automatically displaces in response to an external input to be detected. (2) The automatic light switch of paragraph 1, wherein the input to be sensed is pressure or temperature. (3) The automatic light switch according to the first term, wherein the human force to be detected is a displacement of relative movement. (4) The automatic light switch according to item 1, wherein the light shielding body has a plurality of light shielding portions having different light shielding rates. (5) The automatic light switch according to item 1, wherein the light shielding body has a light shielding portion whose light shielding rate changes continuously.