JPH0567887B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a seismic sensing device in which a sphere rolls due to earthquake motion.

[Prior Art] As shown in FIG. 5, a conventional earthquake sensor using a sphere has a circular hole 2 at the bottom of a hemispherical container 1, and a sphere 3 is placed on the circular hole 2. At the same time, a switch 4 is provided at the bottom of the container 1, and one end of the switch 4 slidably penetrates the circular hole 2,
The switch 4 is opened and closed by changes in the position of the sphere 3 when it is stationary on the circular hole 2 or when it rolls due to vibration (Utility Model Open in Showa 53-
94168).

Further, Japanese Patent Application Laid-Open No. 63-29286 has proposed a vibration sensor equipped with an automatic centering mechanism.

In this invention, as shown in FIG. 6, a hemispherical container 5 has a circular groove 6 at the bottom, and the sphere 3 is accommodated on this circular groove 6, and the sphere 3 is inserted from the upper part of the container 5. A movable electrode 7 extending around the periphery and a fixed electrode 8 are provided on the outside of the movable electrode 7, and the container 5 is configured to float in an outer case 9 with a liquid having a high specific gravity.

[Problems to be Solved by the Invention] The first conventional example described above does not have an automatic centering mechanism, and when it is attached to a device, it must be fixed horizontally, and after it is fixed, There is a problem in that the seismic sensitivity level changes when the level shifts. Furthermore, since the spring force of the switch 4 was acting on the sphere 3, the seismic sensing level determined by the sphere 3 and the circular hole 2 was unstable.

Although the second conventional example has an automatic alignment mechanism, in order to keep the container 5 floating in the outer case 9, the spring force of the lead wires connected to the two electrodes is reduced. The impact may cause the container to tilt. Also, if the whole thing is turned upside down, liquid with a heavy specific gravity will flow out from between the container 5 and the outer case 9, and even if the outer case 9 is returned to its normal state, the liquid will still be between the container 5 and the outer case 9. The liquid may not enter the container and may flow onto the container 5, causing the container 5 to no longer float.

Furthermore, since the upper part of the movable electrode 7 is fixed, the spring force of the movable electrode 7 is strong, and therefore the sphere 3
If the size was made smaller, large vibrations would be required to close the contacts between the electrodes, and there was a limit to miniaturization. Further, the time during which the sphere 3 rolls from the circular groove 6 and the movable electrode 7 and the fixed electrode 8 are in contact is extremely short, and there is a problem in that only an instantaneous pulse-like contact signal can be obtained.

The present invention has been made by focusing on these conventional problems, and has a simple structure that can always detect a constant vibration level, can detect contact signals for a long time, is compact, and is equipped with an automatic alignment mechanism. The purpose is to provide a seismic sensor.

[Means for Solving the Problems] As a means for solving the above problems, the present invention provides a closed container 12 having a recess 13 at the center of the bottom and housing a sphere 20, and an inner upper part of the container 12. A pivot receiver 15 is provided on the pivot receiver 1.
5, a movable ring 18 suspended around the sphere 20 with a gap around the pivot 17;
When the sphere 20 is subjected to vibration, it rolls from the recess 13 at the bottom of the container 12, thereby causing the movable electrode 19 attached to the upper part of the movable ring 18 to open and close the electrical contact, and the movable electrode 19 inside the container 12 to open and close the electrical contact. A fixed contact 21 is provided at a position facing the electrode 19, and the fulcrum position of the pivot 17 is set slightly higher than the center of gravity of the pendulum system consisting of the movable ring 18 suspended from the pivot 17 and the movable electrode 19, In addition, the container 12 is suspended within the outer case 10 that accommodates the container 12, and the liquid 25 is placed between the container 12 and the outer case 10.

[Function] Next, the function of the present invention will be explained. When this seismic sensor is attached to a fixed object, the container containing the sphere will automatically keep itself level due to its self-aligning mechanism.If an earthquake occurs in this state, the vibration will be transmitted from the fixed object to the outer case, and then , transmitted to the container through the suspension and the liquid as a damper. When the sphere rolls due to vibrations above a certain level, the movable ring swings together with the sphere, and the movable electrode attached to the top of the movable ring contacts the fixed electrode attached inside the container, creating an electrical connection. .

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 is a longitudinal sectional view of a first embodiment of the invention. Inside the outer case 10, a container 12 which is sealed from an upper lid 11 that constitutes a part of the outer case is connected to a hanging string 2.
It is suspended at 4. The container 12 is composed of an inner case 14 having a recess 13 at the center of the bottom, a pivot receiver 15, and an inner lid 16. A movable ring 18 is suspended around the sphere 20 from the pivot receiver 15 with the pivot 17 as a fulcrum. A disk-shaped movable electrode 19 is attached to the upper surface of the movable ring 18.
A donut-shaped fixed electrode 21 is attached to the lower surface of the inner lid 16 so as to face it. Further, lead wires 22 are connected to the movable electrode 19 and the fixed electrode 21, respectively, and are connected to an electrode 23 provided on the outer case 10. Further, a liquid 26 as a damper is contained between the outer case 10 and the inner case 14.

In such a configuration, when this device is attached to a fixed object (not shown), the container 12 is automatically suspended vertically and the sphere 20 is seated on the recess 13.
When an earthquake occurs in this state, the vibration is transmitted from the fixed object to the outer case 10 and further transmitted to the container 12 via the hanging string 24 and the liquid 25.
When the vibration exceeds a certain level, the sphere 20 moves into the recess 13
The movable ring 18 is pushed by the sphere 20 and swings about the pivot 17 as a fulcrum. A movable electrode 19 is fixed at its center on the upper surface of the movable ring 18 so that its circumferential end is a free end.
It moves integrally with the swinging of the movable ring 18 and comes into contact with the fixed electrode 21 provided oppositely.

In the above description, the movable ring 18 and the movable contacts 19 integrally fixed thereto are connected to the pivot 1
In order to construct a pendulum system with 7 as the fulcrum,
In order to prevent the seismic sensitivity level of the sphere 20 from being affected by the pendulum action of the pendulum system, the tip of the pivot 17, that is, the fulcrum, was set at a position slightly higher than the center of gravity of the entire pendulum system. As a result, even if the pendulum system is subjected to vibrations, no pendulum action occurs and therefore the rolling of the sphere 20 is not affected. Furthermore, sphere 2
By setting the gap between the ball 20 and the movable ring 18 to about 0.1 mm, the sphere 20 and the movable ring 1 are separated when at rest.
8 does not make contact, and the sphere 20 is moved into the recess 13 by vibration.
When the ball 20 rolls, the movable ring 18 swings as a unit without restraining the sphere 20.

Moreover, the gap between the movable electrode 19 and the fixed electrode 21 is
This is a gap where both electrodes 19 and 21 come into contact when the sphere 20 moves along the radial dimension of the recess 13.

Incidentally, recently there has been a demand for installing a seismic sensor in a household gas meter to prevent disasters caused by earthquakes. In this case, the conditions are that it is small,
There is a need for a malfunction prevention mechanism that has a self-aligning mechanism and is activated by seismic vibrations but not by other vibrations. As a measure to prevent this malfunction, a contact signal from the electrode of the seismic sensor is detected, and this contact signal is turned on for 30 milliseconds and turned on for 40 milliseconds in cycles of 0.3 seconds, 0.5 seconds, and 0.7 seconds during a three-second period. The system uses software that detects an earthquake and activates the alarm if it is turned off five or more times. However, since the contact signal of the conventional electrode is an impactful contact of metal, there is a repulsion and only an instantaneous contact time can be obtained. For this reason, even if there is an earthquake, the above-mentioned software may not judge it as an earthquake.

The present invention is designed so that the movable electrode 19 and the fixed electrode 21 do not repel when they come into contact so that it can be used for such software, and further,
The contact points are rubbed to ensure electrical contact.

The movable electrode 19 of the present invention will be explained in detail below. As shown in FIG. 2, the movable electrode 19 is composed of a central portion 19a that is attached to the movable ring 18, a contact portion 19b that contacts the fixed electrode 21, and a connecting portion 19c that connects the central portion and the contact portion. . The contact portion 19b has a plurality of convex contacts 19.
b′ is provided.

In this embodiment, the connecting portions 19c are radial, but depending on the thickness of the movable electrode 19, it may be used as a flat plate, the width may be changed, or ribs may be provided.

In this way, when the central portion 19a is fixed, the other ends become free and have sufficient spring. Therefore, when the movable ring 18 swings about the pivot 17 as the sphere 20 rolls out of the recess 13, the movable electrode 19 also swings about the tip of the pivot 17.

When the movable electrode 19 swings, it comes into contact with the fixed electrode 21 provided above and opposite to it, but at this time, the contact 19b' of the movable electrode 19 and the fixed electrode 2
Since the contact with the movable electrode 19 is an elastic contact with a spring property, there is no repulsion, and the time from the contact to the time when the sphere 20 moves in the opposite direction and separates is shown in FIG. The ON state can be maintained as shown.

Furthermore, since the contact point 19b' of the movable electrode 19 moves in an arc with the pivot 17 as the fulcrum, the lateral movement moves as if rubbing the contact point, making the electrical contact between the movable electrode 19 and the fixed electrode 21 more reliable. Therefore, even if the sphere is made small, reliable electrical signals can be detected.

In the above explanation, the fixed electrode 21 was explained only above the movable electrode 19, but if the fixed electrode 21 is provided above and below the movable electrode 19 as shown in FIG. 4, the contact signal will be more reliable. In this case, the contact point 19b' of the movable electrode 19 naturally forms a convex shape upward and downward.

The amount and viscosity of the damping liquid 25 to be placed between the inner case 14 and the outer case 10 are adjusted as necessary so that the container 12 can be placed between the outer case 10 and the damping liquid 25 during an earthquake.
Make it physically vibrate.

[Effects of the Invention] As explained above, according to the present invention, there is no need to level the device at the time of installation, and even if it is tilted after installation, it can automatically maintain the level. The level does not change and remains constant. Furthermore, even if the seismic sensor is returned to its normal position after being laid down, it can immediately return to its normal position. Furthermore, since the pendulum system as a movable electrode part is suspended with a fulcrum slightly higher than the center of gravity of the entire pendulum system, and the gap between the movable ring and the sphere is minute, the sphere is free until the moment of rolling. This ensures that an accurate vibration sensing level can be obtained, and after the ball rolls, the arcuate movement of the contact points allows the contacts to maintain the ON state for the time from contact to separation without rebounding. Moreover, since contact can be ensured, a small sphere can be used, and the whole can be made compact.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a vibration sensor according to the present invention, FIG. 2 is a plan view of a movable electrode, FIG. 3 is a schematic diagram showing a contact signal, and FIG. 4 is a cross-sectional view of another embodiment of the present invention. Figures 5 and 5 are longitudinal cross-sectional views of a conventional vibration sensor, and Figure 6 is a vertical cross-sectional view of a conventional vibration sensor with an automatic centering mechanism. 10...Outer case, 11...Top lid, 12...Container, 13...Recess, 14...Inner case, 15...
Pivot receiver, 16... Inner lid, 17... Pivot, 18... Movable ring, 19... Movable electrode, 2
0... Sphere, 21... Fixed electrode, 22... Lead wire, 23... Electrode, 24... Hanging string, 25... Liquid.

Claims (1)

[Scope of Claims] 1. A closed container 12 having a recess 13 at the center of the bottom and housing a sphere 20, and a pivot receiver 15 provided at the upper inside of the container 12.
When the movable ring 18 is suspended around the sphere 20 with a gap around the pivot 17, and the sphere 20 is subjected to vibration, it rolls from the recess 13 at the bottom of the container 12, thereby forming an electrical contact. A movable electrode 19 is attached to the upper part of the movable ring 18 for opening and closing, and a fixed contact 21 is provided in the container 12 at a position facing the movable electrode 19. The container 12 is placed at a position slightly higher than the center of gravity of the pendulum system consisting of the movable ring 18 and the movable electrode 19, suspended in the outer case 10 that accommodates the container 12, and A seismic sensor characterized in that a liquid 25 is placed between a case 10. 2. The seismic sensor according to claim 1, characterized in that fixed contacts 21 are attached above and below the movable electrode 19. 3. The seismic sensor according to claim 1, wherein the fixed contact 21 is attached to either the upper or lower side of the movable electrode 19.