JPH0999806A - Safing switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure quick opening/closing operation against shock and a sufficiently long opening/closing time by providing a plural of shock sensors connected one another in parallel and different in response time to shock. SOLUTION: A safing switch 13 has two shock sensors 15, 16 connected each other in parallel, which are different in response time to shock. For the shock sensors 15, 16 to be different in response time to shock, the mass of magnets 15b, 16b and the tension of springs 15c, 16c are selected, specially the sensitivity of lead switches 15a, 16a being adjusted. As a result, the lead switch 15a is closed relatively faster after shock and off relatively shorter after closed, while the lead switch 16a is closed relatively slower after shock and off longer after closed. The safing switch 13 has a sufficient long closing time to ensure actuation of an air bag ignitor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact sensor using a safing switch for detecting an impact applied to a vehicle body in the case of an accident such as an automobile and activating an airbag or seat belt system. It is about.

[0002]

2. Description of the Related Art Conventionally, an air bag system has been used to ensure the safety of passengers when a vehicle collision or the like occurs. Such an airbag system is mounted on an automobile and is configured as shown in FIG. 6, for example. In FIG. 6, the airbag system 1 is
The collision detection / determination device 2, the airbag ignition device 3, the safing switch 4, and the power supply 5 are included.

The collision detection / judgment device 2 has a known structure and detects an impact applied to the body of an automobile.
The circuit is closed when it is determined that the collision is based on the direction and magnitude of the impact. The airbag igniter 3 also has a conventionally known configuration, and when a drive current flows, the powder is ignited to open the airbag.

The safing switch 4 is constructed as one impact sensor using a reed switch, as shown in FIG. 7, for example. This impact sensor is composed of a magnet 7 movably supported by an impact or the like with respect to a reed switch 6 fixedly arranged in the horizontal direction, and a spring 8 for urging the magnet 7 to one side. As a result, when an impact is applied in the direction of the arrow in the drawing,
Due to this impact, the magnet 7 moves to the right against the tension of the spring 8, so that the magnetic flux of the magnet 7 passes through the contact portion of the reed switch 6, and the reed switch 6 is closed. It is like this.

According to the airbag system 1 having such a structure, normally, that is, when no impact is applied, the collision detection / determination device 2 is turned off, and the safing switch 4 and the magnet 7 are illustrated. In the rest position, the magnetic flux from the magnet 7 does not pass through the reed switch 6, so the reed switch 6 is opened and the safing switch 4 is turned off. As a result, the voltage from the power source 5 is not applied to the airbag ignition device 3, so that the airbag ignition device 3 does not operate.

Here, when a shock is applied to a vehicle due to a collision or the like, the collision detection / judgment device 2 detects this shock, and when it is judged that the collision is based on the direction and magnitude of the shock, , The circuit will be closed. On the other hand,
When an impact is applied to the safing switch 4 in the direction of the arrow in FIG. 7, the impact causes the magnet 7 to move to the right from the rest position against the tension of the spring 8 to cause the contact point of the reed switch 6 to move. The department will be closed. Thus, due to the impact, the collision detection / judgment device 2 and the safing switch 4 are both closed, so that the voltage from the power supply 5 is applied to the airbag ignition device 3, and the airbag ignition device is thus activated. 3 is activated and the airbag is opened. As a result, the impact caused by the collision of the passengers of the automobile is alleviated.

[0007]

By the way, in the airbag system 1 having such a structure, the safing switch 4 is closed as quickly as possible in the event of a vehicle collision, and the airbag ignition device is also provided. It is desirable to have a sufficiently long closing time to ensure that 4 operates. However, in the safing switch 4 having the above-described configuration, the closing time due to the collision of the safing switch 4 is determined by the mass of the magnet 7 and the elasticity of the spring 8. It is difficult to make both times compatible, and the return of the magnet 7 to the original position (rest position) by the tension of the spring 8 after the collision is relatively short.

On the other hand, an impact sensor having a plurality of reed switches arranged in the moving path of the magnet 7 is known. The impact sensor 4a shown in FIG. 8 is the impact sensor reed switch 6 shown in FIG. Is connected in parallel with another reed switch 6a.

According to the shock sensor 4a having such a structure, the currents flowing through the reed switches 6 and 6a may be relatively large, so that, for example, two airbags provided in the driver's seat and the passenger's seat are ignited by the airbag. It is possible to deal with the case of opening by the device 3.

However, such an impact sensor having the reed switches 6 and 6a connected in parallel cannot solve the problem that the closing time of the safing switch is short due to the collision or the like.

Further, in order to extend the closing time due to a collision or the like as much as possible, the impact sensor 4 having the structure shown in FIG. 9 is used.
b is also known. As shown in FIG. 9, the impact sensors 4b are connected to each other in parallel and the magnet 7
It is provided with three reed switches 6, 6b, 6c which are arranged so as to be slightly displaced from each other with respect to the moving direction.

According to the impact sensor 4b having such a structure, when the magnet 7 moves against the tension of the spring 8 when an impact is applied, the reed switches 6, 6b, 6 are provided.
As c is moved, the magnet c is sequentially turned on. Therefore, the three reed switches 6, 6b, 6c that are turned on in a mutually offset manner provide a closing time that is substantially longer than the closing time of one reed switch 6.

However, in this case, since there is only one magnet 7 for turning on the contact portions of the reed switches 6, 6b, 6c, the movement of the magnet 7 due to the impact causes the spring 8 to return to the rest position after the impact. However, there was a problem that the time could not be made too long, and a fundamental solution was not reached.

In view of the above points, the present invention provides an impact sensor that can be quickly closed or opened when an impact is applied, and has a sufficiently long closing time or opening time. The purpose is to provide the used safing switch.

[0015]

According to the invention described in claim 1, the above object includes a plurality of impact sensors connected in parallel with each other and having different response times to an impact. Achieved by a safing switch.

The safing switch according to the present invention preferably includes each of the impact sensors including a reed switch and a magnet movably supported around the reed switch along the longitudinal direction.

According to the third aspect of the present invention, the safing switch has a plurality of impact sensors connected in parallel with each other and having different impact response times.
At least one impact sensor (first impact sensor) of the impact sensors includes a reed switch and a magnet movably supported around the reed switch along the longitudinal direction. At least one impact sensor (second impact sensor), a first magnet disposed so as to be movable from a stationary position in the center in all circumferential directions in which an impact should be detected, and a stationary state of the first magnet. A reed switch disposed along a direction perpendicular to the moving direction from the position, and movably supported along the longitudinal direction around the reed switch, and when the first magnet is in a stationary position, And a hollow cylindrical second magnet that is attracted by the first magnet.

According to the above structure, when no impact is applied, the plurality of impact sensors forming the safing switch are opened, so that the entire circuit of the safing switch is opened. Here, when an impact is applied, the impact sensor having a short response time to the impact is first closed, and the impact sensors having a longer response time are sequentially closed. Therefore, when the shock sensor having the longest response time is closed, the entire circuit of the safing switch including the shock sensors connected in parallel with each other is closed. After closing by impact, each impact sensor is sequentially opened again from the impact sensor having a short response time based on its own response time, and returns to its original state.

Therefore, the closing time of each impact sensor is
Because they are offset from each other, the safing switch as a whole provides a relatively long closing time. The impact sensor with the shortest response time closes the circuit at the time of collision, and the impact sensor with the longest response time closes the circuit at the time of collision with the impact sensor with the shortest response time. It will be long enough after the circuit is closed. Thus, as a whole safing switch,
The circuit can be closed quickly in the event of a collision and a sufficiently long closing time is obtained.

Each impact sensor has a reed switch,
When the reed switch includes a magnet movably supported along the longitudinal direction, each impact sensor has a simple structure, so that the entire safing switch can be configured at low cost.

At least one first impact sensor of the respective impact sensors includes a reed switch and a magnet movably supported in the longitudinal direction around the reed switch, and at least one of the other. Two second impact sensors, a first magnet disposed so as to be movable in all circumferential directions in which a shock is to be detected from a stationary position in the center, and a vertical direction from the stationary position of the first magnet to the moving direction. And a reed switch disposed along a different direction, and movably supported along the longitudinal direction around the reed switch, and when the first magnet is in a rest position, attracted by the first magnet. And a second magnet having a hollow cylindrical shape, the second impact sensor is configured such that when the impact is not applied, the first magnet is in the rest position and the second magnet is in the rest position. Is the first magnet Because it is sucked Te, the contact portion of the reed switch, the magnetic field of the second magnet or acts without action. Therefore, the contact portion of the reed switch is opened and the reed switch is turned off.

Here, when an impact is applied, in the second impact sensor, the first magnet moves from the rest position due to the impact, so that the second magnet deviates from the magnetic field of the first magnet, for example, By moving in the direction away from the stationary position due to gravity, the magnetic field of the second magnet acts or does not act on the contact portion of the reed switch. Therefore, since the contact portion of the reed switch is closed and the reed switch is turned on (or off), the impact can be detected by turning the reed switch on and off. Therefore, the second impact sensor has a comparatively long time from when the impact is received until the reed switch is turned on, as compared with the first impact sensor, but the reed switch is continuously turned on. Be long enough.

In this way, the first impact sensor is quickly turned on or off by the impact, and the second impact sensor has a sufficiently long closing time. The circuit can be closed quickly in the event of a collision and a sufficiently long closing time is obtained.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below based on the embodiments shown in the drawings. FIG. 1 shows the configuration of an airbag system incorporating a first embodiment of an impact sensor according to the present invention. In FIG. 1, an airbag system 10 includes a collision detection / determination device 11, an airbag ignition device 12, a safing switch 13, and a power source 14 which are sequentially connected in series.

The collision detection / judgment device 11 has a well-known structure and detects an impact applied to the body of an automobile.
The circuit is configured to be closed when it is determined to be a collision based on the direction and magnitude of the shock. The airbag ignition device 12 has a known structure and is configured to ignite the explosive powder and open the airbag when a drive current flows.

As shown in FIG. 2, the safing switch 13 is composed of two impact sensors 15 and 16 which are connected in parallel with each other and have different response times for impact. Here, the impact sensors 15, 16
Is a single reed switch 15a fixed in the horizontal direction, similar to the impact sensor shown in FIG.
16a, magnets 15b and 16b movably supported by impact, and magnets 15b and 16
It is composed of springs 15c and 16c for biasing b to one side.

In this case, the masses of the magnets 15b and 16b and the tensions of the springs 15c and 16c are appropriately selected so that the shock sensors 15 and 16 have corresponding times for different shocks. In particular, it is effective to adjust the sensitivity of the reed switch of each impact sensor. Thereby, for example, the impact sensor 15 has a relatively short response time and the impact sensor 16 has a relatively long response time. Accordingly, when an impact is applied in the direction of the arrow in the drawing, the magnets 15b and 16b of the impact sensors 15 and 16 move rightward against the tension of the springs 15c and 16c due to this impact, The magnetic flux of the magnets 15b and 16b is the reed switch 15
The reed switches 15a and 16a are closed, respectively.

In this case, since the impact sensors 15 and 16 have different response times for the impact, when the impact is applied, for example, as shown in FIG. 3, the reed switch 15a of the impact sensor 15 is compared. Ams quickly
It is closed at, and thereafter it is opened relatively early after Bms. On the other hand, the reed switch 16a of the impact sensor 16 is closed relatively slowly in Ems,
After that, it is slowly opened after a relatively long closing time Fms.

The airbag system 10 according to the embodiment of the present invention is constructed as described above. Normally, that is, when no impact is applied, the collision detection / judgment device 11 is turned off and the safing switch 13 is used. Since the magnets 15b and 16b are in the rest positions shown in the figure, the magnetic flux from the magnets 15b and 16b does not pass through the reed switches 15a and 16a. Therefore, the reed switches 15a and 16a of the impact sensors 15 and 16 are open, and the safing switch 13 is turned off as a whole. As a result, the voltage from the power supply 14 is not applied to the airbag ignition device 12, so the airbag ignition device 12 does not operate.

Here, when a shock is applied to a vehicle due to a collision or the like, the collision detection / judgment device 11 detects this shock, and when it is judged that the collision is based on the direction and magnitude of the shock, The circuit will be closed. On the other hand, when a shock in the direction of the arrow in FIG. 2 is applied to the safing switch 13, this shock causes each shock sensor 1 to move.
The magnets 15b, 16b of 5, 16 move to the right from the rest position against the tension of the springs 15c, 16c. At this time, referring to FIG. 3, the magnetic flux of the magnet 15b first passes through the contact portion of the reed switch 15a, and the contact portion of the reed switch 15a is closed after a relatively quick time Ams from the collision. , Reed switch 15a
Is turned on, and thereafter, after a relatively short closing time of Bms, the reed switch 15a is turned off.

On the other hand, after a relatively slow time Ems after the collision, the magnetic flux of the magnet 16b passes through the contact portion of the reed switch 16a, the contact portion of the reed switch 16a is closed, and the reed switch 16a is closed.
Is turned on, and then the reed switch 16a is turned off after a relatively long closing time of Fms. Therefore, the safing switch 13 is closed by turning on the reed switch 15a of the impact sensor 15, and the impact sensor 1
When the reed switch 16a of No. 6 is opened, the reed switch 16a is opened, so that the reed switch 16a is quickly closed due to a collision, and a sufficiently long closing time for operating the airbag ignition device 12 is obtained.

In this way, the collision detection / judgment device 11 and the safing switch 13 are both closed by the impact, so that the airbag ignition device 12 is supplied with power from the power source 14 for a sufficiently long time to operate. Since the voltage is applied and the airbag ignition device 12 operates reliably to open the airbag, the impact caused by the collision of the passenger of the vehicle is mitigated.

FIG. 4 shows a modified example of the safing switch 13 according to the present invention shown in FIG.
2 shows an impact sensor 20 used instead of the. In FIG. 4, the impact sensor 20 includes a case 21 that can be attached to a vehicle body of an automobile, and a case 21 that extends in a direction perpendicular to a direction in which an impact should be detected (for example, a horizontal direction). The hollow cylindrical switch case 22 arranged as described above, the reed switch 23 inserted in the switch case 22, and the switch case 22.
Above the reed switch 23, an annular drive magnet (second magnet) 24 slidably fitted along the longitudinal direction of the coil 24, a coil spring 25 for urging the magnet 24 downward,
It is composed of a detection magnet (first magnet) 26 arranged so as to be able to move in a horizontal all-circumferential direction from a stationary position (illustrated position) in the center by an impact.

The drive magnet 24 is composed of a ferrite magnet having a relatively weak magnetic force because the magnetic flux density and the weight thereof are less restricted. For example, the upper end is the N pole and the lower end is the S pole.
It is magnetized so as to form a pole, and has a small diameter portion 24a provided on the outer peripheral surface at the upper end thereof.
The coil spring 25 is fitted inside, and one end of the coil spring 25 is in contact with the end surface of the small diameter portion 24a.
As a result, the drive magnet 24 can be biased downward. Further, in the case 21, the drive magnet 2
A stopper 27 that restricts the downward movement of the drive magnet 24 is provided below the switch 4.

The detection magnet 26 is composed of a rare earth magnet such as neodymium having a strong magnetic force, and as shown in FIG. 4, it is magnetized so that the upper end becomes the N pole and the lower end becomes the S pole, and is formed into a cylindrical shape. At the same time, in the cylindrical hollow portion 21a provided at the upper end of the case 21, it is held at the center stationary position when no impact is applied. As a result, the detection magnet 2
In its rest position, 6 is adapted to attract the drive magnet 24 upward against the tension of the coil spring 25.

The shock sensor 20 according to the present invention shown in FIG.
Is configured as described above, and the detection magnet 26 is held at a stationary position at the center of the hollow portion 21a of the case 21 when no impact is applied. Therefore, the drive magnet 2
4 is magnetically attracted by the detection magnet 26 in the stationary position against the tension of the coil spring 25, and is positioned relatively upward in the case 21. At this time, the drive magnet 24 is relatively distant from the contact portion of the reed switch 23 inserted in the switch case 22. For this reason,
Since the magnetic field of the drive magnet 24 does not act on the contact portion of the reed switch 23, the contact portion is open and the reed switch 23 is in the off state.

From this state, for example, while the automobile is running,
When a shock is applied due to a collision or the like, the shock sensor 20 is abruptly stopped from the state of moving to the left as shown by an arrow X in the drawing. It receives a relatively large negative acceleration.
Therefore, the detection magnet 26 receives an inertial force relatively leftward in the hollow portion 21a of the case 21 based on its inertial mass.

Thus, the detection magnet 26 moves to the left from the center rest position. Therefore, the drive magnet 2
Since the magnetic field of the detection magnet 26 does not act on 4, the drive magnet 24 is quickly moved downward based on the tension of the coil spring 25. As a result, when the magnetic force of the drive magnet 24 acting on the contact portion of the reed switch 23 becomes equal to or larger than a predetermined value, the contact portion of the reed switch 23 is closed by the magnetic force of the drive magnet 24, and the reed switch 23 is closed. Is turned on. The coil spring 25 may be omitted, and in that case, the driving magnet 24
Will fall due to gravity, which can reduce component and assembly costs.

Thus, the contact portion of the reed switch 23 has an annular drive magnet 24 surrounding the reed switch 23.
Since it is closed by means of a relatively large magnetic force, it is closed by a sufficient contact force. Therefore, for example, even when a large current is applied to the reed switch 23, the contact portion of the reed switch 23 is
The magnetic field generated by this large current does not cause the magnetic field to open, and the magnetic field can be reliably closed. After that, the detection magnet 26 moved by the impact as described above.
Is itself formed into a cylindrical shape, and the peripheral wall of the hollow portion 21a is formed into a cylindrical shape,
When it hits the peripheral wall of the hollow portion 21a and is bounced back by the reaction force, this reaction force is dispersed in the rotation direction. Therefore, for example, because the detection magnet 26 rotates along the peripheral wall of the hollow portion 21a and the like, it takes a relatively long time for the detection magnet 26 to return to the rest position, so that the on-time of the reed switch 23 can be kept relatively long. It will be.

When the detection magnet 26 returns to the rest position, the detection magnet 26 causes the drive magnet 24 to move to the coil spring 25.
Aspirate against the tension of. As a result, the reed switch 23 returns to the original OFF state again. Therefore, the reed switch 23 continues to be in the ON state only during the above-described on-switching and off-switching,
Impact sensor 20 will close more slowly and will have a longer closure time as compared to conventional impact sensors.

Now, a safing switch constructed by combining the moving direction of the magnet 15b of the shock sensor 15 and the magnet 26 of the shock sensor 20 in FIG. 2 so as to move in the same direction will be described. FIG. 5 is a time chart showing the operating state of the safing switch when the impact sensor 20 is used. When a shock is applied due to a collision of a car, the shock causes the magnet 15b of the shock sensor 15 to move from the rest position to the spring 15c.
The magnet 26 of the impact sensor 20 moves away from the rest position by moving to the right against the tension of. At this time, referring to FIG. 5, first, the magnetic flux of the magnet 15b passes through the contact portion of the reed switch 15a. For example, the contact portion of the reed switch 15a is closed 5 to 12 ms after the collision, and the reed switch 15a is closed. 15a is turned on and the reed switch 15a is turned off after a closing time of, for example, 30 ms.

On the other hand, as shown in FIG. 5, 20 to 30 ms after the collision, the magnetic flux of the magnet 24 passes through the contact portion of the reed switch 23 of the impact sensor 20, and the contact portion of the reed switch 23. Is closed and the reed switch 23 is turned on. After a closing time of 1000 ms, for example, the reed switch 23 is turned off. Therefore, the safing switch in which the conventional impact sensor 15 and the impact sensor 20 are combined is closed by turning on the reed switch 15a of the impact sensor 15, and
When the reed switch 23 of the impact sensor 20 is turned off, the reed switch 23 is opened, so that the impact sensor 20 is quickly closed due to a collision, and a sufficiently long closing time is obtained for operating the airbag ignition device.

Thus, as a safing switch,
When the safing switch is connected in parallel with the impact sensor 15, the impact sensor 15 can quickly close the safing switch, and the subsequent impact sensor 16 uses the conventional impact sensor 16. It will be held even longer than in the case. This allows
Due to the impact, the collision detection / judgment device 11 and the safing switch 13 are both closed, so that the voltage from the power supply 14 is applied to the airbag ignition device 12 for a longer time to operate. As a result, the airbag ignition device 12 operates more reliably and the airbag opens, so that the impact caused by the collision of the passengers of the vehicle is alleviated.

In the above embodiment, the safing switch 13 has the two impact sensors 15, 16 or 15, 20. However, the safing switch 13 is not limited to this, and the safing switch 13 has three or more different collision response times. A plurality of impact sensors may be provided.

[0045]

As described above, according to the present invention,
When no impact is applied, the plurality of impact sensors forming the safing switch are open, so that the entire circuit of the safing switch is open.

When a shock is applied, the shock sensor having a short response time to the shock is first closed, and the shock sensors having a longer response time are sequentially closed. Therefore, when the shock sensor having the longest response time is closed, the entire circuit of the safing switch including the shock sensors connected in parallel with each other is closed. After that, the respective impact sensors are sequentially opened again from the impact sensor having a short response time, and the original state is restored.

Therefore, the closing of the circuit at the time of collision by the impact sensor having the shortest response time is performed quickly, and the closing time of the circuit at the time of collision by the impact sensor having the longest response time is the shortest response time. Since the circuit is closed sufficiently by the shock sensor, the safing switch as a whole can quickly close the circuit at the time of a collision and can obtain a sufficiently long closing time.

Thus, according to the present invention, there is provided a safing switch using an impact sensor that can be quickly closed when an impact is applied and that has a sufficiently long closing time. .

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an airbag system incorporating a first embodiment of a safing switch according to the present invention.

FIG. 2 is a schematic diagram showing a configuration of a safing switch in the airbag system of FIG.

FIG. 3 is a time chart showing an operating state of the safing switch of FIG.

FIG. 4 is a schematic diagram showing a configuration of an example of a shock sensor having a slow response time of the safing switch shown in FIG.

5 is a time chart showing an operating state of the safing switch when the impact sensor of FIG. 4 is used.

FIG. 6 is a block diagram showing a configuration of an airbag system incorporating a conventional safing switch.

7 is a schematic diagram showing a configuration example of an impact sensor used as a safing switch in the airbag system of FIG.

8 is a schematic view showing a modified example of the impact sensor of FIG.

FIG. 9 is a schematic view showing still another modification of the impact sensor of FIG.

[Explanation of symbols]

 10 Airbag System 11 Collision Detection / Determination Device 12 Airbag Ignition Device 13 Safing Switch 14 Power Supply 15 Impact Sensor 16 Impact Sensor 20 Impact Sensor 21 Case 22 Switch Case 23 Reed Switch 24 Drive Magnet (Second Magnet) 25 Coil Spring ( Spring member) 26 Detection magnet (first magnet) 27 Stopper

[Procedure amendment]

[Submission date] October 13, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction contents]

In this case, since the impact sensors 15 and 16 have different response times for the impact, when the impact is applied, for example, as shown in FIG. 3, the reed switch 15a of the impact sensor 15 is compared. Ams quickly
It is closed at, and thereafter it is opened relatively early after Bms. On the other hand, the reed switch 16a of the impact sensor 16 is closed relatively slowly in Ems, but thereafter is opened relatively slowly in Fms.

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

[Figure 3]

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yuji Tsuda 1-25-252 Komaoka, Tsurumi-ku, Yokohama-shi, Kanagawa Japan Aleph Co., Ltd. (72) Inventor Hirohiro Iwaki 1-28, Komaoka, Tsurumi-ku, Yokohama-shi, Kanagawa No. 52 within Nippon Aleph Co., Ltd.

Claims (3)

[Claims] 1. A safing switch comprising a plurality of impact sensors connected in parallel with each other and having different impact response times. 2. The safe according to claim 1, wherein each impact sensor includes a reed switch and a magnet movably supported in the longitudinal direction around the reed switch. Swing switch. 3. A safing switch having a plurality of impact sensors, which are connected in parallel to each other and have different response times to an impact, wherein at least one impact sensor (first impact sensor) among the impact sensors. Includes a reed switch and a magnet movably supported along the longitudinal direction around the reed switch, and at least another impact sensor (second impact sensor).
The first magnet, which is arranged so as to be movable from the stationary position in the center in all circumferential directions in which the impact should be detected, and the first magnet, which is arranged along the direction perpendicular to the moving direction from the stationary position. An installed reed switch and a hollow cylindrical shape that is movably supported around the reed switch in the longitudinal direction and is attracted by the first magnet when the first magnet is in a rest position. The safing switch, which includes a second magnet and a.