WO2003048785A1

WO2003048785A1 - Falling detection device

Info

Publication number: WO2003048785A1
Application number: PCT/JP2002/012730
Authority: WO
Inventors: Satoshi Teranishi
Original assignee: Ubukata Industries Co.,Ltd.
Priority date: 2001-12-07
Filing date: 2002-12-04
Publication date: 2003-06-12
Also published as: AU2002357585A1; JP4005561B2; JPWO2003048785A1

Abstract

A falling detection device (1), comprising a plurality of falling sensors (3) having movable contacts (35) disposed in metal cylindrical closed containers (101) and having contact parts provided at equal intervals and inertia bodies (36) stored in the closed containers, wherein the inertia bodies (36) press down the movable contacts (35) by their own weights to bring the contacts into contact with fixed contacts (31A) which are the inner peripheral surfaces of the closed containers, whereby the falling sensors can provide the same characteristics in all directions around the center axis of the closed containers.

Description

Description Drop detection device Technical field

The present invention relates to a fall detection device for performing appropriate processing such as detecting a fall of a device to be protected and operating a protection device. Background art

As conventional sensors for drop detection, semiconductor-type three-axis acceleration sensors with high input resolution are often used because the detected acceleration change is as small as 1 G or less. The signal output from the acceleration sensor is amplified by an amplifier circuit, processed by an AZD converter, and determined by a determination circuit. By processing the signal from the semiconductor type 3-axis acceleration sensor in the signal processing circuit 100 in this way, it is possible to determine the position change, movement direction, movement speed, etc. of the device to be protected. it can. Then, when it is determined from the result that the vehicle has fallen by a distance equal to or greater than a predetermined value, the protection device is configured to be activated.

However, the semiconductor type three-axis acceleration sensor has high accuracy and is expensive. In addition, it is necessary to provide an amplifier circuit and an AZD converter for processing the sensor output, one for each of the three axes, which makes the entire signal processing circuit expensive. For this reason, it is inevitable that the entire fall detection device will be expensive. In addition, since the power consumption of the signal processing circuit is large, the usable time is shortened when power cannot be obtained directly from a commercial power supply, for example, when a portable power supply is configured using a battery as a power supply. For this reason, there is a problem that frequent charging and battery replacement are required.

In addition, semiconductor sensors are vulnerable to excessive acceleration due to impact, and are handled with care. Need. For this reason, when used in a portable device, there has been a problem that the sensor output is offset due to, for example, an impact at the time of a fall or the sensor itself is destroyed. Therefore, even if the device to be protected can be protected against falling, the malfunction of the sensor may hinder the use of the device to be protected. There is also a problem with repeated use of the drop detector.

Although it is conceivable to use a mechanical acceleration sensor as a fall sensor instead of the semiconductor sensor, most mechanical acceleration sensors cannot detect a change in gravity with sufficient accuracy. For example, several drop sensors have been proposed in which a plurality of electrodes are provided on the inner surface of a hollow sphere and the electrodes are short-circuited by a conductive sphere or the like disposed inside. However, in practice, the fall sensor having the above configuration is difficult and difficult to manufacture. In addition, unless a biasing force is applied to the conductor or the electrode in a direction of moving away from each other, even if the weight of the conductor is apparently reduced, only the contact pressure is reduced and the contact state between the electrodes is reduced. Will be maintained. Therefore, it does not function as a drop sensor. The above-mentioned problem is not limited to the spherical type, but also occurs in a unidirectional sensor in which a conductor is disposed on an electrode on the bottom of the container.

Therefore, in the drop sensor 1 having the above-described configuration, a configuration that constantly changes the contact state against gravity by an elastic body such as a spring is required. In order to detect a change in gravity, the elastic body is held at a predetermined position by receiving the weight of the inertial body that is hung by 1 G of gravity when stationary, and the apparent weight of the inertial body is determined by dropping or the like. When the value is reduced to a value, it must be configured so that contacts and the like are operated immediately. In particular, as the size of the sensor is reduced, the mass of the inertial body also decreases, so it is necessary to make the elastic body that supports it flexible. Therefore, the smaller the sensor, the more difficult it is to design the sensor. In addition, if the elastic body is made flexible, there is a problem that the elastic body is easily deformed even with an impact acceleration applied to normal handling. For this reason, from the viewpoint of the strength setting and durability of the elastic body, for example, horizontal vibration It is difficult to convert an acceleration sensor that detects such things as a fall sensor that detects acceleration in the direction of gravity by simply arranging it horizontally.

In addition, a unidirectional mechanical accelerometer with a simple structure could be used as the drop sensor. However, in order to detect the fall of the device to which the sensor is attached in any posture, it is necessary to arrange many sensors three-dimensionally with respect to the board to have sensitivity in all directions. This complicates the arrangement of parts and makes manufacturing difficult.

Therefore, an object of the present invention is to provide a fall detecting device which can accurately detect a fall of a target device in any posture, and has a simple configuration and excellent impact resistance. Disclosure of the invention

The fall detection device of the present invention is provided with a metal cylindrical closed container, a movable contact provided in the closed container and having a plurality of contact portions arranged at equal intervals, and provided on an inner peripheral surface of the closed container. A plurality of mechanical drop sensors comprising: a fixed contact that can be separated from and contacted with the movable contact; and a permanent body that is housed in the hermetically sealed container and that pushes down the movable contact by its own weight to contact the fixed contact. I have one. The drop sensor has the same characteristics in all directions around the central axis of the cylindrical closed container, and when in a normal posture in which the central axis of the closed container is a horizontal axis and in a stationary state, When the inertial body deflects the movable contact and comes into contact with the fixed contact, and when the apparent weight of the inertial body is reduced to a predetermined value or less due to dropping or the like, the movable contact is opposed to the weight of the inertial body. Are configured to be separated from the fixed contact. For this reason, the plurality of drop sensors are the same as at least one of the other drop sensors by changing the inclination angle of the central axis of the closed container so that a part of the allowable tilt range for the normal posture overlaps. By arranging on a flat surface, the posture However, a fall can be detected with high accuracy. Moreover, since the drop sensor has the same characteristics in all directions around the central axis of the closed container, the number of drop sensors used is reduced as compared with the case of using a unidirectional drop sensor. Can be. In addition, since a plurality of drop sensors can be arranged on the same plane, the configuration and manufacturing are simplified. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram showing the entire configuration of a fall detection device according to a first embodiment of the present invention, FIG. 2 is a vertical side view of the fall sensor 1,

Fig. 3 is a vertical sectional view of the drop sensor shown in Fig. 2 along the line 3-3.

FIG. 4 is a diagram corresponding to FIG. 1 showing a second embodiment of the present invention, and FIG. 5 is a diagram corresponding to FIG. 1 showing a third embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in more detail with reference to the accompanying drawings. First, FIGS. 1 to 3 show a first embodiment of the present invention. As shown in FIG. 1, a fall detection device 1 according to the present embodiment includes a signal processing circuit 100 including a plurality of components on a substrate 4 housed in a device to be protected 2 and a plurality of fall sensors 3. Etc. are arranged. The drop sensor 3 is a small accelerometer, for example, as disclosed in Japanese Patent Application Laid-open No. 2001-19464 It has substantially the same configuration as the illustrated acceleration sensor.

FIG. 2 is a longitudinal sectional view of the drop sensor 3, and FIG. 3 is a sectional view taken along line 3-3 in FIG. As shown in FIGS. 2 and 3, the drop sensor 3 is provided with a closed container 101 comprising a bottomed cylindrical metal container 31 and a lid plate 32 airtightly fixed to the opening thereof. I have. In this embodiment, the outer diameter of the closed container 101 is 3.3 mm, and the length is The modulus is set to 6.2 mm. The inner peripheral surface 31 A of the metal container 31 is a fixed contact. The cover plate 32 includes a metal plate 32 B having a through hole 32 A, and a rod-shaped conductive terminal 3 air-tightly fixed to the through hole 32 A with an electrically insulating material 34 such as glass. It consists of three.

A metal movable contact 35 having a plurality of movable portions 35 A having a panel property is conductively fixed to a tip inside the container 31 of the conductive terminal 33. In a planar state before assembly, the movable contact 35 is configured such that a movable portion 35A radially extends from the center thereof. The movable contact 35 is welded and fixed to the conductive terminal 33 with its center portion sandwiched between the end surface of the conductive terminal 33 and the metal backing plate 39. It is fixed to the conductive terminal 33. Further, by sandwiching the movable contact point 35 between the backing plate 39 and the resin insulation holder 38, the movable portion 35A is bent at a predetermined angle with respect to the center of the movable contact 35. -Will be kept. In this embodiment, when the movable portion 35A is in a free state without an inertia body 36 described later, the movable portion 35A extends along the longitudinal direction (the left-right direction in FIG. 2) of the inner peripheral surface 31A of the container 31. They are arranged at equal intervals in the circumferential direction. The tip of each movable portion 35A is bent toward the inner peripheral surface 31A of the container 31 to form a contact portion 35B. With the above configuration, the movable portion 35A contacts the inner peripheral surface 31A of the metal container 31 which is a fixed contact at the tip of the contact portion 35B. Therefore, since the contact portion 35B contacts the inner peripheral surface 31A with a small area close to the point contact, the contact pressure is increased, and a contact failure due to contamination of the inner peripheral surface 31A of the container is prevented. I'm sorry.

A metal inertia body 36 is disposed inside the container 31. In the present embodiment, the diameter of the inertial body 36 is set to 2.4 mm. The posture of the drop sensor 3 when the metal container 31 (closed container 101) is arranged so that the central axis thereof is the horizontal axis is the normal posture. When the drop sensor 3 is arranged in a normal posture and is stationary, the inertial body 36 bends the movable portion 35 A by its own weight. While pressing down, the contact portion 35 B contacts the inner peripheral surface 31 A of the metal container 31. Therefore, normally, the metal container 31 and the conductive terminal 33 are electrically connected. An electric insulator 37 such as a resin is disposed on the closed bottom surface of the metal container 31. This prevents conduction between the movable contact 35 and the metal container 31 through the inertial body 36 when the contact portion 35B is separated from the container inner surface 31A. When the surface of the inertial body 37 is covered with an electrical insulator, or when the entire inertial body 37 is made of an electrical insulator, the electrical insulator 37 can be omitted.

The movable contact 35 is made of a very thin metal plate having conductivity, in this embodiment, a phosphor bronze plate having a thickness of 12 Aim. Therefore, if it is repeatedly caught between the inertial body 36 and the inner surface of the container, it may be deformed by extension. In addition, when the drop sensor 3 'receives an impact acceleration and the inertial body 36 hits the movable contact 35 near the holding portion between the insulating holder 38 and the contact plate 39, the movable contact 3'5 is elastically deformed. There is a possibility of plastic deformation beyond the region. Therefore, in the present embodiment, the protrusion 38 A is provided on the insulating holder 38. As a result, even if the inertia body 36 moves to the backing plate 39 side, the inertia body 36 comes into contact with the protruding portion 38A, so that the movable contact 35 by the holding portion 38 and the backing plate 39 is formed. Does not hit near the holding part. Therefore, even when the drop sensor 13 receives an impact acceleration, the inertial body 36 does not apply excessive stress to the movable portion 35 A, and the plastic deformation of the movable contact 35 and the characteristic change accompanying it are prevented. Can be prevented.

Further, a plurality of columnar portions 31B are provided at equal intervals on the inner peripheral surface 31A of the metal container 31. The columnar portion 31B projects in a columnar shape inside the container 31. As shown in FIG. 3, the size and height of the adjacent columnar part 31B are such that when the inertial body 36 and the columnar part 31B come into contact with each other, the inertial body 36 It is set not to reach 1 A. Further, the movable portion 35A of the movable contact 35 is disposed between the adjacent columnar portions 31B. Thereby, even when the movable part 35 A and the inertial body 36 come into contact with each other, a gap always occurs between the inner surface 31 A of the container 31 and the inertial body 36. Because of this, In this case, it is possible to prevent the movable portion 35 A from being extended and from being deformed or changed in characteristics. As described above, the fall sensor 3 according to the present embodiment uses a semiconductor type acceleration sensor because of its structure, it does not change its characteristics even under the impact acceleration given in normal handling or long-term use. No special handling is required.

In the drop sensor 13, since the apparent weight of the inertial body 36 decreases in the fall state, the bent movable portion 35 A pushes the inertial body 36 back to the center of the container 31. At the same time, the contact with the inner peripheral surface 31A of the container 31 is released. Therefore, conduction between the metal container 31 and the conductive terminal 33 is cut off. In this way, the contact state can be reliably switched when the fall sensor 3 is in the fall state.

In order for the drop sensor 3 to be turned on by gravity, the inclination of the central axis of the container 31 is set within a predetermined angle with respect to the horizontal axis, and the movable part 35 A is sufficiently bent by the inertial body 36. Must be brought into contact with the inner peripheral surface 31 A of the metal container 31. For example, if the center axis of the drop sensor 3 is inclined by a predetermined angle or more with respect to the horizontal axis, the inertia body 36 The weight does not work sufficiently in the direction of contacting the bottom surface and bending the movable part 35 A. Therefore, the contact part 35 B is moved from the inner peripheral surface 31 A by a slight change in gravity due to vertical movement. Furthermore, when the inclination of the central axis of the drop sensor 3 increases, the inertia body 36 is moved to the center of the container 31 by the movable portion 35 A, so that the contact portion 3 is provided regardless of the magnitude of gravity. 5 B does not contact the metal container 31. Therefore, only one drop sensor 3 Is no problem if you were inclined about the central axis of the container 3 1, if the central axis is inclined Ru can be permanently malfunction.

In view of this, the drop detecting device 1 is configured such that the plurality of drop sensors 3 are arranged on the substrate 4 and the center axes of the containers 31 of the plurality of drop sensors 3 are located on the same plane. In addition, the upper and lower limits of the permissible range of operation of each Here, the drop sensor 3 is arranged while changing the inclination angle within the allowable inclination angle so that at least one of the other drop sensors 3 overlaps the range where the normal operation is performed.

According to the above configuration, for example, when the drop detection device 1 is disposed on a device to be protected such as a notebook computer so that the substrate 4 is horizontal, the centers rt of all the drop sensors 3 are horizontal. For this reason, all the fall sensors 3 close the contacts when stationary, and all the fall sensors 3 open the contacts when falling. Each drop sensor 3 is cylindrical and has uniform characteristics in all directions with respect to its central axis, so that the substrate 4 can be rotated about any axis parallel to the substrate surface. Even if is changed, the inclination of at least one central axis of the drop sensor 3 with respect to the horizontal axis falls within the allowable error.

Therefore, even when the equipment to be protected is used in an inclined state, or when the board is placed in an inclined state or in a vertical state, at least one drop sensor 13 always contacts the contacts in a stationary state. While keeping the contact state, it can perform normal operation against falling. In addition, since the drop sensor 3 has the same characteristics in all directions with respect to its central axis, the front and back and the lateral inclination of the sensor 3 do not matter when placed on a substrate or the like. Considering only the direction of the shaft makes handling easy. When a unidirectional mechanical acceleration sensor is used, it is necessary to arrange the sensor three-dimensionally in order to have sufficient sensitivity in all directions around the three axes. In the case of the drop sensor 3, the central axes can be aligned on the same plane, which facilitates manufacturing.

The drop sensors 3 are all arranged in parallel on a circuit to form an OR circuit, so that an ON signal can be always input to the signal processing circuit 100 when in a stationary state. Then, as described above, when the fall detection device 1 falls and the apparent weight decreases, the fall sensor 3 in the normal posture moves the movable portion 35 A to the inertial body 36. Since the contact part 35 B is pushed back to the center of the container 31 and the contact part 35 B is separated from the metal container 31, the output is reliably turned off. In addition, the drop sensor 3 tilted beyond the allowable tilt range is distributed faster than the drop sensor 3 in the normal posture because the weight of the inertial body 36 is dispersed from the direction perpendicular to the movable part 35 A. Open contacts or keep contacts open from the beginning. When the signals from all of the fall sensors 3 are turned off in this way, the signal processing circuit 100 determines that the fall detection device 1 has entered the fall state. Here, since the signal from the drop sensor 13 does not need to be particularly amplified or A / D converted, the signal processing circuit 100 is simpler than when a semiconductor sensor is used and also consumes less power. It can be kept low. Therefore, for example, even when the power source is a battery, it can be used for a long time.

By the way, the drop sensor 3 has a switch structure which is very sensitive to a change in gravity but has contacts at the same time. As a result, the inertial body 36 may oscillate and repeat contact opening and closing even with the normal use of the equipment to be protected, and such an OFF signal may cause a false determination of a drop. is there.

Therefore, the signal processing circuit 100 of the drop detecting device 1 does not simply look at the off state of the drop sensor 13, but the state where the signal from the drop sensor 3 is turned off has reached a predetermined time. It is determined whether or not to perform the protection operation based on whether or not. That is, if the signal from the drop sensor 13 is turned off within a predetermined time even if it is once turned off, it is determined that there is no problem due to normal use. On the other hand, if the signal from the drop sensor 13 has been turned off for more than a predetermined time, it is determined that the drop state has continued and the drop has a height that requires protection. Appropriate protection processing is performed on the devices to be protected, for example, by temporarily stopping the recording operation for the device overnight or turning off the power. Furthermore, by filtering the signal from each of the drop sensors 3 individually, noise signals with extremely short intervals at which the contact state of the contact that occurs during the movement of the inertial body 36 is unstable are not detected. In this way, malfunction and non-operation of the protection circuit can be prevented.

FIG. 4 shows a second embodiment of the present invention, and different points from the first embodiment will be described. The same parts as those in the first embodiment are denoted by the same reference numerals. The fall detection device 11 according to the present embodiment is the same as the first embodiment in that it is incorporated in a portable device such as a notebook personal computer (hereinafter referred to as a notebook personal computer), for example. It detects the acceleration in the upward direction and can perform protection processing on the equipment to be protected. · Especially when using a laptop computer on a desk, the power cable, LAN cable, and connection cables to various external devices are connected. If these cables are inadvertently pulled and the portable device falls, the fall time is shorter than a simple drop because the cable is pulled strongly first and has an initial velocity. For this reason, the fall detection device according to the first embodiment may not be able to perform protection processing because fall detection is not in time. Therefore, in the present embodiment, it is possible to detect that horizontal or upward acceleration that may lead to a drop is applied to the device to be protected, and to perform quicker processing.

That is, in the drop detecting device 11, two acceleration sensors 5 are arranged on the substrate 14 in addition to the plurality of drop sensors 3. The two acceleration sensors 5 are arranged such that their central axes are perpendicular to each other. In this embodiment, the board 14 is arranged horizontally and the acceleration sensor 5 is arranged in parallel with the surface of the board 14.

In this way, by configuring the center axis of the acceleration sensor 5 to be horizontal when the device to be protected is in use, the fall detection device 11 can detect acceleration applied in the horizontal and upward directions. it can. In this embodiment, one acceleration sensor 5 is arranged so that its central axis is parallel to the central axis of a housing of a notebook computer or the like to be protected. The acceleration sensor 15 has the same configuration as that of the acceleration sensor disclosed in Japanese Patent Application No. 2001-176640 filed earlier by the present applicant, for example. The acceleration sensor 5 has substantially the same shape as the above-mentioned fall sensor 3, but has a normal posture in which the central axis coincides with the horizontal axis and is in a stationary state by increasing the spring property of the movable contact. Sometimes, it is a so-called always-off type sensor in which the contact portion does not contact the container against the weight of the inertial body. In this state, the contact portion is separated from the inner surface of the container with a slight gap by balancing the radius by the weight of the inertial body, and when the equipment to be protected receives a large acceleration in the horizontal direction or When the apparent gravity of the inertial body increases due to acceleration, the contact part comes into contact with the metal container and turns on. In the present embodiment, for example, the movable contact is balanced so that it does not contact the fixed contact point at an acceleration of 1 G due to gravity, and the contact between the contacts is increased when the acceleration applied to the inertial body increases to 1.5 G or more. Has been.

Like the drop detector 1 according to the first embodiment, the drop sensor 3 opens the contact point when the apparent gravity decreases below a set value for a simple drop, and the drop sensor 3 opens its contact point. If it is determined that the signal processing circuit 100 has dropped or dropped from the duration or the like, a signal is input to the protection processing device to perform appropriate protection processing. Here, when the device to be protected is accelerated in the direction of water square, the gravity applied to the drop sensor 3 does not change. When the vehicle is accelerated upward, the apparent gravity increases, so that the drop sensor 3 maintains the contact state of the contact points.

However, the acceleration sensor 15 is always off type, and when a horizontal or upward acceleration is applied to the device to be protected, and when the acceleration exceeds a predetermined value, the contact is closed. For example, if the power cable is pulled and the device to be protected is subjected to a sudden acceleration that causes the device to fall, the acceleration sensor 5 closes the contact. Then, the signal processing circuit 100 that has received the signal from the acceleration sensor 5 outputs an acceleration detection signal, and the protection processing device that has received this signal performs appropriate protection processing. Also, if sudden acceleration is applied upward, In this case, similar detection and protection processing can be performed.

Normally, horizontal acceleration is not applied to the device to be protected, but vertical gravitational acceleration is applied. Therefore, the drop detector 11 is substantially more sensitive to the acceleration in the direction of gravity. However, while a device to be protected, such as a notebook computer, is used to move laterally on a desk or the like relatively frequently, it is rarely moved up and down. It also means that there is a danger of falling. Therefore, if the fall detecting device 11 is configured to more sensitively detect the acceleration due to the upward movement, it is possible to prepare for a danger of falling.

In the above embodiment, the two acceleration sensors 5 are arranged so that their central axes are orthogonal to each other, and these acceleration sensors 5 ′ are connected in parallel on a circuit, so that the devices to be protected can be protected. The acceleration applied to the front and rear and the acceleration applied to the left and right can be detected in the same way. On the other hand, for example, when the assumed horizontal acceleration direction is limited to left and right or front and rear, only one acceleration sensor 15 can be used. Furthermore, by arranging a plurality of acceleration sensors 15 while changing the angle of the central axis as in the case of the drop sensor 13, uniform characteristics can be provided in all directions in the horizontal plane.

FIG. 5 shows a third embodiment of the present invention, and different points from the second embodiment will be described. The same parts as those of the second embodiment are denoted by the same reference numerals.

For example, a lifeline has been used as a protective device for workers at high places, for example, to hold the worker's body and prevent it from falling. However, even with a lifeline, a fall accident still occurs.In recent years, impacts such as wearable airbags and auxiliary nets deployed around the workplace have been used to reduce the impact of a fall in a fall accident. Absorption aids have been proposed. The shock absorbing auxiliary device operates by receiving a fall detection signal from the fall detection device 21 worn by the worker to be protected, thereby allowing the worker to fall. It is possible to prevent lowering and reduce the impact when falling.

Therefore, the drop detecting device 21 according to the present embodiment is provided with a belt (corresponding to a mounting means) 7 for mounting on a worker. That is, as shown in FIG. 5, in the drop detecting device 21, a substrate 24 is housed in a case 6 attached to a belt 7. The fall detection device 21 is attached via a belt 7 near the center of the body, which is least susceptible to vibrations and acceleration / deceleration movements due to normal work, for example, near the waist of the worker.

If the fall detection device is attached to the worker's arm, not only will the fall detection device become an obstacle during the work, but acceleration and deceleration due to the movement of the arm will be repeated in any work, causing malfunction. A similar problem occurs when the fall detection device is attached to the worker's foot. On the other hand, in the case of the worker's torso, especially the lower back, which is the center of movement, sudden movement is unlikely to occur normally, and vibration and acceleration that may cause the drop sensor 3 to malfunction, including intentional cases. Is unlikely to be given. -When the drop detection device 21 is attached to the waist via the belt 7, the posture in which the substrate 24 arranged in the case 6 follows the body becomes the normal posture. That is, when the worker is in the upright state, the normal posture of the substrate 24 is almost vertical. Even if the substrate 24 is arranged in such a posture, the fall sensor 13 is arranged on the substrate 24 so that the normal operation range overlaps with at least one of the other fall sensors 3. At rest, at least one sensor 3 always has its contacts closed. Also, when the operator changes his posture, such as bending down or lying down, one drop sensor 3 always closes the contacts as described above.

When attaching the fall detector 21 to a worker at a high place, it is necessary to distinguish between the fall to be protected and other operations. For example, when you get off a small step with no danger, you will fall for a short time. In such a case, you do not need to operate the protective device. Therefore, also in this embodiment, the signal processing circuit 100 If the state does not continue for a predetermined time after all the signals are turned off, a fall signal is not output.

However, in the configuration of the above-described fall detection device 1, a malfunction may occur when jumping. For example, when the wearer jumps on the spot or jumps over a small step, the wearer is in a free fall state from when the foot leaves the ground until it reaches the ground again. Therefore, if this time exceeds a predetermined time, it is erroneously determined to be a fall. This is because the predetermined time is set on the assumption that the vehicle accelerates by free fall, such as jumping off a step or falling. In the case of a leap, deceleration is continued from the moment the foot is released from the ground to the highest point, and acceleration is continued until landing from the highest point. 'Therefore, even if the duration is the same, the movement distance is different, and the jump height itself is 1/4 of the fall distance when jumping down. Therefore, for example, even if the predetermined time is set so as not to operate when jumping off the step of lm, the off-time of the drop sensor 13 reaches the predetermined time by a jump of about 25 cm, and the vehicle falls into a falling state. It will be judged. Therefore, in the fall detecting device 21, the acceleration sensor 5 is used as a sensor for detecting a jump. In the acceleration sensor 5, when in the normal posture and in the stationary state, the contact portion is separated from the inner surface of the container with a slight gap by balancing the radius with the weight of the inertial body. When the apparent gravity of the inertial body increases due to the upward acceleration, the inertial body further deflects the contact portion to contact the metal container, and turns on the contact points. For example, in the second embodiment, the movable contact and the fixed contact are balanced so that they do not come into contact with each other at an acceleration of 1 G due to gravity. When the acceleration increases by 0.5 G or more, conduction is established between the contacts. ing.

When jumping, the body is accelerated against the gravity, and this acceleration and the gravitational acceleration are added to the acceleration sensor 5, so that the apparent weight of the humble body increases. Therefore, in the present embodiment, the acceleration sensor 5 is configured to be turned on when the apparent weight of the inertial body becomes 1.5 times. Signal from accelerometer 5 is signal processed When input to the circuit 100, the fall detection device 21 determines that the wearer has jumped and ignores the signal from the fall sensor 13 for a certain period of time so as not to perform signal processing. ing. Therefore, the free fall time due to jumping is ignored. If the falling state continues for longer than the free fall time due to jumping, the signal processing circuit 100 normally processes the signal from the drop sensor 5 to detect the fall, so that a protection operation must be performed. Can be. In this way, erroneous determination at the time of jump can be prevented. In addition, while the drop sensor 3 is arranged in plurality in consideration of the posture of the worker, only one acceleration sensor 5 is arranged. This is for the following reason. In other words, the worker may work while standing upright or close to that, and bend his hips or lie on his stomach. Therefore, it is necessary to operate any one of the drop sensors 3 for various postures of the worker. On the other hand, the worker's posture during the jump JS is upright or close to it, and jumping in a posture in which the body, especially the waist, etc., is extremely inclined or laid down is usually impossible. Therefore, basically, only one acceleration sensor 5 is required so that detection can be performed in the normal posture.

It is also possible to change the protection operation by estimating the height of the jump from the difference in acceleration when jumping, using a plurality of acceleration sensors with different operation accelerations. Further, when the allowable inclination angle of the sensor is smaller than the actual inclination angle of the mounting portion, a plurality of acceleration sensors may be provided.

Also, the drop sensor 13 and the acceleration sensor 5 used for the drop detectors 11 and 21 are designed to prevent the inertial body from applying excessive stress to the movable part as described for the drop detector 1. It is configured. As a result, the sensor itself will not be destroyed or the operating characteristics will not be offset if the device to be protected falls within a range that will not be destroyed, as well as the impact acceleration in normal handling. Therefore, for example, there is no problem even if the operator throws the fall detection device lightly with normal handling, and the fall sensor itself is broken while protecting the equipment to be protected in the event of a fall. No events will occur that could damage or offset the use of the protected equipment. Industrial applicability

As described above, the fall detection device according to the present invention is built in or attached to a portable device such as a notebook type personal convenience store or a protected object such as a worker at a high place, and detects a drop of the protected object by detecting the fall of the protected object. It is useful for activating the protection device.

Claims

The scope of the claims

1. Equipped with a plurality of drop sensors that detect that the acceleration in the direction of gravity has apparently decreased,

The drop sensor includes a metal cylindrical closed container, a movable contact provided in the closed container and having a plurality of contact portions disposed at equal intervals, and a movable contact provided on an inner peripheral surface of the closed container. A fixed contact that can be brought into contact with and separated from the movable container; and an inertial body that is housed in the closed container and that presses down the movable contact by its own weight to make contact with the fixed contact. In addition to having the same characteristics with respect to the direction, when the closed container is in a normal posture in which the central axis is the horizontal axis and is in a stationary state, the inertial body flexes the movable contact to contact the fixed contact, When the apparent weight of the inertial body has decreased to a predetermined value or less due to a drop or the like, the movable contact is separated from the fixed contact by staking the weight of the inertial body,

The plurality of drop sensors are at least one of the other drop sensors, and the inclination angle of the central axis of the closed container is made different from each other so that a part of the allowable inclination range with respect to the normal posture is overlapped. A drop detecting device, wherein the drop detecting device is disposed in the device.

2. In the fall detection device of claim 1,

An acceleration sensor that detects that the acceleration has increased,

The acceleration sensor includes a metal cylindrical closed container, a movable contact provided in the closed container and having a plurality of contact portions, and a movable contact provided on an inner peripheral surface of the closed container and capable of contacting and separating with the movable contact. A fixed contact, and an inertial body accommodated in the closed container and extending the movable contact by its own weight, wherein the movable contact of the acceleration sensor is piled on the weight of the inertial body when stationary, and the fixed contact is When the apparent weight of the inertial body increases due to an increase in the acceleration component in a direction perpendicular to the central axis of the sealed container by a predetermined value or more, the fixed contact comes into contact with the fixed contact. It is configured.

3. In the fall detection device of claim 2,

Comprising a plurality of the acceleration sensor,

The plurality of acceleration sensors are arranged on the same plane with different inclination angles of the central axis of the closed container so that at least one of the other acceleration sensors overlaps part of the allowable inclination range with respect to the normal posture. Have been.

4. In the fall detection device of claim 2,

Equipped with mounting means for mounting on the worker,

The mounting means is configured such that, when mounted on the worker in the standing state, the center axis of the acceleration sensor is a horizontal axis, and the acceleration in the direction of gravity due to jumping of the worker is detected. I have.