JP4005561B2 - Fall detection device - Google Patents

Description

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 a conventional drop detection sensor, a semiconductor type triaxial acceleration sensor having a high resolution with respect to input is often used because a change in acceleration to be detected is as small as 1 G or less.
The signal output from the acceleration sensor is amplified by an amplifier circuit, processed by an A / D converter, and then determined by a determination circuit.
[0001]
As described above, by processing the signal from the semiconductor triaxial acceleration sensor by the signal processing circuit 100, it is possible to determine the position change, the moving direction, the moving speed, and the like of the protection target device. And when it was judged from the result that it was falling the distance more than predetermined value, it was comprised so that a protection device might start.
[0002]
However, the semiconductor triaxial acceleration sensor has high accuracy and is expensive. Furthermore, it is necessary to provide one amplifier circuit and one A / D converter for processing the sensor output for each of the three axes, and the entire signal processing circuit becomes expensive. Therefore, it is inevitable that the entire fall detection device becomes 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 source, such as when a battery is used as a power source for portable use. For this reason, there is a problem that frequent charging and battery replacement are required.
[0003]
In addition, semiconductor sensors are vulnerable to excessive acceleration due to impact and require careful handling. For this reason, when it is adopted in a portable device, there has been a problem that the sensor output is offset by the impact at the time of dropping or the sensor itself is destroyed. Therefore, even if the device to be protected can be protected from falling, the sensor may malfunction after that, which may hinder the use of the device to be protected. There is also a problem in repeatedly using the fall detection device.
[0004]
Although it is conceivable to use a mechanical acceleration sensor as the fall sensor instead of the semiconductor sensor, most mechanical acceleration sensors cannot detect a change in gravity with sufficient accuracy. For example, a number of 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 disposed inside. However, in actuality, the fall sensor having the above configuration is difficult to manufacture and is not realistic. Also, if the biasing force in the direction of separating from each other is not always applied to the conductor or the electrode, 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. It will be maintained. For this reason, it does not function as a drop sensor. The above-described problem is not limited to the spherical type, and similarly occurs even in a unidirectional sensor in which a conductor is disposed on the electrode on the bottom surface of the container.
[0005]
Therefore, the fall sensor having the above-described configuration requires a configuration that constantly changes the contact state against gravity by an elastic body such as a spring. 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 applied by 1G gravity when stationary, and the apparent weight of the inertial body is reduced to a predetermined value by dropping or the like. When it is done, it must be configured to operate the contacts quickly.
[0006]
In particular, when the sensor is miniaturized, the mass of the inertial body is also reduced, so the elastic body that supports it needs to be flexible. Therefore, the smaller the sensor, the more difficult it is to design the sensor. Further, if the elastic body is made flexible, there arises a problem that the elastic body is easily deformed even by an impact acceleration applied by normal handling. For this reason, it is not possible to divert an acceleration sensor that detects, for example, horizontal vibration, to a fall sensor that detects acceleration in the gravitational direction by simply placing it horizontally, for example, in terms of the strength setting and durability of the elastic body. difficult.
[0007]
Furthermore, it is conceivable to use a unidirectional mechanical acceleration sensor with a simple structure as the fall sensor. However, in order to detect the fall of the device to which the sensor is attached in all postures, it is necessary to arrange many sensors three-dimensionally with respect to the substrate so as to have sensitivity in all directions. This complicates the arrangement of parts and makes it difficult to manufacture.
[0008]
SUMMARY OF THE INVENTION An object of the present invention is to provide a drop detection device that can accurately detect a drop of a target device in any posture and that has a simple configuration and excellent impact resistance.
Disclosure of the invention
The drop detection device of the present invention is provided on a metal cylindrical sealed container, a movable contact provided in the sealed container and having a plurality of contact portions arranged at equal intervals, and an inner peripheral surface of the sealed container. A plurality of mechanical drop sensors including a fixed contact that can be brought into and out of contact with the movable contact, and an inertial body that is housed in the sealed container and presses the movable contact by its own weight to contact the fixed contact. Yes. The drop sensor has the same characteristics in all directions around the central axis of the cylindrical sealed container, and the inertial body is in a normal posture in which the central axis of the sealed container is a horizontal axis and is stationary. When the apparent weight of the inertial body decreases below a predetermined value due to dropping or the like, the movable contact is fixed against the weight of the inertial body. Configured to be away from the contacts The movable contact and the fixed contact have an allowable inclination range with respect to the horizontal axis of the central axis of the sealed container in which contact and separation are normally performed. The For this reason, the plurality of fall sensors are at least one of the other fall sensors. Said So that part of the allowable inclination range overlaps Respectively Of the central axis of the sealed container Against the horizontal axis Arrange on the same plane with different inclination angles At the same time, by making these fall sensors all connected in parallel, the output of the parallel circuit is turned on when in the stationary state, and the apparent weight of the inertial body is reduced below a predetermined value. Because it will turn off when Even if the protection target device is in any posture, it is possible to detect the fall with high accuracy. In addition, since the drop sensor has the same characteristics in all directions around the central axis of the sealed container, the number of drop sensors to be used can be reduced compared to the case of using a unidirectional drop sensor. . In addition, since a plurality of drop sensors can be arranged on the same plane, the configuration and manufacture are simplified.
BEST MODE FOR CARRYING OUT THE INVENTION
In order to describe the present invention in more detail, it will be described with reference to the accompanying drawings. First, FIGS. 1 to 3 show a first embodiment of the present invention. As shown in FIG. 1, the fall detection device 1 according to the present embodiment includes a signal processing circuit 100 composed of a plurality of components, a plurality of fall sensors 3, and the like disposed on a substrate 4 housed in a protection target device 2. Has been configured. The fall sensor 3 is a small acceleration sensor, and has substantially the same configuration as the acceleration sensor disclosed in Japanese Patent Application Laid-Open No. 2001-194382 and Japanese Patent Application No. 2001-256194 filed earlier by the applicant.
[0009]
FIG. 2 is a longitudinal sectional view of the drop sensor 3, and FIG. 3 is a sectional view taken along the line 3-3 in FIG. As shown in FIGS. 2 and 3, the drop sensor 3 includes a sealed container 101 including a bottomed cylindrical metal container 31 and a cover plate 32 that is airtightly fixed to the opening thereof. In the present embodiment, the outer diameter of the sealed container 101 is set to 3.3 mm, and the length is set to 6.2 mm. The inner peripheral surface 31A of the metal container 31 is a fixed contact. The lid plate 32 includes a metal plate 32B having a through hole 32A, and a rod-like conductive terminal 33 that is airtightly inserted and fixed to the through hole 32A with an electrical insulating material 34 such as glass.
[0010]
A metal movable contact 35 having a plurality of movable portions 35A having spring properties is conductively fixed to the tip of the conductive terminal 33 inside the container 31. In the planar state before assembly, the movable contact 35 is configured such that the movable portion 35A extends radially from the center thereof. The movable contact 35 is fixed to the conductive terminal 33 by welding and fixing the contact plate 39 to the conductive terminal 33 with the center portion sandwiched between the end face of the conductive terminal 33 and the metal contact plate 39. Has been. Further, the movable portion 35A is bent and held at a predetermined angle with respect to the center of the movable contact 35 by sandwiching the movable contact 35 between the contact plate 39 and the resin insulating holder 38.
[0011]
In the present embodiment, when the movable portion 35A is in a free state without an inertial body 36, which will be described later, the movable portion 35A is along the longitudinal direction (the left-right direction in FIG. 2) of the inner peripheral surface 31A of the container 31 and at equal intervals in the circumferential direction. Be placed. The tip of each movable portion 35A is bent toward the inner peripheral surface 31A side of the container 31 to form a contact portion 35B. With the above configuration, the movable portion 35A is in contact with the inner peripheral surface 31A of the metal container 31 that is a fixed contact at the tip of the contact portion 35B. Therefore, the contact portion 35B comes into contact with the inner peripheral surface 31A in a small area close to a point contact, so that the contact pressure increases, and contact failure does not occur due to dirt on the container inner peripheral surface 31A.
[0012]
A metal inertial body 36 is disposed inside the container 31. In the present embodiment, the inertia body 36 has a diameter of 2.4 mm. The drop sensor 3 has a normal posture when it is arranged so that the central axis of the metal container 31 (sealed container 101) is a horizontal axis. When the drop sensor 3 is placed in a normal posture and is stationary, the inertial body 36 pushes down the movable portion 35A while being bent by its own weight, thereby bringing the contact portion 35B onto the inner peripheral surface 31A of the metal container 31. Make contact. Therefore, normally, the metal container 31 and the conductive terminal 33 are electrically connected. An electrical insulator 37 such as resin is disposed on the closed bottom surface of the metal container 31. Thereby, when the contact part 35B leaves | separates from the container inner surface 31A, between the movable contact 35 and the metal container 31 is prevented from being in a conduction state through the inertial body 36. Inertia 3 6 Cover the surface with an electrical insulator, 6 The electrical insulator 37 can be omitted when the whole is made of an electrical insulator.
[0013]
The movable contact 35 is composed of a very thin conductive metal plate, in the embodiment, a phosphor bronze plate having a thickness of 12 μm. Therefore, if it is repeatedly sandwiched between the inertia body 36 and the inner surface of the container, there is a possibility of causing deformation due to extension. Further, when the drop sensor 3 receives impact acceleration and the inertial body 36 comes into contact with the vicinity of the sandwiched portion between the insulating holding body 38 and the contact plate 39 in the movable contact 35, the movable contact 35 can be plastically deformed beyond the elastic deformation region. There is sex. Therefore, in this embodiment, the insulating holding body 38 is provided with the protruding portion 38A. As a result, even if the inertial body 36 moves to the contact plate 39 side, the inertial body 36 abuts against the protrusion 38 </ b> A and therefore does not hit the vicinity of the holding portion of the movable contact 35 by the holding portion 38 and the contact plate 39. For this reason, even when the drop sensor 3 receives impact acceleration, the inertial body 36 does not apply excessive stress to the movable portion 35A, and plastic deformation of the movable contact 35 and associated characteristic changes can be prevented.
[0014]
A plurality of columnar portions 31 </ b> B are provided at equal intervals on the inner peripheral surface 31 </ b> A of the metal container 31. The columnar portion 31 </ b> B protrudes in a columnar shape inside the container 31. As shown in FIG. 3, the size and height of the adjacent columnar portions 31B are set so that the inertial body 36 does not reach the inner peripheral surface 31A of the container 31 when the inertial body 36 and the columnar portion 31B come into contact with each other. ing. Further, the movable portion 35A of the movable contact 35 is disposed between the adjacent columnar portions 31B. Thereby, even when the movable portion 35A and the inertial body 36 are in contact with each other, a gap is always generated between the inner surface 31A of the container 31 and the inertial body 36. For this reason, it is possible to prevent the extension of the movable portion 35A and the accompanying deformation and characteristic change even during long-term use. As described above, the drop sensor 3 according to the present embodiment uses a semiconductor type acceleration sensor because of its structure, without causing a characteristic change even with respect to impact acceleration given by normal handling or long-term use. No special handling like things is required.
[0015]
In the drop sensor 3, the apparent weight of the inertial body 36 is reduced when the fall sensor 3 is in a fall state, so the movable portion 35 </ b> A that has been bent pushes the inertial body 36 back to the central portion of the container 31 and the inner peripheral surface of the container 31. Release contact with 31A. Therefore, conduction between the metal container 31 and the conductive terminal 33 is interrupted. In this way, the drop sensor 3 can reliably switch the contact state when it falls.
[0016]
In order for the fall 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 35A is sufficiently bent by the inertial body 36 so that the inside of the metal container 31 It must be brought into contact with the peripheral surface 31A. For example, when the center axis of the drop sensor 3 is tilted by a predetermined angle or more with respect to the horizontal axis, the inertial body 36 comes into contact with the bottom surface of the container 31 and the weight thereof does not work sufficiently in the direction to bend the movable portion 35A. . For this reason, the contact portion 35B is separated from the inner peripheral surface 31A by a slight change in gravity due to the vertical movement, and conduction is cut off. Further, when the inclination of the central axis of the drop sensor 3 is increased, the inertial body 36 is moved toward the center of the container 31 by the movable part 35A, so that the contact part 35B does not contact the metal container 31 regardless of the magnitude of gravity. Therefore, with only one drop sensor 3, there is no problem when it is tilted about the central axis of the container 31, but there is a possibility of malfunctioning when the central axis is tilted.
[0017]
Therefore, the drop detection device 1 is configured such that the plurality of drop sensors 3 are arranged on the substrate 4 and the central axes of the containers 31 of the plurality of drop sensors 3 are located on the same plane. In addition, the fall sensor 3 changes the tilt angle within the allowable tilt angle so that at least one of the other drop sensors 3 overlaps the normal operation range at the upper and lower limits of the permissible operation range of each drop sensor 3. While being arranged.
[0018]
With the above configuration, for example, when the drop detection device 1 is arranged in a protection target device such as a notebook computer so that the substrate 4 is horizontal, the central axes of all the drop sensors 3 are horizontal. For this reason, all the drop sensors 3 close their contacts when stationary, and all the drop sensors 3 open their contacts when dropped. Each drop sensor 3 is cylindrical and has uniform characteristics in all directions with respect to the central axis thereof, so that the angle of the substrate 4 can be set with an arbitrary axis parallel to the surface of the substrate as a rotation axis. Even when it is changed, the inclination of at least one central axis of the drop sensor 3 with respect to the horizontal axis is within an allowable error.
[0019]
Therefore, even when the device to be protected is used in an inclined state, or when the substrate is disposed in an inclined state or a vertical state, at least one drop sensor 3 can always keep the contact point in contact in a stationary state. As well as being able to perform normal operation against dropping. In addition, since the drop sensor 3 has the same characteristics in all directions with respect to the central axis, the front and back of the sensor 3 and the inclination in the horizontal direction do not matter when arranged on a substrate or the like, only the direction of the central axis. If it is considered, it will be easy to handle. In the case of using a unidirectional mechanical acceleration sensor, it is necessary to arrange the sensor in a three-dimensional arrangement in order to have sufficient sensitivity in all directions centered on three axes. In the case of the drop sensor 3, the central axes can be aligned on the same plane, and the manufacture becomes easy.
[0020]
All of the drop sensors 3 are arranged in parallel on the circuit to form an OR circuit, so that an on signal can always be input to the signal processing circuit 100 when it is stationary. As described above, when the fall detection device 1 is in the fall state and the apparent gravity is reduced, the drop sensor 3 in the normal posture is configured such that the movable part 35A pushes the inertial body 36 back to the center of the container 31 and the contact part 35B is made of metal. Since it is away from the container 31, the output is reliably turned off. Further, the drop sensor 3 that is tilted beyond the allowable tilt range opens the contact point earlier than the drop sensor 3 in the normal posture because the weight of the inertial body 36 is dispersed without being perpendicular to the movable portion 35A. Or the contact remains open from the beginning. When the signals from all the drop 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 3 does not need to be amplified or A / D converted, the signal processing circuit 100 is simpler than the case of using a semiconductor sensor and can reduce power consumption. . For this reason, for example, even when the power source is a battery, it can be used for a long time.
[0021]
By the way, the drop sensor 3 is a switch structure having a contact point at the same time as being very sensitive to a change in gravity. For this reason, there is a case where the inertial body 36 swings and repeats opening and closing of the contact even with vibration due to normal use of the device to be protected, and it may be erroneously determined to fall due to such an off signal.
[0022]
Therefore, the signal processing circuit 100 of the fall detection device 1 does not simply look at the off state of the fall sensor 3, but performs a protection operation based on whether or not the state where the signal from the fall sensor 3 is off has reached a predetermined time. Judgment whether or not to perform. In other words, even if the signal from the drop sensor 3 is once turned off, if it is turned on within a predetermined time, it is determined that the vibration does not cause a problem due to normal use. On the other hand, when the signal from the drop sensor 3 is turned off after a predetermined time, it is determined that the drop state continues and the drop is at a height that requires protection. Then, appropriate protection processing is performed on the protection target device by temporarily stopping, for example, data recording work of the protection target device or turning off the power. Further, by filtering the signals from the respective drop sensors 3 individually, a protection circuit is provided so that a noise signal with an extremely short interval where the contact contact state that occurs during the movement of the inertial body 36 is unstable is not detected. Can be prevented from malfunctioning and malfunctioning.
[0023]
FIG. 4 shows a second embodiment of the present invention, and the differences from the first embodiment will be described. The same parts as those in the first embodiment are denoted by the same reference numerals. The drop 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). It is also possible to detect the acceleration of the object and to perform protection processing of the device to be protected.
[0024]
In particular, when using a notebook computer or the like on a desk, a power cable, a LAN cable, and connection cables to various external devices are connected. When these cables are inadvertently pulled and the portable device falls, the drop time is shorter than a simple drop because the cable is initially pulled strongly and has an initial speed. For this reason, in the fall detection apparatus according to the first embodiment, there is a possibility that the fall detection cannot be performed in time and the protection process cannot be performed. Therefore, in this embodiment, it is possible to perform a quicker process by detecting that a horizontal or upward acceleration that may cause a fall is applied to the device to be protected.
[0025]
That is, in the fall detection device 11, two acceleration sensors 5 are arranged in addition to the plurality of fall sensors 3 with respect to the substrate 14. The two acceleration sensors 5 are arranged so that their center axes are perpendicular to each other. In this embodiment, the substrate 14 is disposed horizontally and the acceleration sensor 5 is disposed in parallel on the surface of the substrate 14.
[0026]
Thus, the fall detection device 11 can detect the acceleration applied in the horizontal direction and the upward direction by configuring the central axis of the acceleration sensor 5 to be horizontal when the protection target device is in use. In this embodiment, one acceleration sensor 5 has a central axis arranged in parallel with a central axis of a case such as a notebook personal computer to be protected.
[0027]
The acceleration sensor 5 has, for example, the same configuration as the acceleration sensor disclosed in Japanese Patent Application No. 2001-176401 filed earlier by the present applicant. The acceleration sensor 5 has substantially the same shape as the drop sensor 3 described above, but when the movable contact is highly springy, the center axis is in a normal posture that coincides with the horizontal axis and is stationary. Is a so-called always-off sensor in which the contact portion does not contact the container against the weight of the inertial body. In this state, the contact portion balances the amount of deflection with the weight of the inertial body and is separated from the inner surface of the container with a slight gap, so that the device to be protected receives a large acceleration in the horizontal direction or acceleration in the gravity direction. When the apparent gravity of the inertial body increases, the contact portion comes into contact with the metal container and is turned on. In this embodiment, for example, the 1 G acceleration due to gravity is balanced so that the movable contact does not come into contact with the fixed contact. When the acceleration applied to the inertial body increases to 1.5 G or more, the contact is made conductive. Yes.
[0028]
As with the fall detection device 1 according to the first embodiment, the fall detection device 11 opens its contact point when the apparent gravity decreases below a set value for a simple fall, and the continuation thereof. If it is determined that the signal processing circuit 100 is dropped due to time or the like, an appropriate protection process is performed by inputting a signal to the protection processing apparatus. Here, when the device to be protected is accelerated in the horizontal direction, the gravity applied to the drop sensor 3 does not change. Further, when the acceleration is applied in the upward direction, the apparent gravity increases, so that the fall sensor 3 maintains the contact state of the contacts.
[0029]
However, the acceleration sensor 5 is always off-type, and when the acceleration in the horizontal direction or the upward direction is applied to the device to be protected and this exceeds a predetermined value, the contact is closed. For example, the acceleration sensor 5 closes the contact point when a power cable or the like is pulled and the device to be protected receives a rapid acceleration that causes the device to fall. The signal processing circuit 100 that receives the signal from the acceleration sensor 5 outputs an acceleration detection signal, and the protection processing device that receives this signal performs appropriate protection processing. The same detection and protection process can be performed when a sudden acceleration is applied in the upward direction.
[0030]
Normally, no acceleration in the horizontal direction is applied to the device to be protected, and a vertical acceleration of gravity is applied. Accordingly, the fall detection device 11 is substantially more sensitive to acceleration in the direction of gravity. However, while using a protected device such as a notebook computer, it is relatively frequent to move horizontally on a desk, etc., but it rarely moves up and down, and if the position of the device moves up. It also means that there is a risk of falling. Therefore, if the fall detection device 11 is configured to detect the acceleration caused by the upward movement more sensitively, it is possible to prepare for the danger of dropping.
[0031]
Further, in the above embodiment, the two acceleration sensors 5 are arranged so that the central axes thereof are orthogonal to each other, and these acceleration sensors 5 are connected in parallel on the circuit, so that they are applied to the protection target device in the front-rear direction. The acceleration and 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 the left and right or front and rear, the acceleration sensor 5 can be integrated. Furthermore, by arranging a plurality of acceleration sensors 5 while changing the angle of the central axis in the same manner as the drop sensor 3, uniform characteristics can be given to all directions of the horizontal plane.
[0032]
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 in the second embodiment are denoted by the same reference numerals.
Conventionally, for example, a lifeline that holds a worker's body and prevents the fall is used as a protective tool for an operator at a high place. However, even with lifelines, falling accidents still occur, and in recent years, shock absorption assistance such as wearable airbags and auxiliary nets deployed around the workplace to ease the impact of falling in a falling accident Instruments have been proposed. The shock absorbing auxiliary device operates in response to a drop detection signal from the drop detection device 21 worn by the worker to be protected, thereby preventing the worker from dropping or mitigating the shock at the time of dropping. be able to.
[0033]
Therefore, the drop detection device 21 according to the present embodiment is configured to include a belt (corresponding to a mounting means) 7 for mounting on an operator. That is, as shown in FIG. 5, the drop detection device 21 has a substrate 24 housed in a case 6 attached to the belt 7. The fall detection device 21 is attached via a belt 7 near the center of the body, for example, near the waist of the operator, which is most unlikely to be affected by vibration or acceleration / deceleration movement caused by normal work.
[0034]
When the fall detection device is attached to the operator's arm, the fall detection device not only interferes with the work but also causes a malfunction because acceleration / deceleration accompanying the movement of the arm is repeated in every work. The same problem occurs when the fall detection device is attached to the operator's foot. On the other hand, in the case of the operator's torso, especially the waist that is the center of movement, sudden movements are unlikely to occur normally, and vibrations and accelerations that cause the fall sensor 3 to malfunction including intentional cases are given. It is unlikely to be done.
[0035]
When the fall detection device 21 is attached to the lower back via the belt 7, the posture of the substrate 24 disposed in the case 6 along the body is a normal posture. That is, when the worker is in an upright state, the normal posture of the substrate 24 is almost vertical. Even if the substrate 24 is arranged in such a posture, the drop sensor 3 is arranged on the substrate 24 so that the range of normal operation overlaps with at least one of the other drop sensors 3, so at least in the stationary state. The contact of one sensor 3 is always closed. Also, when the operator changes his / her posture such as bending down or lying down, the contact point of one drop sensor 3 is always closed as described above.
[0036]
When the fall detection device 21 is mounted on an operator at a high place, it is necessary to distinguish between a fall to be protected and other operations. For example, when descending a small step with no danger, it falls for a short time, but in such a case, it is not necessary to operate the protective device. Therefore, also in this embodiment, the signal processing circuit 100 is configured so as not to output a fall signal unless all the signals from the fall sensor 3 are turned off for a predetermined time.
[0037]
However, the above-described configuration of the drop detection device 1 may cause a malfunction when jumping. For example, when the wearer jumps on the spot or jumps over a small level difference, the user is in a free fall state from when the foot leaves the ground until landing again. Therefore, if this time exceeds a predetermined time, it is erroneously determined as falling. This is because, for example, the predetermined time is set on the assumption that the vehicle is accelerated by free fall, such as jumping down or falling off a step. In the case of jumping, the vehicle continues to decelerate from the moment the foot leaves the ground until the highest point is reached, and continues to accelerate until it reaches the highest point. Therefore, even if the duration is the same, the moving distance is different, and the jump height itself becomes 1/4 with respect to the falling distance when jumping. Therefore, for example, even if a predetermined time is set so that it does not operate when jumping down a step of 1 m, it is determined that the off time of the drop sensor 3 has reached a predetermined time due to a jump of about 25 cm and has fallen into a falling state. It will be.
[0038]
Therefore, in the fall detection device 21, the acceleration sensor 5 is used as a sensor for detecting jumping. In the acceleration sensor 5, when in a normal posture and in a stationary state, the contact portion balances the amount of bending with the weight of the inertial body and is separated from the inner surface of the container with a slight gap. When the apparent gravity of the inertial body increases due to the acceleration in the upward direction, the inertial body further deflects the contact portion to contact the metal container, and the contacts are turned on. For example, in the second embodiment, the balance is made so that the movable contact and the fixed contact do not come into contact with each other at 1 G acceleration due to gravity, and the contacts are brought into conduction when the acceleration increases by 0.5 G or more.
[0039]
When jumping, the body is accelerated against gravity, so both the acceleration and the gravitational acceleration are added to the acceleration sensor 5, and the apparent weight of the inertial body increases. Therefore, in this embodiment, the acceleration sensor 5 is configured to be in the on state when the apparent weight of the inertial body becomes 1.5 times. When the signal from the acceleration sensor 5 is input to the signal processing circuit 100, the fall detection device 21 determines that the wearer has jumped and ignores the signal from the fall sensor 3 for a certain period of time and does not perform signal processing. It is configured as follows. For this reason, the free fall time by jumping is disregarded. When the fall state continues beyond the free fall time due to jumping, the signal processing circuit 100 normally processes the signal from the drop sensor 5 and detects the fall, so that a protection operation can be performed. Thus, erroneous determination at the time of jumping can be prevented.
[0040]
Note that a plurality of drop sensors 3 are arranged in consideration of the posture of the operator, while 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 it, bending his / her waist greatly, or becoming hungry. For this reason, it is necessary to operate any one of the drop sensors 3 with respect to various postures of the worker. On the other hand, the posture of the worker at the time of jumping is an upright posture or a posture close to it, and jumping in a posture where the body, particularly the waist is extremely inclined or lying down, is usually impossible. Therefore, basically only one acceleration sensor 5 is required so that detection in a normal posture is possible.
[0041]
In addition, by using a plurality of acceleration sensors with different operation accelerations, it is possible to estimate the height of jumping from the difference in acceleration at the time of jumping and change the protection operation. Further, when the allowable inclination angle of the sensor is smaller than the inclination angle of the mounting portion that can actually occur, a plurality of acceleration sensors may be provided.
[0042]
Further, the fall sensor 3 and the acceleration sensor 5 used in the fall detection devices 11 and 21 are configured so that the inertial body does not apply excessive stress to the movable part, as described in the fall detection device 1. As a result, in addition to impact acceleration in normal handling, the sensor will not be destroyed or an operational characteristic offset will not occur if it falls within a range where the protection target device itself is not destroyed. For this reason, for example, there is no problem even if the worker throws the fall detection device lightly with normal handling, and the fall sensor itself is destroyed or offset while protecting the protection target device during the fall. There will be no situation that would impede the use of protected equipment.
Industrial applicability
As described above, the fall detection device according to the present invention is protected by detecting the fall of the protection object built in or attached to the protection object of a portable device such as a notebook personal computer or an aerial worker. It is useful for starting up the device.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of a fall detection device according to a first embodiment of the present invention,
Figure 2 is a vertical side view of the drop sensor.
3 is a longitudinal sectional view taken along line 3-3 of the drop sensor shown in FIG.
FIG. 4 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.
FIG. 5 is a view corresponding to FIG. 1 showing a third embodiment of the present invention.

Claims (4)

It has multiple drop sensors that detect that the acceleration in the direction of gravity is apparently reduced,
The drop sensor includes a metal cylindrical sealed container, a movable contact provided in the sealed container and having a plurality of contact portions arranged at equal intervals, and the movable contact provided on an inner peripheral surface of the sealed container. A fixed contact that can be brought into and out of contact with the stationary contact, and an inertial body that is housed in the sealed container and that presses the movable contact by its own weight to bring it into contact with the fixed contact. The inertial body bends the movable contact to contact the fixed contact when it is in a normal posture where the central axis of the sealed container is a horizontal axis and in a stationary state. the weight of the apparent of the inertial body when decreased below a predetermined value is configured such that the movable contact against the weight of the inertial body is separated from the fixed contact, and the movable contact and the fixed contact Away has a permissible inclination range for the horizontal axis of the central axis of the closed container to be carried out normal,
Wherein the plurality of drop sensors are arranged on the same plane with different inclination angle with respect to the horizontal axis of the central axis of each said sealed container so that a portion of at least one and the allowable slope range of the other fall sensor overlap In addition, by making these drop sensors all connected in parallel, the output of the parallel circuit is turned on in the stationary state, and the apparent weight of the inertial body is reduced below a predetermined value. fall detection device according to claim off with a Rukoto when. Having an acceleration sensor for detecting the presence of a pressurized speed increases,
The acceleration sensor includes a metal cylindrical sealed container, a movable contact provided in the sealed container and having a plurality of contact portions, and a fixed contact that is provided on an inner peripheral surface of the sealed container and is capable of contacting and leaving the movable contact. And an inertial body that is housed in the sealed container and deflects the movable contact by its own weight, and the movable contact of the acceleration sensor is not in contact with the fixed contact against the weight of the inertial body when stationary. becomes in contact, the acceleration component in the vertical direction with respect to the central axis of the closed container when the weight of the apparent of the inertial body increases above a predetermined value has increased configured to contact with the fixed contact, wherein The fall detection device according to claim 1, further comprising an allowable inclination range with respect to a horizontal axis of a central axis of the sealed container in which the movable contact and the fixed contact are normally contacted and separated . Includes a plurality of pre-Symbol acceleration sensor,
Wherein the plurality of acceleration sensors are arranged with different angle of inclination relative to the horizontal axis of the central axis of each said sealed container so that a portion of at least one and the allowable slope range of the other acceleration sensors overlap on the same plane The fall detection device according to claim 2, wherein: Equipped with a mounting means for mounting to create skilled in the art,
Said mounting means, when mounted on a worker in the raised standing state, the acceleration sensor center axis becomes the horizontal axis of, that is configured to detect the acceleration in the gravity direction due to jumping of the worker The fall detection device according to claim 2 .

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