JP4553353B2 - Approach warning device - Google Patents

Description

  The present invention relates to an approach warning device. More specifically, the present invention uses an UWB (Ultra Wide Band) technology to detect and alert the worker to approach the charging unit when working around an electrical facility that may cause an electric shock, for example. It relates to an approach warning device.

  When working with special high-voltage / high-voltage electrical equipment, it is necessary to prevent workers from accidentally approaching and contacting the live parts due to carelessness or misunderstanding. For this reason, a voltage detector has been conventionally used. In other words, the voltage detector operates by electrostatic induction due to the voltage applied to the electrical equipment. In such a case, the voltage detector is activated and a lamp or buzzer attached to a helmet or safety shoes is activated to issue an alarm.

An example of a helmet incorporating a voltage detector is disclosed in Japanese Patent Application Laid-Open No. 11-012842. As shown in FIGS. 9 to 11 , this helmet has tape-like detection electrode portions 102 a and 102 b attached to the helmet body 101 and a non-contact type voltage detector 103. The detection electrode parts 102a and 102b are crossed at the rear part of the helmet body 101 and are electrically connected. The detection electrode unit 102 a is connected to the input end of the non-contact type voltage detector 103. Further, an LED 105 is connected to the output end of the non-contact type voltage detector 103 by a lead wire 104. Further, a buzzer 111 described later is also attached to the helmet body 101.

In FIG. 11 , reference numeral 106 denotes a voltage level detection unit connected to the detection electrode unit 102a serving as a tip detection unit. The voltage level detection unit 106 uses the potential with the target electric wire detected by the detection electrode unit 102a for sensitivity adjustment. When the potential set by the resistor 107 exceeds the potential, an output signal is transmitted. The flicker generator 108 that has received the output signal from the voltage level detector 106 outputs a flicker signal, and the acoustic frequency oscillator 109 outputs an acoustic frequency signal. As a result, the display (LED) 110 is flickered, the buzzer 111 sounds, and an alarm is given to the worker.

JP-A-11-012842 JP 09-191905 A

  However, the method using a voltage detector can only detect electrostatic induction at a site where the voltage detector is attached. For this reason, even if the worker wears a helmet or safety shoes with a built-in voltage detector, when the arm is extended, for example, the fingertip may approach the charging part beyond the approach limit distance, It was not possible to cope with such a case.

  In addition, a voltage detector using electrostatic induction has a problem in that the electric field strength is not stable due to the influence of the shape and position of the charging unit, and the detection accuracy of the approach distance varies due to the principle.

  Furthermore, since the electric field strength at which the voltage detector operates cannot be adjusted, it is necessary to use different voltage detectors depending on the voltage class of the electric equipment to be detected. In addition, when the target voltage is increased, the voltage detector becomes larger, which hinders wearing such as being unable to be built in a helmet or the like, and worsens workability.

  An object of this invention is to provide the approach warning apparatus which can measure the approach distance in the site | part nearest to a charging part. It is another object of the present invention to provide an approach alarm device that is excellent in approach distance measurement accuracy and can be miniaturized.

In order to achieve the above object, the approach warning device according to claim 1 calculates the approach distance of the worker based on the transmission timing of the impulse signal and the reception timing of the reflected wave of the impulse signal, and the approach distance and storage means. The approach distance detection means for superimposing and transmitting the approach limit distance stored in advance on the impulse signal, and attached to the member worn by the operator , receiving the impulse signal, and the approach distance is shorter than the approach limit distance The approaching distance detecting means is installed at a position affected by the magnetic flux change of the charging unit, and is operated by an induced current due to electromagnetic induction.

  The approach distance detecting means has a distance measuring function by transmission / reception of an impulse signal and a communication function by transmitting data superimposed on the impulse signal. Since the distance measurement function uses the reflection of the impulse signal hitting the worker, the distance to the worker (approach distance of the worker) can be measured as the distance to the worker's closest part. The approach distance detecting means transmits the approach distance obtained by the distance measuring function and the preset approach limit distance to the alarm means by the communication function. The alarm means restores the approach distance data and the approach limit distance data from the received impulse signal and compares them. Then, when the approach distance is shorter than the approach limit distance, that is, when the worker approaches the charging unit beyond the approach limit distance, an alarm is issued to alert the worker.

The approach warning device according to claim 2 calculates the approach distance of the worker based on the transmission timing of the impulse signal and the reception timing of the reflected wave of the impulse signal, and stores the approach distance and the storage means in advance. Compared with the approach limit distance, when the approach distance is shorter than the approach limit distance, the approach distance detection means that superimposes and transmits an alarm signal on the impulse signal, and is attached to the member worn by the worker and receives the impulse signal And an alarm means that operates upon reception of an alarm signal. The approach distance detection means is installed at a position that is affected by a change in the magnetic flux of the charging unit, and is operated by an induced current caused by electromagnetic induction.

  The approach distance detecting means has a distance measuring function by transmission / reception of an impulse signal and a communication function by transmitting data superimposed on the impulse signal. In the distance measuring function, since the impulse signal is reflected on the worker and reflected, the distance between the worker and the nearest part can be measured as the worker's approach distance. The approach distance detecting means compares the worker's approach distance obtained by the distance measuring function with a preset approach limit distance. When the approach distance is shorter than the approach limit distance, that is, when the worker approaches the charging unit beyond the approach limit distance, an alarm signal is transmitted to the alarm means by the communication function. The warning means issues a warning when the warning signal is superimposed on the received impulse signal, and alerts the operator.

The approach warning device according to claim 3 calculates the approach distance of the worker based on the transmission timing of the impulse signal and the reception timing of the reflected wave of the impulse signal, and transmits the approach distance superimposed on the impulse signal. The approach distance detection means is attached to a member worn by the operator, receives an impulse signal, compares the approach distance with the approach limit distance stored in advance in the storage means, and the approach distance is shorter than the approach limit distance. The approaching distance detecting means is installed at a position affected by the magnetic flux change of the charging unit, and is operated by an induced current due to electromagnetic induction.

  The approach distance detecting means has a distance measuring function by transmission / reception of an impulse signal and a communication function by transmitting data superimposed on the impulse signal. In the distance measuring function, since the impulse signal is reflected on the worker and reflected, the distance between the worker and the nearest part can be measured as the worker's approach distance. The approach distance detecting means transmits the approach distance of the worker obtained by the distance measuring function to the alarm means by the communication function. The alarm means restores the approach distance data from the received impulse signal and compares it with the preset approach limit distance. Then, when the approach distance is shorter than the approach limit distance, that is, when the worker approaches the charging unit beyond the approach limit distance, an alarm is issued to alert the worker.

Also, proximity warning apparatus of the present invention, since the alarm means is operator is attached to the member to be mounted, can be operator alarm means always carry.

In the approach warning device according to claim 4 , the approach distance detecting means is directly attached to the charging unit. Therefore, the approach distance to the approach distance detecting means and the approach distance to the charging unit can be matched.

  Thus, since the approach warning device according to the first aspect is configured as described above, the approach distance at the part closest to the approach distance detecting means of the worker can be measured. For example, when the hand is extended toward a certain direction of the approach distance detection means, the distance from the fingertip can be measured. For this reason, the approach distance of the worker can be accurately measured. For example, even when the worker extends only his / her hand without moving the place, an alarm can be issued to alert the worker. In addition, the distance measurement function based on the transmission and reception of impulse signals is highly accurate in principle, and the distance can be measured without being affected by the electric field strength that changes depending on the shape and position of the charging unit. Can be measured stably with high accuracy, and a reliable alarm can be performed. Furthermore, since the alarm means receives the impulse signal transmitted by the approach distance detection means and issues an alarm, the alarm means can be reduced in size as compared with the voltage detector, and provides an alarm means convenient for mounting on the operator. Can do. And by setting the approaching limit distance according to the voltage class of the charging unit in advance, it is possible to deal with electrical equipment of various voltage classes and to provide an approach alarm device with excellent versatility. .

  The same effects can be obtained with the approach alarm device according to claim 2 and the approach alarm device according to claim 3.

Further, in the approach warning device of the present invention , the warning means is attached to the member worn by the worker, so that the warning means can be easily carried and the warning means can always be carried without obstructing the work. .

Further, in the approach warning device according to claim 4 , since the approach distance detecting means is directly attached to the charging unit, the approach distance to the approach distance detecting means coincides with the approach distance to the charging part, and It becomes easy to measure the approach distance (separation distance from the charging unit) more accurately.

  Hereinafter, the configuration of the present invention will be described in detail based on the best mode shown in the drawings.

The approach warning device of the present invention uses UWB technology. First, the UWB technology will be described. Basically, the UWB technology is a wireless system that occupies an ultra-wide frequency bandwidth and realizes ultra-high-speed communication over a short distance by transmitting information as an impulse signal. For example, as shown in FIG. 7 , data to be transmitted is transmitted as an impulse signal 3 such as a transmission wave from the transmission / reception antenna 2 of the UWB radio (transmission) 1. The impulse signal 3 is received by the transmitting / receiving antenna 5 of the UWB radio (reception) 4 and restored as data (communication function).

Further, since the UWB technology transmits an impulse signal, it can be used as a radar and can perform distance measurement at the same time. For example, as shown in FIG. 8 , a transmission wave based on the impulse signal 3 is transmitted from the transmission / reception antenna 2 of the UWB wireless device 1. The transmitted wave is reflected by the measurement object including the worker 6, and the reflected wave 7 is received by the transmission / reception antenna 2 of the UWB wireless device 1. When this transmission / reception time difference (transmission / reception timing difference) is Δt [s], the approach distance d [m] can be calculated by d = (Δt × 3 × 10 ⁸ ) / 2 (distance measurement). function).

  Further, unlike the normal wireless system, the UWB technology does not require a carrier signal, so that the wireless circuit can be simplified, and a small chip-type wireless device with low power consumption can be realized.

1 to 6 show an example of an embodiment of an approach warning device of the present invention. The approach warning device calculates the approach distance d of the worker 6 based on the transmission timing of the impulse signal 3 and the reception timing of the reflected wave 7 of the impulse signal 3, and stores the approach distance d and the memory 31 as a storage means in advance. The approach distance detecting means 8 for transmitting the approach limit distance dmax superimposed on the impulse signal 3 and the alarm means 9 for receiving the impulse signal 3 and operating when the approach distance d is shorter than the approach limit distance dmax. The approach distance detecting means 8 is installed at a position affected by the magnetic flux change of the charging unit 11 and is operated by an induced current by electromagnetic induction. The approach distance detection means 8 has the function of the UWB radio 1 described above, and the alarm means 9 has the function of the UWB radio 4 described above.

  The approach warning device is used, for example, when working around an electrical facility that may cause an electric shock, and prevents the worker 6 from touching the charging unit 11 by mistake. The approach distance detecting means 8 formed in a chip shape is directly attached to the charging unit 11 of the electrical equipment. In the present embodiment, a plurality of approach distance detection means 8 are attached to the charging unit 11. The approach distance detecting means 8 acquires a power source by electromagnetic induction from the charging unit 11, periodically transmits an impulse signal 3, and measures the approach distance d with the worker 6 by a distance measuring function. At the same time, the approach distance d obtained by the measurement and the preset approach limit distance dmax [m] are superimposed on the transmitted impulse signal 3 and transmitted. Further, since the approach distance detection means 8 acquires the power supply by electromagnetic induction, when the electricity is not flowing through the charging unit 11, that is, the charging unit 11 that is the voltage is not applied to the portion (non- In the case of the charging unit 12), the approach distance detecting means 8 does not operate and the impulse signal 3 is not transmitted.

In the present embodiment, the operator member 6 is mounted, for example, attached to a helmet helmet type alarm the alarm means 9.

  The alarm means 9 receives the impulse signal 3 transmitted by the approach distance detection means 8, and the approach distance d between the worker 6 and the charging unit 11 to which the approach distance detection means 8 is attached becomes smaller than the approach limit distance dmax. If this happens, the operator 6 is warned not to approach the charging unit 11 any more.

  FIG. 2 shows the approach distance detecting means 8. The approach distance detection means 8 is formed in a chip shape, and includes a UWB transmission / reception unit 13 and a power supply unit 14. The power supply unit 14 generates electromotive force by electromagnetic induction from the charging unit 11 and supplies power to the UWB transmission / reception unit 13.

  FIG. 3 shows a circuit configuration of the UWB transceiver unit 13. The control unit 20 controls the entire UWB transmission / reception unit 13, but periodically controls the delay time calculation unit 21 to transmit the start signal to the clock generation unit 22. The clock generation unit 22 generates a clock according to the start signal and transmits it to the code generation unit 23. The code generation unit 23 generates a code based on data and a clock transmitted from the memory 31 that is a storage unit, and transmits the code to the pulse generation unit 24.

  The pulse generator 24 modulates the impulse signal 3 with the code from the code generator 23 and transmits it from the transmission / reception antenna 26 via the antenna duplexer 25. At the same time, the impulse signal 3 used for modulation is transmitted to the correlation unit 27.

  Further, the UWB transmission / reception unit 13 receives the impulse signal 3 (reflected wave 7) reflected by the worker 6 by the transmission / reception antenna 26, and transmits this to the correlation unit 27 via the antenna duplexer 25. The correlation unit 27 detects the correlation between the impulse signal 3 transmitted from the pulse generation unit 24 and the reflected wave 7 and transmits the correlation value to the detection unit 28. The peak detector 29 detects the timing at which the reflected wave 7 is received from the correlation value, and transmits the reception timing signal to the delay time calculator 21.

  The delay time calculation unit 21 calculates a delay time Δt from the timing when the start signal is transmitted and the timing when the reflected wave 7 is received, and transmits the delay time Δt to the distance calculation unit 30. The distance calculation unit 30 calculates the approach distance d between the charging unit 11 and the worker 6 from the delay time Δt and transmits it to the memory 31. An approach limit distance dmax is set in advance in the memory 31, and the approach distance d and the approach limit distance dmax are transmitted from the memory 31 to the code generation unit 23 in accordance with the timing at which the impulse signal 3 is transmitted. Superimpose and transmit.

  The access limit distance dmax to the memory 31 is set by operating the input unit 15. The input unit 15 is a switch, for example. A plurality of values are stored in advance as candidate values for the approach limit distance dmax in the memory 31, and the approach limit distance dmax is selected from the candidate values by operating the switch of the input unit 15. The operator selects the approach limit distance dmax according to the voltage class of the charging unit 11 or the like.

  FIG. 4 shows a helmet-type alarm device (hereinafter referred to as a helmet-type alarm device 9A) worn by the worker 6 as the alarm means 9. The UWB reception / control unit 32 is formed in a chip shape, and receives the impulse signal 3 from the approach distance detection means 8 attached to the charging unit 11. The UWB reception / control unit 32 compares the approach distance d between the worker 6 and the charging unit 11 and the approach limit distance dmax from the data superimposed on the impulse signal 3. When the approach distance d becomes smaller than the approach limit distance dmax, the buzzer 33 is sounded or the LED 34 is turned on to warn the worker 6 from approaching the charging unit 11 any more. . The button-type battery 35 supplies power to the UWB reception / control unit 32, the buzzer 33, and the LED 34.

FIG. 5 shows a circuit configuration of the UWB reception / control unit 32 . A control unit 39 controls the entire UWB receiver and control unit 32. The clock generator 40 generates a clock and transmits it to the code generator 41. The code generation unit 41 generates a code based on the clock and transmits the code to the pulse generation unit 42. The pulse generator 42 modulates the impulse signal 3 with the code from the code generator 41 and transmits it to the correlator 45.

  The reception antenna 43 receives the impulse signal 3 transmitted from the approach distance detection means 8 and transmits it to the correlation unit 45 via the antenna duplexer 44. The correlation unit 45 detects the correlation between the impulse signal 3 transmitted from the pulse generation unit 42 and the received wave, and transmits the correlation value to the detection unit 46. In the detection unit 46, data is restored from the correlation value and transmitted to the approach state diagnosis unit 47.

The approach state diagnosis unit 47 compares the approach distance d between the worker 6 and the charging unit 11 and the approach limit distance dmax from the data. When it is determined that the approach distance d is smaller than the approach limit distance dmax, it operates the buzzer 33 and LED 34, to alert so as not approach the charging unit 11 further against work skill 6.

FIG. 6 shows an alarm generation processing procedure of the approach alarm device of the present invention. The approach distance detection means 8 enters from the start step of the routine RT11, moves to step SP11, and sets the approach limit distance dmax in the memory 31 in advance.

  In the next step SP12, the impulse signal 3 (UWB signal) is transmitted and the reception of the reflected wave 7 is awaited. In step SP13, it is determined whether or not the reflected wave 7 has been received. If it is determined that the reflected wave 7 has not been received, the process returns to step SP12. On the other hand, if it is determined that it has been received, the process proceeds to SP14.

  In step SP14, the approach distance d is calculated based on the time difference Δt between the transmission timing and the reception timing of the impulse signal 3. In step SP15, the data of the approach distance d and the approach limit distance dmax are superimposed on the impulse signal 3 of step SP12 and transmitted.

Helmet type alarm 9 A, the process proceeds to step SP21 enters the start step of routine RT21. In step SP21, the impulse signal 3 from step 12 is received. In step SP22, it is determined whether or not the approach distance d between the worker 6 and the charging unit 11, which is the received data, is smaller than the approach limit distance dmax.

  If it is determined in step SP22 that the approach distance d is not smaller than the approach limit distance dmax (NO), the process returns to step SP21. On the other hand, if it is determined in step SP22 that the approach distance d is smaller than the approach limit distance dmax (YES), the process proceeds to SP23.

In step SP23, or to the buzzer 33, and alarm to the operator 6 by or to light the LED 3 4, it returns to step SP21.

  Since the approach distance detection means 8 measures the approach distance d of the worker 6 by utilizing the reflection of the impulse signal 3 which is a UWB signal hitting the worker 6, the charging unit 11 of the worker 6 is the most charged part 11 as the approach distance d. It is possible to measure the distance between the part close to the charging unit 11 and the charging unit 11. For example, when the worker 6 reaches for the charging unit 11, the distance between the fingertip and the charging unit 11 can be measured. For this reason, for example, the approach distance d can be accurately measured even when the operator 6 extends his / her hand without moving the place.

  Further, the distance measurement by transmission / reception of the impulse signal 3 is in principle highly accurate. Then, the distance can be measured without being affected by the change in electric field intensity caused by the shape and position of the charging unit 11 as in the case of a voltage detector. For these reasons, the approach distance of the worker 6 can be measured with high accuracy and stability, and the reliability of the alarm can be improved.

  Further, since the approaching distance detecting means 8 is directly attached to the charging unit 11, the approaching distance to the approaching distance detecting means 8 of the worker 6 matches the approaching distance to the charging part 11, and the approaching to the charging part 11. It becomes easy to measure the distance (separation distance from the charging unit) more accurately.

  Moreover, since the UWB reception / control part 32 of the alarm means 9 can be formed in a chip shape, the alarm means 9 can be reduced in size and weight. For this reason, it is easy to make the alarm means 9 into the helmet type alarm device 9A, and the alarm means 9 that is convenient to carry can be provided. And since the warning means 9 can be reduced in size and weight, the warning means 9 is hard to get in the way of work, and the deterioration of work efficiency can be prevented.

  Moreover, since the approach distance detection means 8 can be formed in a chip shape, it does not take a place for installation. For this reason, it can install in various places and the freedom degree of selection of an installation place improves.

  Furthermore, by changing the value of the approach limit distance dmax stored in the memory 31 in advance, the approach distance d of the worker 6 on which the alarm means 9 is activated can be changed. For this reason, by changing the approach limit distance dmax according to the voltage class of the charging unit 11 and the like, it is possible to cope with electrical equipment of various voltage classes, and to improve the versatility of the proximity alarm device.

  Further, since the approach distance detecting means 8 is operated by an induced current by electromagnetic induction with the charging unit 11, a special power source can be dispensed with. Further, there is no need to worry about running out of the battery as in the case of using a battery as a power source, and it is easy to use. Furthermore, it is necessary to operate the approach distance detection means 8 when the current flows through the charging unit 11 (when the position where the approach distance detection means 8 is installed is the charging part 11). In some cases, the approach distance detecting means 8 can be operated. On the other hand, when it is not necessary to operate the approach distance detecting means 8 (when the position where the approach distance detecting means 8 is installed is the non-charging unit 12), the approach distance detecting means 8 does not operate. Therefore, generation of an extra impulse signal 3 can be prevented.

  Moreover, you may control the range which can receive the impulse signal 3 by adjusting the output which the approach distance detection means 8 transmits the impulse signal 3. FIG. That is, in the range where the impulse signal 3 can be received, the alarm means 9 of all workers 6 will issue an alarm, but an operator who needs to issue an alarm by adjusting the transmission output of the impulse signal 3 The number of 6 can be limited.

The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the above description, the approach distance d measured by the approach distance detecting means 8 on the transmission side and the preset approach limit distance dmax are transmitted, and the approach of the worker 6 is judged by the alert means 9 on the receiving side to alert However, it is not necessarily limited to this configuration. For example, it is conceivable that an alarm signal is transmitted after the approach distance detecting means 8 on the transmission side determines the approach of the worker 6, and the alarm means 9 on the receiving side issues an alarm upon reception of the alarm signal. That is, the approach distance d of the worker 6 is calculated based on the transmission timing of the impulse signal 3 and the reception timing of the reflected wave 7 of the impulse signal 3, and is stored in advance in the memory 31 which is the approach distance d and storage means. When the approach distance dmax is shorter than the approach limit distance dmax by comparing the approach limit distance dmax, the approach distance detecting means 8 that superimposes the alarm signal on the impulse signal 3 and transmits the impulse signal 3, and the impulse signal 3 is received. The approaching distance detecting means 8 is installed at a position affected by the magnetic flux change of the charging unit 11 and may be an approaching alarm device that operates with an induced current by electromagnetic induction. In this case, it is possible to achieve the same effect as proximity warning apparatus of FIGS 6.

Further, the preset approach limit distance dmax may be stored in the alarm means 9 on the receiver side. That is, the approach distance d measured by the approach distance detection means 8 on the transmission side is transmitted, and the approach distance d received by the alarm means 9 on the receiver side is compared with the preset approach limit distance dmax. It is also conceivable to judge the approach of 6 and warn. That is, the approach distance detection of the worker 6 is calculated based on the transmission timing of the impulse signal 3 and the reception timing of the reflected wave 7 of the impulse signal 3, and the approach distance d is superimposed on the impulse signal 3 and transmitted. The alarm means 9 is activated when the means 8 receives the impulse signal 3 and compares the approach distance d with the approach limit distance dmax stored in advance in the storage means and the approach distance d is shorter than the approach limit distance dmax. The approach distance detecting means 8 may be installed at a position that is affected by the magnetic flux change of the charging unit 11 and may be an approach alarm device that operates with an induced current by electromagnetic induction. In this case, it is possible to achieve the same effect as proximity warning apparatus of FIGS 6.

  In the above description, the alarm means 9 worn by the worker 6 is the helmet type alarm device 9A, but is not limited to the helmet type alarm device 9A. For example, an alarm device 9A attached to the body by attaching it to a wristband or a waist belt may be used, or an alarm device 9A attached to the body by forming a storage pocket in the work clothes and storing the pocket therein. Alternatively, an alarm device 9A or the like attached to the body by being attached to a work shoe or the like may be used.

  In the above description, the approach distance detection unit 8 is directly attached to the charging unit 11. However, the approaching distance detecting unit 8 may be attached indirectly or may be installed around the charging unit 11. That is, the approach distance detection means 8 is installed at a position that is affected by the magnetic flux change of the charging unit 11, and may not be directly attached to the charging unit 11 as long as a power source can be secured by electromagnetic induction.

  In the above description, a plurality of approach distance detecting means 8 are provided, but the number of approach distance detecting means 8 may be one depending on the work site.

Further, in the above description, the alarm means 9 has issued an alarm to the worker by operating the buzzer 33 and the LED 34, but is not limited to this, and stimulates one of the human senses such as a vibrator. Means may be used.

  In the above description, the input unit 15 is a switch, and one approach limit distance dmax is selected from a plurality of candidate values stored in advance in the memory 31 by the switch operation. It is not limited to. For example, the input unit 15 may be a keyboard, and the value of the approach limit distance dmax may be directly input to the memory 31.

It is a schematic block diagram which shows the approach warning apparatus of this invention. It is a figure which shows the structure of an approach distance detection means. It is a block diagram which shows the circuit structure of a UWB transmission / reception part. It is a figure which shows a helmet type alarm device. It is a block diagram which shows the circuit structure of a UWB receiving part. It is a flowchart which shows an alarm generation process procedure. It is a figure for demonstrating the communication function by the impulse signal of UWB technique. It is a figure for demonstrating the ranging function by the impulse signal of UWB technique. It is a top view of the conventional safety helmet. It is a side view of the conventional safety helmet. It is a block diagram which shows the circuit structure of the non-contact type voltage detector of the conventional safety helmet.

Explanation of symbols

3 impulse signal 6 worker 7 impulse signal of the reflected wave 8 approach distance detecting means 9 alarm hands stage
1 1 Charging unit 31 Memory (storage means)

Claims (4)

The approach distance of the operator is calculated based on the transmission timing of the impulse signal and the reception timing of the reflected wave of the impulse signal, and the approach distance and the approach limit distance stored in advance in the storage means are superimposed on the impulse signal. And an approach distance detecting means for transmitting and an alarm means which is attached to a member worn by an operator, receives the impulse signal, and operates when the approach distance is shorter than the approach limit distance. A proximity alarm device characterized in that the distance detecting means is installed at a position affected by a change in magnetic flux of the charging unit and is operated by an induced current by electromagnetic induction. The approach distance of the worker is calculated based on the transmission timing of the impulse signal and the reception timing of the reflected wave of the impulse signal, and the approach distance is compared with the approach limit distance stored in advance in the storage means. When the distance is shorter than the approach limit distance, an approach distance detecting means for superimposing and transmitting an alarm signal on the impulse signal, and attached to a member worn by an operator, receiving the impulse signal, An approach alarm device, wherein the approach distance detector is installed at a position affected by a change in magnetic flux of the charging unit and is activated by an induced current caused by electromagnetic induction. It calculates the approach distance of the operator based on the reception timing of the reflected wave of the impulse signal and the transmission timing of the impulse signal, and the approach distance detection means for transmitting the approach distance to be superimposed on the impulse signal, worker An alarm that is attached to a member to be mounted , receives the impulse signal, and operates when the approach distance is shorter than the approach limit distance by comparing the approach distance with the approach limit distance stored in advance in the storage means A proximity alarm device, wherein the approach distance detecting means is installed at a position affected by a change in magnetic flux of the charging unit and is operated by an induced current by electromagnetic induction. The approach warning device according to any one of claims 1 to 3, wherein the approach distance detecting means is directly attached to the charging unit .

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