JP6074079B1 - Maintenance work safety device - Google Patents

Abstract

An object of the present invention is to detect with a simple configuration whether maintenance inspection work in a hoistway is correctly performed. SOLUTION: Worker detection means for detecting a position of a worker who performs maintenance and inspection of an elevator in a hoistway, and work information including posture and movement during the work of the worker are detected to generate operation information. Operation detection means, car detection means for detecting elevator car position, correct work posture of the worker corresponding to the work position in the hoistway, and normal work information storage means for storing correct work operation as normal work information The worker is searched for the regular work information storage means based on the worker position data from the worker detection means, the worker motion information from the motion detection means, and the elevator car position data from the car detection means. Determining means for determining whether or not the work according to the regular work information is being performed, and notification means for notifying that if the worker's work does not conform to the regular work as a result of the determination Equipped with a. [Selection] Figure 1

Description

  Embodiments described herein relate generally to a maintenance work safety device.

  Elevator maintenance / inspection involves work in a narrow space of a hoistway or work on a car. Therefore, ensuring the safety of workers is a top priority during maintenance and inspection. The maintenance and inspection work is made into a manual, and the correct work is set according to the inspection location.

  Conventionally, various types of safety protectors have been proposed. Also known is a system for detecting that an operator has forgotten to wear a safety protective device.

Japanese Patent Laid-Open No. 2003-067877

  However, although the maintenance and inspection work itself is made into a manual, under the maintenance and inspection work in a narrow hoistway, it is necessary to judge whether the operator is actually performing the correct maintenance or inspection work. Is not easy.

  An object of the present invention is to provide a maintenance work safety device that can detect with a simple configuration whether maintenance inspection work in a hoistway is correctly performed.

  An embodiment for achieving the above object includes worker detection means for detecting the position of a worker who performs maintenance and inspection of an elevator in a hoistway, and work operation including posture and movement of the worker during work. The operation detection means for detecting and outputting as operation information, the car detection means for detecting the car position of the elevator, the correct work posture of the worker corresponding to the work position in the hoistway, and the correct work movement are regular work. Regular work information storage means for storing as information, position data of the worker from the worker detection means, operation information of the worker from the motion detection means, and car position data of the elevator from the car detection means And a determination result for determining whether or not the worker is performing a work conforming to the regular work information, and a result of the determination If the work of the worker is not in accordance with normal operation, and a notifying means for notifying to that effect.

The block diagram which shows the maintenance work safety device which concerns on 1st Embodiment. The flowchart explaining the effect | action of 1st Embodiment. The block diagram which shows the maintenance work safety device which concerns on 2nd Embodiment. The flowchart explaining the effect | action of 2nd Embodiment. The block diagram which shows the maintenance work safety apparatus which concerns on 3rd Embodiment. The flowchart explaining the effect | action of 3rd Embodiment. The block diagram which shows the maintenance work safety device which concerns on 4th Embodiment. The flowchart explaining the effect | action of 4th Embodiment. The block diagram which shows the maintenance work safety apparatus which concerns on 5th Embodiment. The flowchart explaining the effect | action of 5th Embodiment. The block diagram which shows the maintenance work safety device which concerns on 6th Embodiment. The flowchart explaining the effect | action of 6th Embodiment.

<First Embodiment>
FIG. 1 is a configuration diagram showing the first embodiment.

  A maintenance work safety device 1A according to the first embodiment shown in the figure is a device that detects whether a worker 5 who performs maintenance / inspection of an elevator 2 including a car 3 and a control panel 4 is performing a correct work. is there. The maintenance work safety device 1A of the first embodiment includes a car detection unit 6, an operator detection unit 7, an operation detection unit 8, a regular work information storage unit 9, a determination unit 10, and a notification control unit 11. And a notification unit 12.

  The car detection unit 6 receives car position information from the control panel 4 to detect the current position of the car 3 being driven, and outputs the current position to the determination unit 10 as car position data.

  The worker detection unit 7 is a position sensor that detects a position where the worker 5 is working in an elevator hoistway or on a car. Specifically, an infrared human sensor or the like is arranged, and position data is output to the determination unit 10 when the worker 5 is located within the detection range. The worker detection unit 7 can also use a position sensor such as a camera or GPS.

  The motion detection unit 8 detects the motion of the worker 5 who is working, and can be configured by a sensor camera, for example. The captured camera image is output to the determination unit 10 as operation information.

  The regular work information storage unit 9 is a detailed manual of the work performed by the worker 5. Specifically, the image of the regular work corresponding to the car position, the work item, and the safety protection necessary for the work are stored as a pair. For example, if you are working on a car, whether the worker is in the correct position on the car, is wearing the correct safety protection, is using the correct tool, is using the tool correctly, is in the correct work posture ( Various reference information as a regular work is stored, such as whether or not the posture is taken.

  The determination unit 10 performs work including the car position data from the car detection unit 6, the position data of the worker 5 from the worker detection unit 7, and the posture and movement of the worker 5 output from the operation detection unit 8 during the work. The regular work information storage unit 9 is searched based on the motion information indicating the motion to determine whether the worker 5 is performing regular work.

  When the determination unit 10 determines that the worker 5 is not performing regular work, the notification control unit 11 controls the notification unit 12 so that a warning is generated by voice according to the content. For example, when the work is not performed in the correct posture, a warning message “Please work in the correct posture” is notified from the notification unit 12. The notification unit 12 includes a speaker or the like, and has a function of providing voice guidance to the worker 5. Note that the notification unit 12 is not limited to a speaker, and may be a buzzer sound or an alarm sound, or may warn by light such as blinking of a lamp, character display, or the like.

  Next, the operation of the first embodiment will be described based on the flowchart of FIG.

  Prior to the start of maintenance / inspection work for the elevator 2, first, the position of the car 3 in the hoistway of the elevator 2 is detected by the car detection unit 6 (step S1). The work position of the worker 5 is detected by the worker detection unit 7 (step S2). Further, the work posture / motion of the worker 5 is detected by the motion detection unit 8 (step S3).

  Next, based on the detected car position data of the car 3, the position data of the worker 5, and the operation information of the worker 5, it is determined whether or not the worker 5 is currently performing a maintenance check (step). S4). If it is determined that work is in progress, the database in the regular work information storage unit 9 is searched to obtain regular work information (step S5). Based on the acquired regular work information, the determination unit 10 determines whether the maintenance / inspection work of the worker 5 conforms to the regular work (step S6). As a result of the determination, when it is determined that the maintenance / inspection work of the worker 5 is not in accordance with the regular work, an instruction for notifying the warning is issued to the notification control unit 11, and the notification unit 12 provides the worker with the warning. 5 is notified of the warning (step S7).

  As described above, in the first embodiment, when the maintenance / inspection work of the worker 5 does not conform to the regular work, the worker 5 is notified of the warning. Regular work can be taught, and safety of maintenance and inspection work can be improved.

<Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to FIGS. In addition, the same number is attached | subjected to the same component as 1st Embodiment, and the description is abbreviate | omitted.

  The second embodiment is characterized by having a function of invalidating the current operation command of the elevator 2 based on the determination result of the determination unit. As shown in FIG. 3, the maintenance work safety device 1B of the second embodiment is similar to the first embodiment in that the car detection unit 6, the worker detection unit 7, the operation detection unit 8, the regular work information storage unit 9, In addition to the determination unit 10, the notification control unit 11, and the notification unit 12, a command acquisition unit 13 and a command invalidation unit 14 are newly provided.

  The command acquisition unit 13 acquires from the control panel 4 an “operation command” indicating what command the current operation of the elevator 2 is operating.

  The command invalidation unit 14 invalidates the current “driving command” when the determination unit 10 determines that the worker 5 is not performing regular work. For example, when the work position of the worker 5 is on the car and the operation command is “high-speed operation”, the operation command is invalidated.

  Next, the operation of the second embodiment will be described based on the flowchart of FIG.

  In FIG. 4, the processes of steps S21 to S27 are the same as the processes of steps S1 to S7 shown in FIG. The command acquisition unit 13 acquires the current operation command of the elevator 2 from the control panel 4. If the current operation command does not conform to the regular work that is currently being performed, the command invalidation unit 14 outputs a command to invalidate the current operation command to the control panel 4 (step S28). For example, when a driving command is output during work on the elevator 2 or during work in the pit, this is invalidated and the car is stopped. In addition, you may make it invalidate a driving command before step S27 notified to the operator 5. FIG.

  As described above, in the second embodiment, the operation command is invalidated when it is determined that the worker 5 is not performing work according to regular work. For this reason, it is possible to further ensure the safety of the worker 5 engaged in the maintenance inspection work.

<Third Embodiment>
Next, a third embodiment of the present invention will be described with reference to FIGS. In addition, the same number is attached | subjected to the same component as 2nd Embodiment, and the description is abbreviate | omitted.

  The third embodiment is characterized by having a function of changing the current operation mode of the elevator 2 based on the determination result of the determination unit 10.

  As shown in FIG. 5, the maintenance work safety device 1 </ b> C of the third embodiment is similar to the second embodiment in that the car detection unit 6, the worker detection unit 7, the operation detection unit 8, and the regular work information storage unit 9. And a determination unit 10, a notification control unit 11, a notification unit 12, a command acquisition unit 13, and a command invalidation unit 14, and a new operation mode acquisition unit 15 and a driving mode change unit 16.

  The operation mode acquisition unit 15 acquires from the control panel 4 an “operation mode” indicating in what mode the current operation mode of the elevator 2 is operating.

  When the determination unit 10 determines that the worker 5 is not performing regular work, the operation mode change unit 16 changes the current “operation mode” to another operation mode. For example, when the work position of the worker 5 is on the car and the operation command is “normal operation mode”, the operation mode is changed to “maintenance inspection mode”.

  Next, the operation of the third embodiment will be described based on the flowchart of FIG.

  In FIG. 6, the processes of steps S31 to S38 are the same as the processes of steps S21 to S28 shown in FIG. The operation mode acquisition unit 15 acquires the current operation mode of the elevator 2 from the control panel 4. When the current operation mode does not conform to the regular work that is currently being performed, the operation mode change unit 16 outputs a command for changing the current operation mode to the control panel 4. For example, if the current operation mode is the normal operation mode during work on the elevator 2 or in the pit, the operator 5 is informed (step S37), and then the operation instruction is temporarily invalidated. (Step S38) and change to the maintenance inspection mode (step S39). The operation mode may be changed before step S37 for notifying the worker or step S38 for invalidating the operation command.

  As described above, in the third embodiment, the operation mode is changed when it is determined that the worker 5 is not performing work according to regular work. For this reason, the safety | security of maintenance inspection work can be improved further.

<Fourth Embodiment>
Next, a fourth embodiment of the present invention will be described with reference to FIGS. In addition, the same number is attached | subjected to the same component as 1st-3rd embodiment, and the description is abbreviate | omitted.

  In the fourth embodiment, the time change of the operation of the worker 5 is detected, and when there is no time change in the operation of the worker 5 within a predetermined time, the notification is made to the outside. As shown in FIG. 7, the maintenance work safety device 1D of the fourth embodiment is similar to the third embodiment in that the car detection unit 6, the worker detection unit 7, the operation detection unit 8, and the regular work information storage unit 9 are used. A determination unit 10, a notification control unit 11, a notification unit 12, a command acquisition unit 13, a command invalidation unit 14, an operation mode acquisition unit 15 and an operation mode change unit 16, and a new operation change detection unit 17, The acquisition time storage unit 18, the elapsed time measurement unit 19, the change determination unit 20, the external notification control unit 21, and the external notification unit 22 are provided.

  The motion change detection unit 17 inputs the motion information of the worker 5 from the motion detection unit 8 every predetermined time, and detects the motion vector, for example. Note that in a simple configuration, still images may be captured every predetermined period, and the captured still images may be compared to detect whether there is a change in motion after a certain period of time.

  The acquisition time storage unit 18 stores the time when the operation information from the operation detection unit 8 is acquired.

  The elapsed time measurement unit 19 measures the elapsed time from the time when the operation information is acquired from the operation detection unit 8.

  The change determination unit 20 moves based on the motion of the worker based on the motion vector from the motion change detection unit 17, the acquisition start time stored in the acquisition time storage unit 18, and the elapsed time measured by the elapsed time measurement unit 19. It is determined whether or not there is.

  The external notification control unit 21 controls the external notification unit 22 based on the determination result of the change determination unit 20 to notify the operator that an abnormality has occurred.

  The external notification unit 22 includes a wireless facility, and notifies the disaster prevention center that manages the building, the control room of the elevator management center, and the like that an abnormality has occurred to the worker 5 during the maintenance check.

  Next, the operation of the fourth embodiment will be described based on the flowchart of FIG.

  In FIG. 8, in the processing of steps S41 to S43, the position of the elevator car 2 in the hoistway of the elevator 2 is detected by the car detector 6 as in the above-described embodiments, and the work position of the worker 5 is determined by the worker. It is detected by the detection unit 7. Further, the operation detection unit 8 detects the work posture / operation of the worker 5. At that time, the motion change detection unit 17 detects the motion vector by inputting the motion information of the worker 5 from the motion detection unit 8 every predetermined time. The acquisition time storage unit 18 stores the time when the operation information from the operation detection unit 8 is acquired. Further, the elapsed time measuring unit 19 measures the elapsed time from the time when the operation information is acquired from the operation detecting unit 8.

  Based on the motion vector from the motion change detection unit 17, the acquisition start time stored in the acquisition time storage unit 18, and the elapsed time measured by the elapsed time measurement unit 19, the change determination unit 20 It is determined whether or not there is a movement in the operation 5 (step S44). If no change is detected in the operation of the worker 5 over a predetermined time, it is considered that some abnormality has occurred in the worker 5, and the fact is notified to the outside (step S45). Thereby, the safety of the worker 5 can be ensured.

  In the determination process in step S44, a change in the operation of the worker 5 can be detected, and if the work of the worker 5 is a maintenance inspection work, the determination unit 10 acquires the regular work information from the regular work information storage unit 9. (Step S47), it is determined whether or not the current maintenance inspection work conforms to the regular work (Step S48). Thereafter, if not conforming to the regular work, the worker 5 is notified, or the driving command is invalidated or the driving mode is changed (steps S49, S50, S51).

  As described above, in the fourth embodiment, the same effects as those of the above-described embodiments can be obtained, and the abnormality of the operator 5 can be quickly found, and safe and efficient maintenance and inspection work can be performed.

  In this embodiment, by detecting a motion vector, it is possible to detect a special motion that cannot be assumed in normal operation. For this reason, it is also possible to detect whether or not the work is a regular work by detecting not only a point where the movement of the worker 5 is not changed but also an abnormal movement.

<Fifth Embodiment>
Next, a fifth embodiment of the present invention will be described with reference to FIGS. In addition, the same number is attached | subjected to the same component as each 1st-4th embodiment, and the description is abbreviate | omitted.

  The fifth embodiment is characterized in that the determination function of the determination unit 10 is invalidated. As shown in FIG. 9, the maintenance work safety apparatus 1E of the fifth embodiment is similar to the fourth embodiment in that the car detection unit 6, the worker detection unit 7, the operation detection unit 8, and the regular work information storage unit 9 are used. , Determination unit 10, notification control unit 11, notification unit 12, command acquisition unit 13, command invalidation unit 14, operation mode acquisition unit 15, operation mode change unit 16, operation change detection unit 17, acquisition time storage unit 18, and progress A time measurement unit 19, a change determination unit 20, an external notification control unit 21, and an external notification unit 22 are provided, and a determination function invalidation unit 23 is newly provided.

  The determination function invalidation unit 23 invalidates the determination function of the determination unit 10 in maintenance and inspection work in an emergency. In other words, in an emergency response such as when an earthquake occurs, there is a case where the work does not conform to the regular work. In such a case, the determination function invalidation unit 23 instructs the determination unit 10 to invalidate the determination function itself. In this case, the determination function invalidation unit 23 may be configured to output a predetermined determination function invalidation command to the determination unit 10 from a terminal held by the worker 5. Or the structure which provides a dedicated switch in the maintenance box in a cage | basket | car may be sufficient. Further, it may be invalidated by a predetermined operation of the destination floor button by the operator 5. In addition, it is not appropriate to give the invalid authority of the determination function to all the workers 5. For this reason, it is desirable to configure so that only a site manager who has a legitimate authority can operate the determination function invalidating unit 23.

  Next, the operation of the fifth embodiment will be described based on the flowchart of FIG.

  In FIG. 10, the processing of steps S61 to S66 is the same as the processing of steps S41 to S46 shown in FIG. In the fifth embodiment, in addition to the operation of the fourth embodiment, a process for determining whether or not the determination function of the determination unit 10 is valid is added (step S67). When the operator 5 operates the determination function invalidation unit 23 to invalidate the determination function of the determination unit 10 (NO in step S67), the subsequent determination process ends. If not invalidated (YES in step S67), as in the fourth embodiment, the determination unit 10 acquires regular work information from the regular work information storage unit 9 (step S68), and the current maintenance / inspection work is authorized. It is determined whether or not it conforms to the work (step S69). Thereafter, if not conforming to the regular work, the worker 5 is notified, or the driving command is invalidated or the driving mode is changed (steps S70 to S72).

  As described above, in the fifth embodiment, the same effects as those of the above embodiments can be obtained, and the determination function can be invalidated as necessary, so that efficient maintenance and inspection work can be performed.

<Sixth Embodiment>
Next, a sixth embodiment of the present invention will be described with reference to FIGS. In addition, the same number is attached | subjected to the same component as each 1st-5th embodiment, and the description is abbreviate | omitted.

  The sixth embodiment is characterized in that the change determination function by the change determination unit 20 is invalidated. As shown in FIG. 11, the maintenance work safety device 1F of the sixth embodiment is similar to the fifth embodiment in that the car detection unit 6, the worker detection unit 7, the operation detection unit 8, and the regular work information storage unit 9 are used. , Determination unit 10, notification control unit 11, notification unit 12, command acquisition unit 13, command invalidation unit 14, operation mode acquisition unit 15, operation mode change unit 16, operation change detection unit 17, acquisition time storage unit 18, and progress A time measurement unit 19, a change determination unit 20, an external notification control unit 21, an external notification unit 22, and a determination function invalidation unit 23 are provided, and a change determination function invalidation unit 24 is newly provided.

  The change determination function invalidation unit 24 invalidates the change determination function itself by the change determination unit 20. Depending on the work contents of the worker 5, work with little change in movement may be considered. In such a case, there is a problem that even if the operator 5 has no abnormality, the abnormality is notified to the outside as “abnormality occurrence”. The change determination function invalidation unit 24 may be configured to output a predetermined change determination function invalidation command to the change determination unit 20 from a terminal held by the worker 5. Or the structure which provides a dedicated switch in the maintenance box in a cage | basket | car may be sufficient. Further, it may be invalidated by a predetermined operation of the destination floor button by the operator 5. Moreover, it is not appropriate to give the invalid authority of the change determination function to all the workers 5. For this reason, it is desirable to configure so that only a site manager who has a legitimate authority can operate the change determination function invalidating unit 24.

  Next, the operation of the sixth embodiment will be described based on the flowchart of FIG.

  In FIG. 12, the processes of steps S81 to S83 are the same as the processes of steps S61 to S86 shown in FIG. In the sixth embodiment, in addition to the operation of the fifth embodiment, a process for determining whether or not the change determination function of the change determination unit 20 is valid is added (step S84). When the operator 5 operates the change determination function invalidation unit 24 to invalidate the determination function of the change determination unit 20 (NO in step S84), the subsequent determination process ends. If not invalidated (YES in step S84), the change determination unit 20 is measured by the motion vector from the motion change detection unit 17, the acquisition start time stored in the acquisition time storage unit 18, and the elapsed time measurement unit 19. Based on the elapsed time, it is determined whether or not there is a movement in the operation of the worker 5 within a predetermined time (step S85). If no change is detected in the operation of the worker 5 over a predetermined time, it is considered that some abnormality has occurred in the worker 5, and the fact is notified to the outside (step S86). Thereby, the safety of the worker 5 can be ensured. If the change in the operation of the worker 5 can be detected and the work of the worker 5 is a maintenance inspection work, the determination unit 10 acquires the regular work information from the regular work information storage unit 9 as in the fifth embodiment. (Step S89), it is determined whether or not the current maintenance inspection work conforms to the regular work (Step S90). Thereafter, if not conforming to the regular work, the worker 5 is notified, or the driving command is invalidated or the driving mode is changed (steps S91 to S93).

  As described above, in the sixth embodiment, the same effects as those of the above-described embodiments can be obtained, and notification to the outside can be limited depending on the situation, so that unnecessary external notification can be prevented and efficiency can be prevented. Maintenance and inspection work can be performed.

  In each of the above embodiments, a determination function invalidation unit may be provided, and the determination function of the determination unit 10 may be invalidated in maintenance and inspection work in an emergency. In this case, the determination function invalidation unit may be configured to output a predetermined determination function release command from the terminal held by the worker 5 to the determination unit 10. Or the structure which provides a dedicated switch in the maintenance box in a cage | basket | car may be sufficient. Further, it may be invalidated by a predetermined operation of the destination floor button by the operator 5. On the other hand, the operator 5 that can be invalidated may be limited so that only the person in charge of the field can invalidate it.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  1A, 1B, 1C, 1D, 1E, 1F ... Maintenance work safety device, 2 ... Elevator, 3 ... Car, 4 ... Control panel, 5 ... Worker, 6 ... Car detector, 7 ... Worker detector, 8 ... Operation detection unit, 9 ... Regular work information storage unit, 10 ... Determination unit, 11 ... Notification control unit, 12 ... Notification unit, 13 ... Command acquisition unit, 14 ... Command invalidation unit, 15 ... Operation mode acquisition unit, 16 ... Operation mode change unit, 17 ... operation change detection unit, 18 ... acquisition time storage unit, 19 ... elapsed time measurement unit, 20 ... change determination unit, 21 ... external notification control unit, 22 ... external notification unit, 23 ... determination function invalid Conversion unit, 24 ... change determination function invalidation unit

Claims (9)

Worker detection means for detecting the position of the worker performing the maintenance inspection of the elevator in the hoistway;
Motion detection means for detecting work motion including posture and motion during work of the worker and outputting as motion information;
Car detection means for detecting a car position of the elevator;
Regular work information storage means for storing the correct work posture of the worker corresponding to the work position in the hoistway and the correct work operation as regular work information;
The regular work information storage means is searched based on the worker position data from the worker detection means, the worker action information from the action detection means, and the elevator car position data from the car detection means. Determining means for determining whether the worker is performing work according to the regular work information;
As a result of the determination, when the worker's work does not conform to the regular work, a maintenance work safety device is provided that includes a notifying means for notifying that effect. Driving instruction acquisition means for acquiring an operating instruction of the elevator,
A driving command invalidating unit that invalidates the driving command acquired by the driving command acquiring unit;
The result of determination by the determination means is that the operation command invalidating means invalidates the operation command and stops the operation of the elevator when the work of the worker does not conform to regular work. The maintenance work safety device according to Item 1. An operation mode acquisition means for acquiring an operation mode of the elevator;
And further comprising an operation mode change means for changing the operation mode acquired by the operation mode acquisition means,
The maintenance according to claim 1 or 2, wherein, as a result of the determination by the determination means, if the worker's work does not conform to a regular work, the operation mode change means changes the current operation mode. Work safety device. Motion change detection means for detecting a time change of the motion information acquired from the motion detection means;
An acquisition time storage means for storing the time when the operation information is detected;
Elapsed time measuring means for measuring the elapsed time from the time when the operation information was detected,
Based on the detection result of the operation change detection means, the detection time of the acquisition time storage means, and the measurement result of the elapsed time measurement means, whether or not there is a certain change in the operator's action within a predetermined time Change determination means for determining whether or not
The apparatus further comprises external notification means for notifying the outside that the worker is in an abnormal state when the change determining means determines that the worker has not operated for a certain time or more. The maintenance work safety device according to any one of claims 1 to 3. A determination function invalidating means for invalidating the determination function of the determination means;
The maintenance work safety device according to any one of claims 1 to 4, wherein the determination function invalidation unit invalidates the determination function of the determination unit by performing a predetermined operation.   6. The maintenance work safety device according to claim 5, wherein the determination function invalidation means cannot be invalidated by the worker, and invalidation authority is set for a specific person.   6. The maintenance work safety device according to claim 5, wherein the determination function invalidation means is set to be invalidated by a predetermined operation by the worker.   5. The maintenance work safety device according to claim 4, further comprising a change determination function invalidating means for invalidating a change determination function of the change determination means by performing a predetermined operation.   9. The maintenance work safety device according to claim 8, wherein the change determination function invalidation means disables invalidation by a predetermined operation by the worker.

Images