JP2013052948A - Safety device for vehicle for high lift work - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safety device for a vehicle for high lift work, preventing an accident where an operator is caught between a work platform and a structure without lowering work efficiency.SOLUTION: The safety device includes: a distance measurement sensor 60 detecting a separation distance to an object above a work platform; an alarm device 56 performing alarm actuation at a first distance threshold or less; a regulation determination part 73 regulating the actuation in a direction approaching the object at a second distance threshold smaller than the first distance threshold; and a regulation release switch 54 releasing the actuation regulation by the regulation determination part 73. When the regulation release switch 54 is operated in a state where the actuation of a boom is regulated by the regulation determination part 73, the actuation of the boom in a direction for separating the work platform away from the object in response to an operation signal from an operation device 50 is allowed, and the alarm actuation of the alarm device 56 is continued until the separation distance exceeds the first distance threshold.

Description

The present invention relates to a safety device for an aerial work vehicle provided with a lifting device that lifts and lowers a work board for worker boarding to a desired height.

The aerial work platform includes a lifting device (e.g., a boom device) disposed on a movable vehicle body so as to be movable up and down, and a work board for worker boarding provided at a tip portion of the lifting device, It is a vehicle that is configured to move the work platform to an arbitrary high position by operating a lifting device by operating an operation device provided on the work table by an operator boarded on the work table. It is used for work at various heights such as building and ship construction, highway construction, etc. (see, for example, Patent Document 1).

JP 2009-208913 A

By the way, when working at a high place in a work site such as indoors or in a road tunnel,
There is a limit to the work height at which work can be performed safely in relation to structures such as ceilings and beams installed above. Under such circumstances, when an operation is performed to move the workbench upward, if the operator does not notice the presence of the upper structure or accidentally brings the workbench too close to the upper structure, There is a risk that an operator may be caught between the work table and the upper structure. On the other hand, in order to avoid such a situation, it is necessary for the worker to pay careful attention to the operation of moving the work table upward and to make safety the highest priority, but always be aware of the upper structure. There is a problem that attention is distracted with respect to the original work and work efficiency is lowered.

The present invention has been made in view of such a problem, and prevents an accident in which an operator is caught between a workbench and a structure without incurring a reduction in work efficiency, thereby improving safety. An object of the present invention is to provide a safety device for an aerial work vehicle that can be secured.

In order to solve the above problems, a safety device for an aerial work vehicle according to the present invention includes a travelable vehicle body, a lifting device (for example, a boom 30 in the embodiment) attached to the vehicle body so as to be lifted and lowered, and a lifting device. A work table that is attached to the operator and on which an operator can board, operating means for operating the lifting device (for example, the operating device 50 in the embodiment), and operation of the lifting device based on an operation signal from the operating means And a distance detection means (for example, a valve control unit 71 of the controller 70 in the embodiment) and a distance detection means (provided on the work table) for detecting a separation distance from the work table to an object above the work table. For example, the distance measuring sensor 60 in the embodiment)
And an alarm means for performing an alarm operation when the separation distance is equal to or less than a _first distance threshold value (for example, the warning distance TD _{1 in the} embodiment), and a second value whose separation distance is smaller than the first distance threshold value. When the distance threshold (for example, the dangerous distance TD _{2 in the} embodiment) is less than or equal to the restriction determination means for restricting the operation of the lifting device in the direction in which the work table approaches the object (for example, the restriction determination of the controller 70 in the embodiment) Part 73) and restriction release command means (for example, release switch 54 in the embodiment) operated to release the operation restriction of the lifting device by the restriction determination means
When the restriction release command means is operated in a state where the operation of the lifting device is restricted by the restriction judgment means, the work table corresponding to the operation signal from the operation means is moved away from the object. The operation of the lifting device is allowed, and the alarm operation of the alarm means is continued until the separation distance exceeds the first distance threshold.

In the safety device for an aerial work vehicle having the above-described configuration, when the lifting device is operated in a direction in which the work table approaches the object when the separation distance is equal to or less than the first distance threshold, It is preferable that the operating speed of the lifting device according to the operation signal is decelerated according to the separation distance.

Further, the safety device for an aerial work vehicle having the above-described configuration includes selection means (for example, a foot switch 53 in the embodiment) that selectively switches between valid / invalid of the operation operation by the operation means, and the alarm means is selected by the selection means. It is preferable that an alarm is activated when the operation of the operation means is effectively switched.

Further, in the safety device for an aerial work vehicle having the above-described configuration, the work table in a state where the distance detecting means is housed and held in a substantially cylindrical holding member (for example, the mounting bracket 61 in the embodiment) having an opening in the detection direction. It is preferable that it is attached to.

The safety device for an aerial work vehicle according to the present invention includes a distance detection unit provided on a workbench, a separation distance between the workbench and an object detected by the distance detection unit, and two preset distances. The distance threshold is compared with each other, and when the separation distance reaches the first distance threshold, the warning means is activated to alert the operator and the separation distance reaches the second distance threshold. In such a case, the operation of the lifting device is restricted. Therefore, when an operator is on the work table, it is possible to prevent the work table and the worker who is on it from getting too close to the object in an unintended state. The operator can be prevented from being sandwiched between the structure (object) and the safety of the operator can be ensured, and the worker has excessive distance to the object K as before. It is possible to concentrate on the original work without having to pay attention to the above, so that the burden on the operator can be reduced and the work efficiency can be improved.

In addition, in the state where the separation distance has reached the second distance threshold, the operation of the lifting device in the direction of moving the work table away from the target object is permitted when the restriction release command means is operated. Even if the operation of the lifting device in the direction that causes the work table to approach the object by mistake, the operation restriction of the lifting device in this unsafe direction will continue, Since the work board on which the user is boarded can be moved away from the object and retreated to a safe position without getting stuck, the safety of work can be further improved. In addition, since the alarm operation by the alarm means is continued until the separation distance exceeds the first distance threshold, it is possible to always alert the worker by recognizing the dangerous situation.

Further, when the separation distance is equal to or less than the first distance threshold, when the lifting device is operated in a direction in which the work table approaches the object, the operation speed of the lifting device according to the operation signal from the operation means is separated. When it is necessary to move the work table closer to the object than the first distance threshold, by decelerating according to the distance (as the work table approaches the object), Since the position of the workbench can be gradually brought closer to the object, the workbench can be moved to a desired high position while ensuring the safety of the work, and a preferable control mode from the viewpoint of safety is provided. can get.

In addition, when the separation distance is equal to or less than the distance threshold, the alarm distance by the alarm means is performed on the condition that the operation of the operation means is effectively switched by the selection means. If the alarm operation by the alarm means is always continued when the distance is equal to or less than the first distance threshold, the meaning of the danger notification to the operator may be lessened, or there may be annoying the neighborhood due to the alarm buzzer sound. In the state where the operation operation is disabled, the alarm operation is stopped, so that it is possible to surely alert the worker and prevent noise to the surroundings. At this time, when the selection means is operated to the effective side, an alarm is activated by the alarm means even if the operation means is not operated. Therefore, it is safe for an operator who is going to operate the lifting device from now on. Thorough operation can be achieved.

In addition, the distance detecting means is attached to the work table in a state where it is accommodated and held in a substantially cylindrical holding member having an opening in the detection direction so that it is difficult to receive external loads and impacts. It is possible to prevent malfunctions and ensure long-term reliability for distance detection.

It is a block diagram which shows the structure of the safety device which concerns on 1st Embodiment of this invention. It is a side view which shows the aerial work vehicle carrying the said safety device. It is a perspective view which shows the operating device with which the work platform of the said high work platform is equipped. It is a top view which shows arrangement | positioning of the ranging sensor with which the said workbench is equipped. It is a schematic diagram showing the relationship between the separation distance and the distance threshold, where (a) is warning distance <separation distance, (b) is danger distance <separation distance ≦ warning distance, and (c) is separation distance ≦ danger distance. Indicates. It is a flowchart which shows the control content of the said safety device. It is a block diagram which shows the structure of the safety device which concerns on 2nd Embodiment of this invention. It is a graph which shows the relationship between the separation distance to a target object, and the operating speed of a boom in 2nd Embodiment. It is a flowchart which shows the control content of the safety device which concerns on 2nd Embodiment.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows an aerial work vehicle (boom type work vehicle) to which the safety device according to the present embodiment is applied. First, an overview of the overall configuration of the aerial work vehicle 1 will be described with reference to FIG.

The aerial work vehicle 1 includes a vehicle body 10 of a truck-type vehicle that includes traveling tire wheels 11, 11,... That can be operated by a driving cab 12, and a swivel base 20 provided on the vehicle body 10.
A telescopic boom (hereinafter simply referred to as a “boom”) 30 having a base end portion supported via a foot pin 22 on an upper portion of a support column 21 extending upward from the swivel base 20; And a work board 40 for boarding an operator attached to the tip.

The swivel base 20 is attached to the rear part of the vehicle body 10 so as to be rotatable 360 degrees around the vertical axis. A turning motor 23 is provided inside the vehicle body 10. By turning the turning motor 23, the turntable 20 can be horizontally turned through a gear (not shown). The boom 30 has a configuration in which a proximal boom 30a, an intermediate boom 30b, and a distal boom 30c are assembled in a nested manner, and each boom 30a, 30b, 30c is operated by an expansion / contraction operation of an expansion / contraction cylinder 31 provided therein. The boom 30 can be expanded and contracted in the axial direction. Further, a hoisting cylinder 24 is straddled between the base end boom 30a and the column 21 of the swivel base 20. By operating the hoisting cylinder 24 to extend and contract, the entire boom 30 is raised and lowered within the vertical plane. Can do. Here, boom 30
Is a three-stage expansion / contraction configuration, but may be a two-stage or four-stage or more multi-stage expansion / contraction configuration.

A boom head 32 is attached to the distal end portion of the distal end boom 30c, and the lower end portion of the vertical post 33 is pivotally supported by the boom head 32. The vertical post 33 is controlled to swing by a leveling device (not shown) disposed between the tip of the tip boom 30c or between the boom head 32 and the vertical post 33, and the vertical post 33 is controlled regardless of whether the boom 30 is raised or lowered. The post 33 is always held in a vertical posture.

The work table 40 has a substantially box shape with an upper end opened, and is rotatably attached to the upper end portion of the vertical post 33 via a work table holding bracket 41 that protrudes to the outside. A swing motor 42 is provided inside the worktable holding bracket 41, and the entire worktable 40 is swung around the vertical post 33 (horizontal swivel motion) by rotating the swing motor 42. be able to. Here, since the vertical post 33 is always maintained in the vertical posture as described above, as a result, the floor surface of the work table 40 is always held horizontally regardless of the undulation angle of the boom 30.

The work table 40 is provided with an operation device 50 that is operated by an operator on the work table 40. A boom operation lever for performing a movement operation of the work table 40, that is, raising / lowering, extending / contracting and turning of the boom 30 is performed. 51 and a work table operation lever 52 for swinging the work table 40 are provided (see FIG. 3). An operator who has boarded the work table 40 operates the boom operation lever 51 and the work table operation lever 52 to extend and retract the hoisting cylinder 24, extend and retract the expansion cylinder 31, rotate the turning motor 23, and Each operation of the rotation operation of the swing motor 42 can be performed. Here, the boom operation lever 51 can be twisted in both the left and right directions around the axis in addition to the tilting operation in the front and rear direction and the left and right direction. This operation corresponds to the operation (extension / retraction operation operation of the hoisting cylinder 24), and the tilting operation of the boom operation lever 51 in the left / right direction corresponds to the expansion / contraction operation of the boom 30 (extension operation operation of the expansion / contraction cylinder 24). The twisting operation corresponds to the turning operation of the boom 30 (the turntable 20) (the rotation operation operation of the turning motor 23). The work table operation lever 52 can be tilted in the left-right direction, and the tilt operation in the left-right direction of the work table operation lever 52 is a swing operation of the work table 40 (rotation operation operation of the swing motor 42). It corresponds to.

As shown in FIG. 1, the hoisting cylinder 24 is connected to the telescopic cylinder 3 via the first control valve V1.
1 is discharged from a hydraulic pump P provided on the traveling body 10 via a second control valve V2, to the swing motor 23 via a third control valve V3, and to the swing motor 42 via a fourth control valve V4. The hydraulic oil (pressure oil) is supplied, and the undulating cylinder 24, the telescopic cylinder 31, the swing motor 23, and the swing motor 42 (hereinafter collectively referred to as “hydraulic actuator”). Are operated at directions and speeds corresponding to the drive states of the spools of the corresponding control valves V1, V2, V3, and V4. In addition, the hydraulic pump P is the traveling body 1
Operation of a predetermined hydraulic pressure and flow rate is rotationally driven using the driving force of a traveling engine E (see FIG. 1) taken out by a power take-off mechanism PTO (see FIG. 1) provided at the front of 0 Discharge the oil. Here, the drive direction of each spool of the control valves V1 to V4 is related to the drive direction (extension / contraction direction or rotation direction) of the corresponding hydraulic actuator, and the drive amount of each spool is the hydraulic oil supplied to the corresponding hydraulic actuator. It relates to the flow rate (flow rate per unit time), that is, the operating speed of each hydraulic actuator. Therefore, each control valve V1-V4
When the spool driving direction is reversed, the corresponding hydraulic actuator operating direction is reversed, and the corresponding hydraulic actuator operating speed increases as the spool driving amount of each control valve V1 to V4 increases.

A controller 70 (see FIG. 1) is installed in the traveling body 10, and the controller 7
The zero valve control unit 71 drives the spools of the control valves V1 to V3 based on operation signals output by operating the boom operation lever 51 in the respective directions (front-rear direction, left-right direction, and axial direction). Each spool of the control valve V4 is driven based on the operation signal output by operating the worktable operation lever 52. Here, the operation state (operation direction and operation amount) of the boom operation lever 51 and the work table operation lever 52 is determined by lever operation state detectors 51a and 52a (for example, configured by a potentiometer) provided in the operation device 50. The detected signal is input to the valve control unit 71 of the controller 70 as an operation signal corresponding to the operation direction and the operation amount of the operation levers 51 and 52.

With such a configuration, an operator who has boarded the work table 40 operates the boom operation lever 51 to cause the boom 30 to move up and down, extend and retract, or operate the work table operation lever 52 to hang the work table 40 on the neck. By swinging, it is possible to move the work table 40 on which it is boarded to a desired position. Outrigger jacks 13 are provided at four places on the front, rear, left and right of the traveling body 10.
The traveling body 10 can be supported in a lifted state by projecting the outrigger jack 13 downward and grounding it. In addition, each outrigger jack 13 can be extended to the side (vehicle width direction) of the traveling body 10, thereby obtaining a stable posture of the traveling body 10. The operation of the outrigger jack 13 is performed by operating a jack operating lever 14 provided behind the traveling body 10. In addition,
A PTO operation lever 15 for turning on / off the power take-off mechanism PTO (driving or stopping the hydraulic pump P) is provided at a driver seat in the driving cab 12 (see FIG. 1).

Further, the floor surface of the work table 40 is provided with a pedal-type foot switch 53 (see FIG. 1) that is operated by an operator who has stepped on the work table 40 with his / her foot.
3 is also a part of the operating device 50). The foot switch 53 is a switch that enables each hydraulic actuator to be operated by operating the boom operation lever 51 or the work table operation lever 52 only when it is being operated. Operation state)
Then, a signal (referred to as a “switch operation signal”) is output, and no switch operation signal is output in the off state (non-operation state) in which the depression is released. As shown in FIG. 1, the switch operation signal output from the foot switch 53 is input to the controller 70, and the valve control unit 71 of the controller 70 only outputs the switch operation signal from the foot switch 53. The operation signal output by operating the boom operation lever 51 and the operation signal output by operating the worktable operation lever 52 are treated as valid. Therefore,
Even if the operator on the work table 40 operates the boom operation lever 51 or the work table operation lever 52, this must be performed in a state where the foot switch 53 is depressed (the foot switch 53 is turned on). Since the operation is not effective, the operator must first depress the foot switch 53 and then operate the boom operation lever 51 or the worktable operation lever 52. Therefore, in the following, for convenience of explanation, when the boom operation lever 51 or the workbench operation lever 52 is operated, it is assumed that the foot switch 53 is always depressed and the description thereof is omitted.

The aerial work vehicle 1 having such a configuration is provided with a safety device for preventing an accident in which an operator is caught between the work table 40 and the upper structure during the aerial work. Now, the configuration of the safety device will be described in detail by exemplifying two embodiments below.

First, the configuration of the safety device according to the first embodiment will be described with additional reference to FIGS. 1 and 4 to 5. The safety device of the first embodiment includes the distance measuring sensor 6 in addition to the operation device 50 described above.
0, a controller 70, an alarm device 56, and a release switch 54. Since the operation levers 51 and 52 of the operation device 50 and the valve control unit 71 of the controller 70 have been described above, description thereof will be omitted below.

The distance measuring sensor 60 uses a laser beam, an infrared ray, an ultrasonic wave, or the like to detect the distance between the object to be detected (for example, a structure installed above the work site) K in a non-contact manner. In this embodiment, a reflective distance measuring sensor that has a light projecting unit (light projecting element) and a light receiving unit (light receiving element) in the sensor head and performs distance measurement by a triangulation system is illustrated. . The distance measurement is not limited to the triangulation method. For example, the distance is measured based on the elapsed time from when the light emitted from the light projecting unit is reflected by the object K and returns to the light receiving unit. It may be a method. In addition, the distance measuring sensor 60 is preferably one that enables long-distance measurement and is excellent in environmental resistance (such as dust proof, drip proof, vibration resistance, and shock resistance).

As shown in FIG. 4, the distance measuring sensor 60 is attached to the four corners of the outer edge of the upper opening of the work table 40 (that is, four places are installed in this embodiment), and is detected by the distance measuring sensor 60. The distance between the sensor head and the target object K can be regarded as a separation distance D between the work table 40 and the target object K substantially. Each distance measuring sensor 60 has an external load /
In order to make it difficult to receive an impact, it is attached to the work table 40 while being accommodated and held in a square tube-shaped mounting bracket 61 whose opening is directed in the detection direction (vertically upward). The distance measuring sensor 60 and the controller 70 are electrically connected, and the detection value (detection information of the separation distance D) detected by each distance measuring sensor 60 is input to the controller 70.

The controller 70 includes a valve control unit 71, a storage unit 72, a regulation determination unit 73, and a regulation release unit 74.

The storage unit 72 has a separation distance for determining whether or not the position of the work table 40 (and the worker on the work table) is too close to the object K (a risky relationship). Two distance thresholds for D, that is, warning distance TD ₁ as the first distance threshold and danger distance TD ₂ as the second distance threshold are preset and stored (provided that “danger distance TD ₂ <warning distance TD”).
₁ ”). The distance threshold (warning distance TD ₁ , danger distance TD ₂ ) may be set arbitrarily. For example, the operator may directly input a distance threshold value using a numerical key or the like, or may select from a plurality of preset values stored in advance. The distance threshold may be automatically calculated. Thereby, since the distance threshold value can be arbitrarily set according to the state of the site where the work is performed and the height of the worker, it is possible to improve workability and safety.

The restriction determination unit 73 includes the warning distance TD ₁ and the danger distance TD ₂ stored in the storage unit 72 and the detection values input from the distance measuring sensors 60 (the distance between the work table 40 and the object K at the current time). Distance D) with each other (see FIG. 5), work table 40 (and the worker on board)
It is determined whether or not there is a possibility that the object is too close to the object K. In the restriction determination unit 73, the comparison calculation is performed in parallel for each detection value of the four distance measuring sensors 60, and the detection value (four positions) of any one of the distance measuring sensors 60 is detected. When it is determined that the separation distance D) indicating the minimum value among the certain distance measuring sensors 60 is equal to or less than the warning distance TD ₁ or the dangerous distance TD ₂ , the operation restriction and alarm device 56 of the boom 30 illustrated below. The alarm action by is executed.

First, as a first stage, as shown in FIG. 5B, the restriction determination unit 73 determines that the separation distance D is equal to or less than the warning distance TD ₁ (TD ₂ <D ≦ TD ₁ ). When the object K is closer than the distance TD ₁ , an alarm activation signal is output to the alarm device 56 provided in the operation device 50 to give an alarm to the worker. For example, as shown in FIG. 3, the alarm device 56 is composed of an alarm buzzer 57, an alarm lamp 58, an alarm display 59, etc. Say anything you want. The restriction determination unit 73 self-holds the alarm activation signal while the separation distance D is equal to or less than the warning distance TD ₁ , that is, until the work table 40 is further away from the object K than the warning distance TD _1. Then, the alarm operation by the alarm device 56 is continued.

Subsequently, as a second stage, the restriction determination unit 73, as shown in FIG. 5 (c), when the separation distance D is equal to or less than the dangerous distance TD ₂ (D ≦ TD ₂ ), that is, the work table 40 is dangerous distance. When the object is closer to the object K than TD _2, a restriction signal for restricting the raising / lowering, extending / contracting and turning operation of the boom 30 is output to the valve control unit 71 to restrict the operation of the boom 30 (ie, the boom 30). 30
Forcibly stop). At this time, the valve control unit 71 that has received the restriction signal from the restriction determination unit 73 ignores the operation signal even if the boom 30 is operated (or the boom 3
By shutting off the pressure oil supply to each hydraulic actuator so that the zero operation is not performed)
The operation of the boom 30 is restricted. In addition, the regulation determining unit 73 (the separation distance D is the warning distance TD ₁
The alarm operation signal is continuously held and the alarm operation by the alarm device 56 is continued as it is (because the following state continues).

The restriction release unit 74 is electrically connected to a release switch 54 (consisting of a “momentary switch”) provided in the operation device 50, and the release switch 54 is turned on by an operator who has boarded the work table 40. An ON signal (regulation release command signal) is input only during operation (when the release switch 54 is released, it automatically returns to the neutral position and is turned off). In a state where the operation of the boom 30 is restricted (a state in which a restriction signal is output from the restriction determination unit 73), the restriction release unit 74 receives a restriction release command signal output by turning on the release switch 54. Only when the operation of the boom 30 is performed so as to move the work table 40 away from the object K (that is, in the downward direction), a restriction release signal is output to the restriction determination unit 71 (that is, The operation restriction of the boom 30 is released), and the operation of the boom 30 according to the operation state is permitted. On the other hand, when the operation of operating the boom 30 to move the work table 40 in the direction in which the work table 40 approaches the object K (that is, the ascending direction) is performed as the other operation of operating the boom 30, for example, Since it is not preferable from the viewpoint of safety, the restriction release signal is not output to the restriction determination unit 73 and the operation restriction of the boom 30 is continued.

At this time, the restriction release unit 74 moves the work table 40 away from the object K (downward) based on the operation state (operation direction) of the boom operation lever 51 detected by the lever operation state detector (potentiometer) 51a. It is determined whether or not the boom 30 has been operated so as to be moved in the direction). In addition, the boom 3 in the direction in which the work table 40 is separated from the object K.
The operation operation of 0 is, for example, an overturn operation of the boom 30 (a contraction operation operation of the hoisting cylinder 24).
, Boom 30 contraction operation (contraction operation of telescopic cylinder 31), or these booms 30
The operation of moving the work table 40 linearly in the downward direction by combining the above-described lodging operation and contraction operation is applicable. In the present embodiment, the operation restriction of the boom 30 is released when the operation of the boom 30 is performed such that the work table 40 is moved in the direction of moving away from the object K (downward direction). Even when an operation operation of the boom 30 that moves the base 40 in the direction in which the object 40 approaches the object K (upward direction) is performed, the operation restriction of the boom 30 may be released. In this case, alerting that the boom 30 is approaching the object K by changing the operation speed of the boom 30 to a low speed operation slower than normal, changing the alarm sound of the alarm operation by the alarm device 56, or both are performed. You can do it. Thereby, since it can approach to the target object K by a worker's judgment, workability | operativity improves without impairing safety.

In the aerial work vehicle 1 equipped with the safety device having such a configuration, a desired aerial work (for example,
To perform maintenance work in the road tunnel, an operator who has driven the aerial work vehicle 1 and arrived at the intended work site turns on the PTO operation lever 15 provided in the driver's seat in the driving cab 12. After operating and driving the hydraulic pump P by the driving force of the engine E taken out by the power take-off mechanism PTO, the jack operating lever 14 at the rear of the vehicle body 10 is operated to project each outrigger jack 13 to the grounded state. The vehicle body 10 is brought into a stable posture, and the vehicle body 1
Enter the work table 40 in the retracted state from 0. Then, after hooking a safety belt hook (not shown) wound around the worker's own body to the work table 40, the boom operation lever 51 in the operation device 50 is operated, and the boom 30 is raised, retracted, extended and turned. Alternatively, the work table operation lever 52 is operated to swing the work table 40. Thereby, the worker who has boarded the work table 40 can move the work table 40 to an arbitrary high position by operating his own lever and can perform a desired work at a high place.

Next, the control contents of the safety device of the first embodiment when moving the work table 40 as described above will be described below with reference to the flowchart shown in FIG.

First, when the boom operation lever 51 is operated by an operator, the boom 30 is operated at an operation direction and an operation speed corresponding to the operation state (operation direction and operation amount) of the boom operation lever 51 (step S101). When the boom 30 is activated and the work table 40 is moved, the work table 40 is moved.
Based on the detection values input from the distance measuring sensors 60 provided in the work table 40 and the object K
Is detected (step S102).

Next, the restriction determination unit 73 of the controller 70 reads the distance threshold values (TD ₁ , TD ₂ ) set in the storage unit 72, the warning distance TD ₁ as the first distance threshold value, and the distance measuring sensor 6.
The separation distance D detected at 0 is compared, and the work table 40 is more than the warning distance TD ₁ by the object K.
It is determined whether or not the vehicle is approaching (step S103). Here, when the work table 40 is farther from the object K than the warning distance TD ₁ , a negative determination is made and the warning device 56 has already been made.
If the alarm operation by the is performed, the alarm operation is canceled (step S104)
Returning to step S101, the boom 30 continues to be operated at the operation direction and operation speed corresponding to the operation state of the boom operation lever 51. On the other hand, in step S103, an affirmative determination is made, if the work bench 40 is approaching the subject K than warning distance TD _1, alarm activation is performed by the warning device 56, the alarm to the operator It is emitted (step S105).

Next, the restriction determination unit 73 of the controller 70 compares the dangerous distance TD ₂ as the second distance threshold with the separation distance D detected by the distance measuring sensor 60, so that the work table 40 has the dangerous distance T
It is determined whether or not the object K is closer than D ₂ (step S106). In this step S106, when the work table 40 is further away from the object K than the danger distance TD ₂ (that is, when the work table 40 is closer than the warning distance TD _{1 and} further away from the danger distance TD ₂ ). Is determined negative, and the alarm operation by the alarm device 56 continues and the process returns to step S101. This alarm operation is continued until it is determined in step 103 that the work table 40 is further away from the object K than the warning distance TD ₁ and thus the alarm operation is canceled in step S104. Done. On the other hand, in step S106, and in an affirmative determination is made when it is determined that the work bench 40 is approaching the subject K than risk distance TD _2, toward the restriction determination unit 73 to the valve control unit 71 regulating A signal is output, thereby restricting the operation of the boom 30 (step S107).

Next, in the restriction release unit 74 of the controller 70, the release switch 5 in the operation device 50.
It is determined whether or not 4 is turned on (step S108). Here, when the release switch 54 is not operated, the restriction release unit 74 waits for an input from the release switch 54, and until a restriction release command signal (ON signal) is input from the release switch 54, Even if the boom operation lever 51 is operated, the operation of the boom 30 is continuously restricted by the restriction determination unit 73.

When the release switch 54 is turned on by the operator, when the boom operation lever 51 is operated in the restriction release unit 74, the boom operation lever 51 is operated based on the detection information from the lever operation state detector 51a. It is determined whether or not the stage 40 has been operated in a direction (a direction away from) the object K (step S109). Here, when the boom operation lever 51 is operated in a direction in which the work table 40 is moved closer to the object K, a negative determination is made in this step S109, and the operation of the boom 30 continues to be regulated. on the other hand,
When the boom operation lever 51 is operated in a direction in which the work table 40 is moved away from the object K, the restriction release unit 74 releases the operation restriction of the boom 30 and moves the work table 4 in the direction.
Operation of the boom 30 to move 0 is permitted (step S110). As described above, when the work table 40 is closer to the object K than the danger distance TD _2, only the operation of operating the boom 30 in the direction of separating the work table 40 from the object K is permitted. By operating the boom operation lever 51 while turning on the release switch 54, the person can move the work table 40 on which he / she gets away from the object K to a safe position.

As described above, according to the safety device according to the first embodiment, the distance measurement sensors 60 are provided at the four corners of the work table 40, and the separation distance between the work table 40 and the object K detected by the distance measurement sensor 60. D is compared with a warning distance TD ₁ and a danger distance TD ₂ as distance thresholds set in advance, and when the separation distance D reaches the warning distance TD ₁ , the alarm device 56 is activated. attention to worker Te Align, when the separation distance D has reached a dangerous distance TD ₂ is configured to operate the boom 30 is restricted. Accordingly, when the operator is on the work table 40, the work table 40 and the worker who is on the work table 40 are prevented from coming too close to the object K in an unintended state. The operator can be prevented from being sandwiched between the work table 40 and the structure (object K), and the safety of the operator can be ensured. Therefore, it is possible to concentrate on the original work without excessive consideration of the distance to the operator, thereby reducing the burden on the operator and improving the work efficiency.

In a state where the separation distance D has reached a dangerous distance TD _2, since the restriction release switch 54 is when it is operated, operating the operation of the boom 30 in a direction away the platform 40 from the object K is acceptable, Even if the operator mistakenly operates the boom 30 in the direction in which the work table 40 approaches the object K, the operation restriction of the boom 30 in the unsafe direction is continued. Since the operator can move the work table 40 on which he / she is boarded away from the object K to a safe position without getting stuck, the safety of the work can be further improved. Moreover, until the separation distance D is greater than a warning distance TD ₁ for alarm activation by the alarm device 56 is continued, it is possible to arouse always attention by recognizing the dangerous situation to workers.

In addition, the distance measuring sensor 60 is attached to the work table 40 in a state of being accommodated and held in a substantially cylindrical mounting bracket 61 having an opening in the detection direction so that the distance measuring sensor 60 is less susceptible to external loads and impacts. It is possible to prevent 60 malfunctions and malfunctions and to ensure long-term reliability for distance detection.

In the above-described first embodiment, when the separation distance D is the warning distance TD ₁ or less,
When the boom 30 is operated in a direction in which the work table 40 approaches the object K, the operation speed of the boom 30 corresponding to the operation signal from the boom operation lever 51 is set according to the separation distance D (work table 40
It may be configured to decelerate the closer to the object K). According to such a configuration, when the work table 40 needs to be moved closer to the object K than the warning distance TD ₁ , the work table 40 is gradually moved closer to the object K. Therefore, the work table 40 can be moved to a desired high position while ensuring the safety of work, and a preferable control mode can be obtained from the viewpoint of safety.

Further, in the above-described first embodiment, when the separation distance D between the work table 40 and the object K is equal to or less than the warning distance TD ₁ , the above operation is performed on the condition that the foot switch 53 is depressed. You may comprise so that the alarm action | operation by the alarm device 56 illustrated in embodiment may be performed. When the separation distance D is equal to or less than the warning distance TD ₁ , as described above, if the alarm operation by the alarm device 56 is always continued, the significance of the danger notification to the worker may be diminished or the alarm buzzer sound may cause annoyance in the vicinity. Therefore, in the state where the foot switch 53 is not depressed (in the state where the foot switch 53 is turned off), the alarm operation is stopped, so that the operator can be alerted reliably and the noise to the surroundings can be ensured. Prevention can be achieved. At this time, when the foot switch 53 is depressed, an alarm is activated even if the boom operation lever 51 is not operated. Therefore, the safety awareness of the worker who will perform the operation of the boom 30 is increased. , Can ensure thorough safety operation.

Next, the configuration of the safety device according to the second embodiment will be described with additional reference to FIGS. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Here, the description will focus on the parts different from the first embodiment.

As shown in FIG. 7, the safety device of the second embodiment includes an operating device 50, a distance measuring sensor 60,
A controller 170, an alarm device 56, and a release switch 54 are included.

The controller 170 includes a valve control unit 71, a storage unit 72, a restriction determination unit 173, and a restriction release unit 174.

The restriction determination unit 173 includes the warning distance TD ₁ and the dangerous distance TD ₂ stored in the storage unit 72 and the detection values input from the distance measuring sensors 60 (the distance between the work table 40 and the object K at the current time). The distance D) is compared with each other (see FIG. 5), and it is determined whether or not there is a possibility that the work table 40 (and the worker who has boarded it) is too close to the object K. The restriction determination unit 17
3, the comparison calculation is performed in parallel for each detection value of the four distance measuring sensors 60, and the detection value of any one of the distance measuring sensors 60 (of the four distance measuring sensors 60 is detected). Among them, when it is determined that the separation distance D) indicating the minimum value is equal to or less than the warning distance TD ₁ or the danger distance TD ₂ , the speed regulation and operation regulation of the boom 30 and the alarm by the alarm device 56 are exemplified below. Operation is performed.

First, as a first stage, as shown in FIG. 5B, the restriction determination unit 173 determines that the work table 40 is in the case where the separation distance D is equal to or less than the warning distance TD ₁ (TD ₂ <D ≦ TD ₁ ). Warning distance T
A direction in which the work table 40 approaches the object K when closer to the object K than D ₁ ;
That is, in response to the movement of the work table 40 in the upward direction, a deceleration command signal is output to the valve control unit 71, and the object is determined according to the separation distance D (the closer the work table 40 is to the object K). The operation speed of the boom 30 in the direction approaching the object K is controlled to be reduced (see FIG. 8), and an alarm operation signal is output to an alarm device 56 provided in the operation device 50 to give an alarm to the worker. ,
Until the work table 40 moves away from the object K beyond the warning distance TD ₁ , the alarm activation signal is self-held and the alarm operation by the alarm device 56 is continued. At this time, the restriction determination unit 173 detects the boom operation lever 51 detected by the lever operation state detector (potentiometer) 51a.
Based on the operation state (operation direction), it is determined whether or not the operation operation of the boom 30 is performed so as to move the work table 40 in the direction in which the work table 40 approaches the object K (upward direction). The operation operation of the boom 30 in the direction in which the work table 40 approaches the object K is, for example, an operation of raising and lowering the boom 30 (extension operation operation of the hoisting cylinder 24) and an operation of extending the boom 30 (extension cylinder 3).
1 and the operation of moving the work table 40 linearly in the upward direction by combining the raising and lowering operations of the boom 30.

Here, in order to reduce the operating speed of the boom 30 as described above, a control signal is output from the valve control unit 71 to the control valves V1 to V3, and the valve opening degree (spool drive amount) of the control valves V1 to V3 is set. It is done by making small adjustments. On the other hand, even when the separation distance D is smaller than the warning distance TD ₁ , when the boom 30 is operated in a direction to move the work table 40 away from the object K by the operation of the boom operation lever 51, the valve control unit 71 and The regulation judgment unit 173
The boom 30 is operated at an original operation speed corresponding to the operation state (operation amount) of the boom operation lever 51.

Subsequently, as a second stage, as shown in FIG. 5C, the restriction determination unit 173 determines that the separation distance D is equal to or less than the dangerous distance TD ₂ (D ≦ TD ₂ ). When closer to the object K than TD _2, when the boom operation lever 51 is operated, a restriction signal for restricting the hoisting, expanding and contracting and turning operation of the boom 30 is output to the valve control unit 71. The operation of the boom 30 is restricted (that is, the operation of the boom 30 is forcibly stopped). The restriction determination unit 173 continues to keep the alarm operation by the alarm device 56 as it is by continuously holding the alarm operation signal (because the distance D is the warning distance TD ₁ or less).

At this time, the valve control unit 71 that has received the restriction signal from the restriction determination unit 173 receives the boom 30.
The operation of the boom 30 is regulated by ignoring the operation signal (or shutting off the pressure oil supply to each hydraulic actuator so that the operation of the boom 30 is not performed). .

The restriction release unit 174 is electrically connected to a release switch 54 provided in the operation device 50, and an on signal (restriction) is only applied while the release switch 54 is turned on by an operator who has boarded the work table 40. (Release command signal) is input (when the release switch 54 is released, it automatically returns to the neutral position and is turned off). The restriction release unit 174 is the boom 3
In a state where the operation of 0 is regulated (a regulation signal is outputted from the regulation judgment unit 173),
When a restriction release command signal output by turning on the release switch 54 is received, a restriction release signal is output to the restriction determination unit 173 to cancel the output of the restriction signal from the restriction determination unit 173 (that is, the boom 30 The boom control lever 5 is released.
1 is operated, a speed correction signal is output to the valve controller 71, and the operating speed of the boom 30 (the operating speed of the hydraulic actuator) is lower than the original speed corresponding to the operating amount of the boom operating lever 51. (See FIG. 8). The operating speed of the boom 30 here is controlled to be lower than the operating speed of the boom 30 controlled to be decelerated according to the separation distance D in the first stage (for example, the hydraulic pressure corresponding to the operation signal of the boom operating lever 51). The operation output gain of the actuator is corrected to a small value, and the operation speed of the boom 30 is set to a predetermined low speed controlled to be lower than the original operation speed according to the operation amount). Note that the operating speed of the boom 30 is always a constant low speed (for example, the storage unit 72) regardless of the operation amount of the boom operation lever 51.
The minimum speed set in the above) or the deceleration control according to the separation distance D between the work table 40 and the object K. As a result, the operating speed of the boom 30 may be determined. As long as the speed can be controlled to be lower than the operating speed of the boom 30 in the first stage, other means may be used.

Next, the control content of the safety device of the second embodiment will be described below with additional reference to the flowchart shown in FIG.

First, when the boom operation lever 51 is operated by an operator, the boom 30 is operated at an operation direction and an operation speed corresponding to the operation state (operation direction and operation amount) of the boom operation lever 51 (step S201). When the boom 30 is activated and the work table 40 moves, the work table 4
The separation distance D between the work table 40 and the object K is detected based on the detection value input from each distance measuring sensor 60 provided at 0 (step S202).

Next, the restriction determination unit 173 of the controller 170 reads the distance threshold values (TD ₁ , TD ₂ ) set in the storage unit 72 and detects them with the warning distance TD ₁ as the first distance threshold and the distance measuring sensor 60. The separated distance D thus compared is compared to determine whether or not the work table 40 is closer to the object K than the warning distance TD ₁ (step S203). In this step S203, if the working platform 40 is spaced from the object K than warning distance TD ₁ is made negative, release the alarm activation already when alarm activation by the alarm device 56 is running After that (step S204), the process returns to step S201, and the boom 30 is continuously operated at the operation direction and the operation speed according to the operation state of the boom operation lever 51. On the other hand, when the work table 40 is closer to the object K than the warning distance TD ₁ in step S203, an affirmative determination is made, an alarm operation by the alarm device 56 is executed, and an alarm is given to the worker. It is emitted (step S205). The alarm operation by the alarm device 56 is performed when the work table 40 has a warning distance T.
It is determined that the distance from the object K is greater than D ₁ (step S203), and the alarm operation is canceled (step S204).

Next, the restriction determination unit 173 of the controller 170 compares the dangerous distance TD ₂ as the second distance threshold with the separation distance D detected by the distance measuring sensor 60, so that the work table 40 is more than the dangerous distance TD _2. It is determined whether or not the object K is approaching (step S206). In this step S206, when the work table 40 is farther from the object K than the danger distance TD ₂ (that is, when the work table 40 is closer than the warning distance TD _{1 and} farther than the danger distance TD ₂ ). In the restriction determination unit 173, based on the detection information from the lever operation state detector 51a, it is determined whether or not the boom operation lever 51 is operated in a direction in which the work table 40 approaches the object K. Determination is made (step S207). Here, if the boom operation lever 51 is operated in a direction to move the work table 40 away from the object K, step S is performed.
A negative determination is made at 207, and the process returns to step S <b> 201 with the alarm operation being performed as it is, and the boom 30 is operated at the original operation speed corresponding to the operation amount of the boom operation lever 51. On the other hand, when the boom operation lever 51 is operated in the direction in which the work table 40 approaches the object K in step S207, the distance D between the work table 40 and the object K is determined. In other words, the closer the work table 40 is to the object K, the slower the operating speed of the boom 30 in the direction of approaching the object K (step S208).

On the other hand, in step S206, if it is determined that the distance D is approaching the subject K than risk distance TD ₂ is regulated signal is output from the restriction determining section 173 to the valve control unit 71, which Thus, the operation of the boom 30 is restricted (step S209).

Next, in the restriction release unit 174 of the controller 170, it is determined whether or not the release switch 54 in the operating device 50 is turned on (step S210). Release switch 5
4 is not turned on, the restriction release unit 174 waits for an input from the release switch 54, and the boom operation lever 51 is operated until the release of the restriction release command signal from the release switch 54. In addition, the operation of the boom 30 is continuously restricted by the restriction determination unit 173.

When the release switch 54 is turned on by the operator, the restriction release unit 174
The operation restriction of the boom 30 is released (step S211). At this time, when the boom operation lever 51 is operated by an operator who has boarded the work table 40, the boom 30 is operated in any direction (that is, any direction in which the work table 40 approaches or separates from the object). Even in such a case, the boom 30 is always operated at a predetermined low speed regardless of the operation amount of the boom operation lever 51 (step S212). Thus, the operator by operating the boom operation lever 51 while turning on the release switch 54, the object than risk distance TD ₂ workbench 40 to board itself actuates the boom 30 at a predetermined low speed K can be gradually approached.

As described above, according to the safety device according to the second embodiment, the distance measurement sensors 60 are provided at the four corners of the work table 40, and the separation distance between the work table 40 and the object K detected by the distance measurement sensor 60. D is compared with a warning distance TD ₁ and a danger distance TD ₂ as distance thresholds set in advance, and when the separation distance D reaches the warning distance TD ₁ , the direction toward the object K is approached. The boom 30
The deceleration in accordance with the operating speed that distance, if the distance D has reached a dangerous distance TD ₂ is configured to operate the boom 30 is restricted. Accordingly, since the work table 40 is prevented from being too close to the object K in an unintended state, an operator is sandwiched between the work table 40 and the structure (object K) during work at a high place. Can be ensured and the safety of the worker can be ensured, and the worker can concentrate on the original work without having to consider the distance between the work table 40 and the object K as before. Therefore, the burden on the operator can be reduced and the work efficiency can be improved.

In a state where the separation distance D has reached a dangerous distance TD _2, although it is possible to operate the boom 30 only when the release switch 54 is operated, the operating speed of the boom 30 at this time is normal working And since it is slower than the operation speed at the time of deceleration, it is possible to move the work table 40 in a direction in line with the operator's intention while ensuring safety. For this reason, for example, even when the work table 40 needs to be moved closer to the object K than the danger distance TD ₂ , the work table 40 can be positioned with fine adjustment at a low speed.
Can be prevented from coming into contact with the structure (object K) too much.

Also, an alarm device 56 that operates when the separation distance D is less than or equal to the distance threshold values TD ₁ and TD _2.
The provided, when the working operation of the boom 30 in the direction approaching the object K is performed in a state where the distance D has reached the warning distance TD _1, gives a predetermined alarm by the warning device 56 to workers Thus, the operator can be informed that the work table 40 is closer to the object K than the warning distance TD ₁ , and the worker who has received this warning is in an unsafe direction (that is, to the object K). It is possible to pay close attention to the movement of the work table 40 in the approaching direction. On the other hand, when the separation distance D reaches the dangerous distance TD ₂ , the separation distance D becomes the dangerous distance T
The alarm device 56 is continuously operated until it is farther from the object K than D ₂ , and the worker is made aware of the situation and always alerts him, so that work safety can be further improved.

The preferred embodiments of the present invention have been described so far, but the scope of the present invention is not limited to those shown in the above-described embodiments. For example, in the above-described embodiment, the detection value (the separation distance between the work table 40 and the object K at the present time) input from the distance measuring sensor 60 is compared with the distance threshold value. The detection means for detecting the tip position of the boom 30 (the position of the work table 40) is provided with a undulation angle detector, an expansion / contraction amount detector, and a turning angle detector. The predicted movement trajectory of the workbench 40 is calculated based on the detected value (the position of the workbench 40) and the operation signal from the boom operation lever 51, and the predicted movement trajectory and the detected value from the distance measuring sensor 60 (current time). The predicted distance between the work table 40 and the object K when the work table 40 is moved is calculated based on the separation distance between the work table 40 and the object K in FIG. Comparison operation with Based on the results, it may be configured to perform such operation restriction of the boom 30.

In the above-described embodiment, the distance measuring sensors 60 are installed at the four corners of the outer edge of the upper opening of the workbench (
That is, four distance measuring sensors are installed), but the present invention is not limited to this, and distance measuring sensors 60 are installed at the four corners of the inner edge of the upper opening of the work table or along the outer edge of the upper opening. 4
The distance measuring sensor 60 may be installed at a plurality of locations more than the location. Here, the distance measuring sensor 60
The mounting position of the work table 4 is not disturbed when the operator gets on or off the work table 40.
It is preferable to remove the area from the zero boarding area. Further, the detection directions of the distance measuring sensors 60 installed at a plurality of locations are not necessarily limited to the vertical upward direction, and may be directed in a plurality of directions (diagonally upward directions) with respect to the vertical axis, for example. Note that the distance measuring sensor 60 does not necessarily have to be installed at a plurality of locations, and may be installed at only one location.

Further, as a safety measure in case of malfunction of the distance measuring sensor 60, a metal guard member is provided on the upper edge of the work table 40, and even when the work table 40 is too close to the structure, You may make it prevent a worker contacting a structure. The height of the guard member (the amount of protrusion from the upper edge of the workbench) is, for example, about 40 centimeters, but can be adjusted (extendable) according to the height of the worker. It doesn't matter.

In the above-described embodiment, the boom 30 is operated by operating the boom operation lever 51.
Is operated to freely move up and down, extend and retract, but the operation device 50 has a mode selection switch for selecting and operating either the normal mode or the horizontal / vertical operation control mode (referred to as “HV mode”). It may be provided to operate the boom 30 according to one of two operation control modes. The normal mode is a mode in which the hydraulic actuators can be operated individually or simultaneously by operating the boom operation lever 51. The HV mode is a mode in which the hydraulic actuators are operated in conjunction with each other by operating the boom operation lever 51. Boom 30
This is a mode in which the front end portion (including the work table 40) can be moved linearly in the horizontal direction or the vertical direction. Here, when the mode selection switch is selected to the HV mode side, the operator operates the operation lever 51 to linearly move the work table 40 (the tip of the boom 30) vertically upward, The work table 40 can be made to approach the target object K (upper structure) more efficiently than in the normal mode, but on the other hand, the work table 40 approaches the object K in a short time. There is a risk of overdoing it. Even in such a case, according to the safety device of the above-described embodiment, even when the boom 30 is operated according to the HV mode, the work table 40 is prevented from being too close to the object K in an unintended state. Therefore, it is effective because it is possible to prevent the operator from being caught between the work table 40 and the upper structure (object K) during work at high places, and to ensure the safety of the operator. .

In the above-described embodiment, the object to which the present invention is applied is a work vehicle whose body is a tire wheel type, but the vehicle body is not necessarily limited to a tire wheel type, and travels by a crawler device or the like. It may be a thing. Alternatively, it may be an orbital working vehicle that includes an orbital traveling wheel and travels on an orbital track, and further, an orbital working vehicle that includes both a tire wheel and an orbital traveling wheel.

In the above-described embodiment, the lifting device attached to the vehicle body of an aerial work vehicle has been described as an example of an extendable boom that can be raised, lowered, extended, and turned. Further, the lifting device is not limited to the one that can move the work table three-dimensionally, such as the boom, but can be a device that can only lift and lower the work table vertically, such as a scissor-link lifting device. There may be.

1 aerial work platform 10 car body 30 boom (lifting device)
40 work table 50 operation device (operation means)
51 Boom operation lever (operation means)
53 Foot switch (selection means)
54 Release switch (regulation release command means)
56 Alarm device (alarm means)
60 Ranging sensor (distance detection means)
61 Mounting bracket (holding member)
71 Valve control unit (operation control means)
72 Storage Unit 73 Restriction Judgment Unit (Regulation Judgment Unit)
74 Restriction release part (Release release means)
K object D separation distance TD distance threshold (TD ₁ : first distance threshold, TD ₂ : second distance threshold)

Claims (4)

A vehicle body that can travel,
A lifting device attached to the vehicle body so as to be movable up and down;
A worktable attached to the lifting device and on which an operator can board;
Operating means for operating the lifting device;
An operation control means for controlling the operation of the lifting device based on an operation signal from the operation means;
A distance detecting means provided on the workbench for detecting a separation distance from the workbench to an object above the workbench;
Alarm means for performing an alarm operation when the separation distance is equal to or less than a first distance threshold;
Restriction judging means for restricting the operation of the lifting device in a direction in which the work table is brought closer to the object when the separation distance is equal to or smaller than a second distance threshold value smaller than a first distance threshold value;
A restriction release command means operated to release the operation restriction of the lifting device by the restriction determination means,
A direction in which the work table according to an operation signal from the operation means is moved away from the object when the restriction release command means is operated in a state where the operation of the lifting device is restricted by the restriction determination means. An aerial work vehicle characterized in that the operation of the lifting device is allowed to continue and the alarm operation of the alarm means is continued until the separation distance exceeds the first distance threshold. Safety device. When the lifting / lowering device is operated in a direction in which the work table approaches the object when the separation distance is equal to or less than the first distance threshold, the lifting / lowering device according to an operation signal from the operation means The safety device for an aerial work vehicle according to claim 1, wherein the operating speed of the vehicle is decelerated in accordance with the separation distance. Comprising selection means for selectively switching between valid / invalid of the operation operation by the operation means,
The safety device for an aerial work vehicle according to claim 1 or 2, wherein the warning means is activated when the operation of the operation means is effectively switched by the selection means. The distance detection means is attached to the work table in a state of being housed and held by a substantially cylindrical holding member having an opening in the detection direction. Safety equipment for aerial work platforms.

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