JPH0721512Y2 - Boom operation control device for aerial work vehicles - Google Patents

Description

[Detailed Description of Device] a. Purpose of the Invention (Field of Industrial Use) The present invention relates to a device for restricting the operation of a boom which is mounted on an aerial work vehicle and is capable of freely elevating and retracting.

(Prior Art) Work vehicles such as aerial work vehicles and mobile cranes are equipped with a boom that can be undulated, extended and retracted, and by operating this boom, the work platform attached to the boom tip or the weight suspended. Move objects to any height or position. In such a work vehicle, in order to improve work efficiency, it is often desirable to make the operable range of the boom, that is, the work range as wide as possible. In the working range, the falling side moment acting in the falling direction on the work vehicle is projected to the side of the vehicle body due to the weight of the boom and the workbench (including the operator) or the suspended object. It is set so that the rated moment that can be supported by the outrigger is not exceeded.

By the way, using a work platform for aerial work,
When working at heights higher than m), the worker requires a special license. Therefore, in the past, unlicensed workers used aerial work vehicles with the boom length limited so that the lift at maximum undulation would be the specified height when the boom was fully extended. Was there.

(Problems to be solved by the invention) However, in the aerial work vehicle in which the maximum length of the boom is limited according to the specified height as described above, the boom is operated only within a narrow range corresponding to the maximum length. However, there is a problem in that the efficiency of work cannot be improved.

In view of the above problems, according to the present invention, when the lift reaches the specified height, the boom operation in the direction in which the lift is further increased is restricted, while when the lift is less than the specified height, the boom is freely undulated. It is an object of the present invention to provide a boom operation restricting device for an aerial work vehicle that can be extended.

B. Configuration of the Invention (Means for Solving the Problems) In order to achieve the above object, in the present invention, the lift detecting means detects the lift of a work platform attached to the tip of the boom, and the restricting means detects the lift. When it is determined that the lift of the workbench has reached a predetermined height based on the detection signal from the means, the operation of the boom in a direction to further raise the lift of the workbench is restricted. .

(Operation) In such a boom operation restricting device for an aerial work vehicle, when the lift of the work platform detected by the lift detecting means is less than the predetermined height, the restricting means does not restrict the operation of the boom and the boom does not move. It can be extended to the fully extended state. However, when the above-described detected lift reaches a predetermined height, even if the boom originally has the ability to have a higher lift, the boom operation in such a high lift direction (raising / lowering operation and extension) is performed by the operation of the restricting means. Operation). However, boom operation in the direction of lowering the lift is permitted.

(Embodiment) Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

First, FIG. 3 shows an aerial work vehicle equipped with a boom operation restricting device according to the present invention. A swivel base 2 is mounted on a vehicle body 1 of this aerial work vehicle. This swivel base 2
The turning of the vehicle body 1 is made possible by the operation of the turning motor 3 operated by hydraulic pressure. Further, a base end portion of a telescopic boom 4 in which a tip boom 4b is fitted in a base end boom 4a is pivotally attached to the swivel base 2. The boom 4 can be lifted and lowered by expanding and contracting a hydraulically operated hoisting cylinder 5 arranged between the swivel base 2 and the base end boom 4a. Further, the tip boom 4b can be expanded and contracted by the expansion and contraction operation of the hydraulically operated expansion and contraction cylinder 6 mounted inside the boom 4. A bucket (workbench) 7 for mounting an operator is attached to the tip of the tip boom 4b.

Therefore, by operating the turning motor 3, the hoisting cylinder 5, and the telescopic cylinder 6 based on the lever operation of the operator, the bucket 7 can be moved to a desired position and high-altitude work can be performed. A leveling device (not shown) is provided between the bucket 7 and the telescopic boom 4, and the leveling device keeps the bucket 7 horizontally during the work. Further, outriggers 8 are provided at four positions on the front, rear, left and right of the vehicle body 1. When performing work, these outriggers 8 are extended to the side of the vehicle body 1 and extended downward to support the vehicle body 1.

The boom 4 of the aerial work vehicle having such a configuration is controlled by the boom operation restricting device shown in FIG.

This device is composed of a lift detection unit 11 and a restriction unit 12.

The lift detection unit 11 includes an undulation sensor 13 and an extension sensor 14, and these sensors 13 and 14 detect the undulation angle and extension amount of the boom 4, respectively, and output detection signals.

The restriction unit 12 includes a calculator 15, a controller 16, an operation direction detector 17, and a valve unit 18. The detection signals from both the sensors 13 and 14 are input to the arithmetic unit 15, and the arithmetic unit 15 determines the bucket 7 based on these detection signals.
The lift (height from the ground to the bottom surface of the bucket 7) is calculated. This calculated head is sent to the controller 16. The operation direction detector 17 detects the operation direction of the operation lever for operating the boom 4, that is, the up / down direction, the down direction, or the extension direction or the contraction direction. This operation direction detection signal is also sent to the controller 16. Controller 16
Then, based on the above-described calculated lift and operation direction detection signal, when the calculated lift reaches the specified height, it is determined that the lift is further increased, that is, if it is determined that the lift has been operated in the up-and-down direction or the extension direction. In order to restrict the boom operation, a restriction signal is sent to the valve unit 18 that controls the supply and discharge of hydraulic oil that operates the undulating cylinder 5 and the telescopic cylinder 6. Electromagnetic valves for the cylinders 5 and 6 are provided in the valve unit 18, and the restriction signal excites the solenoids of these valves to deactivate the cylinders 5 and 6.

In addition, the above-mentioned prescribed height refers to the working height, etc. at which a worker is required to have a special license when working at a height higher than this by the law.

Next, the operation of this device will be described with reference to FIG.

When the hoisting angle of the boom 4 is less than or equal to the angle α, even if the boom 4 is maximally extended, the lifting height of the bucket 7 is less than or equal to the specified height Ha, so the boom 4 is free in the region I where the hoisting angle is less than or equal to the angle α. The undulation and expansion / contraction operation can be performed. Therefore, the detected undulation angle detected by the undulation sensor 13 is the angle α.
In the following cases, the control signal is not output from the controller 16.

In the region II where the undulation angle exceeds the angle α, the lift of the bucket 7 may exceed the specified height Ha depending on the extension amount of the boom 4. Therefore, for example, when the boom 4 is raised and lowered from within the area I, the levitation sensor 13 and the extension and contraction sensor
When it is determined that the calculated head calculated by the calculator 15 based on the detection signal from 14 has reached the specified height Ha, the controller 16 outputs a regulation signal to prevent the head from further increasing. . However, after this, when the operator operates the operation lever and the operation direction detected by the operation direction detector 17 is the direction to maintain or lower the lift of the specified height Ha, the controller 16 regulates. The signal is released and the boom 4 is operated in that direction.

By restricting the operation of the boom 4 in this way, as shown by the dotted line CUT in the figure, compared to the case where the maximum length of the boom 4 is limited from the beginning to the length that becomes the specified height at the maximum hoisting angle, The work range can be widened only by the range of parts.

It is also possible to use a plurality of limit switches instead of the undulation sensor 13, the extension sensor 14, and the computing unit 15 of this example, and to output the restriction signal to the controller 16 by combining the signals from these limit switches. Hereinafter, this example will be described.

As shown in FIG. 4, the first and second undulation limit switches LS1 and LS2 that are turned on and off at a predetermined undulation angle, and the first and second expansion and contraction limit switches LS3 that are turned on and off at a predetermined extension amount. , LS4 are arranged on or near the boom 4. The first undulating limit switch LS1
When the boom 4 is in the fully extended state and the lift is less than the angle α at which the height is the specified height Ha, the boom 4 is turned off and outputs a signal “0”. The second hoisting and lowering limit switch LS2 has a hoisting height of Ha when the hoisting angle is one step shorter than the fully extended state of the boom 4 (boom length corresponding to the switching position of the first telescopic limit switch LS3). When the angle is less than β, the signal turns off and the signal "0"
Is output. When the angle is β or more, the signal is turned on and the signal “1” is output. The first telescopic limit switch LS3 is turned off and outputs a signal "0" when the boom length is the first step shortened length L ₁ or less where the lift is the specified height Ha when the hoisting angle is the angle β. , When the first step shortened length L ₁ is exceeded, it is turned on and the signal “1” is output. In addition, the second extension limit switch
LS4 turns off when the boom length is the second step shortening length L ₂ or less at which the lifting height reaches the specified height Ha when the hoisting angle is maximized, and outputs a signal "0" to shorten the second step. When it exceeds the length L ₂ , it turns on and outputs the signal "1".

The signals from the limit switches LS1 to LS4 are fetched into the controller 16 and the raising and lowering operation of the boom 4 is restricted by the combination shown in FIG. That is, when the hoisting angle of the boom 4 is less than the angle α (region I ′), both the first and second hoisting limit switches LS1 and LS2 are off (LS1 = 0, LS2 = 0). In this case, since the lifting height does not exceed the specified height Ha even when the boom 4 is fully extended, regardless of the boom length, that is, the first and second telescopic limit switches LS3 and LS4 are turned on / off. The boom 4 can be operated freely regardless of the situation. Therefore, the controller 16 does not output a restriction signal for restricting the hoisting operation (see the first to third stages in FIG. 5).

If the undulation angle is greater than or equal to the angle α and less than β (region II ′), the first
Only the undulation limit switch LS1 is turned on and the second undulation limit switch LS2 is turned off (LS1 = 1, LS2 =
0). In this case, when the boom length exceeds the first-stage shortened length L ₁ , the first and second telescopic limit switches LS3, LS4
Are both on (LS3 = 1, LS4 = 1), and in such a case, the hoisting and extending operations of the boom 4 are restricted. However, if the boom length is shortened to the first-stage shortened length L ₁ or less and the first extension limit switch LS3 is turned off (LS3 = 0), the boom is turned on regardless of whether the second extension limit switch LS4 is on or off. 4 can be raised and lowered and extended (see steps 4 and 5 in FIG. 5).

When the undulation angle is equal to or larger than the angle β (region III ′), both the first and second undulation limit switches LS1 and LS2 are turned on (LS1 = 1, LS2 = 1). In this case, when the boom length exceeds the second-stage shortened length L ₂ , the second expansion / contraction limit switch LS4 is on (LS4 = 1), and in such a case, the first extension limit switch LS4 is on.
Regardless of whether the expansion / contraction limit switch LS3 is on or off, the boom 4 is restricted from raising and lowering operations and extending operations (see the eighth and ninth steps in FIG. 5). However, if the boom length is shortened to the second stage shortening length L ₂ or less and the second extension limit switch LS4 is off (LS3 = 0, LS4 = 0), the boom 4 is hoisted to the maximum hoisting angle. Alternatively, the extension operation can be performed (see the seventh step in FIG. 5).

By restricting the hoisting and hoisting operation of the boom 4 as described above, the work range can be widened by the range of the hatched portion as compared with the case where the maximum length of the boom 4 is limited from the beginning (dotted line CUT), as in the previous example. In this example, the area other than the area I'where the boom 4 can be freely operated is divided into two areas II 'and III', and as a result, the bucket 7 is moved even in the working range of the specified height Ha or less. Area I cannot
Although I ″ and III ″ are generated, the moving range of the bucket 7 can be brought close to the entire working range as described above by dividing the region into smaller regions.

C. Effects of the Invention As described above, by using the boom operation restricting device of the present invention, in an aerial work vehicle equipped with a boom having a lifting capacity of a predetermined height or higher, the lift of the workbench is limited to the predetermined height or lower. On the other hand, if the lifting height is below a predetermined height, the boom can be hoisted and extended freely, so the maximum length of the boom is set to the length at which the lifting height reaches the predetermined height at the time of maximum hoisting from the beginning. The work range can be made wider than the restricted one, and the work efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a boom operation restricting device according to the present invention, FIG. 2 is a schematic view showing a working range when the boom operation restricting device is used, and FIG. An aerial work vehicle equipped with a boom operation restricting device, FIG. 4 is a schematic view showing a configuration and a working range of the second embodiment of the boom operation restricting device, and FIG. 5 is a schematic view showing the second embodiment. 7 is a chart showing combinations of signals from limit switches. 4 ... Boom, 7 ... Bucket 11 ... Lift detection section, 12 ... Restriction section LS1 ... 1st undulation limit switch LS2 ... 2nd undulation limit switch LS3 ... 1st extension limit switch LS4 ... 2nd extension limit switch

Claims (1)

[Scope of utility model registration request] 1. A boom operation restricting device for an aerial work vehicle, comprising a boom capable of at least undulation and extension and contraction, and having a work platform at a tip of the boom, and a lift detecting unit for detecting a lift of the work platform. When it is determined that the lift of the work table has reached a predetermined height based on the detection signal from the lift detection means, the boom is operated in a direction to further raise the work table. A boom operation regulating device for an aerial work vehicle, comprising a regulating means for regulating.