JPH10167698A - Safety device of service car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure an extensive working range upon preventing the interference among a workbench, a boom and a driver's cab by installing control means regulating a turning motion in this boom at the time when it reaches a turning regulating area from each detected value by an expansion length detector of the boom, a turning angle detector and a derricking angle detector. SOLUTION: An expansion length detector 11 detects the expansion length of a boom, and a turning angle detector 12 and a derricking angle detector 13 detect the boom angle respectively. A computing element 14 is composed of regulation area setting means 16, selective means 17 and control means 18. The judgment of regulation takes place from a position of the boom detected, and in the case of this regulation, a single is outputted to a turning regulating device 15, thereby regulating any turning motion in the boom. A turning regulating area of the boom presets both first and second turning regulating area by length of the boom and its turning angle. In succession, the control means 18 outputs a regulating signal to the turning regulating device 15 when coming to the regulating area from the selected turning regulating area and the detected turning angle, whereby regulating the tuning operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work vehicle equipped with a workbench at the end of a boom such as a workbench, and a safety device for the work vehicle for preventing the boom and the workbench from interfering with a driver's cab. About.

[0002]

2. Description of the Related Art When performing an aerial work using an aerial work vehicle, if the boom is turned forward toward the front of the vehicle in a state where the boom is lying down to a substantially horizontal position, the boom or the workbench is operated at a height. May interfere with the driver's cab at the front of the car. For this reason, the up-and-down angle and turning angle of the conventional boom are detected,
There is a safety device for preventing the interference by providing a safety device for stopping the operation of the boom at a position before the boom or the like interferes with the cab. (See Japanese Patent Publication No. 6-99118)

[0003]

However, in the conventional safety device, the work table does not swing with respect to the boom, and only the interference between the boom and the cab is prevented. Therefore, in the above safety device,
When used in a work vehicle equipped with a swingable work platform at the end of the boom, interference between the boom and the driver's cab can be prevented. There was a risk of interference. Further, when the turning restriction area is widened in order to prevent interference between the worktable and the cab, there is a problem that the working range is narrowed. In view of the circumstances described above, an object of the present invention is to provide a safety device for a work vehicle that prevents interference between a workbench and a boom and a driver's cab and provides a wide work range.

[0004]

In order to solve the above-mentioned object, a safety device for a work vehicle according to the present invention comprises a telescopic length detecting means for detecting a telescopic length of a boom, and a turning angle of the boom. Turning angle detecting means, hoisting angle detecting means for detecting the hoisting angle of the boom, and when the boom has an hoisting angle equal to or lower than the upper end of the cab, the boom expansion and contraction length is equal to the workbench and the cab. When a predetermined amount or more that does not interfere, a turning area where the boom and the cab interfere with each other due to the turning of the boom is set as a first turning restriction area,
When the length of expansion and contraction of the boom is equal to or less than the predetermined amount at which the workbench and the cab interfere with each other, a swivel region where the worktable and the cab interfere with each other due to the swing of the boom is set to a second swivel restriction region And a first turning restriction area set in the restriction area setting means based on a signal from the expansion / contraction length detecting means, and one of a second turning restriction area and the expansion / contraction length of the boom. The boom has an elevation angle equal to or less than the upper end of the driver's cab and is selected by a signal from the selection means, the elevation angle detection means, and the turning angle detection means. And control means for restricting the further turning movement of the boom when it reaches the turning restriction area.

Further, the safety device for a work vehicle having the above structure is provided with a swing angle detecting means for detecting a swing angle of the work table, and when the boom has an up-and-down angle below the upper end of the cab, When the telescopic length of the boom is equal to or more than a predetermined amount that does not cause interference between the workbench and the cab, the telescopic length of the boom is equal to or less than the predetermined amount, and the workbench operates from the axis of the boom. When it is located on the opposite side to the room, a turning area where the boom and the cab interfere with each other due to the turning of the boom is set as a first turning restriction area, and the length of expansion and contraction of the boom is such that the working table and the cab When the work platform is located closer to the cab side than the axis of the boom, the swivel of the boom causes the swivel region where the work platform and the cab interfere with each other to perform a second swing. Set as restricted area And as to constitute the selection means to select in accordance with the first turn restriction region and the second pivot restricting area stretch length and worktable swing angle of the boom.

In addition to the above-mentioned control means, when the turning position of the boom reaches the selected turning restricting region, the control means restricts the further turning movement of the boom.
When the turning control area is selected, the reduction movement of the boom below a predetermined amount is restricted, and when the selecting means selects the second turning restriction area, the further reduction movement of the boom is restricted. Is also configured.

[0007] In addition to the above-mentioned control means, when the turning position of the boom reaches the selected turning restricting region, the control means restricts the further turning movement of the boom.
Is selected, and when the length of expansion and contraction of the boom is equal to or less than the predetermined amount, the workbench is configured to restrict the swinging operation in the direction of the cab beyond the axis of the boom. I have.

[0008]

By using such a safety device, even if the boom is turned down and turned or the worktable is swung, the boom turning motion is stopped before interfering with the cab, so that interference can be prevented. At the same time, the operator does not need to pay attention to interference with the driver's cab, so that the operation becomes easier. In addition, by providing two turning restriction areas and finely controlling them, it is possible to extend the working range without restricting the turning of the boom at an unnecessary position, and to obtain a boom working vehicle that is easier to use. .

[0009]

Preferred embodiments of the present invention will be described below with reference to the drawings. First, an aerial work vehicle (work vehicle) provided with the safety device according to the present invention will be described with reference to FIGS. The aerial work vehicle 1 is provided with a driver's cab 3 in front of a vehicle body 2 and performs a traveling operation of the aerial work vehicle 1. Outrigger jacks 8 are provided at four locations on the front, rear, left and right sides of the vehicle body 2 so as to extend laterally of the vehicle body 2 and extend downward to stably support the vehicle body 2. On the other hand, a turning table 4 is provided at the rear of the vehicle body 2 so as to be able to turn the vehicle body 2 by operating a hydraulic motor (not shown) or the like. Not shown)
A boom 5 configured to be extendable and contractable by the operation of a telescopic device such as
Is pivoted by the operation of. The tip of the boom 5 is always horizontal by the operation of a motor (not shown) or the like, and is always horizontal by the operation of a balancing device such as a hydraulic cylinder (not shown) irrespective of the movement of the boom. A work table 6 is provided so as to be held. On the work table 6,
An operator can board, and the operator
By operating an operation unit (not shown) provided above, the swivel of the swivel base 4 (hereinafter referred to as “boom swivel” for convenience) and the boom 5 can be moved up and down to extend and retract. You can move and work.

By the way, in general, in the aerial work vehicle 1, the boom 5 can be tilted at a negative angle from the horizontal line in order to improve getting on and off the work table 6. For this reason, if the boom 5 is turned down below the substantially horizontal position and turned forward of the vehicle body 2, the boom 5 or the workbench 6 may interfere with the cab 3. Therefore, in order to prevent such an interference accident, the safety device of the present invention is attached to the aerial work vehicle 1.

Next, the safety device will be described with reference to FIG. The safety device includes an extension length detector 11, a turning angle detector 12, an undulation angle detector 13, a calculator 14, and a turning restricting device 15.

The telescopic length detector 11 detects the telescopic length of the boom 5, and the turning angle detector 12 and the undulation angle detector 13 detect the turning angle and the undulating angle of the boom 5 with respect to the vehicle body 2, respectively.

The computing unit 14 is composed of a regulation area setting means 15, a selection means 16 and a control means 17, and calculates the state (position) of the boom 5 based on the state (position) of the boom 5 detected by the detectors 11 to 13. It is determined whether or not to restrict the turning operation, and if so, a restriction signal is output to the turning restricting device 15. The turning control device 15 is configured by a turning control valve or the like that shuts off the supply of pressure oil to driving means such as a hydraulic motor that turns the swivel 4 and controls the turning motion of the boom 5.

Here, the arithmetic unit 14 will be described in detail with reference to FIGS. First, the regulation area setting means 16
Stores two types of turning control areas of the boom 5 in advance. This is a first turning restriction region (a region from θ2 to θ2 ′ on the opposite side across the cab) from the turning region where the boom 5 and the cab 3 interfere with each other due to the turning of the boom 5.
And a second turning restriction area (θ3 on the opposite side of the driving cab from θ3), which is a turning area where the worktable 6 and the cab 3 interfere.
3 ').

Next, the selection means 17 determines that the extension and contraction length of the boom 5 detected by the extension and contraction length detector 11 interferes with the worktable 6 and the cab 3 no matter what the swing angle. If the length is not less than the length (L1), the first turning restriction area stored in the restriction area setting means 15 is selected, and if the extension length of the boom 5 is less than that, the restriction area is selected. The second turning restriction area stored in the setting means 15 is selected.

The control means 17 controls the selection means 1
6 and the turning angle detector 12 selected by the turning control area.
The rotation angle of the boom 5 detected by the above is compared, and when the boom 5 reaches the rotation restriction area, a restriction signal is output to the rotation restriction device 15 to restrict the rotation operation of the boom 5. Furthermore, when the boom 5 is equal to or greater than the upper-lower angle (θ1) of the driver's cab 3 by the hoisting angle detector 13, the above-described regulation of the turning operation is not performed. The control means 17 regulates the turning movement of the boom 5 in the direction approaching the cab 3, but allows the turning movement in the direction away from the cab 3.

By adopting such a safety device, the aerial work vehicle 1 restricts turning when the boom 5 and the worktable 6 are raised from an angle which does not interfere with the cab 3. In the case where the work table 6 falls down further, the turning of the boom 5 is restricted so as not to interfere even when the work table 6 is swung so as to be closest to the cab 3.
Alternatively, interference between the worktable 6 and the cab 3 can be prevented. In addition, if the boom 5 does not interfere with the cab 3 regardless of the swing position of the workbench 6, the boom 5 extends to a region closer to the cab 3 without interfering with the cab 3. You can turn.

In order to further expand the working range, FIG.
As described above, the swing angle detector 19 may be provided in the above safety device. The swing angle detector 19 detects the swing angle of the worktable 6 with respect to the boom 5. In this case, the selecting means 17 determines the swing angle detected by the swing angle detecting means 19 in the cab. If the direction is opposite to 3, the first turning restriction area is selected regardless of the amount of expansion and contraction of the boom 5. Thereby, the working range of the boom 5 is further expanded.

However, by merely restricting the turning movement of the boom 5 as described above, the boom 5 or the work table 6 and the cab 3 interfere with each other due to the swinging operation of the work table 6, the reduction operation of the boom 5, and the falling down operation. In some cases. Therefore, as shown in FIG. 3, by providing the safety device with the swing control device 20, the swing control device 21, the reduction control device 21 and the fall control device 22 in addition to the turning control device 15, the interference between the worktable 6 and the cab 3 is completely prevented. Is prevented.

The swing control device 20 controls the swing operation of the worktable 6 based on a control signal from the control means 18. When the swing control device 20 is provided, the control means 18 determines that the boom 5 is swinging to the position opposite to the cab 3 with respect to the axis of the boom 5 in the second turning control region. Restricts the worktable 6 from swinging in the direction of the cab 3 beyond the axis of the boom, and the worktable 6 swings in the direction on the same side as the cab 3 from the axis of the boom. In this case, the worktable 6 is restricted from swinging further in the direction of the cab 3.

The reduction control device 21 controls the reduction operation of the boom 5 in accordance with a control signal from the control means 18. When the reduction control device 20 is provided, the control means 18 controls the reduction operation of the boom 5 below the predetermined value when the boom 5 is in the first turning restriction area, In the case of the turning restriction region, the further reduction operation of the boom 5 is restricted.

The lodging control device 22 controls the operation of the boom 5 in response to a control signal from the control means 18. When the boom 5 is within the first turning restriction area, the control means 18 provided with the up-and-down operating device 22 determines that the boom 5 is lower than the upper end of the cab 3 by a predetermined value higher than the up-and-down angle (θ1). When the boom 5 is in the second turning restriction area and the work table 6 is swinging in the direction on the same side as the cab 3 from the axis of the boom 5, The lowering operation is restricted downward beyond the undulation angle (θ1) higher than the upper end of the cab 3 by a predetermined value. These regulating devices 20 to 22
Is provided, it is possible to prevent not only the interference due to the turning movement of the boom 5 but also the interference with the operator's cab 3 due to the swinging operation of the worktable 6 and the reduction operation and the falling down operation of the boom 5.

In the above embodiment, the case where two turning control regions are provided has been described, but three or more turning control regions may be provided. In this case, not only is the swing position of the worktable 6 determined on the same side or the opposite side than the cab 3 with respect to the axis of the boom 5, two or more swing angles are set to correspond to the turning restriction area. By controlling, it is possible to more finely widen the working range.

[0024]

As described above, if the safety device of the present invention is used, the boom and the workbench do not interfere with the cab, so that the operator can operate the boom without worrying about the interference. Boom operation becomes easy. In addition, since the position of the boom and workbench and the length of the boom are detected and regulated more finely, the boom can be operated in a wider range without impairing the interference prevention function compared to conventional safety devices. This makes it possible to use a work vehicle such as an aerial work vehicle more easily.

[Brief description of the drawings]

FIG. 1 is a block diagram of a safety device according to the present invention.

FIG. 2 is a block diagram of a safety device according to the present invention to which a swing angle detector is added.

FIG. 3 is a block diagram of a safety device according to the present invention to which a swing restriction device, a reduction restriction device, and a lodging restriction device are added.

FIG. 4 is a side view of an aerial work vehicle equipped with the safety device.

FIG. 5 is a plan view of an aerial work vehicle provided with the safety device and a conceptual diagram showing a boom restriction range.

[Explanation of symbols]

Reference Signs List 3 cab 16 regulation area setting means 5 boom 17 selection means 6 work table 18 control means 11 extension amount detector 19 swing angle detector 12 turning angle detector 20 swing regulation device 13 undulation angle detector 21 reduction regulation device 14 Arithmetic unit 22 Fall regulation device 15 Turn regulation device

Claims (4)

[Claims] 1. A work vehicle having a driver's cab at a front portion of a vehicle body, a boom capable of swiveling, raising and lowering and telescopic at a rear portion thereof, and a worktable capable of swinging horizontally at the tip of the boom. In the device, a telescopic length detecting means for detecting a telescopic length of the boom, a turning angle detecting means for detecting a turning angle of the boom, a raising and lowering angle detecting means for detecting a raising and lowering angle of the boom, When the expansion and contraction length of the boom is equal to or more than a predetermined amount that does not interfere with the operation table and the cab, the boom and the cab are turned by turning the boom when the undulation angle is equal to or less than the upper end of the cab. Is set as a first turning restriction area, and when the length of expansion and contraction of the boom is equal to or less than the predetermined amount at which the worktable and the cab interfere with each other, the work is performed by turning the boom. Table and driver's cab A restricting area setting means for setting a turning area in which interference occurs with a second turning restricting area; a first turning restricting area set in the restricting area setting means by a signal from the expansion / contraction length detecting means; Selecting means for selecting one of the turning restricted areas according to the length of expansion and contraction of the boom; and a signal from the selecting means, the up-and-down angle detecting means and the turning angle detecting means, wherein the boom is at or below the upper end of the cab. A safety device for a work vehicle, comprising: control means for restricting further rotation of the boom when the vehicle reaches the selected first or second turning restriction area at the undulation angle. 2. The safety of a work vehicle having a driver's cab at a front part of a vehicle body, a boom capable of turning, raising and lowering and expanding and contracting at a rear part thereof, and a worktable capable of swinging horizontally at the tip of the boom. In the apparatus, a telescopic length detecting means for detecting a telescopic length of the boom, a turning angle detecting means for detecting a turning angle of the boom, a hoisting angle detecting means for detecting a hoisting angle of the boom, and the workbench A swing angle detecting means for detecting a swing angle of the boom, when the boom has an undulation angle equal to or less than an upper end of the cab, the expansion and contraction length of the boom interferes with the worktable and the cab. If not more than a predetermined amount, and if the extension length of the boom is less than or equal to the predetermined amount, and the workbench is located on the opposite side of the driver's cab from the axis of the boom,
A swivel area where the boom and the cab interfere with each other due to the swing of the boom is set as a first swivel restriction area, and the extension and contraction length of the boom is equal to or less than the predetermined amount at which the worktable and the cab interfere with each other, And a restriction area setting means for setting, as the second rotation restriction area, a turning area in which the work table and the driver's cab interfere with each other when the boom is turned, when the work table is located closer to the cab than the axis of the boom. A first turning restriction area set in the restriction area setting means by a signal from the expansion / contraction length detection means and a swing angle detection means; Selecting means for selecting according to the swing angle of the worktable, and a signal from the selecting means, the hoisting angle detecting means, and the turning angle detecting means, the boom is moved at an hoisting angle below the upper end of the cab. And upon reaching a selected first or second turn restriction areas, safety device for a work vehicle, characterized in that a control means for regulating the pivotal movement of more booms. 3. The control means according to claim 1, wherein said control means restricts further turning movement of said boom when said turning position of said boom reaches a selected turning restriction area. When the selection is made, the boom is also restricted to a predetermined amount or less, and when the selection means selects the second turning restriction area, further reduction of the boom is also restricted. The safety device for a working vehicle according to claim 1 or 2. 4. The control means according to claim 1, wherein said control means restricts further pivoting movement of the boom when the turning position of the boom reaches the selected turning restriction area. And when the extension length of the boom is less than or equal to the predetermined amount, the work table is also restricted from swinging in the direction of the cab beyond the axis of the boom. A safety device for a working vehicle according to claim 3.