JP3178782B2 - Load detection device for aerial work vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a self-propelled vehicle body,
The present invention relates to an aerial work vehicle or the like configured with a boom that can freely move up and down and the like, and more particularly to a loaded load detection device that detects a loaded load on a work table provided at the end of the boom.

[0002]

2. Description of the Related Art In general, an aerial work vehicle is provided with a boom capable of turning, raising and lowering, expanding and contracting, etc., on a freely movable vehicle body. It is arranged and configured.

[0003] In the work using such an aerial work vehicle, tools, materials, and the like are mounted on a work table, and the operator himself gets on the work table. The work platform, which is loaded with workers and tools, materials, etc., is moved to a high position by raising and extending the boom. In the direction, a moment for turning the vehicle body (hereinafter, referred to as “turning moment”) acts. This overturning moment increases in accordance with an increase in the load on the workbench, extension of the boom, and the like. Preferably, the boom operation is regulated according to the load on the work table so that the stability of the vehicle body is not threatened by the overturning moment that changes according to the boom operation. If the boom operation range is set in accordance with the load, the work range of the worktable with respect to the vehicle body can be safely and widely secured.

For this reason, conventionally, as a detecting device for detecting the load loaded on the worktable, a bracket is provided at the end of the boom so as to receive substantially the entire bottom surface of the worktable, and load cells are arranged at four corners of the bracket. There is a mounted load detecting device provided with a workbench on these load cells. In this load detection device, the actual load is obtained by adding the detection values obtained from the plurality of load cells by a computing unit.

[0005]

By the way, in such a manner that the load cells are respectively arranged at the four corners of the bottom surface of the work table, in order to detect an accurate load, the load cell is adjusted according to the width of the bottom surface of the work table. There is a problem that the mounting interval of the load cells must be widened, and the bracket itself for supporting each load cell on the boom side also becomes large. It is not preferable that the bracket becomes large and the boom tip becomes heavy because the beam strength of the boom and the stability of the vehicle body are reduced. Also, it is not preferable in terms of production cost that the bracket must be formed large in accordance with the size of the bottom of the worktable.

Further, in this conventional load detecting device, since the load cell and the bracket are arranged below the bottom of the work table, it is difficult for an operator who gets on the work table to have a view below the work table. Also, when attempting to work with the workbench placed between beams, the height of the workbench and the bracket attached to the lower surface of the workbench may hinder the workbench placement operation There is also. Therefore, it may not be possible to arrange a worktable between the beams, and the workability of working at heights in a narrow work environment has been impaired.

Further, in such a configuration, since the worktable is supported only by the bottom surface, there is a problem that stability of the worktable against lateral vibration is low and riding comfort of the worktable is impaired. SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and is simple to attach to a workbench, excellent in operability and stability of the workbench, and high in height to accurately detect a load loaded on the workbench. It is an object of the present invention to provide a load detection device for a work vehicle.

[0008]

In order to achieve the above-mentioned object, a loaded load detecting device for an aerial work vehicle according to the present invention comprises: a boom-side bracket disposed at a tip of a boom of an aerial work vehicle; A workbench on which a worker rides, a workbench-side bracket provided on the side of the workbench, and a workbench-side bracket and a boom-side bracket provided between the workbench-side bracket and the boom-side bracket. A plurality of connecting means for connecting the workbench-side bracket and the boom-side bracket at a position having an interval in a direction connecting the plurality of connecting means, and a load detecting means for detecting a vertical load at each of the arrangement positions of the plurality of connecting means. And load calculating means for calculating the actual load from the value detected by the load detecting means. Further, it is more preferable that at least three connecting means are provided, and the connecting means are provided with an interval also in a direction perpendicular to a direction connecting the position of the boom and the position of the worktable.

[0009]

According to the load detecting device for an aerial work vehicle of the present invention, the load applied to the work table is transmitted from the work table side bracket provided on the side of the work table to the boom side via a plurality of connecting means. Supported by brackets. Since all loads on the workbench are received by the plurality of connecting means, the load in the vertical direction at each position of the connecting means is detected by the load detecting means, and all the detected values are calculated by the load calculating means, whereby the actual load is calculated. Load is determined accurately.

The vertical load (vertical reaction force) acting on these connecting means increases and decreases when the position of the loaded load is changed on the work table. Does not change, so
The load value calculated as described above is not affected by the change in the position of the load. That is, the effect of the movement of the worker or the movement of the tool, the material, or the like in the work table does not appear in the calculated value, and the accurate loading load of the work table can always be detected.

As described above, the load detection device according to the present invention comprises:
Since the detected load value is not affected by the change in the position of the load and the detected value detected by the load detecting means is calculated by the load calculating means to obtain the load value, the detection accuracy of the load can be detected. Depends only on the detection accuracy of the load detection means and the calculation accuracy of the load calculation means. As the load detecting means, extremely high-precision ones such as an electromagnetic sensor and an optical sensor can be used, and as the calculating means, a microcomputer or the like can be used. You.

Further, since the workbench-side bracket provided on the side surface of the workbench is supported by the boom-side bracket provided at the end of the boom, the conventional case where the workbench bottom is supported by the bracket is different from that of the conventional case. Differently, even when using a large work table, it is not necessary to make the bracket itself large. Since the bracket is compact, the increase in the bracket weights the boom tip and reduces the boom strength and the stability of the car body as before, eliminating the possibility of the stability of the boom strength and the stability of the car body. The nature increases.
Further, since the load detection device thus configured can be adopted for various types of aerial work vehicles regardless of the size of the work table, the load detection device can be standardized, and production costs can be reduced. You.

Furthermore, since the brackets are provided on the side surfaces of the worktable as compared with the conventional case where the brackets are provided on the bottom surface of the worktable, it is easy to suppress the lateral swing of the worktable, and the riding comfort of the worktable is improved. improves. In addition, the field of view below the worktable is wide, and worktable operation such as inserting the worktable between beams to perform work can be easily performed. For this reason, workability at a high place in a narrow work environment is improved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 3 shows an aerial work vehicle 10 according to the present invention. This aerial work vehicle 10 is generally
It is composed of a body part and a boom part. The body part is mainly
Self-propelled vehicle body 11 having driving wheels, and vehicle body 11
It comprises a boom drive source such as a hydraulic pump (not shown) disposed therein, and a boom operation control section such as a controller (not shown) mounted on the vehicle body 11. Also, the vehicle body 11
Outrigger jacks 19 are provided on the front, rear, left and right sides of the vehicle to stably support the vehicle body 11 during work by extending and grounding.

A turntable 12 is provided on the vehicle body 11, and the turntable 12 is rotatable by a hydraulic motor (not shown) provided inside the vehicle body 11. A boom 13 is pivotally supported at the upper end of the swivel base 12 by a support shaft 12 a, and an up-and-down cylinder 15 is fixed to the boom 13 from the swivel base 12. The boom 13 can be freely raised and lowered by the raising and lowering cylinder 15. The boom 13 includes a plurality of boom members 13a, 13b, and 13c, which are telescopically assembled, and can be freely extended and retracted by a telescopic cylinder (not shown) provided in the boom.

A vertical post 18 is pivotally supported at the distal end of the distal boom member 13c, and a boom-side bracket 22 is attached to the vertical post 18. The worktable 21 is attached to the boom-side bracket 22 via a worktable-side bracket 23. The vertical post 18 is connected to the leveling cylinder 14a regardless of the up / down state of the boom 13.
And 14b keep it always perpendicular to the ground. For this reason, the bottom surface of the worktable 21 supported by the vertical post 18 is always kept parallel to the ground so that the worker can work comfortably.

FIGS. 1 and 2 show a load detecting device according to the present invention.
This will be described with reference to FIG. The boom-side bracket 22 and the workbench-side bracket 23 are brackets formed in a “T” shape when viewed from above. The boom-side bracket 22
It is attached to the vertical post 18 so as to be horizontally pivotable by a hydraulic motor (not shown).

A worktable-side bracket 23 is disposed above the boom-side bracket 22, and the worktable-side bracket 2
3, a "T" head portion 23a is fixed to the side surface of the worktable 21, and the foot portion 23b extends horizontally with the foot portion 23b protruding toward the boom 13. Bosses are formed at three ends of the workbench-side bracket 23 downward.

On each lower surface of these bosses, as a cushioning material,
Mounting rubbers 24a, 24b and 24 having a cylindrical shape
c are disposed with their cylindrical axes oriented in the vertical direction, and on the lower surfaces of these mounting rubbers 24a, 24b and 24c, load cells 25a, 25b and 25c each having a rectangular parallelepiped shape are provided.
Is stopped by a bolt (not shown).
The other end of each of the load cells 25a, 25b and 25c is
Each of the three end portions of the boom-side bracket 22 disposed below the workbench-side bracket 23 is clamped and bolted (not shown) so as to overlap the worktable-side bracket 23. As described above, since the boom-side bracket 22 is horizontally rotatable with respect to the vertical post 18, the workbench 21 disposed on the boom-side bracket 22 via the workbench-side bracket 23 as described above is mounted on the vertical post 18. 18 can be swiveled horizontally.

As described above, the workbench-side bracket 23 and the boom-side bracket 22 are connected via only three mount rubbers 24 and three load cells 25.
In the present embodiment, the load cell 25 doubles as the connecting means and the load detecting means described in the claims. These load cells 25a, 25b and 25c serve as connecting means at three points on the horizontal
The load detection is performed while supporting the work table 21 via 3.
Such support at three horizontal positions is preferable from the viewpoint of securing the stability of the worktable 21 and also of compactly configuring the boom-side bracket 22 and the worktable-side bracket 23.

These load cells 25a, 25b and 25
c is detected by the boom side bracket 22.
It is calculated by a load calculating means (not shown) in a control box (not shown) provided in the vicinity,
1 is required. As described above, the load on the work table is reduced by three work table side brackets 23 disposed on the side surface of the work table 21 and three boom side brackets 22 disposed on the boom tip. Load cell 25a,
Since the detection is made by 25b and 25c, the size of both brackets 22 and 23 is determined regardless of the size of the worktable bottom surface.

Now, when the worker gets on the work table 21 and places work tools, materials, and the like, as shown in FIG. 1, the work table load and the vertical load W, which is the total load of the tools, are applied. It acts on the table 21. When the vertical load W acts on the workbench 21, three load cells 25 serving as a connecting means between the workbench-side bracket 23 and the boom-side bracket 22.
A reaction force corresponding to this vertical load acts on a, 25b and 25c. The reaction forces R1 and R3 acting on the two load cells 25b and 25c near the worktable, and the reaction force R2 acting on one load cell 25a remote from the worktable,
Acts in opposite directions. These reaction forces R1, R2
And the magnitude of R3 change in accordance with the change in the position of the vertical load W. If the distance L1 from the two load cells 25b and 25c near the worktable to the vertical load W increases,
That is, if the vertical load W moves away from the vertical post 18 in the work table 21, the reaction forces R1, R2, and R3 also increase. This is because the moment acting on the load cells 25a, 25b and 25c changes according to the change in the position of the vertical load W.

However, in the vertical balancing, the vertical load W and the reaction forces R1, R2 and R3 are:
The relationship of the following equation (1) always holds.

W + R2 = R1 + R3 (1)

Therefore, the vertical load W can be calculated from the reaction forces R1, R2 and R3 as shown in the following equation (2).

W = R1 + R3-R2 (2)

The vertical load W is obtained by calculating the sum of the reaction force R1 and the reaction force R3 and the difference between the sum and the reaction force R2, regardless of the change in the load position and the distance L1, that is, the momentum of the moment. Detectable with no effect.

From these detected values R1, R2 and R3 detected by the load cells 25a, 25b and 25c,
The calculation means performs the calculation of the above equation (2) to obtain the vertical load W. Since the vertical load W includes the weights of the work table 21, the work table side bracket 23, the mount rubbers 24a, 24b, and 24c, by subtracting these weights, the work table 21 can be purely loaded. Is obtained.

As described above, the load cells 25a, 25
Since the three load cells are horizontally arranged so that only the load of the vertical component acts on b and 25c, and the mounting rubbers 24a, 24b and 24c have a cushioning function, The load detecting device can accurately detect a loaded load without being affected by any change in the position of a moving object or a change in the location of a material, a tool, or the like. Each reaction force R1, R2, and R3 with respect to the load W is determined by load cells 25a, 25b, and 25 serving as load detection means.
Since it directly acts on c, the accuracy of load detection depends only on the resolution (detection accuracy) of the load cells 25a, 25b and 25c and the calculation accuracy of the load calculation means. Since load detection and calculation processing can be performed in an electronic circuit, high-precision load detection is possible.

The present invention is not limited to the above embodiment, and it is most preferable that the work table 21 is received by three load cells 25a, 25b and 25c. Arithmetic processing is possible. The boom-side bracket 22 and the workbench-side bracket 2
More preferably, 3 is formed with a cover for protecting the mount rubbers 24a, 24b and 24c and the load cells 25a, 25b and 25c. Obviously, further improvements, improvements, modifications and the like can be made within the scope of the claims of the present invention.

[0031]

As described above, according to the apparatus for detecting a load on an aerial work platform according to the present invention, the work table is provided with a plurality of connecting means from the work table side bracket disposed on the side surface of the work table. Supported on the boom side bracket. The load on the workbench is obtained by detecting the vertical load at each of the positions at which the plurality of connecting means are disposed by the load detecting means and calculating the load by the load calculating means.

Each vertical reaction force acting upward or downward on the plurality of connecting means increases or decreases in accordance with a change in the moment resulting from a change in the load position. The sum is always constant and does not change. Therefore, the calculated loading load value is not affected by the moment, and does not appear even if the worker moves or the tool, the material, or the like is moved in the workbench. Therefore, the load on the worktable can be accurately detected.

As described above, the load detection device of the present invention
Since the detected load value is not affected by the change in the position of the load and the detected value detected by the load detecting means is calculated by the load calculating means to obtain the load value, the detection accuracy of the load can be detected. Depends only on the detection accuracy of the load detecting means and the calculation accuracy of the load calculating means. As the load detecting means, extremely high-precision ones such as an electromagnetic sensor and an optical sensor can be used, and a microcomputer or the like can be used as the calculating means. can get.

Also, the workbench-side bracket provided on the side surface of the workbench is provided on the boom-side bracket provided at the end of the boom via a plurality of connecting means. The size of the bracket can be determined without being affected. For this reason, unlike the conventional case in which the bottom surface of the worktable is supported by the bracket, there is no need to increase the size of the bracket itself in order to provide a large worktable. Therefore, the load detection device of the present invention
Since it can be used for various types of aerial work vehicles regardless of the size of the work table, standardization is possible and production costs are reduced. Further, unlike the related art, the number of brackets is not excessively increased, the boom tip is made heavy, and the boom strength and the stability of the vehicle body are not reduced.

As described above, since the bracket is provided on the side surface of the worktable, it is easier to suppress the lateral run-out than the conventional case where the bracket is provided on the bottom surface of the worktable, and the stability of the worktable is improved. improves. Also, the view below the workbench is wide,
Workbench operations such as placing a workbench between beams to perform work can be performed easily. For this reason, workability at a high place in a narrow work environment is improved.

[Brief description of the drawings]

FIG. 1 is a side view of a device for detecting a loaded load of an aerial work vehicle.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is an overall side view of the aerial work vehicle according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Aerial work vehicle 11 Body 12 Turning table 13 Boom 15 Undulating cylinder 18 Vertical post 21 Work table 22 Boom side bracket 23 Work table side bracket 24 Mounting rubber 25 Load cell

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B66F 9/24

Claims (2)

(57) [Claims] 1. A boom-side bracket disposed at a tip of a boom of an aerial work vehicle, a work table on which an operator rides, a work table-side bracket disposed on a side surface of the work table, and The workbench-side bracket and the boom-side bracket are disposed between a base-side bracket and the boom-side bracket, and at a position having an interval in a direction connecting the position of the boom and the position of the workbench. A plurality of connecting means connected to each other and supporting the work table by the boom-side bracket via the work table-side bracket; and a load detecting means for detecting a vertical load at each of the arrangement positions of the plurality of connecting means. A load calculating device for an aerial work vehicle, the load calculating device comprising: a load calculating unit configured to calculate an actual load from a value detected by the load detecting unit. 2. The apparatus according to claim 1, wherein at least three connecting means are provided, and the connecting means are provided at intervals also in a direction perpendicular to a direction connecting the position of the boom and the position of the worktable. The loaded load detecting device for an aerial work vehicle according to claim 1.