JPH08175800A - Load detection device for work equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to accurately detect the load on the workbench, and especially when the workbench can freely rotate horizontally, it is possible to always detect the load accurately regardless of the rotation. Obtain a load detection device. [Structure] The workbench 21 is attached to a workbench side bracket 22, and the workbench side bracket 22 is a vertical post side bracket 25 attached to a vertical post member 23.
It is configured to be able to move vertically up and down. A load cell 31 is arranged between the workbench side bracket 22 and the vertical post side bracket 25, and detects a load acting on the vertical post side bracket 25 from the workbench side bracket 22. As a result, the load on the workbench 21 is lowered by the workbench side bracket 22 which can be vertically moved up and down with respect to the vertical post side bracket 25.
1, so that the worktable 21 can be continuously and accurately detected.
The load of can be detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work apparatus having a work table attached to a vertical post member, such as a work table attached to the tip of a boom of an aerial work vehicle. At work table load (weight)
The present invention relates to a load detection device for detecting.

[0002]

2. Description of the Related Art An aerial work vehicle is configured to have a worktable on which a worker rides at the tip of a boom that can be raised, contracted, turned, etc., regardless of whether the boom is raised or lowered. A vertical post is mounted so as to be always vertical, and a work table is mounted on the vertical post so as to be horizontally pivotable. In such an aerial work vehicle, since the moment in the falling direction applied to the vehicle body changes depending on the boom undulation, extension / contraction, and turning operation, the boom undulation, extension / contraction, and turning operation such that this moment exceeds a predetermined value. A work range control device is installed to control the work so that safe work can be performed.

[0003] The conventional work range restricting device is designed so that the moment applied to the vehicle body does not exceed a predetermined value. ) Is set in advance, and the operation of the boom is restricted so that the actual posture position of the boom exceeds the allowable posture position range when the operation of the boom is performed. However, the load on the worktable varies, and the moment applied to the vehicle body also varies according to the variation. Therefore, in the conventional work range regulating device, the boom operation is appropriately regulated by detecting the load of the workbench acting on the vertical post.

[0004]

As a load detecting means for a workbench, the workbench is supported on a vertical post through a spring, and the displacement amount of this spring is detected by using a limit switch or a proximity switch. Is configured to detect the load of the work table. In the load detecting means configured as described above, since the detection is performed by the mechanical switch, the error at the time of detection is large, and the changing load cannot be continuously detected, and only the stepwise load is detected. There is a problem that you can not.

Also, as shown in FIG.
It is also conceivable to dispose the load cell 71 between the above and the support portion 62 of the workbench so as to detect the load of the workbench 61 accurately and continuously. However, normally, the workbench 61
For the turning operation, the motor having the worm gear 66 is arranged on the side of the workbench 61, and the worm gear 66 is connected to the vertical post 6
The worm wheel 64 disposed on the No. 3 meshes with the worm wheel 64, and the motor is rotated to rotate the workbench 61 with respect to the vertical post 63. Therefore, when the load cell 71 is arranged as described above, the motor is driven in the direction of lifting the workbench 61 (reducing the detected load) by the reaction force when the workbench rotates (when the motor is rotationally driven). Since a force is applied or the driving force of the motor is applied in a direction in which the workbench 61 is pressed (the detected load increases), there is a problem that the load on the workbench 61 cannot be accurately detected.

Further, the load center (center of gravity) G of the workbench 61
Is eccentric from the turning center O, the load cell 71 receives not only the weight itself of the workbench 61 but also a moment having this eccentric amount as a moment arm, and as shown in FIG. 7, the load distribution Pr of the load cell is uniform. Does not mean Therefore, the load cell 61 is fixed to the vertical post 63 side, and the strain gauge 71a in the load cell 71 is fixed.
When the attachment position of is eccentric with respect to the center O, there is also a problem that the detected load changes depending on the turning direction of the workbench 61.

The present invention has been made in view of the above problems, and an object thereof is to provide a load detecting device capable of accurately detecting a vertical load (weight) of a workbench, and in particular, the workbench horizontally swings. It is an object of the present invention to provide a load detecting device which can always accurately detect a load when it is free, regardless of its turning.

[0008]

In order to achieve such an object, according to the present invention, when detecting the load of the workbench acting on the vertical post member, the workbench is attached to the vertical post member by a bracket on the vertical post side. Also, it will be done via the workbench side bracket. A vertical post side bracket is attached to the vertical post member, and a work table side bracket is attached to the work table. A guide rail extending in the vertical direction is provided on one of the workbench side bracket and the vertical post side bracket, and the other bracket is movably disposed along the guide rail and An elevating member is provided for moving the work table side bracket up and down. Further, a load cell is arranged between the workbench side bracket and the vertical post side bracket to detect the vertical load acting on the vertical post side bracket from the workbench side bracket.

[0009]

According to the load detecting device of the working device constructed as described above, the deflection amount of the load cell increases as the load of the working table increases. Since it can be raised and lowered, the load on the workbench is accurately detected by the load cell when the workbench side bracket is lowered. Since the workbench side bracket is movable only in the vertical direction with respect to the vertical post side bracket by the guide rail and the elevating member, the load cell is not subjected to a twisting force or the like, and only the vertical load of the workbench side bracket is applied. To do. Accordingly, even if the load on the workbench changes, the load on the workbench (vertical load) can be continuously and accurately detected. In this case, in order to detect the load more accurately, the load cell should be installed in the center of the vertical post side bracket and the workbench side bracket, and the workbench side bracket should be swingable with respect to the load cell. Is desirable.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. An example of an aerial work vehicle having a load detection device according to the present invention is shown in FIG. This aerial work vehicle 10 has a swivel base 12 that can swivel on a vehicle body 11,
A telescopic boom 13 is attached to the swivel base 12 so as to be up and down. The telescopic boom 13 is composed of a telescopically (nestedly) telescopically adjustable base boom 13c, an intermediate boom 13b, and a tip boom 13a. The base boom 13c is pivotally supported by a swivel base 12 via a support shaft so that the telescopic boom 13 can be raised and lowered. Has become. The telescopic boom 13 is telescopically operated by a telescopic cylinder (not shown) provided inside,
The hoisting and lowering operation is performed by a hoisting cylinder 15 arranged between the swivel base 12 and the base end boom 3c. Outriggers 16 are attached to the front, rear, left, and right of the vehicle body 11 at four positions to extend and support the vehicle body 11 during work.

A swiveling workbench device (working device) 20 is provided at the tip of the tip boom 13a. The swiveling workbench device 20 is provided with a vertical post 23 that always maintains a vertical state.
A vertical post-side bracket 25 rotatably disposed on the vertical post 23; a workbench side bracket 22 vertically movably mounted on the vertical post-side bracket 25; and a workbench side bracket 22. And a workbench 21 attached to the.

The swivel workbench apparatus 20 will now be described with reference to FIGS. A support member 23a is attached to the tip of the tip boom 13a so as to be vertically swingable, and the support member 23a is fixed to the vertical post 23. The vertical post 23 has a vertical post side bracket 2
5, the arm member 29 attached to the bearing 5 is a bearing 28,
It is rotatably attached via 28. As a result, the vertical post side bracket 25 can be swung up and down and horizontally swung around the vertical post 23.

The swinging operation of the support member 23a is performed by the expansion / contraction operation of the leveling cylinder 16 arranged on the tip boom 13a. This operation control is performed by a leveling mechanism (not shown) to adjust the hoisting angle of the expansion / contraction boom 13. Regardless of how the vertical post 23 is controlled, the vertical post 23 is always in the vertical state. The swing operation of the arm member 29 is performed by meshing with the worm wheel 24 fixed to the vertical post 23 and rotating the worm gear 27 attached to the arm member 29. The rotation drive of the worm gear 27 is performed by the turning drive motor 26 also attached to the arm member 29.

A vertical post bracket 25 is provided at the end of the arm member 29 opposite to the pivotal support of the vertical post 23.
Is attached. This vertical post side bracket 2
5 is formed in a rectangular shape, and rollers that rotate in roller guides 122 and 222 provided on a workbench side bracket 22, which will be described in detail later, are provided at four positions, up, down, left and right. This roller is attached to roller support plates 45a, 45b, 45c and 45d which are attached to the upper and lower positions on both side surfaces of the vertical post side bracket 25. Each of the roller support plates 45a to 45d is
Front-rear regulation rollers 41a, 41b, 42a, 42b whose rotation axes extend in the left-right direction (width direction of the work table 21), and
Left and right regulating rollers 43a, 43b, 44 whose rotary shaft extends in the front-rear direction (direction from the vertical post 23 to the workbench 21).
a and 44b are rotatably arranged.

A load cell mounting member 35 is fixed to an intermediate portion of the vertical post side bracket 25 in the left-right direction. A load cell 31 is attached to the upper surface of the load cell attachment member 35 so as to extend in the front-rear direction. The tip end side (workbench 21 side) of the load cell 31 is disposed so as to project from the load cell attachment member 35, and the connecting member 32 is pivotally supported at the tip end thereof by a pivot pin 32a so as to be swingable in the front-rear direction. ing.

The connecting member 32 is composed of a base portion 32b pivotally supported by the load cell 31, and a rubber bush receiver 32c disposed on the upper portion of the base portion 32b so as to be swingable in the left-right direction. . Two rubber bushes (anti-vibration rubber) 33, 33 are attached to the upper surface of the rubber bush receiver 32c. A workbench side bracket support member 34 fixed to the workbench side bracket 22 is attached to the upper surfaces of the rubber bushes 33, 33.

On the left and right side surfaces of the workbench side bracket 22,
Roller guides (guide rails) 122 and 222, which are formed in a U shape having an opening on the outside and extend in the vertical direction, are provided. The left and right regulating rollers (elevating members) 43a, 43b, 44a, 44b attached to the vertical post side bracket 25 come into contact with the inner side surfaces 122a, 222a of the roller guides 122, 222.
Further, the front and rear regulating rollers 42a and 42b on the upper side come into contact with the surfaces 122b and 222b on the vertical post side, and the lower front and rear regulating rollers 41a and 41b on the surfaces 122c and 222c on the workbench side. It is configured to abut and contact. Accordingly, the workbench side bracket 22 and the vertical post side bracket 25 are configured to be vertically movable without shifting in the front-rear direction and the left-right direction.

The workbench 21 on which the operator can ride is attached to the workbench side bracket 22 constructed as described above. As a result, the load on the workbench 21 is detected by the load cell 31 arranged between the workbench side bracket 22 and the vertical post side bracket 25. When a load is applied to the workbench 21, the portion of the load cell 31 protruding from the load cell mounting member 35 bends downward,
This amount of deflection is detected as the load on the workbench 21. At this time, the workbench side bracket 22 vertically descends with respect to the vertical post side bracket 25 by the amount of the deflection,
Since the lowering operation is smoothly performed by each of the rollers, the detected load is not affected. Further, since the connecting member 32 is swingable in the front-rear, left-right direction with respect to the load cell 31, each roller guide 122, etc. and each roller 43a.
Even when the workbench 21 swings in the front-rear, left-right directions due to a slight gap between the workbench 21 and the like, the workbench 21 can be smoothly moved in the vertical direction.

As the load on the workbench 21 increases, the amount of deflection of the load cell 31 also increases.
If the amount of deflection is excessive, the load cell 31 will be adversely affected. Therefore, in the above embodiment, a stopper is provided to stop the lowering operation of the workbench side bracket 22 when the loaded load reaches the maximum allowable load,
The load cell 31 is intended to be protected. The stopper includes stopper plates 46 a and 46 b fixed to the workbench side bracket 22 and the stopper plate 46.
stopper bolts 47a, 47b screwed to a, 46b
And the bolt receivers 48a and 48b fixed to the vertical post-side bracket 25, and the stopper bolts 47a and 48b when the workbench-side bracket 22 descends.
47b and the bolt receivers 48a, 48b are in contact with each other, and further lowering of the workbench side bracket 22 is restricted. The vibration of the workbench 21 is caused by the rubber bush 3.
Since it is absorbed by 3, 33, the load cell 31 is not adversely affected.

According to the load detecting device of the workbench constructed as described above, not only when the workbench 21 is stopped in front of the boom 13 with respect to the vertical post 23, but the workbench 21 is moved to the left and right. The vertical load on the workbench 21 can always be detected accurately even when the vehicle is turned or during the turning operation.

Next, referring to FIG. 5, the load cell 31
The operation control based on the load detected by will be described. The detection signal detected by the load cell 31 is transmitted to a load cell amplifier 54 provided on a workbench (in a boom operating device (not shown) provided on the workbench, etc.) 21, and the load cell amplifier 54 also has the same workbench 21. It is transmitted as a display signal to the display device 53 disposed in the vehicle and is also transmitted as a control signal to the controller 51 disposed in the vehicle body 11 via the telescopic boom 13. Since the loading load of the workbench 21 is displayed on the display device 53, the operator on the workbench 21 can directly grasp the load of the workbench 21 by visual observation.

Further, the controller 51 uses the load cell 3
In addition to the signal from 1, the expansion / contraction amount of the telescopic boom 13, the hoisting angle,
The operation of the telescopic boom 13 is restricted (moment limiter control) based on the turning angle. Then, when the load on the workbench 21 reaches the allowable load or the moment limiter is regulated, a voice alarm is issued by the speakers 52 and 55 provided on the workbench 21 and the vehicle body 11 to warn the operator. Evoke. As a result, the operation control can be performed with high accuracy, and the workability can be improved.

In the above-described embodiment, the work platform mounted on the tip of the boom of the aerial work vehicle so as to be rotatable is explained as an example, but the present invention is not limited to this, and other swing working devices and booms are used. Of course, it can also be applied to worktables that do not turn. Further, in the above-mentioned embodiment, the roller which is rotatable with respect to the guide rail (roller guide) is used as the elevating member, but it slides with respect to the guide rail formed of synthetic resin or the like having a low friction coefficient. A sliding member may be used.

[0024]

As described above, according to the present invention,
The workbench is attached to the workbench side bracket, and the workbench side bracket is configured to be vertically movable up and down with respect to the vertical post side bracket attached to the vertical post member. A load cell is arranged between the workbench side bracket and the vertical post side bracket to detect the vertical load acting on the vertical post side bracket from the workbench side bracket. As a result, even if the deflection of the load cell increases as the load on the workbench increases, the workbench side bracket can move up and down with respect to the vertical post side bracket, and the workbench side bracket moves vertically with respect to the load cell. The vertical load on the workbench is accurately detected by the load cell as the workbench-side bracket descends because it moves only to. Therefore, even if the load on the workbench changes, the load on the workbench can be continuously and accurately detected, and the moment limiter control and the like performed based on the detected load on the workbench can be accurately performed. Therefore, a worker or the like who has boarded the work table can accurately grasp the load on the work table.

[Brief description of drawings]

1 is a cross-sectional view taken along the line I-I in FIG. 3 of a work device having a load detection device according to the present invention.

FIG. 2 is a sectional view of the working device taken along line II-II in FIG.

FIG. 3 is a view of the work device as viewed in the direction of arrow III in FIG. 1.

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

FIG. 5 is a block diagram for performing operation control based on the detected load.

FIG. 6 is a side view of a workbench provided with a conventional load detection device.

FIG. 7 is an explanatory diagram showing a load distribution on the workbench.

[Explanation of symbols]

 10 High-altitude work vehicle 11 Vehicle body 12 Revolving platform 13 Telescopic boom 21,61 Work platform 22 Work platform side bracket 23,63 Vertical post 24,64 Worm wheel 25 Vertical post side bracket 26,66 Worm gear 31,71 Load cell

Claims (1)

[Claims] 1. A working device comprising a vertical post member and a workbench attached to the vertical post member,
A load detection device for a work device that detects a vertical load acting on the vertical post member from the workbench, wherein the vertical post-side bracket is disposed on the vertical post member, and the work attached to the workbench. A table-side bracket, a guide rail provided to extend vertically in one of the vertical post-side bracket and the workbench-side bracket, and a guide rail provided in the other of the vertical post-side bracket and the workbench-side bracket along the guide rail. And an elevating member for vertically moving the workbench side bracket with respect to the vertical post side bracket, and an elevating member disposed between the workbench side bracket and the vertical post side bracket. A load cell for detecting a vertical load applied from the work table side bracket to the vertical post side bracket, Load detecting device for a working device, characterized in that Ranaru.