JPH0967099A - Carrying load detecting device of vehicle for high lift work - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carrying load detecting device of a vehicle for high lift work, for detecting only a vertical component of the load on a workbench. SOLUTION: Upper and lower link members 22, 23 are pivotally supported to a bracket 16 and a boss 21a by a link shaft 24, and a horizontal parallel link mechanism is constituted. A load cell 25 is arranged on the upper surface of the U-shaped lower projecting part of the bracket 16 as a base part of the parallel link mechanism, and the lower surface of the boss 21a of the workbench as a movable part of the parallel link mechanism is received by the load cell 25. Since the effect of the moment from the workbench load is absorbed as tension and compressive force to the upper link members 22, 23, force to act on the load cell 25 is only the vertical load. Therefore, the accurate detection of the carrying load of the workbench can be performed by the load cell 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to an aerial work vehicle or the like in which a boom that can be freely actuated such as ups and downs is arranged, and particularly relates to a means for detecting a load on a workbench provided at the tip of the boom.

[0002]

2. Description of the Related Art Generally, an aerial work vehicle is provided with a boom which can be freely swung, raised and lowered, and extended and retracted on a freely movable vehicle body, and a worktable on which an operator can ride is provided at the tip of the boom. It is arranged.

In working with an aerial work vehicle, tools, materials and the like are placed on the workbench, and the worker himself also rides on the workbench. The work platform, which receives the load of the operator, tools, materials, etc., is moved to a higher position by raising and extending the boom, etc. A moment (hereinafter, referred to as "falling moment") that causes the vehicle body to fall in the direction in which it acts is applied. This overturning moment increases in accordance with an increase in the load on the workbench, an extension operation of the boom, and the like. In order to prevent the stability of the vehicle body from being threatened by the falling moment that changes according to the boom operation, the boom operation is restricted within a certain range in each state such as the load on the workbench and the grounding of the jack. A work range regulating device is known as a means.

In this work range regulating device, the regulation range may be set based on the maximum allowable load,
It is preferable that the payload is detected and a regulation range corresponding to the payload is set. If the work area corresponding to the load is set in accordance with the load, the work area of the workbench is widened. Conventionally, for this purpose, as a load detection means, a load cell is arranged between a vertical post provided at the tip of the boom and a mounting portion of a workbench pivotally supported on the vertical post so as to be horizontally rotatable. Has been done.

[0005]

By the way, in the load detection by the load cell thus arranged, a moment from the workbench with the vertical post as a fulcrum acts, and this moment is detected by the load cell. Since the influence appears, there is a problem that the load detection is difficult. Further, the magnitude of this moment increases or decreases according to the position change of the load in the workbench, which makes it more difficult to accurately detect the load.

Particularly, in an aerial work vehicle having a work table swinging mechanism with an articulated arm, not only is the arm pivotally supported by a vertical post rotatable but also the work table is present at the end of this arm. Since the can be swiveled, the distance between the vertical post and the work table constantly changes when the work table is moved horizontally. For this reason, it is very difficult to obtain an accurate load with the conventional load detection means using the load cell sandwiched between the vertical post and the workbench mounting portion. The present invention has been made in view of the above problems, and provides a load detection device for an aerial work vehicle that detects only the vertical component of the workbench load, excluding the influence of the moment due to the workbench load. Is intended.

[0007]

In order to achieve the above object, a load detecting device for an aerial work vehicle according to the present invention comprises a bracket arranged at the tip of a boom, a work table, and one end of the work table. Part is pivotally supported and extends substantially horizontally, and the other end part is pivotally supported by the bracket, and one end part is pivotally supported by the work table and the other end part is supported by the bracket. Is composed of a lower link member that is pivotally supported, and load detecting means that is arranged between the bracket and the workbench so as to receive a vertical load.

[0008]

An apparatus for detecting a load on an aerial work vehicle according to the present invention comprises a bracket, a workbench, and an upper link member extending horizontally.
A parallel link mechanism is constituted by the lower link member extending in parallel with this. With respect to the bracket as the base portion of the parallel link mechanism, the work table as the movable portion is movable in the vertical direction, and the movement in the vertical direction is received and blocked by the load detecting means. Therefore, only the horizontal pulling force to the upper link member, the horizontal compressive force to the lower link member, and the vertical compressive force to the load detecting means act from the workbench to the bracket. In this way, the influence of the moment due to the workbench load is removed, and only the vertical load acts on the load detecting means, so that the accurate load on the workbench can be detected.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an aerial work vehicle 10 according to the present invention. This aerial work vehicle 10 is roughly
It consists of a car body and a boom. The body part is mainly
Self-propelled vehicle body 11 having driving wheels, and this vehicle body 11
It comprises a boom drive source such as a hydraulic pump (not shown) disposed inside, and a boom operation control portion 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 of the vehicle to extend and ground to stably support the vehicle body 11 during work.

A swivel base 12 is disposed on the vehicle body 11, and the swivel base 12 is rotatable by a hydraulic motor (not shown) disposed inside the vehicle body 11. A boom 13 is pivotally supported on the upper end of the swivel base 12 by a support shaft 12a, and a hoisting cylinder 15 is attached to the boom 13 from the swivel base 12. With the hoisting cylinder 15, the boom 13
Can be lifted and lowered freely. Further, the boom 13 is formed by nesting a plurality of boom members 13a, 13b and 13c, and can be extended and retracted by an extendable and retractable cylinder (not shown) provided in the boom.

At the tip of the boom 13, a workbench swinging mechanism with an articulated arm is provided. A vertical post 18 is pivotally supported on the tip of the tip boom member 13c, and a workbench 21 is disposed on the vertical post 18 via an arm 17 and a bracket 16. The vertical post 18 is used for the leveling cylinder 1 regardless of the up and down state of the boom 13.
Always kept perpendicular to the ground by 4a and 14b.

FIG. 2 shows in detail the mounting relationship between the boom tip portion and the workbench of the aerial work vehicle of FIG. 1 in order to explain the load detection device of the present invention. Also, FIG.
FIG. 3 is a sectional view taken along line AA in FIG. 2. Vertical post 18
One end of the arm 17 is pivotally supported so as to be horizontally pivotable, and the bracket 16 is pivotally supported by the pivot 29 on the upper surface of the other end of the arm 17 so as to be horizontally pivotable. For example, if the elbow part of the arm is a vertical post 18 in the human body, the bracket 16 hits the hand part, and the workbench 21 attached to the tip of the bracket 16 acts like an elbow, that is, a cup held in the hand. The vertical post 18 can be freely moved on the horizontal plane with the fixed point. This is a work table swing mechanism using an articulated arm.

The bracket 16 has a side shape and a Y-shape laid down sideways, and the Y-shaped legs are pivotally supported on the tip of the arm 17. The Y-shaped opening of the bracket 16 is formed in a U-shape, and the upper link member 2 for suspending the workbench 21 is attached to the inner vertical surface of the U-shape.
In order to loosely insert 2 and the lower link member 23, two rectangular parallelepiped spaces 16c and 16d are formed in the horizontal direction with a predetermined interval. Further, pin holes 16e and 16f are provided so as to cross the center lines of the rectangular parallelepiped spaces 16c and 16d at right angles in the horizontal direction.

The workbench 21 is formed of a bucket 21b on which a worker is placed and on which materials and the like are loaded, and a boss 21a as a mounting portion of the bucket 21b. Boss 21
a has a rectangular parallelepiped shape, and the upper link member 22 and the lower link member 23 are loosely inserted on the front surface of the boss 21a, that is, the surface facing the bracket 16, as in the two rectangular parallelepiped spaces 16c and 16d of the bracket 16. Two rectangular parallelepiped spaces 21c and 21d are formed in the horizontal direction at predetermined intervals. In addition, these rectangular parallelepiped spaces 21c
Pin holes 21e and 21f are provided so as to cross the center lines of the electrodes 21 and 21d at right angles in the horizontal direction.

The upper and lower link members 22 and 23 are rectangular parallelepiped spaces 16c, 16d, 2 of the bracket 16 and the boss 21a.
1c and 21d are loosely inserted, and pin holes 16e, 16f, 2
The link pin 24 is fitted into the shafts 1e and 21f, so that the link pin 24 is pivotally supported by the bracket 16 and the boss 21a.
Since the upper link member 22 and the lower link member 23 have the same shape, and the pin holes 16e, 16f, 21e, and 21f provided in the bracket 16 and the boss 21a are located at equal intervals in the vertical direction, The boss 21a and the upper and lower link members 22 and 23 form a parallel link mechanism.

Further, a load cell 25 is provided as a load detecting means on the upper surface of the U-shaped downward projecting portion of the bracket 16 as the base portion (fixed side) of the parallel link mechanism. The upper surface of the load cell 25 receives the lower surface of the boss 21 a of the work table 21 as the movable portion of the parallel link mechanism. The bracket 16, the boss 21a, and the load cell 25
And the vertical link members 22 and 23 in relation to
Are configured to remain substantially horizontal. Therefore, the force Fv acting on the load cell 25 from the workbench 21 via the parallel link mechanism becomes the same as the vertical load W acting on the workbench 21.

This is because the moment due to the vertical load W on the workbench 21 is the horizontal tensile force Fh1 acting on the upper link member 22 or the horizontal compressive force Fh2 acting on the lower link member 23, and the distance between the link members. This is because it is canceled out by the moment formed by the product. The magnitude of the moment due to the vertical load W changes in accordance with the change in the loaded load and the change in the load position. In response to the change in the moment, the horizontal pulling force Fh1 to the upper link member 22 and the lower link member 23 are applied. Since the horizontal compressive force Fh2 changes proportionally, the moment from the vertical load W is always canceled by the moment due to the product of the horizontal tensile force Fh1 or the horizontal compressive force Fh2 and the distance between the link members. Therefore, a force Fv equal to the vertical load W from the workbench 21 acts on the load cell 25.

Strictly speaking, since the upper link member 22 and the lower link member 23 are supported at both ends by the bracket 16 and the boss 21a, a load for one link member is added to the workbench 21. ing. Therefore,
If only the weight of one link member and the weight of the workbench 21 including the two link shafts 24 are corrected from the detected value obtained by the load cell 25, only the load will be obtained. .

As described above, since the load detecting device is constructed so that the lateral force does not act on the load cell 25 and the influence of the moment is removed, the worker moves in the workbench 21 and the load is moved. Even if the location of the tool or the like is changed, the load cell 25 is hardly affected. Therefore, it is possible to accurately detect the loaded load.

Further, a stopper 26 is provided on the inner surface of the U-shaped upward projecting portion of the bracket 16 facing the upper surface of the boss 21a as a cushion against vibration and the like of the work vehicle 10 at traveling. The stopper 26 only has a cushioning function and does not affect the load detection of the load cell 25. However, this stopper 26 acts as a cushioning force on the upper surface of the boss 21a when there is no load on the workbench 21, and the average number of workers who board the workbench 21 during actual work at a high place. Boss 2 when the weight exceeds a payload of 70kg
It is preferable that the material and the thickness are determined so that the contact with the upper surface of 1a is interrupted and the drag force as the cushion is lost.

The present invention is not limited to the above embodiment, but the upper link member 22 and the lower link member 23 constituting the parallel link mechanism are respectively provided in plural and the bracket 16 is provided.
Alternatively, it may be arranged outside the boss 21a. Further, if the upper and lower link members are arranged in parallel, the lengths of the link members may be different from each other, and the load can be detected even if the link members are inclined. But,
To bring the detection of the vertical load component close to 100%, the link members should be arranged substantially horizontally. Obviously, further improvements, improvements, changes and the like can be made within the scope of the claims of the present invention.

[0022]

As described above, according to the load detecting device for an aerial work vehicle of the present invention, the bracket provided at the tip of the boom, the work table, the horizontally extending upper link member, and A parallel link mechanism is configured with the lower link member extending in parallel. With this parallel link mechanism, the moment generated by the workbench load is offset by the moment due to the product of the horizontal tension force on the upper link member or the horizontal compression force on the lower link member and the distance between the upper and lower link members. For this reason, only the vertical load acts on the load detecting means arranged on the bracket so as to receive the vertical load of the workbench, while the influence of the moment is removed. Therefore, in the workbench, the worker may move or tools,
Even if a material or the like is moved, the load detection means is less likely to be affected, and accurate load detection is possible. As described above, since the load detection is hardly affected by the movement of the workbench load position, it is possible to accurately detect the workbench load even on an aerial work vehicle having a workbench swing mechanism using an articulated arm. .

[Brief description of drawings]

FIG. 1 is an overall side view of an aerial work vehicle according to the present invention.

FIG. 2 is a detailed view of a load detection device for an aerial work vehicle.

FIG. 3 is a sectional view taken along line AA in FIG. 2;

[Explanation of symbols]

 10 work platform 11 vehicle body 12 swivel base 13 boom 15 hoisting cylinder 16 bracket 17 arm 18 vertical post 21 work table 22 upper link member 23 lower link member

Claims (1)

[Claims] 1. A bracket disposed at the tip of a boom of an aerial work vehicle, a work platform on which materials and the like are loaded, and one end of which is pivotally supported by the work platform and extends substantially horizontally to form the bracket. An upper link member having the other end pivotally supported, and a lower link member extending parallel to the upper link member, having one end pivotally supported at the work table and the other end pivotally supported at the bracket. A high place including a support portion provided on the bracket and receiving a vertical load from the workbench, and a load detection means sandwiched and disposed between the workbench opposite to the support part. Load detection device for work vehicles.