JPS61273500A - Bracing device in height service car - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for preventing swing of a boom in an aerial work vehicle.

(Prior Art) As shown in FIG. 3, an aerial work vehicle has a swivel base 2 installed on the top of a vehicle body 1 so as to be horizontally rotatable, and a telescoping boom 3 is attached to the swivel base 2 by a lift cylinder 4. Mounted so that it can be raised or lowered. Further, a workbench 5 is attached to the tip of the boom 3, and an operator performs operations such as extending/contracting, raising/lowering, and rotating the boom 3 on the workbench 5.

Incidentally, the boom 3 is rotated by a hydraulic motor.
Expansion, contraction and undulation are performed by hydraulic cylinders.

(Problems to be Solved by the Invention) However, in the above-mentioned aerial work vehicle, especially when the boom 3 is extended, immediately after the boom 3 is rotated or raised and stopped at a desired position. boom 3
Due to the elasticity of the workbench, horizontal and vertical vibrations occur on the workbench, causing problems such as being unable to work until the vibrations have subsided, and giving the worker a sense of fear.

Therefore, a technical problem to be solved by the present invention is to suppress as much as possible the shaking of the workbench that occurs immediately after the boom is stopped.

(Means for solving the problem) The technical means for solving the above problem is that in an aerial work vehicle, a work platform steady rest device is installed on the boom tip side, and a swing detection device that detects the swing of the boom is used. When the boom is stopped, the shake signal output from the shake detector is compared with the allowable vibration reference value, and when the shake signal exceeds the allowable vibration reference value, the boom drive device is This includes a vibration damping control device that outputs a drive signal in the opposite direction to the vibration direction.

(Function) When a shake occurs on the workbench immediately after the workbench stops at a desired position by manual operation by an operator, this shake is detected by the shake detector. The vibration damping control device controls a control valve of a boom drive device in response to the detected shake, and drives the drive device in a direction opposite to the shake, thereby suppressing the shake of the work platform.

(Example 1) Hereinafter, Example 1 of the present invention will be specifically described based on FIGS. 1 to 3. In FIG. 3 showing the whole of the aerial work vehicle, 1 is the vehicle body, 2 is a swivel table installed horizontally rotatably on the vehicle body 1, and 3 is a lift cylinder 4, which is attached to the swivel table 2 so as to be vertically movable. The boom is raised and lowered by a telescope cylinder (not shown) and extended and contracted by a telescope cylinder (not shown), and a workbench 5 is installed at the tip of the boom.

As shown in FIG. 1, the swivel table 2 is driven by a hydraulic drive device. That is, the drive pinion 7 of the hydraulic motor 6 meshes with the large driven gear 8 on the swivel base 2 side, and the electromagnetic swivel control valve 9 controls the flow direction of the hydraulic oil from the hydraulic pump 10 to control the hydraulic pressure. Controls the drive/stop and rotation direction of the motor 6.
It is supposed to be done. The workbench 5 has a horizontal (
An accelerometer 11 is installed as a shake detector in the horizontal) direction, and a detection signal from the accelerometer 11 is input to a vibration damping control device 12, which receives the acceleration detection signal from the accelerometer 11. The swivel base 5 according to
outputs a control signal for the control valve 9 in the drive device.

FIG. 2 shows a detailed configuration of the vibration damping control device 12 including the accelerometer 11. As shown in FIG.

The accelerometer 11 has a weight m fixed to the end of a piezoelectric element PE made of polycrystalline ceramic such as barium titanate, and the other end of the piezoelectric element PE is fixed to a base B so that the boom 3 can be moved in the left-right direction. When the vibration swings, the piezoelectric element PE is configured to generate a voltage corresponding to the magnitude of the vibration. Further, the voltage corresponding to the horizontal vibration output from the accelerometer 11 is amplified by the amplifier AMP in the vibration damping control device 12, and when the boom 3 swings to the right, for example, a positive voltage is outputted from the accelerometer 11. In this case, the configuration is such that a negative voltage is output.

The voltage v1 output from the amplifier AMP is input to the non-inverting input terminal + of the comparator CPI and the inverting input terminal + of the comparator CP2, and is compared with the reference voltage V, REF corresponding to the permissible vibration of the boom 3. . Reference voltage V, R
EF is the Zener diode ZD when current is applied to the Zener diode ZD from the control power supply VCC via the resistor R.
This uses the output voltage of the

Comparator CP1. CP2 is the voltage ■1, respectively.
As a result of comparing and calculating the reference voltages V and REF, if the voltage v1 is greater than the reference voltages V and REF, the voltage signal VL
Or output VR. In this case, the voltage signal VL is output from the comparator CP1, and if the boom 3 swings to the left more than permissible, the voltage signal VR is output from the comparator CP2. Furthermore, when the voltage signal VL is output from the comparator CP1, the transistor TR1 is turned on.
However, transistors TR1 and TR2 are provided so that when voltage signal VR is output from comparator CP2, transistor TR2 is turned on.

On the other hand, the solenoid 5OLI- of the control valve 9 that controls the hydraulic motor 6 in the swing drive device of the boom 3
L and 5OL1-R are controlled by the left and right rotation contact signals generated by manual operation of the boom rotation operation switch TS, and when the boom rotation operation switch TS is in the neutral position, the ON signals of the transistors TR1 and TR2 are activated. It is configured to operate by. That is, a magnetic contactor MS is provided which is excited when the boom rotation operation switch TS is in the neutral position, and the boom rotation operation switch T
When S is manually operated in the left or right rotation direction, the solenoid 3011-L and the left rotation contact are connected via the normally closed contact BC1 or BO2 of the magnetic contactor MS, and the solenoid 5OLI-R and the right rotation The pivot contacts are configured to be connected respectively. When the boom rotation operation switch TS is set to the neutral position, the boom 3 is stopped, the magnetic contactor MS is energized, the normally closed contacts BC1 and BC2 are opened, and the normally open contacts MA1. M
A2 closes. As a result, if the boom 3 is vibrating beyond the allowable value, the transistor TRI or TR2 is turned ON.
Therefore, the solenoid 5OL1-L or 5OL1-R is energized from the battery BA via the normally open contact MA1 or MA2.

This embodiment is constructed as described above, and its operation will be explained below.

When the boom rotation operation switch TS is operated on the workbench 5, the solenoid 8011 of the control valve 9
-Ll and tSOLl-R are energized L and the control valve 9 is switched to the left or right rotation side, thereby driving the hydraulic motor 6 to rotate the boom 3 leftward or rightward. When the desired position is reached, the boom rotation operation switch TS is returned to the neutral position to stop the rotation operation of the boom 3, and the boom 3 swings to the left or right due to inertia, and the accelerometer 11 indicates the magnitude of the swing. A voltage corresponding to the vibration damping control device 12 is outputted to the amplifier AMP of the vibration damping control device 12.

The amplifier AMP outputs a positive voltage (1) when the boom 3 swings to the right, and a negative voltage (1) when the boom 3 swings to the left. When the polarity of voltage v1 is positive and greater than reference voltages V and REF, voltage VL is output from comparator CP1 and transistor TR1 is turned on. As a result, the solenoid 5OL1-1 is energized from the battery BA, and the control valve 9 is switched to the left rotation side, so that the hydraulic motor 6 slightly rotates the boom 3 to the left, suppressing vibrations in the right direction. On the other hand, if the polarity of the voltage v1 is negative and greater than the reference voltage V, REF, the comparator CP
Voltage VR is output from 2, and transistor TR2 is turned on.
Therefore, in this case, solenoid 5OL1-
R is energized, the control valve 9 is switched to the right rotation side, and the hydraulic motor 6 slightly rotates the boom 3 to the right, suppressing leftward vibration.

As mentioned above, the vibration immediately after the boom 3 stops is detected by the accelerometer 1.
1, the direction of the vibration is determined, and the boom 3 is slightly rotated in a direction opposite to the vibration direction, thereby making it possible to suppress (dampen) the vibration of the boom 3.

(Example 2) Next, a second embodiment of the present invention will be explained based on FIG. 4.

In this embodiment, in addition to the horizontal shaking in the first embodiment, pitching is also suppressed. That is, an accelerometer 13 as a pitching detector is installed on the workbench 5, and a detection signal from the acceleration lever 13 is input to the vibration damping control device 12, and the vibration damping control device 12 moves the boom 3 up and down. The lift control valve 14 for controlling the lift cylinder 4 to be operated is configured to be switched and controlled in accordance with the pitching of the workbench 5.

In addition, the lift control valve 14 regarding pitching
The specific control circuit for this is the same as that for the above-mentioned lateral vibration, so the explanation thereof will be omitted. Therefore, according to the second embodiment, it is possible to suppress the horizontal and vertical shaking of the workbench 5 and the shaking in both directions, and the workbench 5 is stabilized.

Note that the vibration damping control device 12 described in the embodiment is not limited to that shown in the drawings, and can be replaced with a microcomputer, for example. Furthermore, the vibration detector is not limited to the accelerometers 11 and 13.

(Effects of the Invention) As detailed above, according to the present invention, in an aerial work vehicle, it is possible to suppress vibration in the horizontal direction or vertical direction immediately after the boom has been moved to the desired position. The workbench is stabilized, and the worker can perform predetermined work safely and efficiently.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; Fig. 1 is a control system diagram showing the steady rest device of Embodiment 1, Fig. 2 is an electric circuit diagram of the vibration damping control device, and Fig. 3 is the entire aerial work vehicle. Side view, 4th
The figure is a control system diagram showing the steady rest device of the second embodiment. ” 3...Boom 5...Workbench 9...
・Control valve 11... Accelerometer 12...
Vibration damping control device 13... Accelerometer Applicant Toyota Industries Corporation Agent Patent attorney Hidehiko Okada (2 others) Figure 4

Claims (1)

[Claims] A run-out detector installed at the tip of the boom detects the swing of the boom, and when the boom is stopped, the run-out signal output from the shake detector is compared with the allowable vibration standard value, and the run-out signal is determined to be within the allowable vibration standard. A steady rest device for an aerial work vehicle, comprising a vibration damping control device that outputs a drive signal in a direction opposite to the direction of boom vibration to a boom drive device when a value exceeds a certain value.