JPH0371359B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a safe operation control device for an aerial work vehicle for safely performing each operation of raising/lowering, extending/contracting, traveling, and turning the boom of the aerial work vehicle. Regarding.

(Prior Art) Conventionally, a control circuit for safe driving operation using a foot switch in an aerial work vehicle has been constructed using a foot switch 2 as shown in Fig. 4.
1 is inserted into the power supply circuit, and the foot switch 2
The circuit is configured such that control power is supplied from the battery 22 to the analog controller 23 when the switch 1 is depressed.
Raise and lower the boom with control power supplied to 3.
When the respective operating levers 24 for telescopic, traveling, and turning operations are operated and an operating signal corresponding to the operating tilt angle is output to the analog controller 23, the analog controller 2
3 outputs a drive signal corresponding to this operation signal to the valve 25 provided in each hydraulic circuit for raising/lowering, extending/contracting, traveling, and swinging the boom, controls the valve 25, and drives the aerial work vehicle. It is something.

Therefore, safe driving is ensured by preventing the aerial work vehicle from being driven even if the operating lever 24 is operated unless the driver depresses the foot switch 21.

(Problems to be Solved by the Invention) In the above-mentioned conventional safe driving control circuit, if the foot switch 21 is turned on and off while the operating lever 24 is kept depressed, for example, the boom repeatedly moves up and down, or repeatedly runs and stops running. There was a problem that it was dangerous for drivers because of the

Therefore, in the present invention, the aerial work vehicle does not repeatedly drive even if the foot switch is turned on and off while the control levers are kept down, but by stepping on the foot switch after all the control levers are returned to neutral. The technical problem to be solved is to enable the operation of an aerial work vehicle using a control lever.

(Means for Solving the Problems) The technical means for solving the above problems is to raise and lower the swivel base, which is rotatably installed on the vehicle body, by the hydraulic drive of a lift cylinder, and by the hydraulic drive of a telescope cylinder. A high place where a telescoping boom is attached, and a work platform equipped with an operating lever and a foot switch at the tip of the boom for raising, lowering, extending and retracting the boom, as well as driving and turning using a hydraulic motor drive. In the work vehicle, signals corresponding to the operating inclination angle of each operating lever are inputted from each of the operating levers, and the operating speeds of the boom for raising/lowering, extending/contracting, and traveling or turning are calculated, and the drive corresponding to the same operating speed is performed. A valve control circuit is provided that outputs a signal to a valve provided in a hydraulic drive circuit for raising/lowering, extending/contracting, traveling, and turning the boom, and the valve control circuit is connected to the control lever when an ON signal from the foot switch is input. When the foot switch is operated, the drive signal is output to each corresponding valve to control the valve, while when the foot switch is once turned off, the output of the drive signal to the valve is stopped, and the respective operation lever is After the foot switch is turned on in a state where all the motors have returned to neutral, each of the driving operations is enabled by the operating lever.

(Function) According to the above configuration, when the driver is on the workbench of the aerial work vehicle and presses down on the foot switch, for example, when he or she pushes down the operating lever for traveling operation, the foot switch outputs an on signal and then operates the An operation signal corresponding to the operation inclination angle is output from the lever to the valve control circuit. The valve control circuit calculates the travel speed based on the operation signal corresponding to the operation inclination angle, and outputs a drive signal corresponding to the travel speed to a valve installed in the hydraulic circuit of the travel drive system to drive the travel hydraulic motor. Supply pressure oil and run the aerial work vehicle.

When the driver removes his/her foot from the foot switch while the aerial work vehicle is running, the on signal output from the foot switch to the valve control circuit turns off, and the valve control circuit cuts off the output of the drive signal to the valve. Stops the supply of pressure oil to the travel hydraulic motor and stops the aerial work vehicle from traveling.

In order for the driver to resume traveling of the aerial work vehicle, he must first return all the operating levers to neutral to set the output of the operating signal to zero, and then step on the foot switch again to have the foot switch output an on signal. By tilting the operation lever for traveling operation again in this state, the valve control circuit outputs a drive signal to the traveling driving valve, and the aerial work vehicle can be made to travel. Therefore, even if the user unconsciously steps on the foot switch while the operating lever for operating the vehicle is kept depressed, the aerial work vehicle will not move, allowing safe operation.

Note that although the above-mentioned effect is an example of traveling drive of an aerial work vehicle, the same effect applies to undulating, extending/contracting, or turning drive.

(Example) Next, an example of the present invention will be described with reference to the drawings.

As shown in FIG.
The converter 2 and the I/O port 3 are connected, while the output side of the microcomputer 1 is connected to the valves for driving the aerial work vehicle, that is, the boom hoisting drive valve V1 of the aerial work vehicle, and the boom telescoping drive valve V1. V
2. A digital controller 5 is provided to which a valve drive amplifier 4 is connected for supplying drive current to the travel hydraulic motor drive valve V3 and the swing hydraulic motor drive V valve 4, respectively. The A/D converter 2 includes an operating lever L1 for boom hoisting operation provided on the work platform of the aerial work vehicle;
A control lever L2 for boom telescoping operation, a control lever L3 for traveling operation, and an operation lever L4 for swinging operation are connected. The operation lever L
1 to L4 are provided with potentiometers (not shown) inside, and are configured to output a voltage proportional to the operating inclination angle from the potentiometers by tilting the operating lever from a neutral state. In addition, the above I/
A foot switch 6 is connected to the O port 3, which is depressed by the driver to output an on signal when driving the aerial work vehicle. Furthermore, control power is supplied from the battery 7 to the digital controller 5.

Next, the operation of the present embodiment with the above configuration will be explained by taking the traveling operation of an aerial work vehicle as an example. FIG. 2 shows that when the operating lever L3 for driving operation is tilted from the neutral state in the forward driving operation direction (+ side) or when it is turned down in the reverse driving operation direction (- side). This figure shows the nonlinear output characteristics of the valve drive signal with respect to the output operation signal corresponding to the operation lever inclination angle. This nonlinear output characteristic is stored as data in the storage section of the microcomputer 1. Further, FIG. 3 shows a flowchart of calculation and control of the microcomputer 1.

Next, the calculation and control of this embodiment will be explained with reference to FIG. When control power is supplied to the digital controller 5 in step ST1, the microcomputer 1 is initialized and initially sets a flag to 0, which is inverted each time the signal from the foot switch 6 is turned on and off. In step ST2, the microcomputer 1 determines whether the foot switch 6 is depressed and an on signal is output from the foot switch 6. If it is determined that the on signal is not output, the microcomputer 1 advances to step ST9 and sets the flag to 1. and step
In ST10, the output of the drive signal to the valve drive amplifier 4 is set to zero.

On the other hand, if the microcomputer 1 determines in step ST2 that the on signal is output from the foot switch 6, it proceeds to step ST2.
In ST3, it is determined whether the flag is 1 or 0, and if it is determined that the flag is 0, an operation signal corresponding to the operation inclination angle from the operation lever L3 is sent via the A/D converter 2 in step ST4. Enter. In the next step ST5, a drive signal is calculated based on the input operation signal and the nonlinear output characteristic data, and then in step ST6, the same drive signal is output to the valve drive amplifier 4, and the valve drive amplifier 4 drives the valve. A drive current is applied to the hydraulic motor drive valve V3 to control the valve and rotate the travel hydraulic motor, thereby causing the aerial work vehicle to travel.

On the other hand, if the microcomputer 1 determines that the flag is 1 in step ST3, it is determined in step ST7 whether or not the operating lever L3 is in the neutral state based on the signal from the operating lever L3. If it is determined that it is, the flag is set to 0 in the next step ST8, and the process returns to step ST2. If it is determined in step ST7 that the operating lever L3 is not in the neutral state, the process returns to step ST2.

As mentioned above, when the driver turns off the foot switch 6 while driving the aerial work vehicle,
Unless all operating levers are once returned to neutral, the vehicle is controlled in such a way that the vehicle cannot be driven even if the foot switch 6 is turned on again. That is, in order to restart an aerial work vehicle that has stopped once due to turning off the foot switch 6, the microcomputer 1 is made to recognize that all the operating levers have been returned to neutral, and then the foot switch 6 is turned on. Furthermore, it is necessary to operate the operating lever L3 after that, which prevents the aerial work vehicle from suddenly starting when the foot switch 6 is repeatedly turned on and off unconsciously while the operating lever is pushed down as in the past. let

In addition, in the explanation of the above-mentioned operation, an example of running operation was shown, but the raising/lowering, extending/contracting, or turning operation of the boom is also safely controlled in the same way.

(Effects of the Invention) As described above, according to the present invention, once the foot switch is turned off, in order to perform the next operation, it is necessary to turn on the foot switch again and return all operating levers to neutral. Since this is necessary, it has the effect of preventing danger due to unconscious driving by the driver and allowing the vehicle to work at heights to be operated safely.

[Brief explanation of drawings]

FIG. 1 is a control block diagram of an embodiment of the present invention.
FIG. 2 is a control characteristic diagram, FIG. 3 is an arithmetic control flowchart, and FIG. 4 is a conventional control block diagram. 1... Microcomputer, 2... A/D converter, 3... I/O port, 4... Valve drive amplifier, 5... Digital controller, 6... Foot switch, 7... Battery, L1 to L4... ...Operation lever, V1...Boom hoisting drive valve, V
2...Valve for driving the boom extension/contraction, V3...Valve for driving the traveling hydraulic motor, V4... Valve for driving the swing hydraulic motor.

Claims (1)

[Claims] 1 A boom that is raised and lowered by the hydraulic drive of a lift cylinder and extended and contracted by the hydraulic drive of a telescope cylinder is attached to a swivel platform that is rotatably installed on the vehicle body. In an aerial work vehicle having a work platform equipped with a control lever and a foot switch for each of traveling and turning operations driven by a hydraulic motor, each of the control levers corresponds to the operating inclination angle of each control lever. The system calculates the operating speeds of the boom for raising and lowering, extending and retracting, and traveling and turning, and sends drive signals corresponding to the operating speeds to the hydraulic drive circuits for the boom's raising and lowering, extending and contracting, traveling and turning. The valve control circuit is provided with a valve control circuit that outputs the drive signal to each corresponding valve when the operating lever is operated with an ON signal from the foot switch being input to the valve control circuit. On the other hand, when the foot switch is once turned off, the output of the drive signal to the valve is stopped, and when the foot switch is turned on with all the operating levers returned to neutral, the output of the drive signal is stopped. A safe driving control device for a high-altitude working vehicle configured to enable each of the driving operations described above using a control lever.