JPH0533517Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an operation control device for an aerial work vehicle.

(Prior art) Generally, an aerial work vehicle is equipped with outriggers with jacks attached to four locations on both the front and rear sides of the vehicle body, and a telescoping boom is pivotably supported on a swivel platform mounted on the vehicle body. , a workbench is installed at the tip of the boom, and during work, the outriggers are extended to the sides and the jacks are extended to securely support the vehicle body, and then the workbench is moved to an appropriate space to perform various tasks. I'm starting to do it.

If the jack is not extended, the electromagnetic switching valve will be in the neutral position, making it impossible to perform various operations (Japanese Patent Laid-Open No. 60-6595).

(Problem to be solved by the present invention) Therefore, if there is a poor contact or disconnection in the circuit to the electromagnetic switching valve, the pressure oil of the hydraulic pump will bypass to the oil reservoir, causing problems during work at high places. If the above-mentioned wire breakage occurs, the worker will be left alone on the workbench located at a high place, which is extremely dangerous.

The present invention has been devised in view of the above-mentioned points, and provides an operation control device for a high-altitude work vehicle in which the electromagnetic switching valve can be easily returned to the operating position.

(Example) An example of the present invention will be described below with reference to the drawings.
Reference numeral 1 denotes the body of a high-altitude work vehicle, and a swivel base 2 is pivotally mounted to the rear of the vehicle body 1 so as to be horizontally swivelable. A multi-stage telescoping boom 3 whose base end is pivoted and can be raised and lowered is provided on the swivel base 2, and a workbench 6 is attached to the tip of the boom 4.

The swivel base 2 is connected to a hydraulic motor 7 and rotated, and a luffing cylinder 8 is installed between the telescopic boom 3 and the swivel base 2 to raise and lower the boom 3. A telescopic cylinder 9 is installed inside the boom 3, and the telescopic boom 3 is extended and contracted by this cylinder.

In addition, there are outriggers 1 at 4 locations on both the front and rear sides of the vehicle body 1.
A jack 11 is provided at the tip of the outrigger 10 so as to be extendable to the side, and a jack 11 is provided at the tip of the outrigger 10 so as to be extendable and retractable downward, each of which supports the vehicle body 1 during work.

On the other hand, as shown in the hydraulic system diagram in FIG. 2, the aerial work vehicle includes an outrigger cylinder 12 that extends the outrigger 10, a jack cylinder 13 that extends and contracts the jack 11, a hoisting cylinder 8 that hoists the telescopic boom 3, A rotation motor 7 that rotates the swivel base 2 and a telescoping cylinder 9 that extends and retracts the telescopic boom 4 are respectively provided. I'm starting to be able to do it.

Further, the hydraulic motor 7 is connected to a switching valve 1 connected in parallel.
5 and 15', the elevating cylinder 8 is controlled by operating the switching valves 16 and 16' connected in parallel, and the telescopic cylinder 9 is controlled by operating the switching valves 17 and 17' connected in parallel, respectively. Oil is supplied to perform boom-related operations such as the rotation of the swivel base 2 and the elevation and contraction movements of the telescoping boom.

The switching valves 15, 16, and 17 are arranged in the operating section 20 on the vehicle body, and the switching valves 15', 16', and 17' are arranged in the operating section 21 on the workbench 6.

By the way, between the aforementioned switching valve groups 18, 19 and switching valve groups 15, 16, 17, there is an electromagnetic switching valve 22.
is installed, and the switching is controlled only when the electromagnetic part 22a is energized as described later, and the hydraulic pump 1
The discharged oil from 4 is transferred to the downstream side of the switching valve 15,
16 and 17, and is normally in the neutral position so that pressurized oil from the hydraulic pump is returned to the oil reservoir.

Each jack 11 also has an electrical contact that closes when the jack cylinder 13 extends beyond a certain level.
An LSI is arranged, and on the other hand, an electric contact LS2 is arranged in the driver's cab, which is operated to close when a control lever for controlling the connection and disconnection of a power take-off device (not shown) is operated.

Further, an electric contact LS3 is disposed which is operated to close in conjunction with the contraction side operation of an operating lever (not shown) for controlling the expansion and contraction of the jack 11.

SW is an operating switch, R1 and R2 are relays, r
1 and r2 are contacts of relays R1 and R2.

Next, the operation of the present invention will be described. First, the operator turns on the main switch (not shown) and operates the power take-off device. Power supply voltage is supplied and the hydraulic pump 14 is driven, completing preparations for operation. .

After that, if the switching valves 18 and 19 are operated to extend the outrigger cylinder 12 and the jack cylinder 13, the outrigger 10 and the jack 1
1 is activated to the working position.

In this case, since each electrical contact LS1 is closed when all the jacks 11 are fully extended,
The power supply voltage is applied to the electromagnetic section 2 via the electrical contact LS1.
2a, the electromagnetic switching valve 22 is switched to the operating position.

Next, the switching valve 1 is operated by the operating section 20 or 21.
By appropriately selecting and controlling the switching valves 5 to 17 or the switching valves 15' to 17', the workbench 6 can be moved to an appropriate position in the space.
A worker on the workbench 6 can perform various tasks.

Here, if a disconnection or poor contact occurs in the circuit to the electromagnetic part 22a of the electromagnetic switching valve 22, the electromagnetic switching valve 22 returns to the neutral position, and the hydraulic pump 1
As a result of the pressure oil from 4 returning to the oil reservoir,
Boom-related operations by the hydraulic actuators 7, 8, and 9 become impossible.

In this case, the operating switch SW may be pressed. That is, as a result of the closing operation of the actuation switch SW, a self-holding circuit of the relay R1 is formed, so that even if the actuation switch SW is removed, the electromagnetic part 22a continues to be energized through its contact r1.
The electromagnetic switching valve 22 is switched to the operating position.

Therefore, boom-related operations can be performed by the hydraulic actuators 7, 8, and 9, and after the work platform 6 is lowered from an appropriate space, it can be returned to the traveling position and returned to the maintenance shop.

Note that in order to be able to travel from the ground position of the jack 11, it is necessary to reduce the jack cylinder 13, and as long as this operation is performed, the self-holding circuit to the electromagnetic part 22a of the electromagnetic switching valve 22 will be cut off, and the next operation will be interrupted. The electromagnetic switching valve 22 is in the neutral position.

That is, by operating the jack cylinder 13 on the contraction side, the operating lever (not shown) connects the electric contact LS.
3 is closed and the self-holding circuit to the electromagnetic section 22a is opened via the contact r2 of the relay R2, and as a result, the boom-related operation is resumed without remembering that the circuit to the electromagnetic switching valve 22 is malfunctioning. It is possible to prevent this from occurring.

In addition, if the power take-off device is disconnected, the electrical contact
LS2 is opened and similarly cuts off the self-holding circuit to the electromagnetic section 22a.

In addition, in this embodiment, the electromagnetic switching valve 22 is the switching valve 1.
Although the switching valve 18 is located between 8 and 15, the position of the switching valve 18 is not limited to this, and is arranged so that the expansion control of the jack cylinder 13 can be performed without being affected by the electromagnetic switching valve 22. It is fine if it is done.

(Effects) As described above, with the present invention, even if the boom-related operation becomes impossible due to a break in the circuit to the electromagnetic switching valve, the switching control of the electromagnetic switching valve can be forcibly controlled. This makes it possible to lower workers from high places to the ground.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is an overall side view of the aerial work vehicle, FIG. 2 is a simplified hydraulic system diagram, and FIG. 3 is an electric circuit diagram. 3...Boom, 11...Jacket, 22...Solenoid switching valve, LS1, LS2, LS3...Electric contact.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In the middle of hydraulic piping that communicates between a hydraulic pump driven via a power take-off device and a switching valve that controls boom-related operations, there is a In an aerial work vehicle equipped with an electromagnetic switching valve that shuts off the pressure oil supply and supplies pressure oil to the downstream side by switching control only when the jack is in the operating position, the solenoid section of the electromagnetic switching valve is activated. An operation control device for an aerial work vehicle, characterized in that an electromagnetic switching valve can be forcibly switched and controlled via the operating switch by linking a switch. (2) The operation control device for an aerial work vehicle according to claim 1, wherein a self-holding circuit can be formed in the electromagnetic portion of the electromagnetic switching valve by closing the operation switch. (3) The self-holding circuit by the operating switch is canceled in connection with the disconnection operation of the power take-off device or the reduction operation of the jack. Operation control device for work vehicles.