JPS641359Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an operation regulating device for an aerial work vehicle equipped with a lifting device.

In an aerial work vehicle equipped with a lifting device along with a work platform at the tip of the boom, there are two operating devices for operating the boom (elevating, extending/contracting, turning, etc.): the upper part on the work platform, and the lower part on the ground or on the vehicle body. However, since the operating device for the lifting device is installed only on the work platform, it is easy to control the operation of the boom, but it is difficult to control the operation of the lifting device. .

The present invention was developed in view of the above circumstances, and the pressure necessary for the hoisting operation of the lifting device is added to the pipeline connecting the hydraulic pump, which is the power supply source for the working device, and the directional control valve that controls the lifting device. Provide a pressure reducing valve with a pressure set lower than the pressure required for lowering the lifting equipment and higher than the pressure required for the lowering operation of the lifting equipment,
By connecting the front and back of this pressure reducing valve by a bypass pipe that normally communicates and is shut off when regulating the hoisting operation of the lifting device, the operation of the lifting device can be easily regulated at the lower part. The object of the present invention is to provide an operation regulating device for a high-altitude work vehicle equipped with a lifting device.

An embodiment of the present invention will be described below with reference to the drawings. As shown in Fig. 1, a rotating base 2 driven by a hydraulic motor 8 is provided on a vehicle body 1, and a telescopic boom 3 is pivotally supported on the rotating base 2. The telescopic boom 3 is extended and retracted by a built-in telescopic cylinder 7, and is raised and lowered in the vertical direction by a hoisting cylinder 6. A hydraulic motor 9 is attached to the tip of the telescopic boom 3.
The lifting device 5 driven by the lifting mechanism 4 and the work platform 4 are supported in a balanced manner.

FIG. 2 shows a hydraulic circuit, in which the discharge pipe of the hydraulic pump 14 is branched, and one discharge pipe 18 is connected to the pressure reducing valve 1.
The other discharge pipe 19 is connected to each actuator 6, 7, through a 3-port, 2-position electromagnetic switching valve 16, which is connected to a directional switching valve 10 provided on the workbench and which controls a lifting device. The discharge pipe 18 between the pressure reducing valve 15 and the directional switching valve 10 and the electromagnetic switching valve 16 are connected by a bypass pipe 17. Pressure oil supplied to the switching valve 16 is selectively supplied to the bypass pipe 17 and each of the directional switching valves 11, 12, and 13 by switching the electromagnetic switching valve 16. The pressure reducing valve 15 is set to have a pressure lower than the pressure required for the lifting operation of the lifting device and higher than the pressure required for the lowering operation of the lifting device, and the carryover pipe 20 of the directional control valve 10 is set as a check valve. The directional control valves 11, 12, and 13 are connected to the discharge pipe 19 via a pipe 21, and each of the directional control valves 11, 12, and 13 is configured to be operable from an upper part on the workbench and a lower part on the ground or the vehicle body.

With the above configuration, the electromagnetic switching valve 16 is normally energized and held at the b position, so the oil discharged from the hydraulic pump 14 is supplied to the directional switching valve 10 of the lifting device through the bypass pipe 17. Each actuator 6, 7,
8, the hydraulic motor 9 and other actuators 6, 7, 8 of the lifting device 5 can be operated normally. When regulating the operation, when the electromagnetic switching valve 16 is de-energized and switched to the a position, the pressure oil reduced by the pressure reducing valve 15 is supplied to the directional switching valve 10 of the lifting device 5, and the other directional switching valves valve 11,
12 and 13 are supplied with pressure oil that is not depressurized through the discharge pipe 19, so the lifting device 5 can perform a lowering operation, but cannot perform a hoisting operation, and the other actuators 6, 7, and 8 are It can be operated normally.

Note that by using a separate shut-off valve or the like, it is also possible to restrict the operation of the other actuators 6, 7, 8 at the same time as the lifting device 5.

As described above, the present invention can regulate the operation of the lifting device installed at the tip of the boom by communicating and blocking the bypass line of the pressure reducing valve installed at the bottom of the aerial work vehicle. According to the invention, there is provided an operation regulating device for an aerial work vehicle equipped with a lifting device that can regulate the operation of the lifting device at the bottom without requiring special wiring or piping to the tip of the boom. .

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a side view of an aerial work vehicle equipped with a lifting device, and FIG. 2 is a hydraulic circuit diagram. 1...Vehicle body, 2...Swivel base, 3...Telescopic boom, 4...Work platform, 5...Lifting device, 6...
Lifting cylinder, 7... Telescopic cylinder, 8, 9...
Hydraulic motor, 10, 11, 12, 13... Directional switching valve, 14... Hydraulic pump, 15... Pressure reducing valve, 1
6...Solenoid switching valve, 17...Bypass pipe line, 1
8, 19...Discharge pipe line, 20...Carryover pipe line, 21...Check valve, 22...Relief valve.

Claims (1)

[Scope of utility model registration request] In an aerial work vehicle equipped with a work platform and a lifting device at the tip of the boom, the device is lifted onto a conduit 18 that connects a hydraulic pump 14 that is a power supply source for the working device and a directional control valve 10 that controls the lifting device 5. A pressure reducing valve 15 is provided whose pressure is set to be lower than the pressure required for the hoisting operation of the lifting device 5 and higher than the pressure necessary for the lowering operation of the lifting device 5, and the front and back of the pressure reducing valve 15 are normally communicated, Lifting device 5
An operation regulating device for an aerial work vehicle equipped with a lifting device, characterized in that the lifting device is connected by a bypass conduit 17 that is cut off when regulating the hoisting operation of the vehicle.