JPH0231520Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an operating hydraulic circuit for an aerial work vehicle.

High-altitude work vehicles are equipped with an upper operating valve and a lower operating valve on the platform and on the ground respectively, and are normally operated from the platform, but can be operated from the ground in the event of an accident on the platform. It is configured as follows. However, the conventional operating hydraulic circuit
As shown in the figure, an upper operating valve 4 and a lower operating valve 3
and the actuator 5 were simply connected in parallel. Therefore, even if the lower operating valve 3 is switched to the b position when the upper operating valve 4 is in the a position, the pipe 11 is connected to the pipe 13, the upper operating valve 4, and the lower operating valve 3. Since the pipe 9 communicates with the tank pipe 8, no pressure is built up in the pipe 11, and the actuator 5 cannot be controlled.

The present invention was developed in view of the above circumstances, and provides an operating hydraulic circuit for an aerial work vehicle that can reliably control the actuator by operating the lower operating valve regardless of the state of the upper operating valve. The purpose is to

Examples of the present invention will be described below. Second
As shown in the figure, the pressure oil discharged from the pump 22 is sequentially sent to the lower operating valve 23 and the upper operating valve 24 through a pipe 26 and a pipe 27, and the lower operating valve 23
is connected to a pilot-type 3-position, 6-port switching valve 37 by pipes 31 and 32, the upper operating valve 24 is also connected to a switching valve 37 by pipes 33 and 34, and the switching valve 37 is connected to a pilot type switching valve 37 by pipes 35 and 36. The actuator 25 is connected to the actuator 25 . Pilot pipes 38 and 39 of the switching valve 37 are connected to pipes 32 and 31 connecting the lower operating valve 23 and the switching valve 37, respectively, and the switching valve 37 is switched in conjunction with the operation of the lower operating valve 23. When the switching valve 37 is in the neutral position, the upper operating valve 24 and the actuator 25 are communicated and the pipes 31 and 32 of the lower operating valve 23 are blocked, and when the switching valve 37 is switched from the neutral position to positions c and d, the upper operating valve 2
4 are shut off, and the lower operation valve 23 and the actuator 25 are communicated with each other.

With the above configuration, when only the upper operation valve 24 is operated, the switching valve 37 is held in the neutral position, so the upper operation valve 24 and the actuator 25 are communicated through the pipes 33 and 34 and the pipes 35 and 36. The actuator 25 is controlled by operating the upper operation valve 24. When the lower operation valve 23 is switched from the neutral position to the a position or the b position, pressure is built up in the pipe line 32 or the pipe line 31, and the pilot pipe line 38,
39, the switching valve 37 is switched to the c position or the d position, the pipes 33 and 34 of the upper operating valve 24 are cut off, and the pipes 31 and 32 of the lower operating valve 23 and the pipes 35 and 36 of the actuator 25 are communicated. Therefore, the actuator 25 is controlled by the lower operation valve 23 regardless of the operation of the upper operation valve 24.

FIG. 3 shows the circuit of an actual aerial work vehicle, and shows the upper operation valves 46, 47, 48, 49, the lower operation valves 42, 43, 44, 45, and the actuator 5.
4, 55, 56, and 57, respectively.
0, 51, 52, 53 are provided, and all actuators 54, 55, 56, 57 are connected to the upper operation valve 4.
Regardless of the states of the lower operating valves 42, 43, 44, and 45, priority is given to controlling them.

As described above, according to the present invention, in an aerial work vehicle equipped with operating valves on the upper and lower parts, when the lower operating valve is operated, the actuator is reliably activated by the lower operating valve, regardless of the state of the upper operating valve. Since the present invention can be controlled, the present invention is effective in improving the operability and safety of an aerial work vehicle equipped with control valves at the upper and lower parts.

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram showing a conventional example, and FIGS. 2 and 3 are hydraulic circuit diagrams showing an embodiment of the present invention. 23...Lower operation valve, 24...Upper operation valve, 2
5...Actuator, 37...Switching valve.

Claims (1)

[Scope of utility model registration request] In an operating hydraulic circuit for an aerial work vehicle that is equipped with an upper operating valve and a lower operating valve and controls the same actuator by selectively operating both operating valves, a pipe line connecting the operating valves and the actuator is provided. , a pilot-type switching valve is arranged that, when switched, blocks the pipe line of the upper operation valve and communicates the lower operation valve with the actuator, and when the lower operation valve is operated, only the lower operation valve communicates with the actuator. An operating hydraulic circuit for an aerial work vehicle, characterized in that a pilot pipe line of a switching valve is connected to a pipe line connecting a lower operating valve and a switching valve.