JPS6232237Y2 - - 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 as well as a work platform, the operating device for operating the boom is installed in two places: the upper part on the work platform and the lower part on the vehicle body, etc., but the operating device for the lifting device is Since it is installed only on the workbench, 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 it connects the drain circuit of the hydraulic motor that drives the lifting device to the pilot port of the switching valve that stops the hoisting operation of this hydraulic motor, and also connects the drain circuit to the shaft-off. The object of the present invention is to provide an operation regulating device for an aerial work vehicle equipped with a lifting device that can regulate the operation of the lifting device with a simple configuration by communicating with an oil tank through a valve. .

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a telescopic boom 3 is pivotally supported on a rotating base 2 provided on a vehicle body 1, and the telescopic boom 3 is extended and contracted by a built-in telescopic cylinder (not shown) and is The telescopic boom 3 rises and falls in the vertical direction by expanding and contracting, and a work platform 4 and a lifting device 5 are supported in equilibrium at the tip of the telescopic boom 3.

FIG. 2 shows a hydraulic circuit, in which the discharge pipe of the pump 8 is connected to a lower control valve 9, and by a pipe 15 to an upper control valve 23 and a control valve 10 of the lifting device. The operating valve 10 and the hydraulic motor 11 that drives the winch of the lifting device are connected by a hoisting side pipe 16 and a lowering side pipe 17, and the hoisting side pipe 16 and the lowering side pipe 17 have two ports and two positions. The valves are connected via a pilot switching valve 12, which is normally held at position a to cut off the connection between both pipes 16 and 17, and when switched to position b by pilot pressure, both pipes are connected. Road 16,1
7 are communicated via a check valve.

The pipe line 18 of the drain circuit of the hydraulic motor 11 is branched into a pipe line 19 and a pipe line 20, the pipe line 19 is connected to the pilot port of the pilot switching valve 12, and the pipe line 20 is connected to the pilot port of the pilot switching valve 12 via the electromagnetic shift-off valve 13. Connected to oil tank 7, shaft off valve 13
is normally held at position a, and the pipe line 20 communicates with the oil tank 7. The shaft-off valve 13 is provided with a bypass line 21, and a low-pressure relief valve 14 is inserted into the bypass line 21.

With the above configuration, the shaft off valve 13 is always
is held at position a, the lifting device 5
The drain circuit of the hydraulic motor 11 is connected to the oil tank 7.
Since no pressure is generated in the drain circuit and therefore the pilot switching valve 12 is held in position a, the lifting device 5 can be hoisted and lowered. When restricting the hoisting operation of the lifting device 5, a signal is sent to the shaft-off valve 13 to switch the shaft-off valve 13 to position b. When the shaft-off valve 13 is switched to the b position, the conduit 20 of the drain circuit is cut off, so that the pressure in the drain circuit rises to the set pressure of the relief valve 14, and the pilot switching valve 12 is switched to the b position. b of switching valve 12
The position is such that both pipe lines 16 and 17 are connected via a check valve that prevents the flow of pressure oil from the lowering side pipe line 17 side of the hydraulic motor 11 to the hoisting side pipe line 16. Although the lifting device 5 can be lowered, the hydraulic motor 11 is not driven so that the pressure oil in the hoisting side pipe 16 flows through the switching valve 12 to the lowering side pipe 17 during the hoisting operation.

As described above, according to the present invention, the operation of the upper lifting device can be regulated by operating the lower operating section, and since the upper and lower operating sections are connected only by hydraulic piping, the upper and lower operating sections are connected only by hydraulic piping. Thus, there is provided an operation regulating device for a vehicle for aerial work equipped with a lifting device, which can be used even in a vehicle for aerial vehicle with electrical insulation between the operating parts of the vehicle.

[Brief explanation of the drawing]

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, 9...
Lower operating valve, 10... Operating valve of lifting device, 1
1...Hydraulic motor, 12...Pilot switching valve,
13...Shaft off valve, 14...Relief valve,
16... Winding-up side pipe line, 17... Rolling-down side pipe line,
18, 19, 20...Drain pipe line, 23...Upper operation 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 drain circuit of a hydraulic motor that drives the lifting device is connected to the pilot port of a switching valve that stops the hoisting operation of this hydraulic motor, and the drain circuit is An operation regulating device for an aerial work vehicle equipped with a lifting device, characterized in that a circuit is communicated with an oil tank via a shut-off valve.