JPS6124320B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a boom in an aerial work vehicle that freely moves a work platform attached to the tip of the boom by extending/contracting, elevating, and horizontally turning the boom to perform various types of high-altitude work. The present invention relates to a device that is used both for emergency stopping of related operations and for starting a hydraulic pump driving prime mover that controls these operations.

As an aerial work vehicle, a swivel platform is mounted on the vehicle body, and a telescoping boom is installed on the swivel platform, which can move up and down freely and has a work platform attached to the tip.Each related movement of the boom is controlled by a hydraulic pump mounted on the vehicle. This is accomplished by operating a plurality of hydraulic drive devices using pressurized oil, and work vehicles that use the vehicle's own traveling engine as the driving engine for the hydraulic pump are commonly used.

If the engine of this type of aerial work vehicle stops for some reason during work, the supply of pressure oil from the hydraulic pump will stop, making it impossible to control the boom operation.

Therefore, in the event of engine trouble as described above, urgent measures are required to start the engine as soon as possible.

The present invention was invented in view of the above-mentioned points, and when an abnormal situation such as engine stoppage occurs during high-altitude work using a high-altitude work vehicle, a hydraulic pump driving prime mover is remotely controlled from a workbench. The present invention aims to provide a convenient prime mover starting device for driving a hydraulic pump in an aerial work vehicle, which enables early restoration of the original state by starting the system.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Reference numeral 1 indicates the body of a working vehicle, 2 indicates a swivel base pivoted to the rear of the vehicle body for horizontal rotation, and 3 indicates a base end pivotably mounted on the swivel base. , a boom that can be raised and lowered freely,
The illustrated boom 3 has a telescoping main body boom 4 that extends and retracts in multiple stages, and a front boom 5 to which a workbench 6 is attached can be folded laterally.

The pivot of the swivel base 2 is connected to a hydraulic motor 7 for rotation, and a hydraulic cylinder 8 is installed between the main body boom 4 and the swivel base 2 to allow the boom 3 to move up and down. A hydraulic cylinder 9 is installed inside the body to extend and retract the main body boom 4. Although not shown in the drawings, it is appropriate to extend and fold the front boom 5 with respect to the main boom 4 using a hydraulic cylinder installed between the two.

The hydraulic motor 7 and hydraulic cylinders 8, 9 are incorporated into a hydraulic circuit shown in FIG. 2 and operate. That is, the hydraulic motor 7 is connected to the switching valve 1 in parallel.
1 and 11', the oil discharged from the hydraulic pump 10 is supplied and rotated, and the hydraulic cylinder 8 operates the switching valves 12 and 12' connected in parallel, and the hydraulic cylinder 9 operates the switching valves 13 and 13 connected in parallel. The pipes are arranged so that the oil discharged from the pump 10 is separately supplied by the operation 1 to cause the boom 3 to move up and down and extend and contract. The switching valves 11, 12, and 13 are arranged in an operating section 14 on the vehicle body, and the switching valves 11', 12', and 13' are arranged in an operating section 15 on the workbench.

On the other hand, the pipe inlet that supplies pressure oil to the switching valve groups 11, 12, and 13 on the vehicle body side and the switching valves 11', 12', and 13' groups on the work platform is connected in series to these valve groups. Emergency stop valves 16 and 16' are provided, and by operating the valves, the supply of pressure oil to the subsequent valve group is interrupted and bypassed to the tank 17.

Next, reference numeral 18 denotes an engine 20 which serves as a prime mover for the pump 10 and is inserted into the discharge oil pipe 19 from the pump 10.
With the start switch, the discharge oil pipe 19 is opened while the pump is operating.
When the pressure oil has a normal flow, that is, the pipe line 24
When the pressure is higher than the pressure in the discharge oil pipe 19, the switch is turned off, and the discharge oil pipe 19 is pressurized, and when this pressure relationship is reversed across the check valve 25, the switch is turned on. Although not shown, it is connected in parallel to the engine's main start switch and has the same effect.

However, since this switch needs to be held for a certain period of time until the engine starts, it is desirable to use a timer or the like. Reference numeral 21 denotes an oil passage bypass line provided at the oil passage cutoff position of the emergency stop valve 16' on the workbench side, and this line 21 always stores an appropriate amount of pressure oil and discharges it by operating the handle 23. A reverse feed ram 22 is inserted. However, when the switching valves 11, 12, 13 on the vehicle body side and the emergency stop valve 16 are in the neutral position and the oil discharged from the pump 10 is being circulated by the center bypass, when the emergency stop valve 16' is operated on the workbench 6, Subsequent operations by the switching valves 11', 12', and 13' on the workbench side are disabled.

When the engine stops during work at high places, after switching the emergency stop valve 16' to the upper position, press the handle 23 of the pressure oil return ram 22, and the oil in the ram 22 will flow into the discharge oil pipe. 19 flows back to the pump 10 side and the start switch 18 is turned on to start the engine. In this embodiment, the workbench is provided at the tip of a telescoping boom, but it can also be applied to other embodiments in which the workbench is provided at the tip of an elevating or retractable boom.

As explained above, according to the present invention, the operation of the boom installed in an aerial work vehicle is controlled from two locations, one on the vehicle body side and the other on the workbench attached to the tip of the boom, by operating a group of switching valves in a hydraulic pipeline. In this configuration, an emergency stop valve is installed in series in front of and upstream of the switching valve, so that abnormal situations can be prevented from occurring due to boom-related operation by the worker on the work platform or by a supervisor on the ground monitoring the work. When this occurs, this operation can be stopped immediately to avoid this problem, and an oil bypass pipe is provided at the oil flow cutoff position of the emergency stop valve on the workbench to prevent pressure oil from flowing back from the pipe. If it were possible to quickly start the pump drive prime mover by remote control and restore the original condition through a feed operation, it would be possible to work at heights with peace of mind even without the presence of ground personnel, and this start-up operation would reduce the pressure of the hydraulic pipes. Since it uses oil and does not require electrical wiring, it is possible to completely electrically insulate the boom or work platform, allowing safe work to be carried out without the risk of electric shock during electrical work at high places. Since one conduit is used in two ways: forward flow and reverse flow, its practical effects are great in terms of installation space and production costs.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention.
The figure is an overall side view of the work vehicle, Figure 2 is a hydraulic circuit diagram,
FIG. 3 is a partial hydraulic circuit diagram showing another embodiment. 1...Vehicle body, 2...Swivel base, 3...Boom, 4
... Main body boom, 5 ... Front boom, 6 ... Workbench, 7 ... Hydraulic motor, 8 ... Hydraulic cylinder,
9...Hydraulic cylinder, 10...Pump, 11...
...Switching valve, 12...Switching valve, 13...Switching valve, 1
4...Operation unit, 15...Operation unit, 16...Emergency stop valve, 17...Tank, 18...Start switch,
19...discharge oil pipe line, 20...engine, 21...
...Oil bypass pipe line, 22...Pressure oil return ram, 2
3...Handle, 24...Pipeline, 25...Check valve, 26...Switching valve.

Claims (1)

[Scope of Claims] 1. An aerial work vehicle equipped with a boom on which a work platform for aerial work is attached on the vehicle body, and boom-related operations are performed by a plurality of hydraulic drive devices disposed at various locations. A switching valve group for controlling the operation of the hydraulic drive device is disposed on the workbench, and an emergency stop valve is arranged in series at a position upstream in front of the switching valve group, and the switching valve group of the emergency stop valve An emergency stop device/hydraulic pump for an aerial work vehicle, characterized in that an oil bypass pipe is provided at a position where the oil flow is cut off, and the bypass pipe is provided with a starting operation device for a prime mover for driving the hydraulic pump. Drive motor starting device. 2. Emergency stop in the aerial work vehicle as set forth in claim 1, wherein the prime mover start operation device comprises a hydraulic start switch communicating with the pump discharge oil pipe and a pressure oil return means. Equipment/hydraulic pump drive prime mover starting device.