JPH0547193Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is based on a vehicle body, in which a boom with a workbench attached to its tip is disposed via a swivel platform, and boom-related operations are controlled from the base end of the boom. When the lower hydraulic control valve group is disposed on the section or the swivel platform and is supplied with pressure oil from a hydraulic pump via a high-pressure oil line, and the lower hydraulic control valve group is disposed on the tip of the boom or the workbench and is in neutral, The present invention relates to a safety device for an aerial work vehicle that is operated by both upper hydraulic control valve groups that are supplied with pressure oil from the hydraulic pump via a communicating carryover oil path.

(Conventional technology) Regarding the safety devices of conventional aerial work vehicles, the second
This will be explained based on FIG. FIG. 2 is an explanatory diagram of the aerial work vehicle, in which a boom 3 with a work platform 2 attached to its tip is disposed on a vehicle body 1 via a swivel platform 4. A swing motor 5 (not shown in FIG. 2) is arranged between the vehicle body 1 and the swivel base 4, so that the swivel base 4 can freely rotate relative to the vehicle body 1.
A hoisting cylinder 6 is arranged between the boom 3 and the boom 3 at a proper position, and the boom 3 can be raised and lowered with respect to the swivel base 4. The boom 3 is constructed of a multi-stage boom, and a telescopic cylinder 7 (not shown in FIG. 2) is disposed inside the boom 3 so as to be telescopic. In this way, boom-related operations can be performed by driving each hydraulic actuator.

Next, as shown in FIG. 3, each of the hydraulic actuators is connected to a lower part of the hydraulic actuator that is supplied with pressure oil from a hydraulic pump 9 via a high-pressure oil passage 8 provided at the base end of the boom 3 or the swivel base 4. A hydraulic control valve group 10 and an upper section that is supplied with pressure oil from the hydraulic pump 9 via a carryover oil passage 11 that is disposed at the tip of the boom 3 or the workbench 2 and communicates with the lower hydraulic control valve group 10 when it is in neutral. Pressure oil is supplied from both sides of the hydraulic control valve group 12, so that it can be operated from both sides. An emergency stop unload valve 13 is provided in the high pressure oil passage 8 at the front stage of the lower hydraulic control valve group 10, and this valve is connected to an upper emergency stop switch 14 or a lower hydraulic control valve disposed near the upper hydraulic control valve group 12. Lower emergency stop switch 15 located near the valve group 10
, the boom-related operation is stopped when an abnormal situation occurs during the boom-related operation. In addition, a work switch 16 ( This switch will not turn ON unless the person operating the switch always operates it, and it is a switch that is always OFF, so it is an automatic return type switch, for example, it is equipped with a foot petal and is activated by stepping on this foot petal. There is a foot switch that does not operate unless it is depressed.This foot switch will be explained below.) is wired in series with the emergency stop switches 14 and 15, so that when the foot switch 16 is not activated, the unload valve 13 is activated. There is. In other words, the unload valve 13 for emergency stop is replaced by the foot switch 16.
It is also used as an unload valve that is linked to the In this case, the emergency stop switches 14, 15
The unload valve 13 must be configured to unload when the operator is operating the work platform 2 and when the foot petal inside the work platform 2 is not depressed. ), there is a problem in that it is not possible to operate the lower hydraulic control valve group 10 to perform boom-related operations. A manually operated push button switch 17 having the same mechanism (automatic return type) as the foot switch 16 was wired in parallel with the foot switch 16 and provided near the lower hydraulic control valve group 10.

(Problems to be Solved by the Present Invention) However, in such a configuration, when attempting to drive the boom 3 with the lower hydraulic control valve group 10, the lower hydraulic control valve group is pressed while pressing the push button switch 17 with one hand. In order to switch and operate 10,
For example, there was a problem in that the boom 3 could not be raised and rotated at the same time.

The present invention focuses on the fact that the only thing that needs to be controlled by the work switch 16 (foot switch) is the boom-related operation by the upper hydraulic control valve group 12 (operated from the work platform 2). 16 (foot switch) is connected to the carryover oil passage 1 which leads to the upper hydraulic control valve group 12 separately from the emergency stop unload valve.
1, the drawbacks of the prior art described above are solved.

(Means for solving the problem) The safety device for workers at heights of the present invention has a boom with a work platform attached to its tip disposed on the vehicle body via a swivel platform, and boom-related operations are controlled by the boom. a group of lower hydraulic control valves arranged at the base end of the boom or the swivel platform and supplied with pressure oil from a hydraulic pump via a high-pressure oil path; and a group of lower hydraulic control valves arranged at the tip of the boom or the work platform. In the aerial work vehicle, the high-pressure work is carried out by both upper hydraulic control valve groups that are supplied with pressure oil from the hydraulic pump via a carry-over oil passage that communicates when the vehicle is in neutral. An emergency stop unload valve is provided in the oil passage, and the emergency stop unload valve is connected to the emergency stop switch so as to unload when the emergency stop switch provided near the upper hydraulic control valve group is operated. A work switch is connected to the carryover oil passage leading to the upper hydraulic control valve group and is disposed at an appropriate position on the work bench, and is in a non-unload state when the work switch is operated and is in an unload state when the switch is not operated. It is characterized by the provision of an interlocking unload valve.

(Function) Since the unload valve linked to the work switch is arranged in the carryover oil passage leading to the upper hydraulic control valve group, even if the unload valve linked to the work switch enters the unload state, The lower hydraulic control valve group disposed in the preceding stage is not affected and can perform boom-related operations. Therefore, when no worker is on the workbench, there is no need to control the lower hydraulic control valve group while pressing the push button switch, and simultaneous operations can be easily performed.

(Embodiment) An embodiment of the safety device for a high-altitude work vehicle according to the present invention will be described below with reference to FIG. In FIG. 1, reference numerals 5 to 15 are the same as those explained in the prior art in FIG. 3, so their explanation will be omitted. Further, although the description of the aerial work vehicle has been explained using reference numerals 1 to 4 and 6 in FIG. 2, the same reference numerals as those mentioned above will be used in the following description as well.

In Fig. 1, reference numeral 19 is a work switch, which is built into a footpetal placed on the floor of the workbench 2, and consists of a footswitch that turns off when the footpetal is not depressed and turns on when the footpetal is depressed. . Reference numeral 18 denotes a solenoid type unload valve, which is disposed in the carrier oil passage 11 leading to the upper hydraulic control valve group 12. The foot switch 19 has one end connected to a power source and the other end connected to the unload valve 18,
When the foot switch 19 is turned on, the unload valve 18 is in a non-unloading state, and when the foot switch 19 is turned off, it is in an unloading state. The emergency stop unload valve 13 is a solenoid type unload valve, and is connected to a power source via an upper emergency stop switch 14 and a lower emergency stop switch 15 connected in series. The upper emergency stop switch 14 and the lower emergency stop switch 15 are switches that are always ON.
Normally, the emergency stop unload valve 13 is in the non-unload state, but when either the upper emergency stop switch 14 or the lower emergency stop switch 15 is operated and either switch is turned OFF, the emergency stop unload valve 13 is set to the non-unload state. Even if the load valve 13 is unloaded and the upper hydraulic control valve group 12 or the lower hydraulic control valve group 10 is operated, boom-related operations are not possible.

The safety device for the high-altitude work vehicle constructed in this way operates as follows. Now workbench 2
When a worker rides on the boom-related operation, the worker depresses the foot pedal to set the unload valve 18 to the non-unload state, and operates the upper hydraulic control valve group 12 to perform the boom-related operation. At this time, even if the upper hydraulic control valve group 12 is operated without depressing the foot pedal, the unload valve 18 will be in the unload state and boom-related operations cannot be performed. Therefore, when performing boom-related operations on the work platform 2, it is necessary to depress the foot pedal to operate the upper hydraulic control valve group 12. Boom-related operations will not occur due to an operator inadvertently touching the operating switch.

In addition, if an abnormal situation occurs during boom-related operation, either the worker on the work platform 2 operates the upper emergency stop switch 14, or the worker located near the lower hydraulic control valve group 10 The emergency stop switch 15 is operated and the emergency stop unload valve 13 is placed in the unload state, thereby disabling boom-related operations.

Next, when no worker is on workbench 2,
When operating the lower hydraulic control valve group 10 to perform boom-related operations, the unload valve 18 is in the unload state because no worker is on the work platform 2 and the foot pedal cannot be depressed. However, since the unload valve 18 is disposed in the carryover oil passage 11 leading to the upper hydraulic control valve group 12, boom-related operations can be performed by the lower hydraulic control valve group 10 without being affected by the unload valve 18.

In the above embodiment, the work switch 19 is a foot switch built into the foot pedal.
A normally OFF switch is arranged in the grip of each operating lever of the upper hydraulic control valve group 12, and these switches are connected in parallel, with a power source and the unloading valve 18 connected to both ends of the switch. When operating the lever to perform a boom-related operation, the boom-related operation may not be performed unless the switch is operated together with the switch disposed on the grip portion of the operating lever.

Furthermore, in the above embodiment, as shown in FIG. 1, the upper hydraulic control valve group 12 was composed of manual type hydraulic control valves, but instead of the manual type hydraulic control valves, it was composed of an electromagnetic proportional control valve group. It is also possible to similarly arrange an unload valve 18 in the carryover oil passage 11 leading to the electromagnetic proportional control valve group.
When arranging the electromagnetic proportional control valve group in this way, when the signal circuit that transmits the manipulated variable signal to the electromagnetic proportional control valve is disconnected, the electromagnetic proportional control valve will be in the neutral position due to the spring placed inside it. Generally, the working switch is connected in series to the signal circuit. By doing so, it is possible to configure the system without using the unload valve 18. In this case, the work switch may be disposed as a normally OFF switch in the grip of the signal generating operating lever that sends a manipulated variable signal to the electromagnetic proportional control valve, and may be connected in series to the signal generating circuit. Then, the above-mentioned switches arranged on the grips of the corresponding operating levers may be similarly connected in series to each signal circuit of each electromagnetic proportional control valve of the electromagnetic proportional control valve group.

(Effects of the invention) Since the present invention is configured and operates as described above, when no worker is on the workbench, the lower hydraulic control valve group can be operated while pressing the push button switch as in the prior art. It is not necessary, and simultaneous operations can be easily performed, which is highly effective.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the safety device of the vehicle for working at heights according to the present invention, Figure 2 is an explanatory diagram of the vehicle for working at heights, and Figure 3 is
The figure is an explanatory diagram of a conventional safety device for an aerial work vehicle. 1... Vehicle body, 2... Workbench, 3... Boom, 4
...Swivel base, 8...High pressure oil path, 9...Hydraulic pump, 10...Lower hydraulic control valve group, 11...Carryover oil path, 12...Upper hydraulic control valve group, 13...
...Emergency stop unload valve, 14... Emergency stop switch, 19... Work switch, 18... Work switch interlocking unload valve.

Claims (1)

[Scope of Claim for Utility Model Registration] A boom with a work platform attached to its tip is installed on the vehicle body via a swivel platform, and the boom-related operations are controlled by high-pressure oil installed at the base end of the boom or at the swivel platform. The lower hydraulic control valve group is supplied with pressure oil from the hydraulic pump via a carry-over oil line which is disposed at the tip of the boom or the workbench and communicates with the lower hydraulic control valve group when the lower hydraulic control valve group is in neutral. In an aerial work vehicle configured to operate by both the upper hydraulic control valve group, which is supplied with pressure oil from the An emergency stop unload valve is connected to the emergency stop switch so as to unload when the emergency stop switch provided near the upper hydraulic control valve group is operated. A high work area characterized in that a carryover oil passage is provided with a work switch-linked unload valve that is placed in a non-unload state when a work switch placed at an appropriate position on a work bench is operated and becomes an unload state when the work switch is not operated. Safety equipment for work vehicles.