JPH0721517Y2 - Operating equipment for aerial work platforms - Google Patents

Description

[Detailed Description of Device] a. The present invention relates to an aerial work vehicle having a work platform at the tip of a boom, and further relates to an operating device for controlling the operation of the boom.

(Prior Art) An aerial work vehicle (see FIG. 2) is provided with a work platform for an operator to ride on at the tip of a boom that can be raised and lowered, and the work platform is moved to an arbitrary position by operating the boom. . The operation unit for controlling the operation of the boom is often provided at two positions on the workbench side and the vehicle body side for convenience of work. These two operating units consist of hydraulic valves etc. that are switched by lever operation, and as shown in FIG.
An operation unit on the vehicle body side (referred to as a lower operation valve unit 41) uses an operating oil supplied through a main oil passage 42 connected to the hydraulic pump P to control the operation of a hydraulic actuator 43 such as a cylinder that operates a boom. On the other hand, the operation unit on the workbench side (called the upper operation valve unit 44)
Is a carryover oil passage 45 connected to the lower operation valve unit 41.
Via the hydraulic oil supplied to the hydraulic actuator 43 when the lower operation valve unit 41 is in a neutral state.
Is arranged and configured to control the operation of the. Therefore, when the lower operation valve unit 41 is operated by the lever, hydraulic oil is blocked from flowing into the carry-over oil passage 45 by the lower operation valve unit 41, so that even if the upper operation valve unit 44 is operated, Cannot be controlled. On the contrary, when the lower operation valve unit 41 is in the neutral state,
The boom can be controlled by the upper operation valve unit 44.

In the operating device having such a configuration, both operating valve units
A lower emergency stop valve 46 is provided on the main oil passage 42 as a boom emergency stop circuit in the case where the boom cannot be controlled due to a malfunction of the valves in 41 and 44 or an operator's erroneous operation.
However, an upper emergency stop valve 47 is arranged on the carryover oil passage 45. The lower emergency stop valve 46 is attached to the vehicle body side (for example, in the vicinity of the lower operation valve unit 41), and when the lever switch is turned on, the main oil passage 42 is communicated with the oil tank T, and the working oil is transferred to the oil tank T. Stop the boom operation by draining to. Further, the upper emergency stop valve 47 is attached to the workbench side (for example, in the vicinity of the upper operation valve unit 44), and the operation operation of the boom is disabled mainly due to defective operation of the valve in the upper operation valve unit 44. At this time, by turning on the lever switch, the carryover oil passage 45 can be communicated with the oil tank T, and the operation of the boom can be stopped.

An example of such an emergency stop circuit is proposed in Japanese Utility Model Laid-Open No. 64-26696. In this case, as shown in FIG. 4 which is shown only below the line AA in FIG. 3, a main unload valve 56 is branched from the main oil passage 42 instead of the lower emergency stop valve 46, and an oil tank is provided. It is arranged on the drain oil passage 56a connected to T. In addition,
In this operating device, the upper emergency stop valve 47 in FIG. 3 is not provided. The main unload valve 56 is an electromagnetic switching valve, and its solenoid is connected to an emergency stop signal line 55 in which a lower emergency stop switch 51 and an upper emergency stop switch 54 are arranged in series. In addition, the lower emergency stop switch 51
Is attached to the vehicle body side, and the upper emergency stop switch 54 is attached to the workbench side.

Both of these emergency stop switches 51 and 54 are off (that is,
When the emergency stop line 55 is opened), the solenoid is excited, the main unload valve 56 maintains the non-loaded state, and the boom is controlled by the upper or lower operation valve units 41 and 44. However, either the lower emergency stop switch 51 or the upper emergency stop switch 54 is turned on (that is,
When the emergency stop line 55 is shut off, the main unload valve 56 is switched to the unload state, the main oil passage 42 is communicated with the oil tank T, and the upper and lower operation valve units are connected.
No hydraulic fluid is supplied to either 41 or 44, and the boom stops.

(Problems to be solved by the invention) In such an emergency stop circuit of the operating device, in the former example (see FIG. 3), the upper emergency stop valve 47 is turned on to enable boom control by the upper operation valve unit 44. Even if you lose
Boom control by the lower operation valve unit 41 is possible.
Therefore, there is a problem that a worker on the ground may accidentally operate the lower operation valve unit 41 to operate the boom while the operation of the boom is stopped by the operator on the workbench. .

Further, in the latter example (see FIG. 4), when hydraulic oil flows into the upper operation valve unit 44, if a malfunction occurs such that the boom automatically operates and becomes uncontrollable, Even if the upper emergency stop switch 51 is turned on to stop the operation of the boom, if the operation of the main unload valve 56 is released, hydraulic oil may flow into the upper operation valve unit 44. The stop switch 51 cannot be turned off. Therefore, there is a problem that it is inconvenient because there is no means for lowering the work table to the ground.

In view of the above problems, in the present invention, when the upper emergency stop means is operated, the boom operation is disabled by both the upper and lower operation valve units, and thereafter the boom is operated by the lower operation valve unit. It is an object of the present invention to provide an operating device for an aerial work vehicle capable of canceling the emergency stop state so that the operation can be performed.

B. Configuration of the Invention (Means for Solving the Problems) In order to achieve the above object, in the present invention, an oil tank is provided on a main oil passage connecting a hydraulic power source and a lower operation valve unit arranged on the vehicle body side. Provided with a main unload valve that can be communicated, connected from the lower operation valve unit to the upper operation valve unit arranged on the workbench side, on the carry-over oil passage into which hydraulic oil flows when the lower operation valve unit is in the neutral state, A carryover unload valve that can communicate with the oil tank is provided, and a lower emergency stop switch that operates the main unload valve to communicate the main oil passage with the oil tank is provided on the vehicle body side. The load valve is operated to connect the carryover oil passage to the oil tank, and the main unload valve is operated to connect the main oil passage to the oil tank. An upper emergency stop switch is installed on the workbench side, and when the upper emergency stop switch is turned on, only the operation of the main unload valve is released to open the main oil passage to open the lower operation valve. A main unload release switch that enables the boom to be controlled by the unit is arranged on the vehicle body side.

(Operation) In such an operating device, for example, when the upper emergency stop switch is actuated when malfunction of the valve occurs in the upper operation valve unit, the carryover unload valve and the main unload valve are actuated. , The carryover oil passage and the main oil passage are connected to the oil tank, respectively, and the boom is stopped. At this time, boom operation cannot be performed by either the upper or lower operation valve unit. After this, when the main unload release switch is activated, the carryover unload valve remains in the unload state, only the main unload valve returns to the non-unload state, and the lower operation valve unit enables boom operation. A work platform stopped at a high place can be lowered to the ground.

(Embodiment) Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

First, the aerial work vehicle equipped with the operating device according to the present invention
Shown in the figure. A swivel base 2 is mounted on a vehicle body 1 of this aerial work vehicle. The swivel base 2 can swivel with respect to the vehicle body 1 by the operation of a swivel motor 3 which is hydraulically operated. A base end portion of a telescopic boom 5 formed by inserting the tip boom 4b into the base boom 4a is pivotally attached to the swivel base 2. The boom 4 can be lifted and lowered by expanding and contracting a hydraulically operated hoisting cylinder 5 arranged between the swivel base 2 and the base end boom 4a. Further, the tip boom 4b can be expanded and contracted by the expansion and contraction operation of the hydraulically operated expansion and contraction cylinder 6 mounted inside the boom 4. A bucket (workbench) 7 for mounting a worker is attached to the tip of the tip boom 4b.

A lower operation valve unit 21 for operating the operation of the boom 4 is attached to the upper part (vehicle body side) of the swivel base 2, and the work table 7 also has an upper operation valve unit 21 for the same purpose.
21 is installed.

For this reason, by operating the turning motor 3, the hoisting cylinder 5, and the telescopic cylinder 6 based on the lever operation or the like in the lower or upper operation units 11 and 12, a high-altitude work for moving the bucket 7 to a desired position is performed. be able to. A leveling device (not shown) is provided between the bucket 7 and the telescopic boom 4, and the leveling device keeps the bucket 7 horizontally during the work. Further, outriggers 8 are arranged at four positions on the front, rear, left, and right of the vehicle body 1. When performing work, the outriggers 8 are extended to the side of the vehicle and extended downward to support the vehicle body 1.

The boom 4 of the above-structured work vehicle is controlled by the operating device shown in FIG.

This operation device includes a hydraulic pump (hydraulic power source) P, a lower operation valve unit 11, an upper operation valve unit 21, and an emergency stop circuit.
It consists of 30.

The suction port of the hydraulic pump P is connected to the oil tank T, and the discharge port is connected to the main oil passage 12. The tip of the main oil passage 12 is connected to the lower operation valve unit 11. This lower operation valve unit 11 is composed of a lower swing control valve 13, a lower undulation control valve 15, and a lower expansion / contraction control valve 16, and these control valves 13, 15, 16 respectively include a swing motor 3, an undulation cylinder 5, and The supply / discharge control of the hydraulic oil to / from the telescopic cylinder 6 is performed. Further, when all of these control valves 13, 15, 16 are in the neutral state, a communication oil passage connected to the main oil passage 12 is formed in the lower operation valve unit 11. This communication oil passage is connected to a carry-over oil passage 17 extending from the vehicle body 1 side to the work table 7 side along the boom 4. The tip of the carryover oil passage 17 is connected to the upper operation valve unit 21. The upper operation valve unit 21 is composed of an upper swing control valve 23, an upper undulation control valve 25, and an upper expansion / contraction control valve 26, and these control valves 23, 25, 26 are control valves in the lower operation valve unit 11. Similar to 13, 15, and 16, the supply / discharge control of the hydraulic oil to / from the swing motor 3, the hoisting cylinder 5, and the telescopic cylinder 6 is performed. Further, when all of these control valves 23, 25, 26 are in the neutral state, a communication oil passage connected to the carryover oil passage 17 is formed in the upper operation valve unit 21. This communication oil passage is connected to the oil tank T.

The emergency stop circuit 30 includes a main unload valve 31, a carryover unload valve 32, a lower emergency stop switch 33, an upper emergency stop switch 34, a relay CR, and a main unload release switch 35.

The main unload valve 31 is an electromagnetic switching valve provided on the main oil passage 12, that is, on the main drain oil passage 31 a that branches from the main oil passage 12 and is connected to the oil tank T. The main unload valve 31 is a two-position valve having an unload position for opening the main drain oil passage 31a and a non-unload position for closing the main drain oil passage 31a, and its switching operation is performed by the solenoid 31b. It is performed by excitation and non-excitation. When the solenoid 31b is in the excited state, it is in the non-unload position, and in the non-excited state, it is in the unload position. A main unload signal line 36 connected to the power source B is connected to the solenoid 31b.

On this main unload signal line 36, the solenoid
From the side closer to 31b, the lower emergency stop switch 33 and the relay C above
The R relay contacts CRa are arranged in series. The lower emergency stop switch 33 is attached in the vicinity of the lower operation valve unit 11 and shuts off the main unload signal line 36 when pushed down (turned on). In addition, relay contact CRa
The main unload release switch 35 is connected in parallel with. The main unload release switch 35 is attached near the lower operation valve unit 11 and opens the main unload signal line 36 when pushed down (turned on). The lower emergency stop switch 33 and the main unload release switch 35 are connected in series.

The carryover unload valve 32 is an electromagnetic switching valve provided on the carryover drain oil passage 32a that branches from the carryover oil passage 17 and is connected to the oil tank T.

This carryover unload valve 32 is also the main unload valve
The configuration is the same as that of 31, and the switching operation is similarly performed by energizing and de-energizing the solenoid 32b. A carryover unload signal line 37 connected to the power source B is connected to the solenoid 32b. An upper emergency stop switch 34 is arranged on the carryover unload signal line 37. The upper emergency stop switch 34 is attached near the upper operation valve unit 21, and when it is pushed down (turned on), the carryover unload signal line 37.
Shut off. Also, carryover unload signal line
The relay CR is connected to 37. This relay CR
In the energized state, the relay contact CRa is closed to open the main unload signal line 36, and in the non-energized state, the relay contact CRa is opened to open the main unload signal line 36.
Shut off. The main unload signal line 36 and the carryover unload signal line 37 are normally energized, and the solenoids 31b and 32b are excited.

Next, the operation of the boom operation device will be described.

An operator on the ground uses the lower operation valve unit 11 to boom 4
When operating the operation of, the hydraulic oil discharged from the hydraulic pump P flows into the lower operation valve unit 11 and each control valve
Depending on the operation of 13, 15, 16 hydraulic actuators 3, 5,
6 to operate the boom 4. At this time, since the above-mentioned communication oil passage is not formed in the lower operation valve unit 11, the working oil does not flow into the carryover oil passage 17 and is not supplied to the upper operation valve unit 21 either. Therefore, even if the upper operation valve unit 21 is operated, the operation of the boom 4 cannot be controlled. In this case, for example, the control valves 13, 15,
When the boom 4 is out of control due to a malfunction of any of the 16 or the like, the operator must operate the lower emergency stop switch 33
Turn on. As a result, the solenoid 31a is de-energized and the main unload valve 31 is switched to the unload position, so that the hydraulic oil is drained to the oil tank T and the boom 4
Will stop operating.

Next, when the operator on the bucket 7 operates the boom 4 using the upper operation valve unit 21, the hydraulic pump P
The hydraulic oil discharged from the carrier oil passage 17 and the carry-over oil passage 17 formed in the lower operation valve unit 11 in the neutral state.
Flow into the upper operation valve unit 21 via the
Hydraulic actuators 3, 5, depending on the operation of 3, 25, 26
6 to operate the boom 4. In this case, for example, when the boom 4 is out of control due to malfunction of any of the control valves 23, 25, 26, the operator turns on the upper emergency stop switch 34. This allows
The solenoid 32b is de-energized, and the carryover unload valve 32 switches to the unload position. At the same time, the relay CR is turned off and the relay contact CRa is opened, so that the main unload signal line 36 is cut off and the main unload valve 31 is switched to the unload position. As a result, the operation control of the boom 4 cannot be performed by either the upper operation valve unit 21 or the lower operation valve unit 11.
The boom 4 is reliably stopped.

When the main unload release switch 35 is turned on while the upper emergency stop switch 34 is turned on, the main unload signal line 36 is opened via the main unload release switch 35 and the solenoid is again opened.
31b is excited and the main unload valve 31 is switched to the non-unload position. As a result, the operation control of the boom 4 can be performed only by the lower operation valve unit 11, and the bucket 7 can be lowered to the ground to rescue the operator who has boarded the bucket 7. At this time, since the carryover unload valve 32 remains in the unload position, the hydraulic oil does not flow into the upper operation valve unit 21.

C. Effect of the Invention As described above, when the operating device of the present invention is used, malfunction occurs in the upper operation valve unit, and when a worker on the work table operates the upper emergency stop switch, only the carryover unload valve is operated. In addition, since the main unload valve is also in the unload state, it is possible to prevent the boom once stopped from operating due to an erroneous operation by an operator on the ground. Also, if you want to operate the boom to lower the workbench to the ground after the boom has been stopped by such an upper emergency stop switch, operate the main unload release switch to operate the upper part that has a malfunction. The operation of the boom can be operated by the lower operation valve unit without flowing hydraulic oil into the operation valve unit, and the workbench can be lowered to the ground to easily rescue the worker on the workbench.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of an operating device according to the present invention, FIG. 2 is a perspective view of an aerial work vehicle equipped with the operating device, and FIGS. 3 and 4 are hydraulic pressures of a conventional operating device. It is a circuit diagram. 3 ... Revolving motor, 4 ... Boom 5 ... Elevating cylinder, 6 ... Telescopic cylinder 7 ... Bucket 11, 41 ... Lower operating valve unit 12, 42 ... Main oil passage 17, 45 ... Carryover oil passage 21, 44 ... Upper operating valve unit 31, 56… Main unload valve 32… Carryover unload valve 33, 51… Lower emergency stop switch 34, 54… Upper emergency stop switch 35… Main unload release switch

Claims (1)

[Scope of utility model registration request] 1. A boom provided on a vehicle body at least capable of undulating, and a work platform provided at the tip of the boom.
A lower operation valve unit that is disposed on the vehicle body side and that controls the operation of the boom using operating oil that is supplied via a main oil path that is connected to a hydraulic pressure source, and a carryover oil path that is connected to this lower operation valve unit. An operating device for an aerial work vehicle comprising an upper operating valve unit that controls the operation of the boom by using operating oil supplied when the lower operating valve unit is in a neutral state, on the main oil passage. A main unload valve that is provided and is in communication with the oil tank; a carryover unload valve that is provided on the carryover oil passage and is in communication with the oil tank; and a main unload valve that is provided on the vehicle body side. A lower emergency stop switch that operates a load valve to connect the main oil passage to the oil tank; and a carryover anchor that is disposed on the workbench side. An upper emergency stop switch that operates a guard valve to connect the carryover oil passage to the oil tank, and operates the main unload valve to connect the main oil passage to the oil tank; and to the vehicle body side. When the upper emergency stop switch is turned on, the operation of the boom is controlled by the lower operation valve unit by releasing only the operation of the main unload valve and opening the main oil passage. An operating device for an aerial work vehicle, comprising an enabling main unload release switch.