JPH0995966A - Two-piece boom type construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To operate first and second booms by one operation lever without providing a new operation lever or a pedal for operating the second boom, in a two-piece boom type construction machine. SOLUTION: A signal generator 12 inputs the angle signal θ1 of the first boom 6 of a potentiometer 14, the angle signal θ2 between the first boom 6 and the second boom 7 of a potentiometwew 15, and the signals of pilot pressure Pa, Pb generated by operation of an operation lever device 105 for pressure switches 16a, 16b. A signal E is output to an electromagnetic changeover valve 13 so that the pilot pressure is distributed to either of flow control valves 2, 3, and the electromagentic changeover valve 13 is controlled for changeover, and hence the pilot pressure from the operation lever device is distributed to the flow control valve 2 or 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-piece boom type construction work machine provided with an articulated front working device including a two-piece boom, and more particularly, to a first boom and a second boom constituting the two-piece boom. The present invention relates to a two-piece boom type construction work machine that facilitates operation.

[0002]

2. Description of the Related Art In general, a hydraulic excavator has four working members as a front working device: a boom, an arm, a bucket, and a swivel. These working members are driven by respective actuators, and these actuators are operated by moving the operating lever of the operating lever device. By the way, one operating lever can be moved in the front-back direction and the left-right direction, and two actuators can be operated at the same time. Therefore, in order to operate four actuators in a hydraulic excavator,
It has a book operating lever. By operating these with both hands, the four actuators can be operated simultaneously. It also has two actuators that drive the right and left travel devices for traveling.
To operate these, two operation levers are provided, and these are operated with both hands. However, as described above, when operating the front actuator, both hands are closed, and therefore the lever operation for the traveling device cannot be performed. Therefore, a pedal is attached to the operation lever device for the traveling device so that the two traveling devices can be operated with both feet. In this way, in the hydraulic excavator, the work can be performed by simultaneously operating the six actuators by using both hands and both feet.

By the way, in recent years, the use of hydraulic excavators has been further expanded, and there has been a strong demand for further improvement in workability due to expansion of the work range and the like. As a construction work machine having a new front structure for that purpose, a conventional boom is divided into a first boom and a second boom, and the second boom is attached to the first boom so as to be rotatable in the vertical direction. There is a two-piece boom type hydraulic excavator that can expand the working range by moving two booms. This hydraulic excavator requires an operating device for operating the actuator of the second boom. However, when a new operating device is provided for the second boom, the operator operates a total of seven actuators with five operating devices. As described above, both hands and feet of the operator are blocked to operate the conventional six actuators. Therefore, in order to operate the second boom, it is necessary to stop the operation of any other actuator and operate the operating device with an empty hand or foot.

For example, when an operation lever device is adopted as the operation device for the second boom, the operation by the other one operation lever is stopped to operate the second boom, and therefore two operation lever devices are used. The actuator cannot be operated. As a result, the combined operation of the front working device becomes impossible, and the working efficiency is greatly reduced. Therefore, in the actual two-piece boom hydraulic excavator, a pedal is used as the operating device for the second boom.

[0005]

As described above, the actual machine 2
In the peace boom hydraulic excavator, a pedal is used as an operation device for the second boom. However, it is difficult to handle complicated front work by the operation with the feet, and it is difficult to work cooperatively with the other four work members. Also, in terms of safety, many operating devices may cause an erroneous operation. Therefore, the operation of the second boom is performed only to change the front shape according to the work at the time of starting the work, and the second boom is not currently effectively utilized.

A first object of the present invention is to provide a first boom and a second boom with a single operating lever for a boom without providing a new operating lever or operating device such as a pedal for operating the second boom. It is to provide a two-piece boom type construction work machine capable of operating a.

A second object of the present invention is to provide a two-piece boom which can be operated with the same operation feeling as a conventional hydraulic excavator without providing a new operation device such as an operation lever or pedal for operating the second boom. Type construction work machine.

[0008]

In order to achieve the above-mentioned first object, the present invention provides a first boom mounted on an upper revolving structure so as to be vertically rotatable and a first boom vertically mounted on the first boom. 2 consisting of a second boom rotatably mounted
An articulated front working device including a piece boom, a first driving device that drives the first boom, a second driving device that drives the second boom, and an operation lever that instructs driving of the two-piece boom. In a two-piece boom type construction work machine including a device, a first boom detecting means for detecting a position of the first boom, and a second boom detecting means for detecting a positional relationship between the first boom and the second boom. And a signal from the operation lever device based on signals from the operation detection device that detects the operation state of the operation lever device, the first boom detection device, the second boom detection device, and the operation detection device. And a signal switching means for allocating the signal to any one of the second drive devices.

As described above, in the present invention, the signal from the operation lever device is sent to either the first or second drive device based on the signals from the first boom detecting means, the second boom detecting means and the operation detecting means. By providing the signal switching means for allocating to the first boom, the signal from one operation lever device can be transmitted in accordance with the position of the first boom, the positional relationship between the first boom and the second boom, and the operation state of the operation lever device. The second boom can also be moved by a signal from one operating lever device, which is distributed to both the first drive means for driving and the second drive means for driving the second boom. Therefore, it is possible to operate the first and second booms with one boom operation lever without providing a new operation lever or an operation device such as a pedal for operating the second boom. As a result, the original performance of the two-piece boom can be fully brought out without impairing safety, and workability can be improved.

In the above-mentioned two-piece boom type construction work machine, preferably, the signal switching means inputs signals from the first boom detecting means, the second boom detecting means, and the operation detecting means, and the first and the second detecting means. The signal generating means for determining which of the two booms is to be driven and outputting a signal according to the determination and the signal from the signal generating means for inputting the signal from the operating lever device to the first and second A signal transmission means for transmitting the signal to any of the driving devices, and the signal transmission means is preferably an electromagnetic switching valve.

In order to achieve the second object,
According to a second aspect of the present invention, in the above-mentioned two-piece boom type construction work machine, it is determined whether the signal switching means is an operation for raising or lowering the two-piece boom according to a signal from the operation detecting means. A signal from the boom detecting means determines whether or not the first boom has reached a maximum raised position or a maximum lowered position, and a signal from the second boom detecting means determines whether the first boom and the second boom are in contact with each other. Judge whether the angle is larger or smaller than the predetermined angle,
In the operation of raising the two-piece boom, when the angle between the first and second booms is less than or equal to a predetermined angle, the second boom is raised until the predetermined angle is reached, then the first boom is raised, and the first boom is raised. Reaches the maximum raised position, the second
When the signal is distributed to the first and second drive means so as to further raise the boom, and when the angle between the first and second booms is greater than or equal to a predetermined angle in the operation of lowering the two-piece boom, the first and second drive means are operated until the predetermined angle is reached. After lowering the second boom, lower the first boom, and further lower the second boom when the first boom reaches the minimum lowered position.
The signal is distributed to the driving means, and the predetermined angle between the first and second booms is preferably set to be substantially the same as the bending angle of the monoboom.

By distributing the signal from the operating lever device to the first and second drive devices as described above, when the angle between the first and second booms is at a predetermined angle by the operation of raising the two-piece boom, the above-mentioned operation is performed. Only the first boom goes up, 2
When the operation of lowering the piece boom causes only the first boom to lower when the angle between the first and second booms is at a predetermined angle, the predetermined angle is made substantially the same as the bending angle of the monoboom of the conventional monoboom hydraulic excavator. If set,
It can be operated with the same operation feeling as a conventional hydraulic excavator. Further, when the angle between the first and second booms is less than or equal to a predetermined angle by the operation of raising the two-piece boom, or when the first boom reaches the maximum raised position, only the second boom is raised and the two-piece boom is lowered. When the angle between the first and second booms is greater than or equal to a predetermined angle, or when the first boom reaches the minimum lowered position, only the second boom is lowered, so the two-piece boom moves further upward or downward, The work range can be expanded.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG.

Referring to FIG. 1, a two-piece boom type hydraulic excavator according to an embodiment of the present invention includes an upper swing body 100.
And a second boom 7 attached to the front part of the upper swing body 100 so as to be vertically rotatable and a second boom 7 attached to the tip of the first boom 6 so as to be vertically rotatable. Arms 8 and 8 attached to the tips of the peace boom 101 and the second boom 7 so as to be vertically rotatable.
An articulated front working device 102 including a bucket 9 attached to the tip of the robot so as to be vertically rotatable, a first drive device 103 for driving the first boom 6, and a second boom 7.
A second drive device 104 for driving the first and second booms 6, 7 and an operation lever device 105 for instructing the drive of the first and second booms 6, 7.

The first drive device 103 comprises a hydraulic cylinder 4 for driving the first boom 6 and a flow control valve 2 for controlling the flow of pressure oil supplied from the hydraulic pump 1 to the hydraulic cylinder 4. The second drive device 104 includes a hydraulic cylinder 5 that drives the second boom 7, and a flow rate control valve 3 that controls the flow of pressure oil supplied from the hydraulic pump 1 to the hydraulic cylinder 5.

The operation lever device 105 is an operation lever 10 operated by an operator, and a pressure reducing valve 1 for outputting a pilot pressure according to an operation direction and an operation amount of the operation lever 10.
1a and 11b, and the output port of the pressure reducing valve 11a is via pilot lines 17a, 18a, and 19a, and pilot operation parts 2a and 3a on the right side of the flow control valves 2 and 3 in the figure.
And the output port of the pressure reducing valve 11b is connected to the pilot operating portions 2b and 3b on the left side of the flow control valves 2 and 3 in the figure via pilot conduits 17b, 18b and 19b.

Further, the hydraulic excavator in this embodiment is provided at a mounting portion of the first boom 6 and the upper swing body 100, and has a potentiometer 14 for outputting an angle signal θ1 of the first boom 6 and the first boom 6. The operation lever 1 is provided at a mounting portion of the second boom 7 and is provided at a potentiometer 15 for outputting an angle signal θ2 between the first boom 6 and the second boom 7, and at output ports of the pressure reducing valves 11a and 11b.
Pilot pressure signals Pa and Pb generated by operating 0
A signal generator for inputting signals θ1, θ2, Pa, Pb from the potentiometers 14, 15 and the pressure switches 16a, 16b for outputting the pressure switches 16a, 16b for outputting, and generating and outputting a signal E based on these signals. 12, pilot lines 17a, 17b and pilot lines 18a, 1
8b and the pilot conduits 19a, 19b, and an electromagnetic switching valve 13 that is switched and controlled by a signal E from the signal generator 12.

In the signal generator 12, first the pressure switch 1
From the signals Pa and Pb from 6a and 16b, as shown in FIG. 2, the operating state of the operating lever device 10 is judged and the signal S1 is generated. Next, using the output signals θ1 and θ2 of the potentiometers 14 and 15 and the created signal S1,
A signal E is sent to the electromagnetic switching valve 13 according to the flowchart shown in
Is output.

In the above, the potentiometer 14 constitutes the first boom detecting means for detecting the position of the first boom 6, and the potentiometer 15 detects the second boom for detecting the positional relationship between the first boom 6 and the second boom 7. And the pressure switches 16a and 16b constitute the operating lever device 10.
The signal generator 12 and the electromagnetic switching valve 13 constitute the operation detecting means for detecting the operation state of the first boom detecting means 1.
4, second boom detecting means 15, operation detecting means 16a, 1
A signal (pilot pressure) from the operating lever device 105 is supplied to the first and second drive devices 103, 1 based on the signal from 6b.
The signal switching means for allocating to any one of 04 is configured.

The signal generator 12 includes a first boom detecting means 14, a second boom detecting means 15, and an operation detecting means 16.
The signal from a, 16b is input, it is determined which of the first and second booms 6, 7 is to be driven, and a signal generating means for outputting a signal E according to the determination is configured, and the electromagnetic switching valve 13 Constitutes a signal transmitting means for inputting the signal E from the signal generating means 12 and transmitting the signal (pilot pressure) from the operating lever device 105 so as to distribute the signal to one of the first and second drive devices 103 and 104.

Next, the operation of this embodiment will be described based on the block diagram of FIG. 2 and the flowchart of FIG. Note that, here, the angle between the first boom 6 and the second boom 7 shown in FIG. 1 is a predetermined angle, and the potentiometer 1
The operation from the state where the output signal θ2 of No. 5 is the predetermined value θ0 will be described. Further, the predetermined angle between the first boom 6 and the second boom 7 is set to be substantially the same as the bending angle of the boom in a normal monoboom hydraulic excavator.

First, when the operating lever 10 is not operated, the outputs Pa and Pb of the pressure switches 16a and 16b are output.
Since both are "OFF", the signal generator 12 determines that they are stopped, and the output to the electromagnetic switching valve 13 is "OFF" (steps S1 and S2). As a result, the electromagnetic switching valve 9
Is in the state shown in FIG. 1, and the pilot conduit 17a,
17b are respectively connected to the pilot pipes 18a and 18b, the pilot pipe 19a and the pilot pipe 19b are connected to each other, and the pilot operating portions 3 on both sides of the flow control valve 3 are connected.
Since the pressures a and 3b become equal, the flow control valve 3 is maintained in the neutral state as shown in FIG. 1, and the second boom 7 does not operate. Further, since the pilot pressure from the operating lever device 105 is not generated, the flow control valve 2 is also in the state shown in FIG. 1, and therefore the first boom 6 does not move.

Here, when the operator operates the operation lever 10 to the A side in FIG. 1, first, the pressure reducing valve 11a outputs the pilot pressure to the pilot conduit 17a. As a result, the output Pa of the pressure switch 16a is turned "ON", and therefore the signal generator 12 first determines that the state of the operation lever 10 is "up" (step S1). Next, it is determined from the output θ1 of the potentiometer 14 whether the hydraulic cylinder 4 is the longest, that is, whether the stroke end on the extension side has been reached (hereinafter referred to as determination 1) (step S3). At present, the hydraulic cylinder 4 has not reached the stroke end, so the result is "NO". Therefore, next, it is determined from the output θ2 of the potentiometer 15 whether the angle between the first boom 6 and the second boom 7 is smaller than a predetermined angle (hereinafter, referred to as determination 2) (step S4). Since the second boom has not moved yet, this angle has not changed and remains at the predetermined angle (θ2 = θ0). As a result, the determination 2 becomes "NO" and its output becomes "OFF" (step S5). Therefore, the electromagnetic switching valve 13 does not operate, the pilot pipe line 17a remains connected to the pilot pipe line 18a, and the flow rate control valve 2 receives the pilot pressure in the right pilot operating portion 2a and moves to the left in the drawing. As a result, the pressure oil from the hydraulic pump 1 is guided to the bottom side of the hydraulic cylinder 4, and the hydraulic cylinder 4
As a result, the first boom 6 moves upward. Further, at this time, the pilot conduit 19a and the pilot conduit 19b remain connected, and the second boom does not move. As a result, in this situation, only the first boom 6 is operated upward by the operation lever 10.

In this state, when the first boom 6 moves upward and the hydraulic cylinder 4 reaches the stroke end, the judgment 1 becomes "YES" by the output .theta.1 of the potentiometer 14 in the signal generator 12. Therefore (step S3), the signal generator 12 outputs a signal "ON" to the electromagnetic switching valve 13 (step S6). As a result, the solenoid operated directional control valve 13 moves to the left, and the pilot line 17a
Pilot pressure is guided to the pilot operating portion 3a on the right side of the flow control valve 3, and the flow control 3 moves to the left. Therefore, the pressure oil of the hydraulic pump 1 is guided to the bottom side of the hydraulic cylinder 5, and the hydraulic cylinder 5 extends to move the second boom 7 upward. At this time, the pilot pipe line 18a and the pilot pipe line 18b are connected, the pilot operating parts 2a and 2b on both sides of the flow control valve 2 are at equal pressure, the flow control valve 2 is in a neutral state, and the hydraulic pump 1 to the hydraulic cylinder 4 are connected. The supply of pressure oil to the is cut off. Therefore, in this state, only the second boom 7 is operated upward by the operation lever 10.

When the operation of the operating lever 10 is stopped when the hydraulic cylinder 5 reaches the stroke end, the pilot pressure from the pressure reducing valve 11a is lost, and the electromagnetic switching valve 13 and the flow control valve 3 are in the initial state. Second boom 7
Also stops.

Next, when the operating lever 10 is operated to the B side from this state, the pressure reducing valve 11b outputs the pilot pressure to the pilot conduit 17b. As a result, the output Pb of the pressure switch 16b becomes "ON",
In the signal generator 12, first, the state of the operating lever 10 is determined to be "down" (step S1). Next, with the output θ1 of the potentiometer 14, the hydraulic cylinder 4
Is the shortest, that is, whether the stroke end on the contraction side has been reached (hereinafter, referred to as decision 3) (step S7). At present, since the hydraulic cylinder 4 has not reached the stroke end yet, this result is "NO".
Therefore, next, it is determined whether the angle between the first boom 6 and the second boom 7 is larger than a predetermined angle by the output θ2 of the potentiometer 15 (hereinafter, referred to as determination 4) (step S).
8). In this state, the angle is larger than the predetermined angle (θ2> θ because the second boom 7 has moved upward from the initial state).
0). Therefore, judgment 4 is "YES",
The output of the signal generator 12 is "ON" (step S
9). Therefore, the electromagnetic switching valve 13 moves to the left, the pilot pipe line 17b is connected to the pilot pipe line 19a, and the pilot pipe line 18a and the pilot pipe line 18b are connected. As a result, the pilot pressure in the pilot conduit 17b is guided to the pilot operating portion 3b on the left side of the flow control valve 3, so that the flow control valve 3 moves to the right, and the flow control valve 2 moves on both sides of the pilot operating portion 2a. Since 2b has a constant pressure, it is in a neutral state. As a result, the pressure oil from the hydraulic pump 1 is guided to the rod side of the hydraulic cylinder 5, so that the hydraulic cylinder 5 contracts and the second boom 7 moves downward. At this time, the supply of pressure oil to the hydraulic cylinder 4 is cut off, so that the first boom 6 does not move. As a result, in this situation, only the second boom 7 is operated downward by the operation lever 10.

In this way, when the second boom 7 gradually moves downward, the output θ2 of the potentiometer 15 becomes smaller and finally becomes the same as the predetermined value (θ2 = θ0). Then, the determination 4 in the signal generator 12 is “NO”.
Next (step S4), the output of the signal generator 12 becomes "O".
FF ”(step S10). Therefore, the electromagnetic switching valve 13 returns to its original position, the pilot pipe line 17b is connected to the pilot pipe line 18b, the flow control valve 2 moves to the right, and the flow control valve 3 moves to the pilot operating parts 3a on both sides.
Since 3b has a constant pressure, it is in a neutral state. Therefore, the supply of pressure oil from the hydraulic pump 1 to the hydraulic cylinder 5 is cut off, and conversely, the pressure oil of the hydraulic pump 1 is sent to the rod side of the cylinder 4. As a result, the second boom 7
Stops and the first boom 6 starts to move downward. Thus, thereafter, the first boom 6 is operated by the operation lever 10.
Only will be operated downwards.

In this state, the first boom 6 moves downward, and when the cylinder 4 reaches the stroke end, the potentiometer 1 in the signal generator 12 is reached.
Since the determination 3 becomes “YES” by the output θ1 of 4 (step S7), the signal generator 12 outputs the signal “ON” to the electromagnetic switching valve 13 (step S9). As a result, the electromagnetic switching valve 13 moves to the left, the pilot pressure in the conduit 17b is guided to the left side of the flow control valve 3, and the flow control valve 3 moves to the right. Therefore, the pressure oil of the hydraulic pump 1 is guided to the rod side of the hydraulic cylinder 5, and the hydraulic cylinder 5 contracts to move the second boom 7 downward. At this time, the pilot pipe line 18a and the pilot pipe line 18b are connected, the pilot operating parts 2a and 2b on both sides of the flow control valve 2 are at equal pressure, the flow control valve 2 is in a neutral state, and the hydraulic pump 1 to the hydraulic cylinder 4 are connected. The supply of pressure oil to the is cut off. Therefore, in this state, the operation lever 10 is used to move the second boom 7
Only will be operated downwards.

When the operation of the operating lever 10 is stopped when the hydraulic cylinder 5 reaches the stroke end, the pilot pressure from the pressure reducing valve 11a disappears, and the electromagnetic switching valve 13 and the flow control valve 3 are in the initial state. Second boom 7
Also stops.

When the operator again operates the operating lever 10 to the A side in FIG. 1 from this state, the pressure reducing valve 11a outputs the pilot pressure to the pilot conduit 17a. As a result, the output Pa of the pressure switch 16a is turned "ON". Therefore, in the signal generator 12, first, the operation lever 1
It is determined that the state of 0 is “up” (step S
1). Next, the determination 1 is performed based on the output θ1 of the potentiometer 14 (step S3). At present, the hydraulic cylinder 4 has not reached the stroke end, so the result is "NO". For this reason, the potentiometer 15
The determination 2 is performed based on the output θ2 of (step S4).
In this state, the angle is smaller than the predetermined angle (θ2 <θ0) because the second boom 7 has moved downward from the initial state. Therefore, the determination 2 becomes "YES", and the output of the signal generator 12 becomes "ON" (step S6). Therefore, the electromagnetic switching valve 13 moves to the left, the pilot pressure in the pilot conduit 17a is guided to the pilot operating portion 3b on the left side of the flow control valve 3, and the flow control valve 3 moves to the right. As a result, the pressure oil from the hydraulic pump 1 is guided to the bottom side of the hydraulic cylinder 5, and the second cylinder 7 moves upward as the hydraulic cylinder 5 extends. At this time, the pilot line 18a and the pilot line 18b are connected,
The flow rate control valve 2 is in a neutral state because the pilot operating parts 2a and 2b on both sides have a constant pressure, and the supply of pressure oil from the hydraulic pump 1 to the hydraulic cylinder 4 is cut off. Therefore, in this state, only the second boom 7 is operated upward by the operation lever 10.

Then, in this state, the second boom 7 moves upward, and when the angle between the first boom 6 and the second boom 7 reaches a predetermined angle, it returns to the initial state.

As described above, in the present embodiment, the pilot pressure from one operation lever device 105 is distributed to both the first drive device 103 and the second drive device 104, and the pilot pressure is applied from one operation lever device 105. The second boom 7 can also be moved by the pilot pressure of. Therefore, it is possible to operate the first and second booms 6 and 7 with one boom operation lever without providing a new operation lever or an operation device such as a pedal for operating the second boom 7. it can.

While the hydraulic cylinder 4 has not reached the stroke ends on the extension side and the contraction side, the angle between the first boom 6 and the second boom 7 is maintained at a predetermined angle, and the operating lever 10 is operated. Depending on the case, only the first boom 6 is operated. Therefore, by setting the predetermined angle at this time to be the same as the bending angle of the boom in the conventional monoboom hydraulic excavator, the work can be performed without changing the operational feeling of the conventional monoboom hydraulic excavator.

When the hydraulic cylinder 4 reaches the stroke end, the second boom 7 is moved by the same operating lever 10.
By moving only the chisel, the working range can be expanded further upward or downward.

As described above, according to this embodiment, the original performance of the two-piece boom can be sufficiently brought out without impairing the safety, and the workability can be improved.

[0036]

According to the present invention, the operator does not need to stop the operation of the other pedal or the operating lever to operate the second boom, and the first and the first operating levers for one boom are used. Since you can operate the two booms, you can work smoothly and easily. In addition, a wide work range can be secured by operating the second boom with the operation lever. As a result, the original performance of the two-piece boom can be fully brought out without impairing safety, and workability can be improved.

Further, it is possible to operate the second boom with the same operation feeling as a conventional hydraulic excavator, without providing a new operation device such as an operation lever or a pedal for operating the second boom.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a two-piece boom hydraulic excavator according to an embodiment of the present invention.

FIG. 2 is a functional block diagram showing processing contents of the signal generator shown in FIG.

FIG. 3 is a flowchart showing processing contents in an output determination unit of the signal generator shown in FIG.

[Explanation of symbols]

1 Hydraulic Pump 2, 3 Flow Control Valve 4, 5 Hydraulic Cylinder 6 1st Boom 7 2nd Boom 8 Arm 9 Bucket 10 Operating Lever 11a, 11b Pressure Reducing Valve 12 Signal Generator 13 Electromagnetic Switching Valve 14, 15 Potentiometer 16a, 16b Pressure Switches 17a, 17b, 18a, 18b, 19a, 19b Pilot pipeline 100 Upper revolving structure 101 Two-piece boom 102 Front working device 103 First drive device 104 Second drive device 105 Operation lever device

Claims (5)

[Claims] 1. A multi-joint including a two-piece boom including a first boom rotatably attached to an upper revolving structure in a vertical direction and a second boom rotatably attached to the first boom in a vertical direction. Type front working device, and the first
A two-piece boom-type construction work machine comprising: a first drive device that drives a boom; a second drive device that drives the second boom; and an operation lever device that directs driving of the two-piece boom. A first boom detecting means for detecting a position of one boom; a second boom detecting means for detecting a positional relationship between the first boom and a second boom; and an operation detecting means for detecting an operation state of the operation lever device. A signal switching means for allocating a signal from the operating lever device to one of the first and second drive devices based on signals from the first boom detecting means, the second boom detecting means, and the operation detecting means. A two-piece boom-type construction work machine characterized in that 2. The two-piece boom type construction work machine according to claim 1, wherein the signal switching means inputs signals from the first boom detecting means, the second boom detecting means, and the operation detecting means, The signal generating means for deciding which of the first boom and the second boom is to be driven and outputting a signal according to the decision, and the signal from the signal generating means for inputting the signal from the operation lever device to the first And a signal transmission means for transmitting to either of the second drive device and the second drive device, and a two-piece boom type construction work machine. 3. The two-piece boom type construction work machine according to claim 2, wherein the signal transmission means includes an electromagnetic switching valve. 4. The two-piece boom type construction work machine according to claim 1, wherein the signal switching means determines whether the operation is to raise or lower the two-piece boom according to a signal from the operation detecting means. Then, it is determined whether the first boom has reached the maximum raised position or the maximum lowered position by the signal from the first boom detecting means, and the first boom and the second boom by the signal from the second boom detecting means. It is determined whether the angle between the boom and the boom is larger or smaller than a predetermined angle, and the first operation is performed by raising the two-piece boom.
When the angle between the second boom and the second boom is less than or equal to a predetermined angle, the second boom is raised until the predetermined angle is reached, and then the first boom
When the boom is raised and the first boom reaches the maximum raised position, a signal is distributed to the first and second drive means so as to further raise the second boom, and the first and second booms are operated by lowering the two-piece boom. When the angle between them is equal to or greater than a predetermined angle, the second boom is lowered until the predetermined angle is reached, and then the first boom is lowered, and when the first boom reaches the minimum lowered position, the second boom is further lowered. A two-piece boom type construction work machine, characterized in that signals are distributed to the first and second driving means. 5. The two-piece boom construction work machine according to claim 4, wherein the predetermined angle between the first and second booms is set to be substantially the same as the bending angle of the monoboom. Peace boom type construction work machine.