JPH11303120A - Working device for construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently excavate the earth and sand accumulated below a buried article such as an existing pipe. SOLUTION: A second arm 18 is fitted so as to be turnable in the lateral directions to the end of a first arm 12 vertically, turnably fitted to a boom 8, and the first arm 12 and the second arm 18 are connected by a tilting cylinder 28. By expanding or contracting the rod 28B of the tilting cylinder 28, the second arm 18 is turned in the lateral direction with regard to the first arm 12. Thereby, even when the surroundings of an existing pipe B buried under a road of, for instance, narrow width are excavated, the earth and sand accumulated beneath the existing pipe B can be excavated by turning a bucket 25 with the end of the second arm 18 in the state the second arm 18 is tilted laterally with regard to the first arm 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a working device for a construction machine that is used for a construction machine such as a hydraulic excavator and performs an excavation operation for earth and sand.

[0002]

2. Description of the Related Art A hydraulic excavator preferably used for excavation work such as earth and sand usually includes a lower traveling body and an upper revolving body which is pivotably mounted on the lower traveling body. Is provided so as to be able to move up and down. The working device typically includes a boom rotatably provided on the upper revolving unit, an arm rotatably provided on the tip side of the boom, and a bucket rotatably provided on the tip side of the arm. And excavation of earth and sand is performed by rotating the boom, the arm, and the bucket.

[0003] When repairing existing pipes such as water pipes and gas pipes buried in the ground, for example, the existing pipes to be repaired are exposed from the ground.
Sediment accumulated around the existing pipes must be excavated by hydraulic excavators.

[0004] In the hydraulic excavator according to the prior art, the boom, the arm and the bucket constituting the working device are connected in a straight line. For example, when an existing pipe is buried under a narrow road, for example, In addition, it is necessary to perform excavation work in a state where the working device is arranged in parallel with the longitudinal direction of the existing pipe. For this reason, although the sediment deposited above and on the side of the existing pipe can be excavated, it becomes difficult to excavate the soil deposited below the existing pipe.

On the other hand, as another conventional technique, for example, Japanese Unexamined Utility Model Publication No. Hei 5-42339 discloses an arm connecting portion provided at the tip end of the arm so as to be rotatable upward and downward, and an arm connecting portion. A bucket support portion rotatably mounted on the tip end side in a left and right direction, a bucket rotatably provided on the bucket support portion in an up and down direction, and a bucket support portion for rotating the bucket. A provided drilling cylinder,
There has been proposed a hydraulic shovel including a connecting rod for connecting an arm connecting portion and a bucket supporting portion.

In the above-mentioned other conventional hydraulic excavator, the bucket can be tilted left and right with respect to the arm by connecting the arm connecting portion and the bucket supporting portion with the connecting rod. Even when excavation work is performed with the boom and arm arranged parallel to the longitudinal direction of the existing pipe, the bucket inclined to the left and right directions with respect to the arm is inserted below the existing pipe. It is configured to excavate the sediment deposited under the sea.

[0007]

However, in the above-mentioned other conventional hydraulic excavator, since the bucket is inclined leftward and rightward with respect to the arm, the bucket cylinder attached to the arm expands and contracts. The bucket cannot be driven directly by the operation. For this reason,
In this conventional technique, a digging cylinder is separately provided between a bucket supporting portion and a bucket. For this reason, a drilling cylinder is required in addition to the original bucket cylinder for rotating the arm connecting portion, which leads to an increase in the number of parts, a complicated configuration, and a significant increase in the manufacturing cost of the entire working device. is there.

[0008] Further, in the above-mentioned other conventional hydraulic excavator, the excavating cylinder for driving the bucket is directly connected to the bucket without the intervention of a link mechanism or the like. For this reason, there is a problem in that the rotation range of the bucket is smaller than when the link mechanism is provided, and the efficiency of excavation work using the bucket is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, and has as its object to provide a working device of a construction machine capable of efficiently excavating earth and sand deposited below a buried object such as an existing pipe. And

[0010]

In order to solve the above-mentioned problems, a working device of a construction machine according to the invention of claim 1 comprises:
A boom provided on the construction machine main body so as to be rotatable upward and downward, a first arm provided on the distal end side of the boom so as to be rotatable upward and downward, and a boom provided on the distal end side of the first arm; left,
A second arm rotatably provided in the right direction;
A work tool rotatably provided via a link mechanism at the distal end of the arm, and provided between the first arm and the second arm, and the second arm is moved left and right with respect to the first arm And a second arm rotating means for rotating the arm.

With this configuration, the second arm rotating means rotates the second arm left and right with respect to the first arm, and tilts the second arm with respect to the first arm. Can be held. Therefore, for example, at the time of excavation work, the working tool provided on the distal end side of the second arm can be inserted below the existing pipe, and the earth and sand deposited below the existing pipe can be excavated. Further, since the working tool is provided on the distal end side of the second arm via the link mechanism, the turning range of the working tool can be increased, and the excavation work can be performed efficiently.

Further, the invention according to claim 2 is characterized in that the second arm is provided with a working tool cylinder connected to a link mechanism for driving the working tool.

With this configuration, even if the second arm is rotated with respect to the first arm, the work tool cylinder is provided on the second arm together with the work tool.
The work implement can be rotated by the work implement cylinder.

Further, the invention of claim 3 is that the second arm rotating means is constituted by a hydraulic cylinder.

With this configuration, the second arm moves left and right with respect to the first arm in accordance with the expansion and contraction of the hydraulic cylinder.
Since the arm rotates rightward, the inclination of the second arm with respect to the first arm can be adjusted by the expansion and contraction of the hydraulic cylinder.

Further, the invention of claim 4 is that the second arm rotating means is constituted by a rod connecting between the first arm and the second arm.

With this configuration, the first arm and the second arm are connected only by the rod, and the second arm is rotated left and right with respect to the first arm. The inclination of the second arm with respect to the arm can be adjusted.

Further, the invention according to claim 5 is characterized in that the second arm rotating means is constituted by a telescopic rod connecting the first arm and the second arm and having a variable axial length. is there.

With this configuration, the inclination of the second arm with respect to the first arm can be adjusted only by changing the length of the telescopic rod in the axial direction.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment in which a working device of a construction machine according to an embodiment of the present invention is applied to a hydraulic shovel will be described in detail with reference to FIGS.

First, FIGS. 1 to 6 relate to a first embodiment. In FIG. 1, reference numeral 1 denotes a tracked lower traveling body, and 2 denotes a construction machine mounted on the lower traveling body 1 so as to be pivotable. The upper swing body as a main body is shown. And the upper revolving superstructure 2
A cab 4 that is disposed on the turning frame 3 at the front left side and forms an operator's cab; and a cab 4 that is provided on the turning frame 3 and is located at the rear side of the cab 4. It comprises a building cover 5 forming a machine room for accommodating (not shown) and the like, and a counterweight 6 provided on the revolving frame 3 at the rear side of the building cover 5.

Reference numeral 7 denotes a working device provided at the front center of the upper swing body 2 so as to be able to move upward and downward. The working device 7 includes a boom 8, a first arm 12, a second arm 18, a bucket 25, and a tilt, which will be described later. It is composed of a cylinder 28 and the like, and performs excavation work of earth and sand.

Reference numeral 8 denotes a boom whose base end is provided on the front side of the revolving frame 3 so as to be able to move upward and downward. It works. A base end of an arm cylinder 10 for driving the first arm 12 is rotatably provided via a bracket 11 on the upper surface of the boom 8.

Reference numeral 12 denotes a first arm provided at the tip end of the boom 8 so as to be rotatable upward and downward.
As shown in FIGS. 2 and 3, the arm body 13 has a box shape having a rectangular cross section. A pair of upper and lower connecting plates 14 and 14 are fixed to the front end of the arm body 13, and a pin insertion hole 14 </ b> A penetrating upward and downward is formed in the center of each connecting plate 14. ing. Also,
At the rear end of the arm main body 13, a bracket 15 to which the tip end of the arm cylinder 10 is rotatably connected is provided. At the lower end of the arm body 13 located in the vicinity of the bracket 15, a boom connecting portion 16 to which the tip end of the boom 8 is rotatably connected is provided. Further, brackets 17, 17 to which the tilt cylinder 28 is attached are provided on the left and right side surfaces of the arm body 13 so as to protrude at symmetrically left and right positions.

Reference numeral 18 denotes a second arm provided at the distal end of the first arm 12 so as to be rotatable left and right.
8 has an arm main body 19 formed in a box shape having a rectangular cross section, as shown in FIGS. The connecting plate 1 of the first arm 12 is provided at the rear end of the arm body 19.
The connector 20 inserted between the four is fixed, and a pin insertion hole 20A penetrating upward and downward is formed in the center of the connector 20. Brackets 21 and 21 are provided on left and right side surfaces of the arm body 19 so as to project left and right symmetrically, and a tilt cylinder 28 is mounted between each bracket 21 and each bracket 17 of the first arm 12. Configuration. Further, on the upper surface of the arm body 19, a bracket 2 for attaching a bucket cylinder 27 described later is provided.
2 are protruding.

Then, with the connector 20 of the second arm 18 inserted between the connector plates 14 of the first arm 12, the pin insertion hole 14A of each connector plate 14 and the pin insertion hole 20A of the connector 20 are inserted. By inserting the connecting pin 23 and stopping the connecting pin 23 with the retaining ring 24 in the axial direction,
The second arm 18 is connected to the first arm 12 so as to be rotatable left and right.

Reference numeral 25 denotes a bucket as a working tool rotatably provided at the distal end of the second arm 18. The bucket 25 is connected to a bucket cylinder 27 via a link mechanism 26.
Of the bucket cylinder 27B.
As a result, the second arm 18 pivots upward and downward on the distal end side,
Excavation work of earth and sand is performed.

Reference numeral 27 denotes a bucket cylinder as a working tool cylinder provided on the second arm 18. The bucket cylinder 27 includes a tube 27A and a piston (not shown) slidably inserted into the tube 27A. The base end is fixed to the piston, and the tip end is a rod 27B protruding outside from the tube 27A. The bucket cylinder 27 has a proximal end side of the tube 27A rotatably attached to a bracket 22 provided on the upper surface of the arm body 19, and a distal end side of the rod 27B having a link mechanism 26.
Is mounted to be rotatable.

Reference numeral 28 denotes a tilt cylinder provided as a second arm rotating means provided between the first arm 12 and the second arm 18. The tilt cylinder 28 is a tube 28A.
And a piston (not shown) slidably inserted into the tube 28A, and a rod 28B having a proximal end fixed to the piston and a distal end protruding outside from the tube 28A. The tilt cylinder 28 is rotatably mounted on a bracket 17 provided on the left side surface of the first arm 12 with the base end side of the tube 28A.
B is pivotally attached to the bracket 21 provided on the left side surface of the second arm 18 so that the first
The arm 12 and the second arm 18 are connected.

Therefore, the rod 28 of the tilt cylinder 28
By expanding and contracting B, the second arm 18 is rotated leftward and rightward about the connecting pin 23 on the distal end side of the first arm 12, for example, from the position shown by the solid line in FIG. The second arm 18 can be tilted with respect to the first arm 12 within a range up to the position indicated by.

Here, in the present embodiment, the tilt cylinder 28 is provided on the left side of the first arm 12 and the second arm 18, but the tilt cylinder 28 is provided on the right side of the first arm 12. May be disposed between the bracket 17 provided and the bracket 21 provided on the right side surface of the second arm 18, so that the position at which the tilt cylinder 28 is disposed can be selected according to the work content.

The working device 7 of the hydraulic shovel according to the present embodiment has the above-described configuration. Hereinafter, a digging operation for digging around an existing pipe buried underground using the working device 7 will be described. I do.

First, as shown in FIG.
And the first arm 12 are held in a linearly continuous state. For example, as shown in FIG. 1, the working device 7 is arranged in parallel with the existing pipe B buried underground A.

The first operation is performed by the arm cylinder 10.
While rotating the arm 12 and the second arm 18 on the tip side of the boom 8, the bucket cylinder 27
By rotating 5, the earth and sand deposited around the existing pipe B is excavated. In this case, the first arm 12 and the second arm 12
In a state where the arm 18 and the arm 18 are linearly connected, unexcavated earth and sand remains below the existing pipe B.

Then, by operating the tilt cylinder 28 to extend the rod 28B, the second arm 18
Is rotated with respect to the first arm 12, and the second arm 18 is tilted rightward on the distal end side of the first arm 12 as shown by a solid line in FIG. 5. By rotating the bucket 25 by the bucket cylinder 27 in this state, the earth and sand remaining below the existing pipe B can be easily excavated.

When the rod 28B of the tilt cylinder 28 is reduced, for example, the second arm 18 may be tilted to the left on the distal end side of the first arm 12 as shown by a two-dot chain line in FIG. By rotating the bucket 25 by the bucket cylinder 27 in this state,
The excavation range in the left and right directions can be increased.

Here, according to the working device 7 according to the present embodiment, not only is it suitably used for excavating around the existing pipe B buried underground, but also as shown in FIG. Ditching work can also be performed.

That is, by tilting the second arm 18 to the right with respect to the first arm 12 while the hydraulic excavator is arranged obliquely with respect to the road C, the second arm 18 is substantially parallel to the road C. By rotating the bucket 25 with the bucket cylinder 27 while maintaining the above condition, the side groove D can be excavated along the road C.

Thus, according to the present embodiment, the second arm 18 is moved leftward and rightward on the distal end side of the first arm 12 provided rotatably upward and downward on the distal end side of the boom 8. Since the second arm 18 is pivotably connected to the first arm 12 and rotated left and right with respect to the first arm 12 by the tilt cylinder 28, for example, around the existing pipe B buried under a narrow road. Work equipment 7
When the excavation work is performed in a state in which the second arm 18 is arranged in parallel with the longitudinal direction of the existing pipe B, the second arm 18 is tilted left and right with respect to the first arm 12 so that the pile is deposited below the existing pipe B. Excavated earth and sand can be easily excavated.

Moreover, the first arm 12 and the second arm 18
Is connected by a tilt cylinder 28, so that the rod 28B of the tilt cylinder 28 is extended and contracted, so that the second arm 18 with respect to the first arm 12 is extended.
Can be properly adjusted in the left and right directions. For this reason, for example, when excavating earth and sand deposited above and on the side of the existing pipe B buried underground, the second arm 1
When the bucket 25 is rotated in a state where the second arm 18 is linearly arranged with respect to the first arm 12 and the earth and sand deposited below the existing pipe B is excavated, the second arm 18 is moved to the first arm 12.
By rotating the bucket 25 in a state where the bucket 25 is inclined with respect to, the earth and sand deposited around the existing pipe B can be efficiently excavated.

Also, since the bucket cylinder 27 is provided on the second arm 18 and the distal end of the bucket cylinder 27 is connected to the link mechanism 26, the second arm 18
Is tilted with respect to the first arm 12, the bucket 25 can be directly driven by the expansion and contraction of the bucket cylinder 27. For this reason, for example, as compared with a configuration in which an excavation cylinder for driving a bucket is separately provided in addition to the bucket cylinder as in the above-described other related art,
The configuration of the entire working device can be simplified, which can contribute to a reduction in manufacturing cost.

Further, the bucket 25 is rotatably provided on the distal end side of the second arm 18 via the link mechanism 26, so that the bucket and the excavating cylinder are directly connected, for example, as in the above-mentioned other prior art. Compared to the configuration
The range of rotation of the bucket 25 can be increased, and excavation work can be performed efficiently.

Next, FIG. 7 shows a second embodiment according to the present invention. In this embodiment, the left arm of the first arm 12 and the left arm of the second arm 18 and the first arm 1
The right side of the second arm 18 and the right side of the second arm 18 are connected by a tilt cylinder. In this embodiment, the same components as those in the above-described first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 7, reference numerals 31 and 31 denote the first arm 1.
Two tilts as second arm rotating means connecting between the left side of the second arm 18 and the left side of the second arm 18 and between the right side of the first arm 12 and the right side of the second arm 18. Cylinders, each tilt cylinder 31 is a tube 31
A, a piston (both not shown) slidably inserted into the tube 31A, and a rod 31B fixed at the base end to the piston and projecting from the tube 31A to the outside at the distal end. And each tilt cylinder 3
The first tube 31A and the piston are formed to have smaller diameters than the tube 28A and the piston of the tilt cylinder 28 applied to the first embodiment.

Here, each tilt cylinder 31 has the base end of the tube 31A rotatably attached to the bracket 17 provided on the left and right side surfaces of the first arm 12, and the tip end of the rod 31B is connected to the second arm. The bracket 18 is rotatably attached to brackets 21 provided on the left and right side surfaces.

Then, the rod 31B of the left tilt cylinder 31 is extended, and the right tilt cylinder 3 is extended.
By reducing the size of one rod 31B, the second arm 18 rotates to the right with respect to the first arm 12, and the rod 31B of the right tilt cylinder 31 is extended,
By reducing the rod 31B of the left tilt cylinder 31, the second arm 18 is configured to rotate leftward with respect to the first arm 12.

The working device according to the present embodiment has the above-described configuration, and there is no particular difference in the basic operation from the working device according to the above-described first embodiment.

According to the present embodiment, the left and right side surfaces of the first arm 12 and the second arm 18 are connected by the tilt cylinders 31, 31, and one of the tilt cylinders 3 is used.
By extending the other tilt cylinder 31 when the first tilt cylinder 31 is contracted and extending the other tilt cylinder 31 when the one tilt cylinder 31 is contracted, the second arm 18 is moved to the first arm.
Since it is configured to rotate left and right with respect to the arm 12, each tilt cylinder 31 can be downsized.
Workability at the time of excavation in a small work site can be improved.

Next, FIG. 8 shows a third embodiment of the present invention. In this embodiment, the axial length between the first arm 12 and the second arm 18 is variable. They are connected by telescopic rods. In this embodiment, the same components as those in the above-described first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 8, reference numeral 41 denotes a telescopic rod as a second arm rotating means connecting between the left side of the first arm 12 and the left side of the second arm 18, and this telescopic rod 41 is an inner rod. An elongated cylindrical body 41 having a screw hole formed on the peripheral side
A, and a threaded rod 41 which is screwed into a screw hole of the cylindrical body 41A and whose protruding length from the cylindrical body 41A changes according to the amount of screwing.
B. Here, the proximal end of the cylindrical body 41A is rotatably attached to the bracket 17 of the first arm 12, and the distal end of the threaded rod 41B is rotatably attached to the bracket 21 of the second arm 18. .

The telescopic rod 41 is inserted into the threaded hole of the cylindrical body 41A by an operator or the like while the distal end of the threaded rod 41B is detached from the bracket 21 of the second arm 18. After adjusting the protrusion length of the threaded rod 41B from the cylindrical body 41A,
1B is attached to the bracket 21 of the second arm 18 so that the second arm 1
The configuration is such that the left and right tilts of 8 can be adjusted appropriately.

The working device according to the present embodiment has the above-described configuration, and there is no particular difference in the basic operation from the working device according to the above-described first embodiment.

According to the present embodiment, however, the protrusion length between the first arm 12 and the second arm 18 changes according to the cylindrical body 41A and the amount of screwing into the screw hole of the cylindrical body 41A. The structure of the second arm rotating means is simpler than the case where the tilt cylinder 28 (31) according to each of the above-described embodiments is used, since the structure is connected by the telescopic rod 41 including the threaded rod 41B. It can contribute to reduction of manufacturing cost.

In each of the above-described embodiments, the tilt arm 28 (31) having a variable length in the axial direction is used as the second arm rotating means for connecting the first arm 12 and the second arm 18 to each other. Although the case where the telescopic rod 41 is used has been described as an example, the present invention is not limited to this. For example, as shown in a modification shown in FIG. Using the rod 51, the connecting rod 5
1 is connected to the bracket 17 of the first arm 12 and the bracket 21 of the second arm 18 so that the first
The second arm 18 may be rotated left and right with respect to the arm 12.

In the third embodiment, as the second arm rotating means for connecting the first arm 12 and the second arm 18, a cylinder 41A having a screw hole, an operator or the like is used. The hand-operated telescopic rod 41 including the threaded rod 41B screwed into the threaded hole of the cylindrical body 41A is used, but the present invention is not limited to this.
A telescopic rod having a motor or the like for driving B may be used.

Further, in each of the above-described embodiments, the working device provided with a bucket for excavating earth and sand or the like as a working tool has been described as an example. However, the present invention is not limited to this. Cutter, tamper for consolidation work,
The present invention can also be applied to a working device provided with another working tool such as an earth drill for drilling work.

[0057]

As described above in detail, according to the first aspect of the present invention, the first arm is provided on the tip side of the boom so as to be rotatable upward and downward, and the second arm is provided on the tip side of the first arm. Arm left,
A second arm rotating means provided between the first arm and the second arm so as to be rotatable to the right, and the second arm is rotated left and right with respect to the first arm; Therefore, for example, when excavating around an existing pipe or the like buried in the ground, by rotating the second arm by the second arm rotating means, and tilting the second arm with respect to the first arm, The working tool provided on the distal end side of the second arm can be inserted below the existing pipe. For this reason, the earth and sand deposited below the existing pipe can be easily excavated by the working tool while avoiding interference with the existing pipe. Moreover, since the working tool is provided on the distal end side of the second arm via the link mechanism, the range of rotation of the working tool can be increased by the link mechanism, and excavation work and the like can be performed efficiently.

According to the second aspect of the present invention, since the second arm is provided with the work tool cylinder connected to the link mechanism for driving the work tool, the second arm is connected to the first arm. Even if the work implement is tilted, the work implement can be smoothly rotated on the distal end side of the second arm by rotating the link mechanism by the work implement cylinder. Therefore, for example, there is no need to separately provide a cylinder for driving the bucket in addition to the bucket cylinder, and the configuration can be simplified.

Further, according to the third aspect of the present invention, since the second arm rotating means is constituted by a hydraulic cylinder, the hydraulic cylinder is operated to rotate the second arm, so that the second arm is rotated in accordance with the work content. The inclination of the second arm with respect to one arm can be appropriately adjusted, and workability when performing excavation work or the like can be improved.

According to the fourth aspect of the present invention, the second arm rotating means is constituted by the rod connecting the first arm and the second arm. The second arm can be tilted left and right with respect to the first arm only by connecting the gaps with the rod.

According to the fifth aspect of the present invention, the second arm rotating means is constituted by a telescopic rod having a variable axial length, which connects the first arm and the second arm. Therefore, the inclination of the second arm with respect to the first arm can be easily adjusted by changing the axial length of the telescopic rod according to the work content.

[Brief description of the drawings]

FIG. 1 is a front view showing a hydraulic excavator provided with a working device according to a first embodiment of the present invention.

FIG. 2 is an enlarged front view showing a first arm, a second arm, a bucket, a tilt cylinder and the like in FIG. 1;

FIG. 3 is a plan view of a first arm, a second arm, a bucket, a tilt cylinder, and the like shown in FIG. 2;

FIG. 4 is a plan view showing a state where a second arm in FIG. 3 rotates with respect to the first arm.

5 is a longitudinal sectional view showing a state in which the periphery of an existing pipe is excavated by tilting a second arm, as viewed from a direction indicated by an arrow VV in FIG. 1;

FIG. 6 is a plan view showing a state in which a side ditch digging operation is performed with the second arm inclined.

FIG. 7 is a plan view similar to FIG. 4, showing a working device according to a second embodiment of the present invention.

FIG. 8 is a plan view similar to FIG. 4, showing a working device according to a third embodiment of the present invention.

FIG. 9 is a plan view similar to FIG. 4, showing a working device according to a modification of the present invention.

[Explanation of symbols]

 2 Upper revolving superstructure (construction machine body) 8 Boom 12 First arm 18 Second arm 25 Bucket (work implement) 26 Link mechanism 27 Bucket cylinder (work implement cylinder) 28, 31 Tilt cylinder (second arm rotating means) 41 Telescopic rod (second arm rotating means) 51 Connecting rod (second arm rotating means)

Claims (5)

[Claims] 1. A boom provided on a construction machine main body so as to be rotatable upward and downward, a first arm provided on a tip side of the boom so as to be rotatable upward and downward, and the first arm. A second arm rotatably provided on the distal end side of the arm in left and right directions, a work implement rotatably provided on a distal end side of the second arm via a link mechanism, and the first arm And a second arm rotating means provided between the first arm and the second arm for rotating the second arm left and right with respect to the first arm. 2. The working device of a construction machine according to claim 1, wherein the second arm is provided with a working tool cylinder connected to the link mechanism to drive the working tool. 3. The construction machine working device according to claim 1, wherein said second arm rotating means is constituted by a hydraulic cylinder. 4. The working device for a construction machine according to claim 1, wherein the second arm rotating means is constituted by a rod connecting the first arm and the second arm. 5. The second arm rotating means comprises a telescopic rod which connects the first arm and the second arm and has a variable axial length.
A working device of a construction machine according to claim 1.