JP3304186B2 - Swing type excavator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swing type excavator capable of swinging a front structure in a horizontal direction, and more particularly to an ultra-small turning type excavator capable of turning within a vehicle width by a swing type.

[0002]

2. Description of the Related Art In recent years, in order to enable work in narrow places,
The upper revolving unit can be turned within almost the vehicle width of the lower traveling unit,
In addition, excavation capable of so-called in-vehicle-width turning, in which a front structure including a bucket, an arm, and a boom can be turned while being held within the vehicle width in a posture in which the front structure is folded above the upper revolving structure (hereinafter referred to as a turning posture). Machine has been developed and is said to be a micro-swing hydraulic excavator. Such an ultra-small turning hydraulic excavator can be oriented in any direction within a circle having a vehicle width as a diameter, so that it can be operated in any narrow place as long as the width allowing the vehicle body to pass can be secured. For example, when performing construction on one lane of a two-lane road, the construction can be performed by stopping traffic on only one lane instead of stopping traffic on both lanes, thereby minimizing traffic regulations.

[0003] In general, a small hydraulic excavator including an ultra-small turning type is required to be able to dig a gutter near the vehicle width without changing the vehicle body position. There is.

The offset method is disclosed in, for example,
As described in JP-A-0427 and JP-A-2-213525, the boom is divided into a lower boom and an upper boom so that the upper boom can swing horizontally with respect to the lower boom, and a lower boom and an arm are provided between the lower boom and the arm. A parallel link mechanism is provided, and a cylinder for driving the parallel link mechanism is provided between the lower boom and the upper boom, and by driving the cylinder, the arm moves parallel to the lower boom by the action of the parallel link mechanism, This makes it possible to dig a groove at a desired position on the inner side of the vehicle width without turning the upper turning body at the time of digging the gutter.

The swing method is disclosed in, for example, Japanese Utility Model Laid-Open No. 4-461.
As disclosed in Japanese Patent Publication No. 49, a swing post capable of swinging in a horizontal direction is provided in the center of the upper revolving structure ahead of the cab, and a front structure is attached to the swing post. By swinging the swing post and swinging the entire front structure in the horizontal direction, the side groove can be dug. However, as a boom provided in this swing type excavator, a mono boom bent at a certain angle is used so that deep excavation can be performed.

Heretofore, an offset type excavator has been put into practical use as an ultra-small turning hydraulic excavator (hereinafter referred to as a first conventional technology). The reason is as follows. The boom is generally bent at a certain angle, and in order to achieve ultra-small turning using such a boom, one end of the boom is supported near the center of the upper swing body in the front-rear direction. There is a need. However, when the swing method is employed in such a manner that the one end side of the boom is supported near the center in the front-rear direction of the upper revolving structure, the front structure is horizontally swung with respect to the upper revolving structure at the time of the gutter excavation work. The boom interferes with the cab, so that the front structure cannot be swung toward the cab. Therefore, in order to avoid interference between the front structure and the driver's cab, an offset system in which the arm can swing in the horizontal direction with respect to the boom has to be adopted.

[0007] The ultra-small swing hydraulic excavator employs the above-described offset method, and further adds a mechanism between the upper boom and the lower boom to swing the upper boom vertically with respect to the lower boom. The boom is movable, and the opening angle between these two booms is changed by using a cross link.
2nd prior art).

[0008]

However, the above prior art has the following problems. First, in the first prior art, since the offset structure is used, it is necessary to provide a complicated parallel link mechanism and a driving cylinder for the front structure, which increases the weight of the front structure. Such a problem arises.

(1) The weight of the front structure becomes extremely heavy, and depending on the posture of the front structure, the position of the center of gravity is biased toward the front end of the front structure, resulting in poor stability.

(2) Since the weight of the front structure is heavy,
The counterweight also needs to be heavy. This allows
The excavator weighs as much as a shovel of one class higher than a standard excavator that does not use the offset method, and the transportation cost increases. Further, the size of the upper-part turning body also becomes large, which is an obstacle to realizing a very small turning.

(3) Since the weight of the machine increases, it is necessary to increase the output of the prime mover, which increases the manufacturing cost and running cost.

Further, the first prior art is an offset method, in which the arm and the bucket are offset in parallel to the boom, so that the following problem occurs.

(4) A vertical pin is used for connection between the lower boom and the upper boom. When the crushing operation is performed by a front attachment such as a breaker that generates a large impact force or vibration in the excavation direction, the vertical pin is used. May bend or break.

(5) When digging a gutter deep, the lower part of the parallel link mechanism may interfere with the ground surface, so that the digging depth cannot be made larger than that of a standard machine not using the offset method.

(6) Due to the complicated parallel link mechanism, the manufacturing cost increases and the maintainability deteriorates.

(7) When the arm and the bucket are offset to the opposite side of the cab, the excavation position is difficult to see from the cab because the boom blocks the view.

(8) If the arm and the bucket are offset to the cab side, the bucket is located in front of the cab and may interfere with the cab, which is dangerous. In order to avoid such a danger, it is necessary to take measures for preventing interference. For this purpose, a detecting means for detecting a lower boom forming a front structure, a turning angle of an arm, and an offset amount. Further, the configuration of the entire interference prevention device including the arithmetic means is complicated, and the manufacturing cost is increased.

Also, in the second prior art, since the same offset system as in the first prior art is adopted,
The same problem as described above occurs.

On the other hand, in the swing type excavator, the foot end of the boom cannot be supported near the center in the front-rear direction of the upper revolving structure as described above, and the entire front structure is accommodated within the vehicle width. A structure capable of turning within the vehicle width could not be obtained. That is, in the swing system, the end of the boom foot side is supported by a swing post installed substantially at the center of the front of the cab, and a monoboom having a constant vertical bending angle is used as the boom. For this reason, if the bending angle of the boom is set so that deep excavation is possible when the boom is lowered at the maximum, a part of the front structure protrudes from the vehicle width even when turning in the boom maximum raising posture. In addition, since the swing post is located in the front center of the cab, in order to increase the swing angle when the boom is raised maximum, the cab must be shifted backward on a narrow upper revolving structure,
It is difficult to design due to the layout of the cab.

A first object of the present invention is to provide a swing type excavator capable of turning inside a vehicle width with a simple configuration without using a complicated link mechanism, that is, without increasing the weight of a front structure so much. To provide.

A second object of the present invention is to provide a swing system capable of turning within the vehicle width with a simple structure and capable of easily avoiding interference between the front structure and the cab when the front structure is swung. Is to provide an excavator.

[0022]

In order to achieve the first and second objects, according to the present invention, there is provided a lower traveling body, an upper revolving body rotatably mounted on the lower traveling body, and an upper revolving body. A front structure including a driver's cab and a bucket, an arm, and a boom mounted on a body, a swing post installed on the upper revolving structure, and a boom of the front structure connected to the swing post, whereby the front In a swing type excavator capable of horizontally swinging the entire structure, the upper revolving unit is sized to be able to turn within substantially the vehicle width of the lower traveling unit, and the boom of the front structure is swung. A lower boom swingable vertically with respect to the post, and an upper boom swingable vertically with respect to the lower boom; An opening angle adjusting means for changing an opening angle of the lower boom and the upper boom in a vertical direction according to a vertical swing angle of the lower boom is provided, and the swing post is forward of the cab of the upper swing body and is installed in the position of the side, said opening angle adjustment means, before
When the front structure is in the maximum reach position
And swing the lower boom upwards to
The lower boom and the above
The vertical opening angle with the upper boom increases, and
When the pre-SL front structure the turning posture, the front structure across the opening of said lower boom and said upper boom depending on the vertical swing angle of the lower boom to fit within pivot circle of the upper rotating body The angle is changed.

In order to achieve the first and second objects, according to the present invention, a lower traveling body, an upper revolving body rotatably mounted on the lower traveling body, and a lower revolving body mounted on the upper revolving body are provided. A driver's cab, a bucket, an arm, and a front structure including a boom, a swing post is installed on the upper swing body, and the boom of the front structure is connected to the swing post, whereby the entire front structure is formed. In a swing type excavator capable of swinging in a horizontal direction, the upper revolving unit is sized to be able to pivot within substantially the vehicle width of the lower traveling unit, and the boom of the front structure is moved relative to the swing post. A lower boom swingable in a vertical direction, and an upper boom swingable in a vertical direction with respect to the lower boom, wherein the lower structure is provided on the front structure. Opening angle adjusting means for changing the opening angle of the lower boom and the upper boom in the vertical direction according to the vertical swing angle of the boom, wherein the swing post is forward of the driver's cab of the upper swing body and is installed in the position of the side, said opening angle adjustment means, the front
Than when the structure is in the maximum reach position.
Swing the front structure by swinging the aboom upward
The lower boom and the upper boo
When the arm is rolled up while swinging the lower boom upward with the front structure swinging toward the cab side when the opening angle in the vertical direction with respect to the cab increases , the bucket Pass through
The opening angle between the lower boom and the upper boom is changed according to the vertical swing angle of the lower boom.

[0024] Preferably, the opening angle adjustment means, the
The swing angle of the lower boom is at least that of the front structure.
In the area larger than the swing angle at the maximum reach position
When the lower boom is swung upward, the opening angle between the lower boom and the upper boom is changed so as to increase.

Preferably, the opening angle adjusting means includes a first swing angle of the lower boom larger than a predetermined swing angle.
When the lower boom is swung upward in the area, the opening angle between the lower boom and the upper boom increases, and in the second area where the lower boom swing angle is smaller than the predetermined swing angle, the lower boom is swung downward. The opening angle between the lower boom and the upper boom increases, and the opening angle is changed so that the opening angle becomes the minimum at the predetermined swing angle.

Preferably, the opening angle adjusting means is set so that the swing angle of the lower boom at the maximum reach position of the front structure substantially matches the predetermined swing angle.

Preferably, the opening angle adjusting means increases the opening angle between the lower boom and the upper boom when the swing angle of the lower boom is near the maximum raising angle of the lower boom than when it is near the maximum lowering angle. The opening angle is changed so as to be as follows.

[0028] Preferably, the connecting point between the lower boom and the swing post is located behind the front structure with respect to the swing center of the swing post.

Preferably, the opening angle adjusting means is provided in at least a part of a swing range of the lower boom.
So as to intersect with respect to a straight line connecting the connection point between the connecting point and the lower boom and the upper boom of the lower boom and the swing post Te, one end of which is connected via a horizontal pin on the swing post, a horizontal pin upper boom is the other end Are cross-links connected via a.

In the above, preferably, the position of the connecting point between the cross link and the swing post is located rearward of the front structure or closer to the front structure than the position of the connecting point between the lower boom and the swing post. .

Preferably, the opening angle adjusting means includes a hydraulic cylinder having one end connected to a swing post or a lower boom via a horizontal pin and the other end connected to an upper boom via a horizontal pin. Means for controlling the expansion and contraction of the hydraulic cylinder so that the opening angle between the lower boom and the upper boom changes according to the swing angle in the direction.

[0032]

According to the present invention, the boom is divided into a lower boom and an upper boom.
The opening angle of the lower boom and the upper boom in the vertical direction according to the swing angle of the lower boom by the opening angle adjusting means (hereinafter, referred to as
By varying the) that boom between aperture angle, changing the boom between angular aperture when trying to pivot posture convolving the front structure raises the lower boom, the upper-handed
The front structure can be accommodated within the turning circle of the rotating body . For this reason, by making the upper revolving structure a size that can be turned within substantially the vehicle width of the lower traveling structure, the upper revolving structure and the entire front structure can be turned within the vehicle width. As described above, a swing method having a simple structure is adopted without using a complicated parallel link mechanism, and an ultra-small turning type excavator capable of turning within the vehicle width is obtained. Further, the front structure is swung toward the cab side by changing the opening angle between the booms according to the swing angle of the lower boom by the opening angle adjusting means .
When the arm is rolled up while swinging the lower boom upward in this state , the bucket can pass above the cab (described later).

Further, since the swing post is installed at a position in front of and at the side of the driver's cab of the upper swing body, the lower boom can interfere with the driver's cab without greatly changing the layout such as shifting the driver's cab rearward. The swing angle at the time of raising the boom can be increased without causing the boom to rise. Therefore, when turning within the vehicle width is enabled, the degree of freedom in designing the cab layout of the upper-part turning body increases. When the swing post is installed in front of and in the side of the driver's cab, generally, when the boom is lifted and the arm is involved with the swing post and the front structure swinging at a right angle position on the driver's cab side, Although there is a concern that the bucket may hit the cab, the present invention employs an opening angle adjusting means for increasing the opening angle between the booms when the lower boom is raised. And there is no fear of the bucket hitting the cab.

Further, the opening angle adjusting means is provided with the lower boom.
The swing angle of at least the maximum reach of the front structure
When the swing angle is larger than the swing angle at the position, the swing angle between the booms is increased by swinging the lower boom upward, so that the swing angle between the booms at the lower-boom maximum raising position is increased, and the vehicle width is increased. It is possible to take a narrower turning posture.

Further, the opening angle adjusting means increases the opening angle between the booms when the lower boom swings upward in the first region where the swing angle of the lower boom is larger than the predetermined swing angle. By increasing the opening angle between the booms when the lower boom is swung downward in the second area where the moving angle is smaller than the predetermined swing angle, the opening between the booms at the lower boom maximum raising position in the first area is increased. It is possible to take a turning posture narrower than the vehicle width due to an increase in the angle, and to perform a deep excavation to move the bucket to a deep position by increasing the opening angle between the booms at the lowermost position of the lower boom in the second area. It becomes possible. Further, by minimizing the opening angle at the predetermined swing angle, the swing angle of the lower boom at the maximum reach position of the front structure can be set near this predetermined swing angle, and the maximum reach can be achieved. The opening angle between the booms at the position becomes small, the maximum reach length from the turning center to the tip of the bucket can be shortened, and the overturning moment at the maximum reach position can be reduced to improve the stability.

In particular, by making the swing angle of the lower boom at the maximum reach position of the front structure substantially coincide with the predetermined swing angle at which the opening angle between the booms is minimized, the maximum reach length is minimized, and the stability is improved. The effect of improvement is maximum.

Further, the opening angle adjusting means increases the opening angle between the booms when the swing angle of the lower boom is near the maximum raising angle of the lower boom as compared with when the swing angle of the lower boom is near the maximum lowering angle. It becomes possible to take a turning posture narrower than the vehicle width at the position where the lower boom is raised, and to perform deep digging by moving the bucket to a deep position at the position where the lower boom is lowered.

Further, the connecting point between the lower boom and the swing post is located behind the front structure with respect to the swing center of the swing post, so that the lower boom, that is, the vertical direction of the front structure, Swing center can be brought closer. Accordingly, the minimum turning radius can be further reduced, and the amount of increase in the opening angle between the booms required to accommodate the front structure within the vehicle width is reduced, thereby reducing the load on the opening angle adjusting means. It becomes possible. In addition, by bringing the swing center of the front structure closer to the center of rotation of the upper revolving structure, the maximum reach length from the center of rotation to the tip of the bucket can be shortened. It is possible to improve the performance. On the other hand, since the swing center of the swing post does not change, the distance of the side groove (the distance from the outer side surface of the lower traveling structure to the outer side surface of the side groove) is not sacrificed.

Further, the opening angle adjusting means is a cross link having one end connected to the swing post via a horizontal pin and the other end connected to the upper boom via a horizontal pin, and the cross link is connected to the lower boom and the swing post. Crossing the straight line connecting the connecting point of the lower boom and the upper boom to the connecting point of the lower boom increases the opening angle between the booms at the maximum raising position of the lower boom, and takes a turning posture narrower than the vehicle width at this position. Becomes possible.

In the above, the position of the connection point between the cross link and the swing post is located behind the position of the connection point between the lower boom and the swing post with respect to the front structure, so that the distance between the booms at the maximum reach position is obtained. The opening angle is reduced, the maximum reach length from the center of rotation to the tip of the bucket can be shortened, and the opening angle between the booms at the lowermost position of the lower boom increases, enabling deep digging.

On the other hand, by setting the position of the connection point between the cross link and the swing post closer to the front structure than the position of the connection point between the lower boom and the swing post, the same operation as described above can be obtained, and The connecting position at one end of the cross link comes before the connecting position of the lower boom on the post, so the length before and after the swing post can be shortened, and the swing post itself can be reduced in size. The degree increases.

The opening angle adjusting means includes a hydraulic cylinder having one end connected to the swing post via a horizontal pin and the other end connected to the upper boom via a horizontal pin.
Means for controlling the expansion and contraction of the hydraulic cylinder so that the opening angle between the lower boom and the upper boom changes according to the vertical swing angle of the lower boom, so that the opening angle between the booms is adjusted according to the swing angle of the lower boom. Can be changed. In this case, the expansion and contraction of the hydraulic cylinder can be changed at an arbitrary ratio, and the opening angle between the booms can be changed at an arbitrary ratio.

In the specification of the present application, "substantially within the vehicle width" means that it is practically sufficient to be within the "vehicle width". Protruding from the end face) is allowed.

[0044]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a swing type excavator according to the present invention will be described with reference to FIGS. The excavator according to the present embodiment is an ultra-small turning hydraulic excavator capable of turning within a vehicle width.

First, the configuration of the excavator of this embodiment will be described. In the excavator according to the present embodiment, as shown in FIGS. 1 and 2, an upper revolving unit 11 is installed on a lower traveling unit 10 that travels and moves an airframe, and A driver's cab 12 is installed, and a swing post 13 is attached to a front and side position of the driver's cab 12 by a swing pin 30 which is a vertical pin, and a bucket 22, an arm 19, an upper boom 17, a lower boom 14, a cross The front structure 1 including the link 15 is attached. The swing post 13 can swing in the horizontal direction about the swing pin 30.
The driver's cab 12 is a canopy type having a roof 12A, and a driver's seat, various operation levers, and the like are installed in the driver's cab 12 as is well known.

The upper revolving unit 11 has a size capable of turning within substantially the vehicle width of the lower traveling unit 10, and can be turned horizontally by a turning mechanism (not shown). Also,
The upper revolving unit 11 includes a boom cylinder 16, an arm cylinder 18, and a bucket cylinder 2, which will be described later, in addition to the above-described cab 12, swing post 13, and front structure 1.
0, all hydraulic equipment such as a hydraulic pump and a valve for driving the swing cylinder 23 and the like, and other equipment necessary for a general hydraulic shovel such as a motor are mounted.

The boom is divided into two parts, a lower boom 14 and an upper boom 17.
The foot end is connected to the swing post 13 by a horizontal pin 31 and the tip is connected to the upper boom 17 by a horizontal pin 32. Also, the boom cylinder 16
Swing post 13 with horizontal pin 16A at bottom end
Then, the rod tip is connected to the lower boom 14 by a horizontal pin 16B, and the lower boom 14 is vertically swung by its expansion and contraction. That is, the boom cylinder 16 is a driving force for swinging the lower boom 14. On the other hand, the upper boom 17 has a bottom end on the lower boom 14 with the horizontal pin 32 as described above and a tip with the horizontal pin 33 on the arm 19 as described above.
, And a cross link 15 described later is connected by a horizontal pin 34.

In the swing post 13, the horizontal pin 31, which is a connection point between the lower boom 14 and the swing post 13, is located behind the swing pin 30, which is the swing center of the swing post 13, with respect to the front structure 1. are doing.

The cross link 15 is a member constituting an opening angle adjusting means. One end of the cross link 15 is connected to the swing post 13 by a horizontal pin 35, and the other end is connected to the upper boom 17 by a horizontal pin 34. In the swing post 13, the horizontal pin 35 at one end of the cross link 15 is located behind the horizontal pin 31 at the end on the foot side of the lower boom 14 with respect to the front structure 1. The cross link 15 in the posture of FIG. A horizontal pin 32 connecting the upper boom 17 and the lower boom 14 intersects a straight line connecting the horizontal pin 31 connecting the lower boom 14 and the swing post 13.

The arm 19 is connected to the distal end of the upper boom 17 by the horizontal pin 33 so as to be swingable in the vertical direction as described above, and the bucket 22 is connected to the distal end of the arm 19 via the bucket link 21. They are connected to be able to swing up and down. Upper boom 17 and arm 19
The arm cylinder 18 is attached between the arm cylinders 18 by horizontal pins 36 and 37, and the angle between the arm 19 and the upper boom 17 changes by the expansion and contraction of the arm cylinder 18.
A bucket cylinder 20 is attached between the arm 19 and the bucket link 21 by horizontal pins 38 and 39, and the bucket link 21 moves by the expansion and contraction of the bucket cylinder 20, and the bucket 22 moves around the connection point of the arm 19. It oscillates and excavates earth and sand. That is, the arm cylinder 18 and the bucket cylinder 20
9 and the bucket 22.

The rod end of the swing cylinder 23 is connected to the swing post 13 by a vertical pin 23a, and the bottom end of the swing cylinder 23 is connected to a predetermined position of the upper swing body 11 by a vertical pin 23b. I have. When the swing cylinder 23 expands and contracts as shown by a broken line in FIG.
3 swings as shown by the broken line, and accordingly, the above-described front structure 1 also swings with respect to the upper swing body 11 (see FIG. 2). When excavating gutters with this excavator,
Similarly to the conventional swing method, the upper swing body 11 is swung, and the swing cylinder 23 is extended and contracted in accordance with the swing swing so that the swing post 13, and thus the front structure 1, swings in the opposite direction to the upper swing body 11. Do.

Next, the operation of the excavator of this embodiment will be described with reference to FIGS. In FIG. 3, the lower boom 14 swings up and down around a horizontal pin 31 which is a connection point with the swing post 13 due to expansion and contraction of the boom cylinder 16. Since the upper boom 17 is connected to the lower boom 14 by a horizontal pin 32 and the cross link 15 is connected to a horizontal pin 34, the upper boom 17 moves in conjunction with the lower boom 14 so that the opening angle changes.

The locus A of the horizontal pin 32 at the tip of the lower boom 14 is a circle (indicated by a dashed line in the drawing) centered on the horizontal pin 31 at the foot end of the lower boom 14, and the horizontal pin 34 at the tip of the cross link 15 is formed. The trajectory B is a circle (shown by a two-dot chain line in the figure) centered on the horizontal pin 35 at one end of the cross link. The locus C of the horizontal pin 33 connecting the upper boom 17 and the arm 19 is shown in the figure for reference. In the posture of FIG. 1, the cross link 15 is
2 and the horizontal pin 31 are connected so as to intersect with a straight line connecting the horizontal pin 31 and the horizontal pin 32 at the distal end of the lower boom 14 and the horizontal pin 34 at the distal end of the cross link 15 are set so as to overlap as shown in FIG. I have. Here, cross link 1
Locus if the locus B of the horizontal pin 34 of the 5 tip lies outside the trajectory A of the horizontal pin 32 of the lower boom 14 tip
As the difference between A and B increases, the opening angle between the booms increases. On the contrary, when the locus B of the horizontal pin 34 is inside the locus A of the horizontal pin 32 , the difference between the locus A and B becomes smaller.
As the size increases, the opening angle between the booms decreases.
By setting the positions of the cross link 15 and the lower boom 14, desired control of the opening angle between the booms becomes possible.

That is, when the swing angle of the lower boom 14 is in the first region (indicated by I in the drawing) including the angle at the time of the maximum raising, as the lower boom 14 is swung upward, the opening angle between the booms becomes When the swing angle of the lower boom 14 is in the second region (indicated by II in the figure) including the angle at the time of the maximum lowering, the lower boom 14 is swung downward, and the opening angle between the booms becomes larger. When the swing angle of the lower boom 14 is a predetermined angle φ at the boundary between the first region and the second region, the opening angle between the booms is minimized. In FIG. 3, the swing angle of the lower boom 14 at the time of the maximum reach of the front structure 1 is around the predetermined angle φ.

In FIG. 3, the opening angle between the booms in the turning posture is α, the opening angle between the booms at the maximum reach position where the front structure is extended most to the ground, and the opening angle between the booms in the deep digging posture. Let γ be α>γ> β (1) Here, γ is an angle at which the upper boom is almost perpendicular to the ground surface.

Therefore, when the lower boom 14 is raised to take a turning posture, the opening angle between the booms is increased by the cross link 15, and the lower boom 14 and the upper boom 17 are greatly opened above the upper revolving unit 11 so that the front boom is within the vehicle width. The structure 1 can be stored. FIG. 4 shows a state viewed from directly above at this time. Further, when the lower boom 14 is lowered from the turning posture, the opening angle between the booms is reduced by the cross link 15, and the maximum reach length from the turning center portion to the tip of the bucket 22 is shortened at the maximum reach position, and the tipper falls at this time. The moment can be reduced and stability can be improved. In the deep digging posture in which the lower boom 14 is further lowered, the opening angle between the booms is increased again, so that the bucket 22 can be moved to a deep position and deep digging can be performed.

In the present embodiment, the swing angle β of the lower boom 14 at the maximum reach position of the front structure 1 does not coincide with the predetermined angle φ that minimizes the opening angle between the booms. It can also be set to match, thereby minimizing the maximum reach length and maximizing the effect of improving stability.

In the swing post 13 of the excavator according to the present embodiment, the connection point between the lower boom 14 and the swing post 13 is located behind the swing center of the swing post 13 with respect to the front structure 1 as described above. positioned. FIG. 5A is an enlarged view showing the situation. On the other hand, the horizontal pin 31a, which is the connection point between the lower boom 14a and the swing post 13a, is connected to the swing post 13a.
FIG. 5B illustrates a comparative example in which the swing pin 30a, which is the swing center of FIG.
Is shown in an enlarged view. However, the position of the swing pin 30a on the upper swing body is the same as the position of the swing pin 30.
In both FIGS. 5A and 5B, horizontal pins 16A and 16C for connecting the bottom ends of the boom cylinders 16 and 16a to the swing posts 13 and 13a, respectively.
, Respectively, are located forward of the swing pins 30, 30a. In a conventional swing type excavator, FIG.
As in (b), the connection point between the boom and the swing post is
The swing post was located closer to the front structure than the swing center.

FIG. 6 is a diagram comparing the movement of the front structure attached to the swing post of FIGS. 5 (a) and 5 (b). However, the movement of the front structure of the present embodiment shown in FIG. 5A is shown by a solid line, and the movement of the front structure of the comparative example of FIG. 5B is shown by a two-dot chain line. As in this example,
By positioning the swing center of the lower boom 14 in the vertical direction behind the swing center of the swing post 13 with respect to the front structure 1, the swing center of the upper swing body 11 moves vertically above and below the front structure 1 including the lower boom 14. The swing center of the direction can be made closer. Therefore, the minimum turning radius can be further reduced by the length indicated by the shortened amount a in FIG. 6, and the opening between the booms required to accommodate the front structure 1 within the vehicle width is equivalent to the shortened amount a. The load on the cross link can be reduced by reducing the amount of increase in the angle. Further, by bringing the swing center of the front structure 1 closer to the center of rotation of the upper swing body 11, the maximum reach length from the center of rotation to the tip of the bucket 22 is shortened by the length indicated by the shortened amount b in the figure. The overturning moment at this time can be reduced to improve the stability.

FIG. 7 is a view showing a situation at the time of excavating a gutter.
FIG. 7A shows the case of the present embodiment shown in FIG.
FIG. 5B shows the case of FIG. In each case, the upper revolving structure 11 is turned 90 ° to the right in the figure and the front structure is swung 90 ° to the left in the figure, and the state where the gutter is excavated at the farthest limit position in the vehicle width direction is shown. However, FIG.
In FIG. 7B, members equivalent to those in FIG. In this embodiment shown in FIG. 7A, the vertical swing center of the lower boom 14 (the position of the horizontal pin 31).
7B is lower than the plane of FIG. 7B, but the swing center (swing pin position) of the swing post 13 is the same as described above. 7A and 7B, the gutter distance δ is the same in FIGS. 7A and 7B. If the swing center position of the swing post 13 is not changed, the gutter can be excavated at the same distance as the conventional one. There is no sacrifice in distance.

Also, as shown in FIG. 6, the vertical swing center of the lower boom 14 is brought closer to the center of rotation of the upper swing body 11, and the lower boom 14 can move backward with respect to the front structure 1. When loading earth and sand from the bucket 22 to the dump, etc.
Loading of earth and sand becomes easy.

The positional relationship between the horizontal pin 16A at the end of the boom cylinder 16 foot and the swing pin 30 is not limited to that shown in FIG.

In this embodiment as described above, the boom is constituted by the lower boom 14 and the upper boom 17,
The opening angle between the two booms is changed by the cross link 15 according to the swing angle of the lower boom 14, and the opening angle between the booms is increased when the turning posture with the lower boom 14 raised is increased. 1 can be paid. Further, since the upper revolving unit 11 can be turned within substantially the vehicle width of the lower traveling unit 10, turning within the vehicle width becomes possible.
Therefore, the vehicle can be turned within the vehicle width by using a swing system having a simple structure without using a complicated parallel link mechanism. Also, when the lower boom 14 is raised, the opening angle between the booms increases, so that the front structure is swung toward the cab side.
When the arm 19 is rolled up while swinging the lower boom 14 upward in the running state, the bucket 22 passes over the cab 12 and the bucket 22 can be prevented from hitting the cab 12 (described later).

Further, since the swing post 13 is installed at a position in front of and at the side of the cab 12, the boom can be raised to the maximum without displacing the cab 12 rearward and without causing the lower boom 14 to interfere with the cab 12. The swing angle at the time can be increased. Therefore, when turning within the vehicle width is enabled, the degree of freedom in designing the layout of the cab 12 in the narrow upper-part turning body 11 can be increased. For example, the driver's cab 12 can be moved forward, so that the size of the engine can be increased accordingly, and the design of the upper-part turning body can be relaxed.

When the swing post is installed in front of and in the side of the driver 's cab , the boom is raised and the arm is entangled with the swing post and the front structure generally swinging at a right angle position on the driver's cab side. Occasionally, there is concern that the bucket will hit the cab. However, in this embodiment, a remarkable effect on this is obtained. That is, when the lower boom 14 is raised, the cross link 15 that increases the opening angle between the upper boom 17 and the lower boom 14 in response to the swing post 13 and the front structure 1 is provided at a right angle position on the driver's cab 12 side. The lower arm boom 14 is raised with the arm 1
When the bucket 9 is involved, the bucket 22 passes over the cab 12, and there is no fear that the bucket 22 hits the cab 12.

Further, one end of the cross link 15 is connected to the swing post 13 via a horizontal pin 35, and the distal end is connected to the upper boom 17 via a horizontal pin 32. Since it intersects with the straight line connecting the pin 31, the opening angle between the booms can be increased at the maximum raising position of the lower boom 14, and a turning posture narrower than the vehicle width can be taken at this position.

Further, since the horizontal pin 35 at one end of the cross link 15 is disposed rearward of the front structure 1 with respect to the horizontal pin 31 at the end on the foot side of the lower boom 14, the boom is at the maximum reach position where the lower boom 14 is lowered. The opening angle can be reduced, and the falling moment at this time can be reduced to improve the stability. Further, in a deep digging posture in which the lower boom 14 is further lowered, the opening angle between the booms can be increased, and deep digging can be performed.

The lower boom 14 and the swing post 1
3 is located rearward of the front structure 1 with respect to the swing center of the swing post 13 so that the minimum turning radius can be further reduced, and the front structure 1 is accordingly positioned within the vehicle width. The load on the cross link 15 can be reduced by reducing the amount of increase in the opening angle between the booms required to accommodate it. Further, the maximum reach length can be shortened, and the overturning moment at this time can be reduced to improve the stability. Further, since the swing center of the swing post 13 is not changed, the distance of the side groove is not sacrificed. Further, in this case, when the excavated earth and sand is loaded from the bucket 22 to a dump or the like, a large foot portion can be taken, so that loading becomes easy.

In the present embodiment, which is a swing system, the offset system is not employed, so that the front structure 1 can be reduced in weight and the stability can be improved. In addition, since the counterweight can be reduced, the weight of the body itself can be reduced, and the transportation cost can be reduced. Further, by reducing the weight of the body, the output of the prime mover can be reduced, the manufacturing cost and the running cost can be reduced, and the fuel efficiency can be improved.

Since the offset method is not used,
The number of locations where the vertical pins are used is reduced, and the range of applications is expanded without being restricted by the conventional front attachment. In addition, since the lower part of the parallel link mechanism does not interfere with the ground surface when excavating the gutter, the excavation depth can be made larger than that of the standard machine. Further, since there is no complicated parallel link mechanism, the manufacturing cost is reduced and the maintainability is improved.

In the offset method, when the arm and the bucket are offset to the side opposite to the cab, the boom may obstruct the view and make it difficult to see the excavation position from the cab. Because of the swing method for connecting the structures 1, the field of view from the cab 12 is widened, and the bucket is clearly visible. Therefore, the driver can operate the vehicle stably mentally, and is safer than the offset method.

Further, since the offset system is not used, the cab 12 and the front structure 1 do not greatly interfere with each other. However, when the front structure 1 swings to the opposite side to the cab 12, the cab 12 and the front structure 1 may slightly interfere with each other only when the lower boom 14 swings upward. Since only the lower boom 14 is used, the interference prevention area can be easily calculated simply by detecting only the vertical swing angle and the swing angle of the lower boom 14. Therefore, unlike the conventional offset method, it is not necessary to detect all angles of the front structure of the ultra-small turning hydraulic excavator, and an inexpensive and highly reliable interference prevention device can be realized.

Next, another embodiment of the swing type excavator according to the present invention will be described with reference to FIG.
However, in FIG. 8, the same reference numerals are given to members equivalent to those in FIGS.

As shown in FIG. 8, the swing post 13A
, The horizontal pin 35A at one end of the cross link 15A
Is located forward of the horizontal pin 31A at the end on the foot side of the lower boom 14A.
A crosses a straight line connecting the horizontal pin 32A connecting the upper boom 17 and the lower boom 14A and the horizontal pin 31A connecting the lower boom 14A and the swing post 13A.

Horizontal pin 32A at the tip of lower boom 14A
Is a circle centered on the horizontal pin 31A (indicated by a dashed line in the figure), and the trajectory of the horizontal pin 34A at the tip of the cross link 15A is a circle centered on the horizontal pin 35A (indicated by the dashed line in the figure). However, in this embodiment, the locus of the horizontal pin 32A at the distal end of the lower boom 14A and the horizontal pin 34A at the distal end of the cross link 15A are set to overlap as shown in FIG. Then, similarly to FIG. 3, the locus of the horizontal pin 34A at the tip of the cross link 15A is
When it is outside the locus of the horizontal pin 32A at the tip of A,
The opening angle between the booms increases, and vice versa, the opening angle between the booms decreases.

Therefore, for example, when raising the lower boom 14 to take a turning posture, the cross link 15
When the lower boom 14 is lowered from the turning posture, the opening angle between the booms is reduced by the cross link 15. In the case of this embodiment, the relationship among the opening angle α in the turning posture, the opening angle β in the maximum reach position, and the opening angle γ in the deep digging posture is as follows: α>β> γ (2)

Also in this case, when the lower boom 14 is lowered from the turning posture, the opening angle between the booms decreases, and at the maximum reach position, the maximum reach length from the center of rotation to the tip of the bucket 22 becomes shorter. The stability can be improved by reducing the moment. If the opening angle between the booms in the turning posture can be increased,
By adjusting the position of the horizontal pin 35 of the cross link 15 and the length of the cross link 15, the magnitude relationship between α, β, and γ can be arbitrarily set, and for example, the maximum reach length can be increased. .

According to this embodiment as described above, the connecting position (horizontal pin 35A) at one end of the cross link 15A comes before the connecting position (horizontal pin 31A) of the lower boom 14A on the swing post 13A. The front and rear lengths of the swing post 13A can be shortened, and the size of the swing post 13A itself can be reduced, thereby increasing the degree of freedom in design.

Also in this case, the maximum reach length can be reduced at the maximum reach position, and the overturning moment at this time can be reduced to improve the stability.

Next, still another embodiment of the swing type excavator according to the present invention will be described with reference to FIGS. However, in FIG. 9, the same members as those in FIG. 1 are denoted by the same reference numerals.

As shown in FIG. 9, in this embodiment, an upper boom cylinder 40 is used as an opening angle adjusting means instead of the crosslinks shown in FIGS. That is, the upper boom cylinder 40 is connected between the swing post 13 and the upper boom 17, and a force for changing the opening angle between the upper boom 17 and the lower boom 14 (opening angle between the booms) is generated by expansion and contraction. Other configurations are the same as those in FIG. 1 and FIG.

FIG. 10 is a schematic view of a main part of a hydraulic circuit which is a means for controlling expansion and contraction of the upper boom cylinder 40 of the present embodiment. In FIG. 10, a sensor 41 detects the elevation angle (vertical swing angle) θ of the lower boom, and a sensor 42 detects an opening angle ε between the booms. The controller 43 inputs the angles θ and ε from the sensors 41 and 42, respectively, and inputs a voltage signal 43a based on the flow rate to the upper boom cylinder 40 to the amplifier 44. The amplifier 44 converts the voltage signal 43a into a current signal 44a, and the operating position of the direction switching valve 45 is determined by the current signal 44a. The oil pumped by the hydraulic pump 47 from the tank 46 based on the operation position of the direction switching valve 45 is supplied to the rod-side port 40a and the bottom-side port 40b of the upper boom cylinder 40 at a constant rate, and the upper boom cylinder 40 expands and contracts. I do. A certain back pressure is applied to the circuit by the back pressure valve 48.

As shown in FIG. 11, the controller 43 has an operation unit 43A, a first memory 43B, and a second memory 43C. The first memory 43B stores the value of the inter-boom angle θ ₀ at the start of the work, and the second memory 43C is a function memory storing a function table between the angles θ and ε. In the controller 43,
The detected angles θ and ε are input to the calculation unit 43A, and calculate the voltage signal 43a based on the flow rate to the upper boom cylinder 40 while exchanging data with the first memory 43B and the second memory 43C.

The control flow of the upper boom cylinder 40 performed by the controller 43 will be described with reference to FIG. However, this calculation and control procedure is performed by dividing the operation time into a certain sampling time Δt (seconds). First, step S1
Then, the initial value of the elevation angle of the lower boom 14 before operating the lower boom 14 is input and stored in the first memory 43B as θ _{0 in} advance. Then, in step S2, it is determined whether or not time has elapsed by Δt after the start of the operation.
After elapse, the process moves to the next step S3.

In step S3, the elevation angle θ of the lower boom 14 and the opening angle ε between the booms are detected by the sensors 41 and 42, respectively, and are read into the calculation unit 43A. Next, in step S4, the previous elevation angle θ ₀ of the lower boom 14 (before the time Δt) is read from the first memory 43B. Next, in step S5, the elevation angle (hereinafter, referred to as [θ]) after Δt from the present time is calculated. At this time, [θ] = 2θ−θ ₀ (3). This is because the elevation angle velocity of the lower boom 14 is θ
^{If *} , then θ ^* = (θ−θ ₀ ) / Δt (4), so that [θ] = θ + θ ^* · Δt = 2θ−θ ₀ (5)

Next, in step S6, [ε] corresponding to the above [θ], that is, the opening angle between booms after Δt from the present time is read from the function table of the second memory 43C. Also,
In step S7, θ ₀ in the first memory 43B is rewritten to θ, and this is set as new θ ₀ . Next, step S8
, The opening angular velocity between the booms after Δt from the present
[ε ^* ] is calculated according to the following equation: [ε ^* ] = ([ε] −ε) / Δt (6)

In the next step S 9, the expansion / contraction speed of the upper boom cylinder 40 is calculated using this [ε ^* ] and a geometrical relational expression. However, this geometrical relation is expressed by the upper boom cylinder 40 and the lower boom 14
, And the connection position of the upper boom cylinder 40 and the lower boom 14 on the swing post 13 and the like, and are stored in the calculation unit 43A. Then, in the next step S10, the flow rate of the oil to be supplied to the upper boom cylinder 40 is calculated from the expansion / contraction speed of the upper boom cylinder 40, and the flow proceeds to step S11.
Outputs the result (voltage signal 43a) to the amplifier 44. Next, it is determined in step S12 whether or not the operation is to be ended. If the operation is to be ended, the procedure is ended. If not, the procedure returns to step S1 to repeat the same procedure.

According to the present embodiment as described above, the opening angle between the booms can also be reduced by means of the upper boom cylinder 40 and the controller 43 for controlling the expansion and contraction of the lower boom.
4 can be changed according to the vertical swing angle. Further, in this case, the expansion and contraction of the upper boom cylinder 40 can be changed at an arbitrary ratio, and the opening angle between the booms can be changed at an arbitrary ratio.

As a modification of the above embodiment, FIG.
As shown in FIG. 3, the upper boom cylinder 50 is connected to the lower boom 1
The same effect can be obtained by connecting between the upper boom 17 and 4. However, in FIG. 13, members equivalent to those in FIG. 9 are denoted by the same reference numerals.

In the above embodiment, the swing post 13 is installed at a position on the upper side of the revolving superstructure 11 in front of the driver's cab 12, but the present invention is not limited to this. For example, if the layout of the driver's cab can be changed, a swing post may be installed at the center of the upper revolving structure in front of the driver's cab, or the front right corner of the driver's cab is cut out to create a space, A swing post may be installed at that position. Even in such a case, the present invention can be applied to obtain the same effect.

[0091]

According to the present invention, since the boom is composed of the lower boom and the upper boom and the opening angle adjusting means is provided between the lower and upper booms, the upper swing body and the entire front structure can be turned within the vehicle width by a simple swing method. Becomes possible. Also, Freon
When the arm is involved while swinging the lower boom upward while the structure is swung to the cab side , the bucket can be prevented from hitting the cab.

Since the offset method is not adopted,
The weight of the front structure can be reduced, and the stability can be improved. Further, the weight of the body can be reduced, the transportation cost, the manufacturing cost, the running cost can be reduced, and the fuel efficiency can be improved. In addition, without being restricted by the conventional front attachment, the range of applications is expanded, and there is no interference with the ground surface when excavating gutters.
Maintenance is also improved. Furthermore, because of the swing system, the field of view from the driver's cab is widened, the bucket is clearly visible, and the driver can operate mentally stably, which is safer than the offset system.

Also, the driver's cab and the front structure may interfere with each other only when the lower boom is swung upward in a state where the front structure swings to the opposite side of the driver's cab. Since only the lower boom is used, the interference prevention area can be easily calculated, and an inexpensive and highly reliable interference prevention device can be realized.

Also, since the swing post is installed at the front and side of the cab of the upper revolving unit, the cab is not displaced backward, and the lower boom is not interfered with the cab and the boom can be moved up to the maximum when the boom is raised. The swing angle can be increased,
It is possible to increase the degree of freedom in designing the cab layout in the narrow upper-part turning body. In addition, since the position of the swing post is set to the side in combination with the opening angle adjusting means for increasing the opening angle between the booms according to the rise of the lower boom, the state in which the front structure is swung at a right angle position on the driver's cab side. Thus, when the lower boom is raised and the arm is involved, there is a remarkable effect that there is no concern that the bucket hits the cab.

Also, since the opening angle between the booms is reduced when the lower boom is swung downward, the maximum reach can be reduced to reduce the overturning moment and the stability can be improved. Furthermore, when swinging the lower boom downward, the opening angle between the booms is increased,
The bucket can be moved to a deep position, and deep digging can be performed.

Further, since the connecting point between the lower boom and the swing post is located behind the swing structure of the swing post with respect to the front structure, the minimum turning radius can be further reduced without sacrificing the side groove distance. Accordingly, the increase in the opening angle between the booms required to fit the front structure within the vehicle width can be reduced, and the load on the opening angle adjusting means can be reduced. In addition, the maximum reach length can be shortened, and the overturning moment at this time can be reduced to improve the stability. further,
When loading excavated earth and sand into a dump or the like, the foot part can be made large, making loading easier.

Further, since the position of the connecting point between the cross link and the swing post is on the front structure side from the position of the connecting point between the lower boom and the swing post, the size of the swing post itself can be reduced. Design flexibility is increased. Also, the maximum reach length can be shortened,
The stability can be improved by reducing the overturning moment.

Further, since the opening angle adjusting means is constituted by the hydraulic cylinder and the means for controlling the expansion and contraction of the hydraulic cylinder, the opening angle between the booms can be changed according to the swing angle of the lower boom. The opening angle can be changed at an arbitrary rate.

[Brief description of the drawings]

FIG. 1 is a side view showing a configuration of a swing type excavator according to an embodiment of the present invention.

FIG. 2 is a top view of the excavator of FIG.

FIG. 3 is a view for explaining an operation of a front structure in the excavator of FIGS. 1 and 2;

FIG. 4 is a top view in the case of the turning posture of FIG. 3;

5 (a) is an enlarged view of a swing post in the excavator of FIGS. 1 and 2, and FIG. 5 (b) is a view showing a comparative example in which a horizontal pin is located closer to a front structure than a swing pin. .

FIG. 6 is a diagram showing a comparison of the movement of a front structure attached to the swing post of FIGS. 5 (a) and 5 (b).

FIG. 7 is a top view showing a situation at the time of gutter excavation;
FIG. 5A shows the case of the present embodiment shown in FIG.
It is a figure in the case of (b).

FIG. 8 is a side view showing the configuration and operation of a swing type excavator according to another embodiment of the present invention.

FIG. 9 is a side view showing the configuration and operation of a swing type excavator according to still another embodiment of the present invention.

FIG. 10 is a schematic view of a main part of a hydraulic circuit of the upper boom cylinder of FIG. 9;

FIG. 11 is a diagram illustrating a configuration of a controller in FIG. 10;

FIG. 12 is a diagram illustrating a control flow of an upper boom cylinder performed by the controller of FIG. 11;

FIG. 13 is a view showing a modification of FIG. 9 in which an upper boom cylinder is connected between a lower boom and an upper boom.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front structure 10 Lower traveling body 11 Upper revolving structure 12 Operator's cab 13 Swing post 13A Swing post 14 Lower boom 14A Lower boom 15 Cross link 15A Cross link 16 Boom cylinder 17 Upper boom 19 Arm 22 Bucket 23 Swing cylinder 30 Swing pin 31, 32 Horizontal Pins 31A, 32A Horizontal pins 34, 35 Horizontal pins 34A, 35A Horizontal pins 40 Upper boom cylinder 43 Controller 45 Directional switching valve 46 Tank 47 Hydraulic pump 50 Upper boom cylinder

Continuation of the front page (56) References JP-A-63-272820 (JP, A) JP-A-52-146001 (JP, A) JP-A-2-84857 (JP, U) JP-A-58-140253 (JP) , U) Fully open sho 61-71643 (JP, U) Fully open sho 59-1760 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02F 3/32 E02F 3/38 E02F 9/14 E02F 9/24 E02F 3/36

Claims (12)

(57) [Claims] An undercarriage, an upper revolving structure pivotally mounted on the lower revolving structure, and a front structure including a cab, a bucket, an arm, and a boom mounted on the upper revolving structure. A swing type excavator, wherein a swing post is installed on the upper swing body, and a boom of the front structure is connected to the swing post so that the entire front structure can swing horizontally. A lower boom capable of swinging the body in a size substantially rotatable within the vehicle width of the lower traveling body, and swinging a boom of the front structure up and down with respect to the swing post; An upper boom capable of swinging upward and downward, and the lower boom and the upper boom are attached to the front structure in accordance with a vertical swing angle of the lower boom. An opening angle adjusting means for changing an opening angle in a vertical direction with the paboom is provided, and the swing post is installed at a position forward and sideward of the cab of the upper swing body, and the opening angle adjusting means comprises: Front structure is maximum lee
The lower boom is higher than in the position
When the front structure is turned to the turning posture
Is the vertical direction between the lower boom and the upper boom.
Opening angle becomes larger, and when the pre-SL front structure the turning posture, the vertical direction of the lower boom so that the entire the front structure fits within the turning circle of the upper rotating body
A swing type excavator, wherein an opening angle between the lower boom and the upper boom is changed according to a swing angle of the excavator. 2. An undercarriage, an upper revolving structure pivotally mounted on the lower traveling structure, and a front structure including a cab, a bucket, an arm, and a boom mounted on the upper revolving structure. A swing type excavator, wherein a swing post is installed on the upper swing body, and a boom of the front structure is connected to the swing post so that the entire front structure can swing horizontally. A lower boom capable of swinging the body in a size substantially rotatable within the vehicle width of the lower traveling body, and swinging a boom of the front structure up and down with respect to the swing post; An upper boom capable of swinging upward and downward, and the lower boom and the upper boom are attached to the front structure in accordance with a vertical swing angle of the lower boom. An opening angle adjusting means for changing an opening angle in a vertical direction with the paboom is provided, and the swing post is installed at a position forward and sideward of the cab of the upper swing body, and the opening angle adjusting means comprises: Front structure is maximum lee
The lower boom is higher than in the position
When the front structure is turned to the turning posture
Is the vertical direction between the lower boom and the upper boom.
When the opening angle is increased, and the arm is involved while swinging the lower boom upward in a state where the front structure is swung toward the cab side, the bucket passes over the cab. Of the lower boom
A swing type excavator, wherein an opening angle between the lower boom and the upper boom is changed according to a vertical swing angle . 3. The swing type excavator according to claim 1, wherein said opening angle adjusting means is provided on said lower boom.
The swing angle is at least the maximum reach position of the front structure
When the swing angle is larger than the swing angle in the position, the swing angle of the lower boom is changed so that the swing angle of the lower boom and the upper boom is increased by swinging the lower boom upward. Swing type excavator. 4. The swing type excavator according to claim 1, wherein said opening angle adjusting means raises said lower boom upward in a first region in which a swing angle of said lower boom is larger than a predetermined swing angle. As the rocking motion increases, the opening angle between the lower boom and the upper boom increases, and when the rocking angle of the lower boom is smaller than the predetermined rocking angle, the lower boom is rocked downward. A swing type excavator, wherein an opening angle between the lower boom and the upper boom is increased, and the opening angle is changed such that the opening angle is minimized at the predetermined swing angle. 5. The swing type excavator according to claim 4, wherein said opening angle adjusting means is configured such that a swing angle of said lower boom at a maximum reach position of said front structure substantially coincides with said predetermined swing angle. A swing type excavator characterized by being set to perform. 6. The swing type excavator according to claim 1 or 2, wherein the opening angle adjusting means is arranged such that when the swing angle of the lower boom is near the maximum raising angle of the lower boom, it is larger than when the swing angle of the lower boom is near the maximum lowering angle. A swing type excavator, wherein the opening angle between the lower boom and the upper boom is changed so as to increase the opening angle. 7. The swing type excavator according to claim 1, wherein a connection point between the lower boom and the swing post is located rearward of a front structure with respect to a swing center of the swing post. A swing type excavator characterized by the above-mentioned. 8. The swing type excavator according to claim 1, wherein said opening angle adjusting means includes a connecting point between said lower boom and said swing post and said lower boom in at least a part of a swing range of said lower boom. One end is connected to the swing post via a horizontal pin, and the other end is a cross link connected to the upper boom via a horizontal pin so as to intersect a straight line connecting the connection points of the upper boom and the upper boom. A swing type excavator, characterized in that: 9. The swing type excavator according to claim 8, wherein a position of a connecting point between the cross link and the swing post is located on a front structure more than a position of a connecting point between the lower boom and the swing post. A swing type excavator, which is located behind the excavator. 10. The swing type excavator according to claim 8, wherein a position of a connection point between the cross link and the swing post is closer to a front structure than a position of a connection point between the lower boom and the swing post. A swing type excavator, characterized by being located in a country. 11. The swing type excavator according to claim 1, wherein the opening angle adjusting means has one end connected to the swing post via a horizontal pin, and the other end connected to the upper boom via a horizontal pin. And a means for controlling expansion and contraction of the hydraulic cylinder such that an opening angle between the lower boom and the upper boom changes according to a vertical swing angle of the lower boom. Swing type excavator. 12. The swing type excavator according to claim 1, wherein the opening angle adjusting means has one end connected to the lower boom via a horizontal pin and the other end connected to the upper boom. And a means for controlling expansion and contraction of the hydraulic cylinder so that an opening angle between the lower boom and the upper boom changes according to a vertical swing angle of the lower boom. Swing type excavator.