JP2002088792A - Offset boom type construction machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a working device while ensuring the performance of the working device in a practical range by setting the offset range of a bucket smaller so that the offset range can correspond to an interval between crawlers. SOLUTION: The working device 31 is composed of a lower boom 32, an upper boom 35, an arm stay 38, an arm 41, the bucket 44 and the like. The maximum movement position on the left side of the bucket 44 is taken as a position such that a left side cutter 44E is approximately linearly aligned with the inner side surface 2A of the crawler 2, and the maximum movement position on the right side of thereof is set as a position such that a right side cutter 44F is approximately linearly aligned with the inner side surface 3A of the crawler 3. Consequently, the offset quantity D of the bucket 44 can be set smaller so as to correspond to the range of practical use, and the upper boom 35, the offset cylinder 37, etc., can be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an offset boom type construction machine suitably used for excavating work such as grooving by offsetting a working device, for example, left and right with respect to a vehicle body.

[0002]

2. Description of the Related Art Generally, as an offset boom type construction machine, a work implement such as a bucket is moved left and right by using, for example, an offset cylinder to excavate a trench or the like on the left or right side in front of a vehicle body. 2. Description of the Related Art A hydraulic excavator configured to perform an operation is known (for example, Japanese Patent Application Laid-Open No.
No. 36112, JP-A-2000-73390, etc.).

A conventional hydraulic shovel of this type will be described with reference to FIGS.

In the drawing, reference numeral 1 denotes a lower traveling body of a hydraulic shovel,
The undercarriage 1 is a center frame 1A (see FIG. 10).
Provided on both the left and right sides of the center frame 1A,
It is generally constituted by side frames 1B, 1B extending in the front and rear directions.

[0005] Reference numerals 2 and 3 denote left and right crawler belts respectively wound around the side frames 1B. The crawler belts 2 and 3 are driven by a traveling motor (not shown) provided on the lower traveling body 1. , A hydraulic excavator is run. Also,
The inner surface 2A of the crawler belt 2 located on the left side and the inner surface 3A of the crawler belt 3 located on the right side are opposed to each other with an interval W in the left and right directions as shown in FIG.

[0006] Reference numeral 4 denotes an upper revolving unit which is rotatably mounted on the center frame 1A of the lower traveling unit 1.
Is provided on a turning frame 5 formed as a support structure having a bottom plate 5A and left and right vertical plates 5B, 5B, and a driver's seat (not shown) is provided on the front left side of the turning frame 5. Provided on the rear side of the cab 6, and the like,
A counter for providing weight balance between a building cover 7 covering various devices such as an engine (not shown) mounted on the revolving frame 5 and a working device 9 provided on the rear end side of the revolving frame 5 to be described later. And a weight 8.

In this hydraulic excavator, as shown in FIG. 9, the upper revolving unit 4 is formed in a substantially circular arc shape that fits within the width dimension (vehicle width) of the lower traveling unit 1, and an ultra-small turning type excavator. Is configured as In addition, the cab 6
It is formed in a substantially box shape having left and right side portions and an upper surface portion, and its right side portion 6A is arranged facing a lower boom 10 described later.

A working device 9 is provided on the front side of the upper revolving unit 4 so as to be able to move up and down. The working device 9 is constituted by a lower boom 10, an upper boom 13, an arm stay 16, an arm 19, a bucket 22, and the like, which will be described later. It is configured.

Reference numeral 10 denotes a lower boom whose base end is attached to each vertical plate 5B of the turning frame 5 via a lower boom connecting pin 11. The lower boom 10 is raised and lowered by a boom cylinder 12. .

Reference numeral 13 denotes an upper boom which is attached to the distal end of the lower boom 10 via an upper boom connecting pin 14. The upper boom 13 is provided between the left side surface and the lower boom 10 as shown in FIGS. When the offset cylinder 15 expands and contracts, it swings left and right about the axis Oa-Oa of the connecting pin 14.

The upper boom 13 is connected to the axis Oa.
-Oa and the axis Ob of the arm stay connecting pin 17 described later-
The lower boom 10 has a length La which is substantially equal to or slightly shorter than the length of the lower boom 10. Also, upper boom 13
Is larger than a length Lb of an arm stay 16 described later (La> Lb), and the sum of these lengths La and Lb is constant in excavation work such as grooving. In order to secure the excavation depth, the total dimension Lt is predetermined (Lt = La + Lb).

Reference numeral 16 denotes an arm stay which is attached to the distal end of the upper boom 13 via an arm stay connecting pin 17. The arm stay 16 is connected to an axis Ob- of the connecting pin 17.
It can swing left and right around Ob.
The arm stay 16 is located between the axis Ob-Ob and the center of an arm connecting pin 20 described later, and has a dimension Lb along the length direction of the upper boom 13.

The arm stay 16 is connected to the lower boom 10 through a rod-like link 18. Thus, when the upper boom 13 swings left and right, as shown in FIG.
The bucket 22 and the like move (offset) to the left or right while maintaining a state substantially parallel to the lower boom 10 by the link 18.

In this case, the conventional hydraulic excavator is configured such that when the upper boom 13 swings left and right and the bucket 22 is offset to the left or right maximum movement position shown in FIG. The parts and the like protrude from the crawler tracks 2 and 3 by a certain size in the left and right directions, and the bucket 2 between these left and right maximum movement positions is configured.
The movement amount (offset amount) d of No. 2 is set to be larger than the vehicle width.

Reference numeral 19 denotes an arm attached to the tip end of the arm stay 16 via an arm connecting pin 20. The arm 19 is moved up and down by an arm cylinder 21.

Reference numeral 22 denotes a bucket attached to the tip end of the arm 19, and the bucket 22 is rotated by a bucket cylinder 23.

During excavation work with a hydraulic excavator, first, the offset cylinder 15 is expanded and contracted to swing the upper boom 13 left and right to move the arm stay 16, the arm 19, the bucket 22 and the like to the left or front of the vehicle body. By offsetting to the right and rotating the lower boom 10, the arm 19, and the bucket 22 upward and downward at this offset position, for example, grooving is performed as shown in FIG.

In this trenching operation, for example, the steel plate 2
While excavating work, the excavator moves forward and backward while straddling the groove while retaining the soil on the side wall of the groove using 4 or the like. In this case, if the ground is excavated before and after the crawler tracks 2 and 3, the foot of the hydraulic excavator becomes unstable. Therefore, the excavation range of the groove in the left and right directions of the vehicle is the distance W between the crawler tracks 2 and 3.
In many cases.

[0019]

By the way, in the above-mentioned prior art, the working device 9 has an offset d larger than the vehicle width. However, in ordinary civil engineering work using a hydraulic excavator, the bucket 22 is often used by moving the bucket 22 leftward and rightward within the range of the vehicle width. Since it is often used for small-scale work sites such as water supply works in urban areas, it is common practice to dig trenches only within a range corresponding to the interval W between the crawler tracks 2 and 3.

For this reason, in the prior art, the offset d of the working device 9 is set wider than the actual use range, and the length La of the upper boom 13 is required to give the offset d. Since the size becomes larger as described above, for example, a large offset cylinder 15 or the like having a large stroke and an expansion and contraction force is required, and there is a problem that the weight increases and the cost increases.

Further, for example, when digging a groove on the left side, as shown in FIG. 10, the long upper boom 13 enters the groove obliquely, so that the middle part thereof is
Thus, there is a problem that the excavation work cannot be performed smoothly.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to make it possible to appropriately set the offset amount of a working device in accordance with an actual use range, and to reduce the size of an upper boom and an offset cylinder. Another object of the present invention is to provide an offset boom type construction machine capable of performing civil works such as digging and the like in a smooth manner.

[0023]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a first aspect of the present invention is a lower traveling body provided with crawler tracks on both the left and right sides, and is mounted on the lower traveling body so as to be pivotable. A revolving superstructure, and a working device mounted on the front side of the upper revolving structure, wherein the working device has a base end mounted on the upper revolving structure so as to be able to move up and down, and a boom cylinder. A lower boom, a lower boom mounted on the distal end of the lower boom so as to swing left and right, and an upper boom operated by an offset cylinder, and a lower boom mounted on the distal end of the upper boom so as to swing left and right. An arm stay which is held substantially parallel to the lower boom by a link, an arm which is mounted on the distal end side of the arm stay so as to be able to move up and down, and which is operated by an arm cylinder; In an offset boom type construction machine comprising a bucket mounted on a tip end of an arm and operated by a bucket cylinder, the working device is configured such that when the upper boom swings leftward by the offset cylinder and the bucket moves leftward, The position where the left side surface of the bucket is substantially linearly aligned with the inner side surface of the crawler belt is defined as the leftmost maximum movement position. When the upper boom swings rightward and the bucket moves rightward, the right side of the bucket moves. A position where the surface is substantially linearly arranged with respect to the inner side surface of the crawler belt is defined as a rightmost maximum movement position.

With this configuration, for example, when the upper boom is swung to the leftmost position, the bucket can be moved to the leftmost position within a range corresponding to the interval between the crawler belts, and this position is moved to the leftmost position. Location. Also, when the upper boom is swung to the far right, the bucket can be moved to the rightmost maximum movement position, which is the position closest to the right between the crawler tracks. Excavation work such as trenching can be performed.

Further, according to the invention of claim 2, a lower traveling body provided with crawler belts on both the left and right sides, and a driver's seat mounted on the lower traveling body so as to be pivotable, on one side in the left and right directions. An upper revolving structure provided with a cab or a canopy having the same, and a working device attached to a front side of the upper revolving structure, wherein the working device is configured such that a base end of the upper revolving structure is upwardly and downwardly raised. A lower boom movably mounted and operated by a boom cylinder, an upper boom slidably mounted on the distal end side of the lower boom in a left and right direction and operated by an offset cylinder, and a left and right direction on the distal end side of the upper boom An arm stay pivotally mounted on the arm stay and held substantially parallel to the lower boom by a link; and an arm cylinder mounted on the distal end side of the arm stay so as to be able to move up and down. Boom type construction machine, comprising an arm operated by the arm and a bucket mounted on the distal end side of the arm and operated by a bucket cylinder, the working device is configured such that the upper boom is moved to one side in the left and right directions by the offset cylinder. When the bucket moves to one side by swinging, a position where one side surface of the bucket is substantially linearly aligned with the inner side surface of the crawler belt is set as a maximum movement position on one side, and the upper boom is moved leftward and rightward. When the bucket swings to the other side and moves to the other side, a position where one side surface of the bucket is slightly away from the cab or canopy is set as a maximum movement position on the other side.

Thus, when the upper boom is swung to the leftmost side (cab side) with respect to the left and right directions,
The bucket can be moved to the maximum movement position on one side, which is the position closest to one side between the crawler tracks. Also, move the upper boom to the other side to the left and right (the side opposite to the cab).
Can be moved to a position slightly away from the cab or canopy in the left and right directions. Therefore, when the lower boom or the like is largely raised at this position, the bucket is moved with respect to the cab or the canopy. Can be lifted to these sides without interference.

According to the third aspect of the present invention, a lower traveling body provided with crawler tracks on both the left and right sides, an upper revolving body rotatably mounted on the lower traveling body, and A working device mounted on the front side, wherein the working device has a base end mounted on the upper revolving unit so as to be able to move up and down, and a lower boom operated by a boom cylinder, and a distal end of the lower boom An upper boom which is mounted to be swingable left and right on the side thereof and is operated by an offset cylinder; and an upper boom is mounted to be swingable left and right to the distal end side of the upper boom and is held substantially parallel to the lower boom by a link. An arm stay, an arm mounted on the distal end of the arm stay so as to be able to move up and down and operated by an arm cylinder, and a bucket mounted on the distal end of the arm In offset boom type construction machine comprising a bucket actuated by Toshirinda, the upper boom is thereby formed shorter than the lower boom, the upper boom is configured so as to form a shorter than arm stay.

Thus, the length of the upper boom can be made smaller than that of the lower boom, and the amount of movement (offset) of the bucket when the upper boom swings left and right can be set smaller. Also, for example, since the length of the arm stay can be increased by an amount corresponding to the shortened size of the upper boom, the total size of these can be maintained at a required size, and the upper boom, the arm stay, etc. can be extended to perform groove digging and the like. When performing excavation work, a sufficient excavation depth can be ensured.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An offset boom type construction machine according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking a micro turning hydraulic excavator as an example.

FIGS. 1 to 5 show a first embodiment of the present invention. In this embodiment, the same components as those of the prior art are denoted by the same reference numerals, and description thereof will be omitted. Shall be.

Reference numeral 31 denotes a working device of the hydraulic shovel according to the present embodiment. The working device 31 includes a lower boom 32, an upper boom 35, an arm stay 38, an arm 41, an arm 41, a bucket 44, and the like, which are substantially the same as in the prior art. Have been. However, in the present embodiment, the upper boom 35 is formed shorter than in the related art, and the offset amount D of the working device 31 is set to be smaller as described later.

Reference numeral 32 denotes a lower boom whose base end is attached to each vertical plate 5B of the revolving frame 5 via a lower boom connecting pin 33. The lower boom 32 is formed to have a predetermined length in substantially the same manner as in the prior art. , The boom cylinder 34 is moved upward and downward. On the left side of the distal end of the lower boom 32, a bracket 32 to which an offset cylinder 37 and a link 40 described later are attached is attached.
A, 32B and 32C are protruded.

An upper boom 35 is attached to the distal end of the lower boom 32 via an upper boom connecting pin 36. The upper boom 35 is connected to the connecting pin 36 by the expansion and contraction of an offset cylinder 37 as shown in FIGS. Is swung left and right about the axis OA-OA of FIG. Also, on the left side of the upper boom 35,
Bracket portions 35A, 35 for offset cylinder 37
A protrudes.

Here, the upper boom 35 is connected to the connecting pin 3
6 and the arm stay connecting pin 39 described later.
Has a length dimension LA located between the axis OB-OB of
This length LA is formed to be smaller than the length La of the related art, for example, to be 1/2 or less (LA ≦ La / 2).

The length LA of the upper boom 35
Is much shorter than the lower boom 32,
The arm stay 38 is formed to be smaller than a length dimension LB, which will be described later. That is, the dimensional relationship among the lower boom 32, the upper boom 35, and the arm stay 38 is set in advance as shown in the following equation (1).

[0036]

[Equation 1] Lower boom length> Upper boom length L
A <Arm stay length LB

As a result, as shown in FIG. 2, the working device 31 adjusts the movement amount (offset amount) D of the bucket 44 when the upper boom 35 swings between the leftmost position and the rightmost position. The offset amount D is set substantially corresponding to a few intervals W, and the offset amount D is set to be smaller than the offset amount d of the related art.

That is, for example, when the upper boom 35 is pivoted to the leftmost position, as shown in FIG. 3, the left side cutter 44E of the bucket 44 and the inner surface 2A of the left crawler belt 2 to be described later move forward, rearward or upward. , Are arranged substantially linearly in the downward direction, and the length dimension LA and the like of the upper boom 35 are set in advance so that the position of the bucket 44 at this time becomes the leftmost maximum movement position.

When the upper boom 35 is swung to the rightmost position, as shown in FIG. 4, the right side cutter 44F of the bucket 44 and the inner side surface 3A of the right crawler belt 3 are substantially linearly arranged. The position of the bucket 44 at this time is the rightmost maximum movement position.

In this case, in this embodiment, for example, a bucket 44 having a relatively small width dimension S is used.
When the bucket 44 is moved to the maximum movement position on the right side, the left side cutter 44E is
It is configured to be arranged on the right side of A.

Therefore, for example, when raising the working device 31 from the excavation position shown by the solid line in FIG. 5 to the turning position shown by the virtual line, first, the upper boom 35 is swung rightward to move the bucket 44 to the maximum position on the right side. The arm 44 and the bucket 44 are rotated so as to be folded toward the lower boom 32 while the lower boom 32 is moved upward from the excavation position while being held at the moving position. The cab 6 can be lifted upward from the right side along K.

37 is a lower boom 32 and an upper boom 35
With an offset cylinder provided to be able to expand and contract between
The offset cylinder 37 has the tube side attached to the bracket portions 32A and 32B of the lower boom 32, and the rod side attached to each bracket portion 35A of the upper boom 35. Further, as the offset cylinder 37, since the offset amount D of the bucket 44 is set to be small, a small cylinder having a reduced stroke, expansion and contraction force, and the like as compared with the related art is used.

Reference numeral 38 denotes an arm stay which is attached to the distal end of the upper boom 35 via an arm stay connecting pin 39 so as to swing left and right. The arm stay 38 is, as shown in FIGS. A stay body 38A whose base end is pin-connected to the upper boom 35, and side plate parts 38B, 38B fixed to the left and right sides of the distal end of the stay body 38A.
And bracket portions 38C, 38C for the link 40 project from the left side surface of the stay body 38A.

The arm stay 38 has a length LB located between the axis OB-OB of the arm stay connecting pin 39 and the center of an arm connecting pin 42 described later, and the length LB is The length of the upper boom 35 is made shorter than that of the related art by the shortened length. The total dimension LT obtained by adding these length dimensions LA and LB is formed substantially equal to the total dimension Lt of the conventional technique (LT 従 来 Lt).
In the excavation work such as trenching, the excavation depth is substantially the same as that of the conventional technology.

40 is a bracket 32 of the lower boom 32
B, 32C and each bracket 38A of the arm stay 38
The link 40 is a bar-shaped link provided between
The arm stay 38 and the like are held substantially parallel to the lower boom 10 in a manner similar to the prior art. Reference numeral 41 denotes an arm attached to the distal end side of the arm stay 38 via an arm connecting pin 42.
The arm cylinder 43 is raised and lowered in the upward and downward directions.

Reference numeral 44 denotes a bucket attached to the distal end of the arm 41. The bucket 44 has a concavely curved bottom plate 44A.
And left and right side plates 44 fixed to both sides of the bottom plate 44A.
B, 44C, a plurality of excavating claws 44D, 44D,... Protruding from the distal end of the bottom plate 44A, and are fixed to the outer surface of the left side plate 44B, and constitute the left side of the bucket 44 together with the side plate 44B. Side cutter 44E and right side plate 44
C, and fixed to the outer surface of the bucket 4 together with the side plate 44C.
4 and a right side cutter 44F constituting the right side surface.

As shown in FIG. 4, the bucket 44 is located between the left and right side cutters 44E and 44F, has a width S, and is rotated by a bucket cylinder 45.

The hydraulic excavator according to the present embodiment has the above-described configuration, and its basic operation is not particularly different from that of the prior art.

According to the present embodiment, the maximum movement position of the left side of the bucket 44 is
E and the inner side surface 2A of the crawler belt 2 on the left side are set as positions substantially linearly aligned, and the maximum movement position on the right side is determined by the bucket 44.
Is set so that the right side cutter 44F and the inner side surface 3A of the right crawler belt 3 are arranged substantially linearly, so that the offset amount D of the bucket 44 is set to a range substantially corresponding to the interval W between the crawler belts 2 and 3. It can be set smaller than in the prior art, and this offset amount D can be adapted to the range of use at the actual work site.

Thus, the upper boom 35 and the link 4
The length of 0 and the like can be made short, and a small offset cylinder 37 with a reduced stroke, expansion and contraction force, for example, can be used, so that excessive performance is not given to the working device 31 as in the prior art. It is possible to reduce the weight and cost of the working device 31 while sufficiently securing the performance within a practical range.

The upper boom 35 is connected to the lower boom 32.
And the arm stay 38 is shorter than the arm stay 38, so that the offset amount D of the bucket 44 can be appropriately suppressed by making the length dimension LA smaller.
The arm stay 38 can be formed as long as the length of the upper boom 35 shortened, and the total dimension LT of the upper boom 35 and the arm stay 38 can be formed to be substantially the same as that of the prior art. In the excavation work, the same excavation depth as the related art can be secured.

Moreover, the length LA of the upper boom 35
For example, when digging a groove on the left side, as shown in FIG. 3, the upper boom 35 swings at a position away from the groove, and the arm stay 38 is parallel to the groove along the groove from the tip side. Therefore, a sufficient distance can be secured between the upper boom 35 and the steel plate 24 during excavation work, and the operator of the excavator can perform the digging without paying extra attention to the contact and the like. Etc. can be performed smoothly.

Next, FIGS. 6 and 7 show a second embodiment according to the present invention.
The embodiment of the present invention, the feature of the present embodiment, the maximum movement position of the upper boom, not only the positional relationship with the crawler,
The configuration is also set according to the positional relationship with the cab. Note that, in the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 51 denotes a working device 3 according to the first embodiment.
In the working device used in place of 1, the working device 51 is
Similar to the first embodiment, the lower boom 52, upper boom 53, offset cylinder 54, arm stay 55, link 56, arm 57, arm cylinder 58,
The bucket 59 includes a bucket cylinder 60. The upper boom 53 is formed shorter than the conventional art, and the arm stay 55 is formed longer.

The bucket 59 has a bottom plate 59A,
Left and right side plates 59B, 59C and excavating claws 59D, 59
, And left and right side cutters 59E and 59F. However, in the present embodiment, the width dimension S ′ of the bucket 59 is formed larger than the width dimension S of the bucket 44 used in the first embodiment.

As shown in FIG. 6, the maximum movement position of the left side (one side) of the bucket 59 is substantially the same as that of the first embodiment, and the left side cutter 59E and the inner side surface 2A of the left crawler belt 2 are provided. Are set in advance as positions that are arranged substantially linearly.

On the other hand, the maximum movement position on the right side (other side) of the bucket 59 is set to a position different from that of the first embodiment because the width dimension S is formed large. That is, for example, the right side cutter 59F of the bucket 59
When the position at which the right side of the crawler belt 3 and the inner side surface 3A of the right crawler belt 3 are lined up is set as the maximum movement position, when the working device 51 is raised from the excavation position to the turning position, the left side cutter 59E of the bucket 59 is moved. Will interfere with the cab 6.

For this reason, in this embodiment, the bucket 5
The maximum movement position on the right side of the cab 9 is set as a position where the left side cutter 59E is slightly away from the right side portion 6A of the cab 6 to the right side as shown in FIG. This allows
In a state where the bucket 59 is at the maximum movement position on the right side, it is possible to smoothly raise the working device 51 from the excavation position to the turning position via the right side of the cab 6 in substantially the same manner as in the first embodiment. it can.

At the maximum movement position, the right side cutter 59F of the bucket 59 is disposed at a position slightly overlapping with the crawler belt 3 on the right side.
Excavation range substantially corresponding to the interval W can be secured.

Thus, also in the present embodiment configured as described above, it is possible to obtain substantially the same operation and effect as in the first embodiment. In the present embodiment, in particular, the maximum movement position on the right side of the bucket 59 is set as a position where the left side cutter 59E is slightly away from the right side surface portion 6A of the cab 6 to the right side. Even when the 59 is used, the offset amount can be set to a small value corresponding to the actual use range, and the work device 51 can smoothly perform the elevating operation and the like.

In each of the above embodiments, the cab 6 is disposed on the left side of the vehicle body, and the working devices 31 and
Although the configuration is such that 51 is arranged, the present invention is not limited to this,
The cab 6 may be arranged on the right side of the vehicle body, and the working devices 31 and 51 may be arranged on the left side of the cab 6.

Further, in the embodiment, the cab type excavator in which the driver's seat is provided in the cab 6 has been described as an example. However, the present invention is not limited to this, and the driver's seat is covered by a canopy. It may be applied to a canopy type excavator.

Further, in the embodiment, the ultra-small turning type hydraulic excavator has been described as an example of the offset boom type construction machine. However, the present invention is not limited to this, and is applicable to, for example, medium-sized and large-sized hydraulic excavators. Of course you can.

[0064]

As described above in detail, according to the first aspect of the present invention, the position where the left side surface of the bucket is substantially linearly aligned with the inner side surface of the crawler belt is defined as the leftmost maximum movement position, and the right side surface of the bucket. The maximum movement position on the right is the position that is almost linearly aligned with the inner surface of the crawler belt, so the offset amount when the bucket is moved between the left and right maximum movement positions is set to the interval between each crawler belt. The corresponding range can be set smaller than that of the prior art, and this offset amount can be adapted to the range of use at the actual work site. As a result, for example, the length of the upper boom, link, etc. can be reduced, and a small offset cylinder can be used. It is possible to reduce the weight and cost of the working device while ensuring a sufficient range.

According to the second aspect of the present invention, the position where one side surface of the bucket is substantially linearly arranged with respect to the inner surface of the crawler belt is set as the maximum movement position on one side, and one side surface of the bucket is moved from the cab or canopy. Since the position slightly apart is set as the maximum movement position on the other side, even when, for example, a bucket having a large width is used, the offset amount can be set to a small value corresponding to the actual use range, and the weight of the working device is reduced. ,
The cost can be reduced, and the bucket can be prevented from interfering with the cab or the canopy when the working device is largely raised, for example, and the lifting operation can be performed smoothly.

According to the third aspect of the present invention, since the upper boom is formed to be shorter than the lower boom and the arm stay, the upper boom can be made shorter and the offset amount of the bucket can be appropriately suppressed, and the upper boom and the arm can be appropriately controlled. The sum of the lengths of the stays can be set to a size substantially equal to that of the related art, and the same excavation depth as that of the related art can be secured in the excavation work such as trenching. In addition, by making the length of the upper boom small, for example, when performing a trenching operation while the upper boom is rocked left and right, the upper boom is rocked left and right at a position away from the ground. Therefore, it is possible to secure a sufficient distance between the upper boom and the obstacle on the ground side during the excavation work, and it is possible to smoothly perform digging and the like.

[Brief description of the drawings]

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

FIG. 2 is a plan view showing the excavator in FIG.

FIG. 3 is a left side view of the hydraulic excavator showing a state in which a bucket is offset to a maximum movement position on a left side to perform a trenching operation.

FIG. 4 is a left side view of the hydraulic excavator showing a state in which the bucket is offset to a maximum movement position on the right side to perform a trenching operation.

FIG. 5 is a front view of the hydraulic excavator showing a state in which the working device is raised from the excavation position to the turning position while holding the bucket at the maximum movement position on the right side.

FIG. 6 is a left side view showing a state in which a bucket of a hydraulic shovel according to a second embodiment of the present invention is offset to a leftmost maximum movement position.

FIG. 7 is a left side view showing a state where the bucket in FIG. 6 is offset to a maximum movement position on the right side.

FIG. 8 is a front view showing a conventional hydraulic excavator.

FIG. 9 is a plan view showing the excavator in FIG. 8;

FIG. 10 is a left side view showing a state in which the bucket of the conventional hydraulic excavator is offset to the leftmost maximum movement position.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower traveling body 2, 3 Crawler belt 2A, 3A inner surface 4 Upper revolving body 5 Revolving frame 6 Cab 6A Right side part 7 Building cover 8 Counter weight 31 Work device 32, 52 Lower boom 34 Boom cylinder 35, 53 Upper boom 36 Upper boom connecting pin 37 , 54 Offset cylinder 38, 55 Arm stay 39 Arm stay connecting pin 40, 56 Link 41, 57 Arm 42 Arm connecting pin 43, 58 Arm cylinder 44, 59 Bucket 44A, 59A Bottom plate 44B, 44C, 59B, 59C Side plate 44E, 44F , 59E, 59F Side cutter 45, 60 Bucket cylinder

Claims (3)

[Claims] An undercarriage provided with crawler tracks on both the left and right sides, an upper revolving body pivotally mounted on the undercarriage, and a work mounted on a front side of the upper revolving body. A lower boom which is mounted on the upper revolving unit so that the base end side can be raised and lowered in an upward and downward direction, and which is operated by a boom cylinder, and which swings left and right in the distal end side of the lower boom. An upper boom movably mounted and operated by an offset cylinder, an arm stay slidably mounted on the distal end of the upper boom in a left and right direction and held substantially parallel to the lower boom by a link; An arm which is mounted on the distal end side so as to be able to move upward and downward and which is operated by an arm cylinder, and which is mounted on the distal end side of the arm and which is operated by a bucket cylinder. In an offset boom type construction machine including a bucket, the working device is configured such that when the upper boom swings leftward by an offset cylinder and the bucket moves to the left, the left side surface of the bucket is on the inner side surface of the crawler belt. When the upper boom swings rightward and the bucket moves rightward, the right side of the bucket is substantially straight with respect to the inner surface of the crawler belt. An offset boom type construction machine characterized in that the positions arranged in a line are the maximum movement position on the right side. 2. A lower traveling body provided with crawler tracks on both the left and right sides, and a cab or canopy mounted on the lower traveling body so as to be pivotable and having a driver's seat on one side in the left and right directions. An upper revolving body, and a working device attached to a front side of the upper revolving structure, wherein the working device is attached to the upper revolving structure so as to be able to move upward and downward in the upper revolving structure, and is provided with a boom cylinder. A lower boom to be actuated; an upper boom slidably mounted on the distal end side of the lower boom in a left and right direction and operated by an offset cylinder; and a link mounted on the distal end side of the upper boom slidably in a left and right direction. An arm stay which is held substantially parallel to the lower boom by the arm stay, and an arm which is mounted on the distal end side of the arm stay so as to be able to move up and down and is operated by an arm cylinder; An offset boom type construction machine comprising: a bucket mounted on a tip end of the arm and operated by a bucket cylinder; wherein the working device is configured such that the upper boom swings to one side in the left and right directions by an offset cylinder. The position where one side of the bucket is substantially linearly aligned with the inner surface of the crawler belt when moving to one side is the maximum movement position on one side, and the upper boom swings to the other side in the left and right directions. When the bucket moves to the other side, a position where one side surface of the bucket is slightly away from the cab or canopy is set as a maximum movement position on the other side. 3. A lower traveling body provided with crawler tracks on both the left and right sides, an upper revolving body pivotally mounted on the lower traveling body, and a work attached to a front side of the upper revolving body. A lower boom which is mounted on the upper revolving unit so that the base end side can be raised and lowered in an upward and downward direction, and which is operated by a boom cylinder, and which swings left and right in the distal end side of the lower boom. An upper boom movably mounted and operated by an offset cylinder, an arm stay slidably mounted on the distal end of the upper boom in a left and right direction and held substantially parallel to the lower boom by a link; An arm which is mounted on the distal end side so as to be able to move upward and downward and which is operated by an arm cylinder, and which is mounted on the distal end side of the arm and which is operated by a bucket cylinder. An offset boom type construction machine comprising a bucket, wherein the upper boom is formed to be shorter than the lower boom, and the upper boom is formed to be shorter than the arm stay.