JP2000328592A - Swivelling working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of unexcavated portion by making offset the widthwise center line of arm and bucket to an offset member mounting side with respect to the widthwise center line of first and second booms under the condition where an excavation working machine is directed forward/rearward. SOLUTION: A first boom 10 is mounted to a turning base of an excavation working machine so as to move up and down freely in the forward and rearward direction, and to a tip of the first boom 10 a second boom 11 is mounted so as to be turnable right and left freely. To the second boom 11 a third boom 12 is mounted so as to be turnable right and left freely, and to the third boom 12 an arm 13 having a bucket 14 at its tip is mounted so as to be turnable up and down freely. To the center line 20 of the boom 10 and the boom 12 the lateral center line 21 of an arm cylinder 17 and the bucket 14 are arranged in an offset manner only by a distance Y to the side of offset rod 30 and offset cylinder 31. Accordingly, a stay 23 pivotally supporting the rod 30 is prevented from abutting on a groove or the like and being damaged thereby, and generation of unexcavated portion can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the technology of a turning work machine such as a backhoe.

[0002]

2. Description of the Related Art Heretofore, a swivel frame has been rotatably supported in a horizontal direction above a traveling device such as a crawler type traveling device, and an operating unit has been mounted on the upper left and right sides of the swivel frame. The engine, fuel and working oil tanks and the like are mounted from the side to the rear of the operation unit and are covered by a hood. Further, an excavating work device is arranged on the lateral side of the driving unit, and as shown in FIG. 15, the base of the first boom 90 of the three divided booms of the excavating work device is vertically rotatable. The second boom 91 is attached to the tip of the first boom 90 so as to be able to turn left and right, and the third boom 92 is attached to the tip of the second boom 91 so as to be able to turn left and right.
A bucket 9 which is a work equipment attachment via an arm 93 attached to the distal end of the third boom 92 so as to be vertically rotatable.
4 are connected so as to be able to move up and down. An offset cylinder 95 is interposed between the first boom 90 and the third boom 92, and both ends of an offset rod 96 are pivotally connected therebetween, so that the first boom 90, the second boom 91, and the third boom 92 And the offset rod 96 constitute a parallel quadruple link.

When the second boom 91 is rotated left and right by the expansion and contraction drive of the offset cylinder 95, the arm 93 and the bucket 94 are offset left and right (eccentric) while being kept in the front-rear direction, and the traveling direction of the body In order to improve the weight balance of the excavating device, a technique of offsetting the tip of a first boom has been known. For example, this is the technique of Japanese Utility Model No. 2563574.

In a backhoe or the like having an earthing plate, one hydraulic cylinder is arranged between a body frame supporting a track frame of a crawler type traveling device and the earthing plate so that the earthing plate can be moved up and down. FIG. 16 shows a mounting structure of a discharge plate that can be moved up and down by one hydraulic cylinder.
As shown in FIG. 17, the earth discharging plate 3 has push frames 43, 43 projecting rearward from both sides thereof in parallel, and the ends of the push frames 43, 43 are pivotally supported on both sides of the body frame so as to be vertically rotatable. I do. Then, two bracket plates 39, 39 are projected in parallel in the middle of the vertical direction at the left and right centers of the back surface of the dump plate, and provided on the bottom side of the dump plate lifting cylinder 55 on the bracket plates 39, 39. The clevis 40 is pivotally supported by a pin so as to be vertically rotatable, and the rear end of the piston rod of the cylinder for lifting and lowering the earthing plate is pivotally supported by a frame projecting forward from the body frame so as to be vertically rotatable.

[0005]

However, in the prior art, the offset rod 96 and the first boom 90 are used to form an offset member mounting portion, that is, a parallel link.
And the portion connecting the offset rod 96 and the offset cylinder 95 are the first boom 90
Or, it protrudes sideways from the third boom 92. Therefore, in digging work, when excavating the vicinity of the sheet pile 98 driven into the earth, the offset member mounting portion may hit the sheet pile 98, and the excavation member may not be able to excavate to the last minute, or the connecting portion may be damaged. Was given. That is, in general, it is difficult to drive a sheet pile straight and vertically, but it is driven with a slight inclination, and may be inclined by a load of a retaining wall. Therefore, even when the offset member attaching portion is located inside the side surface of the bucket, it may hit when actually digging.

[0006] In addition, the structure in which the bottom side of the bracket elevating cylinder is attached to the bracket plate of the earthing plate attaching portion is as follows.
Since two bracket plates were attached to the earth discharging plate and one clevis was inserted and pivoted, when the earth discharging operation was performed, as shown in FIG. The soil that has climbed over is clogged or accumulated in the connecting portion between the bracket plates 39 and the discharging plate lifting cylinder 55.

[0007] The accumulated soil falls due to vibration during traveling after completion of the work. However, when the excavation work is completed, the soil is backfilled and leveled. As a result, the soil accumulated in the connecting portion is scattered on the pavement road surface, and the road surface is soiled. In such a case, in the past, it has been manually cleaned by a broom or the like. It took time and labor to clean up the scattered soil, which was a tedious task. It is also possible to provide a cover so that the soil does not accumulate, but this has been costly.

[0008]

According to the present invention, in order to solve the above-mentioned problems, according to the first aspect, a boom which is vertically rotatably mounted on a side of a driving unit on a swivel base is provided. A boom, a second boom attached to the tip of the first boom so as to be rotatable in the left-right direction, and a third boom attached to the tip of the second boom so as to be rotatable in the left-right direction, In addition to being configured so that it can be offset in the left and right direction,
In a turning work machine having an excavating work device in which a bucket is mounted via an arm vertically rotatably attached to the tip of the third boom, the first boom and the second boom are arranged with the excavating work device facing in the front-rear direction. The center line in the width direction of the arm and the bucket is offset toward the mounting side of the offset member with respect to the center line in the width direction.

According to a second aspect of the present invention, the third boom and the second boom are pivotally supported by widening the lateral width of the third boom on the second boom side and offsetting the third boom to the side opposite to the side where the offset member is mounted. A rotating shaft is provided.

According to a third aspect of the present invention, the left and right widths of the third boom on the arm side are widened and offset to the same side as the mounting side of the offset member, and the arm is attached to the tip of the third boom. .

According to a fourth aspect of the present invention, a boom which is vertically rotatably attached to a side of the driving unit on the swivel base is provided with a first boom and a left and right pivotable at a tip end of the first boom. A second boom attached to the and the third boom attached to the tip of the second boom so as to be rotatable in the left-right direction, and configured to be offset in the left-right direction,
In a turning work machine having an excavating work device in which a bucket is mounted via an arm vertically rotatably attached to the tip of the third boom, a mirror is provided so as to be position-adjustable on the main body side of the second boom side of the third boom. It is provided.

According to a fifth aspect of the present invention, there is provided a construction in which the traveling equipment of the turning work machine is provided with a placing and discharging plate, and the discharging plate is driven up and down by one hydraulic cylinder. One of the bracket plates is protruded, and a lifting plate lifting cylinder is connected between the bracket plate and the body frame via a bifurcated clevis.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The problems and configurations to be solved by the present invention are as described above. Next, embodiments of the present invention shown in the accompanying drawings will be described. 1 is an overall side view of a backhoe as a turning work machine, FIG. 2 is an overall plan view of the same, FIG. 3 is a plan view of an excavating work apparatus capable of offsetting the front and rear axes of an arm and a bucket, and FIG. FIG. 5 is a plan view of a third boom in another form of offset, FIG. 6 is a rear view thereof, and FIG. 7 is a plan view of a drilling work apparatus in another form of offset. 8 is a front view showing the same working state, FIG. 9 is a plan view of an excavating work apparatus showing another embodiment of the third boom, and FIG. 10 is a side view of the backhoe with a mirror attached to the side of the main body of the boom at the time of working. , FIG. 11 is an exploded perspective view of the bracket plate and the earthing plate lifting cylinder of the present invention, FIG. 12 is a side view of the assembled state, FIG. 13 is a plan view of the same, and FIG. FIG.

Referring to FIGS. 1 and 2, the structure of the turning work machine of the present invention will be described. A swivel 4 is attached to the upper part of the traveling device 1 equipped with a pair of left and right crawler traveling devices so as to be able to turn, and a driver's seat 6 is arranged on one side of the upper part of the swivel 4. Is covered with a canopy, etc.
The excavation work device 5 is arranged on the side of the operation unit 9. A battery, an engine, and the like (not shown) are provided at the rear of the operation unit 9 and are covered with a cover 63. Also,
At the front end of the traveling device 1, a discharge plate 3 described later is mounted.

The excavating work apparatus 5 lifts the first boom 10 to the maximum, and rolls the arm 13 and the bucket 14 to the maximum without offsetting the arm 13 and the bucket 14 to the left and right (the state shown in the two-dot chain line in FIG. 1). Is configured such that the whole can be stored within the turning diameter of the turning table 4. The bucket 14 and the operating unit 9 are configured so as not to interfere with each other in the small turning storage state in which the entire excavation work device 5 is stored within the turning radius of the turning table 4.

Next, the excavator 5 will be described.
The excavation work device 5 includes a first boom 10 attached to the swivel table 4 so as to be vertically rotatable in a front-rear direction, and a second boom 1 attached to a distal end of the first boom 10 so as to be rotatable in a left-right direction.
1, a third boom 12 attached to the second boom 11 so as to be rotatable in the left-right direction, an arm 13 attached to the third boom 12 so as to be rotatable in the vertical direction, and a tip of the arm 13. It has a bucket 14 as an attached work attachment, and is configured so that the arm 13 and the bucket 14 can be offset in the left-right direction by rotating the second boom 11 in the left-right direction.

Then, a boom cylinder 29 is interposed between the first boom 10 and the swivel base 4, and the boom cylinder 2
9, the first boom 10 can be turned up and down, and an arm cylinder 17 is provided between the third boom 12 and the arm 13.
The arm 13 is vertically rotatable by the expansion and contraction of the arm cylinder 17. A bucket cylinder 48 is interposed between the arm 13 and the bucket 14, and the bucket 14 is expanded and contracted by the bucket cylinder 48. It can be turned up and down.

As shown in FIG. 3, the second boom 11 is rotatably connected to the upper end of the first boom 10 at its base end by a lower turning shaft 15 so as to be rotatable left and right. The part connects the third boom 12 to the left and right sides freely by the upper rotation shaft 16, and a stay 23 serving as an offset member mounting portion is protruded from the third boom 12 on the left side of the second boom 11. A stay 2 is pivotally supported by the stay 23 at the distal end of the piston rod 31 a of the offset cylinder 31 and the front end of the offset rod 30, and protrudes from the base side of the second boom 11.
6, the bottom side of the offset cylinder 31 is pivotally supported, and the rear part of the offset rod 30 is pivotally connected to a stay 24 protruding leftward from the tip of the first boom 10, and the offset rod 30, the first boom 10, The two booms 11 and the third boom 12 constitute a parallel quadruple link mechanism.

The bucket 14 is rotated in the left-right direction with respect to the first boom 10 by extending and contracting the offset cylinder 31. In this case, the parallel quadruple link mechanism allows the bucket 14 to be viewed from the front or the rear. First boom 10, third boom 12, arm 13, and bucket 1
The angle with 4 does not change and is offset while maintaining the parallel state, thereby enabling the trench to be dug.

As shown in FIG. 3, according to the present invention, when the second boom 11 is oriented in the front-rear direction, the arm 13 and the arm 13 are positioned with respect to the left and right center lines 20 of the first boom 10 and the second boom 11. The left and right center lines 21 of the cylinder 17 and the bucket 14 are offset by a distance Y on the arrangement side of the offset rod 30 and the offset cylinder 31 serving as offset members. That is, in order to offset as described above, the second boom 11 side of the third boom 12, that is, the rear upper portion of the right side plate is bent outward (to the right in the drawing), and the left and right width of the rear portion 12 a of the third boom 12 is adjusted. Are swollen to the right side and widened, and pivot bosses 17a projecting from the front side of the cylinder case of the arm cylinder 17 to the rear portion 12a are supported rotatably by a pivot shaft 41. I have. Therefore, the right and left center positions can be offset by a simple design change that changes the shape of the right side plate for manufacturing the third boom 12. Below this position, the upper rotating shaft 16 pivotally supported by the tip of the second boom 11
, And is offset by a distance Y between the center of the upper rotation shaft 16 and the axis of the arm cylinder 17.

In this connection configuration, the offset rod 3 can be turned left and right as in the prior art.
If the distance between the axis of the pivot shaft 32 for pivotally supporting the zero and offset cylinder 31 and the stay 23 and the axis of the upper rotation shaft 16 is the same as that of the related art, the stay 23 becomes the third boom 12. The length projecting more laterally becomes shorter than before. Therefore, the distance X between the front-rear extension line of the left end of the bucket 14 and the left end of the stay 23 is longer than the conventional length X ″ (FIG. 15). When performing grooving work, the sheet pile 25
Is slightly inclined toward the fuselage (excavation side),
Can excavate without touching the sheet pile 25.

Also, as shown in FIG.
In the same manner as described above, it is also possible to arrange an offset arrangement in a turning work machine of another form in which 2 'is configured to be long and deep digging is enabled. In this case, in FIG. 7, a stay 24 'is protruded to the left from the tip of the first boom 10', and the stay 24 '
Offset rod 30 'and offset cylinder 31'
, The tip of the offset rod 30 'is protruded leftward from the rear side surface of the third boom 12'.
The tip of the piston rod 31a 'of the offset cylinder 31' is pivotally supported by a stay 38 projecting leftward from the side surface of the second boom 11.

As shown in FIGS. 5 and 6, the third boom 12 'is closer to the second boom 11', that is, the lateral width at the rear is wider than the lateral width at the front, and the third boom 12 ' The right rear side plate is expanded so as to protrude rightward. In the widened rear portion 12a ', the upper rotation shaft 16 is disposed on the extension of the left and right center line 20' of the second boom 11 ', and the left and right center lines 21' of the arm 13 ', the arm cylinder 17', and the bucket 14 '. The left and right center line 2
The offset rod 30 and the offset cylinder 31 are attached to the mounting side (offset member mounting portion side) by a distance Y from 0 ′.

The left and right lengths of the boss 33 for supporting the bottom side of the arm cylinder 17 'are increased, and the pivot position of the arm cylinder 17' is arranged on the left and right center line 21 '. Further, in order to perform the offset rotation as in the conventional case, the offset rod 3 connected to the stay 23 'is used.
If the distance between the center of the pivot shaft at the end of the 0 'tip and the center of the upper rotation shaft 16 is the same as in the related art, the length of the stay 23' protruding from the rear left side of the third boom 12 'can be shortened. .

Therefore, as shown in FIG. 7, when the offset cylinder 31 is driven to expand and contract to rotate the tip end side of the second boom 11 to the left and right, and especially to the left, the stay 2
Since there is a distance X 'between the left end of 3' and the left end of the bucket 14, the stay 23 'does not come into contact with the sheet pile 25 in the side groove excavation work. It is possible to improve workability without leaving any digging.

Further, the third boom 12 'may be configured as shown in FIG. 9 so that the distance between the left end of the bucket 14 and the left end of the offset member mounting portion can be increased. That is, the offset member and the rear part of the third boom 12 'have the same connection configuration as the conventional one, and the left and right widths of the arm 13 side of the third boom 12', that is, the front part, are expanded to the left and widened. Therefore, the arm 13 'and the bucket 14' can be offset to the left by the distance Y, and the distance X 'between the left end of the bucket 14' and the left end of the stay 23 can be increased. Note that arm cylinder 1
The mounting portion on the base side of 7 'also needs to be offset.

Further, in the present invention, as shown in FIG. 10, a mirror 34 is disposed on the main unit side (concave side) of the base (second boom 11 side) of the third boom 12 '. 1
In the working machine of the embodiment, the lower part (concave side) of the first boom 10 or the lower part of the third boom 12 is disposed),
The mirror 34 is composed of a convex mirror so that the mirror can be seen widely, and the mounting portion can be adjusted vertically and horizontally, and is arranged at a position where it does not interfere when left and right offset. And it is arrange | positioned in the position directly visible from the operator who sat in the driver's seat 6. With this configuration, when a deep hole is excavated, the operator cannot see below the Z line connecting the operator's eyes and the tip of the ground surface in FIG. It was located on the side or ahead, signaling the operator to indicate the excavation position and working direction. Therefore, a plurality of workers were required, and if communication was not successful, the work did not proceed smoothly.

By arranging the mirror 34 as in the present invention, it is possible to see from the side wall in front of the hole to the deepest part of the hole, so that the operator can directly grasp the working state and improve workability. You can do it. Since the mirror 34 is provided at the base of the third boom 12 ′, as shown in FIG. 8, when the work is offset to the left, the mirror 34 is located just in front, and the work is easy. When offset to the right, the first boom 10 'and the second boom 11' are formed in a "-" shape in plan view so that they do not become blind spots, and the third boom 12 'moves in parallel. Therefore, it is not necessary to adjust the angle or position of the mirror 34, and it is possible to view the image at any position.

Next, the mounting structure of the earth discharging plate 3 will be described with reference to FIGS. In FIG. 11, left and right track frames 53 supporting the traveling device 1 are connected to and supported by a body frame 54, and an opening 54a for supporting a swivel joint is formed at the center of the body frame 54, A support bracket 54b protrudes rearward from the left and right center of the rear surface of the frame 54, and the support bracket 54b
The piston rod 55a of the earth-discharge plate elevating cylinder 55 is pivotally supported so as to be vertically rotatable.

Further, support side brackets 54c are provided on both sides of the support bracket 54b. The rear ends of the pushing frames 43 provided on the support side brackets 54c in parallel with the earth discharging plate 3 are provided. Be pivoted. The middle part of the push frames 43 is connected and fixed by a connection frame 43a. A bracket plate 44 projects from the back of the earthing plate 3 between the push frames 43 and the mounting base, and the bottom side of the earthing plate lifting / lowering cylinder 55 is pivotally connected to the bracket plate 44.

As shown in FIGS. 11 and 13, a forked clevis 35 is provided on the bottom side of the earthing plate lifting cylinder 55, and the bracket plate 44 is inserted into the forked clevis 35 and pivoted by a pin 36. The pin 36 is fixed to the bifurcated clevis 35 by a bolt 37 with a mounting plate 36a fixed to the end.

The bracket plate 44 is formed of a single plate, and as shown in FIG. 14, the upper surface has an inverted V-shape or a mountain shape, and the upper surface has a shape in which soil or the like is unlikely to accumulate. As shown in FIG. 12, the position in the front-rear direction of the pin hole 44a for pivotally supporting the cylinder 55 is set at a position away from the rear surface of the earth discharging plate 3 by a distance L from the upper surface of the earth discharging plate 3 during the earth discharging operation. The position is such that the soil that has climbed over does not directly rest on the pivot 26.

Further, the vertical position of the pin hole 44a is set to a length H from the lower end of the earth discharging plate 3, and the height H is set to the height H.
To almost the same height as In this embodiment, the position is slightly lower than the upper end of the earth discharging plate 3, but it is preferable that the position is higher than the upper end. Therefore,
The soil that has climbed over the upper surface of the earth removal plate 3 during the earth removal operation hardly climbs over the pivotal joint 46 located at substantially the same height behind it.

With this configuration, even when soil is passed over the upper end of the earth discharging plate 3 when the earth discharging work is performed by the earth discharging plate 3, only one bracket plate 44 is provided.
Since the upper surface has a mountain shape, the soil that has climbed over hardly accumulates on the upper surface and falls quickly due to vibration or the like. Further, since the pivot portion 46 is located at a high position behind the earth removal plate 3, the soil that has climbed over the earth removal plate 3 is removed by the pivot portion 4.
6, and even if soil accumulates on the pivot portion 46, the bracket plate is one instead of two and the area of the upper surface of the forked clevis 35 is small, as in the conventional case. In addition, the amount of accumulation is small, it can be easily dropped by vibration, vertical movement, etc., and the amount of clearing even if it falls on the road surface is small.

[0035]

As described above, the present invention has the following advantages. That is, as in claim 1,
A first boom, a second boom rotatably attached to the tip of the first boom in the left-right direction, A third boom attached to the end of the second boom so as to be rotatable in the left-right direction, configured to be offset in the left-right direction, and a bucket via an arm attached to the tip of the third boom so as to be vertically rotatable; In the turning work machine having the excavating work device equipped with the arm, the width direction center line of the arm and the bucket is offset with respect to the width direction center line of the first boom and the second boom in a state where the excavating device is oriented in the front-rear direction. Since the offset member is offset to the mounting side of the member, the offset member mounting portion is located inside the left and right width of the bucket, and when excavating by inserting the bucket into a groove or the like, the offset member is Without damage spans when the sheet pile or the like used as Yamadome when the groove or grooves construction urging portion took digging, it is possible to take dug by inserting the bucket deeper. In addition, the bucket can be dug reliably to the corner on the support side of the offset rod at the bottom of the groove, leaving no digging left, so that there is no need for the worker to go down into the groove and manually dig it. Performance can be improved.

According to the second aspect of the present invention, the third boom and the second boom are pivotally supported by widening the lateral width of the third boom on the second boom side and offsetting the third boom to the side opposite to the mounting side of the offset member. Since the rotating shaft is provided, only the members for pivotally supporting the third boom and the second boom and the side plate on one side of the third boom need to be changed. No change and minimal cost increase.

According to the third aspect of the present invention, the left and right widths of the third boom on the arm side are widened and offset to the same side as the mounting side of the offset member, and the arm is attached to the tip of the third boom. It can be easily manufactured only by changing the vertical rotation part, and it is not necessary to change the offset member and its mounting portion, so that it can be used as it is conventionally, and retrofitting can be easily performed.

According to a fourth aspect of the present invention, a boom mounted to be rotatable up and down on the side of the driving unit on the swivel base is rotatable in the left-right direction on the first boom and the tip of the first boom. A second boom attached to the and the third boom attached to the tip of the second boom so as to be rotatable in the left-right direction, and configured to be offset in the left-right direction,
In a turning work machine having an excavating work device in which a bucket is mounted via an arm vertically rotatably attached to the tip of the third boom, a mirror is provided so as to be position-adjustable on the main body side of the second boom side of the third boom. Since it is provided, when drilling, it is possible to see from the driver's seat through the mirror to the deepest part of the hole from the front side wall, and the operator can directly grasp the work state without asking other workers' instructions And workability can be improved.

According to a fifth aspect of the present invention, there is provided a construction in which the traveling equipment of the turning work machine is provided with a grounding plate and the lifting plate is driven up and down by one hydraulic cylinder. One more bracket plate is protruded, and a lifting plate elevating cylinder is connected to the bracket plate and the body frame via a bifurcated clevis, so that discharging is performed as in the conventional case with two bracket plates. It becomes difficult for the soil that has climbed over the board to accumulate, the amount of accumulation at the joint between the bracket plate and the clevis decreases, and the accumulated soil hardly falls when traveling on the pavement after work.
With a simple structure, the cleaning work can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall side view of a backhoe as a turning work machine.

FIG. 2 is an overall plan view of the same.

FIG. 3 is a plan view of a digging operation device capable of offsetting front and rear axes of an arm and a bucket.

FIG. 4 is a side view of a turning work machine having an excavating work device of another form of offset.

FIG. 5 is a plan view of a third boom having another form of offset.

FIG. 6 is a rear view of the same.

FIG. 7 is a plan view of an excavating work device having another form of offset.

FIG. 8 is a front view showing the working state.

FIG. 9 is a plan view of an excavating work device showing another embodiment of the third boom.

FIG. 10 is a side view at the time of operation of a backhoe in which a mirror is attached to the side of the main unit of the boom.

FIG. 11 is an exploded perspective view of a bracket plate and a discharge plate lifting cylinder according to the present invention.

FIG. 12 is a side view of the same assembled state.

FIG. 13 is a plan view of the same.

FIG. 14 is a sectional view taken along line WW in FIG.

FIG. 15 is a plan view of a conventional excavation work device.

FIG. 16 is an assembled perspective view of a conventional bracket plate and a dump plate lifting cylinder.

FIG. 17 is a side view showing the same working state.

[Explanation of symbols]

 REFERENCE SIGNS LIST 4 swivel base 5 excavation work device 9 operating unit 10 first boom 11 second boom 12 third boom 13 arm 14 bucket 23 stay 30 offset rod 31 offset cylinder 34 mirror

Claims (5)

[Claims] 1. A first boom, which is rotatably mounted on a side of an operating unit on a swivel table, and a second boom which is rotatably mounted on a distal end of the first boom in a lateral direction. A boom and a third boom attached to the tip of the second boom so as to be rotatable in the left-right direction, and configured to be offset in the left-right direction, and attached to the tip of the third boom so as to be able to rotate up and down. In a turning work machine having an excavating work device mounted with a bucket via an arm, with the excavating work device facing in the front-rear direction, the width of the arm and the bucket with respect to the center line in the width direction of the first boom and the second boom. A turning work machine characterized in that a direction center line is offset to a mounting side of an offset member. 2. A rotation shaft for pivotally supporting the third boom and the second boom is provided by widening the lateral width of the third boom on the second boom side and offsetting the third boom to the side opposite to the mounting side of the offset member. The turning work machine according to claim 1, wherein: 3. An arm is attached to the tip of the third boom by widening the left and right widths of the third boom on the arm side, offset to the same side as the attachment side of the offset member. Turning work machine. 4. A first boom, which is rotatably attached to a side of the driving section on the swivel table, and a second boom which is rotatably attached to a tip end of the first boom in a lateral direction. A boom and a third boom attached to the tip of the second boom so as to be rotatable in the left-right direction, and configured to be offset in the left-right direction, and attached to the tip of the third boom so as to be able to rotate up and down. A turning work machine having an excavating work device mounted with a bucket via an arm, wherein a mirror is provided on the main machine side of the second boom side of the third boom so as to be adjustable in position. 5. A configuration in which the traveling equipment of the turning work machine is provided with a ground removal plate and the lifting plate is driven up and down by one hydraulic cylinder. And a lifting plate lifting cylinder is connected between the bracket plate and the body frame via a forked clevis.