JP2004176388A - Hydraulic cylinder mounting structure for multistage extensible arm, and multistage extensible arm working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the buckling load of a hydraulic cylinder for extending a multistage extensible arm. <P>SOLUTION: In the multistage extensible arm 4 comprising a first arm 41, a second arm 42 and a third arm 43, a rod upper end part 45a of an expansion cylinder 45 is pin-connected to the first arm 41, and a tube upper end part 45b is pin-connected to the second arm 42. The upper end face of the rod upper end part 45a is provided with a buckling preventive plate 470 projecting in the longitudinal direction, and both sides of the buckling preventive plate 470 are clamped by presser plates 471, 472. In the clamped state of the buckling preventive plate 470, the presser plates 471, 472 are fixed to a screw seat 41h of the first arm 41 through bolts 475 passing through the presser plates 471, 472. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydraulic cylinder mounting structure for extending and retracting a multi-stage telescopic arm and a multi-stage telescopic arm working machine.
[0002]
[Prior art]
2. Description of the Related Art A working machine based on a hydraulic excavator body and provided with a multi-stage telescopic bucket at the end of a boom (hereinafter, a multi-stage telescopic arm working machine) is known (for example, see Patent Document 1). According to this, a three-stage telescopic arm including a first arm (outer arm) connected to the boom, a second arm (intermediate arm) inserted into the first arm, and a third arm (inner arm) inserted into the second arm. The work machine is configured as follows.
[0003]
The second arm and the third arm are connected via a hydraulic cylinder, and a pull-up rope sheave is attached to the tip of the second arm. A pulling rope is wrapped around the pulling rope sheave, and one end thereof is connected to the first arm, and the other end is connected to the third arm in the second arm. When the hydraulic cylinder is expanded and contracted, the third arm expands and contracts with respect to the second arm, and accordingly, the position of the lifting rope sheave moves. As a result, one of the rope length from the pulling rope sheave to the first arm and the rope length from the pulling rope sheave to the third arm increases, and the other decreases, and the second arm expands and contracts with respect to the first arm.
[0004]
[Patent Document 1]
JP 2001-164594 A (full text)
[0005]
[Problems to be solved by the invention]
In the device described in the above-mentioned publication, the rod side and the cylinder tube side of the hydraulic cylinder for extending and retracting the arm are each rotatably pin-connected to the arm. However, since the hydraulic cylinder for expanding and contracting the arm is long, if the hydraulic cylinder is attached by pin connection, rotation displacement is allowed to the cylinder due to the gap of the pin connection, etc., and it is easy to buckle when a compressive load acts on the cylinder .
[0006]
The present invention provides a hydraulic cylinder mounting structure for a multi-stage telescopic arm and a multi-stage telescopic arm working machine that can increase the buckling load of a hydraulic cylinder for expanding and contracting an arm (make it less likely to buckle).
[0007]
[Means for Solving the Problems]
The hydraulic cylinder fixing structure of the multi-stage telescopic arm according to the present invention comprises a multi-stage telescopic arm having a multi-stage telescopic arm, a cylinder rod and a cylinder tube each connected to a different-stage arm, and rotating at least one of the arms. The hydraulic cylinder is characterized by comprising a hydraulic cylinder that movably connects a pin to extend and contract an arm, and a rotation preventing unit that prevents rotation of a pin connecting portion of the hydraulic cylinder.
In addition, the multi-stage telescopic arm working machine according to the present invention includes a traveling body, a revolving body that revolves on the traveling body, a boom that is installed so as to move up and down on the revolving body, and is rotatable around the tip of the boom. And a multi-stage telescopic arm having the above-mentioned hydraulic cylinder mounting structure.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a hydraulic cylinder mounting structure for a multistage telescopic arm according to the present invention will be described with reference to FIGS.
1 and 2 are side views of a multi-stage telescopic arm working machine having a hydraulic cylinder mounting structure according to an embodiment of the present invention. FIG. 1 shows the inspection posture before or after the start of the work, and FIG. 2 shows the work posture. As shown in FIG. 1, the multi-stage telescopic arm working machine uses a hydraulic shovel as a base machine. That is, the arm working machine has a traveling body 1, a revolving body 2 rotatably mounted on the traveling body 1, and a boom 3 rotatably supported on the revolving body 2. A telescopic multi-stage telescopic arm 4 (hereinafter referred to as a telescopic arm) is rotatably supported at the tip end of the boom 3 via an arm cylinder 4a so as to be rotatable in a vertical plane. They are connected by a cylinder 4a. The boom 3 is raised and lowered by the expansion and contraction of the boom cylinder 3a, and the telescopic arm 4 is rotated by the expansion and contraction of the arm cylinder 4a. As shown in FIG. 2, a bucket 5 is attached to the tip of the telescopic arm 4 (the tip of the third arm 43), and excavation work is performed by opening and closing the bucket 5. In the following, the vertical and horizontal directions of the telescopic arm 4 are defined based on the working posture of FIG.
[0009]
The configuration of the telescopic arm 4 will be described. 3 and 4 are side sectional views showing the internal configuration of the telescopic arm 4, and FIG. 5 is a sectional view taken along line VV of FIG. 3 shows a contracted state of the telescopic arm 4, and FIG. 4 shows an extended state. As shown in FIGS. 3 and 4, the telescopic arm 4 includes a first arm (outer arm) 41, a second arm 42 (intermediate arm) inserted into the first arm 41 so as to be telescopic, and a telescopic arm inside the second arm 42. And an inserted third arm (inner arm) 43. Each of the arms 41 to 43 has a substantially rectangular cross section.
[0010]
A bracket 44 is provided on the rear surface of the first arm 41, and the boom 3 and the arm cylinder 4a are rotatably connected to the bracket 44 as shown in FIG. As shown in FIGS. 3 and 4, a bracket 43a for mounting a work attachment is provided at the lower end of the third arm 43, and the bucket 5 shown in FIG. 2 is mounted on the bracket 43a. The bucket 5 is opened and closed by driving a bucket cylinder 5a. The rod-side upper end 45a of the telescopic cylinder 45 is attached to the upper inner side surface of the first arm 41, and the tube-side upper end 45b of the telescopic cylinder 45 is attached to the upper end of the second arm 42. The telescopic cylinder 45 extends through the upper ends of the second arm 42 and the third arm 43 and extends into the arms 42 and 43. Details of the mounting portions 45a and 45b of the telescopic cylinder 45 will be described later.
[0011]
A bracket 42a projects from the upper end of the second arm 42 toward the upper end of the first arm 41, and a sheave rotation shaft 48 is provided on the bracket 42a. As shown in FIG. 5, a pair of pulling sheaves 46 and a pair of hose sheaves 47 juxtaposed inside the pulling sheave 46 are rotatably supported on the rotating shaft 48. The lifting sheave 46 and the hose sheave 47 are provided integrally, and both rotate integrally. The rotation shaft 48 is provided so as to be located substantially at the center of the first arm 41, and the second arm 42 and the third arm 43 are arranged in the first arm 41 in front of each other. The telescopic cylinder 45 passes through substantially the center of the second arm 42 and the third arm 43.
[0012]
A lifting rope 49 is wound around each lifting sheave 46. As shown in FIGS. 3 and 4, these lifting ropes 49 are disposed in the longitudinal direction between the first arm 41 and the second arm 42, pass through the upper end of the second arm 42 via the sheave 46, and It is disposed longitudinally in front of the telescopic cylinder 45 in the arm 42. One end of the pull-up rope 46 is connected to a support portion 41 a at a lower rear portion of the first arm 41, and the other end is connected to an upper end portion 43 b of the third arm 43.
[0013]
Hydraulic hoses 50 for guiding pressure oil from the revolving unit 2 to the buckets 5a are wound around the hose sheaves 47, respectively. The hydraulic hose 50 is disposed between the first arm 41 and the second arm 42 along with the pull-up rope 49, penetrates the upper end of the second arm 42, and is disposed in the second arm 41. One end of the hydraulic hose 50 is connected to the support portion 41a, and the other end is connected to the upper end portion 43b of the third arm. One end of a hydraulic pipe (not shown) is connected to the upper end 43b of the third arm, and the other end of the hydraulic pipe passes through the inside of the third arm 43 and is connected to the bucket cylinder 5a at the lower end of the third arm. Although not shown, a hydraulic pipe is provided from the revolving unit 2 along the boom 3, and the hydraulic pipe is connected to the support 41a. Thereby, the pressure oil from the revolving unit 2 is guided to the bucket cylinder 5 a via the hydraulic hose 50. Also, the pressure oil from the revolving unit 2 is supplied and discharged through an oil supply / drain port 455a (see FIG. 6) at the upper end of the telescopic cylinder 45 via a hydraulic pipe (not shown) disposed in the longitudinal direction on the outer surface of the first arm 41. ).
[0014]
A bracket 42b is fixed to the lower end of the rear surface of the second arm 42, and a pair of push sheaves 52 is rotatably supported by the bracket 42b. Pushing ropes 53 are wound around the pushing sheaves 52, respectively, and one ends of the pushing ropes 53 are respectively connected to support portions 41b provided at the lower end of the rear surface of the first arm 41. The other end of the pushing rope 53 passes behind the telescopic cylinder 45 in the third arm 43 and is connected to the upper end 43 c of the third arm 43. As shown in FIG. 2, an opening 4c is provided at the upper end of the telescopic arm 4 (first arm 41) so that sheaves 46 and 47, a rope 49, and a hose 50 can be visually recognized from the outside.
[0015]
Here, the operation when excavation work is performed by the multistage telescopic arm working machine of the present embodiment will be described.
When performing excavation work, first, the boom cylinder 3a and the arm cylinder 4a are driven to change the posture of the working machine in the state of FIG. 1 to the state of FIG. Next, the telescopic cylinder 45 is extended. With the extension movement of the telescopic cylinder 45, the distance between the pulling sheave 46 and the rope supporting portion 41a is shortened, and the pulling rope 49 is slackened. Thus, the third arm 43 falls by its own weight, one end of the rope 49 is pulled by the third arm 43, and the rope 49 moves along the lifting sheave 46. As a result, as shown in FIG. 4, the rope length from the sheave 46 to the rope support portion 41a decreases, and the rope length from the sheave 46 to the rope support portion 43b increases accordingly. At this time, a tensile force mainly acts on the telescopic cylinder 45.
[0016]
When the third arm 43 extends with respect to the second arm 42, the hose sheave 47 moves downward integrally with the lifting sheave 46. Therefore, the hydraulic hose 50 moves along the hose sheave 47 similarly to the lifting rope 49. Further, the distance between the pushing sheave 52 and the support portions 41b and 43c of the pushing rope 53 also changes as shown.
[0017]
When the bucket 5 reaches the excavation surface, the bucket 5 is driven to open and close the bucket 5, and soil and the like are scooped in the bucket 5. During the excavation work, an excavation reaction force from the ground acts on the bucket 5, and the third arm 43 is pushed upward. Since the upward movement of the third arm 43 is restricted by the pushing rope 53, the upward movement of the third arm 43 is prevented. At this time, a compression force mainly acts on the telescopic cylinder 45.
[0018]
When soil and the like are stored in the bucket 5, the telescopic cylinder 45 is retracted by operating the lever. As a result, the second arm 42 retracts into the first arm 41, and the lifting sheave 46 moves upward accordingly. By this movement, the third arm 43 is pulled up via the pulling rope 49, and the third arm 43 is retracted into the second arm 42 according to the retracted amount of the cylinder 45. At this time, the hose sheave 47 also moves upward together with the lifting sheave 46, and the hydraulic hose 50 moves along the hose sheave 47. When the telescopic cylinder 45 is retracted and the bucket 5 is moved upward, the bucket 5 is moved to a predetermined discharging position by driving the boom cylinder 3a and the arm cylinder 4a, and the earth and sand in the bucket 5 is discharged. Then, the telescopic arm 4 is set again in the state shown in FIG. 2, and the same operation is repeated.
[0019]
Next, the mounting structure of the telescopic cylinder 45 will be described. 6 is an enlarged view of a portion VI in FIG. 2, FIG. 7 is a sectional view taken along line VII of FIG. 6, and FIG. 8 is a sectional view taken along line VIII-VIII in FIG. The upper end portion 45b of the tube of the telescopic cylinder 45 is disposed between the pair of left and right brackets 42a at the upper end portion of the second arm via the pad 451. A pair of left and right concave portions 452 are provided in the tube upper end portion 45b, and a pin 453 is inserted into the concave portion 452 through the bracket 42a and the pad 451. Thus, the upper end portion 45b of the tube is pin-connected to the second arm 42.
[0020]
At the upper end of the first arm 41, a plate 41d is fixed at right angles to the left and right inner side surfaces, and a pair of left and right plates 41e is fixed on the plate 41d. The rod upper end 45a of the telescopic cylinder 45 is disposed between the left and right plates 41e via the pad 454. An oil supply / discharge block 455 having an oil supply / discharge port 455a is attached to the rear surface of the rod upper end 45a by a bolt 456.
[0021]
At the upper end of the first arm 41, a pin 460 is inserted from the left through a mounting hole 41f on the left side of the arm. The pin 460 penetrates the plate 41e, the pad 454, and the rod upper end 45a, respectively. The left end flange 460a of the pin 460 is fixed to a screw seat 41g provided on the first arm 41 by a bolt 461. Thus, the rod upper end 45a is pin-connected to the first arm 41.
[0022]
As described above, when the rod upper end portion 45a and the tube upper end portion 45b of the telescopic cylinder 45 are pin-connected to the arms 41 and 42, respectively, the cylinder 45 is supported at two points in the longitudinal direction by the rotating end. Since the buckling load of the support by the rotating end is smaller than that of the support by the fixed end, the cylinder 45 is easily buckled when a compressive force acts during excavation work. In addition, since the telescopic cylinder 45 is long, the buckling load tends to be small.
[0023]
Therefore, in the present embodiment, the following configuration is adopted in order to increase the buckling load of the pin-connected telescopic cylinder 45, that is, to restrict the degree of freedom of rotation of the rod upper end portion 45a. When the degree of freedom of rotation of the rod upper end portion 45a is restricted, the degree of freedom of displacement of the telescopic cylinder 45 is reduced by that amount. However, a tensile force and a compressive force mainly act on the cylinder 45 of the telescopic arm 4 so that the bending direction is reduced. Since no force acts, priority is given to preventing buckling by restricting the degree of freedom of rotation.
[0024]
As shown in FIGS. 6 to 8, a substantially rectangular buckling prevention plate 470 is fixed to the upper end surface of the rod upper end portion 45 a along the longitudinal direction of the cylinder 45 by welding or the like. Pressing plates 471 and 472 are arranged before and after the buckling prevention plate 470, and the buckling prevention plate 470 is sandwiched between the pressing plates 471 and 472. The front pressing plate 471 is provided divided in the left and right (width direction), and each pressing plate 471 is provided with a step portion 471a, and the buckling prevention plate 470 provides a gap in the step portion 471a in the left and right direction. Is arranged.
[0025]
A pair of left and right screw seats 41h is provided on the plate 41d, and a screw hole 475a is formed in the screw seat 41h. Bolts 475 are screwed into the screw holes 475a through the holding plates 471, 472 and a pair of left and right spacers 473, and the spacer 473 and the holding plates 471, 472 are fixed to the screw seat 41h. The depth t1 of the step portion 471a is substantially the same as or slightly thinner than the thickness t2 of the buckling prevention plate 470.
[0026]
In this case, the rod upper end portion 45a positioned by the pin 460 such that a bending load does not act on the buckling prevention plate 470, that is, the buckling prevention plate 470 is positioned within the upper surface of the longitudinal extension line of the telescopic cylinder 45. The thickness of the spacer 473 is adjusted according to the mounting position. Thus, the displacement of the buckling prevention plate 471 in the front-rear direction, that is, the rotation, is restrained by the pressing plates 471 and 472 without applying an excessive load to the mounting portion (welded portion) of the buckling prevention plate 470. As a result, the buckling load of the telescopic cylinder 45 is increased as in the case where the rod upper end 45a is supported at the fixed end, and the cylinder 45 is less likely to buckle.
[0027]
In the present embodiment, since the buckling prevention plate 470 is not directly screwed to the arm 41, there is no need to provide a screw hole in the buckling prevention plate 470, and the processing is easy. This will be described in more detail. FIG. 9A shows a mounting structure of the buckling prevention plate 470 according to the present embodiment, and FIG. 9B shows a mounting structure when the buckling prevention plate 470 is directly screwed to the arm 41.
[0028]
When the buckling prevention plate 470 is fixed by bolts 475 that penetrate the buckling prevention plate 470 as shown in FIG. 9B, the height of the cylinder rod upper end 45a in the height direction (front-back direction) is adjusted to the dimension a. It is necessary to determine the dimension b of the buckling prevention plate 470 in the height direction. Further, it is necessary to form a screw hole in the buckling prevention plate 470 in accordance with the dimension c from the pin mounting hole 41f of the arm 41 to the screw hole 475a of the screw seat 41h. That is, in order to attach the buckling prevention plate 470 without applying a bending load to the buckling prevention plate 470, dimensional control in the height direction and the length direction is required. Therefore, the processing accuracy of the peripheral parts is required, and the cost is increased. When the buckling prevention plate 470 is directly fixed by the bolts 475 as shown in the figure, a local load acts on the bolt seat surface of the buckling prevention plate 470, and the buckling prevention plate 470 may be deformed. Further, the tensile force and the compressive force from the telescopic cylinder 45 act on the bolt 475, and the bolt 475 may be damaged by a shear load.
[0029]
On the other hand, as shown in FIG. 9A, in the present embodiment, the buckling prevention plate 470 is sandwiched and fixed between the pressing plates 471 and 472, so that the position of the buckling prevention plate 470 in the longitudinal direction is not restricted. . Therefore, it is only necessary to manage the dimension in the height direction (a, b), and this dimension management can be easily performed by adjusting the spacer 473. Since the buckling prevention plate 470 is in surface contact with the holding plates 471 and 472, no local load acts on the buckling prevention plate 470. Furthermore, since the buckling prevention plate 470 is movable in the longitudinal direction, no shearing force acts on the bolt 475.
[0030]
According to the hydraulic cylinder mounting structure of the above embodiment, the following operation and effect can be obtained.
(1) The buckling prevention plate 470 is protruded in the longitudinal direction at the rod upper end portion 45a, and the rotation of the buckling prevention plate 470 about the pin 460 as a fulcrum is restrained by the holding plates 471 and 472. Is supported in the same manner as the fixed end, and the buckling load increases. Thus, the buckling of the long cylinder 45 can be easily prevented without significantly changing the cylinder shape, that is, only by providing the buckling prevention plate 470 on the existing hydraulic cylinder 45.
(2) Since the buckling prevention plate 470 is sandwiched and fixed between the holding plates 471 and 472, there is no need to increase the dimensional accuracy in the longitudinal direction of the buckling prevention plate mounting portion. Costs can be reduced.
(3) Since the pressing plate 471 and the spacer 473 between the buckling prevention plate 470 and the screw seat 41h are provided separately on the left and right, the distance from the surface of the screw seat 41h to the buckling prevention plate 470 differs on the left and right. However, by inserting the spacers 473 having different thicknesses on the left and right, the buckling prevention plate 470 can be easily and easily fixed.
(4) Since the buckling prevention plate 470 is sandwiched between the holding plates 471 and 472, it is possible to prevent a local load from acting on the buckling prevention plate 470.
(5) Since the buckling prevention plate 470 can move in the longitudinal direction, it is possible to prevent a shear load from acting on the bolt 475.
(6) Since the holding plate 471 is provided with the step portion 471a and the buckling prevention plate 470 is disposed on the step portion 471a, the buckling prevention plate 470 can be positioned and fixed in the left-right direction, and can be buckled. The attachment of the prevention plate 470 is easy.
[0031]
Although the buckling prevention plate 470 is welded to the upper end surface of the rod upper end portion 45a, it may be fixed by bolts or the like instead of welding. In the above description, the rod upper end 45a and the tube upper end 45b are pin-connected to the arms 41 and 42. However, the cylinder tube and the cylinder rod may be fixed to separate arms 41 and 42, and at least one of them may be pin-connected. For example, the connection may be made at a position other than the upper end. Further, the rotation of the cylinder 45 is prevented by the buckling prevention plate 470, but other than the buckling prevention plate 470 may be used as the rotation preventing means. Although the buckling prevention plate 470 is provided at the pin coupling portion on the rod side to be a fixed end, the pin coupling portion on the tube side may be similarly a fixed end. Further, both the rod side and the tube side may be fixed ends.
[0032]
As the restraining means, the displacement is restrained by sandwiching the buckling prevention plate 470 by the holding plates 471 and 472, but the displacement may be restrained by a method other than sandwiching. Although the bolts 475 are used as fixing members for the holding plates 471 and 472, the holding plates 471 and 472 may be fixed using other than bolts. Although the pressing plate 471 is divided into two in the width direction (left-right direction), it is not necessary to divide the pressing plate 471, and it may be divided into three or more.
[0033]
In the above embodiment, the first arm 41 and the second arm 42 are connected by the telescopic cylinder 45, but the invention is not limited to this. That is, the second arm 42 and the third arm 43 may be connected by the telescopic cylinder 45, and a buckling prevention plate 470 may be provided in the same manner. Each of the arms 41 to 43 has a substantially rectangular cross section, but may have another shape (for example, a pentagon, a hexagon, or a circle). Further, although the three-stage telescopic arm 4 is used, there may be more stages. That is, an intermediate arm 42 may be provided in a plurality of stages. Although the lifting sheave 46 and the hose sheave 47 are integrated, they may be separate bodies.
[0034]
Although the case where the excavation work is performed has been described above, work other than the excavation may be performed. Further, in the above embodiment, the hydraulic excavator is used as the base machine, but another working machine (for example, a wheel excavator or a crane) can be used as the base machine. That is, the present invention is not limited to the embodiments as long as the features and functions of the present invention can be realized.
[0035]
【The invention's effect】
As described in detail above, according to the present invention, since the rotation of the pin connection portion of the hydraulic cylinder for extending and retracting the pin-coupled arm is prevented, the buckling load of the hydraulic cylinder can be increased. Thus, buckling of the cylinder can be easily prevented without significantly changing the cylinder shape.
[Brief description of the drawings]
FIG. 1 is a side view showing a working machine having a multi-stage telescopic arm according to an embodiment of the present invention.
FIG. 2 is a side view showing an excavation operation by a working machine having a multi-stage telescopic arm according to the embodiment of the present invention.
FIG. 3 is a side sectional view showing the internal configuration of the multistage telescopic arm according to the embodiment of the present invention (a diagram showing a state in which the arm is retracted).
FIG. 4 is a side sectional view showing the internal configuration of the multistage telescopic arm according to the embodiment of the present invention (a diagram showing a state where the arm is extended).
FIG. 5 is a sectional view taken along line VV of FIG. 3;
FIG. 6 is an enlarged view of a portion VI in FIG. 2;
7 is a VII view of FIG. 6;
FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 6;
FIG. 9 illustrates an effect of this embodiment.
[Explanation of symbols]
2 Revolving unit 3 Boom 4 Multi-stage telescopic arm 41 First arm 42 Second arm 43 Third arm 45 Hydraulic cylinder 45a Rod upper end 45b Tube upper end 470 Buckling prevention plates 471, 472 Holding plate 475 Bolt

Claims (5)

A multi-stage telescopic arm having a multi-stage telescopic arm,
A hydraulic cylinder that couples a cylinder rod and a cylinder tube to arms of different stages, and at least one of the cylinders is rotatably pin-connected to extend and contract the arm,
A rotation cylinder mounting mechanism for a multi-stage telescopic arm, comprising: a rotation preventing means for preventing rotation of a pin connecting portion of the hydraulic cylinder. The hydraulic cylinder mounting structure according to claim 1,
A plate member protruding in a longitudinal direction from one end surface of the hydraulic cylinder in the vicinity of the pin coupling portion; and a restraining device for restraining displacement of the plate member in a rotation direction of the hydraulic cylinder. A hydraulic cylinder mounting structure for a multi-stage telescopic arm, comprising: The hydraulic cylinder mounting structure according to claim 2,
The multi-stage telescopic arm, wherein the restraining means has a pair of pressing plates that sandwich the plate member from both sides, and a fixing member that fixes the pressing plate to the arm while sandwiching the plate member. Hydraulic cylinder mounting structure. The hydraulic cylinder mounting structure according to claim 3,
The holding cylinder interposed between the arm and the plate member is divided and provided in the width direction, and a hydraulic cylinder mounting structure for a multi-stage telescopic arm is provided. Traveling body,
A revolving structure that revolves on the traveling structure,
A boom installed so as to move up and down on the revolving structure,
A multi-stage telescopic arm working machine comprising: a multi-stage telescopic arm having a hydraulic cylinder mounting structure according to any one of claims 1 to 4 rotatably provided at a tip of the boom.

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