JPH07292706A - Multistage expansible arm of construction machine - Google Patents

Abstract

PURPOSE:To drill a deep hole over the full length of a multistage expansible arm by drawing an extension in respective arms, and moving the lower end in the vicinity of the lower end of a base end arm. CONSTITUTION:At drilling by means of a chamshell bucket 7, a base end arm 3 supported with the extreme end of a boom 2, an intermediate arm 4, an extreme end arm 5 are respectively extended downward. Meanwhile, at pulling up earth and sand drilled on the III level, the intermediate arm 4 and the extreme end arm 5 are slid upward in the base end arm 3 and elevated up to the positions 4a, 5a. An extension 6 is drawn in the intermediate arm 4 and the base end arm 3, and the lower end 6d is moved in the vicinity of the lower end part of the base end arm 3. In addition, by lifting the boom 2 to the position 2a, the lower end of the clamshell bucket 7 is on the I level, and earth and sand drilled in a deep hole can be discharged on the ground surface GL.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multistage telescopic arm for a construction machine.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 16, a multistage telescopic arm C of a construction machine has a working device, a base end arm 3,
Intermediate arm 4, tip arm 5, hydraulic clam bucket 7
And the like, and the arms 3 and 4 extend downward from the base end arm 3. (For example, the actual exploitation 58-632
59). The operation will be described with reference to FIG. 17. First, when extending the arm, the hydraulic cylinder 1
The sixteen piston rods are extended to bring the upper movable sheave 120 closer to the fixed sheave 121, while moving the lower movable sheave 119 away from the fixed sheave 118. Then, the wire rope 115 on the upper side is loosened, and the acting force causes the intermediate arm 4 to drop downward due to its own weight via the sheave 112, and the wire rope 114 is pulled. As a result, the intermediate arm 4 is pulled downward and projects from below the base end arm 3. At the same time, the tip arm 5 supported by the wire ropes 110 and 111 via the guide sheaves 108 and 109 of the intermediate arm 4 extends downward simultaneously with the extension of the intermediate arm 4. At this time, since the intermediate arm 4 is pulled downward by the wire rope 114 on the front end side, the hydraulic clam bucket 7 on the front end is pulled.
The force acting on the tip arm 5, the wire rope 111,
Sheave 109, intermediate arm 4, wire rope 114, guide sheave 113, fixed sheave 118, movable sheave 11
9, the hydraulic cylinder 116 and the base end arm 3 are received in this order. Next, when retracting the arm, the hydraulic cylinder 11
The movable sheave 120 on the upper side by contracting the piston rod 6
Is moved away from the fixed sheave 121, while the lower movable sheave 119 is brought closer to the fixed sheave 118. Then, the wire rope 115 on the upper side is pulled, the intermediate arm 4 is contracted upward accordingly, and the sheave 108 of the intermediate arm 4 pushes the wire rope 110 upward, so that the tip arm 5 is contracted.

[0003]

However, in the conventional multistage telescopic arm of the construction machine shown in FIG.
I have the following problem: (A) When a deep hole is to be excavated, the dimension A is restricted by the extension length of the multistage telescopic arm, and only the extension length can be excavated. (B) The ascending position B of the bucket is restricted by the contraction length of the multistage telescopic arm and the swing angle of the boom of the construction machine. Therefore, when trying to load excavated earth and sand on the bed of a dump truck from a bucket such as a hydraulic clam bucket, rocking and turning operations must be performed at the same time, which requires skill.

A first object of the present invention is to provide a multistage telescopic arm for a construction machine capable of excavating a deep hole which is longer than the extension length of the multistage telescopic arm. When the multi-stage telescopic arm is contracted, the climbing position of the clam bucket can be secured above the height of the dump truck bed, and the swinging angle of the boom of the construction machine is not operated. The excavated earth and sand from a bucket such as a clam bucket,
A second object is to provide a multi-stage telescopic arm of a construction machine that can be loaded.

[0005]

In order to achieve the above first object, in the present invention, in a multistage telescopic arm connected to a boom 2 of a construction machine 1, up to an upper end 3d of a base end arm 3, It is characterized in that a driving means for sliding the arm lower end 4d is provided.

In the second aspect of the invention, which is mainly based on the first aspect, the lower end 6d for mounting the clam bucket 7 of the extension 6 attached to the tip of the multistage telescopic arm is located near the lower end of the base end arm 3. It is characterized in that a driving means for moving to is provided.

A third aspect of the invention, which is mainly composed of the first and second aspects, is characterized in that the extension 6 is mounted on a movable carriage 8 which is slidably attached along an arm. There is.

[0008]

In the multi-stage telescopic arm connected to the boom 2 of the construction machine 1 of FIG. 1 configured as described above, the arm lower end 4d can slide up to the upper end 3d of the base end arm 3.

Further, the lower end 6d for mounting the clam bucket 7 of the extension 6 attached to the tip of the multistage telescopic arm connected to the boom 2 of the construction machine 1 is located near the lower end of the base end arm 3. You can move.

The extension 6 attached to the tip of the multi-stage telescopic arm connected to the boom 2 of the construction machine 1 is mounted on a movable carriage 8 slidably attached along the arm. .

Further, the movable carriage 8 is attached so as to interlock with the sliding of the arm.

[0012]

EXAMPLES Examples will be described with reference to the drawings.
In FIG. 1, an intermediate arm 4 and a tip arm 5 are traversed to the outside of both ends of the base end arm 3 in a base end arm 3 that supports a tip end of a boom 2 of a construction machine 1 and that constitutes a multistage telescopic arm. It is installed to slide on. An extension 6 is attached to the tip of the tip arm 5, and a clam bucket 7 is attached to the tip thereof. As a result, each boom extends downward when excavating with the clam bucket 7. On the other hand, when pulling up the earth and sand excavated at the III level, the intermediate arm 4 and the tip arm 5 cross the inside of the base end arm 3 and slide 4a and 5a in the upper row,
Extension 6 to intermediate arm 4a, proximal arm 3a
It becomes possible to draw it in the extension 6
The lower extension end 6d on which the clam bucket 7 of FIG. 1 is mounted moves to the vicinity of the lower end of the base end arm 3. Further, when the boom 2 is lifted to the 2a position, the lower end of the clam bucket 7 becomes I level, and the earth and sand excavated in the deep hole can be discharged to the I level ground. G. L is
It represents the ground surface.

Further, in FIG. 2, the interpolating arm of FIG. 1 is a system in which a multi-stage telescopic arm is overlaid, and the reference numerals are outer overlaid base end arm 63 and outer overlaid intermediate arm 6.
4, the outer stack type front end arm 65, and the same parts as those in FIG. 1 are designated by the same reference numerals. The structure is such that, on the outer side of the base end arm 63, which is supported at the tip of the boom 2 of the construction machine 1 and constitutes a multi-stage telescopic arm, to the outer side of both ends of the base end arm 63,
An intermediate arm 64 and a tip arm 65 are installed so as to cross and slide in both directions. The extension 6 is attached to the tip of the tip arm 65, and at the tip thereof,
The clam bucket 7 is attached. As a result, each boom extends downward when excavating with the clam bucket 7.
On the other hand, when pulling up the earth excavated at the III level,
The intermediate arm 64 and the tip arm 65 cross the outside of the base end arm 63 and slide upward 64a and 65a. Since the extension 6 is suspended at the tip of the tip arm 65, it becomes 6a, and the boom 2 is moved to 2a. When lifted to the position, the lower end of the clam bucket 7a becomes I level, and the earth and sand excavated in the deep hole is discharged to the I level ground. When the embodiment of FIG. 14 is applied to FIG.
5, a movable carriage 8 having a pair of movable sheaves 82 and 83 mounted on the outer guide rail 67 of the drive pulley 92 and the idle pulley 93 is provided, and the pin hole 8 of the bracket 81 of the movable carriage 8 is provided.
Since the extension 6 is attached to the 4th end, the tip arm 6
By sliding 5 up to 8a, it becomes the position of the extension 66a, and the sediment discharge level of the clam bucket 7a can be increased from I to IV.

Further, in FIG. 3, the extension 61 longer than the extension 6 is attached to the movable carriage 8 of the tip arm 65. The operation is the same as that described with reference to FIG. 2 and will be omitted.
When level discharge to the ground is sufficient, it is possible to drill to the V level, which is a hole deeper than the III level.

FIG. 4 is an explanatory view of the operation of the multi-stage telescopic arm used in FIG. 2, in which fixed sheaves 12 and 13 mounted near the upper and lower ends of the base end arm 3 are disposed, and the fixed sheave is provided. A wire rope 9 is hung on. One end of the wire rope 9 is fixed to the lower end 11 of the intermediate arm 4, and the other end is fixed to the upper end 10 of the intermediate arm 4. Further, fixed sheaves 14 and 15 mounted near the upper and lower ends of the intermediate arm 4 are disposed, and wire ropes 16 and 17 are hung on the fixed sheaves, respectively. One end of the wire rope 16 is fixed to the upper end 18 of the proximal end arm 3, and the other end is fixed to the upper end 19 of the distal end arm 5. One end of the wire rope 17 is connected to the lower end 2 of the base arm 3.
It is fixed to 0, and the other end is fixed to the lower end 21 of the tip arm 5. Since the wire rope 9 is configured as described above, the intermediate arm 4 is moved upward and downward as indicated by the arrow by the driving means shown in FIGS.
The lower end 4d of the intermediate arm slides up to d. Further, when the intermediate arm 4 slides, the wire ropes 16 and 17 fixed to the upper and lower ends 19 and 21 of the distal arm are also pulled up by the fixed sheaves 14 and 15, so that the distal arm moves upward in the proximal end arm 3 a 5a. Slide to the position of the two-dot chain line and the position of the solid line below 5.

There are various means for driving the wire rope 9 up and down the arrow, but a typical example will be described with reference to the drawings. (A) FIG. 5 shows a means for using the winch 22. A wire rope 9 is hung on fixed sheaves 12 and 13 mounted near the upper and lower ends of the base arm 3. The other end of the wire rope 9 is fixed to the lower end 11 of the intermediate arm 4, and the other end is fixed to the upper end 10 of the intermediate arm 4. When the wire rope 9 is wound around the drum of the winch 22 driven by the motor 22a provided on the base end arm 3 and rotated clockwise, the wire rope 9 is driven up and down in the direction of the arrow, and the intermediate arm 4 moves. When the arm 4 slides upward and rotates counterclockwise, the intermediate arm 4 slides downward. (B) FIG. 6 shows a means for using the hydraulic cylinder 30. The two wire ropes 23 and 24 are fixed to the upper end 27 and the lower end 28 of the base end arm 3, and are hung on the fixed sheaves 12 and 13 via the movable sheaves 25 and 26. Wire rope 2
The other end of 3 is fixed to the lower end 11 of the intermediate arm 4, and the other end is fixed to the upper end 10 of the intermediate arm 4. The movable sheaves 25 and 26 are connected by a bracket 29, and when the hydraulic cylinder 30 is contracted, the movable sheave 25 moves downward and pulls the wire rope 23 downward, so that the intermediate arm 4 slides upward. . When the hydraulic cylinder 30 is extended and the movable sheave 26 is moved upward, the wire rope 24 is pulled upward, so that the intermediate arm 4 slides downward. To shorten the cylinder stroke, more sheaves or more movable sheaves may be added. (C) FIG. 7 shows a means of using the chain 31. A chain 31 is hung on fixed sheaves 12 and 13 mounted near the upper and lower ends of the base end arm 3. The other end of the chain 31 is fixed to the lower end 11 of the intermediate arm 4,
The other end is fixed to the upper end 10 of the intermediate arm 4.
If the sprocket 32 driven by the motor 22a provided on the base end arm 3 is wound and rotated clockwise,
The wire rope 9 is driven in the upward direction of the arrow, the intermediate arm 4 slides downward, and when rotated in the counterclockwise direction, the intermediate arm 4 slides upward. The idler wheels 33, 34 are
It is inserted in order to secure a winding angle when the chain 31 is wound around the sprocket 32.

FIG. 8 shows another embodiment of wire hanging,
The drive system of the means using the chain 31 is built in the tip arm 5. In the figure, the same symbols as those in FIG. 4 are assigned the same symbols. A chain 31 is hung on fixed sheaves 14 and 15 mounted near the upper and lower ends of the tip arm 5. One end of the chain 31 is fixed to the lower end 11 of the intermediate arm 4, and the other end is fixed to the intermediate arm 4
It is fixed to the upper end 10 of the. Wire ropes 16 and 17 are respectively hung on fixed sheaves 12 and 13 mounted near the upper and lower ends of the intermediate arm 4. One end of the wire rope 16 is fixed to the upper end 18 of the proximal end arm 3, and the other end is fixed to the upper end 19 of the distal end arm 5. One end of the wire rope 17 is connected to the lower end 2 of the base arm 3.
It is fixed to 0, and the other end is fixed to the lower end 21 of the tip arm 5. Since it is configured as described above, the tip arm 5
Sprocket 32 driven by motor 22a provided above
If you wrap it and rotate it clockwise, the chain 31
Is driven downward in the arrow so that the tip arm 5 slides downward, and when it is rotated counterclockwise, the tip arm 5 slides upward. The idle wheels 33 and 34 are inserted to ensure a winding angle when the chain 31 is wound around the sprocket 32. When the tip arm 5 slides, the wire ropes 16 and 17 fixed to the upper and lower ends 18 and 20 of the base arm 3 are also fixed sheaves 12 and 13.
The intermediate arm slides in the base end arm 3 to the upper position and the lower position because it is pulled by the hand. Similarly, although not shown, the means using a winch and the means using a hydraulic cylinder shown in FIGS. 5 and 6 can be incorporated in the tip arm 5.

Further, FIG. 9 is a view in which the driving means for the outer-stack type multistage telescopic arm of FIG. 2 is installed in the hydraulic cylinder 30 of FIG.
3, 24 are fixed to the upper end 27 and the lower end 28 of the base end arm 63, and fixed sheaves 12, 1 are passed through movable sheaves 25, 26.
Can be multiplied by 3. Further, the wire rope 23 is fixed to the lower end 11 of the intermediate arm. One wire rope 24 is fixed to the upper end 10 of the intermediate arm. Movable sheave 25, 2
6 are connected by a bracket 29, and are vertically driven by a hydraulic cylinder 30. Connect the two wire ropes 16 and 17 that move the distal arm 65 to the upper end 18 of the proximal arm 63.
Then, it is fixed to the lower end 20, is hung on the fixed sheaves 14 and 15 on the intermediate arm and the lower end, and is fixed to the tip arm upper end 19 and the tip arm lower end 21. With the above configuration, when the hydraulic cylinder 30 is contracted, the movable sheave 25 moves downward, so that the wire rope 23 is pulled up and the intermediate arm 64 moves upward. When the intermediate arm 64 moves upward, the tip arm 65 also moves upward due to the wire rope 17. Similarly, when the hydraulic cylinder 30 is extended, the movable sheave 26 moves upward, so that the wire rope 24 is pulled up and the intermediate arm 64 moves downward. When the intermediate arm 64 moves downward, the tip arm 65 also moves downward due to the wire rope 16. Further, means for using the chain 31 instead of the drive means for using the hydraulic cylinder 30,
Means using a winch can be used as well.

Further, FIG. 10 shows the driving means for the outer stacking type multistage telescopic arm shown in FIG. 2 installed on the intermediate arm 64. Sprockets 52 and 53 are mounted on the intermediate arm 64, and at least one is driven by a motor 22a. The chain 50 is fixed to the upper end 18 of the proximal end arm 63, hung on the sprocket 53, and fixed to the upper end 19 of the distal end arm 65. Further, the chain 51 is connected to the lower end 20 of the base arm 63.
Then, the sprocket 52 is hooked on the sprocket 52 and fixed to the lower end 21 of the tip arm 65. When the sprocket 52 is driven clockwise, the intermediate arm 64 and the tip arm 65 move upward, and the outer stacking multistage telescopic arm contracts and extends upward. Similarly, when the sprocket 52 is driven counterclockwise, the intermediate arm 64 and the tip arm 65 move downward, and the outer stacking type multistage telescopic arm extends downward. Similarly, as a means of using the winch 22, the chains 50 and 51 of FIG.
0a and 51a, and one of the sprockets 52 and 53 may be a winch.

FIG. 11 shows the hydraulic cylinder 30 of FIG.
Is installed in the intermediate arm 64, and the two wire ropes 23 and 24 are fixed to the lower end 20 of the proximal arm 63 and the lower end 11 of the intermediate arm 64, and the movable sheaves 25 and 26 are fixed.
Then, it is hung on the fixed sheaves 12 and 13. Further, the wire rope 23 is hung on the fixed sheave 14 at the upper end of the intermediate arm and fixed to the lower end 21 of the tip arm. One wire rope 24 is fixed to the upper end 10 of the intermediate arm. Further, the wire rope 54 shown by the broken line is attached to the base end arm 63.
Fixed to the upper end 18 of
It is fixed to the upper end 19 of the tip arm. With the above-described structure, when the hydraulic cylinder 30 is contracted, the movable sheave 2
As 5 moves downward, the wire rope 24 is pulled up and the intermediate arm 64 moves downward. Intermediate arm 6
4 moves downward, the tip arm 65 also moves the wire rope 5
Moves downwards by 4. Similarly, when the hydraulic cylinder 30 is extended, the movable sheave 26 moves upward, so that the wire rope 23 is pulled up and the tip arm 65 moves upward. When the tip arm 65 moves upward, the intermediate arm 64 also moves upward due to the wire rope 54. Similarly,
Chain 31 instead of means using hydraulic cylinder 30
It is also possible to use a means using a winch or a winch.

Further, FIG. 12 shows a driving means using a pin gear system, and the driving means is installed on the intermediate arm 64. Pin gears 74 and 75 are attached to the base end arm 63 and the tip end arm 65, and mesh with the sprocket 71 as shown in FIG. Sprockets 71 and 72 are mounted on the intermediate arm 64, and at least one of them is driven by a motor 22a. Sprocket 71,
A chain 73 is hung so as to rotate in synchronization with 72. When the sprocket 71 is driven clockwise, the intermediate arm 64 and the tip arm 65 move upward, and the outer stacking type multistage telescopic arm contracts. Similarly, when the sprocket 71 is driven counterclockwise, the intermediate arm 64,
The tip arm 65 moves downward, and the outer stacking type multistage telescopic arm extends.

Further, FIG. 14 shows an outer stacking type multi-stage telescopic arm to which a movable carriage 8 slidably attached along a tip arm 65 is attached. The movable carriage 8 has a movable sheave 8
2 and 83 are attached. A drive pulley 92 and a floating pulley 93 are attached to the upper and lower ends of the tip arm 65.
The wire rope 16 is fixed to the upper end 19 of the tip arm 65, hung on the movable sheave 83, and fixed to the lower end 11 of the intermediate arm 64 via the drive pulley 92. One wire rope 17 is fixed to the lower end 21 of the tip arm 65, is hung on the movable sheave 82, and is attached to the intermediate arm 64 via the idle pulley 93.
Fixed to the upper end 10 of the. The drive pulley 92 is connected to the motor 22.
Drive with a. Further, the drive pulley and the floating pulley may be interchanged vertically. The drive pulley 9 is constructed as described above.
When 2 rotates clockwise and the tip arm 65 slides upward from the lowest point to the highest point which is the position of 65a, the moving carriage 8 interlocks on the tip arm 65 to the position of 8a. To slide. This corresponds to the distance from the upper end to the lower end of the tip arm 65.

Further, FIG. 15 is a perspective view showing a state of the movable carriage 8 attached to the tip arm 65. The movable carriage 8 is fitted and slid into the rail 67 of the tip arm 65 by the bracket 81. Further, movable sheaves 82 and 83 are mounted in the bracket 81, and the wire rope 1
6 and 17 are hung. The pin holes 84 are for attaching the extensions 6 and 61.

Further, it is clear that the following constitution means is included in the method of driving the multistage telescopic arm of this embodiment. (A) A means for driving the wire rope of the multi-stage telescopic arm up and down with a winch. (B) A means for driving the wire rope of the multi-stage telescopic arm up and down by a hydraulic cylinder. (C) A means for driving the wire rope of the multi-stage telescopic arm up and down with a chain. (D) A means for vertically stacking the multi-stage telescopic arms, driving the intermediate arm up and down with a pin gear and a sprocket, and synchronizing the upper and lower sprockets with a chain.

[0025]

EFFECTS OF THE INVENTION Since the present invention is configured as described above, it provides a working device having a wide versatility as a multi-stage telescopic arm of a deep-hole excavator that has the effects described below. There is.

By being able to slide in both directions,
The stroke of the tip arm can be almost doubled as compared with the conventional one-side slide type.

Further, even if the extension is connected to the tip of the tip arm, the extension can be drawn into the middle arm and the base arm, and as a result, the excavated soil in the deep hole can be carried to the ground. At the same time, it is possible to drill the depth of the drilling hole to a level III deeper than the level II.

Further, since two movable sheaves for raising and lowering are provided on the movable carriage at the tip arm of the multistage telescopic arm of the construction machine, when the multistage telescopic arm is pulled up, the position of the clam bucket is set to the length of the tip arm. Since it is possible to move to a higher position IV level, excavated soil can be loaded directly on the bed of the dump truck. Further, since the extension is attached to the movable carriage, the movable carriage can be stably moved on the tip arm regardless of the fluctuation of the load from the extension.

Further, by providing the movable carriage of the movable sheave on the distal arm and mounting the extension on the movable carriage, the length of the proximal arm can be shortened and a compact working device can be provided. Furthermore, excavated soil is ground (GL)
When it is sufficient to carry it out, the long extension 61 which is longer than the tip arm can be attached. As a result, deep holes up to V level can be drilled.

[Brief description of drawings]

FIG. 1 is a side view showing a state in which a multistage telescopic arm of the present invention is mounted on a hydraulic excavator.

FIG. 2 is a side view of a combined state for comparative explanation of the clam bucket position when the movable carriage is attached to the tip arm of the outer stacking type multi-stage telescopic arm according to another embodiment of the present invention.

FIG. 3 is a multi-stage telescopic arm according to another embodiment of the present invention,
It is a side view of a state in which a movable carriage and a long extension are attached.

FIG. 4 is a partial vertical sectional view showing an embodiment of a multistage telescopic arm of the present invention.

FIG. 5 is a partial vertical cross-sectional view showing an embodiment in which the wire rope of the multistage telescopic arm of the present invention is driven up and down by a winch.

FIG. 6 is a partial vertical cross-sectional view showing an embodiment in which the wire rope of the multistage telescopic arm of the present invention is vertically driven by a hydraulic cylinder.

FIG. 7 is a partial vertical cross-sectional view showing an embodiment in which the wire rope of the multistage telescopic arm of the present invention is driven up and down by a chain.

FIG. 8 is a partial vertical cross-sectional view showing an embodiment in which a device for driving the wire rope of the multistage telescopic arm of the present invention up and down by a chain is incorporated in the tip arm.

FIG. 9 is a partial vertical cross-sectional view showing an embodiment in which the multistage telescopic arms of the present invention are superposed and the wire rope is driven up and down by a hydraulic cylinder.

FIG. 10 is a partial vertical cross-sectional view showing another embodiment in which the multistage telescopic arms of the present invention are superposed and the wire rope is driven up and down.

FIG. 11 is a partial vertical cross-sectional view showing another embodiment in which the multi-stage telescopic arms of the present invention are overlaid and the intermediate arm is driven by a hydraulic cylinder to move the wire rope up and down.

FIG. 12 is a partial vertical cross-sectional view showing another embodiment in which the multistage telescopic arms of the present invention are superposed on each other, and the intermediate arm is driven vertically by a pin gear and a sprocket, and the chains are used to synchronize the upper and lower sprockets. is there.

13 is a detailed view of a meshing portion between the pin gear and the sprocket shown in FIG.

FIG. 14 is a partial vertical cross-sectional view showing another embodiment in which the multistage telescopic arm of the present invention is superposed and the movable carriage is attached to the tip arm.

FIG. 15 is a perspective view in which a movable carriage is attached to the tip arm of the present invention.

FIG. 16 is a side view showing a state in which a multistage telescopic arm according to the related art is mounted on a hydraulic excavator.

FIG. 17 is a side view of a conventional multi-stage telescopic arm.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Construction machine, 2 ... Boom, 3 ... Base end arm, 3a ... Upper end of base end arm, 4d ... Lower end of arm, 6 ... Extension, 6d ... Lower end of extension, 7 ... Clam bucket, 8 ... moving dolly.

Claims (3)

[Claims] 1. A multi-stage telescopic arm of a construction machine, wherein a base end arm (3) of the multi-stage telescopic arm is attached to a boom (2) of the construction machine (1), and an upper end (3d) of the base end arm (3). Up to this, a multi-stage telescopic arm for construction machinery is provided with a drive means for sliding the lower end (4d) of the arm. 2. The multistage telescopic arm for a construction machine according to claim 1, wherein the extension (6) with a clam bucket (7) is attached to the tip of the multistage telescopic arm. A multi-stage telescopic arm for a construction machine, characterized in that a drive means for moving the base end arm (3) near the lower end is provided. 3. The extension according to claim 2.
(6) is a movable carriage that is slidably attached along the arm.
(8) A multi-stage telescopic arm for construction machinery, which is mounted on.