JPH08333766A - Telescopic arm structure for construction machine - Google Patents

Abstract

PURPOSE: To display sufficient workability in a tunnel by connecting a base bracket part of a lower arm to a boom tip part of a construction machine, and providing an upper arm in a longitudinally slidable state to the lower arm. CONSTITUTION: A lower arm 8 orthogonal to a longitudinal direction is formed into quadrangular box shape cross section, and an upper arm 11 is disposed in such a way as to cover an upper face side and lateral side face sides of the lower arm 8. A support bracket 12 is divided into an upper bracket body 19 and a lower bracket body 20. The upper bracket body 19 is rigidly welded to the outer side face part of the upper arm 11, and the lower bracket body 20 is rigidly fixed to the upper bracket body 19 by a bolt 21. Slide pads 22, 23 are then interposed between the upper and lower bracket bodies 19, 20 and a rail 10 corresponding to both bracket bodies 19, 20. The slide pads 22, 23 can thereby be replaced easily with new ones by removing the bolt 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telescopic arm mainly mounted on a work attachment such as a construction machine such as a hydraulic excavator or a work vehicle.

[0002]

2. Description of the Related Art FIG. 5 is a side view of a hydraulic excavator described in Japanese Utility Model Publication No. 63-100552. Figure 6
FIG. 6 is a sectional view taken along line I-I of FIG. 5. In the slide arm shown in FIGS. 5 and 6, the upper arm 2 is slid with respect to the lower arm 1, and the inner surface of the U-shaped portion of the bracket 4 that supports the rails 3 fixed to the left and right side surfaces of the upper arm 2 is provided. , Slide pads 5, 6, 7 divided into upper, lower and side portions are replaceably attached. Although not shown in the drawings, various telescopic arms having a tubular shape or a tubular shape with a notched upper portion are taken into consideration as described in, for example, Japanese Patent Laid-Open No. 5-339958.

[0003]

In the slide arm according to one embodiment of the prior art shown in FIGS. 5 and 6, since the lower arm and the upper arm are both formed in a box having a rectangular sectional shape, the height of the slide arm is increased. The thickness dimension H in the depth direction (shown in FIG. 6) becomes long, which may make it difficult to work at a work site such as in a tunnel, or may cause trouble when moving or transporting the machine body. . Further, since the rail supporting bracket is detachably attached to the upper surface of the lower arm so that the slide pad can be replaced, the mounting portion of the bracket is apt to be loosened due to the weight and impact of the upper arm, which is unsatisfactory. In addition, in a conventional tube type telescopic arm (not shown), the slide pads have to be attached to the four surfaces of the tubular body, and the attachment structure is complicated, so the assembly (productivity) is not good. In addition, the grease that has been applied to the upper arm (inner arm) of the above-mentioned tubular expandable arm
Since it sticks to the flat part of the side surface and the bottom surface of the stick that sticks out and earth and sand adhere to it, it is unsatisfactory in terms of maintainability and cleanliness. The present invention aims to solve the above problems.

[0004]

According to the present invention, a base bracket portion of a lower arm is connected to a boom tip portion of a construction machine, and an upper arm is provided slidably in the longitudinal direction with respect to the lower arm. In a telescopic arm that can be slid by a telescopic cylinder provided between the arms, the lower arm cross-sectional shape in the direction orthogonal to the longitudinal direction is formed into a rectangular box shape and covers the upper surface and left and right side surfaces of the lower arm. As described above, the cross-sectional shape of the upper arm in the same direction as that described above was formed into a substantially inverted U shape, and the upper arm was arranged outside the lower arm. Then, rails for slidingly guiding the upper arm with respect to the lower arm are provided so as to project on both left and right sides of the lower surface of the lower arm. A support bracket for supporting the rail is fixedly provided on the left and right outer side surfaces of the upper arm, and the rail is supported in proximity to the lower surface of the lower arm. In the above case, a plurality of support brackets are provided on the left and right outer surface portions on the rear side of the upper arm. Further, the support bracket is divided into an upper bracket body and a lower bracket body, the upper bracket body is fixed to the outer surface of the upper arm, and the lower bracket body is bolted to the upper bracket body. Then, in the above case, the lower bracket body is formed to have an L-shaped cross section in the left-right direction, and the upper surface portion, the side end surface portion, and the lower surface portion of the rail projecting to the side of the lower arm are respectively inserted through slide pads. The lower bracket body, the lower bracket body, and the lower bracket body are supported by the inner surface of the lower bracket and the inner surface of the lower bracket. Further, in the present invention, a wiper member for wiping off dirt is attached to the rear end edge of the upper arm on the upper surface side, and the lower end of the wiper member is brought into contact with the upper surface of the lower arm.

[0005]

In the present invention, the cross section of the lower arm in the direction orthogonal to the longitudinal direction is formed in a substantially U shape with the upper side open, and the inside of the lower arm has a rectangular cross section in the same direction as the above to form a box. Since the formed upper arm is arranged and the rails are projected on the left and right sides of the lower surface of the lower arm, the vertical thickness of the telescopic arm can be set to the minimum. Further, since the support brackets are fixedly provided on the left and right outer side surfaces of the upper arm, the rail can be supported close to the lower surface of the lower arm, and the portion of the lower arm above the rail is located inside the upper arm. Can be accommodated. The support bracket is divided into an upper bracket body and a lower bracket body, the upper bracket body is welded to the outer surface of the upper arm, and the lower bracket body is bolted to the upper bracket body. Even if the weight or impact of the upper arm is applied, the mounting portion of the upper bracket body to the upper arm does not loosen. The lower bracket body has an L-shaped cross section in the left-right direction, and the lower surface of the upper bracket body, the side inner surface of the lower bracket body, and the rail upper end and side end surface corresponding to the lower inner surface respectively. Since the slide pad is interposed between the lower pad and the lower surface, the slide pad can be easily replaced with a new one by removing the bolts that fasten the lower bracket to the upper bracket. Further, in the present invention, since the wiper member for wiping off the sand is attached to the rear end edge of the upper surface of the upper arm, when the telescopic arm expands and contracts, it cleans the earth falling on the rear upper surface of the lower arm. be able to.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a side view showing a contracted state of the telescopic arm of the present invention. Since the structure of the telescopic arm of the present invention is symmetrical, the parts on the left side are denoted by the reference numerals. In the figure, 8 is a lower arm of a telescopic arm, 9 is a base bracket portion of the lower arm 8 connected to the tip of a boom (not shown) of a hydraulic excavator, 10 is a rail fixed to the lower arm 8, and 11 is an upper part. An arm, 12 is a support bracket fixed to the side surface of the upper arm 11, 13 is a bucket cylinder mounting bracket that is erected on the upper surface of the upper arm 11, and 14 is a rear end edge of the upper arm 11 on the upper surface side. The attached wiper member, 15 is a telescopic cylinder provided between the lower arm 8 and the upper arm 11, 16 is a bucket cylinder, 17 is an idler link, and 18 is a push link. FIG. 2 is a sectional view taken along line AA of FIG. In the figure, 19 is an upper bracket body of the support bracket 12, 20 is a lower bracket body, 21 is a bolt, 22, 23 and 24 are slide pads, 25 and 26 are greasing ports for rail 10 lubrication respectively, and 27 is a base. It is a boss for attaching the boom tip portion of the bracket portion 9. FIG. 3 is a plan view seen from B of FIG. FIG. 4 is a side view showing an extended state (the extension stroke is the dimension S) of the telescopic arm shown in FIG.

Next, the structure of the telescopic arm of the present invention will be described with reference to FIGS. In the present invention, the cross-sectional shape of the lower arm 8 in the direction orthogonal to the longitudinal direction is formed in a rectangular box shape (portion indicated by reference numeral a) as shown in FIG. 2, and the upper surface and the left and right side surfaces of the lower arm 8 are formed. The upper arm 11 was formed to have a substantially U-shaped cross section in the same direction as the above so as to cover it, and the upper arm 11 was arranged outside the lower arm 8. Further, rails 10 for slidingly guiding the upper arm 11 with respect to the lower arm 8 are provided so as to project on both left and right sides of the lower surface of the lower arm 8. Support brackets 12 for supporting the rails 10 are fixedly provided on the left and right outer side surfaces of the upper arm 11, and the rails 10 are supported close to the lower surface of the lower arm 8. In the above case, two support brackets 12 are provided on each of the left and right outer surface portions on the rear side of the upper arm 11.

As shown in FIG. 2, the support bracket 12 has an upper bracket body 19 and a lower bracket body 2.
The upper bracket body 19 is divided into
The lower bracket body 20 was fastened to the upper bracket body 19 with the bolts 21 by fixing the lower bracket body 20 to the outer side surface by welding. In the above case, the lower bracket body 20 is formed to have an L-shaped cross-section in the left-right direction, and the upper surface portion, the side end surface portion, and the lower surface portion of the rail 10 projecting laterally from the lower arm 8 are respectively provided with slide pads. Via 22, 23, 24
Lower surface of upper bracket body 19, lower bracket body 20
The inner surface portion on the side and the inner surface portion on the lower side are supported. Further, in the present invention, the wiper member 14 for wiping off the sand is attached to the rear end edge of the upper arm 11 on the upper surface side, and the lower end portion of the wiper member 14 is attached to the upper surface portion of the lower arm 8 (reference numeral shown in FIG. Part).

Next, the operation of the telescopic arm structure of the present invention will be described. In the present invention, the cross-sectional shape of the lower arm 8 in the direction orthogonal to the longitudinal direction is formed in a rectangular box shape,
To cover the upper surface and the left and right side surfaces of the lower arm 8,
A cross-sectional shape of the upper arm 11 in the same direction as that described above is formed into a substantially inverted U shape, the upper arm 11 is arranged outside the lower arm 8, and rails 10 are provided on both left and right sides of the lower surface of the lower arm 8. Since the projection is provided, the vertical thickness dimension of the telescopic arm (referred to as dimension h shown in FIG. 2) can be set to the minimum. In addition, the above support bracket 1
Since 2 is fixedly provided on the left and right outer side surfaces of the upper arm 11, the rail 10 can be supported close to the lower surface of the lower arm 8 and the upper portion of the lower arm 8 above the rail 10 can be supported by the upper arm. It can fit inside 11.

The support bracket 12 is divided into an upper bracket body 19 and a lower bracket body 20, and the upper bracket body 19 is fixed to the outer side surface of the upper arm 11 by welding. Since the bolts 21 are fastened to the upper bracket body 19, even if the weight or impact of the upper arm 11 acts on the upper bracket body 19, the attachment portion of the upper bracket body 19 to the upper arm 11 does not loosen. The lower bracket body 20 has an L-shaped cross-section in the left-right direction, and the lower surface of the upper bracket body 19, the side surface of the lower bracket body 20, and the upper surface of the rail 10 corresponding to the lower surface of the lower bracket body 20, respectively. , The slide pad 22, between the side end surface portion and the lower surface portion,
Since 23 and 24 are provided, the slide pad 22, 23 and 24 can be easily replaced with a new one by removing the bolt 21. Further, in the present invention, since the wiper member 14 for wiping off the sand is attached to the rear end edge of the upper arm 11 on the upper surface side, the rear upper surface of the lower arm 8 (see FIG. 4) when the telescopic arm expands and contracts. It is possible to clean the earth and sand that have fallen to the part indicated by the symbol B).

[0011]

In the telescopic arm of the present invention, the lower arm has a substantially U-shaped cross-section with its upper side open, and the lower arm has a rectangular cross-section in the same direction as the above. Since the upper arm is arranged and the rails are projectingly provided on both left and right sides of the lower surface of the lower arm, the vertical thickness dimension of the telescopic arm can be set to the minimum. Therefore, sufficient workability can be exhibited at a work site having an obstacle or the like above, for example, a construction site in a tunnel, and the balance of the hydraulic excavator in the front-rear direction can be improved. In addition, the side-view shape of the telescopic arm can be made slim to improve its appearance. Further, since the support brackets are fixedly provided on the left and right outer side surfaces of the upper arm, the rail can be supported in the vicinity of the lower surface of the lower arm, and the portion of the lower arm above the rail is located inside the upper arm. Can be accommodated. The support bracket is divided into an upper bracket body and a lower bracket body, the upper bracket body is welded to the outer surface of the upper arm, and the lower bracket body is bolted to the upper bracket body. Even if the weight or impact of the upper arm is applied, the mounting portion of the upper bracket body to the upper arm does not loosen. The lower bracket body is formed in an L-shaped cross-section in the left-right direction, and the lower surface of the upper bracket body, the inner side surface of the lower bracket body, and the upper and side end surface portions of the rail corresponding to the inner surface of the lower bracket body, respectively. Since the slide pad is interposed between the lower pad and the lower surface, the slide pad can be easily replaced with a new one by removing the bolts that fasten the lower bracket to the upper bracket. Further, in the present invention, since the soil wiper member is attached to the rear end edge of the upper arm on the upper surface side, when the telescopic arm expands and contracts, the soil dropped on the rear upper surface of the lower arm is cleaned. be able to. Further, the telescopic arm device of the present invention has better assembling (productivity) than the conventional telescopic arm of the related art. That is, in the case of the tubular telescopic arm, the slide pads must be attached to the four faces of the tubular body and the attachment structure is complicated. However, in the present invention, the assembly can be performed easily and at low cost. Further, in the above-mentioned tubular telescopic arm, the grease that has been greased adheres to the flat surface of the side surface or the lower surface of the upper arm (inner arm) that extends, and earth and sand also adhere to it, but in the present invention, the adhesion of the grease is It is solved, and maintainability and cleanliness can be improved.

[Brief description of drawings]

FIG. 1 is a side view showing a reduced state of a telescopic arm of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a plan view seen from B of FIG.

FIG. 4 is a side view showing an extended state of the telescopic arm shown in FIG.

FIG. 5 is a side view of a hydraulic excavator equipped with a slide arm according to an embodiment of the prior art.

6 is a cross-sectional view taken along the line I-I of FIG.

[Explanation of symbols]

 1,8 Lower arm 2,11 Upper arm 3,10 Rails 5,6,7,22,23,24 Slide pad 9 Base bracket part 12 Support bracket 13 Bucket cylinder mounting bracket 14 Wiper member 15 Telescopic cylinder 19 Upper bracket body 20 Lower bracket body 21 Bolt

Claims (7)

[Claims] 1. A telescopic arm in which a base bracket portion of a lower arm is connected to a boom tip portion of a construction machine, and an upper arm is slidable in the longitudinal direction with respect to the lower arm, in a direction orthogonal to the longitudinal direction. The lower arm has a square box-shaped cross section, and the upper arm has a substantially U-shaped cross section in the same direction as the above so as to cover the upper surface and the left and right side surfaces of the lower arm. A telescopic arm structure for a construction machine, wherein an arm is arranged outside the lower arm. 2. The telescopic arm structure for a construction machine according to claim 1, wherein rails for slidingly guiding the upper arm with respect to the lower arm are provided on both left and right sides of a lower surface of the lower arm. A telescopic arm structure for construction machinery. 3. A telescopic arm structure for a construction machine according to claims 1 and 2, wherein support brackets for supporting the rail are fixedly provided on left and right outer side surfaces of the upper arm, and the rail is lowered. A telescopic arm structure for construction machines characterized in that it is supported close to the lower surface of the arm. 4. The telescopic arm structure for a construction machine according to claim 3, wherein a plurality of the support brackets are respectively arranged on the left and right outer side surfaces on the rear side of the upper arm. Telescopic arm structure. 5. The telescopic arm structure for a construction machine according to claim 3, wherein the support bracket is divided into an upper bracket body and a lower bracket body, and the upper bracket body is fixed to an outer surface portion of the upper arm. , The lower bracket body is bolted to the upper bracket body, which is a telescopic arm structure for a construction machine. 6. The telescopic arm structure for a construction machine according to claim 5, wherein the lower bracket body has an L-shaped cross-section in the left-right direction, and the rail is provided so as to project laterally from the lower arm. The upper surface portion, the side end surface portion, and the lower surface portion of the above are respectively supported by the lower surface portion of the upper bracket body, the inner side surface portion and the lower inner surface portion of the lower bracket body through slide pads. Telescopic arm structure for construction machinery. 7. A telescopic arm structure for a construction machine according to claim 1, wherein a wiper member for wiping off sand is attached to a rear end edge of the upper arm on the upper surface side.
A telescopic arm structure for a construction machine, wherein a lower end portion of the wiper member is brought into contact with an upper surface portion of a lower arm.