JP3457267B2 - Construction machine telescopic arm - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telescopic arm of a construction machine that telescopes by a cylinder such as an arm of a deep hole excavator or a boom of a crane.

[0002]

2. Description of the Related Art A conventional technique will be described by taking an arm of a deep hole excavator as an example.

As shown in FIG. 4, in a deep hole excavator, an upper revolving structure 2 is mounted on a crawler type lower traveling structure 1 so as to be rotatable about a vertical axis, and an excavating device A is mounted on the upper revolving structure 2. Installed and configured.

The excavator A is equipped with a boom 3 which is mounted on the upper swing body 2 so as to be able to move up and down, and an extendable arm (extendable and retractable) which is attached to the tip of the boom 3 so as to be vertically rotatable about a horizontal axis 4. Arm) 5 and a clam-cell type bucket 6 attached to the tip of the arm 5, and a boom cylinder 7 for hoisting the boom 3 between the upper swing body 2 and the boom 3; 5, an arm rotation cylinder 8 that rotates the arm 5 between the arm 5 and the bucket cylinder 9, and a bucket cylinder 9 that opens and closes the bucket 6 between the arm 5 and the bucket 6.
Are provided respectively.

The arm 5 is constructed to be telescopically expandable and contractible by a plurality of arms as a cylindrical body. Here, a case of a three-stage type including the first, second, and third arm bodies 10, 11, and 12 is illustrated in order from the base end side, and the case of the three-stage type will be described below.

In this excavator, (a) the boom 5 is erected as shown by the chain double-dashed line in FIG. 4 and is excavated by the bucket 6, and (b) the boom 3 and the arm are shown as shown by the solid line in FIG. In the state where 5 is raised, the operation of dumping the scooped earth and sand into the bucket 6 is repeated while expanding and contracting the arm 5 as necessary, thereby excavating the deep hole.

As shown in FIG. 5, the arm 5 is constructed such that the first, second, and third arm bodies 10, 11, 12 are sequentially fitted slidably with the base end side facing outward. The first and second telescopic cylinders 13, which are configured to be telescopic,
It is driven to expand and contract by 14.

In the first telescopic cylinder 13, the rod-side end of the cylinder tube 15 is attached to the second arm body 11, and the rod 1
The tip end portions of 6 are attached to the first arm body 10 by cylinder attachment pins 17 and 18, respectively.
Expands and contracts.

In the second telescopic cylinder 14, the head side end of the cylinder tube 19 is attached to the second arm body 11, and the rod 2
The tip end of 0 is attached to the third arm body 12 by the cylinder attachment pins 21 and 22, respectively, and the expansion and contraction operation of the cylinder 14 causes the third arm body 12 to move.
Expands and contracts.

Conventionally, in such an arm 5, the rod tips of both telescopic cylinders 13 and 14 are connected to the arm body 10,
A structure shown in FIG. 6 is known as a structure to be attached to 12.

FIG. 6 shows the second arm for the third arm body 12.
The attachment portion of the rod tip portion 20a of the telescopic cylinder 14 is illustrated.

Left and right side plates 12a, 1 of the third arm body 12
The cylindrical boss 2 is provided with boss holes 23, 23 in 2b.
4, 24 are fitted in the boss holes 23, 23 and fixed by welding at the boss hole portions.

The cylinder mounting pin 22 is provided on both sides of the boss 2.
4, 24 and the pin hole 20b of the rod tip 20a, that is, the rod tip 20a is inserted in the third arm body 12 in the width direction.
It is attached to the arm body 12. In the drawing, 25 and 25 are retaining pins (for example, split pins) of the cylinder mounting pin 22.

[0014]

However, the conventional cylinder mounting structure has the following drawbacks.

The cylinder thrust is applied to the central portion (power point) of the cylinder mounting pin 22 and is transmitted to the third arm body 12 from both sides of the cylinder mounting pin 22 via both side bosses 24, 24 (points of action). Therefore, the distance from the force point to the point of action becomes long and the moment becomes large.

In this case, the both side bosses 24, 24 are the both side plates 1.
In the conventional structure in which the arm bodies 12 are mounted in a cantilevered manner on the 2a and 12b, there is concern about the load bearing strength, especially when the arm body 12 has a large width dimension and the moment is large.

For this reason, it is necessary to add a reinforcing material around the boss for reinforcement. As a result, the cylinder mounting portion becomes large in weight and size, and a reinforcing material (not shown) is added. , The work man-hour increases.

Moreover, the arm body 12 for this deep hole excavator
In the case of, instead of connecting the plate materials together like a box boom of a crane and assembling it into a tubular shape, since square pipe materials are used, the mounting (welding) work of the reinforcing ribs must be done from inside the arm body. Therefore, the assembly of the arm body 12 has been troublesome.

Therefore, the present invention provides a telescopic arm for a construction machine, in which the cylinder mounting portion can be made smaller and lighter and the assembly of the cylinder can be simplified.

[0020]

According to a first aspect of the present invention, a telescopic cylinder is constituted by a plurality of stages of cylinders, and a telescopic cylinder as a telescopic drive source extends between adjacent cylinders. And, in the telescopic arm of the construction machine in which the mounting portion is pin-connected to both cylinders and mounted,
Bracket insertion holes in the two side walls of the cylinder facing each other,
Pin introduction holes are respectively provided on the side walls perpendicular to the both side walls, a bracket having a pin through hole is mounted in the cylinder over the bracket insertion holes above and below, and a cylinder mounting pin is attached from the outside of the cylinder to the pin. The mounting portion of the telescopic cylinder is attached to the bracket by being inserted through the introduction hole to the pin through hole of the bracket and the pin hole of the mounting portion of the telescopic cylinder.

According to a second aspect of the present invention, in addition to the first aspect, the following configuration is provided.

(I) The cylinder mounting pin is formed in a stepless and headless shaft shape with a small diameter on the front end side and a large diameter on the base end side.

(Ii) A cylindrical boss is attached to the inner surface of the side wall of the cylinder having the pin introduction hole.

(Iii) The small diameter portion of the cylinder mounting pin penetrates the mounting portion of the telescopic cylinder and the pin through hole of the bracket, and the large diameter portion is held in the boss.

(Iv) A retaining ring is attached to the inner circumference of the boss.

(V) The cylinder mounting pin is positionally fixed in the pin length direction by the stepped portion of the pin and the retaining ring.

According to a third aspect of the present invention, in the structure of the second aspect, a lid for shielding the retaining ring from the outside is screwed into the boss.

According to a fourth aspect of the present invention, in the structure of the third aspect, a second retaining ring as a lid stopper for fixing the lid in the boss is provided at a position on the outer side of the tubular body inside the boss. Is attached.

According to the above construction, the bracket is inserted into the cylindrical body and both ends thereof are attached to the two side walls of the cylindrical body which face each other.
Since the telescopic cylinder is attached to this bracket, compared to the boss type structure in which the rod tip portion 20a is attached to the bosses 23 and 24 attached to the tubular side plate in a cantilever state as shown in FIG. Since the bracket, which is the load supporting member, is mounted in the cylinder in a double-supported state, the load supporting strength is remarkably increased, and the plate thickness of the bracket is small.

(B) The width dimension of the bracket can be set to the minimum dimension corresponding to the width of the rod tip portion.

(C) It becomes unnecessary to add an extra reinforcing material.

Due to these points, the cylinder mounting portion including the bracket can be made compact and lightweight.

Further, the work of attaching the reinforcing member is unnecessary, and the bracket can be easily attached by simply inserting it into the bracket insertion hole of the cylinder and welding both ends to the side wall of the cylinder. It can be simplified.

By the way, a pad for slidably supporting the inner cylinder is provided on the inner surface of the outer cylinder of the adjacent cylinders. When the cylinder mounting pin projects to the outside of the inner cylinder, this projection is provided. There is a risk of interference between parts and pads.

In this respect, according to the structure of claim 2, the cylinder mounting pin can be prevented from coming off in the cylinder body by the stepped portion of the pin and the retaining ring, and the pin can be projected out of the cylinder body as in the conventional case. Further, since the split pin for preventing slipping out does not project to the outer peripheral side of the pin outside the cylinder, there is no risk of interfering with the pad provided on the inner surface of the outer cylinder.

However, according to this structure, since the boss is open to the outside, there is a possibility that the retaining ring may come off due to the earth and sand entering the boss during the work.

In this respect, according to the third aspect of the invention, the lid is screwed into the boss, and the intrusion of earth and sand into the boss can be prevented by the lid, so that the retaining ring does not come off.

Further, according to the structure of claim 4, the lid is
Since the second retaining ring fixes the position inside the boss, there is no fear that the lid itself will come off.

[0039]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described with reference to FIGS.

In this embodiment, in accordance with the description of the prior art, in the arm 5 of the deep hole excavator of FIG. 4, the rod tip portion of the second telescopic cylinder 14 shown in FIG. 5 is connected to the third arm body 1.
2 is attached as an example.

The rod tip portion 2 of the third arm body 12
0a is attached to the upper plate 12c and the lower plate 12d, window-shaped bracket insertion holes 26, 26 are provided, and a bracket 27 for cylinder attachment extends across the upper and lower bracket insertion holes 26, 26. It is attached to the center of the body 12.

This bracket 27 has pin through holes 28,
The left and right side plates 27a and 27b, the upper plate 27c, and the lower plate 27d are provided with the upper plate 27c and the lower plate 27.
d is the bracket insertion hole 26, 26 and the arm body upper plate 1
2c, which is welded and fixed to the lower plate 12d.

In the drawings, 29 and 29 are pin through holes 28 and 2.
8 is a backing plate fixed to both side plates 27a and 27b of the bracket on the outer side of 8.

On the other hand, the left and right side plates 12 of the arm body 12
b has a pin introduction hole 30 and a short cylindrical boss 31.
Is fixedly welded and fixed in the pin introduction hole 30 so as to project inside the arm body.

The bracket 27 is attached by aligning it in the arm length direction and the like so that the pin through hole 28 thereof coincides with the pin introducing hole 30.

The cylinder mounting pin 32 has a small diameter on the tip side,
The base end side is formed in a stepless and headless shaft shape with a large diameter, and the small diameter portion 32a is provided with a pin introduction hole 30 from the outside of the arm body.
→ Inside the boss 31 → One pin through hole 28 of the bracket 27
-> Pin hole 20b of rod tip 20a-> Bracket 27
Of the large diameter portion 3
The base end portion of 2b is held in the boss 31.

With the cylinder mounting pin 32, the rod tip portion 20a is mounted on the bracket 27.

According to this structure, since the bracket 27, which is a load supporting member, is mounted in the arm body 12 in a vertically supported state, the rods are attached to the both-sided bosses 24, 24 supported in a cantilevered manner as shown in FIG. The load supporting strength is remarkably increased as compared with the case where the tip portion 20a is mounted. Therefore, the plate thickness of the bracket 27 can be thin, and it is not necessary to add an extra reinforcing material.

The width dimension of the bracket 27 can be set to the minimum dimension corresponding to the width of the rod tip portion 20a.

Due to these points, the rod mounting portion including the bracket 27 can be downsized and reduced in weight, and the arm body 12 can be reduced in weight accordingly.

Further, the work of attaching the reinforcing member is unnecessary, and the bracket 27 is provided on the upper plate 12c, 12d of the arm body.
By simply inserting it into the bracket insertion holes 26 of 26 and welding the upper and lower ends,
The assembly of the arm body 12 becomes easy.

Further, the cylinder mounting pin 32 is mounted in a state in which the entire pin does not project from the arm body 12 to the outside. Therefore, there is no possibility that the pads (not shown) provided on the inner circumference of the adjacent arm bodies (second arm body 11 shown in FIG. 5) and the cylinder mounting pin 32 interfere with each other.

On the other hand, in the boss 31, a first retaining ring 33, a lid 34, and a second retaining ring 35 are attached in this order from the tip side.

As shown in FIG. 2, the first retaining ring 33 is mounted on the tip end side of the boss 31 close to the base end face of the cylinder mounting pin 32, and the retaining ring 33 and the cylinder mounting pin 32 are attached. The cylinder mounting pin 32 is axially fixed (removed) by the step portion 32c.

The lid 34 is screwed into the boss 31 in a state where it is closed at the intermediate portion, and the lid 34 prevents earth and sand from entering the first retaining ring 33. This eliminates the possibility that the retaining ring 33 will be removed by the intruding sand and the cylinder mounting pin 32 will fall out.

Reference numeral 34a is a nut into which a tool for screwing the lid 34 into the boss 31 or removing it as necessary is inserted. Instead of the nut 34a, the lid 34 may be provided with a polygonal recess for inserting a tool.

By the way, in the above embodiment, the mounting portion of the cylinder rod tip portion 20a to the third arm body 12 is illustrated, but the present invention is the first telescopic cylinder 1 shown in FIG.
It can be applied to a portion where the rod tip end of 3 is attached to the first arm body 10 and also to a portion where the cylinder tube is attached if conditions are satisfied. Further, the invention can be widely applied not only to the arm of a deep hole excavator but also to the telescopic arm of a construction machine such as a boom of a crane.

[0058]

As described above, according to the present invention, the bracket is mounted in the cylinder in a double-supported state in which both ends are supported by the two side walls facing each other, and the telescopic cylinder is mounted on the bracket. The load supporting strength of the cylinder mounting portion can be remarkably increased as compared with the conventional boss type structure.

For this reason, the thickness of the bracket can be made thin, the width of the bracket can be set to the minimum size corresponding to the width of the rod tip portion, and it is not necessary to add an extra reinforcing material. The cylinder mounting part including the bracket can be made smaller and lighter.

Therefore, the cost of the parts can be reduced and the workability can be improved by reducing the weight of the tubular body (extendable arm).

Moreover, the work of attaching the reinforcing ribs is unnecessary, and the bracket can be easily attached simply by inserting it into the bracket insertion hole of the tubular body and welding the upper and lower ends thereof, thereby simplifying the assembly of the tubular body. be able to.

According to the second aspect of the invention, the cylinder mounting pin can be prevented from coming off within the width of the cylinder by the stepped portion of the pin and the retaining ring, and the pin protrudes outside the width of the cylinder as in the conventional case. In addition, since the split pin for preventing slipping out does not project to the outer peripheral side of the pin outside the cylinder, there is no risk of the pin interfering with the pad provided on the inner surface of the outer cylinder.

Further, according to the third aspect of the present invention, the lid body screwed into the boss can prevent dirt and sand from entering the boss. Therefore, there is no possibility that the retaining ring will come off due to the entered sand and the cylinder mounting pin will fall out.

According to the fourth aspect of the present invention, since the lid body can be fixed in position within the boss by the second retaining ring, there is no fear that the lid body itself will come off.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a cylinder mounting portion according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is an exploded perspective view of the same portion.

FIG. 4 is a schematic side view of a deep hole excavator that is an application example of the present invention.

FIG. 5 is a schematic cross-sectional view of an arm of the excavator.

FIG. 6 is a sectional view of a conventional cylinder mounting portion of the arm.

[Explanation of symbols]

5 Arms (expandable arms) 10, 11, 12 First, second and third arms
Each arm body (cylindrical body) 13, 14 First and second telescopic cylinder 20 Rod 20a of the second telescopic cylinder 20a of the same rod end portion 20b Pin hole 12c of the rod end portion Upper plate of the second arm body (opposite side walls) One side) 12d Lower plate of arm body (other side wall facing each other) 26, 26 Bracket insertion hole 27 Bracket 28, 28 Bracket pin through hole 32 Cylinder mounting pin 32a Cylinder mounting pin small diameter part 32b Large diameter part of the same pin 32c Step portion 31 of the pin 31 Boss 33 First retaining ring 34 Lid body 35 Second retaining ring

─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Eiji Shingoya, 3-12-4 Gion, Asanan-ku, Hiroshima City Kobelco Construction Machinery Co., Ltd. Hiroshima Head Office (72) Inventor Takayuki Okunishi Asanan-ku, Hiroshima City Gion 3-12-4 Kobelco Construction Machinery Co., Ltd. Hiroshima Head Office (56) Reference JP-A 51-141153 (JP, A) JP-A 2-101843 (JP, A) JP-A 9-184160 ( JP, A) Actual development Sho 62-183698 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) E02F 3/39 B66C 23/42 B66C 23/687

Claims (4)

(57) [Claims] 1. A telescope-like telescopic structure composed of a plurality of stages of cylinders, and a telescopic cylinder as a telescopic drive source straddles both adjacent cylinders, and its mounting portion is both cylinders. In a telescopic arm of a construction machine that is attached by being pin-connected to each other, bracket insertion holes are provided in the two side walls of the cylinder facing each other, and pin introduction holes are provided in the side walls perpendicular to these side walls. The bracket provided with is mounted inside the cylinder straddling the upper and lower bracket insertion holes, and the cylinder mounting pin is provided from the outside of the cylinder through the pin introduction hole to the pin insertion hole of the bracket and the mounting portion of the telescopic cylinder. An extendable arm for a construction machine, wherein the attaching portion of the extendable cylinder is attached to the bracket by being inserted across the pin hole. 2. The telescopic arm for a construction machine according to claim 1, wherein the telescopic arm has the following configuration. (I) The cylinder mounting pin is formed in a stepless and headless shaft shape with a small diameter on the front end side and a large diameter on the base end side. (Ii) A cylindrical boss is attached to the inner surface of the side wall of the cylinder having the pin introduction hole. (Iii) The small diameter portion of the cylinder mounting pin passes through the mounting portion of the telescopic cylinder and the pin through hole of the bracket, and the large diameter portion is held in the boss. (Iv) A retaining ring is attached to the inner circumference of the boss. (V) The cylinder mounting pin is positionally fixed in the pin length direction by the stepped portion of the pin and the retaining ring. 3. A telescopic arm for a construction machine according to claim 2, wherein a lid for shielding the retaining ring from the outside is screwed into the boss. 4. A second retaining ring as a lid stopper for fixing the lid in the boss is mounted at a position on the outer side of the cylindrical body in the boss than the lid.
Telescopic arm of the listed construction machine.