JP2002021108A - Telescopic arm of construction machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize and lighten a cylinder mounting part and to simlify assembly of a cylindrical body. SOLUTION: Bracket insertion holes 26, 26 are provided on an upper plate 12c and a lower plate 12d of an arm body 12 constituting an arm, a bracket 27 for cylinder mounting is inserted into the inside of the arm body from here, and it is fastened in a center impelling state. In the meantime, a pin introduction hole 30 is provided on an arm body side plate 12b, a cylinder mounting pin 32 is inserted into pin insertion holes 28, 28 of a bracket 27 and a pin hole 20b of a rod head end part 20a through the pin insertion hole 30, and the rod head end part 20a is mounted on the arm body 12.

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 which is expanded and contracted 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.

[0003] In the deep hole excavator, as shown in Fig. 4, an upper revolving unit 2 is mounted on a crawler type lower traveling unit 1 so as to be rotatable around a vertical axis. Mounted and configured.

The excavator A comprises a boom 3 attached to the upper swing body 2 so as to be able to move up and down, and a telescopic arm (extendable and retractable) attached to the tip of the boom 3 so as to be rotatable up and down around a horizontal axis 4. Arm) 5, a clam cell type bucket 6 attached to the tip of the arm 5, and a boom cylinder 7 for raising and lowering the boom 3 between the upper rotating body 2 and the boom 3, a boom 3 and an arm 5, an arm rotating cylinder 8 for rotating the arm 5 and a bucket cylinder 9 for opening and closing the bucket 6 between the arm 5 and the bucket 6.
Are provided respectively.

[0005] The arm 5 is configured to be telescopically extendable and retractable by a plurality of stages of cylindrical arms. Here, a case of a three-stage system including first, second, and third arm bodies 10, 11, and 12 in order from the base end side is illustrated, and the case of the three-stage system will be described below.

In this excavator, (a) excavating with a bucket 6 with the boom 5 upright as shown by a two-dot chain line in FIG. 4, and (b) a boom 3 and an arm as shown by a solid line in FIG. When the arm 5 is raised, the operation of dumping the scooped soil into the bucket 6 is repeated while expanding and contracting the arm 5 as needed, thereby excavating a deep hole.

As shown in FIG. 5, the arm 5, as shown in FIG. 5, has a first, second, and third arm bodies 10, 11, and 12 which are successively slidably fitted with the base end side outward. The first and second telescopic cylinders 13,
14 is driven to expand and contract.

The first telescopic cylinder 13 is configured such that the rod-side end of the cylinder tube 15 is
6 are attached to the first arm body 10 by cylinder mounting pins 17 and 18, respectively, and the second arm body 12 is moved by the expansion and contraction operation of the cylinder 13.
Expands and contracts with respect to

The second telescopic cylinder 14 is configured such that the head-side end of a cylinder tube 19 is
0 is attached to the third arm body 12 by cylinder mounting pins 21 and 22, respectively, and the third arm body 12 is moved by the expansion and contraction operation of the cylinder 14.
Expands and contracts with respect to

Conventionally, in such an arm 5, the rod end portions of the telescopic cylinders 13 and 14 are connected to the arm body 10,
The structure shown in FIG.

FIG. 6 shows the second arm 12 with respect to the second arm 12.
2 illustrates an example of a mounting portion of a rod end portion 20a of the telescopic cylinder 14.

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

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

[0014]

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

The cylinder thrust is applied to the central portion (point of force) of the cylinder mounting pin 22 and transmitted from both sides of the cylinder mounting pin 22 to the third arm body 12 via both side bosses 24, 24 (action points). For this reason, the distance from the point of force to the point of action is increased, and the moment is also increased.

In this case, both side bosses 24, 24 are
In the conventional structure mounted in a cantilever state on the 2a, 12b, there is a concern about the load supporting strength, particularly when the width of the arm body 12 is large 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 weight and size of the cylinder mounting portion are increased, and the reinforcing material (not shown) is added. , Work man-hours increase.

Moreover, the arm body 12 for this deep hole excavator
In the case of, instead of assembling into a cylindrical shape by connecting plates like a box boom of a crane, a square pipe material is used, so the mounting (welding) work of the reinforcing rib must be performed from within the arm body Therefore, the assembly of the arm body 12 is troublesome.

Accordingly, the present invention provides a telescopic arm of a construction machine capable of reducing the size and weight of a cylinder mounting portion and simplifying the assembly of a cylinder.

[0020]

According to the first aspect of the present invention, a telescopic cylinder is formed by a plurality of cylindrical bodies so as to be telescopically extendable, and a telescopic cylinder as a telescopic drive source extends between two adjacent cylindrical bodies. And, in the telescopic arm of the construction machine, the mounting portion of which is connected by pins to both cylinders,
Bracket insertion holes in two opposite side walls of the cylindrical body,
Pin introduction holes are respectively provided in the side walls perpendicular to the both side walls, a bracket having a pin through hole is mounted in the cylinder over the upper and lower bracket insertion holes, and the cylinder mounting pin is connected to the pin from outside the cylinder. The mounting portion of the telescopic cylinder is attached to the bracket by being inserted across the pin through hole of the bracket and the pin hole of the mounting portion of the telescopic cylinder via the introduction hole.

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

(I) The cylinder mounting pin is formed in a stepped and headless shaft shape having a small diameter at the distal end and a large diameter at the proximal end.

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

(Iii) The small diameter portion of the cylinder mounting pin penetrates across 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 mounted on the inner periphery of the boss.

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

According to a third aspect of the present invention, in the configuration 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 configuration of the third aspect, a second retaining ring as a lid stopper for fixing the lid in the boss at a position outside the lid inside the boss. Is attached.

According to the above construction, the bracket is inserted into the cylindrical body, and both ends of the bracket are attached to two opposing side walls of the cylindrical body.
Since the telescopic cylinder is attached to this bracket, as shown in FIG. 6, compared with a boss type structure in which the rod tip 20a is attached to the bosses 23, 24 attached to the cylindrical side plate in a cantilever state, Since the bracket, which is the load supporting member, is attached to the cylinder in a double-supported state, the load supporting strength is significantly increased, and the plate thickness of the bracket can be reduced.

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

(C) There is no need to add an extra reinforcing material.

From these points, the cylinder mounting portion including the bracket can be reduced in size and weight.

Also, the work of attaching the reinforcing member is not required, and the bracket can be easily attached by simply inserting the bracket 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 among the adjacent cylinders. If the cylinder mounting pin protrudes outside the inner cylinder, this pad is projected. The part and the pad may interfere with each other.

In this respect, according to the configuration of the second aspect, the cylinder mounting pin can be prevented from falling off inside the cylinder by the stepped portion of the pin and the retaining ring, and the pin can be projected outside the cylinder as in the prior art. Further, since the split pins for retaining do not protrude to the outer peripheral side of the pins outside the cylindrical body, there is no possibility of interference with the pads provided on the inner surface of the outer cylindrical body.

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

In this respect, according to the configuration of claim 3, the lid is screwed into the boss, and the lid can prevent intrusion of earth and sand into the boss, so that there is no possibility that the retaining ring comes off.

Further, according to the configuration of claim 4, the lid is:
Since the position is fixed in the boss by the second retaining ring, there is no possibility that the lid itself comes off.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS 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, the rod end of the second telescopic cylinder 14 shown in FIG.
2 is taken as an example.

Rod end portion 2 of third arm body 12
In the part where the first bracket 0a is mounted, window-shaped bracket insertion holes 26, 26 are provided in the upper plate 12c and the lower plate 12d, and a bracket 27 for mounting a cylinder extends over the upper and lower bracket insertion holes 26, 26. It is attached to the center of the body 12.

The bracket 27 has pin through holes 28,
28, an upper plate 27c, a lower plate 27d, and upper and lower plates 27c and 27d.
d is the upper plate 1 of the arm body at the bracket insertion holes 26, 26.
2c, and is fixed to the lower plate 12d by welding.

In each figure, 29, 29 are pin through holes 28, 2
8 is a backing plate fixed to the bracket both side plates 27a and 27b outside the base plate 8.

On the other hand, one of the left and right side plates 12 of the arm body 12
b, a pin introduction hole 30 is provided, and a short cylindrical boss 31 is provided.
Are welded and fixed in a state of being fitted into the pin introduction holes 30 and protruding inside the arm body.

The bracket 27 is mounted in such a manner as to be positioned in the arm body length direction or the like such that the pin passage hole 28 coincides with the pin introduction hole 30.

The tip end of the cylinder mounting pin 32 has a small diameter,
The base end is formed in a stepped and headless shaft shape having a large diameter, and a 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 at rod tip 20a → Bracket 27
Of the large-diameter portion 3
The base end of 2b is held in the boss 31.

The rod end 20a is mounted on the bracket 27 by the cylinder mounting pin 32.

According to this configuration, since the bracket 27 as a load supporting member is mounted inside the arm body 12 in a vertically supported state, the rod 27 is supported by the cantilevered bosses 24, 24 as shown in FIG. The load supporting strength is remarkably increased as compared with the case where the distal end portion 20a is attached. For this reason, the thickness of the bracket 27 can be reduced, and there is no need 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 20a.

From these points, the rod mounting portion including the bracket 27 can be reduced in size and weight, and the arm body 12 can be correspondingly reduced in weight.

Further, the operation of attaching the reinforcing member is not required, and the bracket 27 is provided with the arm body upper plates 12c and 12d.
It can be easily mounted simply by inserting it into the bracket insertion holes 26, 26 and welding the upper and lower ends.
Assembling of the arm body 12 becomes easy.

Further, the cylinder mounting pin 32 is mounted so that the entire pin does not protrude from the arm body 12 to the outside. Therefore, there is no possibility that the pad (not shown) provided on the inner periphery of the adjacent arm body (the second arm body 11 shown in FIG. 5) and the cylinder mounting pin 32 interfere with each other.

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

As shown in FIG. 2, the first retaining ring 33 is mounted on the distal end side in the boss 31 so as to be close to the base end surface of the cylinder mounting pin 32. The position of the cylinder mounting pin 32 is fixed (retained) in the axial direction by the step portion 32c.

The cover 34 is screwed into the boss 31 in a state of closing the boss 31 at an intermediate portion. The cover 34 prevents the earth and sand from entering the first retaining ring 33. This eliminates the possibility that the retaining ring 33 is removed by the intruded earth and sand and the cylinder mounting pin 32 falls off.

Numeral 34a is a nut into which a tool for screwing the cover 34 into the boss 31 or removing it as necessary is inserted. Instead of the nut 34a, a polygonal concave portion for inserting a tool may be provided in the lid 34.

In the above embodiment, the mounting portion of the cylinder rod tip portion 20a to the third arm body 12 has been exemplified. However, the present invention is not limited to the first telescopic cylinder 1 shown in FIG.
The present invention can be applied to a portion for attaching the rod tip of No. 3 to the first arm body 10 and to a portion for attaching a cylinder tube if conditions are satisfied. Further, the present invention can be widely applied not only to the arm of a deep hole excavator but also to a telescopic arm of a construction machine such as a boom of a crane.

[0058]

As described above, according to the present invention, since the bracket is mounted in the cylinder in a double-supported state in which both ends are supported by two opposing side walls, 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 case of the conventional boss type structure.

For this reason, the thickness of the bracket can be reduced, the width of the bracket can be set to the minimum size corresponding to the width of the rod tip, and there is no need to add an extra reinforcing material. Also, the cylinder mounting portion including the bracket can be reduced in size and weight.

Accordingly, the cost of parts can be reduced, and the working capacity can be improved by reducing the weight of the cylindrical body (extendable arm).

Furthermore, the work of mounting the reinforcing ribs becomes unnecessary, and the bracket can be easily mounted by simply inserting the bracket into the bracket insertion hole of the cylindrical body and welding the upper and lower ends thereof, thereby simplifying the assembly of the cylindrical body. be able to.

According to the second aspect of the present invention, the cylinder mounting pin can be prevented from coming off within the width of the cylinder by the step portion of the pin and the retaining ring, and the pin projects outside the width of the cylinder as in the prior art. In addition, since the retaining pin does not protrude to the outer peripheral side of the pin outside the cylinder, the pin does not interfere with the pad provided on the inner surface of the outer cylinder.

Further, according to the third aspect of the present invention, the cover screwed into the boss can prevent the intrusion of earth and sand into the boss. Therefore, there is no possibility that the snap ring is detached by the intruded earth and the cylinder mounting pin falls off.

According to the fourth aspect of the present invention, since the lid can be fixed in the boss by the second retaining ring, there is no possibility that the lid itself comes off.

[Brief description of the drawings]

FIG. 1 is a 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 part.

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

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

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

[Explanation of symbols]

5 Arms (Telescopic Arms) 10, 11, 12 First, Second, and Third Arms
Each arm body (cylindrical body) 13, 14 First and second telescopic cylinders 20 Rod of second telescopic cylinder 20a Rod end 20b Pin hole at rod end 12c Upper plate of second arm (side of opposite side wall) 1) 12d Lower plate of arm body (the other of the opposite side walls) 26, 26 Bracket insertion hole 27 Bracket 28, 28 Pin through hole of bracket 32 Cylinder mounting pin 32a Small diameter portion of cylinder mounting pin 32b Large diameter portion of the same pin 32c Step portion of the same pin 31 Boss 33 First retaining ring 34 Lid 35 Second retaining ring

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Eiji Shinkotani 3-12-4 Gion, Asaminami-ku, Hiroshima City Kobelco Construction Machinery Co., Ltd.Hiroshima Head Office (72) Inventor Takayuki Okunishi Asaminami-ku, Hiroshima City Gion 3-12-4 Kobelco Construction Machinery Co., Ltd. Hiroshima Head Office F-term (reference) 3F205 AA20 BA10 CA07 CB17

Claims (4)

[Claims] The telescopic cylinder as a telescopic drive source extends between two adjacent cylinders, and its mounting portion is a double cylinder body. In the telescopic arm of a construction machine attached by pin connection to the above, a bracket insertion hole is provided on two opposing side walls of the cylindrical body, and a pin introduction hole is provided on a side wall perpendicular to the both side walls. A bracket having a bracket is mounted in the cylinder over the upper and lower bracket insertion holes, and a cylinder mounting pin is provided between the pin through hole of the bracket and the mounting portion of the telescopic cylinder through the pin introduction hole from outside the cylinder. A telescopic arm for a construction machine, wherein the telescopic arm is attached to the bracket by being inserted over a pin hole. 2. The telescopic arm of a construction machine according to claim 1, wherein the telescopic arm has the following configuration. (I) The cylinder mounting pin is formed in a stepped and headless shaft shape with a small diameter at the distal end and a large diameter at the proximal end. (Ii) A cylindrical boss is attached to the inner surface of the side wall of the cylinder provided with the pin introduction hole. (Iii) The small diameter portion of the cylinder mounting pin penetrates across 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 mounted on the inner periphery of the boss. (V) The cylinder mounting pin is fixed in the pin length direction by the step portion of the pin and the retaining ring. 3. The telescopic arm of 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 position of the lid inside the boss is mounted at a position outside the lid inside the boss inside the boss.
The telescopic arm of the described construction machine.