JP3065560B2 - Pin connection device for construction machinery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pin connecting device for a construction machine, and more particularly to a pin connecting device for fixing an outer boom and an inner boom.

[0002]

2. Description of the Related Art FIG. 6 shows a general traveling crane 1 as an example of a construction machine.
A crane unit 3 is mounted on the carriage 2. Crane part 3
The outer boom 5 and the inner booms 6a, 6b, 6c... Are extended or retracted from the outer boom 5 to extend and retract the entire length of the boom 4. It is formed as follows. Here, in a state where the boom 4 is extended, the outer boom 5 and the inner boom 6a may be pin-connected in order to prevent breakage of the telescopic cylinder due to a hanging load.

As shown in FIG. 7, a pin 7 is provided so as to be able to protrude and retract from the side surface of the outer boom 5 toward the inner boom 6a, and when the boom 4 is extended by extending the inner boom 6a from the outer boom 5, A pin hole 8 is formed in the side surface of the inner boom 6a at a position where the tip of the protruding pin 7 is to be connected. Generally, pin 7
In order to facilitate the penetration of the pin, the diameter of the pin hole 8 is larger than the outer diameter of the pin 7 so that play is provided.

As shown in FIG. 8, when the pin 7 and the pin hole 8 are circular, if the pin hole 8 is much larger than the outer diameter of the pin 7, the pin 7 and the pin hole 8 may come into local contact. Then, stress concentration may occur at the point α and the pin 7 may be damaged. In order to avoid this stress concentration, if the diameter of the pin hole 8 is made as small as possible to eliminate backlash with the pin 7,
In order to align with the pin hole 8 when penetrating the pin 7, an adjustment mechanism for vertically moving the outer boom 5 and the inner boom 6a is required.

On the other hand, as shown in FIG. 9, similarly, when the pins 9 and the pin holes 10 are rectangular, if the backlash between the pins 9 and the pin holes 10 is large, local concentration occurs at the corners 10a of the pin holes 10. Happens. Also, as shown in FIG.
When the inner boom 6a inclines with respect to the outer boom 5 due to the bending of the pin 9, the pin 9 comes into contact with the pin hole 10 on one side, and stress concentration occurs at the β point.

Therefore, the pin and the boom are prevented from being broken by eliminating the stress concentration due to the local contact between the pin and the pin hole, and the vertical adjustment mechanism for aligning the pin hole when the pin is penetrated is eliminated. Therefore, a technical problem to be solved arises, and an object of the present invention is to solve this problem.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been proposed to achieve the above object, and comprises a telescopic boom comprising an outer boom and an inner boom, wherein a pin is provided from the outer boom to the inner boom. In a construction machine configured to penetrate the outer boom and the inner boom so as to be able to protrude and retract, the pin hole opened in the inner boom has a large-diameter circular hole and a small-diameter circular hole. An object of the present invention is to provide a pin connecting device for a construction machine in which the small holes are formed in overlapping slots and the diameter of the small holes is made to match the outer diameter of the pins.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. A general traveling crane will be described as an example of a construction machine. The configuration of the traveling crane 1 shown in FIG. 6 and the configuration of the pin coupling device shown in FIG. 7 have already been described in the section of the prior art, and thus redundant description will be omitted. The shape of the pin hole 8 in 7 is the shape of a pin hole 13 described later.

As shown in FIG. 1, when the inner boom 6a is extended from the outer boom 5 and the boom 4 is in the extended state, the tip of the pin 7 protruding from the side surface of the outer boom 5 toward the inner boom 6a. A pin hole 13 is formed at a position to be connected to the side surface of the inner boom 6a, and the pin 7 is inserted through the pin hole 13 to connect the outer boom 5 and the inner boom 6a.

As shown in FIG. 2, the pin hole 13 is formed as a long hole in which a large-diameter circular hole (diameter D ₁ ) 14 and a small-diameter circular hole (diameter D ₂ ) 15 are overlapped. Center 1 of circular hole 14
4a and the center 15a of the small diameter circular hole 15 are separated by a distance C. Further, the two circular holes 14 and 15 are connected by a tangent line 16, and a pin hole 13 is formed in a substantially oval shape. As shown in FIG. 3, the diameter D _{2 of the} pin 7 is equal to the diameter D ₂ of the small-diameter hole 15 and the large-diameter hole 1 is large.
4 for being smaller than the diameter D _1, backlash is provided for the circular hole 14 of larger diameter.

When the outer boom 5 and the inner boom 6a are pin-connected to each other with the boom 4 extended, first, as shown in FIGS. 1 and 3, the inner boom 6a is extended. The center 14 of the large-diameter circular hole 14
a near the position where the center 7a of the pin 7 coincides with the center 7a of the pin 7,
The pin 7 is protruded toward 3. In this case, the diameter D ₁ of the circular hole 14 of larger diameter is sufficiently larger than the diameter D ₂ of the pin 7, as in the prior art, without adjusting the outer boom 5 and the inner boom 6a vertically, easily pin 7 Through the pin hole 13.

The pin 7 is inserted into the large-diameter circular hole 14 of the pin hole 13.
If the inner boom 6a is slightly shrunk after passing through, the pin hole 13 moves with respect to the pin 7, and FIG.
As shown in the figure, the center 15a of the small-diameter circular hole 15 coincides with the center 7a of the pin 7. As described above, the small-diameter circular hole 15
Since the diameter D ₂ of the pin 7 is equal to the diameter D ₂ of the pin 7, the outer surface of the pin 7 uniformly contacts the small-diameter hole 15 over substantially half a circumference, and there is no contact of the pin 7 as in the related art. The occurrence of stress concentration can be prevented.

The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified ones.

[0014]

As described above, according to the present invention, a long hole obtained by overlapping a large-diameter circular hole and a small-diameter circular hole is used as a pin hole. Therefore, when the outer boom and the inner boom are pin-connected, By protruding the pin to the large-diameter circular hole portion of the pin hole, the pin can be penetrated very easily,
The vertical adjustment mechanism for the outer boom and the inner boom can be eliminated.

By slightly shrinking the inner boom, the pin matches the small-diameter circular hole of the pin hole,
Stress concentration due to local contact between the pin and the pin hole is eliminated, and damage to the pin and the boom can be prevented.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and is a partial cross-sectional view of a pin and a pin hole when a boom is in an extended state.

FIG. 2 shows an embodiment of the present invention and is an enlarged view of a pin hole.

FIG. 3 is an enlarged view of a pin and a pin hole in FIG. 1, showing the embodiment of the present invention.

FIG. 4 is a partial cross-sectional view of the pin and the pin hole in a state where the inner boom is slightly contracted from the state of FIG. 1 according to the embodiment of the present invention.

5 shows the embodiment of the present invention and is an enlarged view of a pin and a pin hole in FIG. 4;

FIG. 6 is a diagram showing a general traveling crane as an example of a construction machine.

FIG. 7 is a sectional view taken along line XX of FIG. 6;

FIG. 8 shows a conventional example, and is a partial cross-sectional view when a pin and a pin hole are circular.

FIG. 9 shows a conventional example, and is a partial cross-sectional view when a pin and a pin hole are rectangular.

FIG. 10 is a partial cross-sectional view of a pin and a pin hole in a state where the boom is bent from the state of FIG.

[Explanation of symbols]

 4 Boom 5 Outer Boom 6a, 6b, 6c Inner Boom 7 Pin 13 Pin Hole 14 Large Diameter Hole 15 Small Diameter Hole

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B66C 23/42 B66C 23/68 B66C 23/70

Claims (1)

(57) [Claims] A telescopic boom including an outer boom and an inner boom is provided, and a pin is penetrably penetrated from the outer boom to the inner boom so that the outer boom and the inner boom are pin-connected. In the construction machine described above, the pin hole opened in the inner boom is formed as a long hole in which a large-diameter hole and a small-diameter hole are overlapped, and the diameter of the small-diameter hole is set outside the pin. A pin coupling device for construction machinery, the diameter of which is matched to the diameter.