JP2575545Y2 - Construction machinery boom - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boom of a construction machine, and more particularly to a boom of a construction machine in which an inner boom is freely inserted into an outer boom so as to be able to expand and contract.

[0002]

2. Description of the Related Art A conventional construction machine boom will be described with reference to FIG. In the figure, reference numeral 1 denotes a boom.
The outer boom 2 is provided with slide shoes 3 at the front end portion of the inner surface of the upper plate 2a, and slide shoes 3a, 3 on the inner surfaces of both side plates 2b, 2b, respectively.
a, 3a, 3a, and the outer boom 2
The slide shoes 3b, 3b are also provided on the inner surface of the lower plate 2c, and the respective slide shoes 3, 3a, 3b are connected to the upper plate 4a, both side plates 4b, 4b and the lower plate 4c of the inner boom 4.
Are formed so as to come into contact with the vicinity of each corner. A gap δ is indispensable between the slide shoes 3, 3a, 3b provided on the outer boom 2 and the inner boom 4 because of the necessity in the assembly work of the boom 1. Therefore, except for the slide shoes 3b, 3b of the lower plate 2c of the outer boom 2, which are fixed from the beginning of the assembling process, the slide shoes 3, 3a of the upper plate 2a and the side plates 2b, 2b are respectively shims 5, 5. Are fixed after adjusting the gap with the inner boom 4 by inserting.

[0003]

[Problems to be solved by the invention]
When inserting the inner boom into the outer boom and assembling the boom, as described above, an appropriate gap is required between each slide shoe of the outer boom and the inner boom. Thus, the gap is uniformly adjusted by inserting a shim into the slide shoe.
However, since the number of the slide shoes to be adjusted is large, it takes a lot of man-hours to adjust the gap. Therefore, it is not possible to reduce the man-hour required for assembling the boom as much as possible and to improve workability. A technical problem to be solved arises, and the present invention aims to solve the problem.

[0004]

SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above-mentioned object, and is intended for a construction machine such as a crane truck equipped with a telescopic boom. At each corner, a cam shaft is pivotally mounted in the longitudinal direction of the boom, and a bracket is loosely fitted to the cam shaft, and slide shoes abutting on both upper corners of the inner boom are fixed, respectively. Provides a boom of a construction machine provided with a rotation stopping means.

[0005]

The clearance adjustment between the slide shoe of the outer boom and the inner boom, which is performed at the time of assembling the boom, is performed by rotating the cam shaft on which the bracket is loosely fitted. Thus, when the camshaft is rotated, the bracket loosely fitted on the camshaft moves obliquely at the corner of the inner boom. Thus, the slide shoe fixed to the bracket moves to change the distance between the slide shoe and the inner boom, and the gap between the two is properly adjusted. Thereafter, the rotation of the camshaft is stopped and fixed by stopping means provided on the camshaft and the outer boom.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIGS. FIG. 1 shows a crane truck as an example of a construction machine, and a telescopic boom 11 is attached to a body 10 so as to be able to move up and down. A sheave 12 is pivotally attached to the tip of the telescopic boom 11, a wire rope 13 is wound around, and a hook 14 is hung.

FIG. 2 is a sectional view taken along the line AA of FIG.
Shows a cross section taken along line BB of FIG. In the figure, inclined portions 17, 17 for attaching brackets 16, 16 are provided at both corners where the upper plate 15a and the side plates 15b, 15b of the outer boom 15 are joined. The brackets 16, 16
Is not limited to an inclined surface, but may be a curved surface. Thus, the inclined portions 17, 17 have an inclination angle of approximately 45 degrees with respect to the upper plate 15a and the side plates 15b, 15b of the outer boom 15.

Further, cam shafts 18, 18 are pivotally mounted on the inclined portions 17, 17 of the outer boom 15 in the longitudinal direction of the boom 11. Also, both ends 18 of the respective camshafts 18
a, 18a pivotally supported by the outer boom 15 and the eccentric portion 18b of the cam shaft 18 is provided with the bracket 1a.
6 is loosely fitted. Further, a slide shoe 19 is fixed to the inner surface of the bracket 16, and an arc-shaped concave portion 19a is formed on the outer surface of the slide shoe 19. On the other hand, both corners where the upper plate 20a of the inner boom 20 and the side plates 20b, 20b are joined are also arc-shaped, and are formed so as to fit into the concave portions 19a of the slide shoes 19 of the outer boom 15.

As shown in FIG. 3, the camshaft 18 through which the bracket 16 is inserted has the both ends 18a, 18a rotating about an axis X and the eccentric section rotating about an axis Y. 18b. Therefore, since the eccentric distance P is “radius R of both ends 18a” − “radius r of eccentric portion 18b”, the cam shaft 18 is rotated to be fixed to the bracket 16 and the bracket 16. The slide shoe 19 reciprocates within a range of twice the eccentric distance P.

As described above, by rotating the camshafts 18, 18 on which the brackets 16 are loosely attached,
The slide shoes 19, 1 of the outer boom 15
Adjustment of the gap between the inner boom 9 and the inner boom 20 can be performed very easily. Further, the camshafts 18, 18
Are provided in the vicinity of the end of the outer boom 15 so as to extend radially from the axis X.
The tip of a fixing bolt 22 screwed to one end face of the
There is provided a means for stopping the rotation of the cam shaft 18 so as to be inserted into any one of the above. After the clearance adjustment is completed, the stop bolt 22 is inserted into one of the many holes 21, 21... Provided near the end of the cam shaft 18.
Then, the rotation of the camshaft 18 is stopped by tightening the stop bolts 22, and the gap between the outer boom 15 and the inner boom 20 is maintained at a predetermined interval.

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 one.

[0012]

According to the present invention, as will be described in detail in the above embodiment, the bracket and the slide shoe move obliquely at both corners of the inner boom as the cam shaft rotates. Therefore, the gap between the slide shoe and the inner boom can be easily adjusted with high accuracy.

[0013] Thus, the present invention has various practical values, such as a reduction in man-hours and an improvement in quality in boom assembly.

[Brief description of the drawings]

FIG. 1 is a front view of a crane truck showing an embodiment of the present invention.

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

FIG. 3 is a sectional view taken along line BB of FIG. 2;

FIG. 4 is a cross-sectional view of a boom showing a conventional example.

[Explanation of symbols]

 11 Boom 15 Outer Boom 16 Bracket 17 Inclined Part 18 Camshaft 19 Slide Shoe 20 Inner Boom

Claims (1)

(57) [Scope of request for utility model registration] 1. A construction machine such as a crane truck equipped with a telescopic boom, wherein a cam shaft is pivotally mounted on both upper corners of a tip of an outer boom in a longitudinal direction of the boom, and a bracket is attached to the cam shaft. And a slide shoe that abuts on both upper corners of the inner boom, respectively, and the camshaft is provided with a rotation stopping means.