JP3330683B2 - Power shovel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power shovel with adjustable crawler belt spacing.

[0002]

2. Description of the Related Art Conventionally, in a power shovel in which an upper revolving body is rotatably provided on a self-propelled lower traveling body, a track frame a as shown in FIG. 1 is employed for the lower traveling body. That is, a track frame a provided at an interval on the left and right is connected and integrated by a center frame b, and a crawler belt (endlessly) is provided between idlers and sprockets provided before and after the track frame a. (Not shown)) to form a lower traveling body.

[0003]

In the above-mentioned conventional power shovel, the left and right track frames a constituting the lower traveling body are provided.
Are integrated by welding with the central frame b,
When working on narrow ground, the track spacing is too large,
There is a problem that it is not possible to enter narrow land and the place where work can be performed is limited. In addition, a small power shovel in which crawler belts are narrowed in advance for narrow terrain has poor stability in the lateral direction. The present invention has been made in order to improve such a problem, and an object of the present invention is to provide a power shovel in which a crawler belt interval can be adjusted according to a work place.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to achieve the above-mentioned object, and a power shovel having an upper revolving body rotatably provided on a self-propelled lower traveling body. The left and right track frames and the center frame that constitute the lower traveling body are provided with left and right gap adjustment mechanisms, and between the left and right track frames, a gap adjustment cylinder that adjusts the gap between the left and right track frames is provided. The mechanism is composed of four-bar parallel links, and connects the left and right parallel links to rotate the left and right front and rear links in conjunction.

[0005] With the above configuration, the interval between the crawler belts provided on the left and right track frames can be easily adjusted by the interval adjusting mechanism according to the work place, so that work on a narrow ground can be easily performed. Also, when working in a wide area, increasing the crawler track spacing improves lateral stability, so that work can be performed stably and narrower by increasing the crawler track spacing as much as possible even on narrow ground. Compared to a small power shovel that mainly works on the ground, it can work efficiently in a stable state. And left and right parallel links
By linking the left and right front and back links
While expanding and contracting almost equally,
It can be used evenly on the left and right
It can be.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described in detail with reference to the drawings shown in FIGS. FIG. 2 is an overall view of the power shovel. In this figure, 1 is a lower traveling body, 2 is an upper revolving body provided on the lower traveling body 1 so as to be freely rotatable.
A driver's seat 4 is provided at the rear.

As shown in FIG. 3, the lower traveling body 1 is provided with track frames 5 on the left and right sides so as to be parallel to each other.
A central frame 6 for mounting the center frame 6 is provided, and a space between both sides of the central frame 6 and each track frame 5 is connected via an interval adjusting mechanism 7 composed of four-node parallel links.

The spacing adjusting mechanism 7 has a front link 7a and a rear link 7b which are parallel to each other, and both ends of the front link 7a are provided at the front of the center frame 6 and the front sides of the left and right track frames 5. Both ends of the rear link 7b are pivotally connected to the rear portions of the center frame 6 and the left and right track frames 5 by pins 7d.

The end of the central frame 6 of one rear link 7b is connected to one end of an interlocking lever 7f via a pin 7d for supporting the same, and the end of the central frame 6 of the other rear link 7b is connected to the other end. The other end of each of the interlocking levers 7e and 7f is connected to an end of an interlocking lever 7g via a pin 7d that supports the linking lever 7e. It is designed to be rotated in conjunction with it.

On the other hand, between the rear link 7b and the pin 7d pivotally connecting the track frame 5, an interval adjusting cylinder 8 is suspended, and hydraulic pressure can be supplied to the interval adjusting cylinder 8 from a hydraulic source (not shown). It has become. The cylinder 8 may be provided between the link 7e and the center frame 6, and may be opened and closed by moving the link 7e or 7f.

Before and after the left and right track frames 5,
An idler 9 and a sprocket 10 are rotatably provided, and an endless crawler belt 11 driven to rotate by the sprocket 10 is wound between the idler 9 and the sprocket 10. Reference numeral 13 in the drawing denotes a blade provided at the front of the lower traveling body 1 so as to be vertically movable by a lift cylinder 14.

Next, the operation will be described. When working in a wide place, the interval adjusting cylinder 8 is extended. As a result, the front and rear links 7a and 7b of the gap adjusting mechanism 7 rotate in a direction perpendicular to the traveling direction, and the gap between the left and right track frames 5 increases. As a result, the interval between the crawler belts 11 increases, so that the work can be performed in a stable state. When working on a narrow ground, the interval adjusting cylinder 8 is contracted to reduce the interval between the left and right track frames 5. As a result, the interval between the crawler belts 11 is reduced, so that it is possible to easily enter narrow spaces and perform work.

As shown in FIG. 4, a distance adjusting cylinder 8 is connected via a switching valve 19 to a pipeline 18 branched from a hydraulic circuit 17 of a traveling motor 16 provided in the lower traveling body 1.
May be supplied with hydraulic pressure. In this case, the switching valve 19 is switched to the communication position 19a to make the rod side and the bottom side of the interval adjusting cylinder 8 communicate with each other.
When the undercarriage 1 is moved forward with the ground contact, the distance between the left and right track frames 5 increases due to the pressure receiving area difference of the distance adjusting cylinder 8 (the rod side is smaller by the rod cross-sectional integral), and decreases when moving backward.

Further, the switching valve 19 is switched to the shut-off position 19b.
, The rod side and the bottom side of the interval adjusting cylinder 8 are shut off, so that the left and right track frames 5 are fixed at the interval when the switching valve 19 is switched.

On the other hand, in the above-described embodiment, the interval adjusting mechanism 7 is constituted by four-bar links. FIG. 5 shows a conventional sliding type. That is, a slide cylinder 21 made of, for example, a square pipe having a diameter different from the facing surfaces of the left and right track frames 5.
a, 21b projecting from these slide cylinders 21a, 21b.
The tips of b are fitted to each other in a guide cylinder 21c provided before and after the central frame 6. An interval adjusting cylinder 8 is provided between the left and right track frames 5 so that the interval between the left and right track frames 5 can be adjusted by the interval adjusting cylinder 8. By adjusting the positions of the nuts 22a and 22b screwed to the stopper bolt 22, the enlargement position and the contraction position of the track frame 5 can be arbitrarily set.

Further, if the track frame whose distance is adjusted is fixed by the hydraulic pressure of the distance adjusting cylinder, it is not necessary to separately provide a stopper means for fixing the track frame.
The structure can be simplified.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a track frame of a conventional power shovel.

FIG. 2 is a perspective view of a power shovel according to one embodiment of the present invention.

FIG. 3 is a plan view showing an interval adjusting mechanism provided in the power shovel according to one embodiment of the present invention.

FIG. 4 is a circuit diagram showing a hydraulic circuit used for an interval adjusting mechanism provided in the power shovel according to one embodiment of the present invention.

FIG. 5 is an explanatory view showing an example of a conventional slide-type interval adjusting mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower traveling body 2 Upper revolving structure 5 Track frame 6 Central frame 7 Interval adjustment mechanism 7a, 7b Four-node parallel link 8 Interval adjustment cylinder

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-118388 (JP, A) JP-A-3-197275 (JP, A) JP-A-60-160282 (JP, U)

Claims (1)

(57) [Claims] 1. A power shovel having a revolving upper body (2) rotatably provided on a self-propelled lower traveling body (1), comprising: a left and right track frame (5) constituting the lower traveling body (1); Left and right spacing adjustment mechanism (7) between center frame (6)
And an interval adjusting cylinder (8) for adjusting the interval between the left and right track frames (5) is provided between the left and right track frames (5), and the interval adjusting mechanism (7) is a four-bar parallel link (7a). (7b) A power shovel, wherein the left and right parallel links are linked to rotate the left and right front and rear links in conjunction with each other.