Motor vehicles – Special driving device – Portable track
Reexamination Certificate
2001-06-21
2003-08-05
Morris, Lesley D. (Department: 3611)
Motor vehicles
Special driving device
Portable track
C305S124000
Reexamination Certificate
active
06601664
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a crawler device provided in a crawler type of construction vehicle, a vehicle for traveling on an irregular ground, or the like.
BACKGROUND ART
FIG. 45
is a side view of a construction vehicle
2
having a crawler device in a triangular form. An upper revolving superstructure
4
is mounted on a vehicle body
3
of the vehicle
2
, and a working machine
5
, having a bucket or the like, is attached on the upper revolving superstructure
4
. The crawler devices
1
of triangular form, being traveling devices, are respectively provided at the front and the rear, and at the right and the left portions of the vehicle body
3
. Specifically, a pair of right and left crawler devices
1
A and
1
A, coupled to a steering device and a driving steering device and a driving device, are disposed at the front part of the vehicle body
3
; and a pair of right and left crawler devices
1
B and
1
B, coupled to the driving device, are disposed at the rear part of the vehicle body
3
. In order to make the explanation understandable, the crawler devices
1
A are taken as a pair of right and left crawler devices coupled to the steering device and the driving device, and the crawler devices
1
B are taken as a pair of right and left crawler devices coupled to the driving device. Further, the crawler devices
1
A and/or the crawler devices
1
B are collectively called the crawler device
1
.
The details of the crawler device
1
having a triangular form are disclosed in, for example, Japanese Laid-open Patent No. 4-8682. This will be explained with reference to FIG.
46
.
FIG. 46
is a sectional view of the rear end crawler device
1
B taken along the A—A line in FIG.
45
.
A sprocket
12
, rotationally driving a crawler belt
11
, is fixedly provided on the external perimeter of the outside end portion of a wheel hub
31
, which is on a side of the vehicle body
3
and is free to rotate. A bracket
13
is rotatably attached to the wheel hub
31
via a bearing
32
. A truck frame
15
, equipped with a roller
14
, is fixedly provided at the lower portion of the bracket
13
. The front end crawler device
1
A has the same configuration as above, and both of the crawler devices
1
A and
1
B are free to swing about the respective sprocket
12
. Each of the crawler devices
1
is supported on the vehicle body
3
by means of a suspension mechanism (not illustrated). Specifically, in the vehicle
2
, each crawler device
1
not only is in four-point contact with a road surface, but also can be evenly in contact with even an irregular ground surface with the aforesaid swing function of the crawler device
1
.
The truck frame
15
of the aforesaid crawler device
1
in a triangular form has a recoil spring
17
at almost the center portion between a front end idler
16
A and a rear end idler
16
B as shown in a schematic diagram in FIG.
47
. When the front end idler
16
A receives a large impactive force from the front, the recoil spring
17
contracts and the front end idler
16
A moves to the position shown by an alternate long and two short dashes line to thereby absorb the impactive force.
However, the aforesaid conventional crawler device
1
has the following disadvantages.
(1) The vehicle body
3
is supported by the truck frame
15
by means of the bearing
32
, which is placed nearer to the side of the vehicle body
3
than to the sprocket
12
. However, the bearing
32
is fitted onto the wheel hub
31
. Specifically, the bearing
32
is not provided on an axle beam (not illustrated) and the vehicle body
3
itself, and dose not support the vehicle body
3
. The wheel hub
31
is a rotary body for transmitting a rotational force to the sprocket
12
. Accordingly, unless the wheel hub
31
is constructed to have higher strength, there is a disadvantage in that the vehicle body
3
is difficult to be supported while smoothly transmitting the rotational force to the sprocket
12
. It is extremely disadvantageous for a working vehicle with heavy weight like the machines cited as an example. When the wheel hub
31
is highly strengthened, the wheel hub
31
is inevitably increased in size. Specifically, there is a disadvantage in that the vehicle height is difficult to be lowered.
(2) The wheel hub
31
is placed nearer to the vehicle body
3
than to the sprocket
12
. Therefore in a large-sized vehicle which contains a reduction gear such as a planetary gear train or the like, the configuration of the small space between the right and left sprockets
12
and
12
is complicated. Accordingly, there are disadvantages in that the vehicle height is difficult to be lowered, in that the distance between the sprockets
12
and
12
is difficult to be shortened (specifically, the vehicle width is difficult to be reduced), and in that the maintainability of the wheel hub
31
is worsened.
(3) The crawler device
1
is free to swing about the sprocket
12
. For this reason, as shown in
FIG. 48
, there is a disadvantage in that the front part of the front end crawler device
1
A faces downwardly (specifically, stumbles) when the vehicle
2
collides with an obstacle
6
in the front. The crawler device
1
is always free to swing; therefore, there is a disadvantage in that when an operation is carried out with the working machine
5
, the crawler device
1
swings, depending on the variations in the load on the working machine
5
, and on road conditions; and an operation to be carried out while standing firm cannot be carried out. Specifically, there is a disadvantage of unsatisfactory stability during operation.
SUMMARY OF THE INVENTION
The present invention is made to eliminate the aforesaid disadvantages of the prior art, and its object is to provide a crawler device for a crawler type vehicle with a simple structure, which lowers the vehicle height, decreases the vehicle width, has excellent maintainability, does not stumble even when colliding with an obstacle during traveling, and provides superior operation stability in a working vehicle.
A first configuration of a crawler device for a crawler type vehicle according to the present invention is, in a crawler type vehicle including, on the right and the left sides of either one of a front or a rear portion or both of the front and the rear portions of a vehicle body, crawler devices, each having a sprocket being a driving wheel, an idler being a driven wheel disposed on a truck frame, and a crawler belt passed around the sprocket and the idler, characterized by including a front end link, coupled to a forward part of the truck frame by means of a pin at a lower end portion thereof and to the vehicle body side by means of a pin at the upper end portion thereof, and a rear end link, coupled to a rearward part of the truck frame by means of a pin at the lower end portion thereof and to the vehicle body side at a position behind the front end link by means of a pin at the upper end portion thereof.
According to the first configuration, when an external force in a fore-and-aft direction is exerted on the truck frame, the truck frame can swing in the fore-and-aft directions, supported by the front link and the rear link. Accordingly, when the idler collides with an obstacle during traveling, the truck frame swings rearwardly and absorbs the impact. For this reason, the conventional recoil spring becomes unnecessary, thereby simplifying the configuration.
A second configuration is, in the aforesaid first configuration, characterized by the sprocket being disposed on either one of the front or the rear portion of the truck frame, and the idler being disposed on the other one of the front or the rear portion of the truck frame. According to the second configuration, in addition to the operational effects in the first configuration, a so-called low drive configuration is established. Specifically, the vehicle height can be lowered, and the position of the center of gravity is lowered, thereby improving the stability.
A third configuration is, in a crawler type vehicle including, on the right and left sides
Hiraki Hikosaburo
Hori Kazutoshi
Tsubota Haruhiro
Komatsu Ltd.
Morris Lesley D.
Sidley Austin Brown & Wood LLP
Yeagley Daniel
LandOfFree
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