Wheel substitutes for land vehicles – With track support intermediate of end wheels – With roller support contacting lower track run
Reexamination Certificate
1999-01-28
2001-09-04
Morano, S. Joseph (Department: 3617)
Wheel substitutes for land vehicles
With track support intermediate of end wheels
With roller support contacting lower track run
C305S015000, C305S124000, C180S009210, C180S009500, C180S308000
Reexamination Certificate
active
06283562
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a pair of triangular crawler devices on opposite sides provided at either or both of the front and rear portions of a self-traveling vehicle, such as construction equipment, or the like.
BACKGROUND ART
A triangular crawler device in construction equipment will be explained with
FIG. 1. A
revolving superstructure
3
is mounted on a body
2
of construction equipment
1
. A working machine
4
having a bucket or the like, a driver's cab
5
, an engine compartment
6
, and the like are attached to the revolving superstructure
3
. The body
2
is provided with triangular crawler devices
7
which are travel devices. Specifically, a pair of rear triangular crawler devices
7
A on opposite sides, each having a driving element, are disposed at the rear portion of the vehicle
2
, and a pair of front triangular crawler devices
7
B on opposite sides, each having a driving element and a steering device, are disposed at the front portion of the vehicle
2
.
An example of such triangular crawler devices as above is described in Japanese Patent Laid-open No. 4-8682. Specifically, a track frame, including a front idler and a rear idler at the front and rear ends thereof respectively, is rotatably attached to a sprocket axle via a bearing. A crawler belt is wound around the outer peripheries of the sprocket and the front and rear idlers, and forms a triangular shape. Thus, when the vehicle travels on rough ground, the track frame rocks with the sprocket axle as a center following the lay of the ground, which reduces the rocking of the vehicle.
However, the above configuration has a disadvantage in that the front portion of the front triangular crawler device
7
B does not always turn upwardly but can turn downwardly, depending on conditions, to thereby cause it to stumble when the front idler collides with an obstacle in front while the vehicle travels.
SUMMARY OF THE INVENTION
The present inventors proposed a triangular crawler device disclosed in unpublished Japanese Application Patent No. 8-113219, to solve the aforesaid disadvantage. In
FIGS. 6 and 7
, which are concerned with the unpublished proposal, a sprocket
30
is attached to a body
2
of a vehicle, and the body
2
and the front portion of a track frame
31
are connected via pivot pins
33
A and
33
B and a front link
32
. The body
2
and the rear portion of the track frame
31
are connected via pivot pins
35
A and
35
B and a rear link
34
. The body
2
, the track frame
31
, the front link
32
, and the rear link
34
compose a four-node linkage. A distance L
4
between the lower connecting pins
33
B and
35
B is shorter than a distance L
3
between the upper connecting pins—
33
A and
35
A. A front idler ISA and a rear idler
15
B are attached to the front and rear ends of the track frame
31
respectively. Plural rollers
16
are attached to the lower face of the track frame
31
. A crawler belt
17
is wound around the outer peripheries of the sprocket
30
, the front idler
15
A, the rear idler
15
B, and the rollers
16
.
When force is applied to the front idler
15
A in the direction of an arrow F, that is, from the front as shown in
FIG. 8
, the track frame
31
rocks backwardly. At this time, however, the distance L
4
between the lower connecting pins
33
B and
35
B of the four-node link is shorter than the distance L
3
between the upper connecting pins
33
A and
35
A, as described above. Therefore, the front idler
15
A moves backwardly and upwardly, as shown with a broken line arrow d, and simultaneously the rear idler
15
B moves backwardly and downwardly, as shown with a broken line arrow e. Accordingly, a front triangular crawler device
7
B moves from a position shown with a two-dot chain line to a position shown with a full line in such a manner that the front portion thereof turns upwardly, and is postured to go over an obstacle
40
in front as shown in
FIG. 9
, whereby it is no longer stumbled.
However, in the configuration of the above unpublished proposal, the sprocket
30
is attached to the body
2
, and the track frame
31
is attached to the body
2
via the front link
32
and the rear link
34
so as to freely rock. Thus, when the track frame
31
rocks, the shape of a triangle xyz, formed by the center x of the sprocket
30
, the center y of the front idler
15
A, and the center z of the rear idler
15
B as shown in
FIG. 6
, changes. Consequently, the length of the outer peripheries of the sprocket
30
and the front and rear idlers
15
A and
15
B become shortened so that the crawler belt
17
loosens, which causes the situation that the crawler belt
17
easily comes off from the vehicle body
2
.
The present invention is made in view of the aforesaid disadvantage and an object thereof is to provide a triangular crawler device which is free from stumbling and whose crawler belt does not come off from the body of the vehicle while the vehicle travels.
According to the present invention, each one of a pair of triangular crawler devices, provided on opposite sides of at least one of the front and rear portions of a vehicle, is a triangular crawler device having a sprocket, front and rear idlers disposed below and in forward and backward directions from the sprocket, and a crawler belt wound around the sprocket and the front and rear idlers, including:
a track frame, having the front idler and the rear idler disposed at front and rear ends thereof,
the sprocket being rotatably mounted on the track frame,
links, connecting a body of the vehicle and the track frame together, and
the crawler belt being wound around the front idler, the rear idler, and the sprocket.
According to this configuration, the track frame and the sprocket integrally rock in the forward and backward directions relative to the vehicle body. At this time, the shape of a triangle, formed by the respective centers of the sprocket, the front idler, and the rear idler, does not change. Thus, the length of the outer peripheries of the sprocket and the front and rear idlers does not change. Consequently, there is no possibility of the crawler belt loosening and coming off of the vehicle body.
Moreover, it is preferable that the links form a four-node linkage with two links which are each attached to the body at a first end and attached to the track frame at the second end with pivot pins, and
the four-node linkage has a distance between pivot pins at the second ends of the two links which is shorter than a distance between the pivot pins at the first ends of the two links.
According to this configuration, when the track frame collides with an obstacle in front and moves backwardly, the front idler moves backwardly and upwardly and the rear idler moves backwardly and downwardly. Hence, the triangular crawler device turns upwardly at the front portion thereof and is postured to go over the obstacle, whereby it is no longer stumbled.
Furthermore, it is possible that a hydraulic motor is fixed to the track frame and the hydraulic motor rotationally drives the sprocket. Alternately, the sprocket and a driving source on the body can be connected with a universal joint and the sprocket can be rotationally driven via the universal joint.
According to this configuration, even when the track frame and the sprocket integrally rock in the forward and backward directions relative to the vehicle body, the sprocket can rotate, whereby the vehicle can travel.
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patent: 4114737 (1978-09-01), Fukui
patent: 4253708 (1981-03-01), Haslett
patent: 5273126 (1993-12-01), Reed et al.
patent: 5452949 (1995-09-01), Kelderman
patent: 5873640 (1999-02-01), Oertley
patent: 5899543 (1999-05-01), Lykken et al.
patent: 5954148 (1999-09-01), Okumura et al.
patent: 6007166 (1999-12-01), Tucker et al.
patent: 6164399 (2000-12-01), Bays
patent: 3-79421 (1991-04-01), None
patent: 4-8682 (1992-01-01), None
patent: 97 37885 (1997-10-01), None
Hiraki Hikosaburo
Hori Kazutoshi
Tsubota Haruhiro
Bellinger Jason R.
Komatsu Ltd.
Morano S. Joseph
Sidley Austin Brown & Wood
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