Wheel substitutes for land vehicles – With means to remove or exclude foreign matter
Reexamination Certificate
2002-05-31
2004-03-09
Stormer, Russell D. (Department: 3617)
Wheel substitutes for land vehicles
With means to remove or exclude foreign matter
C305S107000, C305S116000, C305S132000
Reexamination Certificate
active
06702406
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a travel gear of a crawler work vehicle.
2. Description of the Related Art
A conventional travel gear of a crawler work vehicle can travel, for example as shown in
FIG. 6
, generally by providing a pair of right and left track frames
2
and
2
in the lower part of the body in the longitudinal direction of the vehicle, rotating a crawler
6
rotatably wound around the track frames
2
via a sprocket
4
, and rolling a plurality of track wheels
11
rotatably attached to the lower part of the track frame
2
on the inner face (hereinbelow, called a wheel tread) of the crawler
6
.
FIG. 7
shows a first prior art of such a travel gear, and is a side view of a travel gear having a fixed track wheel disclosed in Japanese Patent Publication No. Sho-63-16313. An idler
3
is rotatably attached to one end in the longitudinal direction of the track frame
2
, and the sprocket
4
is rotatably attached to the other end. To brackets fixed to the lower part of the track frame
2
, a plurality of fixed track wheels
11
are rotatably attached at predetermined intervals. The crawler
6
is wound around the idler
3
, sprocket
4
, and track wheels
11
, and the track wheels
11
rolls on the tread of the crawler
6
. If a foreign matter such as a rock enters between the track wheel
11
and the crawler
6
, the track wheel
11
comes off from the crawler
6
or meanders. Consequently, to prevent a foreign matter from entering the space between the track wheel
11
and the crawler
6
, a fixed cover
51
covering the outer side face of the plurality of track wheels
11
is integrally attached so as to extend from the idler
3
to the sprocket
4
in the lower part of the track frame
2
.
On the other hand, a crawler travel device in which a crawler is prevented from coming off by preventing a track wheel from running on the tread of the crawler by making the track wheel follow a change in the vertical direction of the crawler due to rough or uneven terrain at the time of travel, and which realizes stable high-speed driving is also known.
FIG. 8
shows a second prior art of the crawler travel device and is a side view of, for example, a travel device having a swingable track wheel disclosed in Japanese Unexamined Patent Application No. Sho-53-53843.
In
FIG. 8
, at both ends in the longitudinal direction of the track frame
2
, idlers
3
and
3
are rotatably attached to one end on the outside of first arms
53
and
53
provided so as to swing vertically, an almost center part of each of second arms
55
and
55
is swingably attached to one end on the inside of each of the first arms
53
and
53
, and a pair of front and rear swingable track wheels
11
and
11
are rotatably attached to both front and rear ends of each of the second arms
55
and
55
which are swingable in the vertical direction. In the lower part of the track frame
2
between the front and rear idlers
3
and
3
, an almost center part of the second arm
55
is swingably attached to the tip of a third arm
56
provided so as to be vertically swingable, and the pair of front and rear swingable track wheels
11
and
11
are rotatably attached to both front and rear ends of the second arm
55
. Further, above the track frame
2
, the sprocket
4
is rotatably attached in the rear part of the body. A crawler
6
is wound around the idlers
3
and
3
, sprocket
4
, and plurality of swingable track wheels
11
. An elongated guide member
54
is attached to the lower end of each of the first arms
53
by a bolt. The guide members
54
are positioned on both sides of the crawler width direction so as to be in contact with the outer side faces of a link (not shown) of the crawler
6
. Further, an elongated member
57
is attached to the lower end of the third arm
56
by a bolt, positioned along both sides in the crawler width direction, and also positioned so as to be in contact with the link of the crawler
6
.
The elongated guide member
54
and elongated member
57
position in the transverse direction of the crawler
6
with respect to the track frame
2
and the track wheels
11
and
11
, thereby preventing the crawler from coming off.
In recent years, to prevent the crawler from coming off when a crawler work vehicle such as bulldozer or hydraulic excavator travels on an uneven ground and to assure stability of high-speed travel, a travel gear having a swingable (so-called bogie type) track wheel is often used. Therefore, in the travel gear having the swingable track wheel as well, it is very important to prevent a foreign matter from entering the space between the track wheel and the crawler.
However, in the conventional travel gear having the swingable track wheel
11
described in Japanese Unexamined Patent Application No. Sho-53-53843, although the crawler is prevented from coming off at the time of driving on uneven ground by the guide member
54
and elongated member
57
attached to the lower ends of the arms
53
and
56
which swing vertically so as to follow vertical movement of the crawler
6
, since no guard member is provided, intrusion of a foreign matter into the space between the track wheel
11
and the crawler
6
cannot be prevented. Consequently, there is a problem that wear of the crawler link and the track wheel
11
is severe due to the intrusion and the durability is not satisfactory. Since the two swingable track wheels
11
and
11
at both front and rear ends of the track frame
2
and the idler
3
are attached to both ends of the first arm
53
, by influence of the vertical movement of the idler
3
, the upper and lower positions of the swingable track wheels
11
and
11
at the both rear and front ends and the guide member
54
are determined. It is difficult to prevent coming-off of the crawler at both front and rear ends and intrusion of a foreign matter with reliability.
On the other hand, even if the fixed cover
51
integrally attached to the track frame
2
as used for the travel gear according to the first prior art disclosed in Japanese Patent Publication No. Sho-63-16313 is applied to the travel gear having the swingable track wheel, there is a problem such that when the track wheel
11
is lowered by the swingable arms
53
and
56
, the cover
51
cannot sufficiently prevent intrusion of a foreign matter.
As described above, also in the travel gear having track wheels which can swing vertically, development of a travel gear capable of preventing intrusion of a foreign matter into a space between the track wheel and the crawler is strongly demanded.
SUMMARY OF THE INVENTION
The invention has been achieved by paying attention to the problems and its object is to provide a travel gear of a crawler work vehicle capable of preventing intrusion of a foreign matter into a space between a swingable track wheel and a crawler.
To achieve the object, according to the invention, there is provided a travel gear of a crawler work vehicle, in which a pair of right and left track frames are provided in the longitudinal direction in the lower part of the vehicle and a plurality of double bogie type track wheel devices are attached in the lower portion of the track frames, each double bogie type track wheel device including: a first arm member attached to the lower part of the track frame so as to be swingable in the vertical direction; a second arm member of which almost center portion in the longitudinal direction is rotatably attached to a tip of the first arm member so that both front and rear ends of the second arm member are swingable in the vertical direction; and a pair of front and rear track wheels rotatably attached to the front and rear ends of the second arm member and rotating on a tread of a crawler rotatably wound around the track frames, wherein a pair of first guard devices for preventing intrusion of a foreign matter into a space between the pair of front and rear track wheels and the crawler are attached to both side faces in the width direction of the vehicle of the first arm member
Onohara Kazuyuki
Yoshida Tsuyoshi
Komatsu Ltd.
Stormer Russell D.
Varndell & Varndell PLLC
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