Track systems also come in what is commonly called a sealed system, where the pin
and bushing are lubricated on assembly and are sealed from dirt entering between
them. This design eliminates internal wear.
Track shoes are bolted to the link assembly to provide a means of supporting the
equipment and better traction and flotation during operation. They are generally
constructed from a hardened metal plate and come in many different configurations.
Refer to
Figure 9-29
for design features of a track shoe. The operating ground
conditions will determine the type of shoes to be used. Operation on highly abrasive soil
demands a high quality, hardened surface that will resist wear. The number of ridges
(called grousers) on the track shoe designates the terrain on which the shoe will
operate. The hardness of the surface material on the grousers determines whether they
are standard or extreme-service track shoes.
Figure 9-29 -
Track shoe.
Track Links, Pins, and Bushings.
Each track section is made up of two track links
(
Figure 9-30
), a hardened pin, and bushing. These individual track sections are
interconnected to the link assembly. The two track links used in a section have
provisions for attaching a track shoe and also provide a rail for the track rollers to
maintain accurate track alignment. Sealed tracks have a solid pin. Sealed and
lubricated tracks have a hollow pin, which provides a path for lubricating the pin and
bushing of the next track section (
Figure 9-31
). When installing a center-drilled pin, the
cross drill hole must be installed toward the rail of the link, which keeps the pin in
compression to resist the possibility of crushing. The pins and bushings are press-fit into
the links. Be sure to follow the correct orientation; there are both right-hand and left-
hand hand links. Clearance between the pins and bushings is minimal, providing only
enough clearance for lubrication. In the case of a sealed track, the seal fits over the pin
against the track link before installing another link.
NAVEDTRA 14050A
9-37