The track frame, as the name implies, serves as a
framework and support for the track assembly, rollers,
front idler, recoil spring, and adjusting mechanism.
Track frame alignment may be fixed or shim
adjusted depending on the manufacturer. When shims
are used, there are a couple of ways alignment may be
maintained. One way is using shims where the frame
attaches to the rear pivot and also near the center of the
track frame where it is mounted against the main frame
guide brackets. Another way is to use a diagonal brace
and shims at the rear pivot to align the track frame.
Track Frame Rollers
Two types of track frame rollers are used on
tracked equipmentthose located on the lower
portion of the track frame which supports the weight of
the tractor, and those above the track frame which
supports the track assembly, as it passes over the track
Carrier rollers (fig. 6-24) are single-flanged
rollers mounted on brackets, which extend
above the track frame and supports the track
assembly. Two of these rollers are on each side
of the tractor. The flange extends upward
between the links of the track chain. keeping the
chain in alignment between the drive sprocket
and the front idler.
Track rollers (fig. 6-25) are double- and single-
flanged rollers that supports the weight of the
tractor, ensures that the track chain is aligned
with the track frame at it passes under the rollers,
and prevents side to side track movement and
derailment. In a normal arrangement, a double-
flanged roller is directly in front of the drive
sprocket, followed by a single-flanged roller.
The rollers alternate forward to the front idler.
The front idler, as shown in figure 6-25, serves as a
guiding support for the track chain. The idler is spring-
loaded and mounted on slides or guides that allow it to
move back and forth inside the track frame, as the
tractor passes over uneven terrain. The spring loading
Figure 6-25.Track rollers in position in the track frame..
Figure 6-24.Track carrier rollers.