Maeda MC405C-3 - Page 284

Section 5 – INSPECTION Mini-Crawler Crane M A E D A
5-32 1/2019 MC405C-3
Especially, with the new machine or when a new
part was installed, "initial slack" appears with 5 to
30 hours of operation after adjusting the tension
to the specified value.
Adjust the tension frequently until the period of
"initial slack" passes. This will prevent "rubber
track from coming off due to insufficient tension
on the rubber track".
Tension Check
1. Move the left and right crawlers so that the
junction of the rubber track (indicated by M)
comes to the top centre between the axles.
Fig. 5-57
2. See "OUTRIGGER SETTING" on page 4-42
to set the outriggers and raise the crawlers
for about 50mm from the ground.
3. Measure the clearance between the wheel
tread of the track roller at centre and the
shoulder of the rubber track.
NOTICE: The clearance of 5 to 10 mm indicates
the standard tension.
Fig. 5-58
4. If the tension is out of the standard range,
see "Tension Adjustment" below to make
adjustments.
Tension Adjustment
If the "tension check" of the rubber track found
the tension lower than standard tension of the
rubber track, make adjustments as described
below.
Working with the loose rubber track (the tension
of the rubber track at 15 mm or more) will cause
run-off or early wear of the core metal.
• Loose Tension (Increase Tension)
Have a grease gun (pump) ready.
1. Inject the grease from the grease valve (1)
using the grease gun.
Fig. 5-59
2. Perform the following tasks to verify the
proper tension.
(1) See "OUTRIGGER STOWING" on page
4-49 to stow the outriggers and lower
the machine on the ground.
(2) Move the machine forward/backward.
(3) See "OUTRIGGER SETTING" on page
4-42 to set the outriggers and raise the
crawlers again for about 50mm from the
ground.
3. Perform the "tension check" of the rubber
track again.
If the tension is not appropriate, make
another adjustment.
4. See "OUTRIGGER STOWING" on page 4-
49 to stow the outriggers and lower the
machine on the ground.
• Tight Tension (Decrease Tension)
WARNING! Inside the rubber track tension
adjustment device has the grease sealed. The
grease is under high pressure due to the
tension of the rubber track.
Making adjustments without observing the
followings may cause the grease valve to fly
away, resulting in serious accidents.
• Do not loosen the grease valve for tension
adjustment for more than 1 turn. The grease
valve may pop out.
• Do not place yourself right in front of the
grease valve when adjusting the tension to
avoid any danger.