Maintenance Section
-168-
Lift Chains - Test, Check, Adjust
Lift Chain Wear Test
Inspect the part of the chain that is normally operated
over the cross head roller. When the chain bends
over the roller, the movement of the parts against
each other causes wears.
Inspect to be sure that chain link pins do not extend
outside of the link hole. If any single link pin is
extended beyond its connecting corresponding link,
it should be suspected of being broken inside of its
link hole. Lift chains are required to check for wear
about every 1,000 service hours or 6 months.
Chain wear test is a measurement of wear of the
chain links and pins. Take the following steps to
check chain wear.
1. Lift the mast and carriage enough for getting
tension on lift chains.
Typical example
2. Measure precisely ten links of chain distance at
the center of pins in millimeter.
3. Calculate chain wear rate*.
4. If the chain wears rate is 2% or more, replace
the lift chain.
*Chain wear rate (%)
= Actual measurement - Pitch** X 10
Pitch** X 10
1) FOR STD, FF, FFT MAST 19.05mm(0.75 in) for
2~3 ton truck.
25.4mm(1 in) for 3.3~Light 3.5 ton truck.
2) FOR QUAD MAST (for 2.5 ton)
19.05mm(0.75 in) for inner mast chain.
25.4mm(1 in) for carriage and outer mast chain.
Check for Equal Tension
Typical example
Lift the carriage and the mast high enough for getting
tension on lift chains. Check the chains, and make
sure the tension is the same. Lift chains are required
to check for equal tension about every 1,000 service
hours or 6 months.
WARNING
Personal injury can be caused by sudden
movement of the mast and carriage. Keep hands
and feet clear of any parts that can move.
Lift Chain Adjustment
Typical example for carriage equal tension
If the tension is not the same on both chains, take
the procedure as follows.
NOTE:
If carriage height is not correct, make
adjustments by following procedures.
x100
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