SkyTrak 6042 Operation Manual - Manual (Page 169)

General Maintenance
167 Model 6042 Origin 2/04
Cracked Plates
Inspect the chains very carefully, front and back as well as side to side,
for any evidence of cracked plates. If any one crack is discovered, the
chain should be replaced in its entirety.
It is important, however to determine the cause of the crack before
installing a new chain so the condition does not repeat itself.
The types of cracks are:
• Fatigue Cracking - Fatigue
cracks (5) are a result of
repeated cyclic loading beyond
the chain’s endurance limit.
• Stress Corrosion Cracking -
The outside link plates are
particularly susceptible to stress
corrosion cracking (6).
• Corrosion Fatigue Cracking - Corrosion fatigue cracks are very
similar to fatigue cracks in appearance. Corrosion fatigue is the
combined action of an aggressive environment and cyclic stress.
Other Modes of Failure
• Ultimate Strength Failure -
These types of failures are
caused by overloads far in
excess of the design load.
Either fractured plates (7) or
enlarged holes (8) can occur. If
either of these failures occurs,
the chain should be replaced
immediately.
• Tight Joints - All joints in
the chain should flex freely.
Tight joints (9) resist
flexing.
If the problem is caused by
dirt or foreign substance
packed in the joints, clean
and lubricate thoroughly before re-installing the chain.
If the problem is caused by corrosion and rust or bent pins,
replace the chain.
MM2070
5
MM2080
6
MM2100
7
MM2090
8
MM2110
9