SkyTrak 10054 Operation Manual - Manual (Page 174)

172 Model 10054 Rev 3/02
General Maintenance
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 (1) 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 (2).
• 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 (3) or
enlarged holes (4) 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 (5) 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
1
MM2080
2
MM2100
3
MM2090 4
MM2110
5
172
Model 10054 Rev 3/02
General Main tenan ce
Crac kedP lates
Insp ect the chain sv ery car efully ,fr ont andbac ka sw ell as sid et os id e,
fo ra ny ev id en ce of cra ck ed plat es .I fa ny one cra ck isdi scove red, th e
cha in sho uld ber eplac edi ni ts entir ety.
it is imp ortan t,how eve rt ode termi nethe cau seof the crac kbe fo re
ins tal ling ane wc hain so the con dition does notr epea ti tsel f.
Th et ypes ofcra cks are:
• Fat ig ue Crac kin g- Fa tig ue
crac ks (1 )a re ar es ult of
re peate dc yclic loadi ngbe yond
the chai n’s endu rance lim it.
• Stres sCo rro sion Crac king -
Th eo utsi deli nkpl atesar e
par tic ular ly susc eptib le tos tres s
corro sio ncr ack ing (2 ).
• Corrosion Fa tigueCr ac king -C orrosi onf atigue crac ks are ver y
sim ila rt of atig uec rac ks inappe arance .C orro sion fa tigue is the
comb in ed acti on of anag gre ssi ve envi ronm en ta ndcy clic str es s.
OtherM odeso fF ailur e
• Ult imat eS trengt hF ailure -
The se ty pesof fa ilur esar e
cau sed by ov erload sf ar in
ex cess ofthe desig nl oad.
Eith erfr actur ed plate s( 3)o r
enla rg edhol es( 4) ca noc cur .If
eith erof thes ef ailur es occ urs ,
the chai ns hould ber epl aced
imm ediatel y .
• TightJoints -A llj oin tsin
the chai ns hould fle xfr eely .
Tight joints (5) res ist
fle xing.
Ifthe prob lemis cau sed by
dirt orf orei gn su bs ta nce
pa ck ed in th ej oin ts ,c le an
and lubr ic atethor oughl ybef ore re- ins tal ling the chai n.
Ifthe prob lemis cau sed by cor ro sio nan dr ust or bent pin s,
repl ac et he chai n.
MM2070
1
MM 2080
2
MM 2100
3
MM2090 4
MM2110
5