28
LIFT CHAINS AND SLIDE BLOCKS
WARNING
Do not operate a unit on which any chain
assembly is damaged or in need of replacement.
Operating a unit with a damaged chain can
cause severe injury or death to personnel and
damage to equipment.
Inspect all lift chains every 6 months. Inspect for
signs of wear, split leaves, loose pins, clevis
damage, and elongation. Replace any chain that is
damaged in any way. Chain assemblies may be
ordered from your dealer or direct from the factory.
Do not operate a unit on which any chain assembly
is damaged and in need of replacement.
Chain Elongation Inspection
Refer to Figure 4-11. Measure 20 pitches of chain.
Twenty pitches of new chain should measure 12.5
in. (31.75 cm). Replace the chain if a 20-pitch length
measures over 12.75 in. (32.385 cm).
Figure 4-11. Chain Elongation Inspection
Lift Chain Adjustment
Raise the platform to the maximum height.
Then, lower the platform while someone verifies
that all sheaves (pulleys) are turning and that
the chains are not visibly damaged or worn.
Remove the plexiglass cover from the base.
When the platform is fully lowered, the lift chains
should be equally tight. Check each lift chain at
mid-span. The lift chains should flex about 1/2 to
3/4 inch (12 to 19 mm), but there should be no
loose play.
If a lift chain is loose, tighten the related clevis,
Figure 4-12. Tighten the clevis lock nut until the
lift chain just becomes snug. Do not over-tighten
any lift chain. (An over-tightened lift chain will
raise the platform from its rest position at the
bottom of the base slide ways).
After making a lift chain adjustment, verify that at
least 1/8 in. (3 mm) of the threaded clevis rod
extends beyond the lock nut. Also recheck the
slack of all lift chains at mid-span; verify that all
lift chains are equally snug.
If a single lift chain requires frequent adjustment,
the clevis lock nut is probably worn. Replace any
clevis lock nut that does not hold position during
use.
Replace the plexiglass cover.
LIFT
CHAINS
LIFT
CHAINS
LOCK
NUT
LOCK
NUT
CLEVIS
CLEVIS
Figure 4-12. Lift Chains Adjustment.
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