333
M7.5-18.0-001
08 Rev. 7/07
LIFTING MECHANISM
Lift Chains
Lift Chains
Lift chains are highly important components on fork lift
trucks. The chain system on your mast was designed
for efficient, reliable transmission of lifting force from
hydraulic cylinder(s) to the mast, platform (if present)
and forks. Safe, uninterrupted use of your lift truck de-
pends on the proper care and maintenance of the lift
chains.
Most complaints of unsatisfactory chain performance
can be traced directly to inadequate maintenance.
Highly stressed precision chains require periodic main-
tenance to deliver maximum service life.
Inspection
After every 100 hours of truck operation, lift chains
should be inspected and lubricated. When used in an
extremely corrosive environment, inspect chains every
50 working hours. During inspection, check for the fol-
lowing:
Wear
As the chain flexes on and off pulleys, the joints gradu-
ally wear.
The "stretch" a chain develops during usage is due to
material being worn off of pin outside diameter and pin
hole inside diameter on the inside plates.
Chain wear can be measured by using a 106440 wear
scale or a steel tape (Refer to Figure 16844). When
chains have elongated 3%, as represented on scale
"A" (19 mm [0.75 in] or 25 mm [1.0 in] pitch chain) or
scale "B" (16 mm [0.625 in] pitch chain) of the wear
scale, they should be discarded. On chain with 19 mm
(0.75 in) between pins, for example, 305 mm (12.0 in)
of chain contains 16 pitches or links. When 16 pitches
measure 314 mm (12.375 in) the chain should be re-
placed. On chain with 16 mm (0.625 in) between pins,
20 pitches or links equal 318 mm (12.5 in). When 20
pitches measure 327 mm (12.875 in) the chain should
be replaced. Crown currently uses 16 mm (0.625 in)
pitch (20 links in 318 mm [12.5 in]), 19 mm (0.75 in)
pitch (16 links in 305 mm [12.0 in]) and 25 mm (1.0 in)
pitch (12 links in 305 mm [12.0 in]) chain. When check-
ing chain wear, be sure to measure a segment of chain
that operates over a pulley. Do not repair chain(s) by
cutting out the worn section and splicing in a new
piece. If part of a chain is worn, replace lift chain(s). If
truck has a matched set of lift chains replace both
chains at same time.
Figure 16844
Roller and Leaf
Chain Wear Scale
Crown 1984 PF5856-1 Rev. 7/07
To Next Page
Loading...