JLG 110HX Service Manual - Manual (Page 32)

SECTION 2 - PROCEDURES
2-8 – JLG Lift – 3120864
An immediate disassembly of the boom assembly and
inspection of the boom chains and related components is
required if any of the following conditions occur:
1. After the machine is exposed to hostile environ-
ments or conditions (i.e. extreme cold, dust, sand,
blasting grit, salt, chemicals, etc.), which could
adversely affect boom operation.
2. Erratic boom operation or unusual noise exists. See
the Troubleshooting section in this Service Manual.
3. Chain adjustment is required more often than speci-
fied in the Preventive Maintenance and Inspection
Schedule or links need to be removed (chain short-
ened) to make the proper adjustment.
4. The machine is idle for an extended period (6
months or longer.)
5. The boom is overloaded or sustained a shock load.
FAILURE TO DISASSEMBLE THE BOOM ASSEMBLY AND PROP-
ERLY INSPECT AND/OR REPLACE THE BOOM CHAINS AND
RELATED COMPONENTS (I.E., SHEAVES, PINS, SPROCKETS,
WEAR PADS, ETC.) COULD RESULT IN THE DAMAGE AND/OR
BREAKAGE OF THE BOOM CHAINS AND/OR RELATED COMPO-
NENTS. DAMAGE AND/OR BREAKAGE OF THESE ITEMS COULD
RESULT IN UNCONTROLLED EXTENSION OR RETRACTION OF
THE BOOM ASSEMBLY AND COULD CAUSE SERIOUS INJURY OR
DEATH TO PERSONNEL OPERATING THE JLG BOOM LIFT.
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Inspection Procedure
Inspect boom chains for the following conditions:
1. Wear: Always inspect that segment of chain that
operates over a sheave. As the chain flexes over the
extend/retract sheaves, joints and plate edges very
gradually wear. Chain “stretch” can be measured
using a manufacturers wear scale or steel tape.
When chains have elongated 3% they must be
removed and replaced. Refer to Table 2-1 for proper
chain specifications and allowable stretch toler-
ances. Peening and wear of chain plate edges are
caused by sliding over a chain worn contact face of
a sheave, or unusually heavy loads. All of the above
require replacement of the chain and correction of
the cause. Chain side wear, noticeable when pin
heads and outside plates show a definite wear pat-
tern, is caused by misalignment of the sheave/chain
anchors and must be corrected promptly. Do not
repair chains; if a section of chain is damaged,
replace the entire chain set.
H for a 1" chain
Maximum wear
Minimum plate depth = 0.950"
= 5% of 0.950" = 0.047"
= 0.950" - 0.047" = 0.903"