JLG 110HX ANSI Service Manual - Manual (Page 32)

SECTION 2 - PROCEDURES
2-8 – JLG Lift – 3120636
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, Chain
Stretch Tolerance for proper chain specifications
and allowable stretch tolerances. 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 pattern, is caused by misalign-
ment of the sheave/chain anchors and must be cor-
rected 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"