JLG 120-SXJ Service Manual - Manual (Page 60)

SECTION 4 - BOOM & PLATFORM
4-12 – JLG Lift – 3121810
h. Chain Anchors and Sheaves: An inspection of
the chain must include a close examination of
chain anchors and sheaves. Check chain
anchors for wear breakage and misalignment.
Anchors with worn or broken fingers should be
replaced. They should also be adjusted to elimi-
nate twisting the chain for an even load distribu-
tion.
Sheaves should be inspected for worn flanges,
which would indicate misalignment, and wear on
the outside diameter of the sheave. A worn
sheave can mean several problems, as follows:
1. Chains too tight.
2. Sheave bearings/pin bad.
3. Bent/misaligned chains.
Table 4-1. Chain Stretch Tolerance
CHAIN SIZE
PIN TO PIN
MEASUREMENT
ALLOWABLE
STRETCH
35.5 CM SPAN
0.50 in. (1.27 cm)
pitch
14 in. (36 cm) or
28 pitches
0.42 in. (1.07 cm)
0.625 in.
(1.59 cm) pitch
15 in. (38 cm) or
24 pitches
0.45 in. (1.14 cm)
0.75 in.
(1.91 cm) pitch
15 in. (38 cm) or
20 pitches
0.45 in. (1.14 cm)
1.00 in. (2.54 cm)
pitch
14 in. (36 cm) or
14 pitches
0.42 in. (1.07 cm)
1.75 in. (4.45 cm)
pitch
14 in. (36 cm) or 8
pitches
0.42 in. (1.07 cm)
2.00 in. (5.08 cm)
pitch
14 in. (36 cm) or 7
pitches
0.42 in. (1.07 cm)
Figure 4-5. Broken Chain Limit Switch Adjustment