JLG SSV10 Service Manual - Manual (Page 91)

SECTION 5 - MAST COMPONENTS
3121187 – JLG Lift – 5-19
5.10 MAST CHAINS AND SEQUENCING
CABLES ADJUSTMENT
NOTE: This procedure is to be performed with the mast
mounted on the machine.
Mast Chain/Cable Adjustment
(See Figure 5-8.)
The intention of this procedure is to assure equal load dis-
tribution between the individual chains of a mast section
chain sets.
Adjust using the following procedure;
1. Remove the mast cover from the platform. See Sec-
tion 5.2, Mast Cover - Install/Remove.
2. With mast completely lowered, step into the platform
and bounce your weight up and down a few times to
be certain platform is at the bottom of travel. Be cer-
tain the chain sets are seated in their sheaves prop-
erly at the top of each mast section.
3. Then with no load in the platform check the side pro-
file of the top of the mast, the mast sections should
all be even at the top and not stepped. (See Figure
5-8.)
4. If adjustment is required, adjust one mast section at
a time starting from the front of the mast (section-3)
and work towards the platform. (only mast section-3
and 4 are adjustable)
5. To adjust, elevate the platform until the chain anchor
adjust and jam nuts are accessible at the front and
bottom of each mast section.
NEVER WORK UNDER AN ELEVATED PLATFORM UNTIL PLATFORM
HAS BEEN SAFELY RESTRAINED FROM ANY MOVEMENT BY BLOCK-
ING OR OVERHEAD SLING.
6. Start with the mast section which needs adjustment
and loosen the bottom (jam) nut on each chain.
7. Tighten (to raise mast section), or loosen (to lower
mast section) the adjusting nut against the anchor
plate on each chain. Adjust the nut the amount
required to raise or lower the top of the mast section
to match the side profile shown in Figure 5-8. when
the mast is retracted.
NOTE: It is more important that the (threaded ends) studs
are equal side to side on a mast section, than it is
that the tension in the chains is equal. The chain
equalizers will always assure equal tension, but if the
adjustment isn’t equal as described, the chains may
tend to pull to one side or the other.
The threaded end of the chain may need to be
restrained while tightening the adjust nut to keep the
chain from twisting.
8. Retract the mast all the way and check if the top of
the mast sections appear as shown in Figure 5-8.
9. Repeat steps (1) through (7) for remaining mast sec-
tions.
10. Once mast section adjustment is completed, apply
loctite #242 to the threads under the (jam) nuts that
were loosened. Then re-tighten the loosened (jam)
nuts until tight against the top (adjust) nut. Chain
should have slight tension but should not be taut.
11. After all mast adjustments are complete, if neces-
sary readjust the bumpers mounted on the base
frame under the platform so the platform rests
slightly above the base frame when it is lowered and
empty.
Sequencing Cable Adjustment
1. Retract mast completely, and check each sequenc-
ing cable on outside of masts for excessive slack.
Adjust only to remove slack from cable.
2. Tighten nylock-nut, at the sequence cable bracket
located at the top of the mast, just enough to
remove excessive slack from sequencing cable. The
springs should not be compressed more than 25%
after adjusting.
NOTE: If slack cannot be adjusted out of the cable and
adjust nut has completely compressed the spring,
then either the mast side profile is not adjusted prop-
erly (even) or the the cable will have to be replaced
due to stretching.
After adjusting the mast chains and sequence cables,
cycle mast up and down several times to verify adjust-
ments are correct.