4000 SRM 764
Mast Adjustments
Mast Adjustments
NOTE:
Each load roller is kept in the correct posi-
tion on the stub shaft using shims. The shims are in-
stalled on both sides of the load roller. Do not add or
remove shims from the stub shafts. To change the po-
sition of the roller on the stub shaft, move the shims
from one side of the roller to the other.
During assembly, the shim arrangement will be ap-
proximately the same as before disassembly. Make
notes of each shim arrangement during disassembly.
Check the clearance and adjust for wear or change
from the repairs. See Figure 14.
1.
The load rollers control the alignment of the
masts. The alignment conditions are given in
the steps following this paragraph with the most
important condition first.
• The vertical mast weldments must be parallel
to each other to decrease wear.
• The maximum clearance between the load
roller and the mast weldment at the POINT
OF TIGHTEST FIT is 0.8 mm (0.031 in.).
• The number of shims between the roller and
mast weldment on a stub shaft must be approx-
imately the same as the stub shaft in the oppo-
site channel. The mast weldments will be ap-
proximately in the center.
2.
Use the following procedure to adjust the load
rollers for the mast:
a. Use a crowbar to move the mast weldments
from side to side to measure the amount of
movement. Repeat in a minimum of three
different positions of the mast weldments.
b. Separate the masts and change the shim ar-
rangements as needed. Assemble the mast
weldments. Slide the mast weldment all the
way to the top and bottom to find the tightest
fit.
c.
Repeat Step a and Step b until the clearance
is not more than 0.8 mm (0.031 in.) at the
point of tightest fit.
d. Measure the distance on the top and bottom
between the mast weldments. Move shims
from one side of the roller to the other to keep
the distance equal between the top and bot-
tom so the masts are parallel.
3.
Adjust the strip bearings. Insert shims between
the strip bearing and the mast weldment. Ad-
just the clearance until there is less than 0.8 mm
(0.031 in.) at the point of tightest fit.
4.
Slowly raise and lower the mast several times
without a load. The mast components must raise
and lower smoothly in the correct sequence. The
inner mast weldments and the carriage or oper-
ator platform must lower completely.
NOTE:
Some parts of the mast move at different
speeds during raising and lowering.
1.
LOAD ROLLER
2.
WEAR PLUG
3.
STUB SHAFT
4.
ELEVATING MAST
5.
SETSCREW
6.
NUT
7.
SEALED
BEARINGS
Figure 14. Load Roller and Wear Plug Assembly
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