Duff-Norton Machine Screw Translating 2 Ton - 75 Ton - Manual (Page 5)

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4. Remove gear (6A) or worm gear and nut assem-
bly (6B) from shell (3).
Note
To facilitate removal of the gear from the shell
on models with 50- ton or higher load ratings,
partially reassembly the lifting screw into the
worm gear (or worm gear and nut assembly)
and use a hoist or pulley block to lift on the
screw.
5. Remove top load bearing (7) which may be
attached to either shell cap (2) or worm gear
(6A) or anti-backlash nut.
Note
Use only a soft face hammer to tap bearings
loose.
6. Remove bottom load bearing (8) which may be
attached to either the shell (3) base plate or
worm gear (6A).
7. Remove four cap screws (9) from each of the
two worm flanges (11) and remove flanges.
Note
Be careful not to lose flange shims (12).
8. Press oil seal (13) out of flange (11).
9. Remove worm (14) and worm bearings (15)
from shell (3) by striking one end of worm with a
soft face hammer.
10. Remove worm bearings (15) from worm (14)
with bearing puller or press. (Note: This step will
not be necessary if worm or worm bearings are
not damaged.
11. If actuator is keyed, remove screw in shell cap
and tap key out of keyway.
2-5. Cleaning
1. Use degreasing solvent to remove grease or oil
from all parts.
Note
Remove grease from unit and do not reuse old
grease.
WARNING
Provide adequate ventilation during the use
of cleaning agents; avoid prolonged breath-
ing of fumes and contact with skin. Read &
follow manufacturer's instructions.
2. Use clean hot water or a soap solution for
general cleaning of painted surfaces.
3. Dry parts thoroughly after cleaning.
Note
Before installing new parts, remove any rust
preventive, protection grease, etc.
2-6. Inspection (Refer to Figure 3-1)
Inspect actuator parts as follows:
1. Make a visual inspection of shell (3) for broken,
cracked or distorted areas. Check threads of all
bores for burrs or broken threads.
2. Check shell cap (2), base plate, bottom pipe (4),
lifting screw (5), worm gear (6A) or worm gear
and nut assembly (6B) for burrs or scratches on
their working or mating surfaces.
3. Check fit between lifting screw thread and
internal thread in worm gear. If fit is excessively
loose, replace worm gear or lifting screw as
required. Replace worm gear and nut assembly
as a set [4800 (5800) and 9400 (10400) Se-
ries].
4. Check small common components (screws, etc.)
and replace as required.
5. Check bearings (7), (8) and (15) for seizure,
galling or play and replace as required.
2-7. Assembly (Refer to Figure 3-1)
1. Press worm bearings (15) onto worm shaft (14),
making sure that bearings are seated properly
against shoulder.
Note
When tapered roller bearings are used, the
small end of the cone should point to the worm
end.
2. Position worm shaft end (14) in shell (3).
Note
If tapered roller bearings are used, tap worm
bearing cups into place in the shell.
3. Press oil seals (13) into worm flange (11).
Note
The sealing element should point inward.
4. Position worm flanges (11) with shims (12) and
bolt in place.
5. Position bottom load bearing (8) or bearing cup
in shell (3).
5a. On 5-ton, 35-ton and 75-ton models, press load
bearing cones onto worm gear (6A) or worm
gear and nut assembly (6B).
6. Install worm gear (6A) or worm gear and nut
assembly (6B) in shell (3).
Note
Strike each end of worm shaft sharply with a
soft face hammer to seat bearing properly.
Recheck flange bolts for tightness. Worm should
turn freely with minimum drag and end play. If
too much end play is present, remove shims as
required. If worm does not turn freely, add shims