Duff-Norton SK6420-6 - Manual (Page 8)

19. Remove spring (61) from end of screw (62).
20. Remove intermediate cluster gear (33), intermediate
pinion shaft (32) and thrust washer (31).
21. Remove socket head cap screws (45), lock washers
(46) and disassemble motor (53) from housing
(42).
WARNING
Care must be taken not to damage motor lead wires.
22. Remove “O”-Ring (52) and rubber grommet (50).
23. Disassemble outer tube (55) and slip off over
translating tube and clevis (66).
24. Remove air vent (58) guide bushing (59) from outer
tube (55) and, if necessary, remove wiper
scraper (60) from guide bushing.
NOTE
If wiper scraper or guide bushing are not damaged they
should not be removed.
25. Remove set screw (68) from spacer nut (37) and
disassemble spacer nut (37) from screw (62) by
clamping screw (62) between soft jawed vise.
WARNING
Care must be taken not to damage bearing journal of
spacer nut (37).
26. Remove output gear (39), key (40), thrust washers
(35), thrust bearing (36), and gear spacer (43).
27. Remove ball screw (62), translating tube and clevis
(66) and nut (64) assembly.
28. Remove washer (44) from screw (62).
29. Remove set screws (65) from coupling (72).
30. Unthread coupling (72) from ball nut (64) and slide
translating tube (66) and coupling (72) off ball
screw (62). Unthread coupling (72) from
translating tube (66).
CAUTION
It is very important that the ball nut (64) not be allowed
to run off the ball screw (62).
31. Slide a tubular arbor (7/8 in. O.D. x 9/16 in. min. I.D.
x 5 in. min. length) over gear journal at end of
ball screw (62), hold against shoulder and
unthread ball nut (64) from ball screw (62) onto
arbor, then remove from ball screw being careful
that ball nut does not slide off arbor.
32. Secure ball nut (64) to arbor by taping or clamping
arbor ends or by applying a binding wire
through arbor.
33. If necessary remove cap screw (71), lock washer (70)
and stop disc (69) from ball screw (62) and
adapter (63) from housing (42).
34. Removing the brake (49) .(Required only if drift is
excessive. If brake removal is not necessary,
proceed to Step 35).
a. Push on the pinion (29) and coupling (47)
until it slips back enough to make the spring
(49) tang accessible.
b. Remove the spring (49) by grabbing the tang
with pliers and twisting out. (Spring must now
be replaced and can no longer be used.)
c. Remove the brake insert (51). Remove
retaining ring (48) from input pinion (29). Input
pinion (29) and bearing (30) can now be
removed from housing (42).
d. The brake inset (51) has straight knurls on its
O.D. which prevent it from rotating. Therefore,
the insert can only be removed by pulling
straight out.
e. One method of removing the insert (51) is to
use a blind hole bearing puller. This tool
expands into the internal spring cavity and pulls
against the lip of the insert (51).
35. If coupling (47) on motor (53) shaft must be
replaced, remove retaining ring (48) from motor
(53) shaft and remove coupling (47).
DISASSEMBLY IS COMPLETE.
4-5. ASSEMBLY
Assemble the actuator as follows while referring to
Figure 5-1. Read instructions thoroughly before
assembling.
NOTE
Be sure all components are clean and dry before
assembling.
1. Assemble coupling (47) on motor (53) shaft, then
install retaining ring (48) on motor shaft.
2. Press bearing (30) on input pinion (29) (press load
should be applied to inner race of bearing to
avoid damage to bearing).
3. Press bushing (34) and thread adapter (63) into
housing (42).
4. Install input pinion (29) – bearing (30) assembly in
housing (42) (press load should be applied to
outer ring of bearing to prevent damage to
bearing).
5. Assemble coupling (47) on input pinion (29) and
install retaining ring (48).
6. Brake Assembly
a. Grease O.D. of spring (49) and pocket of
insert (51) (chamfered end) with Exxon Ronnex
Extra Duty #1.
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DN-SK6420-6-1006 10/10/06 11:40 AM Page 8