IBM Selectric - Page 17

b. Adjust the detent actuating lever support front or
rear (unde r its lock i ng screw) so that the rotate
detent will clear the teeth on the type head ski,t
by .025
11
to .035
11
when the cycle shaft is at rest
(Fig. 41). This clearance shovld be observed:n
the type head is manually ti Ited to a two ti It '::'0-
sitionsince the two tilt position provides the ;~!..iH;
detent with the least amount of mrAio(
.025" To .035"
FIGURE 41. Skirt Clearance
Moving the actuating lever support to the rear wi II
increase skirt clearance.
c. With the detent cam follower on the low dwell of
the detent cam (detents full y seated) rotate the
actuating lever support unti I .001
11
clearance is
felt between the detent actuating lever and the
detent cam follower roller. Rotating the support
clockwise wi II increase the clearance.
NOTE: T he ad j ustments of the detent mec han i sm di rect I y
affecteachotherandmust be adjusted alternately to ob-
tain the correct clearances.
The .001" lost motion adjusted into the system between
the detent actuating lever and the detent cam follower
insures that the tilt detent will fully seat in the detent
notch of the tilt ring. Too much clearance would allow
the detents to enter their notches too early and withdraw
too late. This could cause an intermittent erroneous
character to print, parts breakage, or roller droppage in
wear compensator.
The .02511 to .035
11
skirt clearance allows the rotate
detent to enter and withdraw from the type head notch
area at the proper time with respect to the rotatin!;l type-
head. Ifthisclearance is too small the rotate detent will
enter the notch area too early and withdraw too late.
This will also cause an intermittent erroneous character
to print, parts breakage, or unwanted roller droppage.
Toomuchskirtclearance will only cause premature wear
on the detent mechanism due to the leverage gain.
Since the detent cam and print cam are both keyed to the
print shaft, the relationshi p between the detent timing
and the point at which the type head prints is non-
adjustable. The designs of the two cams is such that the
detents will be fully seated in their notches when the
type head contacts the platen during a print operation.
The only thing that can effect this timing relationship is
the position ofthe detent cam follower mounting bracket.
The position ofthis bracket is fixtured at the factory and
should not be changed.
15
11. Detent Mechanism (Gearless Tilt)
The
detent mechanism must be adjusted to satisfy the fol-
lowing conditions:
a. With the cycle shaft at rest and the typehead man-
ually held in a two tilt position, adjust the ribbon
feed and detent cam left or right on the print sleeve
(Figure 42) so that the rotate detent wi II clear the
detent teeth on the type head ski rt by .025" to .035
11
(Fig. 43).
Position Left or Right
Ribbon
Feed And Detent Cam
FIGURE 42. Detent Cam Adjustment
Moving the cam to the left wi II increase the clear-
ance.
.025" To .035"
1 __
-r-
FIGURE 43. Skirt Clearance
b. With the detent cam follower on the low dwell of
the cam (detents fully seated), loosen the locknut
on the detent actuating lever support and adjust
the Bristo screw upordown until there is a clear-
ance of .00111 felt between the detent actuating
lever and the detent cam follower roller (Fig. 44).
Adjusting the Bristo screw up will increase the
clearance.
NOTE: Read the II note II under Adjustment #9 as it per-
tains to the gearless tilt mechanism also.
Coarse AI ignment
1. Preliminary Print Shaft Timing - With the cycle shaft
latched in its rest position, loosen the print shaft gear
and rotate the pri nt sha ft so that the keyway is approxi-
matelyin linewiththeendofthe ribbon liff cam follower
pivot screw (Fig. 45). The keyway wi II be about 45°
to the rear from the top of the shaft.