IBM Selectric Reference Manual page 48

Moving the actuating lever support to the rear will
increase skirt clearance.
c. With the detent cam follower on the low dwell of
the detent cam (detents fully seated) rotate the
actuating lever support until .001 11 clearance is
felt between the detent actuating lever and the
detent cam follower roller. Rotating the support
clockwise wi II incredse the clearance.
NOTE: The adjustments of the detent mechanism directly
affect each other and must be adjusted alternately to ob-
tain the correct clearances.
The .00111 lost motion adjusted into the system between
the detent actuating lever and the detent cam fol lower
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 the i r notches too earl y and wi thdraw
too late. This could cause an intermittent erroneous
character to print, parts breakage, or roller droppage in
wear compensator.
The .025" 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 rotating type-
head. Ifthisclearance istoosmall 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.
Toomuchskirt clearance 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 relationship 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 affect this timing relationship is
the position of the detent cam follower mounting bracket.
The position ofthis bracket is fixtured at the factory and
should not be changed.
1.1. Detent Mechanism (Gearless Ti It)
The detent mechanism must be adjusted to satisfy the
following 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
(Fig. 103) so that the rotate detent will clearthe
detent teeth on the typehead ski rt by .025 11 to .035 11
(Fig. 104).
Moving the cam to the left wi II increase the clear-
ance.
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 up or down unti I there is a clear-
ance of .001" felt between the detent actuating
lever and the detent cam follower roller (Fig. 105).
2-30
FIGURE 103. Detent Cam Adjustment
.025" to
FIGURE 104. Skirt Clearance
Loose n Loc k nu t
------I"::IX:n....Jiiiiiiiiiiiil~
I
FIGURE 105. Detent Lever Support
Adjusting the Bristo screw up will increase the
clearance.