IBM Selectric Maintenance Manual page 57

Carrier Return
Latch Arm
Bracket Assembly
Eccentric Should
.-.l:=;'--I~", Up And T ouch-
ing Latch Bracket
FIGURE 104. Pivot Pin Eccentric
(Early Level Machines Only)
NOTE: The eccentric may require a readjustment if
the rest position of the pivot pin is changed during car-
ri er return adj ustments •
6. Escapement Cam - Adjust the cam by rotating it on the
filter shaft so that the cam follower roller just reaches
the low point of the cam at the rest position (Fig. ·105).
The cam is accessible from the top by inserting the fluted
wrench between the carrier return and backspace key-
levers just in front of the margin rack. (The keylevers
are not present on all printers.)
Check the adjustment by holding the cycle clutch check
pawl out of the way so that the cycle shaft can be ro-
tated backward. Rotate the filter shaft gear backward
slightly and observe that the escapement trip link moves
forward immediately. This will insure that the escape-
ment cam is not resting past the low point. To insure
that the cam follower has fully reached the low point,
hand-cycle a print operation. The escapement trip link
should not move during the first part of the cycle.
The cam adjustment affects the timing of the print es-
capement. Advanced timing could cause the trip to oc-
cur before the print action, resulting in crowding or
blurring of the printed characters. Retarded timing will
cause the cam follower to rest part of the way up the
incline of the cam. This could restrict the escapement
trigger from the resetting over the torque bar lug as the
fi Iter shaft returns to its rest position.
7. Escapement Trip Link - Adjust the trip link so that a
clearance of .007" to .010" exists between the torque
bar lug and the hook of the escapement trigger in the
rest position (Fig. 105) .
CAUTION: In adjusting the escapement trip link be
sure that the trigger lever upstop (Fig. 107) and the
adjustment screw in the spacebar latch lever«Fig. 136,
page 41) do not restrict the upward travel of the
trigger lever.
The adjustment insures that the torque bar will always be
rotated far enough to trip the pawls from their racks.
If excessive clearance is present, the escapement may
eventually fai I as wear occurs in the system and reduces
the amount of travel given to the trigger.
Insufficient clearance may prevent the trigger from re-
setting over the torque bar lug at the end of each cyc Ie.
It may also cause the escapement trip to occur too early
in the cycle. The trip should not occur before the print
action.
8. Escapement Trigger Action - Adjust the trigger guide
(early style machines) or the trigger knock-off eccentric
stud (new style machi nes) so that the escapement trigger
wi II become disengaged from the torque bar lug when
the escapement pawl clears the rack by .010" to .015"
(Fig. 106).
Cam Follower Just Resting At Low Point
FIGURE 105. Escapement Cam And Link Adjustment
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