IBM Selectric - Page 75

c. Form the front lug so that a clearance of .010"-.040" exists be-
tween the lug and the feed plate positioning lug when the RIGHT
HAND RATCHET IS FEEDING (Fig. 212C).
NOTE:
Avoid forming the ribbon feed plate positioning lug. since
breakage would require replacement of the entire feed plate.
FEED
PAWL
CENTERED
FIGURE 212. FEED PAWL
4. RATCHET DfTENT LEVER LUGS:
-
I
DETENT LUG-FORM
LEFT OR RIGHT
FIGURE 213. DETENT lUG
(LEFT TO RIGHT)
These should be formed as foll-
ows:
a. Left or right. so that the rib-
bon feed ratchet tooth over-
throws past the edge of the
detented lug by .020"-.050"
when hand cycling to the high
point of the ribbon feed cam
(Fig. 213).
b. Form
the detent lugs front
to rear so that the ribbon
feed pawl engages a ratchet
tooth by approximately 1!2
the depth of the ratchet
tooth (Fig. 214).
Note: The feed pawl spring lug should clear the teeth of the op-
posite ratchet by at least .015" when the feed pawl is being with-
drawn to the rest position at the end of an operation. Failure to
clear the teeth of the opposite ratchet under power may result
in a lockup and consequent failure of the ribbon feed operation.
1 !2 TOOTH SURFACE
ENGAGEMENT
DETENT lUG
FORM FRONT
OR REAR
FIGURE 214. DETENT LUG (FRONT TO REAR)
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