Operational Magnet Assembly - IBM Selectric Maintenance Manual

NOTE: The operational clutch ratchet must be posi-
tioned laterally on the operational shaft so that each
clutch release arm will take an equal lateral bite on its
respective clutch wheel. This insures that neither clutch
release arm can slip sideways off its respe.o.tive clutch
wheel causing an unwanted cam operation. This condi-
tion is most serious on the carrier return/index cam as it
will cause an index operation to occur each time the
cam is released.
7. Clutch Release Arm (Fig .119)- The lug at the bottom of
each clutch release arm should be formed so that it clears
the interposer lug by .025" to .035" on Carrier Return,
Index and .035" to .045" on Tab, Backspace, and
Spacebar.
C.R., Index
FIGURE 119. Clutch Release Arms Adjustment
NOTE: The interposers and cams must be latched when
the adjustment is observed.
Insufficient clearance wi II cause the cams to be released
too early in the rearward travel of the interposers; con-
sequently the operational latch involved will not have
sufficient bite on the cam follower lever as it is operated
down at the rear. The operational latch may slip from
beneath the cam follower and result in an incomplete
operation . Excessive clearance could allow the inter-
poser to reach the limit of its travel before
the
cam is
released.
NOTE: The clearance may be judged with the use of
the push end of the large spring hook. The end of the
spring hook is approximately .035" thick.
8. Interposer Restoring Bail - Form the lug at each side of
the restoring bai I so that the interposers wi II be restored
forward .010" to .030" past the latching point (Fig. 120)
when either cam is operated. Be sure to check the in-
terposers at
ea~h
side and form the lug on the side being
checked.
The adjustment insure positive relatching of the inter-
posers without excessive overthrow. Excessive overthrow
can cause an interposer to take an extra cyc Ie.
NOTE: The lugs should be formed forward or back to
obtain the adjustment. Forming the lugs forward in-
creases the throw of the interposers. Too much forming
wi II cause them to break.
.010" to .030"
FIGURE 120. Interposer Restoring Bai I Adjustment
OPERATIONAL MAGNET ASSEMBLY (EARLY STYLE)
2-38
1. Tab, Backspace, and Index Magnets (Fig. 121 & 122) -
a. Backspace Pivot Plate - Position, vertically, so
that the armature {manually attracted} clears its
yoke by .001" to .003" {a II three screws must be
loose}. Position, horizonta"ily, so that all armatures
center thei r yokes.
b. Pivot Plate - Tighten the backspace pivot plate
screw and position so that the left and right arma-
tures clear their yokes by .001" to .003".
Pivot P late Screws
FIGURE 121. B/S Pivot Plate Location
Armature
FIGURE 122. Backspace Pivot Plate