IBM Selectric - Page 51

2.
The latch height adjustment insures maximum throw tor
the latch and that it wi II move unde~ the cam fo! 'O"Ner
freely.
CAUT ION: Any change in the carrier ieturn kt d. "It': J~,t
directly affects the front to rear position of the !otr.h
(with respect to the com follower) when the machine is
at rest. See adjustment #4 in the Operational Control
section.
Pawl Clearance - Form the carrier return clutch latch so
that the escapement pawl will clear the rack teeth by
.005
11
to .015" when the latch is being held down by
the keeper (Fig. 143).
.005" To .015"
'~,~. ~~
V~~
Carrier Return Clutch
Latch
3.
Carrier Return
Latch Keeper
FIGURE 143. Pawl Clearance Adjustment
The adjustment insures that the escapement pawl wi II not
dragalongthe rock during a carrier return operation and
that the pawl will be allowed to re-enter the rock quickly
at the completion of the return operation.
Clutch Latch Overthrow - Install the platen and feed
rolls, and place the index selector lever in the double
index position before making this adjustment. This will
permit the adjustment to be measured while the system
operates under a load.
Manuallyoperate the carrier return com to its high poini
while observing the motion of the clutch latch. It should
overthrow the latching surface of the keeper by .030"
to .040". Adjust the carrier return latch arm adjusting
screw to obtain this condition. (For Model 721, see
Fig. 144. For Model 723 or 725, see Fig. 145.)
NOTE: On long carriage machines, make certain that
the carrier return latch hangs vertical without binding
laterally against its interposer. The carrier return lever
may be adjusted laterally on the latch actuatin~ arm
pin. Be sure to ti ghten the Bristol screw in the lever
onto the flat portion of the pin.
50
Adjusting Screw
Carri er Return
Latcn Arm
o
FIGURE 144.
Carrier Return
Clutch Latch
.030" to .040;1 Clearance
At This Point
Clutch Latch Oveythrou)
Adjus tment (721)
Adjusting Screw
Carrier Return
Latch Arm
4.
Carrier Return
Clutch Latch
~'---- Carrier Return Lever
.030" To
\
\
rJJj""
(L \
.040" ~
" /
--
FIGURE 145. Clutch Latch Overthrow
Adjustment (723 And 725)
Carrier Return Shoe - Adjust the carrier return actuating
arm brocket left or right so that the carrier return shoe
overlaps the last 3 coi Is on the right hand end of the
clutch spring. Covering the last 3 coils insures that all
the coils of the spring will be used in the clutch opera-
tion(Fig.l46).
Carrier Return Actuating
Arm Bracket
Lost 3 c'oi Is
FIGURE 146. Carrier Return Shoe