IBM Selectric Maintenance Manual page 70

Adjust Clearance For
.015" To .020"
Actuating Arm Stud
Clutch Actuating
Arm----~......;..:..:...:......,,:..:...:......:..:..:..:,;.
""'-'---
FIGURE
144.
Carrier Return Actuating
Arm Adj ustment
Clutch
Spring
NOTE: In no case should the shoe to clutch spring
clearance be less than .015".
6. Overbank Adiustment "' "
\"/ith
the
CCidei
held fully to the
left against the margin stop, a clearance of .003" to
.008"
should exist between the working surfaces of the
escapement pawl and the escapement rack tooth (Fig ...
145). Adjust the left-hand margin rock bushing to ob-
tain this condition (Fig. 146).
FIGURE 145. Escapement Pawl Check
The overbank adjustment insures that the escapement
pawl wi II enter the correct escapement rack tooth
when the carrier return clutch is unlatched at the'
left margin. The adjustment may be observed from
the top with the platen and deflector removed and
the left margin stop positioned toward the middle of
the rock. The overbank may also be adjusted by ad-
justing the
lTD
rgin rock bushing to clear the nylon
washer on the margin rack by .025" to .030" with
the carrier resting at the left margin. The right hand
margin rack eccentric should be loose when making
this adjustment (Fig. 146) so that the left margin
stop will be against the stop latch on the carrier.
The .025" to .030" compensates for the .022" float-
ing action in the escapement pawl. (The correct
adjustment for the margin rack eccentric is covered
under the Margin Control section.)
FIGURE 146. Overbank Adjustment
NOTE: Any change in overbank on machines
equipped with this early style margin rock assembly
will directly affect the clutch unlatching adjustment.
7.
Clutch Unlatching - With either style margin rock held
to its extreme left position, the carrier return latch keep-
er should clear the latch by .005" to .015" at the un-
latching point (Fig. 147). Check by manually holding
the latch at the unlatching point while the machine is
idling. Lengthen or shorten the carrier return unlatching
link to obtain this clearance.
---...
"' "
f-- \
Margin Rack
Held To The
Left
""L\
I
"::::,,:,
-/
-
Latch Held Even
With The Keeper
Corner
2-44
FIGURE 147. Clutch Unlatching Adjustment
NOTE: Should the clutch fail to properly latch (on
machines equipped with the early margin rock) after
the clutch unlatching adjustment has been completed,
check the margin rack eccentric adjustment which is
10-
~ated in the Margin Control section. The eccentric may
be
holding the rock too far to the left restricting the
margin rack motion thereby reducing the amount of bite
that the latch may take on the keeper.
8. Torque Limiter - The t.orque limiter should transmit 1 to
2 pounds pull on the carrier as the carrier is unlatching
the clutch at the left margin.
If a spring scale is available, the adjustment may be
checked by holding against the carrier with the push end
of the scale and allowing the carrier to slowly unlatch
the clutch at the left margin.