IBM 01 Maintenance Manual page 251

MODEL Cl
CUSTOMER ENGINEERING
spool, if necessary, and stops the mechanism when
the ribbon is rewound.
Operation ( ,
The ribbon-lift mechanism and the method of trip-
ping the ribbon cam through the action of the ribbon-
lift vane remain the same as on the Model Bl.
An operating link from the ribbon cam connects to
a bell crank which in turn operates the ribbon feed-
link and upper-arm assembly (Figure 36). Rotation
of the upper arm causes the inside spring-clutch to
tighten about a hub on the plastic drive-wheel, ro-
tating the wheel and the drive shaft to which it is
connected. Gears connected to the drive shaft trans-
fer this rotation to the ribbon spools. The lateral
position of the shaft controls which gears will be en-
gaged and which ribbon spool will feed.
Ribbon reverse takes place as follows: As the left
ribbon spool empties the sensing finger engages a
notch in the spool, rotating the sensing finger cam
(Figure 37). This forces the unlatching lever to the
rear and develops a pull on the wire link connected
to the reverse-lever latch, unlatching the reverse
lever. Unlatching the reverse lever allows it to ro-
tate clockwise about its mounting and position the
Figure 37.
Ribbon Reverse, Le/l Spool Empty
40