IBM Selectric - Page 19

3.
The adjustment can easi Iy be checked by hand cycl ing a
zero-ti It charactertwice in succession. As the cycle shaft
begins to pass its rest position, place your finger lightly
against the cycle clutch check pawl while observing the
selector latches. If the adjustment is correct you should
feel the check pawl drop into the rest position notch on
the check ratchet simultaneously as the two selector
latches reset under the latch bai I.
Form the stop lugs by tapping them up or down with a
hammer and screwdriver. The stop lugs should be over-
formed sl i ghtl y then brought back to the correct position,
otherwise the "memory" of the metal wi II cause them to
restore toward their original position.
NOTE: It is very important for each selector latch to
receive the same amount of motion from the latch bail,
when operated, inorder to produce the proper amount of
motion to the tilt arm link for a desired selection. If
one of the stop I ugs is ad justed too low, its respective
latch will reset early under the latch bail producing an
excessive amount of latch clearance for that latch. This
means that this latch when operated wi II not receive as
much motion from the latch bai I as the other latch wi II
when it isoperated. This condition which is undesirable
causes the band width of the system to increase.
Tilt Arm Motion - Adjustthe tilt link up or down on the
ti It arm (Figure 48) to control the ti It ring motion so that
thetiltringwillcoarsealignthesamefor a 3-tilt charac-
ter as it does for a zero-ti It character.
In orderto check this adjustment, it is necessary to roughly
home the tilt ring first. To rough home, half-cycle a
zero-ti It character and adjust the right hand ti It pulley
(Figure 48) so that the tilt detent will enter slightly on
the rear side ofthe V -shaped detent notch in the ti It ring
when the ti It ring play is removed in the restoring direc-
tion{Fig.49). Asthetiltdetentisallowed to seat itself,
the rear of the tilt ring should rise sl ightly. This is a
preliminaryadjustment and will require refinement after
the proper tilt arm motion is obtained.
Ti It Detent
Detent Enters SI ightly
To The Rear
Ti It Ring
---....,
/,... "
/ Rear Tooth "
FIGURE 49. Rough Homing
\
\
4.
17
Once the print shaft has been prel iminari Iy timed and the
tilt ring rough homed, all of the following adjustments
that require half-cycling should be done under power so
as to include all the stresses on the system.
When the tilt arm motion is adjusted properly, a half-
cycled letter"j" (3-tilt) will coarse align the same as a
hal f-cycled letter liZ II (O-ti It). That is, both selections
will provide the same rising action to the rear of the tilt
ri ng as the detent is allowed to seat in the detent notch.
Ifthe"Z" and "j" coarse align the same, the l-tilt and
2-tiltselections will also coarse align the same because
of the leverage designed into the system.
NOTE: The right hand tilt pulley lock nut may be left
loose while making the tilt arm motion adjustment, be-
cause a slight readjustment of the pulley may be neces-
sary during the tilt arm motion adjustment.
On late level machines the tilt arm link has a horizontal
elongated mounting hole where it fastens about the
shouldered screw on the tilt arm and the tilt arm is lightly
spring loaded away from the side frame by a hairpin
spring. The ti It pulley spring is far stronger than the
hairpin spring thus holding the tilt arm against the right
hand end of the elongated mounting hole in the link.
Although this modification has no definite effect on a
ti It operation, its function is to remove any slack that
may appear in the ti It tape. An example is when an
operator changes the type head she may accidentally tilt
the head causing the tape to slacken.
Ti It Ring Hom ing -With a zero-ti It character hal f-cycled
and the tilt ring play removed in the negative direction
(restoring direction), adjust the right hand tilt pulley so
that the rear of the tilt ring will rise about .005" when
the detent is manually allowed to seat in the detent
notch (Fig. 50A).
--1 -
I . 1
\ )
'" /
./
"-- ~
A
B
Play Removed In
The Positive Direction
Play Removed In
The Negative Direction
FIGURE 50.
Tilt Detent Entry