Escapement Mechanism - IBM Selectric Maintenance Manual

I/o keyboardless printer
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7.
8.
'"
The support is secured to the machine power frame by
two binding screws at each end. Elongated holes inthe
machine powerframe enables the support to be adjusted
vertically.
This adjustment serves the same purpose as
the carrier buffers on the early level machines.
Print Cam Follower Stop Screw - Adjust the cam follow-
er stop screw so that the print cam follower roller clears
the print cam by .020" when the machine is at rest (Fig.
97.2). This clearance ensures that the rocker will re-
store fully on every cycle.
,--,,--\
I
'- - - - - ___ _
FIGURE 97.2 Print Cam Follower Stop Screw
Printers With Impression Control (Stick Shift)
a.
Powered Travel - With the cycle shaft latched at
rest and the impression control lever set at position
5 and the copy control lever set at 5 (all the way
back), loosen the binding screw and move the de-
tent plate forward or backward unti I a clearance of
.250" exists between the platen and the center of
the "home" character (Fig. 97.3). This clearance
may be measured with the foot of the Hooverometer
which is approximately .250". When measuring
the adjustment, remove the tilt ring play by de-
pressing the typehead I ightly toward the front of
the machine.
Hooverometer
FIGURE 97.3 Powered Travel (Late)
Note:
Position pawl mounting stud opposite backstop.
b.
Free Flight - Set the impression control lever at 5
and the copy control lever at 4 and hand-cycle the
machine until the print cam follower is resting on
the high point of the print cam. At this point,
there should be .035" of free flight between the
platen and the center of a half-cycled "home"
character. Adjust the eccentric on the impression
2-32
control lever for this clearance (Fig. 97.4). Keep
the high part of the eccentric toward the front of
the machine.
Large Spring Hook
'mp,",,;o"
CO"''"'
lm,
""J
FIGURE 97.4 Free Flight
CAUTION:
Each of these adjustments (powered
travel and free fl ight) directly affect each other
and must be adjusted alternately until both are
correct.
ESCAPEMENT MECHANISM
].
Escapement Bracket -
a.
With the carrier to the left, adjust the escapement
bracket front to rear so that .00]" to .002" exi sts
between the raised area of the escapement bracket
and the tab torque bar. The rear surface of the es-
capement bracket should be kept parallel with the
tab torque bar (Fi g. 98).
Early
printers \Afhich do not have a
iaised
Oieo
should
be adjusted for .011" to,.0]7" between the escape-
ment bracket and tab torque bar.
o
o
Escapement Bracket
Positioned to Obtain
. Clearance
o
"r-------~O
Check Entire Length of Writing
Line For Possible Warped
.00111 - .00211
o
Torque Bar
FIGURE 98.
Escapement Bracket
b.
With the carrier to the right, form the extension on
the tab rack plate so that .00]"
to
.002" exists be-
tween the raised area of the escapement bracket and
the tab torque bar. This is the extension which sup-
ports the tab torque bar on the right si de (Fi g. 99).
Note:
This part is case hardened on early machines.
Use caution when forming. Adjustment "a" should
be rechecked if this eX,t,ension is formed.

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