IBM Selectric Maintenance Manual page 34

4. Slowly hand cycle the machine until the check
pawl just drops into a tooth on the check rat-
chet. The print shaft gear should have rotated
1/2
to one tooth. If the print shaft gear rotat-
ed further than one tooth the collar must be
moved top toward the rear. Less than
1/2
to
one tooth, move it top toward the front.
A zero ti It, negative-f ive rotate character is used
because it offers the greatest resistance to the cycle
shaft during the restoring portion of a cycle, caus-
ing the cycle clutch spring to slip at the earliest
possible time. .
NOTE: If the collar shouid become completely
loose, a good starting point may be obtained by
positioning the collar so that its adjusting screw head
is approximately in line with the high point of the
negative-five cam.
CAUTION: The cycle clutch stop attached to the
collar may prevent the shaft from reaching the
latched position. Any change in the cycle clutch
collar adjustment wi II necessitate a readjustment of
the stop; the refore it is usually best to loosen the
stop before attempti ng to adjust the collar.
B. Degree Wheel Method
With the machine at zero degrees (cycle clutch
latched at rest) select,a -5 rotate, 0 tilt character
and hand cycle the machine slowly. The cycle
clutch spring should slip and stop driving at 170 to
175 degrees.
3.1 Cycle Clutch Spring and Collar Adjustment (Late Style
Clutch) (Fig. 43.1)
a. The cycle clutch spring and collar shall be posi-
tioned laterally to the left so that the longest
spring ear is against the minus
5
cam. The perts
are so designed that the clearance between the
cycle clutch sleeve and the pulley will be .006"
to .020".
b. Radial position of the collar - (The position of the
collar directly controls the radial position of the
left hand end of the cycle clutch spring with respect
to the cycle shaft. It determines how much the
spring clutch wi II be expanded when the cycle
clutch sleeve is latched and the cycle shaft is in
its rest position.) Adjust the collar so that when
a zero tilt, negative-five rotate character is hand
cycled the cycle clutch spring will begin to slip
(expend) when the cyc I e shaft i' S
1/16"
to
3/32"
from its rest position measured on the surface of
check ratchet (Fig.
43.1).
This adjustment is difficult to observe at the check
ratchet. A
1/16"
to
3/32"
rotation of the cycle
shaft wi II cause the print shaft gear to turn ap-
proximately one tooth. The adjustment can easi Iy
be read by one of the following methods.
2-12
1/16"
to
1 /32 "
Cycle Clutch
Check Ratchet
FIGURE 43.1 Cycle Clutch Spring And Collar Adjustment
(a) Print Shaft Gear Method
1.
Hand cycle a zero tilt, negative-five char-
acter until the cycle clutch begins to slip.
2.
Pencil mark the print shaft bearing in line
with a tooth on the gear.
3.
Release the cycle clutch again by depressing
a keybutton.
4.
Slowly hand cycle the machine until the check
pewl just drops into a tooth on the check rat-
chet. The print shaft gear should have rotat-
ed 1/2 to one tooth. If the print shaft gear
rotated further than one tooth the collar must
be moved top toward the rear. Less than 1/2
to one tooth, move it top toward the front.
A zero ti It, negative-five rotate character is used
because it offers the greatest resistance to the cycle
shaft during the restoring portion of a cycle, caus-
ing the cycle clutch spring to slip at the earl iest
possible time.
NOTE: If the collar should become completely
loose, a good starting point may be obtained by
positioning the collar so that its adjusting screw
head is approximately in line with the high point
of the negative-five cam.
CAUTION: The cycle clutch stop attached to the
collar m9Y prevent the shaft from reaching the .
latched position. Any change in the cycle clutch
collar adjustment wi II necessitate a readjustment
of the stop; therefore it is usually best to loosen
the stop before attempting to adjust the collar.