IBM Selectric - Page 48

4.
Clutch Latch Overthrow (723 and 725) - Use the fo IIow-
ing procedure to obtain the correct clutch latch over-
throw and operational latch height on this early style
mechanism:
a.
b.
Carrier Return Lever - Position the carrier return
lever laterally on the iatch actuating arm pin so
that the carrier return latch wi II hang vertical with-
out binding against its interposer. Be sure to tighten
the Bristol screw in the lever onto the flat portion
of the pin.
Carrier Return Latch Arm Ad justing Screw (overthrow)
With the carrier return cam on the high point adjust
the latch arm adjusting screw (Fig. 133) so that the
clutch latch will overthrow the latching surface of
the keeper by .030
11
to .040
11
. Be sure that the
platen and feed rolls are installed and the index
selector lever is in the double index position when
checking this adjustment.
Adjusting Screw
Carrier Return
...... --- Latch Arm
Lever
Carrier Return
Latch Actuating
Arm
FIGURE 133. Clutch Latch Overthrow
Adjustment (723 And 725)
c. Carrier Return Latch Actuating Arm Adjusting Screw
(latch height) - With the carrier return cam latched
in the rest position, adjust the screw so that the
carrier return latch wi II pass under the cam follower
by .00111 to .010
11
(Fig. 134).
Carri er Return Latch
\
Carrier Return Latch
\ .001"
To .010"
n
Cam Follower
--- ---
FIGURE 134. Carrier Return Latch Height
(723 And 725)
47
5.
CAUTION: Any change in the carrier return latch
height directly affects the front to rear position of
the latch (with respect to the cam follower) when
the machine is at rest. See adjustment #4 in the
Operational Control section.
NOTE: On a limited number of Model 725
1
s
equipped with the early style carrier return mecha-
nism, a carrier return latch actuating arm was used
that did not have a flat surface machined on the
left end of its pivot pin. These early production
latchactuatingarmsshouldbe replaced, using Code
32, before attempting to make the carrier return
adjustments. The flat surface machined on the left
end of the pin is required to establish the proper
radial position of the carrier return lever on the pin
(with respect to the latch actuating arm), and in-
sures that the carrier return lever cannot sl i p on the
pin.
Carrier Return Shoe - Ad just the carrier return actuati ng
arm bracket left or right so that the carrier return shoe
overlaps the last 3 coils on the right hand end of the
clutch spring. Covering the last 3 coils insures that all
the coils of the spring will be used in the clutch opera-
tion (Fig. 135).
Carri er Return
Actuating Arm Bracket
Shoe Overlaps
Last Three Coi Is
6.
Clutch Spring
FIGURE 135. Carrier Return Shoe
Carrier Return Clutch Arm - Adjust the clutch arm on
the carrier return clutch arm hub so that the formed lug
which mounts the actuating arm stud will be horizontal
when the machine is at rest (Fig. 136).
7. Shoe Clearance - The nylon shoe on the clutch actuating
arm should clear the carrier return clutch spring by .015"
to .020" when the mach i ne is at rest (Fi g. 136). Ad just
the nut on the actuating arm stud to obtain the proper
clearance.
NOTE: In no case should the shoe to clutch spring
clearance be less than .015".