IBM Selectric Maintenance Manual page 42

J
' - !/
-'-
/
..........
"-
I \
I 1
\ J
\.
/
A
B
Play Removed In
The Negative Direction
Play Removed In
The Positive Direction
FIGURE 67. Tilt Detent Entry
5. Rotate Spring Tension - Adjust the rotate spring in the
rocker so that it wi II have 1-7/8 to 2 pounds tension
when the machine is half-cycled using a lower case neg-
ative 5 character. The least amount of tension is pres-
ent in the spring when it is in this positi on. The typehea ...
must be removed when making this adjustment.
The rotate spring tension is adjusted by turning the spring
cage from the front (Fig. 68A). The cage can be turned
clockwise to increase the tension by pulling the cage to-
ward the left with a spring hook. The spring drum re-
tainer automatically snaps into position to retain the ad-
justment. If tension is to be decreased, the retainer
must be pulled forward to allow the cage to rotate coun-
tE!rclockwise. Care must be taken to decrease the tension
slowly so that the cage does not spin freely. Spring dam-
age could otherwise result.
Rotate Spr
Retainer Clip
FIGURE 68A. Rocker Assembly
2-19
Tension of the spring is critical in that it must be prop-
erly balanced with the springs of the wear compensator.
Excessive tension wi II overload the levers system and
increase wear. Insuffi ci ent tensi on wi
II
not provide the
torque necessary for rapi d lower case negative rotate
operations. It will also affect the wear compensator op-
eration if the tension is not sufficient to overcome the
compensator damper spring in the negative-5 position.
The rotate spring tension should be measured with a spring
scale as indicated by Fig. 68B. Using a lower case -5
character, read the spring scale while slowly allowing the
shift arm to move in towards its stop screw. The spring
scale shou Id read 1-7/8 to 2 pounds just as the arm
reaches its stop screw. To overcome static friction, read
the spring scale while the arm is moving.
Shift Arm Moves
Toward Left
FIGURE 68B. Spring Scale Measurement For
Rotate Spring Adjustment
If a spring scale is not available, the tension may be ob-
tained in the following manner (Fig. 69). With the ma-
chine half-cycled at a negative five lower case {mach-
ines which are locked in upper case use upper case -5
character} position and the typehead removed, insert a
large spring hook around the lower compensator arm.
Pull so that the rotate arm eccentric just clears the damp-
er spring and release it. The tensi on of the rotate spring
should be enough to completely collapse the damper spring
against the power frame with the damper spring stop ad-
justed at the bottom of the spr"ing.
Machine Half Cycled To
A
Negative 5 lower Case
Character
Damper Spring Must Be
Completely Collapsed
Stop Set at
Highest Position
I
Damper Spring
Not Completely
Collapsed
FIGURE 69. Rotate Spring Tension