Mainspring And Cords - IBM Selectric I/O Reference Manual

LATE STYLE
Trigger Disengages
From Torgue Bar When
Correct Pawl Clearance
Exists
EARLY STYLE
FIGURE 106. Escapement Trigger Guide Adjustment
9.
Trigger Lever Upstop - With the machine at rest and a
clearance of .007" to .010" existing between the trig-
ger and the lug on the torque bar, adjust the trigger lev-
er upstop so that it has a clearance of .001" to .005"
with the trigger lever (Fig. 107).
/
I
Trigger Upstop
" .001" To .005" t---------1_l\
/
FIGURE 107. Trigger Lever Upstop
The trigger upstop prevents the trigger lever from bounc-
ing as it returns to its rest position.
MAINSPRING AND CORDS
1. Gear Mesh - The proper gear mesh between the escape-
ment cord drum and the carrier return pinion involves
two adjustments. Both must be consi dered together.
a. Adjust the operational shaft laterally so that the
crown surfaces of the escapement cord drum gear
and the carrier return pinion are even (Fig. 108).
Crown Escapement Gear Shou Id
Surfaces Even Be Positioned For .002"
To .004" Backlash At
Bearing
2-34
~i~
Tightest Point
/-- --I
~;- ~
Carrier Return
Pinion
Adjust Operational Shaft
End Play By Shi ft Arbor
And Operational Shaft Collar
FIGURE lOS. Gear Mesh and Operational
Shaft Adjustment
The position is controlled by a collar set screwed to
the shaft and the shift clutch ratchet.
Be
sure to
maintain .002" to .004" end play in the operational
shaft.
b. The escapement cord drum gear should be adjusted
forward or back to obtain .002" to .004" backlash
at the point of tightest mesh with the carrier return
pinion.
Be
sure that no binds exist throughout the
trave
I
of the carri er •
CAUTION: The mainspring tension should be RE-
LAXED before the escapement cord drum gear
i~
loosened. The cord tension should also be relaxed
by removing the cord from the pulley on the cord
tension arm. Be sure that no end play exists in the
escapement shaft before attempting the gear mesh
adj ustment •
NOTE: No attempt should be made to adjust the
cord tension with the escapement cord drum because
the drum is set-screwed to a flat spot on the escape-
ment shaft.
2. Tab Governor Pinion -Adjust the tab governor pinion to
have .002" to .004" backlash at the point of closest
mesh wi th the escapement cord drum gear. Adj ust the
pi ni on by moving both the tab governor hub and collar
located on each si de of the pinion. The pinion should
have a mi ni mum of end play yet
stj
II rotate freel y (Fig.
109) .