Rotate Mechanism - IBM Selectric I/O Manual Of Instruction

FIGURE 21. Tilt - 1 Operation
then pulled to operate the tilt bellcrank. The same action
occurs if the left latch is pulled down by the latch bail while
the right latch is held forward. The distance the vertical link
is pulled is not the same for both latches, because the link is
not connected to the middle of the lever.
When only the right latch is being operated by the bail, the
left end of the lever is not pulled down and acts as a pivot
point. The vertical I ink is attached to the lever one-third of
the distance from the pivot point to the right latch. This causes
the I ink to be pulled down only one-third as far as the latch is
pulled by the bail. The movement of the link is sufficient to
cause the typehead to ti It a distance of one band of characters.
This places the second band from the top in the printing posi-
tion.
When only the left latch is operated, the right end of the lever
acts,JS a pivot point (Fig. 22). The vertical link is then two-
thirds ofthe distance from the pivot point to the operating latch
and is moved two-thirds as much as the latch. This movement is
sufficient to cause the typehead to ti It a distance of two bands
of characters. The third band is then in the printing position.
FIGURE 22. Ti It - 2 Operation
When both latches remain to the rear under the latch bail, both
are operated. The lever moves straight down and neither end
acts as a pivot point (Fig. 23). This causes the double vertical
link to receive the same motion as the latches, resulting in three
character bands of ti It. The fourth band is then in the printing
position.
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FIGURE 23. Tilt - 3 Operation
When operated by itself, the right tilt l.atch causes a tilt of one
character band; therefore it is referred to as the tilt-one latch.
Because the left latch causes a tilt of two character bands, it
is called the tilt-two latch. Both latches operated together
cause a tilt-three bction.
ROTATE MECHANISM
Rotate Operation
The rotate mechanism rotates the type head clockwise or coun-
terclockwise to the desired character within a tilt band.
The upper ball socket to which the typehead is attached has a
shou Ider at the bottom fitted into a hole in the ti It ring (Fig.
24A). The fit is very c lose yet permits free rotary motion of
the upper ball socket. The upper ball socket is held in place
by the tilt ring spacer. The spacer attaches directly to the
tilt ring and fits around a flange of the upper ball socket.
The tilt ring spacer is shimmed to allow rotation of the upper
ball socket yet restrict up and down play.
Upper Ball Socket
Tilt Ring Spacer
FIGURE 24A. Rotate Mechanism (Early)-Rocker Portion