Shift - IBM Selectric I/O Manual Of Instruction

Keyboard Lock Contact Assembly
A contact is transferred when the keyboard lock is operated.
This is accomplished by a tab on the bellcrank that is operated
by the keyboard lock bai I (Fig. 57A).
44 Character Keylever Lock (Early) - Figure 57B
A bracket on the left end of the key lever lock bai I operates
the keylever lock. The keyboard lock bai I pushes the link
forward. The link operates the keylock interposer which
locks the keyboard as previously described.
44 Character Interposer Lock (Late)
When the lock bai I moves forward it pulls on the link which is
connected to the interposer lock. The bottom of the interposer
lock pivots forward under the character interposers and pre-
vents depression of all character interposers.(Fig. 57A).
Shi ft Lock Re lease
A bracket on the left end of the keyboard lock bai I operates
the shift lock latch. When the bai I moves to the front, the
shift lock link moves forward. The link operates the shift lock
interposer (Fig. 59).
Shift-Lock Interposer
FIGURE 59. Shift-Lock Interposer
The shift lock interposer moves front to rear. It is supported
at both ends by a guide comb. As the link pushes the inter-
poser to the front, the interposer contacts a stud on the lock.
The lock is pushed away from the shift stop, releasing the
shift key. The machine wi II return to lower case.
. Shift Lock Release (835 Printer)
!
A magnet assembly is used to release the shift lock. The mag-
; net is mounted to a bracket on the lower left keyboard side
frame. The magnet armature extends upward and contacts a
lug on the shift-lock interposer (Fig. 59.1). When the mag-
'net is energized the armature moves forward, pulling the
shift-lock interposer forward, releasing the shift-lock latch.
•
22
~
Shift Lock
~
Sh i ft Lock Magnet
FIGURE 59.1 Shift Lock Release (835 Printer)
Cyc Ie Clutch Paw I Stop
Mounted on the lock bai I and spring loaded to operate with
the bail is the slide assembly. The slide assembly has a link
which connects to the cycle clutch pawl stop (Fig. 57A).
As the slide assembly moves forward with the lock bail the
pawl stop is positioned under an extension of the cycle clutch
pawl, and prevents the cycle clutch from being released.
SHIFT
The purpose of the shift mechanism is to rotate the type head
180
0
in the counterclockwise direction. This action places the
upper case hemisphere of the typehead near the platen for typ-
i ng upper case characters. Each upper case character is in the
same ti It band as its lower case counterpart, but 180
0
from it.
Thus, depression of a keylever with the shift in operation
causes an upper case character to print.
The shift mechanism consists of a shift arm, shift cam, spring
clutch, clutch control mechanism and interlocks. The shift
mechanism takes its power from the right end of the oper-
ational shaft. All the components are concentrated in that
area .
Shift Operation
The shift operates by moving the right hand rotate pu Iley to-
ward the right (Fig. 60). The movement of the pulley creates
sufficient pull on the rotate tape to cause 180
0
type head ro-
tation. The pulley remains in this position as long as the shift
keylever is held depressed.