Spacebar - IBM Selectric I/O Manual Of Instruction

Feedback Contact
The feedback contacts are located in the right rear corner on
top of the power frame. The contact on the left is the car-
rier return-index contact and the one on the right is the tab-
spacebar-backspace contact (Fig. 128).
MAIN SPRING
TAB- SPACEBAR- BACKSPACE CONTACT(C-5)
FIGURE 128. Operational Feedback Contacts
The carrier return-index contacts are operated by a tab on
the cam follower lever. The tab-spacebar-backspace con-
tacts are operated by an auxi liary cam follower lever.
As the cam follower lever or the auxi liar}' cam follower lever
are operated, the bail moves down, closing the contacts.
The follower lever restoring allows the contact to open (Fig.
129) •
Spacebar
Auxiliary Cam Follower
Feedback Contact
Nylon Pad
FIGURE 129. Feedback Contact Operation
SPACEBAR
The spacebar mechanism provides the operator with a means
of moving the carrier to the right one space at a time with-
out typing a character on the paper. It is used mainly for
spac ing between words, but it maya Iso be used to space the
carrier quickly to any point toward the right on the writing
line.
The spacebar operates by tripping the escapement pawl and
backspace pawl out of their racks as on a print escapement
operation. The two escapement operations are identical ex-
cept for the method of actuating the escapement trigger lever.
Spacebar Lever Mechanism - Early Level
The spacebar mounts on the keyboard just in front of the
keybuttons. It is suspended on two arms extending forward
from the spacebar shaft (Fig. 130). The spacebar shaft is
shou Idered at the left end and pivots in a hole in the left
keyboard sideframe. The right side pivots on -a pivot screw
in the right keyboard sideframe. Vertical motion of the
spacebar causes the spacebar shaft to rotate.
Spacebar LeYer
FIGURE 130. Spacebar Lever Mechanism
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