IBM Selectric I/O Manual Of Instruction page 22

Cy.CI.
Cy. CI. Latch Link
Cy. CI. Latch
FIGURE 39. Cycle Clutch Latch Mechanism
position behind the cycle clutch keeper (Fig. 39). The cycle
clutch keeper is an adjustable plate mounted, by means of the
cycle cl utch keeper bracket, to the guide comb support under
the front of the keyboard section. An extension spring exerts·
a pull toward the front on the cycle clutch latch link. The
pawl, being attached to the I ink, prevents the I ink from being
pulled forward.
When the keylever is depressed, the interposer beneath the key-
lever forces the cycle bai I to pivot downward. The cycle bai I
moves the cycle clutch latch pawl down disengaging it from the
keeper. The extension spring at the front of the I ink is then
allowed to snap the I ink and cycle clutch latch forward disen";
gaging the latch from the clutch sleeve. This allows the cl utch
spring to tighten and begin a cycle operation.
A small lever, called the cycle bai I damper, pivots at each
side of the keyboard just above the cycle bail (Fig. 40). An
extension of each lever rests against the front of the bail. An
extension spring connected between the cycle bai I and each
damper has the dual purpose of restoring the cycle bai I upward
and holding the damper against the bai I; The purpose of the
dampers is to I ightly retard the upward movement of the cycle
bail so as to prevent the bail from bouncing as it reaches its
upward limit. Without the dampers the bail has a tendency to
bounce down and retrip the cycle clutch creating an additional
cycle.
Filter Shaft
Cycle Bail Damper
Restori ng Arm / '
FIGURE 40. Cycle Clutch Latch Restoring
Operation (Early Style)
15
Early Style Restoring Mechanism.
For a cycle operation, the cycle shaft must be limited to 180
0
rotation. This means that the cycle clutch latch must be re-
stored and held to the rear into the path of the second step on
the cycle clutch sleeve. A two-piece adjustable restoring de-
vice pivots on the cycle clutch latch bracket. As the filter
shaft rotates during a cycle operation, a blade of the filter shaft
forces the restoring follower to the rear (Fig. 40), The follower
and restoring arm actsasone piece; thus the restoring arm moves
to the rear and pushes the cycle clutch latch back into position
to stop the cycle cI utch sleeve. The latch is restored far enough
tothe "rear to permit the cycle clutch latch pawl to reset on the
cycle clutch keeper and maintain the parts in the rest position.
Late Style Restoring Mechanism
The new style cycle clutch latch restoring mechanism consists
ofacamand a cam follower. The cam, called the cycle clutch
latch restoring cam, is a double lobed nylon cam mounted on
the cycle shaft (Fig. 41). The cam follower is an extension of
the cycle clutch latch which protrudes to the rear of the ma-
chine just above the restoring cam. The extension has a small
adjustable steel roller mounted on it which riides on the cam dur-
ing a restoring operation.
When the machine is at rest the low point of the restoring cam
is directly below (but not in contact with) the steel roller
(Fig. 41). Whenakeylever is depressed the cycle clutch latch
pawl is pushed off its keeper allowing the cycle clutch latc.h to
swing forward releasing the cycle clutch sleeve. When the
cycle clutch latch swings forward the steel roller on the exten-
sion drops down onto the restoring cam. As the cam rotates
Cam Follower Restore Cam
Cycle Clutch Latch
FIGURE 41. Cycle Clutch Latch Restoring
Operation (Late Style)