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aRI _ _ _ _ _
~_:!'
Steel Stop
~~~,-~
Eccentric Shaft
Screw
Cam
Fulcrum
Figure 15. Cam and Type Bar Operation
to continue its motion toward the front of the machine. Con-
tinued motion of the cam lever causes the nylon shoe on the
cam to leave the power roll and the cam spring restores the
cam to its rest position against the cam lever. The moving
type bar contacts'the ring, then whips or bends, abave the ring
so the type head may complete its travel into the type guide.
The type face strikes the ribbon and makes its impression on the
paper. The striking force or impression of each type bar is
determined by how long the cam is allowed to rotate against
the power roll before it reaches the knockout finger. The long-
Cam Lever Fulcrum
Figure 16. Cam Knockoff Point
6
er the cam remains engaged with the power roll, the longer
the type bar wi II be powered and the greater will be its strik-
ing force.
After the type bar strikes the platen, the type bar and cam
lever reverse their direction. If the key lever is helddowrl,
the rear edge of the top lug on the trip lever will engage the
front edge of the lug on the key lever as the cam lever as-
sembly restores. The cam leverwill restore to its rest position,
but the trip lever wi II remain against the key lever lug unti I
the key lever is allowed to restore. The restoration of the
key lever allows the trip lever spring to restore the trip lever
up toward the rear of the machine. This actioD of the trip,
lever insures a single operation of the cam and allowsthe type
bar to restore to the rest position, regardless of how long the
operator ho Ids the key button depressed.
When the type bar r-.eturns to rest, it strikes a spring loaded;
rubber type rest pad, which is suspended between two frames
on the segment support (Fig. 11). The type rest reduces type
bar rebounding away from the rest position and reduces
nois~.
This enables th'e type bar to be ready immediately for another
operation.
The impression of the type bars can be controlled by two
methods.
An
impression control screw isprovided below each
knockout finger to give individual .adjustment for this impres:"
sion of each typebar (Fig. 10). An impression control indi-
cator is avai lable to the operator, to provide a means of regu-
latingthe height of the knockout bar assembly (Fig. 10). This
adjusts the knockout point of the cams as a group. Moving
the impression control indicator rotates the ec,centric shaft
below the cam knockout bar assembly. Raising the bar de-
creases the impression of all type bars, and lowering the bar
increases the impression of all type bars. A reference scale,
graduated from 0 to 10, is on the impression control indicator.
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