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A beveled gear transmits power to a second
shaft which has a low speed gear with 28 teeth and
a high speed gear of 43 teeth. These two gears
supply power to the drive section of the high and
low speed clutches. With power turned on, the
gears up to this point are continuously running.
Clutches
Each of the clutches has two faces, the drive gear
and the driven gear, which have interlocking teeth.
Clutch engaging cams operate against the movable
drive face of either clutch, force the clutch teeth to-
gether, and drive the carriage mechanism at the
proper speed. An interposer inter lock prevents both
drive clutches from engaging at the same time.
The clutch magnet must be energized whether the
carriage is to space or skip. Spacing is normal ad-
vancement of the platen by a single space. Skipping
is moving the plate_n more than one space. The low
speed clutch is used for all spacing operations. The
high speed clutch is used for all skipping operations.
Interposers
Figure 2-14 shows the method used in selecting me-
chanically the correct clutch for either spacing or
skipping. To operate a clutch engaging arm, an in-
terposer must be positioned between the T lever and
the clutch engaging arm. The selection of the low
and high speed interposers is determined by the elec-
trical circuits which cause the interposer magnet to
be energized. When the interposer armature is in
the normal position, the low speed interposer will be
operated by the T lever, and the low speed clutch
will supply power to the platen. When the interposer
armature is attracted, the low speed interposer will
be moved to a position where the inter lock plate will
support it but the T lever will move in the cut away
portion of the low speed interposer. At the same
time, however, the high speed interposer has been
moved into position so that the T lever will cause
the high speed clutch engaging arm to operate
(Figure 2-14).
For normal spacing, only the clutch magnet is
energized. For all skipping operations, the normal
circuit to the clutch will be open and the interposer
magnet will be energized first. To ensure that the
interposers are correctly positioned, the circuit to
the clutch magnet cannot be completed except through
Clutch
Low Speed
Interposer
Contact Closed
·r
CT
Low~
High~
High
~
Figure 2-14. Carriage Interposer Operation
2.9
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