IBM 80 User Manual

20
CARD SO RTING MACHINE, TYPE 8-=2 _________ _
Figure 19. Feed RoIls
are friction driven from the rubber rolls above them.
This arrangement
is necessary at the second lower posi-
tion because the
size and location of the contact roll
prohibits the
use of a regular size lower feed roll. The
first and third lower
feed rolls are driven by 18-tooth
worm gears meshed with the drive shaft. All other
lower feed rolls, with the exception of the auxiliary
feed rolls, are driven by 19-tooth gears.
Downward pressure
is applied to each upper feed
roll
by means of flat tension springs on each feed roll
shaft bearing.
One exception to this, however, is the
first upper feed roll which employs 2 small spring
loaded plungers
to furnish the downward tension neces-
sary for gripping the card firmly. These small plungers
are recessed upwards into the front and rear magazine
frames. Note that the flat tension springs for the second
upper feed roll are shorter than those for the other feed
rolls. All feed rolls, with the exception of the auxiliary
rolls, run in removable porous bronze bearings set in the
side frames of the machine.
As stated above, some feed rolls are driven from 18-
tooth gears while others are driven from 19-tooth gears.
From this, it will be apparent that the shafts with 18-
tooth gears will turn faster than those with 19-tooth
gears. Therefore, it
is necessary that those feed rolls
having 19-tooth gears be enough larger in diameter
than the two having 18-tooth gears to make the peri-
pheral speeds of all rolls the same.
The first and third lower feed rolls, which are driven
by 18-tooth gears, make one complete revolution per
card
cycle. It is necessary that these two shafts make
one revolution per cycle because the commutator
is
mounted on the first shaft and the armature knock-off
screw
is mounted on the third shaft. The commutator
and the armature knockoff must stay in synchronism
with the movement of the card at all times.
All other geared rolls are driven
by 19-tooth gears
and make
18/19 of one revolution per card cycle.
This distributes the cutting effect of the cards on the
feed rolls since the leading edge of the card does not
strike the same spot on the feed rolls each cycle. The
contact roll
is also driven by a 19-tooth gear. This aids

IBM 80 Specifications

General

Brand	IBM
Model	80
Category	Office Equipment
Language	English