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Upper Motor Mount
-*""--I-NIIII
Stotic Eliminator
/litl
Lower Moior Mount
Figure 4.
n
Finned
II
Motor Mounts
Ring Mounting Bracket
Figure 5. Ring Mounted Motor
Two bakelite shields, formerly used, have been eliminated on
all motors. This allows a greater flow of air through the motor
thereby reducing its operating temperature.
Drive
The positive drive mechanism consists of toothed belts and pul-
leys to transfer the rotation of the motor to the power roll (Fig.
6). speed reduction from the motor to the power roll is approxi-
mately6: 1. This reduction is accomplished by using a combi-
nation of 3 pulleys and 2 belts. A drive belt transfers the ro-
tation from the motor pulley to the large side of the inter-
mediate pulley. A belt from the small side of the intermediate
pulley, known as the driven belt, transfers the rotation of the
intermediate pulley to the power roll pulley. The power roll
pulley is aj'tached directly to the end of the power roll shaft
by two bristo set screws.
The intermediate pulley
~s
mounted to the left side frame by
means of an intermediate shaft, a retaining plate and a nut.
The retaining plate acts as a locking device for the nut. The
shaft and nut have a left-hand thread so that the rotation of
the pulley prevents loosening of the shaft.
2
Figure 6. Positive Drive Mechanism
The pitch of the machine is the number of typed characters or
spaces to the inch. Machine pitch usually is determined by
the size of the type used. Type style and size also indicate
the power. roll speed needed for best impression results. The
speed of the power roll is varied by using motor pulleys of
different diameters. The diameter of the motor pulley deter-
mines the number of teeth on the pulley, and these numbers
are molded on the pulley.
The drive belts vary in diameter to compensate for motorpul-
ley sizes. This facilitates belt adjustments on shaft mounted
motors. Strips of yel)oV( or green paint on the drive belts
indicate the small and large belts, respectively.
The following chart provides recommendations for the proper
motor pulley, drive belt and power roll speed on most ma-
chine.s of a given pitch.
Pitch
Power Roll Speed
No. of Teeth
Drive Belt
FPM
RPM
on Mtr. Pulley
12 and 14
95
242
14
Y~llow
6.2/5, 8, 9,
and 10
103
261
15
Green
;-1,1;',
The ring mounted. motor must be kept toward the rear to pre-
vent interference with the lower line'lock bell crank. It is,
therefore, necessary to use the longer green belt with all ring
mounted motors, regard less of the motor pu lIey used.
Earlier model positive ,belt drives had motor pulley combi-
nations of 13 - 15 teeth and 14 - 16 teeth. Power roll speeds
. of 95 and 103 feet per minute are the only ones currently speci-
fied, therefore a 14 - 15 tooth motor pulley has replaced two
previous pulleys.
The purpose of the power roll is to supply motion for all cam
operated mechanisms. It consists of a hollow met,af cylinder
to which a rubber tube. is glued (Fig. 7). Two end plugs,
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