The Washington times., 1920-01-10

also. a broken shaft would perhaps
trail and show.
Its funny how people ride around
In cars and never know what makes
'em 20. And just because they don't
know, they get In a lot OF trouoie
they wouldn't have II they did know.
For most troubles that come In the
various links in the power-chain
show their coming by symptoms
coming events cast their shadow be-
fore you know. and all that sort OF
thing"
ksov what A Clutch Isf
.shoot. I've q car don't know any
thing about. Maybe I've got q shad-
ow coming and can't see a." said
Companion, lighting up for the two OF
them. "Shoot"
"WelI, the clutch. Know what the
clutch isf It's a hand mechanical
hand which holds the engine smart
and the drive shaft together when the
car is going and let's 80 and separates
them when the car is not goinH snd
the engine Is They make clutches
out OF two cones, one fitting inside
the other, one steel. the other leather
faced Or they make them OUT OF
alternate discs OF steel ana fabric
faced steel, half on the engine smart
half on the drive shaft and heio to-
gether by a spring. Or they make
them of plates of steel running IN oil
But however they make them. their
purpose Is the same--to engage the
engine power against Inertia OF car
gradually, and take up the shock OF
such enEagement by friction ana
heat, Instead of jerk. and to provide
a means for dissssocistinE engine ana
wheels instantly.
Then Goes Into tie Gears.
after the power gets through the
clutch II goes in the gesrs-sear set
or gear box. That IL. usually u does
Some cars have tho shaft next and the
rearset next the differentisl, but gen.
eraIly it's considered better to have
IL right back OF the clutch because
then It's all sprung weight-the
weight is carried on the spring ano
not directly over the rear axle. The
gear box has q set OF shafts ana
gears in II, one set OF which can De
moved around In different positions oy
use of the gear lever. The function
is to provide a different ratio OF en-
CINE revolution to rear wheel reVoiu-
ton, not as some people fondly sup
pose, to allow tho driver TO drive AT
different speeds, but TO provioe MN
with more power when ne neeas ~.
The faster the engine goes per mile
per hour of car-speed the more power
il develops. Consequently. IL the en-
gine Is turning over twelve times Tor
every one time the shaft turns over
the engine Is exerting twelve times
the power as 1t IL when turning once
for the shaft turning once, and
RevoIve Al One Piece.
wait a minute" interrupted COM
panion. do you mean that when
car is rolling along In high the en-
CINE makes one revolution for every
revolution of the rear wheels?"
"Certainly not" snapped Old Timer.
"But when a car is in high gear the
engine and the shaft--the drive smart
are revolving as one piece Inc
rear wheels need three, three and
half. four or four and a half revolu-
tions of the drive shaft to turn them
over once-that is a product or the
designers art and is the 'fxed ratio
arranged at the factory and un-
changeable by the driver. The after
able ratio Is that OF the gear set oy
which the driver can make MS en-
CINE make a different number OF revo-
iutlons for every one or the driVe
shaft.
after the power gets through the
gear box. 1t goes through the drive
shaft. The engine shaft Is horizontal.
The gear set shafts are horizontal.
But they are, must necessarily De- at
a slightly higher level than the CEN
ter of the rear axle. Also the engine
and gear set are sprung weight-they
90 nm and down with the spring
movement Of the body OF the car.
The rear wheels and, axles are un-
sprung weight--they go up and down
onlv with the inequalities OF the road.
1t is very easy to see that the rear
axle may rise up and fall while the
engine and gear set are coming down
and .nringing back. so a rigid shaft
IL unthinkable. There must be a
hinge in 1t. somewhere. That hinge
is the universal joint-0ften two OF