The Washington herald., 1919-11-30

clutch which delivers II to shaft
which Is part of the transmission
unit. On this shaft are a certain num-
ber of gears which may be shifted
into and out of engagement with
other gears, mounted on another
shaft. known technically as counter
shaft These gears on the counter
shaft have varying numbers of teeth.
a condition which produces the
change in tractive effort.
The mechanical unit that we have
Just described Is known as the sliding
selective gearset and while II serves
its purpose fairly well 1t uses a tre-
mendous expenditure of effort to ac-
complish what Is comparatively a
small effect. We need a device which
shall perform this service in a simpler
and easier way. without the constant
exists with the present type.
Others Being Used.
While the sliding selective gearset
Is the prominent type today. there
are other forms In use. The next most
important Is the planetary gearset.
which is used in the Ford car which.
in point of mere numbers. makes the
type important. The planetary gear
set consists of a group of spur
gears, always in mesh with a central
IT master gear. This master gear
IS known as the sun gear and the
Spur gears as planetary gears, from
q resemblance OF the set to the oper-
atoms OF the solar system. In oper-
alton the gears are forced to re-
volve on each other. this action be-
ing induced by stopping the move
- arta hn
gears. which is accomplished by
means of a sort of brake. When the
;carset Is in high il revolves as a
unit, giving a remarkably efficient
action. One Of the drawbacks to the
planetary gearset is the fact that 1t
can only be constructed for two
speeds. as the adding of other speeds
adds SO much complication that en-
gineers are loath to employ the type.
The Ford car. ii is scarcely neces-
sary to remind the reader. has but
two forward speeds. Still when 1t is
well constructed the planetary gear
set serves its end with a reasonable
degree of efficiency.
In the truck field we find a third
type of gearset. known as the con-
slant mesh type. This variety of
transmission has not come into the
passenger car field as yet and so is
of no interest to us for the present
consideration.
Friction Set Not Used.
1t Is rather a remarkable fact
that the simplest and theoretically
the most efficient type of gearset.
the friction set. has passed out Of
use in the automobile field. The
friction gearset consists of two
discs-one driving. the other driven.
In operation the driven disc is
brought into contact with the driv-
ing disc. the rate of speed being
determined by it's distance from the
center of the driving member.
Obviously this arrangement gave
an almost unlimited number Of
speeds, smoothness of action. but
the great trouble was that the sets
did not stand up under the strains
of heavy work. At one time it en-
joyed great popularity. but it grad
ually was abandoned for heavy
work and finally even the lightest
cars gave it up in favor of the
sliding sesective type. 1t is re-
grettable that the friction set could
not stand up under tire needs of
service. for it had all the theoreti-
cal virtues that delight the heart Of
the engineer.
II the car owner will stop for just
one moment and consider the es-
sential construction of the conven-
tional gearset he will realize the need
for great care in operation and main
tenance. Two shafts holding sets of
gears. which must be brought into
engagement while the parts are spin
ming at a high rate of speed, points
to ever present danger of breakage
or injury. And this is actually so.
Breakage of members in the gearset,
bending of the shafts so that they are
out of alignment, are common in gear
set operation. When the shafts once
get out of line there is no hope Of
decent operation until the condition is
remedied, the gears will clash and
growI. the teeth will chip or suffer
more serious breaks and replacement
of gears will do no earthly good until
the entire transmission is properly
lined up again. When the shafts are
out of line the gears do not engage
evenly. as they are intended to do,
which is the whole secret of the
trouble.
OIL Best for fabrication.
The first thing to 40 to keep the
gearset up to proper operation pitch
is to give it proper fabrication. Oil
is the proper lubricant for this unit
not grease. In winter it will be well
to use a somewhat thinner oil than
in hot weather, as the cold tends to
thicken the oil anyway. Every two
or three months. or better. every
thousand miles of running. the oil
should be drained off from the gear
set housing, which should be flushed
out with kerosene and then refilled
with fresh oil. Neglect of this pre-
caution will probably bring prema-
ture failure of the unit.
Finally let us call attention to the
fact that without a gearset operat-
ing efficiently the entire operation
of the car is thrown out of gear
Understanding that the car owner
should give the part the most scrup.
ulous care that he is capable of sup
plying. Systematic care will keer
this unit moving efficiently for q
! long time, and this care is easier tc
| give than the time and trouble nee
Y