The Washington herald. [volume] (Washington, D.C.) 1906-1939, 1920-11-28
Universal Part May Even
Cause Additional Tire
- Wear.
SECTION SPEED VARIES
Helpful Hints on Oiling En-.
CINE Given for Mo-
torist.

automobile which the most expert
enced Of us knows little about. The
universal joint Is one Of these little
things Perhaps because 1t gives
little trouble is one reason why We
know 50 little about 1t. but aside
from being about the hardest work
ing part Of the car, II Is also the
most efficient and one of the most
peculiar In its action You perhaps
didn't know that the universal joint
can affect tire wear, but that Is
true. nevertheless. under certain
conditions. Perhaps you also did
not know that the standard uni
versal Of today. the all-metal Spicer,
Is fundamentally like the original
simple Cardan joint conceived about
400 years ago. These are facts
The universal joints are those
units which are attached to the pro-
peller shaft of your car and enable
that shaft to transmit the power to
the rear axle and at the same time
move up and down and sideways,
depending on the action Of the rear
axle. The axle being on the
ground and the engine clutch and
Transmission on the frame, the con-
nection between power plant and
axle must be flexible. That Is why
they put universal joints on the pro-
peller shaft These joints allow
universal movement or movement
in any direction According to
tests made by Spicer;. these joints
will average 50 per cent efficiency,
which Is more than we can say of
many parts which have to take
practically the entire torque and
power of the engine.
Speed of Parts Varies
The strangest thing about uni
versal is that one part of 1t runs
at a constant speed and the other
varies its speed depending on the
angularity of the joint This varia-
ton in speed may be as high as 20
per cent. Ii is stated, by joint max
ers. The driving member Of the
Joint is attached to the rear Of the
transmission and this runs at fairly
constant speed, butt to the angle
which the joint makes the driven
member of IT changes its speed four
times in each revolution Now II
one part of joint runs at one speed
and another part varies the driving
system would have to Withstand
IeTTluC STRESSES. NJ"
ever, there are means of overcom-
ing the results of such action. The
straight line driving is one of them
and absolutely essential on a shaft
with only one joint, If we are to
avoid short life of parts and Excess
siye tire wear. The tires tend to
slip when a one-joint shaft makes
an appreciable angle and Is &C
CELEBRATED.
For some years past there has
been a strong tendency toward the
two-joint drive-that is, a propeller
shaft with one joint at each end
This overcomes the trouble previ-
ously mentioned, or better, 1t over
comes the effect of the trouble.
Whereas the driving member of the
forward joint runs at constant
speed the propeller shaft speed
iuctuates, but the driven member
Of the second or rear joint runs
again at constant speed. and 1t is
constant speed of the pinion shaft
(which is driven by the rear joint
which we are after.
where to Trace Trouble.
Owners of automobiles in which
two-joint shaft Is used have a drive
of great hexibility because the rear
springs take the drive and torque,
that Is, the car Is pushed forward
through the rear springs. II these
springs are not fastened in place
well they will move relative to the
axle, with the result that the uni
versal joints will have to do work
which they were not intended to do.
Many owners who experience uni
versal joint trouble can trace 1t d.
rectly to loose spring clips
In addition to the fiexibility OBJ
tanned through the bending of the
springs, this form of drive obtains
fexibility because of the use of the
slip joint One joint of the two al
ways is made with a so-called slip
Joint or sliding joint The universal
action is the same and the construc-
tion also with the exception of the
method of attachment to the shaft
This Is splined and the end of the
universal splined to receive the
shaft. One slides inside the other to
compensate for shortening of the ef-
fective shaft length when the axle
moves up and down.
Travels ms Fast ms Engine.
A universal joint travels as fast
rs the engine. 1t is q fundamental
rule in fabrication of machinery that
the part should be fabricated ac-
cording to its speed and load. A
joint moves fast and nearly always
is under heavy load. The joint
ought to be packed with grease, but
not so full that movement of the
joint and centrifugal force will
cause the grease to ooze out Of the
joint cover. It is recommended that
Q joint case be packed one-third full
- grease, at least this amount gives
the best results. according to the
Spicer company, which ought to
know. Ordinary grease Is q satis-
factory lubricant. but a mixture OF
grease and graphite gives better re-
suits Joints will require repacking
about three times a year. Most
owners never bother at all about the
because the grease re-
mains In place as long as two years
However, to be on the safe side, 1t
should be the owners duty to re-
move the Joint housing or cover.
This Is for examination and repack- |
ing. though the latter also can be |
simply by removing a |
grease plug and injecting lubricant
Nth q KreasA gun