"Aarrk! Go slower! Go
slower!" the big green parrot croaked.
Professor Donaldson, who
knew a lot about literature but very little about cars, glanced angrily at
the bird as it sat solemnly swaying in his cage in the back of his
automobile.
"You've said that so often
even the bird is imitating you, Matilda," he protested to his wife.
At that moment the car
rounded a curve and Donaldson smiled in anticipation as they approached the
top of a long down grade.
"Here is a chance to try out
free-wheeling," he whispered to himself as he threw the gear lever into
neutral, took, his foot off the clutch pedal and settled back to enjoy the
smooth floating sensation. He did not notice that the motor
accidentally stalled owing to an exceptionally close idling adjustment.
The car attained sufficient
speed to coast to considerable distance along the level stretch at the foot
of the hill and then as it slowed down, the professor attempted to shift
into gear. There was a terrific clashing, but the gears would
not mesh. He pressed the clutch pedal clear down to the floor boards
and tried again with no better result.
By this time Professor
Donaldson was so flustered that he did not notice that he was coasting into
the rear of a car ahead that had stepped at a traffic light.
There was a clang, followed by a
squawk from the parrot, a shriek from Matilda, and a grunt from the
professor, who had been forcibly propelled against the steering wheel.
A grizzled head poked out of
the window on the driver's side of the car the professor had bumped and
dapper little chap with large glasses popped out of the other side.
"Nothing busted, Gus," the
latter reported after inspecting the damage. "Our car's all right.
This boob's bumper's fell off, that's all."
"I'd better take a look,"
the other grumbled as he, too, got out and looked things over.
"You can't run with your
bumper that way, mister," he observed to the professor who had not yet
recovered his breath,
"Want us to fix it for you?"
Professor Donaldson looked
at him wonderingly. "Most amazing!" he exclaimed. "I ran into
you and you offer to fix my car for me!"
"Nothing generous about it,"
said Gus. "You're going to pay for the work if you want us to do it.
My name's
Wilson. This is my partner, Joe
Clark. We run the Model Garage in the next town."
"Excellent!" said the
professor, beaming. "Fasten it temporarily and I'll follow you to your
shop."
"Well, mister," said Gus as
the two cars drew up in front of the Model Garage a little later, "I'm kind
of curious to know how you happened to slam into us that way in broad
daylight."
The professor grinned
sheepishly. "I was attempting to free-wheel down that hill and I was
unable to operate the gear lever when we reached the bottom."
"Free-wheel?" repeated Gus
in puzzlement. "Oh, I see. You were coasting in neutral, and the
motor stalled. That's why you couldn't get into gear again.
That's coasting, not free-wheeling."
"Isn't it?" exclaimed the
professor. "I thought free-wheeling was merely disengaging the gears
so the wheels could turn freely. I'm afraid I fail to grasp the
meaning of many of the terms used to describe transmission features.
What, for example does 'synchromesh' mean? Or 'silent second?'
Could you explain what those terms actually mean in ordinary language?"
"I can try," Gus smiled as
he squinted along the bumper to see if he had succeeded in removing the
kink.
"Did you ever ride a
bike, one with a coaster brake?" the veteran auto mechanic asked.
"I should say so!" replied
Donaldson. "But what has that to do with free-wheeling?"
"A whole lot," Gus stated.
"Free-wheeling is really going back to the old bicycle days. Your legs
could make the wheel go round but when you got tired pedaling or you wanted
to coast down a hill you just stopped your feet. As quick as a wink
the mechanism in the rear wheel disconnected the back sprocket so the motion
of the wheel couldn't make your feet go round.
"Free-wheeling reeling
really is as old as the hills," Gus continued. "A free-wheeling auto
is just like any other auto with one extra gadget added. That gadget
is a one-way clutch, not a whole lot different from the coaster brakes
they've been fitting to bikes for thirty years or more. And a one-way
clutch, which is what a coaster brake really is, has been used in various
machine applications for a great many more years than that.
"The winding stem of your
watch, for instance, is one of the oldest types. It uses a ratchet
that slips over the teeth one way for the free motion and hooks into them to
wind the spring when you turn it the other way. The film-winding key
on a camera has the same kind of mechanism to prevent the key from turning
the wrong way.
"The trouble with the
ratchet arrangement is that it is noisy and has a lot of lost motion, so the
really good one-way clutches have a number of balls or rollers so fitted
that they jam and lock the shafts when the force is in one direction and
start to slide when the force is applied from the other end."
"That seems clear enough,"
Donaldson observed. "But if the idea is so old why hasn't some one
used it before?"
"How should I know?"
Gus countered. "There's hundreds of ideas that might be used in a car.
Only time will tell which ones will prove worth while. Free-wheeling
certainly should save gas and wear on the motor in average driving, but sure
as shooting it's going to wear out the brake linings faster.
You'd get the most benefit out of free-wheeling in rolling country same as
you would out of a coaster brake on a bicycle. On steady, level going
it wouldn't mean anything. The cars that have it are fixed so you can lock
the free-wheel gadget and not use it while the going isn't the kind where
free-wheeling is worth while - coming down a mountain for instance, when you
want to use the drag of the motor to save the brakes."
"Now I see why my idea of
free-wheeling was wide of the mark," Donaldson nodded. "Coasting in neutral
isn't the same, is it?"
"Not by a long shot," said
Gus emphatically. "Besides, coasting in neutral is against the law in some
states because too many people got into trouble that way. They
couldn't get back into gear and got rattled same as you did. You
forgot that gears have to be turning over at somewhere near the same speed
before you can mesh 'em. Of course if you had a synchromesh transmission you
couldn't have had that trouble."
"How would that have
helped?"
"Simply because the
synchromesh transmission," Gus explained, "has an extra little clutch for
each speed that goes into action when you move the gear lever. The clutch
takes hold just before the gears go together and force 'em to run at the
same speed. Clashing gears isn't possible because clashing means
gear teeth grating past each other and when two gears are turning at the
same speed their teeth can't pass each other."
"I hope Mrs. Donaldson
doesn't become familiar with the fact that gears should not be clashed," the
professor observed, "at least until I can shift with less noise otherwise I
should be compelled, in self-defense, to purchase a car with that feature.
Is a transmission with a silent second speed constructed in the same
manner?"
"No," said Gus, "that's
something else again. Transmissions with silent second speeds really
are offshoots of another kind of development. Maybe you remember there
was a lot of talk about four-speed transmissions a couple of years ago? The
silent second speed transmission really is a relative of the fancy
four-speed outfit.
"Four-speed transmissions
were made just like the regular three-speed outfit only with an extra gear
for economical level driving. The extra fourth speed had internal
gears, which are not so noisy because the teeth kind of slide together
instead of bumping. The idea worked grand. Fourth speed was
almost as quiet as third. Then along came some engineers and said:
'why not use those nice, quiet internal fourth-speed gears for second speed
in a regular three speed job? Then people wouldn't mind using second
speed and we could gear up the rear axle a bit to get more economy'."
"H'mm" said Professor
Donaldson, "I imagine what I require is a transmission that includes them
all."
Gus grinned.
"That's an order I'm afraid no car manufacturer can fill - just yet."
END
