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The Missing Link in Tractor Development

Author Photo
By C.F. Marley

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A 1913 patent drawing of the auto tractor. Inventor Walter Zimmerman filed an earlier patent in 1911. Patents for both designs were granted in 1917, but whether auto tractors were still being produced then remains a mystery.
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This image further defines the marvelous set of gears that made the Auto Tractor what it was. The fact that these huge gears did their work without lubrication is amazing. As cumbersome as these gears appear, they were the forerunner of gears on today’s tractors. These appear to be planetary gears: If they were not, the hub gears on the car wheels would have run the tractor in reverse.
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This view of the Auto Tractor proves it capable of pulling a 6-bottom plow. The image also shows the belt pulley used for such jobs as operating a threshing machine or sawmill. Just in front of the pulley is a second radiator, designed to provide extra water to keep the car engine cool while operating at slow speeds.

“The auto tractor consists of a steel frame
upon which the automobile is carried and to which it is firmly held
when in operation. The frame is carried on two traction wheels 6
feet in diameter. Connecting the two big wheels is a steel axle
upon which is mounted the gearing, which transmits the power from
automobile to tractor wheels.

“The belt attachment for power work is mounted
on the rear end and put in operation by means of gears controlled
by feather keys. A radiator, water supply tank, centrifugal
circulating pump and connections are supplied to ensure the cool
running of the automobile engine under all conditions.

“In order to attach the automobile to the
tractor, the car is backed up with the rear wheels straddling the
tractor frame until the saddles strike the inclined top of the
frame. The automobile is then pulled back into place with its own
power by means of ropes fastened to the hub gears which act as
winding drums.”

The Pacific Homestead, Salem, Ore., 1911.

A search for a missing link in tractor
evolution is not quite the same as the archaeologist’s search for
the missing link between the monkey and man. But the search for the
missing link between the early single-cylinder tractor and the
modern high horsepower tractor retains considerable interest for
me.

That quest caught fire when I discovered the Auto Tractor. As a
lifelong journalist who’s specialized in farming and
farmer-invented technology, I was amazed by the contraption, a
mind-boggling, Rube Goldberg-type machine. I’d never seen anything
quite like it, nor had I ever heard of it. Yet as cumbersome and
ungainly as the unit appeared, it could be something special. I was
struck by the possibility this was one of the first – if not the
first – embodiments of the modern farm tractor.

The Auto Tractor, as described in company literature, “is an
attachment for any automobile and is so designed that when attached
to the automobile, the road speed of the latter is decreased and
the pulling power increased about 14 times. This ingenious machine
attaches to any standard automobile, making it possible to plow,
disc, harrow, sow, harvest and thresh and do other work, using the
automobile engine and transmission to furnish the power, and the
Auto Tractor to convert this power, so that it is available for use
on the farm.”

Literature on the Auto Tractor placed it as entering the farm
scene in about 1911. Up to that time, farm tractors were huge,
ponderous affairs, usually powered by an engine with a single large
cylinder. Hart-Parrs and OilPulls come to mind. At the same time,
C.L. Best of California had made the move that would make him the
father of the Caterpillar, but the result was a much heavier
tractor than most farmers would want.

Other combinations of an automobile and a set of tracks existed,
but again, none of these appeared to be the forerunner of the
popular-sized tractor ultimately accepted by the American
farmer.

The Auto Tractor, on the other hand, did have ponderous drive
wheels, but the engine, drive wheels and gearing had a great deal
in common with today’s tractor. Here was the multi-cylinder
automobile engine providing up to 40 hp. Also, the Auto Tractor had
the necessary gearing to convert that horsepower to turning
traction wheels with enough ground grip to pull 6-bottom plows. The
gears were admittedly huge and non-lubricated, but they existed as
a functioning component nonetheless.

The Auto Tractor’s primary inventor and producer was Walter
Zimmerman, Earlville, Ill. Zimmerman, a true believer in his
machine, set up a manufacturing plant and production line in Niles,
Mich. According to information found at the University of Illinois
archives, the enterprise was organized in 1911. By 1915, more than
1,000 Auto Tractors had been built. Many apparently went to Oregon
orchards. Archives photos showed the units at work pulling plows,
discs, log wagons and road graders, even providing belt power for a
threshing machine.

The most complete description of the Auto Tractor’s use was in a
June 8, 1914, article in the Pacific Homestead, Salem,
Ore. The author reports operation of an Auto Tractor on a 25.6 hp
1911 Buick (averaging 2 mph) at the Veritas Orchards, Medford, Ore.
Some things never change: “The farmer today is called upon to
increase production per acre to feed the people of the earth,” the
author notes, “and his only means of doing this is to increase the
efficiency of his producing methods.”

The concept of converting an expensive, open touring car into a
dual-purpose vehicle seems doomed from the start. Inclement
weather, rain for instance, would take a toll on the car’s
interior. And anyone who’s ever farmed in mud understands
immediately that there could be no practical way to disconnect the
tractor and then use the car for pleasure.

I have been unsuccessful in my efforts to locate a surviving
Auto Tractor. This “missing link” in tractor development has
apparently eluded the collector. Perhaps the unit was a victim of
its time. The company existed in the early 1900s. Could it be that
every Auto Tractor unit produced (more than 1,000) was melted down
for World War I armaments?

C.F. Marley is a retired freelance writer and editor.
Contact him at P.O. Box 93, Nokomis, IL 62075.

Farm Collector Magazine

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