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.
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.
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.