It's Got Legs

In 1919, while agricultural tractor designers were deliberating over the appropriate number of wheels (one, two, three, four?) or style of crawler tracks, a Kansas City company was prepared to say "none of the above."

To farmers, the majority of whom were still using equestrian power, the proposed Iron Horse tractor would be familiar in concept yet look like nothing else on the market. The tractor could be driven between fields in a conventional manner: an internal combustion engine propelled the tractor down the road on four wheels. Once in the field the wheels were moved out of the way. The Iron Horse would then stand and propel itself and a mounted plow or other implement by means of 16 "traction legs."

This combination wheel and ungulate tractor was invented by Lou M. Gardiner of San Francisco (later Pittsburgh). He applied for a patent for his farm tractor in 1918 (No. 1,409,165 was granted on March 14, 1922). Gardiner worked for Krupp in Germany before World War I, and had seen walking tractors in Europe. He wrote that his experiments with similar machines had produced the "most powerful tractor ever known for farm work."

In discussing the new tractor Gardiner wasn't afraid of a little hyperbole: "The Iron Horse tractor will be so far superior to all other tractors and will do so many more things, and will be so economical in construction and operation, that there can be no comparison between them, but it will stand absolutely in a class by itself."

At least it could stand. With the traction legs engaged the Iron Horse moved by means of two large crankshafts onto which the legs were attached. When the engine turned the crankshaft through shafts and gears, the hooves moved in a circular pattern with the rear-most feet lifting straight out of the ground as the front feet lowered. Traveling on the Iron Horse must have been slow and undulating.

The left and right leg sections could be operated independently, allowing the tractor to make nearly 90 degree turns at the end of the row. The wheels could be put back into service to get the Iron Horse out of a tough spot — deep, muddy fields would certainly have posed a challenge — or used in addition to the legs. The legs could be angled to facilitate work on hills, providing traction or leveling the tractor frame as it descended or ascended.

A manager of the would-be dealer's parts department would have been happy to discover that the tractor's 16 hooves could be replaced when they wore out or exchanged depending on conditions. Gardiner recommended a "sharp coal chisel" foot to penetrate the soil and break up the subsurface, or a foot "like that of a horse may be used on hard ground and in mowing grass or harvesting grain."

Send money now

The Iron Horse Tractor Co. produced a comprehensive catalog that reads more like a business plan seeking investors in the new company than a sales tool for a new tractor. Perhaps that's all it was. Companies were appearing and disappearing rapidly during this time. Separating con men from serious tractor builders was tough.

But the Iron Horse Tractor Co. was a sound investment, the reader was assured. Of the more than 6 million farms in the United States, most were still using horses. "There are very few of these owners of farms that would not buy a tractor if he could get one that could do all of the things on the farm, in the way of farm work, that the horse could do, and was efficient and reasonable in price, as well as durable," the catalog promised. The Iron Horse was the one that would get them to convert.

Iron Horse did not walk alone

Letters from mechanical engineers and bankers endorsing the Iron Horse seem to indicate a prototype had been built. Most likely it never moved beyond that stage.

That's not to say Gardiner's crazy machine is the only one with a footprint in the history of mobile off-highway equipment. Around this time there were a number of inventors who were trying to solve the challenges of poor road conditions and tough work environments by introducing walking machines; the Official Gazette is peppered with patents for them.