Crawlers: Gaining traction around the farm

The concept of a vehicle that carries, lays and then picks up its own tracks after passing over them has been around for centuries.

Crawlers

In 1713, Frenchman M. D’Hermand sketched a goat-pulled cart that ran on a belt-type treadmill.

Englishman Richard Edgeworth tried unsuccessfully to power a similar vehicle with steam in 1770.

In 1825, Sir George Cayley received a patent for a wagon supported on an endless chain belt around the two wheels on either side, but it had no provision for steering and it went nowhere (with no steering, maybe everywhere?).

Another Briton, John Heathcoats, built a steam plowing engine in 1832 that ran on two 7-foot wide belts.

The 30-ton machine ran on belts to keep it from sinking into marshland and got a lot of attention until it slipped into a swamp and nearly disappeared and is probably there yet.

Warren P. Miller of Marysville, California, demonstrated a tracked, steam plow at the 1858 California State Fair for which he won a cash prize, as well as a gold medal.

According to the patent drawings, Miller’s machine had most of the features used on later, successful crawlers but, for some reason, only one was ever built.

George Minnis broke sod near Ames, Iowa, with a tracked steam engine in 1869 and, in 1871, a Philadelphia man, R.C. Parvin, demonstrated a crawler-type steamer at the Illinois State Fair and started a company to build the machine, but it failed.

Much money was spent on both sides of the Atlantic to make a traction engine that could pull a heavy load in soft ground.

The intricacies of crawler tracks escaped most inventors, so they relied on wheels, and the only way they could secure traction was to increase weight, which, of course, caused the wheels to sink farther into soft ground.

Chicagoan George H. Edwards patented an unpowered traction truck in 1888, and a few years later he designed what he called a trussed agricultural tractor that was steam-powered and used an improved version of his traction truck.

A review of the Edwards machine in the March 1897 issue of The Horseless Age magazine tells us, “The object of the invention is to utilize steam power in plowing, seeding, harvesting, ditching, threshing, hauling, railroad construction, bridge building and to perform such operations on such a large scale that they will be exceedingly economical.”

The article further states that, “The first tractor built on the folding truss plan weighed fourteen tons, and although a very crude affair, is said to have demonstrated in the field the basic principles used for distributing weight. The second machine weighed twenty-four tons and proved itself capable of running over very soft ground and of pulling heavily.”

Steel

These early machines apparently followed current practices of the day and used a lot of wood for frames and other weight-bearing parts, but Edwards “concluded to build a machine entirely of steel and iron, which would weigh but ten tons and do the actual work of fifty horses.” (One has to wonder upon what data Edwards based his “fifty horses” estimate.)

Anyway, the article goes on, “An expert draughtsman was employed to aid in first putting the machine on paper. One year was spent in this work alone.”

Looking at the illustrations, I believe I could have drawn the thing in a week, but I’m certainly not an “expert draughtsman.”

The “trussed” part of the machine is puzzling, but is explained by the following, “In traveling over a field the condition of the soil practically necessitates not only the use of an endless belt for the wheels to roll upon, but also a means of so trussing or bracing the endless track between the front and rear wheels (of the track) so the weight is distributed and a large part of the track surface bears on the ground.”

Edwards claimed that his machine with a 50-hp steam engine could “plow four to five acres an hour, and in 16 hours do the work of 100 horses (?) at a cost less than one-sixth that of horses. A man and a boy can handle it on any kind of land, even when water runs in the furrow, the cost per day being $3 for labor, $6 for coal, and three or four times as much for the 3,000 pounds of water per hour (about 360 gallons) which the machine requires.”

He also said the machine could be “turned completely around in 65 feet” like that was a big advantage, but it sounds to me like some pretty wide headlands would be needed at the ends of fields.

To get around the large amount of water required for steam power, Edwards “concluded to rebuild two of his tractors and put on gasoline or oil engines having a cooling device of his own, which renders a small quantity of water sufficient to keep the cylinders from overheating.”

(Author’s note: Notice the use of the word “tractor” in the preceding paragraph that was written in 1897, long before an employee of the Hart-Parr Co. was said to have coined the name.)

If Mr. Edwards ever built his all-steel and iron tractor powered by an internal combustion engine, it didn’t become successful, because I’ve found no further mention of the contraption.

Apparently, it was just another of the thousands of ideas folks had back then when motor vehicles of all kinds were just beginning to appear.

However, all the unsuccessful designs showed what not to do, and helped to perfect the modern machines we have today.