Centuries before the internal combustion engine was perfected, or steam power became popular, horses, mules, cattle, dogs, goats and even sheep were pressed into service to supplement human brawn as a power source. As long as the work consisted only of moving a load or machine from here to there, all that was needed was a strong draft animal or two, along with suitable harness to connect the animal to the load, and away they went. On the other hand, converting an animal's linear movement into rotary motion was not quite so simple.
The first machine to require a rotary drive motion was the gristmill, developed in the middle east about 800 BC for grinding flour. The gristmill was stationary and could be placed next to a stream or river which furnished the driving power through a water wheel. Gristmills could also be turned by windmills, with the first recorded instance being in Rome before the time of Caesar Augustus. When sawmills became popular, they too were usually situated along a stream of water. Often a single entrepreneur would build a gristmill and a sawmill side by side, and folks from the surrounding area would carry or haul their grain and logs to him for processing.
The impetus to find a better way to change the pulling power of animals into a rotary motion capable of driving machinery actually began in earnest with the development of threshing machines. These machines, in answer to the laborious and time-consuming tasks of hand-flailing and winnowing grain, became popular in Great Britain during the 1790s, and in America by the 1820s. The early machines were operated by hand, usually with two to four men tugging and turning on cranks and levers, tedious jobs that required much muscle and sweat. In 1826 it was said of Jacob Pope's Massachusetts-built threshers that it was "harder work to turn the crank than to swing the flail." Barns were seldom close enough to a stream to allow the use of a water wheel and, while the occasional farmer might have a windmill for pumping water, it wasn't powerful or reliable enough to run a thresher.
In 1822, a man named Howe patented a thresher with a vertical cylinder driven by a tethered horse walking on a large circular platform. As the platform revolved, a belt around its circumference drove a pulley on the vertical axle of the threshing cylinder.
The endless-track treadmill had been invented in England late in the 18th century to drive textile mills, and shackled prisoners often provided the power. The first successful factory in America was Slater and Brown's Cotton Mill, opening in Pawtucket, R.I., in 1790. This factory, including the treadmill that powered the looms, is said to have been manned by children ages 4-10. So, treadmills weren't new, and while at times slaves, prisoners and children were used to run them, animals were more commonly used.
Most of the early "groundhog" threshers were powered by a horse or an ox on a treadmill, but the new, combined thresher-fanning mills being developed by the Pitts brothers (and others) required more power than the old treadmills could provide. The Pitts brothers, John and Hiram, were itinerant threshermen who made many improvements to the "groundhog" threshers of the day, including an improved treadmill patented by Hiram in 1830.
Tread powers were built in many sizes, from small versions operated by a dog, goat or sheep (for running a small machine such as a butter churn), up to four-horse models (used to power large threshing machines or sawmills). All tread powers, regardless of size, consisted of an inclined box, or pen, into which the animals were driven and tied. The floor of the pen was made up of an endless chain of cross planks, each of which was supported and connected to each other and to the drive pulley by different arrangements of chains and rollers. As the animals walked upward and forward on the sloping 'floor,' it moved to the rear and turned a belt pulley or a tumbling rod, or moved a lever which drove the machine. These tread powers could be mounted on wheels for portability, a feature popular with custom threshermen who moved from farm to farm.
The Westinghouse Company of Schenectady, N.Y., built threshing machines, steam engines, sawmills and both tread and sweep horse powers. In their 1886 catalog are listed one-, two-, three- and four-horse treadmills, which Westinghouse called "Endless Chain Powers." Priced from $145 to $385, the tread powers were said to be "... in every respect, a substantial and efficient power, and adapted to all the uses farmers require power for; such as threshing, feed cutting, wood sawing etc."
Tread powers were limited to, at most, four-horse units, and not many of these larger versions were practical. As threshing machines became larger, with feed and straw conveyors as well as the new "vibrators" (or straw walkers), more power was required and sweep horse powers were the answer. FC
Ever since his years as a boy on a farm in western Pennsylvania, Sam Moore has been interested in tractors, trucks and machinery. Now living in Ohio, he's been a collector of antique tractors, implements and related items for the past 11 years.