- Related Articles
- LET'S TALK RUSTY IRON
- A Cut Above:
- VINTAGE IRON
Stepping It Up:
Sweep powers boosted early farm production
By Sam Moore
In the early 1800s, the drive to increase farm production put horses to work in treadmills. But soon even basic horse power was not enough.
As threshing machines became large] and more sophisticated, with feed and straw conveyors, as well as the new "vibrators" (or straw walkers), horse-powered treadmills could not keep up. Sweep powers were the immediate answer. It's unknown when the sweep power was introduced, but an 1836 illustration of a Gaar thresher shows a four-team sweep power driving a ground jack through a tumbling rod. A belt from the pulley on the ground jack drives the thresher.
A typical sweep power consisted of a heavy wooden frame that could be mounted on wheels for portability. A large, cast iron bull gear was mounted horizontally on that frame so it could rotate. On the bull gear were heavy sockets to which were attached wooden sweep arms. The teeth on the bull gear engaged small diameter pinion gears on either end of a cross shaft, in the center of which was a large spur gear. The spur gear turned a small pinion gear underneath the frame that drove the output shaft. A tumbling rod from the output shaft ran directly to the driven machine, or else it drove a pulley on a ground jack to which the machine was belted.
The driver had no reins, just a whip and his voice to control his animals. In the book "Machines of Plenty," Stewart Holbrook likened him to a circus ringmaster. Of course, his charges couldn't escape or attack him, being firmly attached to their sweeps, but it was his duty to keep the teams marching at a steady pace, no matter what the power demands of the thresher. With a mixture of cajolery, threats and imprecations, plus judicious flicks of his whip, the driver kept his animals to the task as he watched them go round and round and round...
Sweep powers were built in many sizes, ranging from one-horse up to 16-horse and, although I haven't heard of any designed for dogs, goats or humans, anything was possible.
Sweep hay presses (or balers), powered by one or two horses, differed from the threshers in that the sweep was attached directly to the driven machine. With most balers, the rotary motion of the sweep was transmitted by a toggle mechanism to drive the plunger back and forth, compressing the hay until the bale could be tied. On some balers, the sweep traveled back in a semi-circle, requiring the team to be turned at each end of the arc.
Grist mills had the sweep connected directly to one of the burrs (usually the upper) and the horse, while walking around in a circle, turned the burr and the hopper. The person feeding the mill had to be alert and step over the sweep each time it came around, although some models had a platform that turned with the burr. From an account of such a mill:"We'd hitch old Dolly to the sweep, and I'd chase her round and round as John kept pouring the grindings back into the hopper, screwing down the burrs a little finer with each pass. The scoop would be held high above the hopper to blow away all the 'cornfeathers' and bran as the grindings were poured back into the hopper, over and over again, until the coarseness was all gone."
In the days before gasoline engines and electric motors, animals turned many other machines, including sorghum mills, corn shellers, buzz saws, grind stones, water pumps, cream separators, feed cutters and maybe even washing machines.
Threshing machines, steam engines, circular saw mills, horse tread powers and horse lever (sweep) powers were all offered by the Westinghouse Company of Schenectady, N.Y. in the company's 1886 catalog.