Neil Alden Armstrong


Download 446 b.
bet32/106
Sana03.09.2017
Hajmi446 b.
#14928
1   ...   28   29   30   31   32   33   34   35   ...   106

When viewed across the span of the 20th century, the effect that mechanization has had on farm productivity—and on society itself—is profound. At the end of the 19th century it took, for example, 35 to 40 hours of planting and harvesting labor to produce 100 bushels of corn. A hundred years later producing the same amount of corn took only 2 hours and 45 minutes—and the farmers could ride in air-conditioned comfort, listening to music while they worked. And as fewer and fewer workers were needed on farms, much of the developed world has experienced a sea-change shift from rural to metropolitan living. Throughout most of its long history, agriculture—particularly the growing of crops—was a matter of human sweat and draft animal labor. Oxen, horses, and mules pulled plows to prepare the soil for seed and hauled wagons filled with the harvest—up to 20 percent of which went to feed the animals themselves. The rest of the chores required backbreaking manual labor: planting the seed; tilling, or cultivating, to keep down weeds; and ultimately reaping the harvest, itself a complex and arduous task of cutting, collecting, bundling, threshing, and loading. From early on people with an inventive flair—perhaps deserving the title of the first engineers—developed tools to ease farming burdens. Still, even as late as the 19th century, farming and hard labor remained virtually synonymous, and productivity hadn't shifted much across the centuries. At the turn of the 20th century the introduction of the internal combustion engine set the stage for dramatic changes. Right at the center of that stage was the tractor. It's not just a figure of speech to say that tractors drove the mechanization revolution. Tractors pulled plows. They hauled loads and livestock. Perhaps most importantly, tractors towed and powered the new planters, cultivators, reapers, pickers, threshers, combine harvesters, mowers, and balers that farm equipment companies kept coming out with every season. These vehicles ultimately became so useful and resourceful that farmers took to calling them simply GPs, for general purpose. But they weren't always so highly regarded. Early versions, powered by bulky steam engines, were behemoths, some weighing nearly 20 tons. Lumbering along on steel wheels, they were often mired in wet and muddy fields—practically worthless. Then in 1902 a pair of engineers named Charles Hart and Charles Parr introduced a tractor powered by an internal combustion engine that ran on gasoline. It was smaller and lighter than its steam-driven predecessors, could pull plows and operate threshing machines, and ran all day on a single tank of fuel. Hart and Parr's company was the first devoted exclusively to making tractors, a term they are also credited with introducing. Previously, tractors had been known as "traction engines."

  • When viewed across the span of the 20th century, the effect that mechanization has had on farm productivity—and on society itself—is profound. At the end of the 19th century it took, for example, 35 to 40 hours of planting and harvesting labor to produce 100 bushels of corn. A hundred years later producing the same amount of corn took only 2 hours and 45 minutes—and the farmers could ride in air-conditioned comfort, listening to music while they worked. And as fewer and fewer workers were needed on farms, much of the developed world has experienced a sea-change shift from rural to metropolitan living. Throughout most of its long history, agriculture—particularly the growing of crops—was a matter of human sweat and draft animal labor. Oxen, horses, and mules pulled plows to prepare the soil for seed and hauled wagons filled with the harvest—up to 20 percent of which went to feed the animals themselves. The rest of the chores required backbreaking manual labor: planting the seed; tilling, or cultivating, to keep down weeds; and ultimately reaping the harvest, itself a complex and arduous task of cutting, collecting, bundling, threshing, and loading. From early on people with an inventive flair—perhaps deserving the title of the first engineers—developed tools to ease farming burdens. Still, even as late as the 19th century, farming and hard labor remained virtually synonymous, and productivity hadn't shifted much across the centuries. At the turn of the 20th century the introduction of the internal combustion engine set the stage for dramatic changes. Right at the center of that stage was the tractor. It's not just a figure of speech to say that tractors drove the mechanization revolution. Tractors pulled plows. They hauled loads and livestock. Perhaps most importantly, tractors towed and powered the new planters, cultivators, reapers, pickers, threshers, combine harvesters, mowers, and balers that farm equipment companies kept coming out with every season. These vehicles ultimately became so useful and resourceful that farmers took to calling them simply GPs, for general purpose. But they weren't always so highly regarded. Early versions, powered by bulky steam engines, were behemoths, some weighing nearly 20 tons. Lumbering along on steel wheels, they were often mired in wet and muddy fields—practically worthless. Then in 1902 a pair of engineers named Charles Hart and Charles Parr introduced a tractor powered by an internal combustion engine that ran on gasoline. It was smaller and lighter than its steam-driven predecessors, could pull plows and operate threshing machines, and ran all day on a single tank of fuel. Hart and Parr's company was the first devoted exclusively to making tractors, a term they are also credited with introducing. Previously, tractors had been known as "traction engines."



The Hart-Parr Model 3 tractor was a commercial success, prompting no less a businessman than Henry Ford to get into the picture. In 1917 he introduced the Fordson, weighing as little as one ton and advertised to sell for as little as $395. The Fordson soon ruled the tractor roost, accounting for 75 percent of the U.S. market share and 50 percent of the worldwide share. Nevertheless, the tractor business remained a competitive field, at least for a few decades, and competition helped foster innovations. Tractors themselves got smaller and more lightweight and were designed with a higher ground clearance, making them capable of such relatively refined tasks as hauling cultivating implements through a standing crop. Another early innovation, introduced by International Harvester in 1922, was the so-called power takeoff. This device consisted of a metal shaft that transmitted the engine power directly to a towed implement such as a reaper through a universal joint or similar mechanism; in other words, the implement "took off" power from the tractor engine. The John Deere Company followed in 1927 with a power lift that raised and lowered hitched implements at the end of each row—a time- and labor-saving breakthrough. Rubber tires designed for agricultural use came along in 1933, making it much easier for tractors to function even on the roughest, muddiest ground. And ever mindful of the power plant, engineers in the 1930s came up with diesel engines, which provided more power at a lower cost.

1   ...   28   29   30   31   32   33   34   35   ...   106




Ma'lumotlar bazasi mualliflik huquqi bilan himoyalangan ©fayllar.org 2024
ma'muriyatiga murojaat qiling