Wheel history

The wheel is probably the most important mechanical invention of all time. Nearly every machine built since the beginning of the Industrial Revolution involves a single, basic principle embodied in one of mankind�s truly significant inventions. It�s hard to imagine any mechanized system that would be possible without the wheel or the idea of a symmetrical component moving in a circular motion on an axis. From tiny watch gears to automobiles, jet engines and computer disk drives, the principle is the same. One can really fail trying to find a discovery that would give more powerful impulse for technological progress. Vehicle, jigger, windmill, water lift, pulley � this is far incomplete list of devices based on wheel principle. Clay tablets from Shumer �cuineinform� us of these devices of 6 thousand years old. Invention of the wheel in Sumer allowed a great increase in the trading of food surpluses and other produce and resources. A donkey can haul several times the load on a wheeled cart than it can upon its back or by pulling a loaded sled. The main problem with this method of transportation was that many rollers were required, and care was required to insure that the rollers stayed true to their course. One theory as to how this obstacle was overcome suggests a platform, or sledge, was built with cross-bars fitted to the underside, thereby preventing the rollers from slipping out from under the load. Two rollers would be utilized, with two cross-bars for each roller, one fore and the other aft of the roller. Another theory involves simply putting pins down through the corners of the sledge, utilizing two pins on the end of each roller, to hold the rollers in place. The latter theory provides a logical transition to the grooved roller, by the simple fact that friction caused by the underside of the sledge on the rollers would wear grooves in the rollers over time. In response to this, the roller may have been made thinner in the middle, and larger ends. At this point in the evolution of the wheel, we begin to see distinct, solid wheels connected by an axle-tree replacing the primitive roller. As with the simple roller, there was a significant flaw in the design of the axle-tree and solid wheel configuration. When a cart with wheels of this design is towed, cornering is an awkward, sometimes dangerous maneuver. In a sharp turn, the inside wheels are dragged around the turn, with the potential of overturning the sledge. One solution to this issue was found in the fixed axle, with wheels that rotated freely around the axle. Arranged as such, the wheels were free to rotate independently when cornering, allowing the inside wheel to turn more slowly while the outside wheel sped up. This leap forward in technology necessitated alteration of the wheel itself as well. Solid wheels were developed, with a hole bored through the center for the axle.
Based on diagrams on ancient clay tablets, the earliest known use of this essential invention was a potter�s wheel, or jigger, that was used at Ur in Mesopotamia (part of modern day Iraq} as early as 4000 BC. The first use of the wheel for transportation was probably on Mesopotamian chariots in 3200 BC. It is interesting to note that wheels may have had industrial or manufacturing applications before they were used on vehicles. First wheels were hard to move until a hub was invented. Further development gave us a light construction consisting of hub, spokes and rim. A wheel with spokes first appeared on Egyptian chariots around 2000 BC, and wheels seem to have developed in Europe by 1400 BC without any influence from the Middle East. Because the idea of the wheel appears so simple, it�s easy to assume that the wheel would have simply "happened" in every culture when it reached a particular level of sophistication. However, this is not the case. The great Inca, Aztec and Maya civilizations reached an extremely high level of development, yet they never used the wheel. In fact, there is no evidence that the use of the wheel existed among native people anywhere in the Western Hemisphere until well after contact with Europeans. As the need to move faster, and with greater ease drove man further from his home, for hunting and conquering purposes, wheels became lighter. Another reason wheels became lighter, was scarcity of materials. In order to make wheels lighter, and use less material, spokes became narrower, as did the rims of the wheel. The felloes were slimmed down by carving both sides to shape, eliminating a considerable amount of wood from the wheel, as seen in the Egyptian chariot wheel. This wheel, while lighter and faster, bore the disadvantage of requiring a skilled wheelwright to build it. The Greeks are credited with introducing the cross-bar, or H-type, wheel as an efficient, easily built wheel. The well to do used the spoked wheel, and the common, less wealthy population used the cheaper cross-bar wheel.
No one knows for sure who is ultimately responsible for the invention of the wheel although theories and speculation abound. Unfortunately, the name of inventor is unknown. But whoever he was, he was a real inventor, because the wheel does not have analogs in nature, like almost all human inventions do. For those who are religious the wheel is a true evidence of God, his gift to humanity. Now, thinking of 6000 anniversary of the wheel, we can say that the name of this inventor was Homo Sapience. Literally.

Viktor Kolesnikov


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