|
|
A Wheel is a circular structure or disk, designed to rotate on a central axis. The
invention of the wheel has proved to be a path breaking invention paving the way for the
development of virtually all modes of ground transport and more. The applications
of the wheel in modern life and technology are virtually infinite.
Man began to make tools, and there began a revolution in the history of mankind, a
timeline worth recording. People through out the world have benefited by the invention of
wheel right from ancient times. As a matter of fact, this invention is surely one
of the most important in history. Wheel has played an active role in the
development of crucial mechanical devices ever since it emerged. The most
immediate benefit was the improved efficiency in transport. People began to travel from
their villages to other villages, exchanged grains and goods and this enhanced the
development of mankind and commerce.
|
|
A
representation of an ancient wheel |
A painting showing primitive wheels |
|
| |
|
The earliest
known wheels were constructed in Mesopotamia around 3500 to 3000 BC.
Archeologists do not know if the potter’s wheel was invented first or
the vehicle wheel. Both were originally made of wood and have decayed,
leaving no convincing evidence. The oldest evidence of the vehicle wheel
is a rough sketch of a cart on a clay tablet found in Sumeria
(Mesopotamia) dating 3500BC.
The most accepted idea
is that the wheel was developed from tree trunks and used as rollers.
But there are no ancient drawings to sustain the theory. The oldest
surviving wheels, were found in Mesopotamian tombs between 3000 to
2000 BC. These were made of three strips of wood clasped together with
cross- struts and with a natural knothole in the central plank, which
acted as the pivot. This wheel turned on a fixed axle, and the wood
around the axle was very tough and wear resistant.
|
 |
|
A Depiction Of An Ancient Wheel |
|
|
|
Wheels were initially
solid disks, but gradually evolved into the spoked design, which is both
light and strong. One of the first developments that took place in
the original designs was to add a wooden rim to the three planks, which
fabricated the wheel evenly all around. The rim was a single piece of
wood steam bent in to a circle, or several segments joined together. As
observed in the Mesopotamian wheel of 2500 BC, copper nails were studded
in order to resist wearing off and were held on a leather tire. Metal
tires came into the picture after 500 years.
Eventually sections were carved out of the disk to reduce the weight
to help in maneuverability, and radial spokes were devised about
2000BC. These were mainly used for the war chariots.
|
|
| |
Depiction of an ancient wheel showing spokes |
In the case of a fixed axle, the wheel was held in place beside the framework by a small
peg and rotated independent of the axle which differed from the moving axle, in which the
axle was firmly fixed to the wheel and the two components revolved as a unit. Roller
bearings were developed around 100 BC, which helped the wheels to run more smoothly.
There were a lot of minor changes, until the invention of the Wire Wheel, which was
created for the bicycle in the 1870s. Pneumatic tire was introduced in late
1880’s. The earliest cars had wooden spoked wheels, wire wheels or artillery wheels.
The Pressed Steel Wheel replaced these in 1930s, the advantages being that it was
lighter, stronger and cheaper to produce.
These days cast wheels have reappeared in the market, are used for sports cars, They are
made of light magnesium or aluminum alloy. Some kinds even look similar to the old
artillery wheels, and in fact they are very light strong. The same concept is used for the
aircraft landing wheels. |
