Simple Power Machines 


Structures utilizing wind, water and muscle power in their operation are
called simple power machines. They have a common characteristic i. e. they relate somewhat to to the treshing.
First one put the wind to work in sail to drop the tiring and heavy rowing.
Later the sails presented themselves in wind wheels driving waterwheels and mills.
It is difficult to decide when the windmills appeared. It is certain that they were already used in the first century B. C. There was a report by a Swedish researcher SVEN HEDIN at the beginning of the twentieth century about a wind power machine found at the Afghan-Iranian border in town NEH. The machine was built in the first-second thousand years B. C. This power which have been reconstructed consists of several vertical axis windwheel serving for irrigation water lifting.


The vertical axis wind wheels were followed by the horizontal axis ones spreading gradually in the whole world. (It has the advantage that it can be adjust to wind direction easily.) In Egypt and Grecian Isles ancient horizontal axis windmills were used to which a lot of ruins and objects being in usage upto now bear witness.
The earliest note about the horizontal axis windmills in Europe is from the ninth century (Anglia). Their prevelance was already wide in the seaside countries of Western Europe in the 12th century, while they occupied farther countries so the Carpathian Basin, as well in the 16-17th centuries. Beside windmills, wind power machines were being used in more places in an increasing number to drive pumps, generators and little machines.


The dense then rare blade windwheels spreaded in the second half of the 19th century and the peak form of them were the propeller wind turbine constructed in the 20th century.
In the field of agricultural production the transport, irrigation and processing were the branches where the water power utilization developped in the greatest extent.
Water energy can be utilized in two way as kinetic energy (river water) or as potential energy (running from a higher downward).


The kinetic energy of water could be known even by the prehistoric man.
From the year 4000 B. C. the tubboat and different type papyrus, corkwood,
bulrush, catamaran and inflatable animal skin rafts are already known. These
boats were often equipped with sails of bulrush.
The waterwheel making use of both type of energy of water is known from the beginning of our era. In the 3rd century of our era waterwheel mill ground the grain in Gallia (28 tons cereal grain was ground during 24 hours). A Roman architect Vitruvius described the principles of watermills.
In Europe the waterwheels became general together with windmills. The kinetic energy of water is utilized by the shipmillwheel, while the potential energy drives undershot, middleshot or overshot waterwheels. There are notes of the age about watermills, waterharnesses, sawmills. They might spread more widely in the 17-19th centuries. The highest level utilization of the water energy have been got by discovering and appliing water turbines.


The simple power machines driven by muscular power are known from the ages B. C.
The treadmill pumps noted from 1000 B. C. were already operated by animals.
A typical form of the simple machines driven by man muscle power constructions is the TREADWHEEL which was already used in Mezopotamia in 220 B. C. to operate irrigation system.
Smaller or bigger alterations of treadwheels remained until the end of 17th century. It occured that 25-50 persons kept accelerating run in a tread wheel lor driving.
The drives, treadmills according to our current knowledge are known from 1480 as a mine pump application driven by horses. That time simple treadmills was used in agriculture only for irrigation. There was not any development in the treadmill structures from the 17th century. The simpler, open "spur gear) drives were followed by more closed ones being draftable (transferable) bell drives.

2011 © Minden jog fenntartva!