Gears are toothed wheels designed to transmit torque to another gear or toothed component. The teeth of gears are shaped to minimize wear, vibration and noise, and to maximize the efficiency of power transmission. Gears and the use of gears are essential to daily living and can be found in mechanical devices as well as everyday household objects.
Gears have been around for hundreds of years. The first mention of gears came from Aristotle in the year 330 BC, who used the devices for various construction jobs. He observed that the direction of rotation is reversed when one gear wheel drives another gear wheel. At that time, gears were also used in making water-raising devices and to make catapults.
Today, gears are used on a daily basis. They are found nearly everywhere—in clocks, cars, odometers, scales, conveyor systems, meters and VCRs, just to name a few examples. Manufacturing companies rely on several various sizes of gears for production. Gears are also found in most mechanical devices.
The job gears provide is essential. They provide gear reduction in motorized equipment. This motion is important because when a motor spins fast, it can provide enough power, but not enough torque. Torque is the force causes rotation. With gear reduction, speed output can more easily be slowed or reduced.
Gears are used for several reasons. They serve to keep the turning or rotation of two axes together. Gears can increase or decrease the speed of rotation and can easily be used to reverse the direction of rotation. Another reason gears are essential is that they transmit rotational motion to a different axis.
Gears are round. On the edge of the gear are teeth. The teeth of one gear fit into the gear of another gear. The teeth prevent slippage between the two gears. The number of teeth on the gear determines the gear ratio.