Gears are used in tons of mechanical devices. They do several important jobs, but most important, they 
offer a gear decrease in motorized equipment. This is key because, often, a little motor spinning very fast can provide plenty of power for a gadget, but not enough torque. For instance, an electric screwdriver includes a large gear reduction since it needs lots of torque to carefully turn screws, but the electric motor only produces a little amount of torque at a higher speed. With a equipment reduction, the reducers for greenhouse output speed could be reduced as the torque is increased.
One more thing gears do is usually adapt the direction of rotation. For instance, in the differential between the rear wheels of your car, the energy is usually transmitted by a shaft that runs down the guts of the car, and the differential has to convert that power 90 degrees to use it to the tires.
There are a lot of intricacies in the different types of gears. In this article, we'll learn exactly the way the teeth on gears function, and we'll talk about the various types of gears you find in all sorts of mechanical gadgets.
Basics
On any gear, the ratio depends upon the distances from the guts of the gear to the point of contact. For example, in a device with two gears, if one gear is twice the size of the additional, the ratio will be 2:1.
One of the most primitive types of gears we could look at would be a steering wheel with wooden pegs protruding of it.
The problem with this type of gear is that the length from the center of each gear to the idea of contact changes as the gears rotate. This means that the gear ratio changes as the apparatus turns, and therefore the output swiftness also changes. If you used a gear like this in your car, it would be impossible to maintain a constant speed -- you'd be accelerating and decelerating constantly.
Many contemporary gears use a special tooth profile named an involute. This profile has the very important house of maintaining a constant speed ratio between your two gears. Like the peg steering wheel above, the contact point moves; but the shape of the involute gear tooth compensates because of this movement. Observe this section for details.
Now let's check out some of the various types of gears.