Examples of bevel gears include gears that grind grain in mills. Bevel gears are also found in doors that open and close by sliding up or down, as in garage doors. They are also found on the wheels of shaft-driven bicycles, egg beaters and hand drills.
Bevel gears are also useful in the transportation and defense industries and in cooling towers, powerplants and the printing industry.
Bevel gears are circular and have toothed edges, but the edge and the teeth are at angles to each other. When two bevel gears are engaged, the motion between them is transferred at a different angle, which is usually a right or 90-degree angle. Bevel gears are used when the speed and direction of a shaft rotation needs to be easily changed.
There are several types of bevel gears. The straight bevel gear has cone-shaped teeth and engages with a gear that has the same type of teeth. When the gears are the same size and have the same number of teeth, and the shafts are at a right angle to each other, they are called miter gears. The teeth of straight bevel gears can also be curved. In that case, it is called a spiral bevel gear. Other bevel gears are hypoid and zero bevel gears.