|Gears are used in tons of mechanical devices.
They do several important jobs, but most important, they provide a gear reduction in motorized equipment.
This is key because, often, a small motor spinning very fast can provide enough power for a device, but not enough torque.
With a gear reduction, the output speed can be reduced while the torque is increased.
Another thing gears do is adjust the direction of rotation.
If you want to create a high gear ratio, nothing beats the worm gear.
In a worm gear, a threaded shaft engages the teeth on a gear.
Each time the shaft spins one revolution, the gear moves one tooth forward.
e.g If the gear has 40 teeth, you have a 40:1 gear ratio in a very small package.