Spur gears are the most gear box for greenhouse typical type of gears. They possess straight teeth, and so are mounted on parallel shafts. Sometimes, many spur gears are utilized at once to create large gear reductions.
Spur gears are used in many products that you can see around HowStuffWorks, like the electric screwdriver, dance monster, oscillating sprinkler, windup alarm clock, washing machine and clothes dryer. But you won’t find many in your vehicle.
This is since the spur gear could be really loud. Whenever a equipment tooth engages a tooth on the additional gear, one’s teeth collide, which impact 
makes a noise. It also increases the stress on the gear teeth.
To lessen the noise and tension in the gears, the majority of the gears in your vehicle are helical.