# What are gears and their function

## gear

Gears on a machine: If the smallest gear turns once, then the middle one only makes about half a turn because it has almost twice as many teeth. The large gear then turns even less and also more slowly. That is a small gear.

A toothed wheel is a specially shaped wheel: it has teeth, which are also called “teeth”. These teeth can mesh with the teeth of another gear, and when one wheel turns, the other moves with it.

Gear wheels come in different shapes and sizes, and also made of different materials. Sometimes you can still find some made of wood in old windmills. Today they are mostly made of metal or plastic.

Gears have the advantage that they cannot slip on each other. In the rack railway, the gears engage in a rack. In this way, the train can cope with steep stretches. The smooth iron wheels would turn idle on the rails.

On a bicycle, the gears mesh with the chain and from there back onto gears on the rear wheel. These gears are actually called sprockets. Before this invention, the pedals were mounted on the axle of the large front wheel. This vehicle became known as a penny farthing.

### What can several gears do together?

Most engines turn too fast, for example car engines. But technically there is no other way. Therefore you have to reduce the speed. This can be achieved with the clever arrangement of several gears. Everything together forms a transmission.

When a small gear with a few teeth meshes with a larger gear with more teeth, the larger gear rotates more slowly than the smaller one. You can do this several times in a row using technical tricks until you reach the correct number of revolutions per minute. When it comes to the transmission of a car, you can also choose different levels, the “gears”.

With a bike you get exactly the opposite. The driver moves a large gear wheel with the pedals. There are various smaller gears on the rear wheel. This means that the driver has to pedal less and can even select different gears. Depending on which gear he chooses, he can drive at different speeds. The higher the gear, the faster it can go. But it also needs more power than in a low gear.

• Sprockets of a gear shift on a bicycle

• This special design is called worm gear.

• A cog railway can drive up particularly steep slopes.

There are also other search results for “cogwheel” from Blinde Kuh and Ask Finn.

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