1) Bicycle drivetrain 
The crankset (in the US) or chainset (in the UK), is the component of a bicycle drivetrain that converts the reciprocating motion of the rider`s legs into rotational motion used to drive the chain or belt, which in turn drives the rear wheel. It consists of one or more sprockets, also called chainrings or chainwheels attached to the cranks, arms,....
composed of cranks and chainrings
Lever arms attached to the bottom bracket via an axle. The pedal is attached at one end and the chainrings at the other via a spider.