In this system a toothed gear, known as the "sun" gear, is attached so it can spin around a rod that runs through the center of the gear. Another gear, called the "planet" gear, runs along a track that circles the sun gear. One end of a long, straight bar is attached to one point of the planet gear; the other end of the bar is attached to the beam of the engine. As the piston moves up and down, it moves the bar up and down. When the bar moves, it moves the planet gear along the track. As the planet gear moves, it causes the sun gear to move in a circle.
