Which mechanism did Watt adopt to convert the engine's vertical action into continuous rotary motion, while avoiding existing patents?

Answer

The sun and planet gear

Watt and his team adopted the sun and planet gear mechanism to achieve rotary motion, as the concept of a crank was patented by others.

Which mechanism did Watt adopt to convert the engine's vertical action into continuous rotary motion, while avoiding existing patents?
inventionSignificanceengineSteamWatt