A combine harvester is a specialized agricultural machine designed to efficiently harvest cereal crops, such as wheat, oats, and rice, by combining the actions of reaping, threshing, and winnowing in a single pass. The machine utilizes a cutting header to sever the stalks and feed the material into an internal threshing cylinder. This process separates the harvested grain kernels from the rest of the plant material, including stalks and chaff. Following threshing, a cleaning mechanism, often involving sieves and airflow, removes the lighter debris, ensuring that only the pure grain is collected into a designated grain tank. This technology significantly increased the scale and speed of grain harvesting relative to older, manual methods.