After passing through this first set of concave teeth, the straw drops down into a device for refeeding into the second set of teeth at the back of the cylinder. This refeeder is attached to the shaker and has much the same motion. The refeeder in turning the straw over shakes out the loose peas and throws the straw up into the second set of concave teeth, which removes any peas there may be left in the pods, and cuts the straw into convenient lengths for feeding […]
Source: wiktionary