Model 4U harvesters of yams are suitable  for potatoes,sweet potatoes,garlic and other root crops, it is composed of components such as cutting seedling organization, field wheels,girders,excavating a shovel, transporting chains, choosing sieve, they can integraly complete the working procedures such as harvesting ,excavating,choosing, the series include the middle drive transmission and the left-side drive transmission for different types of tractors.