Potato Harvesting Combine

a machine for digging up potatoes, removing their tops and dirt, and collecting them in a bin, either of the combine itself or of another vehicle.

In the USSR the KKU-2 Druzhba potato combine is produced in two versions: the elevator type and the riddle type. With the elevator type a stationary share undercuts the layer of soil and the rod-link elevator loosens it and sifts the soil. In the riddle type the share vibrates with the first sieve of the riddle. Most of the soil is sifted by the elevator or fiddle screen. The bulk matter coming from the sifting elements goes to the clod breaker, whose vacuum tanks break up clods. The pulverized soil is sifted through the screens of the riddle, and the remaining material goes to the rod-link conveyor of the top-removing device. The tubers and small impurities fall between the rods of the conveyor, and the tops, with tubers that have not been broken off, and plant residue catch on the rods and, after passing through a pressing conveyor, are thrown into the field behind the combine. While the tops are being pulled between the conveyors, clearing rods cut off the remaining tubers. The tubers and impurities (clods of earth, stolons, and stones) are fed to a table by a drum conveyor and from there to a sorting conveyor where workers remove them manually and place them on the waste conveyor, which throws the stones and clods into the field. From the sorting conveyor the tubers go to the loading elevator, which feeds them into a bin with a moving bottom. When the bin is filled, the tubers go to the bed of a self-loading trailer or are loaded into a dump truck.

The potato harvesting combine can be used to harvest potatoes on sandy, sandy loam, and light loam soils that are not stony (stones obstruct the machine). The riddle-type version can also be used on stony soils if the stones are small. The productivity of the combine is 0.2–0.42 hectares per hr; its operating speed is 1.3–4.0 km/hr. It is operated by a tractor driver and four to five workers.

Potato harvesting combines are used extensively in foreign countries. Examples include the Weimar machine in the German Democratic Republic, which has various modifications for harvesting potatoes planted with 62.5–70 cm interrow spaces; the one-row and two-row potato harvesting combines used in the Federal Republic of Germany for harvesting potatoes planted with interrow spaces up to 75 cm; and the Super Duplex combine in Great Britain. The operation of these machines is similar to that of the Druzhba potato harvesting combine.