a machine for digging up potatoes, removing the tops and dirt from the tubers, and throwing the tubers out onto the field.
USSR industry produces the elevator-type (KTN-2B), riddle-type (KVN-2M), and spinning-type (KTN-1A) potato diggers. Similar types of potato diggers are produced abroad. The elevator type has shares for digging up two rows of potatoes and three elevators (two primary rod-link types and a cascade rake) that loosen and sift the soil. The bulk matter that is caught goes to a vibration screen and excess soil and small impurities fall through the holes in it. The tubers, tops, and remaining impurities fall from the screen to the surface of the field. Then the tubers are picked up by hand. The riddle-type potato digger has a double-screen riddle instead of the rod-link elevators. The shares of this digger are secured to the front edge of the first screen and vibrate together with it. This arrangement gives better pickup on the layer of soil being dug. A screen similar to the vibration screen of the elevator-type digger is secured on the end of the second screen of the sifter. The spinning-type digger has a share that digs up one row of potatoes and a turning rotor that catches the dug-up row and throws the bulk material onto the field.
All the potato diggers are mounted implements; their working parts are driven by a takeoff shaft from the tractor engine. The productivity level of the KTN-2B is 0.30–0.45 hectare (ha) perhr; of the KVN-2M, 0.36–0.42 ha per hr; and of the KTN-1A, up to 0.4 ha per hr.