GB1260459A - Improved screen for winnowing fans - Google Patents

Abstract

1,260,459. Winnowing fan. ALLIS-CHALMERS MFG. CO. 7 July, 1970 [18 July, 1969], No. 32909/70. Heading A1F. [Also in Divisions B2 and F1] A winnowing fan 11 of a combine harvester has at least one air inlet opening 21 provided with a self-cleaning screen comprising a number of spaced elements 27 flexible in their length and carried by, and circumferentially arranged around, a hub 22 mounted on and rotatable with the shaft 18 of the fan 16 adjacent to the inlet opening, the elements 27 projecting from the hub to an extent to overlap the periphery of the inlet opening. The elements 27 may be of circular cross-section and may be made of spring steel wire, which may be chromium plated, or of plastics materials, e.g. nylon, and in the latter case they may be formed integrally with the hub 22 which may be made of two parts 23, 24 clamped together. The elements 27 may project radially or tangentially from the hub and may be straight or curved. In operation, debris, e.g. leaves or stems, drawn up to the air inlet openings 21 by the suction of the fan, is prevented from entering the openings by the rotating elements 27. The debris is either chopped-up by the rotating elements to a size small enough to pass through the elements and into the fan, or is thrown off the elements by centrifugal force, thus keeping the entrance to the air inlet openings unobstructed. Also, due to their flexibility the elements vibrate as they rotate thus further aiding in dislodging debris from the screens.