Abstract: A method and apparatus for threshing ribs from tobacco leaves and the like. The method comprises a basket having a grid in which a threshing gear formed with a rotary drum including teeth on its periphery is accommodated in such a manner that the outside portion of the gear is disposed spacedly adjacent to it, supplying raw material to the space between the threshing gear and the basket from one side of the axial direction by an air flow at a predetermined speed corresponding to the peripheral speed of the gear, rotating the gear and basket at different peripheral speeds and discharging raw material toward the crossing direction of the axis. The apparatus comprises a casing, a threshing gear formed with a rotary drum having teeth, a basket having a grid and surrounding the gear, the gear and basket being rotated at different peripheral speeds, a material supply port, a feed duct and a discharge opening.

Abstract: A knife abrasive apparatus for a rotary drum shaped cutter can grind the knife edge without causing it to be serrated. It has a rotary drum shaped cutter including a rotary drum and knives spacedly disposed on the outer periphery of the drum at a predetermined helical angle to a virtual surface which blade edges of the knives will draw. It also has an abrasive wheel to be used for grinding the edges. The wheel is declined at the rotary center axis with respect to a vertical plane to the rotary center axis of the cutter so that a composite vector composed of a peripheral velocity vector of the cutter and that of the wheel will become parallel to each of the edges in the longitudinal direction of each of the knives. The velocity of rotation of the cutter and the wheel is controlled to maintain the ratio of the peripheral velocity of the former and the latter constant. The abrasive wheel is supported by a movable supporting member.