Abstract: A device for chopping straw of the type which comprises a rotor arranged in an apparatus housing, said rotor having a plurality of knife arms detachably attached thereto and which when rotated pass between a number of counter-knives attached to a knife beam. The knife arms and counter-knives comprises flat bars provided with at least one sharpened edge on one of its long sides. The knife arms are arranged to act as fan blades guiding the air stream with chopped straw exiting from the apparatus housing, by the fact that each knife arm has said at least one edge bevelled in a respective oblique sharpening plane extending substantially throughout the thickness of respective knife arm. A desired spreading direction and spreading width of the chopped straw is obtained by arranging the detachable knife arms with their sharpening planes in different configurations with respect to each other.

Abstract: A device for combine harvesters (11) equipped with impact straw cutters (16) of the kind equipped with a cleaning device (13) for separation of chaff from the grain and which rotary chopper is connected to the straw outlet (17) of the combine harvester, whereby the chaff coming from the cleaning device (13) and being transported by a flow of air is intended to be supplied to the rotary chopper (16). The rotary chopper is connected to the straw outlet (17) of the combine harvester. The purpose of the invention is to provide a device by which the chaff is spread over the entire harvesting breadth of the combine harvester and is also efficiently admixed with the comminuted straw such that a continuous and even distribution can be obtained on the field.