The cutting mechanism (2) has knife that is movably mounted outside the crop channel. The knife is movably mounted on knife carrier. A resetting device is arranged for re-setting knife between non-cutting position and cutting position. A retaining unit is provided for retaining knife in cutting position or non-cutting position relative to the knife carrier. A deactivating unit is arranged for switching off or reducing the restoring force of resetting device. The cutting edge of the knife is inclined to the angle of 30-70[deg] and 45-55[deg] .
