A cutting blade includes a first and a second elongated frame part, and projections protruding from the first and the second elongated frame part in the cross direction. The first and the second frame part are attached to each other by blades, the blades being individually attached to the first frame part at first pivot points and to the second frame part at second pivot points so that the opposite ends of the blades protrude from the first and second pivot points, respectively, in the cross direction of the frame parts. The first and the second elongated frame part are movable relative to each other to rotate the blades around the first and second pivot points and to generate a cutting movement between each end of the blade and projection approaching each other.