Abstract: In a rotational working cylinder comprising a shaft arranged concentrically within the working cylinder and driven out of the working cylinder with at least one end of it, a piston being divided into two piston portions perpendicularly to the shaft and the piston portions being held in tensed position in respect to each other, forced trajectories between the working cylinder and the piston portions as well as between the piston portions and the shaft, respectively, at least one of the forced trajectories is formed as a longitudinal spiral path, and the piston portions are locked in relation to each other for maintaining the tensed position of the piston portions in all operational positions and loads of the working cylinder.