Abstract: A method for producing workpieces with surfaces of non-circular but regular cross-sections with a working tool, wherein the workpiece is rotated about its own axis and the axis of the workpiece is rotated around an axis being eccentric to the axis of the workpiece and the two rotations being brought into a certain relationship according to the surface to be generated. According to the invention the axis of the workpiece is rotated mechanically independently from the eccentric axis and the relationship between the two rotations is established and maintained by an electrical control into which parameters of the surface to be produced are fed and with which the rotations of the axis are monitored and, in dependency of the fed-in and monitored factors, into rotational drives of the axes is interfered, respectively.

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.