Abstract: Driving means in particular for a cutting-off device with a rotationally held cutting-off tool. In order to provide the cutting-off tool with high acceleration in a simple manner, a sledge hammer (6) is provided that cooperates with an impact surface (5) arranged on a rotationally held cutting-off tool (4). Furthermore, a cam (2) is arranged on at least one driven rotating inertial body (1) for acting upon said sledge hammer, whereby said inertial body (1) is driven at an essentially constant, optionally adjustable speed.

Abstract: A process and machine for fabricating a rotation body having different diameters along the length thereof is disclosed, in which a blank is rotated and worked between two pressure zones to apply thereto a local pressure exceeding the flow limit of the blank material whereby circularly extending impressions of the different diameters are worked into the blank, the pressure zones crossing each other. The pressure zones are displaced relative to each other while applying the local pressure, the displacement motion having a component extending in the longitudinal direction of at least one of the pressure zones and the points of intersection of the crossing pressure zones forming a geometric line, and the blank is displaced in dependence on this line and on the different diameters to be produced.

Abstract: A method of cutting a piece of pipe from a length of pipe in a cutting plane by gripping the length of pipe directly adjacent the cutting plane and displacing the piece of pipe with respect to the length of pipe in the cutting plane, comprises applying a radially outwardly directed and a radially inwardly directed pressure against the length of pipe and the piece of pipe in the cutting plane and at both sides thereof, simultaneously applying an axial pressure, the pressures generating a stress amounting to at least 70% of the yield point of the material of the pipe, and maintaining the pressures during the entire cutting operation. A device for carrying out this method is also disclosed.