Abstract: Disclosed is a control device for a hydraulic steering device, having a control input device and an electrically operable valve for actuating a steering actuator of the steering device, which valve can be electrically actuated as a function of steering setpoint values detected at the control input device via at least one first control path between the control input device and the valve, wherein the control device is set up in such a way that the relevant first control paths can be deactivated as a function of steering setpoint values detected at the control input device via respective second control paths, which are assigned to this relevant first control path and differ at least partially from the respective first control paths when this first control path is active, or can be activated when this first control path is deactivated.

Abstract: An apparatus is configured to pull a single crystal of semiconductor material from a melt contained in a crucible. The apparatus includes: a rotatable pulling shaft; a rotatable crucible shaft; a double worm gear between a drive and the pulling shaft; and a further double worm gear between a further drive and the crucible shaft.

Abstract: The tamperproof document consists of a photographic material as information carrier which is laminated on one or both sides with a transparent foil. The foil is attached to the surface of the information carrier by a layer of adhesive containing poly-1,2-alkyleneimine. The document is eminently saft against falsification.