Abstract: A valve block arrangement configured as a closed center system includes at least one main spool for controlling a hydraulic consumer. The main spool is configured to open and close at least one pressure medium connection between a hydraulic pump and the consumer in controlled, continuous fashion and, in at least one embodiment, is electrically activated. A bypass flow path with a cut valve branches off between the adjustable, hydraulic pump and the main spool. The cut valve is configured to open and close a pressure medium connection between the hydraulic pump and a tank in controlled, continuous fashion. The cut valve is electrically activatable.

Abstract: A valve block arrangement configured as a closed center system includes at least one main spool for controlling a hydraulic consumer. The main spool is configured to open and close at least one pressure medium connection between a hydraulic pump and the consumer in controlled, continuous fashion and, in at least one embodiment, is electrically activated. A bypass flow path with a cut valve branches off between the adjustable, hydraulic pump and the main spool. The cut valve is configured to open and close a pressure medium connection between the hydraulic pump and a tank in controlled, continuous fashion. The cut valve is electrically activatable.

Abstract: In a method and a device for creating a symbol in a workpiece surface via stamping (scoring or plastic forming under compressive conditions); the resultant stamping depth is measured and/or regulated constantly by using a distance sensor which is mounted on the stamping needle and is movable therewith. The stamping needle is placed on the workpiece surface before stamping is begun, thereby resulting in a first distance between the distance sensor and the workpiece surface. A second distance between the distance sensor and the workpiece surface is obtained during the subsequent stamping procedure, and when the stamping needle is pressed into the workpiece surface. The stamping depth results from the difference of the two distances.

Abstract: In a method and a device for creating a symbol in a workpiece surface via stamping (scoring or plastic forming under compressive conditions); the resultant stamping depth is measured and/or regulated constantly by using a distance sensor which is mounted on the stamping needle and is movable therewith. The stamping needle is placed on the workpiece surface before stamping is begun, thereby resulting in a first distance between the distance sensor and the workpiece surface. A second distance between the distance sensor and the workpiece surface is obtained during the subsequent stamping procedure, and when the stamping needle is pressed into the workpiece surface. The stamping depth results from the difference of the two distances.

Abstract: The invention relates to an apparatus for underground tunneling. It has a working tube which can be driven in the drilling direction and a digging unit mounted therein, and it has a cutterhead which can be shifted back and forth and radially of the axis of the apparatus. When the cutterhead is not deflected radially, the entire digging unit has a substantially smaller cross section than corresponds to the internal cross section of the working tube. A scoop disposed on the floor of the working tube and provided with a shovel-like mouth at its front end serves for the simple and cost-effective removal of the earth loosened by the cutterhead. The scoop is at first urged forward out of the working tube by means of a drive mechanism in order to shovel up loosened earth, and then it is withdrawn rearwardly out of the working tube, emptied, and run back again into the working tube.