Abschnitt 5.2 - 5.2 Working on machine tools
5.2.1 Clamping cylinders
Machine tools may have hydraulic clamping devices, the structure of which can be very complex in some cases (see figure 27). These clamping devices can clamp "actively" by hydraulic pressure and be supported by a hydraulic accumulator or they operate according to the closed circuit current principle and generate the clamping force by spring tensioning. For releasing the clamped parts in the case of the closed circuit principle, spring tensioning is overcome through the use of a hydraulic cylinder. With this functional principle sudden pressure drops, e. g. due to hydraulic line failure, or a deadlock of the clamping system loosening suddenly as a result of the spring force can lead to pinch hazards for operators and maintenance technicians.
Fig. 27
Complex clamping module of a transfer line
5.2.2 Vertical slides on machine tools
Machine tools may have hydraulically elevated vertical axes or other axes loaded by gravity that are held in their position by means of hydraulic brake and holding devices. These vertical slides have to be considered in the same way as the elevated loads (see section 5.1.1).