A positioning device includes a positioning mechanism, a contacting mechanism located in the positioning mechanism, and a connecting mechanism located adjacent to an end of the positioning mechanism. The curvature of the contact surfaces deviates from zero in each direction. The particle size of this mixture is then further reduced, and transported to a centralized and stationary processing plant for digesting and emulsifying. The server system processes an available system bandwidth and the average system bandwidth usage to determine a maximum bandwidth authorization. To this end use is made of a bending mandrel to whose rigid head assembly of springy sheet metal lamellae is attached to improve the bendability of the bending mandrel while maintaining a satisfactory supporting action, the lamellae, with the exception of the outer lamellae, having window-like cutaway portions.