Abstract: A pneumatic arrangement for the tensioning of a tape in a machine for loading magnetic tape onto a cassette, having a closed tensioning mechanism containing container that is under a vacuum for forming a tension loop in the tape and having curved elements for the guiding the tape at the inlet and outlet of the container, wherein the tensioning mechanism container and the outlet guiding element are pivotably mounted to be controllably moved between two indicated positions in order to be able to align the outlet guiding element at one instance, to a first processing station of the machine and, at another instance, to a second processing station of the machine without causing undesirable vibrations of the tape itself.