a tensioning device is so constructed that even thin - wall parts to be clamped can be secured and clamped reliably radially as to a driving shaft . during tensioning procedure , radial forces need not be taken up by a part to be clamped . for this purpose a force taking - up part is provided which is seated in a region of tensioning cones upon this part to be clamped or secured . for this reason very thin - wall construction can be employed and nevertheless reliable clamping radially upon the driving shaft can occur because the force taking - up part hinders and prevents that any thin - wall part is radially widened and expanded . with the tensioning device therefore it is also possible to clamp thin - wall parts , as for example thin - wall hollow shafts , with coarse - tolerance driving shafts and with driving shafts of differing basic diameter to be clamped radially in a reliable manner . upon one of the parts to be clamped in a region of tensioning cones at least one force taking - up part is arranged which receives and takes up the radial forces encountered during tensioning procedure and being operatively connected with a tensioning element .