designed so that it is conical in its non tensioned state to assemble disk spring 9 need only be brought against a radial shoulder with lever 2 u2033 of disk spring 2 and is then supported by a corresponding shoulder of central release element 10 when this is used when central release element 10 reaches its assembly position disk spring 9 is also in the position shown in fig1 40 the embodiment shown in fig2 corresponds essentially to the embodiment described previously only the assembly shoulder of central disengagement element 10 is used as a lever instead of roller 11 41 in the embodiment of fig3 in contrast with the previous embodiments the centrifugal forces play only a subordinate role in this embodiment a disk spring 16 shown as two disk springs angled against one another is supported directly on ball bearings 17 which are capable of being displaced axially against one another on a central retaining device 18 the centrifugal forces which are encountered in disk spring 16 are largely compensated for in this embodiment of disk spring 16 42 the embodiment shown in fig5 and 6 corresponds essentially to the embodiment of fig1 except that instead of rollers 11 ball bearings 11 u2033 are provided to support the oblique area 10 u2033 u2032 in addition to this spring.