si 3 n 4 instead of the rollers 25 sliding bodies may also be provided in the variant according to fig2 and 22 a pivot pin is extended and forms the bearing pin 48 for the fork shaped holder 12 of the cam follower element 10 into which the valve stem 11 which is provided with a thread 28 is screwed in an adjustable manner and is fastened by the counter nut 27 in the schematic illustration according to fig2 and 27 the holder 12 is formed by a triangular axis of articulation in which the cam follower element is coupled to an additional bearing pin 48 the enclosing element shown in fig3 to 34 is again extension resistant and is designed as a band or the like fig3 shows a schematic possibility for storing the band by the excess length being guided in the form of a protuberance 34 via two deflecting rollers 36 which are parallel to each other and are kept at a distance and via a deflecting roller 38 which is pressed outward for example by means of a spring 30 a hydraulic piston cylinder or the like when the circumferential length is enlarged by the cam element 71 being extended or pivoted part of the enclosing element 6 is pulled in from the protuberance 34 as a result of which the spring 30 is more strongly compressed on return into.