the sleeve 30 where the radially outer margin of the membrane spring 60 contacts and is optionally connected there with material continuity to the sleeve 30 in the example likewise shown in partial section in fig5 compressive forces and pulling forces are likewise applied mechanically a cut out 11 is also made as a blind hole here a ring shaped element 90 is connected to the holding element 1 by a weld connection 100 b with material continuity at the rear side 6 of the holding element 1 and surrounds the outer margin of the rear side opening of the cut out 11 the mechanically acting element is formed as the actuator 20 with two ceramic or metallic sleeve elements 80 and 80 which are e g connected to one another by a weld connection 100 c with material continuity in this example the two sleeve elements 80 and 81 are made almost the same in geometry and dimensioning an internal thread 31 into which the screw 32 is introduced is likewise formed at the sleeve element 81 which is arranged in the interior of the cut out 11 an aperture 39 through which the screw 32 is guided in a clearance fit is present in the outer end wall region of the outer sleeve element 80 in this respect the screw head is supported at the outer end margin of the outer sleeve element 80 two check nuts 33 are fastened to the screw 32 here this fixing can however also be achieved differently with an element rigidly fastened to the screw 32 there both sleeve elements 80 and 81 are connected with material continuity to the ring shaped element 90 if the screw 32 is now rotated and the two sleeve elements 80 and 81 are thereby pressed.