Abstract: The positioning device for the magnetic head (14) of a magnetic disc store (1) is constructed so that the heat produced by the stepping motor (6) has no significant influence on the magnetic-head support (2). For this purpose the stepping motor (6) is arranged on a mounting plate (5) made of a material with a low thermal expansion coefficient. This mounting plate (5) is secured to the chasis (3) of the drive mechanism. Between the stepping motor (6) and mounting plate (5) a foil (8) with satisfactory heat-sinking properties is arranged.

Abstract: A centering and clamping device for a flexible foil includes an expanding cone which expands an expanding mandril via at least one resilient element, the force that can be transmitted to the expanding mandril by the resilient element at the location of the transition between the conical and the cylindrical portion of said mandril being greater than the force required for widening the opening in the foil but smaller than the force required for a substantial elastic deformation of the expanding mandril beyond the cylindrical inner bore of the hub, which bore terminates at an end surface. The expanding cone comprises a flange which urges the flange of the expanding mandril onto the foil.