Chuck arrangement for a floppy disk drive for accurately and positively engaging a floppy disk

摘要

A hub base 1, having a height not larger than 4.5 mm from an upper surface of a copper foil on a printed circuit board 5, is fixed with a rotor frame 2. A medium holding magnet 3 is provided around hub base 1 and integral with rotor frame 2. A leaf spring 6 is swingably supported on rotor frame 2. A drive pin 8 is mounted on leaf spring 6. An index magnet 10 is integrally formed with rotor frame 2. A magnetization pattern applied on medium holding magnet 3 is in-phase with a magnetization pattern applied on index magnet 10. An upper end of index magnet 10 is positioned lower in height than a top of medium holding magnet 3 which protrudes from an upper surface of rotor frame 2.