A disk cartridge with a write protect mechanism includes a cassette casing in which a disk is rotatably housed. The cassette casing includes upper and lower halves. The upper half includes a planar wall and a standing peripheral wall, and the lower half also includes a corresponding planar wall and a...http://www.google.de/patents/US5150269?utm_source=gb-gplus-sharePatent US5150269 - Disk cartridge with write protect mechanism
