Recording and reproducing disk cassette with improved, slidable shutter plate

摘要

A recording and reproducing disk cassette having a case accommodating a rotatably mounted disk which is partially exposed through first openings provided in the case which are normally maintained closed by a shutter plate which is moved when the cassette is loaded by the disk to expose the first openings, including first steps provided on the case at an elevation below the outer surface of the case, second steps provided on the case at an elevation below the first steps, the shutter plate being slidably mounted on the second steps, and a protective plate having second openings coinciding with the first openings of the case and being fixedly mounted on the first steps of the case such that the protective plate covers the shutter plate.