Cartridge for optical data discs

An optical disc is enclosed in a protective cartridge (20) including a pair of interlocking plastic shells (53, 54). The shells have integral resilient fastening hooks which are locked by plugs to prevent disassembly. A two-piece sliding door (30) is opened for exposing the disc during a read operation. In one embodiment, the sliding door includes two metal shutters (51, 52) having forward portions stamped with resilient hooks which are permanently retained in an undercut groove (57) formed in a plastic slider engaged in a track defined by two plastic shells. The rear portions (60, 61) of the metal shutters are overlapped by respective shutter retainer strips (58, 59) secured to ledges formed in the shells. The door is urged towards a closed position by a double coil torsion spring (70) providing a substantially constant closing force along the range of travel of the slider. A pivot (110) having detent positions (113) is provided for selectible blocking of a write protect hole formed through the shells. An alternative embodiment of sliding door (30a) is disclosed which comprises two moulded plastic shutters (51a, 52a) that each have an integrally formed slider (121, 122) which are adapted for innerfitting engagement and for supporting the door for sliding movement relative to the cartridge shells. A locking lever (150c) also is disclosed for engaging the disc in response to movement of the door to a closed position for retaining the disc against movement during periods of non-use of the cartridge.