Magnetic recording disk cartridge

摘要

A magnetic recording disk cartridge is provided with an opening in its casing and a swingable erasing preventing unit inside the casing which can assume an open position in which a probe in the device in which the cartridge is used can enter the opening to detect that the cartridge is in an erasing prohibited condition or a closed position in which the probe is prevented from entering the opening to detect that the cartridge is in an erasing permitted condition. The erasing preventing unit has a detent which holds it in the open position until released by two coordinated actions and a lockarm which holds it in the closed position until pushed with the finger, thus precluding misoperation.