Disc cartridge having an opening/closing slider mechanism

A disk cartridge adapted to be loaded between two opposed heads of a disk drive comprising;

• a cartridge case having two sides which define a space for receiving a disk which is rotatable about an axis;
• a shutter plate-receiving surface in each side of the cartridge case for allowing a shutter-plate means to slide therein, the shutter plate-receiving surface being recessed relative to a side surface of the cartridge case and extending rearward from a front edge of the cartridge case so as to form a shutter plate receiving recess;
• a head insertion window formed in each of the shutter plate-receiving surfaces, a front end of each window being defined by a reinforcement portion constituting a part of the front edge of the cartridge case, the reinforcement portion having a stepped cut-out portion, of a thickness smaller than a thickness of the cartridge case at the shutter plate-receiving recess so that the stepped cut-out portion can be passed through a spacing between two opposed heads of the disk drive upon loading of the disk cartridge into the disk drive;
• a slider slidably mounted to the front edge of the cartridge case;
• and,
• guide means, formed in the front edge of the cartridge case, for guiding a sliding motion of the slider, said guide means being located longitudinally outward of each end of the reinforcement portion;
• wherein the shutter plate means is mounted to the slider for covering and uncovering each of the windows upon sliding movement of the slider;
• wherein the slider includes:
• a front portion, situated at a front position in a loading direction of the disk cartridge;
• a head insertion portion, adapted to be situated at the front end of the window when the shutter-plate means is moved to an uncovering position for fully uncovering the window, said head insertion portion being of a thickness small enough to be passed through the spacing between the two opposed heads of the disk drive upon loading the disk cartridge into the disk drive;
• a shutter-mounting portion situated at one end of the head insertion portion and of a thickness greater than the thickness of the head insertion portion, the shutter-plate means being fixed to the slider at the shutter-mounting portion;
• a pin engagement portion, situated at the other end of the head insertion portion and of a thickness greater than the thickness of the head insertion portion;
• and
• a pair of rear portions, situated at a rear position relative to the loading direction of the disk cartridge and connected, respectively, to the pin-engagement portion and to a part of the shutter mounting portion, which is remote from the pin engagement portion, through respective ones of a pair of connection portions so that one of the pair of rear portions and an associated one of the pair of connecting portions are moved longitudinally outward of each end of the reinforcement portion upon sliding movement of the slider covering and uncovering the shutter-plate means, each of the connecting portions having a thickness smaller than a thickness of the pair of rear portions, thereby defining at either side thereof a guide step to be engaged with the guide means.