Head access door, opening mechanism and method of sealing

A head access door mechanism for a cartridge having a top, a bottom, and sides and containing a magnetic disc nominally parallel to said top and bottom, the door of said door mechanism, when closed, sealing the head access opening on the side of the cartridge against a seal adjacent to said opening, the mechanism providing a means to prevent the opening of said door except during the proper operation of the cartridge and comprising:

• grooves located adjacent to said head access opening in the top and bottom of the side of said cartridge, said grooves being narrower in the area close to said head access opening and wider in the area beyond said seal on a first side of said head access opening;
• a substantially flat door slideable linearly along its length in said grooves over said head access opening;
• a protuberance positioned on the side of said door toward the inside of said cartridge and protruding toward said door, said protuberance located slightly beyond the end of said door adjacent said first side of said head access opening when said door is closed and in the area where said door slides while opening;
• and
• a rotatable bellcrank located within said cartridge having a first arm coupled to said door near that end of said door located toward the side of said head access opening where said door slides while opening, said bellcrank being spring-loaded to rotate to force said door closed and against said seal and said end of said door inward slightly beyond said protuberance so that said protuberance interferes with said end of said door and prevents said door from opening when a force is applied directly on said door at said head access opening, said bellcrank having a second arm to which a force may be applied to overcome said spring-loading and to rotate said first arm to force said end of said door outward beyond the point where it interferes with said protuberance and to force said door away from said head access opening, said door sliding in said grooves to open said head access opening.

A cartridge for a magnetic disc or the like having a head access opening in its side through which magnetic heads are insertable when the cartridge is placed in a disc drive assembly comprising:

• a substantially rigid and flat door in said cartridge adjacent said side in said opening, said door linearly slideable along its length in one direction across said opening to seal said opening and in the opposite direction along said side to uncover said opening;
• guide means along side adjacent said door for guiding said door as it slides across said opening and along said side;
• a protuberance positioned on the side of said door toward the inside of said cartridge and slightly beyond the end of said door when said door seals said opening, said protuberance facing said door and located slightly beyond the path along which said door slides to seal and uncover said opening;
• a rotatable bellcrank locted within said cartridge, the axis of said bellcrank being generally parallel to said door, said bellcrank located generally on the side of said opening along which said door slides to uncover said opening, said bellcrank having a first arm and a second arm, said first arm coupled to said door near its end so that said door slides along its length to seal said opening when said bellcrank is rotated in one direction and to uncover said opening when said bellcrank is rotated in the other direction, said bellcrank forcing said end of door inward beyond said protuberance when said bellcrank is rotated so that said door seals said opening, whereby a force on said door applied through said head access opening from outside the cartridge cannot cause said door to slide to uncover said opening;
• and
• a biasing means for rotating said bellcrank so that said door seals said opening.