Abstract: A system and method for accurately positioning a transducer means radially in alignment with a selected data track on a magnetic disc and maintaining it in radially alignment is described. Sectored servo tracks radially interspersed with data tracks on a magnetic disc, are uniquely encoded within groups, the code comprising the location of recorded servo signals at either a first or second position within a plurality of data frames located on the servo tracks. The recorded servo signals are detected by a transducer and compared with a D.C. voltage in a comparator in order to produce a series of clock pulses for a shift register. A predetermined sequence of pulses corresponding to possible locations for recorded servo signals within the data frame in a sector is the data input to the shift register. The output of the shift register is a binary number corresponding to the servo track or the data track with which the transducer is radially aligned.

Abstract: A head access door mechanism for a cartridge containing a magnetic disc is described. The mechanism employs a bellcrank, located inside the cartridge, to which the door for the head access opening is coupled. The door slides in grooves located along the top and bottom of the side of the cartridge. The bellcrank is spring-loaded and forces the door closed and inward against a seal located around the head access opening. An interfering lip located along the inside of the groove slightly beyond the end of the door when the door is in the closed position interferes with the door so that it cannot be opened by a force applied directly to the door at the head access opening which would tend to slide the door within the groove. When inserted into a disc-drive assembly, a pin in the disc-drive assembly exerts a force on the second arm of the bellcrank to overcome the spring-loading.

Abstract: A mechanism for restraining a magnetic disc within a cartridge and for sealing the cartridge when the cartridge is not in use is described. The present invention has one or more spring-loaded members located on the bottom of the cartridge which are coupled to the cartridge but movable with respect to it and which are separate from the rotatable hub assembly to which the magnetic disc is clamped within the cartridge. The spring-loaded member or members press in an axial direction against a surface on the hub to force together the overlapping sealing surfaces on the hub and the cartridge, thus sealing the cartridge and preventing the hub assembly and magnetic disc from rotating when the cartridge is not in use. When the cartridge is inserted into a disc-drive assembly, release pins overcome the spring-loading of the member or members and allow the sealing surface on the hub assembly and cartridge to separate.

Abstract: An actuator for linearly moving magnetic heads in which an open-ended carriage assembly extends down both sides of the magnet structure in order to provide a much shorter actuator assembly than is typical is described. The loading mechanism is not mounted upon the carriage assembly, thereby allowing the actuator to have a higher resonant frequency than those actuators which carry a more complex structure on the carriage assembly. The magnet structure is in the shape of an E with the motor coil, which is mounted across the open end of the carriage assembly, moving along this center section of the magnet structure. Alignment pins located at the other end of the carriage assembly allow the magnetic head arms to be mounted and aligned quickly and with precision.

Abstract: A mechanism for loading and unloading magnetic heads from the surfaces of a magnetic disc is described. The invention uses lift rods which are pivoted about a portion of their length and have offset sections which cooperate with the head lift arms or mounting flexures upon which the magnetic heads are mounted. The lift rods are controlled through other offset sections located along their lengths. These other offset sections, in the preferred embodiment, are pressed against conical surfaces which are oriented so that the axes of the surfaces are in a direction perpendicular to the pivoting axes of the lift rods. Movement of the conical surfaces toward and away from the pivoting axes of the lift rods imparts an arcuate motion to the offset sections of the lift rods with which they cooperate, and this correspondingly produces arcuate motions in the offset sections which cooperate with the head mounting flexures. By this motion, the magnetic heads are gently loaded or unloaded onto or from a magnetic disc.