Magnetic disk drive

A magnetic disk drive for a removable magnetic data recording medium comprising:

• a disk insertion position detecting sensor which detects a fully opened position of a shutter of a removable magnetic data recording medium;
• a controller responsive to the disk insertion position position detecting sensor for generating a driving signal;
• an actuator operable in response to the driving signal from the controller;
• upper and lower carriages elastically supported on a movable member that is moved back and forth by the actuator, said upper and lower carriages being vertically opposed to each other;
• a pair of upper and lower reading/writing heads respectively disposed on opposed faces of said upper and lower carriages, said heads being respectively contacted from upper and lower sides with magnetic data recording surfaces of a removable magnetic data recording medium by a predetermined load pressure, to read and write data;
• projections respectively disposed on said opposed faces of said pair of upper and lower carriages, said projections being opposed to each other and formed integrally with said pair of upper and lower carriages;
• a carriage opening/closing member, having slopes of a rising gradient and a falling gradient, arranged in a space which is between said pair of upper and lower carriages and behind said projections, said slopes respectively allowing, when said movable member is separated from a zero track position of the magnetic data recording medium to be further moved toward a radial outside, said upper projection to be obliquely upward moved in a sliding manner, and said lower projection to be obliquely downward moved in a sliding manner,
• where said pair of upper and lower reading/writing heads are respectively separated from the magnetic data recording surfaces by overriding of said projections over said slopes and sliding movements of said projections.