Abstract: A data storage device has a pressurized flexible disc stack. An external actuator creates a partial split allowing a transducer to read edge codings on the discs to locate a desired one. An internal controller controls the pressure within the center of the stack and defines a zone aligned with the actuator within which the pressure is maintained above the bistable range while locating the desired disc. Upon locating the desired disc, the pressure with the zone is dropped below the upper limit of the bistable range causing the partial split to open or expand into a full, stable separation allowing a read/write head to access the desired disc.

Abstract: In a random access storage device a head transported relative to a rotating assembly of flexible disks and a pair of co-rotating end plates operates in clearance spaces formed by sliding the disks apart at a selected interface. One of the end plates is attached to a low friction spline which is quickly shiftable between predetermined axial limit positions. In the most confining position of this plate a single selected interface space between the disks is partially opened by deflection of the disks. The partial opening is sufficient to establish a pressure difference relative to the other interfaces but not enough for unobstructed entrance of the head. Shortly after formation of the partial opening the shiftable plate is actuated away from the disks in a quick movement.

Abstract: A flexible disk magnetic recording device wherein a large number of disks are separated by mechanical splitting means to form a space between any two selected disks for the insertion of a read/write transducing head. A restraint device is placed in bearing contact with the outer surface of the deflected portion of the disk stack at the periphery to create a bending moment in the deflected disks to buckle the disks. The restraint is placed at approximately 90 degrees subsequent to the splitting means in the direction of disk rotation, subtends an arc at the disk periphery of approximately 10.degree.-40.degree. and extends inwardly from the periphery one-half to two-thirds the radius.

Abstract: Multiple (e.g. 500) ultra-thin flexible storage disks are stacked in a closely spaced configuration between circular end plates and arranged for rotation together with the plates about a common axis. Recording surfaces of the rotating disks are deflected to successively expand (open) and contract (close) a selected interface and thereby provide recording access at the expanded interface. Separation of the selected interfacing surfaces for access is facilitated by maintaining a predetermined air pressure between the contracted disks which conditions the rotation of the disks to bistability in the contracted position. Thus only a small initiating force is required to expand any selected interface with the disks initially contracted. This reduces disk wear. Expansion of a selected interface is accelerated (for shortening access time) by applying vacuum to the disks in synchronism with the initiating force.