In a magnetic tape cassette recorder-player having a tape drive and recorder-player heads capable of operation in either direction and equipped with autoreverse means for operation at one end of the tape in a cassette, apparatus for providing a set of cassettes for recording or for playing in automatic succession comprising:
- a rotary cassette transport turnstile unit in the form of a compartmented unit of cylindrical contour having a wheel member (20) providing a continuous circular periphery at its edge on which member there are supported, radially inwards of said periphery, two perpendicular sets of parallel partition walls defining the edge boundaries of four cassette compartments each open towards said wheel member periphery, first and second partition walls of each said set (22-1, 22-3;
- 22-2, 22-4) each serving to separate one of the longer sides of one of said compartments from one of the shorter sides of an adjacent compartment and also together enclosing, by virtue of the difference between the length and width of the cassettes for which said compartments and dimensioned, a central cavity (42) centered on the axis of said wheel member which is open in at least one axial direction, and third partition walls of each said set (24-1, 24-3;
- 24-2, 24-4) respectively serving to define a third boundary wall of each compartment which is the most remote of that compartment's boundary walls from the axis of said wheel member, said magazine also having on its periphery index catch means (30) for fixing four positions of said turnstile at intervals of 90.degree. of rotation;
- a stationary socket unit fitting said turnstile unit and having an enclosing rim for closely and concentrically surounding said wheel member of said turnstile unit and the cassette compartments supported on said wheel member except for a single large opening in said rim of a size sufficient for passage of a cassette directly out of the open side of one of said compartments, said rim also having an aperture for access to said index catch means of said turnstile unit, said stationary socket unit also having a pivot-defining projection for fitting into said central cavity of said turnstile unit and further providing an aperture for relative movement of a cassette and tape drive into and out of a compartment of said turnstile unit which is located in an operating position defined by said stationary socket unit;
- turnstile drive means (50) mounted on said stationary socket for driving said turnstile unit stepwise in 90.degree. increments of rotation with stops between said rotation increments and for controllably ejecting a cassette inserting a cassette through said aperture of said rim of said stationary socket unit during a stop of said turnstile unit rotation, and
- indexing means coordinated with said drive means (50) and said index catch means (30) for arresting and stepwise 90.degree. increments of rotation at a position permitting recording or playing operation with a cassette in one compartment of said turnstile unit and ejection of insertion of a cassette from or into another compartment of said turnstile unit.