I came across a Cartrivision rewinder in a surplus store once. It was a simple device, with a motor, some limit switches, a key switch, and a counter. The counter tracked how many cartridges had been rewound, for billing purposes.
Other bad ideas of that era: Polaroid once developed a VHS cartridge with a mechanical counter of how many times it had been played. After some number of plays, the tape jammed.
Other bad ideas of that era: Polaroid once developed a VHS cartridge with a mechanical counter of how many times it had been played. After some number of plays, the tape jammed.