Cartridge drive apparatus

Claim 1

A compact apparatus for driving a cartridge mounted rotatable capstan and take-up reel to enable a ribbon to be transported by said capstan from a cartridge mounted supply reel and snugly accommodated on said take-up reel, said apparatus comprising: a pair of spaced upper and lower support members; a drive motor carried by one of said support members and having an output shaft provided with a driving gear; a capstan drive assembly for providing a direct driving force to said capstan and a releasable driving force to said take-up reel, said capstan drive assembly including: an input gear having an elongate central body portion rotatably secured at opposite ends thereof to said upper and said lower support members and a toothed periphery engaged with said motor driving gear, said central body portion having a central bore provided with a pair of oppositely disposed slotted walls axially extending from the end of said bore adjacent said upper support member toward the other end of said bore and terminating at an intermediate axial location, a capstan drive key received within said bore, said key having an upper end and a lower end and a pair of oppositely extending tab portions located at said upper end each slideably received by a different one of said slotted walls to permit axial translation of said key, rotation of said input gear being transmitted to said tab portions of said key by said slotted walls, means for biasing said key toward said upper support member, limit stop means secured to said key adjacent the lower end thereof for limiting axial translation of said key in the direction of said upper support member, an output gear having an elongate central body portion with a central bore slidably received on the outer surface of said central body portion of said input gear to permit relative rotation therebetween, said output gear having a toothed outer periphery located adjacent and below said upper support member, and a magnetic clutch assembly for providing a releasable driving force to said output gear from said input gear, said magnetic clutch assembly including a magnetic drive ring secured to said input gear and having a toothed inner peripheral surface, a pair of magnetic members mechanically linked to said central body portion of said output gear, each said magnetic member having a toothed outer peripheral surface positioned adjacent said inner peripheral surface of said magnetic drive ring, and a magnet positioned between said pair of magnetic members for providing magnetic flux linking said pair of magnetic members with said magnetic drive ring; and a reel drive assembly rotatably carried by said support members and driven by said output gear; said magnetic clutch providing a releasable driving force for said output gear whenever the tension in the ribbon between said capstan and said reel lies below a predetermined threshold value.