Magnetic tape cassette tape position indexing device - has markings carried by two coaxial discs of 2-stage reduction gear

摘要

The indexing device has a two-stage reduction gear driven by one of the cassette tape reels. The gear uses coaxial rings two of which carry index markings cooperating with an indicator fixed to the cassette. The first stage of the reduction gear uses a ring (127) with an eccentric periphery driven by one of the cassette reels to allow it to rotate within a circular ring (101) with peripheral teeth, in turn able to oscillate with play about a fixed point. The latter peripheral teeth engage those around the interior of a second circular ring (71). The second stage uses a third circular ring (51) with an internal surface (52) enclosing the second circular ring (71) and with external peripheral teeth engaging internal peripheral teeth of a surrounding fixed ring (31). Pref. the index markings are carried by the second and third circular rings (71,51).