Tape cassette containing run counter disc

Claim 1

A counting mechanism for determining the number of times a length of tape is wound onto and then off of a reel including a hub rotatably mounted on a housing about which hub the tape is wound, and a flange projecting along a side surface of tape wound about the hub, said mechanism comprising a disc having spaced numbers positioned against and centered on the surface of the flange opposite the hub; means for frictionally driving said disc from said reel; first means adapted for engagement between said housing and said disc for preventing rotation of the disc in one direction while permitting rotation of the disc in the other direction; second means adapted for engagement between the housing and said disc at predetermined spaced locations related to the spacings between the numbers that, when engaged, will prevent rotation of the disc in the other direction; and third means adapted to be operated by the changing diameter of a coil of tape being wound onto and then off of the hub for disengaging said second means from one location and affording re-engagement of said second means at another location to cause incremental advance of the disc by said means for frictionally driving to change the location of the numbers relative to the housing.