Sliding code disc reader and detent therefor for dual pitch web feeding

摘要

A code reader, in the form of a photoelectric sensing device, is slidable across a coded disc which disc includes a first circle of apertures at one diameter designating a code channel for advancing record media, for example, at a spacing of six lines per inch and a second circle of apertures at another diameter designating a code channel for advancing the record media at a spacing of eight lines per inch. A positive locking detent is associated with the code reader for maintaining the desired position thereof for the selected code channel and line spacing.