| 摘要 |
<p>Line disc which is pref. driven by a main drive motor has pref. a peripheral channel into which one edge of the tape seats, and pref. the other edge is engaged by an idler disc. Pref. the tape is biassed into contact with the discs by spinning loaded idler rolls. The tape may be a film or punch tape, and light may be beamed by a light pipe between the discs, through the tape and transmitted light may be picked up by a sensor. Pref. the tape carries reference signals which are compared with the programme signals supplied eg. to a circular knitting machine, and the compared signal may be used to control rotation of the tape supply or take-up spools. The drive mechanism is simple and accurate.</p> |
