KBK update for Wednesday, 11th March
RAFI have now scanned in for me the complete RAFI-System 72 (RC 72) catalogue. The catalogue was printed in 1983, which explains why the Hall sensor characteristics relate to later Siemens models (models seemingly not in existence when the switch series was introduced). The catalogue includes a diagram of the internal structure of both the Hall and mechanical types, and from this it is clear that this is indeed the annular-magnet type from the patent filed in 1972, which ties in with RAFI’s unclear indication that these switches were introduced in 1973. Jacob Alexander’s example will thus be a redesigned version. Two more switch types can now be seen: RC 72 N mains power switches, and keylock switches.
All we need now is details of RAFI’s original switches, which appear to have been magnetoresistive.