Rotating switch

The control knob (10) may be turned to a position marked by symbols (P,O,Auto) etc. on a calibrated surrounding ring (12). It may be pulled outward axially to make electrical contact and lock in position using two diametrically-opposed cam surfaces on the knob. The cam surfaces may engage in slots in an inner ring on the underside of the calibrated surrounding ring. A bayonet lock may fasten the calibrated surrounding ring to an inner switch housing. The control knob may have a cruciform shaft on its underside operating the switch.