Soldering Station: a Stand Whose Bimetal Switch Reads the Iron's Heat (Birk, Hart Mfg., US 2,248,486, 1941)

A soldering station: an ordinary electric iron plugs into its stand, and the stand controls it. When the iron is laid in the stand's trough, its heater housing sits over a flue with a U-shaped bimetal switch inside; the heat it gives off opens the switch at the temperature you set with a screw, and closes it again as it cools. A red lamp shows the iron heating, a green lamp shows it hot and idling. Result: a stand that keeps an electric iron at a set temperature between jobs and shows its state. Source: H. W. Birk (Hart Manufacturing), US 2,248,486 (1941). Unknown: sizes, the bimetal, the lamps. Picture: the patent drawing.