Improvements relating to thermostatically-controlled electric immersion heaters

摘要

1,097,193. Thermal switches. D. H. HADEN. Sept. 5, 1966 [Sept. 18, 1965], No. 39884/65. Heading H2B. An electric immersion heater of the kind comprising a sheathed heating element I mounted in a head 4 intended to be mounted in the wall of a veseel such as an electric kettle has a concave-convex bi-metallic disc 17 located within a recess 18 in the inside of the base 3 of head 4 and operatively connected to a switch 9 carried by the end closure member 6 of head 4, the disc 17, when a given temperature is reached, being deflected over dead-centre with a snap-action to open, or allow to open, the switch. As shown, the movement of disc 17 is transmitted by rod 20 to resilient blade 9 carrying movable contact 10 engaging fixed contact 11. In an alternative embodiment, Fig. 8 (not shown), in the unoperated condition disc 17 has its convex side facing the contacts and holds the contacts closed against the resilience of blade 9 which opens the contacts when allowed to do so by disc 17 snapping over.