Portable electrical heating unit with automatic cutoff
AssigneeCourtesy Interstate Corporation
InventorsDuane C. Remsnyder, Clarence C. Haynes
Life of this patent
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Abstract
A heating unit for heating the contents of a container includes an electrical circuit having a pressure responsive switch that is normally open and a thermally responsive switch that is normally closed, the pressure switch is responsive to a predetermined weight of the container on a pivotally mounted heating element for activating the switch to the closed position for activating the heating circuit. The thermal switch is responsive to an overheating of the unit to interrupt the circuit. The heating unit is provided with a heating element having a conical center portion surrounded by an annular flat or planar surface, for receiving containers having only a predetermined shaped bottom for accommodating the particular shape of the heating element.
Claims6
A portable electrical heating unit for heating a predetermined minimum quantity of material in a container, comprising:
- a stationary housing,
- an electrical heating element including an annular planar support surface surrounding an upwardly extending protrusion, for supporting a predetermined container,
- pivot means pivotally supporting said heating element on said housing,
- an electric circuit for connecting a source of electrical power to said heating element, said circuit including a weight responsive switch responsive to a predetermined minimum weight on said said support surface of said heating element for closing said switch, and a thermal switch in said circuit in series with said weight responsive switch and responsive to a predetermined temperature for interrupting said circuit,
- a counterweight pivotally mounted below said heating element and connected to oppose weight supported on said heating element, said weight responsive switch being positioned to be actuated by movement of said counterweight in opposition to said predetermined minimum weight on said heating element, and
- a container having a depression in the bottom for accommodating said upwardly extending protrusion.
Dependencies are inferred from the claim text.