Electric cooking apparatus having thermomagnetic temperature control means

Claim 1

A COOKING APPARATUS HAVING A HEATER CIRCUIT WHICH IS INSTANTANEOUSLY CUT OFF BY AN ABRUPT TEMPERATURE RISE IN THE APPARATUS, COMPRISING A VESSEL FOR CONTAINING THE FOOD TO BE COOKED, A HEATING PLATE HAVING HEATER MEANS FOR HEATING SAID VESSEL, SWITCHING MEANS FOR ENERGIZING AND DEENERGIZING SAID HEATER MEANS, A HEAT-ACTUATED DEVICE ADAPTED TO OPERATE IN RESPONSE TO AN ABRUPT TEMPERATURE RISE IN SAID VESSEL, SAID HEAT-ACTUATED DEVICE COMPRISING AT LEAST ONE SUBSTANTIALLY RECTANGULAR FERRITE ELEMENT ABUTTING SAID VESSEL THROUGH A HEAT-CONDUCTIVE PLATE, SAID FERRITE ELEMENT HAVING A CURIE POINT IN THE VICINITY OF THE ABRUPT TEMPERATURE RISE IN SAID VESSEL, AT LEAST ONE SUBSTANTIALLY RECTANGULAR PERMANENT MAGNET DISPOSED OPPOSITE EACH SAID FERRITE ELEMENT AND ADAPTED TO BE MOVED RELATIVE TO SAID ELEMENT, SPRING MEANS DISPOSED BETWEEN SAID FERRITE ELEMENT AND SAID PERMANENT MAGNET, SAID SPRING MEANS HAVING A RESILIENT FORCE WHICH IS WEAKER THAN THE ATTRACTING FORCE BETWEEN THE FERRITE ELEMENT AND THE PERMANENT MAGNET AT TEMPERATURES BELOW THE CURIE POINT BUT BEING SUFFICIENT TO MOVE THEM APART WHEN THE TEMPERATURE OF SAID VESSEL APPROACHES THE CURIE POINT OF THE FERRITE ELEMENT, SAID HEAT-ACTUATED DEVICE BEING FURTHER PROVIDED WITH MEANS TO VARY THE AMOUNT OF THE SURFACE AREA OF SAID FERRITE ELEMENT AND PERMANENT MAGNET IN OPPOSITION TO EACH OTHER TO THEREBY ADJUST THE ATTRACTIVE FORCES BETWEEN THE FERRITE ELEMENT AND MAGNET AND THUS THE OPERATING TEMPERATURE OF THE SWITCHING MEANS, SAID MEANS TO VARY THE OPPOSING AREAS OF THE FERRITE ELEMENT AND THE PERMANENT MAGNET COMPRISING A SUBSTANTIALLY CYLINDRICAL CASING, THE UPPER END OF WHICH IS ATTACHED TO SAID HEAT-CONDUCTING PLATE AND WHICH HAS TEETH FORMED ABOUT AN OPENING AT ITS BOTTOM END, A PLATE ROTATABLY AND AXIALLY MOVABLY MOUNTED WITHIN SAID CYLINDRICAL CASING AND HAVING SAID PERMANENT MAGNET SECURED THEREON, AN ADJUSTING PLATE LOOSELY ROTATABLY COUPLED TO THE OUTER FACE OF THE BOTTOM OF THE CASING AND CONNECTED TO THE MOVABLE PLATE FOR ROTATION THEREWITH, SAID ADJUSTING PLATE BEING PROVIDED WITH GEAR MEANS IN OPERABLE ENGAGEMENT WITH THE TEETH OF SAID CASING TO THEREBY ROTATE SAID MOVABLE PLATE, MEANS CONNECTED TO SAID PERMANENT MAGNET TO ACTUATE SAID SWITCHING MEANS.