Thermal responsive circuit breaking relay

Claim 1

IN CIRCUIT-BREAKING APPARATUS FOR AN ELECTRICAL LOAD ADAPTED TO BE ENERGIZED FROM A SOURCE OF ELECTRICAL POWER, A DIFFERENTIAL RELAY HAVING A RELAY ARMATURE ASSOCIATED IN A MAGNETIC CIRCUIT WITH A MAIN RELAY COIL AND A BUCKING RELAY WINDING, SAID COIL AND WINDING BEING PARALLEL-CONNECTED ACROSS SAID POWER SOURCE AND ADAPTED TO PRODUCE OPPOSING MAGNETIC FIELDS IN SAID MAGNETIC CIRCUIT, CONNECTED ACROSS SAID POWER SOURCE WHEREBY THE RESPECTIVE CURRENTS TRAVERSING SAID RELAY COIL AND RELAY WINDING ARE INDEPENDENT OF SAID LOAD CURRENT, SAID ARMATURE ADAPTED TO BE ACTUATED WHEN THE COMPOSITE FLUX PRODUCED BY SAID COIL AND WINDING IN SAID MAGNETIC CIRCUIT EXCEEDS A PRESELECTED VALUE, A RESISTANCE COMPRISING A THERMISTOR SERIALLY CONNECTED BETWEEN SAID BUCKING RELAY WINDING AND SAID SOURCE OF ELECTRICAL POWER, SWITCH MEANS OPERABLE BY SAID ARMATURE BETWEEN A FIRST POSITION WHEN SAID ARMATURE IS DEACTUATED AND A SECOND POSITION WHEN ARMATURE IS ACTUATED, SAID SWITCH MEANS ADAPTED WHEN IN SAID SECOND POSITION TO DEENERGIZE SAID ELECTRICAL LOAD, AND SAID THERMISTOR BEING IN HEAT-EXCHANGE RELATIONSHIP WITH SAID ELECTRICAL LOAD WHEREBY UPON A PREDETERMINED CHANGE IN SAID RESISTANCE IN SERIES WITH SAID BUCKING WINDING THE COMPOSITE FLUX IN SAID MAGNETIC CIRCUIT IS INCREASED ABOVE SAID PRESELECTED VALUE THEREBY MOVING SAID SWITCH MEANS TO ITS SECOND POSITION TO DEENERGIZE SAID ELECTRICAL LOAD.