Thermal timing apparatus

Claim 1

A VOLTAGE-COMPENSATED THERMAL TIME DELAY SWITCH COMPRISING IN COMBINATION: A FIRST BIMETAL MEMBER HAVING A SUBSTANTIALLY UNIFORM DEFLECTION-TEMPERATURE CURVE; A SECOND BIMETAL MEMBER HAVING A DEFLECTION-TEMPERATURE CURVE THAT REVERSES AT A PREDETERMINED TEMPERATURE; ELECTRIC HEATING MEANS MOUNTED IN HEAT TRANSFER RELATION WITH SAID MEMBERS TO CAUSE SAID MEMBERS TO MOVE UPON BEING HEATED; SWITCH CONTACTS MECHANICALLY CONNECTED WITH SAID MEMBERS AND OPERATED THEREBY IN A GIVEN PREDETERMINED TIME INTERVAL IN RESPONSE TO ENERGIZATION OF SAID HEATING MEANS; SAID FIRST AND SECOND MEMBERS BEING DISPOSED TO DEFLECT IN OPPOSITE DIRECTIONS WITH AN INCREASE IN TEMPERATURE OF SAID MEMBERS WHEN THE TEMPERATURE OF SAID SECOND MEMBER IS BELOW SAID PREDETERMINED VALUE; SAID FIRST AND SECOND MEMBERS BEING DISPOSED TO DEFLECT IN THE SAME DIRECTION WITH AN INCREASE IN TEMPERATURE WHEN THE TEMPERATURE OF SAID SECOND MEMBER IS ABOVE SAID PREDETERMINED VALUE; SAID HEATING MEANS BEING EFFECTIVE TO HEAT SAID SECOND MEMBER TO A TEMPERATURE ABOVE SAID PREDETERMINED VALUE IN SAID GIVEN TIME INTERVAL WHEN A VOLTAGE IS APPLIED TO SAID HEATING MEANS HAVING MAGNITUDE GREATER THAN A FIRST SELECTED VALUE; SAID FIRST AND SECOND MEMBERS BEING EFFECTIVE TO OPERATE SAID CONTACTS ONLY WHEN SAID SECOND MEMBER IS HEATED TO A TEMPERRATURE EXCEEDING SAID PREDETERMINED VALUE; AND SAID MEMBERS BEING RESPONSIVE TO VARIATIONS IN THE HEATING RATE OF SAID HEATING MEANS TO MAINTAIN SUBSTANTIALLY CONSTANT THE TIME INTERVAL IN WHICH SAID OPERATION OF SAID SWITCH CONTACTS OCCURS DURING VARIATIONS IN THE MAGNITUDE OF THE VOLTAGE APPLIED TO SAID HEATING MEANS BETWEEN SAID FIRST SELECTED VALUE AND A SECOND SELECTED VALUE GREATER THAN SAID FIRST SELECTED VALUE.