JPS5739073A - Soldering iron - Google Patents

Abstract

PURPOSE:To heat a soldering iron quickly at the start of its use by properly selectively using a main heating element of small wattage and an auxiliary heating element of large wattage having large positive temp. characteristics. CONSTITUTION:In the case of heating an iron tip 4 of low temp. to a working temp., a plug 22 is inserted into a receptacle, and a button 17 is pushed to close a switch 16. Then, electric power is supplied to both of a main heating element 11 and an auxiliary heating element 12, and since the resistance values of both elements 11, 12 are small at low temps., a large quantity of heat is generated. Hence, the temp. of the iron tip 4 rises sharply. Next, at the point of the time when the tip 4 seems to have attained an adequate temp., the switch 16 is opened. Thereafter, an approximately constant temp. is maintainted by the element 11 alone, and therefore soldering work is carried out in this state. When the temp. of the tip 4 lowers, again the switch 16 is closed to cause auxiliary heating with the element 12. At this time, the tip 4 and the element 12 are of elevated temps., and therefore the wattage of the element 12 is relatively small whereby overheating of the tip 4 is prevented.