Abstract: An accurate, setting-protected, temperature controlled soldering iron has a control circuit including a non-adjustable replaceable resistor mounted near the junction of the handle and the tube which holds the soldering tip. When it is desired to change the temperature of the soldering tip, the handle must be disassembled from the tube to replace the non-adjustable resistor. Very accurate control of temperature at the soldering tip is maintained by the utilization of different laser trimmed resistors having extremely accurate resistances. A window is provided in the soldering handle to observe a number associated with the value of the non-adjustable replaceable resistor.

Abstract: A temperature probe using a first thermocouple junction at the end of a metal tip for measuring the temperature of an object is also provided with a second thermocouple junction on the metal tip at a predetermined distance from the first thermocouple for detecting heat flow in the tip from the first thermocouple toward the second thermocouple. Electronics responsive to both themocouples drive a heater which maintains the second thermocouple at substantially the same temperature as the first thermocouple, thereby to eliminate heat loading by the probe on the object being measured. A single adjustable resistance temperature detector electronically connected in series with the metal tip is used to calibrate the probe and compensate for errors in the temperature readings of the first and second thermocouples. The resistance temperature detector is made up of a wire located in the handle of the probe and is adjusted by stretching the wire to reduce its diameter and bulk resistance.

Abstract: A soldering or de-soldering tool with self-locking, removeable soldering or de-soldering tapered tips which interlock with a similar taper in a tip-receiving bore of the tool. The invention also is directed to a replaceable soldering or de-soldering tip using only a self-locking taper to provide attachment, sealing and heat transfer. The tips may be made of conventional materials, such as copper, or can be carbon-based. In the preferred embodiment of the invention the tips are carbon-based, and the attachment portion of the tip which fits within the tip-receiving bore of the tool is unplated.

Abstract: A soldering or de-soldering tip and method of manufacturing a soldering or de-soldering tip which has a carbon-based body with an attachment portion, an intermediate portion adjoining the attachment portion, and a solder-wetting portion adjoining the intermediate portion. The solder-wetting portion has an exterior coating of iron to provide a wettable working surface, and the intermediate portion has an exterior coating of chrome for localizing the wettable working surface and impeding the upward flow of solder along the intermediate portion and toward the attachment portion. The carbon-based body eliminates premature failure problems caused by the pitting and oxidation of standard copper-based tips.

Abstract: The apparatus may be used to control heater elements for an over chamber. The heater elements are operated in accordance with the output of a comparator having on one input a voltage representative of the temperature in a chamber. The voltage on the other input is established in accordance with the desired or ultimate temperature in the chamber. As long as the volage on the second-mentioned input is greater than the voltage on the other input, the heater elements will be energized to heat the chamber. The voltage on the second-mentioned input is modulated with a triangular wave so that the heater elements are operated intermittently as the desired temperature of the chamber is approached. The amplitude of the triangular wave varies with the desired temperature so that at higher and higher oven temperatures, the heater elements start to become intermittent at higher and higher temperatures.