Self regulating temperature heater with thermally conductive extensions

Abstract

Spaced contact pads (23,43,83,84) on a printed circuit board (19,45,85) are soldered to respective spaced contacts (21,41,51,81,82) in a cable (230,50) or connector assembly (40,80) by means of respective spaced connecting members (15,48,57,70,92,94,96,98,100,102,104,106) interposed between contacts to be soldered. The connecting members are typically electrically and thermally conductive finger-like projections formed as part of a heater body (10,60,55,47,91) and are readily severably from the heater body after soldering to thereby remain part of the final solder connection. A presecribed amount of fusible material (e.g., solder) is pre-deposited on the connecting members and/or contacts and is melted when the heater is actuated. The heater body may be a self-regulating heater in the form of a copper substrate (11,61,65) having a thin surface layer (13, 63,67) of magnetically permeable, high resistance alloy. An alternating current of constant amplitude and high frequency is passed through the heater body and is concentrated in the surface layer at temperatures below the surface layer Curie temperature. At higher temperatures the current is distributed through the lower resistance substrate to limit further heating. During the time interval required for the surface layer to reach its Curie temperature, the resistive power dissipation creates sufficient thermal energy to melt the pre-deposited solder. The connecting members are positioned and configured as necessary to reach their respective connection sites.