A sealed extensible bellows containing freon and a flexible wick provide a heat pipe, and fixed end of which is attached to a heat sink (a cold body), the other movable end of the bellows carries a thermally conductive plate that moves from a nonengaging relationship to an engaging relationship with...http://www.google.se/patents/US3957107?utm_source=gb-gplus-sharePatent US3957107 - Thermal switch
