Abstract: An automatic thermal switch to control heat flow includes a first thermally conductive plate 2, a second thermally conductive plate 25 and a thermally conductive switch saddle 1 pivotally mounted to the first plate 2. A flexible heat carrier 27 is connected between the switch saddle 1 and the second plate 25. A phase-change power unit 9, including a piston 13 coupled to the switch saddle 1, is in thermal contact with the first thermally conductive plate 2. A biasing element 21 biases the switch saddle 1 in a predetermined position with respect to the first plate 2. When the phase-change power unit 9 is actuated by an increase in heat transmitted through the first plate 2, the piston 13 extends and causes the switch saddle 1 to pivot thereby varying the thermal conduction between the first and second plates 2 and 25 through the switch saddle 1 and flexible heat carrier 27.

Abstract: An automatic thermal switch to control heat flow includes a first thermally conductive plate, a second thermally conductive plate and a thermal transfer plate pivotally mounted between the first and second plates. A phase-change power unit, including a plunger connected to the transfer plate, is in thermal contact with the first thermally conductive plate. A biasing element, connected to the transfer plate, biases the transfer plate in a predetermined position with respect to the first and second plates. When the phase-change power unit is actuated by an increase in heat transmitted through the first plate, the plunger extends and pivots the transfer plate to vary the thermal conduction between the first and second plates through the transfer plate. The biasing element, transfer plate and piston can be arranged to provide either a normally closed or normally open thermally conductive path between the first and second plates.