Variable heat transfer device

DETAILED DESCRIPTION The general purpose of this invention is to provide a variable heat transfer device, or thermal switch, having a relatively high gain.
That is, the invention exhibits a relatively large change in thermal conductance in response to a sensed change in temperature.
Thus, the present invention provides a flexible strip of heat conducting material disposed to conduct heat from one heat station to another heat station.
The contact made between the strip of heat conducting material and at least one heat station is subjected to a variable contact pressure.
High gain is achieved, in part, because a relatively large change in this contact pressure is produced by a relatively small change in the temperature of an actuator.
The actuator comprises a heat expandable material which drives a piston against the strip of heat conducting material.
A relatively small displacement of the actuator and piston causes a large change in contact pressure.
In addition, the achievement of relatively large heat conductance for relatively low contact pressures is obtained through the use of low yield strength metals on flat polished surfaces at the contact interface.
As another feature of the invention contributing to its high gain, the flexible strip of heat conducting material is fabricated to be non-resilient.