Temperature-responsive clutch or brake

Claim 1

A ROTARY FORCE COUPLING COMPRISING IN COMBINATION A PAIR OF RELATIVELY ROTATABLE ELEMENTS TO BE COUPLED CARRIED BY SUPPORTS SPACED A FIXED DISTANCE APART, SAID PAIR OF RELATIVELY ROTATABLE ELEMENTS BEING DISPOSED ADJACENT ONE ANOTHER IN A COMMON MAGNETIC FLUX PATH, A PERMANENT MAGNET AND A SUBSTANCE HAVING A CURIE POINT WHICH DISPLAYS, AT TEMPERATURES BELOW SAID CURIE POINT, A CHANGE IN PERMEABILITY ACCOMPANYING A FIRST-ORDER TRANSITION FROM A FIRST SOLID STATE PHASE TO A SECOND SOLID STATE PHASE AT A GIVE TEMPERATURE, BOTH SAID PERMANENT MAGNET AND SAID SUBSTANCE BEING PERMANENTLY DISPOSED IN SAID COMMON MAGNETIC FLUX PATH, SAID PERMANENT MAGNET AND SAID SUBSTANCE TOGETHER COMPLETING A MAGNETIC FLUX CIRCUIT BETWEEN SAID ELEMENTS OF SAID PAIR COUPLING ONE OF SAID ELEMENTS WITH THE OTHER OF SAID ELEMENTS DURING THE TIME THAT SAID SUBSTANCE EXISTS IN SAID FIRST SOLID STATE PHASE AND UNCOUPLING SAID ELEMENTS OF SAID PAIR WHEN SAID SUBSTANCE EXISTS IN SAID SECOND SOLID STATE PHASE.