Pilot operated friction clutch

Claim 1

A FRICTION COUPLING HAVING, IN COMBINATION, TWO MEMBERS DISPOSED END TO END AND MOUNTED FOR RELATIVE TURNING ABOUT A COMMON AXIS, ANNULAR FRICTION SURFACES ON THE RESPECTIVE MEMBERS, ONE OF SAID MEMBERS BEING A DRIVER, A FREE FLOATING FICTION BEND EXTENDING AROUND SAID SURFACES FOR FREE TURNING RELATIVE THERETO, SAID BAND BEING SPLIT AND CHANGEABLE IN DIAMETER TO GRIP SAID SURFACES FRICTIONALLY AND THEREBY TRANSMIT TORQUE FROM THE DRIVING MEMBER TO THE OTHER MEMBER, A THIRD ANNULAR SURFACE RIGID WITH SAID DRIVER AND DISPOSED ADJACENT THE SIDE OF THE BAND AND EXTENDING AXIALLY THEREFROM BUT OUTWARDLY BEYOND THE LATTER, A MULTIPLE TURN HELICAL COIL LOOSELY TELESCOPED WITH SAID BAND AND SAID THIRD SURFACE AND NORMALLY OUT OF CLUTCHING ENGAGEMENT THEREWITH, MEANS ANCHORING ONE DND OF SAID COIL TO ONE OF SAID MEMBERS, THE TURN AT THE OTHER END OF TH COIL BEING FREE AND EXTENDING AROUND SAID THIRD SURFACE FOR GRIPPING ENGAGEMENT THEREWITH, A PILOT FRICTION CLUTCH OPERABLE WHEN ACTIVATED TO DERIVE A TORQUE FROM THE TURNING OF SAID DRIVING MEMBER AND APPLY SUCH TORQUE TO OPPOSITE ENDS OF SAID COIL TO CHANGE THE DIAMETER OF THE COIL IN A DIRECTION TO COMPRESS SAID BAND AGAINST SAID FIRST TWO SURFACES, SAID COIL PROJECTING ALONG SAID DRIVING MEMBER BEYOND THE EDGE OF SAID BAND WITH SAID FREE TURN OVERLAPPING SAID THIRD SURFACE, AND AN ARCUATE FREE FLOATING AND RADIALLY EXPANSIBLE AND CONTRACTIBLE FRICTION MEMBER DISPOSED ALONGSIDE SAID BAND BETWEEN SAID THIRD SURFACE AND SAID FREE END TURN OF SAID COIL SO AS TO BE COMPRESSED BETWEEN SUCH SURFACE AND END TURN DURING COMPRESSION OF SAID BAND BY THE COIL AND THEREBY DERIVE A SECONDARY FRICTION TORQUE AUGMENTING THE TORQUE OF SAID PILOT CLUTCH IN CHANGING THE DIAMETER OF SAID COIL.