Multiple friction clutches

Claim 1

IN A FRICTION CLUTCH; A FIRST CLUTCH DISC, A PRESSURE RING ON ONE SIDE OF SAID FIRST DISC AND AN AXIALLY MOVABLE PRESSURE PLATE ON THE OPPOSITE SIDE THEREOF, A FIRST PLATE SPRING HAVING A DECLINING CHARACTERISTIC CURVE AND URGING SAID PRESSURE PLATE TOWARD SAID PRESSURE RING TO GRIP SAID FIRST DISC THEREBETWEEN, CONTROL MEANS INTERPOSED BETWEEN SAID FIRST SPRING AND SAID FIRST PRESSURE PLATE AT THE INNER PERIPHERY THEREOF, SAID MEANS COMPRISING A CAM MECHANISM OPERABLE IN RESPONSE TO SLIPPING OF SAID FIRST DISC ON ITS PRESSURE RING TO VARY THE THRUST OF SAID SPRING TO MAINTAIN THE PRODUCT OF THE TENSION OF SAID FIRST SPRING AND THE SLIPPING OF SAID FIRST CLUTCH DISC WITHIN PREDETERMINED LIMITS, A SECOND CLUTCH DISC, A SECOND PRESSURE RING ON ONE SIDE OF SAID SECOND DISC AND A SECOND PRESSURE PLATE ON THE OTHER SIDE THEREOF, A SECOND SPRING BIASING SAID SECOND PRESSURE PLATE TOWARD SAID SECOND PRESSURE RING, A HOUSING TO WHICH SAID PRESSURE RINGS ARE RIGIDLY CONNECTED TO FORM A UNIT, AND CLUTCH ACTUATING MEANS ON SAID UNIT FOR MOVING SAID PRESSURE PLATES SIMULTANEOUSLY OR SEQUENTIALLY AWAY FROM THEIR RESPECTIVE DISCS TO INTERRUPT THE TRANSMISSION OF TORQUE INTO SAID DISCS.