Magnetic friction couplings

Claim 1

A DRIVE TRANSMISSION ASSEMBLY HAVING, IN COMBINATION, A CASING RING HAVING AN OUTER END ADAPTED FOR RIGID ABUTMENT WITH AND BOLTING DETACHABLY TO A SUPPORT, A CYLINDRICAL PILOT SURFACE FORMED AROUND THE OTHER END OF SAID RING CONCENTRIC WITH THE RING AXIS, A SECOND CASING RING IN THE FORM OF A CUP, A SECOND CYLINDRICAL PILOT SURFACE AROUND THE CUP LIP TELESCOPED CLOSELY WITH SAID FIRST SURFACE AND HOLDING THE RINGS POSITIVELY IN PRECISE ALINEMENT, MEANS DETACHABLY CLAMPING SAID RINGS TOGETHER WITH SAID OUTER END AND SAID CUP LIP IN RIGID ABUTMENT, A ROTARY INPUT SHAFT DISPOSED IN A FIXED AXIAL POSITION IN SAID FIRST CASING RING, A MAGNETIC FRICTION CLUTCH HOUSED WITHIN THE UNITARY CASING DEFINED BY SAID RINGS INCLUDING DRIVING AND DRIVEN FRICTION RINGS HAVING OPPOSED FACES AND A MAGNET WINDING MOUNTED WITHIN SAID FIRST CASING RING AND SELECTIVELY ENERGIZABLE TO CONTROL THE AXIAL GRIPPING ENGAGEMENT OF SAID FRICTION RINGS, MEANS MOUNTING SAID DRIVING FRICTION RING ON SAID SHAFT IN A POSITION AXIALLY FIXED RELATIVE TO SAID FIRST CASING RING, AN OUTPUT SHAFT EXTENDING THROUGH AND JOURNALED INTERMEDIATE ITS ENDS IN THE BOTTOM OF SAID CUP, AND MEANS ON THE INNER ENDS OF SAID OUTPUT SHAFT SUPPORTING SAID DRIVEN FRICTION RING FOR MOVEMENT AXIALLY ALONG THE SHAFT INTO GRIPPING ENGAGEMENT WITH SAID DRIVING RING WHILE PROVIDING A FRICTION RESISTING MOVEMENT OF THE DRIVEN RING ALONG THE OUTPUT SHAFT WITH A FORCE WHICH IS LESS THAN THE ATTRACTIVE FORCE EXERTED ON THE DRIVEN RING BY SAID MAGNET WHEN ACTIVATED BUT WHICH IS SUFFICIENT TO MAINTAIN THE AXIAL POSITION OF THE DRIVEN RING WHEN SAID MAGNET IS INACTIVE.