Tuned friction damper

Claim 1

A TORSIONAL VIBRATION DAMPER ASSEMBLY FOR MOUNTING IN OPERATIVE RELATION TO THE CRANKSHAFT OF AN INTERNAL COMBUSTION ENGINE COMPRISING A GENERALLY ANNULAR DRIVING MEMBER HAVING A RADIALLY INWARDLY EXTENDING SURFACE FOR CONCENTRIC ATTACHMENT TO A CRANKSHAFT AND HAVING A RADIALLY OUTWARDLY EXTENDING FLANGE, A DRIVEN INERTIA MEMBER MOUNTED CONCENTRICALLY OF SAID DRIVING MEMBER AND HAVING A CENTRAL APERTURE THEREIN ACCOMMODATING SAID DRIVING MEMBER, ELASTIC MEANS INTERPOSED BETWEEN SAID DRIVING AND DRIVEN MEMBERS PROHIBITING PERMANENT DISPLACEMENT OF THE DRIVEN MEMBER WITH RELATION TO THE DRIVING MEMBER AND WITH SAID ELASTIC MEANS STRESSED ONLY IN SHEAR UPON CYCLICAL DISPLACEMENT OF SAID DRIVEN MEMBER WITH RELATION TO SAID DRIVING MEMBER, SAID DRIVEN MEMBER BEING PROVIDED WITH A RADIALLY OUTWARDLY EXTENDING SLOT FREELY ACCOMMODATING SAID OUTWARDLY EXTENDING FLANGE OF SAID DRIVING MEMBER, AND MEANS FOR GENERATING A FRICTIONAL FORCE RESISTING RELATIVE MOTION BETWEEN SAID DRIVING AND DRIVEN MEMBERS INCLUDING A SERIES A SPACED FRICTION ELEMENTS CARRIED BY SAID OUTWARDLY EXTENDING FLANGE OF SAID DRIVING MEMBER, AND RESILIENT MEANS URGING SAID FRICTION ELEMENTS INTO FRICTIONAL ENGAGEMENT WITH THE DRIVEN ELEMENT SURFACES DEFINING SAID RADIALLY OUTWARDLY EXTENDING SLOT, WHEREBY TORSIONAL VIBRATIONS OF THE CRANKSHAFT ARE ABSORBED BY SAID ELASTIC MEANS AND BY SAID FRICTION ELEMENTS, SAID ELASTIC MEANS BEING SO SELECTED AS TO HAVE PHYSICAL PROPERTIES INSURING TUNING OF THE DAMPER TO A NATURAL FREQUENCY OF THE ENGINE CRANKSHAFT SYSTEM WHEREBY THE AMPLITUDE OF VIBRATIONAL MOTION BETWEEN SAID DRIVING AND DRIVEN MEMBERS IS RELATIVELY LARGE AND THE ENERGY ABSORBED BY SAID DAMPER IS CORRESPONDINGLY LARGE.