Patent ID: 7335107

Claim:
A torsional coupling, comprising: a body having a circumference and defining a center axis, the body being rotatable about the center axis; a ring including an inner diameter disposed about the circumference, the inner diameter including a keyway having a ring contact surface defining a first radius, the ring being configured to rotate about the center axis; and a coupling element associated with the body and being configured to apply a centrifugal force radially outwardly from the circumference of the body when the body rotates, wherein the coupling element includes a coupling element contact surface having a second radius substantially different than the first radius of the ring contact surface, the coupling element contact surface being in contact with the ring contact surface and being configured to apply the force against the ring contact surface to rotate the ring relative to the body and wherein the effective stiffness of the torsional coupling increases as the rotational speed of the body increases.