Patent ID: 7902719
Filing Date: 2011-03-08
Classification: F16F

Abstract:
1. An apparatus comprising: a shaft being oriented about a longitudinal axis; a piezoelectric tubular member in a substantially osculatory coaxial relation with at least a portion of said shaft; and at least one electrical network coupled with said piezoelectric tubular member for switchingly completing at least one electrical path through said piezoelectric tubular member; said piezoelectric tubular member having a first stiffness when said at least one electrical path is completed; said piezoelectric tubular member having a second stiffness when said at least one electrical path is not completed; said piezoelectric tubular member being situated between said axis and said shaft; said piezoelectric tubular member being polarized; said at least one electrical network including a photoelectric switching element for effecting said switching completion and a light source for controlling said photoelectric switching element; said light source being situated remotely from said shaft aimed for selectively illuminating said photoelectric switching element; said at least one physical parameter including frequency of at least one vibrational mode of said shaft.