Double-pendulum vibration isolator with three-dimensional isolation

This isolator is an improved version of one that was described recently in this journal. It consists of a platform suspended by three springs, the damping being provided by a much smaller mass, suspended from the platform by a spring and damped in an oil bath. This simple device is a highly effective isolator, with a weak resonance peak and a transmissibility that decreases as 1/f(2), both horizontally and vertically. None of the parameters are critical.