Vibration isolation system

DETAILED DESCRIPTION Briefly, and in general terms, the present invention provides a versatile vibration isolation system that exhibits low stiffness, which can be made as low as zero or near zero, both vertically and horizontally, to provide vibration isolation capabilities in all directions.
The system offers a substantial improvement over most current state-of-the-art isolation systems in reducing transmission of vibrations to sensitive instruments and equipment, particularly those vibrations with very low frequencies and very small amplitudes.
The system is capable of isolating vibrations below one Hertz while still effectively isolating vibrations as high as 100 Hertz.
The vibration isolation system of the present invention utilizes various configurations of elastic structures that can be loaded to approach a point of elastic instability.
The elastic instability associated with each configuration has an instability mode shape or buckling mode into which the structure deforms as it goes unstable or buckles.
Right at the instability point, where the load causing the instability is right at the so-called "critical buckling load", the structure can be given a small deflection into the buckled shape with essentially zero resisting force, or zero spring rate.
If the instability-producing load is slightly below the critical buckling load, the structure can be given a small deflection into the instability mode shape with very little resisting force thereby exhibiting very low stiffness.
The magnitude of the stiffness depends on how closely the instability point is approached.
It is this principle that is used in the present invention to create zero or near-zero stiffness.
If the load causing the instability is greater than the critical buckling load, then as the structure deforms into the buckled shape, the excess load will tend to propel the structure into the buckled shape creating a negative-stiffness or negative-spring-rate mechanism.
A common example is the "snap-through" or "over-center" mechanism