Vibration isolation system with adjustable constant force, all-directional, attenuating seismic restraint

Abstract

A vibration isolation system includes a seismic restraint assembly that attenuates forces above a chosen magnitude transmitted to a unit from a support during a seismic event. Vertical friction elements on a vertical frame engage and support a vertical damper element. Horizontal friction elements on a horizontal frame engage and retain a horizontal damper element. One frame is connected to the unit, the other to the support. The vertical and horizontal damper elements interconnect, but lost motion spacing between these elements ordinarily prevents low level vibrations being communicated therethrough. Each of the vertical and horizontal friction elements is spring biased into a predetermined frictional engagement with its associated damper element. The force of the engagement is adjustable to adjust the level at which higher than ordinary forces that are being transmitted through the assembly will begin to be attenuated by slippage of the frictionally engaged elements.