Patent ID: 8490952

Claim:
Apparatus for isolating movement of a suspended mass, the apparatus comprising: a high pressure compressible fluid source for supplying compressible fluid under pressure when directed by a controller; a vacuum source for rapidly evacuating compressible fluid under pressure when directed by a controller; a compressible fluid spring for receiving high pressure compressible fluid from the high pressure compressible fluid source; a compressible fluid spring head at one end of the compressible fluid spring for attachment to a suspended mass being isolated from vibrations; a compressible fluid spring piston at another end of the compressible fluid spring for attachment to an un-sprung mass which is a mass generating the vibrations, the compressible fluid spring piston for causing the suspended mass and the un-sprung mass to be pushed apart when compressible fluid under pressure is allowed to enter the compressible fluid spring; whereby gravity and suspended mass weight cause the suspended mass and the un-sprung mass to move closer together when fluid is relieved in said compressible fluid spring; a relative position transducer coupled with said compressible fluid spring and configured for measuring a separation distance with respect to the suspended mass and generating a compressible fluid spring height control signal for actively controlling access of said compressible fluid spring to said vacuum source and said high pressure compressible fluid source; a variable volume accumulator in fluid communication with the compressible fluid spring for increasing an effective compressible fluid volume of the compressible fluid spring, thereby modifying the natural frequency of the compressible fluid spring; means for controlling a continuously variable flow rate of compressible fluid between the compressible fluid spring and the variable volume accumulator at a prescribed rate, thereby allowing the compressible fluid spring to operate with a variable damping ratio caused by variable velocity dependent resistive force; where said means for controlling comprises a controlled sharp-edged orifice configured for variable adjustments.