TMC Catalog

Laboratory Tables & TableTop PlatformsGimbal Piston IsolatorThe key element in allTMC vibration isolation tablesis our Gimbal Piston Air Isolator.These assemblies have repeatedlyproven, in independent tests, to provideoutstanding isolation in all directionsfor even the lowest input levels.The Gimbal Piston utilizes proprietarypneumatic damping techniques, whichinclude air flow restrictors and a uniquegeometry. It is lightly damped and highlyresponsive to typical, low-amplitudeambient floor vibrations, yet achievesvery high damping for gross transientdisturbances, such as sudden loadchanges or bumping the top plate. Theresult is that Gimbal Piston Isolatorsprovide superior isolation yet will virtuallyeliminate any gross disturbance withina few seconds.The Gimbal Piston can also stabilizeisolated systems with relatively highcenters of gravity without compromisingisolation.Low-AmplitudeInput ResponseThe greatest challenge in designingan effective isolator is to maintain goodperformance at the low vibration amplitudeinputs typical of ambient buildingfloor vibration. Isolator specificationsare often based on measurements donewith the isolator placed on a “shakertable” with very high amplitude inputlevels. Such testing, with input ampli -tudes on the order of millimeters,yields unreal istic performance expec -tations and is misleading as resultswill not reflect the actual performancein use.The Gimbal Piston Isolator design isunique in its ability to maintain its statedresonant frequency and high level ofattenuation in even the most quiet, real,floor environments. The performance islinear to such low amplitudes becausethe design is virtually free of frictionand therefore able to avoid rollingfriction to static friction transitions.Every other system that we have testedat levels typical for floor vibration ex hibitseither a higher resonant frequency thanclaimed or a substantial increase intransmission through the isolator mount.Vibration Isolation vs. Pneumatic Damping(source for theoretical curves:Harris & Crede, Shock and Vibration Handbook)Transmissibility = ( Acceleration Transmitted )Acceleration InputWe stress the importance of performancespecifications at low levels because wehave repeatedly observed, in our owntesting and in many as-used installations,that better performance is much easierto achieve at greater amplitudes andhigher frequencies.Transmissibility = ( Acceleration Transmitted )Acceleration Input1010.10.01Horizontal vs.Vertical Inputs1000%90%99%1 2 3 4 5 10 20 30 50 100Frequency, Hz■ Theoretical 1.5 Hz isolator with no damping■ Theoretical 1.5 Hz isolator with 0.2 dampingcoefficient■ Measured 63-500 Series Table with40-microinch floor inputs (vertical)1010.10.01Low-Amplitude Input Response1 2 3 4 5 10 20 30 50 100Frequency, Hz■ Measured 63-500 Series Table with40-microinch floor inputs (vertical)■ Measured 63-500 Series Table with4-microinch floor inputs (vertical)■ Measured 63-500 Series Table with0.1-microinch floor inputs (vertical)1000%90%99%Our innovative Isolator allows athin-wall, rolling diaphragm seal toaccommodate horizontal displacementIsolation AmplificationIsolation Amplification50 www.techmfg.com • 978-532-6330 • 800-542-9725 (Toll Free) • Fax: 978-531-8682 • sales@techmfg.com