TSC - Combined Steel & Rubber Spring Unit Isolators

Type TSC T15

A major advance in design has successfully combined the best characteristics of steel springs and rubber springs to produce an efficient, compact and economical range of unit isolators suitable for many types of applications. TSC unit isolators are highly effective in reducing the transmission of vibration, structure-borne noise and shock from a wide range of rotating and reciprocating machinery and in protecting sensitive apparatus from external disturbances. They are particularly suitable for marine and mobile applications as internal snubbers are incorporated to control movement of the isolated machine. Testing of TSC T15 isolators has shown vertical isolation efficiencies in excess of ninety-five percent at primary operating speeds of fifteen hundred rpm and above.



  • Helical steel spring to BS1726 Class B.
  • Inclined rubber moulding manufactured from are first grade natural rubber.
  • SG iron top casting to BS EN 1563 EN-GJS-400/15.
  • High strength steel base housing.
  • Steel spring is isolated from the base by integrated natural rubber reducing transmission of high frequency vibration and effectively damping spring coil surge resonance.
  • Springs are pre-compressed on assembly which resulting in high equivalent static deflection and load capacity with minimum change between loaded and unloaded height.
  • Rubber spring elements are effectively protected by the top casting and its extended skirt.
  • Both types of spring support a proportion of the total load and thus the overall rate of creep is much reduced compared to an equivalent all-rubber unit isolator.
  • A selection of steel and rubber springs that each having different vertical and lateral stiffness closely controlled in manufacture.

Typical Applications

  • Marine Propulsion Engines.
  • Marine Generator Sets

Application Notes

  • All values of stiffness are nominal subject to ±20% variation on final assembly. The isolator rubber elements are pre-loaded 1.5 mm upon assembly.
  • Stiffness is linear over working load range.
  • Dynamic stiffness may vary with frequency. Values stated are reliable for calculation of low frequency characteristics below 100 Hz.
  • Optimum system stiffness characteristics can be achieved by careful orientation of individual isolators.
  • All connections to and from isolated machine must include flexible lengths, not only to prevent transmission of vibration through the connections and allow the system freedom of movement, but also to avoid possible failure of the connections.
  • Analysis of the isolated system is normally undertaken by Christie & Grey to predict the response to ship motion, machine forces and shocks to enable the correct selection of flexible connections.