S A F E T Y
MARSHMELLOW FABRICREINFORCED
RUBBER SPRINGS
In situations where access to air to inflate
the Airmounts is difficult, an attractive, nomaintenance
and silent alternative is provided by
Firestone’s MarshMellow springs.
MarshMellow springs appear similar to a solid
rubber mount. However, their unique construction
with fabric plies make the MarshMellow springs
much different in performance.
The fabric plies in MarshMellows provide the
springs with stability, higher load-carrying
capability as well as a constant cylindrical shape.
Solid rubber mounts of the same dimensions
carry less load and will deform with load and
time, because they do not have the fabric
reinforcement.
As with Airmounts, MarshMellow springs are a
variable spring rate device achieved by the fabric
reinforcement. The variable spring rate allows for
a nearly constant natural frequency over a range
of loads. This allows for changes in load without
significant change in isolation effectiveness.
MarshMellow springs are also able to endure
overload conditions of up to 40% deflection and
are also able to function well over a range of input
frequencies.
Due to their metal-free construction,
MarshMellow springs have been proven in damp
and corrosive environments where a standard coil
spring may fail. However, just as with Airmounts,
the environmental factors should be considered in
regard to this product.
MarshMellow springs reduce structurally
transmitted noise caused by vibration. They are
quiet, unlike steel springs which often chatter and
readily transmit high frequency structural noise.
Also, MarshMellow springs do not fail
catastrophically as coil springs do and continue to
offer some support even after failure. Coil springs
are prone to fatigue or overload that could send
fragments flying toward personnel or equipment.
Checking vibration - motors and
drives are a common source of
vibration and disruption
MarshMellow springs will generally be cost
competitive with standard coil springs. They will
often times be of lesser cost than custom-made
coil springs.
CONCLUSION
Both Airmounts and MarshMellow springs will
be superior alternatives to the cheapest passive
isolation option, rubber pads. Thin rubber
mounts are, just as they sound, a thin sheet of
rubber material. They are very limited in their
deflection capacity. Since deflection is inversely
proportional to natural frequency, the rubber
mounts’ inability to provide much deflection
means it will have a high natural frequency, which
will result in lower levels of isolation effectiveness.
REN168
36 August 2018