Rubber spring advance expands advantages over metal in process and manufacturing applications
Rubber springs have long been attractive for industrial applications because of their reliability, light weight and basic simplicity.
But to obtain the load requirements for many applications, solid rubber springs were either too large physically, or became unstable laterally when made long enough to provide good isolation characteristics.
The concept of stacking rubbers springs answered the latter problem, but introduced the need for complicated mechanical guidance systems to control the lateral stability problem.
A rubber spring design that solves this basic problem is the MarshMellow® spring from Firestone Industrial Products, represented in Australia by Air Springs Supply Pty Ltd.
Marshmellows(R) provide a new and unique way to make use of the many advantages of rubber as a suspension and isolation element in major applications, including vibrating screens, conveyors and particularly corrosive processing and manufacturing environments that may damage metal springs.
The basic construction of the Marshmellow® springs includes a solid rubber core with a hollow centre, reinforced covers and specially designed tapered ends.
"The controllable variables of this construction are the secrets to the extreme design flexibility the spring offers, says actuation and isolation specialist James Maslin, who is National Sales and Marketing Manager for Air Springs Supply. "Changes in taper, rubber durometer (or hardness), or changes in cord angle or bias result in dramatic changes in operating characteristics of the products."
The characteristics of the MarshMellow® design facilitate a constant natural frequency and variable spring rate to provide constant isolation over a wide range of loads. Compared with traditional rubber springs and steel coil springs, Marsh Mellow offer:
- High degrees of vibration isolation, as well as lateral vibration isolation and consistent vibration isolation with changing loads
- Low natural spring frequencies to provide excellent isolation of forced frequencies in the range of 13-20-HZ (800-1200 cycles a minute)
- Compact overall size with high load capacity and increased stability at higher percentages of compression
- Greater allowable deflection and greater length-to-diameter ratios for machine design flexibility and simplicity
- Long life durability and corrosion resistance to eliminate downtime and potential damage to machinery
- Low cost and maintenance-free performance with effective noise reduction.
Marshmellow® springs can be an effective isolator in virtually any application where an air supply is not available for traditional air springs, such as the Firestone Airmounts® and Airstrokes®, for which Air Springs Supply is also Australian distributor.
Their outstanding performance - and a maximum load range now extending from 1.4 kN up to 88 kN (on special order) - makes them particularly suitable for vibration isolation applications beneath such equipment as bin hoppers, compressors, crushers, blowers, motors, HVAC installations and vibrating screens, says Mr Maslin.
Air Springs engineering team experience spans several hundred applications of both solid and hollow (bellows-type) air springs throughout Australia over more than 20 years. Details of applications can be researched on Air Springs' website, www.airsprings.com.au.) Naturally different types of springs have different performance characteristics suited to particular tasks. These should always be discussed with suppliers having wide experience in the particular area of application being considered.