Air Springs Supply has released Marsh Mellow springs, a maintenance-free alternative to metal springs that do not require lubrication and will not suffer permanent compression.
These rubber-and-fabric springs, manufactured by Firestone, are suitable for applications such as shaker screens, crushing equipment, vibrating bins, conveyors and other equipment subject to vibration.
The springs operate silently with more spring travel and greater load capacities than conventional coil springs.
The cylindrical springs are constructed of a solid rubber core with a hollow centre and several plies of fabric-reinforced rubber as an outer cover. The plies provide the springs with stability as well as a consistent cylindrical shape.
The spring’s components (rubber, bias plies, size of centre) are combined in different ways to meet specific load and performance requirements (such as those of crushing and screening equipment), giving them greater flexibility and precision.
One of the major advantages of the springs is that they offer constant vibration isolation with changing loads. Their variable spring rate allows for a nearly constant natural frequency under the impact of such loads and because of their greater deflection capabilities – and the load-carrying influences of the fabric reinforcement – they can carry a greater load when compared to a solid rubber part of the same modulus and dimensions.
Their ability to maintain a cylindrical shape while supporting greater loads means a smaller overall size can be used compared with an all-rubber springs of identical load capacity. This is important when considering an application with a small design envelope.
Marsh Mellow springs’ high load capability also means fewer springs may be needed in an application, resulting in less overall cost. In addition, the lateral spring rate can be less than the vertical spring rate, resulting in a lower lateral natural frequency.
The springs’ low natural frequencies mean they provide isolation of forced frequencies in the range of 800-1200 cycles per minute (13-20 Hz).
Their flexibility also helps eliminate downtime and potential damage to machinery.