A new high speed impact cradle is designed to reduce roller and frame damage from heavy conveyor loading conditions in mining, coal handling, aggregates and other applications involving dense materials and/or high volumes. The rugged EVO® High Speed Roller Cradle is engineered to withstand brutal operating conditions, reducing roller failures and service requirements. One customer estimates that the new cradles from Martin Engineering paid for themselves in just the first week of service at the company’s copper handling facility, due to the savings in maintenance and downtime.
"Under high-volume conditions, standard OEM impact idlers in the load zone simply can’t withstand heavy loads and lengthy drops, costing downtime for repairs as well as the expense of replacement components," observed Martin Engineering Service Technician Doug Brown.
The new cradles use Martin Engineering’s Trac-mount™ technology to slide in and out easily for maintenance. The modular components are light enough to be removed by hand, without using a crane or other equipment to handle them.
"The new cradle design only requires one person to change the rollers when the time comes," said Brown. "The biggest problem solved is the downtime. In the past, when customers have needed to change rollers or frames, they had to shut down the conveyor for an extended amount of time," he explained. "Old style frames can be difficult to remove, requiring that maintenance personnel pull the arms down, then jack up the assembly to pull it out."
"We wanted something that was slide-in/slide-out," added Martin Engineering Global Product Manager Chris Schmelzer. "These new cradles were designed using Finite Element Analysis, so we could confirm that they’d be strong enough, without having to overbuild them," he explained. "We can make it as strong as it needs to be, without adding excess weight, so workers can remove and replace components without using heavy lifting equipment."
The innovative load zone design uses an elastomer bar suspension system that absorbs and distributes the material load being transferred, greatly reducing the stress on the idlers’ rolling components and support structure. One patent-pending design innovation is the use of connecting brackets near the top of the idler frame to hold the three rollers together. These special brackets are designed to allow multiple modular cradles to be tied together, so that the idlers throughout the entire load zone work together as a system.
"This cradle is simple to install, and the easy access to the center roller makes the maintenance a one-person job," Brown added. "In addition to greater durability, it’s intentionally designed to facilitate service, making the task of changing rollers safer and easier."