Cushioning a heavy impact

RICHWOOD has re-released a heavy-hitter in its product line-up, the heavy-impact Cushion Arc impact idler.
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Richwood's Cushion Arc working in the field.

Donna Schmidt

Published in the December 2009 Coal USA Magazine

Originally released to the mining industry in 2000, the company told Coal USA that the biggest change to the product this time around was a redesign of the unit’s top rubber rolls.

“These rolls are now completely molded as one piece containing a labyrinth, felt and lip seal in the deep groove sealed radial ball bearing shell,” resource planning and technical services senior manager Paul Patton said of the newest Cushion Arc released in June.

“This improves the performance and prolongs wear of the rubber roll.”

While the change has enhanced the product, the components of the product remain the same and it can still tackle the heavy-duty use the mines give it, even in extreme conditions. The roller segment includes five to nine individual rollers, each 6-inch diameter R2000 rubber molded over a 2.75 inch diameter steel shell.

Completing the assembly, each roller has permanently sealed ball bearings measuring 1.25 inches.

Cushion Arc’s roller frame has independent support for each impact roller within the main idler frame, making for an easy installation, and the roller T-frame can rapidly slide on and off for individual roller replacements.

“[The product] was developed as an adjunct to our Combi-Pact Impact Saddle, a heavy-duty impact cradle designed to be a direct replacement for impact idlers,” Patton noted.

“The great benefit of the Cushion Arc is the capacity to survive the heavy impact environment. Continuous UHMW (ultra high molecular weight) cradles more than 4-6 feet long tend to wear out in the middle of the span because of sag in the belt under load [but] the Cushion Arc in the array prevents the sag and improves wear in the array.”

He also pointed out that, as before, Cushion Arc is adaptable to the specific needs of mines. While carrying idler dimensions can vary largely among conveyor manufacturers, even at the same belt width and load rating, Richwood designs each application so the product is an exact match to the profile of other idlers on a mine’s conveyor structure.

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