Couplings are an integral part of every driveshaft assembly, but when it comes to mining applications, not all couplings are created equally, according to Shane Rock, Oceania Region General Manager for Regal Rexnord.

“As their namesake suggests, couplings are the connection point that brings the motor and the drive together to power a piece of rotating equipment,” he says. “And the way couplings perform under severe-duty conditions can make or break a drive system. Therefore, taking steps to optimise their selection is in the best interest of every mining operator.” 

Shane notes that there are many variables to consider when selecting a coupling arrangement for a piece of mining equipment. “Their torque rating, durability, flexibility, and compatibility with other drive system components are all features worthy of comparison during the design stage of any mechanical drive system,” says Shane. 

“Couplings are not something you want to compromise on because impeded performance of a coupling arrangement is detrimental to all the connected components,” he furthers. “The service life of the connected bearings, motors and drives are influenced by its resilience in application. And depending on the brand and the make, a coupling’s core differentiating features can have a serious impact on the performance and service life of a drive system.”

Since a successful merger with Regal last year, the Rexnord portfolio now stands as the largest manufacturer of couplings globally with the addition of the Regal’s Kop-Flex and JUARE brands to Rexnord’s diverse range of couplings products, including the Falk and Rexnord house brands.

Through joint efforts with Regal Rexnord, Motion Australia now has the ability to offer the most extensive range of coupling products available to the Australian market including gear, grid, jaw, elastomer and disc couplings. 

In addition to the breadth of their range, Motion Australia’s in-house engineering capabilities allow for the design and customisation of coupling arrangements for “just about every conceivable application our customers could require,” says Steve Hittmann, Category Manager for Mechanical Drive Systems at Motion Australia.  

“Because there are an infinite number of coupling arrangements and custom features, it’s best for mining operators to consult with the experts when troubleshooting problematic applications, he explains. “Our experienced engineers can address even the most problematic applications to find a coupling solution for any mine site. Customers should talk to one of our experts to learn more about how they can efficiently power their mining business.” 

In the following guide, Steve highlights some of the key coupling products from the Regal Rexnord range, designed to perform on mining applications.

GEAR – Falk Lifelign® Gear Couplings

Falk Gear Couplings are generally used for low-speed applications especially around gearbox outputs to conveyors or mills on any mine site. In particular, the Falk Lifelign® Couplings are designed to be an economical solution by extending maintenance intervals, reducing wear and increasing service life, according to Steve.

“Motion Australia and Regal Rexnord can supply alloy steels for hydraulic hub removal and increased wear resistance. We can also increase torque ratings by an average of 60 per cent for a slightly higher price point. This extra torque boost allows for smaller sized coupling to be used, thus significantly reducing overall costs.”

“It’s important to note that Regal Rexnord also supplies the largest gear couplings in the world for low-speed, high-torque applications or where bore capacities of 250mm to 1,320mm are required.”

GRID – Falk Steelflex® Couplings

The Falk Steelflex® Grid Couplings are generally used for high-vibration applications, especially around mills, grinders, crushers and pumps to connect either high-speed input or low-speed output shafts.

“Torsional flexibility allows the Steelflex® couplings to torsionally deflect shock or vibratory loads, providing flexible accommodation to changing load conditions. They dampen vibrations and reduce shock loads by as much as 30 per cent by relying on the predictable resilience of the steel grid for torsional flexibility. Consequently, the Steelflex® couplings tune the drive system by absorbing impact energy and spreading it over an increment of time.”

When coupling-connected equipment must be moved, the job takes longer and costs a lot more. But with the Steelflex® grid couplings, the grid provides a level of flexibility that helps to protect driving and driven equipment from excessive or undue bearing loads.

“The replace-in-place design of these allows flexible grid elements to be dropped in without the need to remove or reposition hubs or realign shafts.”

ELASTOMER – Falk Wrapflex® Couplings 

The Falk Elastomer Couplings are generally used for high-speed applications, especially between motor, gearbox, or pump inputs on mining applications. The quick and easy installation and replacement of the Falk Wrapflex® Elastomeric couplings has set a new standard for reduced downtime. 

“Because the connecting motors or drives don’t need to be moved during installation and replacement of these couplings, the need for time-consuming realignment is eliminated, further reducing downtime,” says Steve. 

Available in close-coupled and spacer designs, the Wrapflex® couplings accommodate up to 186mm shafts and torque loads up to 20,250 Nm. 

Falk LTG (Long-Term Grease) for Couplings

Both the Lifelign® (gear) and Steelflex® (grid) shaft couplings require lubrication. Regal Rexnord engineers have spent years measuring the wear rates on coupling components using various lubricants and coatings. The results of extensive research indicated that greases with high viscosities and low bleed rates produce the longest life. The Falk LTG is specially formulated to provide superior lubrication for flexible shaft couplings.