The Pulley – A simple part that can stop an entire plant
A conveyor pulley does something almost trivially simple: it moves or turns the belt. But as plants and mines have changed, pulleys have become more important. Where a site once ran two conveyors side by side, many now run a single larger one: more capacity, fewer spare parts, less to maintain. It also means a single point of failure. In the worst case scenario, when one pulley goes, the whole mine or processing plant stops with it.
That’s why it takes a serious amount of expertise to choose (or design from scratch), install and maintain the right pulley.
A product range that reflects a history of solved problems
ROXON’s conveyor pulley’s have evolved over decades as customers had problems that the previous design couldn’t solve.
The welded-shaft pulley is the simplest and cheapest, with the shaft welded straight to the pulley body. If the shaft fails, the whole pulley fails with it. Welded-shaft pullies also struggle under high belt tension. Not a recommended choice for any critical conveyors.
The live-shaft pulley clamps the shaft with a locking element instead of welding it. Now the shaft can be replaced and the pulley refurbished rather than scrapped.
In a dead-shaft pulley the shaft does not turn and the pulley rides on bearings mounted between the shaft and the pulley body. That design carries roughly twice the load of a welded-shaft pulley.
For special conveyors or conditions, ROXON can also produced engineered-to-order pulleys. They are usually designed for one specific conveyor and calculated to the last detail.
While these are the basic differences between pulleys, other factors such as alternative, non-centering locking devices, different bearing centers, shaft materials etc impact the price of the pulley.
Besides the type of the pulley, the lagging material of the drive pulley is the third most important choice to make. Different lagging materials such as steel, rubber and ceramic have different use cases but their choice can also impact pulley size. Adding a lagging material that produces a higher friction can help reduce the sizes of the drive pulley and the counterweight.
Knowing which of these a given conveyor actually needs is the real skill and that’s where pulley expertise is benefificial: it can save you money upfront but also in minimizing pulley-related downtimes.
What experience actually buys you
Reliable and safe — just like your classic Swedish car. Even a standard pulley should be built to that standard: but it works, every time.
To get to that standard – and go far beyond it as well – takes years of experience. At ROXON’s pulley manufacturing facility in Haparanda, Sweden, most careers are measured in decades. Experience shows up in the details that never appear on a spec sheet. The limits of how far a tube can be machined. When a large or high-tension pulley needs stress relieving. These are exactly the things a customer’s own drawing tends to miss, for example a dead-shaft pulley specified with no bearing clearance: correct on the drawing, doomed in service.
Designing for the system, not the line item
A pulley can’t be chosen in isolation. Lagging changes belt tension, tension changes pulley load, and load changes the bearings and shaft. Optimise the conveyor and you optimise the pulley. Sometimes the smartest move isn’t a bigger pulley at all but an extra one as increasing the belt wrap lets every pulley and bearing get smaller.
Standardisation is part of the same thinking. Because standard pulleys are built from stock sizes, spare parts are still available years later.
That approach is what makes the our deliveries quick when it matters. When a conveyor fire hit a plant, ROXON delivered around 27 pulleys in two weeks. When a pulley failed at a customer site on a Saturday morning, we had a replacement running by Sunday. With roughly 100,000 pulleys built since the factory opened in 1975, that responsiveness comes from experience and a deep stock.
A pulley is a simple part. Choosing the right one, and building it to last, is not.
Want to talk through the right pulley for your conveyor?
Get in touch with our team or view the entire ROXON catalogue of pulleys.
