It's funny how many of the best ideas come about almost purely by accident. Take for example the TuffCore conveyor pulleys manufactured by Bryant Products. The story goes that Bryant president Fred Thimmel was sealing around a window with some expanding foam filler, when some of the filler was spilled on one of his tools and set hard. The light weight of the filler belied its strength: Thimmel tried to peel it of, break it off, cut it off - all to no avail. In the end, he had to resort to a large hammer to try and smash it off.

That combination of light weight and extreme durability sparked an idea for Thimmel, whose company specialises in conveyor components. A major problem with traditional steel conveyor pulleys is their weight. Not only does this add inertia to the conveyor system which introduces a host of performance compromises, it also has implications for shipping costs, installation effort, wear on the rest of the system and of course energy costs. But conventional thinking says that conveyor pulleys have to be made from steel to offer the required durability.

But why not, Thimmel wondered, manufacture conveyor pulleys using some form of foam inner instead of steel? After much experimentation and testing with different materials, the result is the TuffCore pulley, a patented design that comprises a TuffCore, closed cell, rigid urethane foam roller around a still shaft, that is lagged as standard with Bryant's proven TuffCote Durathane. The TuffCore pulley offers a huge weight advantage over steel alternatives, delivering a host of performance benefits and significantly lower cost.

Because they weigh almost 50% less than their steel counterparts, they require less drive power, which in turn means smaller motors, gearboxes and bearings can be used, so reducing energy demand. Indeed, the whole conveyor system can be more efficiently designed, with a reduced need for supporting structures. Lower pulley weight also means there is less wear on other system components, so you'll see longer bearing life and reduced gearbox wear.

Further, there is reduced inertia which offers the potential for significantly increased performance in the conveyor system. With less inertia to overcome, conveyors can start, stop and reverse quicker and index more accurately. Just think what this could mean in application such as shrink wrapping, or on indexing systems, sortation and accumulation machines.

Improved balance and run-out are further advantages of Bryant TuffCore, particularly important factors on high speed conveyor applications. The total indicated runout (TIR) of the Bryant product is typically 90% better than its conventional steel counterpart. The foam and lagging combination eliminate the need for balancing, again reducing cost. Users will also notice a sharp reduction in structure born noise and vibration.

The Bryant pulley is moulded not fabricated, greatly simplifying production and associated costs. It has no steel shell, steel end disks, hubs or bushings eliminating the need for secondary machining, finishing and time consuming assembly. It is also maintenance-free. Removing all of that steel from the pulley also brings greater pricing stability. While steel is prone to wild swings in price, chemistry is far more stable.

Suitable for OEM design or retrofitting, the TuffCore pulley is a fully tested, proven innovation. Bryant has conducted over four years of destructive testing internally, while clients have performed a further twelve months of accelerated testing. Further, The TuffCote lagging has over twelve years success in the field, proving vastly superior to conventional rubber lagging. It is non-hydroscopic, does not weather check, and there is no particle or dye transfer with moulded belts.

As both the foam and lagging are chemically inert this product can effectively replace stainless steel.  Substantial cost as well as weight savings result.  Bryant TuffCore pulleys for any application requiring corrosion resistance are manufactured from the same TuffCore and TuffCote materials as the standard type but have a stainless steel shaft. The product is highly chemical- and water-resistant and therefore eminently suited to wash-down processes.  

All crown types are available in the Bryant TuffCore product programme and pulley diameters are not limited by available tube sizes. This results in shorter lead times as it is adjustment of foam thickness rather than the incorporation of heavier walled tubing that adds diameter. The Bryant manufacturing process also provides the lowest cost method of producing V-guide pulleys as no machining or secondary operations are required.

The TuffCore pulleys are being introduced into the UK market by sole UK distributor RA Rodriguez. The pulleys are available in diameters from 75-300mm, and with face widths up to 1200mm, for belt loads from 225-450kg and conveyor speeds of up to 300m/min.