couplings

coupling
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Good vibrations with high performance steel grid coupling

In the mining sector, an effective grid coupling needs to stand up to earth-shattering vibrations, while at the same time, lending some flexibility to an application. “A heavy shock load can devastate a coupling arrangement even on the most robust equipment, which is why Rexnord developed the Falk Steelflex T-design range,” says Steve Hittmann, BSC’s National Product Manager for Mechanical Drive Systems & Belt Drives. “The aim with this product was to surpass competitors in performance and durability under high-impact conditions.” “In mining and quarrying, grid couplings will generally be used in the crushing, grinding, and agitating of material,” explains Steve. “They are also used in pump, conveyor, dragline, and high-speed gearbox applications, where they are really about the protection of the driven unit through their ability to absorb massive amounts of vibrations,” he adds. “Third party testing found that Falk Steelflex grid couplings are 4.7x more durable than a leading competitor’s grid coupling and 16x more durable than other brands,” furthers Steve. “Even though many grid couplings appear similar, a huge gap in performance remains between brands,” he emphasises. The technology was originally used in the production of aircraft components that carry heavy loads and deflect high vibrations in air. According to Steve, the key is torsional ability. “The Steelflex Grid Couplings employ torsion to deflect normal shock or vibratory loads, making them durable and flexible to changing load conditions,” says Steve. “In addition to this, Steelflex tunes the drive system. It absorbs the energy of impact by spreading it over increments of time, dampening the vibrations and reducing peak loads by as much as 30%,” he adds. The Falk Steelflex T10 Grid couplings are fabricated from steel for maximum strength; machined to within 0.001 inches, permitting utilisation of any hub surface for measurement of shaft alignment. “The tapered grids are made of high strength alloy steel, quenched, and tempered to spring hardness,” explains Steve. “The grid surface is then precision shot peened to compress the surface molecules for increased strength.” “The effect is a dramatic increase in rating, providing reserve strength for longer life or allowing a smaller size coupling to be selected,” he enthuses. Read More
coupling
 Features

Let’s torque about tyre couplings

Where there is movement, there is power. A coupling takes that power and transmits it from one shaft to another, which may sound simple enough in theory. A kid pedalling a bike turns the bike shafts, which takes the power to the chain. In a bike it’s a chain. In a car it’s a drive shaft. But what about on a slurry pump at a mine site? This is where CBC’s expert on Power Transmission, Troy Markland, comes in. “Slurry pumps have two shafts, one for driving and the other being driven. The power comes from the motor and transfers to the turning shaft through a coupling arrangement,” explains Troy. “Joining two aligning shafts is very difficult to do without any deflection and misalignment.” For this application, Troy recommends the Fenner FenaFlexTM Tyre Coupling for high flexibility, which he explains is critical on mining applications. “Fenner® power transmission products have a long history in the mining sector,” says Troy. “From a coupling perspective, Fenner® is widely used by major pump companies, particular on high-speed applications.” According to Troy, this is due to their premium manufacturing facilities, installation services and highly involved after-market support. “Fenner® couplings are a robust choice for major pump applications for above ground and below ground operations because they have very good horsepower and misalignment capability,” he explains. “The coupling has up to a 4-degree misalignment which is very good for accommodating the gap between shafts.” To check that the flanges are parallel with the shafts, CBC technicians take various measurements to ensure the gap between the shafts allows for end-float. “Since the Fenner® couplings can accommodate a high degree of misalignment, this makes it easier to test for torquing ability, says Troy. “Sometimes we use a laser alignment tool or an alignment shim to check that the installation is parallel to the unit on all sides.” The couplings have a donut-style hub between two flanges that create flexibility for shaft-to-shaft misalignment. Read More