The demand for low-maintenance, cost-effective couplings has increased year-on-year, with the emphasis on ease of assembly to alleviate hours of downtime, says industrial products provider BMG power transmission product manager Brandon Bouillon.

BMG supplies premium Timken Quick-Flex couplings to the Southern African mining sector.

“Despite the tough trading conditions on the back of Covid-19, the Quick-Flex couplings constitute about 30% of BMG’s engineering couplings sales. “We have been experiencing double-figure market-share increases yearly,” he tells Mining Weekly.

The Quick-Flex couplings, which require minimal to no maintenance, can withstand extreme applications, such as in pumping environments, in the mining sector. Pump applications are critical in the mining process and are typically exposed to harsh environmental demands.

“These couplings have the ability to accommodate multiple environmental and application demands such as torque fluctuations in hydraulic pumps systems. “These low-maintenance couplings dampen vibration and torsional shock loads experienced in operation,” Bouillon says, adding that they are designed to transmit torque from a driving shaft to a driven shaft, and to accommodate shaft misalignment within the drive.

The Quick-Flex couplings are also useful in hydraulics, gearboxes, compressors, vibrator screens and fans.

“An advantage of the Quick-Flex drive couplings over conventional units is that they allow for the direct replacement of virtually all comparable sized couplings. “Moreover, they require no lubrication and are also easy to install and maintain because they are fitted with a rubber element that does not require any continuous maintenance,” Bouillon says.

Owing to the high torque capacity of this range, the Quick-Flex solution chosen is often smaller than the replaced coupling, he adds. This leads to a significant weight saving on the drive and also reduces stress on other components.

He notes that these couplings are ideal for heavy startups of shock loads because they have an impact load capacity of more than 200% of the maximum torque rating.

Technical Details

The Timken Quick-Flex is compatible with shaft sizes from 10 mm to 286 mm and can accommodate a wide speed range – from below 100 rpm to 12 000 rpm. Torque ratings range from 43 Nm to 188 795 Nm, depending on the selected element and cover design, Bouillon explains.

The couplings consist of two steel coupling hubs, which are attached to the drive and driven shaft. A urethane element wraps around the two hubs and provides an effective drive mechanism. The only spare part required is a standby element that can be quickly changed when necessary. The cover, which secures the insert in place, can be installed on either side of a standard coupling hub and will not move under misalignment.

Once the two coupling hubs, insert and cover have been installed and aligned for the first time, the coupling hubs do not need to be moved again for the life of the equipment. Unlike a standard jaw-type or gear coupling, there is no metal-to-metal contact between the hubs.

This prevents any possible damage to the ironware during an element failure. The urethane insert can be easily changed without moving the hubs or shafts and no re-alignment of components is necessary.

Inserts, which are resistant to chemicals, are manufactured from different grades of urethane to suit various industries. The red insert is made from relatively soft urethane and is suitable for most high-speed applications with high levels of vibration. This insert is also designed for quick starting and stopping of high inertial loads and for reversing applications.

The Quick-Flex couplings, with the stiffer blue insert for higher torque applications, can withstand temperatures of between –50 ºC and 100 ºC and are an efficient replacement for gear, disk or grid-style couplings.

White inserts are manufactured from a heat-resistant urethane compound for high- torque and -temperature applications of up to 177 ºC.

Couplings with the black insert can withstand extremely high torque requirements, replacing gear-style couplings.

The flexibility of this design makes these couplings suitable for many applications – from high speed/low torque excessive vibration drives to low speed/high torque applications. These couplings accept angular misalignment of up to 2º, parallel shaft displacement of up to 2 mm and a maximum axial misalignment tolerance of 7.92 mm.

Most heavy-duty couplings require interval lubrication by means of greasing to ensure the life expectancy and performance of the coupling are achieved. The Timken Quick-Flex coupling does not require this – the cover is simply removed and a visual inspection is made.

“If there is any wear on the element, it can be quickly and easily replaced without having to move any of the machinery. “After the initial installation of the coupling, only the consumable wearing part – the coupling element – is required from a maintenance perspective,” Bouillon says.

He explains that BMG’s team of mobile technicians with specialist technical skills and equipment can conduct breakdown and routine maintenance on site. This team carries out troubleshooting and advises on possible productivity improvements.

Specialist services include the installation, adjustment, replacement and maintenance of components, shaft and pulley alignment, balancing, condition monitoring, oil sampling and analysis, as well as critical equipment inspections and lubrication schedules. Maintenance training and fault diagnosis also form an important part of BMG’s field services.

Through BMG’s assistance with careful and accurate product selection, the correct installation and appropriate care of couplings, substantial savings can be made through reduced maintenance costs and minimal downtime, Bouillon concludes.