Comprising advanced pivot pin technology, Nord-lock bolting system’s Expander System, on offer from industrial solutions supplier BMG, offers dependable solutions that combat the challenges of lug wear in diverse applications, including earthmoving equipment.

Pivots, which are critical in any rotational movement, often experience lug wear, which occurs owing to the clearance between the bore and the conventional pin, explains BMG fasteners sales manager Maryna Werner, adding that this is commonly repaired with line boring – a technique associated with high costs and protracted downtime.

Through the advanced Expander System, consisting of a comprehensive range of robust components, BMG specialists are able to supply the correct pivot to prevent the problems that lug wear causes in order to increase uptime, enhance safety on site and reduce maintenance costs.

The severe vibration of heavy machinery, says Werner, is a major challenge in the mining industry for which BMG’s specialists recommend the use of the Expander System in conjunction with Nord-Lock wedge-locking washers, as an efficient vibration-resilient pivot solution for reduced maintenance and downtime in loading and hauling equipment, drills, excavators and mechanical scalers.

Safety and productivity are critical on any construction site, where the continuous operation of equipment and machines makes lug wear prevalent.

In these scenarios, the Expander System has been designed to extend the service life of pivot joints in articulated dump trucks, regular dump trucks, excavators, backhoe tractors, wheel loaders, cranes and bulldozers.

According to Werner, the Expander System is quick and easy to install and remove, allowing for on-site maintenance, substantially decreasing the production losses associated with downtime.

In addition to this, she highlights that in the oil and gas sector, the Expander System increases control and precision during the handling and setup of drilling equipment, while enhancing safety on the rig or extraction site.

This dependable system, she says, is also designed for efficient use in manufacturing and processing, such as in cutters, sludge filters, centre rollers and jack-screws in paper mills, and balers, intake and trimmers used in sawmills.

In energy plants, these pivot pins are used in roasters, stoker feeders and grapples; while in steel mills, they are used in cooling beds, tensioning arms, oscillator and segment machines, side roller guides and side tensioner frames, elaborates Werner.

Use Case

The Expander System – which comprises an assembly that includes an axle tapered at both ends, two expansion sleeves, two tension washers and two fasteners – has been designed for convenient onsite repairs.

Even in a situation where the lugs are badly worn, a repair can be made in the field, with less downtime.

The sleeves of the Expander System simply expand to conform with the wear pattern and lock the system in place, without the need for time-consuming and costly welding and line boring.

Once re-torqued, the system locks from both sides, significantly increasing stability.

The system has also been designed to improve safety on site, says Werner, adding that by replacing a traditional straight pin with an Expander System pivot pin of the same diameter, the risk of axle breakage is reduced and the strength of the machine is enhanced through the system’s double sided axial locking design.

Additional benefits include a permanent solution to lug wear and increased service life of bushings, bearings and seals.

A key advantage of this system over “conventional” pivot pins is pressure distribution. A conventional system only distributes the load onto a small area, whereas the Expander System distributes pressure over the whole contact area in the direction of the force.

Further, there is no requirement for additional fastening holes, threads or welding of locking rings on the machine, and no need for fine machining in the lugs, as the Expander System makes it possible to use in wide tolerances.

In addition to this, the Expander System can also be combined with Nord-Lock washers for enhanced efficiency in vibration-intense applications.

These customised Expander System pivot pins are specifically adapted to suit exact requirements, through the use of specific materials, hardening treatments, surface coatings and the correct tolerance for each application.