BMG’s Nord-Lock range of bolting solutions includes Expander System pivot pin components that comprise advanced pivot pin technology, to offer dependable solutions that combat the challenges of lug wear in diverse industries.
Pivots, which are at the centre of any rotational movement, often experience lug wear, which occurs due to the clearance between the bore and the conventional pin. This is commonly repaired with line boring – a technique associated with high costs and protracted downtime.
“Through Nord-Lock’s advanced Expander System, which consists of a comprehensive range of components, BMG specialists are able to supply the correct pivot to prevent the problems that lug wear causes excavators, mobile cranes and dump trucks, in order to maximise uptime, enhance safety on site and minimise maintenance costs,” says Wean Marais, national product manager, Nord-Lock Group, Fasteners Division, BMG.
“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 minimum 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 retorqued, the system locks from both sides, significantly increasing stability.
“This system has also been designed to improve safety on site. 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.
“There are many other benefits, which include a permanent solution to lug wear, quick and easy installation and removal, increased service life of bushings, bearings and seals and greater safety. A key advantage of this system over conventional pivot pins is pressure distribution. A conventional system only distributes the load onto a very small area, where the Expander System distributes pressure over the whole contact area in the direction of the force.
“There is no need for additional fastening holes, threads or welding of locking rings on the machine and no need for fine machining in the lugs, as this system makes it possible to use wide tolerances. The Expander System can also be combined with Nord-Lock washers for enhanced efficiency in vibration-intense applications.”
BMG’s 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.
This system is suitable for use in many industries, including construction, steel, railway, bridge building, mining and quarrying, forestry and agriculture, manufacturing and processing, shipbuilding, marine energy and power generation, oil and gas, transportation and machine building.
Severe vibration of heavy machinery is a major challenge in the mining industry. BMG 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, drilling, 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. The Expander System has been designed to extend the service life of pivot joints in articulated haulers, excavators, dump trucks, backhoes, wheel loaders, cranes and bulldozers.
Nord-Lock Expander pivot pins, used by many leading OEMs, have been endurance tested for over 50 000 hours without failure and more than 1-million pivot pins have been installed in over 60 000 applications.