A Pin Upgrade for Kafril Group’s Hitachi Demolition Excavator (‘Beast of the East’)
For the German construction company Kafril Group, durable components and reliable suppliers are key to maintaining their modified Hitachi ZX 870-3 XXL, a high reach excavator with an extendable 50-meter boom arm. Known informally as ‘Beast of the East’, both for its location (near the German city of Leipzig) and its role in heavy-duty industrial demolition, Kafril’s Technical Manager Markus Kubaile turned to Expander System to upgrade the pivot pins on one of the country’s largest construction excavators.
“It’s important that our machines are maintained efficiently, even in the event of major failures. Part of that is having reliable spare parts suppliers and the ability for our field service team to conduct repairs on site,” says Markus.
‘Beast of the East’ is assigned to projects across Germany, and sometimes further afield, so it can be challenging to find local service providers who can work with such a special machine. Yet uptime is a matter of remaining competitive for the group, which is especially important during unpredictable market conditions. Kafril not only need to meet the safety and reliability expectations of clients in some of the toughest demolition jobs, but they’re also working towards ever-tightening deadlines and need to guarantee that projects will run on time - so a good result depends on as few breakdowns as possible.
A design upgrade built to last
With workshop time recently scheduled for significant maintenance, Markus says that Kafril overhauled the Hitachi excavator in order for it operate continuously over the next few years, without the need for further major repairs. “We take the planned downtime now so that the machine can work for longer away from the workshops, and we try to minimize future wear down to zero,” he explains. Part of those refurbishments included switching the existing axles for Expander System pivot pins.
The performance of pivot points directly affects a machine’s ability to perform its task safely and with high precision, but traditional pivots are subject to wear over time due to the clearance between the bores and traditional straight pins.
With ‘Beast of the East’, the extreme height and weight of the equipment accentuates the wear caused by swinging and movements in the extended boom arm, with much higher forces than experienced in smaller excavators.
Expander System pivot pins reduce wear in intensive industries
By design, Expander System pivot pins eliminate those small tolerances needed to install a traditional straight pin into bore holes that have a marginally larger diameter. As a modular system (consisting of a tapered axle, expanding sleeves and various fastening assemblies) Expander System locks into place from both sides when tightened, improving the stability of moving mechanical parts and reducing wear/service intervals.
Markus had previous experiences with Expander System, discovering it when repairing a large Volvo machine. He says that “at the time, I wasn’t aware where this solution came from, but it was clear that the assembly was showing far less wear than you would expect from a standard pin.”
Customizing Expander System for the Kafril Group
Three Expander System pins were designed for Kafril’s machine, with the largest being 120mm in diameter and 885mm long.
Nord-Lock Group Sales Engineer, Michael Held, explains that “the design of the biggest Expander System was quite unusual. The pins had to double-up as ‘hook extensions’ to facilitate better storage and transportation of the boom arm, as the excavator switches between two special units.”
A regular hooked nut would require a tightening torque of 600 Nm, so a compact Superbolt multi-jackbolt tensioner was also added, something which Mathias Olofsson, Expander System Product Manager, remarks is “a perfect fit for this design.”
With Superbolt, each jackbolt can be tightened with just 30 Nm of torque, “so we can do installation and removal of the entire pivot joint in restricted spaces and without special tools,” says Markus.
Field installation with simple hand tools
Because Expander System can also handle existing wear in the pivot joints (to a degree), Kafril could install their new pins directly – without the need for line boring and welding to restore the machine to its original tolerances.
“We’re talking about avoiding a considerable additional effort, because we’d need to plan that workshop time, transport the machine and completely disassemble the arm if we had to restore the pivot joints first,” says Markus.
Instead, Expander System was installed on-site in the morning and Kafril’s Hitachi ZX 870-3 XX was quickly back operational. We left the team to prepare for the demolition of a 45-meter silo in the German state of Thuringia, but not before a final word from Markus:
“If you want to keep the wear as low as possible, I can recommend replacing the axles with Expander System – even better would be to have them as an original part to be built by the manufacturer.”
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