The Swiss construction company, Aregger AG, chose Liebherr Machines Bulle S.A (Switzerland) as its partner for customising the hydraulics for the Europe's biggest demolition excavator. Two Liebherr mining excavators served as the basis for this about 300 tonnes excavator. For more stability, the uppercarriage of an R9150 was combined with the larger undercarriage of an R9200. For even higher stability and more secure stability during demolition work, Aregger also had the undercarriage equipped with a hydraulically extendable track.
The additional hydraulic functions, such as the telescoping of the boom, require adaptation of the original hydraulics. For this, the existing drivetrain needed to be separated. An extra pump had to be configured between the DPVG280 slewing mechanism pump from Liebherr and the fitted triple gear pump for auxiliary functions, to enable the additional demolition functions, such as the turning of the demolition shears and the telescoping of the boom. For this, Liebherr designed a DPVO165 hydraulic pump, which could easily be integrated into the existing drivetrain. For attachment to the DPVG, Liebherr chose a corresponding adapter along with a driveshaft for connection to the triple gear pump from its modular system. The pump could, thus, be seamlessly integrated in the machinery. "Right from initial operation, it was evident that the decision of Messrs. Muri on the use of additional components from Liebherr had proved to be of great benefit", says Franz Muri, engineer.
These four operation pumps as well as the slewing pump from Liebherr considerably increased the hydraulic performance of the demolition excavator. The core component of the machine - the 12-cylinder D9512 diesel engine with a power output of 565 kW and a displacement of around 25 litres - is also from Liebherr. Furthermore, the hydraulically-extensible running gear allows the width of the new excavator to be shortened, providing advantages in transportation.
More than three years were spent working on the design of the A-Rex M9300. During this time, Franz and Christian Muri, engineers from the Aregger family company, studied carefully the particular requirements of the dismantling segment. The functional extensions of the drivetrain were implemented in close cooperation with Liebherr Machines Bulle S.A. In this way was produced what is now Europe's largest demolition machine which, with its working height of 70 m including boom, is capable of handling operating weights of up to 300 tonnes. Currently, this giant is at work on the dismantling of the Schweizerhalle in Basel (Switzerland), where it has been successfully deployed since mid-June.