Excavating and grabbing with an additional degree of freedom

L&K Land- und Kraftfahrzeugtechnik GmbH is known in the construction machinery industry as a manufacturer of particularly durable equipment for excavators, wheel loaders, telescopic handlers and special vehicles. The buckets, backhoes and other tools are customised in numerous variants. Extremely wear-resistant Hardox steels and iglidur® bearings ensure a long service life under adverse conditions and dynamic loads.
 
For excavator operators and construction machine rental companies, they are "just" a tool - but one that has to fulfil the highest requirements in terms of load capacity and wear resistance. This is because the shovels and clearing buckets of excavators and wheel loaders, which we are talking about here, dig into the material with high dynamics during each individual operation and encounter resistance such as hard rock.
 
The environmental conditions for this work are unfavourable, not to say extreme: the construction machinery can be standing in water or removing highly abrasive material. The stresses acting on the tools are very dynamic and almost impossible to calculate, especially as the equipment is also subjected to one-sided loads and is often "misused" on the construction site.

The bearing point must be maintenance-free for a total of over 4,000 hours of use. Regardless of whether the excavator is standing in water or removing highly abrasive material. The bearing points are also exposed to heavy loads and impacts. The stress caused by dust and dirt is an additional challenge for the bearing points.

With maintenance- and lubrication-free iglidur® bearings, the required service life was even exceeded. Despite the highest loads, there were no complaints or need to lubricate or replace the bearings even after 5 years of use. They are also around 40 per cent cheaper than the previously installed composite bearings.

Many manufacturers, rental companies and users of construction machinery do not want "08/15" tools for such conditions, but tools that are characterised by a long service life and often also by special manoeuvrability and additional degrees of freedom. They are in good hands with L&K Land- und Kraftfahrzeugtechnik GmbH in Stadtilm, Thuringia. For more than forty years, the company has specialised in developing high-quality tools for construction machinery.

The broad standard programme, which includes all types of backhoe buckets, high-tipping buckets and side-tipping buckets, is the basis for a wide range of special designs. This is because the tools are always manufactured to customer specifications, and with a short lead time. Dipl.-Ing. Wolfgang Anderle, Managing Partner of L&K: "We deliver at short notice, usually within two to three weeks." The modular design of the programme contributes to this, as does the modern production with CNC machines in all areas. Another important factor for the high quality and short delivery time is the expertise of the welding specialists that L&K trains and develops in its own DVS training centre.

The first tests were carried out to the complete satisfaction of both the L&K engineers and the users. The ultralight design, which is supplemented by iglidur® plain bearings, is now protected by a utility model. It is used in a wide variety of shovels, buckets and special tools - for example in high-tip buckets, which are used as salt loading buckets in the salt depots of municipal utilities, and in various types of grab buckets and trench buckets. L&K has also realised a real "XXL application" for the maintenance-free iglidur® plain bushes in a high-tip bucket with a capacity of 8.5 m3 several times.

The designers of L&K use bushings with diameters of 40 to 80 millimetres made of the universal material iglidur® J and iglidur® P, which remains particularly dimensionally stable under high loads and changing ambient conditions, including humidity.
 
Another positive aspect from the L&K designers' point of view is that the iglidur® bushings can be exchanged 1:1 for the bearings made of metallic composite material: A change to the surrounding design is not necessary. And both purchasing and production are satisfied with the fast delivery by igus® in small batch sizes: This is because L&K usually only requires two bushings per mould.