Low-maintenance linear adjustment of driver's seats in construction site vehicles

As no road traffic regulations apply on construction sites, it is all the more important for drivers of construction machinery to have good all-round visibility. This is not always easy. Especially with particularly wide excavators or wheel loaders, the field of vision is very limited. In order to have a complete overview of the surroundings, the vehicle must be stopped and the driver must leave his seat. Gessmann's operating concept is based on offering the driver the greatest possible flexibility by moving his control position.

The objectives of W. Gessmann GmbH during development were clear: the driver's seat should be able to be rotated on its own axis and also moved at right angles to the direction of travel. The operator should be able to change position within seconds in order to regain an overview of the entire machine environment as quickly as possible. In addition to the high level of flexibility, the operating concept must also be able to withstand the harsh construction site conditions and be extremely low-maintenance. 

Originally, the design was to be guided by recirculating ball bushes and a stainless steel guide shaft. However, due to the hardened steel balls rolling over the ground stainless steel guide, this system was not ideal for the planned application. This is because construction machinery vibrates strongly, which can cause the steel balls to damage the stainless steel shaft, thereby increasing the displacement force and greatly reducing the service life.

Instead of recirculating ball bushes, Gessmann uses drylin® W guide rails for seat adjustment, on which drylin® hybrid double roller bearings run. These have proven to be a durable solution, particularly with regard to use on the construction site. The tribologically optimized high-performance plastics are lightweight and corrosion-free and, above all, do not require external lubrication. This increases service life in moving applications, as no adhering dirt affects the bearing point. The Gessmann developers also came to this conclusion after initial tests with the bearings. However, advantages were also achieved in the design. For example, the small installation space of the drylin® W-series allows the guide system to be fitted underneath the machine floor. This means that the system is better protected from the weather and heavy soiling. Overall, the drylin® bearing is also more favorable compared to recirculating ball bearing bushes with a stainless steel guide shaft. Both in terms of purchase price and ongoing maintenance costs.