Maintenance-free plain bearings for reliable tipping device on forklift trucks

Profile

• What was needed: iglidur ® G plain bearing
• Requirements: Dusty, dirty and humid ambient conditions require resistant and corrosion-free plain bearings, no lubrication desired, durability and reliability
• Industry: Mechanical engineering, sorting, packing and palletising solutions
• Success for the customer: igus® plain bearings fulfil the requirements for simplicity and reliability, the material performs maintenance-free under difficult environmental conditions and under high weight loads

Problem
The Sorter company in Poland focuses on the design and sale of a range of technologically advanced machine solutions, from sorting machines to packing and palletising solutions.
One such solution is a special piece of equipment - a so-called tipping chair or 'tippler', which is mounted on a specially designed forklift. As the name suggests, this application performs a 180° tilting movement, which is used to empty the contents of pallet boxes. Such systems are primarily used in the further processing of fruit, for example to safely feed low-quality apples into a collection container. The device picks up the fruit in the collection containers and, thanks to the lateral tilting movement, ensures that the fruit can be tipped out without high impact force.
When designing the tipping device, however, the problem was that there were high demands on the bearing of this system. It was important to guarantee high process accuracy and minimise friction. Until now, only regular lubrication of the system could guarantee the maintenance of machine operation, but this was not desirable.
In addition, all individual parts must also be able to withstand high loads. This means that pallet boxes weighing up to 600 kg may well have to be turned.
In addition, the system usually works in a dusty, dirty and - due to the processing of fruit - sometimes humid environment. Other systems tend to corrode after a short time. In addition, the diameter of the main drive shaft must be as large as possible in order to be able to move the load on it at all.

Solution

As part of the project planning, Sorter's designers had considered various systems. However, metallic bearings confronted the planners with various problems ranging from susceptibility to corrosion to the need for regular lubrication of the system. After searching for other solutions that were more compatible with the environmental conditions and the high demands on durability, they finally found what they were looking for in the bearings, sleeves and guidance from igus®. Specifically, iglidur ® G bearings of the GSM-110115-110 type are used as bearings today. iglidur® G is the decathlete among the iglidur® materials. It performs extraordinarily well in all technical disciplines and is the classic all-rounder, especially with regard to the general, mechanical, thermal and tribological specifications.
The iglidur® bearings bring several advantages to the machine concept. Firstly, they solved the problem of lubrication. The iglidur® G material saves the user further time and costs, as it works completely lubrication- and maintenance-free. The bearings are also insensitive to dust and dirt, making them perfect for use in the working environment envisaged by Sorter. The solution also fulfils all other requirements that were set as part of the project planning and primarily related to the simplicity and reliability of the design.
In particular, the very good friction coefficient of the plain bearings plays into the idea of component longevity. The bearings work reliably and enable the system to operate properly, even under high weight loads.