Moisture, salt, dirt, sand, oil, and rough construction debris; there is no limit to what high performance sweepers may run into on large and small surfaces. These sweeper systems must be rugged and economical, as well as having a reliable, long service life. The use of plastic plain bearings at particular trouble spots in these types of sweepers ensures long-term reliability. In fact, the operational results of these bearings in the sweepers’ everyday operation has been so overwhelmingly positive, they are now the go-to solutions for new areas of application.
“Our sweepers do not surrender before any demand,” Helmut Schmeh, Managing Director of FAUN Viatec GmbH, explains on site in Grimma, Germany. “They cover every work are and ensure an impressive sweeping performance, even when under the most difficult conditions.”
Whether for a street sweeper for daily use in municipalities, or for those used in extreme conditions like those found on construction sites, as an airfield sweeper for airline runways, or small, maneuverable sweepers for small areas, these types of sweeper systems prove their ruggedness around the world in an array of types and sizes. They show their efficiency even in steel factories, coal mines, or in the removal of oil residue. Niche areas, such as rail cleaning and weed removal are also covered with corresponding system accessory parts.
“We attach the utmost importance to the development of practical solutions that have proven themselves day in and day out under harsh everyday use,” says Helmut Schmeh. “We are committed to the manufacturing base in Germany. Out sweepers are customized developments; unique pieces that are designed in close cooperation with the respective site requirements.”
The rugged mounted sweepers are used for the daily work in cities and towns or for the most severe use on construction sites, in steel factories, in coal mines, as an airfield sweeper to clean the runway tracks, or as a maneuverable sweeper for small areas.
The product range consists of a wide variety of truck-mounted sweepers. The chassis weigh between 8.3 and 22 tons, with a structural volume between 141 and 318 ft3. “In many technical developments, we are trendsetters,” says Helmut Schmeh. “Our patented air recirculation system, for example, provides maximum physical performance and operational reliability in conjunction with different standard chassis. We focus on current environmental issues, such as drive technologies, fine dust reduction, fuel consumption, and noise optimization. At the same time, the vehicles are designed for low operation costs throughout their entire service life.”
To ensure the long term durability of the sweepers, the company decided to use self-lubricating, maintenance free plastic plain bearings from igus®. Bearings made from the various iglide® materials are used, especially focused at critical points such as those in the disc broom, for example, which is exposed to high shock loads almost constantly while sweeping curbstones, and in the rear lid area which is exposed to strong forces while opening and closing. Additionally, extreme dirt accumulation occurs in both places, which affects all areas.
The particularly wear resistant iglide® L280, as well as iglide® Q for maximum loads, are fitted into the lifting links of the disc broom. For this purpose, iglide® Z, the iglide® material able to stand the highest maximum surface pressure, ensures a strong wear resistance in the hinge and latch of the rear lid. “The dirt is discharged via the rear lid, which gets extremely dirty, and often wet. Since we started to use the plastic bearings, there is no need for welding in case of repair,” Gerhard Gräbel points out.
The issues such as freedom from maintenance and external lubrication, dirt resistance, low wear, and high compressive strength have played a crucial role in the decision in favor of selecting the iglide® plastic plain bearings. After the success of switching the iglide® plastic bearings in the rear lid, a further development of the iglide® Q material was considered for use in areas of the lifting links of the disc broom using the iglide® Q2 material, which is ideal for heavy-duty pivoting applications under extreme operating conditions. Wear-resistant and dimensionally stable at high loads, the Q2 material ensures an extended service life for the mounted sweepers. “Currently, we have a test vehicle running at a customer’s site, whose results have not been fully evaluated,” said Schmeh. “If the calculations are correct, we will switch to this even more wear resistant material in a part of the disc broom.”
The lifting links of the disc broom have been redesigned. Previously, the mechanical engineer relied on bronze or metal bearings with a Teflon coating. “Our goal is to basically just put self-lubricating bearings on this extremely stressed point for all future sweeper models to guarantee our customer’s years of maintenance free operation,” Schmeh explained.
In the igus® test laboratory in Cologne, Germany, countless tests are conducted every year. The focus here is, for example, on material test with high cycle rates, velocities, accelerations, and/or demanding conditions. The components are provided partly by the customer. In addition to the normal surface pressures, the working processes of the disc broom, which pivot in and out continuously in the sweeping operation, are closely scrutinized in this application. Even the microvibrations of the vehicle has been simulated to represent the propelled sweeper.
“The test results demonstrate that the more brittle new material will likely withstand the daily stresses even better in the long term,” the designer assures. “With it, the advantages for the machine operator are obvious. The rugged sweepers are economical in use over time with the simultaneous reduction of maintenance and service costs,” he adds.
Polymer bearings in the rear lid area of the mounted sweeper.
Polymer bearings in the disc broom area of the mounted sweeper.
From left: Gerhard Gräbel, Helmut Schmeh (both Faun Viatec), Thomas Sommerweiß (igus®).
Detailed view of the Faun Viajet 5 Allround mounted sweeper with 5 m³ structural volume.
The collaboration between the two companies worked very well. “We started our search a few years ago for wear-free materials at a fair prices, and made initial attempts with iglide® plastic bearings,” Gerhard Gräbel recalls. “Our local contact is always available, and we attach great importance to that. To preserve the value stability of the sweepers, we also need samples or spare parts at short notice. Now for new or further developments, we think in terms of plastic.”
Even today, more applications for plastic plain bearings are being planned. Metal bearings are, for example, still used in the area of the front broom. Also, they must be lubricated regularly to remain operational over time. The initial tests are already underway with self-lubricating plastic bearings.
Around 250 mounted sweepers are built at the sit in a versatile series production every year. The specifications are clear. “Our customers demand efficient machines – with narrow economic specifications,” concludes Helmut Schmeh. “With our rugged and high quality sweepers of all sizes, a versatile range of cleaning tasks can be covered. In addition, we are sure that over time the self-lubricating bearings are set to be implemented in other places, and will prove themselves and provide the required service life.”