Composite bearings withstand rigors of refuse collection
Heil Europe, Fife, Scotland, has been producing refuse collection vehicles for more than 30 years. Among its product offerings is the Powerlink™ premium collection body, which is available in 16, 19, 22 and 26 m3 sizes for mounting on four-, six- or eight-wheeled chassis. Its full-cycle, swinging-link compaction mechanism produces less friction than conventional channeled compaction systems, directing greater force onto the load. Friction is further reduced by bearings on the packing mechanism of the tailgate, moving joints on the packing cylinders and supporting swing arms. The result is less wear on components and improved service life costs. Initially, Heil used brass/bronze bushings that required regular lubrication. In the early 1990s, the company decided to replace these bushings with 40mm, 50mm and 60mm fibre-reinforced, plastic composite bearings supplied by GGB, formerly Glacier Garlock Bearings, Heilbronn, Germany. “We wanted to get away from the necessity of continuously greasing the pins and bushes,” explained Niall Geoghegan, senior product engineer. “We selected GGB’s GAR-MAX® bearings because of their mechanical properties, namely resistance to shock loads and good friction and wear properties under slow oscillating and rotating speeds.” The Powerlink tailgate, in which the bearings are installed, is designed to withstand dusty, heavily loaded, cyclical operating conditions, eight hours a day, 365 days a year. Packing loads can reach 360kN (81,000 ft. lbs.) at temperatures ranging from -15°C to +40°C. Made of a filament-wound dry bearing material that consists of PTFE, polyester and glass fibre wound and impregnated with epoxy resin, the GAR-MAX bearings could withstand loads of up to 200 MPa. Prototyped on an earlier product developed by Heil in the U.S., they were subsequently used on the Powerlink for the European market. Several years ago, Heil Europe started using GGB’s High-Strength GAR-MAX® bearings, which can withstand even higher compressive loads than its standard GAR-MAX bearings. Advances in the patented GAR-MAX structure and composition provided a 50 percent increase in load-carrying capacity to 300 MPa. “The service life for the bearings is typically two years in the worst case, where the pin operates in the arduous environment of the hopper,” said Geoghegan. He also indicated that the use of the GGB bearings has resulted in less maintenance. “We don’t have to be concerned with forgetting to grease the pins. This reduces the possibility of parts wearing out prematurely, which can result in mechanisms binding and subsequent failure. “The operation of the bearings is appreciably better, giving a longer service life on the pins, bushes and overall packing mechanism,” Geoghegan added. “Extensive trials for these bushes, including shock and loading tests, were conducted in the U.S. prior to their being introduced into the product.” Geoghegan noted that although the initial replacement cost was higher, it was more than offset by the improved performance and service life of the tailgate packing mechanisms. “We’ve been using GGB’s bearings for nearly ten years,” concluded Geoghegan, “and we’ve found them to be ideal for our application.” | 
Powerlink tailgate
Powerlink curved body
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