Flexible couplings are a highly critical component when it comes to explosive atmospheres found in automotive paint and cleaning stations, chemical plants, powder mixing areas and numerous other environments. A lack of radially flexible elements in shaft linkage can result in high radial loads being placed on shaft bearings, eventually leading to heat generation and bearing failure, making flexible shaft couplings essential to machine drive design. Even more critical is that the potential for generation of sparks must be eliminated. For use in explosive environments R+W has developed a full range of ATEX certified "explosion proof" couplings in accordance with the European directives, ATEX 95 and ATEX 137. These special couplings are precision machined with a thermally and chemically stable, wear resistant, polyurethane insert press fit between the two for zero backlash. A smooth fit between the insert and the hubs helps the insert to compensate for lateral, angular and axial shaft misalignment. The insert is impregnated with graphite, giving it electrically conductive properties, whereby eliminating the potential for any charges arcing from one hub to the other. Official serialized markings including the part number are required by the directive and are clearly visible on each unit. These precision couplings are available in a variety of mounting configurations, and can include torque overload protection. There are nine total sizes ranging from torque ratings of 2 - 2150 Nm (17 to 19,000 in-lbs). Both English and metric bore diameters are available in a range from 3 - 80 mm (1/8 to 3.125 in) with or without keyways.