The LP Survivor Series of disc-pack couplings from R+W America, Bensenville, Ill. transmit torque using friction. A series of bushings press the disc pack together. Precise locating features on the hubs and spacers create a concentric fit. Bolt assemblies get tightened through the hubs, spacers, and bushing to generate the needed clamping pressure across the face of the disc packs to transmit power.

The friction fit eliminates backlash and any problems associated with stress concentrations, all of which can stem from a coupling transmitting torque across the shanks of shoulder bolts. The frictional connection makes the coupling more torsionally stiff and contributes to unlimited service life, provided users don’t exceed its technical limits.

The couplings can transmit from 350 to 20,000 Nm and operate in temperatures from –30 to 280°C. There is also an ATEX version for use in hazardous zones 1/22 and 2/22, as well as one that complies with API-610. The devices work on shafts with bores from 18 to 170 mm.

The couplings compensate for varying combinations of shaft misalignments (axial, lateral, and angular). The total of the three misalignments cannot exceed 100%. So, for example, the packs could handle 20% axial misalignment, 40% lateral misalignment, and 40% angular misalignment between two shafts.