The BK3 couplings from R+W America are designed for high torque servo gearboxes. They feature double-walled stainless steel bellows that absorb parallel, angular and axial shaft misalignment. The BK3 has high torsional stiffness to contrast its low moment of inertial, so it handles quickly indexing and reversing servo applications.

These couplings are manufactured with at tapered conical clamping component, which allows for high shaft clamping forces without keys, compared to other hub designs. For help in tight spaces, the BK3 has disassembly screws.           

Clamping sleeves are custom bored on each side for shaft diamters from 10 to 80 mm (0.39 to 3.13 inches). They are available in sizes for torque capacities from 15 to 10,000 Nm (133 to 88,500 in-lbs.).