Gear couplings transmit the highest amount of torque and the highest amount of torque in the smallest diameter of any flexible coupling.
Each coupling consists of two hubs with crowned external gear teeth. The hubs mesh with two internally splined flanged sleeves that are bolted together. Gear couplings accommodate angular and axial misalignment by the rocking and sliding of the crowned gear teeth against the mating sleeve teeth. Parallel misalignment is accommodated by having two adjacent hub/sleeve flex points. Gear couplings require periodic lubrication depending on the application.