Most couplings can be divided into one of two types, rigid and flexible. Rigid couplings are used for applications that require proper alignment, while flexible couplings, such as beam couplings, are suitable for applications where there is some acceptable misalignment.

Beam couplings, sometimes called screw couplings, are made from a piece of material that is made flexible by removing material in a helical pattern along its length. Like all couplings, the purpose of beam couplings is to transfer torque between two shafts, but unlike rigid couplings, beam couplings can accommodate angular misalignment, parallel misalignment of one shaft relative to the other even axial movement. Beam couplings also differ from other coupling types in that their one-piece construction prevents the backlash typically encountered with couplings made of multiple parts.