protected flange coupling

Couplings are used to join two shafts so that they act as a single unit during rotation and power can be transmitted from one shaft to the other. The protected flanged coupling is a rigid shaft coupling, the axes of the shafts being collinear.In this rigid coupling, the bolt heads and nuts are located in the annular recesses provided on the flanges and so are not exposed. Hence, the name protected flanged coupling.