Couplings, as vital components in mechanical transmission systems, serve as critical connectors. They link two shafts to transmit power and coordinate motion, ensuring efficient and stable operation of machinery. In complex and dynamic mechanical environments, couplings must withstand various axial and radial loads while enduring challenges such as impact and vibration. Their ingenious designs, diverse structures, and varied types offer extensive options for different mechanical requirements. Whether rigid, flexible, or composite couplings, each plays an indispensable role. Consequently, the selection and configuration of couplings critically influence the overall performance of mechanical transmission systems.