Rigid couplings are mechanical devices used to connect two shafts together, ensuring they rotate in unison without any relative movement. They are designed to transmit torque and maintain alignment between the shafts, which is crucial for the efficient operation of machinery. Common materials for rigid couplings include steel, aluminum, and plastic, depending on the application requirements. These couplings are typically used in applications where precise alignment is necessary, such as in motors, gearboxes, and pumps. Unlike flexible couplings, rigid couplings do not accommodate misalignment, making them suitable for systems where shafts are perfectly aligned. Their simplicity and reliability make them a popular choice in various industrial settings.