Coupling devices are mechanical components used to connect two shafts together, allowing them to transmit power and motion. They help in aligning the shafts and can accommodate misalignment, reducing wear and tear on machinery. Common types of coupling devices include flexible couplings, rigid couplings, and universal joints. These devices are essential in various applications, such as in automotive engines, industrial machinery, and pumps. By ensuring a reliable connection between shafts, coupling devices enhance the efficiency and longevity of mechanical systems, making them crucial in engineering and manufacturing processes.