What should be used when precise alignment is not feasible?

When precise alignment is not feasible, a flexible coupling is the appropriate choice. Flexible couplings are designed to accommodate misalignment between shafts, whether that misalignment is angular, parallel, or axial. They can absorb vibrations and reduce the transmission of shock loads, making them ideal for situations where perfect alignment cannot be achieved due to physical constraints or operational variations.

In contrast, rigid couplings require precise alignment to function effectively, as they do not allow for any misalignment and can transmit misalignment issues directly, leading to increased wear, vibration, and potential failure. Chain drives and direct drives also have their limitations regarding alignment. Chain drives can tolerate some misalignment, but they typically are used in applications where flexibility isn’t a primary concern. Direct drives are meant to have a close and direct connection without any coupling, making them unsuitable when misalignment exists. Thus, the use of flexible couplings provides the necessary adaptability to ensure continuous operation despite alignment challenges.