What type of movement do flexible couplings permit?

Flexible couplings are designed to accommodate slight misalignments between shafts in a mechanical system. They allow for both axial and angular movements, which means they can absorb some variations in alignment and prevent stress on connected components.

Choosing axial movement as the correct answer highlights a key feature of flexible couplings: their ability to allow movement along the axis of the shafts they join. This is particularly important in applications where thermal expansion or contraction might occur, or when other forces could pull or push the shafts apart or together.

While radial, torsional, and rotational movements are aspects of how different couplings and mechanical systems might operate, flexible couplings specifically enable axial movements along with an ability to compensate for angular misalignment, which is central to their function. Understanding this characteristic helps in selecting the right coupling for specific applications where misalignment may occur.