What is the function of a flexible coupling in a drive system?

• A. To absorb minor misalignment, endfloat, and shock while transmitting torque.
• B. To increase misalignment.
• C. To eliminate vibration completely.
• D. To couple only rigidly with no movement.

Answer: (A)

Flexible couplings are used to connect two shafts in a drive system while allowing slight movements between them. They absorb minor angular and parallel misalignment, axial endfloat (shaft end play), and dynamic shocks, all while transmitting torque from one shaft to the other. This flexibility helps keep bearings and gears from experiencing excessive loads and reduces vibration and wear, improving overall reliability.

They don’t purposefully increase misalignment, and they don’t eliminate vibration completely—vibration is reduced but not entirely removed. They also aren’t meant to rigidly couple shafts with no movement at all.