Which statement best describes the difference between flexible and rigid couplings?

Which statement best describes the difference between flexible and rigid couplings?

• A. Flexible couplings tolerate misalignment; rigid couplings do not.
• B. Flexible couplings are always stronger than rigid.
• C. Rigid couplings absorb more vibration than flexible.
• D. Flexible couplings cannot transmit torque.

Answer: (A)

Flexible couplings are designed to tolerate misalignment between shafts, allowing some angular, parallel, or small axial displacement while still transmitting torque. This elasticity helps damp vibrations and shocks, protecting bearings and gears and keeping the system running smoothly even if the shafts aren’t perfectly aligned. Rigid couplings, on the other hand, keep the two shafts in fixed alignment with little to no deflection. They transmit torque effectively, but any misalignment is resisted as bending loads on the shafts and bearings, which can lead to wear or failure if alignment isn’t exact. So, the best description is that flexible couplings tolerate misalignment while rigid couplings do not. The other statements aren’t correct because strength depends on design, rigid couplings don’t inherently absorb more vibration, and flexible couplings do transmit torque.

Flexible couplings are designed to tolerate misalignment between shafts, allowing some angular, parallel, or small axial displacement while still transmitting torque. This elasticity helps damp vibrations and shocks, protecting bearings and gears and keeping the system running smoothly even if the shafts aren’t perfectly aligned.

Rigid couplings, on the other hand, keep the two shafts in fixed alignment with little to no deflection. They transmit torque effectively, but any misalignment is resisted as bending loads on the shafts and bearings, which can lead to wear or failure if alignment isn’t exact.

So, the best description is that flexible couplings tolerate misalignment while rigid couplings do not. The other statements aren’t correct because strength depends on design, rigid couplings don’t inherently absorb more vibration, and flexible couplings do transmit torque.