Which of the following is a common flexible coupling type?

• A. Rigid coupling
• B. Jaw coupling (flexible coupling)
• C. Sleeve coupling
• D. Magnetic coupling

Answer: (B)

Flexible couplings transmit torque while accommodating some misalignment and damping vibrations. The jaw coupling is a classic example because it uses two hubs with interlocking jaw profiles and a resilient elastomer spider between them. That elastomer provides the necessary give, allowing small angular, parallel, and axial misalignments without creating large binding stresses in the shafts or bearings. It also cushions shocks and reduces noise, making it robust and cost-effective for many light- to moderate-duty applications.

Rigid couplings, in contrast, have no flexibility, so any misalignment transfers directly into the system, which can lead to bearing or shaft stresses. Sleeve couplings are essentially rigid as well, offering a simple connection with little to no misalignment allowance. Magnetic couplings can tolerate some misalignment and are useful in sealed or hazardous-fluid applications, but they’re not the typical, broadly used flexible option for general mechanical power transmission.