What is the primary use of a universal joint?

The primary use of a universal joint is to compensate for misalignment of shafts by allowing a rotational connection between them. Specifically, a universal joint is designed to accommodate angular misalignment, typically up to 20 degrees. This flexibility ensures that power can be transmitted smoothly between shafts that are not perfectly aligned, which is crucial in various mechanical systems, such as those found in automotive drive trains and machinery.

In contrast, options that suggest a fixed length or limited alignment do not accurately reflect the functionality of a universal joint. A universal joint is not meant for connecting shafts at a fixed length or for maintaining strict alignment; rather, it effectively manages the challenges posed by angular discrepancies between connected shafts. Its design facilitates smooth operation despite these misalignments, making it an essential component in applications where flexibility and range of motion are necessary.