Which type of mechanical joint allows for rotational motion between two components?

A pin joint is specifically designed to enable rotational motion between two components. It consists of a pin that attaches the two parts but allows for one part to rotate around the pin. This type of joint is fundamental in various mechanical systems, including linkages and frames, where motion and flexibility are necessary for the system to function effectively.

In contrast, a rigid joint, welded joint, and fixed joint are all intended to create a more permanent and immovable connection between components. These joints do not permit rotational movements, which distinguishes the pin joint as the one that allows for the necessary degree of freedom for rotation. Understanding the functions and limitations of these joints is essential in mechanical design and engineering to ensure proper motion and structural integrity in systems.