What is a polhem joint?

A Polhem joint, also known as a spherical joint or universal joint, is a mechanical device that allows for rotational movement in multiple directions. It consists of two parts: a spherical ball and a socket, enabling components to pivot freely while maintaining a connection. This type of joint is commonly used in robotics, machinery, and various applications where flexibility and range of motion are needed. Its design helps accommodate misalignment between connected parts.