This mechanism converts the rotation of a spherical ring into both orbital and self-rotation of a guided follower. As the yellow ring turns, the red arm is constrained by the curved inner surface, causing it to sweep around the ring while also spinning around its own axis in response to the geometry of the track.

Components — Yellow spherical ring, red follower arm, red spherical roller (ball), gray mounting block, central support post, and the base frame.

How it works — When the yellow ring rotates, the red follower is carried along the ring¡¯s curved inner path. Because the red follower contains a rolling ball that stays in contact with the ring¡¯s spherical surface, its motion is not simply translation; the ball forces the follower to rotate about its own axis as it travels. The curvature of the ring ensures that the follower¡¯s position and orientation change together, turning a single driving rotation into a combined sweeping and self-spinning motion.

Applications — Articulated camera gimbals, compact positioning joints, orientation-guided motion stages, robotic fingertip mechanisms, and devices that require synchronized path travel and self-rotation.

Why it matters — This spherical-track arrangement produces complex, coordinated motion using only a ring and a follower¡ªno multi-link chains or bearings required. The resulting motion is smooth, predictable, and compact, ideal for applications where controlled orientation is as important as position.