Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Components (hierarchy name)
4. components (objects parts)
5. [components by general context]
6. [joints and joint components]
7. joints (connections)
8. [joints by material joined]
9. metal joints

Anotations

Scope note:

Flexible mechanical joints that allow the axis of one part to be set at an angle to the other by virtue of the design of the two components. One possesses a fixed spherical shell to accommodate the ball-shaped end of the other.