About this 3D model

This model demonstrates the principles of a Kinematic Coupling, which incorporates the concept of degrees of freedom. Two pieces are included, a base and a spider. With one sphere in one groove, two translational degrees of freedom are constrained. With two, two translational degrees and two rotational degrees are constrained. With all three spheres in a groove, the spider is fully constrained. The mechanism is thermally stable, as expansion will simply uniformly expand the grooves. It provides repeatable positioning, and is often used for change-out of low-force mechanisms and manupulators, such as CNC measurement probes and 3d printing head tool changers. FreeCAD files included for modification.