Turn green lever to clamp or release yellow workpiece.
Blue floating cam ensures the equalizing clamp of three brown jaws for the workpiece.
The green lever is pivoted on violet stationary center shaft.
The orange part has prismatic joint with the lever.
The cam has prismatic joint with the orange part.
The ridge and the groove on the orange part are perpendicular to each other.
So the cam and orange part can move in horizontal plane in relation with the center shaft.
The jaws may not move synchonically but at the end they clamp tightly the workpiece that is centered on upper surface of the fixture base (equalizing clamping).