Clamping a workpiece (in yellow) by hydraulic cylinder through a wedge and two orange levers. Two vertical violet pins are for positioning the workpiece.
In unclamping position orange levers turn back (thanks to their grooves and fixed horizontal violet pins) and give space for mounting or removing the workpiece.
Pink spherical washer is needed to compensate dimension error of the workpiece.
Most parts of the mechanism are cut off half for easy understanding.