Yellow rack is connected to the movable half mold.
When the movable half mold moves, the rack pinion drive, two gear drives and the screw drive (blue screw and violet fixed nut) make blue shaft carrying the pink thread core rotate and translate.
Thus the thread core is inserted into or removed from the plastic injection part (not shown).
The pink gear has sliding key joint with the blue screw.
Thread leads of thread core and the blue screw must be equal.
In consideration of short stroke of the movable half mold, two gear drives are used for increasing revolutions of the blue screw.