Apparatus for actuation of split locking nuts of a two platen injection molding machine. Each split locking nut has opposed mating nut halves movable in translation relative to a strain rod therebetween to selectably engage the strain rod. Mating nut halves of two split locking nuts are interconnected by connecting rods to define a pair of split nuts: a master split locking nut driven by an actuator; and a slave split locking nut to which motion is transferred by the connecting rods. Motion of a driven nut half of each master split locking nut is coupled to the opposed mating nut half by at least one coupling mechanism, each comprising a pivot arm and two pivot links interposed between the pivot arm and the opposed mating nut halves whereby translation of a driven nut half is coupled to effect equal and opposite translation of the opposed mating nut half.