Apparatus for injection molding

An apparatus for actuation of split locking nuts of a clamp unit of a two platen injection molding machine, the clamp unit comprising:

• a fixed platen for supporting mold members;
• a movable platen assembly for supporting mating mold members;
• and a plurality of strain rods spanning from the fixed platen through the moveable platen assembly, the movable platen assembly comprising a mold supporting platen for supporting mating mold members, an actuator housing comprising a clamp force actuator, and a plurality of split locking nuts, each split locking nut comprising opposed movable nut halves for releaseably engaging the strain rods, the number of split locking nuts being no less than the number of strain rods, the apparatus comprising:
• a) at least two side blocks fixed to the actuator housing in position relative to opposite sides of each strain rod to be selectably engaged by a split locking nut, the side blocks engaging the opposed mating nut halves of each split locking nut so as to restrain movement thereof bi-directionally to effect opening and closing of the split locking nuts;
• b) connecting rods for connecting nut halves of two split locking nuts so as to define interconnected pairs of split locking nuts, each pair comprising a master split locking nut comprising a nut half driven by an actuator and a slave split locking nut interconnected with the master split locking nut by the connecting rods;
• c) at least one coupling mechanism for coupling motion of a driven nut half of each master split locking nut to the opposed mating nut half of the master split locking nut, wherein each coupling mechanism comprises a pivot arm and two pivot links, the pivot arm being rotatably supported so as to rotate relative to an axis of rotation fixed in position relative to the actuator housing and each pivot link being pivotably connected at one end thereof to an end of the pivot arm and pivotably connected at the distal end thereof to a mating nut half so that rotation of the pivot arm effects rotation and translation of the pivot links to couple translation of the driven nut half to equal and oppositely directed translation of the opposed mating nut half;
• and,
• d) an actuator for each driven nut half for effecting translation of the driven mating nut half toward and away from an associated strain rod, each actuator operably connected between a driven nut half and the actuator housing.