Patent ID: 7665980

Claim:
An apparatus for molding with a stack mold having first and second mold assemblies for installation in a clamp unit of an injection molding machine, each mold assembly having mating mold members defining at least one mold cavity, the stack mold having a first mold member connected to a stationary platen of the clamp unit, a third mold member connected to a movable platen of the clamp unit and pair of intermediate mold members comprising a second mold member and a fourth mold member and being interposed between the first mold member and the third mold member so that the first mold member and the second mold member comprise the first mold assembly and the third mold member and fourth mold member comprise the second mold assembly, the apparatus comprising at least one rack and pinion centering device mechanically coupling movement of the third mold member to the intermediate mold members so as to maintain equal separation between mating mold members of the mold assemblies as the mold assemblies are opened and closed, each rack and pinion centering device comprising a pinion rotatably mounted for movement with the intermediate mold members and first and second racks engaging the pinion on opposite sides thereof, one of the racks being attached to the first mold member and the other of the racks being attached to the third mold member and at least one attachment device for attaching a rack to a mold member, the attachment device comprising a base attached to the mold member and at least one releasable clamp member, an end of the rack attached to the mold member by the attachment device being interposed between the base and the releasable clamp members, each releasable clamp member comprising a clamp surface and the end of the rack comprising at least one mating clamp surface and abutting contact of the clamp surfaces with the mating clamp surfaces being effective to restrain longitudinal translation of the rack relative to the base in at least one direction, and the rack being held in a longitudinal location relative to the base within a range of adjustment by the releasable clamp members, whereby the longitudinal location of the rack relative to the mold member is determined within the range of adjustment.