Abstract: An injection molding machine can include a base, a stationary platen fixed to the base for holding a first mold section and a moving platen for holding a second mold section. The moving platen can be slidably supported on a platen slide surface fixed to the base. The injection molding machine can also include a stack mold carriage for holding a mold center section. An actuator can be coupled to the stack mold carriage for translating the stack mold carriage along the machine axis towards and away from the stationary platen, the actuator comprising a driven member coupled to a carriage connection portion. The carriage connection portion can transfer motion from the driven member to translation of the stack mold carriage. The carriage connection portion can be joined to the stack mold carriage at an elevation below the platen slide surface.

Abstract: An injection drive unit includes a hollow cylindrical casing rotatably supported by a housing, the cylindrical casing having an axis and a front end and a back end spaced apart along the axis; a piston in the cylindrical casing, the piston axially slidable relative to the cylindrical casing along the axis between advanced and retracted positions, and the piston rotationally locked with the cylindrical casing to rotate therewith; and a cylinder cap generally closing off the back end of the cylindrical casing and providing a first pressure chamber between the piston and the cylinder cap, the cylinder cap including a stationary part affixed to the housing and a rotary part affixed to the cylindrical casing, at least the stationary part providing a stationary end face opposed to the piston and against which fluid in the first pressure chamber bears when pressurized.

Abstract: A combination comprises first and second platens of an injection molding machine, a tie bar extending from the second platen to the first platen, and a locking device for releasably securing together the tie bar and the first platen.

Abstract: A method for injection molding comprises pre-positioning a clamp piston within a cylinder housing to a datum position axially intermediate a clamping position and an unclamped position, the clamp piston affixed to a tie bar, the clamp piston and cylinder housing cooperating to provide a clamp chamber and an unclamp chamber in a clamp cylinder housing on axially opposite sides of the clamp piston for urging the clamp piston towards the clamping and unclamped positions, respectively, when pressurized. Pre-positioning the clamp piston can include leaving a positioning gap between portions of a mold before releasably locking a tie bar to one of the moving or stationary platens, and then advancing the moving platen to substantially close the positioning gap after the releasable locking has been completed.

Abstract: A platen for supporting a mold portion in an injection molding machine comprises a mounting plate having a front face for supporting a mold portion, and a rear face spaced apart from the front face. The mounting plate has vertically spaced apart top and bottom horizontal margins, and horizontally spaced apart vertical margins. The vertical and horizontal margins generally intersect at four respective corners of the mounting plate. Four tie bar connection bosses are affixed to the rear face. Each tie bar connection boss is positioned at one of the corners of the mounting plate. Four peripheral walls extend rearwardly from the rear face of the mounting plate for transferring a clamping load from the tie bar connection bosses to the mounting plate. Each peripheral wall has a length parallel to the front face and has opposed ends joined to respective adjacent ones of the tie bar connection bosses.

Abstract: An injection drive unit includes a hollow cylindrical casing rotatably supported by a housing, the cylindrical casing having an axis and a front end and a back end spaced apart along the axis; a piston in the cylindrical casing, the piston axially slidable relative to the cylindrical casing along the axis between advanced and retracted positions, and the piston rotationally locked with the cylindrical casing to rotate therewith; and a cylinder cap generally closing off the back end of the cylindrical casing and providing a first pressure chamber between the piston and the cylinder cap, the cylinder cap including a stationary part affixed to the housing and a rotary part affixed to the cylindrical casing, at least the stationary part providing a stationary end face opposed to the piston and against which fluid in the first pressure chamber bears when pressurized.