Abstract: A pressurized-fluid-operated actuator has two piston surfaces for providing increased output force. The actuator includes a hollow piston that is divided into two inner chambers by a stationary inner dividing wall that is rigidly connected with a cylinder end wall. The piston has an outer diameter that is smaller than the inner diameter of the cylinder, and the piston carries three axially spaced sealing rings that define two axially-spaced annular chambers between the piston and the cylinder. Each of the annular chambers is in fluid communication with a respective port provided in the cylinder wall. Introduction of pressurized fluid into one port causes the fluid pressure to act on a single piston surface to retract the piston and rod, and introduction of pressurized fluid into the other port causes the fluid pressure to act on two axially-spaced piston surfaces to provide an increased output force without increasing the diameter of the cylinder and piston and without increasing the pressure of the fluid.

Abstract: A thermal expansion compensation support and method are used in a hot runner injection mold for maintaining liquid-tight relationships between parts that define a flow passageway. The support includes an annular housing having an annular recess that receives a spring, such as a Belleville washer, and a cover that overlies the annular recess in the housing. The housing and the cover are spring biased from each other to maintain a pressure force on the surfaces that are in contact with the outer faces of each of the cover and of the annular housing. The support imparts a holding force on the several parts of the machine that define the molding material flow passageway to prevent leakage. The method involves holding the parts together at a first holding force level for an initial portion of a warm-up temperature range and holding the parts together at a second holding force level for the remainder of the temperature range.

Abstract: A mold core positioning device includes a cam member carried by a first mold segment that is configured to engage a cam follower carried by a second, cooperating mold segment. The cam follower is provided on a core slide to which an outwardly extending core member, such as a core pin, is connected. The core slide is movable toward and away from a mold cavity to move the core pin into and out of a position within the mold cavity. The cam member includes an extension cam surface and a withdrawal cam surface. The withdrawal cam surface includes a breakaway cam surface that causes slow retraction of the core pin relative to the molded part, and a retraction cam surface that causes more rapid withdrawal of the core slide and core pin after the core pin has been initially separated from the molded part.

Abstract: A valve for controlling the flow of fluent plastic material from an injection molding machine to a mold cavity. The valve includes an axially slidable valve pin that interacts with a material outlet to control flow through the valve selectively. The valve pin is actuated by an eccentric cam arrangement that positively drives the valve pin between positions where it is engaged with or disengaged from the material outlet. The cam acts on the valve pin only in an axial direction to avoid wear occasioned by side loads imposed on a valve pin.

Abstract: A method for mold heater startup and sequencing detects the heater zones associated with greater mass and allows them to heat up before zones of lesser mass, thereby reducing wear of the associated mechanical components and minimizing degradation of plastic material. The zones of smaller mass are kept at minimal temperatures until the zones with greater mass reach a set point. The system is capable of detecting multiple levels of thermal load and provides appropriate sequential startup of the identified thermal loads. The operator may also manually program the system to override certain automated sequences in order to ensure an optimal startup sequence. The sequencing of power application to large heaters also minimizes the peak current draw of the system.

Abstract: A method is disclosed for manufacturing ejector sleeves from tubular stock. In particular, the method includes the following steps or operations: (a) cutting the tube stock to length, (b) enlarging a portion of the inside diameter of the sleeve to provide a clearance diameter, (c) rough-sizing a close-fitting inner diameter, (d) optionally semi-finishing the outside diameter of the sleeve, (e) hardening and straightening the sleeve, (f) final sizing of the outside diameter while maintaining concentricity with the inside diameters, (g) finishing the end face of the sleeve adjacent the close-fitting diameter, (h) final sizing of the close-fitting inner diameter while maintaining concentricity with the outside diameter, (i) forming a head on the sleeve by heating and forging to a predetermined size, (j) optional annealing and refinishing of the head for purposes of hardness or dimensional modification, or improving surface finish.

Abstract: In a thermal plastic molding device, a thermal insulator is provided between the nozzle assembly and the surrounding plates. Preferably, the insulator is a ceramic material, such as zirconia oxide, which is sprayed on in a thin coating, preferably in the range of 0.007-0.012 inches. Alternatively, other nonmetallic coatings can be used, or the insulator can be provided as a ring around the nozzle assembly instead of as a coating. A coating can be applied either to the plate or to the nozzle assembly. A protective coating, preferably a metal, is sprayed or plated over the ceramic insulator.

Abstract: A positive internal latch lock for an injection mold having outer, intermediate, and inner plates movable between open and closed mold positions. The latch lock includes a mechanism for securing the outer and intermediate plates at a predetermined spaced distance when the mold is opened at a first parting line between the outer and intermediate plates. Further, the latch lock provides a mechanism for locking the intermediate and inner plates together until the outer and intermediate plates are secured at the predetermined spaced distance. After the outer and intermediate plates are secured, the intermediate and inner plates are allowed to open at a second parting line.

Abstract: A cam slide retainer for injection molds including an elongated rounded latch groove formed in the cam slide and a corresponding lock in the core retaining plate. The slide retainer is simple to install since the body portion of the lock is circular and is installed by press fitting into the core retaining plate from the back. A shoulder on the body portion is received in a counterbore to properly position the elongated rounded lock plunger head to extend above the inside surface of the core retaining plate. A flat key surface on the shoulder properly aligns the plunger head to extend transverse to the direction of the slide movement. The elongated rounded groove in the cam slide is positioned to matingly receive the elongated rounded plunger head when the slide is moved to the position away from the molded part to releasably lock the cam slide in position.