This invention relates generally to molding apparatus and associated methods. More specifically, although not exclusively, this invention relates to mold stacks, mold assemblies, molds, molding systems for molding preforms and other articles, for example tubular articles, and to associated methods.

BACKGROUND OF THE INVENTION

Molding is a process by virtue of which a molded article can be formed from molding material, such as a plastics material, by using a molding system, such as an injection molding system or a compression molding system. Various molded articles can be formed by using such molding processes including, for example, preforms which can be formed from polyethylene terephthalate (PET) material. Such preforms are capable of being subsequently blown into a container, for example a beverage container, bottle, can or the like.

As an illustration, injection molding of preforms involves heating PET material (or other suitable molding material for that matter) to a homogeneous molten state and injecting, under pressure, the so-melted material into a molding cavity defined, at least in part, by a female cavity piece and a male core piece. Typically, the female cavity piece is mounted to a cavity plate and the male core piece is mounted to a core plate of a mold. The cavity plate and the core plate are urged together and are held together by clamp force, the clamp force being sufficient to keep the cavity and the core pieces together against the pressure of the inj ected material . The molding cavity has a shape that substantially corresponds to a final cold-state shape of the molded article to be molded. The so-injected material is then cooled to a temperature sufficient to enable removal of the so-formed molded article from the molding cavity. When cooled, the molded article shrinks inside of the molding cavity and, as such, when the cavity and core plates are urged apart, the molded article tends to remain associated with the core piece.

Accordingly, by urging the core plate away from the cavity plate, the molded article can be subsequently demolded by ejecting it off the core piece. Ejection structures are known to assist in

removing the molded articles from the core halves. Examples of the ejection structures include stripper plates, stripper rings and neck rings, ejector pins, etc.

When dealing with molding a preform that is capable of being subsequently blown into a beverage container, one consideration that needs to be addressed is forming a so-called "neck region" . Typically and as an example, the neck region includes (i) engaging features, such as threads (or other suitable structure), for accepting and retaining a closure assembly (ex. a bottle cap), and (ii) an anti-pilferage assembly to cooperate, for example, with the closure assembly to indicate whether the end product (i.e. the beverage container that has been filled with a beverage and shipped to a store) has been tampered with in any way. The neck region may comprise other additional elements used for various purposes, such as to cooperate with parts of the molding system (ex. a support ledge, etc.). As is appreciated in the art, the neck region cannot be formed easily by using the cavity and core halves. Traditionally, split mold inserts (sometimes referred to by those skilled in the art as "neck ring") have been used to form the neck region.

A typical molding insert stack assembly that can be arranged (in use) within a molding machine includes a split mold insert pair that, together with a mold cavity insert, a gate insert and a core insert, defines a molding cavity. Molding material can be injected into the molding cavity from a source of molding material via a receptacle or port in the gate insert to form a molded article. In order to facilitate forming of the neck region of the molded article and subsequent removal of the molded article therefrom, the split mold insert pair comprises a pair of complementary split mold inserts that are mounted on adjacent slides of a slide pair. The slide pair is slidably mounted on a top surface of a stripper plate.

As commonly known, the stripper plate is configured to be movable relative to the cavity insert and the core insert, when the mold is arranged in an open configuration. As such, the slide pair, and the complementary split mold inserts mounted thereon, can be driven laterally, via a cam arrangement or any other suitable known means, for the release of the molded article from the molding cavity. One of the functions performed by the split mold insert pair is to assist in ejecting the molded article off the core insert by "sliding" the molded article off the core insert.

SUMMARY OF THE INVENTION

The present invention seeks to provide an alternative mold assembly, preferably one which is more versatile and with greater modularity, for molding articles, specifically but not exclusively tubular articles such as preforms. This invention is directed, in particular but not exclusively, to mold stacks, molds, mold assemblies, molding systems and associated methods. In the case of tubular articles such as preforms, the articles may have a base portion at a closed end, a neck finish at an open end and a body portion therebetween. The neck finish may include one or more radial flanges, which may extend outwardly. The neck finish may include engaging features, such as threads or a snap fit finish. The preform and/or neck finish may comprise any one or more other features described above in relation to known preform designs. In addition, any of the foregoing features described in relation to known mold stacks, molds and molding systems may be incorporated within mold stacks, molds and molding systems according to the invention, insofar as they are consistent with the disclosure herein.

According to a first broad aspect of the present invention, there is provided a mold assembly, e.g. a cavity plate assembly, for a mold, e.g. a preform mold, the assembly comprising a cavity plate having one or more seats and one or more cavity inserts mounted to a front face of the cavity plate and in communication with a respective seat, wherein the or each cavity insert comprises a molding cavity or molding surface along its length at least two thirds of which extends beyond the cavity plate.

The cavity insert may comprise a taper at a first end and/or a mounting face at or adjacent a second end, e.g. for mounting the cavity insert to a cavity plate. At least two thirds of the molding cavity or molding surface may be between the taper and the mounting face.

Another aspect of the invention provides a cavity insert, e.g. a preform cavity insert, comprising a taper at a first end, a molding cavity or molding surface along its length, a mounting face at or adjacent a second end for mounting the cavity insert to a cavity plate, wherein at least two thirds of the molding cavity or molding surface is between the taper and the mounting face.

At least 70% or 75% or 80% or 85% or 90% of the molding cavity or molding surface may extend beyond the cavity plate. At least 70% or 75% or 80% or 85% or 90% of the molding cavity or molding surface may be between the taper and the mounting face.

The cavity plate may comprise a rear face, e.g. for mounting to a melt distributor. The cavity plate may comprise a depth described from the front face to the rear face. The cavity plate may comprise a cooling channel, which may be described therein. The cooling channel may have a depth that is at least 15% of the plate depth.

Another aspect of the invention provides a mold assembly, e g. a cavity plate assembly, for a mold, e.g. a preform mold, the assembly comprising a cavity plate having one or more seats and one or more cavity inserts mounted to a front face of the cavity plate and in communication with a respective seat, wherein the cavity plate comprises a rear face for mounting to a melt distributor, a depth described from the front face to the rear face and a cooling channel described therein which has a depth that is at least 15% of the plate depth.

Another aspect of the invention provides a cavity plate, e.g. a preform cavity plate, comprising a cooling channel described therein, a front face with an array of seats in fluid communication with the cooling channel for connection with respective cavity inserts, a rear face for mounting to a melt distributor and a depth described from the front face to the rear face, wherein the cooling channel has a depth that is at least 15% of the plate depth.

The cooling channel depth may be at least 20% or 25% or 30% or 40% or 45% or 50% of the plate depth.

The or each cavity insert may comprise a body, which may include the mounting face, e.g. at or adjacent one of its ends. The or each cavity insert may comprise a spigot, which may project from the mounting face. The spigot may be received or receivable in a respective seat of the cavity plate, e.g. such that the mounting face abuts the front face of the cavity plate. The spigot may comprise a cooling channel inlet and/or a cooling channel outlet. The cooling channel inlet and/or the cooling channel outlet may be in fluid communication with, or suitable or configured for fluid connection with, a cooling channel opening in the seat of the cavity plate.

Another aspect of the invention provides a mold assembly, e.g. a cavity plate assembly, for a mold, e.g. a preform mold, the assembly comprising a cavity plate having one or more seats and one or more cavity inserts mounted to a front face of the cavity plate and in communication with a respective seat, wherein the or each cavity insert comprises a body with a mounting face and a spigot projecting from the mounting face and received in a respective seat of the cavity plate such that the mounting face abuts the front face of the cavity plate, each spigot preferably comprising a cooling channel inlet and a cooling channel outlet both of which are in fluid communication with respective cooling channel openings in the seat of the cavity plate.

Another aspect of the invention provides a cavity insert, e.g. a preform cavity insert, comprising a molding cavity or molding surface along its length, a body with a mounting face at or adjacent one of its ends for mounting the cavity insert to a cavity plate and a spigot projecting from the mounting face for receipt within a seat of a cavity plate, wherein the spigot preferably comprises a cooling channel inlet and a cooling channel outlet for fluid connection with respective cooling channel openings in the seat of the cavity plate.

The cooling channel openings in each seat may be located at substantially the same depth. The cooling channel openings in each seat may be on opposite sides thereof. The cooling channel inlet may be on a first side of the spigot and/or of the cavity insert. The cooling channel outlet may be on a second side of the spigot and/or of the cavity insert, which may be opposite the first side.

The cavity insert may comprise one or more cooling channels, which may extend along or parallel and/or adjacent the molding cavity or molding surface. The one or more cooling channels may comprise one or more axial channels, which may extend along or parallel and/or adjacent the molding cavity or molding surface. The one or more cooling channels may comprise one or more transverse channels, which may extend about or around and/or adjacent the molding cavity or molding surface. The axial channel(s) may comprise a plurality of axial channels, which may be connected together by the transverse channel(s). The transverse channel(s) may extend tangentially with respect to the molding cavity or molding surface and/or may be spaced therefrom. The transverse channel(s) may intersect some or all of the axial channels, for example to fluidly connect them.

The cavity insert may comprise a first cooling circuit, which may be in fluid communication with the cooling channel inlet and/or may extend along the first side of the cavity insert. The first cooling circuit may comprise one or more, e g. a plurality of, the axial channels. The cavity insert may comprise a second cooling channel circuit, which may be in fluid communication with the cooling channel outlet and/or may extend along the second side of the cavity insert. The first cooling circuit may comprise one or more, e.g. a plurality of, the axial channels.

The mounting face may be at or adjacent a first end of the body and the body may comprise a second end. The first cooling circuit may be fluidly connected to the second cooling circuit at the second end of the body, e.g. such that cooling fluid entering, in use, into the cooling channel inlet flows through the first cooling circuit toward the second end, into and through the second cooling circuit back toward the first end and out of the cooling channel outlet.

The body may be substantially cylindrical, for example with a pair of flat sides, e.g. for reducing the minimum pitch between adjacent cavity inserts. The molding cavity or molding surface may be substantially cylindrical. The spigot may be substantially cylindrical. The spigot may comprise a gate insert seat, e.g. for receiving a gate insert.

The assembly may comprise a gate insert, which may be received within the or a seat in the spigot of at least one or each cavity insert.

Another aspect of the invention provides a cavity assembly comprising a cavity insert, e.g. as described above, and a gate insert received within the gate insert seat.

The or each gate insert may comprise a cooling channel, which may be in fluid communication with the cooling channel inlet of the spigot, e.g. for receiving cooling fluid therefrom. The cooling channel may be in fluid communication with the cooling channel outlet of the spigot, e.g. for supplying cooling fluid thereto. The assembly may comprise a diverter, e.g. for diverting, in use, cooling fluid from the cooling channel of the gate insert and/or into one or more cooling channels of the cavity insert. The diverter may separate the cooling channel of the gate insert into two segments.

A first of the cooling channel segments may provide a fluid connection between the cooling channel inlet of the spigot and one or more cooling channels, e.g. axial cooling channels, of the cavity insert. The first cooling channel segment may provide a fluid connection between the cooling channel inlet of the spigot and the first cooling circuit of the cavity insert. A second of the cooling channel segments may provide a fluid connection between the cooling channel outlet of the spigot and the cooling channels, e.g. axial cooling channels, of the cavity insert. The second cooling channel segment may provide a fluid connection between the cooling channel outlet of the spigot and the second cooling circuit of the cavity insert.

The cooling channel of the gate insert may comprise a circumferential cooling groove, which may cooperate with a facing surface of the gate insert seat of the spigot. The diverter may comprise a projection or pin, which may extend from the spigot into the cooling groove. The diverter a pair of opposed pins, which may be received within the cooling groove, e.g. to the first and second cooling channel segments.

The assembly may comprise a bypass channel, which may be described between the pins and the gate insert. The bypass channel may allow restricted flow from the first cooling channel segment to, e.g. directly to, the second cooling channel segment. The bypass channel may be provided by a circumferential recess, which may be in the circumferential cooling groove of the gate insert. The circumferential cooling groove of the gate insert may comprise a primary groove. The bypass channel may be provided at least in part by a secondary groove, which may be in the base of the primary groove. Additionally or alternatively, the bypass channel may be provided by a hole or cutaway in one or both of the projections or pins.

The or each projection or pin may be threadedly engaged in a hole through the spigot of the cavity insert. The or each projection or pin may serve as a retaining means or pin, e.g. for retaining the cavity insert within the seat of the spigot. At least part of the pin may comprise an external thread. At least part of the pin may comprise a featureless and/or smooth circumferential surface. In some examples, part of the pin has an external thread and part of the pin has a featureless and/or smooth circumferential surface.

The cavity insert may comprise a pair of threaded holes, which may be through the spigot, e.g. for threadedly receiving retaining pins extending into the gate insert seat. The threaded holes and/or the cooling channel inlet and outlet may be spaced equally about the periphery of the spigot. The threaded holes may be between the cooling channel inlet and outlet and/or may extend orthogonally or perpendicular with respect thereto.

The or each seat may comprise a first seat portion, which may extend from the front face, and/or a second seat portion, which may extend from the rear face. The first seat portion may be larger or smaller than the second seat portion, e.g. with a shoulder or transition described therebetween. The spigot of the cavity insert may be received in the first seat portion and/or may abut the shoulder or transition. Alternatively, the gate insert may abut the shoulder or transition. The front face may comprise a mounting interface, e.g. adjacent each seat, to which a cavity insert is mounted, in use, such that a spigot thereof is received within the first seat portion and/or abuts against the shoulder.

Another aspect of the invention provides a cavity plate, e g. a preform cavity plate, comprising a front face, a rear face and an array of seats with cooling channel openings therein, each seat comprising a first seat portion extending from the front face and a second seat portion extending from the rear face, the first seat portion being larger than the second seat portion with a shoulder or transition described therebetween, wherein the front face comprises a mounting interface adjacent each seat to which a cavity insert is mounted, in use, such that a spigot thereof is received within the first seat portion, e g. and abuts against the shoulder.

The or each gate insert may extend from the spigot and/or into the or a respective second seat portion. The or each gate insert may include a seat or recess, e.g. for receiving a gate pad or nozzle tip of a melt distributor. The recess may comprise a gate pad recess, e.g. for receiving an outlet end of a gate pad mounted to a melt distributor. The gate pad recess may be tapered. The gate pad recess may be conical or frustoconical, for example with a flat base. Alternatively, the recess may comprise a nozzle tip seat, e.g. for receiving a nozzle tip of a melt distributor.

Another aspect of the invention provides a preform mold assembly comprising a melt distributor and a cavity plate assembly, e.g. as described above, wherein the melt distributor comprises one or more gate pads mounted thereto each having an outlet end received in a corresponding gate pad recess of the cavity plate assembly.

The gate insert may comprise a body, which may be substantially cylindrical. The gate insert or body may describe the seat or recess, e.g in a first end of the body. The gate insert may comprise a molding cavity portion, e.g. in a second end of the body. The gate insert may comprise a gate, which may join the seat or recess to the molding cavity portion. The gate may be central and/or may extend from the flat base of the gate pad recess. The gate insert may comprise a cooling groove around the gate and a bypass groove recessed therein. The cooling groove may describe a cooling channel within which is received, in use, a pair of diverters that separate the channel into inlet and outlet channel segments and/or which describe, with the bypass groove, bypass channel segments that allow restricted flow between the inlet and outlet channel segment.

Another aspect of the invention provides a gate insert, e.g. a preform gate insert, comprising a cylindrical body that describes: a gate pad or nozzle seat in a first end of the cylindrical body; a molding cavity portion in a second end of the cylindrical body; a gate joining the gate pad or nozzle seat to the molding cavity portion; and a cooling groove around the gate and having a bypass groove recessed therein; wherein the cooling groove describes a cooling channel within which is received, in use, a pair of diverters that separate the channel into inlet and outlet channel segments and which describe, with the bypass groove, bypass channel segments that allow restricted flow between the inlet and outlet channel segment.

The cylindrical body may comprise a first diameter, which may surround at least part of the gate pad or nozzle seat. The body may comprise a second diameter, which may surround at least part of the molding cavity portion. The second diameter may be smaller than the first diameter. The cooling groove may be located at or adjacent the transition between the first diameter and the second diameter, e.g. thereby providing a necked intermediate portion.

The first end may comprise the first diameter and the second end may comprise the second diameter. Alternatively, the first end may comprise a third diameter, which may be larger than the first diameter, e.g. with a shoulder described therebetween against which the spigot of the cavity insert may abut. The first diameter may be between the second and third diameters.

Another aspect of the invention provides a gate insert, e.g. a preform gate insert, comprising a cylindrical body that describes: a recess or seat, e.g. a gate pad or nozzle seat, in a first end of the cylindrical body, e.g. for receiving a gate pad or nozzle tip; a molding cavity portion in a second end of the cylindrical body; and a gate joining the gate pad or nozzle seat to the molding cavity portion; wherein the recess or seat in the first end is tapered at an included angle of between 10 and 60 degrees, for example between 20 and 50 degrees, 25 and 45 degrees or between 30 and 40 degrees.

Another aspect of the invention provides a preform gate insert, e.g. as described above, in combination with a gate pad, the gate pad comprising a substantially cylindrical body describing a nozzle seat and having a first, threaded end, a second, outlet end for receipt in the gate pad or nozzle seat and a flange between the first and second ends. The flange may comprise one or more flats, e.g. for engaging an

installation tool. The flange may comprise a polygonal, e.g. a hexagonal, shape in plan or cross-section.

The outlet end of the gate pad may be tapered. The outlet end of the gate pad may be conical or substantially frustoconical. The outlet end may be tapered at an included angle of between 10 and 60 degrees, for example between 20 and 50, preferably between 25 and 45 degrees and most preferably between 30 and 40 degrees.

The body may be hollow. The body may comprise a shoulder, which may be between the flange and the first end. The flange and/or the shoulder may protrude outwardly. The nozzle seat may extend from the first end and/or terminate in the second end of the gate pad, e.g. at a gate. The gate may be central and/or cylindrical and/or may form an aperture through a tip of the outlet end.

Another aspect of the invention provides a gate pad comprising a substantially cylindrical body describing a nozzle seat and having a first, threaded end, a second, outlet end for receipt in a seat, e.g. a gate pad or nozzle seat, or recess of a gate insert, wherein the second, outlet end is tapered at an included angle of between 10 and 60 degrees, for example between 20 and 50 degrees, 25 and 45 degrees or between 30 and 40 degrees.

The mold assembly may comprise a melt distributor. The melt distributor may comprise one or more nozzles and/or one or more holes, which may receive at least part of a respective one of the nozzles. The or each hole may comprise a threaded portion and/or a pocket, e.g. an enlarged pocket. The pocket may be located at an end of the hole and/or may extend from a cavity plate facing surface of the melt distributor.

The threaded end of the gate pad may be received within, and/or be in threaded engagement with, one of the holes of the melt distributor, e.g. such that a nozzle tip extends into the nozzle seat. The shoulder of the gate pad may be received in the pocket. The shoulder may be annular and/or may be sized to provide a tight fit with the pocket, e.g. to maintain alignment of the gate pad relative to the melt distributor and/or nozzle.

The melt distributor may be mounted to the cavity plate, e.g. such that the outlet end of the gate pad is received within the gate pad receiving portion of the gate insert and/or such that the gate of the gate insert and the gate of the gate pad are aligned. The combined depth of the spigot, gate insert and flange may be less than that of the cavity plate.

At least one or each seat of the cavity plate may be fluidly connected to the cooling channel of the cavity insert via a cooling channel inlet, which may be on a first side of the seat, and/or a cooling channel outlet, which may be at substantially the same depth as the cooling channel inlet and/or on a second side of the seat, which may be opposite the first side.

Another aspect of the invention provides a cavity plate, e.g. a preform cavity plate, comprising cooling channels described therein, a front face with an array of seats in fluid communication with the cooling channels for connection with respective cavity inserts, a rear face for mounting to a melt distributor and a depth described from the front face to the rear face, wherein each seat comprises a pair of cooling channel openings fluidly connected to the cooling channels at substantially the same depth.

Another aspect of the invention provides a mold, e.g. a preform mold, comprising an assembly or cavity plate as described above. The mold may comprise an injection mold, e.g. a preform injection mold.

Another aspect of the invention provides a molding system comprising a mold as described above. The molding system may comprise one or more of a melt distributor, an injection molding machine, a material supply system and a part removal and/or post mold cooling apparatus.

Another aspect of the invention provides a computer program element comprising and/or describing and/or defining a three-dimensional design for use with a simulation means or a three-dimensional additive or subtractive manufacturing means or device, e.g. a three-dimensional printer or CNC machine, the three-dimensional design comprising one or more mold components described above.

Another aspect of the invention provides a method of assembling an assembly as described above. The method may comprise one or more of inserting the gate insert into the gate insert seat of the cavity insert, inserting the retaining pin(s) into the threaded hole(s) of the spigot of the cavity insert and/or inserting the spigot of at least one of the cavity inserts into one of the seats in the cavity plate. Other steps and features of the method will be apparent to the skilled person.

Another aspect of the invention provides a method of molding articles. The method may comprise the use of one of the aforementioned mold stacks, molds, mold assemblies or molding systems. The method may comprise any one or more features or steps relevant to or involving the use of any feature of any of the aforementioned mold stacks, molds, mold assemblies or molding systems.

For the avoidance of doubt, any of the features described herein apply equally to any aspect of the invention. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. For the avoidance of doubt, the terms“may”,“and/or”,“e.g”,“for example” and any similar term as used herein should be interpreted as non-limiting such that any feature so-described need not be present. Indeed, any combination of optional features is expressly envisaged without departing from the scope of the invention, whether or not these are expressly claimed. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:

FIG. 1 depicts a preform mold assembly according to an embodiment of the invention;

FIG. 2 depicts the preform mold assembly of FIG. 1 with the melt distributor omitted;

FIG. 3 depicts the core plate assembly of the preform mold assembly of FIGs 1 and 2 with one core omitted and another core assembly shown exploded;

FIG. 4 depicts an enlarged view of the region of FIG. 3 which includes the exploded core assembly;

FIG. 5 depicts a side view of part of the core plate assembly of FIGs. 3 and 4 illustrating the mounting of one of the cores to the core plate;

FIG. 6 depicts a section view through one of the core assemblies and an adjacent portion of the core plate to which the core assembly is secured;

FIG. 7 depicts a core cooling tube assembly of the core assembly of FIG. 6 shown from a first side;

FIG. 8 depicts the core cooling tube assembly of FIG. 7 shown from a second side;

FIG. 9 depicts an alternative, unitary core cooling tube assembly shown from a first side;

FIG. 10 depicts the core cooling tube assembly of FIG. 9 shown from a second side;

FIG. 11 depicts a section view along a central, axial plane through the core cooling tube assembly of FIGs. 9 and 10;

FIG. 12 depicts a further alternative, unitary core cooling tube assembly shown from a first side;

FIG. 13 depicts the core cooling tube assembly of FIG. 12 shown from a second side;

FIG. 14 depicts a section view along a central, axial plane through the core cooling tube assembly of FIGs. 12 and 13;

FIG. 15 depicts a yet further alternative, unitary core cooling tube assembly shown from a first side;

FIG. 16 depicts the core cooling tube assembly of FIG. 15 shown from a second side;

FIG. 17 depicts a section view along a central, axial plane through the core cooling tube assembly of FIGs. 15 and 16;

FIG. 18 depicts an alternative, two-part core insert for use in the preform mold assembly of FIGs. 1 and 2;

FIG. 19 depicts the two-part core insert of FIG. 18 in an exploded view;

FIG. 20 depicts a section view of a stack assembly incorporating the two-part core insert of FIGs. 18 and 19 along a central, axial plane;

FIG. 21 depicts the moving part of the preform mold assembly of FIGs. 1 and 2, including the core plate assembly and stripper plate assembly;

FIG. 22 depicts the stripper plate of the stripper plate assembly of the moving part shown in FIG. 21;

FIG. 23 depicts an exploded view of a pair of slides of the stripper plate assembly of FIG. 18;

FIG. 24 depicts three neck ring halves and their associated retaining assemblies that secure them to the slides;

FIG. 25 depicts an enlarged view of part of the stripper plate assembly of the moving half of FIG. 21 with the neck ring pairs omitted to expose the slides;

FIG. 26 depicts an enlarged view of FIG. 25 with the connecting bars omitted and illustrating the insertion of the guide shaft;

FIG. 27 depicts the cavity plate assembly of the preform mold assembly of FIGs. 1 and 2 with one of the cavity assemblies removed therefrom;

FIG. 28 depicts one of the cavity assemblies of the cavity plate assembly of FIG. 27;

FIG. 29 depicts the cavity insert of the cavity assembly of FIG. 28 with the gate insert omitted;

FIG. 30 illustrates the cooling channels in segment A-A of the cavity insert of FIG. 29;

FIG. 31 depicts the gate insert of the cavity assembly of FIG. 28;

FIG. 32 depicts one of the retaining pins of the cavity assembly of FIG. 28;

FIG. 33 depicts a partial section view of the cavity plate assembly through a column of cavity inserts of the cavity plate assembly of FIG. 27;

FIG. 34 depicts a partial section view of the cavity plate assembly through a row of cavity inserts of the cavity plate assembly of FIG. 27;

FIG. 35 depicts an enlarged view of the bypass and retaining pin region of the partial section view of FIG. 34;

FIG. 36 depicts a similar view to FIG. 35 illustrating an alternative bypass channel configuration;

FIG. 37 depicts a similar view to FIGs. 35 and 36 illustrating an alternative retaining pin configuration in which the bypass channel is described between the retaining pin and the cavity insert;

FIG. 38 depicts a partial section view of the gate region of an alternative cavity plate assembly in which a gate pad is provided between the nozzle tip and gate insert;

FIG. 39 depicts an exploded view of the gate pad and gate insert of FIG. 38;

FIG. 40 depicts a partial section view of the mold of FIG. 1 illustrating one mold stack, but with the melt distributor and core cooling tube assembly both omitted;

FIG. 41 depicts an enlarged view of area B of FIG. 39 illustrating the gap between the stripper plate and the core plate;

FIG. 42 depicts the cavity plate assembly of FIG. 27 being lowered onto the moving part illustrated in FIG. 21 during assembly; and

FIG. 43 depicts part of the alignment procedure for aligning the cores and neck rings relative to the cavities of the cavity plate assembly.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGs. 1 and 2, there is depicted a non-limiting embodiment of a preform mold assembly 100 according to the invention, which includes forty-eight cavities in this embodiment. The mold assembly 100 includes a first, moving part 110 for mounting to the moving platen (not shown) of an injection molding machine (not shown) and a second, stationary part 120 for mounting to the stationary platen (not shown) in the usual way. The first, moving part 110 includes a core plate assembly 200 and a stripper plate assembly 300. The second, stationary part 120 includes a cavity plate assembly 400 and a melt distributor 500, commonly referred to as a hot runner. In this embodiment, the melt distributor 500 is of a conventional type. This invention is particularly concerned with the product specific assembly 130 shown in FIG. 2, commonly referred to as the‘cold half 130. The cold half 130 includes the core plate assembly 200, stripper plate assembly 300 and cavity plate assembly 400.

As shown more clearly in FIGs. 3 and 4, the core plate assembly 200 includes a core plate 210, a pair of cam plates 220, four guide pins 230 and a plurality of core assemblies 240. The core plate 210 is substantially rectangular in plan with scalloped comers 211, for accommodating the debars (not shown) of an injection molding machine (not shown) within which the mold is mounted. The core plate 210 also includes four guide pin holes 212 through its thickness, which are horizontally inboard of each scalloped comer 211 and securely receive the guide pins 230. The core plate 210 also includes a plurality of ejector holes 213 through its thickness, for accommodating ejector pins (not shown).

A network of cooling channels 214a, 214b is included within the core plate 210, which feed into a plurality of cooling channel seats 215 in a front face CRF of the core plate 210 (as illustrated in FIG. 6). The cooling channel seats 215 are arranged in an array of six vertical columns and eight horizontal rows. Each seat 215 is surrounded by three core mounting holes 216, which extend through the thickness of the core plate 210 and are counterbored on a rear face CRR of the core plate 210. An

array of coupling bolts 217 are also inserted into holes in the core plate 210, which are also counterbored on the rear face CRR. One of the cam plates 220 is bolted to a central, lower region of the front face CRF of the core plate 210 and includes a pair of cam slots 221 on its upper surface. The other cam plate 220 is bolted to a central, upper region of the front face CRF of the core plate 210 and includes a similar pair of cam slots 221 on its lower surface. Both cam plates 220 have the same configuration, varying only in their orientation. The cam slots 221 of each cam plate 220 extend perpendicularly from the front face CRF and converge toward the free end of the cam plate 220.

CLAIMS

1. A cavity plate assembly (400, 3400) for a preform mold (100), the assembly (400, 3400) comprising a cavity plate (410) having one or more seats (412) and one or more cavity inserts (440) mounted to a front face (CVF) of the cavity plate (410) and in communication with a respective seat (412), wherein the or each cavity insert (440) comprises a molding surface (448) along its length at least two thirds of which extends beyond the cavity plate (410).

2. A cavity plate assembly (400, 3400) according to claim 1, wherein at least 90% of the molding surface (448) extends beyond the cavity plate (410).

3. A cavity plate assembly (400, 3400) according to claim 1 or claim 2, wherein the cavity plate (410) comprises a rear face (CVR) for mounting to a melt distributor (500), a depth (D) described from the front face (CVF) to the rear face (CVR) and a cooling channel (413 a) described therein which has a depth (Di) that is at least 15% of the plate depth (D).

4. A cavity plate assembly (400, 3400) for a preform mold (100), the assembly (400, 3400) comprising a cavity plate (410) having one or more seats (412) and one or more cavity inserts (440) mounted to a front face (CVF) of the cavity plate (410) and in communication with a respective seat (412), wherein the cavity plate (410) comprises a rear face (CVR) for mounting to a melt distributor (500), a depth (D) described from the front face (CVF) to the rear face (CVR) and a cooling channel (413a) described therein which has a depth (Di) that is at least 15% of the plate depth (D).

5. A cavity plate assembly (400, 3400) according to claim 3 or claim 4, wherein the cooling channel depth (Di) is at least 25% of the plate depth (D).

6. A cavity plate assembly (400, 3400) according to any preceding claim, wherein the or each cavity insert (440) comprises a body (441) with a mounting face (441a) and a spigot (443) projecting from the mounting face (441a) and received in a respective seat (412) of the cavity plate (410) such that the mounting face (441a) abuts the front face (CVF) of the cavity plate (410), the spigot (443) comprising a cooling channel inlet (445a) and a cooling channel outlet (445b) both of which are in fluid communication with cooling channel openings (413b, 413c) in the seat (412) of the cavity plate (410).

7. A cavity plate assembly (400, 3400) for a preform mold (100), the assembly (400, 3400) comprising a cavity plate (410) having one or more seats (412) and one or more cavity inserts

(440) mounted to a front face (CVF) of the cavity plate (410) and in communication with a respective seat (412), wherein the or each cavity insert (440) comprises a body (441) with a mounting face (441a) and a spigot (443) projecting from the mounting face (441a) and received in a respective seat (412) of the cavity plate (410) such that the mounting face (441a) abuts the front face (CVF) of the cavity plate (410), each spigot (443) comprising a cooling channel inlet

(445a) and a cooling channel outlet (445b) both of which are in fluid communication with respective cooling channel openings (413b, 413c) in the seat (412) of the cavity plate (410).

8. A cavity plate assembly (400, 3400) according to claim 6 or claim 7, wherein the cooling channel openings (413b, 413c) each have a depth (D2) that is at least 15% of the plate depth (D).

9. A cavity plate assembly (400, 3400) according to claim 8, wherein the depth (D2) of each cooling channel opening (413b, 413c) is at least 25% of the plate depth (D).

10. A cavity plate assembly (400, 3400) according to any one of claims 6 to 9, wherein the cavity plate (410) comprises a rear face (CVR) for mounting to a melt distributor (500) and a depth (D) described from the front face (CVF) to the rear face (CVR), the cooling channel openings (413b, 413c) being located at substantially the same depth.

11. A cavity plate assembly (400, 3400) according to claim 10, wherein the cooling channel openings (413b, 413c) in each seat (412) are on opposite sides thereof.

12. A cavity plate assembly (400, 3400) according to any one of claims 6 to 11, wherein the or each seat (412) comprises a first seat portion (412a) extending from the front face (CVF) and a second seat portion (412b) extending from the rear face (CVR), the spigot (443) of the cavity insert

(440) being received in the first seat portion (412a).

13. A cavity plate assembly (400, 3400) according to claim 12 comprising a gate insert (450, 3450) received within a seat (446) in the spigot (443, 3443) of each cavity insert (440), wherein the gate insert (450, 3450) extends into the second seat portion (412b, 3412b) and includes a recess (451a, 3456a) for receiving a gate pad (3457) or nozzle tip of a melt distributor (500).

14. A cavity plate assembly (400, 3400) according to claim 13, wherein the gate insert (450, 3450) comprises a cooling channel (454b) in fluid communication with the cooling channel inlet (445a) of the spigot (443, 3443) for receiving cooling fluid therefrom, the assembly (400, 3400) comprising a diverter (460) for diverting, in use, cooling fluid from the cooling channel (454b) of the gate insert (450) into one or more cooling channels (445) of the cavity insert (440).

15. A cavity plate assembly (400, 3400) according to claim 14, wherein the cooling channel (454b) of the gate insert (450, 3450) comprises a circumferential cooling groove (454) which cooperates with a facing surface of the spigot seat (446) and the diverter (460) comprises a pin (460) extending from the spigot (443, 3443) into the cooling groove (454).

16. A cavity plate assembly (400, 3400) according to claim 15, wherein the pin (460) comprises one of a pair of opposed pins (460) received within the cooling groove (454) to separate the cooling channel (454b) of the gate insert (450, 3450) into two segments, a first of the cooling channel segments providing a fluid connection between the cooling channel inlet (445a) of the spigot

(443, 3443) and one or more cooling channels (445) of the cavity insert (440), a second of the cooling channel segments providing a fluid connection between the cooling channels (445) of the cavity insert (440) and the cooling channel outlet (445b) of the spigot (443, 3443).

17. A cavity plate assembly (400, 3400) according to claim 16 comprising a bypass channel (455a) described between the pins (460) and the gate insert (450, 3450) which allows restricted flow from the first cooling channel segment directly to the second cooling channel segment.

18. A cavity plate assembly (400, 3400) according to claim 17, wherein the bypass channel (455a) is provided by a circumferential recess (455) in the circumferential cooling groove (454) of the gate insert (450, 3450).

19. A cavity plate assembly (400, 3400) according to claim 18, wherein the bypass channel (455a) is provided by a hole or cutaway in one or both of the pins (460).

20. A cavity plate assembly (400, 3400) according to any one of claims 15 to 19, wherein the or each pin (460) is threadedly engaged in a hole (449) through the spigot (443, 3443) of the cavity insert (440) and serves as a retaining pin (460) for retaining the gate insert (440) within the seat (446) of the spigot (443, 3443).

21. A cavity plate assembly (3400) according to any one of claims 13 to 19, wherein the recess comprises a gate pad recess (3456a) for receiving an outlet end (3457b) of a gate pad (3457) mounted to a melt distributor (3500).

22. A cavity plate assembly (400) according to any one of claims 13 to 19, wherein the recess (451a) comprises a nozzle tip seat for receiving a nozzle tip of a melt distributor (500).

23. A preform mold assembly comprising a melt distributor (3500) and a cavity plate assembly (3400) according to claim 21, wherein the melt distributor (3500) comprises one or more gate pad (3457) mounted thereto each having an outlet end (3457b) received in a corresponding gate pad recess (3456a) of the cavity plate assembly (3400).

24. A preform cavity insert (440) comprising a taper (447) at a first end, a molding surface (448) along its length, a mounting face (441a) at or adjacent a second end for mounting the cavity insert (440) to a cavity plate (410), wherein at least two thirds of the molding surface (448) is between the taper (447) and the mounting face (441a).

25. A preform cavity insert (440) according to claim 24, wherein at least 90% of the molding surface (448) is between the taper (447) and the mounting face (441a).

26. A preform cavity insert (440) according to claim 24 or claim 25 comprising a spigot (443) projecting from the mounting face (441a) for receipt within a seat (412) of a cavity plate (410), wherein the spigot (443) comprises a cooling channel inlet (445a) and a cooling channel outlet (445b) for fluid connection with a cooling channel (413a, 413b, 413c) in the cavity plate (410).

27. A preform cavity insert (440) comprising a molding surface (448) along its length, a body (441) with a mounting face (441a) at or adjacent one of its ends for mounting the cavity insert (440) to a cavity plate (410) and a spigot (443) projecting from the mounting face (441a) for receipt within a seat (412) of a cavity plate (410), wherein the spigot (443) comprises a cooling channel inlet (445a) and a cooling channel outlet (445b) for fluid connection with respective cooling channel openings (413b, 413c) in the seat (412) of the cavity plate (410).

28. A preform cavity insert (440) according to claim 26 or claim 27, wherein the cooling channel inlet (445a) is on a first side of the spigot (443) and the cooling channel outlet (445b) is on a second side thereof, opposite the first side.

29. A preform cavity insert (440) according to any one of claims 26 to 28 comprising one or more cooling channels (445) extending along and adjacent the molding surface (448).

30. A preform cavity insert (440) according to claim 29, wherein the one or more cooling channels

(445) comprise a plurality of axial channels (445c, 445e) which are connected together by one or more transverse channels (445d).

31. A preform cavity insert (440) according to claim 29 or claim 30, wherein the spigot (443, 3443) comprises a gate insert seat (446) for receiving a gate insert (450, 3450).

32. A preform cavity insert (440) according to claim 31 comprising a pair of threaded holes (449) through the spigot (443) for threadedly receiving retaining pins (460) extending into the gate insert seat (446), wherein the threaded holes (449) and the cooling channel inlet (445a) and outlet (445b) are spaced equally about the periphery of the spigot (443) such that the cooling channel inlet (445a) is on a first side of the spigot (443), the cooling channel outlet (445b) is on a second side thereof, opposite the first side and the threaded holes (449) are between the cooling channel inlet (445a) and outlet (445b) and extend orthogonally thereto.

33. A preform cavity assembly (430) comprising a preform cavity insert (440) according to claim

31 or claim 32 and a gate insert (450, 3450) received within the gate insert seat (446), wherein the gate insert (450, 3450) comprises a cooling channel (454b) in fluid communication with the cooling channel inlet (445a) of the spigot (443, 3443) for receiving cooling fluid therefrom, the assembly comprising a diverter (460) for diverting, in use, cooling fluid from the cooling channel (454b) of the gate insert (450, 3450) into the one or more cooling channels (445) of the cavity insert (440).

34. A preform cavity assembly (430) according to claim 33, wherein the cooling channel (454b) of the gate insert (450, 3450) comprises a circumferential cooling groove (454) which cooperates with a facing surface of the spigot seat (446) and the diverter (460) comprises a pin (460) extending from the spigot (443, 3443) into the cooling groove (454).

35. A preform cavity assembly (430) according to claim 34, wherein the pin (460) comprises one of a pair of opposed pins (460) received within the cooling groove (454) to separate the cooling channel (454b) of the gate insert (450, 3450) into two segments, a first of the cooling channel segments providing a fluid connection between the cooling channel inlet (445a) of the spigot (443, 3443) and one or more cooling channels (445) of the cavity insert (440), a second of the cooling channel segments providing a fluid connection between the cooling channels (445) of the cavity insert (440) and the cooling channel outlet (445b) of the spigot (443, 3443).

36. A preform cavity assembly (430) according to claim 35 comprising a bypass channel (455a) described between the pins (460) and the gate insert (450, 3450) which allows restricted flow from the first cooling channel segment directly to the second cooling channel segment.

37. A preform cavity assembly (430) according to claim 36, wherein the circumferential cooling groove (454) of the gate insert (450, 3450) comprises a primary groove (454) and the bypass channel (455a) is provided at least in part by a secondary groove (455) in the base of the primary groove (454).

38. A preform cavity assembly (430) according to claim 36 or claim 37, wherein the bypass channel (455a) is provided at least in part by a hole or cutaway in one or both of the pins (460).

39. A preform cavity assembly (430) according to any one of claims 34 to 38, wherein the or each pin (460) is threadedly engaged in a hole (449) through the spigot (443, 3443) of the cavity insert (440) and serves as a retaining pin (460) for retaining the cavity insert (440) within the seat (446) of the spigot (443, 3443).

40. A preform gate insert (450, 3450) comprising a cylindrical body (451, 452, 453; 3451, 3452, 3453) that describes:

a seat or recess (451a, 3456a) in a first end (451, 3451) of the cylindrical body (451,452, 453; 3451, 3452, 3453) for receiving a gate pad (3457) or nozzle tip;

a molding cavity portion (452a, 3452a) in a second end of the cylindrical body (451, 452, 453; 3451, 3452, 3453);

a gate (453a, 3453a) joining the seat or recess (451a, 3456a) to the molding cavity portion (452a, 3452a); and

a cooling groove (454) around the gate (453a, 3453a) and having a bypass groove (455, 3455) recessed therein;

wherein the cooling groove (454) describes a cooling channel (454b) within which is received, in use, a pair of diverters (460) that separate the channel (454b) into inlet and outlet channel segments and which describe, with the bypass groove (455, 3455), bypass channel segments (455a) that allow restricted flow between the inlet and outlet channel segment.

41. A preform gate insert (450, 3450) according to claim 40, wherein the cylindrical body (451, 452, 453; 3451, 3452, 3453) comprises a first diameter surrounding at least part of the seat or recess (451a, 3456a) and a second diameter surrounding at least part of the molding cavity portion (452a, 3452a), the second diameter being smaller than the first diameter and the cooling groove (454) being located at or adjacent the transition between the first diameter and the second diameter.

42. A preform gate insert (450, 3450) according to claim 41, wherein the first end (451, 3451) of the cylindrical body (451, 452, 453; 3451, 3452, 3453) comprises a third diameter larger than the first diameter with a shoulder (412c) described therebetween against which the spigot (443, 3443) of the cavity insert (440) abuts.

43. A preform gate insert (3450) according to any one of claims 40 to 42 in combination with a gate pad (3457), the gate pad (3457) comprising a substantially cylindrical hollow body describing a nozzle seat (3451a) and having a first, threaded end (3457a) and a second, outlet end (3457b) for receipt in the seat or recess (3456a) of the gate insert (3450).

44. A preform gate insert (3450) comprising a cylindrical body (3451, 3452, 3453) that describes: a seat or recess (3456a) in a first end (3451) of the cylindrical body (3451, 3452, 3453) for receiving a gate pad (3457) or nozzle tip;

a molding cavity portion (3452a) in a second end of the cylindrical body (3451, 3452, 3453); and

a gate (3453a) joining the seat or recess (3456a) to the molding cavity portion (3452a); wherein the seat or recess (3456a) in the first end (3451) is tapered at an included angle of between 20 and 50 degrees.

45. A gate pad (3457) comprising a substantially cylindrical hollow body describing a nozzle seat

(3451a) and having a first, threaded end (3457a) and a second, outlet end (3457b) for receipt in a seat or recess (3456a) of a gate insert (3450), wherein the second, outlet end (3457b) is tapered at an included angle of between 20 and 50 degrees.

46. A preform cavity plate (410, 3410) comprising a front face (CVF), a rear face (CVR) and an array of seats (412) with cooling channel openings (413b, 413c) therein, each seat (412, 3412) comprising a first seat portion (412a, 3412a) extending from the front face (CVF) and a second seat portion (412b, 3412b) extending from the rear face (CVR), the first seat portion (412a, 3412a) being larger than the second seat portion (412b, 3412b) with a shoulder or transition (412c, 3412c) described therebetween, wherein the front face (CVF) comprises a mounting interface adjacent each seat (412, 3412) to which a cavity insert (440) is mounted, in use, such that a spigot (443, 3443) thereof is received within the first seat portion(412a, 3412a).

47. A preform cavity plate (410) according to claim 46, wherein each cooling channel opening (413b, 413c) is at least 15% of the plate depth (D).

48. A preform cavity plate (410, 3410) comprising a cooling channel (413a) described therein, a front face (CVF) with an array of seats (412, 3412) in fluid communication with the cooling channel (413 a) for connection with respective cavity inserts (440), a rear face (CVR) for mounting to a melt distributor (500, 3500) and a depth (D) described from the front face (CVF) to the rear face (CVR), wherein the cooling channel (413a) has a depth (Di) that is at least 15% of the plate depth (D).

49. A cavity plate (410, 3410) according to claim 48, wherein the cooling channel depth (Di) is at least 25% of the plate depth (D).

50. A cavity plate (410, 3410) according to claim 48 or claim 49, wherein each seat (412, 3412) is fluidly connected to the cooling channel (413a) via a cooling channel inlet (413b) on a first side of the seat (412, 3412) and a cooling channel outlet (413c) at substantially the same depth as the cooling channel inlet (413b) and on a second side thereof, opposite the first side.

51. A preform cavity plate (410, 3410) comprising cooling channels (413a, 413b, 413c) described therein, a front face (CVF) with an array of seats (412, 3412) in fluid communication with the cooling channels (413a, 413b, 413c) for connection with respective cavity inserts (440), a rear face (CVR) for mounting to a melt distributor (500, 3500) and a depth (D) described from the front face (CVF) to the rear face (CVR), wherein each seat (412, 3412) comprises a pair of cooling channel openings (413b, 413c) fluidly connected to the cooling channels (413a, 413b, 413c) at substantially the same depth.