Field of the invention

[001] The present invention relates to a cold runner block for moulding articles.

Background of the invention

[002] An injection moulding apparatus can include a water cooled injector for injecting a moulding material, such as a silicone material, into a mould cavity. The moulding process can be interrupted or impeded when the injector becomes heated above the thermosetting temperature for the injected material. When this occurs disassembly of the injector is required to clean the nozzle or the injector.

[003] Any reference herein to known prior art does not, unless the contrary indication appears, constitute an admission that such prior art is commonly known by those skilled in the art to which the invention relates, at the priority date of this application.

Summary of the invention

[004] The present invention provides a cold runner block for use with one or more injector nozzles in an injection moulding system for dispensing a flowable material, including a block which has at least one injector nozzle mount that extends away from the block to receive at least one of the injector nozzles, an interior space of each mount defining an injection cavity that is adapted to receive an injection nozzle, the block having formed in it a coolant gallery that passes into the injection cavity.

[005] The injector nozzle can be seated against an inner wall of the injector mount by means of a sliding seal.

[006] A retained portion of the nozzle can be pushed against a seat for the nozzle, the seat extending inward from the inner wall of the injector mount, by a supply pressure of the flowable material.

[007] The block can be sealed by an end plate.

[008] The coolant flow path can have an inlet gallery and an outlet gallery that are located at different levels in the block with respect to the end plate.

[009] The block can have multiple mounts and multiple coolant flow paths, and a single plenum supplies all of the coolant cavities.

[010] Each injection cavity can be supplied from a same plenum for the flowable material.

[011] The nozzle can include a needle seat for stabilising a needle that extends through the injection cavity. [012] The coolant gallery can pass into the injection cavity via one or more passages through the mount and through the nozzle.

[013] The present invention also provides a cold runner block for use with one or more nozzles, the block extends into one or more injector mounts, an inner wall of each injector mount defining an injection cavity that is adapted to receive a nozzle, there being a radially inward extension that extends from the inner wall, wherein the nozzle is generally seated against the extension and is sealed against the inner wall by a sliding seal, so that an injection operation forces the nozzle against the extension.

[014] The nozzle can be axially compliant with respect to input ports of load dies.

[015] The sliding seal can be flexible and seal a gap between the nozzle and the inner wall, so that the nozzle can translate laterally within the injector mount by compressing the sliding seal.

[016] The block can have formed in it a coolant flow path that passes into the injection cavity.

[017] The block can be sealed by an end plate.

[018] The coolant flow path can have an inlet gallery and an outlet gallery that are located at different levels in the block with respect to the end plate.

[019] The block can include multiple nozzles that are each received in one of multiple injector mounts, and a single plenum supplies all of the injection cavities.

[020] The block can have multiple coolant flow paths, and a single plenum can supply all of the coolant flow paths.

[021] The present invention further provides a cold runner block for use with one or more injector nozzles, including a block which has formed into it one or more cavities in which the nozzles are seated, wherein a single plenum is adapted to supply a flowable material to all of the cavities.

[022] Each nozzle can be sealed against an inner wall of the cavity by a sliding seal.

[023] Each nozzle can translate axially with respect to the inner wall.

[024] Each nozzle can be spaced by a gap from the inner wall of the cavity, and the sliding seal can seal the gap.

[025] Each nozzle can translate laterally inside the inner wall by compressing the sliding seal.

[026] The block can have formed in it coolant flow paths which each pass into one of the cavities.

[027] The cavities are sealed by an end plate, and the coolant flow paths can have inlet galleries and outlet galleries that are located at different levels in the block with respect to the end plate. [028] Each coolant flow path can include an inlet passage that passes into the corresponding cavity, and an outlet passage that leads from the corresponding cavity, the inlet and outlet passages being straight passages built into the block.

[029] The block can have integrally formed in it injector mounts, the cavities being bound by the injector mounts.

[030] At least one cavity can include a longitudinal sleeve that is located inward of the nozzle.

[031] The sleeve can be spaced from the nozzle to accommodate the nozzle's inward longitudinal or axial translation.

[032] An outside diameter of the sleeve can closely match an inside diameter of the cavity.

[033] A needle associated with the nozzle can be of a substantially constant cross-section.

[034] The present invention also provides a cold runner blbck for use in an injection moulding system, the block having formed in it one or more injector mounts that extend away from a planar surface of the block, each injector mount further extends into and is integrally formed with a nozzle, wherein an inner wall and an outer wall of each injector mount and nozzle meet at a distal end of the nozzle to define a distal opening which can be blocked by a needle.

[035] Each inner wall can carry a needle guide which stabilises the needle.

[036] When the block is used with a mould die having one or more input ports, each input port can lined with a flexible material.

[037] The block can have formed in it one or more coolant galleries that each pass into an injection cavity bound by the inner wall.

[038] The present invention further provides a nozzle for an injection moulding system, the nozzle comprising one or more grooves formed into an outer surface of the nozzle, for receiving one or more seals, a portion of the nozzle having an inner wall and an outer wall, the inner and outer walls defining a nozzle coolant flow path.

[039] The one or more seals can each protrude outward of an outermost diameter of the one or more grooves.

[040] The nozzle can have a first portion and a second portion, the first portion having a larger outer diameter than the second portion.

[041] The inner and outer walls can be the inner and outer walls of the second portion.

[042] The outer wall can have formed through it a plurality of openings that each lead into the nozzle coolant flow path.

[043] The nozzle can further include a guide for stabilising a needle used in the injection moulding system. Brief description of the drawings

[044] An embodiment or embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[045] Figure 1 illustrates a partial cross section of a cold runner block, showing an injector mount which receives an injection nozzle;

[046] Figure 2 illustrates a cross section of a cold runner block having multiple injector mounts that each receives an injection nozzle;

[047] Figure 3 illustrates a cross section of the cold runner block, before assembly with a nozzle, shown in Figure 2;

[048] Figure 4 shows a cross section of an injection nozzle shown in the previous Figures;

[049] Figure 5 illustrates a plan view of the cold runner block, when viewed in the direction I shown in Figure 3;

[050] Figure 6 illustrates a plan view of the cold runner block when viewed in the direction II shown in Figure 3;

[051] Figure 7 illustrates a part sectional view through an injector mount and nozzle and respective die inlet;

[052] Figure 8 illustrates a cross section through a block utilising the arrangement of Figure 7;

[053] Figure 9 is a rear view of the block of Figure 8;

[054] Figure 10 is a simplified cross section through the block and rear plate of Figure 8;

[055] Figure 11 is a front view of the block of Figure 9; and

[056] Figure 12 illustrates a sectional view through an injector mount with integrally formed injector and a respective die inlet having compliance means thereon.

Detailed description of the embodiment or embodiments

[057] Figure 1 illustrates a partial cross section of a cold runner block 100 that can be used with an injection moulding system (not shown). The cold runner block 100 has an injector mount 10 which extends, generally perpendicularly from a generally planar surface 102 of the block 100. The injector mount 10 receives a nozzle 120 as will be described in more detail below. The injector mount 110 is integrally formed with the cold runner block 100, by any appropriate means such as direct material deposition, from materials such as stainless steel, titanium or a polymeric material, as in described in PCT/AU2008/001677 (WO 2009/062239), which is incorporated herein by reference.

[058] The injector mount 110 defines an injection cavity 2, into which a needle 130 and the nozzle 120 are received. The nozzle 120 is mounted so that the nozzle cavity 124 is in general alignment with the injection cavity 112. The needle 130 is located for axial alignment within the injection cavity 112. In operation the needle 130 moves relative to the nozzle 120, whereby it retracts to open the nozzle or extends to close the nozzle 20. When the nozzle 120 is closed the needle's tip 132 clears or blocks an exit zone 126 of the nozzle 120. In Figure 1, the needle 130 is shown to be in a closed position, and blocks off the exit zone 126 to prevent the injectable or flowable material from being dispensed out of the exit zone 126.

[059] A larger diameter portion 402 (see also figure 4) of the nozzle 20 is retained within the injector mount 110, whereas the smaller diameter portion 404 (also in figure 4) of the nozzle 120 extends out of the injector mount 110 through an opening located at the distal end 114 of the injector mount 110. The nozzle 120 is sealed against the inner wall of the injector mount 120 by means of two O-rings 128 and 129, which provide a sliding seal for the nozzle 120.

[060] The injector mount 110 has a radially inward extension forming a nozzle seat 116. The portion 402 of the nozzle 120 abuts against the nozzle seat 116. When the injection cavity 112 is filled with flowable product, the pressure from the product acts upon the surface area of the nozzle 120 and by virtue of the sliding seal from O-rings 128 & 129 in their respective grooves 08, the nozzle 120 is pushed towards the nozzle seat 116. The portion 402 of the nozzle 120 that is retained inwardly of the nozzle seat 116 can include one or more seal grooves 108 that receive the O-rings 128 and 129 to help seal the nozzle 20 against the inner wall of the injector mount 0. The seal grooves 108 can be located in any appropriate location to provide adequate sealing of the nozzle 120 to the inner wall 111 of the injector mount 110.

[061] The use of a sliding seal to mount the nozzle 120 onto the injector mount 110 helps reduce or eliminate the amount of machined parts. This produces a more streamlined flow path for the coolant.

[062] During the injection moulding process, due to the simplified connection between the nozzle 120 and the injector mount 110, temperatures can be better controlled. The overall structure is also simplified compared to prior art systems because the block 100 includes the integrally formed coolant galleries, and the connection from the coolant galleries to the corresponding nozzles 120 is also simplified.

[063] An advantage of the above is that, due to heat being efficiently removed from within the injection cavity 112, the flowable-material space in the injection cavity 112 can be smaller. That is, the diameter of the needle 130 can be larger, if desired, than one that is needed in a system with a less efficient heat removal system. Thus when the needle 130 needs to be replaced or removed, or when cleaning of the block must occur, there is less flowable material that can remain in the injection cavity 112. Accordingly the use of a larger needle reduces the size of the injection cavity, and results in a reduced amount of waste. [064] Further, because the simplified structure results in better heat extraction as described above, the system now has capacity for other optimization parameters, such as the flow rate at which the flowable material is supplied can be increased, thus allowing faster injection cycles.

[065] The cold runner block 100 has formed in it a coolant flow path. The coolant flow path includes a series of toroidal or part-toroidal shaped galleries (as seen in figure 6) which is formed below the inner wall 111 and outer wall 113 of the injector mount 110. The walls 111 and 113 are integrally formed with the rest of the block 100. The coolant flow path has fourteen passages 105 and 107 (as best seen in Figure 3) that generally surround the injection cavity 112 over the length of the injector mount 110, so that the flowable material in the injection cavity 112 can be prevented from setting by maintaining temperature control during an injection operation. The passages 107 feed coolant to the nozzle 120 via apertures 304 and the passages 105 take coolant from the nozzle 20 to deliver coolant to the outlet gallery 109. The nozzle 120 also includes a nozzle coolant pathway for cooling the flowable material inside the nozzle 120, similar to that as described in PCT/AU2008/001677 (WO 2009/062239).

[066] The inlet and outlet galleries 106 and 109 are located so that they are at different planar locations or at different levels to each other, relative to an end plate 101 that seals the injection cavity 12. The end plate 101 has one or more sealing grooves 103, for receiving sealing means such as O-rings, to ensure the injection cavity 112 is properly sealed when the needle 130 moves into and through the end plate 101.

[067] As shown in Figure 2 and 6, the cold runner block 100 has multiple injector mounts 110 located relatively close together, which is permissible due to the more efficient cooling system provided. The cold runner block 100 includes a plenum 202 for supplying the coolant to coolant galleries 106. The inlet plenum 202 is located a different level than the level at which the outlet plenum (see figure 6) is located which receives the heated coolant so as to exit the block 10. The heated coolant being that coolant which has been passed around the injection cavity 112 and nozzle 120 and hence has been warmed.

[068] Figure 3 shows the cross section through the cold runner block 100 depicted in Figures 2, 5, and 6. The inlet gallery 106 and outlet gallery 109 are more clearly shown with their associated passages 105 and 107. The passages 105 and 107 each terminate in an open port 304. The open ports 304 are adjacent to an O-ring seal grove 306 for receiving an O-ring 305, located at the distal end 114 of the injector mount 110. The ports 304 at the ends of the passages 105 and 107 provide communicable passage to the coolant flow path 122 in the nozzle 120. The inlet gallery 106 is fed by a lateral passage 602 (see Figure 6) which communicates with longitudinal or axial passage 505, each of which is sealed with respect to the plate 101 by O-rings in seal grooves 507.

[069] This arrangement of galleries and perpendicularly extending, straight running flow paths which are the passage 105 and 107, provides a relatively straight or uncomplicated flow path for the coolant, through the injector mount wall and the nozzle 120. The more streamlined flow path contributes to more efficient cooling as described above. Heated coolant exits the block through the outlet gallery 109 of the coolant flow path of the injector mounts to a heat exchanger to be cooled, and then the cooled coolant can be returned to the inlet plenum 202 which surrounds the base of the injector mounts 110. A single inlet plenum 202 can thus be used for supplying a relatively consistent cooling of multiple injector mounts 110.

[070] Figure 5 shows a view of the block 100 from direction I (marked in Figure 3), with the end plate 101 removed to illustrate the features of the block 100. Multiple injection cavities 112 are supplied by a single complex shaped and radially arranged plenum 502 for supplying the flowable material to be injected. A single sealing means such as a relatively large diameter O- ring seal to be located in a sealing groove 504 which is provided around the plenum 502, seals the plenum 502 with respect to the end plate 101.

[071] The plenum 502 which supplies the flowable material is preferably of a "spoke" or a series of radial arms, shaped so that the pressure at which the flowable material is supplied to the injection cavities 112 is substantially equalised or relatively consistent among the injection cavities 112. To ensure the plenum 502 is properly sealed to resist the pressures applied by the injection moulding system, the sealing means, namely O-ring in groove 504 has a pressure applied to it by, for instance, screws or fasteners (e.g. Unbrako® fasteners) in threaded holes 508, at a torque to provide a pressure to the O-ring that is appropriate for injection moulding systems (e.g. to seal the O-ring at around 300 bar).

[072] Figure 6 shows a view of the block 100 as viewed from direction II (marked in Figure 3.) The outlines of the eight injector mounts 110 are visible in this view. Also visible are the fourteen ports 304 of each of the injector mounts 110 that communicate with the respective nozzle coolant flow paths. The ports 304 and their passages 105 and 107 are generally equi- spaced around the periphery of the injector mounts 110.

[073] At a first level just below the base of the mounts 110, there is located the single plenum 202 for the inlet of coolant, which starts at the longitudinal or axial passages 505, which connect via lateral passages 602 to the inlet galleries 106, so that the coolant enters the inlet passages 107. The axial passages 505 are sealed by means of respective sealing grooves 507.

[074] Coolant then flows through the nozzles 120, enters the outlet passages 105 and then flows along the injector mount 110 to the outlet galleries 109, which then connect via its own lateral passages 604 to outlet longitudinal or axial passages 501. The longitudinal or axial passages 501 are sealed by O-ring seals located in seal grooves 503.

[075] The outlet passages 105, outlet galleries 109, outlet lateral passages 604, and outlet longitudinal passages 501 form an outlet plenum 203 which is the same size and shape as the inlet plenum 202. However in the view of Figure 6, the outlet plenum 203 is located beneath plenum 202, and only the outlet lateral passages 604 can be seen. [076] Figure 4 illustrates a cross section of the nozzle 120. The nozzle 120 includes the first larger diameter portion 402 which is retained inwardly of the nozzle seat 116 and a second smaller diameter portion 404 which passes out of the injector mount 110. The second portion 404 has an outer wall 406 and an inner wall 408. The outer and inner walls 406 and 408 meet each other at the tip 410 of the nozzle 120. The nozzle coolant flow path 122 is bound by these walls 406 and 408. The outer wall 406 includes a series of fourteen generally equispaced openings 412 that, when the nozzle 120 is mounted on the injector mount 110, align with the ports 304 of the passages 105 and 107.

[077] The nozzle 120 includes an internal needle guide 414 through which the needle 130 extends. The needle seat 414 snugly receives the needle 130, and helps stabilise the needle 130 with respect to the nozzle 120. The volume in the nozzle cavity 124 that delivers the flowable material is thus reduced by the needle 130 and the inner wall 408 of the nozzle 120. When the needle 130 is moved away the exit zone 126 to deliver the product to the die, the pressure in the nozzle cavity 124 causes the flowable material in the cavity 124 to be dispensed.

[078] The use of the sliding seals 128 and 129 on the nozzle 120 provides a compliance mechanism in this system. As there can be small dimensional imperfections in the manufacture of the mould dies, it is possible that the input ports to the die for the product are not aligned at the same planar level on the die. Further the injector mounts 110 themselves can include dimensional imperfections whereby they might be manufactured having different lengths. Because the nozzles 120 are slidingly sealed against the injector mounts 110, the pressure in the injection cavity pushes the nozzles 120 outward until they each meet their corresponding die inlet ports. By this means longitudinal or axial compliance is achieved.

[079] As the nozzles 120 can have a small longitudinal translation within the injector mounts 110, the openings 412 that lead into the nozzle coolant pathway 122 can be elongated in the nozzle's axial direction, so as to align with the ports 304 of the passages 105 and 107. This will ensure that, within the range of axial or longitudinal compliance needed, the ports 304 and the openings 412 into the nozzle coolant flow paths 122 can remain in register with each other.

[080] The arrangement illustrated in figure 1 can also provide lateral compliance, for example, to tolerate lateral misalignments between the injector mounts 110 and the die ports. The O- rings 128 and 129 can be sized so that they protrude out of the seal grooves 108, toward the injector mount wall. The diameter of portion 402 is smaller than the inside diameter of the injection cavity 112 with the O-rings 128 and 129 sealing the resulting gap. Also, the inner diameter of the seal groove 306 located adjacent to the nozzle seat 116 is larger than the outer diameter of the nozzle's smaller diameter portion 404. As a result there is also produced a gap around portion 404 of the nozzle 120. The O-ring 305 located in the groove 306 will be sized to protrude out of the groove 306 so that it seals this gap. By this arrangement, when there are lateral misalignments, the nozzles 120 can be moved laterally within the injector mount 110 until they align with the die ports, due to the compressing, or lessening of the compressive force on the protruded portion of the O-rings 128, 129, and 305. This lateral movement would result from the centring forces which tend to bring the nozzles 120 in register with the die ports.

[081] Illustrated in Figures 7 to 11 is a cold runner block 700 which is similar to the cold runner block 100 described above. As the block 700 is similar to the block 100 like parts have been like numbered.

[082] A difference between the cold runner block 100 and the cold runner block 700 of Figure 7, is that the needle 130 is of a relatively thin cross section when compared to the needle 130 of Figure 1. As this would result in a relatively large injection cavity 112, a longitudinal, cylindrical tubular sleeve (or "tube") 702 with an outside diameter very closely matched to the inside diameter of the injection cavity 112 is placed inside the injection cavity 112. The opposite ends of the tube 702 are sealed by O-rings placed in O-ring groove 704 and 706. By this mechanism, the effective size of the injection cavity 112 is substantially reduced.

[083] The length of the sleeve 702 is predetermined so as to provide a gap 708 between its end at 710 which is adjacent the sealing groove 706, whereby the space 708 allows the assembled system to provide sufficient axial compliance for the nozzle 120 (as described above).

[084] In Figure 7, it is also illustrated a cross section through part of a mould die 750 which has an inlet 752 shaped in a manner which matches the shape of the distal end of the nozzle.

[085] Illustrated in Figure 8 is a cross section through a block which embodies the arrangement illustrated in Figure 7. In Figure 8 as in Figure 2 the cross section is through 3 such injection mounts 110.

[086] The needle guide in the block 800 of Figure 12 whilst appearing to sit in the injection cavity 112 is integrally formed with the injection cavity 112 and the injector mount 110.

[087] The block 700 as illustrated in Figures 9, 10 and 11 is similarly informed to that illustrated in Figure 5 and 6. Apart from the reduced diameter aperture 711 through which the needle 130 passes the plate 701 , the only other major difference is that with the embodiment of Figures 5 and 6 a coextensive backing plate 101 was utilised whereas in the embodiment of Figures 7 to 11 the backing plate 701 of reduced size and an generally octagonal shape is utilised to provide the backing plate 701. This allows the axial passages 505 and 501 to receive a separate plate and or manifold system.

[088] Illustrated in Figure 12 is a block 800 which is similar to the block 700. As the block 800 is similar to the block 700 and 100 described above like parts have been like numbered. The difference between the block 800 and block 700 is that the injector mount 110 formed in this block 800 is of smaller diameter because the injector mount 110 has an integrally formed nozzle 120 at the end thereof. Such a system has significant advantages in that relatively few seals are required.

[089] Although this block 800 has no ability to provide axial or lateral compliance as the mount 110 and nozzle 120 are integrally formed,, compliance can be provided by the die 752 being constructed such that a flexible polymeric material 754 (such as polyurethane or similar material) can be positioned on to the shaped conical inlet 752 whereby when the nozzle 120 and die 750 are brought into contact with each other, any misalignment can be taken up by the polymeric pad 754. It is envisaged that the polymeric pad 754 will provide both lateral and axial or longitudinal compliance relative to the nozzle 120 on the block 800 of Figure 12.

[090] The embodiments or particular features shown in any of Figures 7 to 12, where appropriate, can be provided in the block 100 shown in Figures 1 to 6. For instance, the sleeve 702, albeit a smaller one, can be provide in the injection cavity 112 shown in Figure 1. Also, the same block can have different types of injection mounts. For instance, the same block can have both the kind of injection mount shown in Figure 1 , and the kind of injection mount shown in Figure 7, and also an injection mount that combines features from both types of aforementioned injection mounts.

[091] Where ever it is used, the word "comprising'' is to be understood in its "open" sense, that is, in the sense of "including", and thus not limited to its "closed" sense, that is the sense of "consisting only of. A corresponding meaning is to be attributed to the corresponding words "comprise", "comprised" and "comprises" where they appear.

[092] It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text. All of these different combinations constitute various alternative aspects of the invention.

[093] While particular embodiments of this invention have been described, it will be evident to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. The present embodiments and examples are therefore to be considered in all respects as illustrative and not restrictive, and all modifications which would be obvious to those skilled in the art are therefore intended to be embraced therein.