WO2012135678A2

WO2012135678A2 - Injection blow molding in a standard injection press with a rotating table

Info

Publication number: WO2012135678A2
Application number: PCT/US2012/031547
Authority: WO
Inventors: Dennis J. PRISCHAK; Cherian VARKEY; Douglas J. Prischak
Original assignee: Plastek Industries, Inc.
Priority date: 2011-03-31
Filing date: 2012-03-30
Publication date: 2012-10-04
Also published as: WO2012135678A3

Abstract

A molding apparatus has an injection section for injecting material for forming parisons. A blowing section is opposite the injection section for expanding parisons, the blowing section shiftable in a first direction toward and away from the injection section between a compressed/contracted condition of the molding apparatus and an expanded/extended condition of the molding apparatus. A transfer section between the injection section and the blowing section is rotatable by 180° about a second axis transverse to the first direction between a first condition and a second condition. The transfer section has a first side and a second side. Each side has a plurality of core members received in injection cavities and blow cavities during injection and blowing. In the first condition, the first side faces the injection section and the second side faces the blowing section. In the second condition, the first side faces the blowing section and the second side faces the injection section.

Description

INJECTION BLOW MOLDING IN A STANDARD INJECTION PRESS WITH A ROTATING

TABLE

CROSS-REFERENCE TO RELATED APPLICATION

[0001] Benefit is claimed of US Patent Application Ser. No. 61/469,982, filed March 31, 2011, and entitled "Injection Blow Molding in a Standard Injection Press with a Rotating Table", the disclosure of which is incorporated by reference herein in its entirety as if set forth at length.

BACKGROUND OF THE INVENTION

[0002] The invention relates to blow molding. More particularly, the invention relates to injection blow molding of bottles, jars, and the like.

[0003] In an exemplary blow molding process, a parison is initially molded in an injection molding system. The parison is a relatively thick-walled structure. The molded parison is transferred into a blow mold and air blown into the parison to expand/stretch the parison body (sidewall and base) to fill the blow mold cavity. In an exemplary molding process, the mouth of an exemplary bottle, jar, or other container is molded to final exterior form in the injection molding process. The body of the parison, however, remains smaller and relatively thick-walled compared with the ultimate container. The blow mold may closely engage the mouth of the parison allowing only the body to be expanded upon blowing. In other potential variations, there may be an expansion along the mouth area. US4358420 of Nielsen et al. discloses an injection blow molding system wherein injection and blowing sections and an ejection section are at 120° angles to each other. US7108501 of Araujo et al. discloses an injection-stretch-blow molding apparatus adapted from an injection molding press.

SUMMARY OF THE INVENTION

[0004] One aspect of the invention involves a molding apparatus having an injection section for injecting material for forming parisons. A blowing section is opposite the injection section for expanding parisons, the blowing section shiftable in a first direction toward and away from the injection section between a compressed/contracted condition of the molding apparatus and an expanded/extended condition of the molding apparatus. A transfer section between the injection section and the blowing section is rotatable by 180° about a second axis transverse to the first direction between a first condition and a second condition. The transfer section has a first side and a second side. In the first condition, the first side faces the injection section and the second side faces the blowing section. In the second condition, the first side faces the blowing section and the second side faces the injection section. Each of the first side of the transfer section and the second side of the transfer section includes a plurality of core members. The injection section has a plurality of injection cavities complementary to said plurality of core members. The blowing section has a plurality of blow cavities complementary to said plurality of core members.

[0005] The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a side view of an injection mold assembly in a contracted/compressed condition.

[0007] FIG. 2 is an injection end view of the mold assembly.

[0008] FIG. 3 is a blowing end view of the mold assembly.

[0009] FIG. 4 is a top view of the mold assembly.

[0010] FIG. 5 is an operator side view of a press containing the mold assembly in an expanded/extended condition.

[0011] FIG. 6 is a notional transverse sectional view of the mold assembly in a closed condition.

[0012] FIG. 6A is an enlarged view of an injection cavity area of the mold assembly of FIG. 6.

[0013] FIG. 7 is a notional vertical sectional view of the mold cavity in the closed condition.

[0014] FIG. 7A is an enlarged view of a blowing cavity region of the mold assembly of FIG. 7.

[0015] FIG. 7B is an enlarged view of an air assist bar actuator of the mold assembly of FIG. 7.

[0016] FIG. 8 is an isolated cutaway view of a mold cavity assembly. [0017] FIG. 9 is a view of the blow cavity of FIG. 7A upon core extension.

[0018] FIG. 10 is a view of the blow cavity of FIG. 9 upon blowing.

[0019] FIG. 11 is a view of the actuator of FIG. 7B in an actuated condition.

[0020] FIG. 12 is transverse notional view of the inboard face of a split cavity plate of an injection section of the mold assembly.

[0021] FIG. 13 is a view of a face of a stripper plate of a center/transfer section of the mold assembly.

[0022] FIG. 14 is a view of the inboard face of a split cavity plate of a blowing section of the mold assembly.

[0023] FIG. 15 is a notional transverse sectional view of the mold assembly during extension.

[0024] FIG. 16 is a side view of an interlock mechanism regulating extension.

[0025] FIG. 17 is a notional transverse sectional view of the mold assembly at full extension.

[0026] FIG. 18 is a stepped notional transverse sectional view of the mold assembly during center section rotation.

[0027] FIG. 19 is a stepped notional transverse sectional view of the mold assembly after rotation and during stripping.

[0028] Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

[0029] FIG. 1 shows a mold assembly 20. As is discussed further below, the exemplary mold assembly may be used in an otherwise conventional injection molding machine (press).

However, the present mold assembly is used to simultaneously mold parisons and blow articles (e.g., bottles or other containers) from already-molded parisons. The exemplary mold assembly is of generally rectangular planform, having a first side 22, a second side 24 (FIG. 2), a first end 26, and a second end 28. A top is shown as 30 and a bottom or underside is shown as 32. The first end includes an injection port 33 (FIG. 2) having a horizontal axis 500. In the exemplary assembly, a central transfer section (discussed below) is mounted for rotation about a vertical axis 502. Rotation may be actuated/driven by an actuator system 34 (e.g., a rotating table system with hydraulic or electric motor; FIG. 5 which also shows the mold assembly in an

expanded/extended condition). The port 33 may be in a locating ring 35. Opposite the locating ring 35, the second end has a locating ring 36. The locating ring 35 and locating ring 36 may register the stack in a press (FIG. 5, discussed below).

[0030] From the first end to the second end, the assembly comprises a stack of platens (plates) grouped in three exemplary sections: an injection parison section (half) 37, a central transfer section (alternatively center section and/or transfer section) 38, and a blowing (blow) section (half) 39 . As is discussed further below, the injection section and blowing section may be drawn toward and away from each other. When these sections are drawn away from each other, the center section may be rotated about said axis 502. The terms "inboard" and "outboard" respectively designate directions/locations toward the center of the machine and away from the center of the machine. The drawing of the sections and their components toward and away from each other defines a longitudinal direction which, in the exemplary embodiment, is parallel to the axis 500. Unless otherwise indicated, the reference to inboard/outboard is a longitudinal reference.

[0031] The exemplary injection section 37 comprises, of the platens/plates: a clamp plate

(top plate) 40 having an outboard surface 42, an inboard surface 44, and a peripheral surface or perimeter 46; a manifold plate 48 having an outboard surface 50, an inboard surface 52, and a perimeter 54; an injection plate (gate insert plate) 56 having an outboard surface 58, an inboard surface 60, and a perimeter 62; a split cavity plate (slide retainer plate) 64 having an outboard surface 66, an inboard surface 68, and a perimeter 70. In operation, the plates 40, 48, and 56 are rigidly fastened to each other to not move in normal use. As is discussed further below, the plate 64 is movably mounted to this assembly for controlled/limited longitudinal translation.

Reference to "top" and "bottom" reflect a traditional mold terminology although the exemplary system arrays the plates transversely rather than vertically.

[0032] The center/transfer section's plates (FIG. 1) comprise: a first stripper plate 72 (carrying a wear plate 73 (FIG. 6)) having an outboard surface 74, an inboard surface 76, and a perimeter 78; a first water/air plate (core retainer plate) 80 having an outboard surface 82, an inboard surface 84, and a perimeter 86; a first backup plate (center plate) 88 having an outboard surface 90, an inboard surface 92, and a perimeter surface 94; a second backup plate (center plate) 96 having an inboard surface 98, an outboard surface 100, and a perimeter surface 102; a second water/air plate 104 (core retainer plate) having an inboard surface 106, an outboard surface 108, and a perimeter 110; a second stripper plate 112 (also carrying a wear plate 113 (FIG. 6)) having an inboard surface 114, an outboard surface 116, and a perimeter 118 ending the center transfer section. The exemplary wear plates 73 are actually an array of wear plates each associated with a respective core and having an aperture through which the core passes. As is discussed further below, the plates 80, 88, 96, and 104 are rigidly secured/fastened to each other to not relatively move in normal operation. The stripper plates 72 and 112 are mounted for controlled/limited longitudinal translation relative to such assembly.

[0033] The blowing section 39 (FIG. 1) comprises: a split cavity plate (slide retainer plate) 120 having an inboard surface 122, an outboard surface 124, and a perimeter 126; a clamp plate (bottom plug plate) 128 having an inboard surface 130, a lower/outboard surface 132, and a perimeter surface 134; and a water (bubbler) plate (bottom plate) 136 having an inboard surface 138, an outboard surface 140, and a perimeter 142. As on the injection section, the plates 128 and 136 are secured/fastened to each other to not relatively move in normal operation. The plate 120 is mounted to this assembly for controlled/limited longitudinal movement.

[0034] In the exemplary horizontal arraying of the sections and their platens is relative to the factory floor/environment. Alternative implementations might vertically array such sections and their platens. [0035] FIG. 1 further shows a pair of plate interlock mechanisms 150 along the first side 22 (e.g., partially recessed along the platen perimeters). As is discussed further below, the interlock function to synchronize extension/longitudinal expansion of the sections relative to each other with a longitudinal expansion of the slide retainer plates 64, 120 relative to the remaining plates of their respective sections. In the exemplary embodiment along the first side 26, the upper interlock mechanism 150 couples the center section to the blowing section whereas the lower interlock mechanism 150 couples the center section to the injection section. On the opposite side, an upper interlock mechanism couples the center section to the injection section and a lower interlock mechanism couples the center section to the blowing section for symmetry and even force distribution. Upon on a 180° rotation of the center section, the relative positions are reversed. FIG. 1 also shows interlock bar assemblies 151 (e.g. along the sides and top/bottom (FIG. 4) )to key/register the split cavity plates of the injection and blowing sections to the adjacent stripper plates of the center section when the stack is in a compressed condition.

[0036] As is discussed further below, FIG. 1 further shows actuators 144 near the first side for shifting the stripper plates away from and back toward the remainder of the center section. In the exemplary embodiment, near the first side 22 the upper of two actuators is connected for extending the stripper plate 72 whereas the lower is connected for actuating the stripper plate 112. On the opposite side, these are reversed for force balancing. These exemplary hydraulic actuators may be accommodated in recesses spanning the associated plates. FIG. 4 furthers shows a central fluid inlet box 800 for admitting air and hydraulic fluid to the assembly. Along the top of the box 800, there are ports 802 for receiving hydraulic fluid and 804 for receiving air from controlled sources (not shown). These ports are coupled to associated fittings/ports on the side of the box.

[0037] Specifically, along the side of the box there are pairs of hydraulic connections 806 respectively associated with the two directions of actuators and pairs of air connections 808 for blowing parisons. The ports 806 may be connected via hoses (not shown) to ports/fittings 810 on the actuators 144 (FIG. 1). Thus, on each such actuator , one port may be controlled to deliver fluid to extend and the other may be controlled to deliver fluid to retract. Similarly, the ports 808 may be coupled to associated ports/fittings 812 along the center section platens (e.g. the platens 80 and 104 via hoses (not shown)).

[0038] FIG. 4 further shows electrical connectors for providing control and/or power to the mold stack. FIG. 2 also shows wiring 154 for delivering such power (e.g., to heating elements (not shown)) in the injection section. FIG. 2 also shows a transverse horizontal centerplane 504 and a longitudinal/vertical centerplane 506.

[0039] The stack may be contained within a receiving area/bay 160 (FIG. 5) of a press 162, having a first end plate 164, a second end plate 166 (at opposite ends of the bay), and an actuation mechanism (schematically shown by its housing) 168 for moving the first end plate and second end plate toward and away from each other in a direction parallel to axes 500 (discussed below). A plurality of tie rods 170 (e.g., two pairs) extend between the actuation mechanism 168 and the fixed end plate 164 and guide movement of the moving end plate 166. In the exemplary implementation, the first end plate is stationary as are the plates 40, 48, and 56 of the injection section. The actuation mechanism is responsible for shifting the remaining plates, to various degrees, longitudinally. The exemplary press is a conventional injection molding press.

Exemplary such presses are available from Sumitomo (SHI) Demag Plastics Machinery GmbH, Schwaig, Germany. An exemplary model is the DEMAG ERGOTECH 200-Series (e.g., 200-840H/200L). Such an injection molding press also includes an injection section 172 which provides a source of plastic material to be injected and includes the necessary screws or other devices for compressing and injecting the plastic material.

[0040] A further addition to the basic prior art injection molding press is a carriage 174 for supporting and guiding movement of the center section 38 and the actuator system 34 (e.g., a stepper motor and transmission). The exemplary carriage 174 includes end plates 176 and 178 respectively secured to the end plates 164 and 166. The exemplary carriage further includes a rack and pinion mechanism 180 linking the end plates 176, 178 and carrying the actuator 34 to maintain the actuator 34 and the mold center/transfer section 38 centered. Thus, with closure from the illustrated fully open condition, as the plates 166 and 178 move toward the plates 164 and 176, the actuator 34, center section 38, and axis 502 will move to the right at/by half the speed/amount. The opposite will occur upon opening. [0041] As noted above, the exemplary embodiment is configured to simultaneously mold a number (e.g., four) of parisons on the injection/parison side and blow the same number of previously-molded parisons on the blow side. The illustrated combination of the relatively small degree of blow and relatively small blow size and relatively small blow number represents a test configuration. An actual production configuration for similarly-sized blows and a similarly-sized press would be expected to involve a greater number (e.g., discussed below). FIG 6 is a

"notional" horizontal/transverse sectional view of the mold assembly. This and other views are notional to the extent of not necessarily representing a cut at a single plane They may show showing some features at, above, and/or below a plane and may use broken lines to highlight potential differences in elevation. Thus, features above or below a given plane may all be illustrated. FIG. 7 is, similarly, a notional vertical/longitudinal sectional view. For molding, the injection section has a corresponding number of injection cavities 200. Each of the cavities 200 is formed by a split cavity member mounted in the slide retainer plate 64. An exemplary split cavity member has two halves 202, 204 (FIG. 8). The exemplary cavity members 202 and 204 thus each surround 180 degrees of the cavity 200. For molding, each cavity 200 also contains a mandrel (core) 206. The cores 206 are mounted to the center section 38, each having a proximal end 208 and a distal end 210. An annular space surrounding the core forms the final cavity for molding the parison. The exemplary mold arrangement has four such cores on each side of the center section. The exemplary cores are arranged in two pairs in a rectangular array. In the exemplary implementation, the cavity halves 202 and 204 of one cavity are shared (e.g., part of the same piece or rigid assembly) with the corresponding halves of the cavity immediately above or below. As is discussed further below, in various sequences of operation, the cavity halves may open by internal movement away from the associated axes 510 of the associated core(s). FIG. 6 further shows an injection manifold 220 coupled to the associated injection port 33 and respective injection sprue (valve) assemblies 222 between the manifold and each cavity 200.

[0042] As is discussed further below, to guide opening and closing of the cavity halves 202,

204, each of these halves may have a plurality of associated guide pins 230. Each of the guide pins has a proximal end 232 secured in the manifold plate 48 or gate insert plate 56. A distal end portion 234 is within the slide retainer plate 64. The exemplary pins are accommodated within associated bores 236 of the associated cavity halves 202 or 204 (see also, FIG 8). FIG. 8 also shows three passageway legs vertically through each cavity half to pass a cooling fluid. These may be three separate legs, three parallel legs between plenums at ends of the mold half, or three legs of a single serpentine. If liquid coolant is used, supply and return hoses may pass freely through apertures in the peripheries (e.g., top and/or bottom) of the associated split cavity plate to connect with the passageways. Alternatively, air might be used as a coolant.

[0043] The exemplary pins have axes 512 at an angle (e.g., 15°-45°) off the associated core axis 510. As is discussed further below, this angling facilitates the opening of the cavities.

Specifically, a longitudinal separation of the slide retainer plate 64 from the gate insert plate 56 will cause the pins 230 to be drawn out of the bores 236. With the pins 230 fixed relative to the manifold plate and/or gate insert plate, the longitudinal movement forces the cavity halves laterally away relative to the axis 510 and disengages the cavity halves from the molded parison. Subsequent reverse movement of the slide retainer plate causes the cavity halves to contract to be ready to receive the next injection.

[0044] For registering of the split cavity plates, the exemplary configuration also shows a central heel block 240 for engaging the cavity halves 204 and lateral heel blocks 242 for engaging the cavity halves 202. Wedge blocks 244 are also shown. The heel blocks are mounted to the gate insert plate 56 and protrude into the slide retainer plate 64. They provide an angled low friction guide surface for guiding the cavity halves as the plates 54 and 56 move toward each other to the the closed/molding condition. The wedge blocks 244 are formed as inserts (e.g., steel) in the slide retainer plate 64 and cooperate with/locate the outboard surface of the outboard heel blocks to register the plates 56 and 64 and guide their rejoining movement. The wedge blocks 244 mate with the heel blocks 242 on mold closing and further support the heel blocks from deflection during injection.

[0045] The exemplary blow cavities 250 are split cavities similar to the molding cavities 200 but merely with larger cavity size. Accordingly, there may be split cavity halves 252 and 254 similarly cooperating with guide pins 256. Similar heel blocks 260 and 264 and wedge blocks 266 are also shown. [0046] In an initial condition, the plates are closed. The injection cavities 200 for molding the parisons are empty. At this point in first use, there are no already-molded parisons in the blowing section. At subsequent stages there will be already-molded parisons in the blowing section awaiting blowing.

[0047] In the injection section, plastic is injected from the press through the port 33 and manifold and into the individual cavities. The injected plastic passes through the valve assemblies 222 and initially encounters the core distal end 210 flowing toward the center/transfer section. The exemplary cavities are dimensioned and shaped to produce bottles or jars with threaded mouths. Accordingly, the cavity members 202 and 204 have threaded portions for molding the threaded mouth. Further details of the core construction are discussed in the context of blowing below.

[0048] While injection is taking place in the injection section, at first use, nothing will be occurring in the blowing section. In subsequent uses, blowing is occurring in the blowing section. For blowing, air is introduced through a port. The exemplary port is in the center section and may be connected to an external air supply (not shown) (e.g., house air) via a coupling (not shown). Air may pass from the port through passageways 292 in the associated core retainer plate 80/104 to the core. This allows air to inject through the mouth of the parison to fill the parison and expand the parison into the cavity 250.

[0049] When a given side of the center section rotates from the injection section to the blowing section, an actuation may occur to allow blowing of the parisons. This may be done via use of axially movable members on the center section to shift the cores or portions thereof.

Exemplary members are air assist bars 490 extending vertically across the center section (e.g., parallel to the length of the cavity members) so that one given air assist bar can interface with two exemplary mold cavities (or however many are associated with those cavity members).

[0050] FIG 7 A shows each core as being an assembly comprising a proximal member 450 mounted in the associated core retainer plate and having a central passageway/bore/channel 452.

The member 450 has a proximal end 454 and a distal end/rim 456. A distal end portion 458 of the proximal member 450 is dimensioned to form an interior portion of the parison 900 (and resulting blow 910 (FIG. 10)) along the mouth of such parison/blow. The core further comprises a distal member 460 having a distal portion 462 extending to the core distal end. The distal portion 462 is dimensioned to mold the remainder of the parison interior. The distal portion 462 has a proximal rim 464 forming a shoulder. The distal member 460 includes a rod/shaft 466 portion extending from the shoulder 464 into the channel 452 of the proximal member 450. The exemplary rod 466 may be a multi-piece assembly extending to a proximal end 470.

[0051] In an initial condition, the shoulder 464 abuts the rim 456. The distal member 460 may be shifted distally to open a gap 471 between the shoulder and the rim (FIG. 9). The distal end of the core may thus stretch the parison slightly longitudinally. The shift may be against the bias of a spring 472. With the distal member 460 extended, air may flow into the parison from the passageway 292. The air may initially flow into an annular plenum 476 in the periphery of the proximal member 450, and then through passageways 478 to the central passageway 452. From the central passageway 452 it may pass through axial grooves 480 in a shank portion of the rod 466 closely slidingly accommodated within the distal end portion 458 of the proximal member. From the grooves 480, the air may then pass into the gap 471 between the proximal member rim 456 and distal member shoulder 464. With the distal member 460 in its

retracted/closed condition, the gap is closed and airflow is blocked. The shift of the core distal member may be actuated by pressing on the end 470. This may be done via an air assist bar 490. In the exemplary implementation, each pair of cores has associated an air assist bar. The movement of the assist bar causes its outboard face to close a gap 491 with the adjacent face of the adjacent plate.

[0052] An actuation system 600 (FIG. 7B) is provided to actuate the extension of the core distal portions via the bars 490. The actuation system 600 comprises actuation components in the blow section which can cooperate with actuated and linkage components in the center section.

Accordingly, there are multiple sets of such components. The exemplary actuation system 600 comprises four such systems (two for each air assist bar at opposite ends thereof). Thus, each side of the center section includes four sets of the actuated and linkage components. The exemplary actuation system 600 is pneumatic with two ports 602 and 604. The ports 602 and 604 are coupled to a pneumatic cylinder 606 at opposite sides of the head 608 of a piston. A rod 610 depends from an underside of the head. The exemplary ports 602 and 604 are in the periphery/perimeter of the bottom plug plate and the cylinder 608 is within the bottom plug plate. A piston stop 612 may be mounted to the bottom plate and protrude into the cylinder (e.g., which is open to the adjacent face of the bottom plate but sealed thereto). The exemplary rod 610 passes through a bore 614 in the slide retainer plate to a tip/end 616. In an operational condition, the tip 616 may contact an adjacent end 618 of an actuator pin 620 which forms part of the linkage. The actuator pin passes through bores in the stripper plate and core retainer plate to a second end 622 in a compartment in the center plate. The end 622 engages an actuator lever (cam) 624 which is mounted to pivot about a transverse axis 540 (e.g., via a pin in the compartment). An actuated portion 640 of the lever 622, in turn, engages an inboard face of the air assist bar 490 near an outboard end of the air assist bar 490. The air assist bar may be spring biased inward by a spring 632 (e.g., of a spring and shoulder bolt assembly) with the bolt head in a compartment in the core retainer plate and the bolt shank passing through the air assist bar and threaded into the center plate at the base of a compartment in which the air assist bar is accommodated. FIG. 7B shows a retracted condition of the piston. FIG. 11 shows an extended condition with gap 491 closed and a gap 493 opened on the opposite face of the air bar 490. When the mold assembly has closed, the pistons are extended by introducing air into the ports 602 to pressurize the head spaces of the cylinders while allowing air to evacuate from the ports 604. This shifts the pistons and their rods 610 outwardly from the blowing section and presses the actuator pins 620 further into the center section, rotating the levers 624 and, in turn, shifting the bars 490 outwardly (optionally into contact with the underside of the adjacent core retainer plate) thus closing the gap 491 from the condition of FIGS. 7 A and 7B to the condition FIGS. 9-11. With the bars 490 on the blow side extended, air may be blown in to expand the parison of FIG. 9 into the blow 910 of FIG. 10. The pistons may then be retracted (e.g., via reversing coupling of the ports 602 and 604 to allow the bars 490 to retract).

[0053] After injection and blowing, the press begins to open. As is discussed further below, the opening of the press may both separate the sections 37, 38, 39 from each other and separate plates within the sections. In an initial stage of separation, the center section 38 is coupled (by the interlock mechanisms 150) to the adjacent plates 64, 120 of the other sections to transmit tensile force. This tensile force will cause the slide retainer plates 64 and 120 to pull away from their adjacent plates 56 and 128. As is discussed above, during this movement (as gaps 700 (FIG.

15) open) cooperation of the pins 230 with the bores 236 of the split cavities causes the cavities 200, 250 to open. The exemplary plates 64, 120 are thus mounted for a given amount of linear travel with a stop at a maximum gap opening (e.g., one inch in the exemplary embodiment). Upon reaching the limits of travel, force between the plates 64, 120 and the center section 38 will increase and the interlock mechanisms 150 coupling the center section to the plates may release (allowing gaps 702 (FIG. 17) to open up between the center section and the plates).

[0054] FIGS. 15 and 16 show further details of the interlock mechanism 150. The exemplary mechanism comprises two identical halves 710 on opposite sides of the transverse vertical centerplane 508. Each half 710 comprises a spring-loaded latch arm 720 and a first end portion 722 mounted to the main portion of the center/transverse section. In the exemplary embodiment, the proximal portion is founded in the associated platen 88 or 96 for relative rotation about an axis 530 (e.g., via a pin). A spring 724 (e.g., part of a plunger and coil spring arrangement) may bias the arm toward a latched/closed orientation/condition. Proximate a distal end portion 726, the arm 720 includes a latch hook or pawl 728 for engaging the adjacent platen 64 or 120 of the adjacent injection section or blowing section. The underside of the pawl 728 may engage a complimentary underside of a catch or other pawl-like structure 730. With these two surfaces engaged, tensile force may be transmitted between the center section and the platen 64 or 120 to keep all together. For releasing the latch, there is a release mechanism. An exemplary release mechanism 736 comprises a dowel pin 738 protruding transversely through the distal portion 726. The dowel pin cooperates with a ramping surface 740 of a trip bar 742. The trip bar 742 has a proximal portion 744 mounted to the associated platen 56 or 128. The ramping surface 724 is along a distal portion 746. During initial extension, as the gaps 700 begin to open, the pin moves along an intermittent portion of the trip bar approaching the ramp. With the pawl/catch surfaces engaged to each other, the platens 64 and 120 move away from the two platens of their sections to open the gaps. As the pin 738 encounters the ramp surface, the cooperation between the trip bar and the latch arm causes the latch arm to rotate against the spring bias and disengage the pawl/catch surfaces. This is synchronized so that the ramping will occur shortly before full extension occurs. Eventually, the pins pass over the ramping surfaces (a distal portion 760 thereof allowing the latch arms to rotate back to a neutral condition) with rotation being terminated by stop members 752. [0055] Thereafter, the gaps 702 may fully open so that the stack sections are in a fully opened condition (FIG. 17). With the stack fully opened, the actuator system 34 rotates (FIG. 18) the center section 180 degrees about the axis 502 (in an exemplary embodiment

counterclockwise as viewed from above). Successive moldings may involve alternating rotation (counterclockwise one time and then clockwise the next). This rotation brings the molded parisons from the injection section into alignment with the blow section (FIG. 5). It also brings the blown containers (blows) into alignment with the injection section. In the exemplary embodiment, it is at this point that the blows are ejected. They may alternatively be ejected before the rotation. However, the rotation allows extra time for cooling. They might alternatively be ejected during the rotation.

[0056] The exemplary ejection (or stripping) comprises axially shifting the associated stripper plate 72 or 112 away from its adjacent associated plate 80 or 104. In the exemplary embodiment, an array of guide pins 280 (FIGS. 6 & 12) guide movement of the stripper plates. The exemplary guide pins 280 serve two purposes. The exemplary guide pins have proximal ends 281 abutting each other along the center plane 508 of the center section and mounted in the associated backup plate. The guide pins extend through apertures in the associated core retainer plate and into a bushing 282 in the associated stripper plate. With the stripper plates retracted, the guide pins 280 protrude beyond the stripper plates. When the stack is fully compressed, the guide pins 280 are received in bores (e.g., of bushings 283) in the adjacent slide retainer plate 64/120. As the stack is closed, the pins 280 and, in the illustrated embodiment, distal portions of the bushings 283, may protrude into the split cavity plate bores to have sufficient length to maintain alignment of relatively thinner stripper plate. FIG. 12 also shows pins 286 used to align/register the slide plates with the adjacent manifold or other plate.

[0057] Actuation of the stripper plates may be via actuators (e.g., pneumatic or hydraulic).

Exemplary actuators 144 (FIG. 1) have cylinders in the center section center plates 88/96 and pistons protruding outboard thereof. To provide sufficient piston length, each exemplary cylinder extends through both backup plates thereby causing departure from mirror image symmetry of the two sides of the center section. As the actuators extend to shift the associated stripper plate(s) and open up the associated gap(s) in an extended condition (FIG. 19), the outboard face(s) of the stripper plate(s) push on the rims of the blows to shift/eject the blows off the associated cores whereupon the blows may fall. The ejected blows may be collected (e.g., in a hopper below the machine). After ejecting the blows, the actuators 144 may retract the associated stripper plate.

[0058] The press then contracts/compresses the sections and their plates (e.g., first retracting the stripper plate via its actuators 144 and then compressing the stack via the press's actuators). The compressing of the stack by the presses actuators (e.g., hydraulic, pneumatic, or

electromechanical) may operate in a reverse of the expansion with engagement between the center section and the injection and blowing sections during such compression returning the split cavity plates back to their original position (and thus driving (closing) the two halves of each injection cavity and blow cavity member back together). The injection/blowing cycle then repeats.

[0059] The mold assembly may be manufactured using materials and techniques typical for injection molding and blow molding equipment. Hardware will typically be combinations of aluminum alloys and stainless steel. Various routine manufacturing artifacts and features, components are not illustrated or not illustrated in detail. Such routine features include but are not limited to various fasteners, couplings, bearings, gears, fluid and vacuum lines and sources, and sensors, limit switches, input/output devices, control hardware. Exemplary parison/blow material may be polyethylene, polypropylene or other plastic or polymer. Although a relatively small degree of blow is illustrated, much larger degrees are possible as are more complicated shapes. The process steps may be programmed into the existing controller of the injection molding press into which the mold assembly is mounted. One or more processors of such controller may operate controlled components and receive sensor and control inputs based upon programs/instructions stored in memory and/or storage.

[0060] One or more embodiments of the present invention have been described.

Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, when applied to the modification of an existing system or for the manufacture of an existing product, details of the existing

system/product may influence details of any particular implementation. Accordingly, other embodiments are within the scope of the following claims.

Claims

CLAIMS What is claimed is:

1. A molding apparatus comprising:

an injection section (37) for injecting material for forming parisons (900);

a blowing section (39) opposite the injection section for expanding parisons, the blowing section shiftable in a first direction (500) toward and away from the injection section between a compressed/contracted condition of the molding apparatus and an expanded/extended condition of the molding apparatus; and

a transfer section (38) between the injection section and the blowing section rotatable by 180° about a second axis (502) transverse to the first direction between a first condition and a second condition, the transfer section having a first side and a second side, in the first condition, the first side facing the injection section and the second side facing the blowing section, in the second condition, the first side facing the blowing section and the second side facing the injection section,

wherein:

each of the first side of the transfer section and the second side of the transfer section includes a plurality of core members (206); and

the injection section has a plurality of injection cavities (200) complementary to said plurality of core members; and

the blowing section has a plurality of blow cavities (250) complementary to said plurality of core members..

2. The system of claim 1 wherein:

the transfer section first side and transfer section second side are sufficiently functionally equivalent to allow both said first side and second side to alternatively engage with the injection section for cooperating to mold the parisons and with the blowing section for cooperating to expand the parisons.

3. The system of claim 1 further comprising:

an actuation mechanism (168) coupled to the injection section and the blowing section to shift the blowing section relative to the injection section in the first direction.

4. The system of claim 1 further comprising:

a rotary actuator (34) coupled to the transfer section to drive said rotation about the second axis.

5. The system of claim 1 wherein:

each of the injection section, transfer section, and blowing section, comprise a plurality of platens.

6. The system of claim 5 wherein:

an interlock mechanism (150) couples the transfer section to the blowing section and the injection section so that a shift of the blowing section away from the injection section in said first direction causes the interlock mechanism to:

initially maintain engagement of adjacent said platens of the injection section and blowing section to said transfer section while expanding said adjacent platens relative to remaining platens of their respective sections; and then

release to allow disengagement of the transfer section from the injection section; and then blowing section as the shift progresses further toward the expanded/extended condition.

7. The system of claim 1 wherein:

the transfer section comprises a plurality of platens; and

the transfer section comprises at least one actuator (144) coupled to one or more of the platens of said transfer section to actuate relative movement of such platens.

8. The system of claim 1 wherein:

each of the core members comprises:

a proximal portion (450); and

a distal portion (462) axially shiftable relative to said proximal portion.

9. The system of claim 1 further comprising: means (600) for axially shifting said core members while inserted into the blow cavities to open gaps between the core members and the parisons prior to the expanding of the parisons.

10. The system of claim 9 wherein:

the means for axially shifting, shifts a distal portion (62) of the core members relative to a non-moving proximal portion (450).

11. The system of claim 10 wherein:

the distal portion molds an interior of a body portion of the parison and a distal portion (458) of the proximal portion (450) molds an interior of a mouth of the parison.

12. The system of claim 9 wherein:

the means comprises an actuator within the blowing section.

13. A method for operating the system of claim 1, the method comprising:

with the transfer section in the first condition, injecting material via the injection section to mold parisons and blowing via the blowing section to expand previously- formed parisons to form blows;

rotating the transfer section to bring the molded parisons into registry with the blowing section;

removing the blows;

engaging the injection section to the transfer section second side; and

engaging the blowing section to the transfer section first side.

14. The method of claim 13 wherein:

the removing is after the rotating.

15. The method of claim 13 wherein:

the transfer section further comprises:

a first stripper member along the transfer section first side;

a second stripper member along the transfer section second side; one or more first actuators coupled to the first stripper member for shifting the first stripper member; and

one or more second actuators coupled to the second stripper member for shifting the second stripper member,

wherein the removing the blows comprises, via the second stripper member actuators, shifting the second stripper member to eject the blows from the core members along the second side.

16. The method of claim 13 wherein:

after the injecting and blowing and before the rotating, the blowing section is shifted in the first direction away from the injection section.

17. The method of claim 16 wherein:

the shift also:

disengages the transfer section from both said injection section and said blowing section; and

to permit the disengagement:

opens injection cavities in the injection section; and opens blow cavities in the blowing section.

18. The method of claim 17 wherein:

the shift comprises applying tension in the first direction between the injection section and the blowing section, the tension:

initially being transmitted across the transfer section with the transfer section applying retention forces to an adjacent member of the injection section and an adjacent member of the blowing section to draw said adjacent members away from remaining members of the injection section and blowing section, respectively, in the first direction, the drawing driving the expansion of the injection cavities and the blow cavities; and upon a given shift of the adjacent members, there being increased resistance to further movement of the adjacent members away from the associated remaining members, the increased resistance overcoming engagement between the transfer section and the adjacent members allowing the transfer section to release the adjacent members and allowing the shift to continue to the expanded/extended condition of the molding apparatus.

19. The method of claim 18 wherein:

the engaging of the injection section to the transfer section second side and the engaging of the blowing section to the transfer section first side are part of a compression/contraction of the molding apparatus from the expanded/extended condition to the compressed/contracted condition.

20. The method of claim 13 further comprising:

with the transfer section in the second condition, injecting material via the injection section to form parisons and blowing via the blowing section to expand previously-formed parisons to form blows;

removing the blows;

engaging the injection section to the transfer section first side; and

engaging the blowing section to the transfer section second side.

21. The method of claim 20 wherein:

both said rotatings are in opposite directions about said second axis; and

the injectings, blowings, rotatings, removings, and engagings are cyclically repeated.

22. The method of claim 13 wherein there are:

in the first condition, the core members of the first side are receivable in injection cavities of the injection section and the members of the second side are receivable in blow cavities of the blowing section; and

in the second condition, the core members of the second side are receivable in injection cavities of the injection section and the core members of the first side are receivable in blow cavities of the blowing section.

23. The method of claim 22 wherein: prior to the blowing, the core members of the second side are shifted further into the parison to open an air gap through which the blowing enters an interior of the parison to expand the parison.