HK1131367B - Improvements in pet blow moulding machines - Google Patents

Description

Improved PET blow molding machine

Technical Field

The present invention relates to containers having integrally connected handles, preforms for bi-directionally blowing said containers and methods for their manufacture, and more particularly, to preforms and containers therefrom having integrally connected handles in at least two separate locations.

Background

Various attempts have been made to incorporate an integral handle into an injection blow molded container such as PET, see for example US4,629,598 to thompson and assigned to Tri-Tech systems international, Inc. Figure 1 shows a parison or preform for producing a bottle with a handle of US4,629,598. However, to date, various attempts to mass produce such structures have been unsuccessful. In contrast, what appears to be the best to do in commercial practice is a structure: the blown container receives the clip-on or card-on handle in a separate production step after it has been formed itself. See, for example, WO82/02371 and WO82/02370 to Thompson.

The injection stretch blow molding method is a process of: in which the parison is stretched axially and radially so that bi-directional orientation occurs.

The bi-directional orientation increases the tensile strength (peak load) of the container, reduces the permeability of the container by making the molecules more tightly aligned, and improves the drop impact resistance, clarity and reduces the weight of the container.

Not all thermoplastics may be oriented. The thermoplastics used are mainly polyethylene terephthalate (PET), Polyacrylonitrile (PAN), polyvinyl chloride (PVC) and polypropylene (PP). PET is by far the most used material, followed by PVC, PP and PAN.

Amorphous materials with a wide thermoplastic range (e.g. PET) are easier to stretch blow than partially crystalline types (e.g. PP). The approximate melting and stretching temperatures that yield the maximum container properties are:

material	Melting temperature (degree centigrade)	Drawing temperature (degree centigrade)
			PET	280	107
PVC	180	120
			PAN	210	120
PP	240	160

There are two main types of stretch blow processes: 1) a single stage process, wherein the preform and the blown bottle are made on the same machine; 2) a two stage process in which a preform is made on one machine and then blown on another machine.

The single stage process equipment is capable of processing PVC, PET and PP. Once the parison (extruded or injection molded) is formed, it is passed through a conditioning station where it is brought to the appropriate orientation temperature. The single stage process system allows the process from raw material to finished product to be completed on one machine, but the process is best suited for specific applications and small volume production due to the inability to easily change molds.

Oriented PVC containers are most commonly produced on extrusion type machines that employ a single stage process. The parison is extruded on a single-head or double-head unit. Temperature conditioning, drawing and thread forming are accomplished in various ways depending on the design of the machine. Many of the methods used today are patented.

Many oriented PET containers are produced on machines that employ a single stage process. The preforms are first injection molded, then conveyed to a temperature conditioning station, then to a blow molding station and stretch-blown into bottles, and finally to a demolding station.

For a two-stage process, the processing parameters for making preforms and blown bottles can be optimized. The operator does not need to compromise between preform design and weight, productivity, bottle quality, as he does on a plant employing a single-stage process. He can make or purchase preforms. If he chooses to make a preform, he can make the preform at one or more locations suitable for his market. Either high-throughput machines or low-throughput machines are available. Heretofore, two-stage extrusion type machines have generally been used to make oriented PP bottles. In a typical process, the preform is re-extruded, cooled, cut to length, reheated, stretched while trimming the finish, and demolded.

The object of the present invention is to produce a practical, easily implementable injection stretch blow moulded container made of orientable plastic preform material with a handle attached to the preform in an annular shape in at least two positions.

Disclosure of Invention

In a first aspect of the invention, there is provided a preform for the manufacture of a container, composed of orientable plastics material and arranged such that the resulting blown container comprises a support structure such as a handle; the preform comprises a shaped structure comprising a neck and an expandable portion below the neck, and at least one ring made of orientable plastic material integrally connected at least a first end to a respective first location on the preform, the ring constituting the handle when forming the container.

In another aspect of the invention, there is provided a method of forming a container having an integral handle, the method comprising:

(a) forming a preform comprising a neck and an expandable portion below the neck, the preform comprising at least one ring of orientable plastics material integrally connected at least a first end to a respective first location on the preform; and is

(b) The preform is subjected to a blow molding operation to expand the expandable portion to form a container body.

Preferably, the neck portion includes a locating ring located above the expandable portion.

Preferably, the container is formed from the preform in a two-stage process operation.

Preferably, said at least one ring made of orientable plastic material is integrally connected to said preform in said first position at said first end and in a second position at said second end.

Preferably, the handle allows at least two fingers of the adult hand to pass through.

Preferably, the ring is formed to have an I-shaped cross section at a portion of the shaft portion where the shaft portion protrudes from the outside of the tube.

In another aspect of the present invention, there is provided a parison or preform for an injection stretch blow molding process according to claim 1, the parison or preform being formed by an injection process comprising two separate injection points.

Preferably, the first injection point allows the injection of non-recyclable PET or similar plastic material.

Preferably, the second injection point allows the injection of PET or similar plastic material incorporating at least a portion of the recyclable material.

Preferably, said first injection point is intended to form a portion of the preform which is stretched when the preform is subjected to a stretch-blow moulding operation.

Preferably, the second injection point is used to form a portion of the preform that remains unexpanded or substantially unexpanded while the preform is subjected to a stretch blow molding operation.

In another aspect of the invention, there is provided a container manufactured by a two-stage injection stretch blow molding process, the container comprising a graspable handle integrally connected to the container in at least a first location so as to form an area between the handle and the container through which fingers of a human hand may pass.

Preferably, the first connection location comprises an integral connection between the handle and the container neck and is formed in a first stage of the two-stage process.

Preferably, the graspable handle is integrally connected to the container at the first connection location and the second connection location so as to form an enclosed area between the handle and the container through which the fingers of the human hand may pass.

Preferably, the second connection location is located at an expandable portion of the container.

Preferably, the second connecting position is located at the lower neck portion of the container at a substantially non-expanding portion.

Preferably, the first and second connection locations are located in a substantially non-expanded portion of the container.

Preferably, the container comprises an elongate substantially non-expanding neck to which said ring is secured.

Preferably, the preform further comprises a positioning ring, immediately below the positioning ring is a first unexpanded region, and below the first unexpanded region is a second unexpanded region.

Preferably, the first non-expanded region is formed to be slightly convex or otherwise distinct from the expandable portion of the preform.

Preferably, the second uninflated region is not distinct from the inflatable portion of the preform.

Preferably, the ring comprises a first rib integrally formed with the ring.

Preferably, the ring includes a second rib integrally formed with and extending from the second unexpanded region.

Preferably, the preform further comprises a rib connector integrally formed with and extending from the first unexpanded region, and the rib connector forms a continuous connection between the first rib and the second rib over the length of the ring.

Preferably, the second unexpanded region forms part of a temperature transition zone.

A preform as claimed in any of claims 20 to 26 wherein the first non-expanding region forms part of the temperature transition zone.

Preferably, the temperature transition zone is deformed during the stretch blow molding process.

Preferably, the preform is manufactured by a two-stage injection molding process, wherein the materials are injected into different locations in the mold, thereby forming a preform suitable for being composed of more than one material.

Preferably, in at least one stage of the two-stage process, an inner wall and an outer wall of the preform are formed, the inner wall being suitably made of a material different from that of the outer wall.

In another aspect of the invention, there is provided a container obtained from a preform according to any one of claims 20 to 30 by stretch blow moulding.

In another aspect of the invention, a two-step method of producing a PET container with an integral handle from a preform having a ring of orientable plastics material, at least one ring of orientable plastics material being integrally connected at least a first end to a respective first location on the preform is provided. The method comprises the following steps: shielding the ring of the preform during preheating of the preform prior to the stretch blow molding step.

Preferably, said at least one ring made of orientable plastic material is integrally connected to said preform in said first position at said at least first end portion and in a second position at said second end portion.

Preferably, the at least first end portion and the second end portion are substantially supported within the mold cavity during the stretch blow molding operation so as to be immovable.

In another aspect of the invention, there is provided a container constructed of biaxially orientable plastics material manufactured by a two stage injection stretch blow moulding process. The two-stage process includes a first stage in which a preform is manufactured and a second stage in which the preform is reheated and biaxially stretched to form the container. The container includes a graspable handle secured to the container in at least a first connection location, thereby forming an area between the handle and the container through which at least two fingers of a human hand can pass.

Preferably, the graspable handle is secured to the container in the at least first and second attachment locations so as to form an enclosed area between the handle and the container through which the fingers of the human hand can pass.

Preferably, said first connection location and said second connection location constitute an integral interconnection between the handle and the container and are formed at said first stage of said two-stage process.

Preferably, the container further comprises a locating ring at its neck.

Preferably, the container further comprises a first unexpanded region immediately below the locating ring.

Preferably, the container further comprises a second unexpanded region below the first unexpanded region.

Preferably, the first unexpanded region is formed to be slightly convex or otherwise distinguished from the portion of the container that is fully bi-directionally oriented in the second stage of the two-stage process.

Preferably, the second unexpanded region is not distinguished from the portion of the vessel that is fully bi-directionally oriented in the second stage of the two-stage process.

Preferably, in the second stage of the two-stage process, the second unexpanded region is slightly expanded.

Preferably, the handle includes a first rib integrally formed with and extending from the retaining ring.

Preferably, the handle comprises a second rib integrally formed with and extending from the second unexpanded region.

Preferably, the container further comprises a rib connector integrally formed with and extending from said first unexpanded region, the rib connector forming a continuous connection between said first rib and said second rib over the length of the handle.

Preferably, the second unexpanded region forms part of a temperature transition zone.

Preferably, the first non-expanding region forms part of a temperature transition zone.

Preferably, the temperature transition zone is deformed during the stretch blow molding process.

Preferably, the container is manufactured by said two-stage injection moulding process, wherein in said first stage of said two-stage process material is injected to different locations in forming said preform, whereby said container may be composed of more than one material.

Preferably, an inner wall and an outer wall of the preform are formed in the first stage of the two-stage process, the inner wall being made of a material different from that of the outer wall.

Preferably, the container further comprises discontinuous regions as defined in the description.

Preferably, the discontinuous region lies in a plane at an acute angle to the horizontal, the discontinuous region extending substantially over the entire periphery of the container.

Preferably, the position of the discontinuous region closest to the handle is located between the first and second ends of the handle.

In another aspect of the present invention there is provided a preform for manufacturing a container according to any one of claims 36 to 55 in a two-stage process, the preform comprising more than one wall profile.

Preferably, the preform has a first wall profile nearest to its neck and a second wall profile immediately below the first wall profile, the second wall profile being separated from the first wall profile by a first transition zone.

Preferably, the preform further comprises a third wall profile immediately below the second wall profile, the third wall profile being separated from the second wall profile by a second transition zone.

There is also provided an injection molding machine for producing a parison or preform according to claim 1, or any one of claims 7 to 11, or any one of claims 21 to 30 in a first stage of a two-stage process.

There is also provided a stretch blow moulding machine for manufacturing containers with an integral handle, the machine operating in accordance with the method of any one of claims 2 to 6 or any one of claims 34 and 35.

There is also provided an injection molding machine for making preforms with an integral handle, the injection molding machine comprising a mold having a channel that allows PET material to flow into a stem that constitutes a handle for a container blown from a preform produced by the injection molding machine.

Preferably, the channel of the mold comprises a return portion, whereby the stem is integrally connected to the preform at two locations.

In another aspect of the invention, a blow molding machine for blow molding containers having an integral handle is provided. The container is blow molded from a pre-injection molded preform. The preform includes a body portion and the integrally formed handle. The blow molding machine includes a preform loading station at which the preforms are oriented by a preform orienting device.

Preferably, the blow molding machine further comprises a preform loading station and a preform transfer system. The transfer system comprises a plurality of mandrels, each provided with a heat shield for at least partially covering the integrally formed handle.

Preferably, the preform orienting apparatus is adapted to align the integrally formed handle of the preform with the heat shield of the core rod and has structure to allow the handle to be inserted into the heat shield when the preform is engaged with the core rod.

Preferably, the blow moulding machine further comprises the following devices: the apparatus orients the integrally formed handle of the preform for entry of the preform into a stretch blow molding tool of the blow molding machine.

Preferably, the loading station comprises a feed track. Preforms are supplied to the feed track from a preform supply source. The output end of the feed track is arranged to output the individual preforms sequentially to the orienting apparatus.

Preferably, the body portion of the preform is provided to the orienting device in a state in which the axis of the body portion is substantially vertical.

Preferably, the orientation apparatus comprises a cylindrical sleeve fixed relative to the output end of the feed track. The sleeve has a substantially vertical axis. When the preform is output from the feed track, the axis of the sleeve is aligned with the axis of the body portion of the preform.

Preferably, said sleeve has an inner diameter adapted to allow said body portion of said preform to pass through said sleeve.

Preferably, the sleeve has a cut-out in its wall; the cutout being sufficiently wide to allow the integrally formed handle to pass therethrough; the cutout extends from a handle inlet at an upper end of the sleeve to a handle outlet at a lower end of the sleeve.

Preferably, the upper end of the sleeve is truncated so that at least a portion of the upper edge of the sleeve lies on a slope that is inclined relative to the axis of the sleeve.

Preferably, at least a portion of the upper edge of the sleeve is arranged to slope from at least one high point on the upper edge towards the handle entrance.

Preferably, the upper edge is divided into two inclined portions; each inclined portion forms an edge that is inclined from the at least one high point to respective first and second sides of the entrance of the cutout.

Preferably, the edges of each of the inclined portions intersect the respective first and second sides of the inlet with a smooth radius.

Preferably, said slope of said inclined portion is sufficient to ensure that said integrally formed handle of said preform slides downwardly along said inclined portion under the weight of said preform. The preform is rotated until the handle is aligned with the cut-out. The preform and the handle are then free to fall through the sleeve and the cut-out.

Preferably, an indexing table is provided below the orienting apparatus, the indexing table being provided with a plurality of sets evenly spaced around the periphery of the indexing table. Each of the sets is sequentially aligned with the axis of the sleeve at successive graduations of the indexing table.

Preferably, each said socket is arranged to receive and retain said preform dropped into the socket from said orienting apparatus when aligned with said axis of said sleeve. The handle maintains an orientation in the harness determined by the cut-out of the orientation apparatus.

Preferably, in a suitable subsequent indexing position of said indexing table, said preform is ejected upwardly from said sleeve. The preform is engaged with one of the plurality of core rods of the preform transfer system.

Preferably, each of said preforms is engaged with a core rod of said preform transfer system.

Preferably, each of the mandrels is provided with a handle protection shield. The shield partially surrounds the handle when the preform is engaged with the core rod.

Preferably, the mandrels are evenly spaced along the endless transport system. The transport system is driven in steps synchronously with the stepping of the indexing table.

Preferably, each of said mandrels of said preform transfer system is adapted to rotate about an axis of said preform. Each of the mandrels is in a predetermined orientation at the appropriate subsequent indexing position of the indexing table such that the handle protection shield is properly aligned to receive the integrally formed handle of the preform therein.

Preferably, the length of the preform transfer system and the rotation of the core rod are arranged to: the handle of each preform is in the predetermined orientation as the preforms are disengaged from the core rod.

Preferably, the mandrel and the preform handle are rotated to the predetermined orientation before the mandrel and preform enter the blow tool.

Preferably, the preforms are rotated during their transport past the row of preform heating elements by the preform transport system.

Preferably, the handle and the heat shield are placed in a cavity in the blow tool prepared for the handle and the preform.

Preferably, the handle and the heat shield are placed in separate cavities within the blow molding tool.

In another aspect of the present invention, an apparatus for orienting preforms for stretch blow molding containers is provided. The preform includes a generally cylindrical body with an integrally connected handle. The device comprises a sleeve with a cut-out and at least one sloping upper edge. The at least one ramped upper surface and the cutout are arranged to guide the integrally connected handle into alignment with the cutout.

Preferably, the preform is dropped into the sleeve, the bore of the sleeve being adapted to receive the body of the preform as a sliding fit. The underside of the handle is in sliding contact with the upper edge.

Preferably, the slope of said sloped upper edge is sufficient to cause rotation of said preform as said handle slides along said sloped upper edge, said rotation causing said integrally connected handle to align with said cut-out.

Preferably, the cut-out is adapted to allow the handle to slide therethrough when the handle and the cut-out are aligned.

In another aspect of the invention, a heat shield for protecting an integrally formed handle of a preform is provided. The heat shield protects the handle from excessive heat when the body portion of the preform is preheated prior to entering the stretch blow molding tool.

Preferably, the heat shield is attached to the core rod of the preform transfer system. The heat shield is adapted to at least partially surround the handle.

Preferably, the shield comprises side portions extending substantially on opposite sides of the handle. The side portions extending from opposite edges of a skeleton element attached to the mandrel; the skeleton element conforms to the shape of the upper portion of the handle.

Preferably, the edges of the side portions are shaped to selectively protect the interconnected locations of the handles from excessive heat. Portions of the side members are arranged to allow sufficient clearance to obtain sufficient heat penetration of the body region of the preform between the interconnection locations.

In another aspect of the present invention, an apparatus for controlling the orientation of a mandrel of a stretch blow molding machine is provided. The mandrel is adapted to support a preform comprising a body with an integrally attached handle. The apparatus is adapted to lock the mandrel in an oriented state or to release the mandrel into a freely rotating state.

Preferably, the mandrel is one of a plurality of mandrels of a preform transfer system of the blow molding machine.

Preferably, the integrally connected handle may be inserted into a heat shield connected to the mandrel when the mandrel is in the oriented state.

Preferably, when the mandrel is in the oriented state, the integrally connected handle is correctly oriented for entry into a blow tool of the blow molding machine.

Preferably, when the core rods are in the free rotation state, the core rods may be driven to rotate by a driving mechanism of the blow molding machine engaged with a rotation driving sprocket of the core rods during a preheating stage of the preform.

Preferably, the mandrel is provided with a spring loaded pawl. The spring loaded pawl is adapted to engage a notch located on a boss of the rotary drive sprocket. The spring-loaded pawls are activated or deactivated by a lever mechanism that contacts a fixed cam disposed at a predetermined position along the preform transport system.

Preferably, in a first of said predetermined positions, said lever mechanism is active to set said spring loaded pawl in a potential locked state. A rotational drive rotates the sprocket until the spring-loaded pawl engages the notch.

Preferably, in a second of said predetermined positions, said lever mechanism is operative to retract said spring loaded pawl to return said sprocket to said free-wheeling state.

In another aspect of the present invention, an apparatus for controlling the orientation of an integrally formed handle of a preform during a pre-heat stage of a stretch blow molding process is provided. The apparatus includes a mandrel provided with a shield to protect the handle from overheating during the pre-heating stage.

Preferably, the mandrel is one of a plurality of mandrels attached to a duplex conveying system. Each of the mandrels is rotatably mounted between the strands of the twin strand conveyor.

Preferably, the preform is inserted into the core rod at a preform loading station such that the handle is located in the shield.

Preferably, said transfer system extends between said preform loading station and said preform unloading station.

Preferably, each of said core rods is forced to rotate between said loading station and said unloading station. The rotation is caused by contact between a toothed pulley of the mandrel and a rack extending between the loading station and the unloading station.

Preferably, the mandrel completes an integer number of revolutions between the loading station and the unloading station such that the orientation of the protective cover at the unloading station is substantially the same as the orientation of the protective cover at the loading station.

Preferably, the orientation of the shield remains constant between the end of the rack before the unloading station and the start of the rack after the loading station. The orientation is maintained by a guide surface of the mandrel that is held in sliding contact with a fixed track.

In another aspect of the invention, a mandrel is provided for supporting and selectively thermally shielding a preform provided with an integral handle. The mandrel includes a vertically oriented socket portion and a shield portion depending from the socket portion.

Preferably, said socket portion is adapted to receive insertion of a neck portion of said preform and retain said neck portion. The shield is adapted to receive insertion of the integral handle and at least partially conceal the integral handle.

Preferably, the socket portion comprises a resilient plug. The stopper fits into the open neck of the preform when the inverted preform is forced upwardly into engagement with the core rod. The plug entering the open neck forms a friction fit sufficient to support the weight of the preform.

In another aspect of the invention, a method of controlling a preform for stretch blow molding a container with an integrally formed handle is provided. The preform includes a body portion and the integrally formed handle. The preform is transferred from a preform supply to a blow tool that blows the container. The method comprises the following steps:

a. passing said preform through a preform handle orientation device;

b. transferring the preforms to a preform transfer system;

c. transferring the preform from the transfer system to the blow molding tool.

Preferably, the method further comprises the steps of:

a. maintaining the orientation of the preform handle produced by the handle orientation device during the transfer to the preform transfer system and during the transfer to the blow tool;

b. rotating the preforms during their transfer along the transfer system past a row of preform heating elements;

c. shielding the integrally formed handle from excessive heating by the heating element.

Preferably, said preform handle orientation device comprises a cylindrical sleeve provided with a cut-out along the sleeve wall. The sleeve has an inner diameter that allows the body portion of the preform to pass through the sleeve. The width of the cutout allows the integrally formed handle to pass therethrough.

Preferably, the upper edge of the sleeve is inclined relative to the axis of the sleeve. The upper edge is inclined from at least one high point to the cut.

Preferably, the preform is fed to the orienting apparatus with the axis of the body portion and the axis of the sleeve substantially aligned.

Preferably, the slope of the upper edge ensures that the handle of the preform is slid down the ramp until the preform and the handle are rotated into alignment with the cut-out.

Preferably, the transfer of said preforms to said transfer system comprises the steps of:

a. receiving the preform passing through the sleeve of the orienting apparatus into a set of indexing tables;

b. holding the preform in the kit and maintaining the handle in the orientation produced by the orientation apparatus.

c. Ejecting the preform from the nest to engage the core rod of the transfer system.

Preferably, each core rod of the transfer system is provided with a preform handle protective shield. Each of the mandrels is rotated to a position where the protective shield and the preform handle are aligned when the preform is ejected from the set.

Preferably, the rotation of each mandrel is controlled to correctly adjust the orientation of the handle in order to bring the preform into the blow-moulding tool at the position of output from the transfer system.

In another aspect of the present invention, a method and apparatus for preheating preforms is provided. The preform comprising a body portion and an integrally connected handle, the method comprising the steps of:

a. orienting the preform to engage the preform with a core rod of a transfer system, the core rod having a shield substantially covering the handle;

b. arranging a row of heating elements in a form that allows the handle and shield to rotate;

c. setting the heating output of the individual heating elements to deliver a desired heat density profile to the body portion of the preform;

d. during a pre-heating stage, rotating the preforms as the conveyor system conveys the preforms past the array of heater elements.

Drawings

Embodiments of the invention are described by way of example below with reference to the accompanying drawings, in which:

FIG. 1 is a side view of a prior art parison;

FIG. 2 is a side view of a parison that includes features that may be used in embodiments of the present invention;

FIG. 3 is a partial side elevational view of a PET container blow molded from a preform that may be used in embodiments of the invention;

FIG. 4 illustrates the steps of forming a parison that may be used in another embodiment of the present invention;

fig. 5A is a side view of a preform according to another embodiment of the present invention;

FIG. 5B is a side view of a container formed from the preform of FIG. 5A;

FIG. 6 is a side view of a mold for making preforms in an open position;

FIG. 7 is a side view of the mold shown in FIG. 6 in a closed position;

FIG. 8 is a side view of the mold shown in FIGS. 6 and 7, showing the stem portion of the preform positioned therein;

FIG. 9 is a top plan view of a two-stage injection blow molding machine adapted to receive a preform and bi-directionally orient it to form a blown container in accordance with an embodiment of the present invention;

FIG. 10 is a cross-sectional side view of a mechanism for raising, lowering and rotating the handle cover for use with the blow molding machine of FIG. 9;

FIG. 11 is another cross-sectional side view of the mechanism of FIG. 10;

FIG. 12 is an enlarged cross-sectional side view of the blow molding machine of FIG. 9 showing the handle portion with the handle cover lowered to cover the preform;

13A and 13B show first and second cross-sectional side views of a preform suitable for loading in the blow molding machine of FIG. 9;

FIG. 14 is a perspective view of the preform shown in FIG. 13;

FIG. 15 is a perspective view of a container blown from the preform of FIG. 14 on the blow molding machine of FIG. 9;

FIG. 16 is a plan view of a mold half suitable for blowing a preform on the blow molding machine of FIG. 9;

FIG. 17 is a top view of the mold shown in FIG. 16 with the preform inserted in the mold ready to be blown on the blow molding machine shown in FIG. 9;

FIG. 18 is a bottom view of FIG. 17 with the mold halves positioned opposite each other;

FIG. 19 is another bottom plan view of FIG. 17, showing the preform in the position shown in FIG. 17;

FIG. 20 is a cross-sectional view of the mold half of FIG. 16;

FIG. 21 is a cross-sectional view of the mold shown in FIG. 16;

fig. 22 is a side view of the container of fig. 15 blown from the preform of fig. 13 and 14 in the mold of fig. 19;

FIG. 23 is a detailed cross-sectional side view of the neck and upper handle portion of the container shown in FIG. 22;

FIG. 24 is a side view of a preform including an enlarged first non-expanding region that may be used in embodiments of the present invention;

FIG. 25 is another side view of the preform of FIG. 24;

FIG. 26 is a side view of a container blown from the preform of FIG. 24 on the blow molding machine of FIG. 9;

FIG. 27 is a perspective view of the preform shown in FIG. 24;

FIG. 28 is a perspective view of the container shown in FIG. 26;

FIG. 29 is a side view of another alternative embodiment of a preform with an elongated or enlarged first uninflated region and adapted to be blown on the blow molding machine of FIG. 9;

FIG. 30 is a side view of the container from which the preform of FIG. 29 is blown on the blow molding machine of FIG. 9;

FIG. 31 is a plan view of a mold half for blowing the preform of FIG. 24;

FIG. 32 is a plan view of the mold halves of FIG. 31 with the preform of FIG. 24 inserted in the mold halves in preparation for blowing on the blow molding machine of FIG. 9;

FIG. 33 is a cross-sectional side view of the container blown in the mold shown in FIG. 32;

FIG. 34 is a detailed cross-sectional side view of the neck and upper handle portion of the container shown in FIG. 33;

FIG. 35 is a first perspective view of a container particularly suited for withstanding high internal pressures that may be used with embodiments of the present invention;

FIG. 36 is a second perspective view of the container shown in FIG. 35;

FIG. 37 is a first side elevational view of the container illustrated in FIG. 35;

FIG. 38 is a second side elevational view of the container illustrated in FIG. 35;

FIG. 39 is a plan view of the container shown in FIG. 35;

FIG. 40 is a side view of a preform that can be used to blow the container shown in FIG. 35;

FIG. 41 is a perspective view of the preform of FIG. 40;

FIG. 42 is a perspective view of a container with a strap attached handle according to an embodiment of the present invention;

FIG. 43 is a side view of a preform that can be used to blow the container shown in FIG. 42;

FIG. 44 is a cross-sectional side view of a preform with a composite integrally attached handle according to an embodiment of the present invention;

FIG. 45 is a cross-sectional side view of a container blown from the preform shown in FIG. 44;

FIG. 46 is a cross-sectional side view of an alternative embodiment of a container with a composite integrally connected handle;

FIG. 47 is a cross-sectional side view of a preform with a composite integrally attached handle according to another embodiment of the present invention;

FIG. 48 is a cross-sectional side view of a preform with a composite integrally attached handle according to another embodiment of the present invention;

FIG. 49 is a perspective view of the preform shown in FIG. 48;

FIG. 50 is a perspective view of a container blown from the preform of FIG. 48;

FIG. 51 is a top view of the container shown in FIG. 50;

FIG. 52 is a bottom view of the container shown in FIG. 50;

FIG. 53 is a side view of a preform used as a feedstock on a stretch blow molding machine according to an embodiment of the present invention;

FIG. 54 is a side view of a container produced from the feedstock shown in FIG. 1 on a stretch blow molding machine according to a first embodiment of the present invention;

FIG. 55 is a plan view of the stretch blow molding machine according to the first embodiment of the present invention;

fig. 56 is a side view of the preform of fig. 53 being loaded onto a transfer mandrel with a nested shield for transfer through the blow molding machine of fig. 55;

FIG. 57 is a side view of the assembly of FIG. 56 through the heating station of the blow molding machine of FIG. 3;

FIG. 58 is a side view of the assembly of FIG. 56 being aligned prior to entering the mold on the blow molding machine of FIG. 3;

FIG. 59 is a side view of the assembly of FIG. 56 in an initial position within the mold on the blow molding machine of FIG. 3;

FIG. 60 is a side view of the assembly of FIG. 56 in a blow position within the mold of FIG. 59;

FIG. 61 is a perspective view of a shield of the assembly shown in FIG. 56;

FIG. 62 is a perspective view of a 16-cavity preform mold adapted for injection molding a preform in the first stage of a modified two-stage process;

FIG. 63 is a perspective view of a preform produced by the mold of FIG. 62;

FIG. 64 is an end view of the mold shown in FIG. 62 in a substantially closed position;

FIG. 65 is an end view of the mold shown in FIG. 62 in a substantially open position;

FIG. 66 is a side view, partially broken away, of the mold shown in FIG. 62;

FIG. 67 is a partially removed end view of the mold shown in FIG. 62;

FIG. 68 is a partially removed end view of the mold shown in FIG. 62 in a substantially open condition;

FIG. 69 is an end view of the mold of FIG. 62 illustrating a preform injection operation;

fig. 70 illustrates details of the injector nozzle of the preform unit shown in fig. 62;

FIG. 71 illustrates the injector nozzle structure in a closed condition;

FIG. 72 is a schematic plan view of a two stage process stretch blow molding machine;

FIG. 73 is a perspective detail view of the preform handle orienting device;

fig. 74 is a perspective view of an indexing table for transferring the oriented preforms to the core rods of the pre-heat stage transfer system;

fig. 75 is a cross-sectional view of the oriented preform coupled to the core rod of the pre-heat stage transfer system with the preform handle positioned within the heat shield;

FIG. 76 is an enlarged side sectional view of the preform and heat shield configuration shown in FIG. 75;

fig. 77 is a preferred arrangement of an array of heater elements arranged for preheating preforms in accordance with the present invention.

Detailed Description

Two-stage workingFirst preferred embodiment of the Process

Fig. 1 shows a prior art preform or parison as described at the outset.

Fig. 2-41 illustrate preforms and resulting containers, and methods and manufacturing machinery therefor, which are adapted to include composite integrally connected handle stems or rings, in accordance with embodiments of the present invention.

In this specification, the term "integral connection" or "integrally connected" means that the connection between the handle and the preform (and the corresponding connection subsequently on the container blown from the preform) is made of the same material as the handle and preform material and is formed at the same time as the preform as an intrinsic part of the preform.

All of the first embodiments of the present invention are made in a two-stage process.

In a particular form, the embodiments are made in a modified two-stage process, as described below.

The two-stage process is the least costly method of manufacturing oriented PET containers. The two-stage process of injection molding preforms and then transporting the preforms to the blow molding location allows companies to become preform manufacturers and sell preforms to blow molding manufacturers. Thus, for companies wishing to enter the targeted PET container market, their capital requirements can be minimized. The two-stage stretch blow molding process can also be used to produce oriented PVC containers. Preform design and its relationship to the final container are always the most important factors. Suitable stretch ratios in the axial and circumferential directions are important if the container is to be properly packaged for its intended product. Examples of draw ratios are as follows:

material	Draw ratio	Directional temperature (Fahrenheit)Degree number)
			PET	16/1	195-240
PVC	7/1	210-240
			PAN	9/1	220-260
PP	6/1	260-280

Fig. 3 shows a container 10 that may be used in embodiments of the present invention, which includes a neck portion 11 and an expansion portion 12.

Neck 11 has a threaded portion 13 and a retaining ring 14, with retaining ring 14 being integrally formed with a stem portion 15. A first portion 15a of the stem 15 extends outwardly from the positioning ring 14 and a second portion 15b of the stem 15 is inclined relative to the first portion 15a so as to be approximately parallel to the vertical axis of the container 10. In this example, the first portion 15a is at an angle slightly greater than 45 ° to the bottle wall 20 and the second portion is at an angle of about 20 ° to the bottle wall 20.

The particular shape of the stem portion 15 is selected so that it can be grasped by the fingers of a human hand when the stem portion forms a handle.

The stem 15 terminates in a stem end 16 that is generally downwardly directed generally toward the closed end of the container 10.

In this example, the cross-section of the stem 15 is I-shaped to prevent adverse effects at or near the point of attachment 17 of the stem 15 to the retaining ring 14 after the preform 10 is blown.

These adverse effects include, in particular, stress effects and air inclusions caused by non-uniform cooling over the preform volume of different cross-sections.

In this example, the preforms were made of PET and were prepared using a heated mold.

To produce the container 10, a parison or preform 26 (see fig. 2) according to an embodiment of the present invention may be placed in a blow molding machine (not shown) and blow molded according to the bi-directional blow molding technique while the neck 11 is held in the mold so as not to expand. Initially, the expandable portion of the preform below the neck may be mechanically pulled down to the bottom of the mold, and then a closed region 19 may be formed between the bottle wall 20 and the stem 15 of the container 10 during blow molding of the container 10 by blowing the body of the preform outwardly with compressed air so that the support portion 18 is formed around the stem end 16.

In a particular form, enclosed region 19 has a sufficient cross-sectional area to allow at least two fingers of a human hand to be inserted therein and grasp handle 15 to support container 10.

The blow molding operation is performed as follows: the bottle or container has optimal strength by achieving bi-directional orientation of the molecules of the preferred PET material and improved barrier properties to reduce oxidation.

According to an embodiment of the present invention, the neck 11 and the handle 15 may be crystallized by overheating the respective portions of the preform. The crystallization of the handle increases its stiffness, which aids in the orientation of the preform and allows less material to be used.

Crystallization of the neck and handle may be achieved by applying hot oil, applying open fire or blowing hot air over the neck and handle.

The position of the handle 15 on the positioning ring 14 ensures a minimum interference with the blow-moulding process applied to the remainder of the preform. Either single stage or dual stage processes can be used.

Detailed description of other embodiments

Figure 1 shows a prior art preform or parison 21 of US4,629,598. The concept disclosed in this prior art is to form the handle 23 from a retaining ring of the unexpanded portion 22 of the parison 21.

With reference to fig. 2 and with reference to the detailed description of the preferred embodiment, the structure of fig. 1 is improved in many respects according to the present invention.

Inserts 2A, 2B and 2C show a bulbous portion 27 forming part of shaft end 16, which is shaped as a downwardly extending hook 24a, a ball 24B and an upwardly extending hook 24C, respectively.

These portions are shaped to mechanically engage with the blown portion of the container 10 that is adapted to encase the bulb 27.

The process of effecting the second stage blowing of the expandable portion 12 of the parison 26 to encase the bulb portion 27 of the rod end 16 is a bi-directional orientation process of stretch blowing.

Referring to fig. 4, a particular method of making a preform or parison is shown. The method includes a two-stage process for forming a parison by an injection molding process. In the first stage, the first injection mould inlet 28 allows the entry of the plastic material used to form the expandable portion 12 of the parison 26 (expanded in the blow-moulding stage of forming the container, with reference to figure 3).

In a second stage of the injection molding process to form the parison 26, the second injection mold inlet 29 admits plastic material for forming the unexpanded portion 25 of the parison 26.

The two-stage injection scheme allows for the injection of different plastic materials through the first injection mold inlet 28 and the second injection mold inlet 29.

In one particular form, the plastic material injected through first injection mold inlet 28 is a non-recyclable or substantially non-recyclable plastic material, while the plastic material injected through second injection mold inlet 29 is a recyclable or at least partially recyclable plastic material.

This solution allows to control the ratio of use of recyclable and non-recyclable plastic materials, so as to achieve an optimal economy in the manufacturing process of the parison 26.

In a variant of this solution, the second stage step consists in making two layers of bottle wall comprising an inner wall 51 and an outer wall 52 in the unexpanded section 25. The inner wall 51 is made of a clear or uncontaminated PET material and acts as a barrier to the outer wall 52. The outer wall 52 may be manufactured from recycled material 52. Such a double-walled solution can be produced by using a sliding core structure, which is a variation of the mold structure and process described later in this specification with reference to fig. 6, 7 and 8.

Of course, the steps of the first and second stages in fig. 4 may be interchanged in order.

A parison and a container made therefrom according to another version are shown in fig. 5A and 5B, respectively. The same reference numerals are used for the same components as in the previous embodiment.

In this version, the parison 21 includes a locating ring 14, immediately below the locating ring 14 are a first uninflated region 30 and a second uninflated region 31. The first uninflated region 30 may itself be formed to be slightly raised or otherwise distinguished from the inflatable portion of the parison 21. The second uninflated region 31 may not be distinguishable from the inflatable portion of the parison 21, but in use the blowing operation should ensure that the second uninflated region 31 does not inflate during the blowing process.

In this case, the stem portion 15 includes a first rib 32 extending from the retaining ring 14 and integrally formed with the retaining ring 14. The stem 15 further comprises a second rib 33 extending from the second unexpanded region 31 and integrally formed with the second unexpanded region 31. The stem 15 further comprises a rib connector 34 extending from the first unexpanded region 30 and integrally formed with the first unexpanded region 30, the rib connector 34 forming a continuous connection between the first rib 32 and the second rib 33 over the length of the stem 15.

The parison 36 of fig. 5A is then blown in the manner previously described to form the volume 35 of the container 37 shown in fig. 5B. The neck, including the stem 15, the positioning ring 14, the first uninflated region 30 and the second uninflated region 31, remains uninflated while the expandable portion 36 of the parison 36 is stretched bi-directionally to form the primary volume 35 of the container 37. The stem end 16 may comprise a bulbous portion for connection to the container 37 according to the previous embodiments, or alternatively or additionally may comprise an applied adhesive material, whereby a chemical bond is formed between the stem end 16 and the wall of the container 37 through the use of a chemical blank.

In a variation of the arrangement shown in fig. 5A and 5B, the first and second unexpanded regions 30, 31 can form part of a single unexpanded region.

In another variant, the second non-expanded zone 31 may be arranged in the temperature transition zone of the container and a smaller expansion may occur during the blow-moulding step.

In another variation, both the first 30 and second 31 unexpanded regions may be disposed in the temperature transition zone immediately below the positioning ring 14, and these regions may experience less expansion during the blowing process.

The latter two variants described above have the following advantages, namely: it has been observed that expansion in the temperature transition zone can be limited by appropriate mold design and process control, thereby controlling the adverse deformation effects caused by the rigid interconnection of the temperature transition zones 30, 31 with the retaining ring 14 (or other non-expanding portion of the neck 11) via the second ribs 33 and rib connectors 34.

In use, preforms and containers blown from preforms can be made as follows:

in the injection molding process, the preform is formed from an orientable plastic material, preferably PET or the like. The slidable mold, as shown in fig. 6, 7 and 8, includes a slide core 40, a slide block 41, a main body 42, a base 43, a push block 44 and a spring holder 45. Fig. 6 shows the die in an open position, fig. 7 shows the die in a closed position, and fig. 8 shows a side view of the receiving rod.

The preforms completed in the second and preferably separate step are then transferred to the stretch blow molding machine and are first reheated to a suitable transition temperature on the stretch blow molding machine (see the opening part). The unexpanded region of the preform, including the positioning ring 14, and the stem portion 15 are substantially shielded from the reheating process by suitable protection means. In most instances, there may be temperature transition zones in both of the regions 30, 31 described with reference to fig. 5A, 5B.

The reheated preform is then placed in a mold and biaxially stretched to blow the expandable region to its maximum size using procedures known in the art. During this process, the preform may be supported on the neck portion 14 and may also be supported on the stem portion 15. The stem 15 does not participate in the blowing process, but its stem end 16 may be surrounded by an outer wall portion of the blown container.

Detailed description of a method of manufacture incorporating an improved two-stage stretch blow molding machine

Fig. 9 shows a modified two-stage stretch blow molding machine 110 suitable for stretch blow molding (including bi-directional orientation) preforms of the foregoing embodiments and preforms of other embodiments described below with reference to later figures. As mentioned above, these preforms may be previously injection molded at a location remote from the current blow molding machine.

The blow molding machine 110 includes a first carousel 111, the first carousel 111 being adapted to receive preforms 112 with integral handles from a chute 113 into holes 114 arranged around the periphery thereof.

As the first carousel 111 rotates, the preforms 112 move from the chute 113 through the apertures 114 to a second carousel loading position, where the preforms 112 are transferred onto mandrels 115 mounted near the outer periphery of a second carousel 116.

A portion of the second carousel 116 of about 270 ° is arranged as a preheating tunnel 117, where the preforms 112 are progressively heated by heating means installed opposite the path of travel of the preforms.

The preforms 112, suitably preheated, are loaded in turn in the holes 119 of the third carousel 120. The third carousel acts as a transfer mechanism for properly orienting the preforms 112 about their longitudinal axes and placing the preforms 112 into the mold cavities 121, including the first mold half 122 and the second mold half 123.

It must be noted that during the time it takes to be in the preheating tunnel 117, the preform 112 is rotated about its longitudinal axis by the core rod and the handle guard 124 is mounted over the stem of the preform, which then forms the handle of the blown container 125. Details of the rotation of the mandrel 115 and details of the masking of the preform stem are discussed more fully with reference to fig. 10, 11 and 12.

A mold cavity 121 is mounted on the outer periphery of the fourth carousel 126. During the passage through the section of about 270 deg., the half-moulds 122 and 123 are rotated about their axes 127 to the closed position, after which the preforms 112 comprised in the half-moulds 122 and 123 are blown and biaxially stretched in a known manner so as to produce blown containers 125 with integral handles. The receptacle 125 is ejected as shown when the mold halves are opened in preparation for receiving a new preheated preform 112.

Referring to fig. 10, additional details of the mandrel 115 and handle shield 124 are shown, as well as the manner in which the mandrel 115 and handle shield 124 operate relative to the preform 112 as the preform 112 passes through the preheating tunnel 117 on the second carousel 116.

In one embodiment, the mandrel 115 is rotated by the belt drive 128 to complete about 4 full rotations of the mandrel 112 as it passes through the pre-heat tunnel 117.

At the same time, in the preheating tunnel 117, the handle shield 124 is lowered over the free end 129 of the handle stem 130, thereby completely shielding the handle stem 130, see fig. 12 for further details.

In a preferred form, as shown in fig. 12, the shield 124 is cylindrical except for a notched opening 131. The recessed opening 131 helps to ensure maximum shielding of the handle stem 130 and also helps to guide the boot 124 over the free end 129 of the stem 130.

The shield 124 is raised and lowered by shield support rods 132, the support rods 132 being suspended from cam followers 133 that are adapted to move on cams 134.

The shield support rod portion 132 rotates by the belt driver 135 to follow the rotation of the mandrel 115. As shown in the end view of fig. 11, the shield support rod 132 is offset relative to the cam follower 136 by fitting adjacent the outer periphery of the plate 137.

As cam follower 133 moves up cam 134, it pulls handle guard 124 up with it through a linkage consisting of guard support bar 132, plate 137 and cam follower bar 136.

The cam follower lever portion 136 includes a telescoping structure that allows for pivoting between its two telescoping members.

The handle shield 124 may include alternative shapes other than cylindrical, for example, may include an elliptical cross-section, although a cylindrical structure having a circular cross-section is preferred.

The handle shield 124 is preferably made of an insulating material (e.g., a ceramic material) and is preferably covered on an outer surface 138 with a heat reflective material that also reflects light in the ideal case.

In use, the reflective surface 138 reflects light and heat emitted from the heater 118, thereby performing two functions. The first function includes shielding the handle shaft 130 from heat. The second function is to reflect heat and light toward the portion of the preform closest to the handle stem 130 so that the portion is uniformly heated and not shielded by the stem 130.

In one particular form, the handle shield 124 may be cooled by blowing air or nitrogen gas thereto as the handle shield 124 is lifted from the preform 112. This helps prevent heat conduction by radiation or convection from building up within the cavity 129 of the shield 124.

Fig. 13-23 show details of a parison, a mold, and a container blown from the parison in the mold by the blow molding machine of fig. 9. Referring to fig. 13, in a preferred form, dimension a is greater than dimension B to prevent tangling of the preforms prior to loading into the chute 113.

It can be observed that in this form the upper end of the handle is located adjacent the locating ring. It is also noted that the preform stems, which subsequently form the handles of the blown containers, are supported within the mold halves throughout the blowing process. Instead, the walls of the container (including the portion of the container wall peripherally opposite the upper end of the handle stem) are free to blow within the confines of the mold.

Referring to fig. 24 to 34, these show a second form of preform, mould and resulting blown container in which the first unexpanded region 30 is relatively long in the axial direction and includes a portion 140, said portion 140 extending downwardly from the retaining ring 141 to and around at least the upper connecting portion of the handle stem 130, thereby forming a connection of the upper end of the handle stem 130 to the retaining ring 141. (best shown in fig. 24).

In this form, the portion of the preform wall circumferentially remote from the connection of the handle stem 130 to the preform 112 is at least partially expanded (see fig. 32 and 34). The expansion is relatively free of bi-directional expansion that occurs below the first and second non-expanded regions 30 and 31. The expansion significantly increases the strength and gas permeation resistance at least in the second unexpanded region 31, even though the strength and gas permeation resistance are not significantly increased in the first unexpanded region 30.

Container resistant to internal pressure

Referring to fig. 35-39, there is shown a container 150 with an integral handle 151 obtained by bi-directional blowing of the preform 152 of fig. 40 and 41.

In this example, as shown in fig. 36, the blown container 150 includes a discontinuous region 153. In this example, the discontinuous region 153 extends over the entire circumference of the container 150.

As shown in fig. 38, the discontinuous region 153 lies in a plane that is at an acute angle α to the horizontal plane XX.

The plane of the discontinuous region 153 is oriented such that the position through which it passes closest to the integral handle 151 is located between the first end 154 and the second end 155 of the handle 151.

In this example, the portion of the discontinuous region 153 furthest from the handle 151 lies in a plane XX passing through or near the connection region 156 where the second end 155 of the handle 151 is connected to the container 150.

As shown in fig. 35, the discontinuous region 153 is formed by significantly changing the wall orientation of the receptacle 150, wherein a first tangent line 157 of the upper wall portion 158 of the receptacle 150 and a second tangent line 159 of the lower wall portion 160 of the receptacle 150 intersect at an obtuse angle β, thereby forming a portion of the discontinuous region 153.

The discontinuous region 153 increases the strength of the container wall and thus resists deformation, particularly due to internal pressure that may be generated when the container is sealed (e.g., when the container comprises a carbonated beverage).

To assist in forming the discontinuous region 153, the preform 152 for the bi-directionally blown container 150 includes different wall thickness profiles, in this example in the form of a first wall profile 161, a second wall profile 162, and a third wall profile 163 spaced apart from one another by a first transition zone 164 and a second transition zone 165, as shown in fig. 40.

It can be observed that the wall thickness of the third wall profile 163 is greater than the wall thickness of the second wall profile 162, which in turn is greater than the wall thickness of the first wall profile 161.

In a bi-directional blowing operation, the second end 155 is connected to the container by deforming the container and surrounding the second end 155 of the handle 151. Second end 155 may include a bulbous portion including a bulbous portion of the type shown in fig. 2.

The preform 152 may be manufactured from PET material in accordance with the injection molding operation described previously herein.

Then, as a second stage of operation, the preform 152 is blown in a stretch blow molding machine so that its walls conform to the interior surfaces of the mold, as described earlier in this specification.

Connecting piece connecting handle

Referring to fig. 42 and 43, there is illustrated an alternative form of container and preform for making the container, which comprises the basic form of the composite integrally connected handle structure of the present invention.

Referring to fig. 42, the container 201 includes an integral handle 202 constructed and arranged as previously described except that the connection to the lower end of the container 201 is an integral connection formed by a connecting member (Tag)203 extending downwardly from the lower edge 204 of the broad portion of the handle 202 to a central circumferential portion 205 of the container 201 and is integrally connected to the container 201 therein. The lower edge 204 of the wide portion of the handle 202 includes a connecting portion 206, the connecting portion 206 merely resting on a surface of the container 201, rather than being integrally connected or otherwise connected to the surface of the container 201.

Fig. 43 shows a preform 207 for blowing the container 201 of fig. 42. The preform 207 is constructed in substantially the same manner as shown in fig. 40, except that the lower edge 204 of the handle 202 is integrally connected to the preform 207 by the connecting member 203 in the manner shown in fig. 43.

The preform 207 is blown into the container shown in fig. 42 using the process previously described with reference to fig. 10, 11 and 12.

Preform and container with composite integral handle

Referring to fig. 44, a preform 301 having a neck 302 and an expandable portion 303 located below the neck 302 is shown.

The stem of the previous example of this description is replaced by a ring 304, the ring 304 being made of the same material as the wall 305 of the preform 301. In this example, the loop 304 is integrally connected at its first end 306 to a first location 307 on the wall 305 and forming part of the wall 305.

The second end 308 of the ring 304 is integrally connected to the wall 305 at a second location 309.

The ring 304 and the preform are formed simultaneously in the same mold and are preferably formed from a PET plastic material.

In the present example, with reference to fig. 47, in the region of the wall 305 between the first position 307 and the second position 309, the charge of plastics material can be controlled differently depending on the position on the circumference of the wall 305 in this region, so as to produce the differential charge region 310 shown in fig. 47.

In this embodiment, the material charge is increased in region 310 directly between first location 307 and second location 309, while some material is removed in region 311, which is diametrically opposite region 310, as shown by the dotted outline.

Loading different amounts of material depending on the circumferential position on the wall 305 helps to control the wall thickness of the blown container 312 shown in fig. 45.

The container 312 may be blown in a two-stage process using the equipment and shielding principles described previously in this specification.

In this example, the area 310 between the first position 307 and the second position 309 remains substantially unchanged during the blowing process and can be considered as an extension of the neck 302 of the preform 301.

Fig. 46 shows an alternative configuration of the ring 313, which in this example still comprises an elongated rod-like structure with reinforcing ribs 314, but in this example also comprises a deflectable portion 315, the deflectable portion 315 being connected at one end to the end of the ring 313 by a first bridge portion 316 and at the other end integrally connected to the container wall 318 by a second bridge portion 317.

In this example, the second bridge portion 317 is similar in structure to the previously described connector 203 and provides the necessary flexible element. The first bridge parts 316 may have the same type of structure and be integrally formed when the preform is blown.

In use, during the second stage of blowing the container 319, it is observed that the container wall 318 integrally connected with the second bridge portion 317 moves during blowing, which movement is accommodated by the deflection of the deflectable portion 315 of the ring 313 about the first and second bridge portions 316, 317.

In production, with the aforementioned apparatus, the material can be moved differentially within the wall section, such that, for example, in the differential loading zone 310, the material closest to the inside of the container can be moved relative to the first and second locations 307, 309, while the material closest to the outside of the container is substantially stationary relative to the first and second locations 307, 309, thereby stabilizing the outer sidewall region during the second stage blowing step.

In production using a two-stage blow molding machine, it is important to have a sufficiently wide heating tunnel to allow the stem/ring protected preform to rotate. It is also important to be able to controllably shield the stem/ring portions of the preforms as they pass through the heating tunnel, and to be able to selectively shield portions of the preform walls between and below the stem/rings, thereby providing an important means of controlling the heat distribution throughout the preform just prior to insertion of the preform into the mold cavity for the second stage blow molding step.

In one particular form, a heat shield may be attached to the mandrel and into the mold cavity and retained within the cavity during the second stage blowing step.

Although a single handle has been shown in the embodiments described thus far, it should be noted that more than one handle may be provided on a given container in accordance with the principles described herein.

A preform 410 according to another embodiment of the invention is shown in a cross-sectional side view, in this example comprising a symmetrical thickening of the wall 411 of the preform 410 in a lower zone 412, said lower zone 412 extending just from the connection location 413 of the lower end 414 of the handle 415. In a second intermediate zone 416, located between the connection position 413 and the connection position 417 of the handle 415, the thickened thickness of the wall of the preform 410 is gradually reduced from a first thickness T1 to a second (thinner) thickness T2.

The thickening is symmetrical about the longitudinal axis TT of the preform 410 so as to controllably increase the material thickness of the blown container 418 (see fig. 50) in the corresponding intermediate zone 416, and also in the sub-zone 419 immediately below the connection location 413 of the lower end 414 of the handle. It is assumed that the increased thickness of the blown container in region 419 is caused by the flow of material from the intermediate region 416 to the sub-region 419 in the second stage of the blow molding process, thereby controlling the wall thickness of the material in region 419 of the blown container 418.

Fig. 51 and 52 provide additional views of the blown container 418. Fig. 51 more clearly shows the asymmetrical bulbous portion 420 offset relative to the handle 415 about the longitudinal axis TT.

Fig. 52 shows a star-shaped recess 421 in the bottom portion 422 of the container 418. As shown in fig. 50 and 52, the star-shaped recess includes a central circular recess 423 and a circular array of wedge-shaped recesses 424 extending from the recess 423.

As shown in fig. 50, in this example, the container 418 also includes a longitudinal depression 425 in the wall of the region 412, thereby increasing the strength of the blown wall portion in that region.

Second preferred embodiment of the improved two-stage process

According to a second series of preferred embodiments of the present invention, a stretch blow molding machine 510, as shown in FIG. 55, is used to stretch blow mold a PET resin preform 511, as shown in FIG. 53, to produce a container 512 with an integral handle, as shown in FIG. 54. The preform 511 and resulting container 512 are of the same type as shown and described in the applicant's co-pending patent applications including PCT/AU 98/01039.

First preferred embodiment of the second stage of the two-stage Process

In a preferred form, the stretch blow molding machine 510 shown in fig. 55 includes a chain driven conveyor 513 having a plurality of mandrels 514 mounted at substantially uniform intervals, each mandrel passing along a generally elliptical path through a different processing station of the stretch blow molding machine 510.

The preform 511 mounted on the core rod 514 passes sequentially from a loading station 515 to a heating station 516, to a stretch blow molding station 517, and then to an unloading station 518.

As shown in fig. 56-60, each mandrel 514 includes a sleeved shield 519, a perspective view of which sleeved shield 519 is shown in fig. 61.

The encasement shield 519 receives the handle stem 520 fitted to the preform 511 therein so as to shield the handle stem 520 from the heat applied by the radiant heater 521 as the preform is conveyed past the heating station 516 in the direction indicated by the arrow in fig. 55.

As the preforms 511 are conveyed past the heating station 516, the preforms 511 are rotated by a second chain drive 522 acting on a serrated outer peripheral portion (not shown) of each core rod 514. Since the rotational speed of the chain conveying drive mechanism 513 is different from the rotational speed of the second chain drive 522, the mandrel 514 is caused to rotate.

Upon entering the blow station 517, each preform 511 is raised above the top 523 of the core rod 514, allowing the cavity portion of the mold half 524 to engage around the bottom step portion 525 of the handle step portion 520 and the preform neck ring 526.

Notably, the half mold 524 includes a recess 527 that is adapted to receive the sleeved shield 519 therein when the half molds 524 are brought together, thereby covering and shielding the sleeved shield 519 from damage during the blow molding stage. During the blow molding process, the preform 511 is biaxially stretched by the stretching rod 528 and gas is injected into the interior of the preform 511 to conform the preform 511 to the mold cavity, thereby forming the container 512.

The mold halves 524 are then opened, causing the chain driven transport mechanism 513, which has temporarily stopped during the blow molding process, to rotate again, thereby bringing the blown container 512 to the unloading station 518 for removal by the forks 529.

Referring to fig. 62, there is shown a perspective view of a 16-cavity preform mold 610 adapted to be mounted in an injection molding machine (not shown) that injects PET611 (or a similar orientable plastic material) through an injection nozzle 612 (see fig. 70 and 71) into a preform cavity 613 that is formed when the mold is in a closed condition, as shown in fig. 66 and 67. The mold cavity is then opened as shown in fig. 69, forcing the split members 614 and 615 apart by cam 616, allowing the handled preform to be ejected when the sliding engagement members 617 are retracted.

On a 500 ton injection machine, the injection phase typically takes from 45 seconds to one minute, allowing 16 preforms to be produced at a time during this time.

According to a variant two-stage process, after ejection, the preform 511 is allowed to cool and solidify for at least 6 hours before being placed in the blow moulding machine described with reference to fig. 55 to 61. Ideally, the preform is allowed to cool to room temperature during this time, and more preferably, the preform is allowed to solidify for at least 24 hours before entering the blow molding machine, in order to ensure consistency in the preform structure and thus in the blowing process at the critical second stage.

A typical production rate of the blow molding machine shown in fig. 55 is approximately 1500 to 2000 blown containers per hour, matching the production rate of a 16 cavity preform mold.

Second preferred embodiment of the second stage of the two-stage Process

Referring to fig. 72-77, in another example of the second stage 700 of the two-stage process, a previously injection molded preform 712 undergoes the following stages:

2. handle orientation;

3. to a transfer support;

4. rotating through a heating stage;

5. blow molding

Handle orientation

The body portion 730 of the preform 712 must be heated to the desired degree of plasticity to enable the material in the preform body 730 to be biaxially oriented during the stretch blow molding process. However, neither the neck portion 729 nor the handle 713 should be biaxially stretch blow molded and must be shielded from excessive heat at the heating station to prevent their crystallization and the resulting loss of strength. Thus, as the preform 712 is conveyed through the heating stage 718, the handle 713 of the preform 712 is shielded by the shield 758 and the neck 729 is shielded by the cylindrical receptacle 761, as shown in fig. 76.

The orientation of the handle must be controlled before the preform enters the heating stage so that the thermal protective shield 758 can be properly mounted to the handle 713 of the preform 712. Furthermore, it is important that each preform 712 is fed to the forming tool 720 with its handle correctly oriented so that it fits correctly into the half-mould when it is closed during the blowing phase.

Referring to fig. 72 and 73, in a preferred form, the preforms 712 are fed from a suitable supply (e.g., a hopper or vibratory bowl 722) to a feeding track 724 at the loading station 714. The infeed track 724 is arranged to advance the preforms 712 by gravity, vibration or other linear delivery method along the infeed track 724 supported between parallel infeed track members 725 and 726 below a positioning ring 728, as shown in fig. 73.

During transport along the infeed track 724, the orientation of the preform handles 713 is preferably controlled by guide slots (not shown) to substantially prevent the handles from occupying directions approaching or at right angles to the direction of travel. The preforms 712 are thus constrained to advance along the infeed track 724 with the handle 713 generally toward the front or rear of the body 730. An outlet (not shown) at the end of the infeed track 724 controls the sequential ejection of individual preforms 712 from the end of the infeed track.

As shown in fig. 73 and 74, the preforms thus discharged from the infeed track 724 fall vertically into an orienting apparatus 732 fixed directly below the end of the infeed track 724. In a preferred form, the orienting device 732 shown in fig. 73 is comprised of a truncated cylindrical sleeve 734 having an inner diameter adapted to allow the preform cylindrical body 730 and the retaining ring 728 to slide freely therethrough. The sleeve 734 has a cut-out 736 in its wall, the cut-out 736 extending the length of the sleeve from a handle inlet 738 at an upper edge 749 of the sleeve 734 to a handle outlet 740 at a lower edge 741. The cutout has a width sufficient to allow the handle 713 of the preform 712 to slide therethrough.

The upper edges 745 and 743 of the sleeve 734 are formed to guide the handle 713 into the cutout 736. For this purpose, the upper edges 745 and 743 are formed to be steeply inclined from respective high points 744 and 744A diametrically opposite the handle entrance to the handle entrance 738 of the cutout 736. To ensure that the handle does not fall and get stuck at the highest point of the upper edges 743 and 745, the feed track 724 is arranged substantially at right angles to the radial position of the cutout 736. Thus, because the handle 713 is prevented from occupying this direction as the handle 713 is advanced along the feed track 724 as previously described, the handle 713 cannot contact the upper edges 743 and 745 at the highest point, but instead falls onto the orienting device with the handle contacting the sloped upper edge 743 or 745.

The beveled edges 743 and 745 slope from the highest points 744 and 744A down to the respective sides of the cutout 736, terminating in respective smooth rounded corners 748 and 749 at the handle entrance 738. The ramp is large enough to ensure that the handle 713 of the preform 712 slides along the sloped edge portion.

When the handle contacts the angled portion 743 or 745, the preform 712 dropped into the apparatus 732 and not aligned with the cutout 736 will rotate as it slides downward under its own weight until the handle 713 and the cutout 736 are aligned and the preform 712 falls smoothly through the apparatus.

Transferring to a conveyor system and heating stage

Fig. 74 shows the preferred form of the handle orientation and portion of the transfer to the heating stage of the blow molding machine. As described above, the preform 712 is shown falling into the orienting device 732.

An indexing table 750 is disposed directly beneath the apparatus 732, with a plurality of sets 752 provided at equal intervals around the periphery of the indexing table 750, with each successive set 752 being in alignment with the axis of the apparatus 732 at a respective index position of the indexing table 750. The harness 752 is adapted to receive the preform 712 and hold the preform 712 as follows: the orientation of handle 713 initially produced by apparatus 732 is maintained relative to each harness 752 during retention of the preforms within the harness. (Note that all of the kits shown in FIG. 74 are empty.)

As the preform 712 reaches the transfer station 754 with the stepping of the table 750, the preform is ejected upwardly out of the nest 752 supporting it for engagement with one of a series of mandrels 756 of the preform transfer system 716 operating between the loading station 714 and the blow molding tool 720. A preferred mandrel configuration with a preform is shown in fig. 75.

When the mandrel is inserted, the open neck 729 of the preform 712 is pushed over the resilient plug 759 in the cylindrical socket at the bottom of the mandrel. Plug 759 enters the open neck as an interference fit sufficient to support the weight of preform 712 within receptacle 761. The socket also serves to protect the neck 729 from excessive heat during the heating phase.

Heating table

Proper preheating of the preform 712 is important for the subsequent stretch blow molding stage. Proper distribution of heat to the preforms is complicated by the need to shield the preform handles 713 of the present invention and requires careful design of the arrangement of the heat shield 758 and heating elements.

Fig. 76 is a more detailed cross-sectional view of the preform 712 with the heat shield 758 installed. The core rod 756 and the retaining device for supporting the preform are not shown for clarity. It may be noted that the shield 758 for the handle 713 of the preform 712 is carefully shaped to shield the handle 713, but to allow heat from the heating element (as shown in fig. 77) to reach the area 770 of the preform body 730 between the upper and lower connection locations 772, 774 of the handle 713. The heat shield 758 includes side portions 776 (only one of the side portions 776 is visible in the cross-sectional view of fig. 76) that extend substantially on opposite sides of the handle 713. The side portions 776 extend from opposite edges of the spine element 778 that conforms to the shape of the upper portion of the handle and is attached to the mandrel receptacle 761. The shield opens below the handle to allow the preform and its handle to engage the core rod upwardly and then retract from the shield at the end of the heating phase.

To ensure optimal heat distribution, the sides 776 of the heat shield 758 are shaped to leave a gap 780 to allow heat penetration into the area 770 as the preform is rotated during transport through the heating stage. The size and shape of the gap 780 is empirically determined in conjunction with the optimal distribution of the heating elements 782 of the heating system shown in fig. 77.

Referring to fig. 77, the heating system 718 includes an array of heating elements 782 supported at the outer ends of the heating elements 782 by adjustable mounts 784 in a known manner for preheating preforms of conventional symmetrical containers.

However, in the present application, the heating elements 782 are arranged in the pattern shown in fig. 77 and the respective intensities of the heating elements are adjusted according to the handle and the particular energy density required to ensure that all portions of the preform 730 are heated to the desired plastic temperature as it passes through the array of heating elements.

In a first alternative preheating arrangement (not shown), the preform of the invention is again attached to the support core rod to pass through the heating station. However, in the present arrangement, each core rod carries an elongated cartridge heater coaxial with the axis of rotation of the core rod and the preform body portion, extending substantially the length of the preform body portion. The preform is thus heated from the inside. The cartridge heater may be divided into several individually controllable heating sections along its length so that the heating may be adjusted to accommodate any wall thickness variations of the preform body.

In a second alternative preheating arrangement (not shown), each preform is surrounded by two half-heating shells as it enters the heating phase. The heating mantle is connected to a separate conveyor system which drives the heating mantle to move the heating mantle synchronously with the mandrel. As the preforms exit the heating phase, the heating mantle is opened and the preforms are conveyed further to the blow-moulding tool. The heating mantle may be arranged to fit relatively tightly on the preform body, while the integrally attached handle is located substantially outside the heating mantle and is thus protected from preheating of the preform.

Rotate past the heating stage

To ensure uniform heating of the body 730, the preform 712 must be rotated as it passes over the plurality of heating elements 782 via the heating station, as shown in fig. 72 and 77. An essential feature of the mechanism that drives the rotation of the preform 712 is that the orientation of the handle at the end of the heating station 718 must ensure that the handle enters the blow tool 720 properly. Two preferred arrangements for achieving this result are described below.

First example

Each core rod 756 (shown in fig. 75) includes a fixture 760 for attachment to the transfer system 716. The conveyor system 716 may include a twin chain conveyor supported at each end by pairs of sprockets with the mandrels mounted in spaced relation between the chains. Bearings 762 in the mounts 760 allow the preform 712 and its handle to protect the heat shield 758 from rotation.

The sprocket or toothed pulley 764 engages a fixed rack or chain (not shown) of the conveyor system to cause the preforms to rotate as they pass through the heating station 718. The rack or chain is arranged along the lower leg of the twin strand conveyor along which the core rod conveys the preforms through the heating station. To maintain the orientation of the core rods in the preform loading and unloading stations, the core rods are provided with guide surfaces which slidingly engage fixed rails, thereby preventing rotation. The length and number of teeth of the rack, along with the pitch diameter of the toothed pulley 764, are designed to rotate the preform an integer number of turns so that the handle is oriented away from the end of the rack in the same direction as the initial orientation after insertion into the preform loading point.

Second example

The container of the present invention can be successfully blow molded in a conventional blow molding machine with appropriate modifications. Typically, the rotation of the preforms as they pass through the heating stations of these blow molding machines does not guarantee that the preforms have any particular orientation as they enter the blow molding tools. The preforms are typically supported on a mandrel holder which moves along an endless track system, with sprockets on the holder engaging with a chain or rack as the holder passes over the heater, causing the preforms to rotate. The sprocket and the preform attached to the mandrel holder are free to rotate when there is no contact with the rotation generating system of the heating station.

With conventional stretch blow molding machines, typically the transfer rail, carriage and mandrel assembly passes through a blow station and the resulting container is blown to be ejected from the support mandrel only when the container exits the forming tool. The conveyor system moves in steps, allowing the rack (or racks in the case of a multi-cavity tool) to remain stationary during the blowing cycle within the blow tool.

The disclosure herein includes a device for controlling the orientation of a mandrel used to blow containers of the present invention with integral handles on such conventional blow molding machines. The structure controls the orientation of the core rods as the preforms are mounted onto the core rods prior to or as they enter the heating station, and as the preforms are conveyed through the blow tooling.

To this end, each conventional rack of a standard stretch blow molding machine is retrofitted or replaced with a bracket that mounts spring-loaded locking pawls for engagement with notches on the bosses of the rack sprockets. The pawl is actuated to engage the recess and thereby lock the sprocket by a lever extending from the side of the bracket that contacts a fixed cam or ramp mounted adjacent the transfer rail.

The activation takes place at a position of the transfer infeed track before the cradle and the mandrel enter the blow-moulding tool. In which the sprocket is no longer in contact with the rotary drive system, i.e. the sprocket can rotate freely. After the pawls are activated, at a subsequent step stop of the conveyor system, an electrically driven friction wheel engages and rotates the sprocket until the recesses and spring loaded pawls are aligned. The pawl engages the recess to stop rotation of the sprocket. The core rod is then properly aligned so that the core rod and the handle of the preform enter the cavity of the blow tool.

The sprocket remains locked after the carriage is removed from the tool. The resulting blown container is ejected from the mandrel and the holder is stepped to a loading station to receive the pre-oriented preform as previously described. Before the carriage enters the heating station again, the lever of the control pawl comes into contact with a second fixed cam or ramp, which reverses the position of the lever and withdraws the pawl from the recess, allowing the blow-molding machine rotation system to control the rotation of the preforms as they pass through the heating station.

Blow molding

In said first example, the preforms are ejected from the mandrels of the heating station transfer system to a transfer system which carries each preform into the blow-moulding tool and maintains the orientation of the handle. In this arrangement, the handle is loaded into a separate cavity of the mould, for example as shown in figure 16. The same transfer system (which may include, for example, a twin strand conveyor) also transfers the blown container (or containers) away from the blow molding tool.

In said second example, the mandrel of a conventional but modified blow-moulding machine carries the preform through the blow-moulding tool, requiring the heat shield to be housed inside the moulding tool. The heat shield as shown in the example of fig. 75 and 76 is fixed relative to the mandrel and thus the cavity for the handle must also be sized to accommodate the heat shield in a position to cover the handle.

However, the upper and lower attachment locations 772, 774 of the handle 713 should be tightly confined within the blow tool to prevent them from moving during the stretching and blowing operations. At upper and lower attachment locations 772 and 774, the gap between the body 730 and the heat shield 758 is sufficient to shield those portions of the handle from excessive heat, but still allow suitable structure within the blow mold tool to engage and restrain those attachment locations of the handle when the tool is closed. A more preferred arrangement includes a mechanism (not shown) that lowers the preform relative to the heat shield by an amount sufficient to expose the upper attachment location 772 of the handle through a larger gap 780 in the side 776 of the shield 758. This arrangement then allows for better access to the restraining structure to restrain the handle by locating the lower attachment location 774 below the lower edge of the shield.

In an alternative arrangement (see, e.g., fig. 58), the heat shield is not rigidly attached to the mandrel receptacle 761, but is hinged to the mandrel receptacle 761. In this arrangement, when the tool is closed, a mechanism incorporated within the forming tool rotates the handle away from the heat shield so that the handle is tightly nested by the tool. The thermal shield is then housed in its own cavity, separated from the cavity of the handle of the container and the cavity of the final body shape.

It is worth noting that while the preform body region defined by the narrow strip between the two connection locations 772 and 774 of the handle 713 remains substantially stable during the stretch blowing of the container, the outer and inner surface layer regions laterally remote from the narrow strip are biaxially stretched. While the outer surface of the narrow band remains substantially stable, the walls of the narrow band between the handle attachment locations and the inner layers and surrounding areas together experience some flow and thinning when the plasticized material is subjected to stretching and blowing forces.

It is important that the portion of the preform that is to undergo biaxial stretching and blowing, i.e., all of the body portion 730 located below the neck or retaining ring 728, does not contact the walls of the molding cavity until it is forced to contact the walls of the molding cavity when the process of biaxial orientation of the preform material is substantially complete. To this end, the region between the two connection points 772 and 774 of the handle is initially not in contact with the walls of the moulding cavity when the tool is closed on the preform. Instead, a slight gap is provided between the outer surface of the preform body and the cavity wall, thereby ensuring that premature crystallization does not occur (e.g. in a cooling tool) and that a certain degree of material flow and bidirectional orientation occurs, in particular in the inner layer of the region between the connection locations.

The foregoing describes only some embodiments of the present invention and modifications may be made thereto by those skilled in the art without departing from the scope and spirit of the present invention.

Industrial applicability

Embodiments of the present invention may be used to manufacture containers made of orientable plastics material and incorporating a handle or similar gripping member as an integral part of the container.

Claims (13)

1. A heat shield for shielding an integrally formed handle of a preform in stretch blow molding of a container; forming said handle from a loop of orientable plastics material integrally connected to said preform at a first end and a second end; the heat shield includes side portions extending substantially on opposite sides of the handle; said side portions extending from a skeleton member connected to a core rod supporting said preform; the heat shield shields the handle from excessive heat when the body portion of the preform is preheated prior to entering the stretch blow molding tool.

2. The heat shield of claim 1 wherein the heat shield is coupled to each of a plurality of mandrels of a preform transfer system, each of the heat shields being adapted to at least partially enclose the handle of the preform.

3. The heat shield of claim 2 wherein the edges of the side portions are shaped to selectively protect the interconnected locations of the handles from excessive heat; portions of the side members are arranged to allow sufficient clearance to allow sufficient heat penetration into the body region of the preform between the interconnection locations.

4. The heat shield of claim 2, wherein the mandrels are evenly spaced along the endless transport system; the endless transfer system is driven in steps to remain stationary during a blowing cycle of the mandrel and heat shield within the blow molding tool.

5. The heat shield of claim 2, wherein each of the mandrels of the preform transfer system is adapted to rotate about an axis of the preform; each of the mandrels is brought into a predetermined orientation at a suitable subsequent indexing position of the indexing table to properly align the heat shield to receive the integrally formed handle of the preform therein.

6. The heat shield of claim 5, wherein the length of the preform transfer system and the rotation of the core rod and the heat shield are arranged to: the handle of each preform is in the predetermined orientation when the preforms are output from the mandrels and the heat shield.

7. The heat shield of claim 5 wherein the mandrel and the handle of the heat shield and the preform are rotated to the predetermined orientation before the mandrel and the heat shield and the preform enter the blow tool.

8. The heat shield of claim 7 wherein the preforms are rotated as they are conveyed by the preform transport system past the plurality of preform heating elements.

9. The heat shield of any of claims 1-8, wherein the preform is inserted into the core rod in a preform loading position such that the handle is located within the heat shield.

10. The heat shield of claim 9, wherein the conveyor of the preform transfer system extends between the preform loading position and the preform unloading position.

11. The heat shield of claim 10, wherein each mandrel is forced to rotate between the loading position and the unloading position; the rotation is caused by contact between a toothed pulley of the mandrel and a rack extending between the loading position and the unloading position.

12. The heat shield of claim 10, wherein the mandrel completes a full number of revolutions between the loading position and the unloading position such that the orientation of the shield at the unloading position and the loading position are substantially the same.

13. The heat shield of any one of claims 5-7 wherein the handle and the heat shield are placed within a cavity for the handle and the preform within the blow molding tool.