WO2006055793A1

WO2006055793A1 - Multi-container array and method of making same

Info

Publication number: WO2006055793A1
Application number: PCT/US2005/041851
Authority: WO
Inventors: Roy N. Krohn; David A. Kesselman; Nicole Korpanty
Original assignee: Graham Packaging Co LP
Current assignee: Graham Packaging Co LP
Priority date: 2004-11-18
Filing date: 2005-11-18
Publication date: 2006-05-26
Anticipated expiration: 2007-05-18
Also published as: MX2007006055A

Abstract

An array of extusion blow molded plastic containers can be prepared from a mold having a first mold cavity (302) for blow molding a first container (402), a second mold cavity (304) for blow molding a second container (404), and a manifold cavity (306), continuous with the first and second mold cavities, for blow molding a manifold (406). The mold includes a needle inlet (318) positioned for blowing a gas into the manifold cavity (306). The longitudinal axis (ACl) of the first mold cavity and the longitudinal axis (AC2) of the second mold cavity are non-parallel to a longitudinal axis (AM) of the manifold cavity. The longitudinal axis (AM) of the manifold cavity extends in a direction that is generally parallel to the direction in which a parison is inserted between the mold halves. The array can be prepared from a single parison and a single blow needle.

Description

Multi-Container Array and Method of Making Same

BACKGROUND OF THE INVENTION

Field of the Invention

[0001] The present invention relates generally to an array of containers, and more particularly to an array of containers extending from a central manifold prepared by extrusion blow molding. Related Art

[0002] The use of plastic containers for packaging foods and other products has become commonplace. Plastic containers are most commonly manufactured by blow molding processes, for example, extrusion blow molding. Modern blow molding machinery is designed to efficiently manufacture a large number of containers in a relatively short time. However, blow molding machinery frequently use a fixed number of molds of only a specific size. As the container to be molded decreases in size, the number of containers that can be blown in a single cycle of the blow molding machine can not be increased by adding more, smaller molds. Thus, other methods must be used to increase the number of containers that can be manufactured in a given time.

[0003] FIG. 1 depicts a wheel type blow molding machine. The polymer to be used to manufacture a container is loaded into a hopper 102, frequently in the form of beads. The resin is conveyed along an extruder 104, where it is melted into a molten form and fed into a continuous extrusion head 106. The extrusion head 106 may consist of multiple parison injectors through which the molten polymer is extruded. Each parison injector produces a molten tube of polymer, or parison, that is positioned between an open, i.e. separated, pair of mold halves. In the illustrated blow molding machine, the molten parison is extruded in an upward direction as the wheel rotates in the direction of the arrow 108. The illustrated wheel contains twelve molds 110. After the parison is extruded and injected between the mold halves, the mold halves close about the parison and cooperate to provide a cavity into which the parison is blown to form the container. After allowing some time for cooling, as the wheel rotates, the mold halves open to release a container, which typically falls onto a conveyor and is transported to a trimmer for removing scrap material.

[0004] In the illustrated wheel, the size and number of molds is fixed. If smaller containers are to be manufactured, either the size of the mold cavity must be reduced, which is often not possible, or a way to blow multiple containers in a single mold must be devised. In existing methods of making multiple containers in a single mold, the container axes are collinear and parallel to the direction in which the mold moves, i.e. the parison is extruded along the central axis of the mold. Thus, a single parison can yield, at most, two containers. Further, the containers are blown through a needle positioned in a moil located between the two containers, in order to avoid piercing the containers. This again limits the number of containers that can be blown from a single parison to two.

[0005] FIG. 2 illustrates a known method of manufacturing multiple containers in a single mold, as disclosed in U.S. Patent No. 6,709, 261 to Cargile et al., of common assignee of the present application, which is incorporated by reference herein in its entirety. FIG. 2A depicts a side view of a mold 200 and its position relative to the parison injectors 208. According to the method depicted, the mold contains two pairs of container forming cavities, each pair of which is provided with a single parison from a separate parison injector. Considering one of the pairs of container cavities, the two container cavities 202, 204 are joined at what will form the top ends of the containers through a moil region 206, which is a scrap region of the container. As can be seen, the longitudinal axis of the first container cavity 202 is collinear with the longitudinal axis of the second container cavity 204. The longitudinal axis of each container cavity is aligned with a single parison injector and parallel to the direction Dp in which the parison will be extruded. The mold cavities are located in the mold parallel to the side that is along the circumference of the wheel of the blow molding machine. Because of the arrangement of the containers, the mold is limited in that only two cavities can be aligned with a single parison in a mouth to mouth configuration. The alignment of the cavity with the parison injector is most evident in the top view of FIG. 2B, which shows a pair of mold halves 210, 212 and the position relative to the extrusion heads 208. The resultant article, shown in FIG. 2C, is a container log 214, that consists of two containers 216, 218 joined at the moil region 220. The container log 214 can also include additional scrap or flash 222 at the base of each container 216, 218. After molding, the flash 222 is removed, and each container is cut from the moil 220 to provide two containers.

[0006] Using the configuration depicted in FIG. 2, the number of containers that can be formed in a single mold is limited by the number of pairs of container forming cavities that can be positioned side-by-side and in line with a parison injector. In a typical mold, size constraints limit the number of pairs of containers and parisons inserted in a mold to two. Thus, in this conventional method of blowing multiple containers in a single mold, it is very difficult to blow more than four containers in a mold.

[0007] There thus remains a need for methods to blow mold multiple containers in a single blow mold, while preferably providing a single parison to the mold.

BRIEF SUMMARY OF THE INVENTION

[0008] In summary, the invention provides an array of containers and a method of making an array of containers in a single mold, where the container axes are non-parallel to the direction in which the mold moves. The present invention uses a manifold that interconnects with each container of the array. The longitudinal axis of the manifold is aligned in a direction parallel to the direction in which the parison is extruded. During manufacture, air is blown into the manifold, inflating each of the plurality of containers in the array.

[0009] This invention differs from the prior art in modifications which were not previously known or suggested. In existing methods of making multiple containers in a single mold, the parison is extruded along the central axis of the mold cavity. The present invention uses a manifold that interconnects with multiple container cavities in an array. The longitudinal axis of the manifold is aligned in a direction parallel to the direction in which the parison is extruded and the axes of the containers are non-parallel to the direction of parison extrusion.

[0010] This invention provides advantages that were not previously realized by providing a method of forming multiple containers, for example more than two containers, from a single parison. The invention also provides a means of making more than four containers in a single mold, from a single parison with a single blow needle.

[0011] An advantage of the present invention is that the new position of the container cavities only requires the vertical distance of its diameter or width. This leaves space to position more containers side by side. The longer the cord length of a mold is, the more cavities may be placed into it.

[0012] Accordingly, an array of blow molded plastic containers can be prepared from a mold that has a first mold cavity for blow molding a first container a second mold cavity for blow molding a second container, and a manifold cavity for blow molding a manifold. The manifold cavity is continuous with the first mold cavity and the second mold cavity. A needle inlet is positioned for blowing a gas into the manifold channel. A longitudinal axis of the first mold cavity and a longitudinal axis of the second mold cavity are each non-parallel to a longitudinal axis of the manifold cavity. The longitudinal axis of the manifold cavity is generally parallel to the direction along which a parison is extruded when the mold is used in a blow molding process. The longitudinal axis of the first mold cavity, the longitudinal axis of the second mold cavity and the longitudinal axis of the manifold channel can be substantially co-planar. The longitudinal axis of the first mold cavity can be, for example perpendicular to the longitudinal axis of the manifold cavity. The longitudinal axis of the first mold cavity can be generally perpendicular to the direction along which a parison is extruded when the mold is used in a blow molding process. The molds can be used in a shuttle blow molding machine or a wheel type extrusion blow molding machine.

[0013] Using such a mold, an array of containers can be prepared. The container array includes a first container, a second container and a manifold connecting the first container to the second container. The longitudinal axis of the first container and the longitudinal axis of the second container each extend radially from the longitudinal axis of the manifold. The longitudinal axis of the first container and the longitudinal axis of the second container intersect the longitudinal axis of the manifold at points that are axially displaced from one another along the longitudinal axis of the manifold. Each container of the array has a base end, a finish end, and a sidewall therebetween, and each container is connected to the manifold at the finish end. The first container and the second container can be arranged side-by-side and can be parallel to one another and perpendicular to the longitudinal axis of the manifold. The longitudinal axis of the first container and the longitudinal axis of the second container can extend from the longitudinal axis of the manifold in opposite directions and extend at an angle that is 180° from the longitudinal axis of the second container. The manifold has a blow hole formed during a blow molding process, such as an extrusion blow molding process. The longitudinal axis of the first container and the second container can extend radially, or outwardly, from the longitudinal axis of the manifold, such that the longitudinal axis of the first container is non-collinear with the longitudinal axis of the second container. The array can be prepared from a single parison inflated with a single blow needle.

[0014] The method for blow molding the array from the mold includes extruding a parison between two mold halves in a direction generally parallel to the longitudinal axis of the manifold cavity, closing the mold halves, inserting a blow needle through the needle inlet to pierce the parison; and blowing air though the blow needle to substantially simultaneously form the first container and the second container. The parison can be extruded in a direction which is generally perpendicular to the longitudinal axis of the first mold cavity and the longitudinal axis of the second mold cavity. The method can also include opening the mold halves to remove the first and second containers from the mold and providing a container array. A container can be separated from the container array and the excess plastic trimmed from the container. The method can use a single parison and a single blow needle.

[0015] Further objectives and advantages, as well as the structure and function of preferred embodiments will become apparent from a consideration of the description, drawings, and examples.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The foregoing and other features and advantages of the invention will be apparent from the following, more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings wherein like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. Further, in general, for FIGS. 3-6, related features are given similar reference numbers where the first digit represents the Figure number and the last two digits represent the feature. For example reference numerals 302, 402, 502 and 602 identify related features in FIGS. 3, 4, 5 and 6, respectively. [0017] FIG. 1 depicts a typical extrusion blow molding wheel;

[0018] FIG. 2 depicts a dual parison blow mold;

[0019] FIG. 3 depicts a front view of a mold half according to an exemplary embodiment of the present invention;

[0020] FIG. 4 depicts an array of containers according to an exemplary embodiment of the present invention;

[0021] FIG. 5 depicts a mold half according to another exemplary embodiment of the present invention;

[0022] FIG. 6 depicts an array of containers according to another exemplary embodiment of the present invention; [0023] FIG. 7 is a schematic representation of various arrangements of container cavities in a mold; and [0024] FIG. 8 illustrates cross sectional views of head tooling that can be used in producing the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0025] Embodiments of the invention are discussed in detail below. In describing embodiments, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected. While specific exemplary embodiments are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations can be used without parting from the spirit and scope of the invention. All references cited herein are incorporated by reference as if each had been individually incorporated.

[0026] In order to produce more small capacity containers more rapidly on a blow molding machine according to the present invention, the position of the container cavities are rotated from the typical vertical position relative to the parison injectors, to a more horizontal position. Although generally described herein for use in an extrusion blow molding machine and, more particularly, a wheel type extrusion blow molding machine, the molds and container arrays described herein can be used in or prepared from other blow molding machines, for example a shuttle blow molding machine.

[0027] The mold is constructed mostly as any other mold, with the exception of the moldface, where the cavities are placed. The cavities are arranged in a side-by-side manner and can be perpendicular to the long side of the mold. Above and along the necks, at an edge of the mold, is located a long manifold, i.e., a blow channel, which is supplied with blow air from one blow cylinder and needle. The cavities have pinches along the neck and sides resulting in flash around all of the internal containers. Only one parison is required to produce as many as 5-6 containers per mold, or more containers per mold if the container diameter is sufficiently small. [0028] Another method of increasing the production of small diameter, but shorter containers, is to position the manifold or blow channel at the center of the mold and supply each connected cavity, with air through the channel. Using this configuration, as many as 10-16 small containers can be produced in a mold from a single parison, or more containers per mold can be produced if the container diameter is sufficiently small. [0029] To this end, FIG. 3A depicts a frontal view of a mold half 300a according to the present invention. FIG. 3B depicts a pair of mold halves 300a, 300b together to form a cavity of the mold. The molds can be used in various types of blow molding machines, for example, a shuttle blow molding machine or a wheel-type extrusion blow molding machine.

[0030] The mold half 300a includes a first cavity 302 corresponding to a first container to be produced and a second mold cavity 304 corresponding to a second container to be blow molded. The two container cavities 302, 304 are joined at the finish forming end 320 to a manifold channel 306 that will form a portion of the manifold cavity 308 depicted in FIG. 3B. The mold 300a includes an outer edge 310, or long side, which can be positioned in a wheel type extrusion blow molding apparatus along the outer circumference of the wheel holding the molds, and an inner edge 312 which can be located along the inner circumference of a wheel in a wheel type blow molding machine. As the mold moves, for example, by rotating within a wheel, the parison is extruded in a direction indicated by the arrow P_D. The mold half 300a includes a needle channel 314 into which a blow needle can be inserted, as well as a cylinder block cavity 316 in which a cylinder block can be positioned for holding the blow needle. As will be apparent, the manifold channel 306 includes an inlet 318 through which a blow needle will be inserted, ultimately giving rise to a blow hole in the manifold formed in an array of containers. (See FIG. 4A). Each of the two container cavities 302, 304 has an associated longitudinal axis Ac₁, Ac₂ respectively. The manifold channel 306 has an associated longitudinal axis A_M. The longitudinal axis of the manifold AM is located generally parallel to the direction P_D in which the parison will be extruded into the blow mold. The longitudinal axis of each container cavity Ac₁, Ac₂ is non-parallel to the manifold axis AM- The longitudinal axes of the container cavities extend radially from manifold axis AM- AS used herein, radially means that the longitudinal axis of each container cavity extends outwardly from the longitudinal axis of the manifold channel, but not necessarily perpendicular to the longitudinal axis of the manifold channel. In the illustrated embodiment, the longitudinal axes of the container cavities are approximately perpendicular to the longitudinal axis of the manifold channel.

[0031] Each of the container cavities 302, 304 is continuous with the manifold channel 306. More particularly, the container cavities are connected through the finish forming end 320 to the manifold channel 306 through a moil forming region 322. Extending from the finish forming end 320 of the container cavities is a sidewall forming portion 324 and a base forming portion 326. The moil forming region 322 of each container cavity has a continuous cavity inlet channel 328 which is continuous with the manifold channel 306. The mold half 300a can also include a body flash pocket 330 located between adjacent containers for accepting excess plastic material from the parison that is between the container cavities. A tail flash pocket 332 can also be present beyond the base forming portion of each container cavity for accepting excess plastic material. Along the parting line of the mold 334 on the side of the manifold channel opposite of the container cavities is a manifold flash pocket 336 for accepting excess plastic material from the manifold. As can be seen in FIG. 3B, the molds join along a parting ling 334 and the tail flash pocket 332 is present along that parting line. In the embodiment illustrated in FIG. 3, the longitudinal axes of the container cavities are parallel. Further, the longitudinal axes of the container cavities and the manifold channel are co-planar.

[0032] As illustrated in FIG. 3, the mold half according to the present invention can be utilized to mold a series of six containers. Depending on container diameter, more or fewer containers can be molded in a single mold. The containers in this configuration are relatively tall, i.e. their height is substantially greater than their width. The container height that is possible using such a mold, is limited only by the distance between the outer mold edge 310 and inner mold edge 312, i.e., the width of a mold, that can be placed in a particular wheel blow molding apparatus or other blow molding apparatus. The number of containers that can be molded in such a blow mold is limited by the length of the mold and the diameter of the container desired to be produced. Should a larger diameter container be desired, fewer containers could be simultaneously molded. If the containers are more narrow, more than six containers can be formed in a single mold. As can be further observed from the present invention, all of the containers that are molded in such a mold half are prepared from a single parison. Thus, more than two containers can be molded from a single parison and, as shown in the illustrated arrangement of FIG. 3, more than four containers can be molded in a single mold from a single parison with a single blow needle.

[0033] Using the mold depicted in FIG. 3, an array of containers as illustrated in FIG. 4 can be produced. FIG. 4A is a front view of an array of containers prepared from the mold shown in FIG. 3. FIG. 4B is an end view of an array of containers prepared from the mold depicted in FIG. 3. As seen in FIG. 4A, the array of containers includes a first container 402 and second container 404. The first container 402 has a longitudinal axis Aa and the second container 404 has a longitudinal axis Ac₂. The container array 400 also includes a manifold 406 that is hollow and was blown from the portion of a parison in the manifold cavity 306 of the mold shown in FIG. 3. The hollow portion of the manifold 406 is connected to the first container 402 and second container 404 in the region of the moil 422 located at the finish end 420 of the containers. That is, the cavity of the manifold 406 is connected to the interior of each of the containers 402, 404 by an inlet 428 at the top of each container. The longitudinal axis of the first container Ac₁ and the longitudinal axis of the second container Ac₂ each extend radially from the longitudinal axis A_M of the manifold. The point of intersection of the longitudinal axis of the first container Aa with the longitudinal axis of the manifold A_M and the point of intersection of the longitudinal axis of the second container Ac₂ with the longitudinal axis of the manifold A_M are axially spaced along the longitudinal axis of the manifold A_M- Thus, unlike the prior art, the longitudinal axes of the containers Ac₁, Ac₂ are not collinear. In the pictured embodiment, the longitudinal axis of the containers are parallel; however, as described further below, they need not be parallel to one another. As a result of being non-collinear, the first container 402 and second container 404 are arranged in a side-by-side manner. Because the array 400 according to the invention is manufactured by an extrusion blow molding process, the manifold 406 has a blow hole 418 present where the blow needle entered the channel in order to blow mold the manifold and the containers.

[0034] Interspersed between and around the containers of the array is a body flash 430. Extending beyond the bases of the containers, is the tail flash 432. A manifold flash region 436 extends from the manifold on a side opposite the containers. Within the body flash portion, can be present one or more knock out tabs 440 which are used for pushing the blow molded array out of the mold in a method that is generally known in the art. It is thus apparent to a person skilled in the art viewing an array according to the present invention that the array was extrusion blow molded from a single parison with the blow molding needle entering into the manifold to blow mold all of the containers of the array in a substantially simultaneous manner.

[0035] In order to complete the preparation of a container according to the invention, the containers making up the array 400 must be separated. Several steps are required for this process, which are similar to processes known in the art in the extrusion blow molding manufacturing of containers. These steps need not be carried out in any particular order. Separation and isolation of a container includes removal of the tail flash 432; separation of the manifold 406 from the containers, which may be accomplished either by first trimming the containers at the manifold near the inlet or cutting the containers away at the position where the moil meets the finish end of the containers; separation of the containers from one another by cutting the body flash 430 in a region between the containers; and trimming the body flash 430 away from the individual containers. Persons skilled in the art will be able to modify standard cutting and trimming equipment in view of this specification in order to accomplish separation of the containers.

[0036] The arrays of the present invention can be prepared in any type of blow molding machine or apparatus. These include, but are not limited to, shuttle blow molding machines and wheel blow molding machines. According to the present invention, a method for blow molding a plastic container includes positioning a hollow parison between two mold halves 300a, 300b in which each mold half includes a first mold cavity 302 for blow molding a first container a second mold cavity 304 for blow molding a second container and a manifold cavity 306 for blow molding a manifold wherein the cavity is continuous with the mold cavities for the containers. The mold cavities for the containers extend radially from the longitudinal axis of the manifold cavity and intersect the longitudinal axis of the manifold channel A_M at points which are axially displaced from one another. The longitudinal axis of the manifold channel AM is non-collinear with the longitudinal axis of each of the container cavities Ac₁, Ac₂. The longitudinal axes of each container cavity Ac₁, Ac₂ can be perpendicular to the longitudinal axis of the manifold and can be parallel to and coplanar with one another. The parison is positioned such that its longitudinal axis is generally parallel to the longitudinal axis of the manifold channel A_M- The longitudinal axes of the containers are non-parallel to the longitudinal axis of the parison.

[0037] In order to improve material distribution when blow molding an array of containers as described herein, it may be advantageous to form the parison with an elliptical rather than a round cross section. Further, because of the width of the array forming cavities across the mold, it may be necessary to modify the head tooling and die. A suitably modified configuration is illustrated in FIG. 8. FIGS. 8 A and 8B are sections through the head tooling 800 taken along the major and minor axes of the elliptical die pin 802, respectively. The elliptical die pin 802 may require head tooling that is larger than the standard die pin bushing size allows. To accommodate this larger die pin, the bushing is split in the transverse direction to the center line of polymer flow, in order to be able to install a bushing hold-down ring. The modified bushing, after reconstruction, consists of the bushing body 804 and an upper portion or bushing cap 806. The bushing cap 806 increases the overall size of the bushing to accommodate the necessary increase in tooling, and is fastened to the bushing body 804 by socket head cap screws 808. The internal structure of this head tooling is thus divergent and elliptical. The elliptical die pin 802 and bushing cap 806 are separated by converging angles to facilitate the programming of the parison. The programming, of course, is made possible by the vertical movement of the die pin 802 relative to the stationary bushing, and can be used to minimize the material between containers in the array. Use of this modified head tooling allows for extrusion of a wide parison that can be used to prepare an array of containers according to the present invention.

[0038] After the parison is positioned between the mold halves, the mold halves close and a blow needle is inserted into the parison through a position in the manifold cavity channel 306. Air or some other inflating gas is then blown through the blow needle into the manifold cavity inflating the parison within the manifold cavity 308 and the plurality of containers in the container cavities in a substantially simultaneous manner. As is known in the art, the parison may be partially inflated prior to closing of the mold halves. After sufficient time to allow some cooling, the mold is opened, i.e. the mold halves separate, and the array of containers 400 exits the mold. The array of containers, together with the associated flash, is transported to a trimming operation. In the trimming operation, the containers are separated from the manifold 406, the moil for each container is separated from the containers, the body flash 430 is cut between the containers to give rise to a container surrounded by flash, and the flash, including the body flash 430 and tail flash 432 , is trimmed from the containers. Thus, from the array of containers 400, a plurality of individual containers is obtained.

[0039] FIG. 5 illustrates an alternative mold half according to the present invention. The mold of FIG. 5A is a frontal view of the mold half 500a and FIG. 5B is an end view of a pair of mold halves 500a, 500b joined together for blow molding an array of containers. The configuration of FIG. 5 can be used in situations were a number of shorter containers are to be manufactured simultaneously in a single blow mold. The blow mold half 500a of FIG. 5 includes a first container mold cavity 502 and a second container mold cavity 504 with related longitudinal axes Ac₁, Ac₂, respectively. The container cavities extend radially from a manifold channel 506 along its longitudinal axis AM- When two such molds 500a, 500b are joined together, a manifold cavity 508 is created. As with the mold half 300a of FIG. 3, the longitudinal axis of the first container cavity A_C1 and the longitudinal axis of the second container cavity A_C2 extend radially from the longitudinal axis of the manifold A_M. Further, the longitudinal axes of the container cavities are not collinear with one another nor with the longitudinal axis A_M of the manifold channel 506. The point of intersection of the longitudinal axis of the first container Ac₁ with the longitudinal axis of the manifold A_M and the point of intersection of the longitudinal axis of the second container Ac₂ with the longitudinal axis A_M of the manifold are axially spaced along the longitudinal axis of the manifold A_M- The mold half 500a includes a needle channel 514 for positioning a blow needle and a cylinder block cavity 516 for holding the cylinder block of the blow needle. An inlet 518 j oins the needle channel 514 with the manifold channel 506 for inserting the blow needle.

[0040] Li the illustrated embodiment of FIG. 5, in addition to being axially spaced along the longitudinal axis of the manifold, the container cavities 502 and 504 extend from the longitudinal axis of the manifold A_M in opposite directions. That is, the longitudinal axis of the first container cavity Ac₁ and the longitudinal axis of the second container cavity Ac₂ extend towards the inner edge 512 and outer edge 510 of the mold half 500a, respectively. In other words, the longitudinal axis of the first container cavity Ac₁ and the longitudinal axis of the second container cavity Ac₂ extend in directions that are 180° from one another. Additionally, in the illustrated embodiment, the container forming cavity 502 has situated directly across from it on an opposite side of the manifold channel 306 a container forming cavity 502'. In this case, the longitudinal axes of these two container forming cavities are collinear, much like the mold halves in the prior art illustrated in FIG. 2. However, this arrangement differs in that the longitudinal axes of the container cavities are arranged in a direction that is not parallel to the direction in which the parison would be extruded P_D- In the illustrated embodiment, the longitudinal axes of the two container forming cavities are perpendicular to the direction in which the parison would be extruded. Further, the layout of container cavities and the mold as illustrated in FIG. 5 allows for additional container cavities to be positioned in a side-by-side manner to each of these two container cavities with collinear axes. Thus, more than two containers can be prepared from a single parison and only one blow needle is required for blow molding multiple containers. In the illustrated mold, there are eight container forming cavities. Depending on the size of the containers, additional mold forming cavities could be present so that such a single mold could make ten or even twelve containers in a single mold from a single parison.

[0041] Because the manifold 506 in the embodiment illustrated in FIG. 5 is located in a central portion of the mold, there is no manifold flash pocket present. However, there are two tail flash pockets 532 located on opposite sides of the mold. After blow molding, the excess plastic material from the parison that is present in each of these tail flash pockets 532 would be trimmed from the containers that are formed.

[0042] FIG. 6 illustrates an array of containers 600 that would result from blow molding a parison within the blow mold illustrated in FIG. 5. Each of the containers in the array 600 and the array itself includes structural aspects derived from the mold half of FIG. 5. Thus, a first container 602 is formed within the container forming cavity 502; a second container 604 is formed from the container forming cavity 504 and a manifold 606 is formed from the manifold channel 506. The other structural features of the array are referenced with respect to the numbering of FIG. 5 as described above. As with the array of FIG. 4, the container array of FIG. 6 contains a single blow hole 618 in the manifold 606. This is evidence of the manner in which the array was prepared from a single parison. The array of FIG. 6 contains four knock out tabs 640. The number and location of knock out tabs depends upon the mold that is used and what is necessary to remove the array from the cavity after the array is blow molded. The arrangement and location of knock out tabs can be varied using methods for locating knock out hubs that are known in the art for molds that blow mold a single or multiple containers.

[0043] As previously described, it is not necessary that the container axes extend perpendicular to the longitudinal axis of the manifold. FIG. 7 illustrates schematically several alternative arrangements of the container axes about the manifold axes in a container array of mold half. In FIG. 7, A_M schematically represents the longitudinal axis of the manifold or manifold channel and each Ac represents a longitudinal axis of a container or container cavity. For example, in FIG. 7 A, the longitudinal axes of the containers Ac extend radially from the longitudinal axis of the manifold A_M at an angle other than 90° degrees. In this arrangement, the longitudinal axis of the manifold A_M and the longitudinal axes of the containers Ac are arranged in what might be considered a herring bone manner. For longer containers, as illustrated in FIG. 7B, the longitudinal axes of the containers Ac may extend from only one side of the longitudinal axis of the manifold AM radially and nonperpendicular to the manifold axis A_M and the manifold channel positioned more closely to an edge of the mold.

[0044] FIG. 7C illustrates yet another possible arrangement which takes advantage of the approximately trapezoidal shape of the mold. In this embodiment, the longitudinal axes of the containers Ac extend at varying angles from the longitudinal axis of the manifold A_M in a ray like pattern. Thus, the angle formed between the longitudinal axis of the manifold A_M and the longitudinal axes of the containers at the ends of the mold are more closely parallel to the leading edge M_L trailing edge Mj of the mold, respectively. The longitudinal axes of the internal containers extend more nearly perpendicular to the longitudinal axis of the manifold A_M. [0045] FIG. 7D illustrates that, even when the containers are present on opposites sides of the manifold, the containers need not be located directly across from one another. This arrangement again takes advantage of the trapezoidal shape of the mold and allows a larger number of containers to be molded on the side toward the outer mold edge 710 while having fewer containers cavities on the side of the inner mold edge 712. Other arrangement of containers relative to the manifold are possible. The containers can be arranged in order to maximize the number of the containers in the mold while taking into account the container width and height. Trimming equipment would necessarily need to be modified in order to effectively separate the containers in the arrays produced from the arrangements of FIG. 7. [0046] Using the method and mold halves described herein, the number of containers that can be blow molded in a single cycle of a wheel type extrusion blow molding machine can be significantly increased. For example, considering a twelve station blow molding machine, i.e. a machine with twelve molds, a maximum of twelve containers can be formed in a single cycle of the machine. Using existing methods for blow molding multiple containers in a single mold, up to 24 containers could be blow molded from a machine with one parison injector or, if two parison injectors are used then a total of four containers per mold or 48 containers could be molded per cycle of the wheel. Of course, there are associated costs involved with adding an additional parison injector to such a system. Using the present invention, multiple containers can be blow molded from a single mold while providing only one parison injector to each mold. Therefore, even if only four containers were molded per mold, for a total of 48 containers per cycle of a wheel, a cost savings would be realized in only having to provide one parison injector and associated hardware. However, the present invention allows for even more containers to be molded in a single mold. For example, the array of FIG. 4 which includes six containers per mold would give rise to a total of 72 containers in each cycle of the blow molding wheel, while still requiring only a single parison injector.

[0047] For smaller containers such as in the array of FIG. 6, eight containers can be blow molded in a single mold from a single parison. This would therefore yield 96 containers from a single cycle of the blow molding machine, a four-fold increase from existing dual parison technology and an eight-fold increase from single parison technology. As indicated above, even more containers can be manufactured from a single mold if those containers are smaller. For example, up to twelve small containers could be manufactured in a single blow mold yielding 144 containers per cycle of the blow molding wheel without adding a second parison injector and associated hardware. Thus, the present invention represents a way of reducing per container cost by manufacturing more containers without having to modify the parison forming mechanism of blow molding machine. Cost savings and efficiency are also significantly increased by the ability to blow mold a much larger number of containers per blow molding cycle and therefore per unit time. Thus, by providing container axes that are non- parallel to the direction of parison extrusion and having the containers all blow molded from a single manifold, significant cost savings can be realized and efficiency and manufacturing rate can be significantly increased.

[0048] The embodiments illustrated and discussed in this specification are intended only to teach those skilled in the art the best way known to the inventors to make and use the invention. Nothing in this specification should be considered as limiting the scope of the present invention. AU examples presented are representative and non-limiting. The above-described embodiments of the invention may be modified or varied, without departing from the invention, as appreciated by those skilled in the art in light of the above teachings. It is therefore to be understood that, within the scope of the claims and their equivalents, the invention may be practiced otherwise than as specifically described.

Claims

WHAT IS CLAIMED IS:

1. An array of containers comprising: a first container having a longitudinal axis; a second container having a longitudinal axis; and a manifold connecting the first container to the second container and having a longitudinal axis; wherein the longitudinal axis of the first container and the longitudinal axis of the second container each extend radially from the longitudinal axis of the manifold; and the longitudinal axis of the first container and the longitudinal axis of the second container intersect the longitudinal axis of the manifold at points that are axially displaced from one another along the longitudinal axis of the manifold.

2. The array of claim 1 , wherein each said container comprises a base end; a finish end; and a sidewall between the base end and the finish end; and each said container is connected to said manifold at the finish end.

3. The array of claim 1, wherein the first container and the second container are arranged side-by-side.

4. The array of clam 3, wherein the longitudinal axis of the first container is parallel to the longitudinal axis of the second container.

5. The array of claim 1 , wherein the longitudinal axis of the first container is perpendicular to the longitudinal axis of the manifold.

6. The array of claim 1, wherein the longitudinal axis of the first container and the longitudinal axis of the second container extend from the longitudinal axis of the manifold in opposite directions.

7. The array of claim 6, wherein the longitudinal axis of the first container extends at an angle that is 180° from the longitudinal axis of the second container.

8. The array of claim 1 , wherein the manifold comprises a blow hole.

9. The array of claim 1 , prepared by an extrusion blow molding process.

10. The array of claim 1 , prepared from a single parison.

11. An array of containers comprising: a manifold having a longitudinal axis; a first container connected to the manifold having a longitudinal axis, the longitudinal axis of the first container extending radially from the longitudinal axis of the manifold; and a second container connected to the manifold having a longitudinal axis, the longitudinal axis of the second container extending radially from the longitudinal axis of the manifold; wherein the longitudinal axis of the first container is non-collinear with the longitudinal axis of the second container.

12. The array of claim 11, wherein the first container and the second container are arranged side-by-side.

13. The array of claim 12, wherein the longitudinal axis of the first container is parallel to the longitudinal axis of the second container.

14. The array of claim 11, wherein the longitudinal axis of the first container is perpendicular to the longitudinal axis of the manifold.

15. The array of claim 11 , wherein the longitudinal axis of the first container and the longitudinal axis of the second container extend from the longitudinal axis of the manifold in opposite directions.

16. The array of claim 15, wherein the longitudinal axis of the first container extends at an angle that is 180° from the longitudinal axis of the second container.

17. The array of claim 11 , prepared by blow molding from a single parison.

18. A mold for blow molding containers comprising: a first mold cavity for blow molding a first container; a second mold cavity for blow molding a second container; a manifold cavity for blow molding a manifold, the manifold cavity being continuous with the first mold cavity and the second mold cavity; and a needle inlet positioned for blowing a gas into the manifold cavity, wherein a longitudinal axis of the first mold cavity is and non-parallel to a longitudinal axis of the manifold cavity, and a longitudinal axis of the second mold cavity is and non-parallel to the longitudinal axis of the manifold cavity.

19. The mold of claim 18, wherein the longitudinal axis of the first mold cavity, the longitudinal axis of the second mold cavity and the longitudinal axis of the manifold channel are substantially co-planar.

20. The mold of claim 18, wherein the longitudinal axis of the first mold cavity is perpendicular to the longitudinal axis of the manifold cavity.

21. The mold of claim 18, wherein a longitudinal axis of the manifold cavity is generally parallel to the direction along which a parison is extruded when the mold is used in a blow molding process.

22. The mold of claim 18, wherein a longitudinal axis of the first mold cavity is generally perpendicular to the direction along which a parison is extruded when the mold is used in a blow molding process.

23. A method for blow molding, comprising: providing two mold halves that, when closed, define a first mold cavity for blow molding a first container; a second mold cavity for blow molding a second container; a manifold cavity for blow molding a manifold, the manifold cavity being continuous with the first mold cavity and the second mold cavity; and a needle inlet positioned for blowing a gas into the manifold cavity, wherein a longitudinal axis of the first mold cavity is co-planar and non-parallel to a longitudinal axis of the manifold cavity, and a longitudinal axis of the second mold cavity is co-planar and non-parallel to the longitudinal axis of the manifold cavity; extruding a parison between the two mold halves in a direction generally parallel to the longitudinal axis of the manifold cavity; closing the mold halves; inserting a blow needle through the needle inlet to pierce the parison; and blowing air though the blow needle; thereby substantially simultaneously forming the first container and the second container.

24. The method of claim 23, further comprising opening the mold halves; and removing the first and second containers from the mold, thereby providing a container array.

25. The method of claim 24, further comprising separating a container from the container array.

26. The method of claim 25, further comprising trimming excess plastic from the container.

27. A container array prepared according to the method of claim 26.

28. The method of claim 23, wherein the longitudinal axis of the first mold cavity and the longitudinal axis of the second mold cavity are generally perpendicular to the direction in which the parison is extruded.

29. The method of claim 23 wherein extruding a parison consists of extruding a single parison.

30. The method of claim 23, wherein inserting a blow needle consists of inserting a single blow needle.

31. A container array prepared according to the method of claim 24.