Abstract:
In a single-row and expandable into a multi-row stretch blow molding method and apparatus, at least one row of tray plates in a tray unit is used to collect molded preforms ejected from the opening clamp of a preform-molding unit, transfer the preforms with or without transfer beads out of the molding area and align them with the center row distances of the downstream processing units. At least one robot having a universal gripper assembly is used to pick up either all or consecutively fractions of the preforms align them to the center distances of the blow mold cavities to place them at variable time intervals into a conditioning, stretch blow molding and oriented discharge unit, releases finished hollow articles and returns to a waiting position at the preform-molding and tray unit again at the preform mold&#39;s center distance independent of the preform-molding cycle. Simultaneously, component transfer devices may pick up external components, i.e. labels, valves or handles during the stretch blow molding phase and release the components into the blow-mold cavities while the universal gripper assembly is in the waiting position. The universal gripper assembly can alternatively also be pivoted to pick up preforms from a lateral reheat unit to supplement the molded preform supply. A modular stack-blow-mold clamp assembly is equipped with at least one row of blow mold cavities and with a plurality of pivoting spacing platens which in conjunction with helical spindles and nuts open and close the blow-mold halves and align their respective parting lines to correspond with the center-row distances of the transfer tray plates, conditioning and stretch blow means. Prior to the transfer of the molded preforms to a conditioning unit, internal components, i.e. sleeves or liners can be inserted into the neck and body portion of the preforms. Further, a secondary robot with a gripper assembly can pick up pretreated preforms from the first set of blow molds and transfer them into one or several consecutive blow mold assemblies all to obtain heat stable hollow articles or improved hollow article barrier performance prior to discharging.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a method for the preparation of preforms and hollow articles in single-row and multi-row preform and blow molds, respectively, and to an apparatus therefor. The invention represents an improvement in applicant&#39;s prior U.S. Pat. No. 6,217,819 entitled Universal Single Row and Multi Row Insert Stretch Blow Molding Method and Apparatus Therefor. More particularly, the present invention relates to a method and apparatus, wherein during a preform mold opening stroke an entering tray unit collects and removes molten preforms from the molding area. This end is attained by means of a robotic gripper assembly which lifts the preforms either out of the tray unit or from a preform reheat unit, transfers the preforms through different processing phases, adding internal and external components during the transformation into hollow articles, and returns to a waiting position outside the preform molding and tray unit or preform reheat unit. 
     2. Brief Description of the Prior Art 
     Heretofore, in conventional prior art molding machines, known as the one-step method, preforms, also called parisons, are injected into a preform mold and transferred by their neck splits which are mounted beneath a horizontal transfer plate in an intermittent rotary motion into a temperature control station, also called conditioning station, an orientation blow molding or stretch blow molding station and a molded product removing or ejection station producing hollow articles in single and double row molds, respectively., as described in U.S. Pat. Nos. 4,946,367, 4,731,011 both to Nissei ASB and Pat. No. 4,457,689 to Aoki respectively. The advantage of this method is that the preforms being held in an upright position can be precisely heat profiled internally with entering touch or conditioning rods. The drawback of this method is that the molten preforms are required to reside in the conditioning station as long it takes to inject and cool the preforms in the preceeding injection station. Heat pots emanating radiant heat are needed to maintain the proper stretch blow temperature, which adversely effects the programmed temperature profiling by the touch or conditioning rods. A technique for overcoming such limitations is described in U.S. Pat. No. 4,941,816 to Aoki U.S. Pat. Nos. 5,062,787 and 5,364,585 both to Aoki Technical Laboratory and U.S. Pat. No. 5,403,177 to Jomar wherein the injected preforms are directly heat conditioned in the preform mold and then immediately transferred into the stretch blow mold. The drawback of this method is that the preform molds are tailored to a specific hollow article geometry. This reduces the number of different hollow article shapes that can be stretch blown from the same preform shape. Unfortunately, such machines also evidence certain limitations, namely in the difficulty of mold interchangeability due to different swing radii and stack heights, the lack of built in automatic oriented discharge and costly neck splits and neck split holders which are required for each station. The vertical clamping forces applied to the neck splits in the preform molds versus the horizontal clamping forces in the blow molds being mounted onto a common rotary plate causes premature wear and tear to the aligning neck split seats. The rotary plates and the machine beds are required to be laid out for the higher clamping forces in the injection station. As a result, the added inertia of the heavy construction and large swing radii of the transfer plates lengthens the dead time of mold open index and mold close, thereby increasing the overall cycle times. Efforts to reduce dry cycle times have been made, as for example, by replacing the rotary tables through closed circuit conveying devices as described in U.S. Pat. No. 4,895,509 To Giacobbe-Magic and U.S. Pat. No. 5,213,822 to Nissei ASB. However, once again, costly support jaws or neck mold sets mounted on slide guides, are required for each station linked together to transfer the preforms and containers through the forming phases in a rectilinear motion in equal distances and equal time intervals. In the rotary-type and chain-link-type method, all phases of preform molding, conditioning, stretch blowing, and discharging are also interdependent due to a common transfer movement. The larger the number and size of transfer components, especially expensive neck splits, for each processing station leads to longer mold changeover times and higher tooling costs. The more machine component weight needs to be transferred, so resulting in slower dry cycles, and thus longer overall cycles. 
     The industry has recognized these limitations and has also recognized that containers can be conditioned, stretch blown, and discharged in a fraction of the time that it takes to mold the preforms. This discovery has led to a method and apparatus for injection stretch blow molding as described in U.S. Pat. No. 5,468,443 to Nissei ASB wherein a larger number of injection molding stations produce preforms to be conveyed to a lesser number of stretch blow molding stations. The drawback of this method and apparatus is that it requires neck split moving means for supporting and conveying costly neck splits adapted to hold-neck portions of each preform used to mold the hollow articles through all preform molding, conditioning, blow molding, and ejection stations. 
     Refinements of the aforementioned patent, U.S. Pat. No. 5,468,443 to Nissei ASB are described in U.S. Pat. No. 4,793,960 to Husky, U.S. Pat. Nos. 5,753,279, 5,744,176 and 6,247,916 all to Nissei ASB as well as brochures of Gerosa&#39;s Satellite GE system, SIG&#39;s Ecomax injection stretch blow molding machine and HUSKY&#39;s Index SB system are also known as one and a half step methods wherein molded preforms are first inverted to be released onto carrier members of a circular transfer conveying system. The inverted preforms are then indexed through a reheating section to assure that the first fraction of molded preforms enters the blow mold station with the same temperature profile as the following fractions of simultaneously molded preforms. Once the preforms are stretch blown into final hollow articles, they are inverted again to release them in an upright position. The limitations of these disclosures resides in the fact that the molten preforms are being inverted to be put onto a multitude of neck-size-dependent carrier members. During the inverting process the outside walls of the preforms touch water cooled transfer tubes in an uncontrolled manner, which tends to alter their thermal profile, so leading to uneven wall distributions in the finished hollow articles. The carrier members create a heatsink below the neck areas and, therefore, the reverted preforms need to be excessively heated in the shoulder area, which with long preforms may lead to bending during the intermittent transfer movements. The residence time of each fraction of preforms before entering the reheat oven banks is longer than each following fraction while the residence time in the reheat oven banks is the same for each preform fraction which enters the blow molds consecutively. The bottom up stretch blow molding method reverses the temperature profile of the preforms in the longitudinal direction. The bottom area of the preforms is hotter due to the chimney effect, which leads to preform-sagging and thinner bottoms and heavier shoulders in the hollow articles. Energy consuming cooling fans are installed to overcome this drawback. Preferential heating zones radiate onto the already hot preform outside walls for the production of oval hollow articles. This heat treatment of vertical section of the body of the preform is practiced successfully in so called two-step or reheat stretch blow molding processes because the preforms enter the heating sections at room temperature closely spaced and allow long oven residence times, as disclosed in U.S. Pat. No. 5,681,521 to Sidel and U.S. Pat. No. 6,287,507 to Corpoplast. A second inverting device is needed to release the finished hollow articles in an upright position. The number of injection cavities vs. blow cavities being mechanically coupled remains at a fixed ratio which limits the processing flexibility for instance for lighter-wall vs. heavier-wall containers. A further stretch blow molding concept is described in U.S. Pat. Nos. 4,372,910 and 4,470,796 both to Van Dorn in which molded preforms are picked up by two-row multiple gripper transfer devices, then inserted one row at a time into neck-size dependent collars of the respective closed circuit transportation system to be subsequently indexed to the conditioning, stretch blow and ejection stations. The drawback of this system is that the preforms need to be inserted into a large number of neck-size dependent collars of a transportation system consisting of a common closed loop belt drive which does not allow any timing flexibility between the simultaneous conditioning and stretch blow phases and precludes physical internal heat profiling with touch rods to obtain maximum processing flexibility. As described in European Patent. No. EP 0,768,166B1 to Sipa the thermal conditioning system is required to be twice as long as the stretch blow system to ascertain uniform temperature profiles for the first and second row preforms being introduced. U.S. Pat. No. 4,197,073 to Husky teaches a method, wherein alternate sets of parisons are released into laterally diverging tracks before arriving at the blow-molding unit. Despite the reduction in the number of blow mold cavities, in the end, the number of blowing means is equal to the number of preform mold means. U.S. Pat. No. 4,209,290 to Husky discloses a method wherein blow molding cells are interposed between open injection mold halves and injection cores with their preforms descending into the blow molding cells to form finished bottles. The limitation of this method is that the preform-molding cycle is interrupted during the time it takes to blow-mold the bottles. U.S. Pat. No. 4,310,282 to Emhart-Spurr uses a neck ring carrier to remove the parisons as a group to substitute this transfer with an assembly for the removal by the neck ring carriers which form a portion of the molded parison and a lateral transfer mechanism for positioning the parisons for delivery to the shuttle for final delivery to the blow station. U.S. Pat. No. 4,370,121 to Valyi discloses a multiplicity of tempering molds in spaced relationship to each other for retaining and tempering parisons prior to orientation and blowing. A well suited process for high output production of oriented hollow articles called the two-step method is disclosed in U.S. Pat. No. 6,152,723 to Krones, U.S. Pat. No. 5,863,571 to Sidel and U.S. Pat. No. 4,479,772 to Corpoplast whereby preforms are injection molded, cooled and stored in one location and then transported to a second location where they are unscrambled to be introduced into a reheat stretch blow molding machine. However at equivalent output rates the invention of a single and multi-row one and a half step stretch blow molding method and apparatus based on injection molding technology incorporating quick mold change means (not shown) presents numerous advantages over the two-step method in energy savings, mold change over times, transportation and double handling costs of preforms, less overall floor space requirements and less manpower. In integrated aseptic injection/stretch blow and filling lines the principal advantage over the two-step method is the elimination of chemical sterilants because both the molten preforms and hollow articles are kept sterile when they enter the aseptic filling system. This yields immediate savings in raw material costs and eliminates costly sterilizing/rinsing systems from the line. It prevents the taste of the hollow article contents being altered by residues of sterilants. 
     U.S. Pat. No. 5,731,014 to Tradesco, U.S. Pat. No. 4,718,845 to Sheffield, and U.S. Pat. No. 4,706,924 to de Larosiere disclose a solution for gaining maximum utilization of molding machines by simply switching mold cavities instead of complete molds in both stack molds and single-face mold versions clamped between a fixed and movable machine platen. This solution works well in conventional injection molding machines. However, in stretch blow molding machines, secondary components such as conditioning rods, blow cores, stretch rods, and bottom plugs, etc. need to be introduced at a predetermined center distance row. European Patent No. EP 0,768,165-A2 to Sipa teaches a method wherein mutually coupled mold plates, connected to a power transmission means, actuate through motion transferring means a double pair of mold halves. U.S. Pat. No. 4,941,816 to Aoki describes a double row clamp molding machine, wherein each blow mold row is closed by lateral pneumatic moving means. Subsequently, pancake cylinders rise between the two rows and expand to apply the necessary clamp pressure against oppositely located clamping means. Both methods are limited to a fixed number of two rows of blow molds at a fixed machine-dependent center row distance. U.S. Pat. No. 6,089,852 to Tradesco discloses a centering arrangement for controlling relative movement between a series of mold support plates in a multi-level stack mold having first and last mold support plates attachable respectively to a fixed and a moveable platen of an injection molding machine and at least two intermediate mold support plates interspersed sequentially therebetween. 
     U.S. Pat. No. 5,653,934 to Electra Form-Brun discloses a method for removing molded articles from a molding machine whereby article engaging elements comprising a plurality of pairs of elongated bars are placed into channels of the mold body as integral parts of the mold cavities to pick up molded preforms as soon as the mold opens, thereby eliminating the entering stroke for the removal grippers. The drawback of this method is that the available mold width is reduced by the channel spacings needed for the gripper means to enter during the molding phase. U.S. Pat. No. 6,129,883 to Husky discloses a vertical clamp index machine wherein molten preforms are ejected onto a conveyor into receiving means comprising cooled carriers. U.S. Pat. No. 5,273,152 to Electra Form and U.S. Pat. No. 3,753,589 to Holstein &amp; Kappert disclose apparatuses and grippers for altering the center spacing of the article in two directions simultaneously from the first center spacing of the downstream workstation to the second center spacing of the upstream workstation through plate means having a plurality of angled grooves, and a plurality of support members mounted slidably on the plate means. U.S. Pat. No. 4,323,341 to Valyi discloses means for varying the center spacing of the parisons to optimize the parison temperature for orientation and blowing by changing the center spacing of the parison mold and pick up of the parisons with a second set of cores having a center spacing of the blow molds. 
     U.S. Pat. Nos. 5,362,437 and 5,169,654 both to Nissei ASB disclose a method and apparatus whereby two rows of preforms are conveyed to a blow molding stage by changing the row pitch between the supporting plates when the blowing molds are opened and when the blowing molds are closed for the purpose of reducing the blow molding system in size and occupying area. 
     U.S. Pat. No. 5,683,729 to Sidel, U.S. Pat. No. 5,110,282 to Nissei ASB, U.S. Pat. No. 4,824,359 to Hoover Universal, and 4,403,907 to Emerson Electric disclose cam-driven rotary pick and place assemblies, which simultaneously carry preforms and hollow articles through the blow molding and release phases. The limitation of such carrying means is that their rotary motion is interdependent, requires space modifying devices and, therefore, does not allow any timing and stroke distance flexibility between the various processing phases. A method for adding external components such as labels, handles, or valves to the preforms or hollow articles is described in U.S. Pat. Nos. 4,479,771 and 4,721,451 both to Plastipak, wherein components, such as labels, are picked up from dispensing heads by the label carrier shuttle and are moved rectilinearly into an open mold wherein they are released onto the mold cavity walls and returned in the same manner to the dispensing head position. The drawback of this method is that the normal blow molding cycle of rotary machines is interrupted to allow the time to introduce the labels into the open mold cavities. Typically, finished containers have to be evacuated first and new preforms need to be delayed from entering the open mold cavities. U.S. Pat. No. 4,983,348 to Wheaton partially overcomes this limitation by opening the upper mold half earlier and inserting labels into the open mold half while holding the previously blown and labeled work pieces or hollow articles in the lower mold half for the duration of the label transfer phase without increasing the overall machine cycle time. The drawback of this method is that only one mold half can receive labels and the distance between the work piece and movable blow mold halves needs to be sufficient to allow the dispensing mechanism to operate in between. 
     To add secondary components to preforms or hollow articles, U.S. Pat. No. 5,678,771 to Graham Packaging teaches a method wherein an insert is attached on the surface above the threads of a neck finish to maintain stability during and after hot-fill processing. The drawback of this method is that the non-oriented, amorphous neck finish portion beneath the attached reinforced insert can shrink and deform during the hot-fill phase. U.S. Pat. No. 4,988,472 to Nissei ASB teaches a method that prevents the aforementioned-mentioned drawback. However, the insert is placed into a neckring portion of an open mold first and then over-molded with molten material, an operation that lengthens the overall cycle. 
     U.S. Pat. No. 4,847,129 to Continental PET teaches a method of molding a multi-layer neck-finish structure whereby the center layer consists of a high temperature polymer. 
     U.S. Pat. No. 5,651,933 to Plastipak and U.S. Pat. No. 3,939,239 to Valyi teach a method wherein thermoformed sleeves are put on injection cores and are over molded to obtain a multi-layer preform. The inner over molded layer needs to be stiff enough to withstand the following injection pressures when injecting the outer layer. Thus, this method requires more costly inner barrier material and is more difficult to bond with the over molded material. 
     U.S. Pat. No. 5,516,274 to Electra Form describes a movable blow mold clamp assembly permitting improved access for servicing. 
     SUMMARY OF THE INVENTION 
     1. Purposes of the Invention 
     It is an object of the present invention to mold preforms in single-row or multi-row preform mold cavities in variable-row spacings to give the molder maximum flexibility in meeting small and large production output requirements. Preform molds can be mounted perpendicular or in line relative to one or several plasticizers. 
     It is a further object of the invention to enter a tray unit with at least one row of tray plates in between the opening preform mold to collect ejected preforms from above mold halves into their corresponding openings and immediately retract away from the preform molding area. 
     It is a further object of the invention to hold ejected preforms from above mold halves in corresponding openings of the non heat conducting tray plates with their respective transfer rings. 
     It is a further object of the invention to hold ejected preforms without transfer rings from above mold halves with their bottom gate sections in non heat conducting catch baskets mounted beneath the tray plate openings 
     It is a further object of the invention to enter a tray unit with a corresponding number of tray rows than preform mold rows in between the opening preform mold to collect ejected preforms from above mold halves into their corresponding openings and immediately retract away from the preform molding area. 
     It is a further object of the invention to enter a tray unit with a corresponding number of tray rows than preform mold rows in between the opening preform mold to collect ejected preforms from above mold halves into their corresponding openings and immediately retract away from the preform molding area into the conditioning unit. 
     It is a further object of the invention to retract the multitude of tray rows away from the molding area in a telescoping manner to align the multitude of tray plate rows with the center row distances of the downstream units. 
     It is a further object of the invention to transfer the preforms from the tray unit to the downstream units in an upright position. 
     It is a further object of the invention to utilize a robot with a universal gripper assembly which picks up molded preforms from the retracted tray unit and transfers the same across a conditioning unit into a stretch blow unit to be converted into hollow articles, and then transfers them onto an oriented discharge unit at variable time and stroke intervals before returning to a waiting position at the preform molding unit and the tray unit. 
     It is a further object of the invention to freely move the robot with the universal gripper assemblies in horizontal and vertical directions to position the preforms into the different processing units to condition, stretch blow and discharge the same. 
     It is a further object of the invention to lay out the grippers at a multitude of center distances to enable the transfer of preforms and hollow articles with different size neck finishes and at various mold cavity center distances. 
     It is a further object of the invention for a universal gripper assembly to pick up the molten preforms from the tray unit at the center distance spacings of the preform mold and to telescope the molten preforms into center distance spacings corresponding to the center distance spacings of the blow mold cavity center distances 
     It is a further object of the invention to utilize a robot with a universal gripper assembly which picks up fractions of molded preforms consecutively from the retracted tray unit and transfers the same across a conditioning unit and into a stretch blow unit to be converted into hollow articles, and then transfers them onto an oriented discharge unit at variable time and stroke intervals before returning to a waiting position at the preform molding and tray unit. 
     It is a further object of the invention to condition each fraction of preforms consecutively, internally by rows of touch rods, externally by rows of heat pots. It is a further object of the invention whereby a primary robot with a universal gripper assembly picks up a fraction of conditioned performs, transfers the same into at least one row of a stretch blow unit and returns to the conditioning unit to pick up a subsequent fraction of conditioned performs from the tray unit and whereby a secondary robot with a universal gripper assembly picks up hollow articles from at least one row of the stretch blow unit and transfers them onto an oriented discharge unit. 
     It is a further object of the invention whereby a robot with a universal gripper assembly picks up fractions of conditioned molten preforms from a tray unit transfers them into a stretch blow molding unit and discharge unit which returns to the tray unit to pick up a subsequent fraction of conditioned molten preform to be transferred into the downstream units and eventually returns to a waiting position at the preform molding and tray unit. 
     It is a further object of the invention whereby a multitude of robots with universal gripper assemblies pick up fractions of conditioned molten preforms from a common tray unit, transfer them into a multitude of stretch blow molding and discharge units and return to their respective waiting positions at the preform molding and tray unit. 
     It is a further object of the invention to maximize the production capabilities through stack blow molds, wherein the blow mold opening and closing strokes are accelerated by the clamp moving means together with a multitude of helical spindles with helical nuts mounted onto the diverging and converging blow mold clamp platens and pivoting spacing platens aligning the center row distances of the corresponding stretch rod, blow core, and bottom plug assemblies. The number of spacing-platen rows can be increased or decreased according to the desired number of blow mold rows. 
     It is a further object of the invention to vary the number of center row distances in the conditioning, stretch blow, and bottom plug units according to the number of center rows of the preform molds. 
     It is yet a further object of the invention to turn the conditioning and stretch blow mold units to match the number of perform mold rows. 
     It is yet a further object of the invention to reduce the number of blow mold cavities to a fraction of the number of perform mold cavities. 
     It is a further object of the invention to collect at least two rows of molten preforms in the openings of the tray plates of the tray unit at the center row distance of the preform mold cavities and telescope the molten preforms into the center row distances of the blow mold cavities during the retracting movement of the tray unit out of the molding area. It is a further object of the invention to add additional blow mold units for multi-stage stretch blow mold applications. 
     It is a further object of the invention to add a secondary robot with a secondary universal gripper assembly to transfer pretreated hollow articles from the first blow mold unit into subsequent blow mold and discharge units. 
     It is a further object of the invention to add component transfer devices to pick up components during the blow-molding phase and to introduce these components into the open blow molds during the waiting phase. 
     It is a further object of the invention to insert components on the neck inside of preforms before the shrinkage phase of the molten material has been completed. 
     It is a further object of the invention to insert components on the inside of the preform walls prior to the conditioning and stretch blow-molding phase. 
     It is a further object of the invention to pivot the gripper assembly to pick-up reheated preforms from a lateral reheat oven assembly. 
     It is a further object of the invention to mount the upper conditioning and blow-clamp assemblies onto linear bearings, so enabling the movement of said clamp assemblies laterally to facilitate mold and machine component mounting. 
     2. Brief Description of the Invention 
     In accordance with the present invention, molten material is introduced into single-row or multi-row preform mold cavities. Upon completion of the solidification phase, the upper mold half is raised together with the injection cores. Immediately thereafter, during the mold-opening stroke, a tray unit with at least one row of tray plates enters between the movable mold halves collects the molten preforms through corresponding openings in the tray plates and retracts immediately out of the molding area. The preforms are either held onto the tray plates by their transfer beads or in the absence of such transfer beads by their bottom gate sections in catch baskets mounted beneath the corresponding openings of the tray plates. A robot with a universal gripper assembly then lifts either all or consecutively a fraction of the preforms out of the retracted tray unit and transfers the preforms to the conditioning unit, while the preform mold is closed again to mold the next set of preforms. The robot with the universal gripper assembly holds the preforms in the conditioning unit just long enough for the internal touch rods and external heater pots to monitor the temperature profile in the preforms. Next, the robot with the universal gripper assembly brings the conditioned preforms into the blow molds, wherein, after the bottom plugs have been raised and the blow molds have been closed, the blow cores and stretch rods descend to enter the preforms at their open ends, low and high pressure blow air comes on and forms finished hollow articles. Immediately upon completion of the stretch blow cycle, the blow cores and stretch rods lift out of the blow molds, the blow molds are opened, and the robot with the universal gripper assembly lifts the finished hollow articles out of the blow mold cavities to transfer the same into the oriented discharge unit. The robot with the now empty universal gripper assembly returns to a waiting position at the preform molding and tray unit Due to the fast cooling nature of certain materials, such as PET or PEN, among others, the time periods necessary for conditioning, stretch blowing, cooling, and oriented discharging, as well as for the short and quick transfer strokes of the servo controlled robot with its light-weight universal gripper assembly and with its reduced inertia happen within a fraction it takes to mold the preforms. This benefit allows picking up the molten preforms with the universal gripper assembly in fractions as well and transferring the same through the downstream processing units having a lesser number of blow mold cavities than preform cavities. 
     In addition to the preform supply from the molding unit, outsourced preforms from an adjacent reheat unit can be supplemented. During this intermediate phase, the universal gripper assembly pivots and picks up reheated preforms from said reheat unit and transfers them the same way in a short linear movement through the conditioning, stretch blow, and oriented discharge phases. 
     In view of the freely programmable and time-independent movement of the robot with the universal gripper assembly, following component transfer devices can be added. During the stretch blow phase, these transfer devices pick up components such as labels, handles, valves, etc. When the robot with the universal gripper assembly has returned to the waiting position, the components are released into each blow mold half, all without any increase in the total cycle time. 
     The above described process shows that the number of blow mold cavities is either equal to or a fraction of the number of preform mold cavities. To further boost production and to gain maximum utilization of the preform-molding unit, stack-blow molds are installed to meet the production of a larger number of preform mold cavities. The blow-mold clamp requirements are virtually the same with single-row or multi-row blow mold assemblies. A selectable number of helical spindles with helical nuts and pivoting spacer platens, located between the blow mold rows, provide instant mold opening and closing as well as parting-line alignment with the entering bottom plugs, blow core and stretch-rod assemblies mounted in a stationary position. A synchronized movement of the enveloping tiebar mounted blow-mold clamp platens and generated by the closing means provides the final blow-mold clamping pressure. The helical spindles with helical nuts mounted onto the blow mold clamp platens accelerate the blow mold opening and closing strokes in conjunction with the pivoting spacing platens movements. The spacing platens being connected to the intermediary blow mold clamp platens follow and are reversed by the diverging and converging clamp movement at low friction. A central step motor and gear pulleys mounted beneath onto each spacing platen enveloped with a common drive belt amplifies the pivoting movement against mechanical stops (not shown) to ascertain perpendicularity positioning during the mold closing phase. The fully mechanical stack blow mold assembly with its synchronized clamp movements and mold height adjustments via tooth belted tie bar nuts and electrical drive is also well suited for heat set container production. The stretch blow assemblies located above the stack blow mold clamps are adjustable within the center row distances to align with the respective blow mold parting lines. 
     The injection cores, conditioning and stretch blow rods are held onto individual clamp bars. The clamp bars are bolted individually onto the machine clamp platens according to the center distance rows of the blow-mold cavities. The neck splits or stripper plates and the blow cores are also mounted on individual clamp bars. These clamp bars are bolted individually onto frame-type machine clamp platens within the respective units. This flexibility in varying the center row distances in the individual processing units or by telescoping the tray plates of the tray unit into the center row distances of the down stream units during the molten preform discharge stroke as well as telescoping the universal gripper means from the center distances of the preform molds to the center distances of the blow molds permits the mounting of existing molds from other stretch blow processes, or adding or deleting mold cavity rows, thereby increasing or decreasing mold opening daylights for the production of larger and smaller hollow articles, respectively. 
     The injection, conditioning, stretch blow and oriented discharge units can be turned based on the preform mold design to minimize the number of universal gripper assemblies. 
     Certain molten materials such as PC or PP, heavy-wall returnable PET bottles or heat-set PET bottles may require stepped processing treatments to achieve specifications. In this case, additional blow-mold units and a secondary robot with a universal gripper assembly are installed. In this processing mode, once the primary robot with the universal gripper assembly has transferred the preforms into the first blow-mold assembly, it returns to the waiting position at the preform-molding machine. A secondary robot with a universal gripper assembly picks up the pretreated preforms and transfers them directly to one or several subsequent blow mold units and finally to an oriented discharge unit. 
     Hollow articles tend to deform in non-stretch blow-molded areas such as the neck finishes during hot-fill operation. A unit capable of transferring internal components into preforms may be installed right after the preform-molding unit and above the tray unit. An internal component transfer device picks up heat-stable sleeves from a sorting conveyor and incorporates the same into the open-ended preforms at elevated neck temperatures, thus before the shrinkage phase has been completed. The robot with the universal gripper assembly picks up the sleeve-reinforced preforms and transfers them to a conditioning unit, wherein the cooling neck finishes shrink tightly onto the heat-stable sleeves. After passing through one or several stretch blow units, neck heat-stable hollow articles are released into an oriented discharge unit. 
     To enhance the barrier properties of hollow articles, a thin inner liner of high-barrier material can be inserted the same way into the preforms by the internal component transfer device prior to transferring the same into a conditioning and stretch blow unit. 
     The above-described stretch blow molding method and apparatus provides the molder with maximum production flexibility by forming hollow articles in either single-row or multi-row blow-mold assemblies as well as processing versatility in adding additional stretch blow mold units and introducing external and internal components to the hollow articles. The open architecture of the individual processing units permits the installation of molds from different machine designs and requires one set of neck splits in the preform mold only. The completely separate preform molding unit from all other processing units and preform pick-up from a tray unit allows quick mold opening and closing of the preform mold clamp. All the downstream phases described above happen within the preform-mold filling, forming, cooling and take out phases. Thus, the preform-molding phase and the rapid mold opening preform take-out by a tray unit and mold-closing phase constitutes the total processing cycle. 
     Adding an additional reheat unit further increases the output capabilities of the stretch blow-molding machine to meet seasonal market demands. 
     Prior art for robotic gripper assemblies requires removal of preforms from a molding unit or finished hollow articles from an ejection or blow-mold station of a stretch blow-molding machine when in a static position and placing them onto conveying means. The improvement described herein involves the use of a tray unit and a robot with a universal gripper assembly to pick up molded preforms in total or in fractions in an upright position from a tray unit which have been collected from a preform molding unit during the mold-opening stroke or from a reheat oven and transferring them at freely programmable intervals to a multitude of individual processing units performing multiple functions, such as conditioning, stretch blowing, adding internal or external components, or hand-over pre-treated hollow articles to subsequent stretch blow units prior to final release of the finished hollow articles. In this capacity, the tray unit and the robot with the universal gripper assembly replaces the use of heavy rotary transfer plates carrying neck splits for each station, or circulatory carriers with neck-mold moving pieces, or carriages with neck-size-dependent support jaws, each being linked together in a closed circuit. 
     Prior art for multi-row blow-mold clamps requires that each blow mold row be first closed by pneumatic external moving means. Subsequently, a pancake cylinder assembly is raised in between the rows which are expanded to apply the necessary clamp pressure against opposite clamping cylinders on each end, or a power transmission means is used to actuate, through motion-transferring means, a double pair of mold halves only. 
     In accordance with the present invention, a multitude of helical spindles with helical nuts and pivoting spacing platens are mounted to instantly create a mechanical blow mold row opening and closing action within selected center distance rows. Synchronized peripheral clamping means are used simultaneously to apply the necessary opening and closing force. A further refinement involves the flexibility of adding or deleting spacing platens depending on the desired number of blow-mold rows. The benefits to the molder are to adapt production outputs to market demands within the same stack-mold clamping means. The higher output rate capabilities of stack-blow-mold assemblies make in-line hollow article filling and pasteurization economical with the one-step and one and a half step process. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be more readily understood by reference to the following detailed description taken in conjunction with the accompanying drawing wherein: 
     FIG. 1 is a side view of a stretch blow molding apparatus showing from right to left a plasticizer, a preform molding unit with a tray unit, a conditioning unit, a robot with freely programmable universal gripper assembly in a waiting position, a component-transfer device assembly, a stretch blow mold unit, an oriented discharge unit beneath front and back component dispensing cartridges; 
     FIG. 2 is a front view of a stretch blow molding unit with clamp cylinders, a stretch rod assembly, a blow core assembly mounted on linear bearings, a robot with a universal gripper assembly and drive, a blow-mold clamp assembly with pivoting spacing platens and drive means as well as bottom plug moving means; 
     FIG. 3 is a back view of a stretch blow molding unit and component-dispensing assembly showing from top to bottom blow-clamp cylinders, component dispensing cartridges, a robot with the component-transfer device assembly in a component pick-up position, a universal gripper assembly holding the hollow articles in the blow-mold assembly, a pivoting spacing platen with drive means, and a bottom-plug moving means; 
     FIGS. 4-11 represent a schematic sequence of a robot with a universal gripper assembly, followed by a transfer component device assembly in conjunction with a tray unit and a stretch blow molding sequence; 
     FIG. 4 shows a schematic side view of a robot with a universal gripper assembly picking up a molded preform and a transfer component device assembly in a stand-by position; 
     FIG. 5 shows a schematic top view of a stretch blow molding sequence showing from right to left a plasticizer, a preform-molding unit, a tray unit, a conditioning unit, a stretch blow molding unit in a closed position with external components applied, and an oriented discharge unit; 
     FIG. 6 shows a schematic side view of a robot with a universal gripper assembly holding a hollow article with external components applied as well as a transfer component device assembly in an external component pick-up position; 
     FIG. 7 shows a schematic side view of a robot with a universal gripper assembly in a finished hollow article discharge position at a tray plate of a tray unit and a transfer component device assembly holding external components on a front and back side; 
     FIG. 8 is a schematic top view of a stretch blow molding sequence showing from right to left a plasticizer, a preform molding unit with a tray unit in a molten preform discharge position, a conditioning unit, a stretch blow molding unit in an open position ready to receive external components by a transfer component device assembly, a universal gripper assembly in a waiting position, and an oriented discharge unit; 
     FIG. 9 shows a schematic side view of a robot with a universal gripper assembly in a waiting position and a transfer component device assembly in an external component-release position; 
     FIG. 10 shows a schematic top view of a stretch blow molding sequence showing from right to left: a plasticizer, a preform molding unit with a tray unit in a preform discharge position, a conditioning unit, a stretch blow molding unit in an open position holding external components, such as labels in each mold half, a transfer component device assembly in a component-pick-up position and a universal gripper assembly in a stretch blow position, front and back component-dispensing cartridges, above an oriented discharge unit; 
     FIG. 11 shows a schematic side view of a robot with a universal gripper assembly ready to pick up a preform from a tray plate and a component transfer device assembly in an external component stand-by position; 
     FIG. 12 is a top view of a single-row stretch blow molding apparatus showing from right to left a plasticizer, a preform-molding unit with a tray unit, a conditioning unit, a stretch blow unit and stack blow mold clamp assembly with pivoting spacing platens, and an oriented discharge unit with a universal gripper assembly; 
     FIG. 13 is a top view of a single-row stretch blow mold apparatus, as shown in FIG. 12, in which the plasticizer, preform-molding unit with tray unit, conditioning unit, stretch blow unit, and oriented discharge unit have been turned to minimize the number of universal gripper assemblies mounted onto the robot; 
     FIG. 14 shows a schematic movement of a universal gripper assembly as from right to left starting at a take-out position of a preform molding unit at the tray plate of a tray unit, traversing to a conditioning unit, descending onto a stretch blow unit, retracting to an oriented discharge unit, returning to a waiting position, and ascending back to the tray unit at a preform molding unit; 
     FIG. 15 is a top view of a single-row stretch blow molding apparatus with a robot and a pivoting universal gripper assembly picking up preforms from a reheat unit and transferring the same through a conditioning and stretch blow unit into an oriented discharge unit; 
     FIG. 16 shows a schematic side view sequence of a robot with a universal gripper assembly in a pivoted position, picking up reheated preforms from a reheat unit, pivoting back to its basic position to bring them to a conditioning unit, releasing them into a stretch blow unit for transforming into hollow articles, retracting them toward an oriented discharge unit, and returning to a reheat unit or tray unit; 
     FIG. 17 is a side view of a single-row stretch blow molding apparatus showing from right to left a plasticizer, a preform molding unit with a tray unit in a retracted position, a robot with a universal gripper assembly in a pivoted position, a reheat unit behind, a conditioning unit, a stretch blow unit, and an oriented discharge unit; 
     FIG. 18 is a top view of a single-row stretch blow molding apparatus as shown in FIG. 12, wherein a robot together with the universal gripper assembly indexes along a lateral guide rail; 
     FIG. 19 is a top view of a multi-row stretch blow molding apparatus wherein a robot together with a universal gripper assembly indexes along a lateral guide rail; 
     FIG. 20 shows a back view of a schematic movement of a laterally indexing robot with a universal gripper assembly from right to left, starting at a take-out position of a tray unit in the preform-molding unit, ready to move into a conditioning unit from where the robot descends, onto a stretch blow unit, retracts to an oriented discharge unit, returns and ascends back into the conditioning unit waiting for the tray unit to supply molten preforms from the preform-molding unit; 
     FIG. 21 shows the top view of a one and a half step stretch blow molding assembly consisting of a plasticizer, a preform molding unit with a double row preform mold and a tray unit, a primary gantry robot with a universal gripper assembly, a single row stretch blow unit and a secondary gantry robot with a universal gripper assembly and a discharge unit beneath; 
     FIG. 22 shows the top view of a one-step stretch blow molding assembly consisting of a plasticizer, a preform molding unit with a multi-row tray unit, a conditioning unit, a primary gantry robot with a multi-row universal gripper assembly, a stack blow mold unit, a secondary gantry robot with a multi-row universal gripper assembly 
     FIG. 23 show the top view of a tray unit in a preform molding unit with tray plates telescoped into an extended row preform discharge position; 
     FIG. 24 shows the top view of a tray unit in a preform molding unit with tray plates in a retracted preform collecting position; 
     FIG. 25 shows the front view of a tray unit in a preform molding unit holding molten preforms in a tray plate by their transfer beads; 
     FIG. 26 shows the front view of a tray plate with catch baskets holding molten preforms without transfer beads; 
     FIG. 27 is a side view of a multi-row stretch blow molding apparatus showing from right to left a plasticizer, a preform-molding unit with a tray unit in a telescoped position holding preforms by their transfer beads, a conditioning unit, a stretch blow unit, an oriented discharge unit, and a robot with universal gripper assembly; 
     FIG. 28 is a side view of a multi-row stretch blow molding apparatus showing from right to left a plasticizer, a preform-molding unit with a tray unit and catch baskets in a telescoped position holding preforms without transfer beads, a conditioning unit, a stretch blow unit, an oriented discharge unit, and a robot with universal gripper assembly; 
     FIG. 29 is a top view of a multi-row stretch blow molding apparatus showing from right to left a plasticizer, a preform molding unit with a preform mold assembly and a tray unit with tray plates in a telescoped preform discharge position, a conditioning rod-holding platen and rows of conditioning rod-holding bars mounted beneath (not shown), a stretch-rod holding platen, and rows of blow-core holding bars mounted onto a frame-type clamp platen beneath, an oriented discharge unit beneath a robot with a universal gripper assembly, and a drive mounted onto a traversing beam rail frame of the robot; 
     FIG. 30 shows the top view of a robot with a telescoping universal gripper assembly in a retracted preform pick up position; 
     FIG. 31 shows the top view of a robot with a telescoping universal gripper assembly in an extended preform placing position; 
     FIG. 32 shows the front view of a robot with a telescoping universal gripper assembly, holding a preform; 
     FIG. 33 shows the top view of a one and a half step stretch blow molding assembly with a plasticizer, a preform molding unit with a two row preform mold and two row tray unit above a conditioning unit, a single row blow mold unit and a gantry robot with a universal gripper assembly at a discharge unit; 
     FIG. 34 shows the top view of a multi row one and a half step stretch blow molding assembly with two plasticizers, a preform molding unit with a multi row preform mold and a multi row tray unit, a conditioning unit beneath, a stack blow mold unit, a gantry robot with-a telescoping universal gripper assembly and an oriented discharge unit beneath; 
     FIG. 35 shows the top view of a multi row one and a half step stretch blow molding assembly with two plasticizers, a preform molding unit with a multi row preform mold and a multi row tray unit, a conditioning unit, a stack blow mold unit, a gantry robot with a telescoping universal gripper assembly and an oriented discharge unit beneath; 
     FIG. 36 shows a schematic movement of a universal gripper assembly from right to left at a fractional pick up position of molten preforms from a tray unit, traversing a conditioning unit, descending onto a stretch blow unit, retracting to an oriented discharge unit, returning to the tray unit to pick up a subsequent fraction of molten preforms (not shown); 
     FIG. 37 shows the top view of a multi row one and a half step stretch blow molding assembly with two plasticizers, a preform molding unit with a multi row preform mold and a multi row tray unit, a conditioning unit beneath, a multitude of stack blow mold units, a multitude of gantry robots with telescoping universal gripper assemblies and oriented discharge units beneath; 
     FIG. 38 is a top view of a stack-blow mold assembly section in a closed position with the spacing platen assembly in an extended position; 
     FIG. 39 is a top view of a stack blow mold assembly section in an open position with the spacing platens assembly in a retracted position showing the rows of bottom plugs, a clamp moving means, and a clamp-platens synchronizing gear mechanism; 
     FIG. 40 is the side view of a stack blow mold assembly in a closed position; 
     FIG. 41 is the side view of a stack blow mold assembly in an open position; 
     FIG. 42 is a sequential view from right to left of a molded preform with internal component preparation, an internal component pick-up and inserting device, a molded preform with an inserted internal component and a finished hollow article with an inserted internal component; 
     FIG. 42 a  is a sequential view from right to left of a molded preform as shown in FIG. 42 wherein an inner liner has been inserted into the preform and a multi-layer hollow article has been formed; 
     FIG. 43 is a side view of a multi-row stretch blow molding apparatus as described in principal in FIG. 27 showing from right to left a plasticizer, a preform molding unit with a tray unit holding molten preforms with their transfer beads on telescoped tray plates, an internal component indexing sorting and conveying unit and an internal component pick-up and inserting unit, a conditioning unit, a stretch blow unit, an oriented discharge unit, and a robot with a universal gripper assembly; 
     FIG. 44 shows a side view of a multi-row stretch blow molding apparatus as described in principle in FIG. 28 from right to left a plasticizer, a preform molding unit with a multi-row tray unit including catch baskets holding molten preforms without transfer beads, an internal component-indexing sorting and conveying unit, a conditioning unit, a stretch blow molding unit, a robot with universal gripper assembly, a secondary robot with a secondary universal gripper assembly above an oriented discharge unit; 
     FIG. 45 shows a top view of a multi-row stretch blow molding apparatus a shown in principal in FIG. 35 from right to left the plasticizers, a preform molding unit with a multi-row tray unit, an internal component-indexing sorting conveyor unit, a conditioning unit, a primary stretch blow molding unit, a primary gantry robot with a universal gripper assembly, a secondary stretch blow molding unit, a secondary gantry robot with a secondary universal gripper assembly above an oriented discharge unit; 
     FIG. 46 shows a schematic side view sequence of a primary and a secondary robot with universal gripper assemblies from right to left the primary robot with the universal gripper assembly picks up a fraction of preforms (not shown) from a tray unit, indexes to an adjacent internal component-indexing sorting and conveying unit, travels to a conditioning unit, releases the preforms into a primary stretch blow molding unit, returns to a waiting position, and at the tray unit to pick up another fraction of molten preforms. In the meantime, a secondary robot with a universal gripper assembly picks up the pretreated preforms (not shown) and transfers the same into a secondary stretch blow molding unit and oriented discharge unit. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In accordance with the present invention there is provided a single-row and multi-row stretch blow molding method and apparatus, wherein a tray unit with at least one row of tray plates collects molten preforms from a preform-molding unit during the mold-opening stroke and guides them out of the molding area. A robot with a universal gripper assembly picks up the molten preforms in an upright position and guides them through the steps of conditioning, stretch blow molding, oriented discharging, and then returns to a waiting position at the preform-molding unit and tray unit. The freely programmable time and stroke intervals of the robot with the universal gripper assembly to complete the stretch blow molding process are substantially faster than the preform molding process and thus allows the pick-up of fractions of preforms sequentially or additional preforms from a reheat unit and the introduction of components to the external and internal walls of the hollow articles without increasing the overall cycle. A modular stack-blow-mold assembly provides the opportunity for increased production in the same blow molding apparatus. A secondary set of robots with universal gripper assemblies and blow mold units provide the opportunity to treat the preforms in multi-stages before being released as hollow articles into an oriented discharge unit or further increase the output rates of the stretch blow molding system. 
     With reference now more particularly to the drawings, FIG. 1 is a side view of a stretch blow molding method and apparatus, showing from right to left a plasticizer  10 , a preform-molding unit  12  with a preform-mold-cavity assembly  26  in a closed position mounted on a base frame  20 , wherein the neck splits  18  remain in sliding connection  87  with the preform-mold-cavity assembly  26  upon raising the frame-type platen  16  holding the ejector bar  88  by the vertical clamp cylinders  14  and  15 . Tie bars  19  connect the base platen  20  with the upper clamp platen  13 . A movable intermediary clamp-platen housing  21  is connected to the frame-type clamp platen  16 . A central clamp cylinder  22  is mounted onto the intermediary clamp-platen housing  21 , which moves the injection core-holding platen  23  with the injection-core-mounting bar  24  and injection cores  25 . During the opening movement of the frame-type clamp platen  16 , a tray unit  115  with at least one row of tray plates  116  through the tray unit moving means  119  starts entering the opening clamp area. As the central clamp cylinder  22  moves the injection cores  25  upwards beyond the ejector bar  88 , the tray unit  115  collects the freeing molded preforms  89  in the openings  120  of the tray plate  116  and transfers them to a conditioning unit  31 . A universal gripper assembly  27 , mounted onto a robot  28  picks up the conditioned preforms  89  and guides them from there into a stretch blow-molding unit  40  to form the hollow articles  86  which are subsequently released in an oriented discharge unit  58 , and returns to a waiting position  81  at the tray unit  115 . 
     A following transfer component device assembly  90 , which has picked up external components  92  from front and back component dispensing cartridges  91  during a previous stretch blow molding phase, places the same external components  92  into the open blow molds  41  in its component release position  94  during the waiting phase of the universal gripper assembly  27 . 
     FIG. 2 shows a front view of a stretch blow molding unit  40 , wherein the upper portion  60  with the upper moving-means platen  51  on which are mounted the vertical stretch blow moving means  50  and  75  that drive the blow cores  47  which are mounted on a frame-type platen  49  with blow-core holding bars  48  and intermediary stretch-rod clamp-platen housing  52  having central stretch-rod moving means  57  mounted onto the frame-type blow-core clamp platen  49  holding the stretch rods  56 , which are mounted on a stretch-rod holding platen  54  with stretch-rod holding bars  55  which ride on linear bearings  59  enabling the upper portion to slide out of its operating position to facilitate the mold change-over procedure. A track rail  30  guides a traversing beam  61 , which is monitored by a drive  62 . Traversing beam  61  carries robot  28  with the vertical gripper moving means  29  and the gripper opening and closing means  63  of the universal gripper assembly  27 . A stack-blow mold assembly  41  is located beneath the upper portion  60  of the stretch blow unit  40  mounted between blow mold clamp platens  67  attached to tie bars  66 . Pivoting spacing platens  44  monitored by rotating means  45  and drive gears  64  are mounted in between the blow mold-cavity assembly  41 , onto a support frame  65  and upper center cross bars  70 . Moving means  43  mounted onto a support frame  65  monitors&#39; bottom-plug rows  42 . 
     FIG. 3 is a back view of a stretch blow mold unit  40  as described in FIG. 2. A frame assembly  93  in front of the stretch blow unit  40  holds the front and back component dispensing cartridges  91 . A following transfer component device assembly  90 , mounted on a traversing beam  61 , is in its component pick-up position  95  while the universal gripper assembly  27 , the blow cores  47 , and stretch rods  56  are in a stretch blow molding position  97 . 
     FIGS. 4 to  11  show a schematic sequence of a robot  28  with a universal gripper assembly  27  followed by a transfer component device assembly  90  in conjunction with a tray unit  115  and a stretch blow molding sequence. 
     FIG. 4 shows a schematic side view of a robot  28  with a universal gripper assembly  27  picking up a molded preform  89  and a transfer component device assembly  90  in a stand-by position  98 . 
     FIG. 5 is a schematic top view of a stretch blow molding sequence showing from right to left a plasticizer  10 , a preform molding unit  12 , a tray unit  115  with a tray plate  116  and openings  120 , a conditioning unit  31 , a stretch blow molding unit  40 , a robot with a universal gripper assembly (not shown), wherein external components  92  are being applied in the closed stretch blow-mold assembly  83  onto finished hollow articles  86  and a finished hollow article discharge unit  58 . 
     FIG. 6 shows a schematic side view of a robot  28  with a universal gripper assembly  27  in a hollow article stretch blow molding position  97  and a finished hollow article  86  with external components  92  applied as well as a transfer component device assembly  90  in an external component pick-up position  95 . 
     FIG. 7 shows a schematic side view of a robot  28  with a universal gripper assembly  27  in a finished hollow article discharge position  80  at a tray plate  116  with opening  120  and a transfer component device assembly  90  in a stand-by position  98  holding external components  92  on the front and back side. 
     FIG. 8 is a schematic top view of a stretch blow molding sequence showing from right to left a plasticizer  10 , a preform molding unit  12  with a tray unit  115 , tray plate moving means  119  and tray plate  116 , a conditioning unit  31 , a stretch blow molding unit  40 , wherein in an open stretch blow mold assembly  83  external components  92  are going to be placed by a transfer component device assembly  90  in a component release position  94  and a universal gripper assembly  27  mounted on a robot  28  in a gripper waiting position  81  and a finished hollow article discharge unit  58 . 
     FIG. 9 shows a schematic side view of a robot  28  with a universal gripper assembly  27  in a waiting position  81  and a transfer component device assembly  90  holding on the front and back side external components  92  in a component release position  94 . 
     FIG. 10 is a schematic top view of a stretch blow molding sequence showing from right to left a plasticizer  10 , a preform molding unit  12 , a tray unit  115  in a discharge position, a conditioning unit  31 , a stretch blow molding unit  40 , wherein in the open stretch blow mold assembly  83  external components  92  had been placed during the gripper-waiting phase, and a universal gripper assembly  27  mounted on a robot  28  holds molded preforms  89  placed between the closing stretch blow mold assembly  83  in a stretch blow molding position  97  while a transfer component device assembly  90  located above the oriented discharge unit  58  picks up external components  92  from the front and back component dispensing cartridges  91  in its component pick-up position  95 . 
     FIG. 11 shows a schematic side view of a robot  28  with a universal gripper assembly  27  ready to pick up preforms  89  from a tray plate  116  and a component transfer device assembly  90  in a component stand-by position  98  holding front and back components  92 . 
     FIG. 12 is a top view of a single-row stretch blow mold apparatus showing from right to left: a plasticizer  10 , a preform mold cavity assembly  26 , in a preform molding unit  12  with a tray unit  115 , a set of heat pots  36  in a conditioning unit  31 , a single-row blow-mold assembly  83  with pivoting spacing platens  44  and a stack blow-mold clamp moving means  46  in a stretch blow molding unit  40 , positioned in line to a traversing robot  28  with a universal gripper assembly  27  mounted onto a traversing beam  61  and its vertical upper moving means  29  also attached to a traversing beam  61  releasing finished hollow articles onto a lateral oriented discharge unit  58 . A multitude of cut-outs in the gripper arms  99  at a multitude of mold cavity center distances allow transfer of preforms and hollow articles with different neck finish sizes at predetermined center distances. 
     FIG. 13 is a top view of a single-row stretch blow mold apparatus as shown in FIG. 12 in which the plasticizer  10 , the preform mold unit  12  with a preform-mold-cavity assembly  26  and the tray unit  115 , the conditioning unit  31  with a set of heat pots  36 , the stretch blow molding unit  40  with a single-row blow mold assembly  83  with pivoting spacing platens  44 , have been turned perpendicular to a traversing robot  28  with a single-row universal gripper assembly  27  and vertical moving means  29 , located on the traversing beam  61 , releasing finished hollow articles onto an in-line oriented discharge unit. 
     FIG. 14 shows a schematic movement of a traversing robot  28  with a universal gripper assembly  27  for a stretch blow molding method and apparatus, starting from right to left at a molded-preform take-out position  77  at the tray plate  116  of a tray unit  115 , traversing to a preform-conditioning position  78 , descending onto a preform-stretch blow molding position  79  where the preforms are stretch blown into hollow articles, retracting to a finished hollow article oriented discharge position  80 , returning to a gripper-waiting position  81 , and ascending back towards a preform-pick-up position  82 . 
     FIG. 15 is a top view of a single-row stretch blow molding apparatus as described in FIG. 12 except between the preform mold unit  12  with its preform mold cavity assembly  26  and the conditioning unit  31  is installed a preform reheat unit  100 . The universal gripper assembly  27  has been pivoted into a preform take-out position  77  by gripper rotating means  101 , connected to the robot  28  to pick up reheated preforms  89  to be transferred through the conditioning unit  31 , the stretch blow mold unit  40  where they are transformed into hollow articles and released into the oriented discharge unit  58 . 
     FIG. 16 shows a schematic sequence from right to left of a robot  28  with a universal gripper assembly  27  pivoted by the gripper rotating means  101  into a preform take-out position  77 , then being returned by same gripper rotating means  101  into a basic traversing mode to enter a preform conditioning position  78  descending onto a preform stretch blow molding position  79 , where the preforms are being stretch blown into hollow articles, retracting to a finished hollow article oriented discharge position  80 , returning to a universal gripper preform pick-up position  82  or tray plate  116 . 
     FIG. 17 is a side view of a single-row stretch blow molding apparatus as described in FIG. 1 with a plasticizer  10  and a preform molding unit  12  with a tray unit  115  in a retracted position. A robot  28  with gripper moving means  29  is equipped with gripper rotating means  101  that pivot a universal gripper assembly  27  into a preform take-out position  77  to pick up preforms  89  from a lateral preform reheat unit  100  and returns to its basic position to guide the preforms through a conditioning unit  31  and a stretch blow unit  40  to be stretch blown into hollow articles  86  which are released in an oriented discharge unit  58 . 
     FIG. 18 is a top view of a single-row stretch blow molding apparatus as shown in FIG. 12, wherein a gantry robot  84  indexes together with a universal gripper assembly  27  along a lateral guide rail  85  to pick up molded preforms from a tray plate  116  with openings  120  of a tray unit  115  with moving means  119  collected from a preform-mold-cavity assembly  26  in the preform-molding unit  12 , and transfers the same into a conditioning unit  31 , descends into a single-row blow mold cavity assembly  83  in a stretch blow molding unit  40 , where preforms are stretch blown into hollow articles, and retracts into an oriented discharge unit  58  to release finished hollow articles  86 . 
     FIG. 19 is a top view of a multi-row stretch blow molding apparatus wherein a robot  84  indexes sideways together with a universal gripper assembly  27  along a lateral guide rail  85  to pick up molded preforms from a tray unit  115  with a multi-row of tray plates  116  collected from an opening preform mold cavity assembly  26  in a preform molding unit  12 , indexes the same into a conditioning unit  31 , descends into a multi-row stack-blow mold cavity assembly  41  in a stretch blow molding unit  40 , wherein the preforms are stretch blown into hollow articles, and retracts into an oriented discharge unit  58  to release the finished hollow articles  86 . 
     FIG. 20 shows a back view of a schematic movement of a laterally indexing robot  84  indexing sideways with a universal gripper assembly  27  starting from right to left, at a preform-take-out position  77  at a tray plate  116  with openings  120 , indexing to a preform-conditioning position  78 , descending onto a preform-stretch blow-molding position  79 , where the preforms are stretch blown into hollow articles, retracting to a finished-hollow-article-discharge position  80 , returning to a gripper-waiting position  81 , and ascending back towards a preform-pick-up position at the tray plate  116 . 
     FIG. 21 shows the top view of a one and a half step stretch blow molding assembly consisting of a plasticizer  10 , a preform molding unit  12  with a double row preform mold  26  and a tray unit  115  with the moving means  119  having the two rows of tray plates  116  with collected preforms  89  shifted outside the preform molding unit  12  into the conditioning unit  31 . A primary gantry robot  84  with gripper moving means  29  and universal gripper assembly  27  picks up conditioned preforms  89  from one row of the tray plates  116  transfers the same on a lateral guide rail  85  into the single row stretch blow mold assembly  83  of the stretch blow molding unit  40  and returns to a subsequent row of tray plates  116  ready to pick up the next fraction of molten preforms  89  while a secondary gantry robot  111  mounted onto the lateral guide rail  85  picks up finished hollow articles  86  from the stretch blow unit  40  and releases the same into the oriented discharge unit  58 ; 
     FIG. 22 shows the top view of a one-step stretch blow molding assembly consisting of a plasticizer  10 , a preform molding unit  12  with a multi-row tray unit  115  in a retracted position, its moving means  119 , the tray pates  116  and tray plate openings  120 , a conditioning unit  31  and a primary gantry robot  84 , mounted onto the lateral guide rail  85  with a universal gripper assembly  27  holding molten preforms  89 , a stack blow mold unit  40  with a multi-row stack blow mold assembly  41  and a secondary gantry robot  111  mounted onto a lateral guide rail  85  releasing finished hollow articles  86  onto an oriented discharge unit  58 ; 
     FIG. 23 shows the top view of a tray unit  115  mounted onto the tiebars  19  of a preform molding unit (not shown) extended into a discharge position whereby the moving means  119  have shifted the tray plates  116  with collected molten preforms  89  on linear rails  118  mounted onto the tray unit base  121  through telescoping means  126  and telescoping bushings  125  to align with the center row distances of the down stream units (not shown); 
     FIG. 24 shows the top view of a tray unit  115  mounted onto the tiebars  19  of a preform molding unit (not shown) in a retracted position whereby the moving means  119  have shifted the tray plates  116  together into the preform molding unit (not shown) to collect molten preforms in their openings  120 ; 
     FIG. 25 shows the front view of a tray unit  116  holding molten preforms with transfer beads  124  in the openings  120  of the tray plate  116 . The tray plate  116  sits on linear bearings  117  sliding on linear rails  118  attached to the tray unit base  121 , mounted onto the tiebars  19  of the preform molding unit (not shown) through telescoping means  126  and telescoping bushings  125 ; 
     FIG. 26 shows the front view of a tray plate  116  with catch baskets  123  holding molten preforms without transfer beads  122  in the openings  120 ; 
     FIG. 27 is a side view of a multi-row stretch blow molding method and apparatus showing from right to left a plasticizer  10 , a preform-molding unit  12  consisting of an upper clamp platen  13  with vertical clamp cylinders  14  and  15  connected to a frame-type clamp platen  16  holding the neck split mounting bars  17  and neck splits  18 . The frame-type clamp platen  16  slides up and down on tie bars  19  which are connected to the base platen  20  and the upper clamp platen  13 . An intermediary clamp platen housing  21  is connected to the frame-type clamp platen  16 . A central clamp cylinder  22  is mounted onto the intermediary clamp platen housing  21  which moves the injection core holding platen  23  with the injection core mounting bars  24  and injection cores  25 . A preform mold cavity assembly  26  with narrow center row distances is mounted onto the base frame  20 . The preform-molding cycle starts when the frame-type clamp platen  16  with the neck-split mounting bars  17  and neck splits  18  have been lowered onto the mold cavity assembly  26  by the vertical clamp cylinders  14  and  15 , and the injection cores  25  have entered the preform mold cavity assembly  26 . 
     Upon completion of the preform-molding phase, both the frame-type platen  16  and the intermediary clamp platen housing  21  are raised together by the vertical clamp cylinders  14  and  15 . A tray unit  115  is mounted onto the tiebars  19  of the preform molding unit  12  holding molten preforms with transfer beads  124  in a telescoped center row discharge position corresponding to the center row distances of the downstream units. A universal gripper assembly  27 , mounted onto a robot  28  with a vertical moving means  29 , slides on track rails  30  above the tray plates  116  of the tray unit  115  to lift the molten preforms  124  out of the tray plate openings  120  and guides them to the conditioning unit  31 . The preform-mold cavity assembly  26  is closed again to mold a new set of preforms. The conditioning rods  32  held by individual mounting bars  9  and mounted upon the base plate  33 , connected to a central conditioning rod clamp cylinder  34  and guide rods  35 , descend into the preforms (not shown). A set of heat pots  36  are raised around the preforms (not shown) by central raising means  37  and aligned by guide rods  38  mounted on a base unit  39 . Upon completion of the conditioning phase, the conditioning rods  32  and the heat pots  36  retract. The universal gripper assembly  27  indexes the preforms into the stretch blow-molding unit  40  and lowers them into stretch blow molds  41  with the gripper moving means  29 . Bottom plugs  42  are raised by bottom plug moving means  43 . Rotating means  45  pivot spacing platens  44  to close the blow-mold halves  41 . The blow-mold clamp assembly  46  with synchronizer (not shown) generates the final clamp closing pressure. Simultaneously, blow cores  47  held by blow core holding bars  48 , mounted onto a frame-type blow-core clamp platen  49 , are lowered onto the preforms (not shown), held in the closed blow-mold cavities  41  by vertical moving means  50  and  75 , mounted onto the upper moving means platen  51 . Intermediary stretch-rod clamp-platen housing  52 , mounted onto the frame-type blow-core clamp platen  49  follows the blow-core movement. Central stretch-rod moving means  57 , mounted onto the intermediary stretch-rod clamp-platen housing  52 , connected to the stretch-rod holding platen  54 , with the stretch-rod mounting bars  55  holding stretch rods  56  and moves stretch rods  56  into the preforms (not shown). Upon completion of the stretch blow phase, vertical stretch blow moving means  50  and  75  as well as stretch-rod moving means  57  retract to their upper positions, the universal gripper assembly  27  is raised by the gripper moving means  29  and retracts the finished hollow articles  86  to an oriented discharge unit  58  before returning to the waiting position at the tray unit  115 ; 
     FIG. 28 shows the same side view of a multi-row stretch blow molding apparatus as described in FIG. 27 except beneath the tray plates  116  are mounted catch baskets  123  to carry collected molten preforms without tranfer beads  122 ; 
     FIG. 29 shows a top view of a stretch blow molding method and apparatus consisting of plasticizer  10 , preform molding unit  12 , tray unit  115  with telescoping rod moving means  119  to align the tray plates  116  with collected molten preforms  89  from the narrow center row distances of the preform mold cavity assembly  26  to the center row distances of the down stream units, the conditioning unit  31 , the stretch blow molding unit  40 , all equipped with upper moving-means platens  13 ,  8 , and  51  holding vertical clamping means  14 ,  15 ,  34 ,  50 , and  75 , respectively. Beneath are located the intermediary clamp platen housings  21  and  52  holding central clamp cylinders  22  and  57 . Central clamp cylinders  22 ,  34 , and  57  are connected to holding platens  23 ,  33 , and  54 , respectively, under which are held in place on individual mounting bars  24 ,  9 , and  55  the injection cores  25 , the conditioning rods  32 , and the stretch rods  56 , respectively. Beneath the holding platens  23  and  54  are located the individual mounting bars  17  and  48  to hold the neck splits  18 , and blow cores  48  onto frame-type clamp platens  16  and  49 , respectively, with elongated mounting holes  74  which permit variations in the center row distances according to the preform mold cavity center distances. Mounting bars  9  for the conditioning rods are bolted in elongated slots  74  onto the holding platen  33 . The top view further shows a universal gripper assembly  27  with opening and closing means  63  mounted onto a robot  28  monitored by a drive  62  and gripper moving means  29  and an oriented discharge unit  58  beneath. A multitude of cut-outs in the gripper arms  99  at a multitude of mold cavity center distances allows to transfer preforms and finished hollow articles with different neck finish sizes and predetermined center distances; 
     FIG. 30 shows the top view of a robot  28  with vertical moving means  29  and a universal gripper assembly  27  consisting of telescoping rod moving means  130  and gripper components  132  retracted by a telescoping rod  131  into a molten preform  122  pick up position. The component support rails  134  are mounted onto the robot  28  with sliding mounting bolts  136  and connected to gripper opening and closing means  63 . A push-pull bar  135  connected to the telescoping rod moving means  130  and the telescoping rods  131  provides the retracting movement for the gripper components  132  to pick up molten preforms  122  with the gripper component cutouts  99  from preform molds (not shown) with narrow center distances and the telescoping movement as shown in FIG. 31 to subsequently align the molten preforms  122  to the larger center distances of the blow mold cavities (not shown); 
     FIG. 31 shows the top view of a robot  28  as described in FIG. 30 except the gripper components  132  are now telescoped into the above described extended position  133  to align the molten preforms  122  to the larger center distances of the blow mold cavities (not shown); 
     FIG. 32 shows the front view of a robot  28  as described in FIG. 30 with vertical moving means  29  and a universal gripper assembly  27  slidable on the support rails  134  by a telescoping component rod  131  holding a molten preform  122  with the cut-outs  99  of the gripper components  132  and the opening and closing means  63 ; 
     FIG. 33 shows the top view of a one and a half step stretch blow molding assembly with a plasticizer  10 , a preform molding unit  26  with a two row preform mold  26  and a tray unit  115  with moving means  119  having the extended two rows of tray plates  116  with molten preforms collected in the openings  120  shifted outside the preform molding unit  12  into the conditioning unit  31 . A gantry robot  84  with a universal gripper assembly  27  mounted onto a lateral guide rail  85  picks up sequentially fractions of molten preforms from the tray unit  115  and transfers them to the single row blow mold assembly  83  in the stretch blow molding unit  40  and subsequently into the oriented discharge unit  58 ; 
     FIG. 34 shows the top view of a multi row one and a half step stretch blow molding assembly with two plasticizers  10  an  11 , a preform molding unit  12  with a multi row preform mold  26  and a multi row tray unit  115  having moving means  119  to telescope the tray plates  116  with molten preforms  89  into a conditioning unit  31  so that their center row distances are aligned with those of the stack blow mold assembly  41  in the stretch blow mold unit  40 . A gantry robot  84  mounted onto a lateral guide rail  85  with a universal gripper assembly  27  and telescoping gripper components  133  picks up a fraction of molten preforms  89  from the extended tray plates rows  116  guides and holds them in the stack blow mold assembly  41  with the closing means  46  and spacing platens  44  of the blow mold unit  40 . Upon completion of the stretch blow cycle the same gantry robot  84  lifts and releases the finished hollow articles  86  onto an oriented discharge unit  58  beneath prior to returning to the tray unit  115  to pick up a next fraction of molten preforms  89 ; FIG. 35 shows the top view of a one and a half step stretch blow molding assembly as described in FIG. 34 except the conditioning unit  31  is installed adjacent to the preform molding unit  12  and the telescoping tray unit  115  to enable to condition the molten preforms  89  being picked up in fractions by a gantry robot  84  with a telescoping universal gripper assembly  27  from the tray plates  116  at varying time intervals; 
     FIG. 36 shows the schematic movement of a robot  28  with a universal gripper assembly  27  from right to left at a fractional pick up position of molten preforms (not shown) from a tray plate  116  mounted onto a tray unit base  121 , traversing a conditioning unit  78 , descending onto a stretch blow molding unit  79 , retracting to an oriented discharge unit  80 , returning to the tray unit  116  to pick up a subsequent fraction of molten preforms (not shown); 
     FIG. 37 shows the top view of a multi row one and a half step stretch blow molding assembly as described in detail in FIG. 34 except the assembly is equipped with a second multi row blow mold assembly  41   a  in a second stack blow mold unit  40   a  and a second robot  28   a  with a telescoping universal gripper assembly  27   a  and second oriented discharge unit  58   a  to either double the output of hollow articles or produce different hollow articles from the same preforms simultaneously; 
     FIG. 38 is a top view of a multi-row stack-blow mold cavity assembly  41  in a closed position with pivoting spacing platens  44  in an extended position driven by rotating means  45 , accelerated by helical spindles  140  and  143  with helical nuts  141  and  142 , wherein the stretch blow mold mounting platens  68  are directly attached and extended by a hinge mechanism  69 . Floating center-cross bars  70 , attached to blow-mold tie bars  66 , serve as center pivot points for the center axes  71  of the pivoting spacing platens  44 . Synchronized blow-mold clamp platens  67  mounted onto blow mold tie bars  66  generate the necessary clamp closing force via closing means (not shown); 
     FIG. 39 shows a top view of a multi-row stack-blow mold cavity assembly  41  in an open position with pivoting spacing platens  44  and hinge mechanism  69  in a retracted position and helical spindles  140  and  143  with helical nuts  141  and  143 . Bottom plug rows  72  and bottom-plug-moving means  43  are shown between the open multi-row stack blow mold halves  41 . Blow mold clamp means  46 , monitored by a clamp platen synchronizer assembly  73 , open the outer blow-mold clamp platens  67  attached to blow-mold tie bars  66 . 
     FIG. 40 shows a side view of a stack-blow mold cavity assembly  41  mounted on a base frame  65  in a closed position with pivoting spacing platens  44  and hinge mechanism  69  in an extended position driven by rotating means  45  connected to spacing platen rotating gears  64  by an endless drive belt  144 , and right turn as well as left turn helical spindles  140  and  143  mounted onto the front and rear blow mold clamp platens  137  and  138  as well as right and left thread helical nuts  141  and  142  mounted onto the intermediary blow mold clamp platens  67 , driven by synchronizing moving means  46  and  73  mounted between the rear blow mold clamp platen  137  and the blow mold assembly back platen  139  connected via tie bars  66  to the front blow mold clamp platen  138  and the mold height adjustment nuts  145  toothed belt  146  and electric drive (not shown). Bottom plug rows  72  and bottom plug moving means  43  are shown between the closed multi-row stack blow mold halves  41 . Floating center cross bars  70 , attached to the blow mold tie bars  66  serve as a center pivot point for the center axes  71  of the spacing platens  44 . 
     FIG. 41 shows a side view of a stack-blow mold cavity assembly  41  in an open position, as described in detail in FIG. 40 with front and rear blow mold clamp platens  137  and  138  as well as intermediary blow mold clamp platens  67  inter connected with tie bars  66  to a blow mold clamp back platen  139 , synchronously driven by moving means  46  and  73  in conjunction with pivoting spacing platens  44  and right turn as well as left turn helical spindles  140  and  143  with helical nuts  141  and  142  and mold height adjustment nuts  145  and toothed belt  146 ; 
     FIG. 42 is a sequential side view from right to left of a molded preform  89  with a neck section  108  at an elevated temperature to receive an internal component before the shrinkage phase has been completed. An internal component pick-up and inserting device  109  having positioned an internal component  103  in the neck section  108  of a molded preform  89  while still at an elevated temperature. An internal component  103  is shrunk into the neck section  108  of a stretch blown hollow article  86  during the conditioning, the stretch blow and the cooling phase. 
     FIG. 42 a  is the same sequential view shown in FIG. 42 with the exception that an internal component  103  with inner liner  114  has been placed in a molded preform  89  while still at an elevated temperature. The molded preform  89  is being stretch blown into a multi-layer hollow article  86  with an internal component  103  and inner liner  114  in intimate contact with the neck  108  and body portion of the hollow article  86 . 
     FIG. 43 is a side view of a multi-row stretch blow molding apparatus as described in detail in connection with FIG. 27 showing from right to left a plasticizer  10 , a preform molding unit  12  with a tray unit  115  holding molten preforms with transfer beads  124  on their telescoped tray plates  116 , with an internal component sorting unit  102  and an indexing sorting conveyor  104  which brings internal components  103  beneath a multitude of internal component pick-up and inserting devices  109 . The component pick-up and inserting devices  109  are lowered towards the internal components  103  or internal components with inner liners  114  (not shown) in position on the indexing sorting conveyor  104  by moving means  112  and pick up the internal components  103  through monitoring motions of the central moving means  113 . Internal components  103  are held in a waiting position (not shown) until the tray unit  115  transfers the molded preforms with internal component preparation  108  (not shown) at elevated temperature in position and then places the internal components  103  (not shown) or internal components with inner liners (not shown) into the molded preforms (not shown) prior to the completion of the shrinkage phase of the molded preforms. 
     The reinforced molded preforms (not shown) are then transferred by the universal gripper assembly  27  to a conditioning unit  31 , lowered into a stretch blow molding unit  40  and transformed into hollow articles  86  with reinforcing internal components  103  (not shown) or internal components with liners  114  (not shown) are stretch blown into multi-layer hollow articles (not shown) which are retracted onto an oriented discharge unit  58 . 
     FIG. 44 shows a side view of a multi-row stretch blow molding apparatus as shown in principal in FIG.  28  and described as well in FIG. 43 except the tray unit  115  is holding on their telescoped tray plates  116  with catch baskets  123  molten preforms without transfer beads  122 ; 
     FIG. 45 is a top view of a multi-row stretch blow-molding apparatus as described in detail in connection with FIG. 35 showing from right to left the plasticizers  10  and  11 , respectively, the preform molding unit  12 , with a tray unit  115 , a sorting unit  102  to line up internal components  103  or internal components with inner liners  114  (not shown) onto an indexing sorting conveyor  104 , a conditioning unit  31 , a stretch blow unit  40 , a primary gantry robot  84 , with a universal gripper assembly  27  mounted on a lateral guide rail  85 , as well as a secondary stretch blow molding unit  105 , an oriented discharge unit  58  beneath a secondary gantry robot  111  with a universal secondary gripper assembly  106  mounted onto a secondary traversing beam  107 . 
     FIG. 46 shows a schematic side view sequence basically described in connection with FIG. 36 of a robot  28  with a universal gripper assembly  27  from right to left starting at a molded preform pick up position  77 , indexing to an internal component inserting position  110 , traversing to a preform conditioning position  78 , descending onto a preform stretch blow molding position  79 , leaving the pretreated molded preforms in a blow-mold assembly  41  (not shown), returning to a gripper-waiting position  81 , and ascending back towards a preform pick-up position  77  at a tray unit plate  116 . 
     Simultaneously, a secondary robot  111  with a universal gripper assembly  106  picks up the pretreated molded preforms  89  (not shown) from the position  79  and transfers the same into a secondary or a multitude of subsequent stretch blow molding positions  97  prior to releasing the finished hollow articles in an oriented discharge position  80 . 
     It will be understood by those skilled in the art that each of the elements described above, or two or more together, may also be used in alternate methods of producing molded articles therein and in other methods and apparatuses for the preparation of molded articles. 
     While the invention has been described in detail in the foregoing specification and drawings as embodied in the context of a single-row and a multi-row stretch blow molding method and apparatus for the preparation of molded articles, it will be appreciated that the description is not intended to be limited to the details shown and various modifications and structural changes may be made without departing from the spirit and scope of the invention.