CA1066009A - Apparatus for continuous stretch-blow molding operation - Google Patents

Abstract

APPLICATION FOR
LETTERS PATENT
FOR

METHOD AND APPARATUS FOR
CONTINUOUS STRETCH-BLOW MOLDING

ABSTRACT OF THE DISCLOSURE
Apparatus for continuously forming molecularly oriented articles generally comprising a multi-station rotary stretch-blow molding machine wherein a plurality of partible blow molds angularly spaced about a continuously rotating support are provided with mold moving means for moving the mold sections of said molds between open and closed positions in synchronization with rotation of said support, stretch rod positioning means to longi-tudinally reciprocate a stretch rod within a cavity of each of said molds and second stretch rod positioning means for projecting the rod into the cavity and retracting it therefrom, said stretch rod positioning means being operable in combination and in synchronization with said mold movements. Another feature of this invention involves means for continuously and simultaneously feeding workpieces to and discharging articles from a stretch-blow mold machine.
From a process standpoint, the workpiece, while at molecular orientation temperature, is held temporarily or stored at each moving mold while an article is being formed in the cavity of such mold from a prior preform.
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Description

This inVention relates to method and apparatus for continuously forming molecularly or~ented articles generally comprising a rotary ~tretch-Blow mold machine.
While the blow molding art goes back over one hundred years, it has only been in the last twenty years or so that blo~ molding of hollow plastic articles such as containers has achie~ed significant commercial success. Along with the increased interest in blow molding techniques has come the strong desirability ~or improving the strength and other properties of finished containers prepared in this manner.
Known ways of improving strength in plastic containers include changing the chemical structure of the plastic material during synthesis by means of strength imparting modifiers or increasing the wall thickness of the finished article. The former way may undesirably affect other properties of the material while the latter could be rather costly.
Another attractive way of improving the strength properties of a finished container involves the molecular orientation of the thermoplastic material being blow molded into the container. Generally speaking, molecular orientation of a s-~itable thermoplastic material is obtained by stretching such material while in the solid state at a temperature just below its cr~stalline melting point. However, while orientation can result in a su~stantial increase in tensile strength it cannot be obtained using a conventional blow molding operation.
One method of obtaining the desired oriented product is shown in Wiley et al, U.S. Patent No. 3,507,005 and involves extruding a hollow parison, cooling it to room temperature, carefully re-heating it to just ~elow its crystalline melting point, grasping the parison at one end while pinching or clamping it at the '~

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other end and stretch~ng Lt longitudinally. Then while still held at the ~irst end the parison is enclosed in a mold and blown to conform to tne shape thereof. Such a process is some-what complex and does not readily lend itself to the high speed fabrication which is desired in a successful commercial operation. Another method for preparing oriented containers involves the initial preparation of an elongated thermoplastic workpiece such as a prePorm closed at one end. The preform is then brought to the necessary temperature and placed in an enclosed mold oVer a rod which is extended to stretch said preform after ~hic~ it is blo~n using pressurized air to obtain an article having the des~red biaxial orientation. While such method represents an attractive way to prepare oriented containers, it must ~e carried out in apparatus suitable for high speed fabrication to make it economical.
Although a large number of blow molding devices ;` suitable for continuous high speed production have been ; disclosed, most are directed to the conventional, non-orientation blow molding process and do not concern themselves ~ith the ~ethod wherein a rod is extended and retracted in the mold during fa~rication of the container.
; The present invention relates to an apparatus and ; method capa~le of continuously forming molecularly oriented ~ articles, said apparatus comprising a multi-station rotary stretch-blow molding machine particularly adapted for rapid < feeding and discharging from said machine.
More specifically, t~e present invention provides an apparatus for continuously forming molecularly oriented articles generall~ comprising a plurality of radially partible blo~ moIds disposed at angular intervals on a support mounted on a frame and adapted for continuous rotation about a substantially vertical axis, mold moving means for moving the , ,~.. , . , . _ .... _. . .

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mold sections of said molds ~etween open and closed positions in synchron~zation wi~th rotation of said support, strPtch rod means for each mold opera~le in comhinat;on w~th said mold mov~ng means and ~ncluding stretch rod positioning means for longitudinally reciprocating a stretch rod while within a cavity of said mold, pressurized fluid means associated with said stretch rod and a vertical container discharge chute in the vicinity of the cavity of each mold.
In another em~odiment of this invention, a stretch-blow mold machine having a stretch rod which is reciprocally movable both within the mold cavity and into and out of the cavity is provided ~ith feeding and discharge means for simultaneously feéding a workpiece while discharging a molecularly or~ented blown article.
From a process standpoint, there is provided in the process of blow molding articles from preforms which includes the steps of positioning such preforms within cavities of continuously moving and successively presented blow molds "
; distending the preforms within the moving molds to form the articles and discharging the art;cles from the still-moving molds at an eject station prior to charging with additional preforms, the improvement comprising holding or storing a preform temporarily at each such moving mold while an article ' is being formed in the cavity therein from a prior preform.
~ In describing the overall invention, reference will ; be made to the accompanying drawings wherein:
FIGURE 1 is a schematic side elevational view showing one mold station of the rotary blow molding machine and~incor-porating the novel apparatus components of this invention;
FIGURE 2 is a schematic plan view showing one mold station of the rotary blow molding machine;
;~ FIGURE 3 is a schematic front elevational view of one mold station of the rotary blow molding machine; and .. . . . .

FIGU~ES 4 to 11 are partially sectioned elevational side views showing the sequence of operation of one mold station at various times during i~ts rotation a~out the rotary support, Referring to the drawings, there is illustrated in Figure 1 a rotary ~low molding machine designated generally as 10 for cont~nuously forming molecularly oriented articles such as containers and part~cularly bottles. Only one mold station is shown, however a plurality of identical mold stations are equally spaced at intervals around the periphery of the supportLng structure.
Blow mold`machine 10 comprises a vertical shaft 12 carrying a huh 14 for continuous rotation therewith by conventional drive means such as a motor, gear reducer, or the like~ not shown, ~ixedly attached to hub 14 is a circular mold supporting plate 16.
A plurality of identical mold units generally ; indicated by the numeral 1~, only one of which is shown and which ~ill be descriBed hereafter in detail, are equally spaced about the supporting plate 16.` Each of the mold units s 18 comprise partible mold sections 20a and 20b which in the closed position define cavity 22, the surface of which conforms to the shape of the body of a hollow article such as a bottle to be molded therefrom from a thermoplastic material (see Figure 8~o Mold sections 20a and 20b may be convention-ally secured ~e,g. by bolts or clamps) in mold platens or carriers 24a and 24~,which in turn are operatively associated with the remainder of the apparatus in a manner to be described hereafter ~n more detail.
Each platen 24a and 24b of partible mold unit 18 is ~ ;
slida~ly supported by guiae rods 26, 28, 30 and 32 which also maintain the alignment of the platens and attac~ed molds . -., .. . ~ : . .

(see Figure 3L. The ~our guide rods are f~xedly attached to the support~ng structure w~ich l~s mounted on t~e support~ng plate 16.
Outer mold sect~on 20~ and platen 24b is reciprocally moved between open and closed positions by the movement of'tie roas 34 and 36 ~igure 2~ which are secured to the platen by any conventi~onal means and ~llustrated e.g. by bolts (Figure 1).
There are provided actuat~on means for synchronization of mold movement w~th the rotation of the supporting plate 16 through the use o~ a scotch yoke assem~ly, or equivalent, as described below.
~ s ~llustrated in F~gure 1 mold opening and closing cam 38 is fi~edly attached to the base of the machine. Cam roller or follower 40 ~s attached to lever 42 and moves within the contoured slot 44 found in cam 38. Lever 42,is connected to shaft 45 through detent Ctorque limiting device) and gear assembly 46. The shaft 45 is connected to a cam or eccentric member 48 and this to a pair of crank or lever arms 50a and b.
The lever arms are connected through connecting pin 52 and bearing 53. Lever arm 50b is attached to another cam 54.
Bearing 53 is free to move about the conn,ecting pin and fits into a slot 56 on plate 58 of the scotch yoke assembly (Figure

2). Tie rods 34 and 36 which are secured to the outer mold section 20b and platen 24b are fixedly attached to plate 58 of the scotch yoke assembly and reciprocally move in a lateral direction with rotation of the shaft 45 through the action of the components described above.
Inner mold section 20a and platen 24a also move with rotation of the s~aft 45 but to a lesser degree than the outer mold. This is accomplished through the interaction of cams 48 and 54 and their associated rollers 60 and 62. The rollers are attached to platen 24a ~hich in turn is supported and reciprocall~ slides on guide rods 26, 28, 30 and 32.

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Inner mold sect~on 20a is ~oyed throu~h the force of spring5 26c and 28c pos~tloned on gu~de rods 26 and-28 respectively CF~gure 1~ and those on gu~de rods 30 and 32 (not shown) which push aga~nst platen 24a and the rollers 60 and 62'as cams 48 and 54 moYe to the le~t when the mold is opening.
In synchronization with movement of the mold sections, the stretch rod 64 ~s ~ein~ moved to the desired operating positions as follows:
Stretch rod 64 is moved between its fully extended position ~Figures 4 and 7~ and its position just prior to the start of the stretching operation (Figures 5 and 6) through the movement o~ housing means such as air cylinder 66 by the action of air cylinder cam 68 and air cylinder cam rollér (followerl 70. Stretch rod 64 is affixed to the air cylinder shaft (not s~o~n) in air cylinder 66 and moves in combination with said air cylinder and shaft. Air cylinder 66 is connected to cam roller 70 ~y ~racket 74. Bracket 74 and air cylinder 66 slide in ways or tracks ~not shown) in the supporting structure or frame designated generally as 77 which is attached to rotating support 16. As the support 16 rotates, air cylinder 66 moves in the tracks via interaction with cam roller 70 which moves within the slot 72 of cam 68 which is fixedly attached to the non-moving base of the machine. Cam 68 shown ; - as a box cam travels a]l the way around the rotary machine .~ , , and depending on the shape or direction of the contoured slot 72, cam roller 70 and the connected air cylinder 66 and asso-ciated structural components move up and down as desired as the support 16 rotates. By this action stretch rod 64 is ~ ;
raised from the beginning of the stretch operation ~Figure 6) ; 30 to its fully extended position (Figure 7).

In the embodiment illustrated, the withdrawal of stretch rod 64 from the mold cavity 22, i.e. from its stretch .

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beginning or after blo~ position (Figure 6 and 8) to its com-plete removal from the cavity CFigures g and 101 is carried out ~y the appl~cation of a~r to t~e top side of the piston (~o~ shown) ~n a~r cylinder 66. This causes the shaft attached to the piston and the connected stretch rod 64 to be pushed downward lowering said rod ~nto sealing plug 76 as shown in Figures 9 and 10. Application of air pressure is through valve 79 and actuation of this valve is via valve actuation means.
Actuation of this valve is caused through interaction of cam 81, 1~ fixed to the base of the machine, and cam roller 83 connected to the valve ~y rod or shaft 85. The valve 79 is affixed to ; the supporting structure 77 in a conventional manner not shown and rotates with said structure as support 16 to which it is attached is rotated. The cam roller 83 travels along cam 81 completel~ around the machine and by its movement it changes the direction of valve 79 causing air to be applied to one side or the other of the piston in the air cylinder thereby raising or lowering the stretch rod 64. Air is also being applied when the stretch rod is ~eing moved within the cavity by the inter-2Q action of cam 68 and cam roller 70. This air is applied to the bottom of the piston in air cylinder 66 through air valve 79 and keeps the stretch rod 64 extended during this part of the cycle. The actual air supply connections from valve 79 to the air cylinder 66 has not ~een shown so as not to further complicate the drawings and distract from the essential features of this invention.
In the embodiment illustrated in Figures 7 to 10, neck jaws 78a and 78b open and close around the neck of the workpiece and blown article through the movement of air cylinders 88 and 90 3a ~hich are affixed to the mold sections 20a and 20b and platens 24a and b, T~e respective ~aw~ can be further moved, for reasons to ~e described ~elow, By movement of the respective pistons ' ' ~)6~
and connected s~afts of the air c~lInders 88 and 90.
Actuation of such mo~ement can ~e by any of the conventional means, not shown, such as a cam or dog fixed to the base of t~e machine wh~ch tr~ps lim~t sw~tches to open or close the air supply valve.
Sealing plug 76 is moved up to seal the neck of the workpiece and the stretch rod when the mold is closed through means of sealing plug cam 80 and sealing plug cam roller 82 CFigure 1~. Cam 80 is attached to the non-moving base of the machine and cam roller 82 travels in an up and down manner along the cam there~y moving the sealing plug which is attached to it via the action of lever 84 and eccentric member 86 as the support 16 rotates. Spring 87 CFigure 1) holds the plug 76 when it is in sealing engagement and thus cam 80 does not have to completely go around the machine and may only be placed in positions where the sealing plug 76 is to be lowered. In other words the cam roller 82 can be allowed to travel freely until it again engages the cam 80.
As shown in Figures 4 to 11 feeding and discharge 2Q means are provided to rapidly feed workpieces 92 and discharge blown articles 98 ~rom eac~ stretch-blow mold. A plate 94 is af~ixed to outer mold section 20b a~d platen 24b~and moves ~-in a lateral manner along with the movement of such parts through .. :
rotation of support 16 and the means described above. The ~ workpiece or preform 92 is dropped into guide means, i.e. a chute or funnel 96 preferably located in the vicinity of the cavity of each mold station ~y a conventional pick and place device or other means. The vertical chute or workpiece-holder 96 is supported in a conventional manner, not shown, preferably 3Q - by support 16 or by some other structure or apparatus and along with plate 94 provides a means for guiding and retaining the workpiece 92 until t~e mold ~as opened and stretch rod 64 is in position to receive ~t and start t~e sequence for forming an .. ~ , .

1~6~0~5 article, At the same tLme, a blown article such as bottle 98 is being d~scharged from the mold through opening 100 in support 16, associ~ated Wl`t~ a conventional discharge chute, as shown. ~lternat~vel~, such discharge opening and chute supported from support 16 could be upwardly disposed on the' axis at cavity 22 to accommodate an upwardly discharging system.
The bottle 98 is retained in the outer mold section 20b by re-taining means comprising the overlay section at the top of outer mold 2ab and through ~aw means i.e. the right neck jaw 78b which has a shape or configuration which surrounds a significant portion or section of the neck of the bottle 98 ~Figure 10~. Thus the bottle moves with the right hand mold 20b and neck ~aw 78B. When the bottle is generally over open-ing 100 (Figure 11~, the neck jaw 78b is pushed laterally to the left by actuation of releasing means comprising air cylinder 90 and its connecting shaft thereby releasing the bottle from the mold section of half 20b.
In alternat~ve systems to that just described, for example one wherein the articles are discharged upwardly from the open mold, cylinder 66 and its associated air circuitry may not be required since it will not be necessary to completely extract rod 64 from the mold cavity with such systems. Or, even with such just-described arrangement, it may be possible via proper cam designs to retract the rod from the cavity via t'ne mechanical cam-follower system above described.
To put the apparatus in proper perspective and par-ticularly to describe the synchronized action of the respective components, the operation will be described with particular reference to Figures 4 to ll which show the sequence~of events taking place in one selected mold at different times as the support 16 is being rotated.

The operat~on begins as shown in Figure 4 when a new workpiece 92 such as-a previously formed thermoplastic preform.
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which has ~een reheated to or~ent~tion temperature and having a tubular body with one open end and one closed end is dropped onto a ~ully extended stretch rod 64 and a formed bottle 98 is ~fully separated from mold sect~on 20~ and beginning its descent through discharge opening 100. The preform 92 is free to drop onto the rod extending upwardly on the axis of t~e mold cavity since plate 99 has been moved along with mold section 20b and platen 24b thereby clearing the lower end of chute 96 above the now open mold.
In the next step shown in Figure 5, the bottle 98 is now dropping out o$ t~e mold cavity into opening 100 and optional chute or funnel 102. During this time the stretch rod 64 holding the ne~l~ charged preform ~2 is retracting (lowering) to its normal start ~stretch beginning~ position. This is carried out by rotation of support 16 causing cam roller 70 to move within the slot 72 to the lower position in cam 68.
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The air cylinder 66 being affixed to the roller through bracket , ~ ,: , 74 thereby moves in tracks in the frame or supporting structure lowering the stretch rod 64 and the preform 92 to its position where stretching ~egins. Application of air to the lower s~de of the piston in air cylinder 66 keeps the stretch rod 64 stead~ during movement and also retains it in the position to which lowered through the action of cam 68 and ; cam roller 70 (see Figure 1~.
~s the support 16 continues to rotate, the mold sec-tions 20a and 20b and their respective platens 24a and 24b are beginning to close as shown in Figure 6. This happens through interaction of the mold opening and closing roller 40 ~-in the contoured slot 44 of mold opening and closing cam 38 ~igure 11. The roller 4a moves ~ith rotation of the support 16 causing the shaft 45 to rotate through the action of connecting lever 42 and thereby causes the scotch yoke assembly and particularly lever arms 50a and 50b to rotate. This ., , -ln-- , -- -- .. .. _ . . ...

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action causes the tie rods 34 and 36 which are connected thereto to rec~procally ~oVe in a lateral direction thereby beginni~g to close outer platen 24~ and îts mold section 20~.
At the same tl~me ~nner mold section 20a is also moving toward a closed pos~tion through movement of cams 48 and 54 to the right causing rollers 60 and 62 to move in that direction along with platen 24a whic~ ~s attached thereto (see Figure 1~. It is to be noted that rotation of the scotch yoke assembly and particularly lever or crank arms 50a and 50b is desirably slightly greater than 180 to make the mold sections squeeze together w~en closed and there~y lock themselves through the added tension or clamping force. Cam 38 does not have to go completely around the machine and may only be placed in sections where opening and closing of the mold is desired.
As the mold sections 20a and 20b close, neck jaws 78a and 78b also close around the neck of preform 92 through moVement of air cylinders 88 and 90 which are attached to said mold sections and platens 24a and 24b. At the same time, the sealing plug 76 begins to move up through the action of sealing cam 80, sealing cam roller 82 and lever 84 as shown in Figure 6, When the mold sections 20a and 20b reach their ;; fully closed position as shown in Figure 7, sealing plug 76 moves up to seal the neck of the preform 92 and stretch rod 64.
After the mold closing action is complete and mold cavity 22 is fully sealed, the preform is distended. Pre-fera~ly, stretch rod 64 ~egins to rise via movement of cam roller 70 in cam 68 through continued rotation of support 16 ~see Fi~ure 1). This action causes the tightly held preform 92 to stretch longitudinally as stretch rod 64 approaches and reaches its fully extended position sho~n in Figure 7.
When stretch rod 64 is ~ully extended, pressurized air is -11~

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provided through open~ngs ~not shown) in stretch rod 64 via a~r supply means 55 causing stretch in the radial direc-tion, the preform 92 thus becoming fully stretched and biaxiall~ oriented. Blow a~r may alternately be provided through the seali~ng plug in a manner not shown.
Due to the clos~ng of the mold, plate 94 is returned to its position below chute 96 and a new preform 92a îs dropped ; into the chute by external means ~not shown) and retained or obstructed in its passage by said plate 94. The preform 92a is now ready for feeding to the blow mold station below (Figure 7). Holding or storing a preform 92, which has been inserted in holder 96 from an upstream station, temporarily in such holder 96 at each moving mold station while an article is being formed in such mold from a prior preform in the manner illustrated increases the period during which the mold may remain closed and functianing on the prior charged preform.
In other words, if the preform were to be charged directly to the mold from the prior upstream station, as opposed to merely dropping onto stretch rod 64 from a position already 2Q at such continuously moving station, the mold stations would have to remain open longer during each cycle, and thus for a system of equ~valent capacity to that illustrated, additional ;
stations would have to be added, thus increasing the complexity of the system. Therefore, system efficiency is substantially increased by loading individual preforms 92 at a charging station into holders 96 adjacent to and moving with such molds while articles are being formed within such molds from prior 1 preforms. The molds are then charged directly from such ` holders, preferably while the preforms are at molecular orientation temperature, during or after discharging articles formed from prior preforms from the molds at the eject station, and ~h~le the molds traverse a closed circular path.

,. '~ .-After completing the stretching and blowing operation, stretch rod 64 begL`ns to retract through the action of cam roller 70 ~n cam 68 via continued rotation of support 16. Stretch rod 64 then reaches its intermediate position ~ithin the cav~t~ 22 as shown in Figure 8.
Stretch rod 64 cont~nues to retract until it is free of thé mold cav~ty 22 as shown in Figure 9. This happens when continued rotation of support 16 causes cam roller 83 to move along cam 81 thereby actuating valve 79 allowing air to be applied to the upper s~de of the piston housed in air cylinder 66 push~ng attached stretch rod 64 in a downward position, The mechanical and pneumatic retracting actions described above may be carried out simultaneously. Simultan-eously, sealing plug begins to retract from its seated position to release the blow air from the blown bottle 98.
This is actuated through movement of roller 82 along cam 80 in cooperation with lever 84.
Stretch rod 64 and seal plug 76 is now fully re-; tracted and the mold sections 20a and 20b begin to open with continued rotation of support 16 through the action of roller40 and cam 38, reversing the closing operation described above ; (see Figure 10.) -The formed bottle 98 is carried along with the outer mold section 20b and is held there by the shape or configuration of the overlay at the top of said section (bottom portion of bot'tle) plus the configuration of the surrounding neck jaw 78b. To aid in the movement of the formed bottle 98 with outer mold sections 20b, as the mold begins to open neck jaw 78a is moved laterally to the right against the neck of said bottle by action of air cylinder 88 and its connecting shaft. This added force helps the outer mold section 20b retain the formed bottle when the mold seal is first broken and the respective mold halves are separatin~.

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l.~ti~009 As shown ~n Figure 11, the outer mold section 2~b has now moved into pos~tion generally above d~scharge opening 100 in support 1~. At this t~me, t~e bottle 98 is now released from its retent~on b~ outer mold section 20b by lateral movement , of neck jaw 7~b to the left through actuation of air cylinder 90 causing the nec~ of the bottle 98 and the bottom thereof (facing up~ to move clear of the mold section. At the same time stretch rod 64 ~egins to extend itself between the mold sections 2~a and 20b through the application of air to the lower side o~ the piston housed ~n cylinder 66, or alternatively ~ ;
via coaction bet~een follower 70 and cam 68 reversing the retraction procedure described above. Alternate means such as forced air means ma~ be provided in outer mold 20b to help push the bottle out.
When stretch rod 64 continues to fully extend itself between the open mold sections 20a and 20b as shown in Figure 4 the sequence is complete. This is caused by the moVement of cam roller 70 in cam 68 through continued rotation : of support 16, reversin~ the procedure described above for retracting stretch rod 64. Stretch rod 64 is now in positlon to receive a ne~ preform 92 and repeat the sequence of operation.
The embodiments described above show a preferred rotary stretch-blow molding machin,e wherein the operation of the blow molds are synchronized with movement of the respective stretch rods to provide a facility capable of preparing molecularly oriented articles in a rapid continuous - manner thereby saving time and also saving space by the compact-ness of the arranged equipment.
Variations in the equipment, as would be obvious to one of ordinary skill in the art, may be implemented. For example, the opening and closing moVements of the mold sections may ~e per~ormed in a more conventional manner, ;~

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wherein both mold sections are moved an equal amount. Ho~ever of course, the adv~nta~e of economiziny on space as presented by the preferred embod~ment o~ t~is invention is particularly strong when commerc~al operati~ons are involved. It is further noted that Both stretch rod positioning means may be actuated by mechanical means such as cams. However, it is considered more pract~cal for commerc~al operations to use the preferred combinat~on o~ mechanical and pneumatic means. While the actuation devices shown are a preferred embodiment, other lQ conventional electrical, mechan~cal, fluidic and instrumenta-t~on means may ~e used including for example electric timers, solenoids, cams, pneumatic and hydraulic cylinders, switches, etc.
The above description and particularly the drawings are set forth for purposes of illustration only and are not to be taken in a limited sense. Various modifications and alterations will be readily suggested to persons skilled in the art. It is intended, therefore, that the foregoing be considered as exemplary only and that the scope of the inven-2~ tion be ascertained from the following cl~ims.

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Claims (18)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Apparatus for continuously forming molecularly oriented articles having:
a) a frame;
b) a support on said frame mounted for continuous ro-tation about a substantially vertical axis;
c) a plurality of radially partible blow molds disposed at angular intervals on said support, each mold defining a cavity;
d) mold moving means for moving said molds between open and closed positions;
e) actuation means synchronizing said mold moving means with the rotation of said support; characterized in that a stretch rod means is provided for each individual mold for operation with an individual mold and operable in combination with said mold moving means and including:
i) first stretch rod positioning means for longitudinally reciprocating a stretch rod while within said cavity of said mold;
ii) pressurized fluid means associated with said stretch rod for expanding a work-piece into a formed article; and iii) second rod positioning means for projecting said rod into said cavity and extracting it therefrom;
said support having a vertical container discharge chute in the vicinity of the cavity of each mold.

2. Apparatus according to claim 1 characterized wherein said stretch rod positioning means comprises:
a) housing means for supporting the bottom of said stretch rod and adapted to reciprocally move in combination therewith;
b) cam means for longitudinally moving said housing and said stretch rod including a box cam mounted on said frame and a cam roller for movement within a contoured slot of said cam and operatively connected to said housing.

3. Apparatus according to claim 1 characterized wherein there is included a second stretch rod positioning means for projecting said stretch rod into said cavity and extracting it therefrom.

4. Apparatus according to claim 2 characterized wherein said second stretch rod positioning means for projecting said stretch rod into said cavity and extracting it therefrom comprises a valve means for supplying pressurized fluid to either side of a reciprocally movable piston located within said housing, said piston being fixedly attached to said stretch rod and movable therewith valve actuating means attached to said frame for actuating said valve upon rotation of said support to supply fluid to the selected side of the piston thereby longitudinally moving the stretch rod.

5. Apparatus according to claim 4 characterized where-in said mold moving means comprises a) first guide rod means attached to said frame for slidable supporting and guiding movement of said two mold sections of said partible molds;
b) second tie rod means attached to one of said mold sections and reciprocally movable therewith in a lateral direction;
and c) positioning means for laterally moving said second tie rod means including:
(i) scotch yoke assembly means attached to said second tie rod means;
(ii) rotating shaft means for operatively working in engagement with said scotch yoke assembly to provide reciprocal movement to said attached second tie rod means;
(iii) cam means for providing rotational movement to said rotary shaft in synchronization with movement of said support and including a box cam affixed to said frame and a cam roller for movement within a contoured slot of said box cam and operatively connected to said shaft by lever means.

6. Apparatus according to claim 5 characterized wherein feeding and discharge means are included to continuously feed preforms to and discharge articles from said mold and including:
(i) plate means positioned above said mold for selectively obstructing passage of a preform to said mold cavity, said plate means adapted to reciprocally move in combination with one of said mold sections;
(ii) guide means associated with said plate means and fixedly positioned above said plate means and the center of said cavity so as to retain a preform on said plate means above the center of said mold cavity when said mold is closed and until said plate means has moved past the center of said cavity clear-ing the obstruction;
(iii) retaining means for releasably retaining a formed article in one mold section while said section is moving to open said mold including:
a) an overlap section at the top of said mold section and b) jaw means positioned at the bottom of said mold section and surrounding one section of the formed article and adapted to reciprocally move in combination therewith; and (iv) releasing means associated with said jaw means for reciprocally moving said jaw means in a lateral direc-tion against said article thereby releasing it from said mold section when said mold is open and said mold section is above said discharge opening in said support.

7. The apparatus of claim 6 including jaw means positioned at the bottom of said second mold section and adapted to reciprocally move in combination therewith, and additional means associated with said jaw means of said second mold section for re-ciprocally moving said jaw means in a lateral direction against said article as the mold begins to open thereby maintaining said article within the configuration of the first mold section for movement therewith.

8. A stretch-blow mold apparatus for continuously forming molecularly oriented articles comprising:

a) a plurality of molds each having a pair of par-tible mold sections disposed on a rotatable support and defining a cavity, said support having a discharge opening therein in the vicinity of the cavity of said mold;
b) mold moving means for moving said mold sections between open and closed positions;
c) actuation means synchronizing with said mold moving means with rotation of said support, stretch rod posi-tioning means for each said mold operable in combination with said mold sections moving means and including means to move said stretch rod within said cavity and into and out of said cavity;
d) pressurized fluid means associated with said stretch rod for expanding a workpiece into a formed article; and e) feeding and discharge means to continuously and simultaneously feed preforms to and discharge articles from said mold and including:
(i) plate means positioned above said mold for selectively obstructing passage of a preform to said mold cavity said plate means adapted to reciprocally move in combination with one of said mold sections;
(ii) guide means associated with said plate means and fixedly positioned above said plate means and the center of said cavity so as to retain a preform on said plate means above the center :
of said mold cavity when said mold is closed and until said plate means has moved past the center of said cavity clearing the obstruction;
(iii) retaining means for releasably retaining a formed article in one mold section while said section is moving to open said mold including:

a) an overlay section at the top of said mold section; and b) jaw means positioned at the bottom of said mold section and surrounding one section of the formed article and adapted to re-ciprocally move in combination therewith;
(iv) releasing means associated with said jaw means for reciprocally moving said jaw means in a lateral direction against said article there-by releasing it from said mold section when said mold is open and said mold section is above said discharge opening in said support.

9. The apparatus of claim 8 including jaw means po-sitioned at the bottom of the second mold section and adapted to reciprocally move in combination therewith and additional means associated with said jaw means of said second mold section for reciprocally moving said jaw means in a lateral direction against said article as the mold begins to open thereby maintaining said article within the configuration of the first mold section for movement therewith.

10. The apparatus of claim 9 wherein said stretch rod positioning means include:
(i) first rod positioning means for longitudinally reciprocating a rod while within a cavity of said mold and (ii) second rod positioning means for projecting said rod into said cavity and extracting it therefrom.

11. The apparatus of claim 1 wherein said support workpiece-holder in the vicinity of the cavity of each mold.

12. In the process of blow molding articles from preforms which includes the steps of:

positioning such preforms within cavities of continuously moving and successively presented blow molds;
distending such preforms within the moving molds to form the articles; and discharging the articles from the still-moving molds at an eject station prior to charging with additional preforms;
the improvement in said process which comprises.
holding a preform moving with a moving mold tempo-rarily at each such moving mold while an article is being formed in the cavity of such mold from a prior preform; and charging said preform directly to said mold during or after discharge of an article formed from a prior preform from such mold at the eject station.

13. The process of claim 12 wherein the preform is at orientation temperature during such holding step.

14. The process of claim 12 wherein distending occurs first in the longitudinal and then in the radial direction.

15. In the process of blow molding molec-cularly oriented containers from molded preforms at orientation temperature which includes the steps of:
positioning such preforms within cavities of continuously moving and successively presented blow molds;
distending such preforms within the moving molds to form the articles; and discharging the articles from the still-moving molds at an eject station prior to charging with additional preforms;
the improvement in said process which comprises;
loading individual preforms at a charging station into holders adjacent to and moving with such molds while articles are being formed within such molds from prior preforms;
and charging said preforms while at molecular orientation temperature directly to said molds from such holders during or after discharge of articles formed from prior preforms from such molds at the eject station.

16. The process of claim 15 wherein the prior formed article is being discharged from the mold during charging of such mold with the next preform.

17. The process of claim 15 wherein the charging step is carried out by dropping a preform onto a rod extending upwardly on the axis of the mold cavity.

18. The process of claim 15 wherein said molds traverse a closed circular path during one cycle of the system.