DE2454134A1 - BLOW MOLDING AND STRETCHING PROCESS FOR THE MANUFACTURE OF HOLLOW PLASTIC ARTICLES AND DEVICE FOR CARRYING OUT THE PROCESS - Google Patents

Description

DR-INS. DIPL.-ΙΝβ. M, SC. OIPL.-PHY ». DR. DI »L.- WVI. HÖGER - LEGAL RIGHTS - GRIESSBÄCH - HAECKER PATENT LAWYERS IN STUTTGART

A 40 956 m

a - 123

Nov 13, 1974

Ex-Cell-0 Corporation

2855 Coolidge

Troy, me. 48084, USA

Blow molding and stretching processes for the production of hollow plastic articles and device for carrying out the method

The invention relates to a blow molding and stretching process for producing hollow plastic articles from a heated elongated tubular preform having an open end including a neck portion and a closed end End, the preform being in a plastic state when the blow molding process is carried out, as well as on a device for carrying out the method.

For the manufacture of hollow articles using a blow molding process A variety of blow molding devices and processes have been used from prefabricated preforms. A disadvantage of all known blow molding and stretching processes and devices suitable for this purpose is that the heated prefabricated form, also known as a parcel

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can be and in the following only referred to as a preform is subjected to a considerable cooling and quenching effect due to contact from the mold structure before the stretching or stretching process and the blowing process could be carried out. Such an essential cooling contact occurs at the neck area of the heated preform if it has, for example, a bottle shape; this is the Part of the preform that is the hardest to heat and the fastest to cool. The known blow molding devices also work in such a way that the general mold assembly is closed prior to stretching or stretching the heated preform becomes, which has the disadvantage that the heated preform is then relatively close to the mold structure and this therefore, a significant amount of thermal energy is absorbed by the heated preform due to radiation. This one just mentioned considerable cooling contact of the heated preform through the mold structure and the proximity of the closed mold structure with respect to the heated preform before the stretching or stretching process can be carried out on this premature cooling and uneven cooling of the heated preform; this then leads to uneven Wall thicknesses of the finally stretched and blown article

The invention is therefore based on the task, a method and to provide an apparatus for the manufacture of hollow articles by blow molding and stretching processes with which Can achieve articles of absolutely uniform wall thickness, namely by avoiding premature cooling of the preform can be. Furthermore, there are also special

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designs on the stretch mandrel arrangement are of importance.

To solve this problem, the invention is based on the method mentioned at the beginning and, according to the invention, consists in that

a) the preform is applied to a stretching mandrel with the closed end facing up and

b) the stretching mandrel in a multi-part, consisting of a pair of mold halves, a mold end insert and a pair of clamping rings existing molding device is introduced that

c) the two clamping rings in a clamping connection with the brought open neck part of the preform and

d) the stretching mandrel is operated so that in the open position of the mold halves, the preform is stretched to a predetermined length that

e) brought the mold halves together with the mold end insert into the closed position by closing and

f) blowing air under pressure is introduced through the stretching mandrel into the preform and the preform is in contact with the mold is brought with the multi-part molding device.

A device for carrying out this method is possible from a device for blow molding and stretch molding for the production of hollow plastic articles from a heated elongated tubular preform and consists of a pair between an open and a closed position moveable mold halves, a mold end insert and a pair of also between open and closed positions movable clamping rings are provided, which during a

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stretching or stretching of the preform and before the mold halves can be moved into their closed position, as well as during the blow molding of the preform and the cooling process, after the mold halves are moved to the closed position, hold the preform between the mold halves.

Generally speaking, the invention encompasses the arrangement of a tubular preform with one closed and one open End on a stretching mandrel in such a way that the closed end is at the top, then the stretching mandrel Introduced into a multi-part molding device, each consisting of two mold halves, two clamping or tension rings and one upper mold end insert is formed. The clamping rings initially move into a clamping connection with the neck part of the preform, which extends adjacent the closed end of the preform; then the stretching mandrel assembly is operated in such a way that that the preform is stretched to a predetermined length the mold halves are in the open position. After the stretching process or the stretching process, the mold halves are closed and it is fed into the preform over the stretch mandrel assembly Pressurized blown air is introduced, which makes it possible to keep the preform in normal mold contact with the now closed Bring molding device. The mold halves, the mold end insert and the clamping rings for the neck part are operated in such a way that that the neck portion of the preform is clamped and the preform is stretched before the mold halves themselves are closed, so that premature cooling of the preform before the blowing process is avoided.

The tubular preform from which the final hollow articles will ultimately be blow molded is

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while being axially oriented in the multi-part molding device and is located between the two open mold halves for the initial implementation of the stretching process before closing the mold halves themselves.

The preform is subjected to the blow molding process in the plastic state, the heated preform first being applied to the Stretching mandrel is applied and this is then moved into the multi-part molding device; the molding device consists it consists of a pair of molded parts, a pair of clamping or retaining rings and a mold end insert. First, the retaining rings were clamped to the neck portion at the closed end brought the preform, then the stretching mandrel is actuated to stretch the preform to a predetermined length, the Mold halves are in an open position, eventually the mold halves together with the end insert or the mold end insert is closed and pressurized blowing air is passed through the stretching mandrel assembly into the preform introduced. The mold halves can during the time at which the clamping rings with the neck portion of the preform be brought into a clamp connection, moved from a fully open position to a partially open position will. The stretching mandrel is operated in such a way that it extends and expands the preform to a predetermined length until the closed end of the preform is the mold end insert touches or engages when that mold end insert is either in the normal mold position or, even if the end of the mold is initially after has been moved inside the mold halves; in this Case, the stretching process of the preform is continued,

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until the end mold insert has moved out of the two mold halves into its original mold position. Captured thereby then the closed end of the preform has the mold end insert in the molding position without any being exercised by the preform Pressure, and the blowing process is carried out.

Further refinements of the invention are the subject of the subclaims and laid down in these.

The method according to the invention and the structure and mode of operation of exemplary embodiments of the invention are illustrated below of the figures explained in more detail. Show:

Figure 1 is a plan view of a five-part molding device,

FIG. 2 is an enlarged side sectional view of the molding device of FIG. 1 along the line 2-2 with the stretching mandrel positioned within the mold halves in a starting position for the entire stretch-blow molding process,

Figure 3 is a representation similar to Figure 2,

wherein the mold halves are closed in the manner and the upper mold end insert around a relative A short distance inward is introduced into the mold halves, and the preform is also clamped between the clamping rings and stretched so far that they on the mold end insert has occurred

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FIG. 3 A shows a modified side view in detail in a sectional side view Embodiment of a clamping ring and a stretching mandrel arrangement as a counter bearing to hold the preform,

FIG. 4 is a view similar to FIG. 3 with the mold end insert withdrawn, the is in the normal blowing position suitable for blowing a bottle; the preform has been stretched to the position at which the blowing process will now take place begins

Figure 5 is a view similar to Figure 4, after the two mold halves in the closed position and before air into the preform for the blowing process has been introduced

Figure 6 corresponds to Figure 5, but after the blowing process,

FIG. 7 shows, in a side view and partially in section, the stretching mandrel arrangement which can be used in conjunction with the molding device,

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Figure 8 shows the stretch mandrel device of

Figure 7 in a horizontal view and partially in section, namely along the line 8-8 in Figure 7,

FIG. 9 shows the general actuating device in side view and partially in section for the mandrel arrangements of Figures 7 and 8,

FIG. 10 corresponds approximately to FIG. 1 and shows

the lateral removal movement of the blown bottle from the opened mold halves, while

Figure 11 is a plan view of a further embodiment shows a five-part molding device, with the movement of the individual parts other movement arrangements of the molding device, which do not carry out an opening pivoting movement, but a lateral transversal movement, are provided.

The present blow molding process and the corresponding, for Implementing this process certain blow molding machines are designed to be used in the production of articles Plastic, for example bottles and the like., And preferably from_thermoplastischem plastic can serve. The preforms, i.e. the tubular blanks that make up the final article

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ultimately to be made can be made of any thermoplastic synthetic resin, such as polymers and copolymers of polypropylene. The synthetic resin can be extruded or otherwise into the Preforms have been cast, molded or injected; these preforms, as they are merely referred to below are then fed to the blow molding machine of the present invention with the aid of suitable arrangements.

In this connection it should be noted that the devices and systems for forming the preforms and for heating and conveying the preforms to the molding machine herein Invention are not part of the invention, any apparatus and devices suitable for this purpose can be used. As can be seen from FIG. 2, the reference numeral 10 generally denotes the preform which essentially has the shape of a test tube or the like. The elongated tubular ones used in the invention Preforms 10 have a closed end and an open end, around which a designated by the reference numeral 10 Thread is formed. As can also be seen from FIG. 2, the preforms 10, which are generally also referred to as Parcels can be designated, suitable expansion mandrels 12 loaded, which convey the preforms 10 into the molding device according to the invention, so that there is a stretching and blow molding process can be made.

As can be seen in FIGS. 1 to 6, the invention comprises Molding device a five-part mold, which consists of a pair of side parts or mold halves 13, a mold end

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set 14 and a pair of neck rings or clamping parts 15 consists. Figure 2 also shows that each mold half 13 has a cavity 16, in each of which an article, in this case a bottle, for example, is given its final shape by placing it on the interior walls of the cavity. The mold halves 13 are semicircular in their cross-section, each has a semicircular at its upper end central opening 17, which is generally in communication with the cavity 16 stands and in which the mold end insert or the bottom cover 16 is effectively received. Here is the inner surface 18 of mold end insert 14 of such a shape that that the bottom of the bottle can be shaped.

The two mold halves 13, the mold end insert 14 and the clamping parts 15 can be cooled by suitable arrangements, for example by means of cooling water which flows through suitable cooling lines in the mold parts, with a suitable coolant supply source also being provided which presses the coolant through the lines. Suitable coolant passage arrangements are described in more detail in an application dated the same day (our file A 40 941 m) entitled "Blow molding machine", to which reference is made in this context. The description of these cooling passage arrangements can be found in these patent applications in FIGS. 2, 27 , 28, 31 , 35, 39 and 42 as well as the description relating to them.

The mold halves 13 and the clamping rings 15, as they are in the following are only to be referred to, between the open position shown in Figures 1 and 2 and the in the closed positions shown in Figures 5 and 6 through

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suitable devices are moved, for example by being mounted pivotably on individual mold carriers are generally designated by the reference number 19 in FIG are. The mold carriers 19 are pivotably mounted on a mold carrier shaft 20 and can be made by suitable means can be moved between the open and closed positions. Such suitable mold carriers are already in the just now mentioned parallel application, in particular in Figures 4, 21, 22, 28-33, 36, 38 and 39 and the associated parts of the description.

As can be seen in FIGS. 1 to 6, the mold end insert is 14 effectively with the lower end of a bearing shaft 24 connected. Two arc-shaped brackets for the mold end insert are designed so that they can be used during the Blow molding process in a clamping position around the bearing shaft are movable to the mold end insert 14 in the figures and 6 to position the special mold position shown in a form-fitting manner. The brackets 25 exist for the mold end insert made of clamping plates which are fastened to the upper parts of the two mold halves 13 with the aid of suitable screw connections. Therefore, the clamps 25 for the mold end insert are moved into their clamping action connection with the end insert 14 when the mold halves 13 also move into the closed position. -

It goes without saying that when the stretching mandrel encompasses Arrangement 12 moved into an operative connection between the two mold halves 13, this in axial alignment with the mold end insert 14 happens. As explained in more detail below

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is refined, the preform 10 can be stretched or stretched until it reaches the lower end portion 18 of the mold end insert 14 has, either when the mold end set 14 is in the molding position of Figure 5 or in an axially inwardly pushed position Position in relation to the two halves of the mold, as shown in FIG. IM the mold end insert 14 between the inner position shown in FIG and the mold position of Figure 5, suitable movement arrangements may be provided. As Figure 3 shows, can for example a cylinder which is actuated by a suitable pressure medium and which is generally designated by the reference number 27 is to be operatively connected to the bearing shaft 24 for the mold end insert that the mold end insert 14 is between the inner position of Figure 3 and the mold position of Figure 5 can move.

Other means serving to move the mold end insert 14 between the two positions include those already mentioned Parallel registration on Figures 2, 21, 22, 39, 41, 42, 53, 57 and 58 as well as the corresponding description.

In the case of the vibratory bearing structure for the molding device In the present invention, the clamping rings 15 are also carried by separate clamping ring carriers 28, as FIG. 1 shows. The clamping ring carriers 28 are each rotatably mounted on the bearing shaft 20. The clamping ring carriers 28 are grounded in the process pivoted between the open position of Figure 2 and the closed position of Figure 3 by suitable means, in that they are pivoted inward and outward with the movement of the mold half-carrier 19.

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As FIG. 1 shows, the mold half-carriers 19 with the clamping ring carriers 28 connected by means of suitable spring assemblies 29 which work in such a way that they the clamping ring carrier

28 with respect to the inner peripheral edges of the mold halves 13 preload inwardly in order to enable the clamping rings 15 to clamp a preform 10, as shown in FIG. 3, when the mold halves are in an only partially closed position.

As the first embodiment of Figure 2 shows, each clamping ring 15 is provided with an arcuate recess 30, the inner surface of which is designed to match the turns 11 on the preform 10 when the Clamping rings 15 in their shown in Figures 3 to 6. Clamping position move. Each spring arrangement 29 is assigned a pocket in the respective mold half-carrier 19, in which a suitable spring 21 is mounted, the outer end of which is in adjacent contact with the associated clamping ring carrier 28 is located so that it is normally biased forward with respect to the associated mold half 13.

These clamping ring carriers and spring preload arrangements 28,

29 are detailed in the parallel application already mentioned repeatedly (our file A 40 941 m), specifically described in Figures 27, 28 and 35 with the associated description.

In Figure 3A, a modified embodiment is shown with a modified clamping ring 15a, which has a has arcuate recess 30a, which the windings 11 the preform takes up. This modified recess 30a is bounded by an upper shoulder 15a, which with a school

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ter 11a in operative connection in the area of the thread 11 of the preform occurs and thereby holds the preform during the stretching process and during the stretching and blowing process on the Preform exerts a sealing pressure. The recess 30a is also limited by a lower shoulder 15c, which the Detected end region or the threaded end of the preform 10 in order to also exert a sealing pressure and expansion on this to prevent this end region of the thread during the blowing process. To seal with the end of the thread 11 of the In the preform 10, an O-ring 53a is also inserted in operative connection with the flange surface 53.

It goes without saying, moreover, that the mold halves 13, the mold end insert 14 and the clamping rings 15 between their open and closed positions also by devices other than the pivoting systems described can be moved. In Figure 11 is for example in a schematic representation a modified embodiment is shown from which it can be seen how the multi-part molded parts laterally between open and closed positions by other suitable means, for example by a variety of means can be moved by means of a pressure medium actuated working cylinder. It can be seen more precisely from FIG. 11 that the mold halves 13 can be moved towards and away from each other with the help of a pair more suitable, of one Pressure medium actuated working cylinder 34. The same movements perform the clamping rings 15, including a pair of working cylinders 35 is provided. Finally, the clamps 25 for the mold end insert are between their opened and hers

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closed position of a pair of suitable, actuated by a pressure medium working cylinders movable. The movement of the end mold insert 14 takes place dab.ei in the manner already described above, also with the help of one of a Pressure medium actuated working cylinder 37. Also the movement of the stretching mandrel arrangement 12 for the introduction of a preform 10 into a working position in the multi-part molding device and for removal of the same takes place with the aid of a suitable Working cylinder 38.

The stretch mandrel assembly 12 can be of any suitable type Be build. In Figures 7 and 8, a stretching mandrel assembly 12 is shown, which is used to carry out the inventive Measure can serve. In general, it can be stated that the stretching rod arrangement 12 is out of the position shown in FIG can be moved into the working position between the two mold halves 13 by any conveyor structure, wherein the mandrel assembly is moved to an axially aligned position with the mold end insert.

As Figure 7 shows, the stretching mandrel assembly 12 includes a main body 39 through which a longitudinally slidable mounted stretching mandrel 40 extends. The upper end of the stretching mandrel 40 is slidable in a longitudinal bore 41 a Air nozzle 42 mounted, which also serves as a bearing bush for this upper end of the stretching mandrel 40. The lower end of the stretch mandrel 40 is slidably mounted in a bore 43 which is drilled longitudinally through a suitable sleeve 44 which in turn into a threaded opening 45 in the lower part of the tubular main body 39

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is screwed. The sleeve 44 is adjustable in the longitudinal direction in the main body 39 with the aid of a suitable nut 46 secured and braced. On the stretch form 40 is a one-piece Stop flange 49 molded to a downward and limit movement of the stretching mandrel 40 in the main body 39 due to the influence of gravity.

Furthermore, the stretching mandrel 40 has at its lower end via a cam block 50 and is thereby formed so that the cam block or cam follower is of a suitable cam arrangement detected and thereby the stretching mandrel 40 is moved so far down in the main body 39 until the stop flange 49 reaches the top of the sleeve 44. From this it can be seen that the initial lowered or starting position ι of the stretching mandrel 40 is determined by the position of the stop 49 on the stretching mandrel 40 in connection with the relative position the sleeve 44 in the main body 39.

In this regard, it should be understood that the multi-part molding apparatus of the present invention can be used by many as a single piece or in an arrangement. The representations of FIGS. 7 and 8 show the use of the molding apparatus of the present invention on a molding machine having a variety of such molding apparatus having.

As can be seen from the illustration in FIG. 7, the upper end of the air nozzle 42 extends outward the upper end portion of the main body 39; the air nozzle 42 is here provided with a conical upper end surface 51, as a sleeve for guiding an inverted preform

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serves down over the upper end of the stretching mandrel 40 when the stretching mandrel 40 is provided with a preform. The conical upper end surface 51 of the air nozzle 42 terminates at its lower part into a radial flange 52 which limits downward movement of the air nozzle 42 in the main body 39. The upper Surface 53 of radial flange 52 forms a support or seat for the open threaded portion of preform 10.

As can be seen in FIG. 7, the air nozzle 42 is provided for sliding sealing connection with the outer surface of the Stretching mandrel 40 has a suitable seal 54 mounted in an effective manner. Furthermore, in the illustration of FIG. 7, a so-called hairpin holding and locking device is denoted by the reference numeral 55, which detachably connects the air nozzle 42 in theirs. Position in the upper end of the main body 39 secures. This hairpin retainer 55 consists of a straight one Leg part 56 which is designed so that it fits through an opening or a bore 57 (Figure 7) which is formed itself is made up of a pair of arcuate recesses that are horizontally aligned with one another on the one hand on the outer surface of the air nozzle 42 and, on the other hand, are formed on the inner surface of the main body 39. This hairpin fuse 55 also has a curved leg region 57, which is in an outer arcuate peripheral Recess 58, which is formed on the outer circumference of the main body 39, comes to rest and finds a seat there.

It can also be seen from FIG. 7 that at the lower end of the stretching mandrel 40 with the aid of a suitable screw 61 a cylindrical block 59 together with the block 50 and Washer 60 is attached. The cylindrical block 59

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acts as a stop element and device, with the lower end 62 the sleeve 44 in operative connection. The distance between the upper end of the stop block 59 and the lower end 62 of the Bushing 44 defines the entire travel range of the stretching mandrel 40 to be covered upwards, which the stretching mandrel 40 enters into the preform 10 to carry out a stretching process. In one embodiment of the invention, this path length is approximately 10.2 cm.

As can be seen from the representations of FIGS. 7 and 8, the upper end of the air nozzle 42 is enlarged to form a Bore 65 enlarged so that one arrives at an annular passage 66, the supply of blown air into the Preform 10 is used so that it can be blown into a finished article, namely the one in FIGS. 6 and 10 the bottle provided with the reference numeral 67. As Figure 7 shows, the lower end of the annular passage 66 is four Cross bores 69 in connections, which in turn are connected to a second outer annular passage area 69 which, as can also be seen from FIG. 7, opens into an opening 70 which opens in the side wall of the main body 69 and finally merges into a passage 71 which is formed in a fitting 72. Of the Fitting 72 is positioned around passage 61 with suitable sealing means so as to form a tight connection with the main body 39 is possible. The fitting 72 is designed so that it is able to use a suitable supply source Blown air to be supplied.

Finally, the stretching mandrel 40 is designed in such a way that the so-called "ejection air" can be supplied, which is shown in FIG

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the effect that a finished bottle 67 is removed from the stretching mandrel 40 can eventually be ejected. To this end, it can be seen from FIG. 7 that the main body 39 has an inlet opening 73 for the discharge air has, this inlet port 73 is with a enlarged bore 74 in the main body 39 in connection, through which the stretching mandrel 40 runs. Ejection air will therefore the inlet port 73 is supplied and passes into the bore 74 and from there down and finally through four transverse bores 75 in the stretching mandrel 40 in an axial passage 76 in this. Period. The ejection air then flows through the axial passage upwards, a check valve 77 happens, which when Ausfüh-. approximately example is designed as a ball check valve, and flows through four upwardly inclined or beveled shaped passages 78 and into the finished article 67, thus this can be ejected from the stretching mandrel 40 under the effect of the ejection air. It should be noted that the Passages 78 have an inner inclined surface, the inclination of which with respect to the center line of the stretching mandrel 40 is approximately 9 is. The check valve 77 prevents blown air from flowing outward through the axial passage 76 during the blow molding process in making the article. As shown in FIGS. 7 and 8, the stretching mandrel assembly 12 can be moved and driven by any suitable means will; so it is possible to effectively mount the stretch mandrel arrangement on a carrier chain, the chains * - having connecting plates 81 and 82 which are operatively connected with the aid of suitable bearing pins 83 and split pins 84.

Figures 4, 5 and 6 show a stretching mandrel 40 in the fully extended position for performing a blow molding process.

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FIG. 7 shows the stretching mandrel 40 in the starting position or lowered position for receiving a new preform and moving it into the one of several individual parts existing molding apparatus of the present invention. The stretching mandrel 40 can be actuated from the initially lowered position Position of FIG. 7 by any system; a suitable actuator is shown in FIG. The one in Figure 9 The actuator shown consists of a spring pressure arrangement, which is designed so that it the lower side of the block 50 of the stretching mandrel 40, as in Figures 7 and shown, recorded. For this purpose, the spring pressure arrangement consists of a cylindrical lifting block 85, which in its interior with a stepped bore is provided, which is composed of the individual bores 86 and 87. Within the larger The head 88 of a shaft 89 is slidably mounted in the bore 86. The shaft 89 also slidably extends downward through the smaller bore 87 and is mounted with its lower end in a suitable bore of a support rod 90. For this purpose, the lower end of the shaft 89 can be secured with the aid of a suitable locking means 91. Between the The upper surface of the support rod 90 and the lower surface of the lift block 85, surrounding the shaft 89, is a coil spring 92 mounted. The lifting block 85 is therefore arranged vertically movable on the shaft, the spring 92 for a adjustable, upward spring pressure or a corresponding bias on the stretching mandrel 40 ensures. This spring pressure arrangement Compensates for possible misalignments and tolerances in the original assembly and alignment of the actuator.

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As can be seen from FIG. 9, the support rod is fixedly connected, for example by welding, to a further carrier cam rod 95. This carrier cam rod 95 is also, for example by welding, with a pair of vertically spaced horizontal crosspieces 96 and 97 connected. Each of these crosspieces 96 and 97 is slidable on a pair of vertically and laterally Sliding shafts 98 held at a distance from one another are supported. The upper ends of the sliding shafts 98 are fixed to a mounting plate 99 connected. The mounting plate 99 is in turn on a bearing structure 100 with the aid of suitable means attached to which the molding device is also mounted. The lower ends of the sliding shafts 98 are suitable connected to a plate 101. Finally, as can be seen from FIG. 9 in this context, there is another Cam follower 102, namely a roller, rotatable with the lower one End of the carrier cam rod 95 connected. The cross pieces 96 and 97 and the carrier cam rod 95 form a carriage or a slide assembly comprising the cam follower 102 and the further above mentioned spring pressure arrangement for lifting the stretching mandrel 40 is supported.

Furthermore, the illustration in FIG. 9 also includes a spring-loaded one Locking arrangement, which is indicated generally by the reference numeral 104 and which is formed., that it is able to releasably hold a stretching mandrel 40 in the blow molding position shown in FIG. In the illustration of FIG. 9, the locking arrangement is shown 104 shown in the way they are currently actuating the cam-controlled and stretching mandrels-

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the sliding guide structure solves and so a downward one Movement of the stretching mandrel 40 back into the starting position shown in Figure 7 is enabled. The locking arrangement consists initially of a stop plate 105, the other one at the bottom Side of the upper crosspiece is mounted horizontally using a pair of suitable screws 106 and washers 107 is. The washers 107 allow the stop plate 105 to be adjusted up or down to a desired one Position so as to reduce the pressure of the spring 92 on the stretching mandrel 40 to control. As Figure 9 shows, the underside of the stop plate 105 is formed so that it is from the upper end a pivotably mounted locking element 109 can be detected.

The locking element 109 is suitable for this purpose Manner attached to a horizontal pivot pin 110, which in turn is pivotable between a pair of vertical and laterally spaced-apart bearing plates 111 is stored. The lower ends of these bearing plates 111 are, for example, by welding to the plate 101 and the upper ends attached to plate 99 by welding. The pivot pin 110 is pivotably held in suitable bearings, with the help of a pair of journal bearings 112, which are attached to the inner sides of the plates 111. As can be seen in Figure 9, the locking member 109 is normally biased clockwise to be bring top end 108 under stop plate 105; the preload is carried out with the aid of a suitable helical spring 115, which are functionally of a pair of mutually aligned, spaced support rods 160 is held.

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One of these retaining rods 116 assigned to the spring 115 is shown in FIG a suitable bore in the rear upper surface of the locking element 109, while the other Holding rod 116 in a suitable bore of a vertical Haltepiatte 117 is attached, which in turn firmly between the two vertical bearing plates 111 is held.

As can be seen in FIG. 9, the clockwise direction extending movement of the locking element 109 is limited by a stop consisting of a threaded provided rod 118, which is supported by the retaining plate 117 screwed and in an adjustable position by a lock nut 119 is secured. With the lower end of the locking element 109 is a cam follower, for example in the form of a roller 120 connected in such a way that the locking element , as can be seen from FIG. 9, for release the slide guide structure can be cam rotated in a counterclockwise direction.

The locking element holds during the blow molding process the slide bearing the spring pressure arrangement for the stretching mandrel, leadership structure in the raised position. The dash-dotted representation of FIG. 9 shows that furthermore a horizontal cam structure 121 is operatively connected to the bearing structure 100 of the machine, to actuate the cam follower 120 at coordinated desired intervals during a blow molding process. The cam follower 120 and the associated sliding guide structure and the correspondingly actuated spring pressure arrangement for the The expansion mandrel can then be added to another suitable cam structure of the overall bearing system at the required time intervals.

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move structure 100 up. It goes without saying that for Implementation of the measures according to the invention any stretching mandrel assembly 12 and lifting and actuating systems are used can be. In this context, reference is again made to the explanation of stretching mandrel arrangements and lifting and actuating systems as detailed in Parallel applications already mentioned above in FIGS. 2-6, 8 to 10 and 13-16, 21-24, 29 and 45-52 and are explained in the associated description.

To carry out the method according to the invention, the Stretching mandrel assembly 12 is inserted into the split mold apparatus in a position that is in vertical orientation to the mold end insert 14 as shown in FIG. The mold end insert can also be selectively moved into the interior of the mold halves 13 in the position shown in FIG introduce. The assemblies for moving the mold halves 13 and the clamping rings 15 are then operated to close the clamping rings 15 in a clamping engagement position with that with a thread to bring provided neck region 11 of the preform 10, as shown in FIG. Are like this ahead has already been described, the clamping rings 15 in one embodiment present invention carried by the mold halves, then the mold halves 13 move out of the fully open position of Figure 2 in the partially open position of Figure 3. It can be seen that in the position of Figure 3, the threaded end portion 11 of the preform 10 for performing a stretching process is firmly clamped in place, but there is still no contact between the preform 10 and the mold halves 13, so

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that the preform 10 is not cooled or quenched, before it has been stretched. The preform is therefore due to a contact or a connection with the multi-part Molding device not cooled with the exception of the threaded neck portion 11 thereof. This just described mode of operation of the mold structure leads to a finished article that has a more uniform wall thickness, due to the fact that each cooling contact of the preform 10 by the mold structure, apart from the neck region 11 during the stretching process of the preform is.

The stretching mandrel assembly 12 is then actuated to move the stretching mandrel 40 inwardly into the mold halves 13, so that the preform 10 is stretched or stretched until it reaches the lower end 18 of the mold end insert 14, as shown in FIG is. The mold end insert 14 is then, as can be seen from FIGS. 3 and 4, upwards into the blow molding position Figure 4 moves. At the same time, the stretching mandrel also moves further upwards in order to continue the stretching process of the preform 10, and to hold the upper end of the stretch mold 10 in contact with the lower end 18 of the mold end insert 14. These simultaneous upward movement of the mold end insert 14 and the stretching mandrel 40 continues until the mold end insert 14 has reached the molding position of FIG. Then the two mold halves 13 move inwards into the closed one Position of FIG. 5 and the stretching mandrel arrangement 12 is supplied with blown air. This blown air causes the preform 1O outwards into the mold halves 13 for the formation and shaping of the End product 67 is blown. After a given time

509820/1063

a - 123

Nov. 13, 1974 - Nov. 26

interval is then the molding device in the in Figure 10 The open position shown is moved, the mold end insert 14 is used to release the pressed-in middle part of the mold insert is withdrawn and the stretching mandrel assembly with the finished article 67 is removed from the molding apparatus moved into a position at which the ejection air can then be fed to the stretching mandrel assembly 12 to produce the finished Article 67 to blow away from the stretching mandrel 40.

It will be understood that this molding process can also be performed without the mold end insert 14 inwardly into the The position shown in Figure 3 must be moved with respect to the two mold halves 13, i.e. the mold end insert is moved only in the blow molding position of Figure 4. Alternatively, it is therefore possible to use the mold end insert 14 in the To hold the mold position of Figure 4 and the preform 10 in a single, continuous stretching process in connection with this To bring mold end insert 14 into its mold position.

Another possible workflow would be that the mold end insert 14 inwardly into the two mold halves 13 up to one Position is brought into contact with the preform 10 and the stretching mandrel 40 when both are still in their starting position of Figure 2 are located. The stretching mandrel 40 then moves inwardly into the mold halves 13 and stretches and stretches the preform 10 and at the same time lifts the mold end insert 14 into the mold position of FIG. 4.

The preform 10 becomes the mold end insert 14 without exerting any excess pressure on the latter during the blow molding process

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Nov 13, 1974 - 27 -

of Figures 4, 5 and 6 held in a contact connection. Indeed, the overpressure exerted by the spring 92 is generated by the contact between the block 59 and the sleeve 62 is absorbed and transmitted via the main body 39 and sleeve 52 in such a manner that the shoulder 53 causes the air nozzle will apply to the captured neck portion of the preform and create a seal for the blow molding process.

The lifting and actuation structure already explained above for the stretching mandrel it enables that shown in FIG Actuating member for the stretching mandrel, when it is in its fully extended position, by a slight To slide down a distance, for example by about 1.6 mm, so as to each from the block 50 of the extensor dome remove mechanical pressure without the contact between the upper end of the stretched preform and the mold insert 14 is lost or without a drop in the sealing pressure. The control of this pressure on the stretched preform and against the mold end insert 14 is carried out by setting and checking the above-mentioned cam configurations, Washers, lock adjustment and spring pressure. By correct adjustment of the washers 107 and the position of the lower end 62 of the sleeve 44 can be the pressure of the stretching mandrel 40 on the stretched preform and against the Check mold end insert 14 in such a way that the contact between these two parts, namely the stretched or stretched preform and the end mold insert 14, there is only one touch contact is without any overpressure.

50 98 20/1063

Claims (1)

Patent claims: Blow molding and stretching processes for the manufacture of hollow Plastic articles made from a heated elongated tubular preform having an open including a neck portion End and a closed end, the preform being in a plastic shape when the blow molding process is carried out Condition is characterized by that a) the preform is applied to a stretching mandrel with the closed end facing up and b) the stretching mandrel in a multi-part, consisting of a pair of mold halves, a mold end insert and a pair of clamping rings existing molding device is introduced that c) the two clamping rings in a clamping connection with the brought open neck part of the preform and d) the stretching mandrel is actuated in such a way that when the mold halves are in the open position, the preform is cut to a predetermined length that is stretched e) the mold halves together with the mold end insert through ~ Closing brought to the closed position and f) blowing air under pressure is introduced through the stretching mandrel into the preform and the preform is in contact with the mold is brought with the multi-part molding device. 509820/1063 a - 123 Nov 13, 1974 -Sr- 2. The method according to claim 1, characterized in that when the clamping rings are brought into a clamping connection with the neck part of the molding device, the mold halves are moved from the open position to a partially open position. 3. The method according to claim 1 or 2, characterized in that that the preform is stretched to a predetermined length by extending the stretching mandrel until the closed end the preform engages the mold end insert located in the molding position. 4. The method according to any one of claims 1 to 3, characterized in that that the closed end detects the Formendeinsatζ located in the molding position without during of the following blowing process, a pressure is exerted by this on the mold end insert. 5. The method according to any one of claims 1 to 4, characterized in that that the mold end insert from a mold position with respect to the mold halves in a predetermined, the preform Detecting position is moved inward, that the stretching mandrel is actuated to stretch the preform until the closed end of the preform abuts the mold end insert in the lower position and that the extension of the stretching mandrel to stretch the preform to a predetermined length is continued with simultaneous movement of the mold end insert outwards from the mold halves into the mold position. 509820/1063 a - 123 Nov. 13, 1974 «8 · 6. The method according to any one of claims 1 to 5, characterized in that that by introducing ejection air through the stretch mandrel after the molding process, a finished article from Stretching mandrel is thrown off. 7. Device for blow molding and stretch molding for the production of hollow plastic articles from a heated elongated tubular preform for carrying out the method according to one or more of claims 1 to 6, characterized in that that a pair of mold halves (13) movable between an open and a closed position, a mold end insert (14) and a pair of clamping rings (15) also movable between an open and closed position are provided during a stretching or stretching process exerted on the preform (10) and before the mold halves (13) are movable into their closed position, as well as during blow molding of the preform and the cooling process, after the mold halves (13) are moved to the closed position, hold the preform between the mold halves. 8. The device according to claim 1, characterized in that between the two clamping rings (15) one between a preform receiving. Position and a blow molding position movable stretching mandrel assembly (12) is provided, which the preform (10) in axial alignment with the mold end insert (14) and in position between the mold halves (13) during . that keeps stretching, Rias and cooling processes. 509820/1063 A 40 956 m a - 123 Nov. 13, 1974 -M- 9. Apparatus according to claim 7 or 8, characterized-characterized, that the stretching mandrel assembly (12) has a tubular main body (39) and a stretching mandrel slidably mounted in this (40) and a guide bushing (42, 51, 52) mounted on the main body (39) for guiding the stretching mandrel (40) during a stretching process and for receiving and holding a preform in the working position in which the neck part (11) the preform (10) from the clamping rings (15) during the stretching, blowing and cooling process can be detected. 10. Device according to one of claims 7 to 9, characterized in that that the clamping rings (15) movement and bearing arrangements (28, 34) are assigned to these in a clamping connection to bring with the neck part (11) of the preform (10) held on the stretching mandrel arrangement (12), such that the The preform can then be clamped between the mold halves (13) and stretchable by the stretching mandrel (40) when the mold halves are at least in a half-open position. 11. Device according to one of claims 7 to 1.0, characterized in that that each clamping ring (15) is movable in such a way with one of the mold halves (13) for carrying out a Movement is associated with these that the neck part (11) the preform on the Dornstreckanoicdnung (12) before closing the mold halves (13) can be detected. 50 9 820/1063 a - 123 Nov 13, 1974 - 12. The device according to claim 11, characterized in that that the arrangement connecting the clamping rings (15) to one of the mold halves (13) is a spring preload arrangement (29) includes. 13. Device according to one of claims 7 to 12, characterized characterized in that the main body (39) for conveying blown air into the preform held on the stretching mandrel (10) has passages (71, 70 * 69, 68, 66, 65). 13. Device according to one of claims 7 to 13, characterized in that the stretching mandrel (40) is assigned an actuating device (85, 89, 92, 90, 95, 96, 97) in order to stretch the clamped preform (10). to lead into the interior of the mold halves (13). 15. Device according to one of claims 7 to 14, characterized characterized in that the mold end insert (14) in axial Alignment to the stretching mandrel (40) is arranged to during the stretching process of the preform. {ΊΟ) and to control a predetermined stretching length to come into operative connection with this. 16. Device according to one of claims 8 to 15, characterized in that that an arrangement (27) for moving the mold end insert (14) between a mold position and a the engagement position with the preform (10) located within the two mold halves (13) is provided, such that the mold end insert (14) at least during part of the stretching process of the preform (10) with this is in connection. 509820/1063 Nov. 13, 1974 «β * - 17. Device according to one of claims 1 to 16, characterized characterized in that movement and bearing arrangements (19,35) are provided for the two mold halves (13). 18. Device according to one of claims 7 to 17, characterized characterized in that one of the mold halves (13) is carried for clamping the mold end insert (14) in the mold position Clamping arrangement (25) is provided. 509820/1063