DE102006062893B3 - Device for the production of band-shaped plastic preforms - Google Patents

Abstract

Molding device for the production of band-shaped plastic preforms, comprising an extrusion head (3) and a molding tool connected at least indirectly to the extrusion head (3) and having a plurality of channels (26), each of which has an inlet opening (27) in the form of a segment of a ring and an elongate outlet opening (28), wherein the inlet openings (27) in the form of ring sections are arranged distributed over the circumference on a common radius and are separated from one another by radially running cutting edges (49), and an adapter element (4) is arranged between the extrusion head (3) and the molding tool (5), which has a the annular outlet opening of the extrusion head (3) and an outlet opening (28) coinciding with the annular section-shaped inlet openings (27) of the mold (5), the extrusion head (3) having an annular housing (7) with an inner bore (8), a central sleeve (9) with a peripheral outer surface (10), and a ring part (11) radially between the inner bore (8) and the peripheral outer surface (10), the adapter element (4) being arranged below the extrusion head (3), and wherein the adapter element (4) has an outer ring part (16) connected to the ring-shaped housing (7), a cylindrical inner part (17) connected to the central sleeve (9) and an inner part (18) in the shape of a truncated cone that can move axially relative to this.

Description

The invention relates to a device for producing band-shaped plastic preforms from a tubular preform. Such band-shaped preforms can then be further processed individually according to the intended use.

From the DE 102 31 866 A1 a multi-stage process and a device for the production of hollow bodies from plastic half-shells is known. For this purpose, a tubular plastic preform emerging from an extrusion device is divided by means of a cutting device. The cutter has a triangular cross-section and is positioned perpendicular to the direction of extrusion. Two driven drive rollers are arranged in the immediate vicinity of the cutting device, which exert a tensile force on the semi-finished panels. Two half-shells are then formed from the semi-finished panels, which are connected to one another along a peripheral edge in order to form the hollow body.

Another method for producing hollow bodies, in particular for plastic tanks, from an extruded tubular preform is known from US 2001/0 015 513 A1. For this purpose, the tubular preform is divided into two bands by means of a knife after exiting the extrusion head. The tapes are conveyed to a forming tool by means of rollers. A nozzle is positioned between the two belts, through which air is blown into the tool. In this way, the plastic hollow body is formed.

From the DE 103 55 818 A1 an extrusion die with wall thickness control is known. For this purpose, one or more slides are installed in the nozzle mouthpiece, which is attached to the housing of the compression head by means of a retaining ring.

From the EP 1 661 687 A1 discloses an extrusion head for producing a tubular preform that has a pivotable die head for adjusting the gap. The DE 31 17 179 A1 describes a method for producing band-shaped plastic preforms. From the DE 24 29 008 A1 the division of a full strand into two strip-shaped profiles is known. In the "Handbook of Plastic Extrusion Technology" (Hensen, Knappe, Potente; ed.; 1st edition; Publisher: Hanser; 1989) adapters for extrusion blow molding machines are described.

The present invention is based on the object of proposing a molding device for the production of band-shaped plastic preforms which ensures favorable deformation and flow behavior and enables a homogeneous layer distribution over the width of the preforms.

The above-mentioned problem is solved by a molding device for producing band-shaped plastic preforms, comprising an extrusion head and a molding tool connected at least indirectly to the extrusion head and having a plurality of channels, each of which has an inlet opening in the form of a segment of a ring and an elongated outlet opening, with the inlet openings in the form of a segment of a ring being located on a common radius distributed over the circumference and are separated from each other by radial cutting edges and wherein
an adapter element is arranged between the extrusion head and the molding tool, which has an inlet opening that matches the annular outlet opening of the extrusion head and an outlet opening that matches the annular section-shaped inlet openings of the molding tool,
wherein the extrusion head has an annular housing with an inner bore, a central sleeve with a circumferential outer surface, and a ring part radially between the inner bore and the circumferential outer surface,
wherein the adapter element is arranged below the extrusion head, and
wherein the adapter element has an outer ring part connected to the annular housing, a cylindrical inner part connected to the central quill and a frustoconical inner part axially movable relative thereto.

The molding device according to the invention offers advantages. In particular, the strip-shaped preforms produced with the molding device according to the invention have a homogeneous and uniform layer distribution, which has a favorable effect on the material properties of the end product to be produced. The number of channels formed in the molding device and thus the strip-shaped preforms produced is preferably two, although more than two channels distributed over the circumference are also conceivable, e.g. three or four. The channels have the same design as each other, so that the same flow and molding behavior of the different preforms is also guaranteed.

According to a preferred embodiment, the cutting edges arranged between the annular section-shaped inlet openings, viewed in a cylinder section, diverge from the inlet opening to the outlet opening. This means that the cutting edges form or delimit the lateral ends of the slotted channels. The channels are preferably straight on the outlet side, viewed in cross section through the device. This is particularly favorable for further processing.

According to a preferred embodiment, the molding tool comprises an inner part and an outer part, with the channels each being formed between an outer surface of the inner part and an opposite inner surface of one outer part. It is particularly favorable for a uniform flow behavior of the preform if the inner surface of the outer part and the outer surface of the inner part are designed in such a way that the channels formed between them taper in the direction of flow of the preform. The inner surface of the outer part and the outer surface of the inner part are designed in such a way that they are complementary to one another.

The outer surface and inner surface forming the channel are preferably shaped in such a way that the lengths of the streamlines of the preform between the annular inlet opening and the elongated outlet opening are approximately the same length. This means that the channel is ideally designed in such a way that the flow rate of the preform is approximately constant over the cross section of the respective channel. As a result, a particularly favorable flow behavior is achieved when the preform flows through the mold and thus a uniform layer distribution. Different streamline lengths can be accommodated by adjusting the channel thickness accordingly. In concrete terms, the outer surface lying opposite one another and the inner surface of a channel each have a flat partial surface. This is designed approximately in the form of an isosceles triangle, the apex of the triangle being in the center of the edge delimiting the annular segment-shaped inlet opening and the side of the triangle opposite the apex forming the edge of the elongated outlet opening. Two curved sub-areas, which are mirror-symmetrical to one another, adjoin laterally adjacent to the flat triangular area. In this case, transition surfaces with relatively small radii are formed between the side edges of the flat surface and the curved partial surfaces.

According to a preferred embodiment, the outer part is composed of two half-elements that are subsequently connected to one another. The same applies to the inner part. The two-part design also makes it possible, in particular, to produce large molds at a reasonable cost. Preferably, the half-members of the inner member each have two outwardly projecting lugs for aligning and connecting with the half-members of the outer member. In this way, an exact positioning of the half elements relative to one another is made possible, so that the channels are also formed correctly. Of course, the outer part and the inner part can also be produced in one piece and subsequently connected to one another in a corresponding alignment. Conventional means can be used to connect the individual components, for example screw connections.

The molding device according to the invention offers the above-mentioned advantages of a favorable flow pattern of the preform and thus a uniform layer structure. The extrusion head used can be either a continuously or steadily working extrusion head or a discontinuous or strokewise working extrusion head.

An adapter element is arranged between the extrusion head and the mold, which has an inlet opening that matches the annular outlet opening of the extrusion head and an outlet opening that matches the annular section-shaped inlet openings of the mold. The adapter element is used to adapt the diameter of the tubular preform to the width of the strip-shaped preforms to be produced.

According to a preferred embodiment, a wall thickness control device is provided for controlling the thickness of at least one of the band-shaped preforms, which is connected to the mold and has at least one slot channel which connects to one of the elongated outlet openings of the mold and opens into an elongated outlet gap. The wall thickness control device offers the advantage that plastic strips can be produced with partial wall areas of greater thickness and wall areas of lesser thickness. In this way, special circumstances in the end product to be manufactured can already be taken into account during the production of the preform, which has an overall positive effect on the strength and rigidity while at the same time being light in weight. It is envisaged that the wall thickness can be changed over the entire width of the strip-shaped preform, i.e. a wavy profile can be generated over the length, or that the wall thickness can be changed at defined points across the width of the strip-shaped preform, i.e. individual Projections are generated.

In concrete terms, the wall thickness control device comprises at least one adjusting element, which delimits the exit gap laterally and can be adjusted transversely to the direction of flow of the preform. The adjusting element can be designed in the form of a bar, which extends over the entire length of the exit slot, with several adjusting drives being provided along its length for adjusting the bar transversely to the exit slot. Preferably, the beam has end portions which are held in recesses in a frame member defining the outlet are. This ensures that shortening of the length of the beam, which occurs due to bending across the die, is compensated for. An unwanted gap formation between the ends of the beam and the frame when changing the wall thickness is prevented. It is envisaged that the wall thickness can be changed statically or dynamically. In the case of dynamic adjustment, a control unit is to be provided with which the actuators are controlled during the forming process.

According to a preferred embodiment, the wall thickness control device comprises an inner part and an outer part, between which a number of channels corresponding to the number of outlet openings of the mold are formed. The gap width of the outlet gaps of the channels can be changed by axial adjustment of the inner part relative to the outer part. The inner part preferably comprises a stationary connection body and an adjusting body accommodated therein and axially adjustable relative to it, which forms the inner surfaces of the slotted channels in the area of the outlet gaps. The thicknesses of the outlet gaps are changed by axial adjustment of the internal adjusting element.

According to a possible further development, a glass tool for the production of plastic hollow bodies is connected downstream of the shaping device or the wide-slot tool. As an alternative to this, a deep-drawing device can also be provided for deep-drawing at least one of the band-shaped preforms. Alternatively or in addition, a smoothing device is also conceivable, which is used to smooth at least one of the band-shaped preforms after it has exited the shaping device.

• 1 eine erfindungsgemäße Formvorrichtung im Längsschnitt gemäß Schnittlinie I-I aus 3 mit einem erfindungsgemäßen Formwerkzeug;
• 2 eine erfindungsgemäße Formvorrichtung im Längsschnitt gemäß Schnittlinie II-II aus 3 mit einem erfindungsgemäßen Formwerkzeug;
• 3 das Formwerkzeug aus 1 in Draufsicht als Drahtlinienmodell;
• 4 die Formvorrichtung aus 1 in perspektivischer Explosionsdarstellung;
• 5 das Innenteil des Formwerkzeugs aus 1 in perspektivischer Ansicht;
• 6 das Innenteil des Formwerkzeugs aus 1 in perspektivischer Draufsicht;
• 7 das Außenteil des Formwerkzeugs aus 1 in perspektivischer Ansicht;
• 8 das ein Außenteil und ein Innenteil des Formwerkzeugs aus 1 auseinandergeklappt in perspektivischer Darstellung;
• 9 einen Teilschnitt eines das Formwerkzeug nach 1 durchlaufenden Vorformlings in perspektivischer Ansicht;
• 10 das Formwerkzeug aus 1 mit Wanddickenregelvorrichtung in einer ersten Ausführungsform in Draufsicht als Drahtlinienmodell;
• 11 das Formwerkzeug gemäß Schnittlinie XI-XI aus 10 ;
• 12 eine Wanddickenregelvorrichtung in einer zweiten Ausführungsform im Teillängsschnitt;
• 13 die Wanddickenregelvorrichtung aus 12 im Teilquerschnitt durch die Stellelemente;
• 14 eine Wanddickenregelvorrichtung in einer dritten Ausführungsform im Teillängsschnitt;
• 15 eine Wanddickenregelvorrichtung in einer vierten Ausführungsform im Teillängsschnitt;
• 16 das Detail XVI aus 15 ;
• 17 die Formvorrichtung nach 1 (ohne Extrusionskopf) mit nachgeschaltetem Glaswerkzeug in perspektivischer Ansicht;
• 18 die Formvorrichtung nach 1 (ohne Extrusionskopf) mit nachgeschalteten Tiefziehvorrichtungen in perspektivischer Ansicht;
• 19 die Formvorrichtung nach 1 (ohne Extrusionskopf) mit nachgeschalteten Glättvorrichtung in perspektivischer Ansicht;

Preferred exemplary embodiments are explained below with reference to the drawing figures. Show it

• 1 a molding device according to the invention in longitudinal section according to section line II 3 with a mold according to the invention;
• 2 a molding device according to the invention in longitudinal section according to section line II-II 3 with a mold according to the invention;
• 3 the forming tool 1 in plan view as wireline model;
• 4 the forming device 1 in a perspective exploded view;
• 5 the inner part of the mold 1 in perspective view;
• 6 the inner part of the mold 1 in perspective top view;
• 7 the outer part of the mold 1 in perspective view;
• 8th which consists of an outer part and an inner part of the mold 1 unfolded in perspective view;
• 9 a partial section of the molding tool 1 continuous preform in a perspective view;
• 10 the forming tool 1 with wall thickness control device in a first embodiment in plan view as a wire line model;
• 11 the mold according to section line XI-XI 10 ;
• 12 a wall thickness control device in a second embodiment in partial longitudinal section;
• 13 the wall thickness control device 12 in partial cross-section through the actuating elements;
• 14 a wall thickness control device in a third embodiment in partial longitudinal section;
• 15 a wall thickness control device in a fourth embodiment in partial longitudinal section;
• 16 the detail XVI from 15 ;
• 17 the forming device 1 (without extrusion head) with downstream glass tool in a perspective view;
• 18 the forming device 1 (without extrusion head) with downstream deep-drawing devices in a perspective view;
• 19 the forming device 1 (without extrusion head) with downstream smoothing device in a perspective view;

The 1 until 8th are described together below. A molding device 2 for producing band-shaped preforms from plastic can be seen. The molding device 2 comprises an extrusion head 3, of which only the end piece is shown, an adapter element 4, a molding tool 5 and a wall thickness control device 6, which are connected to one another in series. The structural unit consisting of the adapter element 4, the mold 5 and the wall thickness control device 6 can also be referred to as a wide slot tool.

The extrusion head 3 has an annular housing 7 with an inner bore 8, a central sleeve 9 with a circumferential outer surface 10 and an annular part 11 radially between these. It can be seen that between the ring part 11 and the A first ring channel 12 is formed on the sleeve 8 , a second ring channel 13 is formed inside the ring part 11 , and a third ring channel 14 is formed between the ring part 11 and the housing 6 . Extrudate is pressed from all three ring channels 12, 13, 14 in the direction of the ring opening 15. The three streams of extrudate converge in the mouth area of the three ring channels 12, 13, 14 in order to form a multi-layer preform.

The extrusion head 3 shown is therefore a coextrusion system.

Below the extrusion head 3 the adapter 4 is provided, which has an outer annular part 16 connected to the housing 7, a cylindrical inner part 17 connected to the quill 9 and an inner part 18 in the form of a truncated cone which can be moved axially relative to this. The outer ring part 16 is connected to the housing 7 and the inner part 17 to the quill 9 by means of screw connections, which are not shown here. The truncated cone-shaped inner part 18 has a central bore 22 into which the cylindrical inner part 17 is pushed with its cylindrical outer surface 23 . In this way, a length compensation that results from manufacturing tolerances and different thermal expansion of the components can be compensated.

The mold 5 according to the invention, which is composed of an outer part 24 and an inner part 25 , connects below the adapter element 4 . The connection is made, for example, by means of screw connections, which are not shown. In order to center the molding tool 5 relative to the adapter element 4 on the longitudinal axis A, the inner part 25 has a circumferential annular projection 32 on its upper end face, which engages in a corresponding circumferential recess 33 in the frustoconical inner part 18 . It can be seen that two channels 26, 26' are formed between the outer part 24 and the inner part 25, each of which has an inlet opening 27, 27' in the form of a segment of a ring and a straight outlet opening 28, 28'. The channels 26 , 26 ′ are each formed between an inner surface 29 , 29 ′ of the outer part 24 and an opposite outer surface 30 , 30 ′ of the inner part 25 .

In particular with reference to the 5 until 8th further special features of the molding tool 5 are explained below. It can be seen that the outer part 24 and the inner part 25 are each designed in two parts, with the two half-elements 34, 34' of the outer part 24 and the two half-elements 35, 35' of the inner part 25 being identical to one another. The separation of the outer part 24 and the inner part 25 facilitates the manufacture of larger molds; the inner part and the outer part can, of course, also be produced in one piece. The division of the outer part and the inner part is selected in such a way that the inner surface 29, 29' of the outer half element 34, 34' and the outer surface 30, 30' of the inner half element 35, 35' face each other and the side walls of one of the channels 26, 26 ' form. The outer surface and the inner surface of the two channels 26, 26' are designed in such a way that the lengths of imaginary streamlines between the inlet opening 27, 27' in the form of a segment of a ring and the elongated or straight outlet opening 28, 28' are approximately the same length. In this way it is achieved that the flow rate of the preform over the cross section of the channel 26, 26' is approximately constant, whereby a favorable flow behavior and thus a uniform layer distribution of the preform is ensured. For this purpose, the opposite outer surface 29, 29' and the inner surface 30, 30' of a channel 26, 26' each have a flat partial surface 38, 38'; 39, 39' on. This flat partial surface 38, 38'; 39, 39' has the shape of an isosceles triangle, the apex 40, 40' of which lies in the middle of the edge delimiting the annular section-shaped inlet opening 27, 27', the side 42, 42' of the triangle opposite the apex being the edge of the straight outlet opening 28 , 28'.

In the circumferential direction adjacent to the planar partial surface 38, 38'; 39, 39' close transition surfaces 43, 43'; 44, 44' with relatively small radii, which are divided into curved partial surfaces 45, 45'; 46, 46', which only have constant height gradients. The curved inner partial surfaces are each delimited by an upper edge in the form of a segment of a circle, which adjoins the centering ring 32, the lateral transition surface 44, 44' and an end surface 47, 47' which closes off the channel 26, 26' in the circumferential direction. The transition surface 44, 44' and the end surface 47, 47' converge downwards and meet at the end of the straight outlet opening 28, 28'. The two curved partial surfaces of the inner part and the outer part are mirror-symmetrical to one another, so that the second partial surfaces converge at the opposite end of the outlet opening 28, 28'.

The end surfaces 47, 47' are formed by lateral extensions 48, 48' of the inner part 25, which protrude radially outwards and are designed in one piece with the respective half-element 35, 35'. The end surfaces 47, 47' of two circumferentially adjacent channels 26, 26' taper upwards to form a cutting edge 49, 49'. The cutters 49, 49' thus separate the two inlet openings 27, 27' of the channels 26, 26' in the form of annular segments and serve to divide the tubular preform into two shell-shaped preforms. Down are the lateral end surfaces 47, 47' are rotated through 90° in relation to the radial cutting edge 49, 49' and form the lateral boundary of the respective slot channel at the outlet opening 28, 28', i.e. the connection between the outer surface 29, 29' and the inner surface parallel thereto 30, 30' . The lateral projections 48, 48' of the inner part 25 also have cams 50, 50' projecting in the circumferential direction, which engage in correspondingly shaped recesses 52, 52' of the outer part 25 in order to align the two components 24, 25 with one another. For sealing the channels 26, 26' on the inner part 24 and on the outer part 25 there are sealing surfaces 53, 53'; 54, 54' are provided, which are worked with particularly high manufacturing accuracy and ensure that the components 24, 25 rest against one another in a liquid-tight manner.

Below the mold 5, the wall thickness control device 6 is arranged, which is firmly connected to the mold 5, for example by means of screw connections, not shown here. It is particularly in the 1 and 2 It can be seen that the wall thickness control device 6 comprises an outer part 62, which forms a circumferential, rectangular frame 61, as well as a two-part inner part 63, which is constructed similarly to the inner part of the adapter element 4 and a stationary upper connection body 64 and a lower adjusting body that can be moved axially in relation to this 65 which, viewed in cross-section, have rectangular outer contours. Elongated or straight channels 60, 60' are formed between the outer part 62 and the inner part 63;

The connecting element 64 is firmly connected to the overlying inner part 25 of the mold and has a recess 66 with parallel side walls 67 lying opposite one another, in which the adjusting body 65 with flat outer surface sections 68 is accommodated. The flat surface sections 68 are each adjoined by angled surface sections 69 which form the inner side walls of the straight exit gap 70 . The outer side walls of the exit channels are each formed by an opposite surface of the outer part 62 . It can be seen that the connecting body 64 and the adjusting body 65 each have a central opening 72, 73 through which a pull rod 74 passes. At its lower end, the tie rod 74 has a thread onto which a nut 75 is screwed and secured against unintentional loosening by means of a locking ring 76 . By axially lowering the pull rod 74, which is usually held with its upper end adjustable in height on the extrusion head 3, the adjusting body 65 is also lowered, so that the two outlet gaps 70, 70' enlarge. In this way, the thickness of the band-shaped preform is adjusted as required.

9 shows a section of the preform as it behaves between the inlet opening 27 of the mold 5 in the form of a section of a ring and the outlet gap 70 of the wall thickness control device 6 . It can be seen that after dividing the tubular preform, a plurality of cup-shaped preforms 19 are formed, each having a ring-section-shaped cross-section with two ends. The mean radius of the shell-shaped preforms 19 corresponds to the radius of the inlet openings 27 of the mold. The shell-shaped preforms 19 are shaped as they flow through the mold 2 to form strip-shaped preforms 20 which, viewed in cross section, are straight when they leave the mold 2 . After emerging from the mold 2, the strip-shaped preforms 20 flow through the wall thickness control device 6, where the wall thickness of the preforms is reduced as required. The preform 21 emerges from the wall thickness control device 6 into the environment at the exit gap 70 and can now be further processed accordingly.

The 10 and 11 are described together below. It's one half of the mold tool out 1 shown with a wall thickness control device 62 according to an alternative embodiment. With regard to the similarities, reference is made to the above description, with the same components being provided with the same and modified components with reference numbers with indices placed two lower. The special feature of the present wall thickness control device 62 is that in the outer part 622 several adjusting elements 77 in the form of adjusting slides are arranged along the exit gap 70 which are each actuated by means of an individual adjusting drive 78 . The adjusting slides 77 each have an end face facing the channel 60 which, in longitudinal section, is adapted to the contour of the outer part 622 and forms a side face of the outlet gap 70 . By moving the adjusting slides 77 transversely to the exit gap 70, this is widened or narrowed, so that the wall thickness of the exiting preform can be changed over the length, if necessary, partially in the area of the adjusting slides 77. In the present case, exactly two adjusting slides 77 are provided; however, any other number of adjusting slides can also be used, which can be arranged along the exit slit 70 . In the present case, hydraulic cylinders are provided as actuating drives 78, which can be controlled by a central control system. In that respect it is here a dynamically controlled wall thickness control device. Of course, other drive options for controlling the actuating elements are also conceivable, for example electric motor drives.

The 12 and 13 are described together below. It's one half of the mold tool out 1 shown with a wall thickness control device 63 according to a further embodiment. With regard to the similarities, reference is made to the above description, with the same components being provided with the same and modified components with reference numbers with indices placed three lower. The present wall thickness control device 63 is characterized in that the adjusting element 773 is designed in the form of an adjusting bar, which is preferably made of elastic spring steel. It can be seen that the adjusting bar 773 extends over the entire length of the channel 60 in the area of the exit slit 70 . The actuating beam 773 has on its back several connecting means 82 distributed regularly over the length, to each of which a piston rod 83 of the associated actuating drive 78 is connected. In this way, the width of the outlet slit 70 can be changed partially over its length, ie, depending on requirements, a larger wall thickness can be produced in one section and a smaller wall thickness in a section of the preform adjacent thereto.

This enables the contour of the preform to be optimally adapted to the requirements of the semi-finished product or end product that is produced from the preform. The control also takes place dynamically, that is, the actuators 78 can be controlled individually by a central control unit, so that the actuating bar 773 can assume any contours. The actuating bar 773 is accommodated in a recess 84 in the outer part 623 running parallel to the outlet gap 70 so that it can move axially with respect to the piston rod 83, the recess 84 being closed off at the bottom by a cover plate 85 which is firmly connected to the outer part 623, for example by means of screw connections. In its lower region, the adjusting bar 773, which is held in a sealing manner between the wall closing off the recess 84 at the top and the cover plate 85, is slightly angled outwards. In the mutually opposite lateral frame parts 79 of the outer part 62, grooves 80 are provided, in which the adjusting bar 773 engages with its end sections. In this way, a shortening of the "overall length" of the actuating bar 773 caused by the actuation of the actuating drives 78 can be compensated for without an undesired gap occurring between the channel 60 and the lateral recess 84 .

14 shows a further embodiment of a wall thickness control device 6, which is constructed similarly to the embodiments according to the 12 or. 13 . With regard to the similarities, reference is made to the above description, with the same components being provided with the same and modified components with reference numbers with indices placed four lower. In contrast to the above wall thickness control devices, the present one is purely mechanical, ie statically adjustable. A plurality of adjusting elements 774 are provided over the length of the exit slit 70, each of which is designed in the form of an adjusting cam. The adjusting cams 774 are articulated relative to the outer part 624 and can be actuated by means of a rod 83 . At its end on the cam side, the rod 83 carries a joint head 86 which is axially supported on a holding plate 87 which is firmly connected to the adjusting cam 774 . At its opposite outer end, the rod 83 has a head 88 which is received in a threaded sleeve 89 and fixedly connected thereto. The threaded sleeve 89 has an external thread 90 with which it is screwed into a bore in the outer part 62 with a corresponding internal thread 92 .

At its outer end, the threaded sleeve 89 has a polygon 93 through which the torque can be introduced. By rotating the threaded sleeve 89, the rod 83 can thus be shifted axially forwards or backwards, so that the adjusting cam narrows or widens the outlet gap 70 accordingly.

In the 15 and 16 Another embodiment of a wall thickness control device 65 is shown, which is arranged on the inside of the channel. With regard to the similarities to the above embodiments, reference is made to the above description, identical components being provided with the same and modified components with reference symbols with indices placed five lower. In the present embodiment, the adjustment is also static. The adjusting element 775 is designed in the form of an elastic adjusting lip, which is firmly connected to the axially movable adjusting body 65 by means of a screw connection 94 . The adjusting lip 775 can either extend over the entire length of the outlet slit 70 or several adjusting lips 775 can be distributed over the length. It can be seen that the adjusting body 65 has an angled section 95 on its edge facing the outlet gap 70, to which the adjusting lip 775 is held approximately parallel and at a distance. At the free end of the adjusting lip 775 there is a sleeve 96 into which a screw 97 is screwed, which in turn is axially supported against the angled section 95 in both directions. An annular retaining element 98 is provided for this purpose, which is firmly connected to the angled section 95 is and against which the screw head 91 is supported. The screw 97 is designed as a hexagon socket screw so that a torque can be introduced. Because the screw head 91 is supported in both axial directions relative to the adjusting body 65, the free end of the adjusting lip 775 can be adjusted both inwards and outwards, so that the outlet gap 70 can be both narrowed and widened.

17 shows the molding device 2 according to the invention with a downstream glass tool 57, which is constructed in three parts and comprises two side frames 58, 58' and an intermediate frame 59 arranged between them. It can be seen that the two preforms exiting the molding device 2 in parallel are guided along on both sides of the intermediate frame 59 and between the side frames 58, 58'. After the side frames 58, 58' have been moved towards the intermediate frame 59, air is blown into the intermediate frame 59 so that functional components previously installed in the intermediate frame 59 are connected to the preforms. The side frames 58, 58' are then moved apart again, the intermediate frame is removed and the side frames 58, 58' are closed. In this way, the half-shells molded into the side frames 58, 58' come into contact with one another along the peripheral edge and are connected to form a hollow body.

18 shows the molding device 2 according to the invention with a downstream deep-drawing device 99, 99' for each emerging band-shaped preform. The plastic strips are first deflected on deflection rollers 100, 100' before they are fed to the respective deep-drawing device 99, 99'.

19 shows the molding device according to the invention with a downstream smoothing device or calender unit 55, 55' for each emerging band-shaped preform. The plastic strips are rolled out by the smoothing rollers 56, 56' arranged parallel to one another, the thickness of the plastic strips being changed as required for further processing.

Overall, the molding device according to the invention results in a uniform layer structure of the preform produced, regardless of the post-processing provided, which also has an effect on the end product to be produced therefrom.

2

molding device

3

extrusion head

4

adapter element

5

molding tool

6

wall thickness control device

7

Housing

8th

inner bore

9

quill

10

outer surface

11

ring part

12

ring canal

13

ring canal

14

ring canal

15

ring opening

16

ring part

17

inner part

18

inner part

19

cup-shaped preform

20

ribbon preform

21

emerging preform

22

drilling

23

outer surface

24

outer part

25

inner part

26

channel

27

entry opening

28

entry opening

29

Inner surface

30

outer surface

32

head Start

33

recess

34

half element

35

half element

38

face

39

face

40

apex

42

Page

43

transition surface

44

transition surface

45

face

46

face

47

end face

48

head Start

49

cutting edge

50

cam

52

recess

53

sealing surface

54

sealing surface

55

smoothing device

56

smooth roller

57

glass tool

58

side frame

59

intermediate frame

60

channel

61

Frame

62

outer part

63

inner part

64

connection element

65

actuator

66

recess

67

Side wall

68

area section

69

area section

70

exit slit

72

breakthrough

73

breakthrough

74

pull bar

75

Mother

76

locking ring

77

actuator

78

actuator

79

frame part

80

groove

82

connection means

83

piston rod

84

recess

85

cover plate

86

rod end

87

Retaining plate

88

Head

89

threaded sleeve

90

external thread

91

screw head

92

inner thread

93

polygon

94

screw connection

95

Section

96

sleeve

97

screw

98

holding part

99

thermoforming device

100

Deflection roller A longitudinal axis

Claims (11)

Molding device for the production of band-shaped plastic preforms, comprising an extrusion head (3) and a molding tool connected at least indirectly to the extrusion head (3) and having a plurality of channels (26), each of which has an inlet opening (27) in the form of a segment of a ring and an elongate outlet opening (28), wherein the inlet openings (27) in the form of annular sections are distributed over the circumference on a common radius and are separated from one another by radially running cutting edges (49) and wherein between the extrusion head (3) and the mold (5) an adapter element (4) is arranged, which has an inlet opening that matches the annular outlet opening of the extrusion head (3) and an outlet opening (27) that matches the annular section-shaped inlet openings (27) of the mold (5). 28) has, wherein the extrusion head (3) has an annular housing (7) with an inner bore (8), a central sleeve (9) with a peripheral outer surface (10), and radially between the inner bore (8) and the peripheral outer surface (10) an annular part (11 ) having, wherein the adapter element (4) is arranged below the extrusion head (3), and the adapter element (4) having an outer annular part (16) connected to the annular housing (7), a cylindrical inner part (17) connected to the central sleeve (9) and an inner part (18) in the shape of a truncated cone which can be moved axially relative thereto. molding device claim 1 , characterized in that a wall thickness control device (6) is provided for controlling the thickness of at least one of the strip-shaped preforms, which is connected to the mold (5) and has at least one channel adjoining one of the elongated outlet openings (28) of the mold (5). , which opens into an elongated exit slit (70). molding device claim 2 , characterized in that the channel is designed in such a way that the lengths of imaginary flow lines between the annular section-shaped inlet opening (27) and the elongated outlet opening (28) are approximately the same length. Forming device according to one of claims 2 until 3 , characterized in that the wall thickness control device (6) has at least one adjusting element (77) which delimits the outlet gap (70) laterally and can be adjusted transversely to the direction of flow of the preform. molding device claim 4 , characterized in that the adjusting element (77) is designed in the form of an adjusting bar which extends over the entire length of the exit slit (70), with several adjusting drives (78) being provided along its length for adjusting the bar transversely to the exit slit (70). are. molding device claim 5 , characterized in that the adjusting bar has end sections which are held in grooves (80) of a frame part (79) delimiting the outlet gap (70). Forming device according to one of claims 2 until 6 , characterized in that the wall thickness control device (6) comprises an inner part (63) and an outer part (62), wherein between the inner part (63) and the outer part (62) one of the number of elongated outlet openings (28) of the mold (5) corresponding number of channels (60) are formed, the gap width of the outlet gaps (70) of the channels being variable by axial displacement of the inner part (63) relative to the outer part (62). molding device claim 7 , characterized in that the inner part (63) has a stationary connection body (64) and an adjusting body (65) accommodated therein and axially adjustable relative to it, which forms the inner surfaces of the channels (60) in the region of the outlet gap (70). Forming device according to one of Claims 1 until 8th , characterized in that the shaping device (2) is followed by a glass tool (57) for producing hollow bodies from the strip-shaped preforms. Forming device according to one of Claims 1 until 8th , characterized in that the shaping device (2) is followed by a deep-drawing device (99) for deep-drawing at least one of the band-shaped preforms. Forming device according to one of Claims 1 until 8th , characterized in that the shaping device (2) is followed by a smoothing device (55) for smoothing at least one of the band-shaped preforms.

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