DE102020203300B3 - Process for producing a plastic canister and blow mold for carrying out the process - Google Patents

Abstract

The invention relates to a method for producing a canister (50) made of plastic, comprising the following steps: Continuously extruding a hose (102), positioning an open blow mold (1) around the hose (102) so that the hose (102) is between the two blow mold halves (2), closing a tube gripper (3) arranged on the blow mold (1) for clamping the tube (102) and at the same time keeping the tube (102) open on its upper side to form an entry opening (104), separating the tube (102) above the tube gripper (3) to form the preform (106), horizontal movement of the blow mold (1) together with the preform (106) suspended therein and held by the tube gripper (3) into a blowing position (105), insertion of a blow pin arrangement (30) ) from above into the entry opening (104) of the preform (106), closing the blow mold halves (2), inflating the preform (106) in the blow mold (1) to form a canister (50).

Description

The invention relates to a method for producing a plastic canister. The invention also relates to a blow mold for producing a plastic canister.

The registration shows a previously known canister, for example EP 0 677 445 A1 .

The canister disclosed there is a plastic canister with a ventilation channel formed on the top and extending vertically within the pouring opening to enable gurgling-free emptying. The canister disclosed there is produced in the extrusion blow molding process using an accumulator blow head. The extruded tube, which is open at the bottom, moves between the open blow mold halves over the blow pin positioned below. Before the blow mold halves are closed, the blow pin can then be moved horizontally within the plasticized plastic tube into the desired, mostly asymmetrical position in which the pouring opening of the canister is to be formed. The blow mold then closes and the plasticized plastic tube is inflated inside the blow mold. The disadvantage of this method, however, is that the extrusion of the hose cannot continue continuously during the inflation process, since the blow mold including the blow pin is located directly under the outlet of the accumulator blow head during the entire production period of the canister and thus hinders the further ejection of a new hose . The duration of the hose ejection is always added to the inflation time of the canister, which extends the total production time of the canister.

The aforementioned canister with a ventilation channel extending vertically within the pouring opening and a canister with an internal thread in the pouring opening cannot be produced in the faster blowing process of continuous extrusion. In this process, the extruded tube is continuously ejected. Once the required hose length has been reached, the open blow mold halves waiting in the neighboring position move in front of and behind the hose, close and clamp it in order to move the clamped hose back to the neighboring position after it has been cut on the extruder. A corresponding blow pin then moves vertically from above into the opening made in the blow mold, dividing the jammed tube, thus forming the canister pouring opening and blowing open the tube.

When dividing the hose, the vertically penetrating blow pin pushes excess plasticized material down into the inside of the produced canister, which in the case of a canister pouring opening with a ventilation channel formed inside it causes the same to close or, in the case of an opening with an internal thread, damages the threads.

U.S. 3,032,809 A shows a method according to the preamble of claim 1.

U.S. 3,681,486 A shows a method for producing bottles or the like by blow molding. What is shown is a blow mold with two flaps that initially clamp the hose. When the blow pin is inserted, the flaps are folded down so that the blow pin can penetrate the hose between the two flaps.

It is the object of the present invention to provide a method for producing a blow-molded plastic canister with a ventilation channel extending vertically within the pouring opening or a pouring opening with an internal thread, which makes it possible to manufacture such a canister quickly and easily.

The problem is solved by the features of the independent claims. The dependent claims relate to advantageous embodiments of the invention.

1. a) Es erfolgt ein kontinuierliches Extrudieren eines Schlauches aus einem Kunststoff. Hierzu wird in üblicherweise Kunststoffgranulat plastifiziert und durch einen Blaskopf gepresst. Dabei entsteht ein kontinuierlich vorgeschobener, nach unten hängender Schlauch. Das kontinuierliche Extrudieren erfolgt insbesondere ohne Unterbrechung, so dass während des Abnehmens des zur Produktion erforderlichen Schlauchstückes als auch während des Aufblasens desselben, der Schlauch weiterhin extrudiert wird.
2. b) Während des Extrudierens des Schlauches erfolgt ein Positionieren einer geöffneten Blasform um den Schlauch. Diese Blasform umfasst zwei Blasformhälften. In diesen Blasformhälften ist das Formnest für einen Kanister ausgebildet. Die geöffnete Blasform wird unterhalb des Blaskopfes so um den Schlauch herum positioniert, dass sich der Schlauch zwischen den beiden auseinandergefahrenen und somit geöffneten Blasformhälften befindet.
3. c) Im nächsten Schritt erfolgt nicht wie üblich ein Schließen der Blasform bzw. der Blasformhälften. Vielmehr ist an der Blasform ein Schlauchgreifer vorgesehen. Dieser Schlauchgreifer ist zum Einklemmen des Schlauches und gleichzeitigem Offenhalten des Schlauches an seiner Oberseite ausgebildet. Der Schlauchgreifer befindet sich hierzu auf der Oberseite der Blasform und ist zusammen mit der Blasform bewegbar. Zum Einklemmen des Schlauches sind wiederum Bestandteile des Schlauchgreifers relativ zu den beiden Blasformhälften beweglich, so dass ohne Schließen der Blasformhälften der Schlauch mit dem Schlauchgreifer eingeklemmt werden kann. Der Schlauchgreifer klemmt dabei den Schlauch nicht über seinen gesamten Querschnitt, sondern lediglich an der Seite, so dass der Schlauch an seiner Oberseite offen bleibt. Diese Öffnung wird als „Einfahröffnung“ bezeichnet, da über diese Öffnung später die Blasanordnung einfährt.
4. d) Im nächsten Schritt erfolgt ein Trennen des Schlauches oberhalb des Schlauchgreifers, so dass der Vorformling vom kontinuierlich extrudierenden Schlauch abgetrennt wird. Nach dem Trennen hängt der Vorformling in der geöffneten Blasform; gehalten durch den geschlossenen Schlauchgreifer. Das Trennen bzw. die Trennvorrichtung ist so ausgestaltet, dass der Schlauch gleichzeitig getrennt und darüber geschlossen wird, so dass der nächste Vorformling an seiner Unterseite geschlossen ist.
5. e) Da der Schlauch kontinuierlich weiter extrudiert wird und sich dadurch nach unten ausbreitet, wird die Blasform samt darin hängendem Vorformling horizontal in eine sog. „Blasposition“ verfahren. In dieser Blasposition befindet sich die Blasform außerhalb des Bereiches unter dem Blaskopf.
6. f) Die Blasform ist in der Blasposition zunächst immer noch geöffnet. Es erfolgt nun das Einfahren des Blasdornes von oben in die Einfahröffnung des Vorformlings. Hier zeigt sich ein wesentlicher Vorteil der Erfindung: Gäbe es keinen Schlauchgreifer, der den Vorformling mit der Einfahröffnung offen hält, wäre zu diesem Zeitpunkt die Blasform geschlossen, um so den Vorformling zu fixieren und in die Blasposition zu verschieben. Würde nun die Blasanordnung von oben in die für den Stutzen des Kanisters formgebende Öffnung einfahren, so käme es, aufgrund dieser relativ engen Öffnung, zu einem Verschieben bzw. Schoppen des Materials (Kunststoff) nach unten. Dadurch könnte sich im unteren Bereich des Stutzens eine Materialanhäufung ergeben. Dies ist insbesondere nachteilig bei Ausformung eines Belüftungskanals im Stutzen mittels eines relativ kleinen Nebendorns. Dieser relativ kleine Nebendorn zur Ausbildung des Belüftungskanals mit relativ kleinem Durchmesser könnte bei Schoppen des Materials zu einer signifikanten Einengung oder Verschließung des Belüftungskanals führen. Ebenso wäre dies nachteilig bei der Produktion einer Mündung mit Innengewinde, da die Gewindegänge so verletzt werden können. Um eben diese Nachteile zu vermeiden, wird die Blasform zunächst nicht geschlossen, sondern der Vorformling nur mittels des Schlauchgreifers gehalten. Dabei verbleibt die Einfahröffnung auf der Oberseite des Schlauches, die wesentlich größer ist als die für den Stutzen formgebende Öffnung der Blasform. Insbesondere ist vorgesehen, dass die offen gehaltene Einfahröffnung zumindest die doppelte Fläche der für den Stutzen formgebenden Öffnung des Blaswerkzeugs aufweist. So kann der Blasdorn ohne Kontakt mit dem Vorformling einfahren.
7. g) Im darauffolgenden Schritt, wenn der Blasdorn bereits in die Einfahröffnung des Vorformlings eingefahren ist, erfolgt erst das vollständige Schließen der Blasformhälften bzw. der Blasform.
8. h) Nach dem vollständigen Schließen der Blasformhälften erfolgt das Aufblasen des Vorformlings in der Blasform zu einem Kanister. Hierzu wird über den Blasdorn Druckluft ins Innere des Vorformlings eingeblasen, so dass sich der Schlauch an die Innenseite des Formnestes in der Blasform anlegt.

The method according to the invention comprises at least the following steps in the given order:

1. a) There is a continuous extrusion of a hose made of a plastic. For this purpose, plastic is usually plasticized in granulate and pressed through a blow head. This creates a hose that is continuously pushed forward and hanging down. The continuous extrusion takes place in particular without interruption, so that the hose continues to be extruded while the hose piece required for production is removed and while it is being inflated.
2. b) During the extrusion of the tube, an open blow mold is positioned around the tube. This blow mold comprises two blow mold halves. The mold cavity for a canister is formed in these blow mold halves. The opened blow mold is positioned underneath the blow head around the tube in such a way that the tube is located between the two blow mold halves that have moved apart and are thus opened.
3. c) In the next step, the blow mold or the blow mold halves are not closed as usual. Rather, a hose gripper is provided on the blow mold. This hose gripper is designed to clamp the hose and at the same time keep the hose open on its upper side. For this purpose, the hose gripper is located on the top of the blow mold and can be moved together with the blow mold. To clamp the hose, in turn, components of the hose gripper are movable relative to the two blow mold halves, so that the hose can be clamped with the hose gripper without closing the blow mold halves. The hose gripper does not clamp the hose over its entire cross section, but only on the side, so that the hose remains open on its upper side. This opening is referred to as the "entry opening" because the blower assembly will later enter through this opening.
4. d) In the next step, the tube is separated above the tube gripper, so that the preform is separated from the continuously extruding tube. After separation, the preform hangs in the open blow mold; held by the closed hose gripper. The separating or separating device is designed in such a way that the tube is separated and closed over it at the same time, so that the next preform is closed on its underside.
5. e) Since the tube is continuously extruded and thus spreads downwards, the blow mold including the preform hanging in it is moved horizontally into a so-called "blow position". In this blow position, the blow mold is outside the area under the blow head.
6. f) The blow mold is initially still open in the blow position. The blow mandrel is now inserted from above into the entry opening of the preform. This shows an essential advantage of the invention: If there were no tube gripper that holds the preform with the entry opening open, the blow mold would be closed at this point in time in order to fix the preform and move it into the blow position. If the blower assembly were to move from above into the opening forming the shape of the nozzle of the canister, this relatively narrow opening would cause the material (plastic) to be displaced or popped downwards. This could result in an accumulation of material in the lower area of the nozzle. This is particularly disadvantageous when a ventilation channel is formed in the connecting piece by means of a relatively small auxiliary mandrel. This relatively small auxiliary mandrel for forming the ventilation channel with a relatively small diameter could lead to a significant narrowing or closure of the ventilation channel when the material is popped. This would also be disadvantageous in the production of an orifice with an internal thread, since the threads can be damaged in this way. In order to avoid precisely these disadvantages, the blow mold is initially not closed, but rather the preform is only held by means of the tube gripper. The entry opening remains on the upper side of the hose, which is significantly larger than the opening of the blow mold which gives the nozzle the shape. In particular, it is provided that the entry opening, which is kept open, has at least twice the area of the opening of the blow molding tool which forms the nozzle. This allows the blow pin to move in without contact with the preform.
7. g) In the next step, when the blow mandrel has already moved into the entry opening of the preform, the blow mold halves or the blow mold are only completely closed.
8. h) After the blow mold halves have been completely closed, the preform is inflated in the blow mold to form a canister. For this purpose, compressed air is blown into the interior of the preform via the blow mandrel, so that the hose rests against the inside of the mold cavity in the blow mold.

In the following steps, the blow mold can be opened and the canister removed in the usual way.

During all of these process steps, the tube continues to be extruded at the extrusion head, so that after the canister has been removed, the opened blow mold is moved horizontally under the tube head again in order to grasp the next preform with the tube gripper. The result is a continuous process in which continuous extrusion takes place and canisters can thus be manufactured as quickly and reliably as possible.

The “open” blow mold or “open” blow mold half described here refer to a state of the blow mold in which the blow mold halves are at least not completely closed. In particular, the two blow mold halves are at least moved so far apart that the preform can hang between them with a sufficiently large insertion opening.

The canister produced with the method according to the invention has in particular the following features. The canister preferably comprises a nozzle for pouring in and pouring out. A ventilation channel preferably protrudes into this connecting piece. The ventilation channel in turn preferably comprises a horizontal section and a vertical section. The vertical section of the ventilation duct preferably extends into the connecting piece and preferably ends below the upper end of the connecting piece.

This results in two openings in the connecting piece, namely a main opening through which liquid can be poured into an interior of the canister and poured out again, and a ventilation opening which is formed by the vertical section of the ventilation channel. The ventilation channel leads over the horizontal section to a rear area of the interior. The purpose of the ventilation duct is in EP 0 677 445 A1 described in detail.

The blow pin arrangement used in the context of the method preferably comprises a main blow pin and a secondary blow pin. A pinch edge gap is preferably provided between the main blowing mandrel and the secondary blowing mandrel. The two blow mold halves have a pinch edge. When the blow mold is closed, the two opposite pinch edges of the two blow mold halves protrude into this pinch edge gap between the main blow pin and the secondary blow pin, so that an inner channel wall of the ventilation channel is created in the area of the nozzle. However, this squeezing to form the inner channel wall only takes place after the blow pin arrangement is already in place in the preform, so that during the closing of the two blow mold halves, both the main blow pin and the secondary blow pin give shape to the main opening and the ventilation opening in the nozzle of the canister are.

The hose gripper includes gripping elements. In the hose gripper, the parts that can be moved relative to the blow mold halves in order to clamp the hose between the gripping elements are referred to as gripping elements. Accordingly, there is also at least one gripping element on each blow mold half. The respective gripping element is movably guided on its blow mold half, so that the gripping elements can be moved towards one another in the mold closing direction of the blow mold.

Gripping areas are defined on the gripping elements that actually make contact with the hose. A gripping area consists of two opposing, mutually complementary surfaces of two gripping elements. It is preferably provided that the hose gripper comprises at least two gripping areas that are spaced apart from one another. The hose is clamped at each gripping area. Because the two gripping areas are spaced apart from one another, the described insertion opening remains between the two gripping areas. It is provided that the gripping elements are spring-loaded in the mold closing direction by means of springs. At least one spring is provided per gripping element, which in the tensioned state presses the gripping element in the direction of the hose so that the hose can be clamped. To hold the gripping elements in the open, that is to say retracted position and thus to hold the gripping elements against the spring force, at least one holding device is provided on each blow mold half. This holding device can hold the corresponding gripping element or can block the relaxation of the spring in some other way so that the hose gripper does not close. The holding devices are preferably designed hydraulically or pneumatically, for example as hydraulic cylinders or pneumatic cylinders. The springs can be spiral springs or other energy stores, for example hydraulic or pneumatic energy stores.

In the course of the process it is provided that the springs are tensioned when the blow mold halves are closed. This is possible in a simple manner, since the gripping elements are closed anyway before the blow mold halves are closed and thereby clamp the preform. If the blow mold halves are now also moved towards one another, the springs automatically open up again. When the blow mold halves are subsequently opened, the springs in the tensioned state are held in the tensioned state by the holding devices listed above.

In a variant it is provided that the individual gripping elements are each in two parts. In addition, it is provided in particular that the two parts of the respective gripping element can be moved in the horizontal direction perpendicular to the mold closing direction. This makes it possible for the two gripping areas to be moved towards one another after being clamped in order to change the shape of the entry opening. When the hose or preform is clamped with the hose gripper, an essentially oval entry opening is formed between the two gripping areas. By moving the two gripping areas towards one another, this oval shape can be changed to a more rounded shape. In certain applications, this can result in a shape of the entry opening which enables the blower arrangement to be inserted optimally.

Furthermore, it is preferably provided that compressed air for pre-blowing is blown into the preform before the blow mold halves are closed, that is to say for example during the horizontal movement of the blow mold to the blow position or in the blow position. This pre-blowing can also be referred to as "pre-stretching". Particularly preferably, at least one compressed air nozzle is located on the hose gripper, in particular on one of the gripping elements, via the air for pre-blowing the preform can be blown in before the blow mold halves are closed.

Furthermore, it is preferably provided that the preform is inflated beyond the internal dimensions of the blow mold during the pre-blowing. Until the blow mold is closed, the preform orients itself back a little so that it fits into the mold cavity.

Furthermore, in the method according to the invention, the blow pin arrangement can be moved in the horizontal direction after it has been moved into the entry opening and before the blow mold halves are closed. This enables, for example, a very far outside connection of the canister.

Furthermore, it is preferably provided that the auxiliary mandrel of the blow mandrel arrangement has at least one obliquely arranged compressed air outlet on its underside. Through this compressed air outlet, when the canister is inflated, the compressed air can not only be blown vertically downwards, but also laterally onto the material (plastic). This makes it possible to blow away material to support the shaping that was forced into the ventilation channel when the two blow mold halves were closed.

The invention further comprises a blow mold for producing a canister. In particular, this is the canister already described above. The blow mold is used in particular to carry out the method. It goes without saying that not only the blow mold, but also other elements, in particular the blow head for extruding the tube, can be used to carry out the method.

The blow mold according to the invention comprises two blow mold halves which, with their mold cavity, give the canister its shape. The two blow mold halves can have slides in order to take into account the geometry of the desired canister.

The already described hose gripper with its two gripping elements is located on the blow mold halves. There is at least one gripping element on each blow mold half.

The gripping elements can be moved parallel to the mold closing direction and relative to the respective blow mold half, so that the tube arranged between the opened blow mold halves can be clamped by the gripping elements without the blow mold halves having to be completely closed.

The advantageous configurations and subclaims described in the context of the method according to the invention find correspondingly advantageous applications on the blow mold according to the invention.

In particular, it is provided that the hose gripper has two gripping areas. The respective gripping area is formed by two opposing surfaces of two gripping elements that can be moved towards one another. As described, these two gripping areas are spaced from one another, so that there is an entry opening in the hose when it is clamped by the hose gripper. The hose gripper preferably comprises at least one spring per gripping element. As already described, this spring is designed as any energy storage device, for example as a spiral spring or in some other way.

The springs act on the gripping elements towards one another, so that the gripping elements close by means of the spring force in order to clamp the hose.

Furthermore, the hose gripper comprises holding devices which are designed to hold the gripping elements in the open, spring-loaded position. These holding devices are, for example, hydraulic or pneumatic cylinders.

The holding devices are particularly preferably double-acting cylinders, so that by applying pressure to the cylinders accordingly, it is possible to hold open against the spring force on the one hand and to close the gripping elements supporting the spring force on the other hand.

In a variant, it is preferably provided that the gripping areas can be moved towards one another in order to change the shape of the entry opening. As described, this makes it possible to change the oval entry opening to a more rounded opening.

• 1 eine schematische Ansicht zur Erläuterung des erfindungsgemäßen Verfahrens gemäß einem Ausführungsbeispiel,
• 2 eine Draufsicht auf eine erfindungsgemäße Blasform zur Durchführung des erfindungsgemäßen Verfahrens gemäß dem Ausführungsbeispiel,
• 3 eine Draufsicht auf die geschlossene Blasform aus 2,
• 4 eine Draufsicht auf eine Variante der Blasform aus 2,
• 5 eine Draufsicht auf einen Kanister, hergestellt nach dem erfindungsgemäßen Verfahren gemäß dem Ausführungsbeispiel,
• 6 den in 5 gekennzeichneten Schnitt A-A,
• 7 eine Detailansicht der erfindungsgemäßen Blasform zur Durchführung des erfindungsgemäßen Verfahrens gemäß dem Ausführungsbeispiel,
• 8 eine Detailansicht einer Blasdornanordnung zur Durchführung des erfindungsgemäßen Verfahrens gemäß dem Ausführungsbeispiel, und
• 9 den in 8 dargestellten Schnitt B-B.

Further details, advantages and features of the present invention emerge from the following description of an exemplary embodiment with reference to the drawings. It shows:

• 1 a schematic view to explain the method according to the invention according to an embodiment,
• 2 a plan view of a blow mold according to the invention for performing the method according to the invention according to the embodiment,
• 3 a top view of the closed blow mold 2 ,
• 4th a plan view of a variant of the blow mold 2 ,
• 5 a top view of a canister produced by the method according to the invention according to the embodiment,
• 6th the in 5 marked section AA,
• 7th a detailed view of the blow mold according to the invention for carrying out the method according to the invention according to the embodiment,
• 8th a detailed view of a blow pin arrangement for carrying out the method according to the invention according to the embodiment, and
• 9 the in 8th shown section BB.

In the following we will use the 1 to 9 the inventive method for manufacturing a canister 50 using a blow mold according to the invention 1 explained in detail. Unless otherwise stated in detail, reference is always made to all figures.

1 shows an arrangement 100 that can be used when carrying out the procedure. The representation is purely schematic.

The order 100 includes a blow head 101 with which a hose is continuous 102 is extruded from plastic. The hose 102 depends on the blow head 101 along the vertical 110 downward.

The schematic representation in 1 that arrangement 100 a blow mold 1 includes. This blow mold 1 again has two opposite blow mold halves 2 on. On these blow mold halves 2 there is a hose gripper 3 . Above the hose gripper 3 there is a separator 103 for cutting off and closing the hose at the same time 102 .

In the course of the process, the hose is continuously extruded 102 . The blow mold becomes regular 1 with opened blow mold halves 2 on the hose 102 positioned. Thereupon the blow mold halves 2 not closed, but the hose 102 is only used with the hose gripper 3 clamped. Above the claw gripper 3 will then use the separator 103 the hose 102 separated so that the preform 106 that remains between the two blow mold halves 2 hangs. Without the blow mold halves 2 to close, the blow mold becomes 1 including the preform hanging in it 106 along the horizontal 111 in a blowing position 105 postponed. This is where the blow mold is located 1 no longer under the continuously extruding tube 102 .

At the blowing position 105 will the in 1 Blow pin arrangement shown purely schematically 30th by moving along the vertical 110 into the preform 106 retracted. The blow mold halves then close 2 and inflating the preform 106 to the canister 50 , as it is for example in 5 and 6th is shown.

The following is based on the 2 to 4th the schematic structure of the blow mold 1 explained in detail. 2 shows a plan view of the opened blow mold 1 . 3 shows a top view of the closed blow mold 1 . 4th shows a plan view of an alternative design of the blow mold 1 , shown in the open state.

As already described, the blow mold includes 1 two blow mold halves 2 and a hose gripper 3 . The hose gripper 3 again comprises two gripping elements 4th . On each blow mold half 2 is a gripping element 4th arranged on the top. Every gripping element 4th is along the horizontal 111 parallel to the mold closing direction 11 relative to the blow mold half 2 movable. In the 2 to 4th is the hose gripper 3 each closed. The two opposite gripping elements 4th have approached each other. At two spaced gripping areas 5 is the hose 102 or the preform 106 trapped. By having the two gripping areas 5 are spaced apart, remains between the two gripping areas 5 an entry opening 104 in the hose 102 or preform 106 . Through this entry opening 104 can at the blowing position 105 the blow pin assembly 30th be retracted even before the blow mold halves 2 along the mold closing direction 11 getting closed.

The 2 to 4th show purely schematically that the gripping elements 4th in the direction of their closed position by means of springs 6th are acted upon. These feathers 6th press the gripping elements 4th towards each other. By means of holding devices 7th , for example designed as a pneumatic or hydraulic cylinder, the gripping elements 4th are held in their open position against the spring force.

3 shows the blow mold in plan view 1 in closed position. Here are the blow mold halves 2 completely closed. This has the insertion opening 104 locked. The blow pin assembly 30th protrudes into the preform from above 106 into it.

4th shows a variant in which the gripping elements 4th on the respective blow mold halves 2 are designed in two parts. The gripping elements 4th can be moved towards one another in such a way that the gripping areas 5 can be moved towards each other. This allows the oval shape of the entry opening 104 can be changed to a more rounded shape.

5 Figure 10 shows a top view of the canister 50 who with the arrangement 100 or the blow mold 1 will be produced. 6th shows the in 5 marked section AA.

Accordingly, the canister comprises 50 a topsoil 51 and an opposite sub-floor, not shown. Topsoil 51 and sub-floor are over a lateral surface 64 of the canister 50 connected. So form topsoil 51 , Sub-floor and outer surface 64 an interior 52 of the canister 50 to absorb a liquid.

On the top floor 51 is a handle 53 educated. Before the handle 53 there is a nozzle 54 , designed for pouring the liquid into and out of the interior 52 or from the interior 52 .

The stub 54 closes with a top closure 56 from. At this upper end 56 seals a cover, not shown, which has an external thread 55 of the nozzle 54 can be screwed on.

It is also located on the inside of the topsoil 51 a ventilation duct 57 . The ventilation duct 57 is divided into a horizontal section 58 and into a vertical section 59 .

The ventilation duct 57 is through an outer duct wall 60 and an inner duct wall 61 educated. The inner canal wall 61 is in particular by squeezing off the preform 106 educated. For this purpose, pinch edges are used 8th (see 7th ) on the blow mold halves 2 used. The outer canal wall 60 is in particular an outer wall of the canister 50 .

The ventilation duct 57 protrudes with its vertical section 59 in the nozzle 54 . From the neck 54 the vertical section extends out 59 down and go to the horizontal section 58 over. The horizontal section 58 extends to the rear of the canister 50 and flows into the interior 52 . The horizontal section 58 does not have to be exactly horizontal, but can also be inclined.

Thereby that the ventilation duct 57 in the nozzle 54 extends, divides the inner duct wall 61 the interior of the nozzle 54 into a main opening 62 through which the liquid runs during pouring and pouring, and into a ventilation opening 63 . It is provided in particular that the ventilation opening 63 is much smaller in cross-section than the main opening 62 . In particular, the cross-sectional area of the ventilation opening is 63 at most 25%, preferably at most 20%, of the cross-sectional area of the main opening 62 .

7th shows an area of one of the two blow mold halves 2 . It can be seen that in the blow mold half 2 the corresponding part of the mold cavity 10 is trained. Around the mold cavity 10 run cutting edges 9 that together with the cutting edges of the other blow mold half 2 the preform 106 close and separate.

Also shows 7th that the blow mold halves 2 one pinch edge each 8th have the preform 106 to form the inner duct wall 61 to squeeze. These pinch edges 8th extend corresponding to the vertical section 59 of the ventilation duct 57 also in the area of the nozzle 54 .

8th shows how the blow pin assembly 30th in the canister 50 plugged. For clarity shows 9 the in 8th marked section BB.

The blow pin assembly 30th includes a main mandrel 31 and a secondary mandrel 32 . The main blowing mandrel 31 is located when the blow mold halves are closed 2 and when inflating the canister 50 in the area of the nozzle 54 and is shaping the inside of the main opening 62 . At the same time are the secondary mandrel 32 also when closing the blow mold halves 2 and when inflating the canister 50 in the area of the nozzle 54 and is shaping the inner surface of the ventilation opening 63 or the vertical section 59 of the ventilation duct 57 .

As in particular the cut BB in 9 shows are the main blowing mandrel 31 and the secondary mandrel 32 around a pinch edge gap 36 spaced from each other. As the blow pin assembly 30th when closing the blow mold halves 2 is already in place, pinch the two pinch edges 8th the material into the pinch edge gap 36 . The pinch edges protrude 8th of the blow mold halves 2 also in this pinch edge gap 36 . Through the corresponding position of the secondary blowing mandrel 32 no material gets into the ventilation channel to be created 57 , especially the vertical section 59 , repressed.

The two blow pins 31 , 32 each have a central blow channel 33 for blowing compressed air into the interior 52 on. Around the blow duct 33 is a return channel 34 arranged.

Shows purely schematically 8th that the secondary mandrel 32 an inclined compressed air outlet on its underside 35 or several of these inclined compressed air outlets 35 may have. Via this compressed air outlet 35 becomes air at an angle to the vertical 110 blown out. As a result, anything can get into the ventilation duct that is created 57 forced material are blown away, so that the desired cross-section of the ventilation channel 57 arises.

Furthermore, it is preferably provided that at least one of the gripping elements 4th has a compressed air nozzle which pre-blows the preform 106 before closing the blow mold halves 2 enables.

List of reference symbols

1

Blow mold

2

Blow mold halves

3

Hose gripper

4th

Gripping elements

5

Gripping areas

6th

feathers

7th

Holding device

8th

Pinch edge

9

Cutting edge

10

Mold cavity

11

Mold closing direction

30th

Blow pin assembly

31

Main mandrel

32

Secondary mandrel

33

Blow channel

34

Return channel

35

inclined compressed air outlet

36

Pinch edge gap

50

canister

51

Topsoil

52

inner space

53

Handle

54

Support

55

External thread

56

upper degree

57

Ventilation duct

58

horizontal section

59

vertical section

60

outer duct wall

61

inner duct wall

62

Main opening

63

Ventilation opening

64

Outer surface

100

arrangement

101

Blow head

102

tube

103

Separator

104

Entry opening

105

Blowing position

106

Preform

110

vertical

111

horizontal

Claims (11)

A method for producing a canister (50) made of plastic, comprising the following steps: • Continuously extruding a hose (102), • Positioning an open blow mold (1) around the hose (102) so that the hose (102) is between the two Blow mold halves (2) are located, • close a hose gripper (3) arranged on the blow mold (1) to clamp the hose (102) and at the same time keep the hose (102) open on its upper side to form an entry opening (104), • separate the hose (102) above the tube gripper (3) to form the preform (106), • horizontal movement of the blow mold (1) together with the preform (106) suspended therein and held by the tube gripper (3) in a blowing position (105), • retraction of a blow pin arrangement (30) from above into the entry opening (104) of the preform (106), • closing the blow mold halves (2), • inflating the preform (106) in the blow mold (1) into a canister (50), • whereby the Sc hose gripper (3) comprises at least one gripping element (4) on each blow mold half (2), wherein the hose (102) can be clamped between the gripping elements (4), • characterized in that the gripping elements (4) in the closing direction by means of springs (6) are spring-loaded, the springs (6) being relaxed to clamp the hose (102), the springs (6) being tensioned when the blow mold halves (2) are closed, and the springs (6) in the tensioned state are maintained. Procedure (59) according to Claim 1 , • wherein the canister (50) has a nozzle (54) for pouring in and out, • wherein a vertical section (59) of a ventilation channel (57) of the canister (50) protrudes into the nozzle (54), • wherein the blow pin arrangement (30) when the blow mold halves (2) are closed with a main blow pin (31) for the nozzle (54) and with a secondary blow pin (32) for the vertical section (59) of the ventilation channel (57). Method according to one of the preceding claims, wherein the hose gripper (3) clamps the hose (102) with two gripping areas (5) at two points spaced apart from one another, so that the entry opening (104) has an oval cross-section. Procedure according to Claim 3 , the two gripping areas (5) being moved towards one another after being clamped in order to change the shape of the entry opening (104). Method according to one of the preceding claims, wherein compressed air is blown into the preform (106) before the blow mold halves (2) are closed in order to pre-blow the preform (106); preferably via at least one compressed air nozzle on at least one of the gripping elements (4). Procedure according to Claim 5 wherein the preform (106) is inflated during the pre-blowing beyond the internal shape dimension of the blow mold (1). Method according to one of the preceding claims, wherein the blow pin arrangement (30) is moved horizontally after it has been moved into the entry opening (104) and before the blow mold halves (2) are closed. Method according to one of the Claims 2 to 7th The secondary blowing mandrel (32) has at least one obliquely arranged compressed air outlet (35) on its underside and material is blown away when the canister (50) is inflated via this compressed air outlet (35) to support the shaping of the ventilation channel (57). Blow mold (1) for producing a canister (50) made of plastic, in particular for carrying out the method according to one of the preceding claims, comprising: • two blow mold halves (2), shaping the canister (50), • and a hose gripper (3) with at least one gripping element (4) on the top of one blow mold half (2) and at least one opposing gripping element (4) on the top of the other blow mold half (2), • wherein the gripping elements (4) can be moved relative to the blow mold half (2), so that a disposed between the open blow mold halves (2), hose (102) is clamped by the gripping elements (4), without closing the blow mold halves (2), • characterized by at least one spring (6) per gripper element (4), the gripping element, the (4) acted upon in the closing direction, and a holding device (7) designed to hold and release the spring-loaded gripping element (4). Blow mold after Claim 9 , the hose gripper (3) having two gripping areas (5), each for clamping the hose (102), the two gripping areas (5) being spaced from one another to form an entry opening (104) in the hose (102). Blow mold according to one of the Claims 9 or 10 wherein the two gripping areas (5) can be moved towards one another in order to change the shape of the entry opening (104).

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