WO2004073957A1

WO2004073957A1 - Method and device for producing seamless shaped hollow bodies

Info

Publication number: WO2004073957A1
Application number: PCT/EP2004/001740
Authority: WO
Inventors: Guenther Wenger
Original assignee: Etimex Technical Components Gmbh
Priority date: 2003-02-24
Filing date: 2004-02-21
Publication date: 2004-09-02
Also published as: DE10308446A1

Abstract

The aim of the invention is to improve a method for producing seamless shaped hollow bodies, during which a parison (552) is inserted into a mold in an insertion area, is moved along a transport path, which is essentially defined by a recess of the mold, through the recess, and up to an exit area of the mold, so that the parison can be easily and reliably moved through the mold. To this end, the invention provides that, between the insertion area and the exit area inside the recess, at least one fluid flow consisting of a fluid is directed against the inserted parison. In addition, at least one flow component of the at least one fluid flow points in the direction of the transport path directed from the insertion area to the outlet area. The invention also relates to a device for carrying out a method of this type.

Description

Method and device for producing seamless hollow moldings

The invention relates to a method for producing seamless hollow moldings, in which a preform is introduced into a mold in an insertion region, is moved through the recess along a transport path essentially defined by a recess in the mold, and is guided to an outlet region of the mold.

The invention further relates to a device for producing seamless hollow moldings, in particular for carrying out the above-mentioned method, the device comprising a mold with an insertion area for inserting a preform into a recess in the mold and with an outlet area for leading the preform out of the recess a transport device for moving the preform through the recess along a transport path defined by the recess.

A generic method and a generic device are known for example from WO 01/58672 AI. It describes how to guide a preform through a blow mold in that a gas flows around the tubular preform on its outside and thereby prevents sticking to an inner wall of the mold. For this purpose, the gas is introduced into the insertion area from outside the mold by means of an annular injector. In order to ensure optimal functionality, it is necessary that the injector arranged outside the insertion area is optimally adjusted. In other known methods, the movement of the preform is supported by the mold, in that a negative pressure is generated in the outlet area in relation to the insertion area, so that the preform is sucked through the mold.

It is therefore an object of the present invention to improve a method and a device of the type described at the outset in such a way that the preform can be easily and safely moved through the mold.

This object is achieved according to the invention in a method of the type described at the outset in that at least one fluid stream formed from a fluid is directed against the introduced preform between the introduction region and the outlet region within the recess, and in that at least one flow component of the at least one fluid stream in the direction of the Entry area to the exit area directed transport path points.

Developing the known method in this way has the advantage that optimal guidance of the preform is ensured through the entire shape. At the same time, forces can be exerted on the preform in the direction of the transport path along the entire transport path by the fluid flow, so that it can be moved through the mold much more easily than in previously known methods.

The method becomes particularly simple if the at least one fluid stream is generated by a gas or a gas mixture, in particular by air. The method can then also be used in open systems using ambient air. In an advantageous variant of the method, a transport direction is defined for each point of the transport route by applying a tangent to the transport route or the recess. If the direction of transport is known, the at least one fluid flow can be optimally directed onto the preform.

In order to be able to produce almost any mold hollow body, it is advantageous according to a further preferred form of the method if a mold with a recess having at least one curvature is used, in particular with a multi-axis.

It is advantageous if a hollow mold comprising at least two molded parts is used as the mold, if at least one of the at least two molded parts at least partially surrounds the recess and if, in a closed position of the at least two molded parts, in which they bear directly or indirectly on one another, the Recess forms a mold cavity. By using at least two mold parts, the mold can be opened after the production of a mold hollow body and the mold hollow body can be removed in a simple manner. In addition, complicated hollow shapes can also be formed in this way.

So that a preform can also be inserted into a mold, the at least two molded parts of which assume the closed position, it is advantageous if a mold cavity is used which has an inlet opening in the closed position and / or an outlet opening in the outlet region. Shapes that are completely closed on both sides or on one side are thus also conceivable. It is favorable if the mold cavity is formed by bringing the at least two mold parts together before the preform is introduced. The preform can thus be introduced into the mold cavity in a targeted manner through an opening.

Particularly when a preform is to be introduced into a substantially horizontal recess in a molded part, it is advantageous if the mold cavity is formed by bringing the at least two molded parts together after inserting the preform into one of the at least two molded parts. The mold is therefore only closed when the preform is inserted into the recess of a molded part. This also makes it possible to check whether the preform lies in the desired manner in the molded part before the mold is closed.

So that the preform can be brought into its final shape, for example by inflation, the insertion area and the exit area of the mold are closed after the preform has been fully inserted into the mold.

In order to apply a fluid to the preform in a particularly simple manner, according to a preferred form of the method, at least one molded part of the at least two molded parts is provided with at least one fluid outlet opening, and the at least one fluid flow is caused by the application of fluid to the at least one fluid outlet opening generated towards the recess. Depending on the shape of the mold, one or more molded parts can thus be provided with fluid outlet openings. In particular, in certain areas of the mold, fluid outlet openings are arranged to optimize movement of the preform through the mold.

It is advantageous if the preform is introduced into the mold essentially parallel to the direction of gravity. This eliminates the need for further process steps that support the insertion of the preform into the mold.

In the case of complicated shapes, however, it can also be advantageous if the preform is introduced into the hollow mold at an angle between 0 ° and 90 ° or essentially transversely to the direction of gravity. For example, in the case of open molds, into which the preform is first inserted into the recess of a molded part and then the mold is closed, the preform can be inserted into the mold particularly safely and gently.

In order to avoid the preform sticking to the mold, it is advantageous if the at least one fluid stream flows continuously.

Transporting the preform through the mold can additionally be improved if the at least one fluid stream flows discontinuously, in particular pulsatingly. In this way, the preform is virtually shaken through the mold.

It would be conceivable to only let the fluid flow flow continuously or only pulsatingly. According to a preferred form of the method, however, it can also be provided that the at least one fluid flow flows discontinuously during the introduction of the preform into the mold, and continuously after the complete introduction into the mold. In principle, the fluid flow can be directed against the preform at any angle. However, in order to achieve optimal transport of the preform through the mold, a flow direction of the at least one fluid stream before the impingement hits the preform with the transport path and / or the transport direction forms an angle in the range from 10 ° to 60 °, in particular in the range of 15 ° to 30 °, preferably 20 °. The larger the included angle, the better a distance is maintained between the preform and the mold. In contrast, as the angle becomes smaller, the transport of the preform is facilitated by the shape.

In the case of particularly strongly curved recesses, the risk of the preform coming into contact with the mold cavity is particularly great. In order to minimize this risk, it can be advantageous if at least one spacer fluid flow is directed against the preform substantially transversely to the transport path when the minimum curvature radius of the transport path is undershot. In this way, the entire energy of the spacer fluid flow is used to maintain a distance between the preform and the mold cavity.

In order to bring the preform into its final shape, the preform is filled up, in particular with a fluid, preferably with compressed air, after the insertion region and the outlet region of the closed mold cavity have been closed. As a result, the tubular preform, which is soft during insertion, is pressed against the mold cavity, so that it takes on its shape and also maintains it after cooling. In order to obtain a particularly smooth and bubble-free surface of the finished mold cavity, the mold cavity is vented during the inflation of the preform, in particular by removing a fluid filling the mold cavity through at least one emptying opening of the mold cavity. If, for example, there is still air in the mold cavity between its inner wall and the preform, it can be trapped when the preform is inflated and, in the worst case, there is some distance between the preform and the wall of the mold cavity. This could result in deviations in the dimensions of the hollow moldings produced. This is avoided by venting the mold cavity.

The implementation of the method and the construction of a device used for this purpose are particularly simple if the at least one fluid outlet opening forms the at least one emptying opening. This means that a fluid stream first flows through the fluid outlet opening to transport the preform through the mold and to prevent it from sticking to the mold. As soon as the preform has been inserted into the mold in the desired manner, the mold cavity can be emptied through the fluid outlet openings, which then act as drainage openings, in particular as ventilation openings, for example without or by applying a vacuum to the fluid outlet openings.

With some molds, difficulties arise when inserting the preform into the mold through the insertion area. This can be remedied if an insertion aid is used to insert the preform through the insertion area of the mold. The method becomes particularly simple if the insertion aid comprises a sliding surface inclined towards the insertion region, in particular one molded onto the at least one molded part. If the preform does not hit the mold cavity directly, it is inserted into the mold through the sliding surface without any additional aids.

Depending on the molded part to be produced, it may be necessary for the preform to protrude a little from the insertion area and / or from the exit area after being inserted into the mold. In this case, it is advantageous if the preform is guided in a guided manner into the insertion area in an insertion direction and / or out of the outlet area in an exit direction and / or that the supported preform is transported in a forced manner. In this way, uncontrolled movements of the preform can be avoided; in particular, the preform can be prevented from collapsing.

So that the preform does not necessarily have to be introduced into the mold in the direction of gravity, which would possibly result in a complex reorientation of the mold, in a preferred form of the method the preform is brought to the mold in an ejection direction specified by a preform production device and from the ejection direction in redirected the direction of insertion. This can be achieved, for example, in a simple manner using a transport rail or a gripper, which can itself be moved. In any case, one end of the preform emerging from the preform production device is brought into the insertion direction, so that the preform can be inserted into the mold particularly easily.

In order to produce special shapes, the preform has to be completely passed through the mold and has to be removed a little from it, before it is brought into its final form. It is therefore expedient if the preform is guided out of the hollow mold in the direction of execution and is transported and / or supported in a substantially forced manner in the exit direction. This can ensure that the preform initially retains its shape before it is brought into its final shape, for example bent.

A particularly gentle transport of the preform is obtained if it is transported outside the mold before it is introduced and / or after it is removed from the mold by applying at least one transport fluid stream, in particular a gas stream, and if the at least one transport fluid stream is at least one has flow component pointing in the direction of transport. In this way, the preform can slide out of the mold on a fluid cushion, for example an air cushion, and can continue to slide a part in the desired manner.

The object stated at the outset is achieved according to the invention in a device of the type described at the outset in that the transport device comprises at least one flow generating means for generating at least one fluid flow which can be directed against a preform and is formed by a fluid, so that at least one flow component of the points at least one fluid flow in the direction of the transport path directed from the insertion region to the outlet region.

No additional aids are required for transporting the preform through the mold in the device proposed according to the invention. In particular, no elements to be arranged on the outside of the mold are required, so that the structure of the mold is particularly simple and compact, since the transport device is integrated directly into the mold. Fluid flows can be generated particularly easily if the fluid is a gas or a gas mixture, in particular air. Open systems can thus be formed, in which air is sucked in from the surroundings of the device, directed against the preform and led out of the mold again.

A transport direction can preferably be defined for each point of the transport path by applying a tangent to the transport path or the recess. The direction of transport can be determined particularly easily, and accordingly the at least one flow generating means can be arranged and aligned in such a way that the fluid flow directed against the preform optimally transports the preform through the mold.

So that any shape hollow body can be produced, it is advantageous if the recess of the shape is curved, in particular multi-axis curved.

In order to be able to remove finished molded hollow bodies from the mold in a simple manner, it is advantageous if the mold is a hollow mold comprising at least two molded parts and if the recess defines a mold cavity in a closed position in which the at least two molded parts bear directly or indirectly on one another , In addition, individual parts, for example molded parts of the mold, are easier to manufacture, are smaller and lighter. In addition, more complicated shapes can be realized.

According to a preferred embodiment of the invention, it can be provided that the mold cavity has an inlet opening in the closed position in the insertion region and / or an outlet opening in the outlet region. This allows a preform to be inserted into the mold when it is in the closed position.

It is advantageous if the mold can be brought into the closed position by bringing the at least two molded parts together before inserting the preform. As a result, the preform is guided particularly well during insertion and transport through the mold.

In the case of particularly complicated molds, however, it can be advantageous if the mold can be brought into the closed position by bringing the at least two molded parts together after inserting the preform into one of the at least two molded parts. This configuration allows the preform to be inserted into a recess in a molded part and then to close the mold.

So that the mold cavity can be completely closed even when the inlet openings and / or outlet openings are provided, it is advantageous if closure elements are provided for closing the insertion region, in particular the inlet opening, and the outlet region, in particular the outlet opening.

A particularly preferred variant of the device results if the transport device comprises at least one fluid outlet opening directed towards the recess and if the at least one fluid outlet opening is arranged on at least one of the at least two molded parts and if the at least one fluid flow can be generated by acting on it the at least one fluid outlet opening with the fluid in the direction of the recess. This results in a particularly simple structure of the device, because, for example, holes through the Form through, which end in the region of the recess in order to direct the fluid flows required for transporting a preform onto the preform. It is not necessary that all molded parts are provided with fluid outlet openings. For example, in the case of a two-part mold, which is only closed after a preform has been inserted, it may be sufficient if fluid outlet openings are provided in the molded part, into which the preform is first inserted.

A particularly good fluid flow can be achieved if the at least one fluid outlet opening is a nozzle. Using the known flow laws, particularly high flow velocities can be achieved.

In principle, the insertion area could be arranged so that it is inclined against the direction of gravity. However, it is advantageous if the insertion area is arranged such that the preform can be introduced into the hollow mold essentially parallel to the direction of gravity. In this case, additional aids for inserting the preform into the mold are not required.

Depending on the shape of the molded hollow body to be produced, it can, however, be advantageous if the insertion area is arranged in such a way that the preform can be inserted into the mold at an angle between 0 ° and 90 ° or essentially transversely to the direction of gravity. Such an arrangement is chosen, for example, if the preform is first introduced into a molded part and the mold is only closed after the preform has been introduced by bringing the first molded part together with other molded parts.

A particularly gentle transport of the preform through the mold is achieved if at least one continuous ier flowing fluid flow can be generated. This can be achieved, for example, by means of a compressed air generating device.

In particular in the case of narrow and multiply curved, complicated mold cavities, it is advantageous if at least one discontinuously flowing fluid stream, in particular a pulsating fluid stream, can be generated with the flow generating means. The preform is virtually shaken through the mold by exposure to a discontinuously flowing fluid stream.

In order to achieve particularly flexible transport properties of the transport device, it is advantageous if the flow generating means can alternately generate a continuous or a discontinuous gas stream.

An optimal transport of the preform through the mold with the least possible energy expenditure for the transport can be achieved in a favorable manner if the at least one fluid outlet opening is arranged in such a way that a flow direction of the at least one gas stream with the transport path or the transport direction unites before it hits the preform Includes angles in the range from 10 ° to 60 °, in particular in the range from 15 ° to 30 °, preferably 20 °.

It is advantageous if at least one fluid outlet opening is provided in the form of a spacer nozzle and is arranged in such a way that at least one spacer fluid flow can be directed onto the preform substantially transversely to the transport path when the transport path falls below a minimum radius of curvature. In this way, even in the case of particularly strongly curved mold cavities, the preform can come into contact with an inner wall of the mold cavity, in particular with an inner arch, are practically excluded.

It is expedient if the spacing nozzle is arranged in the region of a curvature of the recess, pointing away from the center of curvature in the direction of the mold cavity. As a result, a fluid flow can be directed in a simple manner transversely to the transport path onto a preform to be transported in the mold cavity.

In order to bring the preform into its final shape after it has been introduced into the mold, it is advantageous if a blowing device is provided for inflating the preform with a fluid after the insertion area and the exit area have been closed, in particular with a gas or gas mixture , preferably with air.

In order that the surface of the mold hollow body to be produced is particularly smooth and the body itself is always uniformly shaped, an emptying device is preferably provided for emptying the mold cavity during the inflation of the preform.

For a particularly smooth surface, it is advantageous if the emptying device comprises at least one emptying opening for removing a fluid contained in the mold cavity and surrounding the preform. The fluid, for example a gas, preferably air, can then escape from the mold cavity through the ventilation openings which form drain openings.

A particularly simple structure of the shape is obtained if the at least one fluid outlet opening forms the at least one drain opening. The fluid outlet opening can thus be used twice. On the one hand can by means of which a fluid flow is directed against the preform during the introduction of the preform into the mold, on the other hand the mold cavity can be vented through the fluid outlet opening during the inflation of the preform.

So that the preform can be inserted into the mold in a simple manner, an insertion aid for inserting the preform into the mold in the insertion region can be provided in a particularly preferred embodiment.

A particularly simple design of the insertion aid is obtained if it comprises a sliding surface inclined towards the recess, in particular one molded onto the at least one molded part. No other aids are required to insert the preform into the mold.

Depending on the shape of the mold cavity, it is necessary that the preform still protrudes from the insertion area and / or from the exit area and must be brought into its final shape. So that it does not hang loosely and, in the worst case, can collapse, it is advantageous if at least one transport unit is provided for holding and / or transporting the preform outside of the mold before it is introduced into the insertion area and / or after it has been removed the exit area.

It is advantageous if, with the at least one transport unit, the preform can be picked up in an ejection direction specified by a preform production device and can be deflected into the insertion direction different from the ejection direction. The transport unit thus has a double function, on the one hand it holds and / or transports the preform, on the other hand it also serves as a deflection device with which the tion on the transport unit preform can be deflected in a second, different direction, for example for inserting the preform into the mold.

According to a further preferred embodiment of the invention, provision can be made for the preform to be able to be guided out of the hollow mold in the execution direction with the at least one transport unit and for further transport and storage essentially in the execution direction. The parallel alignment of the transport unit, for example a transport rail, ensures particularly good transport of the preform.

In principle, the transport unit could be provided with rollers or other means on which the preform can be moved without great resistance. However, it is particularly advantageous if the transport unit comprises at least one transport fluid flow application device for supplying the preform with a transport fluid flow, which may have a flow component pointing in the transport direction. This configuration enables the preform to slide along on a fluid cushion and to be moved on the transport unit essentially without contact. The use of a gas or gas mixture, in particular air, enables a particularly simple construction.

The following description of preferred embodiments of the invention serves in conjunction with the drawing for a more detailed explanation. Show it:

Figr 1: a first embodiment of a blow molding system; Figure 2: a second embodiment of a blow molding system;

Figure 3: a third embodiment of a blow molding system with a deflection rail;

Figure 4: a fourth embodiment of a blow molding system with a transport rail; and

Figure 5: a fifth embodiment of a blow molding system with a deflection and a transport rail.

FIG. 1 shows a blow molding system, generally provided with the reference number 100, which comprises a main mold part 104 consisting of two mold halves 102. A recess 106 is machined into each of the two mold halves 102, which, when the mold halves 102 are assembled, form a multi-axis and / or multi-axis curved mold cavity 108, which specifies the shape of a blow molding, not shown. An insertion opening provided with an edge 110 that tapers conically in the direction of the mold cavity 108 and an outlet opening of the mold cavity 108 can be closed, for this purpose each mold half 102 is equipped with a slide 116 closing the insertion opening 112 and with a slide 118 closing the outlet opening 114 are provided, which are each slidably supported by a drive 120 or 122 transversely to an insertion direction 124 and transversely to an outlet direction 126 of a preform 152 into the mold cavity 108 or out of it.

Furthermore, the two mold halves 102 are provided with a multiplicity of bores 128 which extend into the recesses 106. Through openings of the holes 128 are in the form of transport nozzles 130 or Spacer nozzles 132 designed. The transport nozzles 130 are arranged such that they or the flow direction 131 of gas flowing through the transport nozzles 130 into the mold cavity 108 with a tangential plane 136 abutting the recess 106 form a transport angle 134 of approximately 45 °. The spacer nozzles 132 are arranged on inner arches 138 of the mold cavity 108 in such a way that they or the flow direction of gas flowing into the mold cavity 108 through the spacer nozzles 132 form a spacing angle 142 of approximately 90 ° with a tangential plane 140 abutting the inner arch 138.

A blow mandrel 146 arranged on a drive unit 144 can be inserted with closed slides 116 through a blow mandrel guide 148 provided in the form of a bore.

To produce blow moldings which are curved once or several times, the main mold part 104 is brought into the vicinity of an extruder head 150 of an extruder, not shown in the figures, with which the tubular preform 152 made of plastic can be extruded. In the blow molding system 100, the main mold part 104 is oriented relative to the extruder head 150 such that the preform 152 leaves the extruder head 150 in the direction of gravity 154 and can enter the insertion opening 112 directly, possibly supported by the conical edge 110.

FIG. 2 shows a blow molding system, which is generally provided with the reference number 200. It essentially corresponds to the blow molding system 100 from FIG. 1. Therefore, identical elements of the blow molding system 100 and 200, like all the other blow molding systems described, are provided with reference numerals, the last two digits of which correspond. Unlike the blow molding system 100, the blow molding system 200 has a drive unit 244 on which a blow mandrel 246 is arranged and which, contrary to the direction of execution 226, is provided by a blow mandrel guide 248 in the form of a bore arranged on the sliders 218 after closing the outlet opening 214 by means of drives 222 driven slide 218 can be pushed into the mold cavity 108.

The two blow molding machines 100 and 200 can be used to produce seamlessly blown hollow bodies, which can also be multi-axis curved. For a simple explanation, a manufacturing method according to the invention is described below using the blow molding system 100, which can also be carried out essentially identically on the blow molding system 200.

In a first step, the main mold part 104 is closed by bringing the two mold halves 102 together, so that the curved mold cavity 108 is formed. The slides 116 and 118 are in their open position, that is to say both the insertion opening 112 and the outlet opening 114 are each not closed. The preform 152 is extruded from the extruder head 150 and moves due to its weight in the direction of gravity 154 through the insertion opening 112. If the preform 152 does not optimally meet the insertion opening 112, the edge 110 serves as an insertion aid.

In order to transport the preform 152 as easily and gently as possible through the mold cavity 108, the transport nozzles 130 and the spacer nozzles 132 are pressurized with compressed air by a compressed air supply, not shown, to which they are connected, optionally continuously or also pulsed. The spacer nozzles 132 serve to keep the preform spaced from the inner arches 138. The compressed air impinging on the preform 142 from the transport nozzles 130 at an angle of 10-25 ° relative to the tangential plane 136 pushes the tubular preform 152 through the mold cavity 108. The tangential plane 136 runs essentially parallel to a transport path 137 which extends from the inlet opening 112 to the outlet opening 114. Two effects of flowing gases are used. On the one hand, the preform 152 is moved in the transport direction by the flow component of the compressed air escaping through the transport nozzles 130, which flow component essentially points parallel to the tangential planes 136 and 140. On the other hand, the air flowing in the transport direction outside the preform 152 creates a negative pressure in the mold cavity 108 with respect to the interior of the preform 152, so that the preform 152 is pulled towards the inner wall of the mold cavity, whereby it retains its tubular shape and not in itself coincides.

As soon as the preform 152 protrudes through the outlet opening 114, the extrusion process is stopped, the preform 152 is cut off in the region of the insertion opening 112 and the insertion opening 112 and the outlet opening 114 are closed with the slides 116 and 118.

In order to bring the preform 152 into its final shape, the blow mandrel 146 is inserted through the blow mandrel guide 148 into the interior of the mold cavity 108 and air is blown into the interior of the preform 152. Air is no longer blown into the interior of the mold cavity 108 by the transport nozzles 130 and the spacer nozzles 132 during the inflation of the preform 152 resting in the mold cavity 108, but both types of nozzle serve for ventilation, that is to say that air contained in the mold cavity is caused by the Transport nozzles 130 and / or can exit through the spacer nozzles 132. As a result, a particularly good surface of the hollow mold body to be produced can be obtained.

After the preform 152 has been inflated and cooled, the blow mandrel 146 is retracted and the insertion opening 112 and the outlet opening 114 are released again by the slides 116 and 118. The second mold halves 102, not shown in FIG. 1, are moved away from the first mold half 102, so that the finished molded part can be removed from the mold half 102.

The blow molding machine 200 can be used to produce corresponding molded parts. However, in the blow molding system 200, the preform 152 which is completely inserted into the main mold part 104 is inflated from the outlet opening 114, specifically by inserting the blow mandrel 246 through the blow mandrel guide 248 into the mold cavity 108 against the direction of execution 226.

FIG. 3 shows a third variant of a blow molding system, which is generally provided with the reference number 300. It comprises two mold halves 302, of which only one, namely the lower one, is shown in FIG. 3. This is provided with a depression 306 which runs essentially horizontally, that is to say in a plane perpendicular to the direction of gravity 354. In order to be able to insert the preform 352, which leaves the extruder head 350 in the direction of gravity 354, into the recess 306 in the insertion direction 324, that is to say transversely to the direction of gravity 354, a curved, essentially U-shaped deflection rail 360 is provided. To receive the preform 352 from the extruder head 350, a receiving end 362 of the deflection rail 360 points counter to the direction of gravity 354. An insertion 364 of the deflection rail 360 extends parallel to the insertion direction 324 into the recess 306 at an end opposite the outlet opening 314. Overall, the deflection rail 360 thus forms a 90 ° angle. Arranged on the deflection rail 360 are a plurality of nozzles 366 connected to a compressed air supply (not shown), through which compressed air can flow continuously or discontinuously, in particular pulsed, in the direction of the preform 352 guided by the deflection rail 360. The air conducted through the nozzles 366 forms an air cushion on which the preform 352 can slide into the depression 306. In the depression 306 it is transported through the depression 306 to the outlet opening 314 by means of transport nozzles 330, which are arranged in the manner described in connection with the blow molding systems 100 and 200, that is to say at an angle to the transport direction. The preform 352 is advantageously shaken through the recess 306 by pulsed compressed air supply.

Before the front end of the preform 352 reaches the outlet opening 314, the preform 352 is gripped and held in the region of the extruder head 315 by a gripper arm 368. The preform 352 is then cut between the gripper arm 368 and the extruder head 350. As soon as the gripper arm 368 has gripped and holds the preform 352, the deflection rail 316 is no longer required. It is then moved out of the area of the mold half 302 by means of a drive unit 370, for example linearly displaced or pivoted. As soon as the deflection rail 360 is removed, the gripping arm 368 is pivoted along a pivoting path 372 which essentially describes a quarter circle, so that the end of the preform 352 held by the gripping arm 368 is completely inserted into the depression 306, in particular inserted. When the preform 352 is separated, the total length of the preform 352 is selected so that after the gripping arm 368 has been pivoted, the front end of the preform 352 just reaches the outlet opening 314. For blow molding the preform 352, a second mold half 302 is moved over the mold half 302 shown in FIG. 3 and the mold cavity 308 is closed. The outlet opening 314 is then closed by means of two slides 318, and a blow mandrel 346, which is provided on the sliders 318, introduces a blow mandrel 346, which is moved against the direction of execution 326 by the drive unit 344, into the mold cavity 308.

Air is then blown into the interior of the preform 352 by the blow mandrel 346, so that the latter is pressed against the inner wall of the mold cavity 308. To vent the mold cavity 308, the transport nozzles 330 are used as vent openings, as a result of which a particularly good surface area of the blow-molded hollow body can be achieved.

The deflection rail 360 described in connection with the blow molding system 300 can of course also be used in connection with the blow molding systems 100 and 200 if their main mold parts 104 and 204 are oriented in such a way that the insertion directions 124 and 224 do not run parallel to the direction of gravity 154 or 254.

A fourth variant of a blow molding system, which is provided overall with the reference number 400, is shown in FIG. 4. Its essential components correspond to the blow molding system 200. Compared to this, however, it differs in the area of the outlet opening 414. An elongated transport rail 476 is provided there, the cross section of which is essentially U-shaped. It is provided with a large number of nozzles 478 connected to a compressed air supply, not shown, through which compressed air can be passed continuously or discontinuously, ie in particular also in a pulsed manner. The slightly inclined transport Rail 476 is held by a drive unit 480 with which it can be moved away from the outlet opening 414, for example pivoted away. When the outlet opening 414 is open, the transport rail 476 is arranged such that the preform 452 emerging from the mold cavity 408 can slide on the transport rail 476 in the direction of its free end 482. In the area of the free end 482 a gripping arm 484 is arranged, which carries a detector 486 in the form of a photodiode, with which it can be detected when the front end of the preform 452 protrudes over the free end 482 of the transport rail 476 and is gripped by the gripping arm 484 can.

With the gripper arm 484, the front end of a preform 452 held thereon can be pivoted along a swivel path 488, so that the free end of the preform 452 points in an end position essentially against the direction of gravity 454. On the mold halves 402, linearly displaceably mounted slide 490 can be displaced transversely to the direction of execution 426 via the preform held by the gripping arm 484, so that the free end of the preform 452 pointing against the direction of gravity 454 is completely enclosed. A blow mandrel 446 arranged on a drive 444 can be passed parallel to the direction of gravity 454 through a blow mandrel guide 448 of the slide 490, to the extent that it extends into the mold cavity 408 and into the interior of the preform 452.

The manufacture of a blow molded part until the preform 452 emerges from the mold cavity 408 corresponds to the method described in connection with the blow molding system 200, ie the main mold part 404 is closed before the preform 452 is inserted, the preform 452 through the insertion opening 412 into the mold cavity 408 introduced and by means of compressed air supply to the transport nozzles 430 and the spacer nozzles 432 moved through the mold cavity 408 until it emerges from the outlet opening 414 and is received by the transport rail 476. If the end of the preform is detected by means of the detector 486, the preform 452 is gripped with the gripping arm 484 and pivoted upward against the direction of gravity 454 and held until the slide 490 mounted on the mold halves 402 holds the free end of the preform 452 and Close or close outlet opening 414. The insertion opening 412 is closed by means of the slide 416. After the blowing mandrel 446 has been introduced into the interior of the mold cavity 408, air is blown into the interior of the preform 452, so that it is pressed against the inner wall of the mold cavity 408. The mold cavity 408 is vented via the transport nozzles 430 and the spacer nozzles 432. After the main mold part 404 has cooled, the two mold halves 402 are separated from one another and the finished molded part can be removed.

The transport rail 476 provided in connection with the blow molding system 400 can also be used in connection with other blow molding systems, in particular it is not a requirement that transport nozzles 430 and spacer nozzles 432 are provided for transporting the preform 452 through the mold cavity 408. It would also be possible to transport the preform 452 through the mold cavity 408 by suction at the outlet opening 414, that is, to use the transport rail 476 also in connection with conventional suction blow molding systems and when carrying out known suction blow molding processes.

A blow molding system, provided overall with the reference numeral 500 in FIG. 5, combines the functions of the blow molding systems 100, 300 and 400. Transport nozzles 530 and spacer nozzles 532 are arranged in the interior of the two mold halves 502, as in all the blow molding systems already described above.

As in the blow molding system 400, a transport rail 576 is held by a drive unit 580 in the region of the outlet opening 514. The front end of the preform 552, which is detected by a detector 586, can be gripped by a gripper arm 584 and pivoted upward against the direction of gravity 554. With the slider 590, the main mold part 504 can be completely closed in the area of the outlet opening 514 surrounding the preform 552.

The insertion opening 512 is oriented transversely to the direction of gravity 550 in the blow molding system 500, similar to the blow molding system 300, so that the preform 552 extruded from the extruder head 554 can be deflected into the insertion direction 524 via a deflection rail 560 and introduced into the insertion opening 512. For easier transport of the preform 552, the deflection rail 560 is provided with nozzles 566 to which compressed air is applied. As soon as detector 586 detects the end of preform 552, gripper arm 568 detects the rear end of preform 552, which is then severed between gripper arm 568 and extruder head 550. The deflection rail 560 can then be removed with the drive unit 570 and the gripping arm 568 can be pivoted along the pivot path 572 such that the rear end of the preform 552 points downward in the direction of gravity 554. The rear end of the main mold part 504 and at the same time the preform 552 can then be completely closed with further sliders 592 similar to the sliders 590. As soon as the preform 552 is completely enclosed by the main mold part 504 and the slides 590 and 592, a blow mandrel 546 arranged on a drive unit 554 is moved upward into the mold cavity 508 and into the interior of the mold cavity 508 by a blow mandrel guide 548 arranged on the sliders 592 against the direction of gravity 554 Preform 552 introduced. Subsequently, air is blown through the blow mandrel 546 into the interior of the preform 552, so that the latter is pressed against the inner wall of the mold cavity 508. The mold cavity 508 can be vented through the transport nozzles 530 and spacer nozzles 532.

Both the transport rail 576 and the deflection rail 560 can also be used alone or together in connection with conventional blow molding systems, transport nozzles 530 inside the mold cavity 508 are not required for the functioning of the two rails. In particular, the combination of the described transport rails with conventional suction blowing devices is easily possible.

Claims

claims

1. A process for the production of seamless hollow moldings in which a preform is introduced into a mold in an insertion region, is moved through the recess along a transport path defined essentially by a recess in the mold and is guided to an outlet region of the mold, characterized in that between the insertion region and the outlet area within the recess is directed at least one fluid flow formed from a fluid against the inserted preform and that at least one flow component of the at least one fluid flow points in the direction of the transport path directed from the insertion area to the outlet area.

2. The method according to claim 1, characterized in that the at least one fluid stream is generated by a gas or a gas mixture, in particular by air.

3. The method according to any one of claims 1 or 2, characterized in that a transport direction is defined for each point of the transport path by applying a tangent to the transport path or the recess.

4. The method according to any one of the preceding claims, characterized in that a shape is used with a recess having at least one curvature, in particular with a multi-axis curved.

5. The method according to any one of the preceding claims, characterized in that a mold comprising at least two mold parts is used as a mold, that at least one of the at least two mold parts at least partially includes the recess and that in a closed position of the at least two mold parts, in which they directly or rest indirectly against one another, the recess forms a mold cavity.

6. The method according to claim 5, characterized in that a mold cavity is used which has an inlet opening in the closed position in the insertion region and / or an outlet opening in the outlet region.

7. The method according to any one of claims 5 or 6, characterized in that the mold cavity is formed by merging the at least two mold parts before inserting the preform.

8. The method according to any one of claims 5 or 6, characterized in that the mold cavity is formed by merging the at least two molded parts after inserting the preform into one of the at least two molded parts.

9. The method according to any one of the preceding claims, characterized in that the insertion area and the exit area of the mold are closed after the preform has been completely inserted into the mold.

10. The method according to any one of claims 5 to 9, characterized in that at least one molded part of the at least two molded parts is provided with at least one fluid outlet opening and that the at least one fluid flow is generated by acting on the at least one fluid outlet opening with the fluid in the direction of the recess out.

11. The method according to any one of the preceding claims, characterized in that the preform is introduced into the mold substantially parallel to the direction of gravity.

12. The method according to any one of claims 1 to 10, characterized in that the preform is introduced into the hollow mold at an angle between 0 ° and 90 ° or substantially transversely to the direction of gravity.

13. The method according to any one of the preceding claims, characterized in that the at least one fluid stream flows continuously.

14. The method according to any one of the preceding claims, characterized in that the at least one fluid stream flows discontinuously, in particular pulsating.

15. The method according to claim 14, characterized in that the at least one fluid stream flows discontinuously during the introduction of the preform into the mold, continuously after complete insertion into the mold.

16. The method according to any one of the preceding claims, characterized in that a flow direction of the at least one fluid stream before hitting the preform with the transport path and / or the transport direction an angle in the range of 10 ° to 60 °, in particular in the range of 15 ° to 30 °, preferably 20 °.

17. The method according to any one of the preceding claims, characterized in that when falling below a minimum radius of curvature of the transport path at least one spacer fluid flow is directed essentially transversely to the transport path against the preform.

18. The method according to any one of claims 9 to 17, characterized in that after the closing of the insertion region and the outlet region of the closed mold cavity, the preform is filled, in particular with a fluid, preferably with compressed air.

19. The method according to claim 18, characterized in that during the filling of the preform, the mold cavity is emptied, in particular by removing a fluid filling the mold cavity through at least one emptying opening of the mold cavity.

20. The method according to claim 19, characterized in that the at least one fluid outlet opening forms the at least one drain opening.

21. The method according to any one of the preceding claims, characterized in that an insertion aid is used to insert the preform through the insertion region of the mold.

22. The method according to claim 21, characterized in that the insertion aid comprises a sliding surface inclined towards the insertion region, in particular one molded onto the at least one molded part.

23. The method according to any one of the preceding claims, characterized in that the preform is guided supported in the insertion area in an insertion direction and / or out of the exit area in an exit direction and / or that the supported preform is transported in a forced manner.

24. The method according to claim 23, characterized in that the preform is brought to the mold in an ejection direction predetermined by a preform production device and is deflected from the ejection direction into the insertion direction.

25. The method according to any one of claims 23 or 24, characterized in that the preform is guided out of the mold in the direction of execution and / or transported and / or guided in a substantially forced manner in the exit direction.

26. The method according to any one of claims 23 to 25, characterized in that the preform is transported outside of the mold before being introduced and / or after it is led out of the mold by applying at least one transport fluid stream, in particular a gas stream, and that the at least one a transport fluid flow min at least has a flow component pointing in the transport direction.

27. A device for producing seamless hollow moldings, in particular for carrying out the method according to one of the preceding claims, wherein the device comprises a mold with an insertion region for inserting a preform into a recess of the mold and with an outlet region for leading the preform out of the recess a transport device for moving the preform through the recess along a transport path defined by the recess, characterized in that the transport device comprises at least one flow generating means (130, 132; 230, 232; 330; 430, 432; 530, 532) for generating at least one a fluid flow formed against a preform (152; 252; 352; 452; 552) introduced into the recess (106; 206; 306; 406; 506), so that at least one flow component of the at least one fluid flow in the direction of the from the insertion area (112; 212; 412; 512) to the exit riding area (114; 214; 314; 414; 514) directed transport route (137; 237; 337; 437; 537) points.

28. The apparatus according to claim 27, characterized in that the fluid is a gas or a gas mixture, in particular air.

29. Device according to one of claims 27 or 28, characterized in that for each point of the transport path (137; 237; 337; 437; 537) a transport direction can be defined by applying a tangent (136; 140; 236; 240; 336; 436; 440; 536; 540) to the transport path or the recess (106; 206; 306; 406; 506).

30. Device according to one of claims 27 to 29, characterized in that the recess (106; 206; 306; 406; 506) of the shape (104; 204; 304; 404; 504) is curved, in particular multi-axis curved.

31. Device according to one of claims 27 to 30, characterized in that the mold is a hollow mold (104; 204; 304; 404; 504) comprising at least two molded parts (102; 202; 302; 402; 502) and that the recess (106; 206; 306; 406; 506) in a closed position in which the at least two molded parts (102; 202; 302; 402; 502) bear directly or indirectly on one another, a molded cavity (108; 208; 308; 408; 508 ) Are defined.

32. Device according to claim 31, characterized in that the mold cavity (108; 208; 308; 408; 508) has an inlet opening (112; 212; 412; 512) in the closed position in the insertion area and / or an outlet opening (114; 214; 314; 414; 514).

33. Device according to one of claims 31 or 32, characterized in that the mold (104; 204; 404; 504) by bringing together the at least two molded parts (102; 202; 402; 502) before inserting the preform (152; 252 ; 452; 552) can be brought into the closed position.

34. Device according to one of claims 31 or 32, characterized in that the mold (304) by bringing together the at least two molded parts (302) after inserting the preform (352) into a nes of the at least two molded parts (302) can be brought into the closed position.

35. Device according to one of claims 27 to 34, characterized in that closure elements (116, 118; 216, 218; 318; 416; 490; 590; 592) for closing the insertion area, in particular the inlet opening (112; 212; 412; 512), and the outlet area, in particular the outlet opening (114; 214; 314; 414; 514), are provided.

36. Device according to one of claims 31 to 35, characterized in that the transport device at least one in the direction of the recess (106; 206; 306; 406; 506) directed fluid outlet opening (130, 132; 230, 232; 330; 430 , 432; 530, 532) and that the at least one fluid outlet opening (130, 132; 230, 232; 330; 430, 432; 530, 532) on at least one of the at least two molded parts (102; 202; 302; 402; 502 ) is arranged and that the at least one fluid flow can be generated by acting on the at least one fluid outlet opening (130, 132; 230, 232; 330; 430, 432; 530, 532) with the fluid in the direction of the recess (106; 206; 306 ; 406; 506).

37. Apparatus according to claim 36, characterized in that the at least one fluid outlet opening is a nozzle (130, 132; 230, 232; 330; 430, 432; 530, 532).

38. Device according to one of claims 27 to 37, characterized in that the insertion region (112; 212; 412) is arranged so that the preform (152; 252; 452) is substantially parallel to The direction of gravity (154; 254; 454) can be inserted into the mold (104; 204; 404).

39. Device according to one of claims 27 to 37, characterized in that the insertion region (512) is arranged so that the preform (352; 552) at an angle between 0 ° and 90 ° or substantially transversely to the direction of gravity (354; 554) can be inserted into the mold (304; 504).

40. Device according to one of claims 27 to 39, characterized in that with the flow generating means (130, 132; 230, 232; 330; 430, 432; 530, 532) at least one continuously flowing fluid stream can be generated.

41. Device according to one of claims 27 to 40, characterized in that with the flow generating means (130, 132; 230, 232; 330; 430, 432; 530, 532) at least one discontinuously flowing fluid stream, in particular a pulsating fluid stream, can be generated ,

42. Apparatus according to claim 41, characterized in that with the flow generating means (130, 132; 230, 232; 330; 430, 432; 530, 532) alternately a continuous or discontinuous gas flow can be generated.

43. Device according to one of claims 36 to 42, characterized in that the at least one fluid outlet opening (130; 230; 330; 430; 530) is arranged such that a flow direction (131; 231; 331; 431; 531) of the at least a gas flow before opening meet the preform (152; 252; 352; 452; 552) with the transport path (137; 237; 337; 437; 537) or the transport direction at an angle (134; 234; 334; 434; 534) in the range of 10 ° to 60 °, in particular in the range from 15 ° to 30 °, preferably 20 °.

44. Device according to one of claims 36 to 43, characterized in that at least one fluid outlet opening in the form of a spacing nozzle (132; 232; 432; 532) is provided and arranged such that when the minimum travel radius (137; 237; 437; 537) at least one spacer fluid flow can be directed onto the preform (152; 252; 452; 552) essentially transversely to the transport path (137; 237; 437; 537).

45. Apparatus according to claim 44, characterized in that the spacing nozzle (132; 232; 432; 532) in the region of a curvature (138; 238; 438; 538) of the recess (106; 206; 406; 506) pointing away from the center of curvature is arranged directed towards the mold cavity (108; 208; 408; 508).

46. Device according to one of claims 27 to 45, characterized in that a blowing device (144, 146; 244, 246; 344, 346; 444, 446; 544, 546) is provided for inflating the preform (152; 252; 352 ; 452; 552) with a fluid after closing the insertion area (112; 212; 412; 512) and the outlet area (114; 214; 314; 414; 514), in particular with a gas or gas mixture, preferably with air.

47. Apparatus according to claim 46, characterized in that an emptying device (130, 132; 230, 232; 330; 430, 432; 530, 532) is provided for emptying the mold cavity (108; 208; 308; 408; 508) while filling the preform (152; 252; 352; 452; 552).

48. Device according to claim 47, characterized in that the emptying device comprises at least one emptying opening (130, 132; 230, 232; 330; 430, 432; 530, 532) for removing an in the mold cavity (108; 208; 308; 408; 508) contained, surrounding the preform (152; 252; 352; 452; 552).

49. Apparatus according to claim 48, characterized in that the at least one fluid outlet opening (130, 132; 230, 232; 330; 430, 432; 530, 532) forms the at least one drain opening.

50. Device according to one of claims 27 to 49, characterized in that an insertion aid (110; 210; 410) for inserting the preform (152; 252; 452) into the mold (104; 204; 404) in the insertion area (112; 212; 412) is provided.

51. Device according to claim 50, characterized in that the insertion aid comprises a sliding surface (110; 210; 410) inclined towards the recess (106; 206; 406), in particular one molded onto the at least one molded part (102; 202; 402) ,

52. Device according to one of claims 27 to 51, characterized in that at least one transport unit (360; 460, 476; 576) is provided for supported guiding and / or forced transport of the preform (352; 452; 552) outside the mold ( 304; 404; 504) into the insertion area (412; 512) and / or out of the exit area (314; 414; 514).

53. Apparatus according to claim 52, characterized in that with the at least one transport unit (360; 560) the preform (352; 552) in an ejection direction predetermined by a preform production device (350; 550) (354; 554) can be received and in the the ejection direction (354; 554) different insertion direction (324; 524) can be deflected.

54. Device according to one of claims 52 or 53, characterized in that with the at least one transport unit (476; 576) of the preform (452; 552) in the execution direction (426; 526) from the hollow mold (404; 504) and can be transported and / or guided in an essentially forced manner in the direction of execution (426; 526).

55. Device according to one of claims 52 to 54, characterized in that the transport unit (360; 460, 476; 576) comprises at least one transport fluid flow application device (366; 466, 478; 578) for loading the preform (352; 452; 552) with a transport fluid flow which has a flow component pointing in the transport direction.