DEVICE AND METHOD FOR MANUFACTURING PLASTIC CONTAINERS WITH NON-CIRCULAR CROSS-SECTIONS

Description

[0001] The present invention relates to a device and a method for manufacturing plastic containers, and in particular plastic containers with non-circular cross-sections. Numerous devices and methods for manufacturing plastic containers are known from the prior art. These typically involve heating plastic preforms and forming them into containers using forming equipment such as blow molding machines (for example, stretch blow molding machines).

[0002] It is known from the prior art to also blow mold containers with cross-sections other than circular, such as oval cross-sections. This presents problems, as not only must blow molds with cross-sections deviating from circular be used, but alternative heating methods for the plastic preforms must also be employed.

[0003] In a heating method known from the prior art, a preferential heating process is used to heat plastic preforms for the production of non-cylindrical or insufficiently uniform containers. This method achieves a sinusoidal temperature distribution in the tangential direction along the plastic preform. Typically, two thermal maxima and two thermal minima, each opposite each other, are targeted.

[0004] WO2021122712A1 describes a device for manufacturing oval containers. In WO 20211 / 22712 A1, the crank pin serves to correctly align the turntable at the beginning of the heating process by passing between a set of two converging ramps arranged along the path of rotation of the turntables. The crank pin is thus automatically positioned upstream with respect to the direction of rotation of the turntables.

[0005] To produce oval containers of the required quality, the plastic preforms must be inserted into the blow mold in the correct orientation. This means that hot preform sides must align with long container sides, and cold preform sides with short container sides.

[0006] The applicant offers a Pro-Shape process for the production of such containers. In this process, the plastic preform is heated uniformly and then cooled on two sides of the preform using embossing plates. For both this process and the Preferential Heating process, the oriented insertion of the plastic preforms into the blow molds is mandatory.

[0007] The current state of the art presents several challenges. For example, maintaining a transfer angle of + / -10 degrees can be difficult. Furthermore, determining the rotational position of the plastic preforms can be very complex.

[0008] The present invention is based on the objective of proposing improved devices and methods for manufacturing containers with a non-circular cross-section according to claim 1.

[0009] This is achieved according to the invention by the subject matter of the independent claims. Advantageous embodiments and further developments are the subject matter of the dependent claims.

[0010] An inventive device according to claim 1 for manufacturing plastic containers has a heating device for heating plastic preforms, wherein the heating device has a transport device which transports the plastic preforms individually (i.e., in particular with a predetermined distance from each other) along a predetermined transport path, and this transport device has a plurality of holding devices for holding the plastic preforms, and at least one heating unit is provided which heats the plastic preforms, wherein at least one rotating device is provided which rotates the plastic preforms held by the holding devices with respect to their longitudinal directions during their transport through the heating device (and preferably at least temporarily during their heating).

[0011] Furthermore, the device has a forming unit which forms the plastic preforms transported by the heating unit into plastic containers, wherein this forming unit has at least one forming station which forms the plastic preforms into the plastic containers by applying a flowable and in particular gaseous medium.

[0012] Furthermore, the heating device has an adjusting device (or a rotational position adjustment device) which enables the adjustment of a rotational position of the plastic preforms, wherein preferably this adjusting device is arranged at least sectionally along the transport path of the plastic preforms.

[0013] It should be noted that the term "actuating device" is used below, but the corresponding device could also be referred to by the more technically accurate term "rotary position adjustment device".

[0014] According to the invention, the device has a first detection device arranged along the transport path of the plastic preforms (and in particular along a straight section of the transport path) for detecting a rotational position of the holding devices and / or the plastic preforms with respect to their longitudinal direction, wherein the plastic preforms and in particular the plastic preforms to be formed by the forming device and / or the plastic preforms heated by the heating device have at least one marking which enables detection of the rotational position of the plastic preforms.

[0015] It is possible that this marking is already present on the manufactured plastic preforms, but it would also be conceivable and preferred that this marking be applied to the plastic preforms before the heating device, however it would also be possible that the marking is applied during heating, or even after the plastic preforms have been heated.

[0016] Preferably, the detection device is suitable and designed to detect a marking on the plastic preforms in order to determine the rotational position of the plastic preforms.

[0017] In a further embodiment according to the invention, this positioning device extends at least section by section along the transport path of the plastic preforms (and in particular along a straight section of the transport path) and the device preferably has a first detection device arranged along the transport path of the plastic preforms for detecting a rotational position of the plastic preforms with respect to their longitudinal direction.

[0018] It should be noted that both embodiments (even independently of each other) can solve the aforementioned problems according to the invention.

[0019] Preferably, the transport device of the heating device comprises a circulating transport element on which the holding devices are arranged. This transport element is particularly preferably a transport chain. Preferably, the transport device transports the plastic preforms at least section by section along a straight transport path. More preferably, the transport device transports the plastic preforms at least section by section along a curved transport path, and particularly along a circularly curved transport path.

[0020] Preferably, the plastic preforms are heated during their straight-line transport.

[0021] In a further advantageous embodiment, an additional transport device is provided between the heating device and the forming device, which transports the plastic preforms. This additional transport device can, for example, be a transport wheel or a transport star, preferably also equipped with holding devices for the plastic preforms. In a further advantageous embodiment, the heating device is an oven, and in particular an infrared oven, which heats the plastic preforms. Preferably, the heating devices are arranged in a stationary position, and the plastic preforms are transported past them. Preferably, a plurality of heating devices are arranged in a stationary position along the transport path of the plastic preforms. These heating devices are preferably arranged along straight sections of the transport path.However, the heating device could also be a microwave oven.

[0022] In a further preferred embodiment, the heating power of the individual heating devices is controllable and, in particular, adjustable. Preferably, the heating power of the individual heating devices is controllable independently of one another and, more preferably, adjustable. Preferably, at least one heating device, and preferably several heating devices, each comprise heating lamps (arranged one above the other in the longitudinal direction of the plastic preforms) which extend along the transport direction of the plastic preforms. Preferably, the heating power of these heating lamps is adjustable.

[0023] Preferably, the positioning device ensures that all plastic preforms leave the heating device in a defined rotational position. In a further advantageous embodiment, the detection device includes an image acquisition device.

[0024] In a particularly preferred embodiment, the holding devices each have holding elements in the form of mandrels which engage in the openings of the plastic preforms to hold them. In a preferred embodiment, the device has movement devices which insert the holding mandrels into the plastic preforms. In a preferred embodiment, these holding elements are not only rotatable with respect to a predetermined axis of rotation and / or the longitudinal direction of the plastic preforms, but preferably also movable in the longitudinal direction of the plastic preforms.

[0025] In a preferred embodiment, the device has at least one drive unit which causes the individual plastic preforms, held by different holding devices, to rotate in the same way with respect to their longitudinal direction. It is conceivable that the rotational movement of the plastic preforms is effected by the movement of the plastic preforms along the transport path, for example, by means of gears arranged on the holding devices which interact with stationary racks.

[0026] Preferably, the forming device is suitable and intended for producing plastic containers with a cross-section other than a circular one. This could be, for example, a polygonal cross-section, an elliptical cross-section, an oval cross-section, and the like.

[0027] Preferably, the forming device has a movable and, in particular, rotatable support on which a plurality of forming stations for forming the plastic preforms into the plastic containers are arranged. Preferably, these forming stations each have a supply device that supplies the plastic preforms with a gaseous medium. Preferably, the forming stations each have rod-like bodies that can be inserted into the plastic preforms to stretch them in their longitudinal direction.

[0028] Preferably, the device has an allocation device which assigns to each plastic preform heated by the heating device a specific forming station which forms this plastic preform into a plastic container.

[0029] In a further embodiment, the device has at least one marking device suitable and intended for applying a mark to the plastic preforms, enabling the detection of a rotational position of the plastic preforms. Preferably, the marking device is a laser-based marking device or a printing device. Preferably, the marking is a permanent mark that preferably remains on the container manufactured from the plastic preform for the entire service life of the container. Preferably, the marking is optically and non-contact detectable.

[0030] Preferably, the marking device is positioned along the transport path of the plastic preforms through the heating device. Particularly preferably, the marking device is arranged closer to one end of the transport path along which the plastic preforms are heated than to the beginning. This allows the plastic preforms to be transported in a straight line initially, then the transport direction to be reversed in a deflection area, and finally the plastic preforms to be transported back. The marking device is particularly preferably arranged in this second transport path section, where the plastic preforms are transported back.

[0031] The marking device is particularly preferably suited and designed to apply said marking in a threaded area and / or on a support ring of the plastic preforms. This marking can particularly preferably be (at least) a line. In a further preferred embodiment, the marking device applies the marking to an area of ​​the plastic preform that will be covered by a container closure, and in particular a screw cap, during the subsequent manufacturing process of the plastic container. The marking device is particularly preferably applied to a section of the plastic preform that is not stretched and / or expanded during the forming process.

[0032] Thus, it is possible to apply the marking device orthogonally to a transport direction, such as a chain feed direction, within a specific section of the heating process curve, and particularly the preferential heating section. With appropriate adjustment of the marking system, the marking can always be applied centrally to a heated side of the plastic preform. As mentioned, the marking device is either a laser or a printing device.

[0033] Preferably, during the subsequent forming process, particularly a blow molding process, the position of this marking relative to a mold parting line is measured using a camera and image processing. The device may have a scale or a target marking on the mold or forming station to enable measurement relative to it.

[0034] In a further advantageous embodiment, the marking device is arranged along the transport path along which the plastic preforms are transported during heating. Particularly preferably, the marking device is arranged between an inlet and an outlet of the heating device. This allows the heating device to have a plurality of heating elements, such as heating boxes, which are stationary on the heating device. Marking can be carried out, for example, after the last of these heating boxes or after the last of these heating elements, but especially in a region where the holding elements, such as their spindles, are still guided by a process curve of the heating device. Alternatively, marking during the heating process would also be possible.

[0035] In a further advantageous embodiment, the device includes an alignment device that aligns the rotational position of the plastic preforms with respect to their longitudinal direction. This alignment device is preferably arranged along the transport path of the plastic preforms before or after the heating device, and more preferably before the positioning device. This means that the plastic preforms can be aligned even before heating. In this way, for example, a desired thread position of the plastic preform can be adjusted. This is particularly important when non-circular closures are to be screwed onto the non-circular containers, which consequently must be screwed onto the containers in the correct orientation.

[0036] In a further advantageous embodiment, the device has a second detection device for detecting the rotational position of the plastic preforms with respect to their longitudinal direction. This means that the rotational position of the plastic preforms is preferably detected at least twice along their transport path. This is particularly useful when preforms with a marking are used, for example, plastic preforms that already have a marking before the heating process. Preferably, the first of these detection devices is arranged in the heating unit, and the second detection device is particularly preferably located in the area of ​​the forming unit.

[0037] In a further preferred embodiment, the device has an assignment device which assigns a detection of a specific plastic preform by means of the first detection device to a detection of this plastic preform by means of the second detection device.

[0038] This makes it possible for the first detection device to detect a rotational position of the plastic preform and for the second detection device to also assign a rotational position to this plastic preform (or a plastic container produced from it) and for these rotational positions to be compared with each other.

[0039] Such an assignment is possible because the plastic preforms are preferably always transported individually, and therefore the number of plastic preforms between the two detection devices is known. Further parameters, such as the transport speed of the plastic preforms, can also be considered for assigning the detection results.

[0040] In a further preferred embodiment, the device has a comparison device which compares a detection result (for example, a recorded image or an evaluation thereof) of the first detection device with a detection result of the second detection device (but of the same plastic preform) and which preferably outputs a value characteristic of this comparison.

[0041] If plastic preforms with a marking for "neck orientation" are used, an additional marking is not necessarily required; instead, the plastic preforms can be inserted into the holding devices of the heating device in the correct position or placed on corresponding mandrels.

[0042] After the forming process, the position of the mark relative to the container orientation can then be measured. If, for example, a first position is used for a detection system, a scale or target mark on the mold or forming station can be used for relative measurement.

[0043] This design eliminates the need for additional marking of the plastic preforms. Furthermore, it allows for inspection of the containers instead of the more complex process of determining the position of the plastic preforms within the blow mold. Additional alignment of the rotation positions is also possible. However, this method requires that the plastic preforms be correctly positioned on the grippers of the heating unit.

[0044] If plastic preforms with a marking for neck ring orientation continue to be used, the position of this marking can be measured during the heating process with a first detection system and during the blowing process (from a first position) or after the forming process (from a second position) with the second detection system, and in this way a transfer angle can be calculated particularly preferably.

[0045] In a further preferred embodiment, the device includes a filling unit which is arranged downstream of the forming unit in the transport direction of the plastic containers and which is suitable and intended for filling the containers with a free-flowing product. This product can be, for example, a food product, but also other products such as oils, cleaning agents, or the like.

[0046] In a further preferred embodiment, the device has a closing device which is suitable and intended for closing the filled containers. Preferably, the closing device is suitable and intended for attaching screw caps to the containers.

[0047] When using the second detection system at a first position, a scale or target marking on the mold or forming station can again be used to measure relative to it, as mentioned above.

[0048] It would also be conceivable to use plastic preforms with a circumferential marking, for example, a barcode on the circumference of the plastic preform between the support ring and the locking ring, or on the top or bottom of the support ring. In this case, the position of the marking can be measured during the heating process using a first detection device and during or after the forming process using a second detection device, thus allowing the transfer angle to be calculated.

[0049] In a further advantageous embodiment, the device has a rotation position correction device which is suitable and intended to change a rotation position of containers in a defined manner, in particular to adapt an actual rotation position (especially one detected by a detection device) to a target rotation position.

[0050] It is possible that this marking is applied to the plastic preform during its production, for example during injection molding.

[0051] In addition, it is also possible that no extra marking is placed on the plastic preform, but rather that a significant feature of the plastic preform, for example a thread or thread spacing (for example the distance of the first lower thread flank to a locking ring), is detected and the position of this marking is measured during the heating process and after the forming process, and in this way a transfer angle is measured or calculated.

[0052] In a further preferred embodiment, at least one detection device comprises an image acquisition device capable of capturing an image of the plastic preforms in a direction perpendicular to their longitudinal direction. Preferably, this detection device is capable of capturing multiple lateral images of the plastic preform. It would be possible to provide multiple image acquisition devices that enable image capture of the plastic preform from multiple directions. It would also be conceivable to use mirrors to enable image capture of the plastic preform from multiple directions. In a further preferred embodiment, at least one detection device comprises an image acquisition device capable of capturing an image of the plastic preforms in their longitudinal direction.This detection device is particularly suitable and intended for capturing an image of a support ring and / or a thread of the container.

[0053] This approach can also be implemented using a machine learning system and / or artificial intelligence. For example, a large number of images of a rotating plastic preform can be taken under different lighting conditions, and these images can then be analyzed accordingly.

[0054] Should the required accuracy not be achievable, for example due to a speed gradient that is too shallow, it would also be possible to perform optimization by additionally evaluating vertical interruptions in the thread.

[0055] The adjusting device is a mechanically acting adjusting device and preferably the adjusting device has a guide roller arranged on the holding device which interacts with at least one first guide cam to set a rotational position of the plastic preforms.

[0056] In a preferred embodiment, the holding device comprises a plate on which this guide roller is arranged, wherein this guide roller is preferably arranged eccentrically, so that pivoting the guide roller also results in a rotational movement of the holding device and, in particular, of the plastic preforms held therein. Preferably, the holding device (or components thereof) is rotatable about an axis of rotation that runs parallel to the longitudinal direction of the plastic preforms. Particularly preferably, the guide roller is also rotatable about an axis of rotation that is parallel to the longitudinal direction of the plastic preforms.

[0057] Preferably, the positioning device has at least two and preferably at least three guide curves arranged one after the other along the transport path of the plastic preforms. The first guide curve can be a catch curve that predetermines the position of the guide roller. In a further embodiment, the second guide curve is a guide curve that aligns the guide roller.

[0058] In a further preferred embodiment, at least one, and more preferably several, of these guide curves are arranged in a straight section of the transport path. Preferably, at least one, and more preferably several, of these guide curves run in a straight line.

[0059] A guide cam is adjustable to change the rotational position of the plastic preforms. Adjustment of this guide cam is possible depending on the rotational position of the plastic preform, and in particular, on a rotational position that is or has been determined by the at least one detection device. This guide cam is particularly preferably adjustable perpendicular to the transport path of the plastic preforms, and especially in a horizontal plane. The guide cam is particularly preferably linearly displaceable, and in this way, the angular position of the guide roller can be changed.

[0060] In a particularly preferred embodiment, the aforementioned detection device is arranged along the positioning device. This means that the rotational position of the plastic preforms is detected while they are being aligned with the aforementioned guide cams.

[0061] In a further advantageous embodiment, the detection device is suitable and designed to detect the position of the guide roller relative to a longitudinal direction of the holding devices and / or relative to a longitudinal direction of the plastic preform.

[0062] It is possible that the guide roller or pivot roller (for example, the switching point of a sensor) is aligned with a coarse or fine clock signal to determine whether a spindle (or a holding device) is aligned before or after all (considered in the transport direction of the plastic preforms).

[0063] This is a preferred solution. Alternatively, the time interval between detected guide rollers or pivot rollers could be considered, as it can be assumed that most spindles are correctly oriented. In this way, a time interval that is too short compared to the target interval between two detected guide rollers could indicate that the last detected guide roller was incorrectly aligned ahead of schedule. Conversely, a time interval that is too long compared to the target interval between two detections could indicate that the last detected guide roller and / or spindle is now correctly aligned again.

[0064] In a further advantageous embodiment, the device includes a processor unit which is suitable and designed to determine, from values ​​output by the detection device, a characteristic state of an actuator. For example, it can be determined that a cluster of error states is occurring. In this way, it is possible to infer, for instance, wear of the guide roller or the guide cams.

[0065] In a further advantageous embodiment, the detection device is suitable and designed to detect a fault condition of the actuating device without contact.

[0066] In a further advantageous embodiment, the positioning device comprises a first positioning element which is suitable and intended to move and / or pivot the guide roller into a first predetermined position with respect to the longitudinal direction. This first positioning element may be comb-shaped and serve to pre-orient the guide rollers or pivot rollers at a predetermined angle.

[0067] In a further advantageous embodiment, the adjusting device has a second adjusting means, which is preferably arranged in the transport direction of the plastic preforms after the first adjusting means and which is suitable and intended to move or pivot the guide roller into a first predetermined position with respect to the longitudinal direction.

[0068] In a preferred embodiment, the marking of the plastic preforms is arranged in the area of ​​an opening and / or in a base area of ​​the plastic preform, in particular a base dome area. Preferably, the opening can be arranged in an area of ​​the plastic preform that is not stretched during the forming process or in an area that is not stretched during the forming process (in particular the thread area and / or the opening area).

[0069] Preferably, the marking is placed in an area along the transport path where no rotation of the plastic preform occurs with respect to its longitudinal direction. Preferably, the marking is placed in an area along the transport path where rotation of the plastic preform with respect to its longitudinal direction is prevented, particularly in an area of ​​the aforementioned curves and / or the positioning device.

[0070] The marking can be applied, for example, using a laser, a stamping tool, or a print.

[0071] Placing the marking in a raised area of ​​the ground has the advantage of facilitating axial inspection, which is generally more accurate than radial inspection. An inspection unit for performing this inspection is known from DE 10 2006 047150A1.

[0072] It is possible to first perform a test run with a plastic preform bearing a manually applied mark, and only then to blow through a container. This approach eliminates the need to inspect the plastic preforms in the heating unit, as their fixed or unambiguous (rotational) position is already established.

[0073] It should be noted that the position of the plastic preforms in a transport system, for example in a star-shaped conveyor, is subject to considerable play. This can lead to potentially inaccurate or uneven marking. Inaccurate measurements can also occur, for example, with markings in the crest area due to off-center measurements.

[0074] When marking the dome of plastic preforms, it is preferable to first check whether this area is even suitable for detection due to the injection point. Furthermore, it is conceivable that markings in the dome area could cause problems during the stretching of the material.

[0075] Furthermore, markings outside the mouthpiece (e.g. in the tip) are not visible from the outside during the blowing process, so it is preferable to inspect these markings outside the forming process.

[0076] The present invention further relates to a method according to claim 9 for manufacturing plastic containers, wherein plastic preforms are heated with a heating device, wherein the heating device comprises a transport device which transports the plastic preforms singly along a predetermined transport path, and wherein this transport device comprises a plurality of holding devices which hold the plastic preforms, and at least one heating unit which heats the plastic preforms, and wherein furthermore a rotating device rotates the plastic preforms held by the holding devices with respect to their longitudinal directions during their transport through the heating device, and wherein furthermore a forming device forms the plastic preforms transported by the heating device into plastic containers.wherein this heating device has at least one forming station which forms the plastic preforms into the plastic containers by applying a flowable (and in particular gaseous) medium.

[0077] Furthermore, the heating device has an actuating device which changes the rotational position of the plastic preforms (especially during their transport along their transport path) and a first detection device arranged along the transport path of the plastic preforms detects the rotational position of the plastic preforms with respect to their longitudinal direction.

[0078] In a first method according to the invention, the plastic preforms heated by the heating device have at least one marking which enables the rotational position of the plastic preforms to be detected.

[0079] In a second method according to the invention, a second detection device arranged along the transport path detects a rotational position of the plastic preforms.

[0080] It should be noted that the two methods described here can be used independently of each other or together.

[0081] In an advantageous method, a marking device applies a marking to the plastic preforms which enables the detection of the rotational position of the plastic preforms with respect to their longitudinal direction, wherein the marking is preferably applied during the heating of the plastic preforms.

[0082] In a further advantageous embodiment, the rotational position of the plastic preforms is changed by means of a mechanical adjusting device and, in particular, by means of at least one and preferably several guide cams. Preferably, this guide cam is adjusted depending on the rotational position of the plastic preform. Particularly preferably, the rotational position of the plastic preform is determined by the at least one detection device.

[0083] In another preferred method, the marking is applied in an area of ​​the positioning device, i.e., in particular while the plastic preforms are being transported through the positioning device.

[0084] Preferably, in the area of ​​the preferential heating process curve, i.e. preferably while the preferential heating spindles are guided in the curve and thus their orientation is known, a marking is applied, in particular in the dome area of ​​the plastic preforms, especially with a laser or printing process or mechanically, e.g. by a stamp.

[0085] In another preferred method, a detection device detects the position of the marking, preferably detecting the position of the marking immediately before or after the forming process.

[0086] After the blow molding process, the position of this marking relative to the impression of the mold parting line and / or relative to the bottle shape and / or relative to other prominent areas is measured using a camera (preferably in axial alignment to the plastic preform) and image processing.

[0087] The transfer angle can be calculated from the position of the mark relative to the spindle and the measured value.

[0088] If the marking is applied to the domed area of ​​the plastic preform, it should be noted that the subsequent blow molding process can make the marking difficult to detect. For example, the shape of the marking may be so distorted that it is no longer detectable, or the position of the marking in the stretched area may be altered due to the blow molding process.

[0089] In another preferred method, the position of this marking relative to the mold or mold parting line or target marking on the mold is measured - preferably immediately - before or during the blowing process by means of a camera (preferably in axial orientation to the plastic preform) and image processing.

[0090] In this case, the measurement accuracy is not affected by the blowing process, as the measurement can be taken beforehand.

[0091] In another preferred method, the marking is applied to the plastic preforms before they are heated.

[0092] It is particularly preferred that the marking is applied before the plastic preforms are fed into the heating device and / or before holding devices of the heating device, such as in particular its holding mandrels, grip the plastic preforms and / or enter their openings.

[0093] Preferably, the plastic preforms are marked while being fed to the heating unit by means of a feeding device. This feeding device could, for example, be a sawtooth star that transports the plastic preforms.

[0094] A marking can be applied before the plastic preforms are placed onto the furnace grippers or holding mandrels. For example, while the plastic preforms are in the pockets of the sawtooth star, a marking is applied to the unstretched area (e.g., on the top of the support ring) of the plastic preform using a laser or printing process, or mechanically, e.g., with a punch, preferably with zero play. Furthermore, the furnace spindles or holding mandrels are preferably oriented before placement, so the position of the marking relative to the spindle is known. (A deviation of less than 1° can be achieved here.)

[0095] It is conceivable that the markings are applied so accurately and the plastic preforms are then placed onto the retaining mandrels with such high precision (or the retaining mandrels are inserted into the openings of the plastic preforms) that an angular error of less than 1° results.

[0096] In another preferred method, the marking is applied and / or the component is attached with relatively low accuracy, such as an angular error of less than 30°, and the angular position is subsequently measured, in particular the position of the marking relative to a spindle position is determined, especially to achieve an error of less than 1°.

[0097] In this case, too, it is possible to measure the position of the mark relative to the blow mold, whereby a reference mark on the blow mold can also be used for this purpose.

[0098] In addition, it would be possible to measure the position of the mark relative to the bottle shape after the blow molding machine.

[0099] From these two values, i.e., the relative position of the mark with respect to the spindle and the relative position of the mark with respect to the blow mold or the container, the transfer angle can be calculated.

[0100] Further advantages and embodiments can be seen from the attached drawings.

[0101] It shows: Fig. 1 a schematic representation of a device according to the invention; Fig. 2 a representation of a holding device for holding the plastic preforms; Fig. 3 a top view of the holding device made of Figure 2 Fig. 4 a detailed view of the heating device; Fig. 5 a view of the adjusting device for changing the rotational position of the plastic preforms; Fig. 6 a view of changing the rotational position of the plastic preforms; Fig. 7 a further view of a holding device for holding the plastic preforms; Fig. 8 a top view of the holding device made of Figure 7Fig. 9 a schematic representation of a device according to the invention; Fig. 10 another schematic representation of a device according to the invention; Fig. 11 another schematic representation of a device according to the invention; Fig. 12 another schematic representation of a device according to the invention; Fig. 13 another schematic representation of a device according to the invention; Fig. 14 a representation of a detection device; Fig. 15 a representation of an actuating device; Fig. 16 a representation of an actuating device; Fig. 17 another representation of an actuating device; Fig. 18 a representation illustrating the detection of a rotational position; Fig. 19 a representation of a heating device; Fig. 20a,b two representations for attaching a mark to the floor; Fig. 21 a representation illustrating the detection of a rotational position; Fig. 22 a representation illustrating the detection of a rotational position; Fig.Fig. 23 is a representation illustrating the detection of a rotational position; and Fig. 24 is a representation illustrating the detection of a rotational position.

[0102] Figure 1 Figure 1 shows a schematic representation of a device 1 for manufacturing containers. Reference numeral 2 refers to a heating device, such as an oven, which heats plastic preforms 10. Preferably, this is an infrared heating device. This heating device includes a transport device 22, shown only schematically, which is designed here as a circulating chain on which a plurality of holding devices (not shown) for holding the plastic preforms 10 are arranged.

[0103] Reference numeral 24 designates a heating unit, such as a heating box, which is arranged in a stationary position relative to the transport device 22, and past which the plastic preforms are transported. In a preferred embodiment, heating devices are also provided on the inside of the transport path.

[0104] In a preferred embodiment, the heating device also includes cooling devices suitable for cooling a surface of the plastic preforms, for example by supplying them with air. In this way, uniform heating of the plastic preforms along their wall can be achieved.

[0105] As mentioned at the beginning, the plastic preforms are to be heated at preferred areas 10a, here at the points in Figure 1shown areas. For this purpose, the plastic preforms are aligned in their rotation so that some sections 10a are heated more than others.

[0106] The heated plastic preforms are transferred by means of a transport device 14, such as a star conveyor, to the forming device designated 4 in its entirety. This forming device has a plurality of forming stations 40, which are arranged on a transport device 42 like a blow mold. The plastic preforms are fed into these forming stations or blow molds and formed into containers.

[0107] Several transport devices, such as transport stars, for example at least two and preferably at least three transport devices, can also be arranged between the heating device.

[0108] In the area marked K, the rotational position of the plastic preforms can be corrected. In the forming device 4, the more heated surfaces of the plastic preforms are aligned with the longer sides of the blow molds. Preferably, the plastic preforms are aligned such that a parting line or parting plane is located on the narrow side of the container. Reference numeral 28 schematically denotes a rotary device for rotating the plastic preforms 10 with respect to their longitudinal directions.

[0109] Figure 2Figure 1 shows a representation of a holding device 26. This device has a support 29, which can be arranged on a circulating transport means such as a conveyor chain. Reference numeral 32 denotes a rotatable plate on which a cam roller 34 is arranged. This plate is rotatable with respect to the longitudinal direction L. This longitudinal direction also corresponds to the longitudinal direction of the (not shown) plastic preform.

[0110] Reference numeral 36 denotes a gear or toothed ring that can roll relative to or engage with a stationary rack (not shown). Reference numeral 37 denotes an alignment surface used to pre-align the rotational position of the plastic preform. In this way, a defined rotational position of the plastic preform can be achieved.

[0111] Figure 3 shows a top view of the in Figure 2The holding device shown. Here again, the cam roller 34 is provided, which is arranged on the rotatable plate 32. The gear 36 is also visible.

[0112] Reference numeral P1 denotes a travel path of a corresponding guide curve when an angular correction, for example by 90°, is to be made. Reference numeral S1 denotes a curve position during directed heating or preferential heating of specific areas of the plastic preform.

[0113] Figure 4 shows a detailed representation of the in Figure 1 The device shown. Reference numeral 30 denotes an adjusting device which serves to align the plastic preforms or to adjust their rotational position. Preferably, this adjusting device is arranged in the second half of the transport path along which the plastic preforms are transported during their heating.

[0114] Figure 5Figure 1 shows a detailed representation of this positioning device. It features sequentially arranged curve segments 35a, 35b, and 35c along the transport path T. Reference numeral 35a designates a capture curve, which is suitable and intended to capture the cam roller 34 or to engage it in any desired position. Within this capture curve, the cam roller 34 is pre-aligned. A process curve 35b follows this capture curve 35a, within which the plastic preforms are preferably heated in the given position.

[0115] The process curve 35b is followed by a transfer curve 35c, which aligns the rotational position of the plastic preforms in a desired shape in order to transfer the plastic preforms to a further transport device. 14to be transferred. In a preferred embodiment, the positions of the process curve and / or the transfer curve are variable in order to adapt the rotational position to different process conditions.

[0116] In another preferred embodiment, the device includes a drive unit for adjusting the process curve and / or the transfer curve. For example, an electromechanical drive unit can be provided which effects an adjustment of the process curve and / or the transfer curve.

[0117] Figure 6 The transfer curve illustrates how a spindle rotation in a clockwise direction (top view) is initiated. This results in the outer side of the plastic preform being oriented in the blow mold opposite to the rotational direction of the blow wheel.

[0118] Figure 7Figure 1 shows another illustration of the holding device. Here again, the guide roller 34 is shown on the rotatable plate 32. Reference numeral 26A designates a mandrel that engages in the openings of the plastic preforms to hold them in place. This mandrel 26A may also have clamping mechanisms for clamping the plastic preform.

[0119] Figure 8 shows a top view of the in Figure 7 The holding device shown. Here again, the guide roller 34 is arranged on an arm 35, which in turn is attached to the plate 32. The guide cams allow a 90° correction of the rotational position of the spindle drive or the guide roller.

[0120] Due to the preferably adjustable or movable process curve 35b (see Figure 5All the concepts described below can also be used to control or adjust the average transfer angle. For this purpose, the drive of the process curve is preferably readjusted depending on a measured transfer angle.

[0121] In this way, for example, process control of preferential heating machines can be carried out (for example, to counteract a drift of the transfer angle during the warm-up of the furnace).

[0122] In addition, new customer objects can also be used on appropriate machines that allow preferential heating.

[0123] Figure 9Figure 1 shows a first representation of a device according to the invention. In this embodiment, a marking device 12 is provided which applies a marking to the plastic preform. As mentioned above, this marking is preferably applied to the hot side of the plastic preform, i.e., the area that is preferably heated more.

[0124] Reference numeral 18 designates a detection device that detects the position of this marking. This detection device is preferably assigned to the forming unit 4. The positioning of the detection device 18 allows for good integration of the detection system into the forming unit. Furthermore, this detection device 18 does not obstruct access to the forming unit via the two doors 45 of the forming unit. Therefore, the accessibility of the forming unit is not hindered by the detection device 18.

[0125] At the in Figure 9 In the embodiment shown, the marking device can have 2 sub-devices 12 which are arranged on opposite sides of the plastic preform or its transport path.

[0126] Figure 10 Figure 1 shows a further embodiment of a device according to the invention. In this embodiment, alignment devices 15 can be provided which, for example, already align the rotational position of the plastic preforms before they enter the heating device.

[0127] In addition, alignment can also take place in the first part of the heating device, where the plastic preforms are transported from left to right (and where they are preferably also heated uniformly in the circumferential direction). An alignment device 15 is also conceivable in the deflection area. Thus, an alignment device can be provided at the three positions shown. This alignment device 15, as mentioned, causes a change or alignment of the rotational position of the plastic preform. Preferably, this alignment device 15 is arranged in the transport direction of the plastic preforms upstream of the adjusting device 30.

[0128] In addition, possible detection devices or detection systems 18 are again provided at or after the transformer.

[0129] Figure 11Figure 1 shows a further embodiment of the device according to the invention. In this embodiment, plastic preforms with a marking for neck orientation are also used. This marking can be applied during the heating process using the marking device and preferably detected by a first detection system or a sensing device (not shown), and detected again during the blow molding process by a second detection system or a second sensing device 18. In this way, the transfer angle can be calculated.

[0130] Figure 12Figure 1 shows another representation of a device according to the invention. In this embodiment, plastic preforms with a circumferential marking are provided, for example, with a barcode on the circumference of the plastic preform. Here, too, the rotational position of the plastic preform can be detected independently of the setting. However, here as well, plastic preforms must be provided that already have a marking. Depending on the detected markings, the aforementioned adjusting device can effect a correspondingly adapted rotational position of the plastic preforms.

[0131] Figure 13 shows a further embodiment of a device according to the invention. This largely corresponds to the one in Figure 11The device shown is similar. However, this method does not use a plastic preform with an extra marking; instead, the rotational position is determined based on characteristic features of the plastic preform, such as the position of a thread. For example, an image of the transported plastic preform can be taken, and the rotational position can be determined from this image using characteristic features such as the start of a thread.

[0132] Figure 14 Figure 1 shows a further representation of a part of an actuating device 30 according to the invention, namely the catch cam 35a. A first actuating element 52 is provided, which is designed, for example, in the form of a comb 52 that engages from above into the aforementioned guide roller of the holding device. Reference numeral 34 again designates the guide roller by means of which the rotational alignment is effected.

[0133] Figure 15 Figure 3 shows a more detailed representation of the adjusting device 30. The first comb 52 is again shown. A stop 56 is attached to this comb, which orients the guide rollers or pivot rollers at a 45° angle to the outside of the furnace relative to the spindle center.

[0134] Since, after this pre-orientation, the guide rollers or control rollers could still be aligned 45° ahead or behind the spindle center, a second pushing device or a second actuating element 54, such as a second comb, which preferably engages laterally from the outside of the heating device onto the guide rollers or control rollers, ensures that the leading guide rollers are also oriented in the desired position, i.e., 45° behind the spindle center on the outside of the oven.

[0135] Figure 16Figure 1 shows a detailed representation of the first pushing element or the first comb. This element has a plurality of blades 52a, each separated from the others by grooves or slots 52b, so that they are independently movable. The material of these blades can be, for example, an elastic material and / or a plastic material.

[0136] Figure 17 shows a representation of the stop 56, which serves to orient the guide rollers or pivot rollers relative to the spindle center.

[0137] Figure 18Figure 1 shows a diagram illustrating the invention. A total of four holding devices or spindle rollers are provided. It can be seen that in the second holding device, marked with a cross, the guide roller 34 leads in the transport direction T, while the other guide rollers lag behind. This can be detected, for example, with a detection device such as an image analysis system. Preferably, this misorientation can be assigned to the corresponding holding device, which can then be corrected if necessary. It would also be possible to output an error signal to the user or machine operator.

[0138] Figure 19Figure 1 shows a representation of a heating device. The black rectangles indicate where (I, II, III, IV) a detection device or evaluation device for recording the rotational position of the plastic preforms can be located.

[0139] As mentioned, the monitoring of the spindle alignment or the rotational position of the plastic preforms can take place at the end of the capture curve 35a (I) or in the area of ​​the process curve 35b (II) or in the area of ​​the transfer curve 35c (III) or anywhere between these curves or in the area of ​​a control head (IV).

[0140] Monitoring should take place after alignment and before the spindles on the chain feed side are rotated again. This monitoring can be carried out using at least one, and preferably a multitude, of sensor devices. For example, proximity sensors based on different operating principles or light barriers, etc., would be suitable. Such light barriers could be positioned either above or to the side of the guide rollers or pivot rollers.

[0141] The Fig. 20a and 20b This shows another possible method for applying a mark to a plastic preform. In this case, a mark M is applied to a dome on the bottom of the plastic preform. Preferably, the plastic preform is inspected in its axial direction.

[0142] At the in Fig. 20aIn the illustration shown, the plastic preform 10, held by its holding device or the holding mandrel 26a, is inspected axially from above, or an image is taken in the axial direction from above. In this way, the position of the cam roller 34 can also be recorded, and the angle α1 can be determined from this.

[0143] At the in Fig. 20b In the illustration shown, the plastic preform is photographed axially from below to determine the position of the mark M. From this, the angle α2 can be determined, and from the two angles α1 and α2, the rotational position of the plastic preform can be determined.

[0144] Fig. 21Figure 1 shows an advantageous embodiment of a device according to the invention. A marking device 12 is provided, which applies a marking to the plastic preform. This marking device is arranged in that area of ​​the transport pad where the plastic preform does not rotate with respect to its longitudinal direction or where its rotational position is determined by the guide curves, i.e., in particular in the area of ​​the adjusting device 30. The marking can be arranged, as mentioned above, on the bottom dome or in another area of ​​the plastic preform, for example, its (non-stretchable) mouth area.

[0145] Reference numeral 18 indicates a detection device, which is located here after the blow molding machine and which detects a position of the marking.

[0146] Fig. 22Figure 1 shows an advantageous embodiment of a device according to the invention. The arrangement of the marking device corresponds to that shown in Figure 2. Fig. 21 situation shown. In the Fig. 22 In the embodiment shown, however, each conversion station is assigned a detection device 18 which detects a position of the marking.

[0147] Fig. 23 Figure 1 shows a further advantageous embodiment of a device according to the invention. In this embodiment, a marking device is arranged upstream of the heating device, for example in the area of ​​a sawtooth star that feeds the plastic preforms to the heating device.

[0148] The inspection of the plastic preforms or containers is carried out using detection and / or evaluation devices located at and / or after the forming device. Cumulative evaluation at both positions is conceivable and advantageous. This type of evaluation can also preferably be performed independently of the marking position. It can be advantageous to position the marking on an area of ​​the plastic preforms that is not formed or stretched.

[0149] At the in Fig. 24 In the embodiment shown, a marking device 12 is provided upstream of the heating device and a first inspection device 18a is located in the area of ​​the actuating device 30. A second inspection device 18b can be arranged here alternatively or cumulatively at and / or downstream of the forming device.

Claims

1. Apparatus (1) for producing plastic containers (10) with a heating device (2) for heating plastic preforms (10), wherein the heating device (2) has a transport device (22) which transports the plastic preforms individually along a predetermined transport path (T), and this transport device (22) has a plurality of holding devices (26) for holding the plastic preforms and at least one heating unit (24) is provided which heats the plastic preforms (10), wherein further a rotating device (28) is also provided which rotates the plastic preforms (10) held by the holding devices (26) relative to their longitudinal direction during their transport through the heating device (2), and a forming device (4) which forms the plastic preforms (10) transported by the heating device (2) into plastic containers, wherein this forming device (4) has at least one forming station (40) which forms the plastic preforms (10) into plastic containers by applying a flowable medium, wherein the heating device has an adjusting device (30) which enables a rotational position of the plastic preforms (10) to be adjusted, and the apparatus has a first detection device (18) arranged along the transport path (T) of the plastic preforms for detecting a rotational position of the plastic preforms relative to their longitudinal direction, wherein the plastic preforms to be formed by the forming device have a marking which enables a detection of the rotational position of the plastic preforms, wherein the adjusting device is a mechanically acting adjusting device and the adjusting device has a guide roller arranged on the holding device, which interacts with at least one first guide curve in order to adjust a rotational position of the plastic preforms, and at least one guide curve is adjustable in order to change the rotational position of the plastic preform, wherein an adjustment of this guide curve can be carried out as a function of a rotational position of at least one plastic preform.

2. Apparatus according to claim 1, characterized in that the forming device (4) is suitable and designed to produce plastic containers with a cross-section that deviates from a circular shape.

3. Apparatus (1) according to at least one of the preceding claims, characterized in that the apparatus (1) has a marking device (12) which is suitable and intended to apply a marking (M) to the plastic preforms, which marking enables the rotational position of the plastic preforms to be detected, wherein the marking device is preferably a laser-based marking device or a printing device.

4. Apparatus (1) according to claim 3, characterized in that the marking device is arranged along the transport path along which the plastic preforms are transported during their heating.

5. Apparatus (1) according to at least one of the preceding claims, characterized in that the apparatus (1) has an alignment device which aligns the rotational position of the plastic preforms with respect to their longitudinal direction relative to the holding device 26, wherein this alignment device is preferably arranged along the transport path of the plastic preform before the heating device (2) and / or before the adjusting device (30).

6. Apparatus (1) according to at least one of the preceding claims, characterized in that the apparatus has at least one second detection device (18) for detecting the rotational position of the plastic preforms relative to their longitudinal direction.

7. Apparatus (1) according to the preceding claim, characterized in that the adjusting device has at least two and preferably at least three guide cams, which are arranged one behind the other along the transport path of the plastic preforms.

8. Apparatus (1) according to at least one of the preceding claims, characterized in that the marking of the plastic preforms is arranged in an area of an opening and / or in a bottom area of the plastic preform.

9. Method for producing plastic containers (10) wherein plastic preforms (10) are heated by a heating device (2), wherein the heating device (2) has a transport device (22) which transports the plastic preforms individually along a predetermined transport path (T), and this transport device (22) has a plurality of holding devices (26) which hold the plastic preforms, and at least one heating unit (24) is provided which heats the plastic preforms (10), and wherein, furthermore, a rotating device (28) rotates the plastic preforms (10) held by the holding devices (26) relative to their longitudinal direction during their transport through the heating device (2), and wherein a forming device (4) forms the plastic preforms (10) transported by the heating device (2) into plastic containers, wherein this forming device (4) has at least one forming station (40) which forms the plastic preforms (10) into plastic containers by applying a flowable medium, wherein the heating device has an adjusting device (30) which changes a rotational position of the plastic preforms and a first detection device (6) arranged along the transport path (T) of the plastic preforms detects the rotational position of the plastic preforms relative to their longitudinal direction, wherein the plastic preforms (10) to be formed by the forming device have at least one marking which enables the rotational position of the plastic preforms to be detected, wherein the adjusting device is a mechanically acting adjusting device and the adjusting device has a guide roller arranged on the holding device, which interacts with at least one first guide curve in order to adjust a rotational position of the plastic preforms, and at least one guide curve is adjustable in order to change the rotational position of the plastic preform, wherein an adjustment of this guide curve can be carried out as a function of a rotational position of at least one plastic preform.

10. Method according to claim 9, characterized in that a marking device applies a marking M to the plastic preforms (10), which enables the rotational position of the plastic preforms to be detected with respect to their longitudinal direction, wherein the marking is preferably applied during the heating of the plastic preforms.

11. Method according to at least one of the preceding claims, characterized in that the rotational position of the plastic preforms is adjusted by a mechanical adjusting device and, in particular, by at least one guide curve, wherein an adjustment of this guide curve preferably takes place as a function of a rotational position of the plastic preform.

12. Method according to at least one of the preceding claims, characterized in that the marking is applied in a region of the adjusting device (30) or in front of the heating device (2).

13. Method according to at least one of the preceding claims, characterized in that a detection device detects a position of the marking and preferably detects the position of the marking immediately before the forming process or after the forming process.