US20140331617A1

US20140331617A1 - Apparatus and method for the production of sets of containers

Info

Publication number: US20140331617A1
Application number: US14/258,565
Authority: US
Inventors: Christian Napravnik
Original assignee: Krones AG
Current assignee: Krones AG
Priority date: 2013-05-07
Filing date: 2014-04-22
Publication date: 2014-11-13
Also published as: EP2801533B2; CN104139894A; CN104139894B; DE102013104666A1; EP2801533A1; ES2619609T3; EP2801533B1

Abstract

An apparatus (1) for the production of sets of containers (10), wherein the apparatus has a packaging device (2) which wraps a plurality of containers (20) at least in part with a film-like packaging material (12) and thus forms a set of containers (10), with a shrinking device (4) which shrinks the packaging material (12) which wraps the containers (20) at least in part, with a conveying device (6) which conveys the containers (20)—wrapped by the packaging material (12)—in a pre-set conveying direction, and with an inspection device (8) which inspects the containers (20)—wrapped at least in part by the packaging material (12)—after the shrinking procedure.

Description

BACKGROUND

The present invention relates to an apparatus and a method for the production of sets of containers and, in particular, of shrink-wrapped packs. Such shrink-wrapped packs have long been known from the prior art. They usually have an assembly of a plurality of articles and, in particular, containers, which are held together by a packaging material. In this case it is known from the prior art for an assembly of a plurality of articles first to be formed and for the latter to be wrapped at least in part in a film-like packaging material, and in a further step for this packaging material to be shrunk onto the set of containers, for example by this material being shrunk by the action of heat.
It is usual for methods of this type also to operate in a highly satisfactory manner. In individual cases, however, it may happen that the sets of containers are assembled in an irregular manner, for example individual containers are offset with respect to others. Sets of this type can result in difficulties in the further processing, for example during the transportation or stacking. In addition, during the wrapping of the assembled containers with film it is also possible for an offset to occur, such as for example a diagonal impact or an offset of the film (the projection of the film to the left and right is not equal in size). The formation of creases, irregular film eyes at the sides or open packets may occur in the shrink tunnel as a result for example of changes in the properties of the film due to different batches or incorrect setting of the shrink tunnel. In addition, overlap creases and the formation of holes in the film are possible.
A goal of the present invention is therefore to make available an apparatus and a method which permit a smoother procedure in the production of shrink-wrapped packs of this type. This object is attained according to the invention by the subjects of the independent claims. Advantageous embodiments and further developments form the subject matter of the sub-claims.

SUMMARY OF THE INVENTION

An apparatus according to the invention for the production of sets of containers has a packaging device which provides a plurality of containers, at least in part, with a film-like packaging material and, in particular, wraps them at least in part and thus forms a set of containers.
Furthermore, the apparatus has a shrinking device which shrinks the packaging material which wraps the containers at least in part. In addition, the apparatus has a conveying device which conveys the containers—wrapped at least in part by the packaging material—in a pre-set conveying direction. Finally, an inspection device is also provided which inspects the containers—wrapped at least in part by the packaging material—after the shrinking procedure.
The expression “wrap at least in part” is understood that the packaging material need not (but can) surround the set of containers over the entire periphery thereof, but that recesses and apertures (also referred to as “eye” below) for example can also be formed. It is preferable for the packaging material to surround the set of containers completely at least in a peripheral direction. It is advantageous for the packaging material to be formed in such a way that at least one lateral face of the set of containers is covered completely by the packaging material. It is advantageous for at least two and preferably at least three and preferably at least four lateral faces of the sets of containers to be covered completely by the packaging material or to be closed by the latter respectively.
In the case of a further advantageous embodiment the film-like material is a plastics material. In the case of a further advantageous embodiment the apparatus also has a group-forming device which forms pre-set groups of containers, these groups having pre-set numbers of containers. It is advantageous for this group-forming device to be arranged upstream of the packaging device in the conveying direction of the containers.
Furthermore, it is preferable for the shrinking device to have a heating device for heating the packaging material. In this case the shrinking device can be designed in the form of a shrink tunnel through which the sets of containers with the film applied to them are conveyed, in which case the heating of the film causes the latter to be shrunk onto the set of containers.
The conveying device can be for example a conveyor belt or a conveying chain.
In the case of a further advantageous embodiment the inspection device inspects the sets of containers without contact.
In the case of a further advantageous embodiment the packaging material is transparent at least in part. It is advantageous for the packaging material also to be flexible at least locally and preferably completely and for it to be capable of being adapted at least locally to a surface structure of the containers.
In the case of a further advantageous embodiment it is also possible for the conveying device to convey the packs in a plurality of paths, i.e. a plurality of sets of containers can also be conveyed adjacent to one another in a direction at a right angle to a conveying direction. In this case it is possible for the inspection device to observe a plurality of these sets of containers simultaneously. It would also be possible, however, for a plurality of inspection devices to be used in parallel.
In the case of a preferred design an automatic inspection is thus proposed. It is advantageous for the inspection device to allow an automatic measurement of the set of containers.
In this case it is possible for example for the exceeding of tolerances to be detected. In particular, it is possible in this case for external dimensions of the sets of containers and, in particular, also deviations from pre-set reference dimensions to be measured. In the same way, any desired geometrical arrangement of the containers in the pack can be pre-set as a nominal pattern.
Geometrical arrangement[s] of the containers as well as tolerance values and dimensions as well as configuration features are filed in the image-processing computer or the control device respectively in a manner specific to the type or batch respectively. The choice of the parameters required in each case can be made for example by way of the master computer of the plant as a whole or by way of the lead machine arranged upstream.
Besides this and/or in addition, it is also possible for the inspection device to inspect the position and/or dimensions or geometry respectively of the above-mentioned opening in the packaging material.
In the case of a further advantageous embodiment the apparatus has a control or regulating device which controls the packing device and/or the shrinking device in a manner dependent upon a result or measurement value respectively detected by the inspection device.
In the case of a further advantageous embodiment the apparatus has a separation device which is preferably arranged downstream of the inspection device and which allows specified sets of containers, in particular sets of containers detected as being defective in some way, to be separated out. In this case it is possible for a control device of this type to be able to differentiate between those sets of containers which can cause a breakdown—for example in the conveying of the packs or in the palletizer—in continuous operation, and those which are still acceptable for further processing.
In the case of a further advantageous embodiment the inspection device is arranged downstream of the shrinking device in the conveying device of the containers. It is advantageous for the inspection device also to be arranged in a region of the apparatus which is situated downstream of the shrinking device. In addition, however, a further inspection device could also be provided, which for example monitors the shrinking device itself, such as for example a camera which detects the inner workings of the shrinking device at least in part.
It is advantageous for the inspection device to be arranged directly downstream of the shrinking device, i.e. for example directly at an outlet of a shrink tunnel. The advantage of an arrangement of this type lies in short dead zones in the regulation. It is preferable for the inspection device to be arranged in such a way that in normal working operation and after leaving the shrinking device the sets of containers reach the inspection device within a period of time which is shorter than 10 s, preferably shorter than 6 s, preferably shorter than 5 s, and in a particularly preferred manner shorter than 3 s.
In the case of a further advantageous embodiment the inspection device has an image-recording device which is suitable and provided for recording images of the sets of containers. This image-recording device is preferably an image-recording device which can record spatially resolved images, such as for example a camera, a video camera, a CCD chip or the like. It is advantageous for the inspection device also to be suitable for recording an image of the entire set of containers, in particular also including the lateral faces thereof.
In this way, it is possible for example for an optical measurement to be carried out from a pre-set direction, and in particular from above. The expression “from above” is understood in this case to be a direction of observation which deals with the containers from above, i.e. in particular in an upright position, onto the closures thereof. In this way, it is possible for example for a camera, which is orientated in a pre-set manner and preferably vertically downwards, to be attached above a pack path.
In this case it is also possible for this image-recording device to be triggered, for example by a sensor, in order to cause in this way each set of containers to be observed in a pre-set position, for example precisely centrally. It is advantageous for the inspection device also to have an image analysis device which detects geometrical limits of the set of containers. In addition, this image analysis device can also be suitable for being able to determine the positions of the individual container ends or container closures respectively. Furthermore, the image analysis device can also be suitable for detecting the absence of individual containers in a set of containers.
In the case of a further advantageous embodiment the inspection device is therefore suitable for detecting a relative position of a container of the set of containers with respect to at least one further container of this set of containers and/or further magnitudes which can result from these relative positions. In this case it is advantageous for an evaluation unit also to be provided which evaluates these detected positions. In this way, for example, a comparator device can be provided, which compares the detected position with respect to a reference or a nominal position respectively.
In the case of a further advantageous embodiment the apparatus therefore has a position detection device which detects the position of the containers wrapped by the packaging material—in particular in the conveying direction but also advantageously transversely to the conveying device. It is advantageous for the image-recording device to record an image of the set of containers during the movement thereof, in particular during the movement thereof in the conveying direction. In this way, for example, a light barrier can be provided which triggers an image-recording device in a pre-set position of the set of containers.
The present invention further relates to an inspection device for the inspection of sets of containers, the sets of containers having a plurality of containers which are wrapped at least in part by a packaging material, in particular a packaging material in the manner of a film. This inspection device has an image-recording device which observes the sets of containers.
According to the invention the inspection device has an output device which emits at least one signal which is characteristic of a relative position of at least one container of the set of containers with respect to at least one second container of this set of containers and/or which is characteristic of at least one external surface of the set of containers and/or at least one pattern of this container surface with respect to an ideal pattern. In addition or as an alternative, however, this output device can also be designed in such a way that it emits a signal which is characteristic of the absence of one or more containers in the set of containers. It is advantageous for the inspection device to be suitable in this case for recording the sets of containers during a movement of the latter.
The output device can be for example an image output device, such as a monitor, which preferably provides the user in a suitable manner with information which allows conclusions to be drawn on the quality and value of a set of containers of this type.
In this case it is possible to indicate whether a value recorded by the output device exceeds specified tolerances. In this case it is also possible for a comparison with a reference image to be issued. In this way, a quality analysis of the set of containers is also generally possible. The quality of the sets of containers formed could thus be checked in a continuous manner, namely for example with respect to the dimensions of the sets of containers, with respect to the absence of individual containers, with respect to defects of the packaging material and the like.
In the case of a further advantageous embodiment the inspection device has a storage device in which references, for example reference images, are stored. It would also be possible, however, for these references to be simplified illustrations, for example rectangles, which are characteristic of the periphery of a set of containers of this type. In the case of a further advantageous embodiment this inspection device can be designed in a modular manner and, in particular, it can be arranged behind a shrinking device of a plant for the production of shrink-wrapped packs of this type. It would also be possible for images, which have been recorded by the sets of containers, to be stored in the aforesaid storage device, this storage being carried out in particular with an allocation to the respective set of containers recorded.
In the case of a further advantageous embodiment the image-recording device is arranged in such a way that it observes the set of containers from above. In this case for example a camera can be arranged vertically above a conveying path of the sets of containers, but it would also be possible for a direction of observation to be reversed, for example by way of mirror elements. As an alternative or, in particular, also in addition, it is also possible for observation of the sets of containers to take place from below.
In addition, however, it is also possible for observation to take place from different directions of observation, for example an observation from above, in order to ascertain an offset of the containers or the absence of containers, an observation from obliquely above, in particular in the conveying direction, in order to detect the end faces of the sets of containers, an observation from the side in order to detect the film eyes and/or an observation from below, for example in order to check the quality of the lower film overlap and the formation of holes in the base region.
In addition, the inspection device is suitable for observing, at least also in part, one and preferably a plurality of lateral faces of the set of containers and to record images also of these side regions. A lateral face is understood to be those areas of the set of containers which also extend in a direction of observation, i.e. for example in the case of a main direction of observation in the vertical direction those faces which also have an extension component in this vertical direction.
In the case of a further advantageous embodiment the apparatus has a position detection device which detects a position of the set of containers in the conveying direction thereof. Furthermore, it is preferable for a control device also to be provided which controls the inspection device in a manner dependent upon a detected position of the set of containers.
In addition, it is preferable for a regulating device to be provided which controls or regulates respectively at least one unit arranged upstream in the conveying direction of the sets of containers, i.e. in particular the packaging device and/or the shrinking device in a manner dependent upon an inspection result of the inspection device or the observation device respectively. In this case a regulation could be provided for example in the form of a closed regulating circuit.
Furthermore, it is possible, during or after the separation of packs, in particular mixed packs, for the machines arranged upstream to be controlled in such a way that the missing types are produced subsequently. Machines arranged upstream would in this case be the filling machine and the labelling machine as well as the sorting device or group formation device respectively, which have to produce the missing quantity subsequently in the correct pieces.
In the case of a further advantageous embodiment the inspection device has at least one lens member which is arranged between the set of containers or the conveying path thereof respectively and the image-recording device. This lens member can be for example, and also in a preferred manner, a Fresnel lens.
In the case of a further advantageous embodiment the inspection device has at least one beam deflection element which allows a lateral face of the set of containers to be observed. In this way for example, mirrors, prisms and the like can be provided which allow the aforesaid lateral faces to be observed.
In this way, it would be possible for example for one and preferably a plurality of sides of the set of containers also to be projected completely or in part in the direction of the image-recording device by way of a suitable mirror lens described in greater detail below. As an alternative and/or in addition, cameras could also likewise be provided laterally with respect to the conveying path of the set of containers, for example to the left or right of the set of containers. This would apply, in particular, in the case of a single-path operation of the apparatus.
In the case of a further advantageous embodiment it would also be possible for at least one beam deflection element or in general the observation lens or the mirror elements respectively to be attached in a movable manner (for example pivotable and/or rotatable) in order to be able to detect various regions of the pack of the set of packs while moving past. In addition, an improved observation of the entire set of containers can be achieved by a movability of this type.
In this way, the beam deflection elements could move for example at a speed adapted to the conveying speed of the set of containers, and it would also be possible for specific regions of the set of containers to be scanned by the movement of the beam deflection elements.
In the case of a multiple-path operation it would be possible for example for a first image-recording device to be arranged at the top with respect to the set of containers and for two further image-recording devices to be arranged in each case on the two outer sides of the multiple-path conveying device. In this case the deflection element or the aforesaid mirror lens respectively can be designed in such a way that the entire lateral face is imaged, but it would also be possible for only portions or parts respectively of the lateral faces to be observed in each case. In this way, it would be possible for the complete image of a lateral face to be put together again from a plurality of such sections.
Furthermore, the inspection device advantageously has a correction device which corrects errors caused by a lens, such as for example distortion.
As an alternative or in addition, so-called line scanners could also be used, in which a complete image is put together from individual columns of a side view.
In this case it is possible, as an alternative or in addition, for critical or problematic regions of these lateral faces, such as for example the welding of a lateral lower film tab, to be tested for their quality. For this purpose, a capacitive sensor for example can be used as a further inspection device.
It is possible for the quality of the sets of containers to be monitored and advantageously also to be logged in a continuous manner by way of a control means which can also be designed at least in part in the form of software. It is advantageous for the inspection device therefore to have a storage device which is suitable for storing detected measurement results of the inspection of the sets of containers. The subsequent regulation of a further unit, such as for example a packer and/or shrink tunnel arranged upstream or even an automatic separation out of sets of containers respectively, can likewise be achieved by way of the aforesaid control means.
In this case it is possible for the images recorded by the sets of containers to be stored, in particular in order to evaluate the quality of the sets of containers at pre-set time intervals.
In this way, it is possible for the evaluation also to be made independent of the user carrying out the evaluation in each case.
In addition, it is also possible for the sets of containers to be monitored with respect to colour properties, for example with respect to colour imprints on the packaging material. In this way, it would be possible for example for the position of colour patterns to be monitored, for example the position of a white logo on a ground of a different colour.
In this way, it is possible for example for the movement and the reception of the size of this logo to be monitored by the RGB value.
In the case of a further advantageous embodiment the inspection device is suitable for identifying specific points of a recorded image, for example the heads of the containers, and—with reference to this image—to issue a value which is characteristic of a geometrical arrangement of the individual containers within the set of containers.
As well as the inspection of the geometry of the set of containers, as described here, it is also possible, however, for other characteristics to be detected, such as for example the reading out of a barcode or another marking which is characteristic of the set of containers. In addition, it may also be advantageous for the packaging material to be checked for its quality, for example for distortion, holes and the like. In addition, the design of the set of containers can also be checked as a whole in this way.
In the case of a further advantageous embodiment it is also possible for a vertical profile of the set of containers to be measured. In addition, an evaluation with respect to further components of the set of containers can also be carried out. In this way, it is possible to check for example whether additional elements, for example a gripping arrangement (handle applicator), is present. In addition, OCRs and OCVs can also be evaluated. In addition, an inspection generally with respect to contamination, damage and also an identity of the set of containers can also be carried out.
In the case of a further advantageous embodiment the apparatus has at least one illumination device for illuminating the set of containers during the inspection. In this case it is possible for this illumination device to observe the set of containers from the same direction as is also observed by the image-recording device. It is therefore preferable for the illumination device also to be arranged above the packs with respect to the conveying path of the latter. It is preferable for a plurality of illumination elements or devices respectively to be provided which illuminate the set of containers preferably from a plurality of different directions. In this case, however, it is preferable for all the illumination devices to be arranged in a pre-set region with respect to a conveying plane of the set of containers, in particular above a conveying plane of this type.
The illumination devices can advantageously be pulsed illumination devices, such as for example flash lamps. These flash lamps can be triggered in particular by the image-recording device. It is advantageous for the illumination devices to have elements, such as in particular light-emitting diodes (LEDs). In this case light-emitting diodes of different colours (RGB) can also be used.
Furthermore, it is possible for the region in which the inspection device is arranged to be shaded, for example a casing is provided by which the sets of containers are transported.
In the case of a further advantageous embodiment the inspection device has an information output device, and in particular an image output device, which are suitable for the emission of values or signals respectively which are characteristic of a set of containers.
The present invention further relates to a method of producing sets of containers. In this case in a first method step a set is formed from a plurality of containers. In a further method step a film-like packaging material is applied to the containers, this film-like packaging material surrounding the containers at least locally. In a further method step the film-like packaging material is shrunk onto the containers. In a further method step the containers with the packaging material arranged on them are inspected for the shrinkage of the packaging material. In this way, the complete set of containers is first produced and then an inspection thereof is carried out. An inspection would also be possible after the packaging and before the shrinking of the packaging material.
It is advantageous for the set of containers to be inspected during the conveying thereof.
In the case of a further advantageous method at least one relative position of a first container of the set of containers with respect to a second container of the set of containers is detected. In addition or as an alternative, it is possible for at least one external surface of the set of containers to be inspected.
It is advantageous for an evaluation of this relative position also to be carried out. In this case it is advantageous for this measured relative position to be compared with a nominal position.
Conclusions on the correctness of a set of containers can advantageously be drawn from this comparison.
It is advantageous for a relative position of a container situated on the outside in the set of containers to be compared with a second container situated on the outside in the set of containers. This based upon the fact that, in particular, the containers situated on the outside are decisive for the straightness and flatness of the lateral faces and thus for the possibility of further processing. It is advantageous for a deviation of the relative position of a container with respect to another container to be compared with a nominal deviation or a nominal position respectively. In this case it is possible for a threshold value to be formed for this deviation and, if this threshold value is exceeded, for a further reaction to be carried out with respect to the production procedure and/or the inspected container. In this way, it is possible for a specific set of containers to be separated out in reaction to measurements of this type. In addition, the aforesaid set of containers can also be provided with a marking.

DESCRIPTION OF THE DRAWINGS

Further advantages and embodiments are evident from the accompanying drawings. In the drawings

FIG. 1 is a roughly diagrammatic illustration of an apparatus according to the invention for the production of sets of containers;

FIGS. 2 a, 2 b are two illustrations of a set of containers;

FIGS. 3 a, 3 b show two examples of possible deviations or defects of sets of containers;

FIG. 4 is a diagrammatic illustration of an inspection device;

FIG. 5 is a diagrammatic illustration of an optical measurement from above;

FIG. 6 a is an illustration of a measurement whilst using a single pack path;

FIG. 6 b is an example of the measurement in the case of two pack paths;

FIG. 6 c is an example of the measurement in the case of three pack paths;

FIG. 7 is a further diagrammatic illustration to demonstrate the measurement;

FIG. 8 is a further illustration to demonstrate a measurement;

FIG. 9 is a further illustration of the measurement with respect to FIGS. 7 and 8;

FIG. 10 is an illustration of the measurement whilst using a line scanner;

FIGS. 11 a, 11 b are two illustrations to demonstrate an inspection of an underside of the set of containers;

FIG. 12 is a further illustration for measuring the end faces of the set of containers;

FIG. 13 is an illustration to demonstrate a measurement value output, and

FIGS. 14 a to c are three illustrations of a shrinking device.

DETAILED DESCRIPTION

FIG. 1 is a roughly diagrammatic illustration of an apparatus 1 according to the invention. In this case a conveying device 6 is provided which guides or conveys the sets of containers along a pre-set conveying path. This conveying device can be designed in this case in the form of a conveyor belt or conveying chain. In addition, it would also be possible for the conveying device to guide or grip the sets of containers differently at different regions of the conveying path. In addition, the conveying device can be assembled from various units.
In this case it is possible for the containers (not shown in detail) to arrive already assembled in a group at a packaging device 2 and to be provided, for example to be wrapped, by the latter with a film-like packaging material. After this procedure the sets of containers 10 formed in this way with the packaging material are conveyed further through the conveying device 6 to the shrinking device 4. This shrinking device is advantageously a so-called shrink tunnel through which the sets are conveyed, in which case the shrink film is heated and rests close against the sets of containers 10 in this way.
An inspection device 8, which checks the sets of containers 10 and, in particular in this case, checks the result of the packaging and shrinking procedure, is provided downstream with respect to this shrinking device 4.
The reference number 16 designates a position detection device which detects a position of the sets of containers along the conveying path. The inspection device 8 can be triggered by this position detection device 16. The reference number 84 refers to an output device which emits at least one signal which is characteristic of a physical property of the set of containers, in particular of a deviation of at least one physical property with respect to a reference.
The reference number 18 designates a separation device which is suitable and intended for separating individual sets of containers out from the further processing. This separation can be carried out in this case in particular in reaction to a signal which is emitted by the inspection device and which displays the defectiveness of a set of containers 10.
The reference number 22 designates a group formation device which forms groups from containers, for example groups of two, groups of four, groups of six etc.
FIG. 2 a is an illustration of a set of containers 10. It will be seen that in the example shown in FIG. 2 a twelve containers 20 are assembled in a set of containers 10. The reference number 20 designates an individual container. The reference number 12 refers to the film-like packaging material which is arranged substantially around the containers.
The reference letters A, B and C designate the dimensions of the sets of containers. In this case it would be possible for the set to be made substantially cuboidal, but on account of the tapering aperture region of the containers the sets of containers are somewhat narrower at the upper end than at the lower end. The reference letter H refers to the tolerances for the position of an imprint. The reference number 14 designates an opening in the packaging material which is also referred to as an eye, and the reference letter G designates the tolerance for the central axis of this opening or the film eye respectively. The reference letters D and E designate shape tolerances for the offset.
FIG. 2 b is a side view of a set of containers, in which case a radius of the containers in the region of the closures is indicated with the reference letter G.
FIGS. 3 a, 3 b show two examples of defective sets of containers or of sets of containers assembled in a defective manner respectively. In the case of the illustration reproduced in FIG. 3 a it will be seen that the middle row of containers (indicated in this case by the broken lines) is shifted by a distance D with respect to a nominal position. A set of containers of this type can give rise to problems in stacking one above the other.
FIG. 3 b shows a further example of a defective assembly. It will be seen in this case that the middle row is offset with respect to the lower row both laterally to the left and the individual longitudinal rows are offset by the amount F in the vertical direction in this case. In addition, a set of containers of this type would be classified as defective and would be separated out accordingly.
FIG. 4 is a roughly diagrammatic illustration of an inspection or testing device for a set of containers 10.
This inspection device has in this case an observation device 82, such as for example a camera, which is arranged above the sets 10 of containers or the conveying path thereof respectively.
The reference number 92 designates illumination devices which also illuminate in particular the background of the set of containers 10 in order to achieve a stronger contrast in this way and in order to detect, in particular, the contours of the set of containers 10 which are particularly crucial.
The reference number 86 designates a lens member which, in particular, is a Fresnel lens. This Fresnel lens preferably has a very short focal length and thus allows the observation device 82 to be arranged comparatively close to the set of containers 10.
In the case of a preferred embodiment a telecentric observation of the set of containers 10 by the observation device 82 is carried out. In this way, it would be possible for example for a telecentric lens with a telecentric beam path towards the lens to be used. This would make it possible to detect articles, in this case the set of containers, without distortion of perspective. In addition, however, it would also be possible for a beam path to be used which is telecentric towards the image and which serves, in particular, the parallelization of the beam path. In this case the exit pupil lies at infinity, so that the beam cones strike the image plane substantially at a right angle. Finally, a telecentricity on both sides could also be used, i.e. the combination of a beam path towards the article and a beam path telecentric towards the image.
A telecentricity towards the image recorder is achieved by the optical element being a Fresnel lens with a focal length of 600 mm. A groove spacing of less than 1 mm is preferred, and of <0.5 mm is particularly preferred. The distance for the generation of telecentricity is 550 mm to the lens which can be a zoom with a focal length of from 10 to 40 mm. Lenses with a luminous intensity of better than 1:4, 1:2.8 are preferred. In this way, a usable telecentric image field diameter of approximately 350 mm is achieved.
It is advantageous for a distance between a top side of the set of containers and the image-recording device or an image-recording element respectively to be between 5 cm and 250 cm, preferably between 10 cm and 150 cm, preferably between 30 cm and 120 cm, and preferably between 40 cm and 120 cm.
It is advantageous for the illumination devices 92 to be arranged in this case on the same side with respect to the sets of containers 10 as the observation device, i.e. also above in this case. In this way, it is possible to prevent light from the illumination devices 92 arriving directly at the observation device 82.
FIG. 5 is a further illustration to explain the method. It will be seen that in this case the observation device 8 is arranged centrally above the set of containers 10 (at least at the time of the image recording). The reference number 20 again designates the containers. The reference number 20 a designates an aperture or closure region of the containers. In this case, therefore, the image-recording device, which in this case is directed vertically downwards and which—in particular triggered by a sensor, such as a light barrier—detects each set of containers from above, is attached above the pack path. The limits of the sets of containers and also the position of the container heads 20 a can be detected by suitable image analysis. In addition, the absence of individual containers 20 can be established in this way.
In the case of the illustration reproduced in FIG. 6 a a lateral observation by image- recording devices 82 a, 82 b additionally takes place. In this way, the sides can be observed and/or projected upwards completely or in part (optionally also by a suitable mirror lens).
FIG. 6 b shows a further arrangement in which two sets of containers are conveyed adjacent to each other in the direction of the conveying path T. With this design an image-recording device 82 is arranged in this case between these two sets of containers and two further image- recording devices 82 a, 82 b or a corresponding mirror lens is arranged in each case on the two sides of the sets of containers.
FIG. 6 c reproduces an illustration in which three sets of containers are conveyed parallel or adjacent to one another respectively in the conveying direction T. In this case one image-recording device 82 is arranged above the middle set of containers and two further image- recording devices 82 a, 82 b are arranged on the two sides.
FIGS. 7 and 8 reproduce a further illustration to demonstrate the optical measurement. In this case beam-reversing elements 96 or mirrors respectively are provided, which make it possible for the entire lateral faces of the set of containers 10 to be capable of being imaged. In this way, as mentioned above, a complete image of the lateral faces can be assembled from regions imaged piece-wise. In this case it would also be possible for the images of the lateral faces also to be imaged onto the image-recording device 82. For this purpose, semi-transparent mirrors could be used or a multiple illumination could also be carried out with light of different wavelength. The sets of containers 10 are conveyed in this case at a right angle to the plane of the figures. The opening of the packaging material illustrated here is not necessarily present.
FIG. 8 reproduces an illustration of this type, in which case the base regions of the sets of containers can be detected in each case by the two reflecting or mirror elements 96. Distortions possibly caused by the lens can advantageously be corrected in this case by suitable software. In this way, it would be possible for the respective lateral regions of the sets of containers also to be recorded, in which case further mirror elements 96 (not shown) could also be provided.
FIGS. 9 and 10 show a further design. In the case of this design an observation device 82 in the form of a line scanner 182 is used. This line scanner 182 is likewise arranged in a stationary manner in this case and the set of containers moves along the conveying path T relative to this line scanner 182. This line scanner can likewise assemble a complete image from individual columns of the side view. In addition, it would be possible in this case for critical areas, such as for example the welding of the lateral lower film tab, to be capable of being checked in addition or as an alternative for its quality with a capacitive sensor.
FIG. 10 is a corresponding view from above, in which case two line scanners 182 of this type are used.
FIGS. 11 a, 11 b reproduce an illustration on the checking of the base welding. In this case too, use can again be made of an observation device 82, such as for example also a capacitive sensor or even a line scanner, which is arranged in this case between two conveying devices 6 and checks the container during the transfer from the left-hand conveying device for example to the right-hand conveying device 6. In this case it is possible for the observation device to check the sets of containers 10 directly, but it would also be possible for the beam path, as shown in FIG. 11 b, to be guided by way of a reversing device such as a mirror.
FIG. 12 explains a further observation of the sets of containers, in which case in particular the end faces can also be projected into the receiving region of a camera by way of the two observation devices 82 a and 82 b. In this case two cameras are provided which observe the pack path obliquely from above.
In addition, it is also possible for only one camera also to be used by way of optical elements (in particular mirrors) and for the necessary views to be projected into the illustration region of this camera or the (at least one) camera respectively.
FIG. 13 reproduces an illustration of a possible image recording. In this case the line L shown in the upper partial image can show the actually measured deviation from an ideal packaging dimension, for example a lateral face. The two lower lines can represent the corresponding deviations in the two other directions. In these illustrations threshold values can be formed which are still regarded as being acceptable. If these are exceeded, an information output device can inform the user that the set of containers in question has been packaged defectively and for this reason has to be separated out for example. In this way, a separating device arranged downstream could separate out the respective set of containers in reaction to such a result. In addition, it would be possible for a processing unit situated in the conveying direction of the set 10 of containers to be regulated or for the operation thereof to be modified in a manner dependent upon such a result. It is advantageous, however, for a separation of this type to take place (fully) automatically.
FIGS. 14 a to 14 c reproduce three illustrations of the shrinking device 4. This shrinking device is designed in each case in the form of a so-called shrink tunnel in this case. The observation device 8 is provided directly adjoining the shrinking device.
FIG. 14 b shows a further embodiment of the shrinking device 4. In this embodiment two rows of sets of containers are conveyed parallel to each other. The reference numbers 24 and 28 refer to stressing devices which are arranged at the side and which act upon the set of containers with hot air from the side. A further stressing device 32, which allows the two sets of containers to be acted upon from both sides in each case, is situated between the conveying paths of the sets 10 of containers. The sets of containers are also acted upon with hot air from below by means of a further stressing device 26. It is preferable for a distance between the lateral stressing devices 24, 28 and 32 to be capable of being set or altered respectively. In addition, it would be possible for a vertical level of the individual stressing devices 24, 28 and 32 with respect to the conveying device or the stressing device 26 respectively to be capable of being altered.
FIG. 14 c reproduces a further illustration of a shrinking device 4. In this case too, three stressing devices 24, 28 and 26 are again provided which act upon the sets of containers 10 with the packaging material arranged thereon with hot air from the sides as well as from below.
The Applicant reserves the right to claim all the features disclosed in the application documents as being essential to the invention, insofar as they are novel either individually or in combination as compared with the prior art.

LIST OF REFERENCES

1 apparatus according to the invention
2 packaging material
4 shrinking device
6 conveying device
8 observation device
10 set of containers
12 packaging material
14 opening in the packaging material
16 position detection device
18 separation device
20 individual container
20 a container heads
24, 26, 28, 32 stressing device
22 group imaging device
82 observation device/line scanner
82 a, 82 b image-recording devices
84 output device
86 lens member
92 illumination devices
96 mirror elements
A, B, C dimensions of the sets of containers
H tolerance for imprint
G tolerance for central axis of the opening
D, E shape tolerances for the offset
F amount of the shift
T conveying path
L line

Claims

1. An apparatus (1) for the production of sets of containers (10), wherein the apparatus has a packaging device (2) which wraps a plurality of containers (20) at least in part with a film-like packaging material (12) and thus forms a set of containers (10), with a shrinking device (4) which shrinks the packaging material (12) which wraps the containers (20) at least in part, with a conveying device (6) which conveys the containers (20)—wrapped by the packaging material (12)—in a pre-set conveying direction, and with an inspection device (8) which inspects the containers (20)—wrapped at least in part by the packaging material (12)—after the shrinking procedure.

2. The apparatus (1) according to claim 1, wherein the inspection device (8) is arranged downstream of the shrinking device (4) in the conveying direction (R) of the containers (20).

3. The apparatus (1) according to claim 1, wherein the inspection device (8) has an image-recording device (82) which is suitable and provided for recording images of the set (10) of containers.

4. The apparatus (1) according to claim 1, wherein the inspection device (8) is suitable for detecting a relative position of at least one container (20) of the set of containers (10) with respect to at least one further container (20) of this set of containers (10).

5. The apparatus (1) according to claim 1, wherein the apparatus (1) has a position detection device (16) which detects a position of the containers wrapped by the packaging material in the conveying direction.

6. An inspection device (8) for the inspection of sets of containers, wherein the sets of containers (10) have a plurality of containers (20) which are wrapped by a packaging material, with an image-recording device (82) which observes the sets of containers (10), wherein the inspection device (8) has an output device (84) which emits at least one signal which is characteristic of a relative position of at least one container (20) of the set of containers (10) with respect to at least one second container (20) of this set of containers (10) and/or which signal is characteristic of at least one external surface of the set of containers (10).

7. The inspection device (8) according to claim 6, wherein the image recording device (82) is arranged in such a way that it observes the set of containers (10) from above.

8. The inspection device (8) according to claim 6, wherein the inspection device (8) has at least one lens member (86) which is arranged between the set of containers and the image-recording device (82).

9. The inspection device (8) according to claim 6, wherein the inspection device (8) has at least one beam deflection element (96) which allows at least one lateral face of the set of containers to be observed.

10. The inspection device (8) according to claim 6, wherein the inspection device (8) has at least one illumination device (92) for illuminating the set of containers (10) during the inspection.

11. A method of producing sets of containers with the steps of:

forming a set from a plurality of containers (20);

applying a film-like packaging material to the containers (20), wherein this film-like packaging material (12) surrounds the set of the containers (10) at least locally;

shrinking the film-like packaging material (12) onto the containers (10);

inspecting the containers (20) with the packaging material arranged on them for the shrinkage of the packaging material (12).

12. The method according to claim 11, wherein at least one relative position of a first container (20) of the set of containers (10) with respect to a second container of the set of containers (10) is detected.