The present invention relates to an inspection apparatus by means of which vessels may be examined for defects. The invention further relates to a production unit by means of which these types of vessels are processed, and which contains an inspection apparatus according to the invention. Lastly, the present invention encompasses an inspection method by means of which vessels may be examined.
Vessels such as cans and bottles which are used to hold foods, chemicals, medicaments, and other materials must be examined for defects prior to filling and marketing in order to ensure that on the one hand the filling process proceeds without problems, and that on the other hand the contents of the vessels are not spoiled or impaired with respect to quality, and leakage of liquids is reliably prevented.
Frequently, vessels such as cans are shaped in the opening area by means of known shaping processes so that flanging is achieved on the vessel neck. This flanging is particularly suited for affixing a sealing closure foil or other closure element thereto, for example a valve. This requires that the flanging has no defects. To determine at an early time whether the shaping process has left damage on the can, or also whether bottle necks, which likewise have a bead-like opening enlargement on which bottle caps, for example, may be placed, are damaged, the bottles or cans are usually examined immediately after production. Known production methods use image recording technologies which enable the sensitive bottle or can neck to be recorded from the front, using image recording processes. It is known that when the bottles or cans leave the preceding processing unit, they are discharged from the unit and in the horizontal position are moved past a camera. The bottles or cans are fixed in a cup-shaped receptacle strictly by gravitational force, so that they are positioned only at the support point with a low level of accuracy and are present on the moving conveyor belt as a function of diameter in relation to the position of their longitudinal axis, which is disadvantageous for high-resolution image recording. In particular, minute damage such as scratches in the paint or tiny dents in the flanged rim, which require high image resolution, may be sufficient for liquids to escape from the vessel which is not precisely closed, or for oxygen, for example, to enter the vessel and adversely alter the contents by oxidation, for example.
The aim of known image recording processes is to image the bottle neck in frontal recordings; as the result of undercuts that are formed by flanged rims or bottle neck beads, areas situated beneath the plane of the bottle opening are not imaged or only inadequately imaged, and thus cannot be monitored.
Based on this prior art, there is a need to provide an improved inspection apparatus for examining vessels which allows enhanced image quality for determining defects in vessels. This object is achieved by the inspection apparatus having the features of Claim 1.
Furthermore, there is a need to provide an improved production unit by means of which vessels may be produced and processed, and which allows inline images of the vessel having enhanced recording quality to be acquired, it being desirable to capture not only a top view of a plane of the vessel neck, but also to achieve the most comprehensive imaging possible. This object is achieved by the production unit having the features of Claim 7.
A further object is to provide an improved inspection method which allows the quality of vessels to be realized directly in production in a precise and reliably reproducible manner. This object is achieved by the inspection method having the features of Claim 10.
Corresponding refinements of the apparatus and of the method are set forth in the respective subclaims.
One embodiment of an inspection apparatus according to the invention is used in the examination of vessels which are fixedly mounted on a processing machine.
The term “vessel” below is understood to mean a can which may be filled with a spray or some other liquid, for example, and which for this purpose is shaped in a processing machine such as a necking machine. Such cans are primarily made of metal. However, “vessel” may also be understood to mean a bottle, also glass or plastic bottles, as well as other containers such as vases and the like.
In this regard, the term “processing” may be understood to mean shaping as well as the application of a surface coating, smoothing the surface, or, in the case of glass processing, for example grinding or any other type of post-processing of a blank or a preform which is to be formed to produce the vessel.
The inspection apparatus of the present invention is used to determine damage of the surface of these types of vessels by image recording; scratches in a paint coating, as well as dents, flaked-off material particles, cracks or fissures, and other damage of the interior and exterior of the vessel may be understood as damage.
The inspection apparatus has a stand to which a camera, which is connected to an optical component such as one or more lenses or some other suitable optical component, is fastened. These types of cameras are known to those skilled in the art. The camera has a conventional image processing unit. The image processing unit may be connected, in a manner known to those skilled in the art, to further data-processing or image-processing units, for example for enlarging or storing recorded images or for making comparisons using data processing units, also possibly including coupling to a database in which comparative images of ideal or damage-free vessels are stored, so that when damage is detected and subsequent image comparison is carried out, the defective vessel may be immediately removed from the production unit or a conveying device coupled thereto.
The camera and an associated illumination device are held by a holding device which is connected to the stand. The optical component of the camera defines an image recording axis which faces in the direction of the vessel to be inspected, and which for this purpose is explicitly in a so-called “inspection position.” In this position the central longitudinal axis of the vessel to be inspected is aligned with the recording axis of the camera.
The inspection apparatus also has a component which is movable with respect to the stand, i.e., mobile. This component includes a retaining tube, inside of which a second optical component is situated. The retaining tube is situated coaxially with respect to the recording axis in an area between the camera and the vessel, and is movable parallel to the axis, in the direction of the vessel. The opening cross section of the movable retaining tube is larger than a maximum outer circumference of a section of the vessel to be inspected. While the vessel to be inspected is in the inspection position, the inspection apparatus is transferred into an image recording configuration wherein the retaining tube is moved over the vessel, so that at least the section of the vessel to be inspected is surrounded by the retaining tube. The beam path extends from the illumination device to the section of the vessel to be inspected, and from there extends over the second optical component to the first optical component of the camera.
In one embodiment of the invention, the holding device may be a jacket tube made of a metal, metal alloy, plastic, or fiber composite material, the central longitudinal axis of the jacket tube being aligned with the recording axis of the camera, and thus, also with the central longitudinal axis of the vessel in the inspection position. The outer circumference of the jacket tube is smaller than the opening cross section of the retaining tube, so that when the retaining tube is withdrawn from the image recording configuration it partially or completely surrounds the jacket tube. The next vessel to be inspected may then occupy the inspection position in an unhindered manner.
While the first optical component which is coupled to the camera is usually a lens or an arrangement of lenses, the second optical component may be a mirror, in particular a mirror having a concave curvature or a parabolic mirror, having a central through opening. This mirror situated in the retaining tube advantageously allows the vessel to be imaged all the way around, i.e., also on its side walls. The mirror has a through opening, and during the image recording is pushed to the desired extent across the vessel together with the movable mounting. The curvature of the mirror is configured in such a way that the optical system of the camera may also record the undercuts and walls via the mirror.
Alternatively, as a further optical component an endoscopic optical system may be situated in the retaining tube, which as the result of mounting in the retaining tube is held parallel to and centered with respect to the central longitudinal axis of the retaining tube. One end of the endoscopic optical system faces toward the camera. The endoscopic optical system is not connected to the camera, but a recording area of the camera is adjusted on the end face at the end of the endoscopic optical system via the first component or the lens in such a way that an image transmission from the endoscopic optical system to the camera occurs. The second end of the endoscopic optical system is oriented toward the vessel, which is in the inspection position, the vessel opening of which faces the endoscopic optical system in order to allow the second end to submerge into the interior of the vessel.
The present inspection apparatus is advantageously suitable for already being integrated inline in the production process and taking image recordings of the vessel at the end of the processing line when the final processing steps are concluded, while the vessel is still fixedly mounted on the processing machine. It is thus possible to create high-resolution, precise images which reveal the most minute damage to the vessels. A production unit for producing vessels, which includes at least one processing machine for processing the vessels, therefore has a moving conveying device that moves the vessels, which, however, are fixedly mounted on the conveying device. The vessels, fixedly mounted on the conveying device, pass by multiple processing stations in the processing machine, such as shaping devices, without the vessels having to be turned over.
In addition, the production unit according to the invention includes an inspection apparatus by means of which the vessel quality, as described above, may be examined after the processing. The term “vessel quality” is understood to mean that no damage is present on the surface, whereby the damage may range from cracks to scratches to material flaking and dents.
In the production unit according to the invention, the inspection apparatus is integrated by means of a stand in such a way that the camera, having an appropriate image processing device and an optical component which is connected to the camera, is able to suitably produce comprehensive images not only of the top view of the vessel neck, but preferably also of undercuts at inner or outer wall areas situated behind the neck.
If only images of the can neck or bottle neck or the opening plane thereof are to be recorded, a simple inspection apparatus may be used which includes a holding device, preferably a jacket tube made of metal, in which the camera is fastened to an illumination device. The beam path of the camera and the beam path of the illumination device correspondingly extend toward an image recording opening in the metal tube so that the exiting light beam may properly illuminate the object to be examined and the camera may take pictures.
According to the invention, the inspection apparatus is integrated inline in the production unit, and may be situated at the end of the processing machine. This has the advantage that the processed vessels are still fixedly mounted on the conveying device, and therefore in order to achieve optimal image quality do not wobble when images are produced.
The inspection apparatus, which includes the holding device which is fastened to the stand, and in which the camera together with the first optical component and the illumination device are fastened, is situated in the processing machine in relation to a vessel to be inspected, which is in an inspection position, in such a way that the camera together with the first optical component points along a recording axis in the direction of the vessel to be inspected, and the recording axis is aligned with a central longitudinal axis of the vessel in the inspection position.
The inspection apparatus may advantageously be coupled to the processing machine via a control device in order to control the inspection apparatus in coordination with the conveying device in such a way that the image recording for examining the vessel quality takes place during a holding phase of the conveying device, with the vessel to be inspected in the inspection position. This holding phase is specified by a time period that is necessary for a vessel to be processed by the processing machine. This holding phase, together with the fixed mounting of the vessels on the conveying device and the stationarily mounted camera, allows optimal image quality.
An inspection method for examining the quality of a vessel after it has been processed, which may be carried out on such a production unit, therefore includes the fastening of the vessels to the movable conveying device of the processing machine so that the vessels may be processed at multiple processing stations of the processing machine. In addition, in the processing machine the inspection apparatus in each case advantageously examines one of the vessels, which is in the inspection position in which the central longitudinal axis of the vessel is aligned with the recording axis of the camera. For the image recording of the corresponding vessel to be examined, the inspection apparatus is controlled by the control device in coordination with the conveying device, so that the inspection apparatus may examine the vessel, which is in the inspection position, when the conveying device is stopped. Such a holding phase is specified by the processing time of the vessels in the processing stations. The longest processing step determines the duration of the holding phase, which is usually very brief.
In order to take further pictures and also image the interior of the vessel or lateral wall sections and undercuts, as described above, an inspection apparatus may be used which has a movable component in addition to the static component.
According to this method procedure, the movable part components of the inspection apparatus, and thus the retaining tube having the second optical component, move(s) into the image recording configuration, parallel to the axis with respect to the recording axis in the direction of the vessel to be inspected, so that the section of the vessel to be inspected is situated in the retaining tube; however, the retaining tube may also be guided over the entire vessel.
The beam path correspondingly extends from the illumination device to the section of the vessel to be inspected, and from there extends over the second optical component to the first optical component of the camera.
It is particularly advantageous when the movable component is a retaining tube in which either a mirror, such as a parabolic mirror, or some other mirror having a concave curvature is situated, and which has a central through opening and in this regard may be guided over the object from which the image recording is to be produced. Undercuts may be easily recorded by moving the mirror along the vessel to be examined, so that the camera may now record the vessel not only in strictly a top view, but also indirectly in a comprehensive side view via the mirror optical system in the retaining tube. To record a comprehensive internal view of the vessel, a retaining tube having an endoscopic optical system may advantageously be used which may be guided into the interior of the can to be examined or the bottle to be examined while the retaining tube accommodates the vessel to be inspected, so that it is possible to examine practically any internal geometric shape.
These and other advantages are explained by the following description, with reference to the accompanying figures. Reference to the figures in the description is used to support the description and simplify understanding of the subject matter. Objects or parts of objects that are essentially identical or similar may be provided with the same reference numerals. The figures are merely schematic illustrations of exemplary embodiments of the invention, and show the following:
The invention relates to an inspection apparatus by means of which a vessel, such as a can, may be checked for shape and any production defects at the end of production. According to the invention, this check is made inline during ongoing production, wherein each vessel or each can produced is checked.
In the present context, a vessel or can is understood to mean a container having a longitudinal extension which, as shown in
In order to now be able to carry out contactless final inspection on a processing machine, such as a necking machine 10 in
The inspection apparatus 1 has a stand 9 to which a jacket tube 4 as a holding device for the camera 2 and the illumination units 5 is affixed. The jacket tube 4 may be a metal tube, for example a steel tube, but may also be made of a plastic or a fiber composite material. The camera 2 together with an associated optical component 3 as well as the illumination units 5 are accommodated in the jacket tube 4, a recording area of the camera 2 and the beam path thereof extending outwardly from an opening 4′ in the jacket tube 4 facing away from the stand 9. As shown in
The movement of the vessels through the processing machine by means of the conveying device is not continuous, but, rather, takes place intermittently due to the processing time for a vessel, so that each vessel in succession, with its longitudinal axis in the recording axis A-A of the camera 2 during the time period specified by the processing, briefly comes to a stop in order to be checked at that location. The inspection apparatus 1 is controlled in such a way that the examination sequences of the inspection apparatus 1 proceed in coordination with the holding pattern of the conveying device 11. For this purpose, the inspection apparatus and the conveying device may be coupled via a control device, not illustrated. By use of the camera 2 situated in the jacket tube 4, it is possible to record only the top view of the vessel 20; obscured areas behind outward curvatures such as the flanged rim 21 cannot be recorded in this manner.
To also be able to record these obscured areas via the camera 2, the inspection apparatus 1 according to the invention includes a supporting element 7′ which is movable parallel to the longitudinal axis of the jacket tube 4, and which, as shown in
A circumferential mirror element 6 having a through opening 6″ is situated in the retaining tube 7, the diameter of the mirror element being large enough that the retaining tube 7 together with the mirror element 6 is also able to move over a maximum cross section of the vessel 20 to be examined. The mirror element 6 may have a design that is different from a parabolic mirror element, for example, the through opening 6″ being situated in the middle and centered with respect to the axis A-A.
The retaining tube together with the mirror element situated therein, as well as the jacket tube and the supporting element through opening, do not necessarily have to have circular cross sections. As a function of a cross-sectional shape of the vessels to be inspected, retaining tubes together with mirror elements having corresponding cross-sectional shapes may be selected, and the jacket tube and the corresponding through opening in the supporting element may also be adapted in a similar manner.
The vessel 20 shown in
The integration of such an inspection apparatus into the production unit 10 (see
Number | Date | Country | Kind |
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10 2010 032 410.8 | Jul 2010 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP11/03716 | 7/25/2011 | WO | 00 | 4/7/2013 |