METHOD AND APPARATUS FOR DETECTING CONSTRUCTION FAULTS IN CONTAINERS MADE FROM BLANKS, AND PACKAGE BLANK

Abstract: A method and apparatus for detecting construction faults in a container or a container package assembled from a two-dimensional blank. Portions (41, 42, 42) of the container or container package (21) have areas of contrasting colours (61, 62, 46) which are optically scanned, the scan results are passed to an electronic control unit (51) for comparison with stored parameters, and if the scan results fall outside the parameters the container is deemed to be faulty.

Description: METHOD AND APPARATUS FOR DETECTING CONSTRUCTION FAULTS IN CONTAINERS MADE FROM BLANKS, AND PACKAGE BLANK This invention relates to containers and to packaging for containers, and in particular to containers and packaging which are formed by folding and assembling two dimensional blanks. Containers and container packaging can typically be formed from paper or cardboard blanks which are folded into the required three dimensional shape, for example a box, or a sleeve which may be used to hold together a plurality of containers such as plastic pots or bottles. To assist the formdation of a box, or sleeve, the blank as well as having portions that correspond to the walls or panels of the container, will include tongues and/or flaps which may overlap and are secured together to hold the blank in its three dimensional shape. These flaps or tongues may be fixed together by means of a layer of adhesive applied between the overlapping flaps, or by means of mechanical locks. A typical mechanical lock comprises a tab in one flap which engages in an aperture in the other tab. A problem aasociated with wrapping pre-filled containers in container sleeves on packaging machines is that the ends of the sleeve, which may be secured together as described above, may not be correctly attached to each other. For example when held together by adhesive the two overlapping end portions may be secured on a skew relative to each other, or in the case of a mechanical lock the two ends may not be secured at all, or may only be partially locked together. The result of improper assembly of the sleeve may be that the sleeve falls apart and the pre-filled containers burst spilling their contents onto the packaging machinery. Such accidents are messy and costly in lost production time. Accordingly there is provided a method of detecting construction faults in a container or a container package, assembled. from a two dimensional blank. In said method predetermined portions of the container or container package have areas of contrasting colours which are optically scanned, the scan results are passed to an electronic control unit for comparison with stored parameters, and if the scan results fall outside the parameters the container is deemed to be faulty. The invention is applicable to both containers formed from folded blanks, and to container packaging such as sleeves which are also formed from folded blanks. Optical scanning includes laser scanning as well as the use of cameras including cameras in which the optical field is split into pixels. The term "contrasting colours" includes both black and white as well as speckled or hatched areas in which the colour density can be altered by altering the density of the cross-hatching or spots. Any combination of contrasting colours may be suitable e.g. black and white or blue and white. The electronic control unit may be a computer having a memory programmed with stored parameters relating to the arrangement of the contrasting areas for a well assembled container, or container package. The areas of contrasting colour may be applied to portions of the blank which are utilised for attachment to other co-operating portions of the blank to form the container. The blank may include at least one pair of tongues or flaps which in the assembled container., or container package are secured together in overlapping relationship, either by adhesive or by mechanical locking means, and the contrasting coloured areas may be lines on the flap or tongue which extend transversely of the direction of overlap, or the locking means may be coloured or include areas of contrasting colour. Preferably the locking means is as a tab in one flap or tongue which engages in an aperture in the other of the tongue or flap. Preferably the lines and coloured areas are blue and the adjacent packaging sleeve areas are white. The detection of a faulty container or pack can be utilised to operate a reject mechanism to separate the faulty containers from 'good' containers to avoid problems downstream of the packaging line. The invention further includes apparatus for assembling blanks into containers, or container packages, and which includes an optical scanner for detecting predetermined areas of contrasting colour on the container, and sending a signal to an electrical control unit for processing, the electronic control unit comparing the scanned signal with predetermined parameters and if the signal falls outside said parameters the control unit operates a reject means to separate the faulty package or container from packages within said parameters.. The invention also includes a packaging blank for formation of a container or a container package, the blank having at least one pair of tongues or flaps which are seamed together in overlapping relationship to form the container, and at least one of the pair of tongues or fla DS has as area of contrasting colour thereon which is readable by a optical scanner to enable assembly faults to be detected. The invention will be described by way of examples and with reference to the accompany drawings in which; - Fig. 1. is a schematic drawing of an apparatus according to the present invention, Fig. 2. is part view of a blank showing the free end portions, Fig. 3. is an end view of a sleeve formed from the blank, Fig. 4. is an external view of an adhesive secured flap in an acceptable configuration, Fig. 5. is an external view of the adhesive sealed flaps in an unacceptable configuration, Fig. 6. is an external view of the mechanical lock in an acceptable condition, Fig. 7. is an external view of a partially secured mechanical lock which would be unacceptable, and Fig. 8. is an external view of a totally failed mechanical lock. With reference to Fig. 1 there is shown an in-line continuous motion sleeving machine 10 which is intended for wrapping a sleeve around a product, such as a food package, or a number of containers such as yoghurt pots or bottles . The product 11, e.g. a number of yoghurt pots, is moved down the apparatus by a conveyor 12 having drive bars 13 for pushing the package through the apparatus. The driv e bars are set at a pitch as desired for the product to be sleeved. The conveyor belt 12 is driven by an electric motor 14 through a series of pulleys and belts 15. The product is 11 placed onto the conveyor belt 12 by means of an automatic feed (not shown) or by hand. Downstream of the package feed there is located a hopper 17 for feeding flat sleeve blanks 21 into the apparatus for assembly around the product 11. The blanks 21 which are shown in part of Fig. 2 have foldlineε, cuts and apertures formed therein. An articulated arm 18 with a sucker 19 thereon picks up a blank from the hopper and drops it into a moving product package 11. The package 11 and respective sleeve 2.1 are moved past a pair of spaced apart blades 22 which rotate about a horizontal axis. The blades 22 are spaced apart by a distance just greater than the width of the package so that the blades fold unsupported portions of the blank downwards to form the sides of the sleeve. The package then moves on to two further folding stations 24 and 25 where the two free end portions of the sleeve are folded into overlapping relationship. A suitable mechanism for this is disclosed in British Patent Application 2281 549. The package now enclosed within the folded sleeve passes to a locking station 36 for the sealing together of the two end portions . The two portions could be secured together by either mechanical lock or by an adhesive closure. With reference to Fig. 2 and Fig. 3, there is shown in Fig. 2 the end portion 31, 32, of the blank 21. The blank 21 comprises .of a subsequently square central panel 33 which is connected through transverse foldlines 34 to a pair of substantially square sidewalls 35, 36. The sidewalls 35, 36 each have a transverse foldline 37 at approximately the mid-length of each sidewall. The sidewalls 35 and 36 are connected through fold lines 38 to the respective and portions 31 and 31 which are folded towards each other to form an end wall 40 opposite the central panel 33. Cut-outs 39 may be provided on the fold lines 38 to accommodate product containers enclosed in sleeve 21 Each end portion 31, 32 includes a flap or tongue portion 41, 42 respectively which in use overlaps the other flap or tongue portion to secure the two end portions 31, 32 together. The mechanical lock is formed by a tab 43 in one flap 41 engaging in an aperture 45 in the other flap 42. The aperture 45 may be rectangular, or preferably may be trapezoidal as shown in dotted outline 45a . The tab 43 is lozenge shaped and is cut from the flap 41 and is hinged to the flap 41 by a fold line along one side 44. The triangular end portions 46 of the tab flex to allow it to be pushed through the aperture 45. A trapezoidal aperture 45a guides the tab into a lock position more readily. On the apparatus 10, this tab 43 is pushed through the aperture 45 by a reciprocating vertical pin 37. The assembled sleeve and package 11 is then moved to a takeoff conveyor 38. An optical camera 50 is located downstream of the locking station 37 for viewing the now locked'-ends of the sleeve. The camera could b a CCD linear element camera in which the image is divided into pixels. The camera is electrically connected to the apparatus electronic control unit 51 which includes a micro processor . The control unit 51 in turn is connected to a reject mechanism 53 which removes or separates faulty packages from the flow of assembled packages on to the take-off conveyor 38. As can be seen in Fig. 2, the end portions 31, 32, of the sleeve 21 are marked on the surface which in use will be external to the assembled package. The flap 41 has a transverse thick line 61 formed in a contrasting colour to the rest of the sleeve. The tab 43 has its triangular end portions 46 also marked with contrasting colour. The other flap 42 is also formed with a transverse thick line 62 in the same or a different contrasting colour. When the sleeve 21 -is assembled the two flaps 41, 42 should come together so that the two white lines 61, 62 are substantially parallel and a desired distance apart. The assembled end portions of the sleeve are shown in Fig. 4. as viewed in the direction of arrow A in Fig. 3. The parameters relating to distance apart and parallelism can be put into the memory of the micro processor in the control unit 51 so that if the camera 50 observes a package having lines 61, 62 which are skewed and non parallel as shown in Fig. 5., then the control unit 51 operates the reject mechanism 53 to push the faulty package off the conveyor system. Fig. 6. similarly shows the tab 43 when making a good engagement with the aperture 45, as viewed from the direction of arrow A in Fig. 3. The two contrasting coloured end portions 46 are hidden under the edges of the operative 45. Fig. 7. shows the tab 43 when partially secured. The one end portion 46 is visible whilst the other coloured end portion 46 is hidden by the edge of the aperture 45. Fig. 8. shows a situation in which the tab 43 is merely lying in the place of the flap 41. The different situations which result in different contrasting colour . configurations can be programmed into the micro processor memory, so that the camera 50 can observe the packages with faulty mechanical locks which are then removed from the apparatus. It will be appreciated that the particular contrasting colour markings are illustrative only ..and that different markings could be used for the same mechanical locks, or adhesive locks or for different locks. All that is required is that the camera can observe different contrasting configurations on the sleeve depending upon the state of the lock, for comparison with known parameters .

Claims: Claims . 1) A method of detecting construction faults in a container or a container package assembled from a two dimensional blank, in said method predetermined portions of the container or container package have areas of contrasting colours which are optically scanned, the scan results are passed to an electronic control unit for comparison with stored parameters, and if the scan results fall outside the parameters the container is deemed to be faulty. 2. A method as claimed in Claim 1 in which areas of contrasting colour are applied to the portions of the blank which are utilised for attachment to other cooperating portions of the blank to form the container. 3. A method as claimed in claim 2 in which the blank includes at least one pair of tongues or flaps which in the assembled container or container package are secured- together in overlapping relationship, wherein each tongue or flap has a line in contrasting coloμr formed thereon extending transversely to the direction of overlap and after assembly the lines are scanned for the distance therebetween and parallelism. 4. A method in claim 2 wherein said line extends across the full width of each flap. 5. A method as claimed m claim 2 or claim 3 in which the blank includes at least one pair of tongues or flaps in which the assembled container or container package are attached in overlapping relationship, and one of said pair of tongues or flaps has at least one tab attached thereto which is engageable in a respective aperture in the other of said pair of tongues or flaps to lock said pair in overlapping relationship, where said tab has said areas of contrasting colour thereon and after assembly the lock is scanned for detection of the coloured areas. 6. A method as claimed in claim 5 in which the tab has end portions which are foldable to enable the tab to pass through said aperture the tab then preventing separation of two tongues or flaps, wherein the areas of the contrasting colour comprise the foldable end portions of the tab, which are detectable if the tab is not properly engaged in the respective aperture. 7. A method of removing faulty containers or container packaging from a container or container package assembly- line, in which container or container package construction faults are detected by a method as claimed in any one of claims 1 to 6, and in which the electronic control unit operates a reject mechanism to separate the faulty containers from those containers falling within said parameters . 8. A packaging apparatus for assembling blanks into containers, or container packages, and which includes an optical scanner for detecting predetermined areas of contrasting colour on the container and sending a signa] to an electrical control unit for processing, the electronic control unit comparing the scanned signal with predetermined parameters and if the signal falls outside said parameters the control unit operates a reject means to separate the faulty package or container from those packages within said parameters. 9. A packaging blank for formation of a container, or for assembly into a container package, the blank having at least one area of contrasting colour thereon which is detectable by an optical scanner such that the blank can be used in a method according to any one of claims 1 to 8. 10. A packaging blank for formation of a container or a container package, the blank having at least one pair of tongues or flaps which are sealed together in overlapping relationship to form the container, and at least one of the pair of tongues and flaps has an area of contrasting colour thereon which is readable by an optical scanner to enable assembly faults to be detected. 11. A blank as claimed in claim 10 wherein each tongue or flap has a line in a contrasting colour formed thereon extending transversely to the direction of overlap so that after securing one tongue in overlap with the other tongue the two lines are visible externally of the container or container package. 12- A blank as claimed in Claim 10 or claim 11 wherein the one tongue has a tab therein which can be folded out of the plane of said tongue to engage in an aperture in the other tongue, and said tongue has at least one area of contrasting colour thereon to enable the engagement of the tab in the apertuere to be detected. 13. A blank as claimed in claim 12, where the tab has end portions which are foldable to enable the tab to push through said aperture and the foldable end portions are coloured in said contrasting colour. 14. A packaging blank substantially as described herein. 15. A method of detecting faults in assembled containers or container packages, and which is substantially as described herein.

Inventors: FISHER GARY AUSTIN, FISHER, GARY, AUSTIN
Applicants: FISHER GARY AUSTIN, FISHER MATTHEWS LTD, FISHER, GARY, AUSTIN, FISHER-MATTHEWS LTD.
Application year: 1997
Main classification: B65B57
IPC codes: B65B57