MXPA06010358A - Easy open can end and process of making - Google Patents

Abstract

An easy open end for a container includes an end panel (60) having a score defined therein that defines a removable end panel portion. The score is preferably notched to define a bottom edge having a continuous V-shaped recess. A first double fold (134) is defined adjacent to and positioned radially inward from the score (81) that defines beneath the score a first outwardly projecting extending cut protection bead (138). A second double fold (136) is defined adjacent to and positioned radially outward from the score (81) that defines beneath the score a second inwardly projecting cut protection bead (140). The end panel is elastically deformed in an area near the score so as to define a concave depression (144) about the score, which provides enhanced cut protection.

Description

ZW), Eurasian (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), For two-letter codes and other abbreviations, refer to the "Guid- European (AT, BE, BG, CH, CY , CZ, DE, DK, EE, ES, Fl, anee Notes on Codes andAbbreviations "appearing at the begin- FR, GB, GR, HU, TE, IS, IT, LT, LU, MC, NL, PL, PT, RO, no ofeach regular issue of the PCT Gazette SE, SI, SK, TR), OAPI (BF, BJ, CF, CG, Cl, CM, GA, GN, GQ, GW, ML, MR, NE, SN, TD , TG). Published: • - • with intemational search report CAN OPEN END OF CIL OPENING AND ITS PRODUCTION PROCESS FIELD OF THE INVENTION The present invention relates in general to containers and in particular to containers that have an open-easy end and that are designed to be opened by means of a mechanism of a pull tab. BACKGROUND OF THE INVENTION The term "open-easy end" is generally used for that class of container ends that are provided with an integrated mechanism that allows the consumer to open the container at the end to access the ingredients within the container, without require the use of a can opener or other external tool. A conventional open-easy end employs a pull tab having a pointed ear. The pull tab is edged to the end panel such that the ear rests adjacent to a weakened area along the periphery of the end panel. To open the pull tab it is rotated around the edging causing the ear to fracture the weakened area. Continuing to pull the tongue away from the end panel causes the rest of the weakened periphery to detach, allowing the entire end to open.

One type of open-easy end is its extensive use in the so-called open-easy end of "fully open" or "full opening", in which a peripheral mark, generally of circular configuration is formed in the extreme panel or adjacent to its periphery to allow its complete withdrawal. Total opening cans are distinguished from those easy open cans that when opened open have a comparatively small removable section and provide a comparatively small hole for product extraction. This last type of can end is more appropriate for packing products that are poured from the can such as beverages, beers or other liquids. On the other hand the cans of the full opening type are suitable for packing solid products such as sweets, nuts, meats or ground coffee. A generally recognized disadvantage of open-easy ends are the sharp edges that remain after the end of the can is opened and the consequent safety problems. U.S. Patent 4,511,299 to Zysset addresses those problems and introduces the concept of the use of the blunt protection backings formed by folding the end wall of the panel near the marking line. The formation method described in that Zysset patent, which was never successfully put into production, is shown in Figures 1 to 6. As seen in Figure 1 the starting material is a flat can end template 10. The end jig 10 is first subjected to a first forming operation to form a curve 15 and a portion of a side loop 18 on the peripheral edge of the end 10. As shown in Fig. 2, the end then undergoes a second folded operation stage and formed to create a pair of concentric notches 20, 22 defining internal and external shoulders 21, 23 extending below the second internal surface 14 of the end 10. A central rim 24 is also formed, which it extends above the level of the first outer surface 12 of the end 10. Referring now to Figure 3, the end 10 is subjected to another forming step in which the end portion 10 inside the flange 21 is rolled up, and the second flange 23 extends downward. After that, as shown in Figure 4, a mark 28 is formed in the central rim 24 and then the inner and outer rims 21, 23 are forced towards the inner surface 14 and the central ridge 23 is pushed towards the outer surface 12 until the inner and outer flanges 21, 23 abut the flange 24 to provide blunt protection flanges below the score line 28 (see Figure 5). The protective flanges formed by the inner and outer flanges 21, 23 of this double fold configuration extend in a common plane that is substantially parallel but spaced from the plane of the end 10. As shown in Figure 6, the complete end is product with a pull tab 34, the end of which extends adjacent the score line 28 to allow the end to be opened in a conventional manner. As can be seen in Figures 6 and 7. A completed end manufactured according to the method shown in Figures 1-5 includes the central flange 24 containing the marking line which is at the same level of the end 10 and resides essentially in the plane of the end 10, and the concentric recesses 30, 32 that surround the central rim. The recesses 30, 32 are formed by means of the specific bending technique described below with respect to the inner and outer flanges 21,23. While the cutting projection provided by the double-fold configurations such as those described in the Zysset patent is substantial, the sharp edge of an end panel that has been separated along a cut line may still present a threat of cuts. in the fingers for a consumer who unfortunately may have a contact with the edge from an unfavorable direction or orientation in which the blunt protection flanges of the double-fold flanges do not prevent substantially contacting the edge and the consumer's finger. There is a need for an open-easy end and a process to produce such an end, which improves the quality of the cut protection that is provided to the consumer. SUMMARY OF THE INVENTION Accordingly, it is an object of the invention to provide an improved open-easy end and a process for producing such an end that improves the quality of protection against cuts that is provided to the consumer. In order to obtain that and other objects of the invention, a method for producing an open-easy end for a container according to a first aspect of the invention, includes the steps of providing a can end having a peripheral edge and a panel, the panel having opposite sides first and second, the first side being adapted to point towards a container when the end is fixed thereto.; forming first and second notches in the panel separated from the peripheral edge, the notches extend below the level of the first side to form inner and outer flanges; forming a central ridge on the panel between the first and second notches, the central ridge extends above the level of the second side; forming a mark along the central flange on the second side of the panel; pushing the inner and outer flanges together and then towards the first surface while pushing the central flange towards the second surface, this step is carried out in such a way that the central flange deforms elastically in the marking; and fixing a pull tab on the end, the pull tab has the structure to separate the end along the mark. A method for forming a removable end by means of a pull tab according to a second aspect of the invention, includes the steps of providing a metal can end; forming inner and outer concentric flanges at the end that separates from the end, the inner flange extending is separated from the end by a greater distance than the outer flange; forming a notched mark between the internal and external flanges; pushing the inner and outer flanges together and towards the plane of the end until the flanges rest on the end and the end of the can is folded around the notched maca; and fixing a pull tab to the end, the pull tab has means for detaching the end along the mark. According to a third aspect of the invention, an open-easy end for a container includes an end panel having a mark defined therein, which defines a removable end panel portion; a first double fold defined adjacent and positioned radially inward from the mark, the second double fold below the mark defines a second edge of protection against the cuts projecting inwardly; the end panel elastically deforms in an area close to the mark to define a concave depression around the mark; and a pull tab fixed on the end panel. The preferred embodiments of the invention will now be described by way of example only, with reference to the drawings forming part thereof and to the appended descriptive text. BRIEF DESCRIPTION OF THE FIGURES Figures 1-6 are cross sections illustrating the steps in a prior art method to form an open-easy end; Figure 7 is a top plan view of the end construction according to the prior art; Figure 8 is a fragmentary cross-sectional view showing the tools for performing a first forming operation according to the preferred embodiment of the invention, shown in a first operating position. Figure 9 is a fragmentary cross-sectional view showing the tools shown in Figure 8, shown in a second operating position; Fig. 10 is a fragmentary cross-sectional view showing the tools for performing a second forming operation according to the preferred embodiment of the invention, shown in a first operating position; Figure 11 is a fragmentary cross-sectional view showing the tools shown in Figure 10, shown in a second operating position; Figures 12 (a) -12 (c) are fragmentary transverse images of a marking projection that is used in accordance with the preferred embodiment of the invention, shown in different wear states; Figure 13 is a fragmentary cross-sectional view showing the tools for performing a third training operation according to the preferred embodiment of the invention, shown in a small operational position; Fig. 14 is a fragmentary cross-sectional view showing the tools in Fig. 13, shown in a second operational position; Fig. 15 is a fragmentary cross-sectional view showing the tools for performing a fourth forming operation according to the preferred embodiment of the invention, shown in a first operational position; Fig. 16 is a fragmentary cross-sectional view showing the tools of Fig. 15 shown in a second operational position; and Figure 17 is a bounded micrograph showing a critical portion of an easy-open can that is constructed in accordance with a preferred embodiment of the invention. DESCRIPTION OF THE INVENTION Referring now to the drawings, in which the similar reference numbers designate the corresponding structure in all the views, and referring in particular to Figure 8, a tool assembly 42 for performing a first training operation in accordance with the preferred embodiment of the invention shown in an open pre-operational position with a metallic can end jig 40, which can be made of a material such as aluminum or steel. The tool assembly 42 includes a punch assembly 44 which includes an outer upper forming punch 48, an operational ridge forming punch 50 and a first operational bubble punch 52. The tool assembly 42 further includes a matrix assembly 46 having an external forming die 54, an elasticly supported mobile support die 56 and a first operational bubble forming die 58. As shown in Figure 8, the can end template 40 includes an end panel 60 having an first side 62 which is adapted to point inward of the container after the formation of the end of the can and a second opposite side 64 has been completed. Figure 9 shows the tool assembly 42 and the end template of the can 40 after completing the first training operation. As can be seen from Figs. 8- and 9, the interaction of the external upper forming punch 48 and the first operational ridge forming interaction 50 with an outer forming matrix 54 and the moving support matrix 56 forms a raised central ridge 66. and the start of the first and second notches 67.70 on each side of the raised central ridge 66. Simultaneously, the interaction of the bubble punch 52 with the first operational bubble formation matrix 58 forms the start of a bubble shape in the end panel 60 which is positioned radially inward of central rim 66 and notches 68, 70. The formation of this bubble shape has the effect of preventing material from entering the area of the central rim66 and the first and second notches 68, 70. After completing the first forming operation, the can end template will move to a second operational forming station containing second operating tools 70 shown in Fig. 10. The second operational tools 70 include a second outer operational forming punch 72, a second internal operational forming punch 74 and a second operational bubble forming punch 76. The second operational tools 70 further include an external forming matrix 78 movably mounted in a form-movable manner. elastic, a marking matrix 80 having a marking projection 81 extending upwards, which will be described in more detail in front and a second operational bubble formation matrix 84 which is positioned to cooperate with the second punch forming operational bubble 76. The second inner operational forming punch 74 is shaped to have annular extends downwardly 88 having a first annular recess 86 in an outer portion thereof and a second annular recess 90 in an inner portion thereof a projection. After completing the second forming operation as shown in Fig. 11, a mark will be defined on the central rim 66 of the end panel 60 and the first and second notches 68, 70 will be more discrete and better defined. The mark is defined on the second side 64 of the end panel 60. According to the preferred embodiment of the invention, the mark is indented, which means that for the purposes of this document the bottom of the mark is not flat but rather it has notches to induce bending, bending or bending of the end panel 60 in the area of the central flange 66 during the subsequent forming operations. Figure 12 (a) shows a marking projection 81 which is constructed in accordance with a preferred embodiment of the invention and which is beveled to a continuous edge 92 which will define a continuous indentation or notch in the bottom of the mark that is formed of that way. Preferably, this continuous edge 92 when the tool is new has a radius that is not greater than 0.00508 mm (0.0002 inches). Figure 12 (a) shows a vertical plane 94 that is perpendicular to a horizontal plane 96 in which the end plane 60 generally resides. The edge 92 is defined as the intersection of a first annular surface 98 that resides substantially within a plane which forms an angle a with respect to the horizontal plane 96 and a second surface 100. Preferably the angle a is in the range of about 17 degrees to about 23 degrees. The projection 81 is further defined by means of a third annular surface 102 that resides within a third plane having an angle with respect to the second surface 100 with an angle β which is preferably within a range of about 47 degrees to about 53 degrees. Figure 12 (a) shows the marking projection 81 after it has experienced a moderate amount of wear, while figure 12 (c) shows the marking projection 81 after an unacceptable amount of wear, while figure 12 (c) shows the marking projection 81 after an unacceptable amount of wear. As can be seen from these figures, the unique shape of the projection 81 ensures that it retains its notched profile during its useful life. Preferably, the continuous edge 92 when the tool is considered unacceptably worn has a radius that is not greater than 0.0127 mm (0.0005 inches). Figure 13 shows an assembly 104 that is used to perform a third forming operation in accordance with the preferred embodiments of the invention. The third operating tools 104 include a cam punch 106 that includes angled first and second angular cam surfaces 108, 110 and a third operational bubble punch 112. The third operational array tools include a grip matrix tool 114 that defines an annular recess 116 that is joined by means of an outer annular projection 118 and an internal annular projection 120. Also A third operational bubble formation array 121. is provided. Referring now to FIG. 14, as the third operation is performed, the shoulders defined in the end panel 60 that form the first and second notches 68, 70 are pushed forward. an downwards and to each other by means of the interaction with the cam surfaces 108 110 of the cam punch 106. As this occurs, the marked central ridge 66, which is restricted within the recess 116 by means of contact with the projections outer and inner rings 118, 120 of the gripper array 114, will begin to deform elastically when flexed or bent at a location of the mark 81 to form a recess annular concave on the second side 64 of the end panel 50 in the area of the central flange 66 which is adjacent the notched mark 81. This bending or bending effect creates important advantages in the cutting projections because it ensures that the sharp edges which are formed after the breaking of the mark 81 after opening the end of the can will have an angle in the direction of the cutting projection flange, as will be described in more detail below. The fourth forming operation shown in FIGS. 15 and 16 uses tools 120 for the operation including a compression punch 122, a fourth operational bubble formation punch 124 and a fourth operational grip matrix 126 having external annular projections and internal 128, 130 for restraining the central flange elastically deformed and marked 66 during this forming operation. The tools 120 further include a fourth operational bubble forming array 132. During the fourth forming operation the end panel part defining the central flange 66 and the first and second notches 68, 70 are further compressed forming a first double fold 134 which is defined adjacent and positioned radially inward of the mark 81 and a second double fold 136 which is defined adjacent and positioned radially outwardly of the mark 81. The first double fold 134 defines below the mark 81, a protective rim against cuts 138 extending projecting outwards, while the second double fold 136 defines below the mark 81 a second edge of protection against the cuts 140 projecting inwards. Figure 17 is based on a micrograph of the region adjacent to the mark 81 after completing the fourth forming operation. The concave recess 144 which is defined by bending or flexing the end panel 66 around the mark 81 is clearly shown. In this elastically deformed area, the portion of the end panel 66 that is immediately adjacent to the mark 81 lies within a plane. 146 that presents an angle with respect to the horizontal plane 96 in which the. Main body of the end panel 66, that angle F is preferably in the range of about 3 degrees to about 20 degrees, and more preferably within a range of about 8 degrees to about 18 degrees. By looking at figure 17 it can be easily visualized how after the breaking of the end panel 66 on the marking line 71 the sharp edges formed will be flexed inwardly towards the respective cut-off edges extending inwards and outwards. 140, 138. This reduces the consumer's exposure to sharp edges and increases the degree of security that is provided by the double-pleat cut protection 134, 136. The invention has been described above by way of example only and can be done in detail especially with regards to the way, the size and placement of the parts, without departing from the scope of the claims defined by the claims.

Claims (11)

1. NOVELTY OF THE INVENTION Having described the invention as above, the content of the following is claimed as property: CLAIMS 1. A method for producing an open-easy end for a container, characterized in that it consists of the steps of: a) providing an end of can having a peripheral edge and a panel, the panel has opposite sides first and second, the first side being adapted to point towards a container when the end is fixed thereto; b) forming first and second notches in the panel separated from the peripheral edge, the notches extend below the level of the first side to form inner and outer flanges; c) forming a central ridge on the panel between the first and second notches, the central ridge extends above the level of that second side; d) forming a mark along the central ridge on the second side of the panel; e) pushing the inner and outer flanges together and then towards the first surface while pushing the central flange towards the second surface, this step is carried out in such a way that the flange deforms elastically at that mark; and f) fixing the pull tab to the end, the pull tab has means for detaching the end along the mark. A method for producing an easy-open end for a container according to claim 1, characterized in that the step (e) is performed in such a way that the central rim will flex at that mark. 3. A method for producing an easy-open end for a container according to claim 2, characterized in that step (e) is performed in such a way that the central bead will flex concavely at that mark. . A method to produce an open-easy end for. A container according to any one of claims 1 to 3, characterized in that the step of forming a mark along the central ridge on the second side of the panel, consists in forming a mark having a notched bottom, thereby promotes the deformation of the central ridge on that mark during stage (e). A method for producing an easy open end for a container according to claim 4, characterized in that the notched bottom is thinned to form a continuous V-shaped recess. 6. A method for producing an easy open end for a container according to one of claims 1 to 5, characterized in that step (b) is performed by forming first and second concentric notches in the panel separated from the peripheral edge. A method according to any of claims 1 to 6, characterized in that step (b) consists of forming inner and outer concentric flanges at the end, which move away from that end, the inner flange moves away from that end a distance greater than the outer flange. 8. An easy open end for a container, characterized in that it has: an end panel having a defined mark on which a removable portion of the end panel is defined; a first double fold defined adjacent to and radially inwardly of the mark, the first double fold defines below that mark a first cut protection flange extending outwardly projecting; a second double fold defined adjacent to and radially outwardly of the mark, the second double fold defines below that mark a second edge of cut protection that extends projecting inwardly; the end panel is elastically deformed in an area near the mark to define a concave depression around the mark; and a pull tab attached to that end panel. 9. An easy-open end for a container according to claim 8, characterized in that the mark is indented to define a mark bottom that is thinned to form a continuous recess in the form of a V. 10. One end opens easy for a container according to claim 8, characterized in that the recess is shaped to have an edge radius that is not greater than 0.0127 mm. 11. An easy-open end for a container according to claim 10, characterized in that the concave depression extends over the entire length of the mark.