METHOD AND APPARATUS FOR REFORMING THE EDGE OF AN UNCUTED PIECE FOR AN END CLOSURE OF
CONTAINER
Field of the Invention The present invention relates to a process for reforming the edge of a cover that opens a container, and in particular, to a method and apparatus for reforming the edge of a two or three piece hull before the helmet is fired to the body of the container to net the festoon or other irregularities in the perimeter of the helmet. BACKGROUND OF THE INVENTION In the process of manufacturing and filling a two or three-piece beverage or food container, a number of processes are used to close or cover an opening of a container. Typically, the body of a container has a side wall which is substantially cylindrical with at least one substantially circular ring defining an open end of the body of the container. In a number of previous configurations, a hull at the end of the container which has substantially the disc shape (although it may have several recesses, marks, indicia and the like) has a perimeter substantially the same shape as the aperture ring. of the container. The container can be closed by firing the angular region of the perimeter of the hull to the region of the rim of the body of the container, as is known to those skilled in the art by a double-bake operation. In many situations, it is greatly preferred to maintain, in any circumferential position along the perimeter of the hoof of the hoop of the container body, a sufficient radial extent of the part of the annular hull to be fired, in proximity to the hoop part. of the can body to which it will be fired to ensure that the stew has a structural integrity, forms a preferably watertight seal between the hull and the body of the container and has the ability to withstand certain knocks or impacts such as those encountered with Frequency during transport, retail sale, sale and normal use of the end user. A number of procedures frequently involved in the proportion and formation of the helmet, result in a helmet whose perimeter falls out of perfect regularity (normally it leaves a perfect circle), as in the cases where the parts of the periphery of the Helmets are a bit jagged or scalloped, compared to a perfect circular shape. These outputs from the periphery of the helmet of the ideal regularity, contribute to configurations of the container in which the amount of material provided to achieve the cooking operations exceed the materials, which at least theoretically, are required as a minimum. For example, when an annular region with a radial extension of X is needed to achieve the desired cooking integrity, if the rim of the hull is scalloped inward by a radial extension to Y, the hull must be supplied with a cooked region. annular having a radial or intended extension of approximately X + Y, (so that, even in parts of the annular region where the scallop occurs, the radial extension will be at least equal to the nominal or intended extension of X + Y, minus the maximum scalloped defect of Y, to provide a guaranteed minimum radial extension of X, as desired). For this reason, part of the operations of training and / or cooking of the helmet, provide a double seam which is larger than could be theoretically required in a minimal way, in order to maintain the integrity of the seam even in the cover of a scalloped amount of the rim of the helmet. Accordingly, it would be useful to provide a method that can reduce or eliminate the adverse effects of festooning on seam sizes, to provide containers with integral sturdy seams but with a small seam size. In many container forming processes, it is desirable to provide seam regions (or other regions) of the container closure closure hull, with a degree of hardness, for example, to help maintain the integrity of the seam, regardless of normal bumps or impacts on the container. To provide a suitable seam, the helmet should normally have a diameter adapted to the diameter of the rim of the container body, but which also has a sufficient thickness to provide and maintain a reliable seam. Accordingly, it would be convenient to provide a helmet that provides regions that are at least hardened, particularly in the annular seam area. It would be desirable to provide a helmet forming process that results in at least some increase in the effective diameter of the hull, without regions of thinning of the hull to the point where structural integrity can be compromised. SUMMARY OF THE INVENTION The present invention comprises subjecting the helmet or the piece before cutting the helmet to the application of a forming operation such as wedging, patination or die forming at least at the periphery or in the seam area of the helmet prior to the sewing operation. Preferably, if wedging is used, the wedging operation comprises the use of a die having a wall which can define the desired, (usually, regular) shape of the periphery of the helmet, so that the wedging can reform a helmet which has a shape that may be scalloped or have irregular edges otherwise, to a shape having substantially no scalloped and substantially regular edges. Preferably, the present invention allows the formation of containers having a seam size smaller than the seam size provided in correspondingly formed containers formed through previous processes, without substantially sacrificing the integrity or durability of the seam. The wedging operation preferably provides an increase in the diameter of the hull (in at least some parts around the circumference) having all relatively minor effects on the thickness of the wedge region. Preferably, the wedging achieves a degree of hardening of operation of the wedge area, which may help to compensate for the effects of any decrease in thickness caused by the wedging operation. In one embodiment, a non-beaded or non-beaded hull is transferred to a reforming station. This station contains a wedging punch and a wedge punch. The coining die has machined on the face of the die the desired diameter of the piece without cutting round finished. The die cavity has a round die wall which stops the external flow of the material during the wedging process. The die wall produces the final shape of the piece without cutting. During the wedging process, the wedging punch compresses the edge of the piece without scalloping the hull not flanged or not previously flanged. The wedging of the wedged area causes the material to flow out until it is in contact with the die wall, forming the external diameter of the uncut piece. This corrects the scalloped edge of the uncut discs and additionally hardens the edge operation and increases the diameter of the uncut piece. This configuration can also eliminate the (expensive) need for non-round cutting edge tools.
BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a top plan view of an unreformed helmet placed in a wedging die according to an embodiment of the present invention; Figure 2 is a cross-sectional view of the helmet and the die taken along line 2-2 of Figure 1, which also shows a wedge punch according to an embodiment of the present invention; Figure 3 is an expanded detail of region 3 of Figure 2; Figure 4 is a top plan view corresponding to the view of Figure 1 although once the wedging operation has been carried out. Figure 5 is a cross-sectional view taken along line 5-5 of Figure 4; Fig. 6 is an expanded detail view of region 6 of Fig. 5; Figure 7 is a flow chart showing the steps selected in a helmet stitching and forming operation according to previous procedures; and Fig. 8 is a flow chart showing the selected steps of a helmet stitching and forming process, including cocking according to the embodiments of the present invention. Detailed Description of the Invention In normal situations, a hull at the end of the container 112 is formed of a metal, such as an aluminum alloy. As illustrated in FIG. 2, the container end shell 112, although with a strictly circular shape, can be pulled out of the strict circularity, such as having one or more regions serrated or festooned inwardly 114a, b, c, d that define earring openings. The outlets of the regularity may arise in a number of ways, including imperfections in the cut or original stamping of the uncut or flat piece in the form of a disc, forming procedures such as stamping and other procedures to form the annular recess 116 and / or the elevated periphery 118 of the hull, and may have contributions from the metallurgy of the hull and / or imperfections in the concentricity of the tooling. In any case, it is common for a helmet, such as the one illustrated in Figures 1 and 2, to have at least one and often a plurality of scallops or earring openings 114a-d. The radial extension 312 (Figure 3) of the opening will normally vary as shown, along the circumference of the hull. In a typical hull designed to be used in the formation of a typical 12-ounce beverage container, opening 312 is usually not greater than about 0.0127 centimeters (0.0050 inches), although there may be a substantial variation in this value. The resulting variations in the weight of the non-flanged edge lead to a double seam size which is greater than desired, thereby increasing the material cost of the container. According to one embodiment, the helmet 112 can be reformed by wedging part or preferably all the peripheral areas of the helmet. As best seen in Figures 2 and 3, in one embodiment the helmet 112 is placed on or within the cavity 121 of the die 122. The die 122 has an annular surface 124 for receiving and supporting at least the annular periphery of the helmet 112. Adjacent to the outer edge of the support 124, there is a vertical wall region 126 of the die. The wall 126 defines the shape (such as circular) and desired diameters of the helmet. As illustrated in Figures 2, 3, 5 and 6, a punch 212 is configured to cooperate with the die 122, to perform wedging as will be described more fully below. The punch 212 includes an outer cylindrical wall 214 with a shape and diameter that coincide (preferably with a close tolerance) with the shape and diameter of the wall of the die 126. The wedging surface defines a generally annular planar region 216 that extends radially inward at a distance 612 (Figure 6). In practice, a helmet 112 is placed in the cavity of the die 122, as illustrated in Figures 1 and 2. The punch 212 is brought down 218 with sufficient force to achieve wedging as will be described later. In the maximum downward stroke of the punch 212, as illustrated in Figures 5 and 6, the punch 212 causes a plastic deformation of the metallic peripheral region of the hull. The wedging process causes the minted area 412 (Figure 4) to be reduced 616 in thickness, compared to the thickness 314 of the area before wedging. The wedging also results in a hull material that is displaced in the scalloped or apertured regions 114a, b, c, d so that the wedging material generally flows in a radially outer net direction until it meets the wall of the cap. die 126, as illustrated in FIG. 6, thereby achieving a periphery of the hull having a regularity (and diameter) of the die wall 126. In general, the reduction in total of the volumes (the reduction in thickness ) 616 of the area of the minted region 412, will not be substantially greater than the total volume of the wedged regions or scalloped openings 114a, b, c, d. Therefore, it is anticipated that in most situations the wedging will provide a reduction in thickness 616 of the peripheral region of the hull, which will be small enough so as not to severely affect the strength or integrity of the hull. However, for the existing extension to have otherwise, some reduction in strength or integrity, there is a compensating factor for an increase in hardness that results in the hardening effect of the wedging process in the minted area. 412
As shown in Figure 7, the prior procedures normally involved, receive a flat uncut piece 712 which forms 716 an annular recess 116 or which otherwise forms the uncut piece. As described above, in prior procedures the hull was flanged and sewn to frequently attach the can body 722, after a pre-beading operation 720. As illustrated in Fig. 8, the present invention preferably adds a wedging process to achieve the reform of the edge 818 before the beading step 722 (and preferably before a pre-beaded end 720), and in the illustrated embodiment, after other forming steps such as the formation of the annular recess 716. In By virtue of the above description, a number of advantages of the present invention can be observed. The present invention reduces or eliminates the effects of non-regularity or scalloping of the edges of the uncut piece or helmet. Containers with smaller seam sizes can be achieved without compromising seam integrity or durability. The sewing areas that are provided have been hardened by means of an operation and the increase that originates in the diameter forms the wedging operation which results in material savings. A number of variations and modifications of the present invention may be used. It is possible to use some features of it without using others. For example, it is possible to use the present invention to provide a hardening by means of an operation of the peripheral area of the helmet, without completely eliminating the earring openings in a necessary manner. Although the present invention has been illustrated with examples of helmets with ideally circular peripheries, the present invention could be used for helmets (and containers) without a circular shape, such as ellipses, ovals, polygonal cross sections and the like. Although an example of a radial extension 612 of a wedging area has been provided, the present invention can be used with larger or smaller wedging areas. Although the present invention has been illustrated by examples in which the wedging operation is carried out as a separate operation, it is possible to design processes in which the wedging operation, as described in the present invention, is carried out in accordance with the invention. performed concurrently with one or more operations such as a streak operation, a recess or rib formation operation, and the like. Although the illustrated embodiment provides an annular wedging area resting on a plane substantially parallel to the plane of the region of the larger hull armor, the wedging area can be oriented differently. Although in the illustrated embodiment, the inner wall 222 of the punch has a conical shape (to aid punch removal) while the outer wall 214 is cylindrical, it is possible to provide a bevel or angle (preferably light) for the outer wall (preferably with an angle corresponding to the wall of the die) to assist in the extraction of the punch and / or guide or alignment. Although the illustrated embodiments provide a punching surface 216 substantially substantially parallel to the plane of the hull, it is possible to supply the bottom surface of the punch (and therefore the resulting wedging area) with an internal or external bezel (preferably lightweight). ). Although the present invention has included the description of a wedging in the form of a forming operation, other forming operations can also be used and irregularities in the periphery of the uncut piece can be reduced or eliminated to allow, for example, smaller seams. Examples of other training operations include patination or die forming. Those skilled in the art will understand how to use patination or die forming to reduce or eliminate irregularities, after understanding the present description. The present invention includes in several embodiments components, methods, processes, systems and / or apparatuses substantially as described and illustrated therein, including various embodiments, sub-combinations and sub-groups thereof. Those skilled in the art will understand how to make and use the present invention after understanding the present disclosure. The present invention, in various embodiments, includes providing apparatus and processes in the absence of articles not illustrated and / or written in the present invention or in various embodiments thereof, including the absence of such items, how they may have been used in previous devices or processes, to improve, for example, the performance, facilitate and / or achieve the reduction of implementation cost. The above description of the present invention has been presented for the purpose of illustration and description. The foregoing is not intended to limit the present invention to the form or forms described herein. Although the description of the present invention has included the description of one or more modalities and certain variations and modifications, other variations and modifications are within the scope thereof, for example, as those which may be within the skill and knowledge of the skilled in the art, after understanding the present description. It is intended to obtain rights that include alternative modalities up to the allowed point, including structures, functions, ranges or alternative, interchangeable or equivalent steps to those claimed, whether such structures, functions, ranges or alternative, interchangeable and / or equivalent steps have been here described or not, and without pretending to dedicate publicity to any subject matter patented.