MXPA98002548A - Systems and methods for manufacturing decorative metallic cans - Google Patents

Abstract

The present invention relates to a method for manufacturing a metal can body that is distinctly configured for the purpose of improving its visual presentation to consumers, which comprises the steps of: (a) manufacturing a can body preform; c) providing a mold unit having at least one mold wall defining a mold cavity conforming to the desired final shape of the can body; (d) placing the can body preform into the mold cavity. mold; and (e) supplying a pressurized fluid inside the mold cavity, such that the preform of the can body is forced by the pressure against the mold wall, causing the preform of the can body to assume the desired final shape of the can body, and characterized by the passage of (b) at least partially temper the entire preform of the can body, thereby giving the body preform of the hardened can greater ductilid

Description

SYSTEMS AND METHODS FOR MANUFACTURING METALLIC DECORATIVE DECORATIVE CANS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to the field of consumer packaging, and more specifically to metal cans, such as steel and aluminum cans that are commonly used to pack soft drinks, other beverages, food, and aerosol products. 2. Description of the Prior Art and Recent Technology Metal cans for soft drinks, other beverages, and other materials, of course, are widely used in North America and throughout the world. The assignee of this invention, Crown Cork & Seal Company of Philadelphia, is the world's largest designer and manufacturer of these cans. The technique of manufacturing and packing metal cans is constantly evolving in response to the best technology, new materials, and the best manufacturing techniques. Other forces that drive the evolution of technology in this area include the prices of the raw material, the nature of the new material that is going to pack, and the marketing goals of the large companies that manufacture and distribute products for the consumer, such as soft drinks. There has been interest for some time for a metal container that is configured differently from the conventional cylindrical can, in such a distinctive way that it becomes part of the commercial aspect of the product, or that indicates otherwise the source or nature of the product. However, to the best knowledge of the inventors, no one has yet developed a practical technique to manufacture said can of irregular shape in the volume and speed that would be required to actually introduce this product to the market. U.S. Patent No. 3,224,239 to Hansson, dating from the mid-1960s, discloses a system and process for using pneumatic pressure to reconfigure cans. This process used a piston to force compressed air into a can, which was placed inside a mold. The compressed air caused the wall of the can to flow plastically until it assumed the shape of the mold. Technology such as the one disclosed in the Hansson patent, for the knowledge of the inventors, has never been used successfully for the reconfiguration of stretched cans and ironed wall. One reason for this is that the stress that develops in the wall of the can as it is being deformed can lead to defects that are potentially fault inducing, for example, localized thinning, cracking, or cracking. The risk of thinning can be reduced by increasing the thickness of the can wall, but this would make the shaped cans thus produced prohibitively expensive. The risks of cracking and cracking can be reduced by a process such as tempering, but at the cost of a reduction in the robustness and resistance to abuse of the final product. There is a need for an improved apparatus and process for manufacturing a configured metal can design that is effective, efficient, and economical, especially when compared to the technology that has been developed up to now for these purposes, and which reduces the tendency of a can configured to fail as a result of thinning, cracking, or cracking.

SUMMARY OF THE INVENTION In accordance with the foregoing, it is an object of the invention to provide an improved apparatus and process for the manufacture of a shaped metal can, which is effective, efficient, and economical, especially when compared to the technology that has been developed up to now for these purposes, and that provides a security against the internal tensions inside the can, which could cause thinning, cracking, or cracking.

In order to achieve the above and other objects of the invention, a method for manufacturing a metal can body that is distinctively configured for the purpose of improving its visual presentation to consumers includes, in accordance with a first aspect of the invention, the steps of: (a) providing a can body preform; (b) providing a mold unit having at least one mold wall defining a mold cavity that conforms to a desired final shape of the can body, the mold unit being constructed of more than one part, being able to move when less one of the parts toward each other in a direction that is substantially parallel to an axis of the preform of the can body during operation, the mold wall including inwardly extending and outwardly extending portions; (c) placing the preform of the can body inside the mold cavity, to previously compress the preform of the can body, with the portions extending inwardly of the mold wall; (d) supply a pressurized fluid inside the mold cavity, so that the preform of the can body is pressed against the wall of the mold, making the preform of the body of the can assume the desired final shape of the can body, minimizing the previous compression that the amount of outward deformation required to reach the final shape of the can body is realized in step (c); and (e) in a substantially simultaneous manner with step (d), moving at least one of the mold parts toward each other in the axial direction. According to a second aspect of the invention, a method for manufacturing a metal can body that is distinctly configured for the purpose of improving its visual presentation to consumers, includes the steps of: (a) manufacturing a can body preform; (b) at least partially annealing at least a portion of the preform of the can body, thereby giving the hardened portion of the can body preform greater ductility; (c) providing a mold unit having at least one mold wall defining a mold cavity conforming to a desired final shape of the can body, the mold unit being constructed of more than one part, being able to move when less one of the parts towards the other in a direction that is substantially parallel to an axis of the preform of the body of the can during the operation; (d) placing the preform of the can body inside the mold cavity; (e) supplying a pressurized fluid inside the mold cavity, such that the preform of the can body is forced by pressing against the mold wall, causing the preform of the can body to assume the final desired shape of the mold. body of the can; and (f) in a substantially simultaneous manner with the step (e), moving at least one of the mold parts towards the other in the axial direction. According to a third aspect of the invention, an apparatus for manufacturing a metal can body that is distinctly configured for the purpose of improving its visual presentation to consumers includes a structure for manufacturing a can body preform; molding the structure comprising a mold unit having at least one mold wall defining a mold cavity conforming to a desired final shape of the can body, this mold wall comprising inwardly extending portions and portions thereof. which extend outwardly, the mold unit being constructed of more than one part, at least one of the parts being movable towards the other in a direction that is substantially parallel to an axis of the can body preform during the operation; a structure of positioning for positioning the preform of the can body inside the mold cavity, for previously compressing the can body preform by the portions extending inward from the mold wall; a fluid supply structure for supplying a pressurized fluid inside the mold cavity such that the preform of the can body is forced by pressing against the mold wall, causing the preform of the can body to assume the shape desired end of the can body, minimizing the previous compression the amount of outward deformation that is required to achieve the final shape of the can body; and an axial reduction structure for moving at least one of the mold parts towards the other in the axial direction. According to a fourth aspect of the invention, an apparatus for manufacturing a metal can body that is distinctly configured for the purpose of improving its visual presentation to consumers, includes a structure for manufacturing a can body preform; a structure for at least partially tightening at least a portion of the preform of the can body, thereby giving the hardened portion of the can body preform greater ductility; a mold structure comprising a mold unit having at least one mold wall defining a mold cavity that is The shape of the mold unit is formed by more than one part, it being possible for at least one of the parts to move towards the other in a direction that is substantially parallel to an axis of the body preform. the can during the operation; a positioning structure for positioning the can body preform inside the mold cavity a fluid supply structure for supplying a pressurized fluid inside the mold cavity, such that the preform of the can body is forced by pressing against the wall of the mold, making the preform of the body of the can assume the desired final shape of the body of the can; and an axial reduction structure for moving at least one of the mold parts towards the other in the axial direction. These and other different advantages and features of novelty characterizing the invention are pointed out with particularity in the appended claims hereto, and which form a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings forming an additional part of the present, and to the accompanying descriptive matter, wherein it is illustrated and a preferred embodiment of the invention is described.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view taken through a can body preform, or a preform that is constructed in accordance with a preferred embodiment of the invention. Figure 2 is a side elevational view of a can body configured in accordance with a preferred embodiment of the invention. Figure 3 is a diagrammatic view of an apparatus for manufacturing a can body configured in accordance with a preferred embodiment of the invention. Figure 4 is a fragmentary cross-sectional view through a mold unit in the apparatus illustrated in Figure 3, shown in a first condition. Figure 5 is a fragmentary cross-sectional view through a mold unit in the apparatus illustrated in Figure 3, shown in a second condition.

Figure 6 is a schematic diagram illustrating a pressure supply apparatus for the mold unit illustrated in Figure 3. Figure 7 is a diagrammatic illustration of a precompression step that is performed in the apparatus illustrated in Figure 3 Figure 8 is a diagrammatic illustration of a step of enhancement in a method that is performed in accordance with a second embodiment of the invention. Figure 9 is a diagrammatic illustration of a centrifugation step in a method that is carried out in accordance with a second embodiment of the invention. Figure 10 is a diagrammatic illustration of a twisting step that can be performed as a second step in any of the second or third embodiments of the invention referred to above.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, in which like reference numerals designate the corresponding structure throughout all the views, and referring in particular to Figures 1 and 2, a can body preform According to a preferred embodiment of the invention, it is the body of a two-piece can, which is preferably formed by the well-known stretching and pressing process. The preform of the can body 10 includes a substantially cylindrical side wall surface 12, a bottom 14, and an upper neck portion 16. Alternatively, the upper portion of the cylindrical side wall 12 could be straight. As is well known in this area of technology, the preform of the can body 10 must be washed after the Stretch and ironing process, and then it should be dried before being sent to the decorator. The drying process is typically performed at a temperature of approximately 250 degrees Fahrenheit (which is approximately 121 degrees Celsius). In accordance with an aspect of this invention, the drying is carried out at a higher temperature than the ordinary one, to partially temper at least the selected portions of the preform of the can body 10. In FIG. 1, a heat source 18 is schematically illustrated, which is preferably part of the dryer assembly, but could be at any point of the appliance before the molding unit. As will be discussed in more detail below, the preform of the can body 10 is preferably formed of aluminum, and the partial tempering preferably is performed at a temperature that is substantially within the range of approximately 375 degrees Fahrenheit (approximately 190.5 degrees. Celsius) at approximately 550 degrees Fahrenheit (approximately 288 degrees Celsius), with a more preferred scale being approximately 450 degrees Fahrenheit (approximately 232 degrees Celsius) at approximately 500 degrees Fahrenheit. { about 260 degrees Celsius), and a more preferred temperature being about 475 degrees Fahrenheit (about 246 degrees Celsius). This contrasts with the true tempering, which would be a temperatures greater than 650 degrees Fahrenheit (approximately 353 degrees Celsius). The purpose of partial tempering is to give the can body preform 10 sufficient ductility to form in a shaped can 20, as shown in Figure 2 of the drawings, but a greater robustness than would be possible if it were fully tempered the preform of the can body. Alternatively, partial tempering could be done in an oven, such as the lacquer or decorator oven, instead of the dryer. Alternatively, the preform of the can body 10 could be made of steel instead of aluminum. In this case, the preferred temperature scale for partial tempering would be substantially within the range of 1,112 degrees Fahrenheit (600 degrees Celsius) to approximately 1,472 degrees Fahrenheit (800 degrees Celsius). More preferably, partial tempering would be performed at approximately 1,382 degrees Fahrenheit (750 degrees Celsius). Referring now to Figure 2, the configured can 20 is decoratively and distinctly configured, in order to improve its visual presentation for consumers. As can be seen in Figure 2, the can body 20 includes a bottom 26, a shaped side wall 22 that is configured to deviate substantially of the conventional cylindrical can body shape, such as the shape of the can body preform 10. The shaped side wall 22 includes areas, such as ribs 30 to grooves 32, where it might be desired to accentuate these deviations from the cylindrical. In accordance with an important aspect of the invention, the decoration is provided on the external surface of the configured side wall 22, in a manner that accentuates the areas of the side wall where it is desired to accentuate the deviation from the cylindrical shape. As can be seen in Figure 2, a first type of decoration, which may be a lighter color, is provided on the rib 30, while a second decorating time 36 is provided, which may be a darker color, inside at least one of the grooves 32. By providing this selective decoration, and by properly registering the decoration with the deviations of the configured side wall 22, a synergistic visual effect can be obtained that would be impossible to obtain only by the can configuration or by decorating the can. Referring again to Figure 2, the configured side wall 22 also has a flat area 28, where writing or a label could be applied, and is closed by a can end 24, which is applied in the Traditional double welding process. According to the preferred method, after partial tempering by the heat source 18 in the drying station, the preform of the can body 10 will be transported to a decorator, where the distinctive decoration will be applied while the can body preform 10 is still in its cylindrical configuration. Markers could also be applied during the decorating process, which can be used to register the decoration to the contours of the mold during the subsequent training steps, which will be described in more detail below. Referring now to Figure 3, an apparatus 38 is illustrated which, in accordance with the preferred embodiment of the invention, is provided for manufacturing a shaped can 20 of the type illustrated in Figure 2. As can be seen in Figures 3, 4, and 5, the apparatus 38 includes a mold 40 having a mold wall 46 that defines a mold cavity 42 that conforms to the desired final shape of the shaped can body 20. As shown diagrammatically in FIG. Figure 7, the mold 40 is of the split-wall type, and the mold wall 46 will include inwardly extending portions 48 that are smaller in diameter than the diameter Db of the cylindrical side wall 12 of the can body preform 10 illustrated by the dotted lines in Figure 7b. The wall of the mold 46 will also include a number of outwardly extending portions, which are of a diameter greater than the diameter Db of the side wall 12 of the can body preform 10. In other words, the portions that extend inward 48 tend to compress the cylindrical side wall 12 of the can body preform 10 to the position 12 'shown by the solid lines in Figure 7b, while the side wall 12 of the can body 10 preform, must expand to conform to the outwardly extending portions 50 of the mold wall 46. Preferably, the perimeter of the cylindrical side wall remains of a constant length when compressed in this manner, such that the perimeter of the cylindrical lateral wall 12 'is of the same length as the circumference of side wall 12 of the preform of can body 10. As best shown in Figure 3, mold unit 40 has three die parts 82, 46, and 84, comprising the neck ring, the side wall of the mold, and the base support, respectively. The die parts are separated from one another by holes or "broken lines" 86 and 88. For ease of machining, the die of the base support 84 is made in two parts, supporting a central part 90 to the dome of the base of the body of the can The neck ring 82 provides a simple support to the neck portion of the body of the can. These components together define the chamber or mold cavity 42, to receive the body from the can, and are machined to the final desired shape of the can body after blow-forming. Ventilation holes 49 are provided (see Figures 4 and 5), to allow trapped air to escape during formation. A pair of seal and support rings 92, 94, and a rubber sealing ring 96, are provided to seal the upper edge of the container body. A space-saving mandrel 98 passes through the center of the seal and support rings 92, 94, 96, to a position just above the support dome of the base 84. The mandrel 98 supplies air to the cavity of a body can, inside the cavity 42, by means of a central hole 100 and the radial passages 102. The apparatus further includes a top piston and a bottom piston 104, 106, which together apply a load to both ends of the can in the mold cavity 42. The lower piston 106 can be moved upwardly by the structure of a pressurized air supply that is fed into the piston by passage 108. In a similar manner, the upper piston can be moved downwardly by the structure of a pressurized air supply that is fed to the piston by means of passages 110 and 112. In the preferred embodiment shown, passage 110 connects with center hole 100 of mandrel 98, such that the upper piston and the can cavity share a common air supply. The common air supply is divided for the piston 104 and the cavity at the junction of the air passage 112 and the hole of the central mandrel 100, inside the piston 104, to minimize the losses, and to maintain the same pressure supplied to the cavity. and the piston. Preferably, elements are provided to control the flow velocity of the air supplied to each piston and the cavity. Accordingly, the pressure of the cavity and the pressure of the piston can be tightly controlled. A schematic circuit diagram showing the manner in which the air is supplied to the pistons and the can cavity is shown in Figure 6. In Figuré, the upper piston 104 and the seal and support rings 92, 94 are shown schematically as a single unit 114. In the same way, the base support 84, 90 and the lower piston 106, are shown as one unit 116. Units 114 and 116, and neck ring 82, can be moved, while the die of sidewall 46 of the mold is shown fixed. The circuit comprises two pressure supplies.

The pressure supply 118 supplies pressurized air to the upper piston 104 and the can cavity inside the mold cavity 42. The pressure supply 120 supplies pressurized air to the lower piston 106 only. The two supplies each comprise pressure regulators 122, 124, reservoirs 126, 128, vent valves 130, 132, and exhaust valves 134, 136. In addition, the lower pressure supply 120 includes a flow regulator 138. Optionally, the upper pressure supply 118 may also include a flow regulator, although it is not considered essential to be able to adjust the flow in both supplies. The tanks 126, 128 prevent a high drop in the supply pressure during the process. Typically, high pressure air of about 30 bar is introduced into the cavity of the can, and to drive the top of the can. The air pressure to drive the lower piston 106 is typically around 50 bar, depending on the area of the piston. The air pressure inside the mold cavity 42 provides the force required to expand the can body preform outwards, but also applies an undesired force to the neck and the base of the can, which leads to the longitudinal tension on the side wall of the can. From In this way, the two pistons are used to drive the upper part and the lower part of the can, providing a force that counteracts this tension in the side wall of the can. The air pressure supplied to the pistons is critical to avoid a failure of the can during formation, due to cracks or wrinkling. The cracks will occur without the tension of the side wall of the can not be sufficiently counteracted by the pressure of the piston, since the pressure in the pistons is too low. Conversely, the pressure of the supplied air should not be so high, since this will lead to the formation of corrugations in the side wall. For this reason, stops are preferably not required to limit the stroke of the pistons. If the stroke were limited, the can could not expand completely against the mold wall before the pistons reached the stops. If this occurs, the tension in the side wall of the can would not be balanced by the pressure of the piston, with a consequent risk of cracking. In effect, the contact of the expanded can with the side wall of the mold prevents further movement of the pistons. Therefore, it should be noted that the balance between the pressure of the can cavity and the piston pressure is preferably maintained at all times of the entire formation cycle, so that the pressure rise index in the cavity and behind the pistons must be balanced throughout the cycle, particularly when rendering the wall of the can. The pressure rise index can be controlled by the flow regulator 138, or by adjusting the supply pressure by means of pressure regulators 122, 124. By adjusting the pressure of the can cavity against the Pressure applied to move the mold elements 82, 46, 84 towards each other, the apparatus can be operated in one of three different ways. By minimizing the application of pressure to the external mold parts 82, 84, the apparatus can be operated to simply move the mold parts toward each other, without exerting force on the can body. This will reduce the gaps 86, 88 in the mold unit 40, since the can body shrinks longitudinally during the expansion process, and will reduce, but not necessarily neutralize, the axial tensile stress created in the side wall of the body. of the can during the expansion. Alternatively, by providing greater pressure to urge the outer parts of the mold toward each other, a slight longitudinal or axial force is applied to the body of the can, which is substantially equal to the tension by axial traction in the side wall of the can body, thereby balancing the tension, and protecting the body from the can of a consequential weakening and a possible cracking. A third way of. operation would be to provide an even greater pressure to drive the external parts of the mold toward each other, in order to apply an axially compressive force to the body of the can, which is greater than would be necessary to cancel the tensile stress in the lateral wall during the operation. It is believed that a net compression force is preferable, since this force does not lead to wrinkling. In order to form the can, ventilation valves 130, 132 are first opened. It is possible to have a short delay between the opening times of the vent valves, if required, to obtain a better coupling between the piston pressures and of the cavity, but then there will be a need for a higher rate of pressure rise for a circuit, in order to maintain this balance. A delay can also be used to compensate for different tube lengths, maintaining a pressure balance at the time of formation. The upper supply 118 is divided for the piston 104 and the cavity, as close as possible to the piston 104, as described above with reference to Figure 3. The apparatus is designed in such a way that, at the end, when each piston reaches its maximum stroke, the can is completely reconfigured, and the recesses 86, 88 do not close at the end. The closing of the holes can lead to a crack of the can, due to the excessive tension in the side wall, in the same way as the limiting movement of the pistons does before a full expansion has occurred. However, the final gap should not be excessive, as any witness marks on the side wall become too apparent, although the removal of the sharp edges on the division lines alleviates this problem. Once the configuration operation is completed, the air is extracted by means of valves 134 and 136. Clearly, the extraction valves are closed through the entire actual formation process. It is important that both supplies are ventilated simultaneously, since the compression force applied by the pistons to balance the pressure of the cavity (longitudinal tension) may be greater than the axial resistance of the can, so that irregular extraction leads to collapse From the can.

As best seen in Figure 4, the preform of the can body 10 is preferably placed inside the mold cavity 42, and its internal space is sealed in communication with a source of pressurized fluid, as described above. As can be seen in Figure 4, the cavity 42 is designed to impart a slight compression to the preform of the can body 10 as it is inserted therein. This is preferably done by forming the mold assembly elements in the halves 52, 54, shown in Figure 4, which are divided so that they can be closed around the preform of the can body, before the pneumatic expansion of the mold. the preform of the can body 10. As the mold halves 52, 54 are closed around the cylindrical side wall 12, the inwardly extending portions 48 of the mold wall 46, thereby compress, or previously compressed, cylindrical sidewall 12 by distances up to the amount Rendered 'shown in Figure 7. After the mold has been closed and sealed, and pressurized fluid is supplied into the mold cavity 46, to force the preform of the can body 10 against the mold wall. 46, the preform of the can body 10 will be forced to assume the desired final shape of the shaped can 20. The state of the configured side wall 22 is shown after the passage of Figure 5. In this step, the cylindrical side wall 12 of the can body 10 preform expands to a quantity Rsai da, again shown diagrammatically in Figure 7. Preferably, the pre-compression that is effected by closing the mold halves 52, 54 is performed to deflect the side wall 12 of the can body preform 10 radially inward by a distance Rendered 'that is within the range of approximately 0.1, to approximately 1.5 millimeters. More preferably, this Rendered distance is within the range of 0.5 to about 0.75 millimeters. The Rsaida distance by which the cylindrical side wall 12 radially expands outwards to form the outermost portions of the shaped side wall 22, preferably is within the range of about 0.1 to about 5.0 millimeters. A more preferable scale for the Raaiida distance is approximately 0.5 to 3.0 millimeters. More preferably, Rsalide is about 2 millimeters. In order to understand the benefit obtained by pre-compression of the cylindrical side wall 12 before the expansion step, it should be understood that a certain amount of quenching or partial quenching may be useful, particularly in the case of aluminum can bodies. , to obtain the necessary ductility for the expansion step. However, the more complete the tempering, the less strong and robust the can will finally be configured 20. By utilizing the pre-compression to obtain a significant portion of the differential between the innermost and outermost portions of the pattern superimposed on the final shaped can 20, the amount of actual radial expansion required to achieve the pattern is reduced. wanted. In accordance with the foregoing, the amount of tempering that needs to be applied to the can body preform 10 is also reduced. Then, the previous compression step allows the desired pattern to be superimposed on the configured can 20 with a minimum of quenching and resultant loss of strength, thus allowing the cylindrical side wall 12 of the can body preform 10 It is formed as thin as possible for this type of process. As one embodiment of the invention, the mold wall can be formed of a porous material, to allow air to escape trapped between the side wall of the can body preform and the mold wall, during operation, although Probably ventilation holes will still be required. One of these materials is porous steel that is commercially available from AGA of Leydig, Sweden. For the purposes of monitoring and quality control, the fluid pressure inside the cavity of the mold 46 is monitored during and after the expansion process, by the structure of a pressure monitor 69, shown schematically in Figure 5. Pressure monitor 69 is of a conventional construction. If the body of the can develops a leak during the expansion process, or if the irregularities in the upper flange of the can neck create a bad seal with the gas probe, the pressure inside the mold cavity will be much faster in the mold chamber 46 of what would otherwise be the case. The pressure monitor 69 will detect this, and will indicate to an operator that the body of the can could crack. In the case of steel cans, the pressure inside the mold chamber could be made high enough to form the body of the can, for example, in a protrusion type pattern, where a number of circumferential ribs are formed on the container. In Figures 7 and 9 of the drawings, there is disclosed a second method and apparatus for manufacturing a metal can body that is distinctly configured in order to improve its visual presentation for consumers. In Figures 8 and 9 of the drawings a third embodiment is illustrated. In accordance with both the second and third embodiments, a distinctive shaped metal can body is manufactured by providing a preform can body, such as the can body preform 10 shown in Figure 1, having a side wall 12 of a substantially constant diameter, then radially deforming the preform of the can body 10 in selective areas by selected amounts, to achieve an intermediate can body 74 that is radially modified, but still symmetric about its access, and then a previously selected pattern of mechanical deformations is superimposed on the intermediate can body 74. Now describing the second embodiment of the invention , a protrusion apparatus 62 of the type well known in this area of the art includes an anvil 66 and a protrusion tool 64. A protrusion apparatus 62 is used to radially deform the can body preform 10 inside the body. radially modified intermediate can 74 shown in Figure 9. The intermediate can body 74, as can be seen in Figure 9, has no deformation. on it having an axial component, and is substantially cylindrical about the access of the can body 74. Then a twisting tool 76 is used to superimpose the previously selected pattern of mechanical deformations, in this case grooved ribs, on the intermediate can body, making it possible to produce a shaped can 20 of the type shown in Figure 2.

In the third embodiment, shown in Figures 8 and 9, a centrifuge unit 68 is used to deform the cylindrical side wall 12 of the can body preform 10 radially inward from the intermediate can body 74. The centrifuge unit 68 includes, as is well known in the art, a mandrel 70 and a shaping roller 72 which is opposite the mandrel 70. After this process, the twisting step shown in Figure 9 is preferably performed on the intermediate can body thus formed 74, in a manner that is identical to that described above. In an alternative to the twisting step shown in Figure 9, the intermediate can body 74 produced by any method shown in Figure 7, or that shown in Figure 8, could alternatively be placed in an expansion die. pneumatic or mold unit 40 of the type shown in Figures 3 to 5. Then the intermediate can body 74 would expand in a manner that is identical to that described above in order to achieve the configured can 20. In the second and third methods described above, the preform of the can body 10 is also preferably partially quenched by the heat source 18 during the drying process, but, preferably, to a degree less than that of the first mode described. Preferably, annealing for the second and third methods described above is performed at a temperature that is within the range of about 375 degrees Fahrenheit (about 190 degrees Celgius) to about 425 degrees Fahrenheit (about 218 degrees Celsius). The methods described with reference to Figures 7 and 8, therefore, require less tempering than that described with respect to the previous embodiment, meaning that it is possible to have a stronger shaped can 20 at a given weight or wall thickness, or that the weight of the shaped can 20 can be reduced with respect to that produced by the first described method. However, the drawbacks of the second and third methods include more machinery and greater mechanical complexity, as well as greater wear and tear on the cans, waste, and possible damage to the decoration, as a result of processing and additional mechanical handling. However, it should be understood that, even when numerous features and advantages of the present invention have been stipulated in the foregoing description, together with the details of the structure and function of the invention, the description is illustrative only, and changes can be made. in detail, especially in the matters of shape, size, and configuration of the parts, within the principles of the invention, to the fullest extent indicated by the broad general meaning of the terms in which the appended claims are expressed. Alternatively, for example, the preform of the can body 10 could be formed by alternative processes, such as a stretch-wrap process, a stretch-thin-stretch process, or by a three-piece fabrication process or adhered.

Claims (23)

NOVELTY OF THE INVENTION Having described the above invention, it is considered as a novelty, and therefore, the content of the following is claimed as property: CLAIMS

1. A method for manufacturing a metal can body that is distinctly configured for the purpose of improving its visual presentation to consumers, which comprises the steps of: (a) manufacturing a can body preform; (b) at least partially annealing at least a portion of the preform of the can body, thereby giving the hardened portion of the can body preform greater ductility; (c) providing a mold unit having at least one mold wall defining a mold cavity conforming to the desired final shape of the can body, this mold unit being constructed of more than one part, being able to move when less one of the parts towards the other in a direction that is substantially parallel to an axis of the preform of the can body during the operation; 32 (d) placing the preform of the can body inside the mold cavity; (e) supplying a pressurized fluid inside the mold cavity, in such a way that the preform of the can body is forced by the pressure against the wall of the mold, making the preform of the body of the can assume the final desired shape of the body of the can; and (f) in a substantially simultaneous manner with the step (e), moving at least one of the mold parts towards the other in the axial direction.

2. A method according to claim 1, characterized in that the step of partial tempering is performed at a temperature that is within the range of about 375 degrees Fahrenheit (190.5 ° C) to about 550 degrees Fahrenheit (288 °) C).

3. A method according to claim 2, characterized in that the step of partial tempering is performed at a temperature that is within the range of about 450 degrees Fahrenheit (232 ° C) to about 500 degrees Fahrenheit (260 ° C) C).

4. A method according to claim 3, characterized in that the step of partial tempering is performed at a temperature that is approximately 475 degrees Fahrenheit (246 ° C).

5. A method of compliance with what is claimed in the claim 1, characterized in that the mold unit comprises three parts, and wherein the step (f) comprises moving at least two of the three parts towards the third from a first position, wherein the parts are separated from each other by holes that they open into the mold cavity, to a second position where the size of the gaps between the mold parts is reduced, while still opening into the mold cavity.

6. A method according to claim 5, characterized in that the step (f) further comprises placing the holes in the points of maximum expansion of the preform of the body of the can.

7. A method according to claim 1, characterized in that the force exerted by the pressurized fluid in step (e) is balanced with an axial force that is applied in step (f).

8. A method according to claim 1, characterized in that step (f) comprises applying an axial force to the preform of the can body, which is sufficient to exert a net compression force on the side wall of the can. the preform of the can body during step (e).

9. A method according to claim 1, characterized in that the preform of the The body of the can has a side wall that is of a substantially constant diameter.

10. A method according to claim 1, characterized in that step (b) is carried out in a lacquer or decorator oven.

11. A method according to claim 1, characterized in that step (b) is carried out during the drying of the preform of the body of the can.

12. An apparatus for manufacturing a metal can body that is configured distinctively for the purpose of improving its visual presentation to consumers, which comprises: elements for manufacturing a can body preform; elements for at least partially tightening at least a portion of the preform of the can body, thereby giving the hardened portion of the can body preform a greater ductility; mold elements comprising a mold unit having at least one mold wall defining a mold cavity conforming to the desired final shape of the can body, the mold unit being constructed of more than one part, being able to move at least one of the parties towards the other in a direction that is substantially parallel to an axis of the preform of the can body during the operation; a positioning element, for placing the preform of the can body inside the mold cavity; a fluid supply element for supplying a pressurized fluid into the mold cavity, such that the preform of the can body is forced by pressure against the mold wall, causing the preform of the can body to assume the final desired shape of the body of the can; and an axial reduction element for moving at least one of the mold parts towards the other in the axial direction.

13. An apparatus according to claim 12, characterized in that the step of partial tempering is carried out, by means of the drying element, at a temperature that is within the range of approximately 375 degrees Fahrenheit (190.5 ° C) to approximately 550 degrees Fahrenheit (288 ° C).

14. An apparatus according to claim 13, characterized in that the step of partial tempering is performed, by means of the drying element, at a temperature that is within the range of about 450 degrees Fahrenheit (232 ° C) to 36 approximately 500 degrees Fahrenheit (260 ° C).

15. An apparatus according to claim 14, characterized in that the step of partial tempering is carried out, by means of the drying element, at a temperature that is approximately 475 degrees. Fahrenheit (246 ° C).

16. An apparatus according to claim 12, characterized in that the axial reduction element comprises the molding element having three parts defining the cavity of the mold, and elements for moving at least two of these three parts towards the third from a first position where the parts are separated from each other by gaps that open into the mold cavity, to a second position where the size of the gaps between the parts of the mold is reduced, while still remaining. open into the mold chamber.

17. An apparatus according to claim 16, characterized in that the holes of the mold are placed at the points of maximum expansion of the container.

18. An apparatus according to claim 12, characterized in that the axial reduction element comprises applying an axial force to the preform of the body of the can, which is sufficient to exerting a net compression force on the side wall of the can body preform during expansion.

19. An apparatus according to claim 12, characterized in that the axial reduction element is constructed and configured to balance a force exerted on the preform of the container body by the fluid supply element.

20. An apparatus according to claim 12, further comprising a single pressurized fluid line for supplying both the fluid supply means and the axial compression means.

21. An apparatus according to claim 12, characterized in that the element for partially hardening comprises a lacquer oven or decorator.

22. An apparatus according to claim 12, characterized in that the element for partially hardening comprises a can body dryer.

23. A container made in accordance with the method described in claim 1. 2. A method for manufacturing a metal can body that is distinctively configured in order to improve its visual presentation for consumers, the which comprises the steps of (a) manufacturing a can body preform; (b) at least partially annealing at least a portion of the preform of the can body, thereby giving the hardened portion of the can body preform a greater ductility; (c) providing a mold unit having at least one mold wall defining a mold cavity that conforms to a desired final shape of the can body; (d) placing the preform of the can body inside the mold cavity; and (e) supplying a pressurized fluid into the mold cavity, such that the preform of the can body is forced by pressing against the wall of the mold, making the preform of the can body assume the final shape desired from the body of the can. 25. A method according to claim 24, characterized in that the step of partial tempering is performed at a temperature that is within the range of about 375 degrees Fahrenheit (190.5 ° C) to about 550 degrees Fahrenheit (288 °). C). 26. A method according to claim 25, characterized in that the step of partial tempering is performed at a temperature that is within the scale from approximately 450 degrees Fahrenheit (232 ° C) to approximately 500 degrees Fahrenheit (260 ° C). 27. A method according to claim 26, characterized in that the step of partial tempering is performed at a temperature that is approximately 475 degrees Fahrenheit (246 ° C). 28. A method according to claim 24, characterized in that step (b) is carried out in a lacquer oven or decorator. 29. A method according to claim 24, characterized in that step (b) is carried out during the drying of the preform of the body of the can. 30. An apparatus for manufacturing a metal can body that is distinctively configured for the purpose of improving its visual presentation to consumers, which comprises: elements for manufacturing a can body preform; elements for at least partially tightening at least a portion of the preform of the can body, thereby giving the hardened portion of the can body preform a greater ductility; molding elements comprising a mold unit having at least one mold wall that defines a mold cavity that conforms to the desired final shape of the can body; positioning elements for placing the preform of the can body inside the mold cavity; and fluid supply elements for supplying a pressurized fluid into the mold cavity, such that the preform of the can body is forced by pressure against the mold wall, causing the preform of the can body to assume the final desired shape of the body of the can. 31. An apparatus according to claim 30, characterized in that the step of partial tempering is performed, by means of the drying element, at a temperature that is within the range of approximately 375 degrees Fahrenheit (190.5 ° C) to approximately 550 degrees Fahrenheit (288 ° C). 32. An apparatus according to claim 31, characterized in that the step of partial tempering is performed, by means of the drying element, at a temperature that is within the range of approximately 450 degrees Fahrenheit (232 ° C) to approximately 500 degrees Fahrenheit (260 ° C). 33. An apparatus according to claim 32, characterized in that the step of partial tempering is carried out by means of the drying element. at a temperature that is approximately 475 degrees Fahrenheit (246 ° C), 34. An apparatus according to claim 30, characterized in that the element for partially hardening comprises a lacquer oven or decorator. 35. An apparatus according to claim 30, characterized in that the element for partially hardening comprises a can body dryer. SUMMARY OF THE INVENTION A method for manufacturing a metal can body (24) that is distinctly configured to improve its visual presentation to consumers includes, in one embodiment, the steps for providing a can body preform (10) having a wall. lateral which is of a substantially constant diameter, providing a mold unit (38) having at least one mold wall (46) defining a mold cavity that conforms to a desired final shape of the can body (24) , - placing the preform of the can body (10) inside the mold cavity (46); and supplying a pressurized fluid into the mold cavity, such that the preform of the can body 10 is pressed against the wall of the mold (46), causing the can body preform (10) assume the desired final shape of the can body (24). Preferably, an axial compression is applied to the preform of the can body, in order to reduce the internal stresses during the molding of the container. A second embodiment includes the steps of radially deforming the preform of the can body in selected areas by selected amounts to achieve an intermediate can body that Modify radially, but be symmetric about its axis; and superimposing a previously selected pattern of mechanical deformations having an axial component on the body of the intermediate can. Apparatus and related processes are also disclosed. * * * * *