MXPA06003487A - Can shell and double-seamed can end - Google Patents

Abstract

A drawn aluminum can shell has a peripheral crown which is double-seamed with an end portion of an aluminum can body to provide a can end having a generally flat center panel connected by an inclined curved or straight panel wall to an inclined inner wall of an annular U-shaped countersink. The countersink has an outer wall which connects with an inclined lower wall portion of a chuckwall at a junction below the center panel, and the chuckwall has a curved or inclined upper wall portion which connects with an inner wall of the crown. The chuckwall also has an intermediate wall portion forming.a break, and the inner bottom width of the countersink is less than the radial width ofthe panel wall. The inclined upper wall portion of the chuckwall extends at an angle greater than the angle of the inclined lower wall portion of the chuckwall.

Description

iiiuiiiiiiuinu Declarations under Rule 4.17: - before the expiration of the time limit for amending the - as to applicant's entitlement to apply for and be granted to claims and to be republished in the event of receipt of patent (Rule 4.17 (ii)) for all designations amendments • - as to the applicant's entitlement to claim the priority of the earlier application ( Rule 4.17 (iii)) for all designations (88) Date of publication of the international search report: - as to the applicant's entitlement to claim the priority of the 4 August 2005 earlier application (Rule 4.17 (iii)) for all designations For two-letter codes and other abbreviations, refer to the "Guid¬ Published: ance Notes on Codes and Abbreviations "appearing at the begin DOUBLE STITCHING CAN AND EXTREME DOUBLE SEWING Environment of the invention. This invention relates to the construction or forming of a metal or aluminum foil can shell and to an end of the can having a peripheral edge or crown that is double stitched to the upper edge portion of the body of a can of sheet metal or aluminum. That end of the can is formed of a sheet metal shell, stretched metal, for example, a shell produced by machining, as described in U.S. Patent No. 5,857,374, the disclosure of which is hereby incorporated by reference. Commonly, the shaped can shell includes a circular central panel extending to a wall of the panel extending toward, or also forming, the inner wall of a reinforcing or flared rib having a cross section configuration in the shape of . The flare is connected by a generally truncated mandrel with an annular crown which is formed with a peripheral curl. For beverage containers, the central panel of the shell is commonly provided with an EZ flange to open and after the can body is filled with a beverage, the crown of the shell crimped peripherally is stitched twice to the portion of upper end of the body of the can.

When the can body is filled with a 'carbonated beverage, or with a beverage that must be pasteurized at a high temperature, it is essential that the end of the can have substantial resistance in the clamp to withstand the pressurized beverage, for example, a clamp resistance of at least 90 psi. That resistance to "clamp" pressure and "rock" pressure is described in detail in US Patent No. 4,448,322, the disclosure of which is incorporated by reference. It is also desirable to minimize the weight of the metal foil or aluminum within the end of the can, without reducing the strength of the clamp. This is achieved either by reducing the thickness or the gauge of the flat metal sheet from which the can is stretched and formed and / or by reducing the diameter of the cut circular space of the metal sheet to form the shell of the can.

There have been many sheet metal shells and can ends constructed or proposed to increase the strength of the end clamp of the can and / or reduce the weight of the metal sheet within the end of the can, without reducing the strength of the can. the clamp For example, Patents ÜS No. 3,843,014, No. 4,031,837, No. 4,093,102, the above-mentioned No. 4,448,322, No, 4,790,705, No, 4,808,052, No, 5,046,637, No, 5,527,143, No. 5,685,189, No. 6,065,634, No. 6,089,072 and No. 6,102,243, No. 6,460,723 and No. 6,499,622 describe several shapes and configurations of tin shells and tin ends, and the various dimensions and configurations that have been proposed. or used to increase the strength of the end clamp of a can and / or reduce the metal at the end of the can. Also the published PCT application No. WO 98/34743, describes a modification of the shell of the can and the end of the -lata described in the Patent No. 6,065,634. In addition to increasing the strength / weight ratio of the end clamp of a can, it is desirable to form the shell of the can so that there is a minimum of required modifications, for the extensive machining that exists in the field to add the opening EZ tabs to the can shells, and to double sew the can shells to the bodies of the cans. While some of the can shells and can ends described in the above patents provide some of the desirable structural representations, none of the patents provides all the representations.

Description of the 'invention.

The present invention is directed to an improved sheet metal shell and can end, and to a method for forming the end of the can that provides the above-mentioned desirable representations and advantages, including a significant reduction in the diameter of the space for forming a can shell and a significant increase in the endurance / weight ratio of the resulting can. A tin shell and a tin end formed from. According to the invention, not only do they increase the strength of the end clamp of the can, but they also minimize the changes or modifications in the existing machining to add opening EZ tabs to the can shells, and to double stitch the shells of the cans to the bodies of the cans.

In accordance with a representation of the invention, the shell of the can and the end of the can are formed with a general height between the crown and the flaring of less than 0.610 cm, and preferably less than 0.584 cm, and the flaring has generally a cylindrical outer wall and an inner wall connected to a curved panel wall. A generally truncated mandrel wall extends from the outer wall of the flared towards the inner wall of the crown, and has an upper portion of the wall that extends at an angle of at least 16 ° relative to the central axis of the shell, and preferably between 25 ° and 30 °. The flared may have a generally flat bottom wall or an inclined inner wall which connects to the flared outer wall with a small radius, substantially less than the radial distance of the bottom wall, and the inner width of the flare in its bottom is less than the radius of the panel wall.

According to the modifications of the invention, a can shell and a can end may have some of the structure above, and the seal being a portion of the bottom wall of the mandrel wall and the exterior flare, substantially below of the central panel. The portion of the bottom wall of the flare extends at an angle less than the angle of the portion of the top wall relative to the center axis and is connected with the portion of the top wall by a short wall portion that provides the mandrel wall. with a separation or key of interlocking 'or a configuration slightly curved in the form of S. The flare has a radius of curvature substantially smaller than the radius of curvature or radial distance of the panel wall, and the interior width of the flare at the bottom of the flare it is also smaller than the radius or radial distance of the panel wall, and preferably less than 0.089 centimeters. In a preferred embodiment, the flare has an inclined portion of the bottom wall, and the panel wall has an inclined portion of the flat wall.

Other Embodiments and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

Brief description of the drawings. Figure 1 is a vertical cross-section through a sheet metal can shell formed in accordance with the invention; Figure 2 is an enlarged fragmentary section of the can shell of Figure 1, and shows the configuration of a representation; the figure. 3 is a fragmentary section of the can shell of Figure 2, and shows the can shell becoming a can end with a double seam mandrel and a first stage roller; Figure 4 is a fragmentary section similar to Figure 3 and shows a can end in double seam with the mandrel and a second stage roller; Figure 5 is an enlarged fragmentary section of the can end with double seam shown in Figure 4, and with 'a fragment of the modified double seam mandrel; Figure 6 is a section similar to Figure 1 and shows a can end with double seam formed in accordance with the invention; Figure 7 is an enlarged fragmentary section similar to Figure 2 and showing a can shell formed in accordance with a modification of the invention; Y Figure 8 is an enlarged fragmentary section similar to Figure 5 and showing the can shell 'of Figure 7 with double seam in a can body; Figure 9 is an enlarged fragmentary section similar to Figure 7 and shows a can shell formed according to another modification of the invention; Figure 10 illustrates the stacking and nesting of the can shells formed as shown in Figure 9; Figure 11 is an enlarged fragmentary section of the mandrel wall of the can shell shown in Figure 9; Figure 12 is an enlarged fragmentary section similar to Figure 9 and showing a can shell formed according to another modification of the invention; Y Figure 13 is an enlarged fragmentary section similar to Figure 12 and showing a can shell formed according to another modification of the invention.

Description of preferable representations. Figure 1 illustrates a one-piece shell (10), which is formed of a substantially circular sheet metal or aluminum space, preferably having a thickness of about 0.0216 centimeters and a space diameter of about 6,871 centimeters. The shell (10) has a central axis (11) and includes a central panel (12) slightly crowned with an annular portion (14) extending towards a curved wall (16) of the panel. The central portion (14) of the panel wall and the wall (16) of the panel can be formed by a series of combined curved walls having radii in which Rl is 3,782 centimeters, R2 is 0.815 centimeters, R3 is 0.787 centimeters, and R4 is 1,140 centimeters. The curved wall (16) of the panel has an interior diameter Di at the bottom of about 4,712 centimeters.

The curved wall (16) of the panel with the radius R4 extends from an inner wall (17) of a reinforcing rib or flare (18) having a U-shaped cross-sectional configuration and including a wall (22). ) annular plane at the bottom and a generally cylindrical outer wall (24) having an inner diameter D2, for example, of about 4,971 centimeters. The flat wall (22) of the bottom of the flaring (18) is connected to the wall (16) of the inner panel and to the outer wall (24) of the flaring through the curved corner walls (26), each with a radius, R5 interior of about 0.025 centimeters. The width W radial.de the flat wall (22) of the bottom is preferably about 0.056 centimeters, so that the width Wl of the inner bottom of the flared (18) is about 0.107 centimeters.

The outer wall (24) of the flared (18) connects with a generally tronconical mandrel wall (32), through a curved wall (34) having a radius R6 of about 0.137 centimeters. The mandrel wall (32) extends at an angle Al of at least 16 ° with respect to the central axis (11) or to a vertical reference line (36) which is parallel to the central axis (11) of the shell. Preferably, the angle Al is between 25 ° and 30 ° and of the order of 29 °. The upper end of the mandrel wall (32) connects to the bottom of an inner curved wall (38) of a round crown (42) having a wall (44) curly exterior. Preferably, the inner wall (38) of the crown (42) has a radius R7 of about 0.178 centimeters, the diameter D3 inside the bottom of the inner curved wall (38) is about 5179 centimeters, and the outer diameter D4 of the outer curly wall (44) is about 5,944 centimeters. The height C of the outer curled wall (44) is within the range of 0.191 centimeters and 0.241 centimeters, and is preferably about 0.201 centimeters. The depth D from the bottom of the outer curled wall (44) or of the joint (46) of the mandrel wall (32) and of the wall (38) of the inner crown, to the inner surface of the wall (22) ) from the bottom of the flaring, is within the range of 0.274 centimeters and 0.376 centimeters, and preferably of about 0.320 centimeters. The connection (47) or the center point for the radius R6 has a depth G of about 0.201 from the joint (46) or the bottom of the outer curved wall (44) of the crown (42).

Figure 3 shows the crown (42) of the shell (10) that is double stitched in an upper portion (48) of the peripheral end of a metal sheet or aluminum can body (50). The double stitching operation is carried out between a rotating double-stitched circular mandrel (55) that engages the shell (10) and has an outer surface (58) that may be slightly narrowed between an angle of 0 ° and 10 ° with respect to the central axis of the mandrel (55) and the common center axis (11) of the shell (10). Preferably, the surface (58) has a slight narrowing of about 4 ° and is engaged through the inside wall (38) of the crown (42) in response to the radially inward movement of a double-seam roll (60). first stage, while the body (50) of the can and its contents and the shell (10) are rotating or rotating with the mandrel (55). The mandrel (55) also has a surface (62). truncated cone that engages with and engages • the conical core wall (32) of the shell (10), and a portion (64) that projects an annular lip downwardly of the mandrel (55) extends inside the flaring (18), and has a bottom surface (66) (Figure 5) and an external cylindrical surface (68) that engages the wall (22) of the bottom and the wall (24) outside of the flared (18), respectively.

Figures 4 and 5 illustrate the completion of the double stitching operation to form a double stitched crown (70) between the rotary mandrel (55) and a double-seam roll (72) of the second stage, which also moves radially inward while the mandrill (55), the shell (10) and the body (50) of the can are rotating to convert the shell (10) into one end (75) «of the can, which is positively bonded and sealed to the portion (48) of the upper end of the body (50) of the can. The edge or the crown (70) with double stitching has an inner wall (74) which is formed from the inner wall (38) of the crown (42) of the shell, and also has an outer wall (76) formed from of the crown (42) of the shell, including the outer curled wall (44). The crown (70) with double stitching has a height H2 within the range of between 0.229 centimeters and 0.270 centimeters, and preferably of about 0.254 centimeters. The end '(75) of the can has a general height Hl between the top of the crown (70) and the bottom of the flare (18), within the range of 0.432 centimeters and 0.610 centimeters, and preferably of about 0.597 centimeters. Since the end (75) of the can has the same cross-sectional configuration as the shell (10), with the exception of the crown (70) with double stitching, the same common reference numbers are used for the common structure Figures 4-6.

As apparent from Figure 6, the central portion of the central panel (12) defines a plane (80) substantially intersecting the junction (46) of the mandrel wall (32) with the interior wall (74) of the crown (70) with double stitching. The opening tab E-Z has been omitted in Figure 6 for purposes of clarity and simplification, and since the opening tab E-Z is not part of the present invention.

Figures 7 and 8 show another representation or modification of the invention, including a can shell (Figure 7) and a double stitched can end (Figure 8). Accordingly, the structural components corresponding to the components described above in connection with Figures 1-6, have the same reference numbers but with the addition of premium marks. Thus, referring to Figure 7, a can shell (10 ') has a central axis which is the same as the axis (11) and includes a central circular panel (12 ') connected to a peripheral wall (16') of the curved panel, which is connected to an inclined interior wall (17 ') of a flare (18') having a U-shaped cross-sectional configuration. The flared has an outer wall (24 ') generally cylindrical extending at an angle less than 10 ° and connecting with a mandrel wall having a portion (32 ') of a top truncated wall and a portion (34') of a slightly curved bottom wall. The portions (32 ') and (34 ') are connected through a latching key or a generally vertical ascending short portion (35') having relatively narrow inner and outer radii, for example, of the order of 0.051 centimeters. The upper portion (32 ') of the mandrel wall is connected through a curved wall (37') to the inside curved wall (38 ') of a crown (42'), which has a wall (44 ') curved exterior.

The inner wall (38 ') of the crown (42') connects to the upper portion (32 ') of the mandrel wall at a junction (46'), and the outer wall (24 ') of the flaring (18') ) connects' with the lower portion (34 ') of the mandrel wall in a joint (47'). The vertical height Gl from the bottom of the flaring (18 ') to the key of or the ascending portion (35 ') is close to 0.218. The radius R20 is about 0.130 centimeters, and the portion (34 ') of the lower wall extends at an angle A3 of about 15 °. The flared (18 ') has a radius R9 of about 0.023 to 0.028 centimeters. Other dimensions and approximate angles for the shell (10 ') shown in Figure 7 are as follows: Cl 0.208 cms. l 0.061 cms H5 0.198 cms. C2 0.339, W2 0.160 H6 0.378"D6 4.851 /, W3 '0.086 D7 5.171 A2 0.29 ° D8 5.936 A3 15 ° D9 4.397 n A4 16 ° A6 13 ° It has been found that the particular configuration of the cross section of the can shell (10 ') provides performance results superior to the performance results provided by the can shell (10). Accordingly, details of the configuration of the can shell (10 ') include a portion (32') of the upper wall of the mandrel wall having an angle A2, relative to the central axis, of at least 16 ° and preferably within the range of 25 ° to 30 °.

The portion (34 ') of the lower wall of the mandrel wall forms an angle A3 that is close to 15 °. Wall (38 ') inside the crown (42) forms an angle A4 preferably within the range of 5 ° to 30 °, and preferably of about 16 °. The inner wall (17 ') of the flaring (18') forms an angle A6 that is greater than 10 ° and close to 13 °. The width Wl at the bottom of the flared between the inner wall (17 ') and the outer wall (24') is less than 0.102 centimeters and preferably about 0.061 centimeters. The radius R8 of the curved wall (16 ') of the inner panel is substantially greater than the width W1 of the flared (18'), and is about 0.124 centimeters.

The crown (42 ') of the shell (10') has a height Cl within the range of 0.191 centimeters to 0.241 centimeters, and preferably of about 0.208 centimeters, and a height C2 within the range of 0.305 centimeters and 0.432 centimeters, and preferably of about 0.389. centimeters. The overall diameter D8 of the shell (10 ') is about 5,936 centimeters, and the diameter D7 towards the joint (46') is of. about 5,171 centimeters. The inner diameter D6 of the bottom of the outer wall (24 ') of the flared is about 4,851 centimeters, and the difference W2 between D7 and D6 is greater than the width W1 of the flared, or about 0.160 centimeters. Diameter D9 for the center of the radius R8 is 4,397 centimeters. It is understood that if a shell of different diameter is desired, the diameters D6-D9 vary proportionally. The height H5 of the central panel (12 ') on the bottom of the flared (18') is within the range of 0.178 centimeters and 0.279 centimeters, and preferably about 0.198 centimeters. The height H6 of the shell (10 ') between the upper part of the central panel (12') and the upper part of the crown (42 '), is within the range of 0.318 centimeters and 0.470 centimeters, and preferably of about 0 : 378 centimeters.

Referring to Figure 8, the shell (10 ') is double stitched with the portion (48') of the upper end of a can body (50 ') formed using substantially the same machining as that described above in connection with Figures 3-5 to form a can end (75 '). That is, a seaming mandrel (not shown), similar to the mandrel (55), includes a lower portion similar to the portion (64) projecting within the flare (18 '), and having surfaces corresponding to the surfaces (58), (62) and (68) of the stitching mandrel (55) for engaging the wall (24 ') of the outer flaring, the portion (32') of the mandrel wall, and for forming the wall (74 '). ) interior of the crown (70 ') stitched double. As also shown in Figure 8, the wall (74 ') inside the crown (70') double sewn extends to a light angle A5 of about 4 °, and the overall height H3 of the end (75 ') of the can is less than 0.610 centimeters, and preferably of about 0.597 centimeters. The height H4 of the crown (70 ') double sewn is of the order of 0.254 centimeters, and the height H7 from the top of the crown (70') to the top of the central panel (12 ') is greater than the height H5 of the central panel, preferably of about 0.376 centimeters.

Figures 9-11 show another representation or modification of the invention that includes a can shell (Figure 9) where the structural components corresponding to the components described above in connection with Figures 7 and 8 have the same reference numbers but with the addition of double prime marks.

Thus, with reference to Figure 9, a tin shell (10 '') has a central axis which is the same as the axis (11) and includes a central circular panel (12 '') connected to a wall (16 '' = peripheral curved panel that connects to a wall (17) '') inclined interior or a flaring (18") having a U-shaped cross-sectional configuration. The flaring has a generally cylindrical outer wall (24") extending to a angle less than 10 ° and connects with a mandrel wall having a portion (32") of a top truncated wall and a portion (34") of a slightly curved bottom wall.

The portions (32"and 34") are connected by a locking key or a portion (35") of short wall generally, vertical or generally cylindrical that. it has relatively narrow inner and outer radii, for example of the order of. 0.51 centimeters. The upper portion (32") of the mandrel wall is connected to an inner wall (38") or a crown (42") having a curved outer wall (44"). Figure 11, portion (35") of the rising wall has a wedged outer surface (105) resulting in the wall portion (35") having a thickness, slightly less than the wall thickness of the portions (32"and 34") of the adjacent wall.

The inner wall (38") of the crown (42") connects to the upper portion (32") of the mandrel wall in a joint (46"), and the outer wall (24") of the flared (18") connects to the lower portion (34") of the -mandrill wall in a seal (47"). The vertical height Gl from the bottom of the flaring (18") to the key of interlocking or portion (35") of rising wall is of about 0.251 centimeters. The radius RIO is about 0.254 centimeters, and the portion (34") of the bottom wall extends to an angle A3 of about 15 °. The flare (18 '') has an inner radius R9 of about 0.053 centimeters and an outer Rll radius of about 0.041 centimeters Other approximate dimensions and angles for the shell (10 '') shown in Figure 9 are so or follow: C3 0.632 cms. Wl 0.076 cms. G3 0.114 cms D6 4.826 W2 0.119 G4 0.297 D8 5.933 W3 0.109 H5 0.206 D9 4.374 A2 0.29 ° R8 0.130 A6 0.8 ° It has been found that the particular configuration of the cross section of the shell (10") of the can provides performance results in some way superior to the performance results provided by the can shell (10 '). Accordingly, details of the configuration of the can shell (10") include a portion (32") of the upper wall of the mandrel wall having an angle A2 relative to the central axis of at least 16 °. and preferably within the range of 25 ° to 30 °. The lower wall portion 34 '' of the mandrel wall It forms an angle A3 that is close to 15 °. The inner wall (17") of the flared (18") forms an angle A6 that is less at 10 ° and close to 8 °. The width Wl of the flared in the bottom between the inner wall (17") and the outer wall (24") is less than 0.102 centimeters and preferably about 0.076 centimeters. The radius R8 of the wall (16") of the curved interior panel is substantially greater than the width Wl of the flare (18") and is about 0.130 centimeters.

The crown (42") of the shell (10") has a height C3, from the bottom of the flare (18"), of about 0.632 centimeters. The overall diameter D8 of the shell (10 '') is about 5,933 centimeters. The diameter D6 of the inner bottom of the outer wall (24") of the flared is about 4,826 centimeters, and the difference in diameter W2 is greater than the width W1 of the flared, or about 0.119 centimeters. The diameter D9 for the center of the radius R8 is about 4,374 centimeters. It is understood that if a different shell diameter is desired, the diameters D6, D8 and D9 vary proportionally. The height H5 of the central panel (12") above the bottom of the flaring (18") is preferably close to. 0.206 centimeters As shown in Figure 9, the curved panel wall (16") has a portion (107) wedged with a thickness less than the thickness of the adjacent portions of the panel wall (16").

Figure 12 shows another representation or modification of the invention and in which the can shell (110) has structural components corresponding to the components described above in connection with Figures 7-9 having the same reference numerals used in the drawing. Figure 9, but with the addition of ("100"). Then, with reference to Figure 12, the can shell (110) has a central axis which is the same as the axis (11) and includes a central panel (112) connected to a wall. (116) of curved panel that extends peripherally and has a radius of between about 0.102 centimeters and 0.152 centimeters. The panel wall (116) forms a curved bevel and connects to an inclined inner wall (117) of a flare (118) having a ü-shaped cross-sectional configuration. The inner wall (117) extends at an angle A7 of at least about 30 °, and the flared has an outer wall (124) extending at an angle of between 3 °. and 19 ° and connects with an inclined mandrel wall having a generally frustoconical upper wall portion (132) and a slightly curved lower wall portion (134).

The wall portions (132 and 134) are integrally connected by a curved portion (135) resulting in an angular break or a slightly inverse curved configuration formed by the radii RIO, R12 and R13. The upper portion (132) of the mandrel wall is connected to a portion (138) of the inner wall of a crown (142) having a curved outer wall (144). The inner wall (138) of the crown (142) connects to the upper portion (132) of the mandrel wall in a first joint (146), and the portion (124) of the outer wall of the flaring (118) connects with the lower portion (134) of the mandrel wall in a second joint (147).

The approximate preferable dimensions and angles for the shell (110) shown in Figure 12 are the following:.

C3 0.597 cms. Wl 0.074 cms. R8 0.356 R14 0.089 cms D6 4.757 W2 0.172 R9 0.074 R15 0.046 D7 5.100 W3 0.112 RIO 0.056 Gl 0.173 D8 5.936 W4 0.091 Rll 0.023 G3 0.079 D9 4.389 A3 14 ° R12 0.196 G4 0.259 A6 45 ° R13 0.053 H5 0.213 II H6 0.384 II It has been proven that the cross-sectional configuration of the can shell (210) having the dimensions and the approximate angles above provides performance results in some way superior to the performance results provided by the shells (10 ', 10" and 110) of can The wall (216) of inclined or beveled panel cooperates with the inclined inner wall (217) of the flared (218) and the small radius Rll related to increase the resistance to warping, and the walls (224 and 234) ) inclined and the wall forming portion (235) cooperate to increase the strength and prevent runoff during a drip test The curved panel wall (116) or the linear wall (216) (Figure 13) ) can also be formed with linear short wall sections in the axial cross section, thereby providing a faceted inclined annular panel wall.In addition, the declarations and advantages above, of the shell (10 ', 10"and 110)" can also apply to the can shell (210) shown in Figure 13.

Forming a shell and a can end with the profile or configuration and dimension described above, and especially the profile of the beveled panel wall (216), the flare (218) and the wall portion (234) shown in Figure 13, it has been found that the stitched end of the can can be formed of aluminum foil with a thickness of about 0.0208 centimeters, and the end of the stitched can will withstand a pressure inside the top can of 110 psi before the end of the can is rolled up. The configuration and relatively shallow profile of the end of the can also result in a stitched end of the. can with a general height of less than 0.610 centimeters, and also provide a significant reduction of more than 0.102 centimeters in the diameter of the circular space that is used to form the shell. This reduction in diameter results in a significant reduction in the width of the aluminum sheet or net used to produce the shells, and therefore a reduction in the weight and cost of the aluminum to form the ends of the cans, which is especially important in view of the large volume of can ends that are produced each year.

The shell (10) or (10 ') also minimizes the modifications that are required in the machining that exists in the field to form the crown (70 or 70') of double seam or to double sew the crown (42 '' or 142 or 242). That is, the only modification that is required in the machining to form the double stitched crown, is the replacing a conventional or standard double seam mandrel with a new mandrel having the truncated coupling surface (62) (Figure 5) and the coupling surface (68) on the mandrel bottom portion (64), which extends inside the flaring and engages the outer wall of the flaring. Conventional double stitching mandrels usually have the slightly tapered surface 58, which extends at an angle of about 4 ° with respect to the central axis of the double seam mandrel. As also shown in Figure 10, the slightly cracked or S-curve configuration of the intermediate portion (35"or 135 or 235) of the mandrel wall provides stacking of the shells in closely nested relationship in addition to increase the resistance to. Bending of the end of the can formed from the shell.

As will be appreciated by one skilled in the art, the end closures or shells described herein in Figures 1-11 can generally be manufactured using the end closure forming tools commonly known in the art. With respect to Figures 12 and 13 and the geometry or profiles of the end closure that are described with reference thereto, it is believed that numerous advantages in the process can be achieved. of manufacturing and closing the formed end using an improved process and apparatus as described in the pending U.S. Patent Provisional Application filed July 29, 2004 and entitled "Method and apparatus for formatting a metal end closure", which is It is incorporated here in its entirety as a reference.

While the shapes of the can shell and the can end described herein, and that the method for forming the shell and the can end constitute preferable representations of the invention, it is to be understood that the invention is not limited to those precise shapes of tin shell and can end, and that changes can be made therein without departing from the competence and spirit of the invention, as defined in the appended claims.

Claims (15)

1. Metal sheet tin shell with vertical center axis and curled peripheral crown adapted to be double stitched to a portion of the end of a can body formed of sheet metal, the shell comprising a central circular panel connected through a sloping wall of panel with an inner wall of a flare having an outer wall and a U-shaped cross-sectional configuration, the panel wall having an inner surface and an outer surface which are substantially straight in axial cross section, and which they extend at an angle of between 30 ° and 60 ° relative to the central axis, and a mandrel wall which extends from the outer wall of the flared to an inner wall of the crown.

2. Shell as defined in claim 1, wherein the mandrel wall includes a sloping upper wall portion and a sloped lower wall portion, and a defined angle break between the upper wall portion and the lower wall portion of the wall. the mandrel wall.

3. Shell as defined in claim 1, wherein the inner wall of the flare extends at an inclined angle generally the same as the inclined angle of the flake. the panel wall.

4. Shell as defined in claim 1, wherein the inner wall of the flared is connected to the outer wall of the flared by a curved wall portion having a radius of curvature less than one-half the inner width of the flared to the bottom of the flared .

5. Shell as defined in claim 1, wherein the mandrel wall has a lower wall portion extending at an angle of between 3 ° and 19 ° relative to the central axis.

6. Shell as defined in claim 5, wherein the mandrel wall has a top wall portion that has. end points defining a line extending at an angle greater than the angle of the lower wall portion of the mandrel wall relative to the central axis.

7. Shell as defined in claim 6 wherein the inner wall of the crown forms an angular break with a portion of the upper wall of the mandrel wall and forms an inner wall of a double seam with the body of the lafa.

8. Shell as defined in claim 1, wherein the shell has a general height, between the crown and the flared, of between 0.459 centimeters and 0.673 centimeters, and the height between a top surface of the central panel and an upper surface of the crown is greater than the height between a surface of the bottom of the central panel and a surface of the bottom of the flaring.

9. Shell as defined in claim 1, wherein the inclined panel wall 'extends at an angle of about 45 degrees.

10. Shell as defined in claim 1, wherein the flared comprises a first curved portion connected to the wall of the panel and a second curved portion connected to the outer wall of the flared, and the first curved portion has a radius of curvature substantially greater than a radius of curvature of the second curved portion.

11. Shell as defined in claim 1, wherein the radial distance of the flaring at the bottom of the flaring between the inner and outer walls of the flaring is less than a radial distance from the wall of the panel between an outer diameter of the central panel and a inner diameter of the inner wall of the flared.

12. Shell as defined in 'claim 1, • where the mandrel wall has a portion of the curved top wall with a radius of curvature greater than the radial distance of the flare to the bottom of the flare between the inner and outer walls of the flare.

13. Metal sheet tin shell that has a shaft vertical center and a curled peripheral crown, adapted to be double stitched with a portion of the end of a can body formed of sheet metal, the shell comprising a circular central panel connected by a sloping wall wall with an inner wall of a flared which has an outer wall and a cross-sectional configuration generally in the form of üthe panel wall having an inner surface and an outer surface which are substantially straight in axial cross section and extending at an angle of between 30 ° and 60 ° relative to the central axis, a mandrel wall extending from the outer wall of the flaring to an inner wall of the crown, the mandrel wall having an inclined portion of the upper wall and an inclined portion of the lower wall, the upper wall portion having endpoints defining a line extending to an angle greater than, the angle of a line defined by the end points of the lower wall portion relative to the central axis, and the inner wall of the crown defining an angular break with the upper wall portion of the mandrel wall and positioned to form an inner wall of double seam with the body of the can.

14. Shell as defined in claim 13, wherein the sloping panel wall extends at an angle about 45 degrees.

15. Shell as defined in claim 13, wherein the radial distance of the flared to the bottom of the flared between the inner and outer walls of the flared is less than a radial distance of the panel wall between an outer diameter of the center panel and a diameter interior of the inner wall of the flared.