Title:
Anti rotation bead
Kind Code:
A1


Abstract:
Sheet metal lid for closing can body, in which lid includes a panel and surrounding seamable edge suitable for attaching to can body. An openable area is defined on panel by a weakening line, and tab is disposed on a mounting place outside openable area. Tab has grip portion, opening portion, and attaching portion, such that attaching portion is provided for attaching tab substantially parallel with respect to panel, and tab is attached so that it is disposed with its opening portion above openable area. Near to at least one edge of attaching portion, at least one strip-shaped projection is shaped to protrude out of panel for limiting a pivoting movement (α) of tab around mounting place. The instant abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.



Inventors:
Rieck, Hajo (Gelsdorf, DE)
Gray, Martin (Flintshire, GB)
Chalk, Richard (Flintshire, GB)
Application Number:
11/089591
Publication Date:
01/26/2006
Filing Date:
11/03/2003
Primary Class:
Other Classes:
220/254.3, 220/619, 220/906
International Classes:
B65D17/34
View Patent Images:
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20070034634Hydration system with articulating port structureFebruary, 2007Brown
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20070272692Storage tank with self-draining full-contact floating roofNovember, 2007Hiner
20040000556Trash receptacles that use plastic grocery bags as liners and methods of advertisingJanuary, 2004Harris
20040000533Pressurizable containerJanuary, 2004Kamineni et al.
20090239440SMART CUP HAVING PLAY MODULE AND METHOD OF MANUFACTURING THEREOFSeptember, 2009Kang



Primary Examiner:
HYLTON, ROBIN ANNETTE
Attorney, Agent or Firm:
Sheridan Ross PC (1560 Broadway Suite 1200, Denver, CO, 80202, US)
Claims:
1. 1-53. (canceled)

54. A sheet metal lid for closing a can body, the lid comprising: a panel having a weakening line defining an openable area; a seamable edge, surrounding the panel, being attachable to the body; a tab including a grip portion, an opening portion and an attaching portion, such that the attaching portion is arranged for attaching the tab substantially parallel with respect to the panel; a mounting place positioned outside the openable area, such that the tab is arranged on the mounting place; at least one strip-shaped projection shaped to protrude out of the panel for limiting or blocking a pivoting movement of the tab around the mounting place; wherein the opening portion is arranged above the openable area, and at least one edge of the attaching portion being proximate the at least one strip-shaped projection.

55. A sheet metal lid for closing a can body, the lid comprising: a panel having a weakening line defining an openable area; a seamable edge, surrounding the panel, being attachable to the body; a tab including a grip portion, an opening portion and an attaching portion, such that the attaching portion is arranged for attaching the tab substantially parallel with respect to the panel; a mounting place positioned outside the openable area, such that the tab is arranged on the mounting place, and the opening portion is arranged above the openable area; the panel comprising at least one strip-shaped projection being arranged outside the attaching portion to block a substantial pivoting movement of the tab in a plane parallel to the panel.

56. A sheet metal lid for closing a can body, the lid comprising: a panel having a weakening line defining an openable area; a seamable edge, surrounding the panel, being attachable to the body; a tab including a grip portion, an opening portion and an attaching portion, such that the attaching portion is arranged for attaching the tab substantially parallel with respect to the panel, and includes a surface or planar extension smaller than an extension of the tab; a mounting place positioned outside the openable area, such that the tab is arranged on the mounting place, and the opening portion is positioned above the openable area; and the attaching portion comprising at least one blocking element arranged outside the extension of the attaching portion for delimiting a pivoting movement of the tab.

57. A sheet metal lid for closing a can body, the lid comprising: a panel having a weakening line defining an openable area; a seamable edge, surrounding the panel, being attachable to the body; a tab including a grip portion, an opening portion and an attaching portion, such that the attaching portion is arranged for attaching the tab substantially parallel with respect to the panel; a mounting place positioned outside the openable area, such that the tab is arranged on the mounting place; the panel comprising at least projection for limiting or blocking a pivoting movement of the tab by contacting at least one outer edge of the attaching portion.

58. The lid in accordance with claim 57, wherein the at least one projection extends over at least 30% of a width or a length of the attaching portion.

59. The lid in accordance with claim 57, wherein the at least one projection extends over at least 50% of a width or a length of the attaching portion.

60. The lid in accordance with claim 57, wherein a plurality of projections are provided near the at least one edge of the attaching portion.

61. The lid in accordance with claim 60, wherein at least one of the plurality of projections has a line or strip shape.

62. The lid in accordance with claim 60, wherein at least one of the plurality of projections has an approximate round to oval shape.

63. The lid in accordance with claim 61, wherein at least two of the projections are not equally aligned.

64. The lid in accordance with claim 57, wherein the limiting or blocking of the pivoting movement of the tab occurs through contact with the at least one projection.

65. The lid in accordance with claim 57, wherein the at least one projection is arranged between the grip portion and the opening portion of the tab on the panel.

66. The lid in accordance with claim 57, wherein the attaching portion is substantially rectangular in shape and having at least three outer edge portions.

67. The lid in accordance with claim 57, wherein the attaching portion is substantially square in shape and having at least three outer edge portions.

68. The lid in accordance with claim 57, wherein the attaching portion is connected to an articulation line on the tab, so that the opening portion is tiltable in a substantially vertically direction to a plane of the panel when actuating the grip portion.

69. The lid in accordance with claim 68, wherein the tilting movement causes an opening of the openable area along the weakening line.

70. The lid in accordance with claim 57, wherein the limiting or blocking of the pivoting movement of the tab is maintained throughout the entire vertical tilting of the tab.

71. The lid in accordance with claim 60, wherein the plurality of projections are arranged such that when horizontally pivoting the tab, each of the plurality of projections engages a single edge of the at least one edge of the attaching portion.

72. The lid in accordance with claim 57, wherein the at least one projection has a cross section which is shaped asymmetrically in a direction transverse to its longitudinal extension.

73. The lid in accordance with claim 72, wherein the asymmetrical shape includes variable steep flanks or sides that are non parallel to each other, or the asymmetrical shape includes a second steep flank that is less steep than first steep flank so as not to extend parallel to each other.

74. The lid in accordance with claim 73, wherein the first steep flank is located closer to an outer edge portion of the attaching portion than the second steep flank of the same projection.

75. The lid in accordance with claim 54, wherein the at least one projection has a height greater than 300 μm, measured from a top side facing outwards of the panel around the projection.

76. The lid in accordance with claim 75, wherein the height is substantially adapted to a height or thickness of a sheet metal of the attaching portion for the limiting or blocking of the pivoting movement of the attaching portion.

77. The lid in accordance with claim 76, wherein the height of the at least one projection is not less than substantially the thickness of the sheet metal at the respective outer edge portion of the attaching portion.

78. The lid in accordance with claim 54, wherein the at least one projection is shaped by an initial shaping or pre-forming from the panel and is structured and arranged in a final shape by a reshaping or reforming, so that a reduction in the thickness of a top side of the projection is effected during reforming.

79. The lid in accordance with claim 78, wherein a first flank is shaped more steeply than a second flank of the projection in a reforming process.

80. The lid in accordance with claim 54, wherein the at least one projection is located in a peripheral area of a rivet base zone in the lid, such that the rivet base zone is visible from an inside or a product side.

81. The lid in accordance with claim 80, wherein a part of the projection is located outside the rivet base zone.

82. The lid in accordance with claim 81, wherein more than 40% of a surface area of the at least one projection is located outside the rivet base zone.

83. The lid in accordance with claim 81, wherein the rivet base zone extends as a mounting place annularly about a rivet, which is visible from the inside or the product side.

84. The lid in accordance with claim 80, wherein the at least one projection is positioned as a secant to a tangent as a strip or a line in a edge portion of the rivet base zone.

85. A sheet metal lid for attaching a tab having an attaching portion and for closing a can body, the lid comprising: a tab including an attaching portion attached to the lid for closing a body; at least one panel surrounded by a seamable edge attachable to the body; an opening area being defined by a weakening line on the at least one panel; the at least one panel comprising a mounting place on which the tab is attachable; and at least one projection shaped to protrude from the at least one panel being structured and arranged to at least limit or block a pivoting movement of the tab through contact with at least one outer edge portion of the attaching portion.

86. A sheet metal lid for attaching a tab with an attaching portion and for substantially closing a can body, the lid comprising: at least one panel surrounded by a seamable edge that is attachable to the body; a weakening line defining an opening area on the at least one panel; the tab is attachable on a mounting place formed on the at least one panel; at least one projection arranged near but removed from the mounting place by a distance corresponding to at least to a distance of an outer edge of the attaching portion of the tab from the mounting place, after mounting the attaching portion.

87. The lid in accordance with claim 86, wherein the outer edge is an edge line facing away from the attaching portion, and wherein at least two edge lines limit a surface extension of the attaching portion.

88. The lid in accordance with claim 86, wherein said at least two edge line portions have a substantially straight-lined extension.

89. A method for shaping the sheet metal lid in accordance with claim 86, comprising: (A) shaping a pre-form of the projection out of the panel such that the pre-form is located near the attaching portion of the tab, but at a distance from the mounting place; and (B) re-forming a front edge of the at least one projection, for obtaining a better blocking for an associated outer edge portion of the attaching portion.

90. The lid in accordance with claim 89, shaping the pre-form of the at least one projection, followed by a score line shaped into the at least one portion of the panel.

91. The lid in accordance with claim 90, re-forming includes an embossing by which a top side of the at least one projection is flattened and stiffened.

92. The lid in accordance with claim 91, wherein the method includes a stiffening having a reduction of a sheet metal thickness by at least 10%.

93. The lid in accordance with claim 57, wherein the projection has the length of more than 80% of the width of the attaching portion.

94. The lid in accordance with claim 54, wherein a plurality of projections are located near at least one portion of two or more edges of the attaching portion.

95. The lid in accordance with claim 60, wherein the at least one projection extends in a longitudinal direction of the tab and has a length that is not more than 50% of a longitudinal extension of the attaching portion, and in combination with a distance of the outermost end of the at least one projection from a center of the mounting place of the more than 50% of the longitudinal extension of the attaching portion.

96. The lid in accordance with claim 60, wherein at least three projections are arranged, two of which extending substantially parallel to a longitudinal axis of the tab and one extending substantially perpendicularly to the axis.

97. A sheet metal lid comprising: a panel portion coupled to an attachable tab through a substantially flat attaching portion of the tab; a mounting element on which the tab is arranged; at least one projection extending upwards from the panel portion which is structured and arranged with at least one front stop edge for at least limiting or blocking a horizontal rotation movement of the tab.

98. The lid in accordance with claim 97, wherein the mounting element is on a rivet integrally formed with the panel portion.

99. The lid in accordance with claim 97, wherein the at least one front stop edge is linear.

100. The lid in accordance with claim 97, wherein the at least one front stop edge extends over more than half of a width or at least 30% of a length of the flat attaching portion.

101. The lid in accordance with claim 97, wherein the at least one front stop edge is substantially perpendicular to a longitudinal plane extending along a length of the tab.

102. The lid in accordance with claim 97, wherein the at least one projection is formed by; (A) forming a front stop zone from a portion of the panel, and (B) re-shaping the stop zone into a shape which has a stop edge or re-shaping the stop zone into a shape which has the stop edge that is steeper or sharper than the stop zone shaped previously.

103. The lid in accordance with claim 97, wherein at least two stop edges are provided substantially parallel to a longitudinal plane extending along the length of the tab.

104. The lid in accordance with claim 98, wherein the at least one projection from the panel is shaped in an area corresponding to a periphery of a rivet base portion or an embossed portion around the mounting place.

105. The lid in accordance with claim 97, wherein the at least one projection is flattened on a top side thereof, and having a wall thickness being reduced thereof.

106. The lid in accordance with claim 105, wherein the reduction is provided by an embossing operation.

107. The lid in accordance with claim 105, wherein a steeper edge of the at least one projection comprises at least one portion extending at an angle of substantially 90° with respect to the panel.

108. The lid in accordance with claim 97, wherein the at least one projection or the at least one stop edge has a greater width than a height and a greater length than width.

Description:

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to the provision of a positional fixing of a tab on a sheet metal lid for attaching to a body of a beverage can.

2. Discussion of Background Information

Tabs which are also called Stay on Tabs, e.g., SOT, are attached to sheet metal lids and are known devices for opening beverage cans, so a consumer can gain access to a liquid within the beverage can. When the tab is in an attached condition to the sheet metal lid of the beverage can the tab provides for a consumer to open an openable area in the surface of a lid (usually designated as “panel”). For example, the tab is taken at a grip end of the tab and raised with a vertical tilting motion, so as to break open the openable area of the lid along a line of weakness (usually called score line).

Particularly when large opening ends (LOEs) are used for the openable area, difficulties are encountered in the related art when arranging the positioning of the tab along the line of weakness (or score line), when the tab is in an attached condition to the sheet metal lid. U.S. Pat. No. 5,799,816 (Schubert) attempts to deal with the above problem, by arranging an attaching portion (or “rivet island”) of the tab to be secured to the panel of the sheet metal lid through a shaped rivet. The shaped rivet provides for an anti-rotation feature which maintains proper alignment of the tab and particularly its nose portion, so as to minimize failed openings. See FIGS. 2 and 4 and Col. 3, lines 63-67 and Col. 5, lines 37-44 of Schubert.

The instant invention addresses the technical problems related to the positional alignment of the tab in the attached condition, as well as the manufacture and reliability of the anti-rotation block.

SUMMARY OF THE INVENTION

The present invention improves the positional alignment of a tab in an attached condition arranged on a panel, as well as improve the manufacture and reliability of the anti-rotation block.

According to one feature of the invention, a sheet metal lid can be used for closing a can body. The lid may include a panel portion and a seamable edge that surrounds the panel, so the edge can be adapted for attaching to the can body. An openable area defined on the panel includes a weakening line, wherein a tab can be disposed on a mounting place outside of the openable area. The tab embodied according to the invention may include a grip portion, an opening portion, and an attaching portion. The attaching portion can be provided for attaching the tab substantially parallel with respect to the panel, such that the tab as attached is disposed with its opening portion above the openable area. Further, near the at least one edge of the attaching portion, at least on strip-shaped projection can be shaped to protrude out of the panel for a limiting pivoting movement (α) of the tab around the mounting place.

According to another feature of the invention, the projection need not protrude through an opening in the attaching portion, and the attaching portion does not need to be provided with an opening for the above purpose. Instead, the attaching portion can be kept whole, and a blocking element is provided to act on the attaching portion from an outside arrangement.

In order to obtain the blocking effect, which may also be a limiting effect, —or to completely prevent a rotating movement of the tab up to a substantial limit of the rotating movement, an outer edge of the flat attaching portion (rivet island) abuts against the projection that is shaped to protrude out of the sheet metal lid. Since the projection has positional stability on the panel in all operating positions, even when starting to break open the openable area, and since the attaching portion is substantially coplanar with the panel of the lid, tightly surrounding the central rivet as a mounting place, none of the above elements provided for preventing rotation operationally moves apart with an opening movement of the tab. Since the opening movement is a vertical tilting motion, anti-rotation is unaffected due to an outer edge of the attaching portion abutting on the panel projection.

Advantageously, a peripheral edge on a known tab within the art may also be used, since the edge does not have to be specifically arranged for obtaining the rotation barrier effect after the attachment of the tab to the panel (“staking”). The only manipulation is effected on the sheet metal lid itself, which is provided with a shape, as is the rivet in a preliminary phase, which shape may preferably also be pre-formed together with the formation of the rivet and modified in shape, or more precisely “reformed” subsequently, in a further processing step of the sheet metal lid being manufactured. The projection may thus be formed integrally with the sheet metal lid, as is the mounting place by one-piece manufacturing for the attaching portion of the tab.

The projection may have a strip shape (or line shape) aligned transversely and/or parallel to a longitudinal extension of the tab (e.g., longitudinal axis or longitudinal plane), engaging at a correspondingly aligned peripheral edge of the attaching portion for its blocking effect. In a longitudinal extension, the projection may extend over more than 30%, 50%, or possibly to more than 80% of the width of the attaching portion.

If the projections extend parallel to the longitudinal extension of the tab, or perpendicular to the transverse direction mentioned above, than the longitudinal extension may be shorter than the longitudinal extension of the attaching portion (rivet island) of the tab. Further, the projection may be at a position as distant as possible from the mounting place, such that at least one portion of the two peripheral lines mentioned above, abuts and prevents rotation on the at least one projection when starting a rotating movement.

Arranging the attachment portion as distant as possible from the mounting place allows the greatest possible force to be exerted, which provides a blocking effect to prevent rotation of the tab by a user. In particular, the projections oriented parallel to the longitudinal extension of the tab allows for a great force to be applied for the locking effect. All three of the above structural arrangements may be used either singularly or used in a combination.

The height or vertical extension of the at least one projection, may be at least equal to or possibly greater than the thickness of the sheet metal of the attaching portion, in order to obtain a reliable fixing position. Further, the above arrangement does not impair the operating or raising the grip portion, since the attaching portion is reliably situated on the other side of the mounting place and coplanar with the panel section surrounding the rivet (button coin area).

Several projections may be provided, but not all projections have to be assigned to the same outer edge portion of the attaching portion. The projections may also be differently embodied, i.e. strip-shaped, round to oval, or a combination thereof. If a line-shaped outer edge portion of the attaching portion is provided, a line-shaped (strip-shaped) embodiment of the projections may be advantageous. The line-shaped strip design may also be achieved by arranging at least two punctiform projections in line, which then form a group that is assigned to the same outer edge portion of the attaching portion.

The attaching portion in the form of a mounting tongue can be connected to the rest of the tab via a buckling portion in the form of an articulation line, i.e. integrally. It is thus provided between the opening portion (the rupture nose) and the grip portion which can be provided with a hole.

If the attaching portion is substantially rectangular, the substantially rectangular, flat, attaching portion can be formed by using the articulation line and three edge lines. Particularly, the flat or surface portion can be square in shape, and the rivet head positioned closer to the articulation line, so as not to be centrally arranged after mounting. The distance of the outwardly directing peripheral edge can therefore be larger than half the longitudinal extension of the attaching portion, so that a correspondingly improved force effect is achieved when a projection on the panel can be assigned to the peripheral edge farthest from the mounting place.

Further, it is possible for at least one of the projections to have an asymmetrical cross section, so as to have a steeper flank facing the attaching portion than the flank facing away from the attaching portion. The above configuration may also be selected for example, for the punctiform or oval projections.

According to another feature of the invention, a subsequent reshaping, reforming, or post-forming may include the reduction of the thickness of a top side of the (strip-shaped) projection, thus, achieving the solidification of the portion together with the projection as a whole. The score line may also be applied simultaneously with the reforming as mentioned above.

The result of reforming can be visually apparent in a flattened top side. Thus, the projection mentioned above can have a larger width than its total height. Further, the respective longitudinal extension of a projection can be considerably larger than the width of the projection. This can apply to elongated strip-shaped or line-shaped projections. When a steeper flank portion is formed it can be more pronounced than the preform. Further, a peripheral edge may be obtained having (at least) one portion extending at an angle substantially 90° relative to the plane of the panel. This applies to the edge opposing the assigned peripheral edge portion of the attaching portion. An embossing process also helps to give a stronger or steeper shape to the flank, the embossing provides for the reinforcement of the reformed sheet metal on the top side.

Further, if several projections are provided they do not have to engage the same edge line of the attaching portion at the start of a rotating movement, but instead may be assigned to different outer edges.

A still unfinished sheet metal lid is prepared to receive a tab includes the formation of the projection that is sufficiently positioned to be distant from the intended mounting place (from the re-formed rivet or its preform). Further, at such a distance the outer edge in the form of an edge of the attaching surface (rivet island) facing away from the future rivet can be located very close to the projection, thereby achieving the rotation stopping effect. Furthermore, since the location is in the outer edge portion of a rivet head zone or the “rivet base”, it can extend visibly around the formation of the rivet center remaining from the rivet perform.

The projection arranged as a line or strip can be positioned at least partially outside the weakened rivet base portion, in which the sheet metal may be thin due to the shaping of the mounting place. The above arrangement can address a peripheral portion of the rivet base zone which may be more than 40% of an assumed surface of a strip-shaped projection lying outside the rivet base zone.

The rivet base zone can be arranged to visibly change the surface remaining on the inside of the sheet metal lid after the rivet has been formed and the tab has been mounted. Since the projection is placed in the outer portion, i.e. as distant as possible from the weakened sheet metal or the thin sheet metal, the re-formed portion may be considerably higher before the sheet metal is damaged. Further, the re-forming may achieve heights that can be above a sheet metal thickness of the attaching portion of the tab.

The projection may be provided with a strip shape, as well as be designed to have a length longer than the diameter of the finished rivet head.

The attaching portion can be formed from a piece of the central portion of the tab, in which only minor gaps are visible between the attaching portion, which is displaced downwards to a lower plane by a double buckling line, and the parallel plane of the rest of the tab, which may be somewhat higher. Accordingly, the mounting of the projections on at least one of the free peripheral edges facing outward from the attaching portion may be barely visible from the outside, so that the rotation blocking is virtually invisible to the observer. A colored tab does not necessarily have to change in a colored shape.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described in the detailed description which follows, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein:

FIG. 1 shows the first stage of three stages in a manufacturing process of a sheet metal lid, which introduces, in part, a score line or weakening line, U-shaped bead and mounting place;

FIG. 2 shows the second stage of three stages in a manufacturing process of a sheet metal lid, which introduces, in part, beads along the tab, finger depression and an eyeball shaped bead;

FIG. 3 shows the third stage of three stages in a manufacturing process of a sheet metal lid, which introduces, in part, an attaching tongue, tab, buckling line and open position;

FIG. 4 is an enlarged section from FIG. 3, particularly showing the attaching portion 31 and the rivet 11 as mounting place;

FIG. 4a is a cross section along line C-C in FIG. 4;

FIG. 5 is an alternative configuration for the positional fixing of attaching portion 31 and thus of the entire tab 30;

FIG. 5a is a sectional view through the center plane of FIG. 5, alternatively through the vertical longitudinal plane 100 of FIG. 3;

FIG. 6 is an alternative arrangement of projections for blocking rotation of the tab;

FIG. 7 is another alternative arrangement to FIG. 6;

FIG. 8 is a cross section along a longitudinal plane 100, to illustrate a sharp front edge 20a of a strip-shaped or line-shaped projection 20;

FIG. 8a is a cross section of an embodiment of the invention corresponding to the illustration in FIG. 8;

FIG. 9a is a schematic explanation of the effective torques in a projection extending parallel to the center plane 100;

FIG. 9b is a comparable explanation of the effective torques in a projection 20 located transversely to the center plane 100; and

FIG. 10 is an illustration of a portion 11a around a rivet 11, the portion being visible from the inside of the lid, a projection 20 being visible as an outwardly vaulted cavity. This figure identifies only a section around a rivet 11 as a mounting place.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

FIGS. 1 to 3 show a sheet metal lid having a visible edge portion 12 suitable for seaming to a body of a beverage can. The sheet metal lid can be produced from thin sheet metal, typically less than 0.24 mm, which may have already passed through previous workstations before reaching the stage shown in FIG. 1. Further, the lid may include an inner surface portion or panel 10 that can be surrounded by a seamable edge 12. Further, within the panel 10, a weakening line 16 can be provided around an openable area, wherein the openable area may be surrounded by a substantially U-shaped bead 18. The bead opens towards the center portion of the panel, wherein the substantially O-shaped weakening line 16 is designed as a score line. A transitional section that is not scored serves as a connecting portion to the rest of panel 10, when the openable area 17 is broken in and along the score line 16 by the effect of a tab.

A mounting place 11 is positioned approximately in the middle of the panel. An attaching portion 31 or a sheet metal tongue can be part of the tab (FIG. 3), which can be integrally formed via an articulation line or a buckling line 38. The tab 30 can include a grip portion 32 that may be arranged with a circular opening, so the tab 30 can be operated by the user for breaking open the score line 16. See FIG. 1. The tab 30 may also include an opening portion 33 arranged before the attaching portion 31, wherein the opening portion may be located as a rupture nose above the openable area 17. Further, an additional eyeball-shaped bead 18a (FIG. 2) can be provided to reinforce the transverse LOE (large opening ends) openable area, resulting in an arrangement in which the applied forces from the opening forces are able to rupture the starting portion or arcuate end of the score line 16. The mounted tab 30 may be substantially parallel to the panel, so as to be slightly bulged or not exactly arranged in one place, through an area around the mounting place 11. Further, the mounting place 11 can be substantially planar so as to allow for a substantially parallel arrangement of the attaching tongue of the tab 30.

FIGS. 1, 3 and 5 show the longitudinal midplane 100 extending in a direction to the longitudinal extension of the tab 30, as well as a transverse plane 101 (FIG. 5) extending perpendicularly thereto.

The grip portion 32 (of an attached or staked end) of the tab 30 overlaps a finger depression 13, which is provided in the panel 10, at approximately the same distance as the inner reinforcing bead 18a on the other side of mounting place 11. The tab 30 may only be attached (FIG. 3) during the manufacture of the finished sheet metal lid. Prior to the completion of manufacture of finished sheet metal lid, the mounting place 11 may initially be formed as a bubble to permit the attaching portion 31 of the tab 30 to be attached to the panel 10. FIG. 1 shows three strip-shaped projections 20, 21 re-formed as upwardly protruding beads (i.e. towards the outside of the sheet metal lid) around said mounting place 11. The bead 20 can extend transversely to the midplane 100 which may be longer than the two neighboring beads that can extend parallel to the midplane 100. FIG. 4 shows detailed view via 21a, 21b of a possible arrangement of the longer bead 20 with respect to the attaching tongue 31.

FIG. 1 shows the attachment tongue 31 and the distances of the beads 20, 21 from the mounting place 11. At a particular manufacturing station, the re-forming of the three beads 20, 21a, 21b results in a formation of the beads (or projections). See FIG. 3. At the above manufacturing station, the projections are re-formed integrally from the sheet metal lid or panel 10 so as to extend in a vertical direction at least to a height h that is equal to the sheet metal thickness of the attaching portion 31 of the tab 30. Further, the projections are then provided with correct profile geometries.

FIG. 3 shows the rivet head in a forming process with a larger diameter than is shown in FIGS. 1 and 2, wherein the tab 30 is placed over the rivet shaft. While the rivet head is forming, the tab 30 is attached to the panel 10 via the attaching portion 31, wherein the attaching portion 31 can be connected to the rest of the tab 30 through a buckling line 38. The opening section 33 can be located above the openable area 17 inside the score line 16, close to an additional stiffening bead 18a.

In order to ensure the rupture force and the accuracy in the breaking-open process, the tab 30 rotational movement direction is designated by α in FIG. 4.

To open the opening area 17, the front nose end of the opening portion 33 is moved away from an exact position to provide a rupture force, resulting in continued tearing until the subsequent complete opening of the opening area 17. It is obvious that the front nose end of the opening portion 33 would be moved away from the exact position that is provided to ensure the rupture force, the continued tearing and the subsequent complete opening of the opening area 17.—FIG. 4 shows the tab rotational movement α being as minimal as possible, or possibly restricting all rotational movement. FIGS. 4-6 show the three strip-shaped projections 21a, 21b and 20 being assigned to the three free peripheral edges 31a, 31b, 31c of the attaching portion 31 of the grip portion 30. A small gap 21′, 21″ and 20′ may be left between each outwardly facing edge and the respective inner edge of the each projection, for example, 31c from 20″ at the projection 20. However, the gap may also be reduced to zero on at least one of the outwardly facing edges of said attaching portion 31.

FIG. 4 shows the width of the attaching portion 31 being marked with “b”, and the two projections 21b, 21a (or beads) positioned parallel to the longitudinal midplane 100 and at a distance from the attaching portion 31 via inside edges 21b′ and 21a′. The longitudinal extension of the attaching portion 31 in the plane 100 extends over the rivet head as the mounting place 11. The length of the two beads 21a, 21b can be shorter than half the longitudinal extension of the attaching portion 31. Further, beads may be positioned as far as possible to the rear area of the attaching portion in order to apply the greatest possible force for the locking effect or positional fixing with an assumed rotation movement α.

The above arrangmement of the locking effect (or positional fixing) with the assumed rotation movement α, may further be effected with the greatest possible distance of the projection 20 disposed in the transverse plane 101, which is transverse to the longitudinal mid-plane 100. Further, the projection 20 may be longer than two projections 21b, 21a (or beads) positioned parallel to the longitudinal midplane 100. It is possible for the projection 20 to extend over more than half or even more than 80% of the width b of the attaching portion 31.

According to another feature of the invention, it is also possible for one or more of the three strip-shaped projections or beads described above to be omitted from the attaching portion 31.

According to another embodiment of the invention, the attaching portion 31 may be arranged with one projection 20, as viewed in FIG. 5. Further, the outwardly facing edge 31c is positioned farthest from the rivet or mounting place 11 and approximate the strip-shaped projection (or geometry) 20, so as to minimize or even prevent the rotational movement α of the tab 30. It is possible to limit the rotational movement α of the tab 30 with the positioning of the projection 20 to such an extent that the opening behavior of the tab is not affected when the tab 30 is tilted upwards at the grip portion 32. The rotating movement α can be predetermined by at least two limit values, which are defined by the abutment in an assumed rotation α (in both directions about the axis of the rivet 11), resulting in limited or even possibly no rotating movement α. Further, the rotational or pivoting movement α is substantially in the plane in which the panel is disposed in an area surrounding the rivet head 11, such that the plane is kept parallel by the plane of the attaching portion 31 (which may have a planar or surface extension). The attaching portion 31 may be embodied as a rectangle or square, having two parallel peripheral edges or edges 31b, 31a and one peripheral edge 31c at a distance from the articulation line 38 and extending parallel thereto. Another embodiment may include the attaching portion 31 having an arcuate form similar to a triangular shape, or a more distant shape which may not have a straight extending peripheral edge 31c.

The cross-section shown in FIG. 4a relates to the corresponding sectional line of FIG. 4. According thereto, an asymmetrical design of the strip-shaped projections 21a, 21b is provided, a steeper flank 21b′ being located closer to a peripheral edge 31b than the less steep flank 21b″ of strip-shaped projection 21b. The same is valid for the parallel projection 21a and its associated peripheral edge 31a.

In FIG. 4a, the sheet metal lid in the panel 10 and the attaching portion 31 are parallel, with the rivet 11 (not shown). An assumed rotation movement causes the peripheral edge 31a to abut on the steeper flank of the projection 21a, or the peripheral edge 31b to abut on the steeper flank 21b′ of the projection 21b. A narrower association of the steeper flanks, due to their almost vertically extending ridges or steps, permits any minor (residual) rotating movement in the plane of the sheet metal lid of the panel 10 in the rivet zone 11 to be almost completely prevented.

FIG. 5a shows a cross section relating to FIG. 5 and arranged through the longitudinal plane 100. FIG. 5a shows one projection 20 cooperating with the peripheral edge 31c of the attaching portion 31 to prevent function-affecting rotational movements α. Further, the rivet head designed as a mounting place 11 is visible through an opening in the attaching portion 31. Also visible is the allocation of the free peripheral edge 31c to the projection 20 re-formed from the metal sheet lid, which projection 20 (see FIG. 4a) indicates that other projections 21b, 21a may also have an asymmetrical shape.

FIG. 8 shows the asymmetry in a transverse direction to the longitudinal extension of the projection 20 (in the longitudinal plane 100 of the lid or the tab). Further, the projection 20 can be associated to the peripheral edge 31c of the attaching portion 31. By a double forming process, a first pre-forming according to FIG. 1 and a second re-forming according to FIG. 2, resulting in a very steep front edge 20″ or 20a can be obtained, having a very large height h (relative to the thickness of the sheet metal). Furthermore, the projection 20 is arranged as distant as possible from the sensitive area of the rivet base 11a, in case the sheet lid is damaged which would resulting in damage to the projection 20. The steep front edge 20a (or 20″ according to FIG. 4), together with a less steeply extending second flank 20b, which provides no blocking effect with the attaching portion 31, allows higher forces to be applied. Further, the attaching portion 31 is less likely to be deformed upwards (perpendicularly to the plane of panel 10) on a more flatly extending peripheral edge and to thereby lose the blocking effect.

FIG. 8a shows the cross section extending in a longitudinal direction, as determined by the longitudinal midplane 100 for FIG. 4, 5, 8 as viewed in the bottom section. Further, the top illustration shows a preform 20*, in a two-stage manufacturing process prior to the second step (post-forming or re-forming). In a first shaping step, for example according to FIG. 1, a pre-form 20*, which may have a rampart (or ridge-shaped structure), can be shaped to protrude out of a panel 10 with two flat inclines and a middle portion extremely rounded. In a second re-forming step, (see FIG. 2), a much steeper front edge 20″ (see FIG. 4) or 20a (see FIG. 8) is obtained, while the sheet metal lid nevertheless remains undamaged. The second re-forming and the result after attaching the grip portion are shown in the lower illustration of FIG. 8a. It is understood that in both the upper and the lower illustrations, the strip-shaped projection 20 can extend perpendicularly to the paper plane, in a transverse plane 101 extending perpendicularly to the longitudinal midplane 100. The transverse plane 101 is a relative indication referring to the position of the pre-form 20*, in which there is a symmetry of the pre-form initially shaped from the sheet metal lid relative to the plane 101, that is abandoned during re-forming, as is illustrated by the finished projection 20 in the bottom representation, in which it is no longer symmetrical to the transverse plane 101.

The following embodiments refer to the bottom illustration of FIG. 8a. The rivet 11 used for attaching portion 31 to the sheet metal lid 10 can be located to the left (not shown). A rear end 31c of an attaching portion 31 is the peripheral edge that is assigned to a front edge 20″ of a projection 20, possibly leaving a narrow gap 20′ (see FIG. 4). The projection 20 is characterized by an asymmetry, with a steep front edge 20″ (or 20a) and a less steeply extending peripheral edge 20b facing outwards. As a result of re-forming, the projection may also have a plateau-shaped top side 20c, providing for the projection 20 to reach a very large height h relative to the thickness of the sheet metal, despite the relatively flat appearance of its shape. However, the width of the projection is arranged to have an increased strength with the width being larger than its height h, particularly about twice as wide as it is high, so that the essential portion of the projection 20 can be situated to the right of the transverse plane 101.

The re-forming step includes shaping the pre-form 20* with a coining (or an embossing operation) for flattening the top surface 20c. In the re-forming process, a tool is applied from the top and from the bottom for re-forming. The slight bend that is detectable on the left in the rising flank of the pre-form 20′ may be recognized in the bottom final form via the sharp front edge 20″ being introduced in the initially gently rising front incline of the shaped rampart 20*. To the right of the transverse plane 101, the second incline of the rampart is formed from bottom to top, for forming a flat shape 20c, starting approximately at the instep of said rampart 20* and leading gently over to the rest of the sheet metal panel 10 in portion 20b.

Additionally, in the final form, the attaching portion 31 and the tab 30 are already attached according to FIG. 3. The tab can be arranged with its intermediate web between the left opening and the grip opening 32b substantially above the transversely extending projection 20. The two openings of the tab are shown in figure 3, one opening resulting from the formation of the attaching portion 31, which is further connected to the tab 30 via an articulation line 38, whereas the opening for inserting a finger is designed particularly. The opening 32b is a part of the grip portion 32, the web 32a between said two openings being shown slightly bulged in FIG. 8a, having a front edge 32c that was related to the free edge 31c of the attaching portion 31 during manufacture. A major part of the projection 20 is thus located below said web and is barely visible from outside.

In this context, a modified sequence of the two-stage re-forming may be performed besides the processing sequence according to FIGS. 1 to 3. For example, the initial introduction of the pre-forms, as illustrated by the pre-form 20* in the top picture of FIG. 8a, in a first working step, shown without the introduction of score lines (as weakening lines 16). In this case multiple projections can be used to block rotating movements which may include all the pre-forms being shaped. The first score line introduced can be jointly in a single working step, in which the re-forming (further shaping) of the pre-formed projections takes place. In this step, the projections receive their correct, assigned profile, as is shown in the bottom illustration of FIG. 8a. For example, this profile is capable of being transferred not only to the transversely extending projection 20, but also to the other projections, provided that they have been shaped as pre-forms in the previous operation. In this way, a scoring operation, which subjects the sheet metal to severe stress, is not performed at the same time as the shaping of the pre-form takes place in the first operation, since the shaping process causes considerable stress to the sheet metal lid. The score line may be introduced simultaneously with the re-forming operation. During re-forming (see FIG. 8a), the wall thickness on the top side of the projection is reduced by about 10% to 15%, with simultaneous compression and solidification of the same portion, thus achieving uniformity from top to bottom by the embossing operation (or coining).

FIG. 6 shows an attachment of two substantially punctiform projections 23a, 23b to the longitudinal sides 31a, 31b of the attaching portion 31. Additionally, a projection 22 may be provided on transverse edge 31c of the attaching portion 31, wherein the projection 22 may be elongated (such as oval shape) and or substantially circular shape.

FIG. 7 shows a group of projections arranged to a single outer edge (outwardly facing peripheral line) of the attaching portion 31. The group 24 may include three individual, substantially punctiform projections assigned to the peripheral edge 31c, but may as well be assigned to the two other peripheral edges 31a and 31b. Also, only two punctiform projections can be used in FIG. 7. In the same way, the asymmetrical shape of the projections formed to protrude in upward direction in accordance with FIG. 4a, or also FIG. 5a or 8a, may also be applied to the above mentioned embodiments.

For example, one projection may be used with a peripheral edge 31c extending transversely to the longitudinal plane 100 of the tab 30, wherein the rotational movement in both directions can be prevented if the projection extends at least on both sides of the midplane. On the other hand, if a projection is arranged on a peripheral edge extending parallel to the longitudinal plane 100, then at least two projections should be provided on the two correspondingly available edges as “stop edges”, for symmetrically limiting rotational movements of the tab 30.

All the projections described may be arranged outside the attaching portion 30, in order to be able to cooperate in a blocking manner with at least one of its respective outer peripheral edges (edge).

FIGS. 9a and 9b show a top view of the attaching portion 31 disposed on the panel 10 over a mounting place 11 (or rivet head). A lateral projection 21a extends parallel to the midplane 100 of the tab 30, upon which a force is exerted on the projection due to an assumed rotation movement in a direction α. An assumed length I of the attaching portion 31 to the mounting place 11 can be located closer to the articulation line 38 than to the rear end 31c of the attaching portion 31, so that an effective power arm I1 is larger than half of the length I of the attaching portion 31. Because of the positioning of the line or strip-shaped projection 21a that is close to the rear edge line 31c, a force via a large lever arm can apply a large torque for blocking (blocking moment) an undesired rotation.

Similarly, the exertion of torques may be explained in a projection 20 that extends perpendicularly to a midplane 100, wherein the projection can substantially occupy the entire width b of the attaching portion 31 near to a rear edge line 31c thereof. In this case, the (maximum) power arm is designated b1, and in a first approximation, the lever arm is approximately (but not exactly) equal to half of the width b, marked as lever arm b1 in an assumed (hypothetical) rotational movement in a direction α as illustrated. The corresponding force via the lever arm b1 is applied by the projection 20, or the front edge 20a thereof (edge 20″ in FIG. 4). The corner of the attaching portion 31 being slightly rounded, the entire half of the width is not available for use as a lever arm, but instead between 70% and 100% of b/2, substantially in the range of between 80% and 90%.

FIG. 10 shows a thinned zone of the sheet metal lid around a rivet head 11 said zone being visible from the inside. Said rivet base zone 11a is a zone that remains on an outer side after the second re-forming of the rivet head 11, usually visibly by circular lines surrounding the center of the rivet as mounting place 11.

The “button coin area” most likely cannot withstand strong stresses, since the sheet metal is reduced in thickness due to the rivet being shaped to protrude in an outward direction. Projection 20 occupies a surface area f20 that is line or strip-shaped mounted in the outer edge zone 11b of the rivet base, or rather displaced far outside of the thin sheet metal zone susceptible to possible damage. The attaching portion 31 is marked by a dashed line showing the relative position of the “coin area”. Alternatively or cumulatively, the projection 20 can be shown as located at the rear edge 31c, where the two lateral projections 21a, 21b may also be provided. Which can result in the projections being positioned close to the peripheral zone of the rivet base and not displaced to the thinned out portion near the rivet head, which portion is susceptible to damages.

For example, a more precise dimensioning of the surface areas may show the strip-shaped projection 20 situated at least partly outside the rivet base zone (or coin area) and outside the outer peripheral portion 11b thereof. The outward displacement can be equal to at least 40% of the surface portion f20, which is no longer in the periphery 11b of the rivet base 11a, but outside thereof. This position and the position and extension of the coin area can easily be visible from the inside of the sheet metal lid.