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.
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.
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:
a is a cross section along line C-C in
a is a sectional view through the center plane of
a is a cross section of an embodiment of the invention corresponding to the illustration in
a is a schematic explanation of the effective torques in a projection extending parallel to the center plane 100;
b is a comparable explanation of the effective torques in a projection 20 located transversely to the center plane 100; and
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
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 (
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 (
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
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.—
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
The cross-section shown in
In
a shows a cross section relating to
a shows the cross section extending in a longitudinal direction, as determined by the longitudinal midplane 100 for
The following embodiments refer to the bottom illustration of
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
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
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).
a 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
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.