Abstract:
An easy-to-open and optionally resealable beverage can end provides opening by pressing downward. An actuator lies flat initially to conform to stackability requirements, but is readily repositionable to a ready-to-open state. 
     In the ready-to-open state a planer surface of the actuator or tab is at a substantial angle to the can&#39;s top. A rigid body is interposed between it and the can&#39;s tear panel. The actuator is secured to the can top. Downward force ruptures the tear panel, opening the can. 
     Using a wide actuator, a shallow protrusion on the actuator enables gas-tight resealability of a can opening. The shallow protrusion has an interrupted helix and fits into the can opening. Providing tab attachment via a radiused slot allows the small degree of rotational movement needed for the helix to be turned and pull the actuator bottom sealingly abutted proximate to the perimeter of the opened area.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims U.S. provisional application 61/188,494 filed on Aug. 11, 2008 and PCT/US 09/01503 filed on Mar. 4, 2009 for priority. Both of the above previous applications and U.S. provisional application 61/067,906 filed on Mar. 3, 2008 are hereby incorporated by reference in their entireties. 
     
    
     FIELD 
       [0002]    The field of this invention is closures for receptacles particularly those closures with a frangible portion that breaks along a point or line of weakness. 
       BACKGROUND 
       [0003]    A common category of closures, particularly for aluminum cans containing carbonated drinks, is the so-called pop-top or stay-on-tab. Typically the attached tab initially lies flat against the top surface of the can end and is lifted by its extremity closest to the rim. With one point held to the can by a rivet, the tab acts as a lever for applying force against a tear panel. A lifting action causes a line of weakness surrounding the tear panel to be severed or ruptured. Both the tab and the tear panel are retained to the can end, called an “end” or “end wall”. There are many known variations of similar and related closures. 
         [0004]    One area of perceived deficiency in existing designs may be in the ease of opening. Opening can be difficult in some cases because of a lack of “purchase” particularly at the initial stage of movement of the tab. Unfortunately this is the point at which the initial rupture of the line of weakness occurs thereby requiring the greatest effort. It can be particularly difficult and painful for persons with long fingernails. Long nails tend to magnify the load on the fingernail bed. Using your fingernails to open current pop-top cans may also damage or break polished or decorated fingernails. Opening could also be difficult for those lacking strength or dexterity. 
         [0005]    Many solutions to this problem have been proposed. Some include variants of a lifted lever design. A feature of some of these designs is that the full resistive force of the tear panel is only encountered after the lever is raised somewhat to a position providing a slightly improved purchase. Other solutions include using purpose-designed tools to open a standard end. Also, there are designs that involve the user pushing down on a structure that is at a small angle to the plane of the can end. These later versions may present problems due to providing little leverage and having a very short throw. 
         [0006]    Another generally present drawback is the inability to reseal a can after its initial opening. Some approaches that might be adequate to reduce spillage or keep out insects do not seal well enough to keep a carbonated drink from quickly going flat. Proposed designs generally fall into two classes: (1) a stopper attached or integral to the tab that has a complementary shape to the dispensing opening and is repositioned over the opening and simply pressed into it; (2) a plate or other body inside the can that can be repositioned from the outside to block the opening from underneath. 
         [0007]    The latter approach tends to be complicated and would likely interfere with the stackability of the ends. The former relies on a friction fit, possibly augmented by a plastic coating or even a retaining latch. Those schemes would tend to either (a) not be gas-tight, (b) be pushed open by the force of the carbonation, or (c) be so close a fit as to be difficult to close and re-open. 
         [0008]    While the deficiencies mentioned above have given rise to many attempts at a solution, meeting the constraints for a cost-effective and practical implementation is difficult. In order to be compatible with existing can fill and assembly equipment, any structure above or below the primary plane of the can end must be extremely low profile to allow stacking of ends. At many steps in a production process ends are stacked directly upon each other, rim-to-rim. The protective coating on the bottom of a can end should not get touched by any aspect of the top of the can end below it in such a stack. This is to avoid the risk of coating damage that would cause an end to be defective 
         [0009]    Other constraints involve the cost of manufacturing. Although it may seem that only a small amount of material is used, the extremely high volume nature of beverage cans places a premium on each fraction of a gram of metal required and each fold or other discrete step in the manufacturing process. A practical solution should avoid an excess of material, mechanism, and complexity in order to be cost-effective to manufacture. Last, users are very familiar with the current style of can openings and are likely to assume that something outwardly resembling it, in fact, works like the current design. It would be desirable for a proposed new design to address this issue. 
       SUMMARY 
       [0010]    Beverage can ends employing the principles of this invention solve the problem of easy opening while accommodating the constraints of low profile for stackability and of low complexity. They employ an attached actuator configured to open the can by a short sequence of motions. An initial movement presents minimal resistance by not applying an opening force to the frangible area. The initial movements translate the actuator from a flat or stowed position to an elevated position of significantly improved purchase. That ready-to-open position also has adequate leverage to allow a modest applied force to easily rupture the frangible region. The force is transmitted via a rigid member or assembly situated between the actuator and the so-called tear panel, the frangibly openable region of the can end. 
         [0011]    Implementations following the principles of this invention allow the advantageous modality of pushing downward to impart the opening force. A user could apply a downward force with the pad of the thumb, heel of the palm, or any such means as may be desired. Pushing down is a more convenient manner of applying force in this case since the user has unobstructed access to the surface to which the force must be applied. They can also “get their weight behind it” if necessary. Some can ends consistent with the principles taught herein offer convenient, gas-tight resealability with the inclusion of little additional mechanism or material. 
         [0012]    Several approaches consistent with the principles taught herein are available for can end and actuator implementations that are initially substantially flat yet readily transform into a significantly upright position. The geometry of these upright positions provide an effective amount of leverage and adequate travel distance to rupture and then displace a tear panel into the can. 
         [0013]    Some examples of implementations consistent with this invention include a rigid foot stowed in a depression in the can end. Others include various self-erecting rigid foot structures. 
         [0014]    Can ends employing the resealability teachings of this invention have a generally squat cylindrical shaped structure called the “seal lock” that can be inserted into an opening. The seal lock can include an interrupted thread on its inserted portion for urging the actuator to sealing abutment with the surface surrounding the opening. The seal lock may be a portion of an actuator. Alternatively, urging the sealing surfaces together may be via inclined plane features of the top panel interacting with relatively flat under hang aspects of the insertable portion of the seal lock. 
         [0015]    One way of sealingly engaging the seal lock is to provide for an amount of rotational degree of freedom about the center of the seal lock to allow turning an interrupted thread and locking the seal. Suitable rotational geometry can be implemented by a structure as low cost as a pin in an arcuate slot. 
         [0016]    This summary is intended to introduce the inventive concepts, principles and embodiments, not to define them. 
     
    
     
       DESCRIPTION OF DRAWINGS 
         [0017]      FIG. 1  shows a perspective view of a can with one version of an end consistent with the teachings of the present disclosure; 
           [0018]      FIG. 2  is an enlarged plan view of the end of the can of  FIG. 1  in the initial, closed position; 
           [0019]      FIG. 3A  is an exploded view of the can end of  FIG. 2 ; 
           [0020]      FIG. 3B  is an exploded view as in  FIG. 3A  but from a lower vantage point; 
           [0021]      FIG. 4A  is a cross section view of the end of  FIG. 2  taken on the line A-A; 
           [0022]      FIGS. 4B and 4C  are the view of  4 A with the end in other states of openness; 
           [0023]      FIG. 5A  shows a perspective view of the end of  FIG. 2  with the actuator&#39;s extremity partially lifted upward from the plane of the top panel, and  FIG. 5B  is the same view with the actuator lifted to the extent that the can is opened; 
           [0024]      FIG. 5C  shows the end of  FIG. 2  with the actuator returned to the drinking position; 
           [0025]      FIG. 6A  is a perspective view of the end of  FIG. 2  with the actuator turned 45-degrees clockwise from its initial position; 
           [0026]      FIG. 6B  is a cutaway view along the line B-B of  FIG. 6A  with the actuator at 90-degrees from its initial position; 
           [0027]      FIG. 6C  is a cutaway along the line C-C of  FIG. 6A  with the actuator at 135 degrees clockwise from its initial position; 
           [0028]      FIG. 6D  is an enlarged portion of  FIG. 6C ; 
           [0029]      FIG. 7A  is the can end and point of view of  FIG. 6A  with the actuator at the 180-degree from stowage position, and ready-to-open; it includes a user&#39;s finger in position to press downward on the actuator; 
           [0030]      FIGS. 7B and 7C  show the can end of  FIG. 6A  in a just-opened state from various points of view; 
           [0031]      FIGS. 7B and 7C  are cutaway views along C-C, from a higher and a lower point of view respectively; 
           [0032]      FIG. 7D  is a perspective view showing only the opened base of the can end of  FIG. 2 ; 
           [0033]      FIG. 7E  is a perspective view showing the can end of  FIG. 2  in the drinking configuration; 
           [0034]      FIGS. 8A ,  8 B, and  8 C are perspective views of a second version of a can end having a self-erecting foot design; the actuator is shown respectively in the initial position, 135-degree turned position and 180-degree, ready-to-open position; 
           [0035]      FIG. 9  shows the actuator of the design of  FIG. 8A  in isolation; 
           [0036]      FIGS. 10A ,  10 B, and  10 C are views of the actuator and stop of  FIG. 9  (in isolation) from the line Z-Z with reference to the actuator; each shows a different state of rotation of the actuator, respectively at 135-degrees, at about 170-degrees, and at 180-degrees in the ready-to-open position; 
           [0037]      FIG. 11A  is a plan view of an alternate third version of a can end in its initial closed state; 
           [0038]      FIG. 11B  is a perspective view of the can end of  FIG. 11A , and  FIG. 11C  is an exploded view of that same can end; 
           [0039]      FIG. 12A  is a plan view and  FIG. 12B  is a bottom view of only the actuator of  FIG. 11A , both reoriented 90-degrees from the view of  FIG. 11A ; 
           [0040]      FIG. 12C  is a perspective view of the actuator of  FIG. 12A  from below; 
           [0041]      FIG. 12D  is an elevation view of the actuator of  FIG. 12A  along the line Y-Y; 
           [0042]      FIG. 13A  is a perspective view of only the base of the apparatus of  FIG. 11A ;  FIG. 13B  is a plan view of that base; 
           [0043]      FIG. 14A  is a sectional view of the can end of  FIG. 11A  taken along the line X-X; 
           [0044]      FIG. 14B  and  FIG. 14C  are the same view as  FIG. 14A  but with the device in its lifted-open state, and its ready-to-be-opened-by-a-downward-push state, respectively; 
           [0045]      FIG. 15A  shows the can end of  FIG. 11A  in a perspective view in the just-opened-by-lifting state; 
           [0046]      FIG. 15B  shows the apparatus and point of view of  FIG. 15A  with the can end in the ready-to-drink state; 
           [0047]      FIGS. 16A and 16B  show perspective views of the apparatus of  FIG. 11A  with the actuator pivoted from its initial state to a 45-degree and a 90-degree position respectively; 
           [0048]      FIG. 16C  shows the apparatus in ready-to-open-by-pushing state in a cutaway along the line D-D of  FIG. 11A ; 
           [0049]      FIG. 16D  shows a cutaway along the line D-D in a just-opened-by-pushing state; 
           [0050]      FIGS. 17A and 17B  show a plan view of the can end of  FIG. 11A , respectively they depict a ready-to-seal state and a sealed state; 
           [0051]      FIGS. 17C and 17D  show a bottom view of the can end of  FIG. 11A ; respectively they depict a ready-to-seal state and a sealed state, in these two figures the tear panel is not shown to better illustrate the relationship of the wings and the opening; 
           [0052]      FIGS. 17E-17H  are variations of a resealable unit. 
           [0053]      FIGS. 17E and 17F  are exploded views from above and below respectively. 
           [0054]      FIGS. 17G and 17H  are bottom plan views in the ready-to-seal and the sealed states respectively. 
           [0055]      FIG. 18A ,  FIG. 18B ,  FIG. 18C ,  FIG. 19A , and  FIG. 19B  illustrate a so-called pile driver embodiment; 
           [0056]      FIG. 18A  shows a perspective view of the end in an initial state;  FIG. 18B  is a plan view while  FIG. 18C  shows the actuator-only of  FIG. 18A  separated into constituent portions;  FIG. 19A  shows an enlarged view of the actuator in a 70-degree position and  FIG. 19B  is in a ready-to-open 45-degree position to the tear panel; 
           [0057]      FIG. 20A  shows a just-opened state in a cutaway view along the line of L-L of  FIG. 18B ; 
           [0058]      FIG. 20B  is a schematic sectional view of the can version of  FIG. 18A  shown in the just-opened state, hatching illustrates various sub-portions of the integral actuator; 
           [0059]      FIGS. 21A and 21B  depict a fifth version having a reseal feature, both are perspective views showing states of opening, and  21 A has a cut-away portion to better display the central region of the can end; 
           [0060]      FIGS. 22A and 22C  show a sixth, so-called “stacked bump” version in perspective; 
           [0061]      FIG. 22B  shows the stacked bump implementation in plan view; 
           [0062]      FIG. 23  shows an exploded, schematic view of only the actuator of the can end of  FIG. 22A ; 
           [0063]      FIGS. 24A-24C  are sectional elevation views along the line W-W of  FIG. 22B ; they depict respectively: the initial state, raised about 90-degrees, and ready-to-open; 
       
    
    
     DETAILED DESCRIPTION 
     Overview 
       [0064]    In conjunction with the included drawings this detailed description is intended to impart an understanding of the teachings herein and not to define their metes and bounds. Six particular implementations, each illustrating aspects of the present teaching, are presented below. Some of the many possible variations and versions are also described. 
         [0065]    The first, second, and third examples are “rotating” versions in that a ready-to-open state is obtained via a rotational motion from the initial state. Some implementations in this category are “two-way” in that they have two modes of opening. In those designs one mode of opening involves rotating an actuator while the other involves lifting an actuator. The forth, fifth, and sixth examples detailed are “flop-over” versions. The flop-over designs provide a mode of opening in which the users&#39; initial action is the familiar tab lifting. However the action that meets resistance and opens the can results from a downward force imparted to the tab later in the opening cycle. 
         [0066]    As used in this document the terms up, upward, down, and downward are in reference to a can or can end with its bottom standing perpendicularly to the ground and its openable end facing away from the ground. Distal and central are with regard to the center of the can end&#39;s major plane and clockwise and counterclockwise are from an observer looking down on the upper surface of a can end. Also, the term translate is not limited to purely linear changes of position. 
       Rotating Versions 
       [0067]    The three initial implementation examples to be described are capable of opening in two distinct ways. They each have an actuator that pivots around a centrally located point of the can end. This pivoting or rotating is initially in a plane parallel to that of the top panel. That rotating results in the actuator being disposed in a raised, push-to-open position. The first implementation to be described outwardly resembles the current standard design. The second implementation has a self-erecting structure and the third implementation has features providing resealability. 
       First Presented Version—Two-Way Opening Resembling Current Units 
       [0068]    This first version resembles current designs at first look but adds a new mode of opening. 
       Two-Way Opening Example  
     Structure 
       [0069]    One version of a can consistent with the teachings herein and which has a rotating actuator lever is seen in  FIG. 1 . Secured to a cylindrical vessel  1  which it closes, is a can end  2  comprising a base  3  with a pivotally attached elongated actuator  4 . The base has an annular rim  5  and a generally planer circular end wall or top panel  6 . The end is for covering and closing the open cavity of the vessel. As seen in more detail in the enlarged plan view of the end in  FIG. 2 , a generally oval portion of the top panel functions as a tear panel  7 . This portion occupies about one half of the surface area of the top panel between the rim and a centrally located rivet  11 . The tear panel is largely perimeterally delineated from other areas of the top panel by a frangible line of weakness  10  possibly made by scoring or by a partial die cut. The actuator is secured by a rivet or pin flat against the top panel. 
         [0070]    As seen in  FIG. 3A  and  FIG. 3B , a hole  15  in the actuator to accommodate the rivet is reinforced by a surrounding donut  13  deformation. That hole sets the actuator off into a longer actuator portion  34  and a shorter actuator portion  35 . The shorter portion starts at the hole and terminates in an arcuate nose  9 . The longer portion starts at the hole and terminates in a finger grip  8 , initially proximate to the rim  5 . 
         [0071]    In the base beneath the actuator&#39;s initial position is a ramp pocket  12 . This ramp area is a region of the top panel directly opposite the tear panel. The ramp pocket is seen in the exploded views of  FIG. 3A  and  FIG. 3B . It is approximately semicircular in the plane of the top panel and semi-circumscribes a hole  19  in the base that is proximate to the center of the top panel. The flat side of the semicircle of the ramp pocket is flush with the adjacent areas of the top panel  6  and ramps downward uniformly as it extends in the direction of the rim. 
         [0072]    As shown in the aforementioned figures, a foot  17  is integral to the actuator and depends from it. The foot&#39;s height is fully accommodated by the deepest part of the ramp pocket  12 . This allows the actuator to lie flat against the top panel in its initial position with its foot resting in the ramp pocket. In the implementation pictured in  FIG. 3B , the foot is a debossed region integral to the actuator. It might also be implemented as a separate component affixed to the body of the actuator. The tear panel  7  and line of weakness  10  are also shown in  FIG. 3A . The tear panel has a neck  16  region providing a hinge function. Near the neck is a bead or an embossed multiplier bump  14  aspect of the tear panel. The nose  9  of the actuator rests over this bump in the initial state. 
         [0073]    Cross sectional views along the line A-A of  FIG. 2  are seen in  FIGS. 4A-4C  with the apparatus in three different states.  FIG. 4A  shows the initial state. The actuator  4  is seen flat against the top panel  6  with its foot  17  resting in the ramp pocket  12 . The nose  9  is resting just above the multiplier bump  14 . The just-opened state of one opening mode is seen in  FIG. 4B . The tear panel  7  is partially severed from the top panel and hinged downward.  FIG. 4C  shows the ready-to-open state when using the second method of opening. The actuator is displaced from its initial position and the foot, rather than the nose  9 , rests on the multiplier bump. In this position the nose rests in the ramp pocket&#39;s floor. 
       Two-Way Opening Example  
     Operation 
       [0074]    The two methods of opening the present example can end are the familiar lift-to-open method and a push-to-open method. 
       Lift-to-Open Way—Operation 
       [0075]    The lift-to-open method of opening this can end is essentially that of popular existing designs. Its inclusion provides many benefits. A novel design that looks similar to a traditional unit can avoid user frustration by allowing optional operation as a traditional unit. This mode might be said to make this version backward compatible. 
         [0076]      FIG. 5A  shows the actuator tab  4  being lifted by its finger grip  8  from a plane parallel to the top panel  6 . In that mode of opening the actuator is a class  1  lever with the rivet  11  as the fulcrum. The nose  9  presses down on the tear panel region  7 . The shorter tab portion  35  acts as the resistance arm and the longer tab portion  34  as the effort arm. (These two portions are best indicated in  FIG. 3B ). As seen in  FIG. 5B , when the finger grip is lifted, the line of weakness  10  is severed and the end is opened. In the particular drinking position shown in  FIG. 5C , the actuator has been returned to its initial position out of the way of the dispensing opening. Also shown is a frustum shaped pivot-point support  18  between the hole and the ramp floor. 
       Push-to-Open Way—Operation 
       [0077]    To initiate the push-to-open, no-lift mode of operation of the present version, the finger grip  8  extremity is first pivoted about the rivet  11 . The direction can be either clockwise or counterclockwise. This motion presents very little resistance.  FIG. 6A  shows the actuator rotated to a  45 -degree clockwise position. The finger grip end of the actuator is slightly raised from the surface of the top panel. That is due to its foot  17  being moved in the ramp pocket  12  to a location of shallower depth and thus raising the grip extremity of the actuator upward. 
         [0078]    As the actuator is further turned through the 90- and 135-degree positions shown in  FIG. 6B , and  6 C the finger grip end of the actuator continues to rise and the nose  9  turns and drops into the ramp pocket  12 . The details of the nose entering the ramp pocket are seen in the partial, expanded view of  FIG. 6D . The nose entering the ramp pocket insures that minimal resistance is encountered between the nose and the top panel  6  as the actuator progressively inclines at a greater angle due to the decreasing depth of the ramp pocket. 
         [0079]    As mentioned above, when at 180-degrees from its initial position the actuator foot  17  rests on the multiplier bump  14  of the tear panel as seen in  FIG. 7A . This is a ready-to-open position. A user could press downward on the face of the actuator and sever the tear panel, opening the can end. This could be done with a finger, palm, first, or otherwise. Many implementations of this scheme may be opened using only one hand. 
         [0080]    In this mode, opening the longer segment  34  of the actuator is configured as a class  2  lever. The fulcrum is the rivet  11  securing one end of the segment. The portion of the actuator from the rivet to the foot&#39;s  17  effective attachment point acts as the resistance arm and the portion from the foot&#39;s effective attachment point to the location of user-applied force is the effort arm. While this arrangement does not necessarily afford more leverage than the standard lift method it maintains a comparable mechanical advantage. 
         [0081]    The geometry of this mode of opening primarily affords a significantly improved purchase. By improved purchase it is meant an enhancement in the ability and ease for a person to apply a force. In the push-down-to-open way of opening, the direction normal to the surface to which the user must deliver force is unobstructed and is free to be approached in a straightforward manner. The force may be delivered with a body part or an implement not unduly limited by size or dimension. At the typical physical relationship between a user and a can that user desires to open, pressing down is much easier than lifting upward. This results in a convenient and easy to open can end. 
         [0082]    The just-opened state is seen in  FIGS. 7B and 7C  showing the tear panel  7  hinged downward from the top panel  6 . The base  3  only is seen in its open state in  FIG. 7D . This figure allows a more complete view of the tear panel severed at the line of weakness and hinged at its off center neck  16 . As pictured here, to conveniently drink from the can, the actuator may be moved back to its initial position in this version. A user can accomplish this either by continued rotation in the initial clockwise direction as seen in  FIG. 7D  or by reversing the direction and retracing its path. Either motion can return the actuator  4  to its initial position, resulting in the ready-to-drink state as seen in  FIG. 7E . This can end design is symmetric along a line through the centers of the multiplier bump  14  and the rivet  11  so the initial opening motions described above can be performed either clockwise or counterclockwise. 
         [0083]    Variations 
         [0084]    There are many possible variations of the version described above. One is to eliminate the backward compatibly. Another variation would be to make the design asymmetric allowing only one direction of initial rotation. An asymmetric version might include only one half of the ramp pocket  12 . This could be combined with an asymmetric actuator tab having an upturned rest or finger hold on one edge. That design could suggest the required rotational direction and method of opening to a user. 
       Second Presented Version—Self-Erecting on Rotation 
       [0085]    An implementation seen in  FIGS. 8A  through  FIG. 10C  features a self-erecting foot that is established as a side effect of the rotation of an actuator  44  into a ready-to-open position. The self-erecting foot “trips” out of the bottom of the actuator as it is rotated through 180-degrees to move into a push-to-open position. 
         [0086]    Self-Erecting on Rotation—Structure 
         [0087]    In  FIG. 8A  a version is seen to include a base  43  having a tear panel  47  and an elongated actuator  44 . The tear panel includes a wedge-shaped stop  150 . The actuator is rotatably held to a top panel  46  by a rivet  41  or pin. In this design the actuator is asymmetric with a folded foot assembly structure  51  of a deformable material extending perpendicular to the major axis of the actuator. 
         [0088]    As seen in  FIGS. 10A-10C  in views taken along the line Z-Z of  FIG. 9 , the foot assembly  51  shown is implemented as a single continuous metallic piece formed in the general shape of a parallelogram. One side of the parallelogram, a top leg  57 , is shown as integral to the major plane of the actuator. Opposite it in the initial state is a foot support leg  53  that is proximate and parallel to the plane of the top panel  46 . The side facing in the direction of the allowed actuator rotation is a foot  52  and its opposite side is a base leg  55 . 
         [0089]    Self-Erecting on Rotation—Operation 
         [0090]      FIGS. 8A-8C  show this can end version, respectively: in an initial state, rotated 135-degrees, rotated 180-degrees, and ready-to-open.  FIGS. 10A-10C  are partial, section views of the unit at approximately the 170-degree, 175-degree and 180-degree positions. As mentioned above these section views are taken along the line Z-Z of  FIG. 9 , remaining referenced to the actuator as it is rotated.  FIG. 10A  shows a living hinge point  54  between the foot  52  and the foot support leg  53  contacting the stop  50 . As further rotational force is applied to the actuator the living hinges at the hinge point and the opposite corner are bent open and the angles of the other two corners of the parallelogram are correspondingly reduced. 
         [0091]    This changing of shape of the foot assembly  51  raises the actuator from the plane of the top panel, as seen in  FIG. 10B . Further rotation folds the shorter base leg  55  backward and generally in the plane of the top, effectively changing the four-sided shape into a three-sided shape. In its final configuration, seen in  FIG. 10C , the base leg is restricted from further deformation by abutting a portion  56  of the underside of the actuator and the foot assembly. Together they form the general shape of an equilateral triangle. This structure provides a rigid foot extending from the actuator to the tear panel and completes the can end&#39;s transformation to a ready-to-open state. 
         [0092]    Constraints are put on the material and structure of the foot assembly in order for it to bend into position as a foot. The actuator is rotated with only a low to moderate force so at least the hinge points need to be soft. Of course, the most cost effective construction of the foot assembly is likely as an integral piece. It must bend into position relatively easily but have sufficient strength to effectively carry out its role as a foot when in the ready-to-open configuration. Particular plastics, aluminum, steel, and alloys of these and other metals are well known to those skilled in the art as possible materials. Alternatively, the various sub-parts of the foot assembly might be individual components connected by distinct hinges. In that case, the material and construction of the sub-components and that of the hinges need not be the same. 
         [0093]    Various complete can end designs that are consistent with this version may provide for an effective dispensing or drinking position in various manners. The actuator might be broken off, it might be pushed into the can opening, or it might be snapped into the opening in such a configuration as to not block a desired fluid flow. Those implementations would have a thin actuator perimeter with a shape and features complementary to those of the opening and a relatively large open central region allowing for the effective flow of liquid. 
         [0094]    In some designs it might be desirable to be able to counter-rotate the actuator back to its initial position while unfolding the foot assembly. A design of that nature would put additional constraints on the material and structure of the foot assembly. They would be such as to provide for the various hinge points connected with some more constrained hinge structures, at least to the extent of providing for one folding followed by one unfolding. 
       Third Presented Version—Resealable, Two-Way Opening 
       [0095]    The third specific implementation example is also a two-way opening design. One way to open is a rotate and then push-to-open mode. The other way is a so-called “backward compatible”, lift-to-open mode. In addition, this example embodiment has the feature of resealability in a secure and gas-tight manner. 
       Resealable, Two-Way Opening—Structure 
       [0096]    This example can end, shown in  FIGS. 11A-11C , comprises a base  103  with a pivotally attached, generally planer, asymmetric teardrop shaped actuator  104 . The base of this can end has an annular rim  105  surrounding a generally circular top panel  106 . A tear panel  107  occupies a portion of the top panel. That panel is largely perimeterally delineated from other areas of the top panel by a frangible line of weakness  110 .  FIG. 11C  shows a closed line of weakness. If a device was implemented in that manner it could risk the tear panel completely separating from the can end. A portion relatively less weakened, or an incomplete line of weakness setting off a neck would be alternative approaches. 
         [0097]    A rivet accommodating hole  119  goes through the base proximate to its center. An actuator  104  is secured to the top panel  106  by a rivet  111  or pin through an arcuate slot  132  in the actuator and the base&#39;s hole&#39;s. The radiused slot is reinforced by a surrounding oval donut  113  deformation. A relatively small arcuate nose  109  is at the extremity of the actuator closest to the radiused slot. The distal extremity  108  of the teardrop terminates proximate to the rim  105  and has an arcuate edge of approximately the same radius as the rim&#39;s. It may be desirable to modify the design shown in the drawings to allow a larger finger-hold at that extremity. The slot  132  in the actuator  104  is generally transverse to the major axis of the actuator. The slot is somewhat skewed from that transverse axis and is about 85-degrees to the major axis. The plan view of the actuator in  FIG. 12A  shows this geometry. 
         [0098]    Seen in the exploded view of  FIG. 11C  is a shallow debossed, roughly truncated-pear shaped, planer seal lock home  137  area in the base. This depressed area is opposite the tear panel and is of a similar shape and size as the portion of the actuator under which it sits in the initial state. Within the seal lock home is an even deeper ramp pocket  112 . That ramp is further described below. 
         [0099]    A generally planer bottom face  136  region of the actuator seen in  FIG. 12B  has a somewhat distorted oval shaped area depending from it called a seal lock  133 . The seal lock is located towards the distal extremity of the actuator with its major axis transverse to the major axis of the actuator bottom face. The seal lock is about 80% the width of the actuator. The particular version shown in  FIGS. 12B ,  12 C, and  12 D has two wings  134   a    134   b  generally on opposite sides of the seal lock and tilted downward. A line from the center of one wing to the center of the other wing would be about 30-degrees off the major axis of the seal lock.  FIG. 12C  is an enlarged perspective view of the underside of the actuator. It shows the seal lock  133 , the two wings  134   a    134   b  and a foot  117 . This foot operates similarly to foot elements described in previously presented versions.  FIG. 12D  is an elevation view from the line Y-Y in  FIG. 12A . It shows that both wings are generally tilted away from the bottom surface of the actuator, approximately at an angle of five degrees from the plane of the actuator bottom face  136 . That downward angle is lessened at the counterclockwise extreme in comparison with the angle at the clockwise extreme of each wing. The result is the configuration of an interrupted helix or auger thread. 
         [0100]    The base  103  in isolation is shown in a perspective view in  FIG. 13A  and a plan view is shown in  FIG. 13B . The tear panel  107  is seen to have its major axis approximately transverse to the major axis of the seal lock home  137 . Within the tear panel, proximate to the base&#39;s hole  119 , is a raised oval displacement adder or boost  14  about one third the width of the tear panel. Centered within the raised boost is a depressed oval stop  135  with the same orientation as the enclosing oval boost. When the foot drops into it, this stop provides an alignment function stopping the pivoting of the actuator at the proper location. The surrounding oval boost increases the displacement of the primary plane of the tear panel without requiring a longer foot and deeper pocket. It also serves to strengthen the tear panel and better distribute any downward opening force of the actuator. The ramp pocket  112  starts flush with the top panel just outside the line of weakness  110  and proximate to one side of the rivet hole  119 . It turns in an arcuate manner around the pivot point support  118  as it descends to a depth accommodative of the height of the foot as the ramp floor extends toward the rim  105 . 
         [0101]    Similar to the previously described rotating actuator version, this version has two modes of opening. The operations are discussed below.  FIGS. 14A-14C  are cross sectional views of the device of  FIG. 11A  all taken along the line X-X.  FIG. 14A  shows the device in its initial state as pictured in plan view in  FIG. 11A . The actuator  104  is seen flat against the top panel  106  with its foot  117  resting in the ramp  112 . 
         [0102]      FIGS. 14B and 14C  depict the two modes of opening. They are analogous to the modes of opening of a previously presented implementation. In  FIG. 14B  the can has been opened in a manner in which the major axis of the actuator remains in a plane generally perpendicular to the top panel  106 . The distal end  108  of the actuator is raised and the nose  109  is pushed down to the tear panel. In  FIG. 14C , the actuator has been rotated 180-degrees about the rivet  111  (not visible in these sectional views) and the foot  117  is over the depressed stop  135 . 
       Resealable, Two-Way Opening—Operation 
     Lift-to-Open Way 
       [0103]      FIG. 15A  shows the actuator  104  being lifted, thus creating a lever action with the rivet  111  as the fulcrum. The nose  109  presses down on the tear out region  107 , the line of weakness  110  is severed and the end is opened.  FIG. 15B  shows the drinking position with the actuator returned to its original, flat position. 
       Push-to-Open Way 
       [0104]    To initiate the push-to-open, low effort mode of operation of this version, the actuator  104  is pivoted about the rivet  111  in a clockwise direction. As seen in  FIG. 16A  this can be accomplished by a tangential force on the finger holds  131   a    131   b.  Similar to the previously described device, the foot  117  (unseen from this view) rides up the ramp, raising the distal end  108  of the actuator as it is pivoted. As the actuator  104  is further turned through the positions shown in  FIGS. 16B and 16C , its distal end continues to rise from the plane of the top panel  106  and the nose  109  turns in to the ramp pocket  112 . The pivot-surrounding oval donut  113  rests on the pivot-point support  118 . 
         [0105]    When 180-degrees from its initial position, the foot of the actuator rests on the raised oval boost  114  of the tear panel  107  as seen in  FIG. 16C  and is in a ready-to-open position. A user can press downward on the upward facing surface of the actuator to easily open the container. The just-opened state is seen in  FIG. 16D  showing the tear panel hinged downward. 
         [0106]    To conveniently drink from the can, the actuator  104  is moved back to its initial position by reversing the direction rotation as seen in  FIG. 15B . The drinking position is the same whether opened by lifting or by rotation. 
         [0107]    Reseal—Operation 
         [0108]    This implementation has the feature of resealability. The seal lock  133  depending from the bottom surface  136  of the actuator  104  is of a size that is slightly smaller than the tear panel  107 .  FIGS. 17A-17D  illustrate the locking action.  FIGS. 17A and 17B  are plan views.  FIGS. 17C and 17D  are views from below with the tear panel  107  removed for clarity.  FIGS. 17A and 17C  show the ready-to-lock state, while  FIGS. 17B and 17D  show the locked state. 
         [0109]    To reseal, the actuator is rotated in a clockwise direction  138 , as it was originally turned to open the can. Since the foot  117  no longer has the tear panel to ride across, the foot falls into the opening. In the specific version shown in  FIGS. 12B ,  12 C, and  12 D, the last part of the actuator&#39;s traverse places the leading wing  134   a  under the lip of the opening. The trailing wing  134   b  falls into the opening as seen in  FIG. 17C . 
         [0110]    The last action the user takes to complete resealing and to lock in place is to turn the actuator  104  counterclockwise as diagramed in  FIG. 17A . In this motion direction  139  the actuator rotates about a point centered in the seal lock  133 . This motion is allowed and governed by the radiused slot  132 . That slot is a segment of a circle centered at the center of the seal lock. That small rotation turns the interrupted helical wings  134   a    134   b  under a portion of the opening&#39;s lip region  130  as seen in  FIG. 17D . The wings pull the bottom face  136  of the actuator down tightly flush with the top panel area surrounding the opening. The can end is sealed and locked. To unseal, the steps for sealing are reversed. While ease of unsealing cans consistent with these teaching is not expected to be an issue, unsealing convenience may be effected by a build up of carbonation of the top panel. 
         [0000]    Variations—Two-Way with Reseal 
         [0111]    There are many possible variations of the implementation described above consistent with the teaching of the present disclosure. There could be more than two wings. An elastomeric material or coating between the bottom surface  136  of the actuator  104  and the top panel&#39;s  106  surface just outside tear panel  107  may be employed to achieve an improved seal. That optional elastomeric material might be coated on the bottom surface of the actuator or might be an aspect of the upper surface of the top panel, for example. The shape of the opening and seal lock  133  could differ from that presented. A circular opening could allow for a taper-to-taper mating between a raised area of an actuator&#39;s bottom surface and raised area surrounding a tear panel. 
         [0112]    Alternatively, rather than being fixed to a tab or actuator, a seal lock similar to that described above might be rotatably mounted to a tab rather than employing an arcuate slot to provide the second degree of freedom of movement. Rather than rotating an interrupted thread, the inserted portion of a seal lock might be expanded and raised upward by a lever or other means on the outside of the can. 
         [0113]    Variation—Alternate Site of “Interrupted Thread” 
         [0114]    There are other versions with alternate structures used to urge the sealing abutment of the bottom face of an actuator with the surrounding area. One alternative is to have a seal lock  173  with two or more flat topped underhang protrusions in place of the angled wings. To have the same screw action as the previously described system, the opposing surface to the flat underhang portions must have an “interrupted inclined plane” feature. In this version, the area of the top panel surrounding the opening is configured, possibly by stamping, to have three or more inclined plane areas  169   a    169   b    169   c  along the edge of the opening. The interaction of the flat-topped seal lock underhang with the inclined plane areas of the top panel provides the screw action sealing force. 
         [0115]      FIG. 17E  shows an actuator  164  and base  163  exploded in perspective from above.  FIG. 17F  is similar but viewed from below. The three protrusions  174   a    174   b    174   c  extend straight down from the seal lock  173 . They might be thought of as in the shape of an upside-down mushroom. Unlike the wings in previous versions the underhang surfaces are roughly parallel to the major plane of the seal lock. As mentioned above, the screw action the perimeter of the opening is comprised of three debossed inclined plane areas  169   a    169   b    169   c.    
         [0116]      FIG. 17G  is a bottom plan view of the unit in a ready-to-seal state. Note that protrusion  174   a  is adjacent to inclined plane area  169   a.  Turning the seal lock  173  in a counterclockwise direction  165  (as viewed from above) will bring the unit to a sealed state. The pivoting about the center is provided for in an analogous manor as that of the previously presented resealable version. The sealed state is shown in  FIG. 17H  note that the underhang of the protrusion  174   a  is engaged by the openings incline plane  169   a.    
         [0117]    Variation—Cupped Spring Washer Approach 
         [0118]    In any resealing implementation consistent with the principles herein, regardless of the site of the interrupted inclined plane, if any, it may be advantageous to employ curved mating areas. To better apply a continued sealing force, either or both of the top panel regions surrounding the opening and the sealing face of a seal lock assembly could have convex aspects that acted much as a Belleville washer. 
         [0000]    Making Particular can Ends Consistent with this Teaching 
         [0119]    The implementations described are manufacturable by processes well known to those skilled in the art. Some particular manners of forming a seal lock include: 
         [0120]    1—Each “wing” (whether it is 2, 3, or more) is started in the progressive die as a well being stamped into the flat floor of the tab placed close to the edge in strategic locations. The well may be long and narrow, but not necessarily so. After the well is formed for each wing it is then folded over and flattened to the outside of the tab so that it protrudes past the edge of the tab, thus creating an undercut or wing that can grab the underside of the can opening sheet metal once the tab is twisted into sealing position. 
         [0121]    2—The sheet metal that the actuator is formed out of is folded under all the way around the perimeter so as to make a rounded edge and not expose a sharp sheet metal edge. In the areas where a wing is called for on the seal lock, the sheet metal is folded back on itself again to then protrude past the edge of the tab. It might be folded back towards the center of the tab again to not expose sharp edges. The sheet metal could be rolled and then flattened so that there are no sharp, raw, or unfinished edges exposed. 
         [0122]    3—Separate wing pieces made of the same material as the tab or actuator (aluminum) are spot welded (or otherwise permanently attached) onto the underside of the actuator. These pieces might be folded one or more times so as not to expose any sharp edges. 
         [0123]    4—A formable material such as plastic is made into wing shapes and is then attached to the underside of an actuator. This could be a thermoplastic or thermoset material that is molded then attached. Alternatively a thermoset, such as a fast curing UV curing resin, is formed right on the bottom surface of the actuators while they are running through the production line. This might employ a mold to cause the resin to cure in a certain shape. An elastomeric sealant gasket could be pre-made with the wings and then applied to the bottom of the actuator. The wings could be part of the sealant but of a harder durometer material. 
         [0124]    5—In the case of a seal lock implementation with a flat overhang rather than angled wings, another method of forming the seal lock would include stamping an elongated post near the edge of seal lock and hitting the “head” of the post to produce a mushroom shape appendage. This manufacturing technique is well known and used in the construction of rivets used in current pop-top units. 
       Flop-Over Versions 
       [0125]    The previous example implementations provide for rotating into a ready-to-open state. The three particular examples that follow use a “flop-over” action rather than rotation in the plane of the actuator to get into configurations of comparable properties. 
       Forth Presented Version—Pile Driver—Structure 
       [0126]    The so-called pile driver can end design example that is illustrated in  FIGS. 18A-18C ,  19 A,  19 B,  20 A, and  20 B, has a can end base  203  with an oval tear panel  207  region of a circular, planar top panel  206 . As in other presented embodiments, a frangible line  210  delineates a tear panel from the rest of the can end. A rivet  211  or pin secures an elongated actuator  204  to the base. The actuator  204  of the unit pictured in  FIGS. 18A and 18B  is constructed substantially as a single part comprised of four segments. The four segments are: (a) an actuator base  240 , (b) a tab  241 , (c) a foot  217 , and (d) a foot support  243 . As shown in these figures these segments are interconnected by living hinges and are a single stamped part. 
         [0127]    The actuator is shown in its initial position in the plan view of  FIG. 18B .  FIG. 18C  shows only the example actuator  204  isolated and separated at its internal hinge points. One part of the actuator, the actuator base  240 , is roughly letter “W” shaped. The two lower peaks are flattened. The center, upward, peak is represented by a circular area surrounding a hole  215 . When secured to the can end base via that hole, the “W” lies flat against the top panel  206 . The open side of the W&#39;s center peak faces the center of the tear panel  207 . The largest segment of the actuator, the tab  241 , is shaped similar to an elongated, upside-down letter “U”. The two symmetric extremities of the upside down U are each, respectively, attached to the two symmetric upper extremities of the actuator base&#39;s “W”. That attachment is via living hinges  245   a    245   b  with their openable sides facing downward toward the top panel in the initial state. 
         [0128]    The third segment of the actuator, the foot support  243 , is also shaped as an upside down letter “U”. This smaller U sets within the larger U of the tab  241 , both facing in the same direction. The extremities of the foot support U attach to symmetric locations on the actuator base corresponding to the regions of the two flattened peaks of the “W” shaped actuator base. Those attachments are also via living hinges  246   a    246   b  that are openable in the direction towards the top panel  207 . The last segment, the foot  217 , is generally rectangular. At one end it is hingeably connected  260  to the inside extremity of the tab&#39;s upside-down “U” shape. At the foot&#39;s opposite end a hinge point  247  connects it to the outside of the foot support&#39;s U-shape. The former hinge opens away from the surface of the top panel while the later hinges open towards that panel. Details of the construction of the actuator can vary in numerous ways including being composed of multiple subcomponents. 
         [0129]    Pile Driver—Operation 
         [0130]    To open a can end  202  of the pile driver design of  FIG. 18A  the user initiates a positional translation by lifting the tab&#39;s extremity  208  that is proximate to the rim  205 . While this is the same initial movement with the same purchase as those associated with current standard units, the similarity stops there. Unlike in standard units, no force is applied to the tear region through the range of this first movement. 
         [0131]    As the tab is raised, the hinges  245   a    245   b  between the actuator base  240  and the actuator tab  241  open, allowing the tab end of the actuator to rise from the plane of the top panel  206  with minimal resistance. No structure is yet engaging the tear panel  207 . In  FIG. 19A  the hinge point  247  between the tab and the actuator base is closer to the distal end of the tab than are the foot support&#39;s hinge points  246   a    246   b  to that same actuator base. Therefore as the tab rises the distance will shorten between the upper (distal) terminus  248  of the foot-foot support combination and its two lower, more central extremities  246   a    246   b.    
         [0132]    This shortening forces the foot  217  and foot support  243  to swing out of the original plane of the actuator. Due to the directionality of the hinges, the direction of this self-erecting triangle is toward the tear panel  207 . As seen in  FIG. 19B , this stage of the rotational displacement of the actuator concludes with the foot support  253  stopped by the actuator base and the foot approximately normal to the tear panel. The tab rests over the tear panel at an angle of about 30-degrees to the plane of that panel. 
         [0133]    These segments reach this state due to the central portion of the foot support abutting the actuator base  240  and due to the limits on the hinge connecting the tab and the distal end of the foot. As seen in  FIG. 19A , the hinge  247  connecting the tab to foot has mutual mating surfaces  250  which are mitered. When the hinge reaches the position at which these mitered surfaces contact each other, the joint angle hits a limit. 
         [0134]    As continued force is applied to the actuator&#39;s face, a secondary hinging within the foot support  243  occurs.  FIGS. 20A and 20B  are both views of the can in the just-opened state.  FIG. 20A  is a cutaway along the line L-L line of  FIG. 18B .  FIG. 20B  is a schematic view of the actuator  204  and tear panel  207 . Although the actuator shown is composed of one piece with various segments connected by living hinges, the various portions are shown with distinct hatchings for clarity. The foot support has two portions  252   253  connected by a crease acting as another living hinge  249 . With the more central portion of the foot support stopped by the actuator base at a level orientation, the distal portion of the foot support  252  can hinge downward into the opening as the tear panel is ruptured and pushed down. This geometry effectively creates a shorter ‘swing radius’ which now causes greater radial displacement of the tear tab per unit of displacement of the actuator, thereby clearing the tab from the opening. In other words, the variable geometry initially trades off displacement for power, and then vice versa. 
       Fifth Presented Version—Self-Erecting with Reseal 
       [0135]    One example, now described, includes a self-erecting foot and resealability, combining characteristics of some designs described above. 
         [0000]    Self-Erecting with Reseal—Structure &amp; Operation 
         [0136]    This design uses an actuator  304  that is generally oval. Similar to other presented embodiments, the actuator is connected to a can end base  302  by a rivet or pin  311 . The present actuator comprises an actuator base  340 , a foot  317 , a foot support  343 , and an actuator body  341  shown in  FIG. 21A . The actuator base, foot support, and foot are each generally rectangular in shape. Hinges connect the foot, foot support and distal edge of the base, respectively end-to-end in that order. Those two connecting hinges are living hinges in this particular example as seen in  FIG. 21A . They both open, initially, in the direction of the plane of the top panel. The distal end of the foot is hingeably connected to the actuator body. That hinging connection opens in the direction opposite to that of the top panel. 
         [0137]    The actuator body  341  is hingeably attached, at its most central edge, to the actuator base  340  at an edge of the actuator base opposite to the edge to which the foot support  343  is attached. The resulting geometry has similar properties to that of the pile driver detailed above. The actions to lift the actuator and flop it over, thereby erecting a triangular structure, are analogous to those of the pile driver. The ready-to-open state with the foot  317  oriented to facilitate application of normal force to a tear panel  307  is also analogous to that of the pile driver. 
         [0138]    Other features differ from the pile driver, but are in common with the resealable version discussed previously herein. The bottom surface of the actuator body  341  is visible in  FIG. 21B . It includes a seal lock  333  with wings  334   a    334   b  in an interrupted helical configuration. This structure can seal the opening in an analogous manner to that of the rotate-to-open, resealable design presented above. An arcuate slot  350  first provides a degree of freedom of a pivoting movement about the center of the can end to allow the seal lock to be moved into position above the opening. The slot also provides a degree of rotational movement about the center of the seal lock. This allows a turning action in which the interrupted helix pulls the actuator&#39;s bottom surface securely against the top panel. 
       Sixth Presented Version—Stacked Bumps 
     Stacked Bump Design—Structure 
       [0139]    A stacked bump implementation of a flop-over approach is shown in  FIGS. 22A-22C . Similarly to other herein described versions, a base  403  includes top panel  406  region that, in turn, includes a tear panel region  407 . The tear panel has a multiplier bump  414  proximate to the can end&#39;s center. In this version the “foot” is not a single identifiable structure or subcomponent. Rather it is formed by the combined height of three bumps  450   451   452 . When in a ready-to-open configuration they are stacked, one on top of another. 
         [0140]    An elongated actuator  404  is composed of four sections and is attached flat to the top panel  406 . As shown, those four sections are comprised by a single stamped metal part with living hinges interconnecting the sections.  FIG. 23  shows an actuator of this design, for clarity, split into its four sections: (1) an upside down U shaped tab  441 , (2) a smaller U shaped base  440 , (3) a rectangular central leg portion  443 , and (4) a rectangular distal leg portion  417 . The tab portion and the two leg portions each, respectively, have a debossed bump  450   451   452 . They are arranged co-linearly. The base and tab are connected by living hinges  445   a    445   b.  The central and distal leg portions are connected by a living hinge  447 . The distal edge of the distal leg portion is attached to the inside of the tab&#39;s U by a living hinge  448 . Another living hinge  446  connects the base to the lower part of the central leg portion. 
         [0141]    Stacked Bump—Operation 
         [0142]    As seen in  FIGS. 22A , and  22 B, to open, a finger-grip extremity of the actuator  408  is lifted from the surface of the top panel  406 . The only resistive force at that point of the operation would be a small one from bending the living hinges  445   a    445   b  between the actuator tab  441  and the actuator base  440 . This change in the actuator&#39;s configuration shortens the distance available for the leg segments. Due to the living hinge between the legs portions  447  being partially cut from the back side of the actuator, these portions hinge out toward the tear panel  407  as the actuator is raised.  FIG. 22C  shows a perspective view the can end of this version in a ready-to-open state. 
         [0143]    In  FIGS. 24A-24C  the actuator  404  is seen: in its initial position, 90-degrees up, and ready-to-open, respectively. The three bumps  450   451   452  are located on three distinct portions of the actuator and are seen stacked in  FIG. 24C , one upon the other. This occurs when the actuator has completed its translation of about 160-degrees. The bumps stacked, together constitute a foot  449 , or foot assembly. That foot is positioned over the multiplier bump  414  of the tear panel  407 . The sum of the bumps can transfer a force applied to the actuator tab  441  to the tear panel  407  and open the can. 
         [0144]    Those skilled in the art will be aware of materials, techniques and equipment suitable to produce the example embodiments presented as well as variations on the those examples. This teaching is presented for purposes of illustration and description but is not intended to be exhaustive or limiting to the forms disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments and versions help to explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand it. Various embodiments with various modifications as are suited to the particular use contemplated are expected. 
         [0145]    In the following claims, the words “a” and “an” should be taken to mean “at least one” in all cases, even if the wording “at least one” appears in one or more claims explicitly. The scope of the invention is set out in the claims below.