Abstract:
Combination flex and torsion springs for use with light weight covers for containers having self-closing gates, the springs operatively connecting the gates to surrounding cover portions. A tri-fold seam including a frangible seam works cooperatively with the flex-torsion springs to implement three modes of operation of the gates. In a first mode, the gate returns to a reclosed orientation after removal of downward pressure. Further pressure on the gate engages a toggle operation that locks the gate open. In a third mode, if the gate is pushed even further downward, the toggle mechanism is defeated and the combination flex-torsion spring is forced past its elastic limit and the gate remains in a permanently open orientation. The flex-torsion springs in accordance with the invention may be fabricated from aluminum sheet stock or spring wire.

Description:
RELATED APPLICATIONS 
       [0001]    This application is related to U.S. patent application Ser. No. 13/477,984 for RESEALABLE CONTAINER HAVING FRANGIBLE PORTION AND HINGED TOP filed May 22, 2012 that was in turn a continuation-in-part of the U.S. patent application Ser. No. 12/195,372 for LIGHT WEIGHT HINGED TOP filed Aug. 20, 2008, now issued as U.S. Pat. No. 8,215,513. Both applications and the issued patent are included herein in their entirety by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention pertains to container tops and, more particularly, to a light weight top with a frangible, self-closing gate that occupies a large percentage of the area of the container top supported by a combination flex and torsion spring. 
       BACKGROUND OF THE INVENTION 
       [0003]    For many years, manufacturers of cans, particularly aluminum beverage containers have searched for a way to replace pull tab opening mechanisms universally used in the beverage industry. Variations of pull tab opening mechanisms are universally used throughout the world but have two primary deficiencies. First, with some pull tab designs, the tab may fall into the beverage container and potentially become a swallowing hazard. Second, once opened, pull tab opening mechanisms are not easily resealed. Beverages, particularly carbonated beverages like beer and soft drinks rapidly lose their effervescence as the entrained carbon dioxide is released from the beverage and passes into the air surrounding the beverage container. 
         [0004]    Additionally, pull tab opening mechanisms typically require at least some finger/hand strength to open the container. The opening process may present difficulties to potential users who do not possess sufficient finger/hand strength. 
         [0005]    Also, pull tab tops of the prior art require a quantity of metal, generally aluminum, that might be reduced in a better design, and are process intensive in their manufacture. 
         [0006]    In the previously filed included by reference applications, covers having relatively small self-closing gate openings have been disclosed. The beverage industry, in particular, is clamoring for containers having self-closing covers but having larger openings. No such container covers have heretofore been available. 
         [0007]    It would, therefore, be desirable to create an easily openable container cover that eliminates the possibility of any portion of the pull tab opening mechanism from detaching from the can and falling into the contents and, in addition, it would be desirable to create a self-closing cover so as to trap carbon dioxide from escaping from the beverage into the surrounding air. It would further be desirable to make the container top light weight to minimize the amount of metal needed to form the top. It would be further desirable to provide self-closing covers having openable gates occupying up to 100% of the surface area including the chuck walls of the container top. 
       SUMMARY OF THE INVENTION 
       [0008]    In accordance with the present invention there are provided light weight, covers for containers having reclosable gate or dome areas that are operatively connected to outer portions of the cover by a combination flex-torsion spring. A unique tri-fold seam including a frangible seam portion forms an inverted flange that works cooperatively with the combination flex-torsion spring to implement three modes of operation of the openable gates. In a first mode, after the gate is initially opened by downward directed pressure, for example a tap on the dome or gate by the heal of the palm of a user&#39;s hand, the gate returns to a reclosed orientation. Further downward pressure on the gate pushes it further into the container to which the novel cover is attached whereat a toggle operation locks the gate in the open position. An action such as swirling the container contents against the gate, overcome the toggle and the gate again returns to a reclosed orientation. Finally, if the gate is pushed even further downward, the toggle mechanism is defeated and the combination flex-torsion spring is forced past its elastic limit and the gate remains in a permanently open orientation. The novel covers in accordance with the invention may be fabricated to be compatible with current production equipment and practices. The novel covers eliminate the pull tab construction of the prior art and allow comparable containers to be produced using less material than prior art containers. Multiple designs for combination flex-torsion springs are also provided, including extremely narrow designs that allow the gate to occupy nearly 100% of the cover area inside or outside the chuck walls. 
         [0009]    It is, therefore, an object of the invention to provide a lightweight, self-closing cover for a container. 
         [0010]    It is another object of the invention to provide a lightweight, self-closing cover for a container that utilizes a flex-torsion spring to effect reclosing. 
         [0011]    It is an additional object of the invention to provide a lightweight, self-closing cover for a container that utilizes a flex-torsion spring to provide three modes of operation of the gate: a first mode allowing the gate to close upon release of the downward pressure upon it; a second mode wherein the gate remains open when the downward pressure is released but recloses when tapped or otherwise stimulated; and a third mode where the gate remains permanently open. 
         [0012]    It is a further object of the invention to provide a lightweight, self-closing top for a container wherein the gate occupies up to 100% of the cover area inside or outside the chuck walls. 
         [0013]    It is a still further object of the invention to provide a lightweight, self-closing top for a container that may be formed using smaller amounts of aluminum or other material than container covers of the prior art. 
         [0014]    It is yet another object of the invention to provide a lightweight, self-closing top for a container that may be attached to containers using existing machinery without modification. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    Various objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
           [0016]      FIG. 1A  is a side elevational, cross-sectional, schematic view of a light weight, hinged self-closing container cover having a combination flex and torsion spring in a closed configuration in accordance with the invention; 
           [0017]      FIGS. 1B and 1C  are enlarged portions of the light weight, hinged self-closing container cover having a combination flex and torsion spring of  FIG. 1A ; 
           [0018]      FIG. 1D  is another enlarged portion of the light weight, hinged self-closing container cover of  FIG. 1C  before separation; 
           [0019]      FIG. 1E  is another enlarged portion of the light weight, hinged self-closing container cover of  FIG. 1C  as separation begins; 
           [0020]      FIG. 1F  is a bottom plan view of the cover of  FIG. 1A  showing the location of the hinged spring; 
           [0021]      FIG. 2  is a side elevational, cross-sectional, perspective, schematic view of the light weight, hinged self-closing container cover having a combination flex and torsion spring of  FIG. 1A ; 
           [0022]      FIGS. 3A and 3B  are top and bottom perspective, schematic views of combination flex and torsion spring attached to cover of  FIG. 1A ; 
           [0023]      FIG. 4A  is a bottom plan, schematic view of a hypothetical container top having a gate and six beaks equidistantly spaced along a frangible seam; 
           [0024]      FIGS. 4B-4I  are side elevational, cross-sectional, schematic views of a simplified light weight, hinged, self-closing container cover of  FIG. 1A  in various stages of opening and reclosing; 
           [0025]      FIG. 4J  is an enlarged portion of the cover of  FIG. 4D  showing the interaction of the combination flex and torsion spring and showing a flange formed by the tri-fold seam; 
           [0026]      FIG. 4K  is a partial side elevational, cross-sectional view of a portion of the cover of  FIG. 4   a  showing a detailed schematic view of one of the breaks; 
           [0027]      FIG. 5A  is a top plan, schematic view of a container cover having a large (approximately 90% or larger) gate 
           [0028]      FIG. 5B  is a partial side elevational, cross-sectional view of the cover of  FIG. 5A ; 
           [0029]      FIG. 5C  is an enlarged portion of the view of  FIG. 5B  showing a detailed view of the triple fold flange showing the frangible seam/tear line; 
           [0030]      FIG. 5D  is a partial side elevational, cross-sectional view of the cover of  FIG. 5A  showing a triple fold seam contained within a chuck wall, and with a closed gate; 
           [0031]      FIG. 5E  is a partial side elevational, cross-sectional view of the cover of 
           [0032]      FIG. 5D  showing a triple fold seam contained within a chuck wall and with a gate partially open; 
           [0033]      FIG. 5F  is a partial side elevational, cross-sectional view of the cover of  FIG. 5D  showing a triple fold seam contained within a chuck wall and with a gate fully open; 
           [0034]      FIG. 6A  is a bottom perspective, schematic view of a first embodiment of a combination flex-torsion spring for use in conjunction with the cover of  FIG. 5A ; 
           [0035]      FIG. 6B  is a bottom plan view of the cover of  FIG. 5A  with the combination flex-torsion spring of  FIG. 6A  coupled thereto; 
           [0036]      FIG. 7A  is a bottom perspective, schematic view of an alternate embodiment of a combination flex-torsion spring for use in conjunction with the cover of  FIG. 5A ; 
           [0037]      FIG. 7B  is a bottom plan view of the cover of  FIG. 5A  with the combination flex-torsion spring of  FIG. 7A  coupled thereto; 
           [0038]      FIG. 8  is a bottom perspective view of a combination flex-torsion spring formed having the same general shape as the spring of  FIG. 7A  but formed from spring wire; 
           [0039]      FIG. 9A  is a top perspective, schematic view of another implementation of a combination flex-torsion spring intended for use with smaller gates; and 
           [0040]      FIG. 9B  is a bottom plan, schematic view of a cover utilizing the combination flex-torsion spring of  FIG. 9A . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0041]    The present invention provides light weight, hinged, self-closing container covers having combination flex and torsion (flex-torsion) springs. Flex-torsion springs exhibit two modes of operation: that of a traditional flex spring combined with that of a traditional torsion spring. While applicable to many different sizes and styles of container, the novel cover of the present invention is particularly useful for beverage containers. In addition, multiple combination flex-torsion spring designs are provided. 
         [0042]    In my previous work, light weight, self-closing covers having several sizes and configurations were disclosed. However, none of the previously disclosed designs allowed for large gate openings, for example, gate openings that covered 90% or more of the cover real estate within or including the outer chuck walls. 
         [0043]    Every self-closing cover requires a spring to provide a restoring force to close the gate once the gate has been opened. In the previously disclosed designs, springs having only a flexing mode of operation have been utilized. These types of spring typically occupy too much space to allow practical covers having self-closing, large gate openings to be constructed. As used herein, the term large gate openings is used to refer to gate openings of approximately 90% or more of the surface area of the cover included within the chuck walls or, in some cases, including the chuck walls. 
         [0044]    However, it should be noted that gate sizes even larger than 90% are possible by careful spring design and integrating at least a portion of the spring inside the raised (or depressed) ridge that is a chuck wall. Such designs are referred to as “inside a chuck wall”. The term “within the chuck walls” refers to designs where the spring and associated mechansims are located within the cover space defined by the perimeter chuck wall but NOT physically inside a chuck wall. 
         [0045]    Flex springs generate their restorative force by merely moving in a single plane. A force applied to a flex spring pushes it from an original position to a new position. Assuming that the spring has not been pushed beyond its elastic limit and deformed, once the force is released, the spring attempts to return to its original position and in the process, provides a restorative force. The size of the flex spring and the material from which it is made determines the amount of restorative force that the spring can generate. 
         [0046]    Spring designs that generate restoring forces from more than one modality of operation, for example, the flex-torsion spring used in the designs of the present invention may be constructed more compactly. In such designs, only a portion of the restoring force is derived from the flexing action of the spring. Another portion of the necessary restoring force is derived from the twisting/untwisting motion of a torsion component of the flex-torsion spring. Consequently, springs having compact flex portions and thin, curved elongated arms extending outwardly from the central or flex portion of the flex-torsion spring may be constructed. The thin, curved elongated arms that may move with a twisting motion may provide a large portion of the restoring force necessary to close, for example, the gate of a large gate self-closing cover. 
         [0047]    Referring first to  FIG. 1A , there is shown a side elevational, cross-sectional, schematic view of a simplified light weight, hinged, self-closing container cover having a combination torsion and flex spring, generally at reference number  100 . Cover  100  is shown before attachment to a container, not shown, and in a sealed (i.e., unopened) state. Further, cover  100  is a simplified design used to illustrate the operation of the combination flex and torsion spring. More complex covers using combination flex and torsion springs are described and discussed hereinbelow. 
         [0048]    Cover  100  consists of a seaming panel (shown as seaming panel segments  102   a,    102   b  having respective distal ends  104   a,    104   b  forming a so-called curl. Distal ends  104   a,    104   b  are adapted for attachment to upstanding walls  118   a,    118   b  ( FIG. 4B ) of a container, not shown, thereby forming a peripheral seam or seal, not specifically identified. 
         [0049]    It should be noted that any container discussed or shown forms no part of the present invention and such containers when shown and/or discussed are presented only to better describe cover  100 . 
         [0050]    Intermediate sloping panel segments  134   a,    134   b  connect seaming panel segments  102   a,    102   b  to outer countersink walls  114   a,    114   b.  Countersinks  116   a,    116   b  are formed by outer countersink walls  114   a,  connected to respective countersink inner walls  114   b.    
         [0051]    Inner countersink walls  114   b  connect to respective top panel portions  136   a,    136   b  that, in turn, connect to respective triple fold seams  106   a,    106   b.    
         [0052]    A Triple fold seam  112  surrounds a central gate or dome  108 . 
         [0053]    While in the cross-sectional view of  FIG. 1A , seaming panel portions  102   a,    102   b,  distal ends  104   a,    104   b,  intermediate sloping sections  134   a,    134   b,  and top panel portions  136   a.    136   b  are labeled for purposes of discussion, cover  100  is typically a circular structure and seaming panel  102  represented as seaming panel portions  102   a,    102   b,  etc. are in reality, continuous circular structures best seen in  FIG. 2  until gate  108  is opened. 
         [0054]    Flanges  106   a,    106   b  are shown in more detail in  FIGS. 1B and 1C , respectively, and are discussed in more detail hereinbelow. 
         [0055]    While gate  108  is shown as a substantially flat surface, it will be recognized that gate  108  may be replaced by an upwardly (or in alternate embodiments, downwardly directed) curvilinear structure as shown in alternate gate or dome  108 ′. 
         [0056]    A combination flex-torsion spring  112  provides support and closure force for gate  108  after the gate has been opened. 
         [0057]    Flex-torsion spring  112  is typically formed from aluminum, often the same material from which the remainder of cover  100  and the container are formed. A typical aluminum alloy found suitable for the application is 5052-H19 and a thickness in the range of approximately 0.006 to 0.007 inch. It will be recognized that other aluminum alloys and/or material thicknesses may be substituted to meet particular operating circumstance or design. Consequently, the invention is not considered limited the alloy or thickness range chosen for purposes of disclosure. Rather, the invention is intended to include other metals, alloys, and/or thicknesses. 
         [0058]    Referring now also to  FIGS. 1B and 1C , there are shown enlarged drawings of portions of triple fold flanges  106   a,    106   b,  respectively. Of particular interest is the coined frangible seam  110   a,    110   b  formed in respective flanges  106   a,    106   b.  Frangible seam  110   a,    110   b  defines a tear line completely around gate  108  that allows separation of gate  108  from panel  102  as gate  108  of cover  100  is “opened”. While frangible seams  110   a,    110   b  are typically formed using a coining process, it will be recognized by those of skill in the art that alternate formation processes may be utilized. The opening process is discussed in more detail hereinbelow. 
         [0059]    It will be recognized that the concept of “beaks” has been discussed extensively in my forgoing work, U.S. Pat. No. 8,215,513, included herein by reference. Beaks, so named for their tapered, pointed shape, or other similar structures, none shown, are provided at one or more points along the frangible seam  110   a,    110   b  to facilitate an initial rupture of the frangible seam. Providing beaks or similar structures reduces the applied force required to open the container by separating the frangible seam (i.e., the tear line). With larger, round gate in accordance with the present invention, the necessity for more than two beaks is envisioned. A preliminary analysis indicates that five to seven beaks disposed circumferentially around large round gates proximate the frangible seam may be required to ensure proper opening, 
         [0060]    Referring now also to  FIG. 1D , there is shown an additional cross-sectional, schematic view of the seam of  FIG. 1C . Frangible seam  110   b  is thinned adjacent curved structures  150   a,    150 B forming an indentation  152  in frangible seam  110   b.  As depicted in  FIG. 1D , frangible seam  110   b  has not yet begun to rupture. 
         [0061]    Referring now also to  FIG. 1E , there is shown an additional cross-sectional, schematic view of the seam of  FIG. 1C  but showing that frangible seam  110   b  has begun to rupture adjacent curved structures  150   a,    150   b.  Portions  154   a,    154   b  are shown separated with respect to one another. 
         [0062]    Referring now also to  FIG. 1F , there is shown a bottom plan, schematic view of cover  100 . Notable in  FIG. 1F  are optional fasteners or stakes  144  and  146 . First and second optional fasteners or stakes  144  attach opposing arcuate side arms  126   a,    126   b  to gate  108  through a corresponding one of optional holes  130   a,    130   b.  Another optional fastener or stake  146  through hole  122  in central portion  120  not shown fastens spring  112  to panel  136 . Holes  130   a,    130   b,  and  122  are best seen in  FIGS. 3A and 3B . 
         [0063]    Referring now also to  FIG. 2 , there is shown a side elevational, cross-sectional, perspective, schematic view of the simplified light weight, hinged self-closing container cover having a combination flex-torsion spring  112  of  FIG. 1A . In  FIG. 2 , the relationship of combination flex-torsion spring  112  to the panel  136  and the gate  108  is better illustrated. 
         [0064]    Referring now also to  FIGS. 3A and 3B , there are shown top and bottom perspective, schematic views of combination flex-torsion spring  112 . 
         [0065]    Spring  112  has a substantially flat square central portion  120 , typically having a central hole  122  therethrough. Central portion  120  has an inward facing camming detent structure  124  disposed on a front edge, not identified, perpendicular to the flat surface, not identified, of central portion  120 . Inward facing refers to the direction toward the center of cover  100 . The functions of camming detent structure  124  are discussed in more detail hereinbelow. 
         [0066]    A pair of opposing arcuate side arms  126   a,    126   b  project outward from respective sides of the flat portion of central portion  120 . Opposing arcuate side arms  126   a,    126   b  have a short curved section  132   a,    132   b,  respectively, adjacent central portion  120  that allows the major surface of each to be raised to approximately the same height as that of camming detent structure  124 . 
         [0067]    Each of opposing arcuate side arms  126   a,    126   b  has a flattened portion  128   a,    128   b  adjacent their respective distal ends, not specifically identified. Flattened portions  128   a,    128   b  may be off-set or stepped up or down to a different plane from the remainder of side arms  126   a  and  126   b.  An optional through hole  130   a,    130   b  may be centrally located in respective flattened portions  128   a,    128   b.    
         [0068]    Referring now also to  FIG. 4A , there is shown a bottom plan, schematic view of a hypothetical container top having a gate  108  with six beaks  158  equidistantly spaced around a frangible seam  110  separating gate  108  from an adjacent panel  136  at locations  156 . As may be seen in  FIG. 4K , frangible seam  110  is surrounded by weakened areas  148 . 
         [0069]      FIG. 4K  is a partial side elevational, cross-sectional view of a portion of the cover of  FIG. 4   a  showing a detailed schematic view of one of the breaks  158  shown in  FIG. 4A  at locations  156  around the perimeter of gate  108 . In  FIG. 4A , frangible seam or tear line  110  is surrounded on each side by two weakened areas  148  along curved areas adjacent  156 ; 
         [0070]    As mentioned, beak structures having many different shapes, sizes, and dispositions capable of facilitating an initial rupture of frangible seam  110  will be recognized by those of skill in the art. Consequently, the invention is not considered limited to any particular quantity of a particular shape, size, and orientation of a beak structure. The invention is intended to include any and all suitable replacement structures for the beaks disclosed in the included by reference &#39;513 patent. 
         [0071]    With larger, especially round gates in accordance with the invention, the downwardly directed opening force applied to gate  108  may strike gate  108  in a number of different spots. The number of beak locations  156  (six in the example chosen for purposes of disclosure) allows the rupture of frangible seam  110  to start proximate the beak  158  nearest the point of impact. This helps maintain a need for a substantially uniform downwardly directed force, regardless of where on the gate  108  that force is applied. The rupture of frangible seam  110  typically proceeds both clockwise and counterclockwise from the point of initial rupture at or near one of beaks  158  until the entire frangible seam  110  has ruptured. 
         [0072]      FIGS. 1A and 2  show cover  100  in an unopened condition. Referring now to  FIGS. 4B-4I , there are shown a series of side elevational, cross-sectional, schematic views of the simplified light weight, hinged, self-closing container cover  100  of  FIG. 1A  illustrating steps of the initial opening and self-closing of cover  100 . Note that container sides  118   a,    118   b  are partially shown in  FIG. 4B . As previously stated, container walls  118   a,    118   b  form no part of the present invention. 
         [0073]    In operation, cover  100  is first opened by a downward pressure on gate  108  as indicated by arrow  140 . As previously discussed, typically downward pressure is supplied by the heal of a hand of a person, not shown, opening the container. In  FIG. 4B  it may readily be seen that frangible seam  110   a  has started to rupture at a point shown by arrow  160  in response to downward force indicated by arrow  140 . Note that frangible seam  110   b  is as yet unaffected by the downward pressure indicated by arrow  140 . 
         [0074]    In  FIG. 4C , the rupture of frangible seam  110   a  continues and the left edge of gate  108  has moved further inward into the container represented by container side walls  118   a,    118   b.  Note that frangible seam  110   b  is still unaffected by the downward pressure indicated by arrow  140 . 
         [0075]    In  FIG. 4D , the rupture of frangible seam  110   a  continues and the left edge of gate  108  has moved still further inward into the container represented by container side walls  118   a,    118   b.  Note that frangible seam  110   b  is still unaffected by the downward pressure indicated by arrow  140 . 
         [0076]    In  FIG. 4E , frangible seam  110   b  has finally ruptured at a position shown by arrow  162  and the left edge of gate  108  begins to rise upward, pivoting on heal of the palm of the person opening the container in response to a restoring force provided by flex-torsion spring  112 . The gap in frangible seam  110   a  has begun to close. 
         [0077]    In  FIG. 4F , the gap at location  162  continues to widen in response to continued downward force and the left edge of gate  108  continues to rise in response to a restoring force provided by flex-torsion spring  112 . The gap in frangible seam  110   a  continues to close. 
         [0078]    In  FIG. 4G , frangible seam  110   a  returns to an original position as shown by arrow  164 . 
         [0079]    In  FIG. 4H , downward pressure shown at arrow  140  is removed and an upward (i.e., restoring force) supplied by flex-torsion spring  112  moves the right edge of gate  108  upwards in a direction shown by arrow  166 . 
         [0080]    Finally in  FIG. 4I , the gate  108  is returned to a position similar to its unopened position ( FIG. 1A ) and the gate effectively reseals the container cover  100 . 
         [0081]    Referring now also to  FIG. 4J , once curved portion  148  is engaged in camming detent structure  124 , gate  108  is permanently held in that open position, sometimes referred to as toggle mode. 
         [0082]    It is possible using the design principles illustrated hereinabove to construct container covers wherein the gate covers substantially 100% (i.e., 90% or higher) of the area of the container within or including the chuck walls. Referring now also to  FIG. 5A , there is shown a top plan, schematic view of a cover having a large gate, generally at reference number  200 . 
         [0083]    Cover  200  has a central gate  204  having a width shown by arrow  206 . Gate  204  is surrounded by a triple fold (i.e., tri-fold) seam  210 . A panel  216  surrounds triple fold seam  210  and panel  216  is surrounded by countersink  218 . A peripheral seam, not shown, is formed adjacent and/or including a curl  208  when cover  200  is attached to a container body, not shown. 
         [0084]    Referring now also to  FIG. 5B , there is shown a partial side elevational, cross-sectional view of the cover  200  of  FIG. 5A  wherein triple fold flange or seam  212  is contained within triple fold seam  210 , an enlarged detail of triple seam or flange  210  is shown in  FIG. 5C . 
         [0085]    Referring now also to  FIGS. 5D ,  5 E, and  5 F there are shown partial side elevational, cross-sectional views of the cover of  FIG. 5A  wherein a triple fold flange  210  is contained inside the chuck wall perimeter defined by countersink  218 , and gate  204  is shown closed, partially open, and fully open, respectively. 
         [0086]    Because of the extremely limited space imposed by a “large” gate (e.g., approximately 90% or more), spring design becomes critical. The combination flex-torsion springs for use in these designs have many constraints on their size. Nonetheless, such springs still need to perform the necessary different reclosure functions. 
         [0087]    Referring now also to  FIG. 6A , there is shown a bottom perspective, schematic view of a design for a combination flex-torsion spring suitable for use with a large gate, self-closing cover, generally at reference number  220 . 
         [0088]    Combination flex-torsion spring  220  has a central portion  222 . Central portion  222  has a rear curved portion  224  adapted to conform to the curvature of tri-fold flange  210  and a front flat portion  226 . A through hole  228  is placed in front, flat portion  226 . 
         [0089]    One of a pair of opposing arcuate side arms  230   a,    230   b  extends from each edge of central portion  222 . Each of opposing arcuate side arms  230   a,    230   b  has a flattened region  232   a,    232   b,  respectively, at the distal ends thereof. Each flattened region  232   a,    232   b  has an elongated through hole  234   a,    234   b,  respectively. 
         [0090]    One of a pair of toggle tabs  236   a,    236   b  extend upward from respective ones of the pair of opposing arcuate side arms  230   a,    230   b.  Toggle tabs  236   a,    236   b  are disposed approximately half way along a respective one of opposing arcuate side arms  230   a,    230   b.    
         [0091]    Referring now also to  FIG. 6B , there is shown a bottom plan view of the cover  200  of  FIG. 5A  with the combination flex-torsion spring  220  of  FIG. 6A  coupled thereto. A fastener or stake, not shown, may be placed in through hole  228  and through the gate  204 . The fastener or stake is used to ensure proper registration of combination flex-torsion spring  220  during its attachment to cover  200  during the manufacturing of cover  200 . 
         [0092]    Adhesive  238  proximate each of through holes  234   a,    234   b  is used to fasten flattened tip regions  232   a,    232   b  to seaming panel, not specifically identified. Unlike the embodiment shown in  FIGS. 5A-5F  using a combination flex-torsion spring, for example, spring  112  of  FIGS. 3A and 3B , there is no space to use a mechanical fastener or stake to attach flattened tip regions  232   a,    232   b  to panel  210 . Consequently, adhesive or a similar fastening system must be used to replace fasteners or stakes  144  ( FIG. 1F ). Optional holes  234   a,    234   b  allow any excess adhesive  238  placed under flattened tip regions  232   a,    232   b  to escape through the holes  234   a,    234   b.  In addition, holes  234   a,    234   b  may be used as a port to allow UV curing energy to reach the adhesive. Any suitable adhesive may be utilized in addition to UV-curable adhesives. 
         [0093]    In operation, cover  200  is opened by a directed downward pressure on gate  204  as shown by arrow  140  typically applied at or near the center of gate  108 . Upon application of directed downward pressure, frangible seam  212  ruptures, thereby allowing gate  204  to rotate downward into an interior region of the container, not specifically identified and forming no part of the invention, to which cover  200  is attached. Rotation of gate  204  must overcome the elastic resistive force provided by flex-torsion spring  220 . The resilient force of the combination flex-torsion spring  220  is provided by the flexing of the spring central portion  222  relative to the opposing arcuate side arms  230   a,    230   b.  Upon release of the directed downward pressure, the combination flex-torsion spring  220  retains sufficient memory to restore gate  204  to a closed position. Once the frangible seam  212  has been ruptured, a small amount of force is sufficient to re-open the gate  204  and access the contents. The pressure of a person&#39;s lip, not shown, against the top of the gate  204  is sufficient to re-open the gate  204  thereby allowing a user to drink from the container. 
         [0094]    Upon further application of a directed downward force, the gate  204  may be further rotated downward and toward the central portion  222  of the combination flex-torsion spring  220 . When the gate has opened through a sufficient angle with respect to the panel  202  not specifically identified, the exterior perimeter of the gate, not shown, is pushed past the tips of toggle tabs  236   a,    236   b.  Once this is accomplished, the toggle tabs  236   a,    236   b  marginally engage the upper peripheral surface of the exterior perimeter of gate  204 , and provide sufficient resistive force in opposition to the spring memory provided by the flexing of spring central portion  222 . In this position, the gate  204  is latched open, making it possible to drink from the container, or pour the contents out of the container. Subsequent closing of gate  204  may be accomplished by moving the container in a circular motion such that the interior liquid pushes against the bottom of the gate  204 , and releases the gate  204  from the marginal engagement of the toggle tabs  236   a,    236   b.    
         [0095]    Upon the application of additional force directed downward and toward the spring central portion, the gate  204  may be opened beyond the angle required to engage the toggle tabs  236   a,    236   b,  to a position that flexes the spring central portion  222  beyond its elastic limit, allowing the container to remain permanently open. 
         [0096]    Referring now also to  FIG. 7A , there is shown a bottom perspective, schematic view of an alternate design for a combination flex-torsion spring suitable for use with a large gate, self-closing cover, generally at reference number  250 . 
         [0097]    Combination flex-torsion spring  250  has an elongated central portion  252 . Central portion  252  has a rear, curved portion (i.e., flange encircling portion)  254  adapted to conform to the curvature of tri-fold flange  210 , not shown in  FIG. 7A , and a front, tongue-like flat portion  256 . A through hole  258  is placed proximate the tip of front, flat, tongue-like flat portion  256 . 
         [0098]    One of a pair of opposing arcuate side arms  260   a,    260   b  extends from each side of central portion  252 . Each of opposing arcuate side arms  260   a,    260   b  has a flattened region  262   a,    262   b,  respectively, at the distal ends thereof. Each flattened region  262   a,    262   b  has an elongated through hole  264   a,    264   b,  respectively. 
         [0099]    A pair of toggle tabs  266   a,    266   b  extends upward from respective ones of the pair of opposing arcuate side arms  260   a,    260   b.  Toggle tabs  236   a,    236   b  are disposed approximately half way along a respective one of opposing arcuate side arms  260   a,    260   b.    
         [0100]    Referring now also to  FIG. 7B , there is shown a bottom plan view of the cover  200  of  FIG. 5A  with the combination flex-torsion spring  250  of  FIG. 7A  coupled thereto. A fastener or stake  270  is placed in through hole  258  and through the gate  204 . Fastener or stake  270  is used to ensure proper registration of combination flex-torsion spring  250  during its attachment to cover  200  during the manufacturing and/or assembly of cover  200 . 
         [0101]    Adhesive  268  proximate each of elongated through holes  264   a,    264   b  is used to fasten distal ends  262   a,    262   b  to the panel  202  surrounding gate  204 . 
         [0102]    The operation of cover  200  with a combination flex-torsion spring  250  is almost identical to the operation of cover  200  equipped with combination flex-torsion spring  220  described in detail hereinabove. Consequently, the opening of cover  200  using combination flex-torsion spring  250  is not further described herein. 
         [0103]    Referring now also to  FIG. 8 , there is shown a novel implementation of combination flex-torsion spring of  250  of  FIG. 7A , generally at reference number  300 . 
         [0104]    Combination flex-torsion spring  300  is implemented by bending a length of spring wire  320  to fashion all the structural features of combination flex-torsion spring  250 . The equivalent to spring central portion  252  of spring  250  is included within the area enclosed by dashed oval  302 . 
         [0105]    Flange encircling section  254  of combination flex-torsion spring  250  is shown at reference number  304  and is implemented as curved bends  304  in spring wire  320 . 
         [0106]    Flat portion of central portion  256  of combination flex-torsion spring  250  is actually space  306  between the wire portions, not specifically identified, that connects flattened region that contains hole  308  corresponding to hole  258  of combination flex-torsion spring  250 . 
         [0107]    Opposing arcuate side arms  310   a,    310   b  are analogous to opposing arcuate side arms  260   a,    260   b  of combination flex-torsion spring  250 . 
         [0108]    Spring wire  320  may be flattened to form flattened tip regions  312   a,    312   b  that correspond to flattened tip regions  262   a,    262   b  of combination flex-torsion spring  250 . 
         [0109]    Optional elongated holes  314   a,    314   b  in flattened portions  312   a,    312   b,  respectively, correspond to elongated holes  264   a,    264   b  in combination flex-torsion spring  250 . 
         [0110]    Finally, analogous structures to toggle tabs  266   a,    266   b  are formed at regions  316   a  and  316   b  in spring wire  320 . 
         [0111]    By choosing the spring characteristics of spring wire  320 , the performance of combination flex-torsion spring  300  may match the performance of combination flex-torsion spring  250  but at a considerable savings in manufacturing cost. In use, combination flex-torsion spring  300  provides a direct “drop-in” replacement for combination flex-torsion spring  250 . 
         [0112]    Referring now also to  FIG. 9A , there is shown a top perspective, schematic view of another implementation of a wide flex spring, generally at reference number  330 . 
         [0113]    Wide flex spring  330  has a central portion  332 . A flange accepting section  334  is disposed rearward of a front tip, not specifically identified, and having a through hole  336  therein. 
         [0114]    Two slots  342   a,    342   b  separate a pair of shortened opposing arms  338   a,    338   b  from central portion  332 , 
         [0115]    A pair of toggle tabs  340   a,    340   b  is disposed on the front edges of respective ones of shortened opposing arms  338   a,    338   b.    
         [0116]    Referring now also to  FIG. 9B , there is shown a bottom plan, schematic view of a cover  346  utilizing combination flex-torsion spring  330 . 
         [0117]    Hole  336  in the tip of central portion  332  allows central portion  332  to be attached to a gate  344  by means of a fastener or stake, not shown, fastened therethrough. In alternate embodiments, an adhesive or other alternate fastening method may replace the fastener or stake to secure central portion  332  to oval, offset gate  344 . 
         [0118]    In operation, combination flex-torsion spring  330  in conjunction with cover  346  behaves very much the same as the operation of covers  200  with either spring  220  or spring  250 . This operation is described hereinabove and such operational details are not further discussed or described with regard to combination flex-torsion spring  330  and cover  346 . 
         [0119]    Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention. 
         [0120]    Having thus described the invention, what is desired to be protected by Letters Patent is presented in the subsequently appended claims.