Abstract:
A container which has a top with two concentrically mounted lids, a first lid attached to and sealing the container and a second lid rotatably mounted to the first lid. The first lid has a weakened surface region formed by scoring, scribing or grooving. The first and second lids have nested embossments which are interengageable to apply a predetermined pressure to fracture the weakened region and form a pour aperture in the first lid when the second lid is rotated relative to the first lid. The second lid also has an aperture which is brought into an overlying relationship with the aperture in the first lid when the second lid is rotated relative to the first lid, thus allowing the contents of the container to be dispensed.

Description:
FIELD OF THE INVENTION 
     This invention relates to containers, and especially to beverage cans with easy-open and reseal features. 
     BACKGROUND OF THE INVENTION 
     Sealed containers with easy-open features are used extensively to market various products such as beverages or other liquids, as well as solids in granular form. A typical example of such a container is provided by an aluminum beverage can. This container provides an air-tight seal for storing carbonated beverages and can be opened relatively easily without the use of a separate tool, such as a can opener. The top of the container has an integral, roughly oval tab defined by a score line cut in the top and a ring attached to the tab. The tab and ring work in conjunction such that lifting the ring exerts a prying force on the tab which fractures at the score line. The tab separates from the top along the score line and is forced downwardly into the container forming a pour opening for dispensing the contents of the container. The tab and ring combination desirably remain attached to the container. 
     There are several disadvantages to the ring-tab container design. Once opened, the ring tab cannot be used to close the aperture in the container. Unless consumed promptly, carbonated beverages rapidly lose carbonation, and if left untended, the further problem of inadvertent spillage exists. Still another problem is that people troubled by physical problems, such as arthritis, frequently find it difficult to grasp the ring to apply the force and to exert sufficient prying action to fracture the tab score line. This problem is sufficiently great that a special can opener has been marketed for use with ring-tab cans, which gives the user added leverage when opening the sealed tab. The need for a special tool entirely defeats the object of the tab-ring design. Sometimes the ring breaks free from the tab without opening the container. Perhaps the objectionable feature for many consumers is that the entire surface of the top is subject to exposure to dirt and other contaminants. These contaminants are introduced directly into the container contents by the action of the tab-ring design because the tab is forced into the container when the container is opened. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     This invention provides a container for beverages or the like having a top comprising a pair of lids which are stacked and relatively movable to effect opening and closure. 
     The container has a first or inner lid which is attached to the sidewalls by means similar to those utilized with present containers. The first lid is substantially planar with an eccentrically disposed, raised surface portion or embossment, referred to as an emboss by those in the art. The raised surface portion is substantially surrounded by a narrow weakened region formed by scoring or scribing or the like. The residual left following scoring is strong enough to withstand the internal pressures likely to be encountered with the particular beverage the container is intended to hold but will fracture to form a pour opening upon application of a predetermined downward external pressure, as will be explained hereinafter. The weakened region is preferably surrounded by a first sealing surface portion. 
     A second lid is rotatably attached to the container on the outside of the first lid. The second lid has an aperture or pour opening and an emboss which nests over the emboss of the first lid and having a sloping wall portion which is in mating relationship with a sloping wall portion of the emboss on the first lid. The second lid preferably has a reinforcing rib surrounding its emboss and a sealing surface portion which extends around the emboss on the first lid and interfaces with the first sealing surface. 
     Upon rotation of the second lid relative to the first lid, the sloping surface of the emboss on the second lid cams the sloping surface of the emboss on the first lid to effect a fracture at the score line. Further rotation of the second lid relative to the first lid forces the raised surface portion downwardly into the container, forming the pour aperture in the first lid. The rotation of the second lid relative to the first lid also brings the apertures in the first and second lids into an overlying relationship, allowing the container contents to be dispensed. 
     In a preferred embodiment of the invention, the container pour aperture can be reclosed upon reversing the rotation of the second lid relative to the first lid so that the pour aperture is covered by the lid stock of the first lid. Desirably, the surface portions on each lid which are brought into overlying relationship by the relative rotation effect a seal which protects the contents and prolongs the carbonation, as well as to eliminate any risk of significant spillage if the opened container is left untended. 
     It is an object of the invention to provide a sealed container having a novel and improved self-contained means for opening the container, not relying in any way on the use of a ring tab or of an extrinsic tool to effect opening of the container. It is a further object of the invention to provide a container which is easy to open. A further object of the invention is to provide a container in which the easy-open feature works reliably. It is also an object to provide a container which is easy to reclose. Another object of the invention is to provide a container in which the pour aperture is protected against dirt and contamination. A more specific object of the invention is to provide a container in which the portion of the lid stock which forms the closure for the pour aperture is initially covered so that the container contents are protected from contamination when the container is opened. Other objects and advantages of the invention include the provision of a novel end closure of a container for beverages or the like which reduces risk of can end burst, which is economical to the manufacture, allows for a reduction in can end area, is easily opened and reduces the risk of injury to the consumer. These and other objects will become apparent from a consideration of the following drawings and detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the detailed description of a preferred embodiment of the invention, reference is made to the following drawings in which: 
     FIG. 1 is an isometric view of a container according to the invention; 
     FIG. 2 is an isometric and exploded view of the upper portion of the container of FIG. 1 viewing the first lid from above and the second lid from below; 
     FIG. 3 is a sectional view of the container sidewall and top taken on line 3--3 of FIG. 1 showing the top with first and second lids in the initial sealed configuration; 
     FIG. 4 is a sectional view of the container side wall and top taken on line 3--3 of FIG. 1 showing the second lid partially rotated relative to the first lid; 
     FIG. 5 is a sectional view of the container sidewall and top taken on line 3--3 of FIG. 1 showing the full rotation of second lid relative to the first lid to bring the apertures in both lids into registry; 
     FIG. 5a is a sectional view similar to FIG. 5 showing a modification to the aperture in the second lid; and 
     FIG. 6 is a sectional view of the container sidewall and top taken on line 3--3 of FIG. 1 showing the second lid relatively rotated back to the first position in order to effect reclosure of the dispensing aperture. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a container 10 for carbonated beverage constructed according to the invention. The body of container 10 is of conventional construction, typically being of cylindrical shape and made of a material such as an aluminum alloy. Such a container 10 has a cylindrical sidewall 12, a bottom 14 formed as a unit with the sidewall and a separate top or end closure 16 which is applied and fixed in place as a part of the container filling process. As shown in FIGS. 3-6, container 10 typically formed with a reinforced circular rim 38, shown in FIGS. 3-6, surrounding the circular opening 37. Rim 38 is formed by folding the free edge of the container sidewall 12 through 180° inwardly against itself around the entire circumference of circular opening 37, thus forming an extended inner rim wall 35 and an extended outer rim wall 33. An annular indentation 40 is located adjacent to rim 38, indentation 40 being preferably formed by the sidewall 12 curving inwardly to a smaller cylinder diameter 41 and outwardly to a larger cylinder diameter 43 for reasons which will be explained below. 
     In carrying out the invention, container end closure or top 16 is comprised of a first lid 18 and a second lid 30, both shown in FIG. 2 which is an exploded view of the upper portion of the container. The first and second lids are preferably substantially planar and circular and formed in forming dies from aluminum alloy stock typically having a thickness of about 0.009 inches. First lid 18 has a first lid flange 42, preferably continuous and disposed around its circumference which fits over rim 38, as shown in FIGS. 2 and also in section in FIGS. 3-6. First lid 18 also has a first lid circumferential edge 44, preferably continuous, forming the outermost edge of first lid flange 42. 
     First lid 18 is joined to sidewall 12 at circular opening 37, using known techniques, by bending first lid flange 42 so that it is press fitted over rim 38. Preferably, the circumferential edge 44 is bent inwardly such that it fits under annular indentation 40, shown in FIGS. 3-6. 
     Second lid 30, concentrically disposed on first lid 18, has a circumferentially extending lid flange 50 which fits over flange 42 of the first lid and is relatively rotatable with respect thereto. A circumferential edge 52 on second lid 30 is bent inwardly to rest within the annular indentation 40. The inwardly bent flange edge bears against the circumferential edge 44 so as to serve as a retainer for the first lid. 
     First lid 18 further has a raised portion or emboss 20, eccentrically located, preferably circular and with sloping sidewalls substantially surrounded by a relatively narrow weakened region or score line 22 typically formed by scoring, scribing or stamping. Score line 22 is designed to fracture and form a first lid aperture 54, shown in FIGS. 4-6, when a predetermined pressure is applied to the raised portion or emboss 20. 
     Second lid 30 preferably is provided with a second emboss or raised surface portion 31, eccentrically located, so that in an initial position, it snuggly nests over first emboss 20, as can be seen best in FIGS. 3-6. Reinforcing ribs 21 and 21a surround emboss 22 to serve as stiffeners for the lid stock in the region of the emboss. When the second lid 30 is rotated relative to the first lid 18, preferably clockwise, a sloped sidewall 32 on emboss 31 contacts the sloped sidewall of emboss 20, applying the predetermined camming pressure to cause score line 22 to fracture, as shown at 56 in FIG. 4. As seen in FIG. 4, the raised surface emboss 20 is forced downwardly into container 10 as the second lid 30 is rotated relative to the first lid 18. 
     Score line 22 preferably has a relatively deep region 24 at the point where surface portion 32 initially contacts surface portion 20 so that it initially fractures at this point and a relatively shallow portion 26 diametrically opposite the relatively deep region. The relatively deep portion 24 facilitates fracture initiation while the relatively shallow portion 26 serves as a hinge means which remains attached to the first lid 18 as the raised surface portion 20 is further forced downwardly by surface portion 32 as second lid 30 is further rotated relative to the first lid 18, as can be clearly seen in FIGS. 4 and 5. In carrying out the invention, in 0.009 inches lid stock, a residual of about 0.002 inches at the deepest point of the score line and about 0.003 at the shallow region has been found to be satisfactory. 
     A predetermined angle of rotation of the second lid 30 relative to the first lid 18 causes a first lid pour aperture 54 to be fully formed by fracture along score line 22 and preferably brings second lid aperture 34 into registry with the first lid aperture 54, shown in FIG. 5. Preferably, the first and second lids have cooperative means to limit the angular rotation of the second lid 30 relative to the first lid 18. The first lid has a protrusion in the form of a dimple 28 eccentrically positioned substantially diametrically opposite to the raised portion 20. The second lid has a guide recess, preferably in the form of an arcuate groove 36, eccentrically positioned on the second lid. Dimple 28 slidably fits within groove 36. Groove 36 is so positioned and dimensioned relative to dimple 28, surface portion 32 and second lid aperture 34 so that the dimple 28 is at the end of groove 36 when the second lid 30 is rotated through the predetermined angle of rotation relative to the first lid 18. As a result of the motion, the surface portion 32 cams emboss 20 downwardly initiating fracture of score line 22 at its relatively deep region 24, then forcing emboss 20 downwardly into container 10 forming the first lid pour aperture 54. The rotation of the second lid to the extreme limit permitted by groove 36 finally brings the second lid aperture 34 into registry with the first lid aperture 54. 
     As a means of eliminating the risk of cuts sometimes occurring with the apertures in the lids of conventional tab opening cans, the edges of aperture 34 may be extended inwardly to form a downturned guard lip, shown at 34a in FIG. 5a. When the two apertures are in registry, as illustrated in the modification of FIG. 5a, the lip 34a fits over the edges of aperture 54. 
     The first and second lids further cooperate to seal container 10 after opening. A first lid sealing surface portion 58 immediately surrounds score line 22 and cooperates with second lid sealing surface 60 disposed adjacent to second lid aperture 34. When the second lid 30 is rotated from the position where the second lid aperture 34 is in registry with the first lid aperture 54 to the position where the second lid aperture 34 is not overlapping the first lid aperture 54, the second lid sealing surface portion 60 interfaces with the first lid sealing surface portion 58, as shown in FIG. 6. Substantially the same predetermined relative angular rotation required to bring the lid apertures into registry is required to bring the surface sealing portions into registry. This relative angular rotation is opposite in direction to the rotation which brings the lid apertures into registry. The relative angular rotation is preferably limited in both instances by the protrusion 28 traversing the groove 36. 
     In summary, the invention offer significant advantages over present tab opening can designs. 
     The two embosses nested one within the other effectively protect the aperture forming area of first lid from contaminants and from damage, reducing the risk of can end burst. The nested embosses contribute to facilitate easy fracture at the score line due to the camming action of the sloping sidewalls of the nested embosses. The twist-open lid is appreciably easier to open by those with arthritis and other joint diseases. Elimination of the need for a pull tab as used on conventional beverage cans eliminates a constant tooling maintenance problem, reduces production costs and avoids the troublesome problems of tab breakage. Carbonation of beverages in opened cans can be prolonged due to the ability to close the pour aperture. The diameter of the can end may be reduced as compared to conventional tab opening cans without appreciably affecting the ease with which the can is able to be opened, thereby further increasing resistance to can end burst.