Abstract:
A closure for a hot-filled container may have a base adapted to be coupled to the container, the base having a bottom side and a top side; and a roof having an outer diameter, the roof being coupled to the top side of the base at the outer diameter, the roof having: a plurality of substantially flat concentric panels elevated from the top side of the base, wherein each panel is elevated from the next outermost adjacent panel by a sidewall; and a substantially flat center coupled to an inner diameter of an innermost substantially flat panel and elevated therefrom.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a divisional of U.S. patent application Ser. No. 11/682,513, filed Mar. 6, 2007, now pending, which claims benefit of U.S. Provisional Application No. 60/780,055, filed Mar. 8, 2006, both of which are incorporated here by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of The Invention 
         [0003]    The present invention relates generally to container closures, and more particularly to closures for use in hot-fill containers. 
         [0004]    2. Related Art 
         [0005]    When hot-filling a container, the container is capped when the contents are at an elevated temperature. The container is manipulated to ensure the hot contents eliminate any biological contaminants in the container. At the elevated temperature, the container bulges. When the contents cool, the volume of any gas in the container is reduced, which can cause the bulging container to flex inwardly slightly past its original blown dimensions. A conventional solution to the flexing container is to put vacuum panels on the container. 
         [0006]    Vacuum panels, however, can limit design freedom for the container. For example, the positioning of vacuum panels on the label panels of the container is undesirable because there may be a gap between the label and the container where the vacuum panels are placed. If there is a gap, the label may retain water in the gap, for example, when the container is submerged in ice in a cooler. Retained water may then run out from under the label when the customer consumes the product. Additionally, the label may not be able to completely contact or adhere to the surface of the container, due to the vacuum panels&#39; deep draw characteristics into the container. 
         [0007]    Some glass beverage containers have used a metal closure to vacuum seal the containers. However, the flexing of such closures is not enough to compensate for the larger dimensional movements on larger containers. What is needed then is an improved solution to the vacuum pressure created by hot-filling that overcomes shortcomings of conventional solutions. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    Exemplary embodiments of the present invention include an expandable closure that flexes in response to pressure applied. Use of an exemplary closure may reduce or eliminate the need for vacuum panels in the body of the container, permitting more design freedom. 
         [0009]    In one exemplary embodiment, the present invention may be a closure for a hot-filled container comprising: a base adapted to be coupled to the container, the base having a bottom side and a top side; and a roof having an outer diameter, the roof being coupled to the top side of the base at the outer diameter, the roof having: a plurality of substantially flat concentric panels elevated from the top side of the base, wherein each panel is elevated from the next outermost adjacent panel by a sidewall; and a substantially flat center coupled to an inner diameter of an innermost substantially flat panel and elevated therefrom. 
         [0010]    In another exemplary embodiment, the present invention may be a closure for a hot-filled container comprising: a base adapted to be coupled to the container, the base having a bottom side and a top side; and a roof having an outer diameter, the roof being coupled to the top side of the base at the outer diameter, the roof having: at least one area of a first thickness; and at least one area of a second thickness. 
         [0011]    In another exemplary embodiment, the present invention may be a closure for a hot-filled container comprising: a base adapted to be coupled to the container, the base having a bottom side and a top side; and a roof having an outer diameter, the roof being coupled to the top side of the base at the outer diameter, the roof having: at least one area comprised of a first material; and at least one area comprised of a second material; wherein the first and second materials have different deflection rates at a given temperature. 
         [0012]    Further objectives and advantages, as well as the structure and function of preferred embodiments will become apparent from a consideration of the description, drawings, and examples. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The foregoing and other features and advantages of the invention will be apparent from the following, more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings wherein like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. 
           [0014]      FIG. 1  depicts a side view of an exemplary embodiment of an expandable closure according to the present invention; 
           [0015]      FIG. 2  depicts a top view of the closure shown in  FIG. 1 ; 
           [0016]      FIG. 3  depicts a partial cross-section of an exemplary embodiment of an expandable closure according to the present invention, wherein the roof of the closure has varying thickness; 
           [0017]      FIG. 4  depicts a partial cross-section of an exemplary embodiment of an expandable closure according to the present invention, wherein the roof of the closure has varying thickness; 
           [0018]      FIG. 5  depicts a partial cross-section of an exemplary embodiment of an expandable closure according to the present invention, wherein the roof of the closure has varying thickness; 
           [0019]      FIG. 6  depicts a partial cross-section of an exemplary embodiment of an expandable closure according to the present invention, wherein the roof of the closure has varying thickness; 
           [0020]      FIG. 7  depicts a partial cross-section of an exemplary embodiment of an expandable closure according to the present invention, wherein the roof of the closure includes at least two different materials; 
           [0021]      FIG. 8  depicts a partial cross-section of an exemplary embodiment of an expandable closure according to the present invention, wherein the roof of the closure includes at least two different materials; 
           [0022]      FIG. 9  depicts a partial cross-section of an exemplary embodiment of an expandable closure according to the present invention, wherein the roof of the closure includes at least two different materials; and 
           [0023]      FIG. 10  depicts a partial cross-section of an exemplary embodiment of an expandable closure with an over-cap according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    Embodiments of the invention are discussed in detail below. In describing embodiments, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected. While specific exemplary embodiments are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations can be used without parting from the spirit and scope of the invention. All references cited herein are incorporated by reference as if each had been individually incorporated. 
         [0025]    As seen in  FIGS. 1 and 2 , a closure  100  according to an exemplary embodiment of the present invention may have a base  102 , which may be threaded or have some other attachment mechanism for engagement with the neck of the container to be closed. Base  102  has a bottom side which is closer to the container when attached, and a top side where the “roof” of the closure is coupled. The roof of the closure may have one or more raised concentric panels  104   a,    104   b,    104   c  (collectively,  104 ). Each panel  104  is raised with respect to its outer neighbor, and lower than its inner neighbor. The amount that each panel  104  is lower with respect to its inner neighbor is determined by the height of a side wall  106   a,    106   b,    106   c,  respectively. The transition between a sidewall  106  and the panels  104  to which it is coupled may be sharp, as depicted in  FIG. 1 , or may be rounded or sloped. The closure  100  additionally has a center  108 , which has no higher inner panel, and is itself higher than its outer neighboring panel  104 . The expanded closure  100  may be substantially dome-shaped. While the closure  100  depicted in  FIGS. 1 and 2  has three panels  104  and a center, the closure  100  is not limited to only three panels and a center. More or fewer panels may be used. 
         [0026]    In other embodiments, different panels  104  are at different elevations relative to their neighboring panels. For example, panel  104   c  may be lower than panel  104   b.  Also, panels  104  may be square, oval, or some other shape, and not necessarily round. In some embodiments, the panels  104  may be of a different thickness than that of sidewalls  106 . 
         [0027]    Once a hot-filled container is closed with a closure according to an exemplary embodiment of the present invention, the closure may contract on its own as the pressure in the container falls, or the closure may be mechanically contracted with external pressure applied. When the closure  100  contracts, each panel  104  and center  106  contracts into the height of its neighboring outer panel, successively, until the closure is substantially flat-topped, or concave. 
         [0028]      FIGS. 3-6  depict partial cross-sections of exemplary closures having threads  302  and sides  304 , where the thickness of the tops ( 306 ,  406 ,  506 , and  606 , respectively) of the closures is varied to allow the closure to flex in response to pressure. The closures may flex, for example, where the material is thinner than the surrounding material. 
         [0029]      FIGS. 7-9  depict partial cross-sections of exemplary closures having threads  302  and sides  304 , where the tops ( 706 ,  806 , and  906 , respectively) are comprised of at least two different materials having different heat deflection temperatures. For example, materials  702  and  704  may be different from one another, materials  802  and  804  may be different from one another, and, materials  902  and  904  may be different from one another. The closure materials may then deform at different rates at a given temperature, causing the closures to flex or stretch. 
         [0030]      FIG. 10  depicts an optional over-cap  1002  that may be used over any of the closures described herein. Over-cap  1002  may be necessary if the heat from the filled material causes substantial deformation of the sides  1004 . Over-cap  1002  may be metal, or a plastic with a heat-deflection temperature higher than that of the top  1006 . Over-cap  1002  may substantially surround sides  1004  and may cover a portion of an outer-most panel, while not covering the remainder of the top  1006 , to allow for expansion of top  1006 . Although  FIG. 10  shows over-cap  1002  to be of essentially the same height as side  1004 , over-cap  1002  may be shorter or longer than side  1004 . Over-cap  1002  may be press-fitted to attach to the closure. Alternatively, the sides  1004  of the closure may have external threads (not shown) and the over-cap  1002  may be coupled to the closure with threads on the inside of the over-cap (not shown). 
         [0031]    An advantage to embodiments of the present invention is that the closure may accept all of the volume change of a hot-filled container where a metal closure cannot. Embodiments of the closure may be molded from a plastic or other suitable flexible material, and may change shape to compensate for the change in internal pressure due to hot fill. Compensating for the pressure change primarily in the closure rather than the container body may free up a push-up base of the container to be designed more with structural integrity in mind, or assist the push-up base in accepting the volume change. This will also allow greater design freedom for label panels, and assist in opening the process window for the design of the push-up portion of the container base. 
         [0032]    Additionally, in an exemplary embodiment, the closure may be in contact with the product in the container and/or have the capability to sense the temperature of the product in the container. The closure may have the capability to change color or shape with heat. This would be useful, for example, if the container were for a bottled coffee, or soup, or a beverage for a child. The color or shape could indicate if the product is at a predetermined temperature, or too hot. 
         [0033]    In another exemplary embodiment, a figure or figurine may form or be attached to the closure. When the product in the container is heated, for example, in a microwave, the pressure buildup inside the container may cause a flexible portion of the figure to either depress or extend, for example, the figure&#39;s eyes or tongue may bulge, or other features of the figure may change shape, indicating a heated or over-heated product. 
         [0034]    In an exemplary embodiment, the amount of deformation of the closure may be related to the amount of vacuum on the container. This will allow for a quick visual inspection to determine whether the container is properly sealed. 
         [0035]    In an exemplary embodiment, the closure may have a diameter of greater than or equal to 48 millimeters (mm). In another exemplary embodiment, the closure may have a diameter of up to about 120 mm. In another exemplary embodiment, the closure may have a diameter of between about 63 mm to about 120 mm. In another exemplary embodiment, the closure may be used on containers of between about eight ounces to about five gallons. 
         [0036]    The embodiments illustrated and discussed in this specification are intended only to teach those skilled in the art the best way known to the inventors to make and use the invention. Nothing in this specification should be considered as limiting the scope of the present invention. All examples presented are representative and non-limiting. The above-described embodiments of the invention may be modified or varied, without departing from the invention, as appreciated by those skilled in the art in light of the above teachings. It is therefore to be understood that, within the scope of the claims and their equivalents, the invention may be practiced otherwise than as specifically described.