Abstract:
The present invention relates to a plastic container with a substantially circular base, a lower body portion, a mid body portion, and an upper body portion, each having a respective width. The lower body portion is connected to the base and the mid body portion, the mid body portion lies between the lower and upper body portion, and the upper body portion is between the mid body portion and container neck. The mid body portion contains a substantially flat portion, with the flat portion merging into the upper and lower body portions. The container also has a waist located at approximately the center of the mid body portion, the waist having a width.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to a hollow blow-molded container, and more particularly to a uniformly shaped blow-molded container able to accommodate a hot-fill and sealing process without distortion. 
   2. Description of Related Art 
   Plastic containers adapted for hot filling and sealing are known in the art. However, producing a container that is able to withstand vacuum forces created by the process of hot-filling, capping, and cooling the container, while maintaining its structural integrity, still presents a challenge. 
   Many plastic containers utilize flexible panels to accommodate internal vacuum forces. U.S. Pat. Nos. 5,141,120 and 5,141,121 to Brown et al. disclose a hot fill container having opposing pinch grip indentations in the sidewall. These indentations collapse inwardly towards each other to accommodate internal forces that result from filling the container with high temperature liquid. U.S. Pat. No. 5,392,937 and Des. 344,457 to Prevot et al. disclose a grip structure that moves with the vacuum flex panel in response to the internal vacuum. Agrawal et al., U.S. Pat. No. 4,497,855 discloses a container with a plurality of recessed collapsed panels, separated by land areas, that allow uniform inward deformation under vacuum force. 
   However, the use of flex panels has its own limitations. Due to the increased amount of force transferred to the side walls, the amount of flex in each panel is limited. Thus, there is a need in the art for a container that is suitable for hot-fill processes that does not rely on the use of flex panels. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention is directed to a plastic container having upper, lower, and mid body portions, the base and body portions each having a respective width. In one preferred embodiment, the base is substantially circular. The lower body portion is connected to the base, the mid body portion is connected to the lower body portion, and the upper body portion is connected to the mid body portion at the end opposite to the lower body portion. A neck is connected to the upper body portion. 
   A substantially flat concave portion exists within the mid body portion, and this flat portion merges into the upper and lower body portions. There is also a waist at approximately the center of the mid body portion, the waist having a width. The width of the lower body portion can be equal to the width of the upper body portion. Further, the width of the lower body portion and the width of the upper body portion can be greater than the width of the base, and the width of the waist can be less than the width of the base. The mid body portion can have four substantially flat portions. In one embodiment of the invention, the flat concave portion is oval shaped. The waist can be substantially square in cross section, and can be situated evenly between the neck and the base. In a preferred embodiment of the invention, the flat portion of the container flexes inwardly and uniformly upon hot-filling and sealing of the neck with a closure. 
   The present invention is further directed to a container sidewall having the inventive features as described above. 
   The present invention is also directed to a method of minimizing asymmetrical distortion of a container upon hot filling and sealing of the container by manufacturing the container has described above. 
   This invention provides a container that is suitable for hot-fill application without the problems that exist in conventional solutions. The container provides for uniform distribution of internal vacuum forces, and does not require the presence of a flex panel, thus overcoming the challenges of the prior art. 
   Further objectives and advantages, as well as the structure and function of the preferred embodiments, will become apparent from a consideration of the description, drawings, and examples. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     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. 
       FIG. 1  depicts a front view of the container according to one embodiment of the present invention; 
       FIG. 2  depicts a cutaway view of the container of  FIG. 1  along line  2 - 2  looking up according to the present invention  FIG. 3A  depicts; 
       FIG. 3  depicts a cutaway view of the container of  FIG. 1  along line  3 - 3 , looking up according to the present invention; 
       FIG. 4  depicts a cutaway view of the container of  FIG. 1  along line  4 - 4 , looking up according to the present invention; and 
       FIG. 5  depicts a side view of the container according to one embodiment of the present invention, rotated 45° from  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   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. 
   The embodiment of container  100  as illustrated in  FIG. 1  has a base  102 , with body  104 , and neck  106  with finish  108 . The container body  104  can be described as having three portions: a lower body portion  110 , a substantially flat mid body portion  112 , and an upper body portion  114 . The lower body portion  110  is situated between the base  102  and a mid body portion  112 , the mid body portion is located between the lower body portion  110  and upper body portion 114 , and the upper body portion  114  sits between the mid body portion  112  and the neck  106 . 
   As depicted in  FIG. 1 , the base  102  is substantially circular and has rounded edges. In progressing from the base  102  to the lower body portion  110 , the rounded edges bow outwardly away from the center of the container, such that the circumference of the container body increases when moving upwards, away from the container base  102 . The container then reaches a maximum circumference, which is approximated by line  2 - 2  in  FIG. 1 . The cross section of the container at this maximum point is substantially circular, as shown in  FIG. 2 . The portion of the container which begins at the rounded base edges defines the lower body portion  110 . In the illustrated embodiment of  FIG. 1 , the lower body portion  110  is rounded. 
   Moving upwards along the container body from line  2 - 2 , the circumference of the container body begins to decrease as the container sidewall starts to bow inwardly. The circumference of the container continues to decrease, and the rounded shape of the lower body portion  110  transitions to a substantially flat sidewall flanked by corners, or corner edges  120 , on either side (see also  FIGS. 3 and 5 ). This portion where the sidewall is substantially flat is the central surface  118  of the present invention. The corners form the corner edges  120 , that run along the central surface  118 . 
   As illustrated in  FIG. 3 , the cross section of the container at the mid body portion  112  is substantially square. The corner edges  120  can vary from the illustrated sharp transition to a slightly more rounded configuration. This tightening of the rounded container body to a substantially square-shaped container body occurs within the mid-body portion  112 . The container sidewall along the mid-body portion  112  is substantially flat, but bows slightly inward towards the center of the container  100 . Thus, the container sidewall at the mid-body portion  112  is slightly concave in the vertical direction. This substantially flat but slightly concave portion of the sidewall, the central surface  118 , is visible in  FIGS. 1 ,  3 , and  5 . On either side of the central surface  118  is a corner edge  120 . 
   At the center of the mid-body portion is a container waist  116 , where the container body  104  is substantially square-shaped. The waist  116  is located approximately at line  3 - 3 , and has the cross section shown in  FIG. 3 . As illustrated in  FIG. 3 , the sides of the square (formed by the central surface  118 ) bow outwardly and are slightly rounded, and the portion of the sidewall adjacent to the central surface  118  tightens to form the corner edge  120 . In the illustrated embodiment, corner edges  120  are only present in the mid-body portion. 
     FIG. 5  is a side or edge view of container  100 , which illustrates the corner edge  120  of the present invention. The corner edge  120  is present in the mid body portion  112  adjacent to the central surface  118 . The corner edge  120  develops as the rounded lower body  110  transitions to the mid-body portion  112 , the mid body portion  114  having a substantially square cross section. The corner edge  120  is present along the mid body portion  112 , then begins to loosen and disappear as the mid body portion  112  transitions to the upper body portion  114 . More specifically, the corner edges  120  begin to disappear as the container body  104  once again expands in circumference and takes on a circular shape, as shown in,  FIG. 5 . In this illustrated embodiment, there are four corner edges  120  separating four central surfaces  118 . However, containers having 3, 5, 6 or more sides are within the scope of the invention. 
   Continuing upwards along the container  100 , the body  104  begins to again bow outwardly. This rounding of the container body  104  and increase in circumference occurs where the mid-body portion  112  merges with the upper body portion  114 . Like the lower body portion  110 , the upper body portion  114  of  FIG. 1  is rounded at and around the mid-section. The circumference of the container upper body  114  reaches a maximum point at approximately line  4 - 4  of  FIG. 1 . The circular cross section of the container  100  at this maximum point is illustrated at  FIG. 4 . From line  4 - 4  moving upwards, the container circumference decreases until the upper body portion  114  merges with the neck  106 . The neck  106  can include a finish  108  for attaching a closure, which can be, for example, threads. Other closure attachment structures known in the art can also be used. 
   The present invention is also directed to a method of blow molding the container  100  described above. The method of blow molding can be injection, stretch, or extrusion blow molding. In an exemplary embodiment, the container is prepared by extrusion blow molding. 
   The container can be blow molded from a thermoplastic material. The container can be made of a polyolefin such as polyethylene, for example low density polyethylene (LDPE) or high density polyethylene (HDPE), or polypropylene; a polyester, for example polyethylene terephthalate (PET), polyethylene naphtalate (PEN); or others, which can also include additives to vary the physical or chemical properties of the material. 
   In the illustrated embodiment, there are four central surfaces  118  separated by four corner edges  120 . The central surfaces  118  are substantially flat and are present primarily on the mid body portion. Accordingly, the corner edges  120  exist only in the mid body portion  112 . However, embodiments where the central surfaces  120  extend further into the lower  110  and upper body portions  114  are also possible. The central surfaces are also depicted as oval shaped in the Figures, but other circular or polygonal shapes are possible. 
   As depicted in the Figures, the diameter, or width, of the lower body  110  and upper body portions  114  are approximately equal. The widths of the upper  114  and lower body portions  110  are also greater than the width or diameter of the waist  116  of the mid body portion  112 . However, varying, asymmetrical dimensions, are also within the scope of this invention. Also, as discussed above, the base can circular, but it can also can be a variety of other suitable shapes, such as square-like, elliptical, triangular, rectangular, and others. 
   The central surface  118  of the present invention eliminates or minimizes distortion in response to internal vacuum pressure that results from hot filling and capping the container  100  by the migration of the substantially flat geometry of the central surface  118  into the upper  114  and lower rounded body portions  112 . The present container  100  can be filled at a temperature of approximately 85° C. (185° F.), and can withstand temperatures of up to 87.78° C. (190° F.). Upon sealing, the central surface  118  flexes inwardly and evenly, distributing the vacuum forces such that the upper  114  and lower body portions  110  become a more flattened shape where the upper  114  and lower body portions  110  meet the mid body portion  112 . Again, the distribution of vacuum force, and thus the migration of the flat geometry into the upper  114  and lower body portions  110  occurs uniformly, such that the overall shape of the container  100  is maintained. As a result, container deformations such as buckling, collapse, or other undesirable side effects due to uneven distribution of vacuum forces are virtually eliminated. The end result is a highly attractive container, manufactured without the requirement of a flex panel. 
   The elimination of the conventional flex panel from the container has several advantages. One major benefit is easier manufacture, since the container  100  has less complicated components. This is particularly desirable in embodiments of the invention where the container  100  is small. In certain preferred embodiments, the present container  100  can be approximately four to six inches in height. Designing a flex panel for a container of this size can be a challenge, and the elimination of the flex panel facilitates manufacture. Without the requirement of a flex panel, it is easier to manufacture bottles of a smaller size. A small size is often desirable when manufacturing products for consumption, as it reduces content waste. This is particularly advantageous when the consumer is a child or any individual who does not want to consume a larger quantity of food/beverage. The small size also makes the product more portable, fitting easily into a purse, backpack, lunch box, or even a pocket. Further, certain products, such as vitamin supplements or nutritional drinks are only meant to be consumed in small quantities. The present invention is appropriate for all these uses. Of course, the present container is well-suited to be used in the manufacture of bottles of various sizes, including standard and larger size drink bottles. 
   Another benefit of the present invention is that the lack of panels makes for an aesthetically pleasing container. This is particularly apparent if the container is placed in a shrink sleeve. The lack of panels allows the shrink sleeve to neatly silhouette the shape of the container, without leaving any gaps between the container body and the sleeve. 
   The presently claimed container is suitable for holding, for example, fruit drinks, dairy-based drinks, shakes, energy/sports drinks, health drinks/nutritional supplements, and so on. The container is also suitable for gels, viscous liquids, and pourable solids. 
   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.