Patent Publication Number: US-8991628-B2

Title: Hot-fill jar base

Description:
This application is a Continuation in Part of U.S. Design patent application Ser. No. 29/379,000, filed Nov. 12, 2010. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is directed to the field of containers. In particular the field of the invention is directed to a minimum geometry container base. 
     2. Description of the Related Technology 
     Traditional plastic jar bases have been made similarly to the bases used in juice and isotonic drinks. These bases which perform well for hot-fill beverages at 185° F. are not good for enabling product evacuation in jar shaped containers. Jar shaped containers focus on improved product evacuation and typically use a conical base design. Such designs have a smaller process window, produce heavier containers and have issues with base sticking. 
       FIGS. 1(   a )- 1 ( c ) show standard volcano type bases  3 ( a )- 3 ( c ) used with a jar-type container  4 . A jar-type container  4  differs from a typical hot fill container by being filled at higher temperatures, typically 205° F. max. Jar-type containers also have larger finishes, currently up to 82 mm. Because of the larger finishes, a blow/trim process is primarily used to produce the larger finishes, therefore the finishes are thinner than injected finishes, and more susceptible to variation. 
     Therefore there is a need in the field to employ a jar base that is able to withstand the hot-filling process and provide good product evacuation. Additionally, creating a container that is lighter and has a larger process window is also desirable. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is an improved container base. 
     Another object of the present invention is a jar base able to withstand the hot-filling process. 
     Still yet another object of the present invention is base that enables construction of a lighter container. 
     Another object of the present invention is a jar base that provides a larger process window. 
     An aspect of the present invention may be a base for a hot-fill container comprising: a peripheral lip located radially from a longitudinal axis of the base; an inner lip located radially from the longitudinal axis of the base, wherein the inner lip is located closer to the longitudinal axis than the peripheral lip; and an inverted rib extending from the inner lip towards the longitudinal axis, wherein a bottom rib portion of the inverted rib smoothly curves towards the longitudinal axis. 
     Another aspect of the present invention may be a hot-fill container comprising: a body; a finish; a base comprising; a standing surface; a concave planar surface extending towards a longitudinal axis; and an inverted rib located within the concave planar surface, wherein the inverted rib has a bottom rib portion that smoothly curves towards the longitudinal axis. 
     These and various other advantages and features of novelty that characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described a preferred embodiment of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1(   a )- 1 ( c ) shows containers with volcano type bases. 
         FIG. 2  is a bottom up perspective view of a container base made in accordance with an embodiment of the present invention. 
         FIG. 3  is a bottom up plan view of the container base shown in  FIG. 2 . 
         FIG. 4  is a top down view of the container base shown in  FIG. 2 . 
         FIG. 5  is a side view of the container shown in  FIG. 2 . 
         FIG. 6  is a cross-sectional view of the container shown in  FIG. 3  taken along the line  6 - 6 . 
         FIG. 7  is a cross-sectional view of the container shown in  FIG. 3  taken along the line  7 - 7 . 
         FIG. 8  is a view of the container base shown used with an exemplary jar-type container. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     Hot-filling containers involves using plastic containers. Plastic containers are used due to their durability and lightweight nature. Polyethylene terephthalate (PET) is used to construct many of today&#39;s containers. PET containers are lightweight, inexpensive, recyclable and manufacturable in large quantities. 
     PET containers are used for products that traditionally were placed in glass bottles or jars. Often these products, such as juices and isotonics, were placed into the containers while the liquid product is at an elevated temperature, typically between 68° C.-96° C. (155° F.-205° F.) and usually about 85° C. (185° F.). When packaged in this manner, the hot temperature of the liquid is used to sterilize the container at the time of filling. This process is known as hot-filling. The containers that are designed to withstand the process are known as hot-fill containers. 
     A container that is used in the hot-fill process is subject to additional stresses on the container that can result in the container failing during storage or handling or to be deformed in some manner. The sidewalls of the container can become deformed and/or collapse as the container is being filled with hot fluids. The rigidity of the container can decrease after the hot-fill liquid is introduced into the container. The top-load of a container may also be affected. 
     After being hot-filled, the hot-filled containers are capped and allowed to reside at about the filling temperature for a predetermined amount of time. The containers and stored liquid may then be cooled so that the containers may be transferred to labeling, packaging and shipping operations. As the liquid stored in the container cools, thermal contraction occurs resulting in a reduction of volume. This results in the volume of liquid stored in the container being reduced. The reduction of liquid within the sealed container results in the creation of a negative pressure or vacuum within the container. If not controlled or otherwise accommodated for, these negative pressures result in deformation of the container which leads to either an aesthetically unacceptable container or one which is unstable. The container must be able to withstand such changes in pressure without failure. 
     Hot-fillable jar-type containers should be able to provide good product evacuation as well as being capable of withstanding the rigors of the hot-filling process. Now referring to the  FIGS. 2-7 , an exemplary base made in accordance with an embodiment of the present invention is shown. 
       FIG. 2  shows a bottom up perspective view of a container base  10  made in accordance with an embodiment of the present invention. The base  10  shown in  FIG. 2  has six inverted ribs  25  located symetrically and radially about the longitudinal axis A. The longitudinal axis A passes through the center  20  of the base  10  as well as the container for which the base  10  is part. The position of the inverted ribs  25  forms an asterisk shape. While there are six inverted ribs  25  shown in the figures it should be understood that more or less ribs may be used in the formation of the base provided that sufficient structure was still present in order to maintain stability after the hot-fill process and further enable sufficient product evacuation. 
     The base  10  has an outer surface  12  which is located radially from the longitudinal axis A. At a distal end of the outer surface  12  is the standing surface  9  which merges with the a peripheral lip  11 . The standing surface  9  is that part of the container&#39;s surface that the container will rest on when the container is standing. The peripheral lip  11  is the part of the base  10  which merges with the concave underside. The top portion  14  of the base  10  is a transition area between the base  10  and the container to which it is attached. Located below the top portion  14  is a base inset region  13 . The base inset region  13  is typically used to maintain panel geometry through the hotfill process. 
     The bottom surface of the base  10  has an inner lip  16 . The inner lip  16  is located closer to the longitudinal axis A than the peripheral lip  11  Inner lip  16  is located both radially and vertically closer to the center  20  of the base  10  than the peripheral lip  11 . From the inner lip  16  a concave smooth surface  31  extends towards the central lip  24  which surrounds the center  20 . However, the concave smooth surface  31  does not contact the central lip  24 . The concave smooth surface  31  has formed therein the inverted ribs  25 . When the base  10  is placed on a surface, the inverted ribs  25  are recessed with respect to the concave smooth surface  31 . 
     The inverted ribs  25  have a smoothly inwardly curving rib perimeter  15 , which forms the junction between the concave smooth surface  31  and the rib side  18 . It should be understood that when the term “inwardly” is used it means the direction towards the center  20  and the central lip  24 , this direction may encompass both a vertical and horizontal component. The rib side  18  extends inwardly to the bottom rib portion  22  of the inverted rib  25 . The rib side  18  has a curve that enables the smooth downward curve of the inverted rib  25 . The surface of the rib side  18  is triangular shaped. 
     Between each of the inverted ribs  25  are the rib connectors  23 . The rib connectors  23  extend from the rib perimeter to the central lip  24 . In the embodiment shown, the rib connectors  23  are inwardly curved. The bottom rib portion  22  curves downwardly from the apex  29 , which is that part of the rib perimeter  15  that is located proximate to the inner lip  16 . In the embodiment shown the apex  29  contacts the inner lip  16 . The bottom rib portion  22  curves downwardly to the central lip  24 . 
     In the base  10  shown in the figures, the bottom rib portion  22  has a radius of curvature R 1 , which is dependent on the base diameter. R 1  may be within the range 1.000 inches to 5.000 inches. In the embodiment shown in the figures the curvature of the bottom rib portion  22  is smooth. By “smooth” it is meant that there are no abrupt changes in the curvature. The concave planar surface  31  has a radius of curvature of R 2 . Additionally, the radius of curvature R 2 , is dependent upon the base diameter and may be between the ranges of 2.000 inches to being a straight line. Furthermore, the radius of curvature R 3  of the rib connector  23  may be between the ranges of 0.020 inches to 1.000 inches. The radius of curvature R 1  is typically smaller than the radius of curvature R 2  and greater than the radius of curvature R 3 . 
     The inverted ribs  25  are spaced equidistantly around the inner lip  16 . Because the inner lip  16  is circular, the apexes  29  of the inverted ribs  25  are located every 60° along the circumference of the circle formed by the inner lip  16 . The rib connectors  23  are each located equidistantly from two adjacent apexes  29  and are located equidistantly from each other. In  FIGS. 2-7  the rib connectors  23  are located 60° from each other. Each of the rib connectors  23  are located 30° away from each of the adjacent apexes  29  when taken along the circumference of the circle formed by the inner lip  16 . The rib connectors  23  contact the central lip  24 . Additionally, the bottom rib portion  22  contacts the central lip  24 . 
     An angle α is formed between the rib perimeters  15  with the vertex located at the rib connector  23 . The angle α is less than 90°. The distance between the two rib sides  18  at the point closest to the rib perimeter  15  of the inverted rib  25  is D 2 . The ranges of D 2  may be between 0.100 inches to 0.200 inches. It should be understood that the dimensions are dependent upon the diameter of the base  10 . The base  10  would also be useable with high R 1  values as well as wider or narrower D 2  values. The distance D 2  between the two sides  18  enables the inverted rib  25  to provide additional structure and support to the base  10 . The distance D 1  is the distance between the two sides of a rib perimeter  15 . The distance D 1  decreases as the rib perimeter  15  approaches the apex  29  of the inverted rib  25 . 
     Now referring to  FIG. 6 , wherein a cross-sectional view of the container shown in  FIG. 3  is taken along the line  6 - 6 . Distance D 3  shows the distance taken from the bottom of the central lip  24  to the bottom of the base  10  that is co-planar with the standing surface  9 . Distance D 4  is the distance taken from the midpoint of base inset region  13  to the bottom of the base  10  that is co-planar with the standing surface  9 . The distance D 3  is equal to the distance D 4 . 
       FIG. 7  is a cross-sectional view of the container shown in  FIG. 3  taken along the line  7 - 7 . Distance D 5  shows the distance taken from the rib connector  23  to the bottom of the base  10  that is co-planar with the standing surface  9 . Distance D 6  is the distance taken from where the bottom rib portion  22  contacts the central lip  24  to the bottom of the base  10  that is co-planar with the standing surface  9 . The distance D 6  is greater than the distance D 5 . 
       FIG. 8  shows an exemplary container  5  that may be employed with the base  10 . In  FIG. 8 , container  5  is a jar-type container, having a jar-type body  2  and finish  3 . As noted elsewhere, a jar-type container differs from a typical hot fill container by being filled at higher temperatures (typically 205° F. max). Additionally, jar-type containers may have larger finishes (currently up to 82 mm). Because of the larger finishes, a blow/trim process is primarily used to produce the larger finishes, therefore the finishes are thinner than injected finishes, and more susceptible to variation. 
     The base  10  comprises a minimal geometry base design, which can withstand the typical hot fill temperatures ranges seen by jars while maintaining or improving weight, performance and product evacuation. The base  10  provides improved processing by providing larger process windows in general than the conical base and on par with those used in traditional bases employed in hot-filling. 
     In the process used with base  10  as shown, the base mold was swapped out while using the same body and preform. Once this was done, the process engineer had a wider range of control with oven heats while still producing a fit for use container. One of the primary improvements was reduced base sticking and the ability to “slide” the material over the base geometry to the heel portion of the jar like container, which in turn helped to reduce base “sag” from excess material. This produced stronger heels that helped to prevent denting. These improvements may be attributed to the reduced geometry. The base  10  is able to be lighter due to its shape, while maintaining functionality. 
     Furthermore, product evacuation is improved with the base  10  having inverted ribs  25  arranged in an asterisk shape than the evacuation achieved with the conical bases. By product evacuation it is meant that tests were conducted where filled jars were weighed and then the product was emptied using methods that a consumer may typically use (both tapping and spooning). With the base  10  there was a 19-32% increase in evacuated product based on weight. 
     Additionally, the base  10  having inverted ribs  25  arranged in an asterisk shape resists crowning and sagging better than the traditional or conical style bases. 
     It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.