Abstract:
A blow-molded plastic container is provided suitable for hot-filling under pressurize-fill conditions, and under gravity-fill conditions. The container includes opposing handgrips within panels, which lack hinges and thus do not function as conventional vacuum panels as the inward deformation is spread beyond the panels. The hand grip includes a distal, relatively stiffened portion formed by a sidewall that forms a thumb piece and a proximal, relatively un-stiffened portion the smooth merges into a cylindrical sidewall of the container.

Description:
BACKGROUND  
         [0001]    This application relates to blow-molded containers, and more particularly to hot-fillable containers having integral grip portions formed therein.  
           [0002]    Perishable beverage and food products are often placed into containers at elevated temperatures. In a conventional hot-fill process, the liquid or flowable product is charged into a container at elevated temperatures, such as 180 to 190 degrees F., under approximately atmospheric pressure. Because a cap hermetically seals the products within the container while the products are at the hot-filling temperature, hot-fill plastic containers are subject to negative internal pressure (that is, relative to ambient pressure) upon cooling and contraction of the products and any entrapped air in the head-space.  
           [0003]    It has been an inherent goal of conventional hot-fill container design to form stiff cylindrical portions (in transverse cross section) that maintain a cylindrical shape upon cooling. Thus, conventional hot-fill containers include designated flexing portions—vacuum panels—that deform when subject to typical hot-fill negative internal pressures. The inward deflection of the vacuum panels tends to equalize the pressure differential between the interior and exterior of the container so as to enhance the ability of the cylindrical sections to maintain an attractive shape, to enhance the ease of labeling, or like commercial appeal. Some container designs are symmetric about a longitudinal centerline and designed with stiffeners to maintain the intended cylindrical shape while the vacuum panels deflect. For example, U.S. Pat. Nos. 5,178,289, 5,092,475, and 5,054,632 teach stiffening portions or ribs to increase hoop stiffness and eliminate bulges while integral vacuum panels collapse inwardly. U.S. Pat. No. 4,863,046 is designed to provide volumetric shrinkage of less than one percent in hot-fill applications.  
           [0004]    Other containers include a pair of vacuum panels, each of which has an indentation or grip portion enabling the container to be gripped between a user&#39;s thumb and fingers. For example, U.S. Pat. No. 5,141,120 teaches a bottle having a hinge continuously surrounding a vacuum panel, which includes indentations for gripping. In response to cooling of the container contents, the hinge enables the entire vacuum panel to collapse inwardly. U.S. Pat. No. 5,141,121 similarly teaches a bottle having an outward bulge that inverts in response to cooling of the container contents. Each of the patents referred to herein by patent number is incorporated by reference in its entirety.  
           [0005]    Some hot-fill technology employs charging the product under atmospheric pressure (that is, gravity filling). However, metering the products under a positive pressure pumping system has been found to increase the accuracy and precision of the product volume charged into the container. Such positive pressure filling systems enable better accuracy and precision of the predetermined product volume, better control of the headspace volume, and other benefits. The metering typically subjects the container to a positive pressure (relative to ambient pressure) of a few PSI during charging. Typical charging pressures may be 1 to 2 PSI, although 5 PSI or greater may be encountered in certain circumstances. After filling, the pressure is typically released by exposing the contents to approximately atmospheric pressure prior to capping. It is a goal to provide improved containers.  
         SUMMARY  
         [0006]    Conventional containers often include stiffeners to enhance the stiffness of portions thereof. Some containers even have stiffeners within the vacuum panels themselves. It has been found that stiffened containers may have a tendency to form a crease or kink in the container sidewall upon being subjected to the positive pressures inherent in pressure filling technology and techniques. In this regard, the sidewall forms an undesirable outer bulge or crease, thereby weakening the sidewall. Further, sometimes the sidewall crease does not snap back towards a cylindrical shape upon pressure release. Thus, stiffeners intended to maintain a cylindrical container shape or resist distortion, in some circumstances, may result in a container that is overly stiff and subject to creasing, and the stiffeners tend to inhibit the creased sidewall from snapping back upon pressure release. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0007]    [0007]FIG. 1 is a perspective view of a container according to an aspect of the present invention;  
         [0008]    [0008]FIG. 2 is a rear elevation view of the container of FIG. 1;  
         [0009]    [0009]FIG. 3 is a front elevation view of the container of FIG. 1;  
         [0010]    [0010]FIG. 4 is a side elevation view of the container of FIG. 1;  
         [0011]    [0011]FIG. 5 is a transverse cross sectional view taken through line  5 - 5  in FIG. 4;  
         [0012]    [0012]FIG. 6A is a color deformation diagram of a first side of a bottle indicating the magnitude of inward and outward deformation of the bottle between its pre-filling, blow molded state and its final, hot-filled, cooled state with a scale in millimeters;  
         [0013]    [0013]FIG. 6B is a color deformation diagram of the first side of the bottle of FIG. 6A but employing a different color scale;  
         [0014]    [0014]FIG. 7A is a color deformation diagram of a first side of another bottle;  
         [0015]    [0015]FIG. 7B is a color deformation diagram of the first side of the bottle of FIG. 7B but employing a different color scale;  
         [0016]    [0016]FIG. 8A is a color deformation diagram of a second side of the bottle of FIG. 6;  
         [0017]    [0017]FIG. 8B is a color deformation diagram of the second side of the bottle of FIG. 8A but employing a different color scale;  
         [0018]    [0018]FIG. 9A is a color deformation diagram of the second side of the bottle of FIG. 7A; and  
         [0019]    [0019]FIG. 9B is a color deformation diagram of the second side of the bottle of FIG. 9A but employing a different color scale. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0020]    As illustrated in FIGS. 1 through 5, a container  10  includes a neck  12 , a dome portion  14 , a body  16  and a base or bottom  18 . Neck  12  extends upwardly from dome  14  and includes threads formed thereon for receiving a closure (not shown). Dome  14  extends between neck  12  and body  16 . Base  18  encloses the lower portion of body  16 , and may include any upwardly extending portion or geometry (not shown). Body  16  includes a pair of opposing panels  20  disposed between a rear sidewall portion  24  and a front sidewall portion  26 . Rear sidewall  24  is opposite front sidewall  26 , and each are substantially cylindrical in shape (that is, each is a segment of a substantially cylindrical shape). Preferably, the cylindrical shape preferably is circular in transverse cross section. Each of portions  24  and  26  includes horizontal ribs for stiffening so as to maintain the substantially cylindrical shape. Thus, each of sidewalls  24  and  26  is suitable for receiving a conventional label thereon. For ease of reference, each of FIGS. 1 through 5 includes mutually orthogonal axes x, y, and z. The positive x-axis is defined as oriented from rear sidewall  24  to front sidewall  26 . Vertical axis z is co-linear with the longitudinal centerline of container  10 .  
         [0021]    As best shown in FIGS. 4 and 5, each panel  20  includes a peripheral edge  22  including: a substantially straight distal edge  28   a ; an opposing, substantially straight proximal edge  28   b ; an upper shoulder  30   a ; and a lower shoulder  30   b . Edges  28   a  and  28   b  preferably smoothly merge into rear and front portions  24  and  26 . Shoulders  30   a  and  30   b  extend between panel  20  and a cylindrical portion of container  10  above and below panel  20 . Preferably panel  20  is substantially planar, as best shown in FIGS. 1 and 5. Edges  28   a  and  28   b  provide, in transverse cross section, the transition between the circular sides  24  and  26  and the subtending straight portion  20 , and between the circular sides of body  16  above and below panel  20  and the subtending straight portion  20 . In this regard, panel  20  has an outer edge having an overall rectangular shape formed by substantially parallel sides  28   a  and  28   b  and by substantially parallel shoulders  30   a  and  30   b . As best shown in FIG. 4, each of shoulders  30   a  and  30   b  form an arc where it meets the flat portion of panel  20 . A portion of shoulder  30   a  is shown in phantom in FIG. 5 to further illustrate such configuration.  
         [0022]    As shown schematically in FIG. 5, panel  20  preferably is formed by an removable insert  62  into a mold  60  in which container  10  is blown. Such an insert preferably is capable of being shimmed relative to the remainder of the mold such that the depth of panel  20  can be modified to modify the volume, thereby enabling the volume of the containers to be adjusted in a predetermined manner. Shims are indicated schematically by reference numeral  64 , and are shown schematically in outline in FIG. 4 generally to indicate that panel  20  may be shimmed. Persons familiar with blow molding technology and design will understand forming containers in molds that employ removable inserts, and will understand that the present invention is not limited to the particular shape or configuration of shims, nor to the particular outline of the shimmed portion, that is shown.  
         [0023]    Further, aspects of the present invention (including but not limited to panel configuration and design, shimming aspects, and others) are illustrated by employing a particular geometry of container  10 , including, but not limited to, panels  20 . The present invention is not limited to such particular geometry, but rather encompasses any structure that is recited in the claims or structure that functions as described in the claims.  
         [0024]    Grip  22  extends inwardly from panel  20  so as to form an indentation suitable for gripping by a user&#39;s hand. As best shown in FIGS. 1, 4, and  5 , grip  22  includes a main grip surface  34  and a grip wall  36  (FIG. 2). As shown in phantom in FIGS. 3 and 4, grip surface  34 , which preferably is planar, is inclined relative to plane x-z (that is, the plane defined by axes x and z) by an angle A 1  such that grip  22  has a depth (that is, the radial distance between the projected, imaginary cylinder and a point on grip surface  34 ) that is non-uniform within grip  22 . Angle A 1  is measured between the z-axis and the projection of the innermost surface (that is, the portion that protrudes toward centerline z) of panel  20  onto the y-z plane (indicated by line z′) as shown in FIGS. 2 and 3. The magnitude of angle A 1  may be determined according to the desired grip characteristics (including depth and other dimensions), panel dimensions (including depth and other dimensions), and related parameters, as well as for its deformation characteristics as described below. For the particular configuration of the embodiment shown in the Figures. for a 48 ounce volumetric size, angle A 1  preferably is between 4 and 12 degrees, more preferably between 5 and 10 degrees, and even more preferably approximately 7 degrees.  
         [0025]    Thus, grip wall  36  is formed by a grip upper wall  38   a , distal grip wall  38   b , and lower grip wall  38   c , which vary in depth. Each grip wall  38   a ,  38   b , and  38   c  has an outer transition  40   a ,  40   b , and  40   c , respectively, that preferably gradually merges wall  38   a ,  38   b , and  38   c  into panel  20  and has an inner transition  42   a ,  42   b , and  42   c  that preferably abruptly (that is, having a small radius so as to substantially form a comer) merges wall  38   a ,  38   b , and  38   c  into grip surface  34 .  
         [0026]    In this regard, grip wall  36  forms a modified C-shape such that each wall  38   a ,  38   b , and  38   c  has a straight section that merges into a rounded transition between upper wall  38   a  and distal wall  38   b , and between lower wall  38   c  and distal wall  38   b . According to an aspect of the present invention (which is independent of other aspects described herein) and as shown in the Figures., upper and lower walls  38   a  and  38   c  have a depth that increases at distal ends that merge with distal wall  38   b , and a depth that gradually decreases to substantially zero at opposing proximal ends such that walls  38   a  and  38   c  smoothly merge into panel  20 . Distal wall  38   b  has a depth that, upwardly toward upper wall  38   a , gradually increases to form a thumb piece (or, opposite, a finger piece) indentation  44  substantially at the portion of panel  20  having the greatest depth. In this regard, panel  20  may substantially be a plane that is inclined to the substantially vertical panel proximal edge  28   b . Further, upper wall  38   a  is inclined from a horizontal reference to receive a user&#39;s thumb (or forefinger or index finger) at a natural gripping angle, thereby enhancing gripping ease and comfort.  
         [0027]    According to an aspect of the present invention, grip surface  34  (that is, the flat portion of grip  22 ) has a boundary that is formed by proximal edge  28   b  of panel  20  and is not indented therefrom (that is, a portion of grip surface  34  at the open end of its C-shape is unbounded by walls  38   a ,  38   b , and  38   c ). Rather, grip surface  34  smoothly merges into rear sidewall  34  without a hinge or like structure therebetween. Grip surface  34  gradually increases in depth from rear sidewall portion  24  toward front sidewall portion  26  and gradually increases in depth from a lower portion thereof (defined by lower wall  38   c ) toward an upper portion thereof (defined by upper wall  38   a ), thereby forming thumb piece  44 . Further, grip walls  38   a ,  38   b , and  38   c  are oriented substantially radially so as to provide a relatively large moment of inertia to resist deformation inherent in hot-filling technology. Such a configuration provides a comfortable grip while thumb piece  44  enables secure grasping.  
         [0028]    According to another aspect of the present invention, container  10  lacks hinges that enhance or facilitate deformation of a portion thereof. Further, even though panel edges  28   a ,  28   b ,  30   a , and  30   b  visually resemble conventional vacuum panels, panel  20  does not collapse inwardly in response to negative internal pressure corresponding to cooling subsequent to a hot-fill process. Rather, inward deflection of the container walls relative to its pre-filled state is distributed beyond panel  20 . Therefore, the maximum magnitude of such deflection of the container  10  is less than the maximum magnitude of corresponding deflection of prior art containers (that is, to achieve the same volumetric decrease). As shown in FIG. 6, the maximum magnitude inward deflection of the embodiment of container  10  for a 48 ounce container size is less than approximately 1.8 millimeters.  
         [0029]    Further, according to another aspect of the present invention, panel  20  includes a handgrip  22  having a stiffened wall  36  proximate the distal portion of grip  22  (that is, relative to the user&#39;s hand position) that resists deformation upon internal vacuum conditions, as well as a substantially un-stiffened proximal portion or edge (into which grip  22  merges). Thus, the relatively stiffened portion and relatively unstiffened portion are disposed on opposing sides of grip  22 . In this regard, the stiffening provided by grip wall  36  increases as the depth of grip wall  36  increases. Thus, the grip wall  36  is most stiff at the upper left portion of grip  34  (as oriented in FIG. 4), and the stiffening gradually decreases toward the proximal edge of upper wall  38   a  and lower wall  38   c . The stiffening where grip  34  merges into rear sidewall  24  is minimal.  
         [0030]    As indicated in FIG. 5, an angle A 2  is formed by the planar portion of grip  22  and the x-z plane, which is indicated on FIG. 5 by line x′. The magnitude of angle A 2  may be chosen according to the desired depth of grip  22  and like dimensions. In the embodiment shown in the Figures., angle A 2  may be preferably between approximately 5 and 20 degrees, more preferably between 8 and 16 degrees, and most preferably approximately 12 degrees. Grip  22  forms and angle A 3  with a tangent line T 1  drawn on rear sidewall  24  and edge  28   b . The magnitude of angle A 3  depends upon the desired depth of grip  22 , as well as upon and angle A 2  and the arc A 4  defining the rear portion  24 , which is indicated by arc A 4  on FIG. 5. Preferably, angle A 3  is approximately between 35 and 65 degrees, preferably between 45 and 65 degrees, and more preferably about 50 degrees. The angles A 4  and A 5  defining rear and front sidewalls  24  and  26  are approximately 83 and 100 degrees, respectively.  
         [0031]    To illustrate the vacuum deformation characteristics of container  10 , and containers having like geometry, FIGS. 6A and 6B through  9 A and  9 B were produced by laser scanning a blow-molded container, and subsequently filling the container at a temperature of approximately 185 degrees at 1 to 2 PSI, releasing the pressure to expose the contents to atmospheric pressure, and capping the container while hot. After cooling, the filled container was again scanned to produce the data—that is, the graphic representation of the deformation of the bottle&#39;s surface from its pre-filled at-rest state, to it post-filling, cooled, vacuum deformed state—represented in the Figures. Such laser scanning technology is available from Digibotics, Inc. of Novi, Mich. FIGS. 6A and 6B show identical views of vacuum deformation of container  10 , but employing different color scales to correspond to the magnitude of the container deformation. Similarly, each of the figures designated by an A and B extension show the same view but employ different color scales. FIGS. 8A and 8B show the opposing side view of the same container as shown in FIGS. 6A and 6B. FIGS. 7A and 7B show views of another container, and FIGS. 9A and 9B show the opposing side view of the same container as shown in FIGS. 7A and 7B.  
         [0032]    As shown in FIG. 6A and 6B through  9 A and  9 B, container  10  as configured above produces container deformation (that is, deformation of a hot-filled container upon cooling) that is not limited to panel  20 , but rather is distributed over an area of the bottle that is larger than the panel area The deformation distribution is, at least in part, enhanced by the hingeless nature of panel  20  and/or handgrip  22 . Further, the Figures illustrated that the the stiffened portion deflects significantly less than the un-stiffened portion. The configuration, however, is not prone to sidewall collapse of early containers.  
         [0033]    Aspects of the present invention have been illustrated by employing the particular embodiment shown in the Figures. However, the present invention is not limited to the particular embodiment shown or described, but rather encompasses other container configurations embodying the inventive aspects described herein. Further, each aspect of the invention referred to in the specification is independent of other of such aspects such that the claims define the invention and no single aspect is relied upon as essential.