Abstract:
A base including an inwardly and upwardly projecting flexible surface within a continuous seating ring supports a generally cylindrical wall extending upward from the base. A plurality of annular inwardly projecting, and vertically flexible rings interrupting the cylindrical wall. At least one of rings projects inwardly more than some others of the rings to achieve an improved sidewall crush resistance A shoulder portion, includes a plurality of vertical ribs separating a plurality of vacuum responsive panels. The vertical flexibility of the bottle sidewall reduces the amount of flexing required in the shoulder panels and base to accommodate the same vacuum development, and enhances the total amount of post capping vacuum development that can be accommodated by the bottle as a whole.

Description:
BACKGROUND 
   Blow-molded plastic bottles can be useful in containing hot-filled beverages and foods. The present disclosure relates particularly to a hot-filled plastic bottle that has increased flexibility through thinner wall thickness, yet retains a sidewall resistance to ovalization and other distortion that is at least as great as comparable bottles. 
   Garver et al., U.S. Pat. No. 5,067,622, discloses a bottle made of PET that is expressly configured for hot filled applications. The bottle&#39;s body sidewall is rigidized against radial and longitudinal vacuum distortion so that paper labels can be applied to the bottle. The rigidized sidewall is achieved by providing a plurality of radially inward, concave ring segments which are spaced apart from one another and separated from one another by cylindrically shaped flats or land segments. In addition, the amorphous threaded mouth of the bottle is rigidized by gussets molded into the bottle at the junction of the neck and shoulder portion of the bottle to resist deformation when the bottle is capped. To accommodate the post capping vacuum, a bulbous vacuum deformation area is provided in the shoulder adjacent the bottle neck, a plurality of vacuum deformation panels are provided in a frusto-conical portion of the shoulder, and a further vacuum deformation panel is provided in the base. As a result, any post capping vacuum is confined to the specifically designated areas of the bottle and the sidewall remains undistorted. The lack of post capping sidewall distortion is disclosed to be the result of a critical sizing of the ring segments relative to the land segments in combination, to some extent, with the crystallinity level, which is disclosed to be greater than 30%. Other bottles made of PET that have sidewall including spaced ring segments designed to rigidize the sidewall are disclosed, for example, in U.S. Pat. Nos. 6,923,334; 6,929,139 and 7,051,890. 
   Despite the various features and benefits of the structures of the forgoing and other similar disclosures, there remains a need for hot-fillable bottle made of plastic that has a price advantage achieved through a thinner wall thickness, yet retains a resistance to sidewall ovalization and other unwanted deformation that is at least as great as comparable bottles. 
   SUMMARY 
   These several needs are satisfied by a blow-molded bottle having a base including a generally continuous seating ring surrounding an inwardly and upwardly projecting flexible surface. A generally cylindrical wall extends upward from the base defining a longitudinal axis of the bottle. A plurality of annular inwardly projecting, and vertically flexible rings extend about the cylindrical wall perimeter interrupting the cylindrical wall. At least one of the plurality of rings projects inwardly more than some others of the plurality of rings. A shoulder portion extends upward from the cylindrical wall to a neck leading to a cappable opening. The shoulder includes a plurality of vertical ribs separating a plurality of vacuum responsive panels. The ends of the vertical ribs are smoothly continuous with the shoulder surface. 
   In one aspect, the seating ring of the base is sufficiently stable as to maintain a substantially constant diameter during changes in internal pressure of the bottle due to post capping shrinkage of the contents due to cooling. The stabilization of the base seating ring can be achieved by including a step immediately radially inside the lowest point of the seating ring. Flexibility is imparted to the inwardly and upwardly projecting surface within the seating ring and step by providing a convex portion between the step inside the seating ring and a central ring surrounding the longitudinal axis of the bottle. The central ring can define the outer perimeter of a shaped surface that can deflect and disburse incoming fluid during the filling operation. 
   In another aspect, the shoulder includes a circular ring defining a lower margin of the shoulder and a circular neck below the finish defining an upper margin of the shoulder. The ribs are in the form of upright columns arranged in spaced relation to each other between the upper and lower margins of the shoulder. The width of each of the ribs can be tapered from a wider lower end to a narrower upper end. An outer surface of the ribs is inwardly inclined from the lower end to the upper end and can have a substantially linear lower portion and a slightly bowed upper portion. The width of each of the plurality of flexible panels separating the upright columns can also be tapered from a wider lower portion to a narrower upper portion. The corners of the flexible panels at the junction of the ribs and margins can be arcuate to inhibit the initiation of creases or folds that can contribute to unwanted surface distortion. 
   In another aspect, the sidewall can be a series of generally cylindrical surfaces at a substantially constant radius from the longitudinal axis of the bottle. Each of the cylindrical surfaces is separated from adjacent cylindrical surfaces by an annular inwardly projecting and vertically flexible ring, there being a plurality of such rings over the vertical extent of the entire sidewall. At least one of the rings, situated between at least two others of the rings, projects inwardly more than the vertically adjacent rings, above and below, to provide resistance against radial collapse or ovalization of the cylindrical wall as a whole. More than one of the rings having the greater inward projection can be included in a single bottle sidewall, but uniform inward projection of the rings is to be avoided. The thickness of the cylindrical surfaces of the sidewall and the annular inwardly projecting rings is such that the sidewall as a whole can lengthen and shorten in response to pressure changes with the bottle. 
   One feature of the present invention is the use of increased controlled flexibility through proper shaping of the sidewall to achieve a resistance to sidewall ovalization or other radial deformation that is at least as great as comparable bottles, yet produced with a bottle having a price advantage achieved through a thinner wall thickness that accommodates the post capping vacuum that develops as a result of hot fill packaging of foods and beverages. The vertical flexibility of the bottle sidewall reduces the amount of flexing required in the shoulder panels and base to accommodate the same vacuum development. Alternatively, the enhanced vertical flexibility of the bottle sidewall enhances the total amount of vacuum development that can be accommodated by the bottle as a whole. 
   Other features of the present invention and the corresponding advantages of those features will be come apparent from the following discussion of the preferred embodiments of the present invention, exemplifying the best mode of practicing the present invention, which is illustrated in the accompanying drawings. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like referenced numerals designate corresponding parts throughout the different views. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevation view of a bottle embodying the present invention. 
       FIG. 2  is a side elevation view of a second bottle embodying the present invention. 
       FIG. 3  is a side elevation view of a third bottle embodying the present invention. 
       FIG. 4  is a bottom plan view of the bottles shown in  FIGS. 1 through 3 . 
       FIG. 5  is a partial vertical outline view of the outer surface of the base of the bottles in  FIGS. 1 through 3  taken along line A-A of  FIG. 4 . 
       FIG. 6  is a partial vertical outline view of the outer surface of the shoulder of the bottles in  FIGS. 1 through 3  taken along line A-A of  FIG. 4 . 
       FIG. 7  is an outline view of the outer surface of the shoulder taken at line B-B of  FIGS. 1 through 3 . 
       FIG. 8  is an overlapping outline view of the outer surface of a bottle of the present invention before and after being hot filled and capped, the view being taken along line A-A of  FIG. 4 . 
       FIG. 9  is a side by side outline view of the outer surface of a bottle of the present invention before and after being hot filled and capped, the view being taken through the middle of the posts in the shoulder. 
       FIG. 10  is a side by side outline view of the outer surface of a bottle of the present invention before and after being hot filled and capped, the view being taken through the middle of the vacuum responsive panels in the shoulder. 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
   A bottle  10  of a first embodiment is shown in  FIG. 1  in an un-distorted condition to have a base  12  including a generally continuous seating ring  14  capable of supporting the bottle  10  and any contents on an underlying surface, not shown. The base  12  includes a heel  16  outside the seating ring  14  that curves upward to a generally cylindrical portion  18 . The cylindrical portion  18  can be considered as the upper margin of the base  12  and the lower margin of a generally cylindrical sidewall  20  that extends upward from the base  12  to an upper sidewall margin  22 . The sidewall  20  is shown to be generally axially symmetric about a longitudinal axis Y of the bottle  10 . The sidewall  20  includes a label panel portion  24  that extends between an upper label margin protrusion  26  and a lower label margin protrusion  28 . The label panel portion  24  includes a plurality of cylindrical wall segments  30  having a constant diameter D. The cylindrical wall segments  30  are separated from each other by a plurality of annular inwardly projecting, and vertically flexible rings  32  that extend completely around the cylindrical wall perimeter to interrupt the vertical extent of the label panel portion  24 . One of the rings  34  is seen to project inwardly more than the other rings  32 . Additional annular inwardly projecting, and vertically flexible rings  36  are situated within the sidewall  20  above and below the label panel portion  24  to provide added vertical flexibility for the bottle while enhancing the resistance of the sidewall  20  to ovalization and other unwanted distortion. The additional rings  36  are shown to have an inwardly projecting dimension similar to that of ring  34 . The inwardly projecting dimension of the rings  34  and  36  can be more than two times the inwardly projecting dimension of the rings  32 . 
   A shoulder portion  38  extends upward from the upper sidewall margin  22  to a neck  40  leading to a cappable opening  42 . The cappable opening  42  is shown to be surrounded by a finish  44  including a thread element  46  above a pilfer ring engaging feature  48  and a support ring  50 . Finishes having other geometries and features can be used on the present containers in place of the illustrated finish  44 . The shoulder portion  38  includes a smooth circumferentially continuous lower surface  52  immediately adjacent the upper sidewall margin  22 . The continuous lower surface  52  is shown to be separated from the upper sidewall margin  22  by an optional cylindrically continuous step  54 . The shoulder portion  38  also includes a plurality of vertical ribs  56  separating a plurality of vacuum responsive panels  58 . The lower ends  60  of the vertical ribs  56  are smoothly continuous with the continuous lower surface  52  while the upper ends  62  of the vertical ribs  56  smoothly transition into the neck  40 . The term “smoothly” is employed here to indicate the absence of any step or other demarcation between the ends  60  and  62  of the vertical ribs  56  and the vertically adjoining surfaces  52  and  40 , respectively. The width of each of the ribs  56  is seen to be tapered from a wider lower end  60  to a narrower upper end  62 . The vacuum responsive panels  58  include generally planar or slightly outwardly bowed surface  64  bounded by the vertical ribs  56  and the vertically adjoining surfaces  52  and  40 . The corners  66  of the panels  58  are generally arcuate in the plane of the surface  64  to inhibit the initiation of creases or folds that can contribute to unwanted surface distortion. 
   A bottle  10  of a second embodiment is shown in  FIG. 2  in an un-distorted condition to have a base  12  including a generally continuous seating ring  14  capable of supporting the bottle  10  and any contents on an underlying surface, not shown. The base  12  includes a heel  16  outside the seating ring  14  that curves upward to a generally cylindrical portion  18 . The cylindrical portion  18  can be considered as the upper margin of the base  12  and the lower margin of a generally cylindrical sidewall  20  that extends upward from the base  12  to an upper sidewall margin  22 . The sidewall  20  is shown to be generally axially symmetric about a longitudinal axis Y of the bottle  10 . The sidewall  20  includes a label panel portion  24  that extends between an upper label margin protrusion  26  and a lower label margin protrusion  28 . The label panel portion  24  includes a plurality of cylindrical wall segments  30  having a constant diameter D. The cylindrical wall segments  30  are separated from each other by a plurality of annular inwardly projecting, and vertically flexible rings  32  that extend completely around the cylindrical wall perimeter to interrupt the vertical extent of the label panel portion  24 . Unlike the first embodiment, one of the rings  32  is situated immediately adjacent to the upper label margin protrusion  26  and another of the rings  32  is situated immediately adjacent to the lower label margin protrusion  28 . Like the first embodiment, one of the rings  34  is seen to project inwardly more than the other rings  32 . Additional annular inwardly projecting, and vertically flexible rings  68  are situated within the sidewall  20  above and below the label panel portion  24  to provide added vertical flexibility for the bottle while enhancing the sidewall crush resistance of the bottle. The additional rings  68  are shown to have an inwardly projecting dimension somewhat smaller than rings  32 . The inwardly projecting dimension of the rings  34  can be more than three times the inwardly projecting dimension of the additional rings  68 . 
   As in the first embodiment, a shoulder portion  38  of the second embodiment extends upward from the upper sidewall margin  22  to a neck  40  leading to a cappable opening  42 . The cappable opening  42  is shown to be surrounded by a finish  44  including a thread element  46  above a pilfer ring engaging feature  48  and a support ring  50 . The shoulder portion  38  includes a smooth circumferentially continuous lower surface  52  immediately adjacent the upper sidewall margin  22 . The continuous lower surface  52  is shown to be separated from the upper sidewall margin  22  by an optional cylindrically continuous step  54 . The shoulder portion  38  also includes a plurality of vertical ribs  56  separating a plurality of inset vacuum responsive panels  58 . The lower ends  60  of the vertical ribs  56  are smoothly continuous with the continuous lower surface  52  while the upper ends  62  of the vertical ribs  56  smoothly transition into the neck  40 . The vacuum responsive panels  58  include generally planar or slightly outwardly bowed surface  64  bounded by the vertical ribs  56  and the vertically adjoining surfaces  52  and  40 . The corners  66  of the panels  58  are generally arcuate in the plane of the surface  64  to inhibit the initiation of creases or folds that can contribute to unwanted surface distortion. 
   A bottle  10  of a third embodiment is shown in  FIG. 3  in an un-distorted condition to have a base  12  including a generally continuous seating ring  14  capable of supporting the bottle  10  and any contents on an underlying surface, not shown. The base  12  includes a heel  16  outside the seating ring  14  that curves upward to a generally cylindrical portion  18 . The cylindrical portion  18  can be considered as the upper margin of the base  12  and the lower margin of a generally cylindrical sidewall  20  that extends upward from the base  12  to an upper sidewall margin  22 . The sidewall  20  is shown to be generally axially symmetric about a longitudinal axis Y of the bottle  10 . The sidewall  20  includes a label panel portion  24  that extends between an upper label margin protrusion  26  and a lower label margin protrusion  28 . The label panel portion  24  includes a plurality of cylindrical wall segments  30  having a constant diameter D. The cylindrical wall segments  30  are separated from each other by a plurality of annular inwardly projecting, and vertically flexible rings  32  that extend completely around the cylindrical wall perimeter to interrupt the vertical extent of the label panel portion  24 . Unlike the first embodiment, but similar to the second embodiment, one of the rings  32  is situated immediately adjacent to the upper label margin protrusion  26  and another of the rings  32  is situated immediately adjacent to the lower label margin protrusion  28 . Like the first embodiment, one of the rings  34  is seen to project inwardly more than the other rings  32 . An additional annular inwardly projecting, and vertically flexible ring  68  is situated within the sidewall  20  below the label panel portion  24  to provide added vertical flexibility for the bottle while enhancing the sidewall crush resistance of the bottle. The additional ring  68  is shown to have an inwardly projecting dimension somewhat smaller than rings  32 . The inwardly projecting dimension of the rings  34  can be more than three times the inwardly projecting dimension of the additional ring  68 . 
   A shoulder portion  38  of the third embodiment extends upward from an additional inwardly projecting ring  69  positioned above the upper sidewall margin  22  to a neck  40  leading to a cappable opening  42 . The cappable opening  42  is shown to be surrounded by a finish  44  including a thread element  46  above a pilfer ring engaging feature  48  and a support ring  50 . The shoulder portion  38  includes a smooth circumferentially continuous lower surface  52  immediately adjacent the inwardly projecting ring  69  above upper sidewall margin  22 . The continuous lower surface  52  is shown to be separated from the upper sidewall margin  22  by the inwardly projecting ring  69 . The shoulder portion  38  also includes a plurality of vertical ribs  56  separating a plurality of vacuum responsive panels  58 . The lower ends  60  of the vertical ribs  56  are smoothly continuous with the continuous lower surface  52  while the upper ends  62  of the vertical ribs  56  smoothly transition into the neck  40 . The vacuum responsive panels  58  include generally planar or slightly outwardly bowed surface  64  bounded by the vertical ribs  56  and the vertically adjoining surfaces  52  and  40 . Unlike the first and second embodiments, the surfaces  64  of the vacuum responsive panels  58  smoothly blend into the neck  40  without any noticeable step or boundry. 
   A base  12  that can be used on the various embodiments of bottle  10  is shown in  FIGS. 4 and 5  in an un-distorted condition to include a heel  16  outside the seating ring  14  that curves upward to the generally cylindrical portion  18  shown in  FIGS. 1 ,  2  and  3 . The seating ring  14  surrounds an inwardly and upwardly projecting flexible surface  70 . A step  72  can provided immediately radially inside the seating ring  14  that provides some radial stabilization for the seating ring  14 . A convex portion  74  can extend inward from the step  72  to a central ring  76  surrounding the longitudinal axis Y of the bottle. The central ring  76  is shown to define the outer perimeter of a shaped surface  78  that is generally perpendicular to the axis Y. The shaped surface  78  can include a radial series of ribs  80  and depressions  82  that can assist in deflecting and disbursing incoming fluid during a filling operation of a bottle  10  incorporating the base  12 . 
     FIGS. 6 and 7  show outline views of the outer surface of a shoulder portion  38  of a container  10  in an un-distorted condition.  FIG. 6  shows the generally planar or slightly outwardly bowed surface  64  of the vacuum responsive panels  58  to be inset from the vertically adjoining surface  52  by a distance d 1  that is greater than the inset d 2  from the vertically adjoining surface  40  that defines the neck. In preferred embodiments of the container  10 , the distance d 1  is at least twice the distance d 2 . In the third embodiment of the container  10  shown in  FIG. 3 , the inset d 2  from the vertically adjoining surface  40  diminishes to essentially zero. It will also be seen that the lower ends  60  of the vertical ribs  56  are smoothly continuous with the continuous lower surface  52  while the upper ends  62  of the vertical ribs  56  smoothly transition into the neck  40 . Further the portion  84  of the vertical ribs  56  near the lower ends  60  are generally planar while the portion  86  of the vertical ribs  56  near the upper ends  62  can be outwardly bowed. In horizontal cross-section, it will be seen that the outer surfaces  64  of the vacuum responsive panels  58  are outwardly bowed. In the plane defined by the line B-B shown in  FIG. 7  the inset distance d 3  of the surface  64  is between the distances d 1  and d 2 . In the plane defined by the line B-B the width w of each of the ribs  56  is less than at the lower end  60  and greater than at the upper end  62 . 
     FIG. 8  shows an overlapping outline of the outer surface of a bottle  10  before and after being hot filled and capped. The outline can be considered a view being taken along line A-A of  FIG. 3  so that the left side of the figure passes through the center of a shoulder panel  58  and the right side of the figure passes through the center of a shoulder rib  56 . The overlapping outlines are formed with the finish  44  exactly in line with all portions of the bottle  10  below the support ring  50  being free to move in response to the vacuum developed within the bottle as a result of the hot filling, capping and cooling. One observable change is a conventional and expected inward displacement of the surface  64  of the vacuum responsive panel  58  so that the surface  64  moves from a substantially planar or slightly convex configuration, as seen in  FIG. 6 , to a concave configuration. Another more dramatic change is an unconventional vertical movement of the base  12  in relation to the finish  44  so that the overall height of the container  10  is substantially shorter. This shortening of the overall height of the container  10  occurs substantially entirely within the sidewall  20  as a result of the vertical flexing of the rings  32 ,  34 ,  36  and/or  68 . Some movement of the surface  70  within the base  12  also occurs, but may be difficult to see in  FIG. 8 . 
     FIGS. 9 and 10  show a side by side outline view of the outer surface of a bottle  10  before and after being hot filled, capped, and cooled. In  FIG. 9 , the view is taken through the middle of the shoulder ribs  56 , while in  FIG. 10  the view is taken through the middle of the shoulder vacuum response panels  58 . In both  FIGS. 9 and 10 , the bottle  10  is assumed to be supported on a common surface S, and the remainder of the bottle  10  is allowed to move in response to the vacuum developed within the bottle  10  as a result of being hot filled, capped, and cooled. In these comparative views, the movement of the outer surface  70  with the base  12  is easier to be seen. The movement of the base surface  70  is not dramatic, although the volume displacement as a result of this movement is not insignificant. The movement of the vacuum responsive panel surfaces  64  is very apparent, but may be deceiving. The displaced volume as a result of the movement of the panel surfaces  64  is only moderate when compared with the change in volume that occurs as a result of the overall vertical shortening of the bottle  10  through the vertical flexing of the rings  32 ,  34 ,  36  and/or  68 . The change in volume that occurs as a result of the overall vertical shortening of the bottle  10  has been found to be greater than the sum of the volumes displaced as a result of the movement of surfaces  64  and  70 . This surprising result is achieved by thinning the sidewall  20  of the bottle  10  to increase the flexibility of the rings  32 ,  34 ,  36  and/or  68 . The thinning is achieved by decreasing the amount of polymer used to form the bottle, which consequently also diminishes the cost of the bottle. Hence, a superior performing bottle is achieved at lower cost, yet the presence of the series of rings  32  and  34 , and to a lesser extent  36  and/or  68 , enable the bottle to withstand side impact and ovalization at least as well as comparable prior art bottles having more robust construction. 
   While these features have been disclosed in connection with the illustrated preferred embodiments, other embodiments of the invention will be apparent to those skilled in the art that come within the spirit of the invention as defined in the following claims.