Patent Publication Number: US-7708159-B2

Title: Plastic container

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to plastic containers, preferably those used for carbonated products, such as soda, beer and carbonated water. More particularly, the present invention relates to molded plastic containers, such as injection molded and/or blow molded plastic containers. 
   It has long been desirable to improve the stability of plastic containers, particularly round plastic containers, to enhance the conveyance, palletizing and shipment of empty containers from the injection molder or blow molder to the container filler. This has been particularly true in the water, beer and beverage industries. In addition, during the filling process, stable empty plastic containers improve depalletizing, conveying and filling speeds. Bottlers and manufacturers generally move empty containers by means of table top conveyors, and transfer the plastic containers in and out of labeling, palletizers and fillers with transfer arms. The transfer arms can facilitate the containers falling over, and often the containers do fall over. This reduces filling efficiency, causes production difficulties and increases scrap. In many cases this causes jams in the manufacturing lines and creates a domino effect, knocking over other containers that may have similar unstable characteristics. The center of gravity of the empty plastic containers impacts the propensity of the container to tip over during the manufacturing, shipping and filling processes, i.e., the higher the center of gravity the more unstable the container. 
   In addition to the foregoing, consumers who drink beverages clearly desire more stable plastic containers. For example, when a container is opened, undesirably the volume of liquid can spill if the container is tipped at a certain angle by an irregular movement or a certain amount of uncontrolled force to the upper portion of the container. Thus consumers would clearly desire a more stable plastic container wherein the container does not easily tip and spill the contents of the container. The lower the center of gravity of the plastic container the more stable the container, whether the container is empty, partially filled or fully filled. 
   Therefore, it is a principal object of the present invention to provide a more stable plastic container. 
   It is a still further object of the present invention to provide a plastic container with an improved and lowered center of gravity, which provides a reduced tendency for the container to tip or fall. 
   It is an additional object of the present invention to improve the tip angle, i.e., the angle at which the container starts to fall, on plastic containers and thereby increasing the tipping angle for empty, partially filled or filled containers. 
   Further objects and advantages of the present invention will appear hereinbelow. 
   SUMMARY OF THE INVENTION 
   In accordance with the present invention the foregoing objects and advantages are readily obtained. 
   The plastic container of the present invention comprises: 
   a hollow body of plastic material having a lower supporting base portion, a side wall portion extending upwardly from the base portion, a neck portion extending upwardly from the sidewall portion, and an opening at the top of the neck portion; 
   wherein the neck portion has an upper screw threaded outer surface for holding a screw threaded closure, a tamper bead beneath the screw threaded outer surface having a top and bottom portion thereof, and a support ring beneath the tamper bead having a top and bottom portion thereof; and 
   wherein the weight of the neck portion is from 2.5 to 4.4 grams and preferably from 3 to 4 grams. 
   Preferably, the distance from the top of the neck portion to the bottom of the tamper bead is from 0.310 inch to 0.525 inch and preferably from 0.400 inch to 0.420 inch, and the distance from the bottom of the tamper bead to the bottom of the support ring is from 0.250 inch to 0.125 inch and preferably from 0.175 inch to 0.200 inch. 
   The container is preferably a round container and may have a shoulder portion extending upwardly and inwardly from the sidewall portion to the neck portion. Advantageously, the container of the present invention has a lower center of gravity than a comparable container without the features of the present invention. Indeed, the ratio of center of gravity to height is lowered in the present containers by from 3 to 15 percent, and preferably over 5 percent and preferably from 8 to 10 percent. 
   In a preferred embodiment the tamper bead is discontinuous; however, one may also provide a continuous tamper bead. The container is for carbonated beverages, as soda, beer and carbonated water, as with a gas range of from 20 to 75 psi and essentially any suitable plastic material can be used. 
   The present invention also contemplates one or a plurality of protrusions in the tamper bead which preferably are equally spaced around the periphery thereof. These may desirably be located on the top or bottom of the tamper bead and serve to facilitate removal of the closure from the tamper evident band on the closure. 
   The present invention also provides an improved process for lowering the center of gravity of a plastic container for holding carbonated beverages, which comprises: 
   providing a hollow body of plastic material having a lower supporting base portion, a side wall portion extending upwardly from the base portion, a neck portion extending upwardly from the sidewall portion, and an opening at the top of the neck portion; 
   wherein the neck portion has an upper screw threaded outer surface for holding a screw threaded closure, a tamper bead beneath the screw threaded outer surface having a top and bottom portion thereof, and a support ring having a top and bottom portion thereof beneath the tamper bead; and 
   including the steps of lowering the distance from the top of the neck portion to the bottom of tamper bead, lowering the distance from the bottom of the tamper bead to the bottom of the support ring, and reducing the weight of the neck portion. 
   Further features of the present invention will appear hereinbelow. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be more readily understandable from a consideration of the accompanying drawings, wherein: 
       FIG. 1  is a perspective view of a conventional neck portion for a hollow plastic container; 
       FIG. 2  is a perspective view of the neck portion of a hollow plastic container of the present invention; 
       FIG. 3  is a side elevational view of a conventional plastic container, and 
       FIG. 4  is a side elevational view of an improved plastic container of the present invention based on the container configuration of  FIG. 3 ; 
       FIG. 5  is a side elevational view of a second embodiment of a conventional plastic container, and 
       FIG. 6  is a side elevational view of an improved plastic container of the present invention based on the container configuration of  FIG. 5 ; and 
       FIG. 7  is a side elevational view of a third embodiment of a conventional plastic container, and 
       FIG. 8  is a side elevational view of an improved plastic container of the present invention based on the container configuration of  FIG. 7 . 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   Referring to the drawings,  FIG. 1  shows a conventional neck portion  10  and  FIG. 3  shows a first conventional plastic container  50  including the neck portion of  FIG. 1 .  FIG. 2  shows the neck portion  30  of the present invention and  FIG. 4  shows an improved container  60  of the present invention with the plastic container configuration of  FIG. 3  and including the neck portion of  FIG. 2 . 
   The neck portion  10  of  FIG. 1  includes an opening  12  at the top of the neck portion, an upper screw threaded outer surface  14  for holding a threaded closure, a tamper bead  16  beneath the screw threaded outer surface and running continuously around the circumference of the neck portion, and a support ring  18  beneath the tamper bead, also running continuously around the circumference of the neck portion and extending outwardly beyond the outward extent of the threaded portion and the tamper bead. The tamper bead  16  has a top portion  20  and a bottom portion  22 , and the support ring  18  also has a top portion  24  and a bottom portion  26 . The top of the neck portion  28  is also shown. 
   The neck portion  30  of  FIG. 2  also includes an opening  32  at the top of the neck portion generally from 25 to 30 mm wide from the outer edge of the neck portion and preferably from 26 to 28 mm wide, an upper screw threaded outer surface  34  for holding a threaded closure, a tamper bead  36  beneath the screw threaded outer surface, and a support ring  38  beneath the tamper bead. However, in accordance with the preferred embodiment of the present invention, the tamper bead  36  runs discontinuously around the circumference of the neck portion while the support ring  38  runs continuously around the circumference of the neck portion and extends outwardly beyond the outward extent of the threaded portion and the tamper bead. The discontinuous tamper bead  36  has a top portion  40  and a bottom portion  42 , and the support ring  38  also has a top portion  44  and a bottom portion  46 . The top of the neck portion  48  is also shown. 
   Conventional hollow plastic container  50  of  FIG. 3  includes the neck portion  10  of  FIG. 1 . Container  50  includes a lower supporting base portion  52 , a sidewall portion  54  extending upwardly from the base portion and neck portion  10  extending upwardly from the sidewall portion. Container  50  also includes a shoulder portion  56  extending upwardly and inwardly from the sidewall portion to the neck portion, although many container configurations do not include a shoulder portion. 
   Hollow plastic container  60  of the present invention as shown in  FIG. 4  includes the neck portion  30  of  FIG. 2 . Similar to container  50 , the container  60  of the present invention includes a lower supporting base portion  62 , a side wall portion  64  extending upwardly from the base portion, and neck portion  30  extending upwardly from the sidewall portion. Container  60  also includes shoulder portion  66  extending upwardly and inwardly from the sidewall to the neck portion. 
   The container configuration shown in  FIG. 4  is representative only and a wide variety of shapes can be used with the neck portion of the present invention. Thus, many container configurations do not have a shoulder portion and a wide variety of base and sidewall configurations may be readily employed. 
   A key feature of the containers of the present invention is the lowering of the center of gravity. The lower the center of gravity the more stable the container and the less likely the container will tip during processing or handling. The center of gravity is the point at which if a body is suspended it would be perfectly balanced. For symmetrical bodies of uniform material the center of gravity is at the geometrical center. For non-symmetrical bodies the center of gravity needs to be determined. 
   The center of gravity of conventional container  50  of  FIG. 3  is shown at  58 ; whereas the center of gravity of container  60  of the present invention is shown at  68 . It can be seen that the center of gravity  68  is significantly lower than the center of gravity  58 . This will be discussed further hereinbelow. 
   Key features of the plastic container  60  and neck portion  30  of the present invention include the following. The weight range of the neck portion is from 2.5 to 4.4 grams and preferably 3 to 4 grams. The distance from the top of the neck portion  48  to the bottom of the tamper bead  42  is from 0.310 inch to 0.525 inch, preferably from 0.400 inch to 0.420 inch. The distance from the bottom of the tamper bead  42  to the bottom of the support ring  46  is from 0.250 inch to 0.125 inch, preferably from 0.175 inch to 0.200 inch. 
   The center of gravity (COG) to height ratio is significant. This ratio allows one to normalize the center of gravity for containers of different heights into a consistent range. Conventional containers have a COG/height ration of from 0.4 to 0.6. In accordance with the present invention one can readily lower the ratio from 3 to 15% and preferably from 8 to 10%. For example, if the height of the container is 8.00 inches and the COG for that container is at 4.00 inches, the starting ratio is 0.5. In accordance with the present invention one can reduce this ratio to 0.4999 to 0.425, which is quite significant. 
   Comparing the conventional container  50  of  FIG. 3  with the improved container  60  of the present invention of  FIG. 4 , the following improved results were obtained. 
   
     
       
         
             
           
             
                 
             
             
               FIG. 3 container 
             
             
                 
             
           
          
             
                 
             
          
         
         
             
             
             
          
             
                 
               Height 
               8.480 inch 
             
             
                 
               COG 
               4.470 inch 
             
             
                 
               COG/height ratio 
               0.527 
             
             
                 
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
                 
             
             
               FIG. 4 container 
             
             
                 
             
           
          
             
                 
             
          
         
         
             
             
             
          
             
                 
               Height 
               8.250 inch 
             
             
                 
               COG 
               4.100 inch 
             
             
                 
               COG/height ratio 
               0.497 
             
             
                 
               Improvement 
               5.7 percent 
             
             
                 
                 
             
          
         
       
     
   
   The tilt angle is also significant. This refers to the angle at which the container tilts over. A test to determine tilt angle may be performed by placing the container on a horizontal surface. The surface is slowly inclined and the angle of the surface at which the container starts to fall is the tilt angle. In accordance with the present invention the tilt angle is increased by from 0.5 to 3 degrees, which is significant and validates the improved stability of the containers of the present invention. 
     FIG. 5  is a second embodiment of a conventional plastic container  70 , and  FIG. 6  is an improved container  80  of the present invention based on the container configuration of  FIG. 5 . 
   Conventional hollow plastic container  70  of  FIG. 5  includes neck portion  10  of  FIG. 1 , a lower supporting base portion  72 , a sidewall portion  74  extending upwardly from the base portion, and neck portion  10  extending upwardly from the sidewall portion. Container  70  also includes a shoulder portion  76  extending upwardly and inwardly from the sidewall portion. The COG is shown at  78 . 
   Hollow plastic container  80  of the present invention shown in  FIG. 6  includes the neck portion  30  of  FIG. 2 . Similar to container  70 , the container  80  of the present invention includes a lower supporting base portion  82 , a sidewall portion  84  extending upwardly from the base portion, shoulder portion  86  extending upwardly and inwardly from the sidewall portion, and neck portion  30  extending upwardly from the shoulder portion. 
   The center of gravity of conventional container  70  of  FIG. 5  is shown at  78 ; whereas, the center of gravity of container  80  of the present invention is shown at  88 . It can be clearly seen that the COG  88  is significantly lower than the COG  78 . Moreover, a comparison of the conventional container  70  of  FIG. 5  with the improved container  80  of the present invention of  FIG. 6  gave the following improved results. 
   
     
       
         
             
           
             
                 
             
             
               FIG. 5 container 
             
             
                 
             
           
          
             
                 
             
          
         
         
             
             
             
          
             
                 
               Height 
               8.750 inch 
             
             
                 
               COG 
               4.280 inch 
             
             
                 
               COG/height ratio 
               0.489 
             
             
                 
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
                 
             
             
               FIG. 6 container 
             
             
                 
             
           
          
             
                 
             
          
         
         
             
             
             
          
             
                 
               Height 
               8.520 inch 
             
             
                 
               COG 
               3.840 inch 
             
             
                 
               COG/height ratio 
               0.451 
             
             
                 
               Improvement 
               7.9 percent 
             
             
                 
                 
             
          
         
       
     
   
     FIG. 7  is a third embodiment of a conventional plastic container  90 , and  FIG. 8  is an improved container of the present invention  100  based on the container configuration of  FIG. 7 . 
   Conventional hollow plastic container  90  of  FIG. 7  includes neck portion  10  of  FIG. 1 , a lower supporting base portion  92 , a sidewall portion  94  extending upwardly from the base portion, and neck portion  10  extending upwardly from the sidewall portion. Container  90  also includes a shoulder portion  96  extending upwardly and inwardly from the sidewall portion. The COG is shown at  98 . 
   Hollow plastic container  100  of the present invention shown in  FIG. 8  includes the neck portion  30  of  FIG. 2 . Similar to container  90 , the container  100  of the present invention includes a lower supporting base portion  102 , a sidewall portion  104  extending upwardly from the base portion; shoulder portion  106  extending upwardly and inwardly from the sidewall portion, and neck portion  30  extending upwardly from the shoulder portion. 
   The center of gravity of conventional container  90  of  FIG. 7  is shown at  98 ; whereas the center of gravity of container  100  of the present invention is shown at  108 . It can be clearly seen that the COG  108  is significantly lower than the COG  98 . Moreover, a comparison of the conventional container  90  of  FIG. 7  with the improved container  100  of the present invention of  FIG. 8  gave the following improved results. 
   
     
       
         
             
           
             
                 
             
             
               FIG. 7 container 
             
             
                 
             
           
          
             
                 
             
          
         
         
             
             
             
          
             
                 
               Height 
               8.800 inch 
             
             
                 
               COG 
                4.35 inch 
             
             
                 
               COG/height ratio 
               0.494 
             
             
                 
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
                 
             
             
               FIG. 8 container 
             
             
                 
             
           
          
             
                 
             
          
         
         
             
             
             
          
             
                 
               Height 
               8.57 inch 
             
             
                 
               COG 
               4.04 inch 
             
             
                 
               COG/height ratio 
               0.471 
             
             
                 
               Improvement 
               4.8 percent 
             
             
                 
                 
             
          
         
       
     
   
   It is to be understood that the invention is not limited to the illustrations described and shown herein, which are deemed to be merely illustrative of the best modes of carrying out the invention, and which are susceptible of modification of form, size, arrangement of parts and details of operation. The invention rather is intended to encompass all such modifications which are within its spirit and scope as defined by the claims.