Overcap Having Improved Fit

Abstract

The combination of an injection-molded, snap-on cap and a blow-molded, plastic container are designed to act together to provide a seal that prevents a loss of freshness to the porous product stored within, regardless of variations in the manufacturing process. Instead of a rounded ridge on the container, the ridge has a flattened section on its lower half. On the inside of the snap-on cap, the ridge has two flat surfaces. A first flat surface is designed to fit snugly against the flat surface on the ridge of the container, even at the extreme range of small container/large cap. Interferences between the container and cap at points other than the intended flat surfaces can cause the closure to become point-to-point, rather than the desired surface-to-surface, so other portions of the inside of the cap are designed to not touch the container, preventing interferences. The design has been shown to dramatically reduce the absorption of moisture by an enclosed product, demonstrating that a desirable seal is formed.

1 . A container and overcap, comprising: 
 a hollow plastic container having an opening comprising a rim, wherein an upper portion of said rim is rounded and a lower portion of said rim is essentially flat in cross-section;    a flexible, plastic, snap-on overcap that removable fits over said rim of said container, said cap comprising a base portion sized to cover said opening of said container and a flange extending essentially perpendicularly to said base portion, wherein an inner surface of said flange contains a circumferential ridge having a peak, wherein a face of said ridge is essentially flat in cross-section so that said face of said ridge seals against said lower portion of said rim of said container, wherein said flange contacts said container only at said lower portion of said rim;    whereby said cap provides a seal to said hollow plastic container.    
   
   
       2 . The container and overcap of  claim 1 , wherein both of said container and said cap are molded.  
   
   
       3 . The container and overcap of  claim 1 , wherein said container is blow molded.  
   
   
       4 . The container and overcap of  claim 1 , wherein said cap is injection molded.  
   
   
       5 . The container and overcap of  claim 1 , wherein said lower portion of said lid and said face of said ridge provide a surface-to-surface contact.  
   
   
       6 . The container and overcap of  claim 1 , wherein a nominal inner diameter of said overcap at said peak is equal to a nominal outer diameter of said rim of said container plus the manufacturing tolerance of said container minus twice an overlap needed for tightness minus the manufacturing tolerance of said cap.  
   
   
       7 . The container and overcap of  claim 1 , wherein a nominal inner diameter of said cap at locations away from said ridge is greater than a nominal outside diameter of a rim of said container at a largest diameter minus a manufacturing tolerance of said container plus a manufacturing tolerance of said overcap.  
   
   
       8 . The container and overcap of  claim 1 , wherein said container is formed of a high-density polyethylene.  
   
   
       9 . The container and overcap of  claim 1 , wherein said cap is formed of a low-density polyethylene.  
   
   
       10 . The container and overcap of  claim 1 , further comprising a freshness seal affixed to said opening of said container with an adhesive.  
   
   
       11 .- 23 . (canceled)