Tamper-evident cap and container neck

Abstract

A tamper-evident, snap-on, screw-off closure is used with a specially shaped container neck. The neck has at least one first helical thread on an upper neck stretch portion, and at least one external ratchet tooth on a locking wall portion below the upper neck stretch portion. The closure has an upper skirt having at least one second helical thread mating with the first helical thread of the neck. A downward extending lower skirt portion includes an outer skirt portion and a shoulder extending inwardly from said outer skirt portion. A frangible section interconnects the shoulder and the upper skirt portion. At least one substantially vertical castle projection is formed upstanding from the shoulder, preventing upward deformation of the lower skirt portion without breaking the frangible section. The lower skirt portion has at least one internal ratchet tooth, and is formed with a line of weakness extending through the outer skirt portion and the shoulder. The lower skirt has a tear tab which, when pulled, fractures the lower skirt on a vertical line. Continued pulling on the tab sequentially fractures the frangible section.

1 . A container closure for use with a container neck of the type having an upper opening, a downward extending upper neck stretch portion below said opening, said upper neck stretch portion having an exterior, at least one first helical engagement thread around said exterior of said upper neck stretch portion, a locking wall portion below said upper neck stretch portion, said locking wall portion comprising a lower neck stretch portion offset outwardly relative to said upper neck stretch portion and a first shoulder extending inwardly from said lower neck stretch portion to said upper neck stretch portion, at least one external tooth on said locking wall portion, 
 said closure having a top, a downward extending upper skirt portion depending from said top, at least one second helical engagement thread around said interior of said upper skirt portion shaped to mate with said at least one first helical engagement thread, a lower skirt portion below said upper skirt portion, said lower skirt portion comprising an outer skirt portion offset outwardly relative to said upper skirt portion and a second shoulder extending inwardly from said outer skirt portion to said upper skirt portion, a frangible line of weakness interconnecting said upper skirt portion and said second shoulder, at least one castle projection joined to and upstanding from said second shoulder to prevent upward deformation of said lower skirt portion without breaking said frangible line of weakness, at least one internal tooth on said lower skirt portion shaped to engage said at least one external tooth to prevent unscrewing of said closure relative to said neck without breaking said frangible line of weakness.    
     
     
         2 . The closure of  claim 1  in which said castle projection extends substantially vertically from said lower skirt portion.  
     
     
         3 . The closure of  claim 1  in which said castle projection is spaced from said upper skirt portion.  
     
     
         4 . The closure of  claim 1  in which lower skirt portion includes a plurality of said substantially vertical castle projections circumferentially spaced from said upper skirt portion.  
     
     
         5 . The closure of  claim 4  in which said lower skirt portion is formed with a substantially vertical line of weakness extending adjacent at least one of said substantially vertical castle projections adjacent said upper skirt portion, whereby said at least one substantially vertical castle projection is a tamper-evident feature of said closure.  
     
     
         6 . The closure of  claim 1  in which said at least one internal tooth is located on said outer skirt portion.  
     
     
         7 . A container closure for use with a container neck of the type having an upper opening, a downward extending upper neck stretch portion below said opening, said upper neck stretch portion having an exterior, at least one first helical engagement thread around said exterior of said upper neck stretch portion, a locking wall portion below said upper neck stretch portion, said locking wall portion comprising a lower neck stretch portion offset outwardly relative to said upper neck stretch portion and a first shoulder extending inwardly from said lower neck stretch portion said upper neck stretch portion, at least one external tooth on said locking wall portion, 
 said closure having a top, a downward extending upper skirt portion depending from said top, said upper skirt portion having an interior, at least one second helical engagement thread around said interior of said upper skirt portion shaped to mate with said at least one first helical engagement thread, a lower skirt portion below said upper skirt portion, said lower skirt portion comprising an outer skirt portion offset outwardly relative to said upper skirt portion and a second shoulder extending inwardly from said outer skirt portion to said upper skirt portion, a frangible line of weakness interconnecting said upper skirt portion and said second shoulder, at least one substantially vertical castle projection upstanding from said second shoulder to prevent upward deformation of said lower skirt portion without breaking said frangible line of weakness, at least one internal tooth on said lower skirt portion shaped to engage said at least one external tooth to prevent unscrewing of said closure relative to said neck without breaking said frangible line of weakness,    said at least one first helical engagement thread and said at least one second helical engagement thread being shaped such that when said closure is moved directly axially downward on said neck without relative rotation of said closure and said neck, said at least one first helical engagement thread and said at least one second helical engagement thread slip passes each other and then interengage,    said second shoulder and said outer skirt portion are formed with a line of weakness extending through said second shoulder and said outer skirt portion.    
     
     
         8 . The closure of  claim 7  in which said at least one substantially vertical castle projection is located adjacent said line of weakness.  
     
     
         9 . The closure of  claim 7  in which said line of weakness comprises a groove formed through said second shoulder and said outer skirt portion, said second shoulder formed having a first web material bridging said groove and said outer skirt portion formed having a second web material bridging said groove.  
     
     
         10 . The closure of  claim 9  in which said first and second web materials are separated by a gap adjacent the intersection of said second shoulder and said outer skirt portion.