Thread formation for closure structures

Abstract

A closure structure which includes a container neck having an external thread to be engaged by an internal thread of a closure body for drawing the closure body tightly down onto the container neck. The external thread of the container neck includes a pad on a bottom thread turn. A sealing element of the closure body is drawn downwardly onto a sealing surface of the container neck to effect a seal. The pad is sized to have a depth which causes the internal thread of the closure body to be drawn downwardly during the final portion of the screwing-on of the closure body to the container neck. The presence of the pad reduces axial clearance between the external thread of the container neck and the internal thread of the closure body to prevent axial displacement of the closure body from the container neck to prevent leakage due to the sealing element of the closure body being axially displaced from the sealing surface of the container neck.

What is claimed is:  
     
         1 . A threading arrangement for engaging a first closure component to a second closure component, comprising: 
 a first closure component having a first sealing surface;    a second closure component having a second sealing surface;    a first thread formation on an outside of the first closure component and comprising a plurality of thread turns;    a second thread formation on an inside of the second closure component and comprising a plurality of thread turns; and    wherein one of said first thread formation and said second thread formation includes a pad which extends axially from one thread turn of said plurality of thread turns of said one thread formation, said one thread turn of said one thread formation being the last thread turn to be engaged by a respective other of said first and second thread formations in a screwing-on direction of said second closure component to said first closure component, said pad being overrun by said respective other of said first and second thread formations and being of a sufficient height to draw said second closure component in an axial direction on said first closure component to resiliently press said first sealing surface to said second sealing surface.    
     
     
         2 . The threading arrangement of  claim 1 , wherein and said first thread formation comprises a first bottom turn and said second thread formation comprises a second bottom turn, and said pad is formed on said first bottom turn of said first thread formation, and said pad comprises an inclined leading face in a screwing-on, tangential direction to allow said second bottom turn of said second thread formation to overrun said pad to draw said second sealing surface down upon said first sealing surface.  
     
     
         3 . The threading arrangement of  claim 1 , wherein said first closure component comprises a closure body and said second closure component comprises a container neck.  
     
     
         4 . The threading arrangement of  claim 3 , wherein said second closure component includes a dispensing orifice.  
     
     
         5 . The threading arrangement of  claim 1 , wherein said one thread turn comprises a first bottom turn of said plurality of turns of said first thread formation, and wherein said second thread formation comprises a second bottom turn of said plurality of turns, and wherein said first thread formation is arranged to be loosely engaged by said second thread formation until said second bottom turn of said second closure component overruns said pad.  
     
     
         6 . The container closure arrangement according to  claim 1 , 
 wherein said one thread formation comprises said first thread formation, and said second closure component comprises a resilient seal element, said second sealing surface carried on said resilient seal element and arranged to be contacted by said first sealing surface of said first closure component when said second closure component is drawn down onto said first closure component, and said pad comprises a sufficient height to resiliently compress said seal element when said pad is overrun by said second thread formation of said second closure component.    
     
     
         7 . A closure structure, comprising: 
 a container neck having a first sealing surface;    a closure body having a second sealing surface;    a first thread formation on an outside of the container neck and comprising a plurality of thread turns;    a second thread formation on an inside of the closure body and comprising a plurality of thread turns including a bottom turn; and    wherein said first thread formation includes a pad which extends axially from one thread turn of said plurality of thread turns of said first thread formation, said one thread turn being the last thread turn to be engaged by said second thread formation in a screwing-on direction of said closure body to said container neck, said pad being overrun by said bottom turn of said second thread formation and being of a sufficient height to draw said closure body in an axial direction on said container neck to resiliently press said first sealing surface to said second sealing surface.    
     
     
         8 . The closure structure of  claim 7 , wherein said pad comprises an inclined leading face in a screwing-on, tangential direction to allow said bottom turn of said second thread formation to overrun said pad to draw said second sealing surface down upon said first sealing surface.  
     
     
         9 . The closure structure of  claim 7 , wherein said closure body includes a dispensing orifice.  
     
     
         10 . The closure structure of  claim 7 , wherein said first thread formation is arranged to be loosely engaged by said second thread formation until said bottom turn of said closure body overruns said pad.  
     
     
         11 . The closure structure according to  claim 7 , wherein said 
 closure body comprises a resilient seal element, said second sealing surface carried on said resilient seal element and arranged to be contacted by said first sealing surface of said container neck when said closure body is drawn down onto said container neck, and said pad comprises a sufficient height to resiliently compress said seal element when said pad is overrun by said second thread formation of said closure body.