Pet container having inward thread finish

Abstract

A container and a method for making a container having inwardly formed threads are provided. The container includes a body portion having a bottom portion and a sidewall portion. A neck portion is formed above the body portion and defines an opening at a top of the container. The neck portion includes a vertical cylinder portion extending vertically upward from the body portion, the vertical cylinder portion having a thread portion formed as a concave profile around the vertical cylinder portion.

What is claimed is: 
     
         1 . A method of making a blow-molded PET plastic container having an inward thread finish, the method comprising:
 providing a mold having a neck forming surface comprising a first surface configured to form a vertical cylinder portion of a bottle and a projecting portions projecting outward from the first surface that are configured to form helical threads; and   stretching the preform against the mold surface to form a neck portion of the container, the neck portion comprising a vertical cylinder portion having helical threads formed radially inward of the vertical cylinder portion.   
     
     
         2 . The method of  claim 1 , wherein portions of the preform forming the vertical cylinder portions are stretched to a greater length than portions forming an inner surface of the helical threads, the inner surface being radially inward of the vertical cylinder portion. 
     
     
         3 . A container, the container comprising:
 a body portion comprising a bottom portion and a sidewall portion; and   a neck portion formed above the body portion and defining an opening at a top of the container,   the neck portion comprises:
 a vertical cylinder portion extending vertically upward from the body portion, the vertical cylinder portion having a thread portion formed therein, the thread portion formed as a concave profile around the vertical cylinder portion; and 
 a top portion formed at an uppermost part of the vertical cylinder portion and extending in a horizontal direction. 
   
     
     
         4 . The container according to  claim 3 , wherein the thread portion comprises a helical groove that is formed radially inward of and around the vertical cylinder portion. 
     
     
         5 . The container according to  claim 3 , wherein the top portion of the container joints the vertical cylindrical wall at a position that is radially outward of the thread portion. 
     
     
         6 . The container according to  claim 3 , wherein the thread portion comprises multiple non-intersecting grooves. 
     
     
         7 . The container according to  claim 3 , wherein the thread portion comprises an inner surface, an upper surface and a lower surface, the inner surface joining the upper surface and the lower surface, the upper surface and the lower surface extending from different portions of the vertical cylindrical portion. 
     
     
         8 . The container according to  claim 7 , wherein a maximum width between the upper surface and the lower surface is ranges from 0.084 to 0.120 inches. 
     
     
         9 . The container according to  claim 3 , wherein a depth of the thread portion from the vertical cylindrical surfaces ranges from 0.042 to 0.060 inches. 
     
     
         10 . The container according to  claim 4 , wherein the width of the helical groove is less than a width of a portion of the vertical cylindrical portion between adjacent grooves.